THE CAMBRIDGE COMPANION TO
THE "ORIGIN OF SPECIES"
The Origin of Species by Charles Darwin is universally rec-
ognized as one of the most important science books ever
written. Published in 1859, it was where Darwin argued for
both the fact of evolution and the mechanism of natural
selection. The Origin of Species is also a work of great cul-
tural and religious significance, in that Darwin maintained
that all organisms, including humans, are part of a natural
process of growth from simple forms. This Companion com-
memorates the 150th anniversary of the publication of the
Origin of Species and examines its main arguments. Draw-
ing on the expertise of leading authorities in the field, it
also provides the contexts - religious, social, political, liter-
ary, and philosophical - in which the Origin was composed.
Written in a clear and friendly yet authoritative manner, this
volume will be essential reading for both scholars and stu-
dents. More broadly, it will appeal to general readers who
want to learn more about one of the most important and
controversial books of modern times.
Michael Ruse is the Lucyle T Werkmeister Professor of Phi-
losophy and director of the Program in History and Philos-
ophy of Science at Florida State University. The author or
editor of more than thirty books, including Can a Darwinian
Be a Christianl and Darwinism and Its Discontents, he is a
Fellow of the Royal Society of Canada and the recipient of
several honorary degrees.
Robert J. Richards is Morris Fishbein Professor of the History
of Science and director of the Fishbein Center for the History
of Science and Medicine at the University of Chicago. He
has held major fellowships for work in the history and phi-
losophy of biology and is the author of many books, includ-
ing Darwin and the Emergence of Evolutionary Theories
of Mind and Behavior and The Tragic Sense of Life: Ernst
Haeckel and the Struggle over Evolutionary Thought.
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Darwin's diagram of species (marked A to L) supposedly descending from one
genus (not seen). The intervals (marked by roman numerals) represent one
thousand or, perhaps, ten thousand generations. Varieties are represented by
lowercase letters. At level fourteen, we may suppose the original varieties
have become species. "Thus, as I believe, species are multiplied and genera
are formed" [Origin, 120).
Cambridge Collections Online © Cambridge University Press, 2009
The Cambridge Companion to
THE "ORIGIN OF
SPECIES"
Edited by
Michael Ruse
Florida State University
Robert J. Richards
University of Chicago
Rgg Cambridge
WW UNIVERSITY PRESS
Cambridge Collections Online © Cambridge University Press, 2009
CAMBRIDGE UNIVERSITY PRESS
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Cambridge University Press
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© Cambridge University Press 2009
This publication is in copyright. Subject to statutory exception
and to the provisions of relevant collective licensing agreements,
no reproduction of any part may take place without the written
permission of Cambridge University Press.
First published 2009
Printed in the United States of America
A catalog record for this publication is available from the British Library.
Library of Congress Cataloging in Publication Data
Ruse, Michael.
The Cambridge companion to the Origin of species / Michael Ruse,
Robert J. Richards.
p. cm.
Includes bibliographical references and index.
isbn 978-0-521-87079-5 (hardback) -isbn 978-0-521-69129-1 (pbk.)
1. Darwin, Charles, 1809-1882. On the origin of species 2. Evolution (Biology)
3 . Natural selection. I. Richards, Robert J. II. Title.
OH365.08R865 2009
576.8'2-dc22 2008000484
isbn 978-0-521-87079-5 hardback
isbn 978-0-521-69129-1 paperback
Cambridge University Press has no responsibility for the persistence or
accuracy of urls for external or third-party Internet Web sites referred to in
this publication and does not guarantee that any content on such Web sites is,
or will remain, accurate or appropriate. Information regarding prices, travel
timetables, and other factual information given in this work are correct at
the time of first printing, but Cambridge University Press does not guarantee
the accuracy of such information thereafter.
Cambridge Collections Online © Cambridge University Press, 2009
CONTENTS
3
4
5
6
7
List of Contributors
Note on Citations
Foreword by Edward O. Wilson
Introduction
The Origin of the Origin
MICHAEL RUSE
Darwin's Analogy between Artificial and
Natural Selection in the Origin of Species
MARK A. LARGENT
Variation and Inheritance
ROBERT OLBY
page vn
xiii
xv
xvii
14
30
Darwin's Theory of Natural Selection and Its
Moral Purpose 47
ROBERT J. RICHARDS
Originating Species: Darwin on the Species Problem 67
PHILLIP R. SLOAN
Darwin's Keystone: The Principle of Divergence 87
DAVID KOHN
Darwin's Difficulties 109
A. j. LUSTIG
Cambridge Collections Online © Cambridge University Press, 2009
vi Contents
8 Darwin's Geology and Perspective on the
Fossil Record 129
SANDRA HERBERT AND DAVID NORMAN
9 Geographical Distribution in the Origin of Species 153
PETER J. BOWLER
10 Classification in Darwin's Origin 173
RICHARD A. RICHARDS
1 1 Embryology and Morphology 1 94
LYNN K. NYHART
12 Darwin's Botany in the Origin of Species 216
VASSILIKI BETTY SMOCOVITIS
13 The Rhetoric of the Origin of Species 237
DAVID J. DEPEW
14 "Laws impressed on matter by the Creator"?
The Origin and the Question of Religion 256
JOHN HEDLEY BROOKE
15 Lineal Descendants: The Origin's Literary Progeny 275
GILLIAN BEER
1 6 The Origin and Political Thought: From
Liberalism to Marxism 295
NAOMI BECK
17 The Origin and Philosophy 314
TIM LEWENS
18 The Origin of Species as a Book 333
MICHELE KOHLER AND CHRIS KOHLER
Bibliography 353
Index 373
Cambridge Collections Online © Cambridge University Press, 2009
CONTRIBUTORS
Naomi Back received her Ph.D. from the University of Paris i
(Pantheon-Sorbonne) in 2005 . She is currently employed as Assistant
Professor in the Social Sciences Collegiate Division at the University
of Chicago.
Gillian Beer is Edward VII Professor Emeritus at the University
of Cambridge. She is a Fellow of the British Academy and of the
Royal Society of Literature and a Foreign Honorary Member of the
American Academy of Arts and Sciences. Among her books are Dai-
win's Plots (second edition 2000), Open Fields: Science in Cultural
Encounter (1996), and Virginia Woolf: The Common Ground (1996).
She has recently been writing about rhyming and about the Alice
books, as well as preparing new work on Darwin and consciousness.
She is the president of the British Comparative Literature Associa-
tion and has twice been a judge for the Booker Prize.
Peter J. Bowler is Professor of the History of Science at Queen's
University, Belfast, Northern Ireland. He is a Fellow of the British
Academy and a former president of the British Society for the History
of Science. He has published widely on the history of evolutionary
theory and is now completing a book on popular science in early
twentieth- century Britain.
John Hedley Brooke held the Andreas Idreos Professorship of Science
and Religion and directorship of the Ian Ramsey Centre at Oxford
University from 1999 to 2006. He is an Emeritus Fellow of Harris
Manchester College, Oxford, and Honorary Professor of the History
of Science at Lancaster University and in 2007 was Distinguished
Fellow at the Institute of Advanced Study, University of Durham.
Vll
Cambridge Collections Online © Cambridge University Press, 2009
viii Contributors
His books include Science and Religion: Some Historical Perspec-
tives (Cambridge University Press, 1991), Thinking About Matter:
Studies in the History of Chemical Philosophy (1995), and (with
Geoffrey Cantor) Reconstructing Nature: The Engagement of Sci-
ence and Religion (Clark, 1998). He is currently president of the
UK Forum for Science and Religion. His most recent publications
include Heterodoxy in Early Modern Science and Religion, coedited
with Ian Maclean (2005) and Religious Values and the Rise of Sci-
ence in Europe, coedited with Ekmeleddin Ihsanoglu (2005).
David J. Depew is Professor of Communication Studies and Rhetoric
of Inquiry at the University of Iowa. He works in the history,
philosophy, and rhetoric of biology, both ancient and modern. He
is the coauthor, with Marjorie Grene, of Philosophy of Biology:
An Episodic History (Cambridge University Press, 2004) and, with
Bruce H. Weber, of Darwinism Evolving: Systems Dynamics and the
Genealogy of Natural Selection (1994). With Weber, he has coedited
a number of collections, most recently Evolution and Learning: The
Baldwin Effect Reconsidered (2003). He has written articles on the
bearing of Aristotle's biological treatises on his social and political
theory and on how Aristotle and Darwin can most accurately be
compared. With John P. Jackson, he is currently working on a book
about how Darwinians have intervened in American social and polit-
ical controversies.
Sandra Herbert is Professor of History at the University of Mary-
land-Baltimore County and a Fellow of the American Association
for the Advancement of Science and in 2006-07 was Distinguished
Visiting Scholar at Christ's College, Cambridge. Her book Charles
Darwin: Geologist (2005) has received awards from the American
Historical Association, the Geological Society of America, the His-
tory of Science Society, and the North American Conference on
British Studies.
Chris Kohler became an antiquarian bookseller in 1 9 6 1 when he was
eighteen, and Michele Kohler joined his firm after their marriage
in 1973. They put together collections of books that they sell to
university and national libraries throughout the world. They spent
twenty years building the most comprehensive collection of books
and autograph letters by and about Charles Darwin that has ever
Cambridge Collections Online © Cambridge University Press, 2009
Contributors ix
been assembled, which they sold to the Natural History Museum in
London.
David Kohn is General Editor of the Darwin Digital Library of Evolu-
tion at the American Museum of Natural History and Robert Fisher
Oxnam Professor of the History of Science Emeritus at Drew Uni-
versity. He has edited Charles Darwin's Transmutation Notebooks
and is currently writing an intellectual history of Darwin's botany.
Mark A. Laigent is an historian of biology. He is Assistant Professor
of Science Policy and directs the Science, Technology, Environment
and Public Policy Specialization at James Madison College at Michi-
gan State University. He earned his Ph.D. from the University of
Minnesota's Program in History of Science and Technology and has
taught American history and history of science courses at Oregon
State University and the University of Puget Sound. His research
and teaching focus on the role of biologists in public affairs and in
the history of nineteenth- and early twentieth-century biology. He
has published on the history of the evolution/creation debates, evo-
lutionary theory, and the American eugenics movement; his most
recent book is Breeding Contempt: The History of Coerced Steril-
ization in the United States (2007).
Tim Lewens works in the Department of History and Philosophy of
Science at the University of Cambridge. He is the author of Darwin
(2007) and Organisms and Artifacts (2004).
A. J. Lustig is Assistant Professor of History at the University of
Texas at Austin. She is the coeditor, with Robert J. Richards and
Michael Ruse, of Darwinian Heresies (2004) and is currently writ-
ing a book on explanations of altruism in biology and society since
Darwin.
David Norman is working on describing the early Jurassic dinosaurs
Heterodontosaurus and Scelidosaurus. He is currently directing a
major new exhibition entitled Charles Darwin the Geologist at the
Sedgwick Museum of Earth Sciences, University of Cambridge. He
is also developing exhibitions on Charles Darwin's life as a student
at Christ's College, Cambridge, and is a member of the committee
organizing the Darwin 2009 Festival at the University of Cambridge.
Further, he is coordinating research on Darwin's historical work as
Cambridge Collections Online © Cambridge University Press, 2009
x Contributors
a geologist and new geological research on material collected from
the Galapagos Islands in 2007. He has written several prize-winning
books on dinosaurs, their evolution and biology, as well as numerous
scientific papers on related topics, including a few on the history
of science with respect to fossil reptiles. He was the Asher Tunis
Distinguished Research Fellow (Paleobiology) at the Smithsonian
Instititution, Washington, D.C., for 2000-02 and a Visiting Scholar
at St. John's College, Oxford, in 2006. He is the director of the Sedg-
wick Museum of Earth Sciences, University of Cambridge; an Odell
Fellow in Natural Sciences at Christ's College, Cambridge; and a
University Reader in Vertebrate Paleobiology at the University of
Cambridge.
Lynn K. Nyhart teaches history of science at the University of
Wisconsin-Madison. She is the author of Biology Takes Form: Ani-
mal Morphology and the German Universities, 1 800-1900 (1995),
and of a forthcoming book, Modern Nature, on natural history
reform movements in nineteenth- century Germany. Her specialty
is the history of evolutionary thought in its various guises.
Robert Olby is a retired professor of the history of science at Pitts-
burgh University. He is the author of many books on the history of
genetics, including the classic The Path to the Double Helix: The
Discovery of DNA (1994).
Richard A. Richards is Assistant Professor of Philosophy at the Uni-
versity of Alabama and Associate Professor of Philosophy at Yeshiva
University in New York City. He is the author of articles on Darwin
and on taxonomy. For the first decade of his adult life, he was a
professional ballet dancer.
Phillip R. Sloan is Professor in the Program of Liberal Studies and
in the Graduate Program in History and Philosophy of Science at
the University of Notre Dame. His research specializes in the his-
tory and philosophy of life science from the early modern period
to contemporary molecular biology. His writings include studies of
Buffon, Darwin, and Richard Owen and on the history of classifica-
tion in biology. He is currently working on a book on the conception
of life in contemporary biophysics.
Vassiliki Betty Smocovitis is Professor of the History of Science
in the Departments of Zoology and History at the University of
Cambridge Collections Online © Cambridge University Press, 2009
Contributors xi
Florida and is affiliate in the Botany department. She is the author
of Unifying Biology: The Evolutionary Synthesis and Evolutionary
Biology (1996). Her research interests include the history of plant
evolutionary biology; she is currently completing a biography of G.
Ledyard Stebbins.
Cambridge Collections Online © Cambridge University Press, 2009
Cambridge Collections Online © Cambridge University Press, 2009
NOTE ON CITATIONS
Some works are cited often, and for convenience their titles have
been abbreviated and used in the text.
Barrett, P. PL, P. J. Gautrey, S. Herbert, D. Kohn, and S. Smith, editors. 1987.
Charles Darwin's Notebooks, 1836-1844. Ithaca, NY: Cornell University
Press. [Notebooks)
Darwin, C. 1859. On the Origin of Species by Means of Natural Selection,
or the Preservation of Favoured Races in the Struggle for Life. London:
John Murray. [Origin)
Darwin, C. 1909. The Foundations of the Origin of Species: Two Essays
Written in 1842 and 1844. Edited by F. Darwin. Cambridge: Cambridge
University Press. [Foundations)
Darwin, C. 1958. The Autobiography of Charles Darwin, 1809-1882. Edited
by N. Barlow. London: Collins. [Autobiography)
Darwin, C. 1959. The Origin of Species by Charles Darwin: A Variorum
Text. Edited by M. Peckham. Philadelphia: University of Pennsylvania
Press. [Variorum)
Darwin, C. 1975. Charles Darwin's Natural Selection, Being the Second
Part of His Big Species Book Written from 1856 to 1858. Edited by R. C.
Stauffer. Cambridge: Cambridge University Press. [Species Book)
Darwin, C. 1985-. The Correspondence of Charles Darwin. Cambridge:
Cambridge University Press. [Correspondence)
Darwin, F. 1887. The Life and Letters of Charles Darwin, Including an
Autobiographical Chapter. London: John Murray. [Letters)
Darwin, F., and A. C. Seward, editors. 1903. More Letters of Charles Darwin.
London: John Murray. [More Letters)
xni
Cambridge Collections Online © Cambridge University Press, 2009
Cambridge Collections Online © Cambridge University Press, 2009
EDWARD O. WILSON
FOREWORD
One hundred and fifty years past its publication, I believe we can
safely say that the Origin of Species is the most important book of
science ever written. Indeed, given its importance to all of human-
ity and the rest of life, it is the most important book in any cate-
gory. No work of science has ever been so fully vindicated by subse-
quent investigation, or has so profoundly altered humanity's view of
itself and how the living world works. The theory of natural selec-
tion continues to gain relevance to the things that matter most to
humanity - from our own origins and behavior to every detail in the
living environment on which our lives depend. Little wonder that
the adjective "Darwinian," sometimes lowercased to "darwinian"
as a tribute to its fixity, far outranks "Copernican," "Newtonian,"
and "Mendelian" in the frequency of usage.
The Origin won the day quickly for such a revolutionary proposal,
so much so that Darwin could confidently publish The Descent of
Man only twelve years later. It succeeded not just for the mass of
evidence adduced to support evolution but because of the clarity
and authority of its text. The quality of the mind that erected it
did not come from the blue. For nearly three decades, extending
from the departure of HMS Beagle from Plymouth on December
31, 183 1, to the day in 1859 tne Origin was sent to press, Darwin
remained almost continuously absorbed in scientific natural history.
He inhabited this subject, and he lived it. And fortunately, the middle
of the nineteenth century was a time that so little was known about
nature in the rest of the world, so few unifying concepts existed
to guide the collection of data, that every fact, every specimen was
valued. Darwin's mind was an open vessel. By absorbing with little
XV
Cambridge Collections Online © Cambridge University Press, 2009
xvi Foreword
discrimination those domains of natural history most relevant to
geology and evolutionary biology, he became enormously learned.
In preparing my recent anthology entitled From So Simple a Begin-
ning (2006), I read for the first time in chronological order all four of
Darwin's greatest books, Voyage of the Beagle (1845), the Origin of
Species (1859), The Descent of Man (1871), and The Expression of the
Emotions in Man and Animals (1872). These are, I can assure you,
the four to read, and straight through if you can. It is impossible to
imagine a higher quality of original intellectual exposition. Taken in
sequence, the four books reveal the development of a mind priming
itself to address the greatest of subjects during the most opportune
of times to do so. Darwin must have been continuously exhilarated
by what he had come upon. Galileo had his telescope. Leeuwenhoek
had his microscope. Darwin had his idea.
Charles Darwin is the most written-about scientist in history.
The reader may well ask, in picking up the present Companion,
whether we need more: do we need more, even as part of a centennial
celebration? The answer is yes! Light continues to be thrown by
evolutionary thought on more and more subjects. The human self-
image continues to grow in depth and clarity as a result. All this is
worth an ever-evolving commentary. The history, provenance, and
impact of the Origin and Darwin's other great books deserve repeated
rounds of assessment.
Cambridge Collections Online © Cambridge University Press, 2009
INTRODUCTION
In 1859, the English naturalist Charles Robert Darwin published his
major work, the Origin of Species. In this work, he argued that all
organisms living and dead are the end result of a long, slow, natural
process of development from forms far simpler and that indeed all
life, by reason of its descent from but a few ancestors, is related. He
also proposed a mechanism, natural selection, meaning that only a
few survive and reproduce and that success in this process is on aver-
age a function of the distinctive features of organisms - over time,
this leads to change, change that is in the direction of adaptation.
Eyes, ears, noses, leaves, trunks, flowers, flippers, fins - these are
the things that are produced by evolution, and these are the things
crucial for survival and reproduction.
At once, it was recognized that the Origin was a major work
of science. Indeed, it was seen as a major event in the history of
Western civilization. As Copernicus had expanded space, so Dar-
win expanded time. Moreover, this was something that impinges on
human beings. The Origin is not directly about humans. The only
explicit reference is an almost throwaway passage at the end of the
book. "Light will be thrown on the origin of man and his history."
But no one was fooled. Humans may be important, but our impor-
tance must be tempered by our shared links with the rest of life.
What perhaps could not have been seen back in 1 859 was the extent
to which Darwin and his book would be subjects of intense interest
and controversy at the beginning of the new millennium, here in
the first decade of the twenty-first century. Thinking of other major
events in the years of the Origin, clearly the Crimean War and the
Indian Mutiny had far-reaching effects - the former if only for med-
ical care in battle and the latter eventually for the independence of
XVll
Cambridge Collections Online © Cambridge University Press, 2009
xviii Introduction
the subcontinent. But today these are matters of historical interest
and not of contemporary controversy. Not so the Origin. In part
because of the controversy about creationism, in part because the
mechanism of natural selection is debated vigorously in the science
community, in part because Darwin's thinking does strike so fun-
damentally at the visions that we all have of ourselves, the Origin
itself is still reprinted, reread, discussed and debated.
This Cambridge Companion has been written, edited, and pub-
lished precisely because the Origin is still today a work of vital
significance and interest. It is not a substitute for reading the Ori-
gin itself. We suggest that you have a copy of the Origin beside you
as you open this volume - for reasons that will be made clear, we
suggest that you use the first edition of the Origin, and it will be
easiest to use the readily available facsimile, for it is to this that the
contributors in this volume refer. The order of the contributions to
this volume is straightforward. After an initial introduction, the top-
ics of the Origin are introduced and discussed in order. Then there
are several essays on issues that come out of the Origin. We stress
that this is a work on the Origin and not on Darwin or evolution
generally. As always with Cambridge Companions, the intent is to
introduce pertinent ideas to readers new to the issues, but at the
same time to try to offer thoughts that the more experienced and
professional will find relevant and challenging.
The volume opens with a piece by one of the editors, Michael
Ruse, that gives some background to the Origin, why it was written
and when. There is an ongoing debate about the long interval of time
between the moments at which Darwin thought up his ideas and the
date of eventual publication. Why was there this gap, and indeed is
it even right to speak in terms of a "gap"? At the same time, the
piece gives an overview of the work, suggesting that - as Darwin
himself said - it is "one long argument" and not simply a bunch
of ideas thrown together. It is suggested that the work is skillfully
constructed in the light of the dictates of the leading methodologists
of science active when Darwin was a young man, but also that in
judging the style one should take note of the sponsors of the natu-
ralist, and why he would be trying to meet their approval and gain
their sympathy. Also discussed are a number of issues arising from
the Origin, for instance, the extent to which one can truly say that
Cambridge Collections Online © Cambridge University Press, 2009
Introduction xix
Darwin was working in a British tradition as opposed to the style
and methods of various continental thinkers.
The Origin opens with an extended discussion of the work of
animal and plant breeders and the uses that they make of artifi-
cial selection. This is the topic of Mark A. Largent's paper. After a
careful discussion of the information offered by Darwin, including a
recognition of the ways in which Darwin separated out the differing
intentions of and effects produced by the breeders - including a dis-
cussion of something Darwin called "unconscious selection" that
he thought very important - Largent takes up a topic about artificial
selection that is much discussed, namely, its role in the Origin. Is it
just a heuristic device to get the reader ready for natural selection, or
does it have a deeper role, that of making natural selection and the
evolution consequent upon its action more evidentially plausible?
Largent argues we can answer questions like these only by consid-
ering the extended work that Darwin himself did on breeding such
organisms as pigeons.
Robert Olby tackles the important question of variation. In order
for natural selection to work, there must be a renewable supply of
variation. If there is not, then selection will soon have used up every-
thing and ongoing change will grind to a halt. Darwin had no theory
of heredity - what we call "genetics" - and although he did later
come up with (what we now consider) a misguided theory, it was
never introduced into the Origin. Olby looks at the data that Darwin
did introduce into the Origin, and at the kinds of speculations that
he made about it. Olby also looks at the changes that Darwin made
through various editions of the Origin, in the light of his own work
and the criticisms of others. Finally, Olby tackles the much-debated
question of whether Darwin could and would have put his theory
on a much firmer basis had he read the work of the Moravian monk
Gregor Mendel, the man who is today regarded as the father of mod-
ern genetics. Olby suggests that an adequate answer to this question
is far from obvious.
We have next a discussion of the linchpin of Darwin's thinking,
natural selection. Robert J. Richards (the other editor of this vol-
ume) tackles this topic, taking us through the discovery of natural
selection as a force for change, together with a secondary mecha-
nism that Darwin called "sexual selection," and on to the eventual
Cambridge Collections Online © Cambridge University Press, 2009
xx Introduction
discussion of selection in the Origin. Richards's discussion uncov-
ers a major difference between two camps of contemporary Darwin
scholars (a difference that separates the two editors of this Com-
panion!) - between those, like Ruse, who think that Darwin was
the quintessential English thinker and that natural selection was
a mechanism very much in the mold of the industrialists of the
eighteenth century, and those, like Richards, who see Darwin much
more in the continental Romantic tradition and who therefore see
selection as something contributing to this tradition, being focused
essentially on humans and their interests, their moral concerns, and
their unique, high place in the world, which they owe to the world-
wide progressive force of nature.
One still sometimes hears people say that although Darwin's book
was titled the Origin of Species, in fact the topic of species is virtually
absent from the book. This is simply not true, for there is much said
in the Origin both on the nature of species in a world of evolution and
on the reasons for their coming into being - the next chapter shows
the latter in some detail. It is true, however, that one gets no explicit
formal discussion of the topic of species, and it is Phillip R. Sloan's
task to pull together what Darwin has to say about species in the
Origin and to put the discussion in a historical context. This Sloan
does by going back and looking at earlier (especially eighteenth-
century) discussions of classification (systematics) and then at how
Darwin tackled the topic in various writings up to and including
the Origin. An important part of Sloan's discussion focuses on the
debate after publication of the Origin and how Darwin's critics and
friends tried to incorporate his thinking into their discussions and
scientific forays.
Following on Sloan's discussion, David Kohn tackles a very impor-
tant topic in the Origin (the word "keystone" in the title to the chap-
ter is a word that Darwin himself used about the topic). How is it
that organisms diverge in kind, and more importantly, why do they
do so? Why are not all organisms identical? If you look at Darwin's
notebooks, you can see that from the beginning he is wrestling with
this problem, but it was not until the 1850s that he got on top of
it, seeing that it is through divergence and diversification that many
more organisms can exist and be supported than otherwise. Kohn
points to the very great significance of metaphor for Darwin - in
this case, the industrialist's metaphor of the division of labor. The
Cambridge Collections Online © Cambridge University Press, 2009
Introduction xxi
creation of organisms that are different and adapted for different ends
means that more life can flourish than would happen otherwise. As
Kohn points out, this is the basis for another of Darwin's celebrated
metaphors, the tree of life.
A. J. Lustig takes on two linking chapters in the Origin, first
that dealing with organs of great perfection and second that dealing
with instinct. The former basically completes the case for evolu-
tion through selection. Lustig shows how Darwin cleverly turns the
argument on its head, or at least on its side, arguing that although
we cannot see the evolution of perfection through time, we can in
space, by setting up a series of existent organisms from the simplest
to the most complex. Lustig also notes how here (as elsewhere) there
are theological concerns lying beneath the most secular of discus-
sions. The latter chapter, on instinct, starts to take us to the second
part of the Origin, where Darwin applies his theory across a wide
range of topics and problems. The discussion is important both for
the extent to which it shows that behavior is as much a subject
for selection and evolution as are physical features, and also for the
ways in which Darwin had to wrestle with what today is known as
the units-of-selection problem. In social organisms, like the ants and
bees, was selection working on the individual insect or on the hive
as a whole, and why does this matter?
When the layperson thinks of evolution, at once the fossil record
comes to mind. Indeed, how often has one heard someone say that
they believe in evolution because of the fossils - or, alternatively,
that they do not believe in evolution because of the fossils! As it
happens, however, although the fossil record is clearly crucial for
the belief in evolution, when it comes to mechanisms there is often
debate - who, after all, could see selection working on the trilobites
or the dinosaurs ? Darwin realized this to the full, and his extensive
discussion in the Origin of paleontology is concerned in major part
with answering problems and objections. However, as Sandra Her-
bert and David Norman show in their contribution, there is more
to the story than this, and in the Origin Darwin is also concerned
to make the positive case for evolution and selection as based on
the fossil record. Note how some of the things that Darwin has to
say about the record - for instance, about the status of higher organ-
isms, especially humans - clearly bear on topics mentioned earlier.
(Although Darwin makes explicit mention of humans only at the
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xxii Introduction
end of the Origin, throughout the work there are hints about and
references to our species.)
Next, Peter Bowler takes up Darwin's discussion of geographical
distribution. It is well known that this was an important topic for
Darwin, because as a young man, when he was the ship's naturalist
on HMS Beagle, he had been tremendously impressed by the dis-
tributions of the birds and reptiles on the Galapagos Archipelago.
Why do you have different finches and mockingbirds and tortoises
on islands within sight of each other, when on the mainland there
is far less biodiversity? And why are the animals of the Galapagos
like the animals of the South American continent and not like those
of Africa, whereas the animals of the Canary Islands are like those
of Africa and not like those of South America? These are facts that
Darwin uses to bolster his case for evolution against the religious
who want everything to be the function of creative miracle. Bowler
shows how Darwin fits his discussion into a pattern that mirrors that
of the earlier discussion of paleontology - one dealing with space and
the other with time.
The penultimate chapter of the Origin (the final is recapitulatory)
is something of a grab-bag discussion, as Darwin starts to clean up
the topics he has so far left undiscussed. The first is that of classifi-
cation or systematics, and Richard A. Richards's discussion of this
subject is a nice complement to the earlier discussion of species by
Phillip Sloan. Richards also puts things in historical context, talk-
ing both of the system of the Swedish taxonomist Linnaeus in the
eighteenth century and of classificatory suggestions of the early nine-
teenth century, including the rather odd quinary system of William
MacLeay. Richards also shows how very crucial was the thinking
about homology and analogy by the anatomist Richard Owen, a man
who was to become much hated by the Darwinian party. This is all
a springboard for a discussion of classification in the Origin, where
Darwin shows that his theory explains the possibility and nature of
organic classification and how in turn this possibility and nature (in
a kind of feedback way) make plausible Darwin's theory. Richards
also goes on to show how Darwin's thinking was to impinge on the
thinking of classifiers after the Origin.
Darwin was very proud of his discussion of embryology in the Ori-
gin. The big puzzling question was why exactly it is that, although
the adults of different species may be very different, their embryos
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Introduction xxiii
are often nigh identical - the naked eye cannot distinguish a human
embryo from that of a dog. Darwin saw that this all followed from the
different selective pressures on organisms at different times of their
lives. Embryos are basically under the same conditions, whereas
adults are not, and hence they get driven apart. But there was more
to embryology than this, and Lynn K. Nyhart's contribution also
focuses on these extra facts and problems, particularly the extent
to which Darwin shared the views of the continental embryologists
who thought that there were parallels between the development of
the individual organism and the history (whether evolutionary or
not) of the group or race. Obviously these issues take us right to
the heart of the debate about the extent(s) to which Darwin can be
considered a naturalist in the English tradition or a more Romantic
thinker in the continental line.
We now start on a slightly different track. The main arguments
of the Origin have been covered. The contributions from now on
deal with particular issues arising from the Origin, issues that merit
discussion in their own right. (For this reason, there is no longer
any binding reason behind the ordering of the contributions, and the
reader should feel free to read them in any order.) Vassiliki Betty
Smocovitis writes about Darwin's botany in the Origin. Although
we tend to think of Darwin as an animal man - finches, pigeons, tor-
toises, bees, and so forth - the study of plants was always something
of prime importance for him, and indeed after the Origin most of his
own empirical research was on plants, starting with a sprightly little
book on orchids. Smocovitis shows how plants do in fact play a large
role in the Origin, especially in the early chapters. There is discus-
sion of them in the world of breeders, as a source for variation and
for the argument that varieties can turn into species, for refining the
meaning of the struggle for existence, as well as for examples of
fantastic adaptive abilities. Smocovitis argues that in many respects
Darwin was way ahead of his time and that his evolutionary specu-
lations about plants were fully appreciated only in the middle of the
last century, almost a century after the Origin first appeared.
David J. Depew raises topics that have been gaining increasing
scrutiny from scholars recently, topics that more traditional scien-
tific and philosophical approaches tend to miss. He is concerned with
Darwin's style and his argumentative strategy. One very interesting
point that Depew makes speaks to an issue that has often puzzled
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xxiv Introduction
readers of the Origin, namely, who exactly does Darwin take to be
his opponents? He often speaks of religiously based opposing ideas,
but it is not easy to see exactly who the people holding such ideas
might be. Depew suggests that this fuzziness might have been delib-
erate. Darwin did not want to make too strong and clear a case for
the opposition because readers might be swung to this opposition!
Depew also raises a topic that has been discussed since Aristotle,
namely, the role of metaphor in thought and especially in scientific
thought. There is much use of metaphor in the Origin, and Depew's
question is about its use and dispensability. Could one have Darwin's
theory without all of the flowery language?
What about religion and the Origin ? Fortunately, as John Hedley
Brooke shows in his contribution, we know a lot about Darwin's
religious beliefs, starting with a fairly literal Anglicanism when at
college, which on the Beagle voyage turned into a kind of deism -
God as unmoved mover, Who works through unbroken law - and
finally towards the end of his life turns again into a form of agnosti-
cism, so favored by many leading Victorian intellectuals. We know
also that it was never really science that changed Darwin's think-
ing about religion, but other generally more theological issues like
hellfire and damnation. Brooke focuses much of his discussion on
the religion of the Origin, arguing that Darwin at that time was no
atheist or even agnostic, but trying to work out a form of deism,
which frees God from the details but puts Him behind the over-
all working and excellence of the living world. Brooke also shows
that the religious response to the Origin was by no means uniform,
and that reactions varied from enthusiastic acceptance to outright
hostility. Matters were also complicated by the fact that the Angli-
can Church in Britain had other more pressing issues to deal with,
especially the trends in continental theology ("higher criticism"),
which was throwing much uncomfortable light on the literal claims
of Holy Scripture. Whatever else, Brooke shows that the relationship
between the Origin and religion was complex and multifaceted.
As a young man, Darwin loved music and literature and the arts
generally. As an old man, he regretted that, under the pressure of a life
of science, his feeling for the aesthetic side of human existence had
withered and gone. At most, he wanted a novel with a good story, a
happy ending, and preferably a pretty heroine. In fact, he sold himself
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Introduction xxv
short, for it is clear that as a writer he always showed the influence
of great works of creative art, novels and poetry, as well as related
volumes of travel and the like. The Origin certainly exhibits this. In
her contribution, Gillian Beer shows that the relationship between
evolution, especially Darwin's evolution, and literature - novels and
poetry - has always been much closer than many realize and that
Darwin's thinking has been a rich source of inspiration for authors,
from the creators of the very greatest works of fiction, notably George
Eliot's Middlemarch, down to novelists and poets writing today. Beer
shows also how this influence has extended from the most sober and
widely admired works to what can only be described as light fiction
of the frothiest kind. Taizan of the Apes is influenced by the Origin
just as much as Thomas Hardy's Jude the Obscure. Through Beer's
essay, we start to grasp how the Origin has been as much a cultural
influence as a simple and pure work of science.
Naomi Beck takes up the question of the influence of the Origin
of Species on political thinking. This is a vast subject, and she dis-
tills the discussion down to three important responses to the Origin.
First, Beck looks at the reactions of the man who in that day was even
more closely identified with evolution than Darwin, namely, Her-
bert Spencer. She shows that although Spencer welcomed the Ori-
gin with enthusiasm, in fact what he did (perhaps typically) was to
read Darwin through his own progress-tinted spectacles, and that
the Darwin who found his way into Spencer's writings owed little
to the efforts of the author of the Origin. Clemence Royer, the first
translator of the Origin into French, was an ardent progressionist
and advocate of forward-looking movements, from republicanism
to feminism. The way she introduced the Origin may have given
her and her admirers great satisfaction, but it made the rather staid
author of the book itself very uncomfortable. Finally, there are the
fathers of Marxism, Karl Marx himself and his great supporter and
collaborator Friedrich Engels. They too praised Darwin - Marx par-
ticularly was much in the camp of those who saw Darwin as a very
English thinker - but eventually their own thoughts and conclusions
were little related to the ideas of the Origin. Finishing Beck's piece,
one might conclude that the Origin is a little bit like tofu - it can
take on flavorings of many kinds, according to the wishes of the
chef.
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xxvi Introduction
Darwin was not a philosopher, and the Origin is not a work of
philosophy. Nevertheless, Darwin was an educated Englishman; he
had read philosophy as part of this education - Plato, the British
empiricists, some continental thinkers (his later work The Descent
of Man shows a keen appreciation of Kant), and most particularly the
methodologists of science of his day. Tim Lewens teases out these
themes, particularly the influence of the methodologists. Lewens has
much to say about what today is regarded as a particularly important
kind of scientific strategy, namely, the use of "inferences to the best
explanation," where one gathers up the information and tries then
to infer the best overall explanation of what is empirically at stake.
Lewens argues that this is an important part of the argumentation
of Darwin and that the chief influence here was the astronomer
and philosopher of science John Herschel. Seeing how today we are
still embroiled in disputes about Darwin and his Origin, the reader
might compare Lewens's account of Darwin's methodology to the
rather different one given in the introductory essay of Ruse.
Finally, Michele and Chris Kohler talk about the Origin as a phys-
ical object - what sort of book it was, how it was published and
distributed, what it cost, and all of those sorts of matters. They
also trace the publishing history of the Origin, first in English and
then in translation. Particularly interesting are their comparisons
of the Origin's fate to that of other well-known works on evolu-
tion, notably Robert Chambers's anonymously published Vestiges
of the Natural History of Creation. The Origin holds its own, but
not much more than that. However, do note the interesting point
that the Kohlers make about the purchase of the Origin by lending
libraries. The actual readership of the Origin, in whole or in part,
may have been large. Among other interesting facts that the Kohlers
have unearthed is the way in which the first edition of the Origin
has shot up in value in recent years. The book may never sell in its
lifetime what a book on wizards sells in its first twenty-four hours,
but the original now costs what no scholar could ever afford. Let
us hope that the tax laws incline rich collectors to give to research
libraries, so that all can continue to enjoy the great work by a great
scientist.
It remains now only for us as editors to thank Cambridge Uni-
versity Press for letting us produce The Cambridge Companion to
the "Origin of Species," to thank our contributors for writing such
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Introduction xxvii
splendid pieces, to thank the world's most distinguished living evo-
lutionary biologist, Edward O. Wilson of Harvard University, for
writing a Foreword, and to thank the William and Lucyle T. Werk-
meister Fund of Florida State University for supporting a conference
where early versions of these contributions could be presented and
discussed by all.
Cambridge Collections Online © Cambridge University Press, 2009
Cambridge Collections Online © Cambridge University Press, 2009
MICHAEL RUSE
1 The Origin of the Origin
Charles Robert Darwin was born in 1 809. His great book, the Origin
of Species, was published in 1859, when he was fifty. He was to
live another twenty-plus years, dying in 1882, by which time the
Origin had gone through six editions and been extensively revised
and rewritten. It used to be the case that it was the sixth edition
of 1872 that was most frequently reproduced, but more recently
scholars have insisted that the first edition is the really important
one - we not only see Darwin's thinking in its original form but
the revisions today are often judged to have been made for less than
worthy reasons (in the sense that the criticisms now no longer seem
so forceful). It is therefore the first edition that will be the focus of
this piece, and my question opening this volume is about its genesis,
and the implications that this had for the actual book that Darwin
produced. While I do not think that the Origin is a particularly
mysterious book, I believe that there are aspects to it that are not
quite as obvious as we today often assume.
THE ROUTE TO DISCOVERY
Undistinguished at school, Darwin went first to the University of
Edinburgh to study medicine and then (after that proved not to be
to his liking) to the University of Cambridge to prepare for the life
of an Anglican clergyman. (Janet Browne's [1995, 2002] biography
is definitive.) We know now that, although Darwin had no formal
training as a biologist, by the time he graduated (in 183 1) he not
The late Sydney Smith once wrote a paper with the same title, and in using it again I
show how much I owe to his friendliness and scholarship.
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1 MICHAEL RUSE
only was showing an aptitude for science but also was long versed in
the ways of empirical study and research. From early years, Charles
and his older brother Erasmus had played with chemical ideas and
experiments, and at both universities he had immersed himself in
the active groups of naturalists and empirical inquirers. At the end
of 1831, Darwin joined HMS Beagle, about to start what proved to
be a five-year trip mapping the coast of South America and then
going on around the world before returning home. Darwin started
as a kind of gentleman companion to the captain, Robert Fitzroy,
but soon became the de facto ship's naturalist, in which role his
earlier scientific activities and training served him very well. The
notebooks that he kept show that he was serious and competent right
from the start. (Sandra Herbert [2005] is very insightful on Darwin's
move into serious science.)
The time on the Beagle was important for many reasons, not the
least of which was that, being away from his Cambridge mentors,
Darwin was forced to think independently. This was shown partic-
ularly in geology, the science that was most important to him in
these early years. Darwin became enthused with the uniformitarian
thinking of Charles Lyell in his Principles of Geology (1830-33) and
broke with the catastrophism of people like Adam Sedgwick (1831),
a professor of geology at Cambridge and the man who had taken Dar-
win on a crash course in Wales in the summer of 1831. In religion,
the trip was important because Darwin's rather literalistic Chris-
tianity started to fade and he became something of a deist, believing
in God as unmoved mover and that the greatest signs of His powers
are the workings of unbroken law rather than signs of miraculous
intervention.
Most significantly, perhaps because he was now thinking of God
as someone Whose greatness is evidenced by unbroken law rather
than by miracle, Darwin started on the path to evolution. It is gen-
erally agreed that Darwin (who knew about evolutionary ideas from
reading Zoonomia, an evolution-favoring book by his grandfather
Erasmus Darwin, as well as from encounters at Edinburgh with the
future London professor of anatomy Robert Grant, and from Lyell's
discussion of the thinking of Jean Baptiste de Lamarck) did not actu-
ally become an evolutionist on the voyage. But his encounter with
the different reptiles and birds on the Galapagos Archipelago shocked
him. How could one have different-but-similar forms on islands only
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The Origin of the Origin 3
a few miles apart? When, on his return to England, Darwin learned
that the birds were undoubtedly of different species, this was enough
to tip the balance. In the spring of 1 837, Charles Darwin slipped over
to transmutationism.
For eighteen months, until the end of September 1838, Darwin
worked hard looking for a cause of evolution. One suspects that
it was the ideal of Newton - much praised by the day's scientific
methodological gurus, especially John Herschel (1830) and William
Whewell (1837)- that spurred Darwin here. He wanted to find a force
for evolution akin to Newton's force of gravitational attraction. For
all that we have Darwin's detailed notebooks - perhaps because the
notebooks are so detailed - there has been debate about the exact
course of Darwin's thinking. Darwin himself always claimed that
he started with artificial selection, realizing that this was the way
in which breeders change their animals and plants. Then he started
to look for a natural equivalent, and this he found at the end of
September 1838 after he had read Thomas Robert Malthus's (1826)
treatise on population. More organisms are born than can survive
and reproduce. Those that get through will, on average, be different
from those that do not. And it is these differences - shaggier coats,
stronger legs, sharper eyes - that are crucial. Given enough time,
there will be overall change - descent with modification (what we
call "evolution") - and, moreover, this will be in the direction of
adaptive advantage. Shaggier coats keep sheep warm; stronger legs
let the wolf catch the deer; sharper eyes mean that the eagle can spot
the rabbit.
Through a careful reading of the notebooks that Darwin kept
while he was searching for his mechanism - a mechanism that, when
discovered, he clearly did think was akin to a Newtonian force -
some scholars have concluded that, although in his various sketches
and published versions of his theory Darwin does use artificial selec-
tion to lead into natural selection, it is unlikely that he really did
have the analogy in mind on his way to natural selection (Barrett
et al. 1987; Herbert 1971; Limoges 1970). He never really thought
that artificial selection could do the job, or at least that a natu-
ral equivalent would be sufficiently powerful to get full-blooded
change. Whether this interpretation is correct is something that
has been argued for some time now. My own feeling, looking at
some of the material that Darwin read during the crucial discovery
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4 MICHAEL RUSE
months - some material, incidentally, that not only drew attention
to artificial selection but also showed that one might expect a natural
equivalent, some material that Darwin highlighted particularly 1 - is
that he probably did have the analogy in mind. But I would agree
that he was more hesitant at the time than his confident later recol-
lections suggest (Ruse 1979).
Darwin did not at once write things up in any formal way. Indeed,
we have to work rather carefully through the notebooks to see that he
did appreciate the full worth of natural selection. (He did. Jottings
later in 1838 about human mental evolution put this fact beyond
doubt.) Moreover, it was to be another four years before he actu-
ally wrote out what was a thirty-five-page, penciled Sketch (as we
now call it) of his ideas (Darwin and Wallace 1958). This was then
extended in 1 844 to a 230-page Essay, which Darwin had fair-copied
by the local schoolmaster. It should be added that in his Autobiog-
raphy and elsewhere Darwin referred to 1838 as the point at which
he first thought up his species theory, and this may well be true,
although there seems to be no written record (nor indeed should
there necessarily be).
THE LONG DELAY
Darwin then put things on hold, and having written a letter to his
wife asking that in the event of his death she arrange that some
competent biologist bring the Essay to publication, he turned to a
massive eight-year-long study of barnacles (Darwin 1851a, b, 1854a,
b). It was not until around 1854 that he turned back to his evolution-
ary theory. It is clear that, by this time, word was starting to get out
that Darwin was an evolutionist - and he was in the habit of showing
bits of his writings to some of the young men he was encouraging
around him. His friends urged him to get back to the job and to go
public, lest he be scooped. Darwin therefore started to write a mas-
sive book about his theory. This was interrupted by the arrival, in
the early summer of 1858, of the essay by Alfred Russel Wallace,
1 Like most people who actually take seriously the task of uncovering Darwin's
thought processes, rather than triumphantly holding up something as evidence that
he was both unoriginal and a plagiarist, I do not in any sense suggest that Darwin
pinched natural selection from someone else, or that someone else should get the
real credit. None of his precursors were seeing natural selection as a mechanism of
evolutionary change, and some indeed denied that it could be.
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The Origin of the Origin 5
a naturalist and collector in the Malay Archipelago - the essay in
which Wallace captured almost exactly the ideas that Darwin had
discovered twenty years before.
Extracts of Darwin's writings along with Wallace's essay were at
once read at the next meeting of the Linnaean Society and published.
Despite stories about the ideas being disregarded, there was imme-
diate interest. Later in the summer, in his presidential address to the
British Association for the Advancement of Science, quite favourable
notice was made of the papers by Richard Owen (for all that he later
was cast as the Darth Vader of the Darwin Wars). By now, Darwin
had launched frenetically into the writing of what he wanted to call
an "abstract" of his thinking - a qualification that his publisher, John
Murray, wisely declined to accept for a work that in print extended
to 490 pages - and so finally On the Origin of Species by Means of
Natural Selection, or the Preservation of the Favoured Races in the
Struggle for Life, by Charles Darwin, M.A., appeared in November
1859.
There has been and still is considerable controversy over the rea-
sons why Darwin took so long to bring his theory into print. Recently
it has been suggested that this is a bit of a pseudo-problem, because
the delay was not really that long and because Darwin was, after
all, working away for much of the time on matters evolutionary
(Van Wyhe 2007). Those who apparently do not consider it a pseudo-
problem have included Thomas Henry Huxley (1893), who praised
Darwin for spending so much time on the barnacles and turning
himself into a real zoologist before he published; the late Dov Ospo-
vat (1981), who thought that Darwin moved from an ultra-natural
theological stance of seeing all adaptation as perfect to seeing it as
relative; and Robert J. Richards (1987), who thinks that Darwin was
so worried about the sterility of the hymenoptera (seemingly a coun-
terexample to a process that stresses reproduction) that it was not
until he had seen (in the early 1850s) that breeders could get desired
traits possessed by animals that do not breed (steers killed for food,
for instance) by going back to the family stock, that he realized that
something comparable could happen in nature and so felt free to get
cracking again on his theory.
For the record, I have been marked as one who thinks there was a
genuine delay, and I continue to think so (Ruse 1979). I am not too
bothered by the jump between 1839 an d 1842 or between 1842 and
1844. Darwin was working flat out on other projects, the geology
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6 MICHAEL RUSE
in particular. Most notably, making him into a household name,
Darwin wrote up his account of the trip around the world on the
Beagle, and what started as a formal report for the Admiralty turned
into one of the most popular of travel books at a time when society
just loved stories of exploration in distant and strange lands (Darwin
1839). Darwin was also newly married, moving to the house in Kent
(and having it extended), starting a family, and feeling sick. He had
more than enough on his plate at that time.
It is the gap between 1844 and 1858 that fascinates me. I am
happy to accept the bits and pieces of new information that come
into Darwin's thinking between 1844 and 1859. I have always been
impressed by the way that the barnacle work so convinced Darwin
of the variation that exists in all natural populations, something that
was crucial for a mechanism like natural selection. And let us not
forget the "principle of divergence," tied to the tree-of-life metaphor,
where Darwin saw that divergence is the way in which selection
maximizes the use that organisms can make of resources. Although
I think that in fact there are hints of it even in his notebooks of
the late 1830s, I accept fully that Darwin did not really realize the
problem and the solution until much later.
However, I have to say that none of this alone or in conjunction
really convinces me that this yields the solution. Two things always
strike me. First, Charles Darwin was always so ambitious. Never
let the friendly, warm, almost-casual man and his style deceive you.
At the beginning of her biography, Janet Browne speaks of the sliver
of ice in the heart of Charles Darwin. I have always thought that
this is so. He was not a nasty man in any way, but he did want
to make his mark as a scientist, and nothing was going to stand in
his way. The sickness was genuine, but he used it to advantage to
avoid boring jobs and people. His massive letter writing was sincere,
but again and again it was a medium through which Darwin could
get others to do jobs for him. And above all, he was going to get
into print. Just after the Beagle voyage, Darwin dashed up to Glen
Roy in Scotland to look at the parallel roads around the sides of the
valley, arguing that they were of marine origin. Unfortunately, the
subsequent paper in the Transactions of the Royal Society turned
out to be a bit of a disaster. Louis Agassiz was soon to point out that
the parallel roads were produced by a lake dammed by a glacier, not
by the now-receded sea. But the drive to get a paper on a hot topic
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The Origin of the Origin 7
into a prestigious journal certainly fits the pattern: a young man on
the make. I am not criticizing Darwin for this. If I did, I would have
to extend my comments to every successful scientist I have ever
met - in science as in love, being reticent gets you nowhere. So I just
cannot see Darwin, a man who knows he has solved the mystery of
organic origins, sitting on his hands for fifteen years.
My second point is that truly I cannot find all of that much differ-
ence between the Essay of 1844 and the Origin of 1859. I have long
argued - and continue to argue - that Darwin's theory is a very skilful
piece of work. It is, as he truly said, one long argument, not simply
one damn thing after another. I am convinced that the men influenc-
ing him on matters of methodology - William Whewell particularly,
but also John F. W. Herschel - taught Darwin that he had to find a
vera causa if he was to solve the organic origins problem. Darwin
knew that natural selection could do the trick. It was a force-like phe-
nomenon that explained adaptation, something that both scientists
and theologians (often one and the same person) were trumpeting.
But selection had to be set in the right justificatory framework. Sat-
isfying Herschel, who as an empiricist demanded direct or analogical
evidence, Darwin made much of the analogy between artificial and
natural selection - this is so whatever the role of artificial selection
in finding natural selection. Satisfying Whewell, who as a rational-
ist demanded that one's cause be at the apex of a consilience of
inductions (Whewell 1840, Herschel 1841) - the cause explains the
phenomena, the phenomena make reasonable the cause - the whole
of the second part of his theory is a trip through the sub-branches of
biology (paleontology, biogeography, systematics, anatomy, embry-
ology) as Darwin shows that selection provides explanations in such
areas and in turn is justified by such areas. The point I make here
is that this structure is in the Sketch, the Essay, and the Origin -
identical in form and presentation - and much of the evidence is just
the same. Even the sub-bits, like the introduction of sexual selection
along with natural selection, are the same.
ANSWERING THE QUESTION
So I still have the question of the delay. Why did Darwin not publish
the Essay back in 1844? My answer is twofold. First, he was scared.
Not of his wife or anything like that; and I doubt that being labeled
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8 MICHAEL RUSE
a materialist much bothered him. He came from a family and a set
(particularly connected with his brother Erasmus) where that was
not much of a taunt. In any case, Darwin was not a materialist.
He was a deist, and the various writings up to and including the
Origin make that very clear. (He even added additional references
to the Creator in later editions.) It was precisely the leaders of his
scientific set - those very men who had nurtured him and made his
early career possible - whom Darwin feared offending. 1 844 was the
year in which the notorious evolutionary work the Vestiges of the
Natural History of Creation was published, and the set went after
the work with a vengeance. Adam Sedgwick raged against it in the
Edinburgh Review - it was so vile it must have been written by a
woman, but surely no woman could pen such filthy muck. David
Brewster (physicist, biographer of Newton, and the inspiration for
the flowery passage with which Darwin ends the Origin) declaimed
against it in the North British Review. And Whewell thought it
so disgusting that he did not write against it but merely collected
selected passages from earlier writings for a little book - Indications
of the Creator. The first edition did not even mention the Vestiges
by name. I realize that the reception of Vestiges was by no means
uniformly negative - Tennyson, for instance, was to use its ideas to
finish In Memoriam - but for Darwin's group it was anathema. So
he knew that he had better stay silent.
The second reason is simply, as many have noted, that Darwin
just did not expect the delay to be so long. He set out on his barnacle
work thinking that it would take but a year, and it kept stretch-
ing on and on as he worked obsessively on the project. One year
stretched to eight. The species book - which in the light of the reac-
tions would need very careful documentation - did not get written.
I should say that I see here, balancing the ambition, the other side
of Darwin's character. He was selfish - call it self-centered if you
like - because, as a rich man who had been favoured in his youth, he
was accustomed to doing what he liked. He became obsessed with
a project, and nothing was going to stop him. To put the matter in
modern terms, he did not have to write research grants to show that
his work would cure cancer. He could just amuse himself, although
perhaps "amuse" is not the right word for someone who did work
so hard. I see this pattern again after the Origin. Why did Darwin
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The Origin of the Origin 9
not set up a selection lab at Down? He had the money, and there
were those who wanted to join him in doing just that. He could see
that selection was being downgraded by people like Huxley, but he
did not really fight back. Although Darwin did write the Variation
as an extension of the Origin and was sufficiently threatened by
Wallace's apostasy (arguing that human evolution demanded divine
intervention) that he felt compelled to write the Descent, scien-
tifically Darwin went on doing what he had always done, namely,
working away on projects - orchids (1862), climbing plants (1880),
earthworms (1881) - that caught his fancy.
A final comment. I see Darwin's sharing his evolutionary ideas
with others as part and parcel of this picture. He was not about
to share them with Sedgwick and Whewell - still the people who
really controlled science - but the younger members of the set had
long been discussing origins in a potentially naturalistic way. As
soon as he came back from the Beagle voyage, Darwin and Owen
began chewing the fat over such things. (Pertinently, Owen, the best
scientist of them all at this time, was probably well on the way
to some kind of Germanic evolutionism, but dared not publish his
work because he was so dependent on the established powers. He
did not dare accept a knighthood lest he appear too uppity.) Darwin
knew full well that when he did publish he would need supporters.
So it was quite natural to talk about these things with those who
were potential supporters and who, although they may have been
cowed by people like Whewell, certainly did not necessarily agree
with them.
THE ORIGIN AS ANACHRONISTIC
In a way, talking about the long delay is a bit like speculating on
whether Queen Victoria had sex with John Brown or whether the
heir to the throne was Jack the Ripper. Fun to do, but not really that
important, and probably ultimately futile. I would truly query only
whether it was not that important. If the Origin is fundamentally
different from the earlier versions, then it should be judged on its
own terms. I would hate, for instance, for someone to judge my
present taste in food and drink on my convictions as a small child in
postwar England. It would be baked beans and sliced white bread all
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10 MICHAEL RUSE
the way, washed down by a rather revolting fizzy concoction called
Vimto. But if the Origin is more a product of the late 1 830s and early
1840s, then we should judge it on those terms.
Let me make five points showing that such an approach pays
explanatory dividends. First, take the book's topic. Of course,
Charles Darwin was not the first to ask about organic origins. His
grandfather Erasmus had done so, for one. And in the 1840s and
1 850s people went on asking about the topic - Chambers (1844) in
the first decade and Herbert Spencer (1852) in the second. However,
I wonder if this was something on the front burner of the top profes-
sional biologists. Huxley was happy to get on board when the time
came, although it took through the 1860s for him to accept that the
fossil record showed evolution, and he never taught the topic in his
classes (Ruse 1996). For him, it was indeed the materialism and like
elements that were attractive. In the 1830s, however, Darwin's set
did rather obsess about the topic - usually very negatively! It was
described as the "mystery of mysteries" in a letter from Herschel to
Lyell - a letter that became very public thanks to its being reprinted
in Charles Babbage's Ninth Bridgewater Treatise (1838). My sense is
that Darwin brought the issues back into discussion - incidentally,
just at the time when Pasteur was showing the impossibility of spon-
taneous generation, and so in a way making the whole question of
origins a bit iffy.
Second, consider the style of the Origin. From the beginning,
everyone recognized that it was a remarkably easy read, especially
for a work that was doing so much and claiming to be scientific.
Richard Owen (i860) in his review in the Quarterly was quite nasty
about this, congratulating Darwin for writing in a way that we have
come to expect from the author of travel books and the like - the
implication being that, written as it was, this could not be a seri-
ous work. Darwin was certainly capable of writing stuff that could be
read only by the expert, if at all. Look at the barnacle monographs, for
example. But we must think of Darwin's patrons. He may not have
had to work, but there were those whose approbation he sought,
namely his father and his Uncle Josh (later his father-in-law). Dar-
win had a rather rocky start - second-rate at school, and dropping
out of medicine - and his father was rightly skeptical of his abilities
and his willingness to get down to things.
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The Origin of the Origin 1 1
After the Beagle voyage - even during the Beagle voyage - all
changed. The good reports came in, and then the wonderful travel
book showed what an all-around family credit he had become. This
was just the time when the Origin was being conceived, and, right
the way through, Darwin wrote for those who paid the bills, even
though by 1859 both father and uncle were dead. Owen was right. It
was an odd book for a professional scientist, but then Darwin was
an odd professional scientist, always with one foot in another world.
We see this in what I have referred to as his dual sides of ambition
and selfishness (or self-centeredness).
Third, there is the book's structure. People like Huxley, dominat-
ing biology by the time the Origin was published, could not have
cared less about that kind of methodology. Do your anatomy, draw
your analogies, trace your phylogenies. It was really all a bit non-
causal in its way - certainly noncausal in the sense of forces. Dar-
win of the 1830s thought otherwise. This was just the time when
men like Whewell were trying to define what it is to be a scientist,
and that is a major reason why they wrote their books showing the
nature of good science. It had to be causal, in a Newtonian sort of
way, and hence the debate over Newton's rather mysterious notion
of a vera causa. This was no abstract debate, nor was the differ-
ence insignificant between Herschel and his call for experience and
Whewell and his call for consilience. There was debate over geology,
with Herschel (1830) thinking Lyell did the right kind of stuff and
Whewell (1837) thinking that the catastrophists did the right kind
of stuff. Darwin, trained by catastrophists, converted to Lyell, was
very sensitive to these issues.
The same is true of another matter, namely, the debate over the
theory of light. By the 1830s, it was clear (thanks to the work of
people like Fresnel) that the particle theory of Newton was infe-
rior to the wave (or undulatory) theory of Huygens. Herschel (1827)
and Whewell (1837, 1840) battled over this, since no one actually
sees either particles or waves. Herschel tied himself into knots with
analogies to sound - tuning forks with sealing wax stuck on them
and that sort of thing. Whewell, somewhat smugly, simply identi-
fied the waves as the center of a consilience. Case closed. Darwin
was sensitive to this and in later life, likewise postulating an unseen
cause, came to use the wave theory as a good example for his own
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12 MICHAEL RUSE
theory (Darwin 1868). The point is that all of this went back to the
1830s, when Darwin was at his creative peak.
Fourth, take the obvious matter of function and final cause or
teleology (Ruse 2003). People like Huxley were just not interested
in these sorts of issues. For them, it was structure and form all the
way. In Darwin's language (which he took from others), they were
interested in Unity of Type, not Conditions of Existence. Huxley
declared openly that he was no naturalist. What turned him on were
the wonderful structures that were revealed through his work at the
dissecting table. The ends that features served were at best irrele-
vancies and at worst hindrances to finding true relationships. After
the Origin also, Huxley and his various scientific friends showed
much less interest in adaptation and more in formal issues. It was
really not until the twentieth century, after the work of the pop-
ulation geneticists, that function really began to ride again. This
was because it was only then that natural selection began to take
its place as the dominant mechanism of evolutionary change. And
why was there this connection between function and selection? Pre-
cisely because, as we have seen, natural selection is a mechanism
expressly intended to speak to function, and the reason for this is
that Darwin thought that (what John Maynard Smith called) "orga-
nized complexity" is the dominant feature of the living world. He
thought this because it was precisely what his teachers and senior
friends, like Sedgwick and Whewell, were telling him. In a way, by
the time the Origin appeared, it was already old-fashioned.
Fifth and finally, something to irritate my coeditor, there is the
matter of progress. Pretty much every Darwin scholar now agrees
that he accepted some form of biological progress. The question is:
what form of progress? I would argue that it is a form that makes
selection central, even though many think (with good reason) that
the relativity of selection drives a stake through the heart of progress
(Ruse 1996). Darwin saw organisms engaged in what today we call
"arms races," with adaptations getting better because of the competi-
tion with other lines of organisms. Ultimately, this all leads to intel-
ligence and the evolution of upper-class Englishmen. What makes
Darwin's treatment of progress so difficult to discern is that he often
seems opposed to the very notion. But what he is against is not
the very notion, but a kind of Germanic notion of inevitable upward
change for the better - a kind of progress through momentum, which
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The Origin of the Origin 1 3
many morphologists saw as analogous to the development of the
embryo from blob to fully complete organism.
Darwin was dead set against this. And why? Once again, because
such transcendentalism - such Naturphilosoph thinking - was hated
by Darwin's group in the 1830s. So he had to stay away from it.
It is this that makes the Origin very different from any of those
evolutionary (or quasi-evolutionary) tracts written in the Germanic
mode, whether it be Richard Owen's On the Nature of Limbs (1 849),
published ten years before the Origin, or Ernst Haeckel's Generelle
Morphologie (1866), published nearly ten years after the Origin. 2
CONCLUSION
The Origin of Species is a very great book and a very important book.
As I have tried to show, in respects it is also a very puzzling book.
I shall be disappointed if the contributors coming after me do not
challenge just about every substantive claim that I have made. That
is what makes the Origin, to this day, a very exciting book.
2 Robert J. Richards could not disagree more with this understanding of Darwin and
progress. For now, I will simply direct you to his writings where he makes his case -
Richards (1992, 2002, and 2004).
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MARK A. LARGENT
Darwin's Analogy between
Artificial and Natural Selection
in the Origin of Species
Darwin opened the Origin of Species precisely where he claimed
that his recognition of the engine of evolutionary change itself orig-
inated: with the transforming effects that breeders' selection of pre-
ferred characters had on their plants and animals. In the first chapter
of Origin, titled "Variation under Domestication," Darwin lays the
groundwork for his analogy between artificial and natural selection
by asserting that "the great power of this principle of selection is
not hypothetical/' and that through selection, either methodological
or unconscious, breeders fundamentally and permanently alter the
domesticated plants and animals in their charge [Origin, 30). Moti-
vated by their interest in enabling organisms that possess desired
traits to produce offspring, which would presumably share their par-
ents' preferred characteristics, breeders select favored individuals for
reproduction and destroy or otherwise discourage the perpetuation
of those that lack desired qualities. Darwin argued that the condi-
tions of life in the wild allow for a struggle for existence within
and between species that likewise tends to select for those char-
acteristics that permit survival and reproduction and against those
that tend to hinder organisms' opportunity to survive long enough to
reproduce and pass along their particular qualities. In later chapters -
in particular, Chapter 4, "Natural Selection" - these arguments coa-
lesce into his assertion that just as breeders could use selection to
change the characters of a particular breed, nature too could select
and thus modify a wild species.
This chapter will explore the specific role that the analogy
between artificial and natural selection played in Darwin's Origin of
Species. Was his analysis of artificial selection as significant for the
14
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Artificial and Natural Selection in the Origin 1 5
original formulation of his theory of evolution by natural selection
as he maintained in a letter to Alfred Russel Wallace in 1859 an d
again in his autobiography almost three decades later [More Letters,
1: 108; Letters, 67-8)? Or did Darwin come to appreciate the analogy
between artificial and natural selection only after he had conceived
of natural selection, which might lead one to believe that the anal-
ogy served only as a means to convince the reader of the reality of
evolution and natural selection? I will begin with a detailed descrip-
tion of Darwin's arguments in the first chapter of the Origin about
the efficacy of selection and the relationship between domesticated
and wild species, placing them in the context of claims made by
his contemporaries. I will then examine how he employs the anal-
ogy between artificial and natural selection to support his argument
about the reality of evolution and his theory of natural selection. In
offering the analogy, Darwin had to demonstrate the ability of artifi-
cial selection to alter domesticated organisms, and he had to demon-
strate a method by which nature could select for preferred charac-
teristics. I will conclude by addressing the question of how breeders'
work itself shaped the development of Darwin's theory. While he
later depicted the emergence of his theory and of the analogy itself
as a singular event, analyses over the last several decades suggest
that it arose slowly through a reciprocal relationship between his
theorizing and his evidence-gathering activities. Darwin and many
of the scholars who have described the genesis of his theory have
depicted it as springing to life between late September and early
October of 1838. I will ultimately argue that fully to appreciate the
role of the analogy between artificial and natural selection in the
production and presentation of Darwin's theory, we must consider
the two decades between the conception and reception of his theory
as one long period, condensed and presented in the Origin as simply
"one long argument" in a manner that reflects both the norms of the
philosophy of science of his day and the context of the book's author
and its audience [Origin, 459).
THE FIRST CHAPTER OF THE ORIGIN
Beginning with the empirical evidence available to him and to his
readers, Darwin explains that plants and animals that have been
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I 6 MARK A. LARGENT
under domestication for long periods of time show a broader range
of differences among varieties and subvarieties than do similar
organisms in the wild. Whereas various authors have disputed the
possible sources of these variations, Darwin explains that he is
"strongly inclined to suspect" that in both domesticated and wild
species variations originate with changes in the parents' "reproduc-
tive elements" that occur because of environmental forces [Origin,
8). This, combined with his assertion that confinement somehow
affects the reproductive system, explains why domesticated organ-
isms demonstrate greater variation, while animals in the wild show
less variation. The wider range of variation in domesticated organ-
isms is also evident in the production of a sport, which is "a new
and sometimes very different character from that of the rest of the
plant." Sports, Darwin explains, are more commonly found under
domestication than in nature, where they are "extremely rare" (Ori-
gin, 9-10).
The conditions of life, Darwin asserts, are of little importance
in producing variability in organisms directly. Plants are appar-
ently more directly influenced by conditions than are animals, but
both are capable of being slightly altered by their environments.
The various habits of individuals seem to have some influence in
shaping individuals' characters. For example, Darwin describes how
the bones of the domesticated duck's wings and legs have thick-
ened as compared to their wild counterparts. In similar fashion,
the udders of cows and goats that have been regularly milked for
generations have increased in size, and the ears of every domes-
ticated animal have grown droopy because of "the disuse of the
muscles of the ears, from the animals not being much alarmed by
danger" [Origin, 11). These sorts of examples, however, are rela-
tively uncommon, so he concludes that direct environmental effects
are not potent enough to explain the tremendous range of varia-
tion that he has recorded among various individual members of
a given species. Whereas Lamarck had seen in the conditions of
life the source for evolutionary change, Darwin rejects the claim
that environmental sources are directly capable of producing sig-
nificant new variations in an organism and concludes that they
must emerge through conditions affecting the sexual organs of
parents.
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Artificial and Natural Selection in the Origin 17
Darwin was not the first to address the potential analogy between
the manipulation of species by plant and animal breeders and the
transmutation of species in nature. Several earlier authors, includ-
ing Charles Lyell, John Sebright, and William Whewell, had dis-
cussed the potential relevance of evidence collected from domes-
ticated organisms to the debate over the mutability of species. A
consensus had emerged among these authors that breeding shed no
light on the potential mutability of wild plants and animals (Cornell,
307). Most significant was Lyell's treatment of the subject in the
second volume of Principles of Geology, which Darwin had received
when HMS Beagle had reached South America. Lyell had argued
that one could admit "a considerable degree of variability in the
specific character" of a breed without accepting the mutability of
species, which allowed him to explain how breeders could temporar-
ily alter or enhance preexisting characters in the organisms they bred
(Lyell, 2: 36). In the Origin, Darwin indirectly counters Lyell's claim
by arguing that alterations to domesticated organisms, which have
occurred for "an almost infinite number of generations," indicate
that large modifications can become permanent, despite the occa-
sional reversion [Origin 15). He then introduces a different kind of
selection, natural selection, to explain how new traits could be made
permanent in the wild.
The basis for Darwin's analogy between artificial and natural
selection was predicated on two related assertions: first, that breed-
ers did permanently alter breeds though selection and, second,
that they brought about modifications that had not existed in the
domesticated organisms' wild ancestors. For Darwin to support his
eventual argument about evolution by natural selection, he would
have to demonstrate the truth of both of these claims.
7s Selection Efficacious!
Darwin relied on the tremendous variety found among domesti-
cated pigeons, more than any other domesticated plant or animal, to
demonstrate breeders' ability to produce distinct varieties by manip-
ulating the variations within a given species. In letters to his cousin,
William Darwin Fox, he indicated that he had found Fox's "careful
work at pigeons really invaluable." It had allowed him to "trace the
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I 8 MARK A. LARGENT
gradual changes in the breeds of pigeons" and was "extraordinarily
useful" [Letters, i: 84; Secord, 183). Domesticated pigeons revealed
to Darwin that the diversity of breeds humans had produced from
limited wild stock was "something astonishing" [Origin, 19). Dar-
win himself experimented with varietal crosses in order to show that
offspring in the third generation often reverted to colors character-
istic of the rock pigeon. This and other kinds of evidence indicated
to Darwin that domestic selection could introduce new varieties
that were permanent modifications of an aboriginal stock. For the
oppositional claim that domestic breeds descended from similar wild
organisms to hold true, he explained, the supposed aboriginal stocks
must either still have existed in the countries where they were origi-
nally domesticated and not yet have been found by ornithologists, or
they must have gone extinct in the wild. Neither possibility seemed
likely.
Darwin formally introduces the concept of selection in the Origin
by offering an explanation of how breeders could have produced the
current domestic varieties from one or several allied wild species.
He states that one of the most remarkable features of domesticated
plants and animals is that their adaptations are not for their own
good, but rather for man's use or fancy. How do humans manipulate
wild species in order to produce the desired domesticated plants and
animals? Darwin explains, "The key is man's power of accumula-
tive selection: nature gives successive variations; man adds them up
in certain directions useful to him. In this sense he may be said to
make for himself useful breeds" [Origin, 30). The differences from
which the breeder selects are often "absolutely unappreciable" to
the "uneducated eye," so a breeder has to be gifted with a natural
capacity and years of practice to identify such minute differences
[Origin, 32). Darwin's analogy between artificial selection and nat-
ural selection is also an analogy between the practiced eye of the
breeder and nature itself. As James Secord explains: "By demonstrat-
ing the existence of the smallest differences in creatures that looked
identical to the untrained observer, he hoped to show his readers
that wild nature could be seen with the practiced eye of the pigeon
fancier" (Secord, 164).
Darwin suggests that one might object to his claims about the
efficacy of breeders' selection, which he terms "methodological
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Artificial and Natural Selection in the Origin 19
selection/' by arguing that it had been practiced only for about
seventy-five years. However, he responds, the potential effects of
selection are hardly a modern discovery; "the inheritance of good
and bad qualities is so obvious" that it most assuredly influences
the actions of even the "lowest savages" [Origin, 34). Nonetheless,
there is arguably a difference between the work of modern method-
ological selection and earlier breeding efforts, so Darwin introduces
the concept of unconscious selection, which results from "every
one trying to possess and breed from the best individual animals"
[Origin, 34). Using the example of the many varieties of dogs that
have descended from the spaniel, including setters and the English
pointer, he argues that changes in the animals have "been effected
unconsciously and gradually, and yet so effectually that, though the
old Spanish pointer certainly came from Spain," there is no native
dog in Spain that is anything like the English pointer [Origin, 35).
Darwin makes similar arguments using horses, pigeons, and sheep as
examples. Unconscious selection could also occur, he later argues,
when "many men, without intending to collectively alter a breed
toward a particular ideal, have a nearly common standard of perfec-
tion, and all try to get and breed from the best animals" [Origin, 102).
Darwin's distinction between methodological and unconscious
selection includes a relatively low estimation of the apparent differ-
ence in efficacy between the two. This may have been an argument
against those who would have dismissed the power of selection by
claiming that humans had practiced it rigorously for less than a
century. One might also argue, as some scholars have, that Darwin
underestimated the differences between methodological and uncon-
scious selection in order to avoid the accusation that he was pro-
moting the concept of design in nature by asserting that nature,
like the breeder, exerted a will in selecting for particular character-
istics. When he develops the analogy between artificial and natural
selection later in the Origin, Darwin downplays the overall effects of
man's selection as compared to the selective influence of the struggle
for existence, and judges that nature is ultimately more successful in
selecting organisms: "How fleeting are the wishes and efforts of man!
how short his time! and consequently how poor will his products be,
compared with those accumulated by nature during whole geolog-
ical periods." Darwin likewise describes how organisms subjected
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20 MARK A. LARGENT
to natural selection are, as a result, "truer" in character and thus
plainly bear "the stamp of far higher workmanship" [Origin, 84).
John Angus Campbell has argued that Darwin did this in order to
take advantage of mid- Victorian readers' affinity for the language of
design (Campbell, 361). Take, for example his explanation of how
nature selects: "It may be said that natural selection is daily and
hourly scrutinizing, throughout the world, every variation, even the
slightest; rejecting that which is bad, preserving and adding up all
that is good; silently and insensibly working" [Origin, 84).
An even stronger argument to explain Darwin's motive for his
assertion that methodological selection is only slightly more effica-
cious than unconscious selection contends that Darwin discounted
their differences in order to effectively claim that unconscious selec-
tion is merely a type of natural selection. We see evidence for this
when, foreshadowing his ultimate claim that nature itself selects,
Darwin describes a type of unconscious selection that occurs in
times of great stress: Even "savages so barbarous as never to think of
the inherited character of the offspring of their domesticated ani-
mals" still preserve their most useful animals even in times of
famine [Origin, 36-7). Darwin also introduces the concept of the
struggle for survival, which readers would soon learn is vital to his
theory of evolution by natural selection, by discussing the special
pressures on the domesticated animals kept by uncivilized man.
Unlike the modern breeders' animals, those raised by uncivilized
man would have had to struggle for their own food, at least during
certain seasons. This struggle would lead to a kind of "natural selec-
tion," which Darwin places inside quotation marks [Origin, 38). He
views the animals kept by uncivilized man as existing in conditions
somewhere between the wild and those offered by modern breeders.
In this interpretation, human intention played no essential role; to
convince his readers of the efficacy of unconscious selection would
be to get them simultaneously to admit to the reality of natural
selection.
Did Domesticated Characters Exist in Wild Ancestors!
In the case of those species that have been domesticated for the
longest periods of time, Darwin does not believe it is possible to
come to any definite conclusion about whether they descended from
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Artificial and Natural Selection in the Origin 21
one or from several parent species. He nonetheless argues that the
broad range of domesticated varieties has derived from a very few
wild ancestors, which have demonstrated far less variation than did
their domesticated progeny. Darwin claims to have once believed,
as did most every breeder and many naturalists of his day, that there
were multiple original breeds of wild animals that exhibited the
same range of variation found in current domesticated animals. He
had "never met a pigeon, or poultry, or duck, or rabbit fancier, who
was not fully convinced that each main breed was descended from a
distinct species." It was sensible for them to believe this, he explains,
as "from long-continued study they are strongly impressed with the
differences between the several races." But they refuse to "sum up in
their minds slight differences accumulated during many successive
generations" [Origin, 29).
In drawing an analogy between the alleged efficacy of the breed-
ers' selection and selection in nature, Darwin confronted the well-
established claims that breeders could do little more than sharpen or
emphasize characters already in existence among wild species and
that they could not make permanent any alterations they achieved
through selective breeding. For example, in the second volume of
Principles of Geology, Lyell had agreed with Frederic Cuvier that
domesticated animals' "domestic qualities" were "modifications of
instincts. . .implanted in them in a state of nature" (Lyell, 2: 41).
In cases in which these animals appeared to have acquired "attain-
ments foreign to their natural habits and faculties," he asserted that
such habits were never transmitted from one generation to the next
(Lyell, 2: 42). The apparently rapid changes that breeders were able to
achieve among their animals occurred only in the first generation or
two, and they were lost once animals returned to a wild state. "Every
husbandman and gardener," he wrote, was aware that experiments to
acclimatize species substantially and permanently to environments
to which they were not suited were doomed to failure (Lyell, 2: 38).
Likewise, among the breeders Darwin consulted during the 1850s,
most believed that the current variety of domesticated plants and
animals mirrored a preexisting range of variation of original wild
stocks (Eaton 1851; Eaton 1858; Ruse 1975a, 344-349; Secord, 169).
Darwin went to great pains to undermine the breeders' notion that
domestic stocks had multiple, similar wild ancestors and to encour-
age readers to accept the idea that fundamentally new variations
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22 MARK A. LARGENT
could be derived from existing stocks. As Secord concluded, "Dar-
win's discussion of the pigeon was almost entirely an attempt to
prove conclusively . . . that the incredible diversity of the domestic
pigeons was indeed countered by the unity of their origin" (Secord,
179)-
If existing domesticated varieties were mere reflections of their
wild ancestors, Darwin's analogy between artificial and natural
selection would have failed because selection would not have
brought about fundamentally new characters. It was therefore vital
for Darwin to demonstrate the contrary position, and he argues that
his interpretation of the origin of apparently unique characters found
in domesticated pigeons is a better explanation than other potential
accounts because it is simpler. He explains that it is rare to find in
nature the sort of structures that exist in the domesticated species
of pigeons, and in order for this to occur, "half-civilized man" would
have had to have thoroughly domesticated several species of wild
pigeons and, by chance or by intention, have picked several extraor-
dinary abnormal species, all of which then went extinct. "So many
strange contingencies," he concludes, "seem to me improbable in the
highest degree" [Origin, 24). Likewise, taking into consideration the
coloring of pigeons, he finds incredible diversity. If all the domes-
tic breeds descended from similarly diverse wild species, it would
be easy to assume that humans had had nothing to do with pro-
ducing the diversity of coloring. However, doing so leaves us with
two "highly improbable suppositions:" first, that all the "several
imagined aboriginal stocks were coloured and marked like the rock
pigeon," and second, that domesticated species had simply reverted
to the very same colors and markings. Or that each of the domesti-
cated species has been crossed with the rock pigeon and reverted to
the characters of the non-rock pigeon parent, and Darwin explains
that there is no evidence that offspring reverted to the characters of
only one parent [Origin, 25-6). All of the competing explanations
that Darwin offers require extraordinary events or circumstances, so
his claim that new characters arose via selection appears the most
viable given William Whewell's claims that the simpler and more
harmonious explanations tend to be true. In his Philosophy of the
Inductive Sciences, Whewell had argued that the ability to explain
a wide range of phenomena with fewer and simpler arguments was
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Artificial and Natural Selection in the Origin 23
the mark of a good theory. In true theories, he explained, "all the
additional suppositions tend to simplicity and harmony; the new
suppositions resolve themselves into the old ones, or at least require
only some easy modification of the hypothesis first assumed." In
false theories, by contrast, "the new suppositions are something
altogether additional" (Whewell, 2: 68-9). Darwin was well aware
of Whewell's work and genuinely enthusiastic about it (Ruse 1975c,
166).
Darwin concludes the first chapter of the Origin by identifying a
number of factors that aid or hinder the power of breeders' selective
efforts to alter breeds. A high degree of variability is favorable, and
large numbers of kept individuals increase the chance that preferred
qualities will appear, while low numbers encourage breeders to per-
petuate every individual and effectively prevent selection. Those
plants and animals that are especially useful compel breeders to give
each individual the closest attention as they search for the slight-
est favorable deviation in qualities or structure. Preventing crosses
between emerging varieties encourages divergence, so geographical
separation of varieties by the enclosure of land is a significant factor
in allowing the selection of traits to generate fundamentally new
breeds. He also explains why, in contrast to organisms like pigeons,
certain breeds of domestic animals have not developed new varieties.
In the case of cats, he asserts, there is great difficulty in controlling
their pairing. With donkeys, too few have been kept and those by
poor people, so little attention has been paid to their breeding. Pea-
cocks are not easily reared and large stocks are not kept, and geese
are valuable for only two purposes, food and feathers, so there is lit-
tle compulsion to produce new varieties and thus little attention is
paid to their selection. Darwin concludes: "Over all these causes of
Change I am convinced that the accumulative action of Selection,
whether applied methodically and more quickly, or unconsciously
and more slowly, but more efficiently, is by far the predominant
Power" [Origin, 42-3).
Darwin's discussion in the first chapter of the Origin of the effi-
cacy of selection in the hands of plant and animal breeders provides
the basis for the analogy he draws between artificial and natural
selection in the fourth chapter. He begins Chapter 4, titled "Natu-
ral Selection," by pointedly asking, "Can the principle of selection,
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24 MARK A. LARGENT
which we have seen is so potent in the hands of man, apply in
nature?" [Origin, 80). Keeping in mind the apparently endless num-
ber of potential variations in all organisms, domesticated or wild,
the apparent plasticity of organisms, and the powerful effects of the
struggle for life, he asserts that the realities and particularities of
life in the state of nature differentially affect plants and animals.
Just as certain variations in domesticated organisms are useful in
some way to humans, some traits must be "useful in some way to
each being in the great and complex battle of life" [Origin, 80). He
concludes, "it would be a most extraordinary fact, if no variation
ever had occurred useful to each being's welfare," given the fact that
humans have found so many variations in plants and animals useful
to them [Origin, 127).
THE ROLE OF THE ANALOGY BETWEEN ARTIFICIAL
AND NATURAL SELECTION IN DARWIN'S THEORY
From the examination of Darwin's notebooks, letters, and the vari-
ous editions of his Origin of Species by science studies scholars, we
have learned a great deal about the process by which Darwin devel-
oped his theory and the manner in which he presented it to profes-
sional and public audiences. Of particular interest to many scholars
has been the question of the role that his analogy between artificial
and natural selection played in the actual development of his theory.
Darwin claimed that he had conceived of the mechanism of natural
selection only after coming to appreciate the significance of selec-
tion in the work of plant and animal breeders. Both in an 1859 letter
to Wallace and in his autobiography, Darwin affirmed this scenario:
"I came to the conclusion that selection was the principle cause of
change from the study of domesticated productions; and then, read-
ing Malthus, I saw at once how to apply this principle" [More Let-
ters, 1: 108; Autography, 67-8). However, on examining his private
notebooks, some have argued that in fact Darwin adopted the poten-
tial analogy only after he had conceived of natural selection (Young,
109-45; Vorzimmer, 225-59). Several scholars have argued that, con-
trary to the actual structure of his argument in Origin as well as his
later claims, Darwin had not fully developed his understanding of
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Artificial and Natural Selection in the Origin 25
the power of breeders' selective activities until after he had estab-
lished in his mind his explanation of the process of natural selection.
Sandra Herbert, for example, asserts that Darwin does not seem to
have held a "sufficiently unambiguous notion of artificial selection"
that would have enabled him to anticipate finding "a similar pro-
cess at work in untended nature." She concludes, "the discovery of
natural selection made the domestic analogy much more clear to
Darwin than it had been before" (Herbert, 212-13). A recognition of
the vital role that Darwin's description of pigeon breeding played in
the first chapter combined with Secord's description of how Darwin
immersed himself in the world of English pigeon fanciers from 1855
until he began writing the Origin in the summer of 1858 likewise
suggests that his reliance on the analogy between artificial and nat-
ural selection emerged in concert with, rather than subsequent to,
his description of the mechanism of natural selection (Secord, 163-
4). Even taking into account earlier statements by Darwin, such as
the passage in his 1844 letter to }. D. Hooker in which he discounts
proposed evolutionary mechanisms because their authors have not
"approached the subject on the side of variation under domestica-
tion," it appears that Darwin increasingly explored and emphasized
the analogy after his 1838 reading of Malthus [Letters, 2: 29; Evans,
114). Other scholars, such as Limoges (1970) and Kohn (1980), like-
wise dispute Darwin's later claim that his full appreciation of the
efficacy of artificial selection led him to perceive in Malthus's pas-
sages a comparable mode of selection in nature.
Further evidence that undermines Darwin's claim about the pri-
ority of artificial selection in the formulation of his theory of natural
selection can be found in a document he published several months
after reading the Principles of Population. The "printed enquiries"
that Darwin mentions in his autobiography that he used to col-
lect "facts on a wholesale scale" consisted of an eight-page quarto
pamphlet titled "Questions about the Breeding of Animals," which
contained twenty-one numbered paragraphs containing forty-eight
questions (Vorzimmer, 269-81 ). Darwin self -published the pamphlet
in the spring of 1839 an d presumably sent it to breeders to collect
information about their methods. His inquiry, as Peter Vorzimmer
explains, consisted almost exclusively of leading questions. "That
is, they are framed in such a way as to elicit specific responses which
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26 MARK A. LARGENT
may or may not confirm an existing hypothesis. This is borne out
by the conditional interrogative ["If this . . . will this ...?") syntactic
arrangement of nearly all the queries" (Vorzimmer, 281). It is there-
fore apparent that Darwin had in mind a specific hypothesis when
he published the pamphlet. Knowing the specific questions Darwin
asked breeders, we can see how he integrated their answers into the
first chapter of the Origin. For example, the answers apparently given
to question #1 9 - "Can you give the history of the production in any
country of any new but now permanent variety, in quadrupeds or
birds, which was not simply intermediate between two established
kinds?" - were borne out in Darwin's assertion in the first chapter
of the Origin that "the possibility of making distinct races by cross-
ing has been greatly exaggerated" and that "a breed intermediate
between two very distinct breeds could not be got without extreme
care and long-continued selection; nor can I find a single case on
record of a permanent race having been thus formed" [Origin, 20).
Michael Ruse (1975a) has summarized and commented upon
claims, principally those by Herbert, that Darwin misrepresented
the significance of his examination of domesticated plants and ani-
mals in the development of his theory of evolution by natural selec-
tion. After presenting Darwin's assertions about the significance of
his study of domesticated plants and animals to the development
of his theory of natural selection, Ruse reviews the claims made
by more recent commentators and initially concludes that they are
essentially correct. "The artificial selection analogy did not have a
crucial role in Darwin's discovery of natural selection as a cause of
evolutionary change. It was only after he had grasped this later con-
cept that he came to stress the analogy" (Ruse 1975a, 344). However,
he likewise identifies one significant problem with this conclusion:
it ignores the influence of two pamphlets written by breeders, works
that Darwin had carefully examined about six months before he read
Malthus's Essay on Population. These pamphlets were John Wilkin-
son's "Remarks on the Improvement of Cattle" (1820) and John
Sebright's "The Art of Improving the Breeds of Domestic Animals"
(1809).
Ultimately, Ruse seeks to reconcile Darwin's claims about the
development of his theory with scholarship that disputes the role of
artificial selection in the evolution of Darwin's thought by weaving
"a fabric which makes better sense of what Darwin himself said
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Artificial and Natural Selection in the Origin 27
about his path of discovery, while not denying the actual things
Darwin wrote in his notebooks at the time of the discovery" (Ruse
1975a). He does this by depicting the emergence of Darwin's theory
as the result of his simultaneous appreciation of both the struggle for
existence and the analogy between artificial and natural selection,
all of which came about when he "read for amusement" Malthus's
Essay on Population [Autobiography, 68). Darwin had come across
depictions of what he eventually called the "struggle for existence"
as well as an analogy between the actions of breeders and those
of nature in his earlier readings, the former in Lyell's Principles of
Geology and the latter both in Sebright's 1 809 "The Art of Improving
the Breeds of Domestic Animals" and in Lamarck's work, which
Lyell had disputed. Later scholars who have examined the genesis
of Darwin's analogy between artificial and natural selection, such
as L. T. Evans, have described how these works "stimulated him
to seek a mechanism in nature equivalent to the sustained gradual
picking employed by breeders" (Evans, 124).
How are we to answer the question of the relationship between
Darwin's use of the analogy between natural selection and selection
as it was performed by breeders (and thoroughly described in the first
chapter of the Origin) and the actual impact of his study of the work
of breeders on his own development of the theory of evolution by nat-
ural selection? Did Darwin, either intentionally or unintentionally,
misrepresent the path he had followed in generating his theory of
evolution by natural selection? Are the historians and philosophers
who, over a century later, dispute his recollection of the emergence
of his theory correct in their assertions that he did not first compre-
hend the efficacy of artificial selection and then discover the engine
of natural selection in the struggle for existence? I conclude that
while both Darwin and his analysts are prone to depict the theory of
evolution by natural selection as having sprung to life one evening
in the fall of 1838, it was in fact merely conceived the evening that
Darwin amused himself by reading Malthus's Essay on Population.
It took twenty-one years of gestation - which included at least four
years of labor during which Darwin "entered with enthusiasm on
forays into the world of the English pigeon fanciers through printed
inquiries and the study of breeders' writings," the inhibiting influ-
ence of Chambers' 1 844 Vestiges of the Natural History of Creation,
and a final push motivated in part by a letter from Alfred Russel
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28 MARK A. LARGENT
Wallace - before Darwin's theory of evolution by natural selection
finally emerged into the public's view (Secord, 164; Chambers; More
Letters, 1 : 118). Imagining Darwin's theory as coming into existence
with his instant appreciation of Malthus's description of the struggle
for existence in the preexisting context of his awareness of the effi-
cacy of artificial selection leads us to debate awkward and often
uninformative questions about chronology. Shifting our frame of
reference from one evening in 1838 to nearly two decades of intel-
lectual development and evidence gathering allows Darwin the time
to find support for his theory recognize patterns, and develop strate-
gies with which to present his argument to both professional and lay
audiences.
If, in fact, the emergence of Darwin's theory of evolution by natu-
ral selection was a process that took many years, why did he describe
it in letters to Wallace and in his autobiography as having come to
him all at once upon reading Malthus ? The answer may well rest not,
as philosophers have assumed, within Darwin's argument itself, but
rather within the larger context of his audience. That is, while I
claim that Darwin's production of his theory was an iterative pro-
cess during which he took years to consider evidence and sharpen
the argument, his presentation of the theory in the Origin was nec-
essarily a single, linear explanation of it. "One long argument," as
he called it at the end of the book and as subsequent scholars have
emphasized [Origin, 459; Mayr). He thus framed his argument in the
form of what Campbell has depicted as a set of stairs, with the first
four chapters leading readers from artificial selection, to variation
in nature, to the struggle for existence, to natural selection (Camp-
bell 2003, 203-7). Doing so led his readers from the apparent effects
of breeders' selection, via analogy, to nature's selective influence.
It reflected Bacon's advice to scientific authors that one ought to
recapitulate the order of discovery in order to give readers a sense
of discovering the argument's points independently (Campbell 2003,
361). Both the Origin and Darwin's later depiction of the emergence
of his theory condensed its development into a series of linear events.
Thus, the book began precisely where Darwin would later assert that
his recognition of the engine of evolutionary change originated: with
the apparent effects that breeders' selection of preferable characters
had on their plants and animals, and its possible analog in nature.
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Artificial and Natural Selection in the Origin 29
ACKNOWLEDGMENTS
The author wishes to thank Michael Ruse, Robert Richards, Paul
Farber, John P. Jackson, David Depew, and Chris Foley for their com-
ments and suggestions.
Cambridge Collections Online © Cambridge University Press, 2009
ROBERT OLBY
3 Variation and Inheritance
Darwin signaled the preeminent importance of natural selection
in both the title and subtitle of his book the Origin of Species. But
without variation as the raw material upon which selection can act
and inheritance as the means for preserving favorable variations in
the future, natural selection would not lead to the genesis of new
species. How, then, did Darwin present these two topics in the Ori-
gin 2 . Answering this question will require textual analysis of the first
edition of the Origin, including some reference to changes in later
editions, and a little indulgence in some more speculative discussion
of the subject. The chapter will address the following questions:
i . Why did Darwin privilege variation in 1859?
2. Why did he hold that changes in the conditions of life provide
the chief raw material for evolution?
3. Had Darwin known of Mendel's critique of his work, how
might the sixth edition of the Origin have differed from what
was published?
INTRODUCTION
To the contemporary reader with some knowledge of modern biol-
ogy, the crucial importance of heritable variation to the theory of
species transmutation has no need of justification. It is obvious.
Yet Darwin's manner of presenting it and the theoretical stance he
adopted must seem strange, even extraordinary.
As to his manner, Darwin assumes a strong inductive style: he
repeatedly refers to facts, "copious details" of them [Origin, 8), "a
30
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Variation and Inheritance 3 1
long list" on this, "numerous instances" of that [Origin, 9), "a long
catalogue of facts" on something else [Origin, 131), none of which
he judged he had the space to detail. But repeatedly he tells us how
these facts have convinced him of their portent. Many data he finds
"perplexing," others "doubtful." There are doctrines that he "cannot
doubt" [Origin, 17), others that he cannot "believe" [Origin, 18), yet
others that drive us to "conclude ..." [Origin, 7). This very personal
style is also couched in slippery language with double negatives, and
qualifiers like: "It seems to me not improbable that. . . " [Origin,
1 5 ). As the physicist William Hopkins commented, in reviewing the
Origin, where Newton demonstrated, Darwin asserted (Hull 1973,
239-40). The zoologist Richard Owen likewise remarked that to be
served up an "expression of a belief, where one looks for a demon-
stration, is simply provoking" (Hull 1973, 209). Today we can look
in vain for a rigorously controlled experiment on variation or hered-
ity yielding numerical data sufficient to convince us. We have to be
satisfied with the occasional crucial experiment that he suggests but
does not carry out. Little words like "perhaps," "probable," and "pos-
sible" repeated again and again may carry conviction. But the critic
Fleeming Jenkin complained about "all these maybe's happening on
an enormous scale, in order that we may believe the final Darwinian
'maybe', as to the origin of species." And he concluded: "There is
little direct evidence that any of these maybe's actually have been"
(Hull 1973, 339). Over a century later, Gertrude Himmelfarb took up
this theme, remarking: "As possibilities were promoted into prob-
abilities, and probabilities into certainties, so ignorance itself was
raised to a position only once removed from certain knowledge"
(Himmelfarb, 335, cited in Gale, 157).
We know, of course, that the absence of fuller empirical data was
due to the rush with which the book was prepared following Alfred
Russel Wallace's letter of June 1858. The manuscript of Natural
Selection, already more than 225,000 words long, had to be shaved
down. Only one half of the text in the Origin can be identified with
passages in Natural Selection. The two chapters on Variation under
Domestication in Natural Selection were reduced to one in the Ori-
gin [Species Book, 10-14).
The tone, bordering on pleading for the reader's confidence in
his claims regarding variation, had much to do, no doubt, with this
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32 ROBERT OLBY
enforced absence of so much of his data, but also, more importantly,
with his prior knowledge of the disinclination of a number of his
friends (not to mention his critics) to accept his claims regarding
variation - Joseph Hooker, Asa Gray, Thomas Henry Huxley, and
Charles Lyell, in particular.
PRIORITIZING VARIATION
Darwin devoted Chapters i, 2, and 5 of the Origin to variation.
"Variation under Domestication" comes first, followed by "Varia-
tion under Nature." After moving on to the struggle for existence
(p. 60) and natural selection (p. 80), we are back to variation under
"Laws of Variation" (p. 131). Inheritance is not given a chapter to
itself, nor is the subject ever discussed fully in its own right else-
where in the Origin, but the inheritance of variations is briefly dis-
cussed in all three of the variation chapters 1 . No other topic in the
Origin was given as much stand-alone coverage as variation. Inher-
itance, by contrast, did not receive separate treatment until 1868
in his great two-volume work The Variation of Animals and Plants
under Domestication. Inheritance never achieved that status in later
editions of the Origin.
Darwin explained in his introduction to the Origin how, when he
began his transmutation studies and was seeking for the "means of
modification" of species, he judged that "a careful study of domes-
ticated animals and cultivated plants would offer the best chance
of making out this obscure problem" [Origin, 4). In addition to the
analogy he intended to draw between the breeder's practice of selec-
tion and nature's, such a study would show that "a large amount
of hereditary modification is at least possible" [Origin, 4). As Jon
Hodge has pointed out, the variation chapters illustrate Darwin's
attempt to establish the existence, competence, and responsibility
of variation as a vera causa (true cause) in his theory of the origin of
species (Hodge 1977).
Inheritance was at the time both a popular and a problematic sub-
ject. Henry Thomas Buckle's History of Civilisation in England,
1 It was somewhat misleading for Vorzimmer to state that inheritance "was confined
to a single chapter" in the Origin (Vorzimmer, 21).
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Variation and Inheritance 3 3
volume 1, came out in 1857. There Buckle castigated the many
authors writing on the subject of man's hereditary qualities:
The way in which they are commonly proved is in the highest degree illog-
ical; the usual course being for writers to collect instances of some mental
peculiarity found in a parent and in his child, and then to infer that the pecu-
liarity was bequeathed. By this mode of reasoning we might demonstrate
any proposition. (Buckle, 1: 159)
He was attacking the medical profession, the source of claims for an
hereditary "diathesis" or constitutional predisposition of people to
gout, asthma, adverse reaction to coffee, and so many other afflic-
tions and aberrant behaviors. Darwin needed inheritance, and he
bought into the diathesis craze, but he also had need of a disrupt-
ing force that would overcome inheritance to yield variations. This
brings us to the conditions of life.
CHANGES IN THE CONDITIONS OF LIFE
Already on the opening page of Chapter 1 we find the following:
When we reflect on the vast diversity of the plants and animals which
have been cultivated, and which have varied during all ages under the most
different climates and treatments, I think we are driven to conclude that this
greater variability is simply due to our domestic productions having been
raised under conditions of life not so uniform as, and somewhat different
from, those to which the parent-species have been exposed under nature.
{Origin, 7)
Brought up in Shropshire, and since 1 841 living in Kent, Darwin was
well situated to appreciate this remarkable variability. For England,
despite its industrial development, was still a landed society where
the wealthy could easily live in a rural setting. It was, too, the fore-
most country in agriculture and horticulture, its plant and animal
breeders having won international renown.
The circumstances that he judged significant for variation were
those of changes in the "conditions of life." This choice among the
possible causes of variation resulted neither from his intense study
of the works of the German hybridists Joseph Kolreuter and Carl von
Gartner, nor from his study of the British hybridists - the Hon. and
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34 ROBERT OLBY
Rev. Dean Herbert, Thomas Andrew Knight, and others - but from
pondering the "favourable circumstances" for variation, namely, the
domestication of animals and the cultivation of plants.
Alongside the variability of species under domestication, Darwin
was also impressed by the evidence of decreased fertility, often
amounting to complete sterility. A frequent visitor to the Zoological
Gardens in London, Darwin requested data on the reproductive suc-
cess achieved by the more exotic inmates [Correspondence, 3 : 404-5;
Desmond 1985). The many failures reported to him convinced him
that "[njothing is more easy than to tame an animal, and few things
more difficult than to get it to breed freely under confinement, even
in the many cases when the male and female unite." This was not
merely a matter of "vitiated instincts," he wrote, for "how many
cultivated plants display the utmost vigour and yet rarely or never
seed!" [Origin, 8). Surely it was the changed conditions of domesti-
cation and cultivation that were disturbing the reproductive systems
of these organisms, yielding degrees of reduced fertility, even utter
sterility.
Professor Richard Owen, in his review of the Origin, was quite
unconvinced. He appealed to the recent experience at London's Zoo-
logical Gardens, where the young pair of giraffes introduced in 1838
had, since attaining maturity, produced nine offspring. Other suc-
cess stories included the breeding pair of hippopotami at the Jardin
des Plantes in Paris (Hull, 208). Indeed, Darwin himself admitted
in the Origin that tropical carnivores, as well as rabbits and ferrets
kept in most unnatural conditions (i.e., in hutches), reproduce freely
[Origin, 9). Here, he admitted, their reproductive systems were not
affected. He cited further striking examples of domestic fecundity in
1868 (Darwin 1868, 2: 135).
Among animals subjected to confinement, Darwin noted that
the reproductive systems of some still functioned, yet they acted
"not quite regularly." So they produced "offspring not perfectly
like their parents," that is, they showed variability [Origin, 9). This
reminded him of the discovery by the French comparative anatomist
Geoffroy St. Hilaire that "unnatural treatment" of embryos caused
the production of "monstrosities." These, Darwin held, "cannot
be distinguished by any clear line from mere variations" [Origin,
8). Maybe domestication is a very mild form of "unnatural treat-
ment." That being the case, he "strongly inclined to suspect that
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Variation and Inheritance 3 5
the most frequent cause of variability may be attributed to the male
and female reproductive elements having been affected prior to the
act of conception" [Origin, 8). Thus arose Darwin's hypothesis of
the "indirect action of the environment" - the assumption that in
this case the environment did not cause variation in the exposed
parental generation. Instead, it was acting on the parental reproduc-
tive systems, yielding variability, first manifested in the subsequent
offspring. Moreover, such variability bore no necessary relation to
the nature of the environmental influences, and the variants were
not all the same — the variation was "indefinite." Clearly this is
not a Lamarckian conception. Here is where Darwin believed were
to be found the numerous small individual differences upon which
natural selection could act in a gradual but cumulative fashion.
Just how un-Lamarckian, then, is the first edition of the Origin 7 .
Lamarckian variation is there, under the terms "direct action of the
conditions of life" and the inheritance of "habit," and hence "use
and disuse." "Direct" because in this case the variation is produced
directly in the parent and then reproduced in the offspring. It is
also adaptive, as in the case of thick fur under cold climates. Since
all exposed individuals are affected in the same manner, Darwin
called this variation "definite." He followed his mentor in physiol-
ogy, Johannes Muller, in doubting many cases of this kind. "Some
slight amount of change" was as far as he would go [Origin, 11). On
habit, his own experiments comparing the skeletons of domestic and
wild ducks were designed to test this effect. The results revealed a
contrast that he attributed to "the domestic duck flying much less,
and walking more, than its wild parent." He also mentioned the
drooping ears of many domestic animals, due probably to the disuse
of the ear muscles "from the animals not being much alarmed by
danger" (ibid.).
Summing up Chapter 1, Darwin declared;
I believe that the conditions of life, from their action on the reproductive
system, are so far of the highest importance as causing variability. I do
not believe that variability is an inherent and necessary contingency, under
all circumstances, with all organic beings, as some authors have thought.
[Origin, 43)
His close friend and scientific correspondent Joseph Hooker dis-
agreed and advised him to start by adopting instead variation as a
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36 ROBERT OLBY
"fundamental" and "innate principle; & afterwards [make] a few
remarks, showing that hereafter perhaps this principle would be
explicable" (Darwin paraphrasing Hooker's suggestion, Correspon-
dence, 10: 135).
BREEDS OF THE DOMESTIC PIGEON
Center stage in Darwin's treatment of variation in the Origin is
occupied by the breeds of pigeons. One quarter of Chapter 1 is given
to them. This was for two reasons:
1 . Because they displayed such a remarkable diversity of char-
acteristics. Consider the tumblers, Jacobins, pouters, runts,
barbs, carriers, trumpeters, f antails, laughers, and more, each
looking as distinctive as the several species of a genus. Yet
all produced viable offspring when crossed with one another,
suggesting their descent from the same aboriginal form.
2. In 1855 he discovered that two Frenchmen, Boitard and
Corbie, had reported characteristics of the wild rock dove
in the progeny of hybrids between different domestic breeds
(Boitard and Corbie 1824) — slate-blue plumage, two black
wing bars, white rump, and a terminal dark bar to the tail,
its feathers being white at the edges [Origin, 25). This could
provide stunning evidence for the origin of all these breeds
from a single species. Darwin set to work, and by Novem-
ber 1855 he was inviting Charles Lyell to visit and see his
pigeons [Correspondence, 5: 492).
Most breeders thought otherwise. They were convinced that in
former times a distinct progenitor of each of their breeds had existed.
And indeed Boitard and Corbie thought their work indicated that
the breeds in question were distinct species. To Darwin neither of
these conclusions was plausible. As for the numerous alleged orig-
inating species, there was no sign of their former presence. Even
if hybridization between aboriginal forms were also involved, he
reckoned, "at least seven or eight aboriginal stocks" would still be
required to yield all the varieties in existence. He tried crossing
different breeds himself, and noted the uniformity of the [F 1 ] gener-
ation. But in succeeding generations bred from them [F 2 . . . ], "hardly
two of them will be alike, and then the extreme difficulty, or rather
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Variation and Inheritance 3 7
utter hopelessness, of the task becomes apparent" [Origin, 20). From
this point on in the Origin, Darwin's message to the reader on vari-
ation is firmly against cross-breeding as a significant source of new
forms.
Darwin's discussion of variation under nature in Chapter 2 is
dominated by the results of his enquiry into the comparison of the
number of varieties presented by species belonging to large genera
compared to those presented by those belonging to smaller genera.
The tables he used to assemble the quantitative data did not appear
in the Origin [Species Book, 149-54), but their message was clear to
him when he placed the larger genera on one side of a table and the
smaller on the other. He found that
it has invariably proved to be the case that a large proportion of the species
on the side of the larger genera present varieties, than on the side of the
smaller genera. Moreover, the species of the larger genera which present any
varieties, invariably present a larger average number of varieties than do the
species of the smaller genera .... These facts are of plain signification on
the view that species are only strongly marked and permanent varieties,- for
wherever many species of the same genus have been formed, or where, if
we may use the expression, the manufactory of species has been active, we
ought generally to find the manufactory still in action, more especially as
we have every reason to believe the process of manufacturing a new species
to be a slow one. [Origin, 55-6)
Darwin's most trenchant critic, Fleeming Jenkin, was to complain
about the approach adopted here, for it is an argument by default.
Darwin wanted his explanation to be accepted because it was better
than the creationists' explanation. But, objected Jenkin, "our inabil-
ity to account for certain phenomena, in any way but one, is no proof
of the truth of the explanation given, but simply is a confession of
our ignorance" (Hull 1973, 340).
HYBRIDIZATION AND CROSS-BREEDING
In Chapter 1, Darwin declared that the creation of distinct races by
crossing "has been greatly exaggerated." Indeed, he could "hardly
believe" that in this manner "a race could be obtained nearly inter-
mediate between two extremely different races or species" [Origin,
20). He repeated this claim at the end of the chapter, using the
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38 ROBERT OLBY
same phrase, "greatly exaggerated" [Origin, 43). The full treatment
of hybridism comes in Chapter 8, but here neither the laws of hered-
ity nor those of variation are on the agenda. Instead, the discussion
of hybridism serves to explore the nature of sterility in order to show
that it is not "a specially acquired or endowed quality but is inciden-
tal on other acquired differences" [Origin, 245). In this way Darwin
sought to undermine the claim that sterility is the Creator's way
of preserving the fixity of species. That claim had been supported
by the assumed sterility of hybrids (species crosses) in contrast to
the fertility of mongrels (variety crosses). Accordingly, his theme
for the chapter is the degrees of fertility and sterility of hybrids and
mongrels, relying chiefly on the experimental studies of Kolreuter
and Gartner. Darwin's aim was to construct a continuum between
hybrids and mongrels regarding this phenomenon. Cautiously, he
concluded the chapter by remarking that "the facts briefly given in
this chapter do not seem to me opposed to, but even rather to support
the view, that there is no fundamental distinction between species
and varieties" [Origin, 278).
Darwin did not consider the act of hybridization itself to be the
source of the resulting variation. Instead, he subsumed it under what
for him was the more fundamental process, namely, the action of
changed conditions of life. Hence his "double parallel" between the
effects of changed conditions and hybridism.
The sterility of hybrids, which have their reproductive systems imperfect,
and which have had this system and their whole organization disturbed
by being compounded of two distinct species, seems closely allied to that
sterility which so frequently affects pure species, when their natural con-
ditions of life have been disturbed. This view is supported by a parallelism
of another kind; - namely, that the crossing of forms only slightly different
is favourable to the vigour and fertility of their offspring; and that slight
changes in the conditions of life are apparently favourable to the vigour and
fertility of all organic beings. [Origin, 277)
Nine years later he was to ask: "Can this parallelism be accidental?
Does it not rather indicate some real bond of connection?" (Darwin
1868, 2: 177) Another eight years on he answered:
The most important conclusion at which I have arrived is that the mere
act of crossing by itself does no good. The good depends on the individuals
which are being crossed differing slightly in constitution, owing to their
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Variation and Inheritance 3 9
progenitors having been subjected during several generations to slightly dif-
ferent conditions, or to what we call in our ignorance spontaneous variation.
(Darwin 1878, 27)
What irony that the one who had revealed the way in which
so many hermaphrodite organisms are designed to prevent self-
fertilization was the same author who belittled the role of crossing
in the generation of variability! Was this not due to his concern to
provide his theory of natural selection with the appropriate kind of
variations — small differences — appropriate, that is, for their grad-
ual, stepwise accumulation under natural selection? For how else
could adaptive change be achieved and natural selection's creative
role be assured?
INHERITANCE
Admitting that the "laws governing inheritance are quite unknown"
[Origin, 13), Darwin singled out one rule: "at whatever period of life
a peculiarity appears, it tends to appear in the offspring at a corre-
sponding age, though sometimes earlier" (ibid.). The time of onset
of hereditary diseases, especially those known as diatheses, offered
him striking examples. This rule, he judged, was of the "highest
importance in explaining the laws of embryology" (Origin, 14). It
seems he was suggesting that the cause of the sequential develop-
ment of organs (etc.) was to be understood in terms of the particular
nature of the hereditary process involved. Of course, he was consid-
ering inheritance as part of that broader nineteenth- century concept
of "generation," which included both regeneration and embryologi-
cal development. Nevertheless, like his contemporaries, he referred
to what it is that governs inherited traits by the term "constitu-
tion. "Thus in the quotation given earlier, he refers to individuals
"differing slightly in constitution." Then again, discussing the phe-
nomena of acclimatization, he regards "adaptation to any special
climate as a quality readily grafted on an innate wide flexibility
of constitution" (Origin, 141). The term "constitution" appears at
least two dozen times in the book. It was widely used in the medical
literature on diatheses (Olby 1993, 4i2ff.).
When he considered the faithful hereditary transmission of rare
abnormalities - "albinism, prickly skin (ichtheosis), hairy bodies
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40 ROBERT OLBY
&.c," he reasoned that "less strange and commoner deviations may be
freely admitted to be inheritable. Perhaps the correct way of viewing
the whole subject, would be, to look at the inheritance of every
character whatever as the rule, and non-inheritance as the anomaly."
[Origin, 13)
However, he did draw the line at the inheritance of mutilations
( Origin, 135). Nor did he judge that variations acquired rapidly would
be inherited. Curiously, he also expected that offspring born before
the parent has reached full maturity will lack those characters not
yet developed in the parent - for example, the horns of horned cattle.
Another feature of inheritance that he highlighted was the "cor-
relation of growth." That is: "The whole organization is so tied
together during its growth and development, that when slight vari-
ations in any one part occur, and are accumulated through natural
selection, other parts become modified" [Origin, 143). Some of these
correlations he found "quite obscure" - for instance, blue eyes and
deafness in cats, feathered feet and skin between the outer toes in
pigeons. Were these, he queried, due to growth, or to two quite sep-
arate modifications of the inherited constitution? [Origin, 146)
The feature of inheritance that Darwin discussed at some length is
reversion. He recognized the tendency of hybrid offspring to return
to the character of their originating species as a problem for the
generation of novel descendents, their characteristics intermediate
between those of the two originating species. But he denied that
there was any good evidence that domesticated varieties, when "run
wild, gradually but certainly revert in character to their aboriginal
stocks" [Origin, 14). He suggested experiments that could be carried
out to test the claim [Origin, 19).
Reversion was for him a form of ancestral inheritance. That meant
that he included under the term any returns to a distant ancestor,
usually termed "atavism." While reversion was considered the bar-
rier that kept hybrids from becoming new constant forms, atavism
was the phenomenon Darwin used to assert the common descent of
domesticated breeds from a single source - famously, pigeons from
the rock dove [Origin, 27 it.) and horses from some striped animal
like a zebra or quagga [Origin, 167). His discussion of the means
by which these cases of distant reversion could occur reveals his
assumption of what we may call the fractional theory of inheritance,
that is, assuming that bisexual reproduction involves a blending of
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Variation and Inheritance 41
the constitutions of two individuals, then the hereditary contribu-
tion of each ancestor will be halved in each generation. Darwin then
calculated that:
After twelve generations, the proportion of blood, to use a common expres-
sion, of any one ancestor, is only 1 in 2048; and yet, as we see, it is generally
believed that a tendency to reversion is retained by this very small propor-
tion of foreign blood. . . . When a character which has been lost in a breed,
reappears after a great number of generations, the most probable hypothesis
is, not that the offspring suddenly takes after an ancestor some hundred
generations distant, but that in each successive generation there has been
a tendency to reproduce the character in question, which at last, under
unknown favourable conditions, gains an ascendancy. [Origin, 160-1)
This notion of latent tendencies can perhaps be accommodated
in a model of hereditary determination by powers, but hardly by a
fractionating process. Interestingly, Darwin did not appeal to such
"latencies" when, ten years later, he was confronted by the Scottish
engineer Fleeming Jenkin's calculation of the "swamping" effect of
an outbreeding population on rare variants (Hull 1973, 303ff.). This
calculation appeared in Jenkin's (anonymous) review of the fourth
edition of the Origin. After reading it, Darwin confessed to Hooker:
"Fleeming Jenkins [sic] has given me much trouble, but has been of
more real use to me than any other essay" [More Letters, 1: 379).
Assuming blending inheritance, Jenkin claimed that in an outbreed-
ing population, 'single' variations, in spite of being advantageous,
will soon be swamped by the hereditary contributions of the indi-
viduals with whom they will breed.
Jenkin's critique was directed at the imaginary illustration Darwin
had given, in the first four editions of the Origin, of wolves preying
on deer. Darwin had asserted that the slimmest and fleetest wolves
would have an advantage over the slower and heavier and that their
descendants would increase, spreading through the population. Then
he illustrated the case of a single wolf as follows:
Now if any slight innate change of habit or of structure benefited an individ-
ual wolf, it would have the best chance of surviving and of leaving progeny.
Some of its young would probably inherit the same habits or structure, and
by the repetition of this process, a new variety might be formed. . . . {Origin,
9i)
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42 ROBERT OLBY
In the fifth edition (1869) of the Origin, Darwin altered this pas-
sage by substituting "the slimmest individual wolves" for a "sin-
gle wolf," explaining that he had not appreciated "how rarely single
variations, whether slight or strongly marked, could be perpetuated"
until he had read Jenkin's review [Variorum, 178). This revision was
minor. He did not go further into Jenkin's critique on this subject.
But Jenkin had gone on to point out that if the variant were a non-
blending "sport," 2 then
a great number of offspring will retain in full vigour the peculiarity con-
stituting the favourable sport. . . . [L]et all his descendants retain his pecu-
liarity in an eminent degree, however little of the first ancestor's blood be
in them, then it follows, from mere mathematics, that the descendants of
our gifted beast will probably exterminate the descendants of his inferior
brethren. . . . What is this but stating that, from time to time, a new species
is created? (Hull 1973, 317-18)
Jenkin was clearly seeking to force Darwin to take a position that
his critics could interpret as a form of continuous creation. Varia-
tion would thus take away from natural selection its most important
and creative role — accounting for adaptation. Darwin preferred to
hope that by relying on individual differences and assuming their
great prevalence, he could leave the nonblending "sports" on one
side. Accordingly, he altered two passages in the Origin where he
had emphasized the rarity of useful adaptations. The first edition
passage "variations useful to each being . . . should sometimes occur
in the course of thousands of generations" was changed in the sixth
edition to "in the course of many successive generations" [Origin,
80; Variorum, 38). And the passage in the first edition, "Nothing can
be effected, unless favourable variations occur, and variation itself
is apparently always a very slow process," was changed in the fifth
edition to: "Although all the individuals of the same species differ
more or less from each other, differences of the right nature, bet-
ter adapted to the then existing conditions, may not soon occur"
[Origin, 108; Variorum, 202). Darwin clearly aimed to make natural
selection, rather than the availability of variations, the chief limit-
ing factor on the rate of evolutionary change. This debate over the
"Sport" here means an individual that deviates singularly and spontaneously from
the rest of the population.
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Variation and Inheritance 43
"swamping effect" continued to the end of the nineteenth century
and has been discussed elsewhere (Bulmer 2004).
AN IMAGINARY SIXTH EDITION
Anyone in 1859 reading the chapters of the Origin discussed here
was made well aware that Darwin was forcing his way through fresh
territory. "Our ignorance of the laws of variation is profound/' he
acknowledged [Origin, 167). "Nevertheless, we can here and there
dimly catch a faint ray of light, and we may feel sure that there
must be some cause for each deviation of structure, however slight"
[Origin, 132). That being the case, why did he so consistently push
to one side the resource of variation provided by cross-breeding in
the form of what we refer to as genetic recombination? Of course,
recombination on its own would not have been enough. He needed
some source of spontaneous change as well. But he could have uti-
lized both genetic recombination and innate variability, however
caused. The suggestion here is that changed conditions of life offered
him the foundation stone for his theory of variation. Domestication
of animals and cultivation of plants were less important for the
opportunities they gave for cross-breeding than they were for the
opportunities they afforded for changed conditions to act and for
humankind to select the resulting variations. Cross-breeding, inso-
far as it brought together the effects of different conditions of life in
the hybrid constitution, was icing on the cake.
Appealing to innate variability of unknown cause had no attrac-
tion for Darwin. That would open the door to creationist influ-
ences — St. George Mivart provides a case in point. Those, like Pallas,
who gave a central role to hybridization obviously needed a substan-
tial stock of species to begin the process. Darwin repeatedly pointed
to the limits of such a mechanism.
It is therefore instructive to see how Gregor Mendel, in the closing
passages of his 1865 paper, challenged the very essence of Darwin's
conception of variation, declaring:
The opinion has often been expressed that the stability of the species is
greatly disturbed or entirely upset by cultivation. . . . No one will seriously
maintain that in the open country the development of plants is ruled by
other laws than in the garden bed. . . . Were the change in the conditions
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44 ROBERT OLBY
the sole cause of variability we might expect that those cultivated plants
which are grown for centuries under almost identical conditions would again
attain constancy. That, as is well known, is not the case .... Our cultivated
plants are members of various hybrid series whose further development in
conformity with law is varied and interrupted by frequent crossing inter se.
(Mendel 1865, section 10)
Let us imagine what might have happened had Darwin seen
Mendel's paper. We know that when he read Charles Naudin's paper
of 1 865 he judged that the French hybridist's notion of germinal seg-
regation in hybrids would not account for "distant reversion," as
Darwin had found it in pigeons. But Mendel's paper was far more
impressive than Naudin's. Moreover, as cited earlier, Mendel con-
fronted Darwin head-on over his claims for the difference between
the conditions of life under cultivation and in the wild. If Darwin
took due note of Fleeming Jenkin's critique, would he not have been
impressed by Mendel?
To accept Mendel's critique would surely have overturned the
argument for the role of the conditions of life. But it would not have
undermined the case for some unknown cause of innate variation -
call it mutation, as did the Dutch botanist Hugo de Vries in 1 901 . The
external environment could still have been implicated, although - as
Mendel, his teacher Franz Unger, and Mendel's contemporary Kerner
von Marilaun had all demonstrated, simply transporting a species
from one location to another or from the wild into the garden did
not yield lasting variations. Furthermore, cross-breeding does pro-
duce individual differences, does create novelties, as had been proven
again and again by the very breeders Darwin had consulted.
But Mendel's pea characteristics were all strongly marked ones.
They were not the stuff of what Darwin considered to be individual
differences. Would Darwin have launched a major breeding program
along the lines of Mendel's experiments, had he known of them? Can
we picture the multitude of pigeon houses that would be needed,
crowded around Down House in order to reproduce Mendel's results
in an animal? Darwin's pigeon research was unpleasant enough with
just a few birds, but with thousands of birds, what would it have been
like?
Mendel's results were established with strongly marked (non-
blending) characters. Such were not, in Darwin's opinion, relevant
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Variation and Inheritance 45
to evolution. Just such an objection was voiced by British evolution-
ists in the early years of the twentieth century after Mendel's work
had been rediscovered. Thus, in his critical survey of 1908, Alfred
Russel Wallace belittled Mendel's achievement and quoted Darwin
to the effect that "hybridization . . . had no place whatever in the
natural process of species-formation"; and that, he added, "was the
reason why Darwin did not prosecute the research further." Wallace
preferred Darwin's text to "any amount of study of the complex
diagrams and tabular statements which the Mendelians are for ever
putting before us with great flourish of trumpets and reiterated asser-
tions of their importance." Wallace's anger grew as he wrote. For the
Mendelians to "set upon a pinnacle this mere side-issue of biologi-
cal research" was to invite ridicule. Their claims were, he declared,
"monstrous" (Wallace 1908). The distinguished Oxford Darwinian
Sir Edward Poulton reported that all the eminent zoologists to whom
he explained his grounds for indicting the Mendelian writings as
"injurious to Biological Science, and a hindrance in the attempt to
solve the problem of evolution" had agreed with him (Poulton 1 908).
Reginald Punnett, a colleague of the Mendelian William Bateson,
replied: "The Sacred College has convened and orthodoxy has spo-
ken through its chosen mouthpiece" (Punnett 1909, 107).
The great German evolutionist August Weismann was cautious
on Mendel in public, but writing to his translator, William Parker,
he expressed his dislike of mathematics and his expectation that
reduction division in animals introduces complications that are not
present in plants (Churchill 1999, 1: 375). Famous for his denial of the
inheritance of acquired characters and his reliance on cross-breeding
for the emergence of variation, Weismann had long claimed that for
the original source of variation one had to turn to lower forms of
life, where there is no separation between germ cells and body cells.
In the course of evolution, he explained, higher forms, by cross-
breeding, expose these variations, combining them in myriad ways.
But in Weismann's great book, The Germ-Plasm, the arch-critic of
variation due to changes in the conditions of life made a 180 turn.
Now he accepted the "slight inequalities of nutrition in the germ-
plasm" (Weismann 1893, 431) as the cause of individual variations,
as had Darwin in 1859. If Weismann at the close of the century felt
he needed external conditions in order to produce variation, surely
the Darwinians would too? And if Darwin had known and accepted
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4-6 ROBERT OLBY
Mendel's critique, his supporters would surely have drowned out his
admission!
Has the analysis in this chapter any relevance to current concerns
over the adequacy of evidence for evolution by natural selection?
Clearly not. Instead, it serves to remind us forcibly how much the
evidence has strengthened since 1859. Furthermore, it should serve
to underline Darwin's courage in publishing his theory at a time
when much of the data on variation and inheritance was confused.
Hopefully, it will also prove an antidote to any tendency to assume
that when Darwin pondered and wrote about variation and heredity,
he was always thinking along the same lines as that do today.
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ROBERT J. RICHARDS
4 Darwin's Theory of Natural
Selection and Its Moral Purpose
Thomas Henry Huxley recalled that after he had read Darwin's Ori-
gin of Species, he had exclaimed to himself: "How extremely stupid
not to have thought of that!" (Huxley 1900, 1: 183). It is a famous
but puzzling remark. In his contribution to Francis Darwin's Life
and Letters of Charles Darwin, Huxley rehearsed the history of his
engagement with the idea of transmutation of species. He men-
tioned the views of Robert Grant, an advocate of Lamarck, and
Robert Chambers, the anonymous author of Vestiges of the Nat-
ural History of Creation (1844), which advanced a crude idea of
transmutation. He also recounted his rejection of Agassiz's belief
that species were progressively replaced by the divine hand. He
neglected altogether his friend Herbert Spencer's early Lamarck-
ian ideas about species development, which were also part of the
long history of his encounters with the theory of descent. None of
these sources moved him to adopt any version of the transmutation
hypothesis.
Huxley was clear about what finally led him to abandon his long-
standing belief in species stability:
The facts of variability, of the struggle for existence, of adaptation to con-
ditions, were notorious enough; but none of us had suspected that the road
to the heart of the species problem lay through them, until Darwin and
Wallace dispelled the darkness, and the beacon-fire of the "Origin" guided
the benighted. (Huxley 1900, 1: 179-83)
The elements that Huxley indicated - variability, struggle for exis-
tence, adaptation - form core features of Darwin's conception of
natural selection. Thus what Huxley admonished himself for not
47
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48 ROBERT J. RICHARDS
immediately comprehending was not the fact, as it might be called,
of species change but the cause of that change. Huxley's exclamation
suggests - and it has usually been interpreted to affirm - that the idea
of natural selection was really quite simple and that when the few
elements composing it were held before the mind's eye, the principle
and its significance would flash out. The elements, it is supposed,
fall together in the following way: species members vary in their
heritable traits; more individuals are produced than the resources of
the environment can sustain; those that by chance have traits that
better fit them to circumstances compared to others of their kind
will more likely survive to pass on those traits to offspring; conse-
quently, the structural character of the species will continue to alter
over generations until individuals come to be specifically different
from their ancestors.
Yet, if the idea of natural selection were as simple and fundamen-
tal as Huxley suggested and as countless scholars have maintained,
why did it take so long for the theory to be published after Darwin
supposedly discovered it? And why did it then require a very long
book to make its truth obvious? In this chapter, I will try to answer
these questions. I will do so by showing that the principle of natural
selection is not simple but complex and that it took shape only gradu-
ally in Darwin's mind. In what follows, I will refer to the "principle"
or "device" of natural selection, never to the "mechanism" of selec-
tion. Though the phrase "mechanism of natural selection" comes
trippingly to our lips, it never came to Darwin's in the Origin-, and I
will explain why. I will also use the term "evolution" to describe the
idea of species descent with modification. Somehow the notion has
gained currency that Darwin avoided the term because it suggested
progressive development. This assumption has no warrant for two
reasons. First, the term is obviously present, in its participial form,
as the very last word of the Origin, as well as being freely used as
a noun in the last edition of the Origin (1872), in the Variation of
Animals and Plants under Domestication (1868), and throughout
The Descent of Man (1871) and The Expression of the Emotions in
Man and Animals (1872). But the second reason for rejecting the
assumption is that Darwin's theory is indeed progressivist, and his
device of natural selection was designed to produce evolutionary
progress.
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Natural Selection and Its Moral Purpose 49
darwin's early efforts to explain
transformation
Shortly after he returned from his voyage on HMS Beagle (1831-36),
Darwin began seriously to entertain the hypothesis of species change
over time. He had been introduced to the idea, when a teenager,
through reading his grandfather Erasmus Darwin's Zoonomia (1794-
96), which included speculations about species development; and,
while at medical school in Edinburgh (1825-27), he had studied
Lamarck's Systeme des animaux sans vertebres (1801) under the
tutelage of Robert Grant, a convinced evolutionist. On the voyage,
he took with him Lamarck's Histoire naturelle des animaux sans
vertebres (1815-22), in which the idea of evolutionary change was
prominent. He got another large dose of the Frenchman's ideas dur-
ing his time off the coast of South America, where he received by
merchant ship the second volume of Charles Lyell's Principles of
Geology (1831-33), which contained a searching discussion and neg-
ative critique of the fanciful supposition of an "evolution of one
species out of another" (Lyell 1987, 2: 60). Undoubtedly the rejec-
tion of Lamarck by Lyell and most British naturalists gave Darwin
pause; but after his return to England, while sorting and cataloguing
his specimens from the Galapagos, he came to understand that his
materials supplied compelling evidence for the suspect theory.
In his various early notebooks (January 1 8 3 7 to June 1838), Darwin
began to work out different possible ways to explain species change
(Richards 1987, 85-98). Initially, he supposed that a species might
be "created for a definite time," so that when its span of years was
exhausted, it went extinct and another, affiliated species took its
place [Notebooks, 12, 62). He rather quickly abandoned the idea
of species senescence, and began to think in terms of Lamarck's
notion of the direct effects of the environment, especially the possi-
ble impact of the imponderable fluids of heat and electricity [Note-
books, 175). If the device of environmental impact were to meet
what seemed to be the empirical requirement - as evidenced by
the pattern of fossil deposits, going from simple shells at the deep-
est levels to complex vertebrate remains at higher levels - then it
had to produce progressive development. If species resembled ideas,
then progressive change would seem to be a natural result, or so
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50 ROBERT J. RICHARDS
Darwin speculated: "Each species changes. Does it progress. Man
gains ideas. The simplest cannot help. - becoming more complicated;
& if we look to first origin there must be progress" [Notebooks, 175).
Being the conservative thinker that he was, Darwin retained in the
Origin the idea that some species, under special conditions, might
alter through direct environmental impact as well as the conviction
that modifications would be progressive.
Darwin seems to have soon recognized that the direct influence
of surroundings on an organism could not account for its more
complex adaptations, and so he began constructing another causal
device. He had been stimulated by an essay of Frederic Cuvier, which
suggested that animals might acquire heritable traits through exer-
cise in response to particular circumstances. He rather quickly con-
cluded that "all structures either direct effect of habit, or hereditary
<& combined> effect of habit" [Notebooks, 25 9 j. 1 Darwin thus
assumed that new habits, if practiced by the population over long
periods of time, would turn into instincts; and these latter would
eventually modify anatomical structures, thus altering the species.
Use inheritance was, of course, a principal mode of species transfor-
mation for Lamarck.
In developing his own theory of use inheritance, Darwin care-
fully distinguished his ideas from those of his discredited predeces-
sor - or at least he convinced himself that their ideas were quite
different. He attempted to distance himself from the French natu-
ralist by proposing that habits introduced into a population would
first gradually become instinctual before they altered anatomy. And
instinct - innate patterns of behavior - would be expressed auto-
matically, without the intervention of conscious will power, the
presumptive Lamarckian mode [Notebooks, 292). By early summer
of 1838, Darwin thus had two means by which to explain descent of
species with modification: the direct effects of the environment and
his habit-instinct device.
ELEMENTS OF THE THEORY OF NATURAL SELECTION
At the end of September 1838, Darwin paged through Thomas
Malthus's Essay on the Principle of Population. As he later recalled
1 Single wedges indicate erasure; double wedges indicate addition.
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Natural Selection and Its Moral Purpose 5 1
in his Autobiography, this happy event changed everything for his
developing conceptions:
I soon perceived that selection was the keystone of man's success in making
useful races of animals and plants. But how selection could be applied to
organisms living in a state of nature remained for some time a mystery to
me.
In October 1838, that is, fifteen months after I had begun my system-
atic enquiry, I happened to read for amusement Malthus on Population, and
being well prepared to appreciate the struggle for existence which every-
where goes on from long-continued observation of the habits of animals and
plants, it at once struck me that under these circumstances favourable vari-
ations would tend to be preserved, and unfavourable ones to be destroyed.
The result of this would be the formation of new species. Here, then, I had
at last got a theory by which to work. [Autobiography, 119-20)
Darwin's description provides the classic account of his discovery
and it does capture a moment of that discovery though not the com-
plete character or full scope of his mature conception. The account in
the Autobiography needs to be placed against the notebooks, essays,
and various editions of the Origin and The Descent of Man. These
comparisons will reveal many moments of discovery, and a gradual
development of his theory of natural selection from 1838 through
the next four decades.
In the Autobiography, Darwin mentioned two considerations that
had readied him to detect in Malthus a new possibility for the expla-
nation of species development: the power of artificial selection and
the role of struggle. Lamarck had suggested domestic breeding as
the model for what occurred in nature. Undeterred by Lyell's objec-
tion that domestic animals and plants were specially created for
man (Lyell 1987, 2: 41), Darwin began reading in breeders' man-
uals, such as those by John Sebright (1809) and John Wilkinson
(1820). This literature brought him to understand the power of
domestic "selection" (Sebright's term), but he was initially puz-
zled, as his Autobiography suggests, about what might play the
role of the natural selector or "picker." In midsummer of 1838, he
observed:
The Varieties of the domesticated animals must be most complicated,
because they are partly local & then the local ones are taken to fresh country
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52 ROBERT J. RICHARDS
&. breed confined, to certain best individuals. - scarcely any breed but what
some individuals are picked out. - in a really natural breed, not one is picked
out. . . . [Notebooks, 337)
In this passage, he appears to have been wondering how selecting
could occur in nature when no agent was picking the few "best
individuals" to breed.
In the Autobiography, Darwin indicated that the second idea that
prepared the way for him to divine the significance of Malthus's
Essay was that of the struggle for existence. Lyell, in the Princi-
ples of Geology, had mentioned de Candolle's observation that all
the plants of a country "are at war with one another" (Lyell 1987,
2: 131). This kind of struggle, Lyell believed, would be the cause
of "mortality" of species, of which fossils gave abundant evidence
(Lyell 1987, 2: 130). In his own reading of Lyell, Darwin took to heart
the implied admonition to "study the wars of organic being" [Note-
books, 262).
These antecedent notions gleaned from Lamarck, Lyell, and the
breeders led Darwin to the brink of a stable conception that would
begin to take more explicit form after his reading of Malthus's Essay
in late September 1838. In spring of 1837, for instance, he considered
how a multitude of varieties might yield creatures better adapted to
circumstances: "whether every animal produces in course of ages
ten thousand varieties, (influenced itself perhaps by circumstances)
&. those alone preserved which are well adapted" [Notebooks, 193).
Here Darwin mentioned in passing a central element of his principle
of natural selection without, apparently, detecting its significance.
And a year later something like both natural and sexual selection
spilled onto the pages of his Notebook C: "Whether species may not
be made by a little more vigour being given to the chance offspring
who have any slight peculiarity of structure. <<hence seals take
victorious seals, hence deer victorious deer, hence males armed &.
pugnacious all orders; cocks all war-like)>>" [Notebooks, 258; likely
a gloss on Sebright 1809, 15-16). It is fair to say, nonetheless, that
the foundations for Darwin's device of natural selection were laid
on the ground of Malthus's Essay. His reading of that book caused
those earlier presentiments to settle into a firm platform for further
development.
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Natural Selection and Its Moral Purpose 5 3
THE MALTHUS EPISODE
Malthus had composed his book in order to investigate two ques-
tions: What has kept humankind from steadily advancing in hap-
piness? Can the impediments to happiness be removed? Famously,
he argued that the chief barrier to the progress of civil society was
that population increase would always outstrip the growth in the
food supply, thus causing periodic misery and famine. What caught
Darwin's eye in the opening sections of Malthus's Essay, as sug-
gested by scorings in his copy of the book, was the notion of popula-
tion pressure through geometric increase:
In the northern states of America, where the means of subsistence have been
more ample . . . the population has been found to double itself, for above
a century and half successively, in less than twenty-five years. ... It may
safely be pronounced, therefore, that population, when unchecked, goes
on doubling itself every twenty-five years, or increases in a geometrical
ratio. . . . But the food to support the increase from the greater number will
by no means be obtained with the same facility. Man is necessarily confined
in room. (Malthus 1914, 5-7)
Darwin found in these passages from Malthus a propulsive force
that had two effects: it would cause the death of the vast number
in the population by reason of the better adapted pushing out the
weaker, and thus it would sort out, or transform, the population. On
September 28, 1838, Darwin phrased it this way in his Notebook D:
Even the energetic language of <Malthus> <<Decandoelle>> does not
convey the warring of the species as inference from Malthus. . . . population
in increase at geometrical ratio in FAR SHORTER time than 25 years - yet
until the one sentence of Malthus no one clearly perceived the great check
amongst men. . . . One may say there is a force like a hundred thousand
wedges trying force <into> every kind of adapted structure into the gaps
<of> in the oeconomy of Nature, or rather forming gaps by thrusting out
weaker ones. <<The final cause of all this wedging, must be to sort out
proper structure &. adapt it to change. [Notebooks, 375-6)
All the "wedging" caused by population pressure would have the
effect, according to Darwin, of filtering out all but the most fit organ-
isms and thus adapting the latter (actually, leaving them pre-adapted)
to their circumstances.
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54 ROBERT J. RICHARDS
Though natural selection is the linchpin of Darwin's theory of
evolution, his notebooks indicate only the slow emergence of its
ramifying features. He reflected on his burgeoning notions through
the first week of October 1838, but then turned to other matters.
Through the next few months, here and there, the implications
became more prominent in his thought. In early December, for
instance, he explicitly drew for the first time the analogy between
natural selection and domestic selection: "It is a beautiful part of my
theory, that <<domesticated>> races . . . are made by percisely [sic]
same means as species" [Notebooks, 416). But the most interesting
reflections, which belie the standard assumptions about Darwin's
theory, were directed to the final cause or purpose of evolution.
This teleological framework would help to organize several other
elements constituting his developing notion.
THE PURPOSE OF PROGRESSIVE EVOLUTION! HUMAN
BEINGS AND MORALITY
The great peroration at the very end of the Origin of Species asserts
a long-standing and permanent conviction of Darwin, namely, that
the "object," or purpose, of the "war of nature" is "the production
of the higher animals" [Origin, 490). And the unspoken, but clearly
intended, higher animals are human beings with their moral senti-
ments. Darwin imbedded his developing theory of natural selection
in a decidedly progessivist and teleological framework, a framework
quite obvious when one examines the initial construction of his
theory.
At the end of October 1838, he focused on the newly formulated
device:
My theory gives great final cause <<I do not wish to say only cause, but one
great final cause . . . >> of sexes . . . for otherwise there would be as many
species, as individuals, &. . . . few only social . . . hence not social instincts,
which as I hope to show is <<probably>> the foundation of all that is
most beautiful in the moral sentiments of the animated beings. [Notebooks,
409)
In this intricate cascade of ideas, Darwin traced a path from sexual
generation to its consequences: the establishment of stable species,
then the appearance of social species, and finally the ultimate
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Natural Selection and Its Moral Purpose 5 5
purpose of the process, the production of human beings with their
moral sentiments. This trajectory needs further explication.
When Darwin opened his first transmutation notebook in the
spring of 1837, he began with his grandfather's reflections on the
special value of sexual generation over asexual kinds of reproduc-
tion. The grandson supposed that sexually produced offspring would,
during gestation, recapitulate the forms of ancestor species. As he
initially put the principle of recapitulation: "The ordinary kind [i.e.,
sexual reproduction], which is a longer process, the new individual
passing through several stages (typical, <of the> or shortened rep-
etition of what the original molecule has done)" [Notebooks, 170).
Darwin retained the principle of embryological recapitulation right
through the several editions of the Origin (Nyhart, this volume).
Recapitulation produced an individual that gathered in itself all the
progressive adaptations of its ancestors. But the key to progressive
adaptation was the variability that came with sexual reproduction
[Notebooks, 171). In the spring of 1837, he still did not understand
exactly how variability might function in adaptation; he yet per-
ceived that variable offspring could adjust to a changing environ-
ment in ways that clonally reproducing plants and animals could not.
Moreover, in variable offspring accidental injuries would not accu-
mulate as they would in continuously reproducing asexual organ-
isms. Hence stable species would result from sexual generation.
For "without sexual crossing, there would be endless changes . . . &.
hence there could not be improvement. <<&. hence not <<be>>
higher animals" [Notebooks, 410). But once stable species obtained,
social behavior and ultimately moral behavior might ensue.
Just at the time Darwin considered the "great final cause" of
sexual generation - namely, the production of higher animals with
their moral traits - he opened his Notebook N, in which he began
to compose an account of the moral sentiments. He worked out the
kernel of his conception, which would later flower in The Descent
of Man, in a fanciful example. He imagined the case of a dog with
incipient moral instincts:
Dog obeying instincts of running hare is stopped by fleas, also by greater
temptation as bitch. . . . Now if dogs mind were so framed that he constantly
compared his impressions, &. wished he had done so &. so for his interest, &
found he disobeyed a wish which was part of his system, &. constant, for a
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56 ROBERT J. RICHARDS
wish which was only short & might otherwise have been relieved, he would
be sorry or have troubled conscience - therefore I say grant reason to any
animal with social & sexual instincts <<& yet with passions he must have
conscience - this is capital view. - Dogs conscience would not have been
same with mans because original instinct different. {Notebooks, 563-4)
Darwin believed that the moral instincts were essentially per-
sistent social instincts that might continue to urge cooperative
action even after being interrupted by a more powerful, self-directed
impulse. As he suggested to himself at this time: "May not moral
sense arise from our enlarged capacity <acting> <<yet being
obscurely guided> > or strong instinctive sexual, parental &. social
instincts give rise 'do unto others as yourself, 'love thy neighbour
as thyself. Analyse this out" [Notebooks, 558). He would, indeed,
continue to analyze out his theory; for at this point in its devel-
opment, he did not see how other- directed, social instincts, which
gave no benefit to their carrier, could be produced by selection. This
difficulty seems to have led him to retain the device of inherited
habit to explain the origin of the social instincts. Thus in late spring
of 1839, ne formulated what he called the "law of utility" - derived
from Paley - which supposed that social utility would lead the whole
species to adopt certain habits that, through dint of exercise, would
become instinctive: "On Law of Utility Nothing but that which
has beneficial tendency through many ages [i.e., necessary social
habits] would be acquired. ... It is probable that becomes instinctive
which is repeated under many generations" [Notebooks, 623 ). While
Darwin never gave up the idea that habits could be inherited, he
would solve the problem of the natural selection of social instincts
only in the final throes of composing the Origin.
At the very end of October 1838, Darwin gave an analytic sum-
mary of his developing idea, a neat set of virtually axiomatic princi-
ples constituting his device:
Three principles, will account for all
fi) Grandchildren, like grandfathers
(2) Tendency to small change . . .
(3) Great fertility in proportion to support of parents. [Notebooks, 412-13)
These factors may be interpreted as: traits of organisms are her-
itable (with occasional reversions); these traits vary slightly from
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Natural Selection and Its Moral Purpose 57
generation to generation; and reproduction outstrips food resources
(the Malthusian factor). These principles seem very much like those
"necessary and sufficient" axioms advanced by contemporary evo-
lutionary theorists: variation, heritability, and differential survival
(Lewontin 1978). Such analytic reduction does appear to render evo-
lution by natural selection a quite simple concept, as Huxley sup-
posed. However, these bare principles do not identify a causal force
that might scrutinize the traits of organisms to pick out just those
that could provide an advantage and thus be preserved. Darwin
would shortly construct that force as both a moral and an intelli-
gent agent, and the structure of that conception would sink deeply
into the language of the Origin.
NATURAL SELECTION AS AN INTELLIGENT
AND MORAL FORCE
In 1 842, Darwin roughly sketched the outlines of his theory, and two
years later he enlarged the essay to compose a more complete and sys-
tematic version. In the first section of both essays, as in the first chap-
ter of the Origin, Darwin discussed artificial selection. He suggested
that variations in traits of plants and animals occurred as the result
of the effects of the environment in two different ways: directly,
by the environment's affecting features of the malleable body of
the young progeny; but also indirectly, by the environment's affect-
ing the sexual organs of the parents [Foundations, 1-2). Typically, a
breeder would examine variations in plant or animal offspring, and
if any captured his fancy, he would breed only from those suitable
varieties and prevent back-crosses to the general stock. Back-crosses,
of course, would damp out any advantages the selected organisms
might possess.
In the next section of the essays, Darwin inquired whether varia-
tion and selection could be found in nature. Variations in the wild,
he thought, would occur much as they did in domestic stocks. But
the crucial, two-pronged issue was: "is there any means of selecting
those offspring which vary in the same manner, crossing them and
keeping their offspring separate and thus producing selected races"
[Foundations, 5)? The first of these problems might be called the
problem of selection, the second that of swamping out. In begin-
ning to deal with these difficulties (and more to come), Darwin pro-
posed to himself a certain model against which he would construct
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58 ROBERT J. RICHARDS
his device of natural selection. This model would control his lan-
guage and the concepts deployed in the Origin. In the 1844 essay, he
described the model this way:
Let us now suppose a Being with penetration sufficient to perceive the
differences in the outer and innermost organization quite imperceptible to
man, and with forethought extending over future centuries to watch with
unerring care and select for any object the offspring of an organism produced
under the foregoing circumstances; I can see no conceivable reason why he
could not form a new race for several were he to separate the stock of the
original organism and work on several islands) adapted to new ends. As we
assume his discrimination, and his forethought, and his steadiness of object,
to be incomparably greater than those qualities in man, so we may suppose
the beauty and complications of the adaptations of the new races and their
differences from the original stock to be greater than in the domestic races
produced by man's agency. [Foundations, 85)
The model Darwin had chosen to explain to himself the process of
selection in nature was that of a powerfully intelligent being, one
that had foresight and that selected animals to produce beautiful and
intricate structures. This prescient being made choices that were
"infinitely wise compared to those of man" [Foundations, 21). As
a wise breeder, this being would prevent back-crosses of his flocks.
Nature, the analog of this being, was thus conceived not as a machine
but as a supremely intelligent force.
In the succeeding sections of both essays, Darwin began specify-
ing the analogs for the model, that is, those features of nature that
operated in a fashion comparable to the actions of the imaginary
being. He stipulated, for instance, that variations in nature would be
very slight and intermittent due to the actions of a slowly changing
environment. But, looking to his model, he supposed that nature
would compensate for very gradually appearing variations by acting
in a way "far more rigid and scrutinizing" [Foundations, 9). He then
brought to bear the Malthusian idea of geometrical increase of off-
spring, and the consequent struggle for existence that would cull all
but those having the most beneficial traits.
Many difficulties in the theory of natural selection were yet
unsolved in the essays. Darwin had not really dealt with the
problem of swamping. Nor had he succeeded in working out how
nature might select social, or altruistic, instincts, the ultimate goal
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Natural Selection and Its Moral Purpose 59
of evolution. And as he considered the operations of natural selec-
tion, it seemed improbable that it could produce organs of great
perfection, such as the vertebrate eye. His strategy for solving this
last problem, however, did seem ready to hand - namely, to find a
graduation of structures in various different species that might illus-
trate how organs like the eye might have evolved over long periods
of time. Moreover, if natural selection had virtually preternatural
discernment, it could operate on exquisitely small variations to pro-
duce something as intricate as an eye.
darwin's big species book: group selection
and the morality of nature
In September 1854, Darwin noted in his pocket diary, "Began sort-
ing notes for Species theory." His friends had urged him not to delay
in publishing his theory, lest someone else beat him to the goal.
His diary records on May 14, 1856: "Began by Lyell's advice writing
species sketch." 2 By the following fall, the sketch grew far beyond
his initial intention. His expanding composition was to be called
Natural Selection, though in his notes he referred to it affection-
ately as "my Big Species Book." And big it would have been: his
efforts would have yielded a very large work, perhaps extending to
two or three fat volumes. But the writing was interrupted when
Lyell's prophecy about someone else forestalling him came true. In
mid-June 1858, he received the famous letter from Wallace, then in
Malaya, in which that naturalist included an essay that could have
been purloined from Darwin's notebooks. After reassurances from
friends that honor did not require him to toss his manuscript into
the flames, Darwin compressed that part of the composition already
completed and quickly wrote out the remaining chapters of what
became the Origin of Species.
At the beginning of March 1858, a few months before he was
to receive Wallace's letter, Darwin had finished a chapter in his
manuscript entitled "Mental Powers and Instincts of Animals." In
that chapter he solved a problem about which he had been worrying
for almost a decade. In his study of the social insects - especially
Charles Darwin, Personal Journal MS 34, Cambridge University Library, DAR
158. 1-76.
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60 ROBERT J. RICHARDS
ants and bees - he had recognized that the workers formed different
castes with peculiar anatomies and instincts. Yet the workers were
sterile, and so natural selection could not act on the individuals to
preserve in their offspring any useful habits. How, then, had these
features of the social insects evolved? In a loose note, dated June
1848, in which he sketched out the problem, he remarked, "I must
get up this subject - it is the greatest special difficulty I have met
with. "3
Though Darwin had identified the problem many years before, it
was only in the actual writing of his Big Species Book that he arrived
at a solution. He took his cue from William Youatt's Cattle: Their
Breeds, Management, and Disease (1834). When breeders wished
to produce a herd with desirable characteristics, they would choose
animals from several groups and slaughter them. If one or another
had, say, desired marbling, they would breed from the family of
the animal with that characteristic. 4 In the Species Book, Darwin
rendered the discovery this way:
This principle of selection, namely not of the individual which cannot breed,
but of the family which produced such individual, has I believe been fol-
lowed by nature in regard to the neuters amongst social insects; the selected
characters being attached exclusively not only to one sex, which is a cir-
cumstance of the commonest occurrences, but to a peculiar & sterile state
of one sex. {Species Book, 370)
Darwin thus came to understand that natural selection could
operate not only on individuals but also on whole families, hives, or
tribes. This insight and the expansion of his theory of natural selec-
tion would have two important dividends: first, he could exclude
a Lamarckian explanation of the wonderful instincts of the social
insects - since no acquired habits could be passed to offspring - and
simultaneously he could overcome a potentially fatal objection to
his theory (see Lustig, this volume). But second, this theory of fam-
ily selection (or community selection, as he came to call it) would
enable him to solve the like problem in human evolution, namely,
the origin of the altruistic instincts. In The Descent of Man, Darwin
3 Charles Darwin, Cambridge University Library, DAR 73.1-4. I have discussed the
problem of the social insects in Richards 1987, 142-52.
4 Charles Darwin, Cambridge University Library, DAR 73.1-4.
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Natural Selection and Its Moral Purpose 61
would mobilize the model of the social insects precisely in order to
construct a theory of human moral behavior that contained a core
of pure, unselfish altruism - that is, acts that benefited others at a
cost to self, something that could not occur under individual selec-
tion (Richards 1987, 206-19). Hence the final goal of evolution, as he
originally conceived its telic purpose, could be realized: the produc-
tion of the higher animals having moral sentiments. Yet not only did
Darwin construe natural selection as producing moral creatures, he
conceived of natural selection itself as a moral and intelligent agent.
The model of an intelligent and moral selector, which Darwin cul-
tivated in the earlier essays, makes an appearance in the Big Species
Book. In the chapter "On Natural Selection," he contrasted man's
selection with nature's. The human breeder did not allow "each
being to struggle for life"; rather, he protected animals "from all
enemies." Further, man judged animals only on surface characteris-
tics and often picked countervailing traits. The human breeder also
allowed crosses that reduced the power of selection. And finally,
man acted selfishly, choosing only that property that "pleases or is
useful to him." Nature acted quite differently:
She cares not for mere external appearances; she may be said to scrutinize
with a severe eye, every nerve, vessel & muscle; every habit, instinct, shade
of constitution, - the whole machinery of the organization. There will be
here no caprice, no favouring: the good will be preserve & the bad rigidly
destroyed. [Species Book, 224)
Nature thus acted steadily, justly, and with divine discernment, sep-
arating the good from the bad. Nature, in this conception, was God's
surrogate, which Darwin signaled by penciling in his manuscript
above the passage just quoted: "By nature, I mean the laws ordained
by God to govern the Universe" [Species Book, ii\; see also Brooke,
this volume). As Darwin pared away the overgrowth of the Big
Species Book, the intelligent and moral character of natural selec-
tion stood out even more boldly in the precis, that is, in the Origin
of Species.
NATURAL SELECTION IN THE ORIGIN OF SPECIES
In the first edition of the Origin, Darwin approached natural selec-
tion from two distinct perspectives, conveyed in two chapters whose
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62 ROBERT J. RICHARDS
titles suggest the distinction: "Struggle for Existence" and "Natural
Selection" (Chapters 3 and 4). Though their considerations overlap,
the first focuses on the details of the operations of selection and the
second contains the more highly personified re-conceptualization of
its activities. In Chapter 3, Darwin proposed that small variations in
organisms would give some an advantage in the struggle for life. He
then defined natural selection:
Owing to this struggle for life, any variation, however slight and from what-
ever cause proceeding, if it be in any degree profitable to an individual of any
species, . . . will tend to the preservation of that individual, and will gener-
ally be inherited by its offspring. The offspring, also, will thus have a better
chance of surviving. ... I have called this principle, by which each slight
variation, if useful, is preserved by the term Natural Selection. [Origin, 61)
Darwin would explain what he meant by "struggle" a bit later in
the chapter, and I will discuss that in a moment. Here, I would like
to note several revealing features of his definition. First, selection
is supposed to operate on all variations, even those produced by the
inheritance of acquired characters, and not just on those that arise
accidentally from the environment's acting on the sex organs of par-
ents. Second, Darwin believed that virtually all traits, useful or not,
would be heritable - what he called the "strong principle of inher-
itance" [Origin, 5). Third, though the initial part of the definition
indicates that it is the individual that is preserved, in the second
part it is the slight variation that is preserved - which latter is the
meaning of the phrase "natural selection" [Origin, 61, 81). The pas-
sage draws out the "chicken and egg" problem for Darwin: a trait
gives an individual an advantage in its struggle, so that the individ-
ual is preserved; the individual, in turn, preserves the trait by passing
it on to offspring. Finally, the definition looks to the future, when
useful traits will be sifted out and the nonuseful extinguished, along
with their carriers. In the short run, individuals are preserved; in
the long run, it is their morphologies that are both perpetuated and
slowly changed as the result of continued selection.
"We behold," Darwin observed (using a recurring metaphor), "the
face of nature bright with gladness"; but we do not see the strug-
gle that occurs beneath her beaming countenance [Origin, 62). But
what does "struggle" mean, and who are the antagonists in a strug-
gle for existence? Darwin said he meant "struggle" in a "large and
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Natural Selection and Its Moral Purpose 63
metaphorical sense," which, as he spun out his meandering notion,
would cover three or four distinct meanings [Origin, 62-3). First, an
animal preyed upon will struggle with its aggressor. But as well, two
canine animals will "struggle with one another to get food and live."
The image Darwin seems to have had in mind was that of two dogs
struggling over a piece of meat. Furthermore, struggle can be used
to characterize a plant at the edge of the desert: it struggles "for life
against the drought." In addition, one can say that plants struggle
with other plants of the same and different species for their seeds
to occupy fertile ground. These different kinds of struggle, in Dar-
win's estimation, can be aligned according to a sliding scale of sever-
ity. Accordingly, the struggle will move from most to least intense:
between individuals of the same variety of a species; between indi-
viduals of different varieties of the same species; between individ-
uals of different species of the same genus; between species mem-
bers of quite different types; and finally, between individuals and
climate. These various and divergent meanings of struggle seem to
have come from the two different sources for Darwin's concept: de
Candolle, who proclaimed that all of nature was at war, and Malthus,
who emphasized the consequences of dearth to whole populations.
Today, we would say that struggle - granted its metaphorical sense -
properly occurs only between members of the same species to leave
progeny. Adopting de Candolle's emphasis on the warlike aspects
of struggle may have led Darwin to distinguish natural selection
from sexual selection, which latter concerns not a death struggle for
existence but males' struggling for mating opportunities.
In the chapter "Natural Selection" in the Origin, Darwin charac-
terized his device in this way, pulling phrases from his earlier essays
and Big Species Book but rendering them with a biblical inflexion:
Man can act only on external and visible characters: nature cares nothing
for appearances, except in so far as they may be useful to any being. She can
act on every internal organ, on every shade of constitutional difference, on
the whole machinery of life. Man selects only for his own good; Nature only
for that of the being which she tends. . . . Can we wonder, then, that nature's
productions should be far "truer" in character than man's productions; that
they should be infinitely better adapted to the most complex conditions of
life, and should plainly bear the stamp of far higher workmanship? [Origin,
83-4).
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64 ROBERT J. RICHARDS
The biblical coloring of Darwin's text is condign for a nature that
is the divine surrogate and that acts only altruistically for the wel-
fare of creatures. The attribution of benevolence to nature becomes
explicit in Darwin's attempt to mitigate what might seem the harsh
language of struggle. He concludes his chapter "Struggle for Exis-
tence" with the solace: "When we reflect on this struggle, we may
console ourselves with the full belief, that the war of nature is not
incessant, that no fear is felt, that death is generally prompt, and
that the vigorous, the healthy, and the happy survive and multiply"
[Origin, 79). Darwin's model of moral agency mitigated the force of
Malthusian pitilessness.
CONCLUSION
I have argued that Darwin did not come to his conception of natural
selection in a flash that yielded a fully formed theory. What appears
as the intuitive clarity of his device is, I believe, quite deceptive. I
have tried to show that his notions about the parameters of natural
selection, what it operates on and its mode of operation, gradually
took shape in Darwin's mind, and hardly came to final form even
with the publication of the first edition of the Origin of Species. In
this gradual evolution of a concept - actually a set of concepts - 1 have
emphasized the way Darwin characterized selection as a moral and
intelligent agent. Most contemporary scholars have described Dar-
winian nature as mechanical, even amoral in its ruthlessness. To be
sure, when Wallace and others pointed out what seemed the mis-
leading implications of the device, Darwin protested that, of course,
he did not mean to argue that natural selection was actually an intel-
ligent or moral agent. But even Darwin recognized, if dimly, that his
original formulation of the device and the cognitively laden language
of his writing carried certain consequences with which he did not
wish to dispense - and, indeed, could not dispense with without
altering his deeper conception of the character and goal of evolu-
tion. Darwin's language and metaphorical mode of thought gave his
theory a meaning resistant to any mechanistic interpretation and
unyielding even to his later, more cautious reflections.
Let me spell out some of those consequences to make clear how
markedly Darwin's original notion of evolution by natural selection
differs from what is usually attributed to him. Natural selection,
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Natural Selection and Its Moral Purpose 65
in Darwin's view, moved very slowly and gradually, operating at a
stately Lyellian pace (perhaps seizing on useful variations that might
occur only after thousands of generations; Origin, 80, 82). It compen-
sated for meager variability by daily and hourly scrutinizing every
individual for even the slightest and most obscure variation, select-
ing just those that gave the organism an advantage. A nineteenth-
century machine could not be calibrated to operate on such small
variations or on features that might escape human notice. If natural
selection clanked along like a Manchester spinning loom, one would
not have fine damask - only a skillful and intelligent hand could spin
that - or the fabric of the eye.
Second, Darwin frequently remarked in the Origin that selection
operated more efficiently on species with a large number of individu-
als in an extensive, open area [Origin, 41, 70, 102, 105, 125, 177, 179).
He presumed that, as in the case of the human breeder, a large num-
ber of individual animals or plants would produce more favorable
variations upon which selection might act. The greater quantities
would also create Malthusian pressure. Yet in the wild, this scenario
for selection could occur only if the watchful eye of an intelligent
selector somehow gathered the favored varieties together and iso-
lated them so as to prevent back-crossing into the rest of the stock.
After Fleeming Jenkin, in his review of the Origin, pointed out the
problem of swamping of single variations, Darwin suggested in the
fifth edition that groups of individuals would all vary in the same
way due to the impact of the local environment [Variorum, 179).
Thus when the implications of his model of intelligent nature were
recognized, Darwin had to invoke as analog a Lamarckian scenario.
Today, we assume that small breeding groups isolated by physical
barriers would more likely furnish the requisite conditions for nat-
ural selection.
Third, a wise selector that has the good of creatures at heart
would produce a progressive evolution, one that created ever-more-
improved organization, which Darwin certainly thought to be the
case. He believed that more recent creatures had accumulated pro-
gressive traits and would triumph over more ancient creatures in
comparable environments [Origin, 205-6, 336-7). He summed up
his view in the last section of the Origin: "And as natural selec-
tion works solely by and for the good of each being, all corporeal
and mental endowments will tend to progress towards perfection"
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66 ROBERT J. RICHARDS
[Origin, 489). This passage, which remains unchanged through the
several editions of the Origin, is an index both of Darwin's moral
conception of nature and of its progressive intent. The moral over-
lay of the passage has blotted out the winnowing force of selection,
which hardly works to the benefit of every creature. And, as Dar-
win made clear in the third edition, the "improvements" wrought
by selection will "inevitably lead to the gradual advancement of the
organization of the greater number of living beings throughout the
world" [Variorum, 221).
Fourth, such an intelligent agency would select not merely for
each creature's good, but also for that of the community. Darwin,
in the fifth and sixth editions of the Origin, extended his model of
family selection to one that operated simply on a community: "In
social animals it [natural selection] will adapt the structure of each
individual for the benefit of the community; if this in consequence
profits by the selected change" [Variorum, 172).
Finally, the intelligent and moral character of natural selection
would produce the goal that Darwin had sighted early in his note-
books, namely, the production of the higher animals with their moral
sentiments. Darwin thus concluded his volume with the Miltonic
and salvific vision that he had harbored from his earliest days:
Thus, from the war of nature, from famine and death, the most exalted
object which we are capable of conceiving, namely, the production of the
higher animals, directly follows. There is grandeur in this view of life, with
its several powers, having been originally breathed into a few forms or into
one,- and that, whilst this planet has gone cycling on according to the fixed
laws of gravity, from so simple a beginning endless forms most beautiful
and most wonderful have been, and are being, evolved. [Origin, 490)
Darwin's vision of the process of natural selection was anything
but mechanical and brutal. Nature, while it may have sacrificed a
multitude of its creatures, did so for the higher "object," or purpose,
of creating beings with a moral spine - out of death came life more
abundant. We humans, Darwin believed, were the goal of evolution
by natural selection.
Cambridge Collections Online © Cambridge University Press, 2009
PHILLIP R. SLOAN
Originating Species
Darwin on the Species Problem
Darwin's revolutionary arguments for the transformation of species
emerged against the backdrop of a century-long transnational debate
over the nature of organic species. The aim of this chapter is to clarify
this context and relate it to Darwin's Origin.
Following a brief summary of the "species problem" in the period
before 1850, I analyze some key aspects of Darwin's species con-
cept in the so-called Big Species Book (1856-58) [Species Book) that
directly underlies the published Origin. This will be followed by a
discussion of Darwin's public presentation in the Origin, followed
by some brief remarks on the divergent interpretations by Darwin's
successors.
I. THE SPECIES QUESTION BEFORE 185O
Available literature on the history of the species concept (Bachmann
1906; Uhlmann 1923; Stamos 2003 and references therein) only par-
tially clarifies the nature of the debate over organic species in the
period before the Origin. Anglophone discussions typically take as
their reference framework British, or to a lesser degree French, nat-
ural history assumed to be the main relevant background against
which to assess Darwin's own reflections. This chapter seeks to
complete some of these lines of discussion by consideration of devel-
opments in German-language natural history that were known to
I wish to acknowledge my appreciation for valuable comments on earlier versions of
this chapter from David Depew, James Barham, James Lennox, David Stamos, Robert
O'Hara, and the editors of this volume.
67
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68 PHILLIP R. SLOAN
Darwin and that played an important role in his mature reflections
on the species question.
A pre- Origin debate over the nature of organic species can be
dated from the 1750s; it followed upon the novel reflections on the
issue by Georges-Louis le Clerc, comte de Buff on (1 707-1 788) in
his Histoire naturelle, generate et particuliere (1749-67 with sup-
plements). The novelty of Buffon's innovation, first introduced in
1749, revolved around the epistemological and metaphysical shift
that Buffon introduced into the discussion of species in a form that
affected subsequent reflections in a profound way (Farber 1972; Sloan
1986, 2002, 2006).
Buffon's arguments can be positioned against a heritage of dis-
cussion that reached back to Aristotelian and Scholastic sources
and the remnants of the so-called universals problem inherited from
the medieval period (Stamos 2003, Chapter 2 and references therein).
One aspect of this heritage was the dual reference of the term species
or eidos in Greek. One employment of this term applied to the uni-
versal in thought and language, such as the universal noun "man"
or "horse." The other referred to the individualized substantial form
in the particular existent thing, for example, the specific principle
in "Socrates" or "Dobbin" that with matter constituted the existent
thing in Aristotelian metaphysics. Although these two concepts of
eidos or species were related within Aristotelian metaphysics and
epistemology, they were nonetheless distinct concepts and referred
to different domains - one to thought, language, and logic, the other
to physical reality. The use of the same Greek, and later Latin, term -
eidos or species - was not, however, accidental, nor was it the prod-
uct of conceptual imprecision. The tie between universal and partic-
ular, ultimately linking conceptual thought to the existent world of
real substances, formed a critical component of the Aristotelian the-
ory of how mind and world connect. "Man" and the specific principle
in "Socrates" are different but still intimately connected. Scholarly
research has shown that it is the meaning of eidos as form, and not
in its sense as universal, that is the primary meaning encountered
in the Aristotelian biological treatises, a point that is important for
the subsequent discussion (Balme 1962).
The positions developed as criticisms of the Aristotelian theory
of universals took the form of either "nominalism" - the claim that
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Originating Species 69
universals are only "bare names" that do not denote any shared form
or essence in things - or "conceptualism," developed particularly
in the early modern period by the English philosopher John Locke
(1632-1704) (Stamos 2003, Chapter 2 and references therein).
The development of modern rational systematics, commonly
attributed to Carl von Linne (Linnaeus) (1707-1778), involved the
development of a stabilized hierarchy of classes in the now-familiar
sequence of Kingdom, Class, Order, Genus, Species, and Variety. Fur-
thermore, with some important exceptions that cannot be explored
here, Linnean taxonomic philosophy was built upon implicit Aris-
totelian Realist foundations (Larson 1971). Within the Linnean
hiearchy, only taxa at the next-to-lowest category level were to be
designated as a "Species." Divisions below this - groups forming the
Linnean category "Variety" - were only accidental variations within
the group sharing a single form defined by the species definition.
There were no fundamental difficulties, except practical ones, in
applying this same logic to the classification of inorganic entities,
and Linnaeus himself classified minerals in the Systema naturae by
the same principles. Linnean classification can be generally analyzed
in terms of class logic and set theory (Buck and Hull 1966). In the
following discussion, I will understand the Linnean "classificatory"
or "logical" conception of a natural species as a class of particulars
that satisfy the defining necessary and sufficient criteria for class
membership at that level of the Linnean hierarchy. Such groups will
be denoted as speciesL, including within this designation similar
classificatory and logical senses that might be given to taxon or
group names at the levels of Variety, Genus, Family, and so on.
The novelty of Buffon's new program in natural history involved
a creative reinterpretation of the by-then established Linnean sys-
tem. This involved his explicit separation of the two fundamental
meanings of species - universal concept and individualized substan-
tial form - that had been connected in the Realist tradition just
outlined. Furthermore, this separation of meanings was posed by
Buffon in the form of an opposition between these two traditional
meanings of species.
Buffon's primary definition of an organic species was remark-
ably close to the conception of eidos as encountered in the bio-
logical treatises of Aristotle, and may in fact have been derived from
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70 PHILLIP R. SLOAN
Aristotle's biological treatises through Buffon's reading of William
Harvey (Sloan 1986). 1 In this sense, species refers to the individ-
ualized substantial form perpetuated through a lineage of partic-
ular individuals forming an ancestor-and-descendant relationship,
extended in time such that it renders the species enduring and even
eternal (e.g., Aristotle, De anima, II. iv. 415b 1-10). This conception
of natural species Buffon explicitly contrasted with the meaning of
species as universals, or species L , which he considered only "arti-
ficial" and "arbitrary." Buffon's "real and physical" species were,
unlike Linnean species, grounded in the material connectedness of
individuals through reproduction, either contemporaneously or as
extended in time.
We can see the novel ingredients in Buffon's species concept
in his most extended statement of 1753, subsequently given wide
currency by its verbatim republication in 1755 in the influential
article "Espece: histoire naturelle" in Diderot's and D'Alembert's
Encyclopedie ou dictionnaire raisonne:
An individual is a creature by itself, isolated and detached, which has noth-
ing in common with other beings, except in that which it resembles or
differs from them. All the similar individuals which exist on the surface of
the globe are regarded as composing the species of these individuals. . . .
However, it is neither the number nor the collection of similar individuals
which forms the species. It is the constant succession and uninterrupted
renewal of these individuals which comprises it. Because a being which
would last forever would not be a species, no more than would a thousand
similar beings which would last forever. The species is thus an abstract
and general term, for which the thing exists only in considering Nature
in the succession of time, and in the constant destruction and renewal of
creatures. . . .
It is thus in the characteristic diversity of species that the intervals in
the gradations of nature are most sensible and best marked. . . . The species
being nothing else than a constant succession of similar individuals that
reproduce themselves, it is clear that this denomination must be applied
only to animals and plants, and that it is an abuse of terms or ideas that
1 Some textual evidence supports the claim that Buffon and Daubenton recognized
these different usages in Aristotle's biological works and consciously exploited this
difference (Sloan 2002, 252 n. 25 and references therein). Appeal to recent scholarly
readings, such as Balme's (1962), is therefore warranted.
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Originating Species 71
the classifiers [nomenclateurs] have used it to designate different kinds of
minerals. (Buffon 1753 quoted in Piveteau 1954, 355-6)
As Buffon developed these concepts in the course of his Natu-
ral History, his "physical" species had both synchronic aspects -
membership in such a species was defined by relationships of inter-
fertility - and diachronic dimensions - the individual organisms
comprising a physical species were connected in time by descent
from a common source by physical reproduction. In both dimen-
sions, organisms are related by some kind of material continuity.
The identity of the species over time is maintained by the conserva-
tion of the underlying "internal mold" that underlies the reproduc-
tion of like by like (Farber 1972). Much of this sounds like Aristotle's
conception of eidos in the metaphysical sense employed in the bio-
logical treatises, even to the degree that Buffon's "internal mold"
functions much like Aristotle's substantial form in this relation.
I shall designate such "physical" species in Buffon's sense as
speciesn in the following discussion, with the subscript intended
to denote the historical and material connectedness implied in his
designation. I also include in this designation the broader concep-
tions of genre and famille in the "real and physical" sense in which
Buffon employed these genealogical meanings in subsequent vol-
umes of his Natural History, broadening his original conception of
species fixity.
The confusions in the subsequent tradition created by Buffon's
arguments were substantial. Many of his contemporaries either read
him as some kind of species nominalist, or failed to see the point of
his distinction between traditional speciesL and his new emphasis
on the ontological reality of species H . But this was not the case in the
Germanies. Through the reworking of some of Buffon's arguments
by Immanuel Kant in influential discussions initiated in his anthro-
pology lectures in 1775, a formal and epistemically grounded sys-
tematization of the distinction between species L and species H . was
introduced that reverberated through German-language life science
in the early nineteenth century (Sloan 2006 and references therein).
This was an outcome of Kant's efforts to systematize the distinc-
tion between Linnean and Buffonian projects in natural history. One
form of "natural history" - primarily the Linnean - was conceptual-
ized as a synchronic descriptive project, the "description of nature"
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72 PHILLIP R. SLOAN
[Natmbeschreibung, Physiographie), which included biogeography
and the geographical distribution of organisms. Classification within
the "description" of nature was concerned with synchronic relation-
ship rather than vertical historical genesis. To a large degree this
mapped onto the tradition of speciesL discussions.
Kant located the historical lineage dimensions of Buffonian
species H within a historical and genetic understanding of nature
(Naturgeschichte, Physiogonie). Furthermore, the distinction be-
tween these two programs was not only relevant to the concep-
tion of groups at the species level; it also extended to the distinction
between the Linnean conception of a Variety and the newly emerging
conception of Race [Rasse], given a new theoretical status by Kant's
distinctions. For Kant, a "Race" designates the group of related and
interfertile but semipermanent lineages descending from a common
source. This is a concept that is valid within the "history," but not
the "description," of nature. A Linnean "Variety" lacks these his-
torical aspects, even if it is validly employed in Linnean fashion in
the synchronic classification of forms. From these distinctions we
find a parallel terminology developing in the German biological lit-
erature that differentiated concepts valid within the "history" from
those valid in the "description" of nature. The importance of this
will emerge later.
In spite of Kant's attempts to systematize and clarify the dis-
tinctions between the referents of speciesL and speciesn and related
concepts, the historical interaction, and indeed the inevitable con-
fusion, that ensued in the early decades of the nineteenth century
among the various referents of the term "species" is evident from
the literature of natural history of this period. In this we perceive
a rich and complex interplay of these alternative species concepts,
with one body of literature continuing to interpret species in the
species L tradition, and a second body of literature, developed par-
ticularly within German philosophy of nature [Natuiphilosophie],
exploiting the concept of species H (Spring 1838). This later mean-
ing was also picked up by Hegel and given a further philosophical
foundation in his notion of the concrete universal (Stamos 2003,
Chapter 4).
This German tradition of discussion emphasized the notion
of species taxa as holistic and historical lineages constituted by
reproductive relationships, descending from a common ancestral
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Originating Species 73
source, and extended in time and space. Such species and their sub-
divisions or conglomerations [Aiten, Abarten, Unterarten, Rassen,
Gattungen) in the living world were to be distinguished from classes
of minerals or other nonbiological entities. Such species were also,
in the tradition of Buff on, designated by adjectives like "real,"
"physical," and "historical" in opposition to the "arbitrary" group-
ings of logical arrangement. The complex framework of these early
nineteenth- century debates within theoretical natural history, rang-
ing across metaphysical, epistemological, and empirical questions,
provides a complex background against which we can address Dar-
win's mature discussion of these questions in the Origin.
II. THE BIG SPECIES BOOK FOUNDATIONS
Darwin's omnivorous readings in the twenty-year period following
his return to England in October of 1836 and the commencement of
the Big Species Book manuscript in 1856 involved a wide sampling
of sources drawn from several national traditions. Well known is
the close reading and annotation of Charles Lyell's discussion of the
"species question" in the fifth (not the first) edition of the Principles
of Geology, published after Darwin's return from the Beagle voyage.
Lyell's long discussion of the species question, presented in the con-
text of a critique of Lamarck's transformism, defined much of the
"species problem" for British natural history. His discussions also
gave a specific meaning to the "reality of species" question that cen-
tered it around issues bearing primarily on what I have termed the
speciesL problems. For Lyell, the issue of the "reality" of species con-
cerned the evidence for the existence of a stable "specific character"
in spite of variations related to geography and geological changes
(Lyell 1832, 2: 18). Lyell defended the "reality" of species in his
exhaustive examination of the evidence for and against variation
beyond the limits of a fixed specific type. Darwin also encountered
some further analysis and reworking of Lyell's arguments through
his reading of William Whewell's discussion in the History of the
Inductive Sciences of 1837 (Whewell 1837, 3: 573-80).
Less well understood is the impact of Darwin's reading of
other sources, particularly those drawing on the speciesH tradition.
Commencing in 1845, following the completion of the 230-page
rough draft laying out the primary argument of the future Origin
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74 PHILLIP R. SLOAN
[Foundations], Darwin undertook an intensive period of correspon-
dence with his closest confidant, Joseph Dalton Hooker, to whom
he had shown his 1844 manuscript. These readings also took place
in the wake of the sensation created by the anonymous publica-
tion in 1844 of the Vestiges of the Natural History of Creation by
the Scottish publisher Robert Chambers, who made a sweeping case
for species transformism. As a botanist, Hooker referred Darwin to
several sources dealing with the species question as it was encoun-
tered in botany. These readings also transpired shortly before Darwin
began his intensive study of barnacles in September of 1846.
Primarily socialized as a zoologist and geologist, Darwin was now
immediately engaged with the problems of botanical classification,
issues he would then confront in a similar form in the zoologi-
cal world in his massive study of the barnacles. This sequence of
mid-i 840s readings can be followed in Darwin's Reading Notebooks
(DAR 119), in his correspondence, and also through his annota-
tions of key texts. These readings included several papers by the
botanist Hewlett C. Watson (Watson 1843, 1845), issues of the Lon-
don fournal of Botany and The Phytologist, a long review article
in French on the species question by Frederic Gerard, an article on
geographical botany by Alphonse De Candolle, and a monograph
on the species question by the German botanist Johann Jacob Bern-
hardi. In these readings we can follow an interplay between the
speciesL and speciesH concepts we have outlined earlier. Darwin's
direct encounter with speciesH discussions in these 1840s readings
added a new dimension to his reflections, and they allowed him
to draw into a creative synthesis issues from these two separable
domains of discourse. Through these readings in the botanical lit-
erature, Darwin engaged the complex issues of criteria and group
definition that beset any practical application of the species L con-
cept in botany. Similar issues were then engaged in his barnacle
studies, which involved him in a messy worldwide revision of a dif-
ficult invertebrate group [Correspondence, 5: 155-56; Darwin 1975,
101). Darwin's readings in the mid-i840S laid foundations, through
annotations and notes, to which he returned in 1856 in composing
the Big Species Book manuscript. To these 1840s readings were also
added new readings in works that had appeared during the inter-
vening period, such as De Candolle's Geographical Botany (1855)
and papers by Edward Blyth (Stamos 2007, 140-1 ). The result of this
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Originating Species 75
engagement can be discerned from a close examination of the Species
Book discussion.
The manuscript discussion opens with a commentary on the con-
fusion over the various definitions of "species" found in the lit-
erature. Much of this literature was summarized for Darwin in De
Candolle's review (Candolle 1855, 2: 107 1-8). Of all the options sum-
marized by Candolle, he sees common descent as the preferred basis
for species definition [Species Book, 96). Elaborating on this point,
Darwin cites empirical problems created by the fact that many organ-
isms - specifically, in this case, the primrose and cowslip - fit all the
morphological criteria for distinct species but are "produced from
the same stock," even though "they cannot be said to resemble
each other as much as analogous plants do, which we positively &
habitually know to have descended from a common source. Hence I
conclude, that descent is a prominent idea under the word species as
commonly accepted" [Species Book, 96). This leads him to conclude
that "the idea of descent inevitably leads the mind to the first parent,
& consequently to its first appearance, or creation" (ibid.).
Darwin then returns to a text he had read carefully and anno-
tated in the mid-i 840s, Concerning the Concept of the Plant Species
and its Application, by the German botanist Johann Jacob Bernhardi
(1774-1850). Bernhardi's short (sixty-eight-page) text displays some
implicit familiarity with the post-Kantian distinctions between
the "descriptive" and "historical" analyses of nature and the con-
cepts relevant to each we have outlined here. At least some con-
temporaries placed Bernhardi in the same tradition as the Natur-
philosoph Lorenz Oken. This context is not, however, made explicit
in Bernhardi's text, and the content of his essay is concerned
with practical classification rather than with issues of biological
theory.
His text opens with an introductory discussion of the concept of
species, which Darwin annotated in several places. This begins with
a distinction between the conception of species in logic - a "sum
of individuals which agree in certain characters" - and other mean-
ings of the term. The "logical" meaning is a "concept, which lies
at the basis of the classification of organic beings," but this defini-
tion "remains too indeterminate" because of its inapplicability in
practical natural history and its inability to capture the "extraordi-
nary changes according to the age, the time of birth, the location,
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j6 PHILLIP R. SLOAN
climate, etc." necessary to discriminate between a species [Art] and a
variation [Abait]." Required also are concepts applicable to "organic
creation and specifically to the plants "(Bernhardi 1834, 1).
In answering this difficulty, Bernhardi develops an extended argu-
ment that interweaves several issues, interfacing these with the prac-
tical problems of distinguishing between species and varieties in the
botanical world. However, these difficulties are not focused on the
standard problems of character overlap and variation, as we might
encounter in species L discussions. The difficulties instead are those
presented by the different degrees of genealogical descent. Ideally,
the general rule for defining a species would be the communality
of genealogical descent. In a passage marked by Darwin, Bernhardi
offers such a primary species definition: "One unites all individuals
into one species which have been generated up to the present from
an original stem-parent from seeds or germs" (ibid., 2).
But Bernhardi then raises several problems with this definition.
Even if descent is the desirable means of defining natural species,
problems presented by cryptogams and the difficulty of determining
sources of descent require other supplementary considerations. To
accomplish this, Bernhardi proposes consideration of the "total con-
formity in organization which must have been generated under the
same circumstances" as a needed addition (ibid., 3).
Because Bernhardi sees a range of difficulties created by different
degrees of genealogical relationship, he proposes a set of termino-
logical distinctions that are intended to capture these descent rela-
tions, which he distinguishes from "logical" usages. This requires a
new terminology. In place of the category name "Variety" he offers
"Subspecies" [Unterart), designating groups defined by fertile inter-
breeding and common descent (ibid., 4). Further degrees of genealog-
ical relationship are designated by such terms as Abort, Bastarde,
Spielart, and Abanderung. The distinctions among such subgroup -
ings are not clear-cut, but for reasons other than character overlap.
As Bernhardi comments in a passage underlined (as indicated here)
by Darwin:
As it appears essential to adopt these concepts generally, it is still not to
be denied that in many cases it can be doubtful whether one is dealing
with a Species [Art], a Subspecies [Unterart], a Variation [Abart] or a Hybrid
[Bastarde]. (Ibid., 5)
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Originating Species 77
Bernhardi's distinctions are then directly translated into more
familiar Linnean terms by Darwin. His annotations on this discus-
sion also make clearer than do his own published texts the differ-
ences between these descent-concepts and those of Linnean classi-
fication. In a marginal note on Bernhardi's definition of Abarten, he
writes " 'Abarten' a variety which does not tend to go back to parent
form." Similarly, alongside Spielaiten he writes: "' Spielarten ', those
that go back one or more generations" (Bernhardi 1834; DiGregorio
and Gill 1990, 55). And in a longer annotation at the bottom of the
next page he writes:
Unterart subspecies = doubtful races or the close species/ Abarten - hered-
itary = race for variety in animals)/ 'Spielarten' - which are herditary [sic]
for few generns [sic] - variety of DeCandolle/ Abanderung - which are not
at all hereditary - allied to Monstrosities. (Ibid., 55)
By understanding the interplay of these issues in Darwin's
thought, we can unpack several otherwise puzzling issues in his
discussion of species, and particularly the fluidity in his concept
of "variety" (Stamos 2007, Chapter 7). On the one hand, the issues
of morphological variation and character overlap, something made
strikingly evident at the practical level to Darwin through his barna-
cle work, which displayed how taxonomic distinctions of taxa at the
levels of varietiesL and speciesL were rendered difficult, and even to
a large degree arbitrary, by the overlap produced by character varia-
tion. Such variation blurred the boundaries and introduced the need
for "expert" skill and consensus among "competent" authorities as
the only means of deciding on these limits. On the other hand, as we
pursue these issues within the framework developed earlier, we see
that Darwin was drawing upon more than one tradition of discourse.
The problems created by variation for species could be reinterpreted
by the use of speciesH concepts. This combination of traditions is
strikingly apparent in the following quotation from the Big Species
manuscript:
The term 'Variety' is applied to forms often offering considerable differences,
& which can be securely propagated by buds, grafts, cuttings, suckers &c,
but which are believed not to be inheritable by seed. This class nearly corre-
sponds with "abanderungen" in Bernhardi's classification in which the form
is not hereditary or only so in certain soils,- &. likewise in a lesser degree
with his "Spielarten" in which the form tends to go back in one or more
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78 PHILLIP R. SLOAN
generations to the parent type. . . . Lastly we have the class "Race", corre-
sponding with "Abarten" of Bernhardi & with subspecies of some authors,
in which the form is strictly inherited, often even under changed conditions,-
of this class we know there are plenty under domestication, some known,
& more suspected in a state of nature, as in the geographical races of some
Zoologists. But the term subspecies is used by some authors, to define (&.
corresponds in this sense with "unterart" of Bernhardi) very close species,
in which they cannot determine whether to consider them as species or
varieties. . . . {Species Book, 98-9)
This interweaving of issues of taxonomic classification and
genealogical descent, conflating different referents for the terms
"species," "varieties," "subspecies," and "races," underlies the con-
ceptual fluidity of Darwin's discussions that we can follow directly
into the published Origin.
III. GOING PUBLIC
Presented initially as an "abstract" of his intended book, the argu-
ment of the Origin involved a drastic stripping out of the detailed
references and supporting materials from the Natural Selection
manuscript. This created a condensed, and ultimately more popu-
larly accessible, form of presentation. Arguments developed in the
manuscript with reference to specific issues or groups were rendered
universal claims by this condensation. For his critics, this also meant
that supporting documentation and detailed references to sources
were typically not present.
On the issue of species, this condensed form of presentation sub-
merged the important details in the genesis of his novel views we
have examined in the previous section. Instead, we find a compressed
discussion that is difficult to clarify. To understand Darwin's argu-
ments, I have examined the various usages of the 1,489 occurrences
of the term "species" in the first edition of the Origin (Barrett et
al. 1981). This review of word usage shows an interweaving of sev-
eral diverse meanings. Judged from these usages alone, it is diffi-
cult to defend a systematic "rhetorical strategy" thesis advanced by
some scholars - the thesis that Darwin consciously utilized different
meanings of "species" to win over adherents to his arguments -
although this may be argued on additional evidence from other texts
(Beatty 1985; Stamos 2007, Chapter 8). In some places, Darwin's
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Originating Species 79
usage is consistent with speciesL concepts, and in this context he
even affirms a kind of species realism consistent with this frame-
work, as when he speaks of "good species" or of species as "tolera-
bly well-defined objects" that "do not at any one period present an
inextricable chaos of varying and intermediate links/' meaning pri-
marily that they can be discriminated by nonoverlapping characters
[Origin, 177). We also find this context in play when he describes
how in many organisms, the issues of character variation tend to
break down such clear definitions, resulting in groups that display
"intermediate gradations" that make distinctions between species
and varieties endlessly difficult and even arbitrary (ibid., 47).
But in other places, species H meanings predominate, and it is
remarkable to see the way he has interwoven issues that arise from
these considerations with those of traditional logical classification.
Here Darwin interprets species and varieties as genealogical lin-
eages that display varying degrees of historical relationship. In such
contexts Darwin speaks, often interchangeably, of "subspecies,"
"races," and "varieties," in a diachronic and genealogical sense sim-
ilar to the way he integrated Bernhardi's discussions in the Species
Book manuscript. As we read through Darwin's central discussion
of these issues in the second chapter of the published Origin, it is
striking to see the way in which he has interwoven these different
usages in critical passages.
For example, in the central discussion of species in Chapter 2,
Darwin introduces his analysis with a description of the traditional
practical problems created by character variation that face any nat-
uralist working on preserved specimens. But remarkable in this dis-
cussion, and a claim that was startling to some of Darwin's readers
(see, e.g., Owen i860 in Hull 1973, 211), is that this practical prob-
lem facing species L concepts is then integrated, without detailed
argument, with the gradation in degrees of genealogical relationship
at issue in species H distinctions. We see how this is being done in
the following passages:
Certainly no clear line of demarcation has as yet been drawn between species
and sub-species - that is, the forms which in the opinion of some naturalists
come very near to, but do not quite arrive at the rank of species; or, again,
between sub-species and well-marked varieties, or between lesser varieties
and individual differences. These differences blend into each other in an
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80 PHILLIP R. SLOAN
insensible series,- and a series impresses the mind with the idea of an actual
passage. [Origin, 51)
This claim could still be understood as a difficulty presented
by taxonomic analysis at the speciesL level. Speciesn relationships,
however, are historical and ontological. Darwin's synthesis of issues
subtly transforms the taxonomic difficulties in one domain into evi-
dence for metaphysical ambiguities in degrees of historical descent
in the other domain:
Hence I look at individual differences, though of small interest to the sys-
tematist, as of high importance for us, as being the first step towards such
slight varieties as are barely thought worth recording in works on natural
history. And I look at varieties which are in any degree more distinct and
permanent, as steps leading to more strongly marked and more permanent
varieties,- and at these latter, as leading to sub-species, and to species . . . ;
and I attribute the passage of a variety, from a state in which it differs very
slightly from its parent to one in which it differs more, to the action of nat-
ural selection in accumulating . . . differences of structure in certain definite
directions. Hence I believe a well-marked variety may be justly called an
incipient species. (Ibid., 51-2)
By combining these two strands of species discourse into one,
Darwin created an unusual conceptual synthesis with revolutionary
consequences. At least two primary results can be seen to follow.
First, he drew novel conclusions on the degree to which the his-
torical relationships of lineages could be conceived to diverge from
an original form, utilizing data now drawn from difficulties created
by practical taxonomy. This linkage is not necessary and could be
understood in ways that would not imply such radical claims, as in
Hugh C. Watson's distinction between "book" and "natural" species
(Watson 1843).
Second,since Buffon and Kant prior discussions of the species H
concept had interpreted the historical relations of "natural-
historical" species and their subdivisions to be confined within the
limits imposed by an originating form - a moule interieur, premiere
souche, Urtyp, or archetype - that maintained a historical unity
within a common stem, even if this unity allowed some wide diver-
gences in response to environment and history. Bernhardi, for exam-
ple, never questions this fundamental unity. SpeciesH theorists in
the German tradition in the pre-Darwinian period might be species
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Originating Species 81
developmentalists, allowing some kind of saltational succession in
time of "central types" that might give rise to successive histor-
ical lineages of related forms. But they were not genuine species
transformists in the Darwinian sense, understood to mean gradual
divergence without natural limits through the slow adaptation to
changing conditions by slight character variation.
But we see that for Darwin, the difficulties raised by practical
taxonomic problems tied to species L considerations were employed
to undermine the claims for the historical unity of groups within a
common stem central to the species H discussions. In a curious sense,
Darwin is a kind of ontological realist concerning species H/ in that
for him there "really are" these lineages. But such species no longer
have historical permanence or maintain a conservative "unity of
type." Such unity is undermined by the destructive analysis flowing
from arguments centered around speciesL issues.
In the arguments of the crucial Chapter 4 of the Origin, Darwin
introduced his principle of divergence and used the well-known
branching bush diagram (frontispiece, p. ii) to illustrate how nat-
ural selection worked over time. It is remarkable to see how this
diagram functions within the framework of the issues set out here.
The diagram is introduced initially as representing no more than
the relations of individuals within species of a single genus form-
ing lesser races or "varieties." It could be read initially as a claim
about relationships between subgroups at the speciesL level: distinc-
tions between these are often difficult because of the problems pre-
sented by character variation. One could, however, represent such
intergradating horizontal relationships by geographical maps rather
than by genealogical trees, as had been done by some of Darwin's
predecessors.
But the diagram is offered as more than a depiction of species L
relationships. Its fundamental intent is to represent a temporal, and
not a spatial, relation of forms. The blurring of distinctions between
taxa designated at the variety and species levels in the species L
domain is summoned by Darwin as support for a more general argu-
ment about the blurring of the historical relations of groups. As one
quickly perceives from the few pithy pages of argument that follow,
the coordinates of his diagram are purely relative. The horizontal
lines, representing time, can represent a hundred, or thousand, or
ten thousand or millions of generations, or even geological ages.
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82 PHILLIP R. SLOAN
Similarly, the degrees of divergence illustrated by the diagram can
represent the relations of varietiesH (or, perhaps better, "subspecies"
or "races" in the German sense) within speciesn, speciesn within
generan, generan within familiesH, or any other degree of relation-
ship designated by category names applied in a genealogical sense.
And these relationships are now historical rather than horizontal.
As several recent authors have argued, although not without
some controversy, the relevant analogy for depicting these relation-
ships is that drawn from the literature of comparative philology
of this period. The comparative philologists of the time used simi-
lar branching diagrams to depict the origins and filiation of natural
languages, a tradition drawn upon by Darwin since his earliest note-
books (Stamos 2007, Chapter 3 and references therein). This linguis-
tic metaphor provided him with a model for making the following
points.
First, like natural languages, species have common origins in time
from which they have diverged by gradual historical changes, even
though all the intermediate stages of this historical development
may not have survived and must be inferred by comparative study
of contemporary languages.
Second, there is no strict requirement of monophyly - the claim
that natural groups can have only a single historical source -
although the monophyletic origins of groups is Darwin's usual pre-
sumption. The linguistic analogy explains the otherwise curious
argument in the Origin that dogs, which can all interbreed with fer-
tility, are still viewed by Darwin as probably polyphyletic, whereas
pigeons are monophyletic [Origin, Chapter i; Stamos 2007, Chap-
ter 4).
Third, the similarity of "dialects" to "varieties" or, better, to "sub-
species" in the species H sense - with many going extinct, others
leading over time to new dialects and even to new language groups
under the conditions of isolation - fits this model surprisingly well.
Fourth, the "reality" of different languages, like that of species,
can be recognized in two ways. First, they exist horizontally in a
speciesL sense, in that it is reasonably unproblematic to give defi-
nitions of natural languages in the present that discriminate these
from one another, either through "essentialist" or "cluster" defini-
tions. The distinction of French, Portuguese, Italian, and Spanish,
for example, is a real one at the present time. Second, they have
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Originating Species 83
another kind of "existence," vertically in the speciesn sense. There
is a concrete historical connection between these linguistic groups
and a common historical ancestor-language (Latin), from which they
all differ. We may also, in some cases, recognize "incipient" diver-
gences in distinguishable language groups at the present time that
may result in more fundamental subdivisions in the future.
The primary disanalogy in the linguistic model centers around
Darwin's principle of divergence - the tendency of natural groups
to diverge and fragment under the incessant Malthusian pressure of
population. This means that such groups tend to subdivide, rather
than coalesce, and to fragment rather than combine, in areas of over-
lap. It can be argued that there is nothing like this differentiating
principle operative in the development of languages, where there
are strong forces within the human social group that tend to create
unification of several linguistic traditions into a single language in
areas of overlap, or through successive stages of inclusion, such as
has occurred with English. To the contrary, Darwinian divergence
tends to "sympatric" speciation - that is, speciation without evi-
dent geographical isolation - as populations tend to subdivide single
ecological niches and develop character divergences in order to max-
imize the amount of biomass possible in a given space in response
to Malthusian pressures.
But with this important disanalogy recognized, the linguistic
model provides several points of contact for understanding the way
in which Darwin unified history and description, classification and
genealogy, in his novel synthesis.
IV. SPECIES AFTER I 85 9
Space limitations permit only a brief pointing to some select issues
that faced those trying to understand Darwin's complex species dis-
cussions during the post-1859 period. The controversies and cri-
tiques of Darwin's theory resulted in well-known modifications of
Darwin's presentation of his argument in the subsequent editions
of the Origin during the period between 1859 an d the sixth edition
of 1872 (final revision 1878). Revisions of the Origin, either minor
or major, occur in nearly 75 percent of the original text [Variorum
1959). On the issue of species, however, there are few, if any, funda-
mental changes in the argument.
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84 PHILLIP R. SLOAN
Although Louis Agassiz's quip - "if species do not exist at all, as
the supporters of the transmutation theory maintain, how can they
vary?"(Agassiz i860 quoted in Beatty 1985, 270) - exemplifies a long
tradition of those who read Darwin's arguments in the Origin as
those of a "species nominalist" (Stamos 2007, Chapter 1), at least
some influential German biological theorists clearly read him as
a "species realist" within the species H tradition, with a surprising
outcome. For example, the influential Swiss botanist Karl Wilhelm
von Nageli (1817-1891), who had been formed intellectually within
the tradition of "philosophical" natural history inspired by Lorenz
Oken's Naturphilosophie, originally conceptualized organic species
as dynamic and holistic entities united by common reproduction in
a group governed by a unifying rational Idea. In a lecture delivered
on March 14, 1853, while a professor at the University of Breisgau,
he remarked:
Individual plants do not occur purely as independent Beings by themselves.
They are at the same time also parts of a higher Totality, elements of a
general motion [Bewegung]. Because they generate new individuals, because
these propagate themselves in turn and the procreation process is repeated
continually in their progeny, there arises from this an undeterminate sum
[Summe] of plants, which is not to be considered a loose aggregate, but forms
the species, an undivided whole, which is held together by a common Idea.
(Nageli 1853 quoted in Bachmann 1906, 180)
As Darwin's Origin was transmitted and assimilated into the
German states in a scientific context heavily influenced by
Schelling's Naturphilosophie (Mullen 1964), Nageli's subsequent
reflections demonstrate how some German theorists of biology sim-
ply transformed their conceptualizations of Ideal natural-historical
species undergoing a rational "development" in time into a thesis
about concrete and ontologically real species, conceived as dynamic
holistic entities analogous to organic individuals, physically trans-
forming into new species. In a published lecture on this topic deliv-
ered in 1865 while at the University of Munich, Nageli, now a new
Darwinian convert, spoke of how species "actually die like individ-
uals [and] new species are developed once again like an individual"
(Nageli 1865, 35). Such species could be related like the branches of
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Originating Species 85
a tree, with degrees of taxonomic rank related to the recency of the
splitting of the stem.
When a plant form begins to vary, it makes first notable individual Varieties,
which are connected to one another through middle forms. ... By constant
divergence, the motion [Bewegung] passes from Species into Genera, and
these into Orders and Classes. Between the designated categories there is no
absolute difference. It is only a case of more or less. . . . The Genera and the
higher concepts are not abstractions, but concrete things [concrete Dinge],
complexes of interconnected forms which have a common origin. (Ibid.,
31-2)
A very different reading of Darwin's arguments is found in the
development of statistical and populational interpretations by the
British biometricians, represented in particular by Karl Pearson
(185 7-1 9 3 6). Originally trained in mathematics and engineering
statistics, Pearson transferred his powerful mathematical skills to
issues of evolutionary biology through his close association with
his colleague, the zoologist W. F. R. Weldon (1 860-1 906). Through
a series of landmark papers, Pearson and Weldon gave the analysis
of the species question a statistical and populational interpretation
that exploited the speciesL tradition in new ways. Species are defined
by the clustering of character measurements around a central mean,
and they constitute logical classes of individuals defined by a statis-
tical type representing the average character values. But the statis-
tical variation displayed by the character measurements in a popu-
lation renders the boundaries of statistically defined species groups
intergradating. Such groups may also be changed into new species
by direct selective pressures acting on their phenotypic characters
over time (Gayon 1998, Chapter 7). Such change was presumably
demonstrable by the use of advanced statistical methods developed
by Pearson and Weldon and applied experimentally to natural popu-
lations (Pearson 1900, Chapter 10).
Sorting out the interplay of the complex discussions of the species
question in post-Darwinian discourse, and the complexities this
interplay introduced into the philosophy of evolutionary theory,
extends beyond the limits of this chapter. It is, for example, of some
interest that Ernst Mayr traced the origins of his own species real-
ism directly to a text in the speciesH tradition (Mayr 1968). Similarly,
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86 PHILLIP R. SLOAN
the early geneticist Hugo DeVries drew upon Nageli in support of his
own claim that species constituted real "entities in nature" (de Vries
1910, 2: 589). What can be safely stated is that the issues raised by
these historical problems continue to interact in contemporary dis-
cussions among cladists, species "individualists," adherents to the
"biological" species concept, and "logicists." Gaining deeper clar-
ity about Darwin's conceptual achievement in the Origin itself is at
least one way to sort out some of these controversies.
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DAVID KOHN
Darwin's Keystone
The Principle of Divergence
Darwin chose an apt architectural image when he wrote J. D. Hooker
that 'the "principle of Divergence" . . . with "Natural Selection" is
the key-stone of my Book' [Correspondence 7: 102). In the Origin,
the fifteen-page section on divergence is placed strategically at the
end of Chapter 4 on natural selection, where it distributes the weight
between the core theory and the evidence for descent. Darwin por-
trays adaptation and the origin of species as emerging out of the
entangled plenitude of mutual relations mediated by natural selec-
tion. The principle of divergence united this ecological vision with
Darwin's complementary view that evolutionary history can be read
in the irregular branching of the taxonomic tree of life. However,
there is an irony in the historical fate of the principle. Much of
twentieth- century evolutionary biology rejected Darwin's explana-
tion of 'speciation' as muddled (Mayr 1942, 1992; Sulloway 1979;
Coyne and Orr 2004). z Yet the profound depth of ecological relation-
ships and the very diversity of life that Darwin evoked through the
principle can be understood as one of the Origin's most enduring
contributions. Moreover, the standing of contemporary approaches
to speciation that, like Darwin's, emphasize ecological factors - but
now often supplemented by moderate isolation of various kinds -
while remaining controversial, is perhaps higher than it has ever
been. 2 So 'The stone that the builders rejected has become the cor-
nerstone' (Psalm 1 18:22). For these reasons alone, it is important that
1 See Mallet's critique (2005).
2 This theme runs through several chapters of Coyne and Orr (2004). A case in point is
the controversy over speciation in cichlid fish in African lakes, where, for example,
Lake Malawi is reported to have produced over 700 species in 0.7-1.8 myr (147-56).
87
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88 DAVID KOHN
the modern reader of the Origin understand, in its own right, Dar-
win's principle of divergence and its dramatic role in his intellectual
maturation.
The nub of the principle is ecological, and here is one of its typi-
cally concise statements:
. . . the more diversified the descendants from any one species become in
structure, constitution, and habits, by so much will they be better enabled
to seize on many and widely diversified places in the polity of nature, and
so be enabled to increase in numbers. [Origin, 112)
Darwin's keystone is fashioned around the premise that more life
can be supported in an area if organisms of different types occupy
that area. His principle of divergence is an application to natural
history of an agronomic version of the idea, originating with the
economist Adam Smith, that more wealth is created where there is
a 'division of labor'. 3 However, when Darwin deployed the principle
of divergence, he always did so in conjunction with natural selec-
tion. The principle acts as an amplifier of selection. This coupling
of divergence and selection created a special case or type of natural
selection, which we may term divergence selection. This is selec-
tion where conditions favor divergent specializations among related
forms sharing a common location. Furthermore, as we will see, the
principle of divergence was also the centerpiece in Darwin's expla-
nation of the origin of new species. 4 So there is much that depends
on this principle.
Like natural selection itself, divergence selection is not a uni-
tary idea, but rather a complex argument. Before I examine that
argument, I will first consider the structural role of divergence in
3 Darwin was familiar with Milne-Edwards (1844; see Ospovat 1981), who treated
the specialized organ systems of animals as a division of physiological labor, but
his own agronomic use is closer to that of Smith.
4 As Mallet (2005, 106) shows, the persistent erroneous view (e.g., Coyne and Orr
2004, 1-2) that Darwin did not explain the origin of new species in the Origin
traces to Mayr's disapproval of Darwin's explanation (Mayr 1942). I have avoided
the term 'speciation' because Darwin did not use a one-word term, except for the
infelicitous 'specification'. It is particularly important not to use the anachronisms
'phyletic', 'sympatry' (Poulton 1904; see Mallet 2004, 442), or 'allopatry' (Mayr 1942,
148-9) because they obscure what was important to Darwin. For this reason, I am
introducing the term 'divergence selection', which is not part of the literature, in
order to discuss Darwin's distinctive treatment of the origin of species and avoiding
the increasingly common modern term 'divergent selection'.
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Darwin's Keystone 89
the Origin. I will then return to Darwin's argument for divergence
selection and compare it to his other selection types. Finally I will
discuss how the principle of divergence fits into the story of Dar-
win's intellectual development. There I will show that this special
amplification of selection, which emerged only once Darwin had
effectively set to work writing the Origin, constitutes the culminat-
ing move in a major repositioning of his understanding of evolution.
For in the principle of divergence we see the replacement of Darwin
the transformist geologist, who first puzzled over 'the stability of
species' aboard HMS Beagle (Kohn et al. 2005 ) ; by Mr. Darwin of the
Origin, who made ecology the keystone of evolution.
Darwin not only inserted the principle of divergence selection
right after his core argument, he also placed it before the nine chap-
ters where he presented his massed evidence for descent. In this
second part of the Origin, he reinterpreted much of natural history -
both subject areas and dominant themes - translating them into
evolutionary terms; and where possible, he applied natural selection
to effect the translation. 5 Darwin argued that evolutionary descent
produced a divergent pattern of relationships consistent with the
branching conception of systematic relations, which had already
incorporated embryology and comparative anatomy into a common
framework in the 1840s and 1850s (Ospovat 1981). But he insisted
that evolution was more than just consistent with the branching
tree of life; he tried to show how key concepts and patterns in each
natural history discipline conformed to the expectations of diver-
gent evolution. Thus, at the intersection between geographical dis-
tribution and systematics, Darwin projected onto a diagram of the
evolving tree of life, numerical patterns like the high proportion of
varieties per species in wide-ranging groups. The result was 'a lit-
tle fan' of competing and diverging incipient varieties that evolved
into species, and eventually gave rise to 'dominant' wide-ranging
genera [Origin, 116-26; Browne 1980). Likewise, it was the pattern
of 'aberrant' groups with very local distributions that Darwin trans-
lated as relicts of past extinction, where divergent evolution had
been terminated. In embryology, it was 'community in embryonic
structure' that 'reveals community of descent' [Origin 1859, 449; see
5 See Nyhart, this volume, who also found 'translation' an apt term.
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90 DAVID KOHN
Nyhart, this volume). 6 In systematics itself, encompassing morphol-
ogy and comparative anatomy, it was through evolutionary diver-
gence that Darwin accounted for the very heart of the natural system,
the hierarchical concept of groups arranged within groups. When
one considers how many potent natural history concepts Darwin
tethered to evolution through divergence, one sees how profoundly
these translations were woven into the binding structure of the
Origin.
THE DOUBLE ARGUMENT OF DIVERGENCE
Selection for Darwin always amalgamated the origin of adaptation
with the origin of species. Nowhere is that clearer than in the Origin
section on the principle of divergence. Here I will discuss the struc-
ture of the argument for divergence as an adaptive mechanism, and
in the next section I will consider how Darwin applied this argument
to the origin of species.
Divergence as Adaptive Mechanism and Selection Type
Divergence selection combined two concepts: the principle of diver-
gence and natural selection. Operating together, they constitute a
claim for the regular existence in nature of conditions of selection
and a dynamic process that leads to a divergence of forms. Darwin's
argument is that the ecological situation described by the principle
of divergence is itself adaptive and hence that individuals are subject
to selection. As we've seen, the principle is an agronomic expression
of Adam Smith's theory. Indeed, Darwin first wrote the division of
'land' and then substituted the division of 'labour' (Kohn 2006, DAR
205.5: 171). In transforming Smith's concept, he argues that 'mutual
relations' - the complex of other creatures, with each group 'striving
against the other' - forms an adaptive situation within which selec-
tion occurs. So the division of labour is concomitant with this strug-
gle. It is simultaneously treated as a selective advantage and as the
6 Ospovat (1981) shows the link in the literature between the theory of embryonic
recapitulation and 'the branching conception of life', but he says Darwin abandoned
recapitulation in the 1840s (152,).
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Darwin's Keystone 91
result of the selection that goes on within the context of other strug-
gling species. Since the 'land' - the operant image is plants growing
in an agricultural field or pasture - contains resources distributed
throughout its extent, these can be most efficiently exploited by
plants of different types drawing on water and nutrients distributed
at varying densities in different areas and at different depths. Diver-
gence selection, through the struggle that it encompasses, produces
the specialized adaptations that can divvy up the land.
It is noteworthy that the correlative of 'more' life being sustained
is that more dry weight of pasturage can be produced. And it is
tempting to think that Darwin, in applying this concept to 'nature',
was drawing on an idea that ecologists later called 'biomass'. But
no doubt in Darwin's own time, the source for these ideas is agri-
cultural chemistry and agronomy. It is the world of Liebig and crop
rotation and the experiments that were being pursued by the Duke
of Bedford's gardener, George Sinclair, whose work Darwin studied
[Natural Selection, 229; Origin, 113).
To this premise Darwin adds the further premise, elaborated ear-
lier in Chapters 3 and 4, that selection leads to adaptation. Here
Darwin also draws implicitly on an important idea about variation,
which distinguishes his 1844 "Essay" from the Origin. In 1844,
Darwin believed that there was a limited amount of variation in
nature [Foundations-, Ospovat 1981). But by the time of the Origin,
he was able to draw heavily on the assumption expressed in Chapter
2 ("Variation under Nature") that species have a great deal of indi-
vidual hereditary variability. With abundant variability to act on,
natural selection, and particularly divergence selection, would be a
strong force. In this situation, ( 1 ) there will be an adaptive advantage
favoring the selection of different forms to exploit different aspects
of the 'land', and (2) this situation will favor selection of the most
extreme - that is, the most divergent - forms. The resulting com-
pounding of specialized forms, though produced by natural selection,
is achieved through the avoidance of direct struggle. This vision is
'ecological' in that the key condition of each form's existence is not
just its ability, say, to absorb water from soil, but the more special-
ized ability to find water at a depth to which another form does
not penetrate. So, as Darwin stressed, the key conditions of exis-
tence are the 'mutual relations' of different forms. With this insight,
Darwin transformed a geologically entrained grasp of the overall
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92 DAVID KOHN
process of evolution, which was both slow and two-dimensional,
into one that stressed multidimensional biological interactions over
physical causes.
Darwin concluded the Origin contemplating an 'entangled bank,
clothed with many plants of many kinds' (489), an image of ecolog-
ical richness framed in language he first used in the fiords of Tierra
del Fuego, and to which he returned only in the final drafting of the
Origin (Kohn 1996). The principle of divergence, also a late devel-
opment in his conceptual vocabulary, gave the entangled bank its
scientific undergirding; and in attempting to explain why there is a
diversity of species, Darwin broached some of the most fundamental
issues of evolutionary ecology.
Entangled Divergence and the Types of Selection
As I have suggested, the principle of divergence contributes to a
distinctive category of selection. The result of that selection, a com-
pounding of mutual relations, is summed up, as just noted, in the
ecological vision of the 'entangled bank', that beautiful local image
Darwin used to evoke the sublime global dynamic, which formed
a significant part of the 'grandeur' that he saw in the evolutionary
'view of life' [Origin, 489-90). To be clear, Darwin speaks of the prin-
ciple and natural selection as separate concepts [Origin, 116), and he
never went so far as to coin the term 'divergence selection' in paral-
lel to 'natural', 'artificial', and 'sexual' selection. Nevertheless, it is
instructive to postulate a 'divergent' selection because we can then
compare its powerful adaptive argument for the origins of diversity
to that deployed in Darwin's named forms of selection, especially to
the most fundamental of these: natural and artificial selection.
Unlike natural selection itself, which emerged in 1838, in cre-
ative opposition to the systematic selection that Darwin knew was
practiced by breeders (Kohn 1980), the principle of divergence was
developed in the 1850s, long after Darwin had become accustomed
to presenting natural selection as analogous to artificial selection.
In fact, the divergence selection argument significantly mirrors the
structure of artificial selection in a way that natural selection does
not. To see this, it is most important to bear in mind that one feature
of natural selection differs fundamentally from artificial selection.
In the Origin, Darwin considered natural and artificial selection to
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Darwin's Keystone 93
be analogous phenomena, but they were not identical. Whereas arti-
ficial selection posits the intelligence of a human selector who picks
variants in order to produce results, in natural selection there is
no selector - no external intelligence. Rather, adaptive 'direction'
results from the intersection of two independent natural processes:
hereditary variation and changing environments. Natural selection
describes a natural process. The link between variation and environ-
ment in natural selection is the struggle resulting from Malthusian
population pressure. This too is a natural process and utterly dif-
ferent from the workings of artificial selection. There is a weak
analogy between an intelligent external selector who literally picks
variants and a struggle among variants. But at their cores, the anal-
ogy crumbles: 'intelligent external selector' is irreducibly different
from 'competitive struggle'.
How do these distinctions play out in the compounding interac-
tions underlying the principle of divergence? True, there, Darwin
does depend on Malthusian pressure:
And we well know that each species and each variety of grass is annually
sowing almost countless seeds,- and thus, as it may be said, is striving its
utmost to increase its numbers. [Origin, 113)
Undoubtedly, natural selection's struggling individuals undergird
the dynamics of this process. But Malthusian pressure is not the sole
focus. Rather, it operates to enforce the particular selective force at
play, which is the advantage that Darwin believes accrues to the
most different, or extreme, varieties:
Hence, if any one species of grass were to go on varying, and those varieties
were continually selected which differed from each other in at all the same
manner as distinct species and genera of grasses differ from each other, a
greater number of individual plants of this species of grass, including its
modified descendants, would succeed in living on the same piece of ground.
{Origin, 113)
What we see here is a multiplication of the forms that can occupy a
shared territory because of the action of some agency. 7 What is this
agency? Ultimately, it is the presence of other species competing for
7 See Depew, this volume, on agent versus agency.
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94 DAVID KOHN
the same resources, which becomes clearer and eventually explicit
in succeeding passages:
Most of the animals and plants which live close round any small piece of
ground, could live on it ... , and may be said to be striving to the utmost
to live there,- but, it is seen, that where they come into the closest compe-
tition with each other, the advantages of diversification of structure, with
the accompanying differences of habit and constitution, determine that the
inhabitants, which thus jostle each other most closely, shall, as a general
rule, belong to what we call different genera and orders. [Origin, 114)
We see the same emphasis on other competing species when Darwin
summarizes how his principle produces adaptive divergence:
After the foregoing discussion, . . . we may, I think, assume that the modified
descendants of any one species will succeed by so much better as they
become more diversified in structure, and are thus enabled to encroach on
places occupied by other beings. [Origin, 116)
In these three examples - and the second one reflects an exclusion
experiment conducted by Darwin at Down [Experiment Book, DAR
1 5 7a: 5) - divergence arises from intraspecific competition nested
within, or going on simultaneously with, interspecific competition.
From the point of view of the individual, it may all be natural selec-
tion. But in terms of divergence selection as a type of selection, by
imposing an interspecific level on top of the competition going on
within a species, Darwin effectively introduced the natural equiva-
lent of an external selector. That agency plays a role analogous to
that of the intelligent selector of artificial selection. Of course, it
is not the intelligence or intent, but rather the externality of the
selector that counts in this creature-on-creature class of selection.
In his treatment of divergence, Darwin had, in fact, found a strat-
egy for expressing natural selection that was strongly analogous to
artificial selection. Darwin made a similar move when he developed
sexual selection in The Descent of Man. There, females, typically,
are the external selectors, and the result is gaudy or pugnacious -
but healthy - males. There too, the selection is creature-on-creature.
Both these forms of selection extended the explanatory domain of
natural selection by structurally mirroring artificial selection. In the
case of divergence selection, the result was the 'more' in 'more life
can be supported' - it was the abundance and diversity of nature.
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Darwin's Keystone 95
Divergence and New Species
In the Origin, the principle of divergence was essential to Darwin's
account of how new species are formed because that gave him the
means to account for evolutionary branching. This species-forming
aspect of divergence flows directly out of its function as an adaptive
mechanism. As we have seen, the adaptive argument drew heavily
on the assumption (1) that there is much variability in species. To
make the link to the origin of species, a further assumption about
variation is added: (2) varieties are incipient species. For Darwin,
individual hereditary variation and varieties are different segments
in a continuum of species variability. Individuals at each stage are
subject to selection. The most important consideration here is that
while varieties are incipient species, Darwin also thought of individ-
ual hereditary variants as if they were incipient varieties. 8 Continued
selection could traverse the continuum from individual variation to
divergent varieties and divergent species.
Yet a further assumption was critically important, namely: (3)
incipient species could develop by divergence selection without
dependence on geographic isolation. Darwin held this view despite
his clear recognition that crossing in a sexually reproducing species
would ordinarily be expected to swamp the new variations that were
at the base of this system. Darwin's first assumption - the abundance
of variation - was a sine qua non for accepting the third, counterin-
tuitive assumption that swamping would not overpower divergence
selection. Since the plenum of variation allowed Darwin to posit
that selection could be an intense and constantly operating force,
When not under selection, individual differences merely 'fluctuate'. The term 'vari-
ety' included marked varieties, geographic varieties, and races. Very rarely Darwin
uses 'variety' where context shows he means 'individual hereditary difference',
for which he has been severely criticized (Mayr 1992, 345-8). However, one can
readily work out Darwin's intention from context. Darwin would probably not
have confused his contemporaries, who even wrote of hybrids as varieties. There
does not seem to have been a term like 'variant' available. So when Darwin uses
'variety' where moderns would use 'variant', it was probably to avoid a lengthier
locution like 'individual difference'. A similar easily penetrated cloud of confusion
surrounds the word 'variability', which today generally refers to individual differ-
ences in a population, but which for Darwin could, in addition, include the varieties
in a species. Again, attention to context usually clarifies Darwin's intended, self-
consistent meaning.
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96 DAVID KOHN
the more variation, the larger the scope of action for selection and
also the more likely that it would be sufficient to obviate the need for
isolation. Here we have to clarify an additional assumption, again
concerning variation, which served to reinforce the independence
of divergent species formation from isolation. As we have seen, for
Darwin (4) the source of hereditary variation was always the con-
ditions of existence. Indeed, he rejected the suggestion that varia-
tion is a spontaneous product of the reproductive system [Origin,
131). But, as we have also seen, with the elaboration of the principle
of divergence, Darwin's emphasis shifted from physical (geological)
conditions to mutual (ecological) relations as the primary source of
hereditary variation. The more the principle of divergence worked
to complicate the mutual relations among species living together,
the more variation became available for the further refinement of
adaptations. Thus the principle of divergence had the quality of a
self -generating force strong enough to overpower crossing. Selection
triumphed over sex to create new diverging species.
islands versus continents. We may well ask, why was Darwin
so concerned to exclude isolation? Here there are more assumptions
to clarify, this time coming from geographic distribution and geol-
ogy. We need to consider how Darwin's mechanism worked in the
context of the patterns of geographic distribution that he thought
most consistent with evolutionary expectations about the origin and
extinction of species and higher groups. It is here, finally, that 'mech-
anisms' would meet taxonomic trees.
To appreciate this, we need to recall that until he worked through
divergence, Darwin had basically three models of species production,
namely: (1 ) a linear continental model in which new forms gradually
depart from an ancestral form; (2) a model of geographic replacement
by representative species, when moving along a continental tract -
as he had witnessed in South America; and (3) a geographic isolation
model, where endemic species form, particularly on archipelagos.
While island isolation could account for divergent species, by the
time he wrote the Origin, Darwin did not consider islands to be the
principal loci of new species (Sulloway 1979). In the ample discus-
sions of geographic distribution in South America and the Galapagos,
both during and after the Beagle voyage, Darwin was always con-
cerned to arrive at a global interpretation of species distribution.
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Darwin's Keystone 97
And once he became a transformist, that meant a globally applica-
ble explanation for the formation of species. In the 1844 "Essay,"
this was resolved by the fact that Darwin thought of archipelagos as
incipient continents [Foundations, 189). If continents were formed
by the fusion of islands, then geographic isolation could indeed func-
tion as a primary condition for all species formation. Species formed
on separate islands would be distinct from each other when the
islands fused. But with time, Darwin dropped this view and was left
convinced that island isolation was a special case. 9 Only continents
contain enough species to be relevant, and so continuous ranges had
to be the primary sites of action. So Darwin developed a divergent
continental model that could explain species formation without iso-
lation. In its intellectual lineage, this model harkens back to the
representative species model of the Beagle and the immediate post-
voyage notes. But now intense divergence selection was focused on
the ecologically distinctive stations within a 'whole country'. These
areas he understood to be occupied by wide-ranging species capa-
ble of bridging the relatively minor barriers to migration, but also
capable of adapting to diverse situations.
the divergent continental model. At its core, the continental
model is nothing but a restatement of the idea that a divergence of
varieties - and ultimately of species and genera - arises through the
action of the principle of divergence and natural selection. At the
end of the divergence section, Darwin illustrated how his continen-
tal model worked by means of a branching diagram - famously, the
only figure in the Origin. But to understand his explanation, we need
to be aware that while thus far we have treated divergence selection
as a pair of related arguments situated in the natural selection chap-
ter of the Origin, as a matter of fact Darwin tucked a rather massive
9 It is important to realize that Darwin does not deny that isolation can be important
in making species, as for example in the Galapagos. But it was crucial for him to
show that species could form without isolation, essentially by selection alone. Then
it became a matter of relative importance, as he puts it in Natural Selection (254):
'In this way, I think, isolation must be eminently favourable for the production
of new specific forms. It must not, however, be supposed that isolation is at all
necessary for the production of new forms; ... I do not doubt that over the world
far more species have been produced in continuous than in isolated areas. But I
believe that in relation to the area far more species have been manufactured in, for
instance, isolated islands than in continuous mainland.'
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98 DAVID KOHN
body of evidence in support of divergence into Chapter i [Origin,
53-8). Between 1854 and 1858, he tabulated the number of species
per genus and the number of varieties per species in numerous tax-
onomic works. The analysis was based mostly on regional floras,
such as that by Boreau (1840), which identified all the plants in the
center of France to the species, subspecies, and variety level. The
'botanical arithmetic' analysis (Browne 1980; Parshall 1982) Darwin
performed on such monographs supported his key assumption that
varieties are incipient species, whose surviving descendants produce
diverging lineages. For example, Darwin thought he found that large
genera, which obviously have many species, tend to have species that
are large, that is, species having 'significantly' more varieties than
do small species. Browne and Parshall show how Darwin ran into
serious methodological problems requiring lengthy recalculations.
Indeed, Parshall has shown that the analysis doesn't stand up to
modern statistical analysis. Nevertheless, Darwin, though shaken,
remained convinced. Here are the principal conclusions drawn from
this analysis, as Darwin employed them to set the stage for his con-
tinental model of divergence (see diagram, this volume, p. iv).
The accompanying diagram will aid us in understanding this rather per-
plexing subject. Let A to L represent the species of a genus large in its own
country,- ... I have said a large genus, because we have seen in the second
chapter, that on an average more of the species of large genera vary than of
small genera,- and the varying species of the large genera present a greater
number of varieties. We have, also, seen that the species, which are the
commonest and the most widely-diffused, vary more than rare species with
restricted ranges. [Origin, 1 16-17)
From here Darwin proceeds to lay out how divergent 'lines of
descent' will arise from the application of the principle to Species A:
Let (A) be a common, widely-diffused, and varying species, belonging to
a genus large in its own country. The little fan of diverging dotted lines
of unequal lengths proceeding from (A), may represent its varying off-
spring. . . . Only those variations which are in some way profitable will be
preserved or naturally selected. And here the importance of the principle of
benefit being derived from divergence of character comes in; for this will
generally lead to the most different or divergent variations (represented by
the outer dotted lines) being preserved and accumulated by natural selection.
[Origin, 117)
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Darwin's Keystone 99
The discussion continues by describing how this first branch point
will only be reinforced over time.
When a dotted line reaches one of the horizontal lines, and is there marked
by a small numbered letter, a sufficient amount of variation is supposed to
have been accumulated to have formed a fairly well-marked variety, such as
would be thought worthy of record in a systematic work. [Origin, 117)
Much of the remainder of the diagram discussion is devoted to
extrapolating further up the hierarchy to species and genera by reiter-
ation of the same process. Darwin leads us to imagine the growing,
branching tree over hundreds of thousands of implied generations
as we envision 'creations', struggles, and extinctions at all levels of
life's hierarchy.
It is important to recognize, however, that Darwin offers no addi-
tional scenario for the creation of new species than the one we have
discussed. Divergence as we have depicted it here is in fact his one
and only explanation of how new species are made.
However, he does invoke extinction to show how this counter-
vailing process prunes the branching tree so that together diver-
gence and extinction account for the characteristic shape of the tree
[Origin, 122, 124-5). Extinction takes a number of forms, including
the extinction of parental forms, extinction of competing varieties
derived from the same parent, and extinction by virtue of expansion
into the territory of closely related species - that is, the extinction of
intermediate forms. In his discussion of extinction, Darwin supple-
ments divergence with an important corollary of natural selection.
Competition is most intense among organisms that are most alike. It
is here, crucially, that the old linear continental model, which only
explained a new form extinguishing its parent, is superseded in the
divergent continental model - itself the successor cum descent and
selection to the representative species of the Beagle, where incipi-
ent varieties come into multiple struggles that lead to extinction.
Hence, Darwin accounts for a genuine divergent splitting of species
and lineages. Thus the model has two phases: (1) divergence selec-
tion - encompassing (a) the principle of divergence and (b) natural
selection - which is followed by (2) subsequent battles to extinction
of parent, sibling, and intermediate forms. These battles of extinc-
tion are not inherently dependent on, or produced by, divergence
selection. It is just that as a by-product of phase 1, new forms are
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100 DAVID KOHN
faced with parents, siblings, and intermediates. Hence, the opportu-
nity for phase i extinction arises. And this separates Darwin's 'lines
of descent'.
So it was that Darwin translated the nexus of geography and sys-
tematics into evolutionary terms. As we have already seen, Darwin
drew on Adam Smith's political economy for the principle of diver-
gence, just as he had drawn on Malthus for natural selection. But
as Darwin leads us through his diagram, we see the shadow of two
other cultural themes. First, there is Victorian improvement:
The modified offspring from the later and more highly improved branches
in the lines of descent, will, it is probable, often take the place of, and so
destroy, the earlier and less improved branches: this is represented in the
diagram by some of the lower branches not reaching to the upper horizontal
lines. [Origin, 119)
'Improvement' is used dozens of times in the natural selection chap-
ter. We have shown that Darwin's idea of divergence is linked to
agronomy. So while agricultural improvement could be one form
of improvement implicit here, perhaps the fundamental source is
Darwin's sense of contingent progress. It can only have been the cul-
tural presumptions of an Englishman during the heyday of empire
that led Darwin to conclude the divergence section thus:
We have seen that it is the common, the widely-diffused, and widely-ranging
species, belonging to the larger genera, which vary most; and these will tend
to transmit to their modified offspring that superiority which now makes
them dominant in their own countries. Natural selection, as has just been
remarked, leads to divergence of character and to much extinction of the
less improved and intermediate forms of life. On these principles, I believe,
the nature of the affinities of all organic beings may be explained. [Origin,
119, my emphasis)
The branching diagram is the final elaboration of divergence and the
climax of the natural selection chapter. And here Darwin conveys a
sense of evolution's dynamism by portraying advancing and diverg-
ing lines of superior forces that conquer, dominate, and eliminate
inferiors. Inevitably, he was tapping deeper and darker inclinations
in himself and in his audience to transform the static image of a
tree into one of struggling combatants on the march. Darwin passed
over a line here. It was one thing to instruct the reader, as he does in
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Darwin's Keystone 101
Chapter 3, to honestly see the struggle constantly going on beneath
the face of nature, 'bright with gladness' [Origin, 6i } see Kohn 1996).
But it was another matter to sound the note of triumphal superiority
we hear as the branching diagram scenario unfolds. That would have
consequences.
Development of the Principle of Divergence
In his Autobiography (120-1), Darwin remembered divergence as
something he had 'overlooked' until 'long after I had come to Down'.
Indeed, the principle of divergence developed between 1854 and 1859
during the writing of Natural Selection and the Origin. Although
divergence is an application of natural selection, one looks in vain
for texts on divergence in the aftermath of Darwin's discovery of
selection in 1838. The closest he got (Schweber 1980; Kohn 1980) is
expressed in Notebook E:
The enormous number of animals in the world depends, of their varied
structure & complexity. - hence as the forms became complicated, they
opened fresh, means of adding to their complexity. [Notebooks, 422, E, 95)
Although the island and continental models of species formation
in the 1844 "Essay" would be important in the 1850s, we can see
why divergence itself was 'overlooked' at that stage. Since in 1844
Darwin viewed hereditary variation as dependent on slow geological
change, he had to concede that there is little variability in nature.
The opening paragraph of the 1844 "Essay," Chapter 2, states: 'Most
organic beings in a state of nature vary exceedingly little . . . ' [Foun-
dations, 82). Ospovat (1981) saw the implications: the scope of nat-
ural selection must also be severely limited. However, if we look to
the end of this paragraph, we can go a step further than Ospovat. For
it seems that Darwin already glimpsed the difficult path he would
follow to solve the problem of limited variability:
The amount of hereditary variation is very difficult to ascertain, because
naturalists (partly from the want of knowledge, and partly from the inherent
difficulty of the subject) do not all agree whether certain forms are species
or races. [Foundations, 82)
In fact, in 1844 Darwin concluded, we don't know how much vari-
ation there is because the naturalists who describe species have not
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102 DAVID KOHN
systematically recorded variation. The solution, which he pursued
after completing his South American geology books in 1846, was
to undertake his own taxonomic study and an empirical survey of
variability in a major natural group.
This brings us to Darwin's monograph on barnacles, which
Hooker helped initiate in 1846 after earlier challenging him to
'minutely' describe many species to earn 'a right to examine the
question of species' [Correspondence, 3: 253). The dilemma of lim-
ited variability and consequent weak natural selection was a pal-
pable scientific problem that forced Darwin to delay - that is,
intentionally to avoid - premature publication of his theory 10 But
if we look at the attention Darwin devoted to recording levels
of variability beyond those required to define good species and
'well defined' varieties, it becomes clear that the barnacles solved
Darwin's problem during the 1844-54 delay. For example, in a typ-
ical Darwin species description such as that for Lepas fascicular is,
he first recognized two taxonomic varieties, Donovani and Villosa,
each distinguished by a few well-defined characters. Thus far his
description is in the high-level 'lumping' tradition. Detection of
the natural cleavages within and between species depended on the
requisite knowledge of species that Hooker considered 'philosophi-
cal' (Endersby 2008). But something more is afoot that was not at all
envisioned by Hooker's challenge. For Darwin adds a section to his
description called 'General Appearance', which begins:
Capitulum highly variable in all its characters,- thick and broad in proportion
to its length, but the breadth is variable, - in some specimens, the capitulum
being longer by one-fifth of its total length than broad; in others, one-fifth
broader than long. (Darwin 1851-54, 1: 93)
Darwin recorded such individual variability in more than one quar-
ter of the species he described in 185 1. Three years later, in volume
two of Living Cirripedia, he had observed so much variability that he
simply summarized this class of variability for each genus. Thus did
Darwin gather the evidence for a solid conviction in the plenitude
Van Wyhe (2007) cavalierly dismiss weighty evidence that Darwin avoided publi-
cation and stressed instead that Darwin was merely too busy to begin his species
book (p. 177).
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Darwin's Keystone 103
of natural variability that would save natural selection and unleash
the thinking that led to the principle of divergence. 11
Upon completing the barnacles monograph in September 1854,
Darwin's delay was over. He set to work sorting his notes on species
[Correspondence, 5: 537). Drafting chapters began only in May 1856,
but by November 1854 the true writing of the Origin had already
started with an outpouring of new notes. 12 These show that the fol-
lowing simplifying assumptions characteristic of divergence - and
familiar from our discussion in the first part of this chapter - were
already then in place and may have been brewing, along with the
plenitude of variation, during the barnacle period: (1) new species
forming in continuous 'regions' with varying habitats is the cen-
ter of his attention, and (2) the necessity of geographic isolation is
repudiated:
<<If the region will support so many Composite, what ever genus, has
sported & shown its adaptation is the most likely to yield more forms. >>
[No doubt here comes in question of how far isolation is necessary, & I shd.
have thought more necessary than facts seems to show it is. - ] (Kohn 2006,
DAR205.9: 303-4)
By November 1854, divergence as an 'overlooked' problem to be
solved also first came into focus, in terms remarkably analogous to
those recollected in the Autobiography.
We include all in class, as <<in>> Crustacese, which are connected, but
yet which no definition will define, - a proceeding explicable on descent. -
(Kohn 2006, DAR 205.5: 148)
11 Darwin (1851-54, 2: 155). This interpretation does not sustain Mayr (1992), Sul-
loway (1979), and Schweber (1980), who apparently did not see the empirical
survey-of -variation dimension of the barnacle work. See also Browne (1980, 72, nn.
44-6), who says these authors held that Darwin's 'interest in varieties attracted
Darwin's attention away from individual variations' .
12 The standard biographical accounts underestimate the autonomy and momentum
of Darwin's scientific effort during this period as revealed in his notes. Although
Darwin wrote on May 14, 1856, 'Began by Lyells advice writing species sketch'
(Pocket Diary, Correspondence, 6: 522), Lyell's urgings only ignited the fire Darwin
had by then carefully prepared.
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104 DAVID KOHN
Moreover, Darwin already sees that in order to solve his problem he
needs to formulate a specific explanatory principle:
. . . For otherwise we cannot show that there is a tendency to diverge (if it
may be so expressed) in offspring of every class . . . (Kohn 2006, DAR 205.5:
149)
Thus 'a tendency to diverge' is the first in a series of synonyms
that ended in March 1857 when he coined the phrase 'principle of
divergence' in the first draft of Natural Selection, Chapter 6.
In the same passage, we see Darwin link his search for an explana-
tory principle with field observations:
It is indispensable to show that in small &. uniform areas there are many
Families & genera. For otherwise we cannot show that there is a tendency
to diverge . . . (Kohn 2006, DAR 205.5: 149)
In the following summer, Darwin and the children's nurse supplied
the 'indispensable' data by counting plant species as a measure of
diversity in Great Pucklands - a field adjacent to the Sandwalk.
Meanwhile, from November 1854 onward Darwin initiated another
form of empirical support for his exploration - botanical arithmetic
calculations. These were not directly relevant to defining the
'tendency to diverge'. 13 However, they were critical as Darwin now
articulated the divergent continental model of species formation.
Speculating on the results of his calculations on aberrant groups
'<<becoming>> extinct' brought Darwin to identify large, wide-
ranging genera as the key evolving groups and to seize on local
circumstances as the site of species origin (Kohn 2006, DAR 205.9:
303-5). But, to truly examine local circumstances, Darwin scales
down from geographical regions and their abstract 'stations' to
'small &. uniform areas' such as his neighbor's thirteen-acre field
(Kohn 2006, DAR 205.9: 303-5 vs. DAR 205.5: 149). Then from 1855
onward he further delimits his focus until he has defined a classic
experimental model: a patch of ground a few square feet in area
(Kohn 2006, DAR 205.2: 119 begins the process). Thus botanical
arithmetic and field experiments creatively intersected, as Darwin
13 Perhaps because Browne's brilliant study focused tightly on the botanical arith-
metic, she was led to a far-too-late date for the principle of divergence after March
1857 (1980, 53, 73).
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Darwin's Keystone 105
sought sufficient magnification to think through the connection
between the principle of divergence and natural selection.
Notwithstanding these two empirical projects, the main articula-
tion of the principle occurs in speculative, synthetic notes. Thus in
November 1854, three key pieces of the problem's solution were
already explicit: (1) mutual relations (indirectly) cause variation
(Kohn 2006, DAR 205.9: 260) - thereby loosening the link between
origin and geology and thereby also accounting for the new plenitude
of variation; (2) divergence in the absence of isolation brings Darwin
to emphasize intense selection (Kohn 2006, DAR 205.9: 303-4); and
(3) most important, Darwin invokes the division of labor by this
early date, a point missed by Ospovat (1981) and Browne (1980):
There is no law of Progression, but times wd. give better chance of sports,
&. allow more selection,- &. all the organisms thus living an advantage, - a
<<free>> competition of labour, - the result wd be more complicated &.
more perfect; (Kohn 2006, DAR 205.9: 250, my emphasis)
Thus, we already see the core of the principle of divergence: the
ecological application of Adam Smith's division of labor. 14 In the
Origin that is expressed as the idea that more life can be supported
where divergent forms occupy a common area. Here Darwin comes
close, but does not quite make that connection. It would be just
three months later, in January 1855, that Darwin clearly stated the
ecological equivalent of the division of labor:
On theory of Descent, a divergence is implied &. I think diversity of struc-
tures supporting more life is thus implied. (Kohn 2006, DAR 205.3: 167)
This is the culmination of a first rich, and hitherto insufficiently
appreciated phase of Darwin's intellectual development (November
1 85 4-January 1855). During this highly compressed period, the prin-
ciple of divergence per se was formulated (Kohn 1985).
What remained, however, was for Darwin to make explicit the
link between divergence and selection that we see in the Origin,
14 Here Darwin disavows an 'innate tendency to progress', as he also did in 1839
[Notebooks, 422, E,95: 'no <<NECESSARY>> tendency in the simple animals to
become complicated' ). But he does believe that 'complexity' and 'perfection', which
we can roughly associate with a Victorian notion of progress, are consequences of
natural selection and the nascent principle of divergence.
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106 DAVID KOHN
where the principle and natural selection work conjointly to pro-
duce new, diverging forms. This happened in the middle of a new
phase that began in June 1855 and ended in March 1857, when Dar-
win wrote the conceptual heart of the divergence section. 15 This is a
period when field experiments overlapped with drafting and rewrit-
ing - during which the ideas of the compressed phase were consoli-
dated and tested. In June 1855, as we have noted, Darwin measured
plant species diversity in a Down field. What followed, beginning
that season, but intensifying in 1856 and continuing through May
1858, was that Darwin performed a variety of rough - 'square-yard of
turf experiments using 1' x 3' and 3' x 4' experimental patches in
the lawn, orchard, and meadows of Down House to study diversity,
dominance, struggle, and survival. It was in parallel with this effort
that Darwin made the move that clinched his position.
We find that the tight link between divergence and selection is
forged first in a note written at the end of the 1855 growing season,
after Darwin's first year of field experiments, and then in a note
written at the end of the 1856 season. We can look at these seriatim:
Aug 19 Issl owing to power of propagation not only as many individuals
crowded together, but "forms" for more can be supported on same area,
when diverse, than when of same species. ... As where many individuals
crowded together some will die, so will forms. . . . All classification follows
from more distinct forms being supported on same area. (Kohn 2006, DAR
205.5:157)
Sept 23d /1856/ The advantage in each group becoming as different as pos-
sible, may be compared to the fact that by division of <land> labour most
people can be supported in each country - Not only do the individuals of
each group strive one against the other, but each group itself with all its
members, some more numerous, some less, are struggling against all other
groups, as indeed follows from each individual struggling - (Kohn 2006, DAR
205.5: 171)
These passages have a lot in common. Divergence and struggle are
linked in both, and we can take the division of labor as a given in
August 1855. The main difference is that in September 1856 we see
15 The outline of the theory that Darwin sent Asa Gray in September 1857, a few
months after writing the first version of the divergence section, shows that all the
essential ideas were in place and explicitly grouped as a 'principle of divergence'.
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Darwin's Keystone 107
nested intraspecific and interspecific struggles, the signature struc-
ture of divergence in the Origin. So if there was one point where the
adaptive argument of the principle of divergence clicked, this was it,
just as Ospovat said nearly thirty years ago (1981). Here at last was
sufficient amplification of natural selection to overcome crossing
and to account for the origin of species. Here is where the principle
of divergence per se - 'more life can be supported' -is transformed
into the compounded inter- and intraspecific selection-driven argu-
ment for divergence that produces ecological division of labor.
Darwin had already begun writing Natural Selection in May 1856
and had progressed steadily through many chapters. By the time he
came to the chapter on natural selection, it was March 1857 - fully
ten months after he wrote the definitive 1 3 September 1856 note. But
the ideas were firmly in place, and the development of the principle
of divergence was complete. When it came time to write the natural
selection chapter, and to set the keystone into the arch, Darwin was
ready. But the botanical arithmetic calculations were not. Now we
enter a third and final phase, between April 1858, when he supple-
mented the original divergence section with the famous branching
diagram, and September 1858, when he produced Chapter 4 of the
Origin, refining the explanation of the diagram to clearly stipulate
the separation of lines of descent by extinction of less improved
parental, sibling, and intermediate forms. Despite these revisions,
the logic of the principle of divergence remained unaltered.
In devising the principle of divergence, Darwin resolved much
that had long remained unsatisfactory and incomplete in the edifice
of his species theory. In the end he accomplished, to his own satis-
faction, a unified explanation of the origin of adapted species and a
unified account of the historical generation of living creatures. Per-
haps what impresses one most about Darwin's intellectual process in
this endeavor is first the hard work and then the intellectual flexibil-
ity required to formulate and support just this one part of the Origin.
From the minute anatomical study of barnacles, to the tedious calcu-
lation of taxonomic proportions in flora upon flora, to the counting
of grasses in Great Pucklands, the great theorist resolutely pursued
the evidence he needed to make his case. At the same time one
marvels at the hard thought and change of perspective required to
resuscitate the broken 1844 theory. With what effort of will did he
take up this essay, which had diminished natural selection to near
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108 DAVID KOHN
insignificance? And with what imagination did he replace it with a
reasoned yet inspiring explanation of nature's abundance that made
selection the most potent of all biological causes? And yet we have
seen how this thinking scientist was both nourished and diminished
by the general ideas and prejudices of his time and place. Like one of
Darwin's entangled square yards of turf, studying Darwin's princi-
ple of divergence, close up, is like peering into a microcosm teeming
with intellectual life.
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7 Darwin's Difficulties
Chapters 6 and 7, on "Difficulties on Theory" and "Instinct," are
the fulcrum of Darwin's Origin of Species. They come at the center
of the work, after the first five chapters that explicate the theory of
natural selection and outline the causes and effects of the mysterious
laws of variation on which Darwin's argument for natural selection
depends. These two chapters sustain the narrative drive that Darwin
had been building through the first five chapters and introduce new
scientific and emotional dimensions, particularly in his treatment
of the theory's larger implications for the religious context in which
he was writing.
"Difficulties on Theory" and "Instinct" take on two classes of
what Darwin describes as "a crowd of difficulties [that] will have
occurred to the reader . . . [l]ong before having arrived at this part of
my work" (Origin, 171). The first class of problems, covered largely
in Chapter Six, deals with the apparent lack of transitional forms,
wide variation within taxa, organs of apparently small importance,
and, most importantly, the difficulty of giving a wholly materialist
explanation for the evolution of structures and organs of extreme
perfection, such as the vertebrate eye. The second class, covered
in Chapter Seven, deals with the evolution of behavior and instinct,
phenomena for which the physical basis was quite unknown (as with
the laws of variation), and which thus presented particular problems
for a materialist explanation.
Moreover, these required two concurrent, qualitatively different
categories of explanation. The first was technical: how could organs
of extreme perfection, like the eye, or instincts of extreme perfection,
like building honeycombs, have been evolved through the blunder-
ing, chancy process of natural selection? Even more challenging, how
109
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110 A. J. LUSTIG
could structures and instincts that were inexplicable even on other
materialist evolutionary theories - most importantly, the differen-
tiated sterile castes of the social insects - have evolved to a high
degree of perfection?
Darwin's second category of explanation was theological, respond-
ing to the arguments of the natural theologians who had formed his
own early thinking about natural history and whose arguments, still
in 1859 the most compelling for explaining the order and beauty of
the natural world, were deeply familiar to his audience as well. The
natural theologians' argument for the existence of God rested on the
argument from design, the proposition that (as its most celebrated
proponent, William Paley, put it in 1802), just as the existence of
the human watchmaker can - and must - be inferred upon the dis-
covery of a watch, even if found on a barren heath in the absence of
any prior knowledge of the device or its purpose, so too can - and
must - the existence of the Divine Creator be inferred from observa-
tion of and reasoning about the manifest order and beauty of nature.
The argument from design, however, entailed difficulties of its own-
in particular, its implications for theodicy, the problem of explaining
how evils (like famine and death, or the appalling instincts that lead
ichneumon wasps to parasitize living but paralyzed caterpillars, or
cuckoos to take ruthless advantage of the parental instincts of other
hapless birds, or ants to make "slaves" of other ants) can exist in the
natural world at all if God the Designer is both infinitely powerful
and infinitely benevolent. In the course of substituting materialist
explanations for the evolution of perfect organs and instincts, and for
the evolution of apparently "odious" instincts, Darwin both implic-
itly and explicitly substituted new ways - they might be described
as natural ^theological ways - of understanding these problems as
well.
In the case of organs and instincts of great perfection, Darwin
took on the two classes of explanation simultaneously. He chose
as the centerpieces of his explanation two of the classic examples
from the natural theological literature of the manifestation of divine
ordering of the living world: Paley's great example of the structure of
the vertebrate eye, and the construction of mathematically optimal
honeycombs by little insects of little (though crucially not, Darwin
would argue, of no) intelligence, a golden oldie of natural theology.
The two instances were explicitly linked for him; in marginal notes
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Darwin's Difficulties 1 1 1
to a discussion of honeybee instincts in a work on natural theol-
ogy that he read in 1840, Darwin noted, "Very wonderful - it is as
wonderful in the mind as certain adaptations in the body - the eye
for instance, if my theory explains one it may explain other" (di
Gregorio, 92).
In both cases, Darwin paid tribute in the Origin both to the per-
fection of the character under discussion and to the immense dif-
ficulty in explaining it otherwise than by divine fiat. "He must be
a dull man," Darwin agreed with the reader, "who can examine
the exquisite structure of a comb, so beautifully adapted to its end,
without enthusiastic admiration. . . . Grant whatever instincts you
please, and it seems at first quite inconceivable how [hive-bees] can
make all the necessary angles and planes, or even perceive when
they are correctly made" [Origin, 224). Likewise, to "suppose that
the eye, with all its inimitable contrivances for adjusting the focus
to different distances, for admitting different amounts of light, and
for the correction of spherical and chromatic aberration, could have
been formed by natural selection, seems, I freely confess, absurd in
the highest possible degree" [Origin, 186).
Nevertheless, conclusions about inimitability or beautiful adap-
tation, just like sensations of enthusiastic admiration or absurdity,
must all give way. The logical observer's "reason ought to conquer
his imagination" [Origin, 188), difficult as Darwin admitted this
subjugation to be on the basis of his own experience. If he has been
able to accept the argument for natural selection and its power up
until the point of confronting the problem of perfection, perfection
itself should pose no greater difficulty. An entirely material expla-
nation will suffice here as elsewhere. In the cases of both structure
and instinct, the solution is the same. We may not be able to see
the intermediate stages in the evolution of the human eye or the
hive-bee's comb-building instinct, but we can look laterally, to sim-
pler related forms, to build up a series of plausible intermediates
that exist in the here and now. We have no fossil data on the evo-
lution of eyes among vertebrates, and they are so highly developed
among all living vertebrates that no contemporaneous series can be
constructed, but among extant invertebrates a whole range of eyes
still exists, from "an optic nerve merely coated with pigment, and
without any other mechanism . . . until we reach a moderately high
state of perfection" [Origin, 187). The existence of this sequence of
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112 A. J. LUSTIG
"graduated diversity" among living organisms itself makes the exis-
tence of historical gradation the more plausible, particularly "bear-
ing in mind how small the number of living animals is in proportion
to those which have become extinct" [Origin, 188). Moreover, so
long as each eye, from the simplest light-sensitive nerve onward, is
"useful to its possessor," natural selection can be constantly work-
ing on the heritable variations always present to produce greater
perfection in succeeding generations [Origin, 186).
As with the case of invertebrate eyes, the hive-bee's honeycomb,
while mathematically perfected, differs only in degree rather than
in kind from combs constructed by other species of bee, which
range from simple irregular round or cylindrical cells of wax among
humble-bees through the honey cells of Mexican bees of the genus
Melipona, constructed as spheres that normally adjoin with others
at one, two, or three points, each of which then becomes a shared
flat wall of wax, of the same thickness as a normal exterior cell
wall; where three such walls come together, they form a pyramid
like that forming the basis of every hive-bee cell. "Hence we may
safely conclude that if we could slightly modify the instincts already
possessed by the Melipona, and in themselves not very wonderful,
this bee would make a structure as wonderfully perfect as that of the
hive-bee" [Origin, 117). This would require only that hive-bees be
shaped by natural selection to adhere to a few more or less absolute
rules: stand a certain distance from your coworkers; always construct
spheres or cylinders but construct flat walls where these intersect
with the coworkers' cells; don't make the walls too thick or too thin.
And natural selection could act on these simple instincts because
they conferred an immediate profit on the bees at each intermedi-
ate stage, as Darwin's theory required: "bees are often hard pressed
to get sufficient nectar [and] a prodigious quantity of fluid nectar
must be collected and consumed by the bees in a hive for the secre-
tion of the wax necessary for the construction of their combs. . . .
Hence the saving of wax by largely saving honey must be a most
important element of success in any family of bees" [Origin 233-4).
Incremental improvements in the efficiency of honeycomb construc-
tion would yield continual, if incremental, advantages to the bees
who made them, until that "stage of perfection in architecture" was
reached, beyond which "natural selection could not lead; for the
comb of the hive-bee, as far as we can see, is absolutely perfect in
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Darwin's Difficulties 113
economising wax." Thus can natural selection take "advantage of
numerous, successive, slight modifications of simpler instincts" to
derive "the most wonderful of all known instincts," the honeybee's
[Origin, 235). No Designer need be postulated.
In both these cases, of perfect structures and of perfect instincts,
Darwin dodged a bullet he likewise dodged in the work as a whole.
Just as "my theory" could shed no light on the ultimate origins of
life, but only on the processes that led to its progressive differen-
tiation thereafter, so Darwin explicitly disavowed theorizing either
about the origins of the most primitive eyes or about the material
basis and origins of instincts: "How a nerve comes to be sensitive
to light, hardly concerns us more than how life itself first origi-
nated" (although Darwin went on to assert that "several facts" led
him to believe that any sensory nerve could become sensitive to
light) (Origin, 187). In parallel, for instincts, Darwin averred that "I
must premise, that I have nothing to do with the origin of the pri-
mary mental powers, any more than I have with that of life itself"
[Origin, 207). Natural selection could not speak to the material ori-
gins of absolute novelties. Subsequently, however, its power was
absolute, so much so that Darwin staked his whole theory on nat-
ural selection's ability to account even for cases of apparent per-
fection. "If it could be demonstrated," he declared, "that any com-
plex organ existed, which could not possibly have been formed by
numerous, successive, slight modifications, my theory would abso-
lutely break down. But I can find out no such case." In a character-
istic piece of rhetorical judo, Darwin transformed the "inconceiv-
able" and "absurd in the highest degree" with which he had begun
his discussions of the idea that natural selection might shape the
eye or the honeycomb into a categorical "no such case" [Origin,
189).
The difficulty posed by the problem of perfection for Darwin was
more theological than material, since, given the initial conditions (a
light-sensing nerve), natural selection clearly had the materials on
which to work. The case of instincts, however, was different. There
was no convincing theory about how instincts, or indeed any men-
tal or moral powers, were rooted in the material body (and some,
though not all, natural theologians denied that they were material).
Their origins, in history and ontogeny, were mysterious. And finally,
in certain cases, most particularly those of the social insects with
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114 A - J- LUSTIG
sterile worker castes, these difficulties were compounded both by
being combined with often flamboyant modifications of physical
structure and by the inability to explain the continuance of these
structures and instincts by straightfoward inheritance from parents
(who did not manifest either). Darwin accordingly hived his discus-
sion of instinct off from the "difficulties" discussed in Chapter 6,
and dealt with them separately. Characteristically, as in the case of
perfect organs, he structured his argument so that the problem that
even to him had "at first seemed insuperable, and actually fatal to
my whole theory" [Origin, 236) - namely, the evolution of differ-
entiated sterile castes in the social insects - was revealed, in the
capstone to the two chapters, not only to be wholly explicable on
the basis of natural selection, but to be explicable on no other mate-
rial basis. Indeed, it was a most gratifying vindication of his "faith
in this principle . . . that natural selection could have been efficient
in so high a degree" [Origin, 242).
Darwin had further reasons for highlighting the importance of
the evolution of instincts for the theory of natural selection. Not
only did he have to argue that, unknown as the material basis of the
powers of mind might be, the same methods of analysis should be
applied to them as to corporeal structures (an argument by no means
original to Darwin), he also had two further implicit ends in view.
The first was, again, theological; Darwin found that his new mecha-
nism to explain the evolution of instincts provided, if not a solution
to the problem of theodicy, at least an end run around it. The second
was long-range. Darwin deliberately steered clear in the Origin of
questions of human origins and evolution, but these were always
on his mind from the inception of his evolutionary thinking. Cen-
tral to any explanation of human evolution, Darwin believed, would
be explanations of two distinctive human characteristics: sociality,
and the development of the moral sense that qualitatively distin-
guishes humans from other animals. A theory of instincts was vital
to both.
Instinct was a particularly tricky subject because it was much
harder to define than a wing or an eye. To all the enormous initial
difficulties involved in discussing the origin and action of mental
powers in general, had to be added some differentiation of the idea of
instinct from those of habit or of reason, and this was by no means
easy. Some cases, as, for example, skilful first-time cocoon building
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Darwin's Difficulties 115
or nest building by individuals who had never seen one made and
could have no conception of their ultimate purpose, were relatively
clear-cut. However, often matters were not so clear. Were habits
acquired during the life of an organism and practiced enough to
become automatic the same as instincts, or analogous? Indeed, was
the origin (by the inheritance of acquired characters) of instincts
innate in subsequent generations? Could or did elements of ratioci-
nation ever play a role in the execution of an instinct, or was the
power of reasoning limited to the higher animals alone, or indeed
solely to human beings?
Darwin was in a position to tackle these issues in ways that would
not have been possible even fifty years before his time, thanks to a
wealth of new observations, chiefly on the social insects, many of
them explicitly natural theological in character, that had been made
over the previous seventy-five years. The social insects (the ants,
bees, wasps, and for Darwin to a much lesser extent the termites)
occupied both very old and very recent positions in the annals of nat-
ural history. Since antiquity, ants and bees in particular have served
as mirrors and proxies of human beings in literature and natural
history.
Eighteenth- century natural historians turned their new disci-
plines of attention to the social insects (see Daston 2004) and found
much to criticize in ancient accounts: while the sluggard was coun-
selled to go to the ant because she, though "having no guide, overseer,
or ruler, provideth her meat in the summer, and gathereth her food
in the harvest," the attentive observers of northern Europe denied
that she did any such thing. (Only later in the nineteenth century
were observations made by naturalists of Mediterranean ant species
that do indeed harvest seeds, vindicating the wisdom of Solomon,
at least in myrmecology. ) In building his account of the evolution of
instincts, Darwin drew heavily on the work of several of these natu-
ralists (see Drouin 2005 ). He had read the work of the French observer
of ants Pierre-Andre Latreille, whose Histoire naturelle des fourmis
(1802) he had picked up even before leaving on the Beagle, and his
copies of the works of the Swiss father and son Francois and Pierre
Huber, on bees and ants, respectively [Nouvelles observations surles
abeilles [18 14] and Recherches surles moeurs des fourmis indigenes
[18 10]), were both heavily annotated and extensively drawn upon for
the Origin (di Gregorio, 409-13).
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Il6 A. J. LUSTIG
It was in the works of natural theologians, however, that Darwin
found the strongest supports for and challenges to his emerging views
on the evolution of instinct. Naturalists in general, natural theolo-
gians included, were divided on the subjects of both the nature of
instincts and whether or not there was an irreducible gap between
the reasoning powers of human beings and the merely mechanical
manifestations of animal behavior. Paley, for example, came down
on the side of an unbridgeable chasm between human and animal
intelligence. Other naturalists, however, were not so sure. Henry,
Lord Brougham, whose Dissertations on Subjects of Science Con-
nected with Natural Theology (1839, written to accompany an illus-
trated edition of Paley's Natural Theology) Darwin read in 1840,
opined on the basis of his own empirical research that even seem-
ingly simple creatures were capable of a degree of free rational action,
in which "the means are varied, adapted, and adjusted to a varying
object" (quoted in R. }. Richards 1987, 138). For Brougham, writing in
the British tradition of sensationalist epistemology to which Darwin
also belonged, animals were not Cartesian machines without self-
awareness; they had a degree of freedom of action (in Brougham's
view, to be sure, granted to them by the Creator) that meant that
their intelligence differed from ours in degree but not, crucially, in
kind. To insist on an uncrossable gulf between human and animal
mind was not a necessary component of natural theological reason-
ing. Darwin found a second component of Brougham's reasoning to
be compelling, albeit in a way that would not have pleased Brougham
himself. Brougham argued that, given that many instinctual actions
were performed without an animal's having any possible experience
of either their performance or their object (as in the case of soli-
tary wasps that stocked nesting burrows with particular species of
spiders or grubs for larvae they would never see, or a chick peck-
ing out a hole from inside the eggshell to reach a world of which
it had no experience), there could be no question of these instincts,
or by extension any instincts, having evolved by the inheritance of
repeated habit, as Lamarck and other early evolutionists believed.
Darwin concurred with Brougham's challenge, but did not take this
refutation of use inheritance as a disproof of his theory of descent
with modification. On the contrary, while it challenged him to think
more deeply about the limits of habit inheritance (which he contin-
ued to think important), it also caused him to consider how natural
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Darwin's Difficulties 117
selection could produce these one-time marvels in an animal's exis-
tence, unaided by habit inheritance. Brougham's work, he concluded
in his notebooks, was "profound" [Notebooks, 580).
The work that probably had the greatest influence on Darwin's
thinking about instinct until about 1858, and that presented him
with the starkest difficulty for his theory, was William Kirby and
William Spence's Introduction to Entomology. The collaboration
of a High Tory churchman and natural theologian (Kirby, later the
author of the seventh Bridgewater Treatise) and a secular physio-
cratic political economist (Spence), the Introduction was the stan-
dard work on entomology for most of the nineteenth century. Darwin
esteemed the whole highly and particularly the chapter on instinct
("the best discussion on instincts ever published," he wrote in the
long manuscript "Natural Selection," which formed the basis of the
Origin [Species Book, 468]). This discussion was written by Spence,
in contradistinction to the avowed views of his coauthor, who explic-
itly disassociated himself from them in volume 3 of the work (see
Clark 2006). Spence noted the difficulty of defining instinct, but gave
a working definition that Darwin was to adapt for the Origin:
Without pretending to give a logical definition of it, which, while we are
ignorant of the essence of reason, is impossible, we may call the instincts
of animals those unknown faculties implanted in their constitution by the
Creator, by which, independent of instruction, observation, or experience,
and without a knowledge of the end in view, they are impelled to the per-
formance of certain actions tending to the well-being of the individual and
the preservation of the species. (Kirby and Spence, 2: 471)
Spence, a secularist, agreed with Brougham's view of the material
basis of powers of mind; but, more to Darwin's taste than to a
natural theologian's, he limited the Designer's powers of endowing
these to the original creation of species, rather than agreeing with
Brougham's "interposition of the Deity at each moment" in the
operation of instinct (quoted in Clark, 46). Moreover, Kirby and
Spence affirmed the contiguity between the operation of instinct
and reason: age, for example, could bring a measure of wisdom even
to insects, which gain knowledge from experience, which would be
impossible if they were not gifted with some "portion of reason"
(Kirby and Spence, 2: 415).
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1 1 8 A. J. LUSTIG
Kirby and Spence also brought Darwin to a most formidable obsta-
cle to his incipient theory of natural selection, namely, the problem
of the evolution of differentiated neuter castes in the social insects,
where no amount of acquired variation in habit or structure among
sterile individuals could possibly be passed directly to succeeding
generations. Bees, and more particularly ants and termites, may have
one or more worker forms, different in both habits and physical
structure from their fertile parents. Accounting for their evolution
was particularly sticky. The margins of Darwin's copy of Kirby and
Spence were littered with memoranda of his frustration (among oth-
ers - "Neuters do not breed! How instinct acquired," and "I can
understand a neuter having any instinct which the female could
have had, but no others cd have been acquired by habit " (di Gregorio,
452). Robert Richards (1987) has persuasively argued that Darwin's
inability to devise a convincing account of the evolution of neuter
castes, a problem potentially, as he rightly observed, "fatal to my
whole theory," was a principal cause of his delay in publishing the
theory of natural selection. It was only well on in the writing of the
big "Natural Selection" manuscript, in 1858, that he saw his way
through to a solution, shortly before Alfred Russel Wallace's letter
jolted him into the frenzy of abstracting and writing that produced
the Origin.
In redacting his thoughts on the evolution of instinct for the
Origin, Darwin structured his argument in the way that had, by
Chapter 7, become familiar to the reader. Demurring at the outset
to speculate on the ultimate origins of mental powers, he then pro-
vided a loose overview of what he meant by instinct, derived, as
noted, from Spence's definition in the Introduction to Entomology.
Prefacing his remarks with the statement that he would not attempt
any general definition of the term, he observed that "It would be
easy to show that several distinct mental actions are commonly
embraced by this term" [Origin, 207). The phenomenon could be
gotten at only by concrete example:
every one understands what is meant, when it is said that instinct impels
the cuckoo to migrate and to lay her eggs in other birds' nests. An action,
which we ourselves should require experience to enable us to perform, when
performed by an animal . . . without any experience, and when performed by
many individuals in the same way, without their knowing for what purpose
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Darwin's Difficulties 119
it is performed, is usually said to be instinctive. But I could show that none
of these characters of instinct are universal. A little dose ... of judgment
or reason, often comes into play, even in animals very low in the scale of
nature. [Origin, 207-8)
Instinct might also be compared to habit, although while this "com-
parison gives, I think, a remarkably accurate notion of the frame of
mind under which an instinctive action is performed," it gives no
indication "of its origin" [Origin, 208).
Having brought his reader to a point of common ground, if not
perfect agreement, Darwin then turned to his most familiar, princi-
pal, method of argument, by analogy from artificial selection. The
instincts of domestic animals vary, both from one individual to
the next and from one generation to the next, particularly under the
action of deliberate selection, as for example tumbling in pigeons or
pointing in hunting dogs; they can also be bred out of a line, whether
deliberately, as in the case of English dogs (in contrast to Fuegian
animals) selected over generations not to attack livestock, or inad-
vertently, as in the loss of brooding instincts in some varieties of
domestic poultry. The inheritance of acquired habit seemed to oper-
ate, at least in part, in some cases (as in pointing), while it seemed
most unlikely in others (tumbling). As under domestication, so in
nature, in cuckoos, aphids, honeybees, ants.
Darwin paid particular attention to the instincts of ants, because
these were among the most extraordinary known. The sensational
case of so-called ant "slavery" had been discovered at the turn of the
nineteenth century by Pierre Huber, whom Darwin esteemed as "a
better observer even than his celebrated father" [Origin, 219). Huber
discovered that workers of certain ant species, Formica sanguined
and Formica (later Polyerges) rufescens, regularly raided nests of a
related ant species, Formica fusca, and carried large numbers of lar-
vae and pupae back to their own nests. These then hatched out in
the alien nests and immediately set to work as though in a colony
of their own, exhibiting their normal instincts for nest construc-
tion, brood tending, mutual feeding, and so on, though subverted
to the advantage of the "slave-making" species. While colonies of
F. sanguinea did not seem to be absolutely dependent on their cap-
tives, occasionally being found without any, F. rufescens was abso-
lutely dependent on a regular infusion of fusca individuals, rufescens
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120 A. J. LUSTIG
workers being entirely incapable of making their own nests, feeding
themselves, or tending their own larvae. Without F. fusca, Darwin
noted, "the species would certainly become extinct in a single
year" [Origin, 219). Darwin, a keen and exact observer himself,
devoted many hours over three successive summers to confirming
and extending Huber's observations on Formica sanguined, which
also occurred in the south of England, along with its prey species,
F. fusca.
The extraordinary specificity and strangeness of the slave-making
instincts would have been enough, presumably, to account for
Darwin's interest, but he avowed another reason in his opening dis-
cussion of them in the Origin, one not directly derived from the sci-
entific interest of the behavior, but rather from its repugnant moral
implications. "Although fully trusting to the statements of Huber,"
Darwin carried out his own observations, he claimed, because he felt
the need "to approach the subject in a sceptical frame of mind, as
any one may well be excused for doubting the truth of so extraordi-
nary and odious an instinct as that of making slaves" [Origin, 220).
Raised in a famously abolitionist family, familiar with the horrors
of human slavery firsthand from his South American experiences
aboard the HMS Beagle, Darwin was loath to believe that the insti-
tution of slavery could be in any way inscribed in nature (as some
defenders of human slavery indeed claimed). The identification of
ant "slavery" with human slavery, however, was evidently overde-
termined for nineteenth- century observers, whether abolitionists or
slavery advocates. Few naturalists, for example, argued that as the
ants in question were of two different species, rather than members
of the same kind, the analogy did not hold, or might be more closely
made to domestication than to slavery - though the unfortunate
coincidence that both of Huber's warlike "slave-making" species
were large and red, while the "slave" species was small and black,
probably inevitably sealed the metaphor (see Clark 1997a). Even the
abolitionist Darwin succumbed to its allure; he triumphantly wrote
Joseph Hooker of his first observations of the phenomenon in May
1858: "I had such a piece of luck at Moor Park: I found the rare Slave-
making Ant, &. saw the little black niggers in their Master's nests"
[Correspondence, 7: 89).
The existence of a spectrum of instincts between the still rel-
atively independent F. sanguinea and the helpless F. rufescens
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Darwin's Difficulties 121
allowed Darwin to frame a conjecture as to the evolutionary ori-
gins of slave making: ants in general, he observed, would carry off
the pupae of other species back to their nests to store with other
food. If some of these chanced to hatch out, the ants "thus unin-
tentionally reared" would naturally "follow their proper instincts,
and do what work they could. If their presence proved useful to the
species which had seized them - if it were more advantageous to
this species to capture workers than to procreate them - the habit
of collecting pupae originally for food might by natural selection be
strengthened and rendered permanent for the very different purpose
of raising slaves" (Origin, 223-4). Straightforward carnivory might
thus become immoral theft of both bodies and labor.
The "odious" instincts of slave-making ants troubled Darwin; so
too did other instances where animals behaved in ways viscerally
repugnant to developed morality and religion. Natural theologians
had been exceedingly troubled by such instances as cuckoo chicks
that deliberately ejected their foster siblings from their nests, to cer-
tain death, in order to usurp all the unwitting parents' resources
to themselves; or ichneumon wasps that paralyzed living caterpil-
lars and laid their eggs in their bodies, to hatch out into larvae that
would slowly eat the caterpillar from the inside out, gruesomely
preserving their hosts' nervous systems and vital organs to the very
living last, so as not to destroy their own food supply - the cater-
pillar presumably suffering all the while in a horrific reenactment
of the Passion in miniature. How a benevolent, omnipotent God
could not only have allowed but ordained such suffering was a cen-
tral problem of natural theology, an instance of the classic religious
problem of theodicy, the justification of God's goodness in the face
of such apparent evils. Darwin's theory could not make the problem
of natural evils vanish, but he himself found comfort in the idea of
seeing them as unfortunate manifestations of general laws leading
to general happiness, rather than as specific instances of creation
requiring particular explanation. In the conclusion to Chapter 3,
on the struggle for existence, Darwin had consoled himself and the
reader "with the full belief, that the war of nature is not incessant,
that no fear is felt, that death is generally prompt, and that the vigor-
ous, the healthy, and the happy survive and multiply" [Origin, 79).
"Odious" instincts were perhaps an even bitterer pill to swallow, as
they represented instances of deliberate, perhaps even to some degree
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122 A. J. LUSTIG
reasoning, behavior on the part of individual organisms. In this bleak
case, Darwin did not go so far as to offer his readers "consolation."
Nevertheless, the theory of natural selection offered a path out of
the blind alley of theodicy on this question too. "It may not be a
logical deduction/' Darwin wrote in the concluding words of Chap-
ter 7, "but to my imagination it is far more satisfactory to look at
such instincts . . . not as specially endowed or created instincts, but
as small consequences of one general law, leading to the advance-
ment of all organic beings, namely, multiply, vary, let the strongest
live and the weakest die" [Origin, 244). Immoral horrors were the
inevitable consequence of an amoral natural law that would never-
theless, paradoxically, lead to advancement and greater total happi-
ness (and ultimately, Darwin would argue in The Descent of Man,
to the appearance of the moral instincts themselves).
The last, virtuoso case study of the chapter on instinct com-
bined all the elements, scientific and philosophical, that Darwin had
brought into play in the Origin thus far. In his conclusions on the ori-
gins of the slave-making instincts, Darwin had already alluded to the
solution he had at long last found to the problem of explaining ants'
neuter castes. As already observed, this knotty problem had long
retarded Darwin's final shaping of the theory of natural selection.
No dependence on the eventual inheritance of long-repeated habit
could explain neuters' instincts, nor could use inheritance explain
their sometimes greatly modified structures. Special creation truly
did seem to be the only explanation, as Brougham had triumphantly
deduced. How to see a way through it on the basis of natural selec-
tion? Robert Richards (1987) has retraced Darwin's arduous journey
to a solution that he found not only satisfactory, but so clear-cut an
instance of the power of natural selection to elucidate what other-
wise could only be credited to the Designer that Darwin made it the
capstone of these two chapters, a triumphant reverse transubstanti-
ation of the theological to the material realm of explanation.
Characteristically, the path led through artificial selection. Dar-
win reread William Youatt's Cattle: Their Breeds, Management, and
Diseases (1834) in 1857 while writing the manuscript on "Natural
Selection." Youatt described the methods cattle breeders employed
to improve beef cattle. It was not possible to judge, naturally, the
culinary quality of a beef animal without killing it. How then to
improve the breed? "The breeder goes with confidence to the same
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Darwin's Difficulties 123
family" [Origin, 238) and breeds from the tasty animal's relatives,
on the warranted presumption that these animals will also exhibit
the desired characteristics to a greater degree than the norm. Like-
wise, "a well-flavoured vegetable is cooked, and the individual is
destroyed; but the horticulturist sows seeds of the same stock, and
confidently expects to get nearly the same variety" [Origin, 237-8).
Sterility in an individual, whether accidental or innate, is no bar
to its characters being passed on through collateral lines: "selection
may be applied to the family, as well as to the individual" [Ori-
gin, 237). This being the case, even the evolution of regular sterility
among a caste of individuals in a family itself is not terribly difficult
to explain, "not much greater than that of any other striking mod-
ification of structure," given that innate sterility is an occasional
variant met with regularly in insects that would provide the initial
material for selection to work on [Origin 236).
Thus far, however, the explanation covers only the inheritance of
characters possessed by nonreproducing individuals and their fertile
relations alike. How could modifications of instinct and structure
become fixed only in sterile individuals? In fact, Darwin argues, the
same principle applies, odd though this may seem. There are many
cases, he observes, of characters exhibited in only one sex, or only at
particular life stages. In cattle, there are even chance cases of char-
acters, such as longer horns, exhibited only by artificially castrated
males, so that it would presumably be possible, if any one were inter-
ested, to breed a race of long-horned oxen from their short-horned,
but fertile, relations. This difficulty too, "though appearing insuper-
able," is thus "lessened, or, as I believe, disappears" [Origin, 237).
Darwin in the argument on neuter castes recapitulated in minia-
ture the strategy of the Origin's two chapters on "difficulties on
theory," that is, to take the difficulties one at a time (organs of per-
fection, organs of small importance, peculiar instincts) and to reveal,
one by one, that they not only present no difficulty, but in fact (when
properly analyzed and understood) furnish superior illustrations of
the power and reach of natural selection. He thus in the case of
sterile ants built up one difficulty (the evolution of sterility), only
to knock it down in pursuit of another greater one (the differenti-
ation of sterile from fertile castes), only to knock this one down
so he could pull the greatest trick of all out of his hat, the purest
example of the power of "my theory" alone to explain the shape
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124 A - J- LUSTIG
of the living world: explaining how the neuter castes can, as in the
cases of many ants, diverge not only from the fertile castes but also
from each other within a single species, "sometimes to an almost
incredible degree," into workers and soldiers, or foragers and honey-
pots, or any of the many other "such wonderful and well-established
facts" that entomologists had discovered incarnated in ants over the
previous century [Origin, 238-9).
The ontogeny of the argument recapitulates, moreover, the phy-
logeny of Darwin's thinking on the problem. Darwin was able to
solve the problem of multiple castes only by combining his thinking
about selection acting on the family or community with observa-
tions of ant species with multiple castes. He corresponded, begin-
ning in late 1857, with the entomologist Frederick Smith of the
British Museum, a specialist on the Hymenoptera (the ants, bees, and
wasps), on subjects including the morphology of ant castes. Smith
told Darwin, who confirmed with his own observations, that con-
siderable variation occurred in neuter insects within a single nest,
even in species that did not have differentiated castes (this, of course,
accorded gratifyingly with Darwin's ideas on variation in general),
and that, in cases of species with strongly differentiated castes, inter-
mediates between them could nevertheless regularly be found, and
thus "that the extreme forms can sometimes be perfectly linked
together by individuals taken out of the same nest" [Origin, 239).
Darwin's inference from these observations was that, in cases where
wide variation in neuters occurred and where the variations occur-
ring at either end of this spectrum, both proved profitable to the
community:
natural selection, by acting on the fertile parents, could form a species which
should regularly produce neuters, either all of large size with one form of
jaw, or all of small size with jaws having a widely different structure; or
lastly, and this is our climax of difficulty, one set of workers of one size
and structure; - a graduated series having been first formed, . . . and then the
extreme forms, from being the most useful to the community, having been
produced in greater and greater numbers through the natural selection of the
parents which generated them,- until none with an intermediate structure
were produced. [Origin, 241)
Only from this evolved sterility, in fact, could the ants, according to
Darwin, have achieved their exemplary high degree of the division of
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Darwin's Difficulties 125
labor and its attendant efficiencies, since, if all members were fertile,
intercrossing would have caused this fine degree of specialization to
be swamped out.
Thus has natural selection achieved what, through the combina-
tion of perfect structures and perfect instincts, should have appeared
to be the very finest example of the argument from design, "the most
serious special difficulty, which my theory has encountered" [Ori-
gin, 242). Moreover, no other materialist evolutionary mechanism
could do so, either. Darwin indulged himself in a bit of understand-
able self-congratulation to close his discussion of the subject, crow-
ing, "I am surprised that no one has advanced this demonstrative
case of neuter insects, against the well-known doctrine of Lamarck"
[Origin, 242).
Chapters 6 and 7 of the Origin, ostensibly dedicated to confronting
the severe "difficulties on theory" that Darwin worried would bring
down the theory of natural selection (and that he had himself indeed
worried mightily over in the twenty years preceding its writing)
actually serve as its triumphant vindication. The basis of the argu-
ment and its underpinnings having been laid out in the previous five
chapters, these two chapters reveal how each of the difficulties that
Darwin had confronted evanesced, or indeed - in important cases
like the evolution of perfect structures, the evolution of instincts,
and, in culmination, the evolution of differentiated sterile castes in
social insects - was transformed into confirming evidence for his
theory.
Beyond this important work, the chapter on instinct, however,
laid the groundwork for the most important further extension of
Darwin's ideas. From the beginning of his thinking on descent with
modification, he had had two aims in view: to explain the history
of life on Earth, and to explain the origins and nature of human
beings. Vital to the latter project, he early saw, would be an account
of the origins of sociality and of the moral instincts in man; "society
could not go on except for the moral sense, any more than a hive
of Bees without their instincts," he wrote in a notebook of 1838
[Notebooks, 609). Insects served all along for Darwin as important
illustrations of both the range of possibilities in intelligence and the
moral sense, and of the possibilities of illustrating these (as in the
case of the evolution of the eye) in an unbroken contemporaneous
series impossible for vertebrates: "[T]he mental powers of man and
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126 A. J. LUSTIG
the lower animals do not differ in kind, although immensely in
degree/' he concluded in The Descent of Man.
A difference in degree, however great, does not justify us in placing man
in a distinct kingdom, as will perhaps be best illustrated by comparing the
mental powers of two insects, namely, a coccus or scale-insect and an ant,
which undoubtedly belong to the same class. The difference is here greater,
though of a somewhat different kind, than that between man and the highest
mammal .... No doubt this interval is bridged over by the intermediate
mental powers of many other insects,- and this is not the case with man
and the higher apes. But we have every reason to believe that breaks in the
series are simply the result of many forms having become extinct. {Descent,
i: 186-7)
Darwin's account of the evolution of sociality in human beings was
likewise analogous to the account of the evolution of insect societies
he gave in Chapter 7 of the Origin, although he continued to rely in
his thinking about the former on the eventual inheritance of long-
repeated habit (in strengthening both inheritance and the faculty of
sympathy), the mechanism he had been forced to abandon in the
case of neuter insects. The social instincts, developed by selection
through their profit to the community, operate in part by the faculty
of sympathy that knits its members together. Groups, whether of
insects or men, that were more cohesive through these means would
ultimately displace or conquer other, less social associations, and
the evolution of sociality and morality would thus become a motor
leading to ever-greater perfection of societies. To be sure, the shape
these would take would depend on the species' peculiarities and
past history - dogs' consciences would not be the same as men's,
Darwin reflected to himself already in 1838 [Notebooks, 564), and
if, he concluded decades later in the Descent, "to take an extreme
case, men were reared under precisely the same conditions as hive-
bees, there can hardly be a doubt that our unmarried females would,
like the worker-bees, think it a sacred duty to kill their brothers,
and mothers would strive to kill their fertile daughters; and no one
would think of interfering." These horrors as our own species would
understand them would nonetheless arise from "some feeling of
right and wrong, or a conscience" in bee-men with "intellectual
faculties ... as active and as highly developed as in man" [Descent,
73).
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Darwin's Difficulties 127
Darwin was gratified to see his ideas on instinct taken up by other
investigators during his lifetime. Darwin's protege and intellectual
son, George Romanes, took up the origin of mind and instinct, and
struggled lifelong, like his mentor, with questions of natural the-
ology and theodicy (see Richards 1987). Darwin's neighbor and fre-
quent information source John Lubbock supported and furthered
Darwin's ideas on both the social insects and the evolution of man
(see Clark 1 997b). A younger generation of myrmecologists (ant biol-
ogists) sought to apply Darwin's insights to new studies of ant mor-
phology, behavior, and societies. Darwin engaged in an enjoyable
correspondence beginning in 1874 with the young Swiss entomolo-
gist Auguste Forel, who had sent him a copy of his Fourmis de la
Suisse-, Darwin wrote, gratified, in the margin of his copy, "approves
of what I have said of origin of slave-making" (di Gregorio, 239).
Even the German Jesuit myrmecologist Father Erich Wasmann was
a convinced evolutionist who developed theories of the evolution
of various sorts of cooperation within ant nests (see Lustig 2004;
Sleigh 2006). The tradition of using the ants as principal proxies
for the study of the evolution of sociality as a general phenomenon
has endured through the twentieth century, through E. O. Wilson's
The Insect Societies (1971) and Sociobiology (1975), and on into the
twenty-first.
Modern framings of Darwin's questions about the origins of
sociality, however, have undergone a fundamental transformation
that has greatly obscured their original context. William D. Hamil-
ton, in his 1964 formulation of the idea of inclusive fitness or kin
selection, argued that the evolution of altruism among members of a
community (he took the hymenopteran social insects as a principal
case study) resulted from the advantage accrued to each individ-
ual through the preservation of her genes through collateral lines of
descent, furthered by her own self-sacrifice on their behalf. In doing
so, Hamilton made a profound shift in the object of interest to the
evolutionary biologist and in the language and concepts for under-
standing it. Where Darwin had asked how sterility would profit the
community and found "no great difficulty" in answering that ques-
tion (taking the evolution of the cooperative, moral instincts to be
an inevitable concomitant to the evolution of sociality), Hamilton
demanded to know how sterility could possibly profit a sterile indi-
vidual and found great difficulty indeed in answering the question,
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128 A. J. LUSTIG
struggling long and hard with it over a period of years, much as
Darwin had done for the evolution of differentiated castes - a ques-
tion that was, ironically, for Hamilton, armed with modern genetics,
a question of no great difficulty once the barrier of sterility was over-
come. The transformative program of selfish gene's-eye analysis that
Hamilton and other biologists inaugurated in the 1960s and 1970s
has been enormously successful, and though they have so altered
the language and thinking that Darwin would perhaps scarcely rec-
ognize them, its proponents have never ceased to look back to their
illustrious progenitor.
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SANDRA HERBERT AND DAVID NORMAN
8 Darwin's Geology and
Perspective on the Fossil Record
CHARLES DARWIN AS GEOLOGIST
In November 1859, Darwin's masterpiece, the Origin of Species,
was published. Earlier that year, in February, he had been awarded
the Wollaston Medal, the highest honour of the Geological Society
of London, "for his numerous contributions to Geological Science,
more especially his observations on the Geology of South America,
on the Phaenomena of Volcanic Islands, on the structure and distri-
bution of Coral-reefs, and his Monographs on recent and fossil Cir-
ripedia" [Correspondence 7: 237; Darwin 1842, 1844, 1846, 1851a,
1851b, 1854a, 1854b). Also contributing to Darwin's high reputation
as a geologist was his Fossil Mammalia, a publication from the voy-
age of HMS Beagle (Darwin, ed. 1840). This work was done jointly
with the anatomist Richard Owen (1 804-1 892). Given Darwin's
prodigious efforts as a geologist, it was natural for the subject to
play an important role in the Origin.
Darwin learned his geology in stages. As a teenage boy, he was
exposed to 'experimentation' as an enthusiastic 'assistant' to elder
brother Erasmus (1 804-1 881) through chemistry and mineralogy in
the garden tool shed at home. From 1825 to 1827, as a medical stu-
dent at the University of Edinburgh, he attended lectures given by
the geologist Robert Jameson (1774-18 5 4) and the chemist Thomas
Charles Hope (1 794-1 871) (Secord 1991). He also gained knowledge
of the invertebrate animals and worked with the Lamarkian zoolo-
gist Robert Edmond Grant (179 3-1 874).
Such clearly innate enthusiasms, having at this time no nat-
ural channel into a future career, were partially diverted by his
129
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130 SANDRA HERBERT AND DAVID NORMAN
abandoning the Edinburgh medical course, to which he seemed
temperamentally unsuited, and transferring to Christ's College,
Cambridge. He took up residence at Christ's in January 1828 and
began reading for an ordinary degree. At Christ's College he joined
his cousin William Darwin Fox (1805-1880), who fostered Darwin's
interest in many aspects of natural history, notably the collection
of beetles. While at Cambridge, Darwin attended the botanical lec-
tures of John Stevens Hens low (179 6-1 861), who introduced him to
such leading figures in natural science at the university as the geol-
ogist Adam Sedgwick (1785-1873) and the philosopher of science
and polymath William Whewell (1794-1866). Having completed and
passed the examinations for his degree by January 1 83 1, Darwin was
obliged to remain in Cambridge in order to complete ten terms of
residence before being allowed to graduate in April 1 83 1 (Peile 1 9 1 3 ).
This was a period of intense reading for Darwin - Alexander von
Humboldt (1769-185 9) and John Herschel (1 792-1 871) being authors
of special importance. Reading Humboldt gave Darwin a sense of
the value of highly organised, scientifically based exploration to for-
eign countries. Through Humboldt he was also introduced to the
progress of science on the continent (Richards 2002). From Herschel
he gained a useful methodology by which observational information
and practical fieldwork could be used to formulate and solve larger
questions in the natural sciences, with specific reference to geology
and its scientific potential. Herschel's influence is apparent in the
Origin, both in the form of its argument and in its sensitivity to geo-
logical questions (Waters 2003b; Herbert 2005). It was during this
period, in 1831, that Henslow directed Darwin to the study of geol-
ogy and arranged for him to accompany Sedgwick in North Wales.
This training proved to be ideal preparation, not for an excursion to
the Canary Islands, which Darwin had originally envisioned, but for
his five-year voyage on HMS Beagle. This opportunity came about
once again through the intervention of Henslow.
In a rapid phase of preparation for his voyage on the Beagle,
Darwin acquired the equipment necessary for his role as an
exploratory naturalist aboard the ship, and a reference library, the
geological component of which was assembled on the advice of
Henslow and Sedgwick. Of these books the most influential by far
was the Principles of Geology by Charles Lyell ( 1797-187 5). The
cumulative effect of Lyell's vision of the interpretative power of
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Darwin's Geology 131
geology as a science that encompassed both the physical and biologi-
cal worlds and their interwoven effects in moulding the surface of the
planet was synthetic and beguilingly powerful. Lyell was grappling
with a number of apparently either 'static' or 'dynamic' phenomena
associated with the then-known crust of the Earth. Static phenom-
ena included: the overall inorganic complexity (extraordinary miner-
alogical and penological diversity), the apparent ubiquity of subdivi-
sions in the geological succession globally the successional appear-
ance of unique fossil types in strata, and the geometrical complexity
of particular geological formations and their occasional intercon-
nectedness (as in ribbon-like mountain ranges). Dynamic phenom-
ena included: the evidence of apparently dramatic sea-level change,
earthquakes and volcanic eruptions, the form and distribution of
oceanic islands, the remarkable geographic distribution of organ-
isms, the influence of climate, and ultimately, of course, the larger
implications derived from observations on the variability of species.
Rationalising, and perhaps integrating, several or perhaps all of these
phenomena (generalised Herschelian and Lyellian goals) had the
potential to lead to a more generally applicable theory of the Earth.
During the voyage Darwin made the most of his training, his read-
ing, and his opportunities for fieldwork. He applied the essentially
inductive programme espoused by his masters to generate synthetic
explanations for many of the pressing and problematic issues then
current in geology. Observations of weathering, gravitational sepa-
ration and differential crystallisation in lava flows, and the effect
of heat on rocks provided keys to understanding the generation
of diversity in the mineral and petrological kingdoms; continental-
scale measurement of raised beaches - linked to his witnessing of
an earthquake and its associated effects - allowed him to provide a
unified explanation for sea-level change, earthquakes, vulcanism,
and continental elevation. This latter set of observations, in turn,
allowed Darwin to develop a theory that beautifully integrated biol-
ogy (the life history of coral organisms) with geology (volcano for-
mation and ocean floor subsidence equilibrated by the elevations of
the land seen on adjacent continents). Darwin's theory of coral reef
formation posited an explanation for the history of the development
of oceanic islands from volcanic island to coral atoll. With elevation
(uplift) and subsidence (fall) as the primary agencies in his under-
standing of the motion of the earth's crust, Darwin wrote in his Red
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132 SANDRA HERBERT AND DAVID NORMAN
Notebook toward the close of the voyage, "Geology of whole world
will turn out simple" [Notebooks, 44 [RN, 72]).
On his return from the Beagle voyage, Darwin presented the
results of his geological researches at the Geological Society of
London. The agencies of elevation and subsidence provided a unity -
and a style - to much of his work (Rhodes 1991). For example, in 1838
he wrote of "the grandeur of the one motive power, which, causing
the elevation of the [South American] continent, had produced, as
secondary effects, mountain-chains and volcanos" (Darwin 1840).
The term "grandeur" is already redolent of what would appear in
the closing passage of the Origin many years later.
During the early 1840s, Darwin was surprised and disconcerted
on one score: the advent and rapid success of 'glacial theory' as pro-
moted by Louis Agassiz (1 807-1 873) (Rudwick 1974; Herbert 2005).
Darwin incorporated many of these 'new' views, and glacial theory
appears prominently in the Origin. With regard to Darwin's adop-
tion of transmutationism in March 1837, the palaeontological com-
ponent was critical. It is to that subject we turn next.
darwin's palaeontology
While the assiduous compilation of specimens and detailed geologi-
cal observation and measurement formed the core of Darwin's work
each time he disembarked from the Beagle, an important, intellec-
tually stimulating, component of his collection was represented by
fossils, with which he was far less well acquainted. The first notice
taken of fossils was his discovery of large fossil mammal bones in
Patagonia toward the end of his first year aboard the Beagle. He wrote
in his notes, "[T]he number of fragments of bones of quadrupeds is
exceedingly great: - I think I could clearly trace 5 or 6 sorts" (DAR
32.1.64). Large vertebrate fossils from South America were known
through the discovery of Mastodon (an elephant-like proboscidean)
and Megatherium (a giant ground sloth) remains. Darwin was able
to collect remains that were recognisably mastodont and megath-
eroid, but additional material indicated a greater diversity of life than
had previously been reported. Greater resolution awaited specialist
research upon Darwin's return to Britain. He was, however, aware of
the general anatomical similarity between some of these fossils and
the uniquely South American animals ('edentates' and its diversity
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Darwin's Geology 133
of ungulates: notoungulates, litopterns, etc). For example, Darwin
had collected patches of tessellated bony armour that, though con-
siderably larger in size, resembled the bony plates that covered the
bodies of living armadillos. Richard Owen, the renowned British
comparative anatomist, willingly aided Darwin in the description
and assignment of these fossils. In the major report on the fossil
mammals (Owen 1 840), he confirmed Darwin's suspicions by reveal-
ing the presence of various 'edentate' ground sloths [Megatherium,
Megalonyx, Mylodon, Scelidotherium, and Glossotherium)-, a large
armoured animal related to the armadillo (later recognised as
Glyptodon); small armadillos; the rhinoceros-sized but anatomi-
cally enigmatic form Toxodon (a huge, lumbering notoungulate -
sometimes referred to as a "gigantic guinea pig"); Owen's "camelid"
Macrauchenia (in reality a litoptern, a member of a group of exclu-
sively South American ungulates that were anatomically and evo-
lutionarily convergent upon true camels); Mastodon augustidens
[Stegomastodon], an elephant-like proboscidean; hystricomorph
rodents; and, most remarkable of all, a true horse [Equus sp).
Darwin (and indeed Owen) was strongly impressed by a number
of facts linked to the 'dry' taxonomic observations about these fos-
sils: the clear biological relationship between the (generally) gigantic
but extinct forms and their modern counterparts; their compara-
tive uniqueness inasmuch as they were representatives of a truly
South American fauna; the comparative recency of their existence -
Darwin had been able to demonstrate that the majority of inverte-
brate (mollusc) fossils found with these extinct mammal bones were
similar to those still living today, which argued strongly for a very
recent period in Earth's history; as well as the extraordinary insight
into the history of the horse. Unknown to human civilisations in
South America prior to the arrival of the conquistadors, it was now
clear that ancestral Equus had become extinct in South America
in the geologically recent past. Such observations probed the heart
of heated debates in Paris between Georges Cuvier (1 769-1 832) and
Etienne Geoffroy Saint-Hilaire (1 772-1 844). Cuvier, a catastrophist
and functionalist (seeing all similarities in anatomy as products of
common adaptation to perform specific tasks) who envisioned a cre-
ative God sweeping all aside in mass-extinction events and then
repopulating the Earth de novo, was the counterpoint to Geoffroy
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134 SANDRA HERBERT AND DAVID NORMAN
(a disciple of Jean Baptiste de Lamarck [1744-1829]), who saw pro-
gression in time and continuity in nature: while Cuvier claimed
that the legs of man, mice, and lizards were similar because they
performed the function of walking (Desmond 1989), Geoff roy iden-
tified homology in such limbs - they all shared the same detailed
component bones and muscles, indicating a common blueprint for
all vertebrate animals; and this continuity could be demonstrated in
time as well as space.
Owen presented his first Hunterian lectures at the Royal College
of Surgeons in the summer of 1837 (Sloan 1992) and included men-
tion of the newly acquired Beagle specimens. Among these was the
large but enigmatic skull of Toxodon, which Owen had considerable
difficulty placing within his general understanding of the recognised
groups of Mammalia. The mystery skull had grinding teeth and a
wide diastema (the condition seen in modern rodents); it also had
nostrils that had migrated in position backward onto the top of its
snout (as they do in the skulls of elephants and whales). Clinging
to Cuvierian principles of comparative anatomy, Owen inevitably
concluded that Toxodon
manifests an additional step in the gradation of mammiferous forms leading
from the Rodentia, through the Pachydermata to the Cetacea. . . . (Owen
1840)
While this sounds almost evolutionary in its import, Owen was
approaching the placement of this mystery animal in the context
of a metaphor: a tree-like scaffolding, within which all mammals
could be represented. Owen advocated the view (first propounded
by Johannes Muller [1801-1858]) that extinctions were a reflection
of the "life-force" within all organisms: just as an individual lives
and dies, so too the species (i.e., "slothful" species use less energy
and persist for longer than "vigorous" species); equally, he proposed
that the past differences between species reflected their functional
integration with different regional and climatic conditions.
Darwin was caught up with many of these threads of debate and
discussion. He was actively meeting with Owen to talk over his
South American fossils, while Owen was simultaneously preparing
his Hunterian lectures (which Darwin may well have attended) and
presenting short papers on Darwin's fossils to the Geological Society
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Darwin's Geology 135
of London. Darwin was deeply impressed by the fact of extinction,
which his South American fossil mammals revealed. While being
aware of Muller's "life-force" idea, he was struck, on the one hand,
by the universality of some extinctions: what could have killed off
all the mastodons in the Northern and Southern as well as the East-
ern and Western Hemispheres, simultaneously? And why did the
horse go extinct in South America alone? On the other hand, he
was also struck forcibly by the geographic distinctiveness of this
fauna (both past and present). The latter became even more impor-
tant as he began to perceive the South American faunal influence
on the Galapagos Islands and the variability of species between the
islands.
Thus, by the early 1840s, through a series of vitally important
field observations and convenient fossil discoveries of his own, as
well as through direct exposure to the anatomical expertise of Owen,
linked to the deeply challenging philosophical struggles in which the
general discipline of comparative anatomy was embroiled, Darwin
was in an ideal position to rationalise and develop his own theo-
ries. While assiduously completing the reports on the findings of the
voyage of the Beagle (which took a decade after his return from the
Beagle voyage), he consciously developed his ideas in his notebooks
on the transmutation question and wrote preliminary drafts of his
species theory. Once his work on the Beagle material was complete,
he began new projects. In order to better understand the taxonomic
issues associated with the identity of species, he began his "barnacle
work," which blossomed into a comprehensive review of both living
and fossil species and provided an empirical foundation for his philo-
sophical development with respect to his later species work. All of
his work took place in the context of complicated intellectual and
institutional developments during the 1840s and 1850s, whose his-
tory has been the subject of numerous studies (Rupke 1994; Browne
2002).
THE ARGUMENT
In arguments it is often useful to lead from a position of strength
by placing one's most persuasive points first. In the Origin, Darwin
placed variation under domestication in his first chapter. By contrast,
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136 SANDRA HERBERT AND DAVID NORMAN
and tellingly, his treatment of the geological record is deferred until
Chapters 9 and 10. However, even in the first four chapters of the
Origin, where Darwin lays out his basic argument, geological points
surface from time to time.
The first case in which geology becomes a key point is in Chap-
ter 4, entitled "Natural Selection." Darwin was in the process of
arguing for the "continued preservation of individuals presenting
mutual and slightly favourable deviations of structure." He then
went on to compare the action of natural selection to the action of
geological forces, as they had been understood by his mentor Lyell:
I am well aware that this doctrine of natural selection, exemplified in the
above imaginary instances, is open to the same objections which were at
first urged against Sir Charles Lyell's noble views on "the modern changes
of the earth as illustrative of geology,-" but we now very seldom hear the
action, for instance, of the coast-waves, called a trifling and insignificant
cause, when applied to the excavation of gigantic valleys or to the forma-
tion of the longest lines of inland cliffs. Natural selection can act only by
the preservation and accumulation of infinitesimally small inherited modi-
fications, each profitable to the preserved being; and as modern geology has
almost banished such views as the excavation of a great valley by a sin-
gle diluvial wave, so will natural selection, if it be a true principle, banish
the belief of the continued creation of new organic beings or any great and
sudden modification in their structure. [Origin, 95-6)
Darwin took what he believed to be the widespread acceptance of
Lyell's claims for the efficacy of cumulative small changes to explain
large-scale phenomena in geology to add weight to his argument
that, in a similar fashion, small changes in individuals might over
the course of many generations cumulatively yield great changes in
morphology.
Within the core argument of the Origin, contained in the first
four chapters of the book, Darwin also raised the subject of extinc-
tion. While deferring full treatment until his later chapters on
geology, he wished to connect the issue to his core argument by
suggesting that as a consequence of high geometrical powers of repro-
ductive increase, each area is already "fully stocked" with inhabi-
tants. Therefore, "it follows that as each selected and favoured form
increases in number, so will the less favoured forms decrease and
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Darwin's Geology 137
become rare. Rarity, as geology tells us, is the precursor to extinc-
tion" [Origin, 109).
Immediately following Darwin's brief treatment of extinction in
Chapter 4 is a probing and philosophical discussion of an issue that
Darwin treated under the heading of "Divergence of Character." This
topic is treated separately in this volume, but it should be noted that
the fanning out of separate species groups was, like extinction, an
essential part of Darwin's explanation for the history of life on Earth.
From the point of view of arrangement of material, it is signifi-
cant that the one diagram in the Origin (frontispiece, p. ii) occurs
in Chapter 4, on natural selection, and that it both reflected and
shaped Darwin's perspective on the fossil record. The very notice-
able feature of this diagram is its high level of abstraction, for neither
species nor strata are labelled. While other contemporary authors
were attempting to express relationships of species across time, it
was usual to label groups and temporal boundaries. 1 By contrast,
Darwin's diagram is serenely abstract. (This was in contrast to sev-
eral of his earlier unpublished diagrams, which were more concrete
in their labelling.) 2 From bottom to top, the diagram represents the
passage of time from older to younger, but there is no beginning point
indicated. In the course of his book, Darwin suggested that there
must have been life before the lowest Silurian beds [Origin, 306).
(The lowest fossil-bearing strata were then known as "Silurian."
Darwin did use the term "Cambrian" in the fifth edition of the Ori-
gin [Variorum, 513] [Secord 1991].) Thus there is no representation
of an aboriginal group from which all else had sprung. Ultimately,
Darwin chose to leave this subject aside. It was, however, taken up
fairly quickly by his scientific peers in England after 1859 (S trick
2000). To some extent, of course, Darwin had raised the question
himself by his use of the tantalizing term "origin" in the title of his
book. He had contemplated entitling his book "On the Mutability
For reproduction of a number of these authors' works, see Barsanti (1992).
See Correspondence, 8: 379-80, for an example of a labelled diagram where Darwin
is speculating, with remarkable perspicacity, on details of the alternative patterns
of diversification (phylogenetic relationships) that might be exhibited by marsupial
and placental mammals. See also Bredekamp (2006) andVoss (2007 (for reproduction
of a range of Darwin's diagrams, some of which are labelled as groups, some of which
are more abstract.
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138 SANDRA HERBERT AND DAVID NORMAN
of Species," but ultimately decided in favour of the bolder "On the
Origin of Species." 3
Another noteworthy feature of the diagram is that Darwin was not
offering a transmutationist rendering of, say, Linneaus' Systema Nat-
urae. In his diagram, Darwin did not represent major units of plant
and animal classification. Further, he was flexible with regard to the
meaning of his symbols. His letters A through L were initially des-
ignated as standing for the "species of a genus large in its own coun-
try; these species are supposed to resemble each other in unequal
degrees, as is so generally the case in nature, and is represented in
the diagram by the letters standing at unequal distances" [Origin,
116). Later in the Origin, he wrote that the same letters A through L
on the figure "may represent eleven Silurian genera, some of which
have produced large groups of modified descendants" [Origin, 432).
Darwin's alternative lettering designations (species/genera) suggest
that the uses of argument for the diagram were paramount: its func-
tion was illustrative.
Darwin's representation of the passage of time in the diagram was
similarly flexible. In his chapter on "Natural Selection," he wrote
that "horizontal lines may represent each a thousand generations;
but it would have been better if each had represented ten thousand
generations" [Origin, 117). A few pages later, he allowed that
In the diagram, each horizontal line has hitherto been supposed to represent
a thousand generations, but each may represent a million or hundred million
generations, and likewise a section of the successive strata of the earth's
crust including extinct remains. [Origin, 124; also see 331)
Thus Darwin shifted easily, within the same sentence, between
describing the horizontal lines as representing a number of gener-
ations and having them represent strata. As he wrote it to his pub-
lisher John Murray when he submitted the diagram for inclusion
in his manuscript, "It is an odd looking affair, but is indispensable
to show the nature of the very complex affinities of past & present
animals" [Correspondence, 7: 300). If one keeps in mind the main
purpose of Darwin's diagram, as he saw it, the flexibility in its use
is understandable.
3 See DAR 205.1.70 for the alternative title page.
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Darwin's Geology 139
Despite the labile nature of his diagram, there is important infor-
mation in it regarding Darwin's conception of the pattern of life's
history. There are fewer forms represented at the bottom of the dia-
gram than at the top. This fanning out of forms was explained by
the principle of divergence. There are also forms represented that
have become extinct. As Darwin noted, all the forms beneath the
uppermost horizontal line may be considered as extinct. These two
principles - divergence and extinction - run through his presenta-
tion of the history of life. Presumed in this diagram is directionality,
though this was a complicated issue for Darwin as it was for his
contemporaries, particularly Lyell; we will return to it later as we
discuss the chapters devoted exclusively to geology.
Before leaving discussion of the core chapters of the Origin, we
wish to highlight Darwin's inclusion in them of two very concrete
references. While his overall strategy was to remain at a high level of
abstraction in the Origin, he did occasionally provide examples that
served as guides to his thinking and indicated his involvement with
the science of the day. Thus, in the final paragraph of Chapter 4, he
referred to two extant, but comparatively ancient, groups: the duck-
billed platypus [Ornithorhynchus) and the South American lungfish
[Lepidosiren).
As we here and there see a thin straggling branch springing from a fork low
down in a tree, and which by some chance has been favoured and is still alive
on its summit, so we occasionally see an animal like the Ornithorhynchus or
Lepidosiren, which in some small degree connects by its affinities two large
branches of life, and which has apparently been saved from fatal competition
by having inhabited a protected station. As buds give rise by growth to fresh
buds, and these, if vigorous, branch out and overtop on all sides many a
feebler branch, so by generation I believe it has been with the Great Tree of
Life, which fills with its dead and broken branches the crust of the earth,
and covers the surface with its ever branching and beautiful ramifications.
[Origin, 130)
While Darwin's depiction of the "Great Tree of Life" is metaphori-
cal, his inclusion of these two concrete examples gives his discussion
topicality. Ornithorhynchus (the duck-billed platypus) was an enig-
matic creature from Australia. Known from the very late eighteenth
century and originally asserted to be a hoax, it created taxonomic
confusion. The animal had mammalian fur, a duck-like beak, and
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140 SANDRA HERBERT AND DAVID NORMAN
was rumoured to lay shelled eggs like a typical reptile. Owen, who
had studied its eggs and mammary glands, favoured the view that it
was a mammal (Owen 1832, 1834). There were, however, differences
of opinion concerning this conflicting set of anatomical features, and
it was not until the 1880s that it was finally established that this
was a mammal that laid shelled eggs and yet suckled its hatched
young on milk that exuded from glands in folds on its abdomen.
Omithorhynchus had attracted Darwin's attention from early on.
In his transmutation notebooks from the 1830s he had speculated:
"Perhaps the father of Mammalia as Heterodox as ornithorhyncus,"
and "We have not the slightest right to say there never was com-
mon progenitor to Mammalia &. fish. When there now exist[s] such
strange forms as ornithorhyncus." Darwin believed Owen's treat-
ment of Omithorhynchus suffered from difficulties that occurred if
animals "are thought to have been created" [Notebooks, 192 [B, 89],
194 [B, 97], 370 [D, 115]). By citing Omithorhynchus in the Origin,
Darwin was drawing attention to a topical but unusual group whose
existence, he believed, was best explained by his own theory.
Lepidosiren, the South American lungfish, was described and
named by Leopold Fitzinger in 1 837. This was a timely debut for the
organism, given Darwin's interest in aberrant species. The lungfish
is an eel-like fish with tendril (thread-like) fins and normal inter-
nal gills within a gill chamber. It has the ability to gulp air into
its lungs at the water surface and to burrow down into mud during
the dry season, aestivating inside a cocoon. The origin of its name,
eliding as it does 'Lepido' (scaly) and 'Siren' (a mythical serpent),
represents an echo of its general resemblance to similarly enigmatic
New World animals known as sirens (amphibian, salamander-like
creatures [Siren and Pseudobranchus]), which had been known from
the mid eighteenth century and then "lately" described by James
Gray in 1826. They had similar habits and appearance, being purely
aquatic, and having a long eel-like body and an ability to gulp air into
their lungs. Sirens, unlike the lungfish, have permanent external
gills, rather than a gill chamber, and reduced limbs (rather than fins
or tendrils). These animals were outwardly remarkably similar and
presented the taxonomist with a challenge: what were they - fish,
saurian, or something in between? Darwin read Owen's 1841 arti-
cle on the lungfish and commented on them as connecting fish and
reptiles [Notebooks, 448 [E, 168]). When Darwin wrote the Origin,
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Darwin's Geology 141
the memory of them was still fresh, and he referred to Lepidosiren
and Ornithoihynchus as "in some small degree" connecting by their
affinities two large branches of life.
Darwin's full treatment of geology is contained in two chapters:
Chapter 9, "On the Imperfection of the Geological Record/' and
Chapter 10, "On the Geological Succession of Organic Remains."
There is also ancillary information on geology in Chapters 1 1 and
1 2 on geographical distribution, and in Chapter 1 3 on classification
and embryology.
Let us first look at what Darwin set out to accomplish in Chap-
ter 9. What he faced was a cohort of highly respected contemporary
palaeontologists and geologists who, he believed, were nearly unan-
imous in opposition to his views. As he wrote toward the end of the
chapter:
... all the most eminent palaeontologists . . . and all our greatest geologists
. . . have unanimously, often vehemently, maintained the immutability of
species. [Origin, 310)
Their most significant objection was that if "the number of interme-
diate varieties, which have formerly existed on the earth, be truly
enormous," then why does geology not reveal "any such finely grad-
uated organic chain." Darwin answered as follows: "The explana-
tion lies, as I believe, in the extreme imperfection of the geological
record" [Origin, 280). Darwin once wrote that he felt that his ideas
came "half out of Lyell's brains," and on no point was this more true
than on the subject of the imperfection of the geological record [Cor-
respondence, 3: 55). For both Darwin and Lyell, the greater portion
of the Earth's strata had been destroyed by the sea or worn away in
the process of the rise and fall of the Earth's crust. Following Lyell,
Darwin initially emphasized the role of the sea in shaping the land.
In the fifth edition of the Origin (1859), however, he placed more
weight on "subaerial degradation" [Variorum, 479 [39.1 :e]). What-
ever the agency, strata were destroyed, and the geological record was
thereby rendered imperfect.
In a transmutation notebook from the 1830s Darwin embraced
this view and aligned it with his theory on species:
Lyell's excellent view of geology, of each formation being merely a page
torn out of history, & the geologist being to fill up the gaps. - is possibly the
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142 SANDRA HERBERT AND DAVID NORMAN
same with the . . . philosopher, who has trace[d] the structure of animals &.
plants. - he get[s] merely a few pages. {Notebooks, 352-3 [D:6o])
In the Origin, he made the metaphor of the imperfection of the
fossil record central to his argument:
Those who think the natural geological record in any degree perfect, and
who do not attach much weight to the facts and arguments of other kinds
given in this volume, will undoubtedly at once reject my theory. For my
part, following out Lyell's metaphor, I look at the natural geological record,
as a history of the world imperfectly kept, and written in a changing dialect;
of this history we possess the last volume alone, relating only to two or
three countries. Of this volume, only here and there a short chapter has been
preserved; and of each page, only here and there a few lines. Each word of the
slowly-changing language, in which the history is supposed to be written,
being more or less different in the interrupted succession of chapters, may
represent the apparently abruptly changed forms of life, entombed in our
consecutive, but widely separated, formations. On this view, the difficulties
above discussed are greatly diminished, or even disappear. [Origin, 310-11)
This passage is one of the most important in the Origin, for upon it
rests Darwin's claim that it will never be the case that all, or even
the majority of, transitional forms will be found. While Sedgwick
(1830) had also compared the strata of the fossil record to pages in
a book, Darwin and Lyell pressed the analogy hard. Interestingly, in
discussing geology, Darwin brought in the analogy of the "slowly-
changing language" in which history is written. During the nine-
teenth century a great deal of research was being done on the subject
of historical linguistics and the genealogy of languages. Darwin drew
on this research in making his argument (Alter 1999).
Darwin sought to strengthen his argument for imperfection in
other ways. In the section of Chapter 9 titled "On the Lapse of Time,"
he argued for the vastness of geological time. What separated him
from the majority of his contemporary geologists was a willingness
to offer a numerical estimate for the time that had elapsed since
the formation of a well-studied portion of the stratigraphical record.
Lyell had supplied a description of the thickness of the stratigraphic
succession of the Wealden Formation of southeast England, but he
had not estimated the time since its formation. Darwin calculated,
using a denudation (erosion) rate of 1 inch (2.54 cms) per century,
that at least 3 00 million years were required to remove the overlying
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Darwin's Geology 143
deposits it had originally contained. Darwin's purpose in supplying
this estimate was not to date the geological record as a whole, much
less to assign a date to the age of the Earth, but to suggest "what an
infinite number of generations . . . must have succeeded each other
in the long roll of years!" [Origin, 287)
The next section in Chapter 9 is titled "On the Poorness of Our
Palaeontological Collections." Darwin argued that wide intervals of
time separated several geological formations, and he supplied a set
of geological explanations. Areas such as sea floors, deltas, and lakes
undergoing continuous (steady) subsidence would be expected to
show uninterrupted accumulations of sediment; by contrast, thick
deposits could not accumulate in shallow seas in which the under-
lying crust was stationary. In areas undergoing elevation, the ero-
sive action of the sea would wear away sediment. To this argument
regarding the vagaries of sedimentary accumulation (the necessary
condition for fossil burial) he added another that was congruent with
his ideas concerning the optimal conditions for the formation of new
species. He suggested that during the elevation of land "new stations
will often be formed," which promote the formation of new varieties
and species. Yet clearly and, in a sense, paradoxically, periods of ele-
vation are the ones during which erosion predominates: the rise in
land that promotes the creation of new species is logically inimi-
cal to their preservation as fossils. He concluded that "Nature may
almost be said to have guarded against the frequent discovery of her
transitional or linking forms" [Origin, 292).
The third section of Chapter 9 is titled "On the Sudden Appear-
ance of Whole Groups of Allied Species." From the point of view
adopted by contemporary geologists, this was a specially troubling
point. Darwin took two tacks in combating this objection. First,
arguing from a theoretical point of view, he suggested that while
it might take a long succession of ages for an organism to adapt
to some "new and peculiar line of life, for instance to fly through
the air, ... a comparatively short time would be necessary to pro-
duce many divergent forms, which would be able to spread rapidly
and widely throughout the world" [Origin, 303). Second, in an argu-
ment that would have been more persuasive to geologists, he pointed
out several cases where recent discoveries had shown that certain
groups of animals (all of the examples he cited were animals) had
been demonstrated to be present earlier in the geological record than
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144 SANDRA HERBERT AND DAVID NORMAN
had previously been known. Mammals were supposedly only to be
found in Tertiary rocks, yet Owen (1854) had described a veritable
'fauna' of fossil mammals from the Secondary (Cretaceous) rocks
of Dorset; these reinforced the observations of William Buckland
(1784-185 6) and others on fossil mammal jaws from the Jurassic of
Stonesfield (Buckland 1836). Contrariwise, the report of whale fossils
from the Upper Greensand by Lyell proved to be entirely mistaken.
While Darwin had posited a Tertiary origin for his sessile barnacles,
new evidence showed them to exist in Cretaceous (Mesozoic) rocks.
Teleost fish supposedly originated in the Chalk period, and yet evi-
dence was accumulating in palaeontological treatises, such as that
by Francois Jules Pictet de la Rive (1 809-1 872) and others, not only
that it was difficult to identify teleosts unambiguously, but that their
distribution in time was arguably more ancient than claimed. Hav-
ing cited these examples, Darwin concluded that given how little
of the world had been explored geologically, "it seems to me to be
about as rash in us to dogmatize on the succession of organic beings
throughout the world, as it would be for a naturalist to land for five
minutes on some one barren point in Australia, and then to discuss
the number and range of its productions" [Origin, 306).
The last section of Chapter 9 is titled "On the Sudden Appear-
ance of Groups of Allied Species in the Lowest Known Fossiliferous
Strata." Darwin here placed himself in opposition to the views of the
geologist Roderick Murchisonf 1 79 2-1 871), and others like him, who
believed that "we see in the organic remains of lowest Silurian stra-
tum the dawn of life on this planet" [Origin, 307). Darwin believed
that life existed much earlier. For example, he wrote that "I cannot
doubt that all the Silurian trilobites have descended from some one
crustacean, which must have lived long before the Silurian age, and
which probably differed greatly from any known animal" [Origin,
306). Why were the remains of these earlier organisms not preserved
in the fossil record? Here Darwin admitted he had "no satisfactory
answer," but he did allow himself to speculate. Taking note of the
fact that "no one oceanic island is as yet known to afford even a rem-
nant of any palaeozoic or secondary formation," he suggested that
oceans and continents have not always existed where they do today.
Should one then expect to find "palaeozoic" and "secondary" forma-
tions on the crust underlying the oceans? Not necessarily, answered
Darwin, "for it might well happen that strata which had subsided
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Darwin's Geology 145
some miles nearer to the centre of the earth, and which had been
pressed on by an enormous weight of superincumbent water, might
have undergone far more metamorphic action than strata which have
always remained nearer to the surface" ( Origin, 309). Metamorphism
would likely have destroyed the fossil evidence.
Chapter 10 of the Origin is titled "On the Geological Succession
of Organic Beings." This chapter has a strongly defined rhetorical
strategy. In it Darwin sought to show how his view ("slow and grad-
ual modification, through descent and natural selection") explained
the empirical facts of what was known of geological succession bet-
ter than did the "common view of the immutability of species."
[Origin, 312). His tack is understandable, since it was the facts of
geological succession that had in large part led him to espouse trans-
mutation in the first place (Herbert 2005). However, he was aware
that few contemporary geologists and palaeontologists were trans-
mutationists, so he trod carefully. Darwin also treated cautiously a
common belief that there was a law of development that governed
geological succession.
Darwin began by asserting that species, once extinct, never reap-
pear. This may seem an obvious point to a present-day reader, but it
was troublesome even to his confidant Lyell. His point was that each
species is modified by its history. So, even though physical condi-
tions identical to those existing earlier may return, and even though
the new species may "fill the exact place of another species in the
economy of nature," "yet the two forms - the old and the new -
would not be identically the same; for both would almost certainly
inherit different characters from their distinct progenitors" [Origin,
315): life was shaped by its history. He came back to this point later
in the Origin when he stated that the "simplicity of the view that
each species was first produced within a single region captivates the
mind. He who rejects it, rejects the vera causa of ordinary genera-
tion" [Origin, 352).
In his next section, titled "On Extinction," Darwin continued
the subject. After suggesting that the "old notion" of catastrophic
destruction of all inhabitants of the Earth at successive periods had
been "very generally given up" by palaeontologists, he turned to dis-
cuss his own experience in South America [Origin, 317-19). Know-
ing full well that the modern-day horse had been introduced into
South America by the Spaniards, he recalled marveling when he
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146 SANDRA HERBERT AND DAVID NORMAN
"found in La Plata the tooth of a horse embedded with the remains
of Mastodon, Megatherium, and other extinct monsters." But, he
reminds the reader, his astonishment was utterly groundless, for
Owen soon informed him that the horse was not identical to living
horses but was an extinct species. (For photographs of two speci-
mens of fossil horse teeth that Darwin collected, see Gardiner 2004.)
In Darwin's view, what had happened was simply that the earlier
South American horse had become rare to the point of extinction:
that was its history. If the horse tooth had come from a presently
living species, Darwin could have accommodated that possibility as
well (given the existence of modern mollusc shells), though it would
have required slightly more complicated reasoning.
More complicated reasoning was indeed required in the next sec-
tion, titled "On the Forms of Life Changing Almost Simultane-
ously throughout the World." Darwin did not challenge this notion.
Rather, he asserted that "this great fact of the parallel succession of
the forms of life throughout the world is explicable on the theory of
natural selection." He argued that the "dominant, varying, and far-
spreading species, which already have invaded . . . the territories of
other species, should be those which would have the best chance of
spreading still further." He allowed that diffusion would "be slower
with the terrestrial inhabitants of distinct continents than with the
marine inhabitants of the continuous seas." [Origin, 325-6). World-
wide change in marine species would occur more easily and quickly
than worldwide change in terrestrial species.
The next section of Chapter 10 is titled "On the Affinities of
Extinct Species to Each Other, and to Living Forms." This is one of
the strongest sections in the Origin. Darwin opened it by comment-
ing with elegant simplicity that extinct and living species "all fall
into one grand natural system; and this fact is at once explained on
the principle of descent" [Origin, 329). He then invoked for support
the views of Buckland, Owen, Cuvier, Pictet de la Rive, and Joachim
Barrande (1 799-1 883) on particular points. Further on in the Origin
he returned to the theme of "one natural system" when he discussed
the subject of classification. He wrote, in Chapter 13, that "the nat-
ural system is founded on descent with modification," and that "all
true classification is genealogical" [Origin, 420).
In Chapter 10, under the heading "On the State of Development of
Ancient Forms" Darwin also broached the question of whether the
fossil record shows progression. He concluded that "in one particular
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Darwin's Geology 147
sense the more recent forms must, on my theory, be higher than the
more ancient; for each new species is formed by having had some
advantage in the struggle for life over other and preceding forms"
[Origin, 337). In this section Darwin also addressed the question of
whether, as Agassiz thought, "ancient animals resemble to a certain
extent the embryos of recent animals of the same classes." Darwin
was conciliatory on this point, seeing its potential compatibility
with his own views while at the same time suggesting that Agas-
siz's claim of a parallel between embryological development and
geological succession had not yet been proven [Origin, 338).
In the last section of Chapter 10, "On the Succession of the Same
Types within the Same Areas, during the Later Tertiary Periods,"
Darwin reiterated his view that the theory of descent with modi-
fication explained the similarity of fossil and recent species in the
same geographical area, "for the inhabitants of each quarter of the
world will obviously tend to leave in that quarter, during the next
succeeding period of time, closely allied though in some degree mod-
ified descendants" [Origin, 340). In this section he also attempted to
respond to critics who, in ridicule, had asked whether such present-
day South American species as the sloth, armadillo, and anteater
were "degenerate" descendants of the "megatherium and other allied
huge monsters" [Origin, 341 ). His answer was an emphatic "no," for
he was skeptical concerning laws of either development or devolu-
tion. To explain the living South American species he appealed to
the existence of collateral lines of extinct animals, more similar to
current species than were the "huge monsters" of the past.
Thus concludes Darwin's treatment of geology per se. However,
in Chapters 1 1 and 12 on geographical distribution many of the same
themes recur. For example, since Darwin insisted that each species
had come into existence only once, the question of means of dis-
persal was key for him; that subject is fully treated in Chapters 1 1
and 12. Darwin also gave considerable attention in those chapters to
discussion of "Dispersal during the Glacial Period" [Origin, 365-82).
In summary, we can say that in the first edition of the Origin Dar-
win was on the defensive because of the evident paucity of the fos-
sil record in the 1850s. He used generalised arguments that probed
a fundamental issue, which was whether geological history better
supported the view that species were immutable or the view that
species exhibited "slow and gradual modification." For the most part
he relied on the changing opinions (initially anti- but increasingly
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148 SANDRA HERBERT AND DAVID NORMAN
pro-transformation) of well-regarded authorities such as Lyell. Mak-
ing the general observation that rocks of more recent age contained
fossil species still recognisable as living today, and that the further
back in time one went the larger the percentage of extinct species,
he nevertheless strove, wherever possible, to demonstrate that there
were no developmental laws governing species duration.
This view was integrated with Darwin's more general perception
of extinction. Contrary to the serial universal catastrophe (mass-
extinction) claims of Jean Baptiste Elie de Beaumont (179 8-1 874),
Murchison, and Barrande (and before them of Cuvier and Buckland),
it was increasingly being seen that species and groups of species dis-
appeared gradually and intermittently across long periods of time
and that their individual durations varied enormously. Although he
was careful to report the "sudden extermination" of some large and
widespread groups such as the trilobites at the end of the "palaeozoic
period" (Paleozoic Era) and the ammonites at the close of the "sec-
ondary period" (Mesozoic Era), Darwin's personal experience of the
fact of extinction related to his fossil mammals of South America:
notably, the loss of the horse, which prompted him to consider the
many and varied influences (lost to our knowledge today) that might
have promoted its decline on that continent but not elsewhere. In
this way extinction became for Darwin the norm, a necessary coun-
terpoint in the "struggle for existence" to the continuous origination
of new species.
If one were to translate his ideas into present-day terms, Darwin
imagined new terrestrial species arising relatively quickly, particu-
larly in suitable areas, such as those undergoing elevation. At the
other end of the scale, he expected that species would die out com-
paratively more slowly. This process is similar to what would today
be termed a 'clade spindle': each species' duration being depicted as
a fusiform shape oriented vertically in space, indicating its origin at
a point in time, with a phase of rapidly increasing abundance until
it reaches a maximum before dwindling to its extinction.
After Publication
The influence of the publication of the Origin on the fields of geol-
ogy and palaeontology was profound and immediate, and Darwin's
response correspondingly nimble. Darwin's estimate of the time
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Darwin's Geology 149
necessary for the denudation (erosion) of the Weald was criticized
sharply. To take only one example, the Oxford palaeontologist John
Phillips ( 1 800-1 874) reviewed the Origin in his February 17, i860,
presidential address to the Geological Society of London. He accused
Darwin of "abuse of arithmetic" in his calculation of a figure for the
denudation of the Weald and suggested alternative computations.
Darwin responded by reducing the period for the denudation of the
Weald from 300 million years to between 100 and 150 million years.
He then dropped the estimate entirely from the third and subse-
quent editions (Herbert 2005; Morrell 2005 ). While Darwin's original
estimate did not survive, it did promote attention to the question
of absolute geological time and the duration of the stratigraphical
succession.
As he revised the Origin Darwin also added new material reflect-
ing progress within the field of geology. One area that had been an
early difficulty for him was glacial theory. For this reason he tracked
the issue closely, being particularly attentive to the theories being
put forward by James Croll (1 821-1890). Croll posited that changes
in the Earth's orbit had been the cause of glacial periods. While
Darwin had always left the door open to extraterrestrial influences,
his usual focus, like that of Lyell, had been the forces operating
within an Earth-bound system. By the 1860s, glacial theory required
a step away from that focus, and Darwin incorporated Croll's ideas
into the fifth edition of the Origin [Variorum, 593 [215.2:0]; Corre-
spondence, 16, part II: 873-6).
Yet of all the geological subjects contained in the Origin, palaeon-
tology was the most important. And here even Darwin's supporters
had qualms. Speaking as an evolutionist, Thomas Henry Huxley
(1825-1895) noted the intervals or gaps between " very distinct
groups: - Insects are widely different from Fish - Fish from Rep-
tiles - Reptiles from Mammals - and so on." He asked why the gaps
exist and where might be the connecting forms:
Among the innumerable fossils of all ages which exist, we are asked to point
to those which constitute such connecting forms. Our reply to this request
is, in most cases, an admission that such forms are not forthcoming, and we
account for this failure of the needful evidence by the known imperfection
of the geological record. We say that the series of formations with which we
are acquainted is but a small fraction of those which have existed, and that
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150 SANDRA HERBERT AND DAVID NORMAN
between those which we know there are great breaks and gaps. I believe that
these excuses have very great force; but I cannot smother the uncomfortable
feeling that they are excuses. (Huxley 1868, 358)
From Huxley's point of view the most satisfactory way to relieve
that "uncomfortable feeling" was to fill some of those gaps, which,
indeed, was the point of his article, titled "On the Animals which
Are Nearly Intermediate between Birds and Reptiles." The centre-
piece of Huxley's article was Archaeopteryx, which he presented as
a candidate for a group linking birds and reptiles.
In the third (1861) edition of the Origin Darwin had taken up
the question of bird origins. Birds had been thought to be early Ter-
tiary (Eocene) in origin, but Owen had recently identified bird fossils
in the Upper Greensand (Mesozoic Era). (Subsequently these bones
were shown to be the remains of flying reptiles [pterosaurs].) Darwin
was also able to refer to evidence from publications by Edward
Hitchcock (1793-1864) on the supposed bird footprints from the
much more ancient (New Red Sandstone) Connecticut Valley. By
the fourth edition (1866) Darwin was able to add, in the paragraph
on bird origins, the evidence again provided by Owen (1863) of the
ancient (Jurassic Period) "strange bird" Archaeopteryx, noting par-
ticularly the presence of claws on its wings and a long lizard-like
tail. In the fifth (1869) edition of the Origin Darwin called attention
to Huxley's findings linking "on the one hand, the ostrich and the
extinct Archeopteryx, and on the other hand, the Compsognathus,
one of the Dinosaurians" [Variorum, 509 [194.11b, 194. \:b, 194.4:^],
540 [137.2:6, 137.2:/]).
The case of the bird Archaeopteryx and the allied dinosaur Comp-
sognathus compels interest because of the timing of the discoveries
in relation to the publication of the Origin and the way it inter-
weaves the views of Owen, Darwin, and Huxley. Building on work
by earlier researchers, Owen had 'invented' dinosaurs in 1842 as
very large, quadrupedal pachyderm-like reptiles (the zenith of ver-
tebrate form during the "secondary period" [Mesozoic Era]) and cre-
ated a lasting image of these as life-sized models in 1854 at the
Crystal Palace Park in London (Delair and Sarjeant 1975; Desmond
1975, 1979). Compsognathus was an almost complete, chicken-sized
skeleton discovered, in somewhat mysterious circumstances, in the
mid-18 5 os in a lithographic limestone quarry near Solnhofen in
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Darwin's Geology 151
Bavaria. The dinosaur was named by Andreas Wagner (1 797-1 861)
in 1859. The celebrated remains of Aichaeopteiyx were found in a
nearby quarry in the same limestone formation; the first discovery
(i860) was a feather impression, and a year later a partial skeleton,
with associated feather impressions, was recovered. This was pur-
chased by the British Museum in 1 862 and studied, with remarkable
speed, by Owen - the specimen arrived on October 1, 1862, and its
description was received by the Royal Society on November 6, 1862
(de Beer 1954). Owen declared it to be a fossil bird in almost all
its anatomical attributes (Owen 1863), but one that differed from
living birds in two unusual features: a long, bony tail (more rem-
iniscent [to Owen's eyes] of the unfused embryonic tails of living
birds) and claws on its wings (explained as a relatively common
variation, given that digits are found on the wings of bats, flying
lemurs, and flying reptiles). During the 1860s, Huxley became inter-
ested in dinosaurs, birds, and Aichaeopteiyx. In his haste to describe
Aichaeopteiyx, Owen had made a rather fundamental error in mis-
taking the upper for the lower side of the animal (allowing Huxley
some simple point scoring). More crucially, his investigations of the
anatomy of some well-known dinosaurs [Megalosauius and Iguan-
odon) began to reveal some equally fundamental mistakes in the
identification of the pelvic bones, which took on a decidedly avian
form; these observations, linked with the relatively complete but
small and superficially bird-like Compsognathus, provided Huxley
with an argument that responded to the accusations of Darwin's
detractors concerning the absence of intermediary forms in the fos-
sil record.
Bird anatomy was highly specialised, unique, and very different
from that of reptiles; this justified their separation into different
vertebrate classes (Aves and Reptilia). Owen had already demon-
strated that Aichaeopteiyx exhibited a range of uniquely avian fea-
tures. However, in Huxley's opinion the long bony tail and sepa-
rate bones and claws on its hands represented reptilian traits (rather
than embryonic avian traits or functional convergences). Further-
more, when Huxley compared the anatomy of known large, land
birds (ostriches) to that of dinosaurs he was able to demonstrate a
surprising number of similarities (notably in the detailed structure
of the sacrum, pelvis, and hind limbs); and, added to this, observa-
tions of the most bird-like (and anatomically complete) of the known
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152 SANDRA HERBERT AND DAVID NORMAN
dinosaurs, Compsognathus, seemed completely to accord with this
novel view.
Alluding to the Triassic footprints of bird- like animals from Con-
necticut described by Hitchcock in 1 85 8, Huxley suggested that dur-
ing the "secondary period" (Mesozoic Era) there must have existed
a range of bird-like dinosaurs and dinosaur-like birds that formed a
range of evolutionary intermediates between two great (and appar-
ently widely separated) classes of vertebrates. In Huxley's words:
It can hardly be doubted that a lithographic slate of Triassic age would yield
birds so much more reptilian than Archaeopteryx, and reptiles so much
more ornithic [bird-like] than Compsognathus, as to obliterate completely
the gap which they still leave between reptiles and birds. (Huxley 1868, 365)
Discoveries over the latter decades of the nineteenth century mostly
confirmed Huxley's predictions: several dinosaurs were discovered
that exhibited very bird-like characteristics. There was, however,
a prolonged period (the 1920s to the 1970s) following the publica-
tion of a detailed review of the subject by Gerhard Heilmann during
which dinosaur-bird (ancestor-descendant) affinities were doubted
on the basis of some anatomical inconsistencies. It was not until the
description by John Ostrom in the 1960s of Deinonychus, another
remarkably bird-like theropod dinosaur (Ostrom 1969) that Huxley's
theory was resuscitated (Ostrom 1976). Since then, Huxley's percep-
tive commentary has been amply confirmed by the discoveries in
China since 1997 of a remarkable diversity of filament-covered and
in some instances genuinely feathered dinosaurs. These new discov-
eries have partially fulfilled his goal of finding "reptiles so much
more ornithic."
In summary, the six editions of the Origin demonstrate that
Darwin was deeply involved with geology and the closely allied field
of palaeontology. This book lay down a gauntlet that challenged and
ultimately transformed both fields of research.
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PETER J. BOWLER
Geographical Distribution
in the Origin of Species
I. GEOGRAPHY AND ITS IMPLICATIONS
In 1845, Darwin wrote to Joseph Dalton Hooker predicting that he
(Hooker) would soon be recognized as the first authority in Europe
on "that grand subject, that almost key-stone of the laws of cre-
ation: Geographical Distribution." 1 Darwin had already included a
substantial section on the topic in his "Essay" of 1844 and would
interact extensively with Hooker on the topic over the next decade
and more. The Origin of Species itself contains two chapters on dis-
tribution, occupying sixty-four pages, or just over 1 3 percent of the
text of the first edition. These two chapters would be modified on
minor points in the subsequent editions, but would remain essen-
tially intact, serving as one of the main lines of support for his theory.
Since they include his discussion of the distribution of species on
the Galapagos Islands, they represent a key link in the process by
which the theory was developed and then presented to the public.
It has always been recognized that the study of how species are
located around the globe, on both a small and a large scale, was a
key line of evidence leading Darwin toward the theory of common
descent. The idea that divergence from a common ancestor was gen-
erated by a process that adapted populations to changes in their local
environments (physical or organic) would eventually serve as one of
his most convincing arguments in favour of natural selection. Cou-
pled with the proposal of plausible hypotheses about how members
of a species could be transported from one area to another, the theory
1 Darwin to Hooker, February 10, 1845, in Correspondence, 3: 140.
153
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154 PETER J. BOWLER
would account for a host of facts about distribution that had become
increasingly puzzling as more evidence was built up by exploration
of remote regions of the globe.
But in order to understand Darwin's arguments on the topic, we
need to be clear about his intentions. More specifically, we need to
recognize how limited those intentions were - in a sense, to real-
ize what he was not trying to do. Later in the century evolution-
ists would incorporate geographical evidence into their efforts to
reconstruct the history of life on Earth. In the 1870s, Alfred Russel
Wallace, who had also been inspired by the topic to become a trans-
mutationist, compiled a massive two-volume survey, The Geograph-
ical Distribution of Animals, backed up by a later volume on Island
Life. 1 Over the next few decades there was a flurry of interest from
scientists who used the geographical distribution of living and fossil
species to indentify the points of origin, and subsequent migrations
and extinctions, of all the major groups of animals and plants. 3 But,
as with his analysis of the fossil record in the Origin, this was not
Darwin's project. He doubted that the fossil evidence would ever
be sufficient to allow a complete reconstruction of the course of
life's development. He discussed the fossil record in order to head off
claims that its discontinuity counted against evolution, and to show
that when trends could occasionally be identified, they matched the
predictions of his theory.
The point I want to drive home is that these are exactly parallel
to the arguments he would apply to the evidence from geographical
distribution. There was to be no attempt to reconstruct the origins
and migrations of all the major groups, no comprehensive survey
of the geography of life. What Darwin did was to choose a small
number of examples of distribution about which enough evidence
had become available, and to show that the patterns made perfectly
good sense in terms of his own theory but no sense at all on the
basis of special creation. In particular, he was concerned to refute
the idea that to explain cases where the same species existed in
two or more widely separate regions, it was necessary to invoke the
multiple creation of identical parent forms. Darwin's case was that
as we gain more knowledge of the processes by which living things
2 Wallace (1876, 1880).
3 Outlined in Bowler (1996), Chapter 8.
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Geographical Distribution in the Origin 155
can move around the globe, we see how such cases can always be
explained by dispersal rather than by multiple creation. In order to
do this, he was willing to invoke limited geographical changes in the
course of geological time. But even when postulating geographical
and climatic changes on a global scale, he always focused on specific
test cases. He did not think it would be possible, in practice, to
make a complete reconstruction of the history of life on Earth. The
vast project to undertake such a reconstruction, inspired by Ernst
Haeckel and eventually applied to biogeography by Wallace and his
successors, was not part of Darwin's research program.
11. darwin's early ideas
This is not the place for a detailed study of Darwin's response to
the discoveries on the Galapagos Islands or the other biogeograph-
ical insights he gained while on the Beagle voyage. But once he
had formulated his theory of natural selection in the late 1830s, he
immediately began to use case studies from biogeography as part of
the argument he would construct to defend the theory. In its initial
form, as displayed for instance in the "Essay" of 1844, the theory
incorporated several points that Darwin would eventually abandon
before writing the Origin. Janet Browne has nicely described these
developments, so they will only be summarized briefly here. 4 There
were two key changes. First, Darwin gradually abandoned his early
enthusiasm for massive elevations and depressions of the Earth's
surface in the course of geological time, which had initially led him
to think that whole continents could be submerged beneath the sea
and then re-elevated. By the time he wrote the Origin, Darwin was
convinced that the present distribution of the continents and oceans
was permanent, at least as far back as the Mesozoic. And secondly -
but only in the last years before he was precipitated into writing the
Origin - he developed his "principle of divergence," which led him
to place much less emphasis on the need for geographical disper-
sal on islands to initiate speciation. The Galapagos situation would
become only a special case of divergence, not a model for how it nor-
mally took place. By 1859, Darwin thought that the splitting apart
of species normally took place on large landmasses.
4 See Browne (1983), Chapter 8; also Browne (1995), pp. 5 14-21.
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156 PETER J. BOWLER
Chapter 6 of the 1844 "Essay" offers several classes of phenom-
ena for analysis. As Darwin eventually makes clear, his purpose in
discussing these areas is to show that they all display unexpected
features that the creationist (and he uses that term) has to accept as
"just ultimate facts" for which there is no rational explanation. But
surely, he argues, we should be searching for general laws, and that
is what he eventually moves on to do. 5
The first topic of interest is the distribution of the inhabitants
of the different continents. 6 Here he notes the efforts that had
been made to define biogeographical regions - five is his preferred
number - and that these are defined by the major geographical bar-
riers, especially deep oceans where the seabed is unlikely ever to
have been raised above the surface. He notes that tropical Africa
and South America have very different inhabitants, despite exhibit-
ing the same range of physical environments. This is not what we
would expect if species were designed by a supernatural Creator to
be perfectly adapted to their environments. Later in the chapter he
points out that these characteristic differences can be seen in the
fossils unearthed in the same regions. Even more strikingly, how
can the creationist explain why marsupials are found only in Aus-
tralia and South America? His interest in these striking differences
in the distribution of species was, of course, stimulated by his own
experiences on the Beagle voyage.
The Beagle discoveries also come to the fore in his next topic:
insular floras and faunas. If species are separately created, why is
it that the inhabitants of oceanic islands always resemble those of
the nearest mainland? Why are the Galapagos species characteristi-
cally South American, and why are there different but related species
on many of the individual islands? 7 A parallel phenomenon can be
found in the case of floras of mountainous regions (alpine floras),
which are often identical even on widely separated peaks. Curiously,
the same species are often found far to the north in Arctic regions. In
other cases, similar species can be found in places widely scattered
and separated by oceans. Darwin's explanation of these anomalous
distributions closely follows the one that would be published by
5 Darwin and Wallace (1958), pp. 192-4.
6 Ibid., pp. 169-75.
7 Ibid., p. 176.
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Geographical Distribution in the Origin 157
Edward Forbes in 1846. 8 Inspired (like Darwin) by Charles Lyell's
uniformitarian geology, Forbes appealed to the evidence of a period
of intense cold in the recent past (which would become known as
the Ice Age) to argue that during such a period Arctic plants would
migrate south. When the climate warmed again, they would retreat
northward, but would also move to higher elevations in mountain-
ous regions of the southern localities they had temporarily occupied.
These isolated populations would end up stranded on the peaks,
like islands separated by a sea of lowland in between. Darwin also
invoked icebergs as a possible means by which Arctic plants could
be transported from the North to isolated areas in the Southern
Hemisphere.
Darwin then reveals why he is so interested in these relationships.
Because there seemed no prospect of these species having migrated
from one place to another across the hostile lowlands in between,
the phenomenon of disjunct species was widely taken as the best
evidence not only of divine creation, but also of the fact that the
same species could be created in more than one location. 9 Darwin's
extension of the Ice Age theory has thus provided a clear alternative
to the creationist position, which he reinforces by pointing out our
extreme ignorance of the means by which species can be dispersed -
which might conceal other possible explanations of anomalous
distributions. He also notes that mammals, which can obviously
migrate more readily than plants, do not show the same anomalies,
although on the theory of multiple creations there is no reason why
they too should not be created in more than one location. All the
evidence, he argues, points to each species having a single point of
origin and then spreading out to occupy whatever territory it can
gain access to. Only prior occupation by another species exploiting
the same resources might prevent a newcomer from successfully
colonizing new territory.
Darwin has, in effect, called in the gradual modifications of cli-
mate postulated by Lyell's uniformitarian geology, coupled with
8 Ibid., pp. 1 80-1. On the similarity between Darwin's and Forbes' s views, see Browne
(1983), p. 12,1, and Bowler (1992), pp. 275-80.
9 Darwin and Wallace (1958), pp. 185-6. Louis Agassiz was widely recognized as the
most active exponent of the idea of multiple creations, although Darwin does not
name him.
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158 PETER J. BOWLER
the hope of extending our knowledge of dispersal mechanisms, to
explain the anomalies of distribution that must remain just brute
facts to the creationist. As noted earlier, however, Janet Browne has
pointed out that some aspects of his explanation differ consider-
ably from what he would later offer in the Origin. Although Darwin
already appreciated the significance of deep oceans as more or less
permanent barriers to migration (and hence as defining the main bio-
geographical regions), at this point he still believed it was possible for
geological forces to produce gradual, but significant, changes in the
elevation of any point on the Earth's crust. The theory he offered in
1 839 to explain the "parallel roads of Glen Roy" in Scotland assumed
that these ancient beaches were formed at a time when Europe was
temporarily submerged to a large extent beneath the ocean. 10 He
was also convinced, in part by the example of the Galapagos fauna,
that the most favourable circumstances for speciation (the split-
ting up of one species into a number of related 'daughter' species)
occurred when a population was divided up among isolated islands.
At this point in his career, he was convinced that adaptive vari-
ations would appear only very rarely. Although there would be a
better chance of such favoured individuals appearing in a widely
distributed population, they would have to interbreed with a large
number of unchanged individuals, and this would effectively swamp
the innovation. In a small island population, on the other hand, the
rare individual variant's effect would be concentrated by inbreeding
and would thus more readily cause the population to diverge from
the parent type.
As a consequence of these assumptions, in 1844 Darwin put for-
ward a theory in which both the production and the dispersal of new
species depended on slow but constant changes in the land surface
brought about by geological forces. 11 He envisaged continental areas
being alternately lowered beneath the sea and then raised again. In
the course of submersion, the continent would slowly be split up
into a number of isolated islands, which would gradually diminish
in size and be split up further. When the once- widespread population
was broken up among many islands, each subpopulation would adapt
10 On Darwin's Glen Roy theory and his subsequent acceptance that the Ice Age
provided a better explanation, see Martin J. S. Rudwick (1974).
11 Darwin and Wallace (1958), pp. 195-203.
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Geographical Distribution in the Origin 159
to the new conditions in its own way, and there would be extensive
speciation. When the continent once again emerged from beneath
the sea, the islands would gradually merge together, and the species
originally confined to them would disperse and come into conflict
with one another. Eventually, the most successful of them would
occupy wide areas, as we find on the continents today. But once
this equilibrium was reached, there would be little further change
until the next episode of submergence. Evolution thus depended on
submergence and fragmentation of the land surface, while dispersal
depended on the subsequent opening up of land connections to allow
outward migration.
III. DEVELOPMENTS BEFORE THE ORIGIN
Over the next decade, Darwin worked on topics that he knew would
provide additional support for his theory. These included gathering
information about geographical distribution and the means by which
various types of organism could be distributed from one region to
another. He interacted with a number of fellow naturalists who were
interested in these topics, especially if they were prepared to follow
the Lyellian model of dispersal coupled with gradual geographical
and climatic changes. On botanical matters, he formed a close link
with Joseph Dalton Hooker, who - as noted in the letter quoted
earlier - he anticipated would become the leading European expert
on distribution. Asa Gay would eventually fill the equivalent role in
America, and both men would eventually be informed of the radical
nature of Darwin's views on species. Alfred Russel Wallace would
also interact with Darwin, although not in a manner that allowed
Darwin to realize the full extent to which their views were moving
in the same direction.
Eventually Darwin began to write his "Big Book" on species,
which would eventually be cut down to form the Origin of Species.
This too contained a section on geographical distribution, the
manuscript of which was sent to Hooker for comment in 1856. 12
In this chapter Darwin was mainly concerned to outline and extend
Species Book, Chapter 11. For the editor, Robert Stauffer's, analysis, see pp. 528-35.
Darwin evidently intended to write another chapter on the topic, but this either
was not produced or has not survived.
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l60 PETER J. BOWLER
his account of the dispersal of Arctic forms during the Ice Age, turn-
ing it ; in effect, into a global theory centered on the possibilities of
dispersal during this period of anomalously cold climatic conditions.
He comments on the uniformity of Arctic species around the high
latitudes of the Northern Hemisphere, something made possible by
the close connection between Eurasia and North America. He even
seems to accept Edward Forbes's suggestion that there might once
have been a land connection across the North Atlantic. 13 He also
endorses Forbes's idea that much of Europe was submerged beneath
the sea at some point during the period of cold conditions, plants
being transported from one island to another by icebergs. The islands,
of course, would become mountains on subsequent re-emergence of
the land.
Darwin also accepts the possibility that - assuming both hemi-
spheres endured cold conditions at the same time - icebergs could
transport plants or their seeds across the equator to establish popula-
tions of northern plants in remote areas of the South, such as Tierra
del Fuego and Kerguelen Island. His concluding remarks make it
clear that his main target is still the theory of the independent cre-
ation of these isolated populations. He argues that the possibility of
migration (especially given our ignorance of the modes of transporta-
tion) is strong enough to undermine the case for multiple creations in
distinct areas. If one could identify two identical populations exist-
ing in regions where there was no possibility of migration, then "the
whole of this volume would be useless &. we should be compelled
to admit the truth of the common view of <absolute> actual cre-
ation." 14
Hooker did not think the transport of plants by icebergs very
plausible (he had observed icebergs firsthand in his own Antarctic
travels). He was more inclined to propose an extension of the land
surface in the distant past, generating 'land bridges' across which
plants could migrate by more traditional means. 15 He certainly felt
that more information was needed on means of dispersal, unaware
13 Ibid., pp. 536-8.
14 Ibid., p. 566.
15 Hooker to Darwin, August 4, 1856, and August 7, 1856, in Correspondence, 6:
198-200, 203-204. Hooker would continue to defend the idea of a great Antarctic
continent through the 1880s; see Bowler (1996), p. 413.
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Geographical Distribution in the Origin 1 6 1
that Darwin was working on such a project. In a detailed response
to Darwin's 1856 manuscript, Hooker confessed that he had been
impressed by the evidence for change in the natural world and had
"never felt so shaky about species before." 16 He suggested many
ideas on how to extend the theory of migration by bringing in factors
such as the direction of ocean currents (he was now less opposed to
the possibility of transport by icebergs).
As Janet Browne points out, by the time he wrote the Origin of
Species, Darwin's ideas on speciation and dispersal would be very
different from those expressed in 1844 and 1856. 17 He was becom-
ing convinced that the geographical breaking up of a population onto
separate islands was not essential for speciation. Islands certainly did
generate species, of course, as in the case of the Galapagos, but he
now conceived his 'principle of divergence' according to which the
competition for resources within a single continuous habitat would
produce diverse forms that could exploit the environment in differ-
ent ways. Evolution could thus occur on a continental land mass,
and indeed would take place more readily there than on islands.
At the same time, Darwin was becoming increasingly uncomfort-
able with his earlier assumption that geological changes had pro-
duced drastic elevations and depressions of the Earth's surface. It
was unlikely that Europe had been largely sunk beneath the ocean
as recently as the last Ice Age (thus undermining his Glen Roy the-
ory) and equally unlikely that areas of what is now ocean had been
elevated to form 'land bridges' between the existing continents in
the recent geological past. This threw increasing emphasis onto the
means of dispersal of land animals and plants across the oceans, and
if icebergs were not a plausible mechanism of transport, it would
be necessary to investigate what alternative means might exist. By
the time he wrote the Origin, Darwin had become far more aware
of the possibility that apparently unlikely processes could, in fact,
aid dispersal and thus be used to explain how a species evolved in
one area could spread to distant locations. He now had a theory
that depended less on environmental change to drive speciation, but
still appealed to the possibility of different conditions in the past to
explain distribution. Another naturalist working along similar lines
16 Hooker to Darwin, November 9, 1856, in Correspondence, 6: 259-64.
17 Browne (1980, 1983).
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I 62 PETER J. BOWLER
was Alfred Russel Wallace, and in 1858 Wallace's famous paper trig-
gered Darwin's rush to complete the single-volume account of his
new theory that became the Origin of Species.
IV. GEOGRAPHICAL DISTRIBUTION IN THE FIRST
EDITION OF THE ORIGIN
The two chapters on distribution in the Origin (Chapters 1 1 and 1 2 in
the first edition) pick up on themes explored in the 1 844 "Essay" but
explain Darwin's new approach to the topic. The basic aim remains
the same, however: to challenge the evidence for divine creation by
showing that there are phenomena that cannot be explained on that
basis, but that can be understood on the assumption that species
evolve in a single location and then disperse to other localities.
Darwin begins once again by noting the differences between the
inhabitants of the various continents, especially between those of
Africa and South America, even though they often exhibit exactly
the same range of habitats. It is the geographical barriers that define
the regions, with the oceans being the most permanent - although
other barriers, including rivers and deserts, can also be effective on
a shorter time scale. He also notes the affinity between the inhab-
itants of oceanic islands and those of the nearest continent. There
is "some deep organic bond, prevailing throughout space and time,
over the same areas of land and water, independent of their phys-
ical conditions." 18 This bond is simply inheritance, the only thing
we positively know can produce such affinities. Darwin's point, of
course, is that divine creation offers no such explanation because
there is no reason why miracles should be constrained by geographi-
cal barriers. Later on in the chapter he repeats the example of oceanic
islands and notes that Wallace has postulated (in his 1855 paper) that
species always appear in a region where there is a preexisting allied
species. 19
In a significant modification to the explanation offered in 1844,
though, Darwin stresses the role of competition in determining
which species will spread out most successfully to occupy neighbor-
ing territory. Wide-ranging species that have triumphed over rivals
18 Darwin (1859), p. 350.
" Ibid., p. 35 5-
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Geographical Distribution in the Origin 163
will have the best chance of occupying any new territory they can
migrate to, although even they may be checked if another species
adapted to the same mode of existence is already in occupation. He
emphasizes that there is no law of necessary development, so species
need not change if they move to a new location with a similar envi-
ronment, especially if associated species all move together so as to
preserve what we now call the ecosystem.
Darwin insists that all the species within a genus must have come
from a single progenitor. By the same token, scattered populations
of the same species must have been derived originally from a single
location - it is inconceivable that identical individuals could have
been derived from parents specifically distinct. Naturalists have long
discussed the question of "single centres of supposed creation," and
although there are many difficulties to explain on the hypothesis of
migration, the simplicity of the idea of production in a single region
"captivates the mind." 20 To reject this idea is to reject the vera causa
of ordinary generation and migration and to call in the agency of a
miracle. The observation that land animals are confined to territories
defined by ocean barriers while plants are not is explained by the
fact that the animals cannot cross those barriers, while there are
mechanisms by which plants can occasionally be transported across
stretches of open sea. Darwin admits that there are anomalies that at
first sight will seem difficult to explain, but he argues that they are
not sufficient to cause us to give up the idea of dispersal, especially
when we understand how complex are the processes that might play
an occasional role in transporting living things across barriers.
There follows an extensive description of the evidence Darwin
has now accumulated to show how many different mechanisms can
contribute to the process by which individuals may occasionally
cross what might have been thought to be impassable barriers. He
stresses that what appear as barriers now may not have been insu-
perable under earlier, quite different conditions. But he is now very
critical of Forbes and those naturalists who have "hypothetically
bridged over every ocean." 21 They have no authority, he insists,
for invoking such changes on this scale. There is no evidence that
the continents have been united in the recent past, and indeed the
20
Ibid., p. 352.
1 Ibid., p. 357.
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164 PETER J. BOWLER
absence of many mainland forms on oceanic islands counts against
this. Instead, he describes the many accidental (or better, occasional)
means of dispersal available to species. In particular, he recounts
his own and other naturalists' observations and experiments on how
seeds, eggs, and even small insects can be carried across the sea. In
some cases, seeds can still germinate after weeks of immersion in
seawater, while floating vegetation and icebergs can transport veg-
etation across long distances, provided the currents are favourable.
Insects can be carried for many miles out to sea on the wind, as can
birds - and the latter can carry all manner of seeds and even minute
land creatures in the mud attached to their feet.
Darwin now moves on to his theory of the dispersal of Arctic
plants during the glacial epoch, offering this as an alternative to the
theory of multiple creations to explain the disjunct populations of
alpine species. Far more than in 1844, though, he develops this idea
on a global scale to explain both the uniformity of Arctic plants in
the Northern Hemisphere and the occasional examples of Northern
Hemisphere plants that occur in isolated regions of the South. The
plants of Arctic Eurasia and America may have been able to mingle
during an earlier period having a warmer climate, when they lived
closer to the pole, where the land surface is more continuous. They
would then have migrated southward as the Earth cooled, reaching
their present, more scattered locations. The northern plants found in
the South may have been able to migrate across the equator during
such a period of cold, using high ground where the conditions were
cooler and drier, as a 'bridge'. At this point, Darwin assumes that
both hemispheres would have experienced cold conditions at the
same time.
Darwin argues that only the most successful northern species
would be hardy enough to make the crossing, and he discusses at
some length the question of why some northern forms have moved
into the Southern Hemisphere, while very few species have moved in
the opposite direction. The answer to this lies in the greater land sur-
face available in the North, which has stimulated competition and
diversity and led to the northern species being, in effect, more aggres-
sive. Darwin thus joins the long tradition of naturalists (Hooker
included) who invoked the metaphors of imperialism to describe the
migrations of animals and plants. Any southern forms that tried to
move northward would have "yielded to the more dominant forms,
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Geographical Distribution in the Origin 165
generated in the larger areas and more efficient workshops of the
north." 22 The chapter ends with another metaphor, borrowed from
Lyell, that compares the northern forms now stranded on mountains
around the globe to "savage races of man, driven up and surviving
in the mountain-fastnesses of almost every land, which serve as a
record, full of interest to us, of the former inhabitants of the sur-
rounding lowlands." 23
In the next chapter, Chapter 12 of the first edition, Darwin first
addresses the distribution of freshwater life, which often exhibits
surprising uniformity over large areas. This is due, he believes, to the
ease with which these organisms can migrate in a step-by-step fash-
ion, each individual move covering a short distance. Local changes
in the land surface are continually modifying the course of rivers,
allowing them to merge and then separate. Darwin gives further
details of experiments and observations on how seeds, eggs, and so
forth can be transported on the feet of wading birds and ducks.
The next topic is oceanic islands, and here, as in 1844, the
Galapagos Islands figure prominently. Islands remote from the main-
land characteristically lack certain kinds of animal, especially those
that would find it difficult to get transported accidentally across
the ocean. Amphibians, for instance, are always absent even though
there are conditions suitable for them - and amphibian adults and
eggs are killed by even a short immersion in salt water. As Darwin
says: "But why, on the theory of creation, they should not have been
created there, it would be very difficult to explain." 24 One charac-
teristic of remote islands (as opposed to those close to a mainland)
is the high proportion of endemic species, that is, of species that
are found there and nowhere else. Yet the species are always closely
related to those found on the nearest mainland. On the Galapagos,
for instance, "almost every product of the land and water bears the
unmistakeable stamp of the American continent." 25 Why should
this be so, on the theory of creation? The conditions on the island
are unlike any found on the mainland, yet the species show a close
22 Ibid., p. 380. On the use of imperialist metaphors in biogeography and related areas,
see Bowler (1996), Chapter 9.
23 Darwin (1859), p. 382.
24 Ibid., p. 392.
25 Ibid., p. 398.
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I 66 PETER J. BOWLER
relationship. The answer is, Darwin argues, that the island popu-
lations are established by occasional migration from the mainland,
but since continued restocking by mainland forms cannot occur, the
island populations have diverged and become distinct species.
The same argument can be applied to the differences between the
species on individual islands. Although physical conditions on the
islands are similar, new arrivals will not necessarily face the same
organic environment, since they may have been preceded by other
species that have already become established - and these will be dif-
ferent on each island because of the haphazard nature of the trans-
portation process. There will be no regular communication between
the island populations, because although they are not far apart, there
are strong currents in the local waters, and gales of wind are rare. So
each population evolves in isolation and becomes a distinct species,
which only rarely spreads to another island. 26
In conclusion, Darwin notes that wide-ranging genera have wide-
ranging species, which is what we would expect if speciation follows
dispersal to separate localities. The most wide-ranging (and hence
successful) species will have the best chance of being transported
elsewhere and establishing themselves in new locations. In general,
it is the most lowly organized forms that are the most widely dis-
tributed. This is because they are both more ancient, and hence have
had more time to spread, and less likely to change, thus preserving
ancestral relationships over long periods. All of the facts cited in this
and the preceding chapters "are, I think, utterly inexplicable on the
ordinary view of the independent creation of each species, but are
explicable on the view of colonisation from the nearest and read-
iest source, together with the subsequent modification and better
adaptation of the colonists to their new homes." 27
Darwin's purpose was the same in 1844, in 1856, and again in
1859. He was not trying to suggest that evolutionism should become
the basis for an attempt to reconstruct the whole history of life on
Earth. Indeed, he doubts that there is, or perhaps ever will be, enough
evidence to allow a detailed understanding of the ancestry and origi-
nal home of every major branch of the tree of life. His purpose in sur-
veying the fossil record and the geographical distribution of life is the
26 Ibid., pp. 401-3.
17 Ibid., p. 406.
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Geographical Distribution in the Origin 167
far more modest one of undermining the theory of special creation
and suggesting that his own theory provides a better understanding
of what we do know about the distribution of organisms in space and
time. In the case of geographical distribution, he selects a few case
studies where he can identify known patterns that make no sense
at all in terms of special creation, but that fit quite naturally into
his own system provided we make reasonable allowances for what
may have happened in the geological past and for our ignorance of
all the possible means of transportation. It is particularly important
for him to undermine the case for the multiple creation of species in
separate locations, and here the plausibility of the case for migration
at some past time is crucial. Darwin's argument is as much negative
as positive: it is an attack on the plausibility of the creation theory
coupled with the suggestion that - whatever the difficulties of some
individual cases - descent with modification provides a reasonable
explanation of the phenomena that are so damaging for the rival
theory.
The closest Darwin comes to anything like a global theory is
his use of the Ice Age to explain how northern plants could reach
various locations in the Southern Hemisphere. But although this
argument makes use of long-range geological and climatic changes
to suggest how migration routes could have opened up in the past,
its purpose is still restricted to providing an alternative to the theory
of multiple creations. Darwin is not trying to explain the origins of
the northern plants, except in the sense that he supposes northern
forms to be more vigorous than southern ones because of the more
active competition they will have faced. His target is merely another
case of disjunct distribution that might otherwise give comfort to
the creationists. He is not trying to lay the foundations for a complete
phylogeny of the plant kingdom.
V. LATER DEVELOPMENTS
The two chapters on geographical distribution underwent minor
modifications in later editions of the Origin, but remained essen-
tially the same in terms of their main arguments (they become Chap-
ters 1 1 and 1 3 in the sixth edition following the insertion of the new
Chapter 7 on further objections to the theory). Most of the minor
changes involve the addition of new information on the locations of
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I 68 PETER J. BOWLER
species and the various means of transportation postulated. Darwin
continued to argue with Hooker, who published an important paper
on the distribution of Arctic plants in 1861. 28
The only major change to Darwin's arguments came in the fifth
edition of 1869, where he revised his explanation of how northern
plants might have crossed the equator to colonize locations in the
Southern Hemisphere. This followed his acceptance of James Croll's
theory of Ice Age causation, which entailed a reconsideration of
the assumption that the colder conditions had affected both hemi-
spheres at the same time. In a paper published in 1864, and later in
his book Climate and Time, Croll developed an astronomical expla-
nation of the Ice Ages based on variations in the amount of the sun's
heat reaching the Earth's surface. 29 Because this theory depended on
changes in the inclination of the Earth's axis of rotation, it required
that the cooling of one hemisphere should coincide with a warmer
climate in the other. If the theory were accepted - and it was certainly
seen as a promising initiative - Darwin's original assumption that
the cooling would have affected the whole globe would have to be
abandoned. It is clear from Darwin's letters to Croll, however, that
he was far from happy with his original explanation of how northern
plants could have crossed the equator at a time of general cooling.
He would be much happier with an explanation based on cooling in
only one hemisphere - indeed, he told Croll, "it would have been
an immense relief to my mind if I could have assumed that this
had been the case." He subsequently wrote that Croll's results were
"of more use to me than, I think, any other set of papers which I
remember" and suggested that the facts of distribution were strong
evidence in favour of his theory. 30
In his fifth edition, Darwin introduced a brief description of Croll's
theory and then considered its implications for his own views. He
now argued that during an Ice Age in the North, some of the most
vigorous temperate species would have been able to gain a foothold
28 Hooker (1861); see Darwin to Hooker, February 25, 1862, in Correspondence, 10:
93-5-
29 Croll (1864, 1875); for details, see David Oldroyd (1996), pp. 15 1-4, and Bowler
(1992), pp. 227-30.
30 Darwin to Croll, November 24, 1868, and January 31, 1869, in Letters, 2: 161-
5. More letters between Darwin and Croll are now being edited by the Darwin
correspondence project.
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Geographical Distribution in the Origin 169
in equatorial regions and would have been able to cross the equa-
tor, because the southern tropical forms would have moved south
owing to the warmer conditions there. When the glacial period was
ended in the North, the northern forms would move back to more
northerly latitudes, but might leave remnant populations isolated
in mountainous regions of the southern equatorial lands they had
temporarily invaded. When the Southern Hemisphere experienced a
glacial period in its turn, these isolated forms would have been able
to spread out across that hemisphere to reach the scattered locations
in the far South where they survive to the present. The disturbances
would have produced major extinctions in the original equatorial
flora. 31
The new explanation of how northern plants were able to move
to isolated regions of the South was perhaps more complex than
the original one. The fact that Darwin was prepared to make these
additions shows how seriously he took the whole issue of geologi-
cal climates and how vulnerable he felt to challenges on that score.
Croll's theory allowed him to construct what he felt was a more
plausible account of how plants could cross the barrier of the equa-
tor. Darwin's modified explanation retained the essential logic of his
argument - that is, that there was a viable alternative to multiple
creations - even though the new version was somewhat more com-
plex than the old. In a sense, though, Darwin's position may have
been strengthened by the uncertainty surrounding the question of
the Ice Ages, since this reinforced his view that we simply cannot
be sure about the climatic changes that may have opened up migra-
tion routes in the distant past. In these circumstances nothing could
be ruled out, and the creationist position that there was no viable
natural explanation of these disjunct populations was untenable.
VI. WALLACE AND THE GEOGRAPHICAL DISTRIBUTION
OF ANIMALS
Darwin's very cautious approach to the evidence from paleontol-
ogy and biogeography focussed on individual case studies where
he felt he could either make a positive case for common descent
31 In Variorum, the main additions are Chapter n, sentences 215. 1-9, 245.1-11,
246.1-5, and 248.1.
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170 PETER J. BOWLER
or undermine the credibility of the creation theory. His restraint
contrasts with the increasing boldness of evolutionists in the later
decades of the nineteenth century. Ernst Haeckel and others appealed
to morphological evidence from comparative anatomy and embryol-
ogy to fill in the gaps in the fossil record and allow the reconstruc-
tion of phylogenies for all the main groups of animals and plants.
Far from restricting themselves to individual case studies, this later
generation of evolutionists wanted to reconstruct the whole history
of life on Earth. Biogeography would play an important role in this
project, since it was hoped that the evidence from past and present
distributions would allow evolutionists to identify the location in
which each major group had evolved, and to trace its subsequent
migrations.
Haeckel himself appealed to geographical evidence in his History
of Creation to make the case for the monophyletic origin of every
major new type. This would remain a significant issue, the alterna-
tive being not multiple creations but the anti-Darwinian theories of
parallel evolution that would allow the same type to evolve sepa-
rately from distinct ancestral forms. 32 But the comprehensive incor-
poration of geographical factors into the search for life's ancestry was
inspired to a large extent by the work of Alfred Russel Wallace. His
efforts in this area have been overshadowed by his role in the discov-
ery and original publication of the selection theory, but his monu-
mental Geographical Distribution of Animals of 1876 provided the
first really comprehensive account of zoological biogeography and
ushered in a period of intense activity among naturalists eager to
identify the actual locations of the major steps in evolution and the
subsequent expansions and extinctions of the major animal groups.
Wallace at first shared Darwin's fears that the available evidence
was simply not enough to allow a comprehensive reconstruction of
the history of life. He had been led to the idea of evolution in part by
his own biogeographical studies, and he continued to work on the
zoogeography of the Malay Archipelago in the early 1860s. In the
Preface to his 1876 book, he records that he had then been asked by
Darwin and by Alfred Newton, the Cambridge professor of zoology,
to undertake a global survey of zoogeography. He had abandoned the
32 Haeckel (1876), vol. 1, Chapter 14.; and Bowler (1996), Chapter 8.
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Geographical Distribution in the Origin 171
project in despair at the lack of information on many groups, but
was revitalized by the publication of a number of detailed surveys
and launched once again into the effort to produce a comprehensive
overview. 33
The result was, in effect, an extension of the Darwinian project
on a global scale, far beyond anything Darwin himself had consid-
ered possible. Wallace shared Darwin's distrust of claims about land
bridges' in the recent past and was convinced that the zoological
provinces he had identified were defined by ocean barriers that had
been permanent at least through the Tertiary era. He shared Dar-
win's view that geological changes produced their effect on life not
by altering the world's geography, but by modifying the climate in a
way that forced species to migrate and both opened and closed the
routes available to them. From the information he reported on the
distribution of the living and fossil members of each group, he was
able to generate hypotheses about the original home in which the
first members of each group had evolved and to suggest the time
and routes of subequent migrations. The existing state of each zoo-
logical province was, in effect, a composite built up as a result of
successive migrations and extinctions. Wallace endorsed Darwin's
idea that most of the successful groups had appeared first in the
North, but he was able to suggest how and when they had moved to
take up their present distribution.
In his later book Island Life, Wallace contributed to Darwin's
most important case study, the population of oceanic islands. He also
examined the question of changing geological climates and proposed
a modification of Croll's theory of the Ice Ages. 34 His work seems
to have triggered an explosion of interest in evolutionary biogeog-
raphy that fed into the late nineteenth century's fascination with
the effort to reconstruct the history of life on Earth. Rival theories
were proposed, the supporters of the Darwin- Wallace position on the
permanence of continents vying with those who preferred Hooker's
hypothetical extensions of the land surface. In the early twentieth
century the whole phylogenetic project came under a cloud, as a new
generation of biologists became suspicious of the speculative nature
33 Wallace (1876), vol. 1, pp. v-vi.
34 Wallace 1880).
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172, PETER J. BOWLER
of the theories that had been proposed. Perhaps Darwin was wise to
limit his attention to a small number of well-defined topics within
the field, although we can hardly blame Wallace for hoping that the
explosion of information that was becoming available in the 1870s
might be enough to resolve the issues.
Cambridge Collections Online © Cambridge University Press, 2009
RICHARD A. RICHARDS
10 Classification in Darwin's
Origin
I. A PUZZLE
Textbook histories tell us that Charles Darwin sparked a scientific
revolution with the publication of his Origin of Species in 1859.
While this revolution is obvious in many biological disciplines, it
is less so in biological taxonomy or systematics - the grouping and
classification of organisms. After all, the approach most of us learn
in school today was first developed by Linnaeus in 1735 - 124 years
before the Origin. That being the case, where is the revolution? Sys-
tematist Ernst Mayr expresses this doubt: "As far as the methodol-
ogy of classification is concerned, the Darwinian revolution had only
minor impact" (Mayr 1982, 213). Mayr is right in that the Linnaean
hierarchy predated but also survived the Darwinian revolution, and
has remained in use today. But it would be wrong to conclude that
the Darwinian revolution was irrelevant to classification.
My intention here is to sketch out Darwin's influence on classi-
fication and the role classification played in his larger project. We
shall see that despite the superficial similarity between pre- and
post-Darwinian classification, Darwin's influence has nonetheless
been profound. He gave systematics a theoretical foundation and
an operational method. Moreover, classification was important to
Darwin's project. His discussion of it in the Origin comes at the
end, unifying and drawing together threads from important topics
in earlier chapters - natural selection and divergence, comparative
anatomy and morphology, and embryology and development. To
The suggestions of the editors, Robert Richards and Michael Ruse, have been very
helpful. The views presented here are my own.
173
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174 RICHARD A. RICHARDS
make all this clear, I will begin with a brief summary of the classifi-
catory approaches predating the Origin (section II). Following that, I
explain Darwin's views on classification in the Origin (section III);
and finally, I will briefly describe how his views have endured in
more recent approaches (section IV).
II. CLASSIFICATION BEFORE THE ORIGIN
Histories of classification usually begin with Aristotle. But this is
somewhat misleading. While Aristotle spent great effort in observing
and recording the features of animals that might have functioned
in a grand classification, his methods and goals were not those of
more modern systematists. He is well known for using the standard
classificatory terms genus and species to divide and differentiate
groups of organisms, but he used these terms in a variety of ways,
and at a variety of levels, generally relative to the investigation at
hand. Genus and species were not the fixed taxonomic levels for
Aristotle that they would become for modern systematists (Grene
and Depew, 18).
Furthermore, modern systematists observe the pattern of similar-
ities and differences in organisms in order to group them into taxa.
Feathers and beak shape, for instance, are used to group organisms
into bird genera and species. But Aristotle was more interested in
classifying the character traits of the organisms than the organisms
themselves. He focused on traits because his goal was the discovery
of the explanatory principles that governed their functioning. In his
History of Animals, he gave descriptions of the various functional
parts of various kinds of animals. Then, in the Parts of Animals, he
provided causal explanations in terms of the functioning of the parts.
He noted, for instance, the correlation of lungs, windpipe, and esoph-
agus in various groups, and how this could be explained in terms of
functioning. When he did bring the groupings of organisms into the
discussion, it was typically subservient to his theorizing about reg-
ularities in the distribution of character traits (Lennox, 14-20).
Those who followed Aristotle turned toward the goal of a grand,
overarching classification of organisms, based upon a term used by
Aristotle, scala naturae, as the foundation for a classificatory system
conceived as a "ladder of nature" or "great chain of being." With the
help of the physician Galen, who saw each link of the chain as
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Classification in Darwin's Origin 175
existing for the purposes of higher-level links, thinkers through to
the Renaissance apparently had little difficulty in giving this idea a
theological gloss, seeing the "great chain of being" as representing
degrees of perfection and leading to humans and beyond - ultimately
to God (Grene and Depew, 14-33).
With the Renaissance emphasis on observation, and the discovery
of many new plants and animals, it became increasingly clear that
no simple, linear scala naturae was sufficient to represent organic
diversity. Credit goes to botanists such as Cesalpino (15 19-1603)
and to zoologists such as Pierre Belon (15 17-15 64), who classified
birds; Guillaume Rondelet (1507-15 66), who classified fish, crus-
taceans, mollusks, and sponges (and several sea monsters as well);
and John Ray (1 627-1 705), who not only identified thousands of
plant species, but also produced synoptic volumes on reptiles in
1693, on insects in 1705, and on birds and fishes (posthumously) in
1 71 3 (Mayr 1982, 160-9). From the sixteenth to the eighteenth cen-
tury, there was an explosion of information about organic nature,
but with no established procedure for describing, naming, and clas-
sifying species. Circumstances were ripe for the most famous of sys-
tematists, the Swedish botanist Carl von Linne (1 707-1 778), known
better by the Latinized "Carolus Linnaeus."
In 1735, Linnaeus was studying medicine in the Netherlands
when he published his Systema Naturae Sive Regna Tria Natu-
rae Systematice Proposita per Classes, Or dines, Genera &) Species.
While this first edition consisted of only a title page, eleven pages
of "observations" and taxonomic tables, and two one-page leaflets,
later editions expanded dramatically. The thirteenth edition of 1770
was over 3,000 pages, classifying many thousands of plant and ani-
mal species. In these thirteen editions of his Systema Naturae,
Linnaeus worked out first, a nesting, hierarchical approach to clas-
sification that consisted of three kingdoms - animal, plant, and
mineral - each subdivided into orders, classes, genera, and species;
and second, a system of binomial nomenclature that identified
each species on the basis of the now familiar genus-species name.
Humans, for instance, were named Homo sapiens, and classified
in the order "Anthropomorpha," along with the other primates in
Simia.
The significance of Linnaeus comes not from his classifications,
but from his streamlined descriptions, standardized terminology,
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176 RICHARD A. RICHARDS
and classificatory framework that is relatively unambiguous, uni-
form, and easy to apply (Mayr 1982, 173). The Linnaean framework
was eventually adopted by Darwin, survived the Darwinian revolu-
tion, and is still widely used today, but with the addition of multiple
taxonomic categories, from subspecies to subphylum, superclass,
subclass, infraclass, cohort, suborder, infraorder, superfamily, fam-
ily, subfamily, tribe, subtribe, and more (Ereshefsky, 215).
In the early 1800s, however, the Linnaean system was not the
only system. In his 181 7 Regne Animal, Georges Cuvier argued for
a system of classification based on four "embranchements" - ver-
tebrata, mollusca, articulata, and radiata. Each embranchement was
subdivided into smaller Linnaean units - class, order, family, genus,
subgenus, and species. These embranchments were based on the idea
that there were four basic general body plans in nature, each associ-
ated with a particular kind of nervous system. While there was vari-
ability within each embranchment on the basis of differences in the
conditions of existence to which each organism was adapted, there
were unbridgeable gaps between the plans (GreneandDepew, 143-5).
By 1 82 1, William S. MacLeay had developed a "quinarian" system
whereby animals and plants were each arranged into a grand cir-
cle of five principal forms. In the animal circle there were five
classes - Acrita, Radiata, Annulosa, Vertebrata, and Mollusca. Each
of these five classes contained five orders, each of which contained
five tribes, continuing on down in smaller nested groupings of five.
Vertebrata, for instance, contained fish, amphibians, reptiles, birds,
and mammals - each subdivided into five smaller groups. Quinarian-
ism was taken seriously, especially in England. The Zoological Club
of the Linnaean Society, for instance, spent much time debating and
discussing it between 1825 and 1830. By the mid-i840S, however,
many British naturalists (including Darwin) were coming to reject
MacLeay's system (Ospovat, 101-13; Hull 93-6).
In the various debates about classification preceding the publica-
tion of the Origin, there were two recurring questions: first, what
made a classification "natural," second, what characters should a
classification be based upon? The first question was about theo-
retical basis: what was the classification supposed to represent or
express? Most systematists from the Middle Ages up until the pub-
lication of Darwin's Origin gave a theological answer to the theo-
retical question: a "natural" classification was one that expresses
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Classification in Darwin's Origin 177
God's plan; and by studying nature, the systematist was studying
God's plan. Linnaeus was of this view, seeing himself as a sort of
prophet, chosen by God to reveal the deepest and most profound
laws decreed in the creation (Lindroth, 13). Similarly, MacLeay was
committed to a theological basis for classification. The quinarian
system was "natural," according to MacLeay, because it expressed
the plan of God in creation, and its mathematical beauty (based on
the number five) revealed the rational design that God had imparted
(Ospovat, 106). For both Linnaeus and MacLeay, because God was
rational, there was a rational order to nature that could be uncovered
through careful observation and reason.
It should be apparent that this theological basis for classification
presents problems. First, unless we already know something about
God's plan in the creation, it is unclear how we can tell we have
it right. The fact that God is rational and would have expressed his
design in a rational way is of little help - unless we can evaluate
systems based upon their rationality. But it is hard to see how to
do this. Are Linnaeus's three kingdoms more rational than Cuvier's
four embranchments or MacLeay 's quinarianism? The only real stan-
dards that systematists had were operational: the ability to construct
a classification that was unambiguous and complete, in which every
form of life has its place and only one place. But the mere ability to
do this is insufficient. Suppose we could, for instance, classify unam-
biguously on the basis of color. It is unlikely that any systematist
would regard color as a satisfactory grouping principle except as it
met some merely practical need. Or perhaps, as Linnaeus argued, a
natural system is one based on all characters of the organism, since
each character is ultimately an expression of God's design. Believing
this to be an impossible goal, however, Linnaeus used only some
characters, mostly sexual, especially in his botanical groupings.
Others followed Linnaeus in using a special similarity approach.
MacLeay based his quinarian system on a distinction already in
use between "affinities" and "analogies." An affinity, according to
MacLeay, is a shared character or similarity that is correlated with
other similarities and can be seen to form an uninterrupted series. An
analogy is a similarity that is not correlated with other similarities
and does not form an uninterrupted series. For MacLeay, grouping
should be based primarily on affinities, although analogies must also
be represented in the groupings. In other words, an organism might
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178 RICHARD A. RICHARDS
be placed in Vertebrata on the basis of affinity - a series of correlated
characters - but it may well have parallel similarities - analogies -
with other groups (Ospovat, 104-6).
This affinity/analogy distinction led to the more familiar homol-
ogy/analogy distinction. Richard Owen, who was influenced early on
by MacLeay (Ospovat, 107), worked out this distinction in response
to a disagreement between Georges Cuvier and Etienne Geoffroy
Saint-Hilaire. Cuvier and Geoffroy were comparative anatomists at
the Museum National d'Histoire Naturelle in Paris who engaged in
a famous debate in 1830 about the laws of anatomy. It was standard
at this time to see Newton as presenting a model for all sciences,
based on the search for universal laws. Cuvier, in particular, sought
a Newtonian basis, asking: "Why should not natural history also
have its Newton some day?" (Grene and Depew, 134) But Cuvier
and Geoffroy disagreed about the nature of these universal laws gov-
erning anatomy.
Cuvier adopted what has traditionally been described as a teleo-
logical or functional approach: the laws of anatomy are those that
govern the functioning of parts in individual organisms so that the
organism can function well relative to its conditions of existence.
Cuvier explained:
Natural history, however, also has a rational principle which is peculiar to it
and which it uses to advantage on many occasions,- it is that of the conditions
of existence, commonly called final causes. As nothing can exist unless it
combines in itself the conditions which make its existence possible, the
different parts of each being must be coordinated in such a way as to make
possible the total being, not only in itself, but in its relations with those
which surround it; and the analysis of these conditions often leads to general
laws as demonstrable as those which derive from calculation or experiment.
(Ospovat, 8)
For Cuvier, the laws governing anatomy relate to the functioning
of the whole individual on the basis of the relation of its parts, and
the relation of the organism to its environment (Ruse 1999, 12-13).
Geoffroy, on the other hand, focused more on the extensive patterns
of similarity among organisms. He thought the laws of anatomy
should be understood as relating the similarities or "unities of plan"
among groups, irrespective of functioning (Grene and Depew, 138).
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Classification in Darwin's Origin 179
While Cuvier and Geoffroy understood their views to be incom-
patible, Richard Owen did not. He focused on Geoffory's unities of
plan, described them as archetypes, and tried to place them within
Cuvier's classificatory system, arguing that they underlay the func-
tional structures of the four embranchments (Grene and Depew,
1 80-1 ). In doing this, Owen was trying to incorporate both insights -
the Cuvierian insight into function and the Geoffroyian insight into
structural similarities. Owen used the terms "analogue" for the
characters that had similar functions but different structures, and
"homologue" for the characters that had similar structures with-
out necessarily functioning in similar ways (Ruse 1999, 1 16-124).
According to Owen, this implied that we could study organisms from
two distinct but by no means incompatible points of view - to ascertain first
to what it may be analogous &. secondly with what it may be homologous -
to study the skeleton teleologically and morphologically. (Ospovat, 130)
We can, for instance, look at the forelimbs of humans and the wings
of birds morphologically, and see that they exhibit a similar cor-
respondence of parts - both relative to parts of the limb itself and
relative to the rest of the organism. Or we can look at them teleo-
logically, and see that they function in different ways - as adapted
to different ends.
Despite Owen's distinction between homologies and analogies,
it should be obvious that there were still very difficult problems
confronting systematists in the first half of the nineteenth century:
first, there was still no satisfactory account of how one could tell
when a classification was "natural" - expressing God's plan; second,
the recognition that some similarities were based on function and
some on form was not sufficient to indicate how to construct a
natural classification. Did God's plan require a classification based
on homologies - Geoffroy's unity of plan - or did it require one
based on analogies - Cuvier's functional adaptation to conditions of
existence? Or should one employ both homologies and analogies?
The lack of satisfactory answers to these questions might encour-
age us to agree with Georges Buffon, Linnaeus's critic and contempo-
rary, who believed that the only real biological taxa were species. For
Buffon, species groupings were based on real processes in nature -
reproduction and genealogical relationships. Higher-level groupings
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180 RICHARD A. RICHARDS
into the Linnaean categories, genera, classes, orders, kingdoms, and
so on were based on mere abstract relations, which were not just
a waste of time and effort, but antithetical to the study of nature.
To truly study nature, one had to study real processes and relations
(Grene and Depew, 74; Mayr 1982, 180-2).
From a modern perspective the problems in pre-Darwinian classi-
fication are evident. First, there is no way to tell when a classification
has met its theoretical goal - representing God's design in the cre-
ation. Consequently, preference for one or the other system seems
arbitrary. There is no obvious reason to prefer Linnaeus's system
with its three kingdoms, Cuvier's system with its four embranch-
ments, or Macleay's system with its two sets of five circles of affinity.
Second, and as a consequence of the first problem, there is no way to
tell which operational procedures satisfy the theoretical goal. Which
similarities should we focus on in grouping organisms to represent
God's plan?
III. CLASSIFICATION IN THE ORIGIN
Darwin began working out his views on evolution in 1837 with the
first of his transmutation notebooks. At the time, he took seriously
the various classificatory approaches in circulation. In his early writ-
ings, he seemed to have just assumed that MacLeay's quinarian clas-
sification was largely correct, and that it therefore required an evo-
lutionary explanation (Ospovat, 108). But by the mid-i840S, when
most naturalists in Great Britain were coming to reject McLeay's
system, Darwin no longer needed to take quinarianism seriously.
Darwin had long been aware of Cuvier's views on a variety of
topics, including classification, but he did not turn to a Cuvierian
system after rejecting MacLeay's. This should come as no surprise.
From his first transmutation notebook in 1837, Darwin had begun
to think about classification in terms of genealogy. Six years later
he was explicitly advocating genealogy as a theoretical principle in
a series of letters to the zoologist G. R. Waterhouse [Correspon-
dence, 2: 375-6). And fourteen years after that, Darwin disagreed
with his friend and advocate T H. Huxley, who was still favoring
Cuvier's nongenealogical classification [Correspondence, 6: 461-3).
For Darwin, if classification were to be based on genealogy, then only
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Classification in Darwin's Origin 181
those similarities that were indicative of genealogy should be used
in grouping organisms. This general framework - with its theoretical
basis and operational method - demanded answers to two questions:
What sort of a classificatory system best reflected genealogy? What
kinds of similarities or shared characters were indicative of geneal-
ogy? These questions were answered in the Origin of Species.
In the first edition of the Origin, Darwin devoted much of the
penultimate Chapter 13 to classification. He began the chapter with
a statement of the basic premise of classification - that there are
patterns of similarity among organisms and that these patterns can
be used to group organisms. Then Darwin tells us why this grouping
is not arbitrary: it is based on the tree-like branching of evolution.
To make his case, he returned to threads from previous chapters on
"Variation" and "Natural Selection," where he developed the rea-
soning behind his "Principle of Divergence." The basic idea is that
any particular geographic area can support more life if organisms
diversify and vary in their habits of life by diverging from the ances-
tral form. Intermediate forms will tend to be eliminated because
they will be competing with both sets of divergent forms, while the
most divergent forms will have the least competition. A form that
is intermediate in size, for instance, will probably be in competition
with both its larger and smaller cousins in terms of food and shelter,
while the largest and smallest forms will be in competition only
with the intermediate form. This divergence, Darwin claims, leads
to a branching process in evolution. He refers to a tree figure (fron-
tispiece, p. ii) that appeared in the chapter on "Natural Selection"
(the only illustration in the first edition of the Origin).
I request the reader turn to the diagram illustrating the action, as formerly
explained, of these several principles; and he will see that the inevitable
result is that the modified descendants proceeding from one progenitor
become broken up into groups subordinate to groups. [Origin, 412)
Darwin summarizes how this branching produces a group-in-
group classification:
So that we here have many species descended from a single progenitor
grouped into genera,- and the genera are included in, or subordinate to, sub-
families, families and orders, all united into one class. [Origin, 413)
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I 82 RICHARD A. RICHARDS
What is important in this tree figure, and the accompanying text, is
that genealogy and the grouping of species into higher categories -
genera, families, orders, and classes - are to be understood in terms
of this branching of the tree.
But this does not, by itself, give us a classification. Does a partic-
ular branch represent a genus, a family, an order, or a class? This is
the "ranking" problem: at what level in the classificatory hierarchy
do we place each group? According to Darwin, we should rank on
the basis of degree of modification:
I believe that the arrangement of the groups within each class, in due sub-
ordination and relation to the other groups, must be strictly genealogical in
order to be natural; but that the amount of difference in the several branches
or groups, though allied in the same degree in blood to their common pro-
genitor, may differ greatly, being due to the different degrees of modification
which they have undergone,- and this is expressed by the forms being ranked
under different genera, families, sections, or orders. [Origin, 420)
Implicit in this idea that classification should be based on the
branching of the evolutionary tree is Darwin's theoretical basis -
the purpose and goal of classification is to represent genealogy. And
because genealogy is ultimately the product of heredity, branching,
and divergence, the genealogical system will be hierarchical, with
organisms placed in groups representing the branches of the evolu-
tionary tree. For Darwin, this is what makes it a "natural" system.
It is worth noting here, however, that Darwin did not believe that
he was proposing an entirely new approach to classification. First,
because we already group together males and females of a species,
as well as organisms at different stages of development - no matter
how different they may be in form - we are using a genealogical
classification.
With species in a state of nature, every naturalist has in fact brought descent
into his classification,- for he includes in his lowest grade, or that of a species,
the two sexes,- and how enormously these sometimes differ in the most
important characters, is known to every naturalist: scarcely a single fact
can be predicated in common of the males and hermaphrodites of certain
cirripedes, when adult, and yet no one dreams of separating them. The nat-
uralist includes as one species the several larval stages of the same individ-
ual, however much they may differ from each other and from the adult. . . .
[Origin, 424)
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Classification in Darwin's Origin 183
Second, Darwin believed that we already classify genealogically
those organisms whose genealogies we know - domestic varieties.
In confirmation of this view, let us glance at the classification of varieties,
which are believed or know to have descended from one species. These
are grouped under species, with sub-varieties under varieties,- and with our
domestic productions, several other grades of difference are requisite, as we
have seen with pigeons. The origin of the existence of groups subordinate
to groups, is the same with varieties as with species, namely, closeness of
descent with various degrees of modification. Nearly the same rules are
followed in classifying varieties, as with species. [Origin, 423)
Third, Darwin believed that some classifications of species had been
genealogical all along, because some systematists had inadvertently
used characters that indicated ancestry. When Linnaeus grouped
organisms on the basis of similarities in their sexual organs, and
when MacLeay used "affinities," both were unwittingly using char-
acters that Darwin thought were good indicators of genealogy. This
last point can be seen in Darwin's operational method.
One of the chief advantages of Darwin's approach to classifica-
tion over those of Linnaeus, Cuvier, and MacLeay is that its the-
oretical basis provided the foundation for an operational method.
Because classification is based on natural processes - the branching
and divergence of evolution - we can use what we know about these
processes to group organisms. Darwin does this through a reinter-
pretation of distinctions used by MacLeay and Owen. Macleay had
argued that classifications should be generated on the basis of "affini-
ties" - the series of correlated similarities - rather than analogies -
isolated, noncorrelated similarities. And Owen had distinguished
structural similarities - "homologies" - from functional similari-
ties - "analogies." Darwin reinterpreted MacLeay's "affinities" and
Owen's "homologies" to be the similarities due to common ances-
try. The idea is that some characters common to different species are
due to common ancestry - inherited from a common ancestor. Other
characters are due to an adaptive response to the environment. If we
can tell which characters indicate genealogy or common ancestry,
we can group on the basis of them, rather than on those that are the
products of an adaptive response.
Based on this idea, Darwin gave us one general rule and a
set of corollaries for distinguishing homologies and analogies. He
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I 84 RICHARD A. RICHARDS
introduced the general rule by rejecting the view that characters
important to habits of life are relevant to classification:
It might have been thought (and was in ancient times thought) that those
parts of the structure which determined the habits of life, and the gen-
eral place of each being in the economy of nature, would be of very high
importance in classification. Nothing can be more false. No one regards the
external similarity of a mouse to a shrew, of a dugong to a whale, of a whale
to a fish, as of any importance. These resemblances, though so intimately
connected with the whole life of the being, are ranked as merely "adaptive
or analogical characters." . . . [Origin, 414)
The idea lurking here is that if a character has functional significance
for specific habits of life, it is likely to have been the more immediate
product of natural selection, and is thus irrelevant to classification.
We might express this rule as follows:
General Adaptation Rule: A shared character trait that is likely to
be an adaptation to a particular form of life is not likely to be homol-
ogous and is therefore irrelevant to classification.
Darwin followed this with a corollary:
It may even be given as a general rule, that the less any part of the organi-
zation is concerned with special habits, the more important it becomes for
classification. [Origin, 414)
According to the "special habits" corollary, the more traits or char-
acters are associated with special habits of life such as flying, swim-
ming, digging, and so on, the more likely they are to be recent prod-
ucts of adaptation rather than of common ancestry. A second, related
corollary was that reproductive organs are more useful in classifica-
tion. Darwin quoted Owen on this matter:
As an instance: Owen, in speaking of the Dugong, says "The generative
organs being those which are most remotely related to the habits and food
of an animal, I have always regarded as affording very clear indication of its
true affinities." [Origin, 414)
The basic idea of this reproductive organs corollary is that since
organs of generation are usually not associated with special habits of
life and the associated requirements of survival, they are unlikely to
be special adaptations, and are therefore relevant to classification.
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Classification in Darwin's Origin 185
Another corollary is related to the constancy of characters. Dar-
win suggested that systematists have often been using this principle
correctly:
If they find a character nearly uniform, and common to a great number of
forms, and not common to others, they use it as one of high value,- if common
to some lesser number, they use it as of a subordinate value. {Origin, 418)
The idea behind the constancy corollary is that characters that are
constant across species may be of importance to the species in
which they are found, but not as adaptations to local circumstances.
The similar skeletal structures of birds, dugongs, and humans, for
instance, are not likely to be adaptive responses to special condi-
tions, because birds, dugongs, and humans occupy very different
conditions of life.
Two more corollaries of great importance to Darwin were related
to rudimentary organs and embryological characters. Rudimentary
organs are those that appear to be atrophied instances of functional
characters. They are significant because in the rudimentary form
they are of little functional importance.
No one will say that rudimentary or atrophied organs are of high physiolog-
ical or vital importance,- yet, undoubtedly, organs in this condition are often
of high value in classification. No one will dispute that the rudimentary
teeth in the upper jaws of young ruminants, and certain rudimentary bones
of the leg, are highly serviceable in exhibiting the close affinity between
Ruminants and Pachyderms. . . . {Origin, 416)
Darwin thought rudimentary organs were important enough that
he devoted an entire section to them at the end of his chapter on
classification. He concluded this section:
As the presence of rudimentary organs is thus due to the tendency in every
part of the organization, which has long existed, to be inherited - we can
understand, on the genealogical view of classification, how it is that system-
atists have found rudimentary parts as useful as, or even sometimes more
useful than, parts of high physiological importance. Rudimentary organs
may be compared with the letters in a word, still retained in the spelling,
but become useless in pronunciation, but which serve as a clue in seeking
for its derivation. . . . {Origin, 455)
Darwin similarly devoted an entire section to embryological char-
acters. Like rudimentary organs, they are significant because it is
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I 86 RICHARD A. RICHARDS
unlikely that they are adaptations to local conditions. And the ear-
lier the characters appear in development, the less likely they are
to be adaptive responses. An embryo in a womb or an egg is, after
all, typically not subjected to the selection pressures of a particular
environment.
The points of structure, in which the embryos of widely different animals
of the same class resemble each other, often have no direct relation to
their conditions of existence. We cannot for instance, suppose that in the
embryos of the vertebrata the peculiar loop-like course of the arteries near
the branchial slits are related to similar conditions, - in the young mammal
which is nourished in the womb of its mother, in the egg of the bird which
is hatched in a nest, and in the spawn of a frog under water. [Origin, 440)
A grouping based on embryological characters, then, is more likely to
reflect genealogy, because these kinds of similarities are more likely
to be homologous - due to common ancestry - and less likely to be
analogous - due to the proximate operation of natural selection.
It is likely that Darwin worked out many of these principles dur-
ing his eight-year-long study of Cirripedes or barnacles - sea crea-
tures that cement themselves to surfaces, grow hard shells, and catch
food with feathery appendages. Darwin began studying barnacles in
1 846, at least in part because he was worried that he lacked sufficient
scientific authority for his theory of evolution to be taken seriously.
One way to get this authority was by the careful and detailed study
of a single group of organisms. In this he was successful, receiving a
Royal Society medal for his barnacle work in 1854 (Stott, xx-xxv).
The study of barnacles was significant for Darwin first, because it
revealed the great variability in nature. Darwin had earlier assumed
that there was relatively little variation within a species in nature -
except as a response to changes in conditions of existence (Ospo-
vat 78-9). But his careful study of barnacles revealed great variabil-
ity, even under similar conditions of existence. This was important
because it provided support for the principle of divergence and its
implied branching that Darwin used to introduce his chapter on clas-
sification. Constant variability throughout nature implies a constant
tendency for the divergence and branching of the evolutionary tree
that was the basis for Darwin's genealogical classification.
But his study of barnacles was also important for the develop-
ment of his operational method. Barnacles had been classified with
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Classification in Darwin's Origin 187
mollusks by Linnaeus, Cuvier, and Owen on the basis of the hard
shells in adults. But they are more similar to crustaceans such as
shrimp at the earliest stages of development. In confronting his hun-
dreds of specimens, Darwin had to decide which similarities were
most important to classification, both of the group as a whole and of
groups within the group. He concluded that the embryological sim-
ilarities to crustaceans implied that barnacles were really related
to crustaceans. But in dividing barnacles into smaller groups he had
great difficulty in settling on a satisfactory classification (Ruse 1999,
186; Stott, 53). The particulars of his eight-year project are less impor-
tant here than the fact that it was probably his detailed observation
and recording of all the glorious nuances of barnacle anatomy that
led Darwin into thinking about and developing his operational prin-
ciples as outlined earlier (Ghiselin, 103-30).
In the introductory section to this chapter, I suggested that clas-
sification came at the end of the Origin in part because of its impor-
tance in terms of unification. I cannot explain this idea adequately
here, but we can see what it involves. First, in order to group organ-
isms Darwin relied on assumptions about evolutionary processes.
He did this through the general adaptation rule and all its corol-
laries, embryology, rudimentary organs, constancy, and so on, that
were intended to distinguish homologies from analogies. In effect,
Darwin was not grouping just on the basis of observable similarities,
but also on the basis of a series of auxiliary theories he had about the
processes that cause and explain change, natural selection in partic-
ular. A natural classification for Darwin was to be constructed at
least in part on the basis of an explanatory framework.
But once a genealogical classification was constructed, it could in
turn serve an explanatory role:
All the great facts of morphology become intelligible, - whether we look to
the same pattern displayed in the homologous organs, to whatever purpose
applied, of the different species of a class; or to the homologous parts con-
structed on the same pattern in each individual animal and plant. [Origin,
45 6-7)
The idea here is that once we have a genealogical classification based
on the branching of the evolutionary tree, we can explain all the mor-
phological facts that had seemed to be unconnected and inexplicable
otherwise: facts about how mollusks and barnacles are similar in
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I 88 RICHARD A. RICHARDS
some ways and different in others; facts about how the forelimbs of
dugongs, moles, and bats have similar structures yet serve different
functions, and more. Moreover, once we have this understanding,
we can then reconstruct evolutionary genealogy - with even greater
confidence. In this "reciprocal illumination," causal processes reveal
insights into historical patterns, which then reveal insights into
these processes, which then reveal further insights into the patterns,
and so on. Moreover, facts about embryological development, rudi-
mentary organs, biogeography, and more can also be explained by
evolutionary processes and history. In short, a genealogical classi-
fication can provide the basis for an understanding of facts from a
broad range of organic phenomena. Darwin thought this explana-
tory power to be most important, serving as evidence for his theory
of common descent. He concludes the chapter on classification:
The several classes of facts which have been considered in this chapter, seem
to me to proclaim so plainly, that the innumerable species, genera, and fam-
ilies of organic beings, with which this world is peopled, have all descended,
each within its own class or group, from common parents, and have all been
modified in the course of descent, that I should without hesitation adopt
this view, even if it were unsupported by other facts or arguments. {Origin,
458)
IV. AFTER DARWIN
In the fifty or so years after the Origin, interest in systematics grad-
ually declined, first because a genealogical classification required
a knowledge of phylogenies that was in short supply, and second
because interest turned to other biological topics related to the cell,
biochemistry, and the mechanisms of heredity (Mayr, 217-20). But
by the early middle of the twentieth century, "evolutionary systema-
tists" such as Ernst Mayr and G. G. Simpson were following Darwin
by adopting a genealogical basis, ranking taxa according to degree
of divergence, and using assumptions about evolutionary processes
to identify homologies and analogies. Like Darwin, they assumed
that similarities that are probably due to adaptive change by natu-
ral selection are less likely to be homologies (Mayr, 212-13). By the
1970s, however, this use of process assumptions had come under
attack from two sources.
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Classification in Darwin's Origin 189
First came a challenge from "phenetics," an approach that rejected
both Darwin's theoretical assumption that classification should be
genealogical and his special similarity grouping method. Pheneti-
cists argued that classification should be an "all-purpose" way of
"storing" information about species and should therefore be based
on all characters. They classified organisms into operational taxo-
nomic units derived from a single quantity - phenetic distance -
intended to indicate overall similarity (Hull 1988, 117-30; Panchen,
132-51).
Phenetics never became widely adopted for three reasons. First, a
purely phenetic classification would typically group individuals of
different sexes and developmental stages into different operational
taxonomic units even if they were of the same species; second, differ-
ent similarity algorithms produced different operational taxonomic
units, and it was not obvious how pure observation could identify
the best algorithm; third, by combining all characters to produce a
single quantity - phenetic distance - much information was simply
being suppressed. If the goal of classification is information storage
and retrieval, as claimed, the use of phenetic distance is counterpro-
ductive.
The second challenge to the neo-Darwinian evolutionary system-
atics came from "cladistics," named for its emphasis on cladogen-
esis, the branching associated with evolution. It was based on the
approach developed by Willi Hennig, an East German entomolo-
gist, first in a 1950 textbook in German and then in a 1966 English
revision, titled Phylogenetic Systematics. Cladists (or "phylogeneti-
cists," as many prefer) returned to the Darwinian genealogical (or
phylogenetic) theoretical basis, classifying species on the basis of
ancestry, and adopting a group -in-group system based on the branch-
ing process in evolution. Cladistics places species in monophyletic
groupings - groups that contains an ancestral species, all of its
descendent species and only its descendent species. This is to be con-
trasted with par aphyletic groupings, which include only descendent
species, but not all descendent species; and polyphyletic groupings,
which include species not descendent from the ancestral species
(Hull 1988, 130-55; Panchen, 15 1-8). Monophyly as illustrated by
Hennig is shown in Figure 10.1.
Here each set of circled taxa, and the corresponding branch, rep-
resents a monophyletic group. This emphasis on monophyly has
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190
RICHARD A. RICHARDS
> I
>"
Figure io.i. The phylogenetic kinship relations between the species of a
monophyletic group, represented in two different ways (Hennig, 71). From
Phylogenetic Systematics. Copyright 1966, 1977 by the Board of Trustees
of the University of Illinois. Used with permission of the author and the
University of Illinois Press.
resulted in modifications to traditional classifications that recog-
nize paraphyletic taxa. For instance, Reptilia is not a monophyletic
grouping, as it does not contain birds or Aves, which share common
ancestry. Consequently, Reptilia is no longer recognized by most
systematists.
Cladistics is Darwinian in that it employs a genealogical theoret-
ical basis and an operational grouping method that uses only those
shared characters thought to be homologies. Cladists, though, have
rejected the Darwinian use of assumptions about evolutionary pro-
cesses to identify adaptive similarities and homologies. Instead, they
have adopted a "parsimony" approach, based on the idea that we can
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Classification in Darwin's Origin 191
take a group of taxa and identify their similarities and differences and
then use an algorithm to determine which way of grouping the taxa
requires the fewest evolutionary changes. The most parsimonious
grouping is then used to generate a branching "cladogram," that can
then be interpreted to represent the genealogy in a phylogenetic tree 1
(R. A. Richards 2007).
More recently, systematists have started to turn from pure
parsimony-based methods to statistical and molecular approaches
based on "distance" and "maximum likelihood" (Panchen, 226-37).
In part this is because parsimony seems to have its own problems.
First, there are different parsimony algorithms that generate different
groupings with no obvious way to adjudicate among them. Second,
parsimony seems to rely on problematic assumptions about the par-
simoniousness of nature and the individuation of characters (R. A.
Richards 2003). Understandably, a Darwinian- style analysis of char-
acters based on function still persists, albeit as arguably a minority
approach (Ridley 364-73).
Cladistic classification, however, is still clearly non-Darwinian
in that it rejects Darwin's approach to ranking. Darwin ranked taxa
on the basis of degree of divergence: those groups - branches - that
had apparently diverged the most from a common ancestor got a
higher Linnaean ranking - class, family, and so on. Cladists reject
this, arguing that the best classification is one based solely on geneal-
ogy or phylogeny. But if we rank solely on the basis of the branch-
ing in evolution, then wouldn't there will be an increase in rank
for each new branch? But given the staggering complexity of the
great evolutionary tree of life, the traditional Linnaean system is
fantastically inadequate - even though there are now at least twenty-
one categories from kingdom to subspecies, including subphylum,
superclass, subclass, infraclass, cohort, suborder, infraorder, super-
family, family, subfamily, tribe, and subtribe, and a proposal to add
nine more categories between the rank of family and superfamily
(Ereshefsky, 21 5 ). 2
1 Some "transformed" cladists have since taken a phenetic step backward, denying
that cladograms represent evolutionary branching - only character distributions
(Panchen, 170-81).
2 For proof of this complexity see the online "tree of life project" at <http://www.
tolweb.org/tree/.>
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192 RICHARD A. RICHARDS
While there are some efforts to revise the Linnaean hierarchy, usu-
ally these revisions make it less Linnaean, often by introducing new
categories without giving them Linnaean ranks or names. One pro-
posal, based on phyletic sequencing, simply inserts new taxa within
a Linnaean rank, but without giving them Linnaean names. Other
proposals include one to replace the Linnaean hierarchy with a pro-
cedure based on indentation, and another with positional numbers
indicating phylogenetic relationships (Ereshefsky, 241-6). At this
point, it is still not clear how to represent the innumerable branches
of the tree of life.
V. CONCLUSION
The words of Ernst Mayr at the beginning of this chapter seemed to
imply that Darwin's revolution did not extend to systematics. We
can now see in what ways that may be right and where it goes wrong.
It is right in that Darwin did not need to create a new framework
to represent genealogy. The Linnaean system was well suited to his
theoretical basis in genealogy. The group -in-group classification in
Linnaeus's hierarchical framework of species, genera, orders, classes,
and so on, could be used to represent the branching of an evolution-
ary tree, where the branches on branches represent the group-in-
group structure. It is also true that the operational approach of Lin-
naeus, as well as those of Cuvier and MacLeay, sometimes suited
Darwin's theoretical goals as well. The sexual organs that Linnaeus
used to group organisms seemed to indicate genealogy, as did the
affinities of Macleay and Cuvier. In effect, Darwin could adopt the
Linnaean hierarchy and use many of the similarities used by pre-
Darwinian systematists in the service of both his theoretical goals
and his operational methods.
But history may be misleading here. The mere fact that the Lin-
naean system was predominant both before 1800 and now does
not mean that its success has been independent of the Darwinian
revolution. At various times the systems of MacLeay and Cuvier
might well have seemed more promising. In the absence of the Dar-
winian revolution, it may be that one of those approaches might
well have become dominant. Or yet another may have come along.
The Linnaean system might well have endured primarily because it
suited the theoretical goals of an evolutionary system best. If so, the
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Classification in Darwin's Origin 193
persistence of Linnaeanism is partly a consequence of the Darwinian
revolution. But Darwin's use of the tree heuristic and its branching,
along with the cladistic rejection of his ranking procedure, may ulti-
mately still lead to the demise of the Linnaean hierarchy.
Perhaps most important here is the fact that Darwin gave system -
atics a theoretical basis, which in turn provided operational guid-
ance. In pre-Darwinian classification, it was not at all clear which
similarities should be used for grouping organisms and which should
be ignored. The placement of barnacles with mollusks on the basis
of one similarity makes as much sense as grouping them with crus-
taceans on the basis of another. Appealing to God's plan won't give
guidance unless we can know something about that plan on indepen-
dent grounds. In effect, we would need to know what God thought
about barnacles. While, in the end, we cannot know what would
have happened if Darwin had not published his Origin, it may well be
that systematists would have gone on debating indefinitely whether
nature should be grouped in three kingdoms, four embranchments,
or five circles - and why.
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LYNN K. NYHART
1 1 Embryology and Morphology
INTRODUCTION
On December 14, 1859, l ess than a month after the publication of the
Origin of Species, Darwin wrote to his confidante Joseph Hooker,
"Embryology is my pet bit in my book, &. confound my friends
not one has noticed this to me" [Correspondence, 7: 431-2). Given
the overwhelming mass of material presented in the Origin and its
range across geology, geographical distribution, artificial and natural
selection, hybridism, instinct, and classification, perhaps his friends
could have been forgiven for having failed to recognize Darwin's
pet bit. Indeed, the study of individual development in the Origin
presents something of a paradox. As a special aspect of morphol-
ogy, the study of the laws of organic form, embryology offered key
evidence for community of descent. Darwin wrote that morphology
was "the most interesting department of natural history, and may
be said to be its very soul" [Origin, 434). The comparative study
of the embryo receives similarly heavy rhetorical weight: "commu-
nity in embryonic structure reveals community of descent" [Origin,
449), and "Embryology rises greatly in interest, when we thus look
at the embryo as a picture, more or less obscured, of the common
parent-form of each great class of animals" [Origin, 450). Yet the
sections expressly on morphology and embryology together take up
less than half of a single chapter (Chapter 13), comprising only 17 of
the Origin's 490 pages, or 25 if we add the section on "Rudimentary,
Atrophied, or Aborted Organs" and the chapter summary. These top-
ics show none of the weight of detail and example displayed in, for
example, the chapters on geographical distribution and hybridism.
Although a few references to comparative anatomy and embryology
194
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Embryology and Morphology 195
may be found scattered elsewhere in the book, the space devoted to
these topics seems rather meager compared to the rhetoric attached
to their significance.
Yet Darwin insisted on such rhetoric, clinging to it even in old age.
In his Autobiography he wrote (125), "Hardly any point gave me so
much satisfaction when I was at work on the Origin, as the explana-
tion of the wide difference in many classes between the embryo and
the adult animal, and of the close resemblance of the embryos within
the same class." Not only did Darwin's friends fail to recognize it,
but historians have not known what to make of this. Just what was
it about his embryology that gave Darwin such satisfaction?
As we will see, embryology did indeed hold a key place, both in
the Origin and in his larger program, for it served as a kind of door-
way between existing ways of relating embryology to morphology
and classification and Darwin's own picture of the natural world
and the problems it posed. Morphologists studied homologies, that
is, organs they considered "the same" across different species, with
the goal of uncovering the fundamental laws of organic form, which,
they hoped, would provide for the organic realm the same kind of
foundation that Newton's laws provided for mechanics. They hoped
that such laws, in turn, would provide secure grounds for classifying
organisms and thus producing (or uncovering) the true "system of
nature." Morphology was thus understood by its leading practition-
ers across Europe and America to be, as Darwin put it, the "very
soul" of natural history. For many morphologists, the developing
individual presented a particularly compelling problem: what was
the connection to be drawn between the course of individual devel-
opment and the "affinities" or similarities seen among living groups
of organisms?
Since the early nineteenth century, naturalists had struggled to
discover these connections and wrangled with one another over their
differing answers. At one level, Darwin's theory of descent solved
this problem straightforwardly: since organisms were related to one
another, their embryonic forms, like their adult forms, could be read
as a record of their relatedness. The more similar two organisms
were in their embryological development, the more closely they
were related. Problem solved.
However, embryology was also a focal point of the new prob-
lems that Darwin's theory raised. If evolution proceeded by natural
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196 LYNN K. NYHART
selection acting upon variations among organisms, then when in
development did variation occur? How did variation affect the sub-
sequent course of development? How did natural selection act upon
the developing organism? What was the effect on the offspring of the
modified parents? And what effects might all these events have upon
scientists' reading of the embryo as a record of common ancestry (and
thus upon classification)? In the Origin, Darwin knitted together the
relations of embryology to classification and morphology, on the one
hand, and to variation, inheritance, and selection, on the other, as he
sought to recast the traditional problems of morphology in his own
terms.
CHARLES DARWIN, EMBRYOLOGIST?
Why did Darwin devote so little space in the Origin to embryology?
Shouldn't we take this absence seriously? One might argue that Dar-
win was a geologist and breeder and so had much more experience to
draw on in those areas than he did in morphology and embryology.
This argument falters on the evidence, however: Darwin was inter-
ested throughout his career in these topics (Richards 1992). Ques-
tions and notes concerning individual development appear in his ear-
liest notebooks; embryology and morphology held a significant place
in his essays of 1842 and 1844 and in his researches of the 1850s.
Already in the late 1830s and more intensively in the mid-i840S,
he began reading closely naturalists who linked classification to the
study of form, including English-language writers such as Martin
Barry and Richard Owen, French scholars such as the father-son duo
Etienne and Isidore Geoff roy St.-Hilaire and Henri Milne-Edwards,
and German scholars such as Johannes Muller. As he read, he com-
menced hands-on morphological work as well: from 1846 to 1854,
he dissected countless barnacles to establish their morphology and
classification. He directed a good deal of his attention to the devel-
opment of this creature, and he made active use of embryological
development to establish the classification of this group (Richmond
1985). Moreover, he was no tyro in vertebrate development, either.
He devoted considerable effort in the later 1850s to measuring bird
and dog neonates to determine their degree of variation as compared
with adults. So although Darwin did not base his authority as a man
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Embryology and Morphology 197
of science on his publications in embryology and morphology, he
was certainly deeply acquainted with these subjects, both from his
reading and from his own hands-on research.
But he was pressed for time. He had not yet gotten to writing up
these topics, in his deliberate way, when the threat of being scooped
by Alfred Russel Wallace hurried him into publication, causing him
to squeeze these important subjects into Chapter 13. Embryology
and morphology were undoubtedly more significant for him than
the space devoted to them in the Origin. His claims for embryology,
as for evolution in general, constituted "one long argument" that
extended well past 1859 through subsequent editions of the Origin,
Variation of Animals and Plants under Domestication (1868), and
The Descent of Man (1871).
EMBRYOLOGY IN THE ORIGIN
Darwin's main discussion of embryology appears in Chapter 1 3 of
the Origin, under the title "Mutual Affinities of Organic Beings:
Morphology; Embryology; Rudimentary Organs." The title is unfor-
tunate, for it suggests a certain grab-bag quality to the chapter, as
if he were cramming in all the subjects he hadn't gotten to yet in
order to finish the book. As true as this may be, in fact the position
of the chapter - the very last one before the book's recapitulatory
conclusion - offers a clue to its unifying and generalizing quality.
This is the chapter in which Darwin connects his theory to the nat-
ural system as a whole, in which he argues that indeed the natural
system is none other than the genealogy of nature, explained and
structured by natural selection. It is the book's punch line.
Morphology, embryology, and rudimentary organs all offer evi-
dence that the natural system is genealogical. Conversely, Darwin's
theory explains the known facts in these areas in a new and coherent
way. Here Darwin embraces within his system the most intensely
pursued questions of philosophical natural history of the previous
half -century: What is the order of nature? How are we to understand
the similarities and differences in form among different organisms
(especially animals)? How is individual development related to the
great patterns evinced by the animal world as a whole? His answer,
as with everything else in the book, is that these topics are united
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198 LYNN K. NYHART
and made coherent through the conception of descent driven by nat-
ural selection but are incomprehensible on the theory of separate
creation of species.
As he did so often, Darwin worked by first enumerating the var-
ious classes of facts that he viewed as requiring an account in his
theory. First, there was what he and his contemporaries referred to
as "unity of type" and morphological "affinities" - the fact that
organisms of the same class resembled one another in structural fea-
tures that could not be accounted for on strictly functional grounds.
These resemblances were strong, consistent, and complete enough
that morphologists, following the French museum naturalist Etienne
Geoff roy St.-Hilaire, could identify "the same" bones across the dif-
ferent vertebrates and give them the same name. Darwin's compa-
triot, the leading comparative anatomist Richard Owen, attributed
such similarities to a common "archetype," an underlying ideal
form. (In 181 8, Geoffroy called his theory covering these similar-
ities his "theory of analogues," but in 1843 Owen renamed these
similarities "homologues." "Analogous" features, in Owen's recast-
ing, were those that served the same function but used different
structures, such as the wings of insects and birds. The distinction
stuck.) Geoffroy also provided Darwin with a related idea that the
latter would run with: such homologous parts might look entirely
different and even serve different functions for different organisms,
but they shared a common underlying form. For Darwin, these sim-
ilarities were inexplicable if one assumed that different species were
independently created, but were readily assimilated into his the-
ory: homologies between organisms indicated common ancestry,
and their variants demonstrated modifications that were adaptive
to particular circumstances, culled by natural selection. His theory
of descent thus accommodated both similarities and differences in
form at one stroke.
In the case of embryology, comparison also yielded evidence favor-
ing common descent. Animals of different groups within the same
class, Darwin argued, often resembled one another more closely in
their early embryological stages than in their adult forms. For exam-
ple, embryos of mammals, birds, and frogs all shared a "peculiar
loop-like course of the arteries near the branchial slits" [Origin, 440)
despite the remarkably different conditions in which they develop -
evidence to Darwin, like adult homologies, of common ancestry. A
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Embryology and Morphology 199
close study of embryological stages could reveal surprising common-
alities. Darwin's earlier examination of barnacle (cirripede) embryos
not only showed that the embryos were much more similar than the
adult forms, but also demonstrated to his satisfaction that they were
crustaceans, although their widely varying adult forms, most often
encased in a calcareous fortress attached to a rock, did not reveal this
fact so clearly [Origin, 440). (Indeed, Darwin's longtime foe Richard
Owen, who favored comparison of adult forms over that of devel-
oping forms in establishing homologies, considered cirripedes as a
distinct class, which he placed between the Crustacea and Annel-
ida [Richmond 1985, 394].) However, embryos did not always show
ancestral resemblances, and sometimes earlier developmental stages
could even appear higher in organization than mature ones.
After summarizing these diverse facts, Darwin came to the point:
How, then, can we explain these several facts in embryology, - namely the
very general, but not universal difference in structure between the embryo
and the adult; - of parts in the same individual embryo, which ultimately
become very unlike and serve for diverse purposes, being at this early period
of growth alike,- - of embryos of different species within the same class,
generally, but not universally, resembling each other,- - of the structure of
the embryo not being closely related to its conditions of existence, except
when the embryo becomes at any period of life active and has to provide for
itself; - of the embryo apparently having sometimes a higher organization
than the mature animal, into which it is developed. [Origin, 442-3)
Not surprisingly, his answer was that "all these facts can be ex-
plained, as follows, on the view of descent with modification" [Ori-
gin, 443). And several pages later, he was still more blunt: "the
embryo is the animal in its less modified state; and in so far it reveals
the structure of its progenitor. . . . Thus, community in embryonic
structure reveals community of descent" [Origin, 449).
At a general level, Darwin's argumentative strategy here was in
line with his handling of other classes of facts throughout the Origin,
in which common descent and natural selection accounted for a
wide variety of phenomena in nature for which the theory of inde-
pendent species creation had a less satisfactory explanation (or none
at all). But there was a practical point, too, that tied these subjects
together. "We have no written pedigrees," Darwin noted [Origin,
425); "we have to make out community of descent by resemblances
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200 LYNN K. NYHART
of any kind. Therefore we choose those characters which, as far as
we can judge, are the least likely to have been modified in relation
to the conditions of life to which each species has been recently
exposed." To establish true evolutionary relationships - the now-
transformed task of classification - the naturalist must seek clues
to ancestry in the commonalities of form, by definition those that
had changed least over time. Some of these commonalities would
be found in structures so vital to the organism that they could not
change much at all, but other characters could also reveal those
commonalities, provided they had not been modified through natu-
ral selection. Embryonic forms were often protected from selection,
in Darwin's view, if they were in eggs or wombs or otherwise not
actively exposed to the struggle for existence. Developing forms not
only revealed the fact of common descent, then, but could also pro-
vide the clues to specific questions of classification.
But there was still more to Darwin's discussion. Right after he
listed the main embryological facts he sought to explain (given in
the long quotation cited earlier), he introduced some new issues. A
long paragraph addressed the question of when variations appear in
individual development, and concluded that
it is quite possible, that each of the many successive modifications, by which
each species has acquired its present structure, may have supervened at a not
very early period of life; and some direct evidence from our domestic animals
supports this view. But in other cases it is quite possible that each successive
modification, or most of them, may have appeared at an extremely early
period. [Origin, 444)
In other words, modifications could appear early on or not. "[A]t
whatever age any variation first appears in the parent," Darwin con-
tinued, it seemed likely to him that "it tends to reappear at a corre-
sponding age in the offspring." Elevating these two statements - the
first quite vague, the second more specific - to principles, Darwin
wrote that they could account for "all the above specified leading
facts in embryology" [Origin, 444).
What was going on here? Why did Darwin insist that the moment
at which variation appears is an important issue, and that the corre-
sponding age of appearance in the offspring was also something that
needed to be confronted? The answer, I believe, is that introduc-
ing these considerations allowed him to do three things that would
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Embryology and Morphology 201
assist in translating embryology into his new framework. First, he
sought to account for what had formerly been seen most often as the
product of a transcendental Law of Development in historicist and
materialist terms, by explaining just how embryos might come to
reveal their ancestral history. Second, to do this, he needed to con-
nect his understanding of the embryo-ancestor relationship to other
elements of his theory, especially variation, selection, and inheri-
tance. And third, he sought to account in these same terms not only
for cases in which embryos revealed the organism's ancestry but
also for cases in which they did not, for embryos' developmental
stages could bear complex relationships to variation, selection, and
the representation of ancestry. Darwin's two principles of embryol-
ogy and inheritance provided a crucial hinge-point between solving
an old problem - the nature of the relationship between embryolog-
ical development and classificatory affinities - and resituating that
problem itself within a framework that decentered its importance.
EMBRYOS AND THE ORDER OF NATURE
Darwin was well aware of the different kinds of relationships his con-
temporaries and predecessors had drawn between individual devel-
opment and the order of nature. The choices were far more diverse
than the stark opposition between creation and descent that he
posed in the Origin, and the means of choosing among them not at
all clear-cut. Many naturalists, especially in the German-speaking
lands, believed that there was a general "law of development" in
nature that governed both individuals and the overall history of life.
In such formulations, typically, individual development reflected a
macrocosmic trend toward increasing progress and complexity. Con-
versely, naturalists thought (though not without contestation), they
could be confident of the overall increase in progress and complexity
of the broader organic world that was gradually being revealed in the
fossil record in part because they saw a parallel in the individual
embryo (Richards 1992; Nyhart 1995; Gliboff 2008).
Many naturalists shared this broad conviction, but not all were
so certain that simply positing a "law" of development was a sat-
isfying way to account for the parallels. What did it mean to say
that such a law "governed" both the development of the organic
world as a whole and individual development? Was this law simply
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202 LYNN K. NYHART
an empirical generalization, or did it have causal efficacy? If the lat-
ter, how did that causal connection work? Many naturalists sought
a more specific connection between the pattern of development of
embryos and the larger patterns of organic nature as a whole, even
as they were working out the details of both. Two ways of con-
necting up these two patterns had become prominent by the mid-
1 840s, when Darwin started to engage the topic with some intensity.
One approach, which we will call the recapitulationist approach,
took a primarily linear perspective on both the order of nature and
the understanding of individual development. This view held that
as individuals developed, they worked their way up the chain of
being from less to more complex. This was the perspective held by
Friedrich Tiedemann, who believed that the brains of mammalian
fetuses passed through the adult stages of the lower vertebrate classes
as they advanced in development. Darwin would have been famil-
iar with this approach as far back as his reading of Charles Lyell's
Principles of Geology, for in volume 2, Lyell (1832; reprint 1991)
noted Tiedemann's finding, "most fully confirmed and elucidated
by M. Serres, that the brain of the foetus, in the highest class of ver-
tebrated animals, assumes, in succession, the various forms which
belong to fishes, reptiles, and birds, before it acquires those additions
and modifications which are peculiar to the mammiferous tribe."
Lyell specifically characterized Tiedemann's views as transformist:
"So that in the passage from the embryo to the perfect mammifer,
there is a typical representation, as it were, of all those transforma-
tions which the primitive species are supposed to have undergone,
during a long series of generations, between the present period and
the remotest geological era" (Lyell 1991, 63). Tiedemann's argument
was reinforced by Serres and several other important French stu-
dents of development, who interpreted monstrosities as "arrests of
development." That is, many monsters resulted from a failure to
develop beyond a certain lower stage of development that paralleled
the hierarchy of being. The logical connection between monstros-
ity and transformism was this: monstrosities subtracted levels of
complexity from the end of their development, stopping earlier and
representing a lower form. Perhaps all a creature needed to do in
order to create a newer, higher form was to extend the end of its
development. However, Lyell objected, animals in fact "never pass
the limits of their own classes to put on the forms of the class above
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Embryology and Morphology 203
them. Never does a fish elevate itself so as to assume the form of the
brain of a reptile; nor does the latter ever attain that of birds; nor the
bird that of the mammifer" (Lyell 1991, 63). The logic of inversion
was false.
This linear view, which had earlier incarnations, had previously
been objected to, perhaps most famously by the Estonian "father of
embryology" Karl Ernst von Baer. Von Baer's alternative, just becom-
ing available to British naturalists in the early 1 840s, did two things.
It rejected a single scale from monad to man, supporting instead the
view of Georges Cuvier, France's leading zoologist, that there were
four basic and distinct kinds of organization in the animal kingdom
(called "Types" by von Baer and "Embranchements" by Cuvier). Von
Baer's view further interpreted development as a successive process
of differentiation that paralleled the successively smaller classifi-
catory groups to which an individual belonged. The embryo first
exhibited the characteristics of the vertebrate Type, then its class
(e.g., bird), then the order, and so forth down to the individual.
Although Darwin had encountered this view by 1838, he was
most struck by the gloss on it presented by Henri Milne-Edwards in
an 1844 article, which Darwin read in 1846, just as he was begin-
ning his barnacle work. To the general idea that the embryo first
exhibited the broadest characteristics of the Type and then succes-
sively the more particular characteristics of the class, order, genus,
and species, Milne-Edwards added the corollary that the more char-
acteristics two organisms shared in development, the more closely
were they related. Embryology could thus be used to ascertain how
closely or far apart two organisms should be classified.
Echoing the divisions of the nineteenth century, historians have
long viewed the two systems of linear recapitulation and devel-
opmental differentiation as sharply distinct and opposed to one
another. Recapitulation went with the linear view and a strong
notion of absolute progress; differentiation was associated with
branching and specialization. Yet Darwin, and at least one naturalist
before him, thought that they could be reconciled. To see how, we
must note one key issue to which historians have devoted intense
scrutiny. To what, exactly, did naturalists compare the stages passed
through by present-day embryos of higher forms?
There are four possibilities. The stages of present-day higher
embryos might be comparable to present-day adults (especially of
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204 LYNN K. NYHART
lower forms), to present-day embryos, to adults of past forms, or to
embryos of past forms. In the pre-Darwinian linear recapitulation-
ist perspective, early stages of present-day embryos were compared
to present-day adults of lower forms; in Tiedemann's presentation,
these also "represented" or were presumed to be analogous to (or
even "the same as") adults of past forms. The differentiationist point
of view compared embryos only to other embryos, not to adults.
Von Baer and Milne-Edwards were mainly interested in comparisons
among living organisms, not in interpreting past organisms. No one
was talking about comparing present-day embryos to embryos of
past forms - until Vestiges, it would appear.
In 1844, the anonymous author of the Vestiges of the Natural
History of Creation sought to draw explicit parallels (and connec-
tions) across fetal brain development, the present-day hierarchy of
organic complexity, and the fossil record. The parallels, represented
in his accompanying chart, appear clear: the human fetus's resem-
blance in the fifth month to that of a rodent lines up exactly with
the appearance of Rodentia in the lower Eocene. It would seem as
though the author of the Vestiges wanted the embryological stage
to resemble a past adult. Yet the Vestigiarian's language on the ana-
logical target of embryological resemblance was mixed. On the one
hand, he declared straightforwardly, "It is only in recent times that
physiologists have observed that each animal passes, in the course
of its germinal history, through a series of changes resembling the
permanent forms of the various orders of animals inferior to it in the
scale" (Chambers 1994, 198). On the other hand, he later stated (212),
"But the resemblance is not to the adult fish or the adult reptile, but
to the fish and reptile at a certain point in the foetal progress." Fur-
thermore, as represented in an accompanying diagram (Figure 1 1 . 1 ),
his concept of development was not strictly linear: each class within
the vertebrates followed a common path to a certain point and then
branched off into a path unique to its group. Struggling to accom-
modate both a linear perspective and a branching one, he imagined a
main line of ascent leading to humans, which lower types partially
followed before branching during their development.
[I]t is apparent that the only thing required for an advance from one type
to another in the generative process is that, for example, the fish embryo
should not diverge at A, but go on to C before it diverges, in which case
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Embryology and Morphology 205
M
D
C
Figure 11.1. Representation of development, in which an embryo fat A) that
might develop into a fish fat F), continues to advance (through C, D, and
M), giving rise over time to reptiles, birds, and mammals (R, B, and M) ;
from Chambers's anonymously published Vestiges of the Natural History
of Creation (1844).
the progeny will be, not a fish, but a reptile. To protract the straightforward
part of the gestation of a small space - and from species to species the space
would be small indeed - is all that is necessary. (Chambers 1994, 213)
This was a critical early instance of a scientific writer seeking to
combine a linear view of progress with a branching conception of
development. As much as Darwin may have detested the Vestiges,
it constituted part of the picture he was gleaning as he developed his
own ideas during the key period of the mid-18408, and it may have
given him something to think about.
So, what did Darwin think? To what did he believe present-day
embryological development should be compared?
DARWIN AND EMBRYOLOGICAL RESEMBLANCE
Historians differ in their interpretations of Darwin's views on
the recapitulationist versus differentiationist understandings of the
embryo. Most follow the argument first set out by E. S. Russell
in 1 91 6 and reinforced sharply by Stephen Jay Gould in 1977, that
Darwin rejected the former in favor of the latter. In 198 1, Dov Ospo-
vat refined this view, arguing that Darwin followed the linear reca-
pitulation model in his early work but that in the mid- 1 840s he was
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206 LYNN K. NYHART
persuaded by more recent work, especially that of Milne-Edwards,
arguing that successive differentiation more accurately expressed
the parallel between embryos and the larger order of nature. Broadly
interpreted within Darwin's developing framework, branching and
differentiation in embryonic development mirrored the branching
and differentiation in varieties, species, and the larger classifica-
tory hierarchy. In this interpretation, embryos resembled neither
the adults of lower present-day types nor historical adults, but only
other embryos, present-day and in the past (Ospovat 1981, 166-7).
By contrast, Robert J. Richards has argued (1992) that Darwin
believed that present-day embryos tended to resemble ancestral
adults. In this view, embryonic stages revealed a sequence of adult
ancestors - more primitive stages of development in the historical
development of life. Critical to this interpretation is a strong read-
ing of Darwin's two principles of embryology and inheritance. If one
understands the first principle, that new variations "supervene at a
not very early period of life," to mean that such variations appear as
end stages of development, and then, following the second principle,
they reappear at a "corresponding stage in the offspring," it follows
that new evolutionary variations will be tacked on to the end of indi-
vidual development in subsequent generations. Stephen Jay Gould
dubbed this the doctrine of "terminal addition" (though he excluded
Darwin from his list of recapitulationists who took this view). By
this logic, a present-day individual will run through adult ancestral
stages as it goes through development because that is how the devel-
opmental sequence itself came into being, by adding new stages to
the end of what was a mature (if primitive) organism. In Richards's
reading, Darwin was a recapitulationist, who viewed present-day
embryos as primarily comparable to ancestral adults.
Few historians have agreed with this interpretation of Darwin
as a recapitulationist, for that would seem to tie his ideas to linear
thinking rather than branching, and to a progressive hierarchy rather
than a view of change as differentiation (see, e.g., Bowler 2003 ). After
all, Darwin made repeated statements such as "the embryo is the
animal in its less modified state. ... In two groups of animal, however
much they may at present differ from each other in structure and
habits, if they pass through the same or similar embryonic stages,
we may feel assured that they have both descended from the same
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Embryology and Morphology 207
or nearly similar parents. . . . "[Origin, 449). Surely this is evidence
for differentiation, and for embryos resembling embryos rather than
ancestral adults.
But Darwin also offered the example of the forelimbs becom-
ing modified in different directions over evolutionary time from a
common ancestral pair of legs, becoming in different descendants
hands, paddles, and wings:
and on the above two principles - namely of each successive modification
supervening at a rather late age, and being inherited at a corresponding late
age - the fore-limbs in the embryos of the several descendants of the parent-
species will still resemble each other closely, for they will not have been
modified. But in each individual new species, the embryonic fore-limbs will
differ greatly from the fore-limbs in the mature animal; the limbs in the
latter having undergone much modification at a rather late period of life,
and having thus been converted into hands, or paddles, or wings. [Origin,
447)
Clearly, differentiation is occurring here, but the stress on the "rather
late age" and on the modifications "being inherited at a correspond-
ing late age" (the two principles) can also be read as Darwin insisting
on terminal addition as the means by which this differentiation took
place, and as the reason why embryos resemble one another.
In fact, the contradiction between linearity and branching is only
apparent, and may be resolved. Darwin did so, and it is reasonable
to believe that he did so via adult ancestors. If two organisms have
a common ancestor, then that adult ancestor may be both the end
product of a particular course of development (up to that point) and
an earlier stage of the existing course of development of a present-day
organism. The doctrine of terminal addition is not necessarily tied
to a strictly linear view of nature, but is compatible with a branching
one. 1
To see this most clearly, consider that both development and evo-
lution may be viewed from two ends: from the base of a branching
Darwinian tree, or from a twig at the living end. From the base,
moving upward, we see branching. But looking back from that twig,
1 I have made a similar argument in explicating Ernst Haeckel's views on recapitula-
tion (Nyhart 1995, 134-5).
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208 LYNN K. NYHART
the organism views a linear history back into the past - the history
that led to itself. From another endpoint/twig, a different organism
also sees a linear history leading backward. Where these two lines
meet in a common ancestor, their two backward-leading histories
become one. Branching is what we see as we move forward; linearity
and joining are what we see as we move backward in time.
From Darwin's standpoint of evolutionary recapitulation, the
same held true in individual development. Individual development,
read forward from the deep past, would take place as follows: as evo-
lutionary history proceeded, new variations would tend to be added
on to the end of embryonic development. Natural selection would
then tend to cause divergent variations to be selected, following
Darwin's principle of divergence. Thus as new stages were added
on to individual development, incipient evolutionary divergence
would simultaneously take place. Suppose that two different end-
stage variants eventually resulted in two new, modified species.
Each would be able to trace back through its individual develop-
ment a record of its own evolutionary history, and these two courses
of individual development would join up at the point at which the
evolutionary histories joined up. So embryos would tend to share a
longer common developmental history the more recently they had
branched off from one another, and even embryos of the same class
(but of different families and orders) would tend to share common
features at the very beginning of their development, reflecting their
distant and early common ancestry.
Although Darwin said all of these things separately, it is diffi-
cult to find him putting the whole picture together - which may be
one reason why his friends (and most later historians) did not fully
appreciate his achievement. Yet if this reasoning is correct - and I
am convinced that this does indeed reflect an important part of
Darwin's reasoning - then his achievement with respect to embryol-
ogy was substantial indeed. Darwin resolved the opposition between
the linear and diff erentiationist approaches to the problem of embry-
onic resemblance, and he did so within his own framework of evo-
lution by natural selection working on variations. All it took was a
couple of ancillary principles to make the shift.
And yet I would suggest that this was not what satisfied Darwin
himself most about his interpretation of embryology. His two prin-
ciples of embryology and inheritance not only explained embryos'
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Embryology and Morphology 209
resemblance to other embryos and to ancestral adults but also offered
an account of the very nature of development itself.
Consider what Darwin remembered in his Autobiography: he was
especially proud of his "explanation of the wide difference in many
classes between the embryo and the adult animal, and of the close
resemblance of the embryos within the same class" [Autobiography,
125 ). What constitutes "the wide difference in many classes between
the embryo and the adult animal"? Development. Terminal addi-
tion plus inheritance at a corresponding age explained development
itself: "This process, whilst it leaves the embryo almost unaltered,
continually adds, in the course of successive generations, more and
more difference to the adult" [Origin, 338). This was why embryos
resembled ancestors. But it was also why organisms developed at
all: development was a consequence of the process of evolution. By
using his two principles, Darwin could derive from evolution the
very process of development.
DEVELOPMENT, VARIATION, SELECTION,
AND INHERITANCE
Darwin's two principles did not just allow him to establish a mate-
rial connection between individual development and evolution; they
worked to weave this connection deeply into the vocabulary of his
overall theory. The idea that modifications tended to supervene at
a not- very-early stage of life was a claim about variation, a central
component of his theory. That such modifications would tend to be
inherited at a corresponding age in the offspring was a claim about
heredity. Both were entwined in the physiological problem-complex
of development, variation, and inheritance, known at the time as
"generation," one of Darwin's most abiding interests, which would
culminate in his hypothesis of pangenesis, published in 1868 (see
Hodge 1985; Sloan 1985). These concerns plunged him into the nitty-
gritty of the material processes by which organisms might become
transformed over time.
The mass of facts he had gathered before him did not present
a simple picture. Discerning regularities among the varied facts of
heredity and variation was one of Darwin's most intractable prob-
lems. His need to wrestle with this problem was part of what made
Darwin's interest in and claims about development different from
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210 LYNN K. NYHART
those of his morphologist predecessors, and ultimately what reduced
its place in his overall system from the central topic to one among
several important areas of consideration.
Despite the stronger claims he sometimes made at moments of
summary, Darwin's discussion of embryology and variation was
filled with equivocation. Virtually every single time he discussed
the tendency of variations to supervene at a late stage of develop-
ment, he followed with a counterexample: they could also appear
at an early stage. Or development might not proceed very far at
all. Everything was qualified; Darwin's language was littered with
expectation-lowering phrases. "It is quite possible" that new char-
acteristics "may" have appeared late in life. But then again, it was
"quite possible" that they may not have.
This equivocation has two important aspects: one has to do with
Darwin's confidence in his claims, the other with their generality.
First, at the time of writing the Origin, Darwin appears not to have
been fully confident about the temporal relationship of variation
to development. He hinted at the difficulty he faced in coming to a
resolution at the beginning of the passage introducing his two princi-
ples of embryology and inheritance, when he treated the assumption
that "variations necessarily appear at an . . . early period" - a view
he opposed, but without complete conviction. It turns out that his
equivocation was significant, and that Darwin had changed his mind
from an earlier, opposing position. The story of Darwin's shifting
stance shows his lack of certainty about the relation of modification
to development, his continued efforts to link this problem up with
classificatory relationships, and his desire to connect both issues to
selection.
As early as his "Sketch" of 1842, Darwin had suggested that vari-
ations could enter in at different times during development, but that
it did not matter just when they did so if they were protected from
selection [Foundations, 42). In his 1844 "Essay," he elaborated upon
the point, noting that all that counted was that an adaptive struc-
ture be in place at a time when selection could act to preserve it,
which typically occurred only in the mature state. Thus if it could be
shown that variation did not always take place early on in develop-
ment but tended to take place later on, and that selection too tended
to take place at later stages, this would account for differences in
the adult organism; at the same time, the lack of selection at early
stages would leave those early stages resembling one another more
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Embryology and Morphology 211
than their mature forms [Foundations, 220-7). Darwin's measure-
ments of newborn greyhounds and bulldogs showed their legs and
noses to be the same length, confirming that even greatly varying
breeds resembled one another more closely at birth. (In the 1850s,
he would gain further confirmation of his views with measurements
of neonate pigeons.) Using his characteristic analogy between artifi-
cial and natural selection, he argued that if nature's selective hand
worked on mature individuals as human selection did, then it would
make sense that in nature, too, younger individuals would tend to
resemble one another more than adults.
However, in the manuscript of his "Big Book" - the one for which
the 490-page Origin served as a mere abstract - Darwin changed
his position, based on reading he had done just after his 1844 essay.
There he wrote that "modifications in the mature state will almost
necessarily have been preceded by modification at an earlier age"
(Species Book, 302). He then cited the French entomologist Gaspard
Auguste Brulle, who in 1844 had argued that the more complex an
organ would become in its adult stage, the earlier it must appear
in development. The botanist Francois Marius Barneoud had found
something similar in plants. Darwin then immediately turned to
discussing Milne-Edwards's 1844 paper, which used the criterion of
embryological differentiation to establish classificatory affinities. As
Darwin interpreted Milne-Edwards, "the more widely two animals
differ from each other, the earlier does their embryonic resemblance
cease" [Species Book, 303). Darwin concluded the section with the
following:
If the foregoing principle be really true &. of wide application, it is of impor-
tance for us,- for then we might conclude that when any part or organ is
greatly altered through natural selection it will tend either actually first to
appear at an earlier embryonic age or to grow at a quicker rate relatively to
the other organs than it did before it had undergone modification.: conse-
quently, . . . this early formation will tend to act on the other & subsequently
developed parts of the system. [Species Book, 304)
Darwin copied out this section of his manuscript and sent it to
Huxley for review on July 5, 1857.
Especially I want your opinion how far you think I am right in bringing in
Milne Edwards['] view of classification. I was long ago much struck with
the principle referred to: but I could then see no rational explanation why
affinities should go with the more or less early branching off from a common
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212 LYNN K. NYHART
embryonic form. But if MM Brulle and Barneoud are right, it seems to
me we get some light on Milne Edwards['] views of classification; and this
particularly interests me. [Correspondence, 6: 420-1)
What exactly Darwin thought that light would be remains
unclear. In his reading notes on Milne-Edwards's article in the mid-
1 840s, Darwin had written that "to mature an organ, a certain time is
required, &. that the earlier changes can alone be hurried. This at once
nearly explains the gradual loss of embryonic characters. ..." [Cor-
respondence, 4: 393). By 1857, his worrying over the problem may
have made its implications more expansive: perhaps he inferred that
complex forms - those most modified from an ancestral one - would
share an embryonic resemblance only early in development. This
would associate early branching from a common ancestor (Darwin's
interpretation of Milne-Edwards) with modification at an early stage
of development. In any case, it is clear that Darwin was working to
combine and reconcile the results of Brulle and Milne-Edwards while
also translating them into his own terms. At this moment, in 1857,
he was thinking that new variations normally supervened early in
development, not at the end. (Rachootin [1984] treats at length how
Darwin developed Brulle's ideas.)
Huxley's reply was scathing - as he put it, he "bruler'd Brulle,"
arguing that every bit of the latter's evidence was wrong and that his
logic was, if anything, worse. Moreover, he corrected Darwin's appar-
ent interpretation of Milne-Edwards: "he seems to me to say that,
not the most highly complex, but the most characteristic organs
are the first developed" [Correspondence 6: 424-7). Thus Brulle's
argument did not reinforce Milne-Edwards's, as Darwin would
have it.
Darwin not only omitted the passage in the Origin but, as we have
seen, tilted in the opposite direction, returning to his views of the
early 1840s. Significant new variations tended to appear not early
in development but late. This he put to work to explain embryos'
resemblance to ancestors (and, significantly, this discussion appeared
in the chapter on affinities, morphology, and classification, not in
the chapter on laws of variation, as had the earlier version in the
big species book). Yet the uncertainty remained - Brulle had found
cases where modifications seemed to supervene early, and Darwin
continued to take those instances seriously. The general rule that
he came up with in the end was not one in which embryos must
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Embryology and Morphology 213
mirror ancestors or must retrace the successive features of the class,
the order, the genus, and the species. Instead, it was one that empha-
sized contingency, variation, and the intervening hand of natural
selection.
And this brings us to the other aspect of Darwin's equivocation
over the timing and nature of the appearance of heritable modifi-
cations in development: the question of their generality. Darwin
wanted to account not only for those cases in which embryos of
related forms resembled one another, but also for cases in which
they did not, as well as for different amounts and moments of resem-
blance. To succeed, his framework had to accommodate all the differ-
ent cases. So he proceeded to show how they all might be understood
as the product of evolution by natural selection acting on variations,
whenever they might appear.
Sometimes embryological development exhibited a succession of
modified ancestral adults. This would be the case in many verte-
brates, especially in those organisms, such as birds and mammals,
that were protected from the pressures of selection in the egg or
womb, where there had been much modification from an original
primitive ancestor, and where successive modifications were inher-
ited at a corresponding age in the offspring. But in some organisms,
early developmental stages did not benefit from the protections of
egg or womb and had to fend for themselves. The pressure of selec-
tion on these free-living larval forms meant that adaptations would
appear earlier on in development, tending to efface ancestral con-
nections [Origin, 440) and also in some cases producing distinct
metamorphic stages [Origin, 448). In yet other cases, embryos could
display variations early on in their development that made them
resemble more closely the adult forms. Drawing on his own research
measuring pigeon neonates, Darwin noted that this was the case in
the short-faced tumbler pigeon, which revealed its adult facial char-
acteristic at the moment of hatching, whereas other pigeon varieties
all closely resembled one another when newly hatched. He used this
case to move away from the question of ancestral resemblance to
focus more closely on a larger group of cases in which there was lit-
tle developmental difference between young and adults; and again,
he explained these cases via the pressure of selection. If the young,
instead of being protected from selection, were exposed to the same
environmental pressures as their parents, they would tend to display
early on in development the same adaptive characteristics.
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214 LYNN K. NYHART
In this discussion, the resemblance of some embryos to ancestors
represented one pattern among many - the only one that required
modifications to supervene at "a not very early period of life." It
may have been Darwin's default pattern, but the others were also
significant and demanding of explanation. One way or another, evo-
lution by natural selection could account for all the various patterns
of development seen in the organic world. 2 Embryo-ancestor resem-
blance was one important consequence of evolution, and Darwin's
theory explained it in a nonidealistic way. But in Darwin's scheme,
all those other developmental patterns required - and received -
explanation in evolutionary terms.
In the fourth edition of the Origin (1866), Darwin clarified and
strengthened his claims about recapitulation, while also broaden-
ing his discussion of nonrecapitulatory cases. Thus he explicitly
mentioned that embryonic resemblance corresponded to an adult
ancestor:
[I]t is probable, from what we know of the embryos of mammals, birds,
fishes, and reptiles, that [these animals] are the modified descendants of
some one ancient progenitor, which was furnished in its adult state with
branchiae, had a swim-bladder, four simple limbs, and a long tail fitted for
an aquatic life. [Variorum, 702, 306. 10. d)
Crustaceans showed a similar phenomenon. Here Darwin leaned
heavily on a small book, Fur Darwin, published in 1864 by the
German emigre zoologist Fritz Muller, who lived in Brazil and had
closely studied the Crustacea there. In his book, Muller demonstrated
a common larval stage for a range of crustaceans with widely differ-
ing adult states and argued that this larval stage represented an adult
common ancestor. His position, based on impeccable embryological
research, so pleased Darwin that he paid for the translation and pub-
lication in English of Muller's little book (Muller 1869; West 2003,
1 20-1). The fourth and later editions would be peppered with new
references to Muller.
Even as he clarified his claim that embryos resembled adult ances-
tors, however, he also expanded his discussion of cases in which
they did not. Again, the fourth edition elaborated further on cases
Darwin included plants in his discussion but devoted much less space and attention
to them.
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Embryology and Morphology 215
of early adaptation, especially in insects - cases, for example, in
which the need to survive in unprotected environments produced
distinct metamorphic stages, which might sometimes be "higher"
than later ones. Thus, to his first-edition declaration that "commu-
nity in embryonic structure reveals community of descent" [Origin
449), he added, "but dissimilarity in embryonic development does
not prove discommunity of descent, for in one of two groups all the
developmental stages may have been suppressed, or may have been
so greatly modified as no longer to be recognized, through adapta-
tions, during the earlier periods of growth, to new habits of life"
[Variorum 703, 3i2:d) Adaptation and selection would account for
cases in which embryos did not reveal their ancestral heritage.
From first to last, Darwin believed that when embryos resem-
bled others of related classificatory groups, they did so because they
shared a common ancestry. But his understanding of variation, selec-
tion, and the general contingency of nature led him away from an
understanding of morphology as the study of the laws of form in the
strict sense of earlier (and later) continental morphologists. Nature
did not make laws of form. She might have some rules governing
form - frequent regularities - but these could be broken, and the
organic world was littered with such breakage. The only law was
evolution; all else was contingent. Even as Darwin solved the prob-
lem of embryology and ancestral affinity, he dissolved it into the
larger complex of evolution by natural selection.
Cambridge Collections Online © Cambridge University Press, 2009
VASSILIKI BETTY SMOCOVITIS
12 Darwin's Botany in the Origin
of Species
He moons about in the garden, and I have seen him stand-
ing doing nothing before a flower for ten minutes at a time.
If he only had something to do, I really believe he would
be better.
- Charles Darwin's gardener 1
darwin's botany: introduction
Taxon-based studies defined much of natural history in the nine-
teenth century, with botany and zoology serving as the two major
realms of such inquiry. Darwin himself was taxonomically promis-
cuous, flitting from organism to organism much as his curiosity
dictated but also out of a utilitarian need for particular examples to
support a generalizable theory that explained the diversity of living
organisms. Thus, in the course of his scientific career Darwin studied
a range of organisms and familiarized himself with related sciences
like geography and geology. But increasingly after the Origin, his life-
long interest in botany not only revealed itself but came to dominate
his research.
That interest had started early. In fact, one could say that he inher-
ited it; his grandfather Erasmus was a translator of Linnaeus, while
another relative, John Wedgewood, was one of the founders of the
Royal Horticultural Society. Almost serving as a prophetic image of
the role that botany would play in his life, an early portrait of the
young Charles shows him seated next to his sister Catherine hold-
ing a pot of plants. At the age of twelve or so, he was given the task
1 As cited in Morris et al. (1987, 48).
216
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Darwin's Botany in the Origin of Species 217
of counting peony blossoms in his father's garden; and later, while
engaged in what became a failed study of medicine, he was exposed
to the study of materia medica (or plants known to be useful for
medical or healing purposes) (Kohn 2008b). As a young Cambridge
student, Darwin formally studied with John Stevens Henslow and
spent so much time with him that he became known as "the man
who walks with Henslow." Under Henslow's tutelage, he performed
anatomical dissections on plants like Geranium, and familiarized
himself with taxonomic studies (Kohn 2008b). His exposure to
Henslow's herbarium and to its special emphasis on "collated" speci-
mens, which stressed multiple collections, was especially important.
It helped lay the groundwork for his understanding of variation and
indeed for his understanding of speciation (Kohn et al. 2005).
Later, while exploring unfamiliar terrain during the Beagle's vari-
ous layovers in South America, Darwin collected numerous spec-
imens of local floras and sent them back home for permanent
storage as well as identification. Later still, while enjoying his
life as the celebrated "squarson-naturalist" of Downe, he began to
undertake detailed observational and experimental studies on select
plants. Recognizing their importance to his larger theoretical project,
Darwin also formed strong professional ties with leading system-
atic botanists of his day such as Joseph Hooker, the director of Kew
Gardens, and Asa Gray, a botanist at Harvard University. He also cul-
tivated an extensive correspondence network with breeders, horti-
culturalists, collectors, and compilers of floras the world over. These
professional networks helped fuel his growing interest in plants,
especially by providing some of the best examples in support of his
theory of descent as set forth in the Origin of Species. 2
Plants lent themselves readily to Darwin's investigations as exam-
ples in support of his theory, but they were especially valuable for
the kinds of observational and experimental studies that charac-
terized his research in the mature phase of his career. They were
tractable "model organisms" (to use a presentist term), easy to grow
(depending on the plant chosen) and stationary (and therefore easy
to observe); knowledge of them from horticultural, agricultural, and
The critical year for Darwin's shift to botany is i860. See David Kohn, "Darwin's
Botanical Research," in Morris et al. (1987, 50-9). For an overview of Darwin's life
and work, see Janet Browne (1995 and 2002).
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2l8 VASSILIKI BETTY SMOCOVITIS
breeding practices was well developed by the middle decades of the
nineteenth century, as was knowledge of their morphology, anatomy,
and even cytology thanks to new microscopic, sectioning, and stain-
ing techniques. Plants additionally bore a staggering assortment of
vegetative and reproductive structures, with complex mating pat-
terns that included self-fertilization, cross-fertilization, and elabo-
rate pollination mechanisms. These last often required other organ-
isms, like insects and birds, thus making them ideal for studies of
co-adaptation. And with what we now recognize as "open" or inde-
terminate growth patterns that reflected readily the direct effects of
the environment, plants also drew attention to the general process of
adaptation, making them ideal systems for exploring the direct and
indirect effects of the environment (Briggs and Walters 1997). For
all these reasons, Darwin increasingly devoted his efforts to draw-
ing on the study of plants not only to fortify, but also to extend his
theoretical insights as first developed in the Origin.
Though it would be hard to consider Darwin a botanist in the
strict sense of the term, he employed examples of plants in at least
three interrelated ways: (a) in his thinking about evolution, (b) in his
own researches, and (c) in his professional life as a whole. By the end
of his long and productive career, he had completed no less than six
books exclusively devoted to botanical subjects, published between
the years 1862 and 1880, in addition to botanical articles published in
the weekly Gardener's Chronicle and journals like the Agricultural
Gazette (Ornduff 1984). Some drew extensively on the work of col-
leagues, while others drew exclusively on his own observations and
experiments performed in the hothouses and experimental gardens
of his home in Downe (Morris et al. 1987).
PLANTS IN DARWIN'S ORIGIN OF SPECIES
The importance of plants for Darwin's theory is manifested by their
prominent appearance in the first four chapters of the Origin, the
chapters that lay the groundwork for his theory of descent. Plants do
not figure significantly in the chapters on geology (Chapters 9 and
10) or in the chapter dealing with instinct (Chapter 7); but in all other
chapters of the Origin, plant examples appear frequently, custom-
arily following mention of a phenomenon demonstrated in animals.
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Darwin's Botany in the Origin of Species 219
As early as the very introduction to the Origin, Darwin set this
comparative rhythm in motion by making reference to how "prepos-
terous" it would be to attribute to "mere external conditions, the
structure, for instance of the woodpecker, with its feet, tail, beak,
and tongue, so admirably adapted to catch insects under the bark of
trees" ( Origin, 3 ). He immediately followed the animal example with
a comparable plant example, the "misseltoe" (or mistletoe), which
"draws its nourishment from certain trees, which has seeds that
must be transported by certain birds, and which has flowers with sep-
arate sexes absolutely requiring the agency of certain insects to bring
pollen from one flower to the other." It was "equally preposterous,"
Darwin concluded, "to account for the structure of this parasite,
with its relations to several distinct organic beings, by the effects of
external conditions, or of habit, or of the volition of the plant itself"
[Origin, 3).
Chapter 1: Cultivated Plants
Chapter 1, titled "Variation under Domestication," relied heavily on
examples from cultivated plants. Darwin focused at great length on
the interplay of two well-known aspects of the biology of plants: their
vegetative reproductive habits and their variability in different envi-
ronments. Variability was especially problematic. Darwin pointed
out that "seedlings from the same fruit and young of the same litter,
sometimes differ considerably from each other," though they have
had exactly the same conditions of life; but determining how much
of this variability to attribute to the direct action of the environment
was not easy. Darwin nonetheless maintained that "some slight
amount of change, may I think, be attributed to the direct action
of the conditions of life - as, in some cases, increased size from food,
colour from particular kinds of food and from light, and perhaps the
thickness of the fur from climate" [Origin, 10).
When seeking "laws of variation" or attempting to explain the
causes of such variation, Darwin acknowledged that they were
"quite unknown, or dimly seen," though he thought it worthwhile to
explore historical treatises on older cultivated plants like the potato,
the hyacinth, and the dahlia for what they revealed. He was surprised
especially by the "endless points in structure and constitution in
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which the varieties and subvarieties differ slightly from each other"
in these genera. This was especially striking to Darwin: "The whole
organization seems to have become plastic, and tends to depart in
some degree from that of the parental type" [Origin, 12). Darwin's
use of the word "plastic" to describe plant variation deserves special
notice, for it presaged the notion of plasticity in general and of pheno-
typic plasticity in particular, a phenomenon observed especially in
the plant world and understood only well after the 1920s and 1930s
(Smocovitis 1997). But Darwin, of course, knew little about the laws
of inheritance, let alone the distinction between genotype and phe-
notype; he expressed his frustration with the well-known remark
that the "laws governing inheritance are quite unknown" (Origin,
13). He simply stipulated that "any variation that is not inherited is
unimportant for us" [Origin, 12).
The chapter then turned to "man's selection," where Darwin
employed examples of human modification of animals and plants.
He considered "man's" ability to accumulate in organisms traits
useful to himself:
We cannot suppose that all the breeds were suddenly produced as perfect
and as useful as we now see them,- indeed, in several cases, we know that
this has not been their history. The key is man's power of accumulative
selection: nature gives successive variations,- man adds them up in certain
directions useful to him. In this sense he may be said to make for himself
useful breeds. [Origin, 30).
In this way Darwin stated that new forms have come into being,
summoning up Youatt's famous metaphor of "the magician's wand,
by means of which he may summon into life whatever form and
mould he pleases" [Origin, 3 1 ). As in the case of animals, new forms
of plants have so arisen; but in plants, the "variations are . . . more
often abrupt" [Origin, 32).
Plants also evinced a staggering diversity of parts within the same
species. While Darwin made allowances for "the laws of the corre-
lation of growth," he stated that "as a general rule, I cannot doubt
that the continued selection of slight variations either in the leaves,
the flowers, or the fruit, will produce races differing from each other
chiefly in these characters" [Origin, 33). He further added that the
horticulturalist, however, must have patience, since changes, even
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Darwin's Botany in the Origin of Species 221
in plants, can occur only slowly over many generations [Origin, 36).
Darwin concluded the chapter with the following closing thought:
"Over all these causes of Change, I am convinced that the accumu-
lative action of Selection, whether applied methodically and more
quickly, or unconsciously and more slowly, but more efficiently, is
by far the predominant Power" [Origin, 43).
Chapter 2: Importance of Data from Floras to the
Argument That Varieties Are Incipient Species
Plants figured most prominently, and were most important in lay-
ing out the argument for Darwin's theory, in Chapter 2, "Variation
under Nature." In this chapter, Darwin explored the nature and char-
acter of variation in the natural world. This is where he explored the
notion of individual differences and argued for continuous grada-
tions going from individual differences to varieties, incipient species,
and "good" species. Early on in the chapter, Darwin recognized the
puzzling phenomenon of "protean" or "polymorphic genera." These
were widely varying species with multiple forms of "inordinate vari-
ation" that were especially prevalent in plant genera like Rubus,
Rosa, and Hieracium (this last plant, known as the hawkweed, was
later to give Mendel a headache and possibly led him to drop his
experimental studies of inheritance in plants), as well as in some
insects and Brachiopod shells. For Darwin, these were "perplexing
cases" because they appeared to be polymorphic in all "countries"
and therefore seemed to vary independently of the conditions of life.
He wrote, "I am inclined to suspect that we see in these polymor-
phic genera variations in points of structure which are of no service
or disservice to the species, and which consequently have not been
seized on and rendered definite by natural selection, as hereafter
will be explained" [Origin, 46). The preponderance of polymorphic
genera in some large plant genera aside, Darwin drew heavily on
botanical data, notably from the huge number of flora that had been
compiled or were actively being compiled by systematic botanists.
That data, in Darwin's mind, was crucial in supporting his argument
that varieties are incipient species.
As Karen Parshall (1982) has shown, Darwin relied on mathemat-
ical calculations based on a series of floras compiled by botanists
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222 VASSILIKI BETTY SMOCOVITIS
like Joseph Hooker (and his flora of New Zealand), Asa Gray (and his
celebrated flora of temperate North America), Hewett C. Watson,
and others to lay the groundwork for his belief that varieties were
indeed incipient species (see also Browne 1980). From the summer
of 1 857 to the spring of 1 85 8, Darwin worked studiously on an enor-
mous compilation of botanical data that he then analyzed mathe-
matically. He knew that such use of numerical data to determine
relationships of genera, species, and varieties was actually fairly
common at the time: Alphonse de Candolle had compiled exten-
sive data in his Geographie biologique iaisonn.ee, and Asa Gray had
written "Statistics of the Flora of the Northern United States." 3
Though he was not mathematically inclined, Darwin was aware of
these studies and looked to them to provide numerical evidence of a
correlation between extensiveness of plant distribution and variabil-
ity. The larger the genus, the larger the species that it contained, or so
his theory suggested. 4
Darwin was of course famously vague about the definition of
'species,' writing on page 44: "No one definition has as yet sat-
isfied all naturalists: yet every naturalist knows vaguely what he
means when he speaks of a species. Generally the term includes the
unknown element of a distinct act of creation. The term 'variety'
is almost equally difficult to define; but here community of descent
is almost universally implied, though it can rarely be proved." He
held that "the term species, as one arbitrarily given for the sake of
convenience to a set of individuals closely resembling each other,
and that it does not essentially differ from the term variety, which
is given to less distinct and more fluctuating forms" [Origin, 52).
For Darwin, therefore, species did not differ in kind from varieties;
and while the naturalist's definition of species appeared "vague," it
served his purposes well: it supported his argument that that there
were no clear lines separating species from varieties or varieties from
individual differences. Taken as a whole, furthermore, such a view
3 Both had been recently published. See Alphonse de Candolle (1855) and Asa Gray
(1856-57).
4 There were three additional patterns possible: large genera having small species,
small genera having large species, and small genera having small species. Darwin
argued that the pattern of large genera having large species would be the likely
outcome if his theory were true.
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Darwin's Botany in the Origin of Species 223
also argued against the notion that species were the products of spe-
cial acts of creation.
To illustrate these points, Darwin wrote: "Guided by theoreti-
cal considerations, I thought that some interesting results might be
obtained in regard to the nature and relations of species which vary
most, by tabulating all the varieties in several well-worked floras"
( Origin, 53). He considered first what he termed "dominant species,"
or those that were at the same time the most widely diffused and
the most common in a particular geographical region. It was gener-
ally known that the most widely ranging species exhibited the most
varieties, but Darwin's use of available data in the context of his
theory took this point even further:
in any limited country, the species which are most common, that is abound
most in individuals, and the species which are most widely diffused within
their own country (and this is a different consideration from wide range, and
to a certain extent from commonness), often give rise to varieties sufficiently
well-marked to have been recorded in botanical works. Hence it is the most
flourishing, or, as they may be called, the dominant species, - those which
range widely over the world, are the most diffused in their own country,
and are the most numerous in individuals, - which oftenest produce well-
marked varieties, or, as I consider them, incipient species. [Origin, 53-4)
The data also indicated to Darwin that these "dominant species"
tended to belong to genera that were of proportionately larger size.
Based on his belief that species differed from varieties in degree
rather than in kind, Darwin finally conjectured that species in larger
genera presented more varieties than species in smaller genera, just
as he had postulated if his theory held true. And since his theory
held true, it could account for these phenomena better than any
creationist interpretation of species.
Chapter 3: Plants and the Struggle for Existence
Strangely enough, Darwin began this chapter, titled "Struggle for
Existence," stressing the relative unimportance of being able to dis-
tinguish the 300 or so species of British plants as species, subspecies,
or varieties [Origin, 60). Far more important to him was understand-
ing how species arise in nature and the process by which adap-
tation to the environment and to other interactions with species
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takes place. Critical to this process was the inevitable competi-
tion that took place in the "struggle for existence/' a phrase that
Darwin stressed was used in a "large and metaphorical sense, includ-
ing dependence on another, and including (which is more impor-
tant) not only the life of the individual, but success in leaving
progeny" [Origin, 62). Once again, Darwin referred to the "beautiful
co-adaptations" seen in the woodpecker and the mistletoe, but took
special care to use plants to make the point that such competition
is subtle as well as inordinately complex:
Two canine animals in a time of dearth, may be truly said to struggle with
each other which shall get food and live. But a plant on the edge of a desert is
said to struggle for life against the drought, though more properly it should
be dependent on the moisture. A plant which annually produces a thousand
seeds, of which on an average only one comes to maturity, may be more
truly said to struggle with the plants of the same and other kinds which
already clothe the ground. The missletoe is dependent on the apple and a
few other trees, but can only in a far-fetched sense be said to struggle with
these trees, for if too many of these parasites grow on the same tree, it will
languish and die. But several seedling missletoes, growing close together on
the same branch, may more truly be said to struggle with each other. As
the missletoe is disseminated by birds, its existence depends on birds; and
it may metaphorically be said to struggle with other fruit -bearing plants, in
order to tempt birds to devour and thus disseminate its seeds rather than
those of other plants. In these several senses, which pass into each other,
I use for convenience sake the general term struggle for existence. {Origin,
62)
Darwin thus painted an ornate picture of interactive relations among
organisms in nature; in the process of doing so, he also drew the dis-
tinction between interspecific and intraspecific competition, only
later formally recognized by twentieth- century ecologists. But the
plant examples he noted also served to give a more nuanced mean-
ing to his use of the metaphor "struggle for existence." As he noted,
plants could not rightly be said to struggle against drought, but only
against other similar plants; nor could they be properly said to "strug-
gle" at all, since that employed a kind of anthropomorphism diffi-
cult to uphold in the case of nonsentient organisms like plants.
The "convenient" metaphor of "struggle" was thus subject to crit-
ical interpretation; Darwin used it loosely to depict the frequently
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Darwin's Botany in the Origin of Species 225
unseen interactive forces at work in the natural world. Indeed, this
chapter as a whole, which was devoted to the complex relations of
living organisms, made especially notable use of such metaphors,
which later scholars from ecologists to literary critics have scruti-
nized (Beer 1983, 2000 revised edition). 5
The chapter also revealed Darwin's own clever experiments that
eventually inspired the field of plant ecology (Harper 1967). In one
critical experiment, Darwin followed the fate of native seedlings on
a cleared piece of ground three feet long by two feet wide. Out of 3 57
seedlings that germinated, 295 were destroyed by organisms like
slugs and insects. In yet another experiment on a little plot of turf
(three feet by four feet) that had been mowed for some time, he fol-
lowed the fate of plants allowed to grow freely without mowing and
grazing. Darwin found that under these conditions, the more vigor-
ous plants gradually killed the less vigorous plants, even though the
latter were fully grown. He counted some nine species that perished
as a result of competition from other species that were allowed to
grow freely. Such complex interactions were also seen as a result
of the enclosure of the heathlands, where Darwin had observed
a takeover by the Scotch fir tree. This was due to the protection
such enclosures afforded from grazing cattle. In yet other examples,
Darwin showed how insects were required for the existence of var-
ious plants such as orchids, which required visits from moths to
remove pollen masses for fertilization. He also noted yet another set
of experiments and observations he conducted on common red clover
pollination from humble-bees. 6 One of the most ecological chapters
of the Origin, it culminated with the famous description on page 74
of the "entangled bank." A metaphor for the complex relations
among diverse organisms, the entangled bank described by Darwin
was the result of a natural process that obeyed well-defined laws.
Thus, an image that appeared disordered or chaotic on the surface
5 The most famous of these evokes a disturbing image: "The face of Nature may
be compared to a yielding surface, with ten thousand sharp wedges packed close
together and driven inwards by incessant blows, some one wedge being struck, and
then another with greater force" [Origin, 67).
6 Darwin performed a series of experiments on the nectary structure and on various
flowers and insect pollinators that he published as brief articles or reports for the
Gardener's Chronicle in the 1850s.
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was in fact deeply structured, orderly, and emerged from well-defined
natural laws. Its importance not only to this chapter but also to
Darwin's thinking in the Origin overall is made apparent by its
appearance (though somewhat altered in form) in the final dramatic
paragraph closing the book.
Darwin concluded this important chapter by once again drawing
attention to the subtleness of competition in the plant world, in con-
trast to that of animals. Just as the structure of the teeth and talons
of the tiger served adaptive functions that enabled the animal to
compete, and just as the legs and claws of the parasite that clung to
the tiger's body enabled it to survive in a competitive world, so too
did the "beautifully plumed seed of the dandelion" have competi-
tive value [Origin, 77). With reference to such seeds, Darwin then
explained that in many plants the store of nutriment therein may at
"first sight" bear "no sort of relation to other plants." But then he
added: "from the strong growth of young plants produced from such
seeds (as peas and beans), when sown in the midst of long grasses,
I suspect the chief use of the nutriment is to favour the growth of
the young seedling whilst struggling with other plants growing vig-
orously all around" [Origin, 77). Darwin thus also understood the
nutritive value of seeds and their role in enabling the plants to sur-
vive in a competitive environment.
Chapter 4: Plants and Support for Natural Selection
Chapter 4 finally explored Darwin's "principle of natural selection,"
following the development of the argument laid out for it in Chap-
ters 1 to 3 . Darwin used plant examples in three important sections
of this chapter: (a) as illustrations of the action of natural selection;
(b) as examples of the intercrossing of individuals; and (c) as examples
demonstrating divergence of character.
imaginary illustrations. Darwin's best evidence in support of
his theory was indirect, based on an analogy with "man's selection"
and on the geographical distribution of plants and animals on conti-
nents and oceanic islands. He had no real direct evidence for natural
selection and instead relied in this section on two famously "imag-
inary illustrations." The first was the case of the predating wolf,
while the second, intended to be a more "complex" case, involved
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Darwin's Botany in the Origin of Species 227
the excretion by a plant of a sweet juice that would serve to draw
insects for pollination. In the latter example, Darwin devoted over
two pages of text to what was mostly a hypothetical discussion on
the origin of the complex parts of flowers coadapted as pollinating
mechanisms that would serve to enhance cross-fertilization of the
plants.
intercrossing of individuals. The elaborate mechanisms pro-
posed for cross-fertilization then gave way to a discussion of its
advantages. Here Darwin built on earlier insights on the subjects
of generation, reproduction, and sexuality, broadly construed [Note-
books, 170-71). For Darwin, sexual reproduction or intercrossing
between unlike individuals was potentially advantageous because it
was a means of increasing the variability of organisms. Such vari-
ability, alongside generation (which included not just birth but also
death), enabled the constant process of adjustment to the changing
conditions of life. The alternative mechanisms of vegetative (asex-
ual) reproduction and self-fertilization (inbreeding), though poten-
tially offering temporary advantages (such as enabling organisms
to colonize new habitats), limited variability and were in the long
term detrimental to organisms. Plants again offered stunning exam-
ples of diverse reproductive or mating systems that could serve as
examples for Darwin's theory; but what counted as "like" indi-
viduals, or what counted as proper, good, or true species, was not
easy to ascertain in the plant world, a problem long recognized, and
at times also capitalized on, by plant breeders. Indeed, hybridiza-
tion between "unlike forms," while serving to increase variabil-
ity, could also disrupt the integrity of species. Darwin was aware
of the complex issues raised by hybridization and reserved that
discussion for a later chapter devoted exclusively to the subject;
in the section on intercrossing, what he needed to show was the
advantages of intercrossing, meaning here mostly sexual reproduc-
tion. He therefore scoured the works of well-known plant breed-
ers like F. C. Gaertner and J. G. Koelreuter for their knowledge
and for relevant examples. He also drew extensively from C. C.
Sprengel's work on pollination mechanisms and floral anatomy to
engage in a substantive discussion of plant sexuality and the advan-
tages of intercrossing. He was also aware of the phenomenon of
hybrid vigour, which was later recognized by twentieth- century
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228 VASSILIKI BETTY SMOCOVITIS
geneticists as "heterosis," and used it to explain the advantages of
intercrossing:
In the first place, I have collected so large a body of facts, showing, in ac-
cordance with almost universal belief of breeders, that with animals and
plants a cross between different varieties, or between individuals of the same
variety but of another strain, gives vigour and fertility to the offspring; and
on the other hand, that close interbreeding diminishes vigour and fertility,-
that these facts alone incline me to believe that it is a general law of nature
(utterly ignorant though we be of the meaning of the law) that no organic
being self-fertilizes itself for an eternity of generations,- but that a cross
with another individual is occasionally - perhaps at very long intervals -
indispensable. [Origin, 96)
He also added to the store of knowledge from Sprengel his
own observations from experiments on Lobelia fulgens (on what
twentieth- century biologists call self-incompatibility) and his obser-
vations on a contrivance that prevents the stigma from receiving its
own pollen. In Lobelia, he wrote,
there is a really beautiful and elaborate contrivance by which every one
of the infinitely numerous pollen-granules are swept out of the co-joined
anthers of each flower, before the stigma of that individual flower is ready
to receive them,- and as this flower is never visited, at least in my garden, by
insects, it never sets a seed, though by placing pollen from one flower on the
stigma of another, I raised plenty of seedlings,- and whilst another species
of Lobelia growing close by, which is visited by bees, seeds freely. [Origin,
98).
Darwin then noted how varieties of various common vegetables
like cabbage, radish, onion, and other plants, if allowed to seed
near each other, will see "a large majority. . . of the seedlings thus
raised. . . turn out mongrels" [Origin, 99). This he confirmed with
his own data. Darwin attempted to understand the "mongreliza-
tion" of forms by conjecturing that pollen from another variety had
a prepotent effect over a flower's own pollen, but he then added that
"when distinct species are crossed the case is directly the reverse,
for a plant's own pollen is always prepotent over foreign pollen"
[Origin, 99). The flowers of many species, in Darwin's view, there-
fore had some kind of physiological or structural mechanism(s) in
place to ensure that they mated preferentially with their own kind
(for the most part, that is). While crosses served to increase variabil-
ity, they ideally also took place in way that ensured the integrity of
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Darwin's Botany in the Origin of Species 229
species. Darwin thus set the stage for his discussion of hybridization
or "hybridism," a phenomenon common in plants but that needed
explanation in the context of his theory.
divergence of character. By divergence of character, Darwin had
in mind a principle of "high importance" to his theory, the process
by which individual differences among members of the same species
gradually increase so as to form varieties, subspecies, and finally
distinct species. Simply stated, the principle was described thus:
"the more diversified the descendants from any one species become
in structure, constitution and habits, by so much will they be better
enabled to seize on many and widely diversified places in the polity
of nature, and so be enabled to increase in numbers" [Origin, 112).
Outlining the process was crucial to Darwin's theory as it explained
how species originated; he devoted some fifteen pages of the Origin
to the complex subject (see Kohn 2008 for extensive discussion of
this topic).
Plants once again figured prominently in Darwin's examples
demonstrating this important principle. He described a novel natural
experiment he had performed himself on turf plots three feet by four
feet in size that followed the diversification of the plants therein.
He wrote of his results: "it has been experimentally proved, that if a
plot of ground be sown with one species of grass, and a similar plot
be sown with several distinct genera of grasses, a greater number of
plants and a greater weight of herbage can thus be raised" [Origin,
113). So too under "natural circumstances" the "greatest amount of
life can be supported by great diversification of structure" [Origin,
114). Such natural circumstances included small ponds or islets or
limited environments where plant and animal inhabitants "jostled"
or competed with each other closely. Darwin further noted that
introduced or "naturalized" plants that were able to compete and
colonize successfully were often of a highly diversified nature, thus
presaging insights from the science of the biology of invasive species,
the area that is now known as "invasion biology" [Origin, 115).
Chapters 5, 6, and 7: Acclimatisation in Plants
In Chapter 5, titled "Laws of Variation," Darwin played on themes
referred to especially in Chapter 1, "Variation under Domestica-
tion." Only heritable variation was important for his theory, but
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230 VASSILIKI BETTY SMOCOVITIS
without detailed knowledge of the laws of inheritance, little could be
done to discern variation that was due to direct or indirect actions of
the environment (though Darwin did of course also think that direct
actions of the environment were often heritable). Darwin neverthe-
less thought it possible to "dimly catch a faint ray of light" [Origin,
132). He repeated his belief that the direct effect of the environ-
ment - a Lamarckian process - is extremely small in the case of ani-
mals but perhaps rather more pronounced in the case of plants. He
yet believed that often the direct effects of the environment would
be seized on by natural selection, and so preserved by his principal
device.
Chapter 8: Hybridism or Hybridization
Hybridization (and mechanical grafting) in plants was a time-
honored agricultural and horticultural practice. By the eighteenth
century, plant hybridization had drawn the attention of horticul-
turalists and practical breeders like Koelreuter and Gaertner, and
Darwin relied on their insights extensively in the Origin. Darwin
once again drew heavily on both for their understanding of hybridiza-
tion to support his view of the relations among varieties, incipient
species, and species. He especially needed to explain why species,
which, according to his theory, had descended from each other,
usually could not interbreed. Darwin offered a quick survey of the
diverse and complex patterns observed in the phenomenon of steril-
ity and its correlate, fertility in hybrids and mongrels (mongrels being
the progeny of varieties). He noted especially striking peculiarities
in hybridization patterns; species crossing with facility could give
rise to sterile hybrid progeny, while species that crossed with diffi-
culty could give rise to fertile hybrid progeny; and reciprocal crosses
between two species sometimes gave very different results. The view
that barriers to hybridization existed so as to "prevent confusion of
all organic forms," the standard explanation of why species did not
interbreed, was clearly not a viable explanation [Origin, 245). For
Darwin, the patterns of sterility and fertility observed instead pro-
vided further evidence in support of his theory and the view that
there were no clear lines between varieties, incipient species, and
species. It was also a way of arguing against special creation. He con-
cluded: "Finally, then, the facts briefly given in this chapter do not
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Darwin's Botany in the Origin of Species 231
seem to me opposed to, but even rather to support the view, that
there is no fundamental distinction between species and varieties"
[Origin, 278). This was to prove crucial in the penultimate chapter
on classification.
Chapters 11 and 12: The Geographical Distribution
of Plants
In keeping with his observations while aboard HMS Beagle, Darwin's
best evidence in support of his theory was drawn primarily from the
distribution patterns of the plants and animals he had observed while
he traveled on the celebrated voyage. The patterns - and the implied
relationships thereof - on continents and oceanic islands in partic-
ular inspired crucial reflection and provided evidence not so much
directly in support of his theory, but against the view that special
creation could account for the observable distribution and variation
patterns. Plants once again figured prominently in these chapters,
especially since the problem of dispersal and dissemination in plants
(using seeds or vegetative structures in reproduction) could be readily
tested even by gentleman naturalists. Here again, Darwin's experi-
mental efforts to test his theories of dispersal among continental
and oceanic forms of plant species figured prominently. He explored
what he termed "occasional means of distribution" through experi-
ments on seed survival during ocean dispersal. He tested 87 kinds of
plant seeds and found that 64 were able to germinate after an immer-
sion of 28 days in salt water, while a few survived 137 days. He
drew distinctions between small seeds (without capsules and fruit,
which could increase buoyancy as well as provide reserves) and veg-
etative structures like branches and leaves, performing experiments
that also took into account the rates of Atlantic currents, which he
found listed in Johnson's Physical Atlas. 7 He even tested the abil-
ity of seeds to survive and be transported above flotsam and jetsam
7 Darwin here was referring to a popular atlas by Alexander Keith Johnson that was
available at the time. "Johnson's Physical Atlas," as it was popularly known, had
been inspired by Alexander von Humboldt. Darwin may have used either the first
edition, which appeared in 1848, or the second, extended version, which appeared in
1 8 5 6; he may have also used both over a period of time. See Alexander Keith Johnson,
Physical Atlas of Natural Phenomena (London and Edinburgh: W. Blackwood and
Sons, 1848 edition and 1856 edition).
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232 VASSILIKI BETTY SMOCOVITIS
in the crops of pigeons and on the feet and in the beaks of birds.
He also took into account potential transport on icebergs and then
extended his discussion to include historic means of dispersal during
the glacial period. The discussion of the diverse means of transport
and the survivability of plants stretched to no less than twenty or so
pages of the Origin and revealed much about Darwin's experimental
prowess (see Bowler 2008).
Chapter 13: Classification, Morphology, and
Embryology in Plants
Plants make brief - but notable - appearances in Chapter 13 on
classification, morphology, and embryology. This was not so much
because plants were not important to these concerns, but because
Darwin had already given abundant evidence to support the argu-
ments of the chapter. By Chapter 13, the penultimate chapter,
Darwin had carefully built his argument for a rethinking of classifica-
tion based on a more natural plan that took into account community
of descent.
Darwin agreed with other systematists that vegetative structures
that varied greatly were not ideal characters for classification and
that reliance should instead be placed on the reproductive parts. He
wrote with some emphasis: "organs of vegetation, on which their
whole life depends, are of little signification, excepting in the first
main divisions; whereas the organs of reproduction, with their prod-
ucts the seed are of paramount importance!" [Origin, 41 4). 8 In this
statement Darwin also revealed an insight from what is now known
as "plant developmental biology," which he later developed on pages
418-19. By speaking of "main divisions" Darwin recognized the pro-
cess by which the fundamental character used in the major division
of plants into the Dicots and the Monocots originated embryonically.
He wrote:
The same fact holds good with flowering plants, of which the two main
divisions have been founded on characters derived from the embryo, - on
8 Darwin had earlier resisted this idea but changed his mind because his theory of
descent upheld the view that essential parts (or characters) were common in related
groups. These were therefore the least likely to vary.
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Darwin's Botany in the Origin of Species 233
the number and position of the embryonic leaves, or cotyledons, and on
the mode of development of the plumule and radicle. In our discussion on
embryology, we shall see why such characters are so valuable, on the view
of classification tacitly including the idea of descent. [Origin, 436)
He also recognized yet another significant fact of plant develop-
ment that was most closely associated with German morphologists
like Johann Wolfgang von Goethe:
It is familiar to almost every one, that in a flower the relative position of
the sepals, petals, stamens and pistils, as well as their intimate structure,
are intelligible on the view that they consist of metamorphosed leaves,
arranged in a spire. In monstrous plants, we often get direct evidence of the
possibility of one organ being transformed into another,- and we can actually
see in embryonic crustaceans and in many other animals, and in flowers,
that organs, which when mature become extremely different, are at an early
stage of growth exactly alike.
This latter point was especially important because it suggested reca-
pitulation, which was a demonstration of descent. Darwin then
resumed his reverse argument in support of his theory, and against
special creation, to account for this; he also demonstrated the taxo-
nomic promiscuity and the comparative rhythm that characterized
his style of argumentation in the Origin overall:
How inexplicable are these facts on the ordinary view of creation! Why
should the brain be enclosed in a box composed of such numerous and such
extraordinarily shaped pieces of bone? As Owen has remarked, the benefit
derived from the yielding of the separated pieces in the act of parturition
of mammals, will by no means explain the same construction in the skulls
of birds. Why should similar bones have been created in the formation of
the wing and leg of a bat, used as they are for such totally different pur-
poses? Why should one crustacean, which has an extremely complex mouth
formed of many parts, consequently always have fewer legs; or conversely,
those with many legs have simpler mouths? Why should the sepals, petals,
stamens and pistils in any individual flower, though fitted for such widely
different purposes, be all constructed on the same pattern? [Origin, 437)
The answer to all of these questions is that the mentioned structures
have been derived from common descent.
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234 VASSILIKI BETTY SMOCOVITIS
CONCLUSIONS
What if any general conclusions can we draw from this brief study of
Darwin's botany in the Origin 2 . For one thing, plants were absolutely
foundational to the development of his argument. Plant examples
appear in greatest abundance throughout Chapters i to 4, the criti-
cal chapters laying out the argument for his theory and especially
in Chapter 2, where Darwin used botanical data in support of his
argument that varieties may be seen as incipient species. Darwin's
use of hybridization in Chapter 8 played a similar foundational role
in establishing varieties as incipient species; it also supported his
natural or genealogical (or what we now term "evolutionary") clas-
sification.
Yet another conclusion we may draw is that Darwin's own re-
searches into botany deserve more credit than has been given him.
Historians have always known that botany figured prominently in
his work after the Origin, but have not fully appreciated the extent
to which the study of plants served a foundational role in formulat-
ing the argument for his theory. As one recent study has revealed,
historians still have much to learn about the early influences that
teachers like Henslow had upon Darwin (Kohn et al. 2005 ).
Along these lines, historians have also not fully appreciated
Darwin's adroitness in the use of experimentation (though his pow-
ers of observation have been duly noted and appreciated). A closer
reading of Darwin's botanical research in the Origin reveals the
extent to which he was engaged in clever and crucial experiments
to test or buttress key points of his theory well before i860. Study
of Darwin's botany also reveals the more practical, "down-to-earth"
aspects of his work, which complements the traditional historical
portrait of Darwin as a great theorist and synthesizer (he was, of
course, but this was possible because he was also a keen observer
and experimentalist).
Taking this point a bit further, historians might wonder why Dar-
win did not consider himself a botanist, and why botanists did not
readily claim him as one of their own, given that it was the one
area of natural history where he arguably made the most notable
contributions. One reason for this is that his proximity to full-time
systematists like Hooker and even Gray (who were entirely devoted
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Darwin's Botany in the Origin of Species 235
to the systematic study of plants) may have thwarted his identi-
fication as a botanist. Compared to them, and other like-minded
specialists, Darwin lacked the kind of single-minded devotion to
one particular taxonomic group. Yet another reason may be that his
experiments lacked the kind of laboratory setting that was increas-
ingly taking center stage in botanical practice as it embraced the
"new botany" associated with microscopy and table-top instrumen-
tation. In at least one celebrated exchange with the noted German
plant physiologist and experimentalist Julius Von Sachs, Darwin was
criticized, if not belittled, for his lack of experimental rigor (Heslop-
Harrison 1979; De Chadarevian 1996). Caught between the full-time
systematists, whose botanical knowledge of individual groups was
incomparably greater than Darwin's, and the proponents of the "new
botany," whose experimental methods appeared to be more rigorous,
Darwin's contributions to botany resided in a peculiar place that did
not gain real status or legitimacy until the second half of the twen-
tieth century, with the emergence of the new field known as "plant
evolutionary biology." Even his contributions to the area of "evolu-
tionary ecology" or "plant ecology," areas that were clearly articu-
lated in the Origin, had to wait until those fields came to fruition
in the latter half of the twentieth century. His equally keen insights
into the biology of invasive species and his contributions to the new
field of "invasion biology" have been recognized only in recent years
(Hayden and White 2003).
Plant evolutionary biology itself did not properly come of age
until the 1930s and the 1940s, during the period of the "evolution-
ary synthesis." It was during this period that Darwinian evolutionary
understanding was integrated with Mendelian genetics in a manner
that could account for the origin of biological diversity. A num-
ber of questions and problems that Darwin had encountered were
resolved by this integration of heredity and evolution, broadly con-
strued. For plant evolution more specifically, this integration took
place in 1950 with the publication of G. Ledyard Stebbins's Varia-
tion and Evolution in Plants-, it was only after this synthesis that
many of the phenomena that had piqued Darwin's interest but that
had bedeviled him and his contemporaries interested in formulat-
ing a general theory of plant evolution were resolved, or at least
re-problematized (see Arnold 1997 for new views on hybridization
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236 VASSILIKI BETTY SMOCOVITIS
and evolution). Thus, Darwin's botanical efforts did not really come
to fruition until enough was understood about the evolutionary biol-
ogy of plants; just the same, in the context of their day and in the
context of the Origin, Darwin's insights into plant evolution proved
to be critical to formulating the most coherent theory then available
for general evolution.
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DAVID J. DEPEW
13 The Rhetoric of the Origin
of Species
I. THE ORIGIN AS RHETORICAL ARGUMENTATION
In 1828, the Oxford don Richard Whately, having in his Elements of
Logic (1826) defined argument as the connection between a claim and
its support, proposed in its newly published counterpart, Elements
of Rhetoric, to
treat argumentative composition as a species of rhetoric. . . . The office of
the logician is to infer, but the office of the rhetorician is to advocate by
adducing proofs. . . . Thus even the philosopher who undertakes by writing
or speaking to convey his notion to others assumes for the time being the
character of advocate of the doctrines he maintains. (Whately 1963, 5)
The idea that rhetoric is situated argumentation - argumentation
giving reasons why a specific audience should come to the speaker's
side of a disputed issue or controversial topic - is old. Aristotle
took this line when he defined rhetoric as the "ability to discover
the available means of persuasion in each particular case" [Rhetoric
I.2.i3 5 5b27-8). The idea still has champions (Toulmin 2003). This
argument- centered conception of rhetoric contrasts sharply with the
equally ancient view that the specific task of a rhetor is not to find
or set out an argument but skillfully to deck one out with whatever
ornaments of speech might induce a presumably less-than-rational
audience to be affected, even infected, by it. Scientists and philoso-
phers assume just such a conception when they hold that logically
valid, context-free, undecorated arguments are the only sort that
count. Whately's view also contrasts, however, albeit less severely,
with a third conception of rhetoric. Emerging in the eighteenth
237
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238 DAVID J. DEPEW
century, I will call it the expressive view and will explicate it by
citing Charles Darwin's Journal of Researches.
The title page and first line of the Origin of Species identify its
author as the Charles Darwin who in 1 8 3 9 began to publish his obser-
vations as a naturalist onboard HMS Beagle in an engaging travel
narrative that at times displayed the visual vivacity first demanded
of British writers by the influential eighteenth- century critic and
essayist Joseph Addison. More particularly, the style of Darwin's
Journal of Researches reflects the Romantic Zeitgeist that he had
imbibed from the youth culture of his day, with its Wordsworthian
conviction that words can be as vivid as pictures only if they arise
from the overflow of powerful emotions into an expressive medium.
Writers who embraced this ideal seldom acknowledged models; fol-
lowing models was generally taken to be slavishly imitative. In point
of fact, however, Darwin's travel narrative did have a model for its
use of emotional experience and language as a way of penetrating
nature's secrets and enlisting the sympathy of its readers. Alexan-
der von Humboldt's Personal Narrative affected both the substance
and the style of Darwin's Romantic naturalism (Manier 1978; Kohn
1996; Richards 2002; Sloan 2005).
A case can be made that the Origin is just as expressive as the
Journal of Researches. Readers of Darwin's Origin can hardly miss
its author's personal warmth, ethical sensibility, and capacity for
wonder (Levine 2006). Nonetheless, the "I" who in the first line
establishes his credentials by referring to his voyage on the Beagle
is not quite the same as the "I" of the earlier book. To be sure,
the attractive character of the speaker (what rhetorical scholars call
ethos) is still designed to elicit in his readers a well-disposed affective
state [pathos) that will open them to what he has to say. But this time
the speaker is painfully anxious to secure the good will of readers
whom he assumes are as skeptical as he once had been about claims
that made Victorian Britons pretty nervous. The Origin's readers
are asked to abandon strong prejudices that had been built up by
the British press and clergy ever since the decidedly French idea of
species mutability had begun to circulate in the 1820s. They are to
do so by constructing, through the act of reading, a counterpart of
their real selves who will be responsive to the speaker's appeal to
their ability to reason, to assess evidence fairly, to enter into the
spirit of imaginative thought experiments, and who exhibits other
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The Rhetoric of the Origin of Species 239
flattering traits. Expressive as it sometimes is, the Origin's rhetoric
is unmistakably situated argumentation in Whately's sense.
Consider that in its recapitulative last chapter the speaker refers
reflexively to the text itself as "one long argument." This means that
it is not, or not primarily, a narrative [Origin, 459; Secord 2000, 510).
Initially, this disconcerted even so discriminating a connoisseur of
fine arguments as George Eliot, who in the course of informing a cor-
respondent in December 1859 that sne an d her partner, George Henry
Lewes, had begun reading Darwin's book wrote: "It expresses thor-
ough adhesion, after long years of study, to the Doctrine of Devel-
opment. The book is ill written and sadly wanting in illustrative
facts. . . . This will prevent it from becoming popular, as the Vestiges
did" (quoted in Secord 2000, 512-13; Beer 2000, 146).
George Eliot apparently expected her evolutionary reading to spin
out grand narratives stretching from the nebular formation of the
universe to the imminent reduction of psychology to brain science,
as popular-science audiences often still do. She expected the Origin
to be as satisfying to the imagination as the sensational Vestiges
of Creation, which had appeared anonymously in 1844 and was
later shown to have been written by the skilled journalist Robert
Chambers (Secord 2000). The phrase "Doctrine of Development"
suggests that Eliot also expected the Origin to repeat much the
same evolutionary story that Lamarck, Chambers, and her friend
Herbert Spencer were telling, a tale of inevitable complexification
and progress (Beer 2000, 146). She did not know that the trashing
of Vestiges by people whose opinions he valued had led Darwin to
search for arguments that would not be vulnerable to the criticisms
leveled against Chambers and, when at last he made these arguments
public, to couch them in a decidedly unsensational way. Accordingly,
although I make no case for Whately's influence on Darwin, I will
focus in this chapter on the argumentative rhetoric of the Origin.
Darwin's use of metaphor will come into the question, to be sure,
but as serving argumentative purposes.
In order to highlight these purposes, I will make use of the dis-
tinction between real and textual speakers and audiences that I have
already been drawing. In spite of the fact that it will at times seem
clumsy and artificial, this distinction offers a useful analytic tool.
In the last several decades, Darwin scholars have brought a range
of influences to bear on interpreting the Origin and Darwin's other
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240 DAVID J. DEPEW
works. But not everything that went into the making of Charles
Darwin necessarily went directly into the making of the "I" of the
Origin. This voice serves to filter, transform, muffle, or even disguise
whatever might be found unpersuasive to the implied audience.
What about that audience? Darwin's actual readers did not simply
disappear into the textual construct that had been designed to attract
them. They wrote back, creating a feedback loop between Darwin
and his audience. This was possible because of the rapid expansion
of the Victorian post and press at the time (Young 1985, 153). In
his empirical study of the Origin's reception, Alvar Ellegard counted
reviews in no less than 155 newspapers, magazines, and quarterlies
(Ellegard 1958, 369-84). Darwin's letters show him taking anxious
note of most of these, as well as of numerous foreign reviews, regis-
tering in each case how far the reviewer "goes with me" and some-
times writing to thank this one or that one for going as far as he did.
Replies, refutations, rebuttals, and concessions are obsessed about,
debated with correspondents, and handed over to the speaker for
inclusion in subsequent editions. In the process, the speaker's voice
becomes overlaid with Darwin's bobbing and weaving defense. Per-
haps these complications are partly responsible for recent tendencies
to think of editions other than the first as a fall from scientific, philo-
sophical, or literary grace. In some ways they are. But the intense
feedback between the real Darwin and his real audience means that
the Origin is not reducible either to its author's intentions or to the
history of its reception. It is a temporally extended process of discur-
sive interaction located in and responding to a constantly shifting
rhetorical situation largely of its own making.
II. ONE LONG (RHETORICAL) ARGUMENT
Darwin's preferred scientific methodology demarcated inductive sci-
ence from the mere hypothesizing that he and many other critics saw
in Vestiges by requiring causes to have real existence in nature prior
to exhibitions of their explanatory elegance, parsimony, or fecundity.
This so-called vera causa (real cause) ideal dictated that Darwin's
positive case for common descent driven by natural selection would
have a three-part exposition. It would move from arguing for the
existence of natural selection, to its competence to account for com-
mon descent, to showing, finally, how beautifully common descent
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The Rhetoric of the Origin of Species 241
through natural selection can integrate up-to-date results in biology
and how elegantly it can resolve its most disputed issues (Hodge
1977). At every point in this process, however, the solicitous "I"
who does the arguing pits his evidence for descent with modification
through natural selection against what he repeatedly calls "the ordi-
nary doctrine of creation." The Origin's "I" denies that new species
arise by way of instantaneous acts of creation through non-natural
means. He denies, too, that instances of such acts may be found here
and there or now and again. Rather, species arise only once at a single
geographical point of origin. They gradually depart by way of normal
reproduction and natural selection from varieties of existing species
and are dispersed across time and space by causes no less natural. All
higher taxa emerge by protraction of the same process. Accordingly,
the speaker directly contravenes the Cambridge polymath William
Whewell's claim that "Nothing has been pointed out in the exist-
ing order of things which has any analogy or resemblance of any
valid kind to that creative energy which must be exerted in the pro-
duction of new species" (Whewell 1840). The Origin's "I" contends
that a real cause observable in the existing order does indeed bear
such a valid analogy - natural selection. Commentators from Dar-
win's American friend Asa Gray to the late Stephen Jay Gould have
pointed out, usually with relief, that this claim is logically compati-
ble with a range of religious beliefs (Brooke, this volume). But by the
lights of Darwin's day, special creation was a scientific, not a the-
ological or Biblical, claim. And by these lights it was flatly incom-
patible with common descent by natural selection. The Origin's
"I" acknowledges this contradiction by arguing from start to finish
against "the ordinary doctrine of creation."
Darwin probably had particular people in mind in framing his
anti-creationist argument: his mentors in natural history, especially
those who had slammed Vestiges-, the professional colleagues to
whom he was promising something more than the "abstract" they
would soon be reading [Origin, 1); his wife, Emma, whose sensitiv-
ity on the subject of religion had long served as an internal check
on his intimations of disbelief and who in consequence "became
Darwin's model of the conventional Victorian reader" (Kohn 1989,
226). But these and other individuals, as well as the anonymous
audience that Alfred Russel Wallace dubbed "the general natural-
ist public" [Correspondence, 14: 227), were all addressed by means
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242, DAVID J. DEPEW
of the internally conscripted audience with which they were asked
to identify. As early as the first sentence, this audience is called
"we" (Beer 2000, 60). "We" are close observers of the living world.
"We" see, for example, that domesticated plants and animals vary
more than those "in a state of nature" [Origin, 7). Increasingly, "we"
become reflective about how to explain this and other phenomena
that the speaker reports. Being reflective, "we" diligently follow his
exposition. "We" are asked to bear with him as he proceeds further
(Origin, 59). When he summarizes points already covered, the "I"
becomes one of the "we" himself: "We have also seen that the most
flourishing and dominant species of the larger genera on an average
vary most" ( Origin, 59).
The Origin's "we" are not assumed to be members of an elite
community of professional naturalists. On the contrary, although
the speaker is clearly one of them, he sometimes refers in the third
person to "naturalists" as holding this or that view [Origin, 44-
7, 413, 469, for instance). This slight objectification of the scientific
community explains several of the text's most subtle rhetorical qual-
ities. His peers, once conscripted as readers, are asked to judge the
issue as if they were overhearing an argument addressed to an open-
minded but nonexpert third party, thereby prying these experts away
from claims they might otherwise dismiss out of hand by virtue of
their professional identities. By the same token, the general public
becomes Wallace's "general naturalist public" by being invited to
judge a scientific issue. Early in 1 860, a correspondent of Emma Dar-
win reported that she had overheard someone asking for the Origin
at a bookstall in a railway station, only to be told that it was sold out
[Correspondence, 8: 35). The notion that the Origin was only acci-
dentally taken up by a diverse reading public is, I think, exaggerated.
The book opens itself to the public. This fact also helps explain the
feeling of some professional naturalists that the Origin displayed an
antiquated character (Ruse, this volume). In the decades since Dar-
win had begun secretly writing about the mutability of species, biol-
ogists had taken a turn toward continental structural morphology
and away from Paley's functionalist, utilitarian view of biological
traits. But British naturalists had so deeply implanted in the public
mind the idea that traits are intentionally designed for specific pur-
poses that they were compelled to remain decorously faithful to it,
even while the best of them, such as Richard Owen, were furtively
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The Rhetoric of the Origin of Species 243
searching for ways to split the difference. By taking seriously an out-
dated but revered view, the Origin had the effect of removing an
obstruction to the flow of scientific discourse.
Why, we may ask, was the book addressed to "the general natu-
ralist public" at all? It was, I think, the fact of having to intervene in
the delicate rhetorical situation created by receipt of Wallace's paper
that made the Origin a rhetorical performance on a public stage. This
situation also turned the impressive body of inductive evidence that
Darwin had collected in his "big species book" into an inventory
of examples. Aristotle says that the rhetorical counterpart of induc-
tion is the telling example [Rhetoric I.2.i3 56b2-5). The exemplary
status of Darwin's factual evidence implies an incompleteness that
the speaker acknowledges, even exaggerates, at the outset [Origin,
2). Incompleteness in turn places weight on the inferential aspects of
the "one long argument." These include, in addition to exhibitions of
hypothetical-deductive reasoning and thought experimenting, spon-
taneously generated forms of rhetorical argumentation well known
to rhetoricians since antiquity, all of which are aimed at loosening
and then reversing the initial presumption in favor of special creation
imputed to the text's implied audience.
One of these figures is the use of reductio ad absurdum as ridicule.
We can see it at work in the three passages in which the phrase vera
causa actually occurs. In all three, the phrase is set in polemical
opposition to "the ordinary doctrine of creation," which the speaker
takes to be no true cause at all. "The ordinary doctrine" appeals to
miracles when perfectly good natural means of generation and dis-
persal are right in front of our eyes [Origin, 352). It inconsistently
appeals to natural or "secondary causes" in the case of varieties but
"arbitrarily rejects them" when it comes to species [Origin, 482).
It trivializes the Deity by attributing the slightly different stems
of three species of the lowly turnip to "three separate acts of cre-
ation" that are too closely related for any supreme being other than
a perverse micromanager to bother with [Origin, 159).
By their nature, appeals to the absurdity of an opposing claim
exude contempt. This is not the best way to court the good will
of an audience. Thus it is unsurprising that the solicitous "I" uses
it sparingly. By contrast, advancing one's argument by anticipating
and allaying an audience's objections, the emotional counterpart of
which is sympathetic identification with their difficulties, pervades
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244 DAVID J. DEPEW
the Origin. 1 From start to finish the speaker interrupts his exposi-
tion to put himself in the reader's place. He not only raises important
objections but puts the case for each so strongly that he seems to
take his readers' worries on himself. He does this in the expectation
that the reader, having been painted as intelligent and dispassionate
enough to raise such intelligent objections, will reciprocate by treat-
ing his answers to these objections as no less intelligent and, by this
route, will eventually come around to his own painfully acquired
view that the burden of proof should be shifted onto the "ordinary
doctrine." This dimension of the Origin's "one long argument" was
noticed by its first anonymous reader, a friend of the publisher who
had been asked to assess the manuscript. "Mr. Darwin," he reported,
"has brilliantly surmounted the formidable obstacles which he was
honest enough to put in his own path" (see Browne 2002, 75 ).
So deeply is the argument of the Origin structured by the strat-
egy of anticipated objection and response that the three stages by
which it seeks to meet the vera causa ideal - the existence, com-
petence, and responsibility of natural selection - are marked off by
episodes in which objections are raised and allayed. In the Introduc-
tion, the speaker concedes that he is "well aware that scarcely a
single point is discussed in this volume on which facts cannot be
adduced often apparently leading to conclusions directly opposite to
those at which I have arrived" (Origin, 2). The case for competence
proceeds throughout by refuting a "crowd of difficulties" first raised
in Chapter 6. The most pressing difficulties are the absence of inter-
mediates in the fossil record; the perceived implausibility of natural
selection's power to evolve "organs of extreme perfection" like the
eye; similar doubts about instincts such as the wonderful behavior
of the bee and the slave-making behavior of certain ant species; and
the sterility of hybrids, which seems to firm up species boundaries
and to be of no use to individuals [Origin, 17 1-2). Chapter 6 itself
rebuts the first two objections, although the speaker returns to the
first in Chapter 9. Separate chapters are then devoted to the third and
fourth objections. All this clears way for three chapters in which the
theory's explanatory fecundity is set out positively. The recapitula-
tive Chapter 1 4 promises a summary, but first launches into yet one
1 The Greek rhetorical term for anticipating objections is prolepsis or more specifi-
cally piokatalepsis.
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The Rhetoric of the Origin of Species 245
more run through the objections [Origin, 469). In contrast to most
addressed arguments, then, which typically leave begrudging room
for replies to a few objections at the end, it is fair to say that the
Origin is pervasively structured by anticipation of and response to
objections.
This anticipatory structure contributes not only to the division
of the "one long argument" but to its unity as well. By the end,
the speaker's good will has brought into existence a reader to match.
Moving toward his peroration, he at last explicitly asks this reader to
concur that special creation seems highly improbable [Origin, 471).
Only at this point does he overtly place responsibility for failure
to look at the massive evidence for species mutability on "a load of
prejudice" and "the blindness of preconceived opinion" ( Origin, 482-
3). Disciples of Bacon could easily be shamed for having worshipped
such idols. But to have raised this charge earlier would have undercut
the speaker's claim that the objections are indeed serious and that he
is taking them seriously. The audience is now construed, however,
as having come far enough with the speaker to cast off its blinkers
and let the full weight of his case sink in. The rhetorical argument
is thus the matrix within which the reader is invited to embrace the
scientific argument as a grounded conclusion. Questions have been
raised about just how unified the "one long argument" actually is
(Waters 2003). They will persist, I think, as long as the rhetorical arc
that textually constructs that unity is discounted.
III. PRESUMPTION, BURDEN OF PROOF, AND
THE ORIGIN'S NATURAL THEODICY
In opposing special creation, Darwin shrewdly avoided Lyell's mis-
take in Principles of Geology of so fully instructing his readers in
Lamarck's evolutionary theory that it intrigued rather than, as Lyell
had intended, horrified them. 2 Even without the speaker explicating
its strong points, however, "the ordinary doctrine" had a good deal
going for it, especially when matched against the Origin's alterna-
tive. There were those missing fossil intermediates. Moreover, the
same species were found in geographically discontinuous places. So
Darwin's claim of their original contiguity had to rely on hypotheses
2 I owe this point to Robert Richards.
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246 DAVID J. DEPEW
about warming climates leaving species stranded on mountaintops
that became islands and the dispersal of seeds by wind, waves, or in
the beaks of birds, bolstered by some backyard experiments [Origin,
358). When direct evidence is missing, suspicions, not just difficul-
ties and objections, easily arise. The speaker's way of dealing with
them is to use the goodwill accumulated by his anticipatory rhetoric
to shift the burden of proof onto special creation.
The Origin's readers could be assumed to be familiar with and
responsive to the strategy of securing consent to one side of a con-
tradiction by pushing the burden of proof onto the other. This figure
of argument had long been common in British public discourse, and
not just in the legal sphere in which it still operates. British dis-
course generally was, and still is, a posteriori in spirit and, in matters
not open to demonstration, appealed to standards no more (or less)
strenuous than probability, moral certainty, common sense, and, not
least, presumption. A presumption, wrote Whately, is not exactly
a probability. "It is a pre-occupation of the ground . . . that must
stand good till sufficient reason is adduced against it. . . . The bur-
den of proof lies on the side of him who would dispute it" (Whately
1963, 112). Shift the burden, and the presumption moves to your
side.
Since the end of the seventeenth century, this way of arguing
had played an important role in portraying the modern British state
to itself as a moderate, reasonable regime coordinating a moderate,
reasonable people. Its moderation was exhibited, first, by the impor-
tance its intellectuals accorded to natural theology, which estab-
lished the existence, power, and providence of God by way of evi-
dence about the functional order of the universe that all could see.
On the foundation of this "argument from design" was erected a
moderate interpretation of revealed truth that pushed both Puritan
"enthusiasm" (too much revelation) and tepid deism (too much nat-
ural theology) to the margins, in part by drawing a line between
superstitions and the miracles credibly testified to by the New Tes-
tament writers (Butler 1961, 150). If Jesus had not turned loaves into
fishes for five thousand, surely someone would have testified against
it. But that hadn't happened. Hence the presumption that a miracle
had taken place stood. Not only the observably functional order of
nature, then, but credited miracles that occasionally violated that
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The Rhetoric of the Origin of Species 247
order counted as traces [vestigia) of the presence of a personal, car-
ing God in His lawfully ordered world. Accordingly, in the most
revered apologetic work of the eighteenth century Joseph Butler's
Analogy of Religion, we read, "I find no appearance of a presumption
from the analogy of nature against the general scheme of Christian-
ity that God created and invisibly governs the world. . . . There is
no presumption against the operation which we should now call
miraculous" (Butler 1961, 144-5).
Special creation was "science in a theistic context" (Brooke et al.
2001 ) because it made sense against the background of a lawful natu-
ral order occasionally interrupted by divine interventions. Both "the
ordinary doctrine of creation" and the background that legitimated
it - what the rhetorical scholar John Angus Campbell called Britain's
"grammar of culture" and the historian of science Robert Young
dubbed its "common context" (Campbell 1986; Young 1985) - had
the force of standing presumptions that could be challenged only
by accepting high burdens of proof and the real possibility that, in
failing to meet those burdens, one's reputation as sound in mind and
character might be damaged. In the middle of the eighteenth century,
David Hume accepted the challenge with his double-barreled assault
on natural theology and the very possibility of miracles. His repu-
tation suffered accordingly, but in the end his effrontery served as
little more than an occasion for reaffirming the cultural grammar's
commonplaces.
To be sure, signs of weakness were showing in the secularizing
era of the Reform Bill in which Darwin came of intellectual age.
Biblical criticism began to push even New Testament miracles into
the territory of faith alone, and in the Bridgewater Treatises, six
volumes commissioned in the early 1830s to buff up natural theol-
ogy in the light of up-to-date science, arguments from probability
and presumption that had been developed to defend the reasonable-
ness of revelation and credited miracles were now being used to
prop up the design inference itself. How improbable that so many
physical and chemical processes would coincide in just the right
way at just the right time to make a functioning eye or, out of cos-
mic gases, a planetary system that led to our life on Earth (Chalmers
1833, 13-16; Whewell 1833, 29). So the old presumptions stood. Still,
Butler's confidence that presumption was enough to justify assent
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248 DAVID J. DEPEW
was coming under pressure from the more empirically demanding
scientists. It is telling that Whately, who had started his career by
defending miracles as no less worthy of belief than the existence
of Napoleon Bonaparte - both were based on testimony - made
the management of presumption and burden shifting the keystone
of Elements of Rhetoric (Whately 1961, 112-32). He was shoring
up rhetorical norms of argumentation in a situation of perceived
danger.
Nothing could more precisely express the burden taken up by the
Origin's "I" than Whately's assertion that if a rhetor wishes to shift
the burden of proof onto a standing presumption, he must take pains
to "enable men to see the improbability and sometimes utter impos-
sibility of what at first glance they will be apt to regard as perfectly
natural" (Whately 1963, 51). From his youth, Darwin had been both
immersed in the discursive practices of the cultural grammar and
skeptically reflective about them. As a result, he was fully aware
that British natural theology was a sublime object of ideology and
that "the ordinary doctrine of creation" seemed ordinary because it
was deeply embedded within that ideology. Vestiges had proclaimed
that evolution is simply another secondary cause, like gravity, by
which God carries out his creative work. His mentors' doubts about
how well Chambers had carried this point had taught Darwin that
in defending his alternative he should appeal as substantively as
possible to the commonplaces and values with which the "ordinary
doctrine" had been defended. His strategy was to use the goodwill
accrued by anticipating objections to turn the most sacred assump-
tions of the cultural grammar against what seemed "at first glance
perfectly natural" in their light.
The Origin's treatment of the eye shows this strategy at its most
acrobatic. Like Paley and the Bridgewater authors, the speaker takes
the eye as the paradigmatic example of an "organ of perfection so
extreme and complicated" that seemingly only a god could have
made it [Origin, 86). In attempting to undermine the assumed natu-
ralness of this inference, the speaker produces a thought experiment
about how selection might conceivably have worked gradually from
small bits of light-sensitive tissue to make an eye. He concludes,
"We should be extremely cautious in concluding that [such an] organ
could not have been formed by transitional gradations of some kind"
[Origin, 190). Readers of the Origin may have taken this argument
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The Rhetoric of the Origin of Species 249
not as a question-begging sophism, but as a delicate, decorous appeal
to standards with which they were familiar and by which they were
capable of being moved. Why? Because its actual warrant is not, in
fact, the thin thought experiment about light-sensitive tissue, but
rather, as the text makes clear, the supposition that natural selec-
tion is a power "always intently watching each slight accidental
alteration in the transparent layers [of tissue] and carefully selecting
each alternative which, under various circumstances, may in any
way or in any degree tend to produce a distincter image" [Origin,
189). Here we discover natural selection as a creative power rivaling
in goodness the God of Britain's cultural grammar.
The Origin's textual antecedents reveal steady development of the
image of natural selection as a beneficent scrutinizer from its first
occurrence in 1842, where the selector is a personal, if hypothetical,
agent, to the Origin's treatment of natural selection as an agency
or natural power defined entirely by its effects (Sloan 2001, 262-5).
This agency is far more oriented to the good of each organism than
human breeders:
Man can act only on external and visible characters. Nature . . . can act on
every internal organ, on every shade of constitutional difference. . . . Man
selects only for his own good, Nature only for that of the being which
she tends. . . . How fleeting are the wishes and efforts of man! How short his
time! And consequently how poor will his products be, compared with those
accumulated by nature during whole geological periods .... Daily and hourly
natural selection is scrutinizing, throughout the world, every variation, even
the slightest, rejecting that which is bad, preserving and adding up all that
is good. [Origin, 83-4)
Echoes of the biblical sublime in this passage have the effect of
refiguring the Origin's examples. From metonymic (parts standing
for wholes) surrogates for the elided full range of inductive evidence,
every adaptation is turned into a synecdoche (a part as a concentrated
expression of a whole) proclaiming that natural selection cares com-
pletely and exclusively for the good of "every being." A "natural
theodicy" is at work here. Traditional British theism had figured
the Creator as, at best, a cost-benefit maximizer and at worst as
making sport of his own creation, as Shakespeare's King Lear at
its most nihilistic suspects. "The rattlesnake has a poison-fang for
its own defense and for the destruction of its prey," says the Origin's
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250 DAVID J. DEPEW
"I" (201). But on the principles of natural theology the Creator also
doles out to the snake's natural enemies vulnerability to poison, bal-
ancing harm to one species against the good of another. The Origin's
"I" caustically notes, "Some authors [even] suppose that at the same
time this snake is furnished with a rattle for its own injury, namely,
to warn its prey to escape. . . . [But] I would almost as soon believe
that the cat curls the end of its tail when preparing to spring in
order to warn the doomed mouse" [Origin, 201).
It was to steer clear of just such difficulties that Robert Chalmers
conceded in his Bridgewater Treatise that natural history tells less
"distinctly and decisively of [God's] attributes" than do moral expe-
riences like the call of conscience. That is because Chalmers con-
cedes that "the serpent's tooth for the obvious infliction of pain and
death upon its victims might furnish as clear an indication of design,
though a design of cruelty, as an apparatus for the ministration of
enjoyment . . . might furnish ... a design of benevolence" (Chalmers
1833, 38). The Origin's "I" does better on this troubled subject pre-
cisely by staying on the terrain of natural history. Natural selection
is as competent as the Creator to produce the snake's adaptations
and those that enable its competitors to protect themselves. But it
does not weigh the vulnerabilities of one species against another
for the simple reason that vulnerabilities cannot be objects of its
scrutiny at all. It is blind to everything but "the improvement of
each being" and so cannot possibly be either malicious or haplessly
compromising. 3
In this respect, the moral power of selection's agency or power
actually increases as its early personification as an all-seeing agent
recedes. In its most mature formulation, natural selection trumps
a God who might consciously choose evils for one species in order
to benefit others. This aspect of creationist theodicies, and even
more their anthropocentric assurance that humans get the better of
every bargain, had always offended Darwin. As early as 1837, he was
protesting Whewell's claim that "length of days adapted to duration
of sleep of man!!! whole universe so adapted!!!" as an "instance of
arrogance" [Notebooks, D 49). For the Origin's "I," natural selection
is not cruel or morally indifferent, as Darwinians who abandoned
3 I must pass over the possible ambiguity in "each being."
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The Rhetoric of the Origin of Species 251
the metaphor of selection for "survival of the fittest" came to think.
Because its sole object must be the good, the speaker's claim that
"the vigorous, healthy and happy survive and multiply" [Origin,
79) echoes Paley's proclamation that "it is a happy world after all"
(Lennox 1994).
Is it special creation or evolution by natural selection that now
seems "perfectly natural" in the light of the cultural grammar? I
leave it to historians and biographers to say whether, or at what peri-
ods in his life, Darwin embraced, transformed, or rejected British
natural theology. 4 What matters for a rhetorical reading is that
the Origin paints natural selection's scrutiny as sublimely oriented
toward the good of each being in order to enlist the assumed affective
and argumentative dispositions of its audience. The beauty of the
metaphor's semantic range is that readers may interpret the Origin's
value judgments in as materialistic, Romantic, or crypto-theistic a
frame as they wish.
IV. THE INDISPENSABILITY OF METAPHOR
Any rhetorical account of the Origin must consider whether Dar-
win's metaphors are or are not indispensable to the discovery, intel-
ligibility, and epistemic worth of his "one long argument." In no
sense are they merely decorative. They were certainly indispensable
to Darwin's creative theorizing ( Kohn 1996; Beer 2000, 89). They are
also indispensable to what I have been calling his natural theodicy.
Darwin's metaphors - natural selection as analogous to the breeder's
art, the struggle for existence, the scrutiny image, the economy of
nature, the branching tree of life - are parts of an interactive system
(Beer 2000, 89). Their center of gravity is the numinous kinship con-
ferred on all living beings by common descent. This kinship takes
the place in Darwin's natural theodicy of the collapse of the Great
Chain of Being from whose last tattered remnant - the qualitative
4 Whether Darwin was the last of the natural theologians or their materialist gravedig-
ger is a disputed question. Darwin's Romanticism is a third, increasingly compelling
view. See Manier (1978), Richards (2002), Sloan (2001, 2005). I agree with Kohn
(1989, 1996) that Darwin's aesthetics keeps natural theology and materialism bal-
anced on a knife's edge.
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252 DAVID J. DEPEW
superiority of man to beasts - Lyell, for one, could never free him-
self. Hence the Origin's natural theodicy could not even be formu-
lated without its system of interacting metaphors. They cannot be
"skimmed off" (Beer 2000, xiv, xxv; Levine 2006, 280, n. 3). Whether
the circle of metaphors that licenses this theodicy can be "skimmed
off" without damaging the coherence, intelligibility, and explanatory
power of Darwin's scientific theory itself, however, is a different and
more difficult question. I, for one, think not.
Analogies that encode real scientific knowledge must reveal the
point at which they become disanalogous. Otherwise, what liter-
ary people prize as polysemy and logicians scorn as ambiguity will
throw valid reasoning into disarray. In the Origin's image of natu-
ral selection as scrutinizing even the slightest differences, inner or
outer, that might serve the good of their possessors, the contrast
between artificial selection's self-serving superficiality and natural
selection's other-orientedness marks just such point of disanalogy.
This contrast moves the intentional agent who is so causally promi-
nent in the breeder's art from foreground to background, allowing the
vera causa to which the metaphor points to ground objective knowl-
edge that would be missed or misconstrued if represented otherwise.
It allows the causal mechanism of artificial selection, for example,
to be reflexively explained by reference to its natural counterpart,
showing "that the two [and sexual selection as well] . . . have a gen-
uine identity or common nature" rooted in the same material causal
processes (Gayon 1998, 51).
The speaker affirms the explanatory indispensability of the image
of benign and pervasive scrutiny at precisely those points where the
text sets out conditions for its own falsification. "If it could be proved
that any part of the structure of any one species had been formed
for the exclusive good of another species," the speaker concedes, "it
would annihilate my theory" [Origin, 201 ). 5 But the good of each
species depends on the tight fit between organisms and their niches,
which in turn depends on the gradual shaping of indefinitely small
individual variations into adaptations. So the theory would also
"break down ... if it could be demonstrated that any complex organ
5
Another point about pronouns. When "I" wants "we" to attend to logical structure
and validity, he uses the impersonal pronoun "it" and passive constructions.
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The Rhetoric of the Origin of Species 253
existed which could not possibly have been formed by numerous,
successive, slight modifications" [Origin, 189). Allowing evolution-
ary leaps will loosen adaptive fit. So leaps, too, will falsify the theory
(Origin, 194, 471).
That the speaker is right to regard these entailments as strict is
supported by the fact that Darwin's closest allies had little use for
either his natural theodicy or his image of a benignly scrutinizing
selection and that, not coincidentally, all of them denied one or more
of its entailments. Huxley believed in leaps. Wallace took selection
to work on races more than on individual differences. Spencer never
discriminated clearly between natural selection, whether working
on races or individual differences, and the direct effect of the environ-
ment in molding adaptations. Their differing commitments afforded
Darwin's allies no reason to accept the image of selection as a benef-
icent scrutinizer. Neglecting this image, they changed or misread
Darwin's theory. The reason is not hard to find. Because they had
little use for his natural theodicy, Darwin's false comforters had no
reason to accept what it logically entailed.
The scrutiny image is also necessary if the speaker is to convince
the audience that his theory is not the same as that of "the author
of Vestiges" or vulnerable to objections against him [Origin, 3). The
standing accusation that Vestiges was purely hypothetical tacitly
encoded its failure to conform to a scientific grammar that, ever
since Newton, had put a premium on verae causae showing nature
to be full of inertial tendencies that are shaped by external forces
into an instant-by-instant equilibrium like planetary motion. It was
easy to discount evolutionary theories other than Darwin's because
they often stressed the causal power of inner drives rather than the
shaping role of external forces. In mentioning Vestiges at the outset,
the speaker rejects the very idea of "an impulse . . . advancing . . . the
forms of life" [Origin, 3-4; Variorum, 64: c). "This assumption,"
the Origin's "I" dryly remarks, "seems to me to be no explana-
tion [as it] leaves . . . the co-adaptations of organic beings to each
other and to their physical conditions of life untouched and unex-
plained" [Origin, 4). Natural selection spreads out the emergence
of one species from another by separating the source of individual
variation from its retention in environments made competitive by
the force of Malthusian population pressure operating on a web of
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254 DAVID J. DEPEW
interacting species. 6 Accordingly, instant-by-instant - hence neces-
sarily gradual - adaptive equilibrium among living beings is no less
universal than the force of gravity to which the speaker refers in the
Origin's last sentence [Origin, 490). The upshot is a branching but
ascending tree of life that disavows the idea that higher types emerge
by inner impulses. The Origin thus seeks to take its place with other
characteristic achievements of British science (Depew and Weber
1995).
In view of its influence, it is customary to praise the Origin as
rhetorically successful. It was generally received, however, as George
Eliot's first impression suggests, as new testimony for the "Doctrine
of Development," whose enduring image had already been fixed for
the British public by Lamarck, Chambers, and incipiently Spencer
(Secord 2000). Thus at the indecorous debate of the British Asso-
ciation for the Advancement of Science at Oxford in the summer
of i860, objections long considered effective against Vestiges were
indiscriminately hurled once again at the Origin. Darwin's corre-
spondence in the early 1860s shows him struggling with such mis-
understandings and, in attempts to keep his head above water, pro-
tracting the objection-reply structure into new editions of the Origin
that responded to the changed rhetorical situation created by its first
edition. These texts give us a speaker who is not anticipating and
deflecting trouble, but experiencing it. He can be at times defensive,
didactic, overly accommodating, and even a little testy. He steps out
of character in a new chapter on "miscellaneous objections" to com-
plain, for example, that "it would be useless to discuss them all, as
many have been made by writers who have not taken the trouble to
understand the subject" [Variorum, 226: d). Yet under pressure from
readers who (mis)read natural selection as a mythical agent, he all
too obligingly undercuts the necessity of the metaphor, saying that
the phrase is "almost necessary for brevity" in reporting facts that
might in principle be put otherwise [Variorum, 165: c).
6
Hence Darwin's annoyance with himself for his ambiguous shorthand in the
Origin's thought experiment about how "a bear" might become "a whale." [Origin,
215; Correspondence, 7: 176). Still, Darwin took his dynamical model to be
consistent with a fairly strong recapitulationism. See Richards (2002 and this vol-
ume), Nyhart (this volume).
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The Rhetoric of the Origin of Species 255
Still, Darwin largely resisted Wallace's imprecation that he sub-
stitute Spencer's "survival of the fittest" for natural selection [Cor-
respondence, 14: 227). Perhaps he realized that wide dissemina-
tion of that phrase would mark the emergence of the disenchanted
Darwinism that forever left behind the rhetorical situation to which
the Origin's "I" had addressed himself. 7
7 I am grateful to the editors for commissioning this paper and to them and my fellow
authors for helping me improve it. David Kohn, Lynn Nyhart, Bob Richards, and
Betty Smocovitis provided detailed suggestions. Gillian Beer, John Angus Campbell,
Bruce Gronbeck, John Grula, Michael Ruse, and Rachel Avon Whidden offered
various sorts of inspiration and correction.
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JOHN HEDLEY BROOKE
14 "Laws impressed on matter
by the Creator"?
The Origin and the Question
of Religion
In November 1859, on tne brink of publication and eagerly antic-
ipating the reaction of the naturalists he most respected, Darwin
confided to Alfred Russel Wallace: "If I can convert Huxley I shall be
content" (Correspondence, 7: 375). A month later he had apparently
succeeded, reporting that Huxley "says he has nailed his colours to
the mast, and I would sooner die than give up, so that we are in as
fine a frame of mind ... as any two religionists" [Correspondence, 7:
432).
The conversion to which Darwin referred was not to an atheis-
tic or materialistic worldview. His goal had been more modest: to
corroborate the view that species were mutable and that to explain
their appearance it was unnecessary to invoke separate acts of cre-
ation. The use of religious language is, however, revealing and was
not confined to the metaphor of conversion. Belief in the trans-
mutation of species was described as heretical, as when Darwin
thanked Huxley for being "my good and admirable agent for the
promulgation of damnable heresies" [Correspondence, 7: 434). After
receiving "unmerciful" admonition from his old Cambridge friend
Adam Sedgwick, Darwin described himself as a "martyr" [Corre-
spondence, 7: 430). As in religious communities, so in the scientific:
Darwin exploited personal testimony. "Boastful about my book," he
informed a French zoologist as early as December 5, 1859, that "Sir
C. Lyell, who has been our chief maintainer of the immutability of
species, has become an entire convert; as is Hooker, our best &. most
philosophical Botanist; as is Carpenter, an excellent physiologist, &.
as is Huxley; & I could name several other names." Reinforcing the
rhetoric, he added that these naturalists "intend proclaiming their
full acceptance of my views" [Correspondence, 7: 415-16.). In a less
256
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The Origin and the Question of Religion 257
boastful overture to the American geologist James Dana, he wrote
of "difficulties ... so great that I wonder I have made any converts,
though of course I believe in truth of my own dogmas" [Correspon-
dence, 7: 462-3).
This stock of religious metaphor might be seen as nothing more
than linguistic embellishment; but it points to something deeper. It
underlines a difficulty Darwin faced in winning converts. His own
conversion, as he explained to the Oxford geologist John Phillips, had
taken "many long years" [Correspondence, 7: 372). Writing to Lyell
he used a phrase that he would later apply to his religious views:
"many & many fluctuations I have undergone" [Correspondence, 7:
353). Yet he had to hope that by staggering his readers with his alter-
native vision of the history of life, he could win converts quickly.
He pleaded with them to read his text from beginning to end to
grasp its force. The religious metaphors also indicate that two com-
peting paradigms were in contention and that cautious, mediating
positions would have the air of compromise. When Phillips sought
to restrict the scope of "descent with modification" by confining it
within each separate "essential type of structure," he adopted a posi-
tion for which Huxley already had a colourful slur. Darwin propelled
it to Lyell: "Huxley says Phillips will go to that part of Hell which
Dante tells us is appointed for those who are neither on God's side
nor on that of the Devil's" [Correspondence, 7: 409-10).
This was a conspiratorial joke, but one that signals deeper layers of
controversy. Those who believed that a theory of separate creation
was fundamental to their religious faith saw an immediate threat
from Darwin's science. The Origin of Species was bitterly attacked,
often by clerics with an amateur interest in the study of nature.
Enduring his metaphorical martyrdom, Darwin was sustained by
the belief that a theory that connected and explained so much that
was otherwise inexplicable could not be off the rails.
PARADIGMS AND LAWS
The impression of two paradigms in contention has often been rein-
forced by anecdotes that have spiced popular accounts of religious
reaction. Whether it is Disraeli proclaiming himself on the side of the
angels rather than the apes, or the bishop of Oxford, Samuel Wilber-
force, humiliated after baiting Huxley with the question whether he
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258 JOHN HEDLEY BROOKE
would prefer to think of himself descended from an ape on his grand-
father's or grandmother's side, the image is of a polarity between
scientific credibility and religious obscurantism. Huxley's famous
retort at the 1 860 meeting of the British Association for the Advance-
ment of Science was that he would rather have an ape for an ancestor
than a certain person who used his great gifts to obscure the truth.
We shall return to this event, which has assumed mythic sta-
tus in the annals of scientific professionalism. It must, however,
be stressed that Darwin's theory was published at a time when the
established Church in England was seeking to cope with multiple
crises. These included the challenge from historical criticism of the
Bible, on the subject of which Wilberforce expressed an even greater
dismay when condemning Essays and Reviews (i860). Among con-
tributors to this collection were Oxford clergy who were suggesting
that the Bible should be read like any other book, its authors men of
their times, inspired but fallible in their understanding. The Angli-
can Church was also on the defensive because of the vitality of dis-
senting Christian denominations and a dispiriting loss of members
to the Church of Rome, following the lead of John Henry New-
man. Most of Wilberforce's close relatives were defectors. Initially,
at least, the Darwinian challenge was of lesser moment, though it
undoubtedly added to a sense of crisis when serious thinkers were
questioning the foundations of the Christian faith.
The impression of one cultural paradigm fading as another, sec-
ular in spirit, gained the ascendancy can also be reinforced by the
poignant remarks of Darwin's scientific contemporaries. Harvard's
Professor of Geology and Zoology Louis Agassiz favoured an ide-
alist account of the history of life as the unfolding of a plan con-
ceived in the mind of God. He once wrote that "there will be no
scientific evidence of God's working in nature until naturalists have
shown that the whole creation is the expression of thought and not
the product of physical agents" (Roberts 1988, 34). This was not
what Darwin had shown! Following a scientific meeting in Boston,
the British physicist John Tyndall recalled how Agassiz, "earnestly,
almost sadly," had confessed that he had not been "prepared to see
Darwin's theory received as it has been by the best intellects of our
time." Its success, Agassiz conceded, "is greater than I could have
thought possible" (Tyndall 1879, 2: 182). It was as if an older, more
spiritual understanding of nature was passing away.
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The Origin and the Question of Religion 259
Some of Darwin's own observations resonate with a feature of
paradigm change that Thomas Kuhn would stress in his influential
book The Structure of Scientific Revolutions (1962). Kuhn argued
that because of a degree of incommensurability between competing
scientific paradigms, the triumph of the new over the old may not
flow from a clinching disproof of the one from within the frame-
work of the other. Rather, the newer explanatory scheme gradually
displaces its predecessor as a younger generation of scientists adopts
it and explores its greater possibilities. In the last chapter of the
Origin, Darwin anticipated such an eventuality: "A few naturalists,
endowed with much flexibility of mind, and who have already begun
to doubt on the immutability of species, may be influenced by this
volume; but I look with confidence to the future, to young and rising
naturalists who will be able to view both sides of the question with
impartiality" [Origin, 482). This was hardly music to the ears of an
older naturalist, Adam Sedgwick, who duly chastised his former stu-
dent for the "tone of triumphant confidence in which you appeal to
the rising generation" [Correspondence, 7: 397).
Not surprisingly, then, the Darwinian "revolution" is routinely
interpreted as the triumph of a secular scientific paradigm over a
religiously inspired natural theology, over a philosophy of nature
in which Sedgwick had found evidence of "ten thousand creative
acts" (Brooke 1997, 54) as new species first appeared in the fossil
record. It is certainly possible to streamline the history with such
an interpretation; but it is not the whole story. From the pages of
the Origin itself, it is clear that Darwin could not dismiss questions
that were of fundamental importance to anyone who thought deeply
about the order of nature and why it should be as it is. Defending
his analogy between the birth of individuals and the birth of new
species, Darwin introduced a theological reference: "To my mind it
accords better with what we know of the laws impressed on matter
by the Creator, that the production and extinction of the past and
present inhabitants of the world should have been due to secondary
causes, like those determining the birth and death of the individual"
[Origin, 488). This reference to "laws impressed upon matter by the
Creator" remained through all six editions. What did it mean?
This is an important question because it meant different things
to different thinkers, depending on their particular religious con-
victions. The image was both conventional and powerful, reflecting
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260 JOHN HEDLEY BROOKE
what for some pioneers of European science had been an uncontro-
versial assumption - that one could not have laws of nature without
an external legislator, whose will had been impressed on the world
at its inception. For natural philosophers such as Robert Boyle and
Isaac Newton, the basic properties of matter were as they were not
out of any necessity, but because they had been bestowed by a Deity
who, according to Newton, was "very well skilled in mechanics and
geometry" (Newton 1692, 49).
This way of understanding physical laws had repeatedly found
expression in the literature of natural theology. The law metaphor
did not have to be taken literally. During the Enlightenment there
had been less God-laden accounts of laws of nature, as when David
Hume argued that for an understanding of causal connection one
need look no further than the constant conjunction of cause and
effect in human experience and expectation. Nevertheless, in the dis-
course of natural theology, which Darwin had assimilated in Cam-
bridge, William Paley's view that "a law supposes an agent" was
often echoed.
For religious thinkers the matter did not end there. This was
because several different constructions could be placed on this rela-
tionship between God as lawgiver and the order of nature. One could
envisage a Deity who, having impressed laws upon matter at cre-
ation, ceased to have anything further to do with the world. Nature,
on this view, would be autonomous once it had been created and
structured. This interpretation is often described as "deistic" in con-
trast to a "theism" in which the laws continue to be effective only
because they are constantly sustained by the power of their Cre-
ator. This concept of divine sustenance has been important in the
Christian tradition; but it does not dictate whether divine power
might intervene in special ways - in the working of a miracle, for
example. This means that, conceptually at least, there is space for an
even richer theology of nature in which the laws simply express how
the Deity normally acts in the world but without prejudice to the
question whether there might be additional forms of divine activ-
ity, in miracles or other forms of self-disclosure. For conservative
Christians, the view expressed by the eighteenth- century evangeli-
cal reformer John Wesley has often been compelling: surely a Deity
with the power and wisdom to create such a universe as this can-
not be considered incapable of lesser miracles? These possibilities
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The Origin and the Question of Religion 261
by no means exhaust the range of options. There were semideis-
tic positions in which nature had full autonomy except when there
might be intervention by a deus ex machina - as, for example, in the
origination of new species.
This last position Darwin clearly contested, but in other respects
his reference to "laws impressed upon matter by the Creator" had an
ambiguity that could lead to alternative deistic or theistic readings.
Given that in his early transmutation notebooks he had referred to a
Creator who creates "by laws," it becomes important to ask which
gloss Darwin would have placed on his formulation in the Origin.
His old Cambridge mentor John Henslow had no doubt, declaring
that Darwin "believed he was exalting & not debasing our views of
a Creator, in attributing to him a power of imposing laws on the
organic World by which to do his work, as effectually as his laws
imposed upon the inorganic had done it in the Mineral Kingdom"
[Correspondence, 8: 200).
DARWIN BEFORE THE ORIGIN
When Darwin had first studied with Henslow, he had been prepar-
ing for the life of a priest in the Anglican Church. In the intervening
years, that intention had been displaced by the lure of a life in sci-
ence, which had become all-absorbing during the Beagle voyage.
Although Darwin scholars have disagreed over the precise date by
which he abandoned Christianity, he had certainly done so by the
time he composed the Origin. The primary reasons did not emanate
from his science. True, he saw the sciences contributing to a world-
view in which miracles were increasingly incredible. It is also true, as
his wife Emma had anticipated before their marriage, that the high
standards of evidence required by rigorous science could induce a
sceptical frame of mind when appraising evidence for other forms
of belief. But the triggers for his loss of faith largely came from
elsewhere.
In common with other early Victorian intellectuals, Darwin had
experienced a moral aversion to Christian teaching on heaven and
hell. The notion that those outside the fold of Christian ortho-
doxy (and this applied to his atheist brother Erasmus and his free-
thinking father) were destined for eternal damnation he considered
a "damnable doctrine" [Autobiography, 87). He recounted later that
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262 JOHN HEDLEY BROOKE
he had always considered the presence of so much suffering in the
world one of the strongest arguments against belief in a beneficent
deity. Tellingly, he added that pain and suffering were what one
would expect on his theory of natural selection. Early in 1 85 1 he had
been devastated by the death of his young daughter Annie, finding
it incomprehensible how a God of love could allow such an inno-
cent child to suffer. At the same time he had been reading books
by religious thinkers - notably Francis Newman's Phases of Faith -
whose pilgrimage into unbelief had features in common with his
own (Desmond and Moore 1991, 37 6-8 ) . Add to these considerations
the fact that, as early as March 1 83 8, he had flirted with a materialist
account of the workings of the mind, even suggesting that love of
the Deity might simply be an effect of the brain's organisation (Kohn
1989), and it becomes clear that we should not look in the Origin for
a Christian theism.
THEOLOGICAL LANGUAGE IN THE ORIGIN
Darwin's reference to "laws impressed upon matter by the Creator"
was one of few theological remarks in the first edition of the Origin.
There are, however, several reasons why theological implications
would be read into his text. Central to his rhetorical strategy was the
antithesis between the explanatory power of natural selection and
the sterility of what he called the "theory of creation." In his last
chapter he reemphasised that the geographical distribution of species
could be perfectly understood if there had been migration of species,
followed by gradual modification - as in the striking case of the
Galapagos fauna, which most closely resembled, but also devi-
ated from, the species of mainland South America. How could one
explain, on the basis of separate creation, why some oceanic islands
were teeming with life similar to that on a nearby continent, while
others, equally habitable but distant from major land masses, were
dismally populated by a few bats ? To invoke the will of a Deity would
simply shut down the enquiry. Today evolutionary biologists with
Christian convictions would simply say that the Christian doctrine
of creation does not require belief in what Darwin called a "theory
of creation." And they would be correct in saying that, in its clas-
sic formulation, it is a doctrine about the ultimate dependence of
all that exists (including evolutionary processes) on a transcendent
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The Origin and the Question of Religion 263
power. But Darwin certainly had readers who felt that their faith
was being challenged by the severity with which he denounced the
model of "independent acts of creation."
A second implication of the text was that it was no longer neces-
sary to regard each species as specially designed and adapted for its
particular niche. The argument for design based on intricate anatom-
ical contrivances such as the human eye, in which Paley had so
delighted, was rendered nugatory if, as Darwin was proposing, nature
could counterfeit the design. If natural selection worked for the grad-
ual improvement of each species, it was not surprising that there
was the appearance of design, albeit illusory.
Readers would, however, find toward the end of Darwin's book
some theological remarks that were far from atheistic. He did not just
refer to a Creator who had impressed laws on matter. His language
when discussing the original primordial forms incorporated a biblical
image. This was the breathing of life into them: "I should infer from
analogy that probably all the organic beings which have ever lived
on this earth have descended from some one primordial form, into
which life was first breathed" [Origin, 484). And the image was
repeated in the last sentence of the book: "There is grandeur in this
view of life, with its several powers, having been originally breathed
into a few forms or into one; and that, whilst this planet has gone
cycling on according to the fixed law of gravity, from so simple a
beginning endless forms most beautiful and most wonderful have
been, and are being, evolved" [Origin, 490).
Although Darwin had rejected Christianity and would eventually
become an agnostic, at the time of writing the Origin there is still
a sense in which he wishes to persuade his readers that their God
is too small. Surely, it was beneath the dignity of the Deity to have
produced each species separately as if by so many conjuring tricks!
In his third transmutation notebook he had addressed precisely this
issue. Was not the notion of God's creating by law "far grander"
than the "idea from cramped imagination that God created . . . the
Rhinoceros of Java & Sumatra, that since the time of the Silurian he
has made a long succession of vile molluscous animals. How beneath
the dignity of him, who is supposed to have said let there be light
and there was light" (Brooke 1985, 47). In the first "Sketch" of his
theory, completed in 1 842, he had insisted that the existence of laws
governing the origin of new species did not diminish but "should
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264 JOHN HEDLEY BROOKE
exalt our notion of the power of the omniscient Creator" (Brooke
1985, 47)-
This strand in Darwin's thinking, coupled with his reference in
the Origin to the laws stemming from a Creator, lends plausibility
to the view that in 1859 ne was a deist - one who had rejected reve-
lation as a source of knowledge but who was unwilling to regard the
laws of nature as either self-explanatory or accidental. As becomes
clear from his correspondence with the American botanist Asa Gray,
he had not yet dropped the belief that the laws governing variation
and natural selection might themselves be designed. There is no
indication in the Origin of belief in a Deity providentially supervis-
ing every detail of the evolutionary process; but the possibility of a
higher purpose behind the order of nature is not excluded. Indeed, as
Robert Richards argues in this volume, Darwin's language encour-
ages that construction.
On this interpretation, Darwin held a perfectly consistent posi-
tion in 1 85 9. Acts of creation from an intervening Deity were unnec-
essary to explain the sequences of species in the fossil record. At the
same time, the word 'creation' still had fundamental meaning when
reserved for the ultimate origin of the universe and the laws that had
made possible what Darwin saw as the highest good - the production
of the higher animals. In the first edition of the Origin he did still
use the word 'creation' when referring to nature's productivity, even
while ascribing it to secondary causes. This practice was particularly
striking in the context of the first primordial form. Here he contem-
plated the vast "ages which have elapsed since the first creature,
the progenitor of innumerable extinct and living descendants, was
created" [Origin, 488). There was clearly an ambiguity here, which
Darwin eventually resolved in the fifth edition by replacing "was
created" with "appeared on the stage" [Variorum, 757). One might
see in this change evidence of his growing agnosticism, or simply an
attempt to avoid misleading language.
The first changes that he made to his book, however, were to add
to, rather than subtract from, references to a Creator. He evidently
wished to offer reassurance that his theory did not contravene a
sophisticated understanding of what 'creation' might mean. To the
sentence that referred to "one primordial form, into which life was
first breathed," he added the three words "by the Creator," repeating
the same move in the book's last sentence. Nor were these the only
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The Origin and the Question of Religion 265
additions for his second edition. In the first, he had conspicuously
placed quotations from Francis Bacon and William Whewell at the
head of his text, passages carefully chosen to legitimate, both scien-
tifically and theologically, his enquiry into the secondary causes
of species production. As master of Trinity College Cambridge,
Whewell was a deeply respectable figure who had written exten-
sively on natural theology and the history and philosophy of sci-
ence. From his Bridgewater Treatise (1833), Darwin extracted the
statement that "with regard to the material world, we can at least
go so far as this - we can perceive that events are brought about
not by insulated interpositions of Divine power, exerted in each par-
ticular case, but by the establishment of general laws" [Origin, ii).
There was opportunism in Darwin's appropriation of this passage,
since Whewell would have balked, and did so (Snyder 2006, 195), at
its application to the creation of human beings. But, from Darwin's
perspective, here was a theologically respectable endorsement of his
explanatory programme. From Bacon's Advancement of Learning
(1605), he extracted a statement to the effect that it was not sacri-
legious, but rather a religious duty, to improve one's proficiency in
understanding the book of nature, the book of God's works [Origin,
ii). For his second edition, when it was clear he should do still more
to pre-empt religious objections, he found the perfect theological
precedent in a classic work of Christian apologetics, Joseph Butler's
An alogy of R eligion (1736).
There is irony here, perhaps, in that Butler had been battling with
the deists of his day, arguing that obscurities in the meaning of Scrip-
ture (on which the deists pounced) might, with further research, be
clarified - just as obscurities in nature yielded to scientific research.
The passage that worked for Darwin was this: "The only distinct
meaning of the word 'natural' is stated, fixed, or settled; since what
is natural as much requires and presupposes an intelligent agent to
render it so, i.e. to effect it continually or at stated times, as what
is supernatural or miraculous does to effect it for once" [Variorum,
ii). Butler was renowned as a subtle apologist, and here was a sub-
tle self-defence for Darwin: the appeal to natural causes in species
production was not ultimately to negate the action of an intelligent
agent.
The view of another clergyman entered the second edition. Dar-
win was grateful to the Revd. Charles Kingsley for a letter in which
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266 JOHN HEDLEY BROOKE
he stated what Darwin had certainly once believed and was glad to
hear: "I have gradually learnt to see that it is just as noble a con-
ception of Deity, to believe that he created primal forms capable of
self development into all forms needful . . . , as to believe that He
required a fresh act of intervention to supply the lacunas which he
himself had made. I question whether the former be not the loftier
thought" [Correspondence, 7: 380). With Kingsley's permission,
Darwin reproduced this affirmation, which he described to his
friends as "capital" [Variorum, 748).
That Darwin had to avail himself of such remarks in the hope of
placating hostile critics has sometimes led to the supposition that
his references to a Creator were merely placatory and not to be taken
seriously. This is not a straightforward matter. He was certainly anx-
ious to minimise offence. He was also incensed by reviews (of which
the very first, in the Athenaeum, was an inauspicious omen) that
ignored the cogency of his argument, dwelling instead on its suppos-
edly damaging implications for religion. Darwin fulminated against
the Athenaeum reviewer: "the manner in which he drags in immor-
tality, and sets the priests at me, and leaves me to their mercies
is base" [Correspondence, 7: 387). Moreover, in a letter to Hooker,
written in March 1863, he claimed that he had "long regretted" hav-
ing "truckled to public opinion, and used [the] Pentateuchal term
of creation" [Correspondence, 11: 278). This was a reference again
to those first primordial forms into which life had been breathed.
By 1863 he could tell Hooker that what he had really meant was
nothing more than "appeared" by some wholly unknown process.
A naturalistic account of the origin of life was, however, perfectly
consistent with his deistic outlook, and the reasons for his regret
are more complicated than one might first imagine. Because of his
biblical language, he elicited sympathy from some religious writers
who seized the opportunity to plug the gaps with their gods. But he
also created an opening for fellow naturalists to accuse him of a less
than fully naturalistic account.
Prominent among them was his critic Richard Owen, who
claimed to have advanced an evolutionary theory before Darwin.
Prior to Darwin's publication, Owen had hinted at natural causes
in species development but in exceedingly veiled language (Owen,
1849). I n his review of the Origin, he objected that Darwin had pre-
maturely jumped to a mechanism of change (Owen, 1 860). But Owen
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The Origin and the Question of Religion 267
was insistent on a complete continuity of secondary causes in the
history of life and had been paining Darwin with the insinuation
that, because he had failed to achieve that in the context of the ori-
gin of life, he was unworthy of the crown that Owen reserved for
himself. So when the "Pentateuchal term" was deleted (though not,
interestingly, in the last sentence) from the third edition, the moti-
vation in part was to protect himself and to deflate Owen [Corres-
pondence, 11: 278).
Darwin's remarks on the role of a Creator are often ambiguous.
But statements made in response to social pressures are not nec-
essarily disingenuous. As we have seen, Darwin held a consistent
position in 1859 i n which there was space both for a naturalistic
science of species production and for a Creator whose laws made the
process possible. As he confided to Asa Gray in May 1 860, "I can see
no reason, why a man, or other animal, may not have been aborigi-
nally produced by other laws; & that all these laws may have been
expressly designed by an omniscient Creator, who foresaw every
future event &. consequence" [Correspondence, 8: 224). This was a
philosophy of nature that, with its emphasis on divine laws, he hoped
theists could share with him. He could see "no good reason why the
views given in this volume should shock the religious feelings of any
one" [Variorum, 748). But they did.
RELIGIOUS RESPONSES TO THE ORIGIN
To say that Darwin shocked the religious sensibilities of his contem-
poraries, and in some constituencies still does so today, is almost a
truism. To construct a balanced account of the religious responses is,
however, a major challenge and one that has given rise to a massive
literature, including a recent evaluation of the Darwinian impact
on the Jewish tradition (Cantor and Swetlitz 2006). A fuller account
than can be given here is available in The Cambridge Companion
to Darwin (Brooke 2003). It is easy to list the issues that worried
religious commentators, particularly those concerning human dig-
nity, the authority of sacred texts, and the erasure of Providence
and design. But what for one thinker was of fundamental concern
and a reasonable ground for rejection was, for others, of less signif-
icance. We have already seen that Kingsley delighted Darwin with
his sympathetic response. The same was true of Asa Gray, Harvard's
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268 JOHN HEDLEY BROOKE
devoutly Presbyterian professor of botany, who not only impressed
Darwin with his grasp of natural selection but also suggested that if
severe competition for limited resources was the motor of the evo-
lutionary process, without which the highest forms of life would
never have developed, then this insight might assist the theologians
in their wrestling with the problem of pain and suffering.
Darwin and Gray would part company on whether design was
still discernible in the structures and adaptation of living organisms,
but this issue was not of universal concern to religious minds. It
was a concern for Charles Hodge at Princeton, whose Presbyterian
theology could accommodate the reality of evolution but not the
specifically Darwinian mechanism of natural selection - a position
he made clear in his book What Is Darwinism! (1874). By contrast,
for the Anglican-turned-Catholic John Henry Newman, the fact that
Darwin had undermined one of Paley's arguments for God's exis-
tence was of little consequence, for Newman had already decided
that arguments for design contributed nothing to the basic doctrines
of Christianity.
Objections based on Scripture, and on the book of Genesis in par-
ticular, were voiced from the outset. The clerical naturalist Leonard
Jenyns informed Darwin early in January i860 that he doubted
whether the image of man as an even "greatly improved orang"
would find general acceptance: "I am not one of those in the habit
of mixing up questions of science and scripture, but I can hardly see
what sense or meaning is to be attached to Gen: 2.7. &. yet more
to vv. 21. 22, of the same chapter, giving an account of the cre-
ation of woman, - if the human species at least has not been created
independently of other animals" [Correspondence, 8: 14). For Jenyns
and for many others, including Darwin's wife, it was difficult to see
how the moral sense could have developed from "irrational progen-
itors." By contrast, one attraction of evolutionary ideas for some
Christian theologians was that a process of cultural evolution could
be superimposed on the biological, permitting the argument that
human understanding of the Deity (and of consequential moral obli-
gations) had been progressively refined and that this trajectory was
discernible in successive books of the Bible. To renounce a literal-
istic reading of Genesis was not necessarily to renounce the belief
that human beings ultimately owed their existence to a transcendent
God.
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The Origin and the Question of Religion 269
However, the sense in which Darwin had seemingly placed the
Deity at arms length, deleting the necessity for divine intervention
in the natural order, worried those who cherished a more intimate
relationship between God and the world and who looked to the sci-
ences, as well as to history, for support. The question was whether,
despite Darwin's reserve, evolutionary processes could be combined
with belief in a God who had providential control over their conse-
quences. There is irony here, because Darwin's metaphor of natural
selection was sometimes seized by Christian theists to legitimate
a providentialist interpretation. Darwin had chosen the metaphor
with reference to the selection practised by breeders when seeking to
accentuate particular features of animals and birds in captivity. The
analogy played a crucial role in the rhetoric of the Origin because it
helped him to collapse an absolute distinction between species and
varieties. Thus he observed that even well-trained ornithologists
would be tempted to regard the different varieties produced by the
pigeon fanciers as separate species if they did not already know they
all derived from the common rock pigeon. But if human intelligence
and purpose were involved in the selection of the most propitious
individuals for breeding under domestication, might not the anal-
ogy support the mediation of a divine intelligence and purpose in
the natural order? This was a sufficiently common response to take
the sting out of the theory for those so minded, and for Darwin to
feel it necessary to scotch the misunderstanding of his position. In
later editions of the Origin, he gave even greater emphasis to the
unconscious and unwitting features of the breeders' activity. The
metaphysical ambiguity associated with the metaphor of selection
also encouraged him to follow Wallace's advice and to introduce the
"survival of the fittest" as a synonym for natural selection.
Darwin's theory was a divisive but not necessarily destructive
force within Christendom. One reason it was valued by Asa Gray
was the support it could lend to the ultimate unity of the human
species. The subtitle of the Origin, "The Preservation of Favoured
Races in the Struggle for Life," could easily be used to sanction the
persecution of one race by another that considered itself superior.
In New Zealand, for example, Darwinism was invoked to justify
the suppression and even extermination of the Maori (Stenhouse
1999). For Darwin, however, and indeed for Wallace, the implications
of the theory were otherwise. There was no justification for racial
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270 JOHN HEDLEY BROOKE
subjugation or for the practice of slavery because all humans had
ultimately derived from a common ancestor. It was this support for
monogenism that Gray found so attractive and a welcome contrast
to the polygenism of Agassiz.
In the diversity of religious response there is an important qual-
ification to popular treatments of the Wilberforce/Huxley debate,
which sometimes suggest that Wilberforce typifies the religious
reaction. At the i860 Oxford meeting were other Christian clergy
more open to Darwin's extension of scientific naturalism. One was
Frederick Temple, who later became archbishop of Canterbury. The
divisiveness of the Darwinian theory is particularly poignant here
because Temple had been one of Wilberforce's ordinands, deeply
upsetting the bishop with his liberal contribution to Essays and
Reviews. In his review of Darwin's Origin, Wilberforce did, how-
ever, put his finger on the most sensitive subject: the question of
human uniqueness:
Man's derived supremacy over the earth; man's power of absolute speech;
man's gift of reason; man's free will and responsibility; man's fall and . . .
redemption,- the incarnation of the Eternal Son; the indwelling of the Eternal
Spirit, - all are equally and utterly irreconcilable with the degrading notion
of the brute origin of him who was created in the image of God and redeemed
by the Eternal Son. (Wilberforce [i860] 1874, 1: 94)
Such a reaction raises many questions that are debated in theolog-
ical circles to this day. It was, however, recognised as an overreac-
tion at the time - not least because in all such disparagement was
the assumption that there could be no special human uniqueness
if humans were derived from brutes. Darwin himself relished that
continuity between animal and human, believing it to be a humbler
and more authentic view than was displayed by those arrogantly
claiming knowledge of their Maker. It was nevertheless possible to
argue that, irrespective of origins, humans did have capacities that
had advanced beyond those of their simian relatives. A heightened
responsiveness to other beings, an ability to imagine the thought
worlds of others, a sense of moral obligation, an aesthetic response
to the beauties of nature, and, for some, a grateful responsiveness
to a supposed Creator of that beauty still remained facets of human
experience. Darwin had been no stranger to them. In his Journal of
Researches, he had reflected on the sublimity of the Brazilian forests
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The Origin and the Question of Religion 271
and the desolation of the Tierra del Fuego, both "temples filled with
the varied production of the God of Nature." No one, he wrote, "can
stand in these solitudes unmoved, and not feel that there is more in
man than the mere breath of his body" (Darwin [1839] I 9 10 / 4731-
ST. GEORGE MIVART AND THE SIXTH EDITION
There was one response to Darwin's theory that, despite the protes-
tations of its author, was seen by Darwin's inner circle, and by
Huxley in particular, as insidiously and religiously motivated. This
was a critique from St. George Jackson Mivart, a convert to Roman
Catholicism and, initially at least, a convert to Darwinian evolution.
Mivart, who had been a student of Huxley, remained an advocate of
evolution; but during the 1860s he began marshalling arguments
against the primacy and sufficiency of natural selection. These were
published in his book The Genesis of Species (1871) and were prin-
cipally directed against the gradualness of change that Darwin so
stressed. Mivart argued that extremely small variations and mod-
ifications would be so slight as to confer negligible advantage. He
also exploited gaps in the fossil record, suggesting they were more in
line with sudden discontinuous change than with Darwin's gradu-
alism. Darwin was angered by what he considered the unfairness of
Mivart's attack because, whereas he had tried in the Origin to give
a balanced account of the arguments for and against natural selec-
tion, Mivart dwelled only on the difficulties [Variorum, 242). The
mechanism Mivart preferred involved an internal drive, a complex-
ifying and progressive force, at work in evolutionary development
that operated irrespective of changes in external conditions. Whereas
Darwin had stressed repeated divergence from common ancestors in
a branching and seemingly undirected manner, Mivart looked for evi-
dence of convergence toward recurrent structural forms that could
be interpreted as goal-directed (Desmond 1982, 140, 176-80). Huxley
was particularly embarrassed by Mivart's critique because he con-
sidered it impossible to be a good soldier for science and a loyal son
of the church. Here was one of his own academic progeny purporting
to show that it was not impossible - as long as one's interpretation of
evolution was different from Darwin's. It was not difficult for Hux-
ley to impugn Mivart's motives because the appeal to an inner drive
pushing the evolutionary process in specifiable directions cohered
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272, JOHN HEDLEY BROOKE
with a belief in divine immanence. Was this not a blatant case of
religion interfering with science?
Darwin himself hit back in a new chapter for his sixth edition,
which allowed him to assess the main criticisms he had received -
Mivart's in particular. It is instructive to examine his reply because
Mivart's version of theistic evolution set a precedent for many
responses to the Origin during a long period when it remained
unclear, even to experts in the life sciences, whether natural selec-
tion could be the primary or a sufficient mechanism (Bowler 2000).
Darwin could not stomach Mivart's sudden mutations and innate
tendencies toward perfectibility [Variorum, 241), yet he had to
address a worry that weighed with "many readers" [Variorum, 242-
3 ). This was the alleged impotence of natural selection to account for
the incipient stages of useful structures. There were latent theolog-
ical issues here, because Darwin described Mivart's sudden abrupt
changes as verging on the miraculous [Variorum, 266-7). His really
telling point, however, referred to the power of his own gradualistic
mechanism to explain the phenomenon so beloved by earlier natu-
ral theologians - the beautiful adaptedness of living organisms to the
conditions of their existence [Variorum, 266-7). To suppress the per-
fecting power of natural selection was to sacrifice an explanation for
the very thing that natural theologians, such as Paley, had correctly
identified as in need of explanation.
Whether Mivart's alternative account of evolution had been moti-
vated by, shaped by, or simply produced congruously with his
Catholic spirituality it is difficult to gauge. Human motivation is
notoriously difficult to determine. It is, however, noteworthy that
his emphasis on convergence in separate evolutionary lines does
have contemporary resonance in the discussion of anatomical struc-
tures, such as the human eye, the type of which has appeared many
times (Conway Morris 2003).
darwin's agnosticism
Toward the end of his life Darwin became increasingly agnostic
about religious claims. His cousin Julia Wedgwood even referred
to a "certain hostility" in his attitude toward religion "so far as it
was revealed in private life." She told Darwin's son Frank that he
felt he was confronting an influence that "adulterated the evidence
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The Origin and the Question of Religion 273
of fact" (Brooke 1985, 41). The resistance of religious minds and the
machinations of Mivart contributed to that feeling. Insofar as his
attempts to pacify committed theists were successful, he could still
be discomfited by the confessional superstructures they erected on
his statements. His correspondence with William Harvey, an expert
on South African flora, would constitute an example [Correspon-
dence, 8: 322-32, 370-4).
Along with his deistic metaphysics, the roots of his agnosticism
were already in place when he wrote the Origin. He knew that what-
ever one postulated as the cause of the universe would invite ques-
tions about its cause. There were also certain issues, such as the
apparent contradiction between necessity and free will, and ques-
tions concerning the origin of evil, that he considered "quite beyond
the scope of the human intellect" [Correspondence, 8: 106). He felt
much the same about the question of design in nature, holding the
conviction that so wonderful a universe could not be the result of
chance alone, yet also finding it impossible to see intelligent design
in the details. In i860, he had still hoped to hold the contending ele-
ments together, asking Gray, "Does not Kant say that there are sev-
eral subjects on which directly opposite conclusions can be proved
true?!" [Correspondence, 8: 274). In the ensuing years, this Kantian
solution ceased to satisfy him. During an absorbing correspondence,
in which he assessed Gray's opinion that variations could be under
the control of a superintending Providence, Darwin became con-
vinced that this was no way out of his "hopeless muddle." The
problem was the lack of evidence to support Gray's intimation that
the variations (however caused) appeared with their prospective use
ordained. They surely appeared randomly, and many were detrimen-
tal to the species. The analogy Darwin used to articulate his position
concerned the building of a house by a builder who used stones that
happened to be available in the vicinity. Surely, Darwin argued, no
one would say that the stones had come to be there in order that the
builder could build his house. Gray's revealing concession that the
perception of design had to be through the eye of faith was hardly
likely to bring Darwin around (Moore 1979, 275-6).
The word "agnostic" is, by itself, not especially informative.
Everything depends on the particular beliefs one is agnostic about
(Lightman 1987). A certain kind of agnosticism has been an intrinsic
feature of Christian theology itself in contexts where discourse about
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274 JOHN HEDLEY BROOKE
God is understood to be discourse about the incomprehensible and
ineffable. Even during his later years Darwin denied ever having been
an atheist "in the sense of denying the existence of a God" [Letters,
i : 304). While admitting that his judgement often fluctuated, he was
still prepared to say that he deserved to be called a theist. The image
of a Creator who "creates by laws" still endured, but by the end he
had relinquished the belief that the order of nature necessitated an
inference to purpose. To the feelings of "wonder, admiration, and
devotion" that had once filled his mind, he was now anaesthetised
[Letters, 1: 311). He could still find it inconceivable that the uni-
verse was the result of chance alone. But - and with Darwin there
is so often a nuance - if the human mind was itself the product of
evolution, what confidence could one place in any metaphysical or
theological conviction - even one's own?
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GILLIAN BEER
15 Lineal Descendants
The Origin's Literary Progeny
DARWIN AS READER AND WRITER
Toward the end of his life, in the autobiography written for his
family, Darwin remembers his early enthusiasm for literature and
other arts with melancholy regret, regret for a taste apparently extin-
guished by the oncoming of age and the need for endless empirical
investigations:
My mind seems to have become a kind of machine for grinding general laws
out of large collections of facts, but why that should have caused the atrophy
of that part of the brain alone, on which the higher tastes depend, I cannot
conceive. [Autobiography, 139)
Darwin distinguishes his continued pleasure in 'books on histories,
biographies, and travels . . . and essays on all sorts of subjects' from
his earlier delight in poetry and music:
Up to the age of thirty, or beyond it, poetry of many kinds, such as the
works of Milton, Gray, Byron, Wordsworth, Coleridge, and Shelley, gave me
great pleasure, and even as a schoolboy I took intense delight in Shakespeare,
especially in the historical plays. . . . But now for many years I cannot endure
to read a line of poetry,- 1 have tried lately to read Shakespeare, and found it so
intolerably dull that it nauseated me. Music generally sets me thinking too
energetically on what I have been at work on, instead of giving me pleasure.
I retain some taste for fine scenery, but it does not cause me the exquisite
delight that it formerly did. [Autobiography, 138)
Even as he declares his 'curious and lamentable loss of the higher
aesthetic tastes', faint echoes of former joys return: 'great plea-
sure', 'intense delight', 'exquisite delight' - the expressions evoke
275
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276 GILLIAN BEER
experience not quite forgotten. At this point in the passage he turns
to the anomaly in his capacity for aesthetic pleasure, as he sees it:
On the other hand, novels, which are works of the imagination, though not
of a very high order, have been for years a wonderful relief and pleasure to
me, and I often bless all novelists.
With a certain defensive self-mockery he then declares his taste in
novels:
A surprising number have been read aloud to me, and I like all if moderately
good, and if they do not end unhappily - against which a law ought to be
passed. A novel, according to my taste, does not come into the first class
unless it contains some person whom one can thoroughly love, and if a
pretty woman all the better. [Autobiography, 138-9)
So, ruefully looking back, Darwin presents himself here as one who
now has left to him only lower aesthetic experiences. Many would
dispute his assumption that novels are necessarily not of a high
imaginative order: he is writing in the wake of Middlemarch (1872)
and in the same year (1876) that Daniel Deionda had appeared in part
publication. George Eliot might, however, have met his embargo on
novels with unhappy endings, depending on how the reader responds
to the final pages of each of those novels. Essentially, Darwin seems
to be telling us that in his later life he looks to literature for comfort
rather than elevation ('some person whom one can thoroughly love'),
with a little mild titillation thrown in ('if a pretty woman all the
better').
But this self- description is too easily read back into Darwin's ear-
lier life, and some critics have used it to deny that he ever had strong
aesthetic responses. This runs counter to the elegiac tone of regret
in the passage, which yearns a little for those past intensities of
response. Even more, it denies the precision and enthusiasm of his
descriptive writing, shown at its full in The Voyage of the Beagle
and persisting in the Origin alongside an argued oratory, sometimes
biblical, that insists on reviving so many of the lost forms of life,
apparently expunged by time:
How fleeting are the wishes and efforts of man! How short his time! And
consequently how poor will his products be, compared with those accumu-
lated by nature during whole geological periods. [Origin, 84)
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Lineal Descendants 277
His subtle account of the interdependent structures of any organic
being points out that they are determined
in the most essential yet often hidden manner, to that of all other organic
beings, with which it comes into competition for food or residence, or from
which it has to escape, or on which it preys. This is obvious in the structure
of the teeth and talons of the tiger,- and in that of the legs and claws of the
parasite which clings to the hair on the tiger's body. But in the beautifully
plumed seed of the dandelion, and in the flattened and fringed legs of the
water-beetle, the relation seems at first confined to the elements of air
and water. Yet the advantage of plumed seeds no doubt stands in the closest
relation to the land being already thickly clothed by other plants,- so that the
seeds may be widely distributed and fall on unoccupied ground. {Origin, 77)
Tiger and parasite, dandelion and water beetle, are shown as adapted
not only in relation to their immediate surroundings, but also in their
wider natural milieu. They are, moreover, evoked in the writing:
'clinging', 'beautifully plumed', 'flattened and fringed'.
When in the Autobiography Darwin deplores the difficulty he has
always had in writing 'clearly and concisely', he modestly does not
remark that it is the complexity of what he must simultaneously
show that is a fundamental reason for this problem. He does, how-
ever, acknowledge that such difficulty also has certain intellectual
advantages:
I have as much difficulty as ever in expressing myself clearly and concisely,-
and this difficulty has caused me very great loss of time,- but it has had
the compensating advantage of forcing me to think long and intently about
every sentence, and thus I have been led to see errors in reasoning and in
my own observations or those of others. [Autobiography, 136-7)
So, writing spontaneously, however ill-sorted the first attempt, and
then scrutinising, together make for that temper of enthusiasm and
constant reflection that we encounter in his writing. He continues:
Formerly I used to think about my sentences before writing them down,- but
for several years I have found that it saves time to scribble in a vile hand,
whole pages as quickly as I possibly can, contracting half the words,- and
then correct deliberately. Sentences thus scribbled down are often better
ones than I could have written deliberately. [Autobiography, 137)
The zest of observation and insight impels him forward. Afterward
he can comb through the cluster of his sentences. And he recognises
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278 GILLIAN BEER
that quite frequently the first free dash at expression survives better
than the reasoned enunciation. But both are necessary to test to the
full his argument and his observation.
Darwin, then, drew on literature that he loved during the time
of the formation, as well as the formulation, of his theory. We can
to some extent track that process in the reading lists that are now
included as an appendix to volume 4 of the Correspondence. These
lists begin only on his return from the Beagle voyage and do not note
all the books he was reading, but they do, fascinatingly, often note
how he was reading, even down to differing degrees of skimming:
'skimmed', 'Well skimmed', 'slightly skimmed'. Among the copious
lists, which place mainly scientific books on the left-hand page and
nonscientific books on the right, he includes, among travel books
and volumes on natural history, physiology, and political economy,
many works of literature, both classical and newly published. For
example, he reads Harriet Martineau's novel The Hour and the Man,
based on the life of the black rebel leader Toussaint-l'Ouverture, in
1842, soon after its publication in 1841. Later in that same list, he
is reading Carlyle's Sartor Resartus ('excellent') and his Hero Wor-
ship ('moderate') as well as the minor poems of Milton, a volume of
Wordsworth in March and another in May. He does not much enjoy
Dryden or Bacon or Swift; they all get short shrift: 'Bacon's Essays -
dull, and crabbed style'; 'Tale of Tub - poor'; 'Failed in reading Dry-
den's Poems except Absalom and Ach[itophel] wh. I rather liked'.
The very last entry in these lists, which stretch from 1838 to i860,
is another famous book, with almost as long a publication future as
the Origin, 'Smiles Self-Help (goodish)' [Correspondence, 4: 462-3,
497).
As has by now often been observed, Darwin carried Milton's
Poems with him on his long land journeys during the five-year
voyage of the Beagle. Paradise Lost could furnish the imagina-
tion with descriptions of the genesis of life, and its stretched and
sinewy sentence structure taught much about keeping ideas in sus-
pension alongside each other, avoiding premature closure. Byron's
romantic travels in Childe Harold give scope to the ego discover-
ing itself. During Darwin's youth Wordsworth's Prelude had not yet
been published, but his Excursion gave entry to the life of sojourn-
ing country dwellers and their philosophies, while 'Lines Com-
posed Above Tintern Abbey' sounds the knell that Darwin came to
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Lineal Descendants 279
understand only too well in his retrospect on his own early aesthetic
pleasures.
And now, with gleam of half-extinguished thought,
With many recognitions dim and faint,
And somewhat of a sad perplexity,
The picture of the mind revives again.
(Wordsworth 1969, 164)
Any sailor, especially on so long, trying, and fascinating a journey
as that of the Beagle, could respond to Coleridge's Ancient Mariner
with its uncovering of the random violence induced by tedium:
'God save thee, ancient Mariner
' From the fiends that plague thee thus -
'Why look'st thou so?' -With my cross bow
I shot the ALBATROSS.
(Coleridge 1993, 220)
And Shelley is probably the most informed and ambitious in his
response to scientific thought of any of the poets that Darwin names.
But this Companion is concerned particularly with the Origin,
written in the period after the full intensity of his aesthetic responses
had - according to his late recollections - already slackened. The
writing of that work occupied him over thirteen months as he
approached his fiftieth birthday. By then, what he had learned from
poets and poetry had silted down in his consciousness and was no
longer the object of rapturous attention. Yet it had not gone away.
It was so taken for granted as to be part of the mass of his mind.
I have called this essay 'Lineal Descendants: The Origin's Literary
Progeny': progeny demand forebears.
Understanding Darwin's relation to, and enjoyment of, his copi-
ous and eclectic reading is essential for a full grasp of his powers of
reflection and lateral reach that placed ideas in new relations to each
other. Those qualities of mind were the ones that encompassed the
mass of available empirical material and condensed it into a major
new theory. As George Eliot wrote in The Mill on the Floss (i860),
the first of her works to respond in any measure to the Origin:
In natural science, I have understood, there is nothing petty to the mind
that has a large vision of relations, as to which every single object suggests a
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280 GILLIAN BEER
vast sum of conditions. It is surely the same with the observation of human
life. (Eliot 1980: 238)
The warmth and eloquence of Darwin's writing in the Origin is part
of the persuasive act by which his ideas engage a broad range of read-
ers, scientific and nonscientific. Those readers then work with the
materials of the book to form arguments, observations, and, above
all, stories of their own. The great fresh idea of 'natural selection' has
to struggle within the formulation that Darwin finds for it, a formu-
lation that threatens to reinstate design even as it flouts it: if 'selec-
tion', then by what principles? And is there a ghostly 'selector' mak-
ing the discriminations, haunting the field of the metaphor? Darwin
proposes a dualism of the natural and the artificial: that is, unknow-
ing physical processes as opposed to what is contrived by human
artifice. But the term 'selection' moves between the two zones, act-
ing as an agent, perhaps a double agent. Indeed, expelling agency from
human language is an impossible task. Darwin expressed exaspera-
tion at some of the twists his critics brought to the term: for example,
in the third edition: 'that the term selection implies conscious choice
in the animals which become modified; and it has even been urged
that as plants have no volition, natural selection is not applicable to
them!' [Variorum, 165:14.3-4x1. But in that same paragraph of the
third edition he acknowledges that '[i]n the literal sense of the word,
no doubt, natural selection is a misnomer' (145:0), and in the fifth
edition that becomes 'natural selection is a false term' (14.5:6).
However, he insists on the need for metaphorical language and
buttresses his case with the more established example of chemists:
who ever objected to chemists speaking of the elective affinities of the
various elements? - and yet an acid cannot strictly be said to elect the base
with which it will in preference combine. [Variorum, 165 114.5 :c)
It is a telling example, and one that, intriguingly, had already pro-
vided the ground for fiction in Goethe's great novel Die Wahlver-
wandtschaften (Elective affinities, 1809). That novel opens with a
scene in a garden where the hero is grafting newly cut scions onto
rootstock, and it concerns adultery and unwilled affinities. Goethe
takes the language of chemistry over into human affairs, affairs from
which that technical language had itself sprung. The rapid slide to
and fro between ordinary human concerns and constrained scientific
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Lineal Descendants 281
usage besets Darwin, exacerbated by his wish to write in a language
that any educated person could read. It also provides the creative
space for later writers who have in so many different ways responded
to Darwin, his ideas, his telling of them, and the often incompatible
stories that they have come to inspire.
DARWIN IN LITERATURE NOW
Writers do not simply adopt a scientific idea and carry it through
in their novels, plays, or poems. Sometimes a phrase is enough to
set new responses in motion. Sometimes the general idea is all the
writer needs. As often, it is a problem or contradiction in the ideas
that sets the creative juices flowing. Occasionally the writer is a
close student of all the intricacy of language and theory that the
Origin sets forth: that is the exception. All the examples I shall give,
both from our contemporaries and from earlier writing, show pro-
cesses of transformation, sometimes poised at so extreme an angle
that it cannot be certain how consciously the writer has drawn on
the bank of Darwin's presence. I use the term 'presence' advisedly,
since over the years Darwin himself has been mythologized and is
liable to appear in a variety of guises in works of fiction: at the
turn of the twenty-first century, for example, in Jenni Diski's Mon-
key's Uncle (1994), Roger McDonald's Mr Darwin's Shooter (1998),
and Harry Thompson's This Thing of Darkness (2005). Or in a long
poem like 'Darwin' by Lorine Niedecker (1985), drawing intimately
on his writing and life, from which I quote these stanzas:
A thousand turtle monsters
drive together to the water
Blood-bright crabs hunt ticks
on lizards' backs
Flightless cormorants
Cold-sea creatures-
penguins, seals
here in tropical waters
Hell for FitzRoy
but for Darwin Paradise Puzzle
with the jig-saw gists
beginning to fit (Niedecker 1985, no)
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282 GILLIAN BEER
The fascination with the man has grown stronger in recent years
so that he has become a cultural figure buffeted by the winds of
controversy, and also a remembered human being tenderly imagined
at the end of his life, as in Gejtrud Schnackenberg's poem 'Darwin
in 1 88 1 ' , which ends with Darwin wandering in the garden and then
coming to bed on his last night:
He lies down on the quilt,
He lies down like a fabulous-headed
Fossil in a vanished river-bed,
In ocean drifts, in canyon floors,- in silt,
In lime, in deepening blue ice,
In cliffs obscured as clouds gather and float;
He lies down in his boots and overcoat,
And shuts his eyes.
(Schnackenberg 1986, 22)
Darwin the man, then, is very much part of literature now. Ian
McEwan introduces a sentence from the conclusion of the Origin
near the beginning of his novel Saturday (2005): 'There is grandeur
in this view of life'. The quotation becomes an adamant point of ref-
erence through all the vicissitudes of the long day that McEwan then
explores with his main character, a neurosurgeon. More allusively,
Carol Ann Duffy gives a teasing voice to Emma Darwin:
Mrs. Darwin
7 April 1852.
Went to the Zoo.
I said to Him -
Something about that Chimpanzee over there reminds
me of you. (Duffy 1999, 20)
In this little squib of a poem Duffy is, of course, remembering Dar-
win's interest in the London zoo orangutan and is drawing on the
long Victorian tradition of illustrating Darwin as almost an ape. This
can all be compressed into four lines because by now the life is so
familiar to a variety of readers.
But it is not just Darwin's person that continues to inhabit writers'
imaginations. One of the most compelling later twentieth century
novels to consider the losses of evolution, as well as its strengths,
is William Golding's The Inheritors (1955). This daring and influ-
ential work is presented through the minds of Lok and Fa, gentle
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Lineal Descendants 283
Neanderthals, who try to interpret the behaviour of a new kind of
being, our ancestors. By reversing the usual assumption that Nean-
derthals were brutal and stupid, well overcome by Homo sapiens,
Golding sheds light on the hubris, and the competitive ferocity, of
the human. He also by implication reminds the reader of the out-
rages perpetrated against indigenous people in different parts of the
world as part of the imperial enterprise. The work explores the idea
that the Earth itself is an organism of a superior sort; thus it presages
Gaia and some aspects of recent ecological thinking. Golding's novel
provides a salutary corrective to the notion that the 'survival of the
fittest' (in Herbert Spencer's phrase, adopted by Darwin in later edi-
tions of the Origin) guarantees a morally superior inheritor.
Doris Lessing has twice turned to issues of genetic inheritance,
and to reversion, to fuel her novels. In The Fifth Child (1988) she
imagines a modern liberal family burdened with a male child whom
she conceives as an atavistic monster. In her 2007 novel The Cleft,
she reimagines creation as a lost world of semiaquatic females into
which by genetic chance the aberration of maleness enters through
the birth of a boy. Similarly, though at a further stretch, her five-
volume science fiction sequence Canopus in Argos: Archives (1979-
83) draws by counter-representation on the evolutionary nature of
our customary thinking now. It creates a world in which a new form
of civilization spreads through the planetary system by means of
what she calls 'forced evolution'.
The idea of evolution and the new technological processes that
may drive the human and all surrounding life toward new extreme
conditions trouble writers of many varying degrees of talent and
insight. At its peak, we have writing such as Margaret Atwood's
2003 novel Oryx and Crake. She imagines a post-human world of
genetically engineered beings, but her imagination does not need
to resort to things not already in the world. The disastrous future
that she depicts is generated out of the present. Atwood, herself the
daughter of an entomologist, insinuates a chill and detailed account
of the conditioned behaviours, as well as the feckless choices, that
bring about disaster. Evolution and artificial selection are here at
the extreme distance from Darwin's implicitly benign figuring of
natural selection, which 'can act only through and for the good
of each being' [Origin, 84). Yet Darwin also knew that the future
could not be foreseen or controlled: 'of the species living at any
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284 GILLIAN BEER
one period, extremely few will transmit descendants to a remote
futurity'.
Looking to the future, we can predict that the groups of organic beings
which are now large and triumphant, and which are least broken up, that is,
which as yet have suffered least extinction, will for a long period continue
to increase. But which groups will ultimately prevail, no man can predict;
for we well know that many groups, formerly most extensively developed,
have now become extinct. [Origin, 126)
RESPONSES IN NINETEENTH-CENTURY LITERATURE
That word 'extinct' gathers into it a terror already abroad before the
Origin was published. On the one hand: will humankind progress?
The expected and hoped-for answer among Darwin's contemporaries
was 'yes'. Darwin encouraged that hope in the final paragraph of the
Origin. He there writes of 'the Extinction of less-improved forms':
Thus, from the war of nature, from famine and death, the most exalted
object which we are capable of conceiving, namely, the production of the
higher animals, directly follows. [Origin, 490)
But 'Man', in the Victorian locution, is not distinguished from 'the
higher animals' here: what applies to them, applies to us. And what
Darwin has shown is that most species fail to send descendants
far into the future. So, on the other hand: will humankind sur-
vive? Darwin suggested that mankind, so rarely named apart from
other animals in the Origin, was subject to the same attrition as
all present and past species. That was the chilly message that lay
beneath the emphasis on 'improvement', 'development', and 'com-
plexity'. In one aspect Darwin's emphasis on relationships, the most
important being the relationship of one organism to another, sounds
a note of egalitarianism: 'We possess no pedigrees or armorial bear-
ings; and we have to discover and trace the many diverging lines
of descent in our natural genealogies, by characters of any kind
which have been long inherited' [Origin, 486). But equally, the fine-
shaved balances that decide mortality give little room for individual
optimism.
To understand the rapid impact that the Origin had upon in wider
Victorian society and literature it is important to recognise that
well before its publication in 1859 Robert Chambers's anonymously
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Lineal Descendants 285
published Vestiges of the Natural History of Creation (1844) was
going through a series of editions and revisions that kept the issue
of humankind's relation to the animal kingdom in the foreground of
thought:
Man, then, considered zoologically, and without regard to the distinct char-
acter assigned him by theology, simply takes his place as the type of all types
of the animal kingdom, the true and unmistakable head of animated nature
upon this earth. (Chambers, ed. Secord, 1994: 272-3)
The second half of Chambers's sentence is upbeat ('true and unmis-
takable head'), but the first is more neutral ('the type of all types').
So Man is not set aside for privilege in zoology but manifests all the
attributes of the animal kingdom. Perhaps the most famous cry of
desolation in Victorian literature, and one habitually linked to the
advent of evolutionary theory, is Tennyson's in his great elegy In
Memoriam, particularly in poems 54-6.
'So careful of the type?' but no.
From scarped cliff and quarried stone
She cries, ' A thousand types are gone:
I care for nothing, all shall go.
So opens poem 56, in the voice of nature crying from geological
formations that harbour so many vestiges of extinct life. The poem
continues from line 8 thus, in a prolonged questioning that embeds
the famous 'Nature, red in tooth and claw':
And he, shall he,
Man, her last work, who seemed so fair,
Such splendid purpose in his eyes,
Who rolled the psalm to wintry skies,
Who built him fanes of fruitless prayer,
Who trusted God was love indeed
And love Creation's final law -
Though Nature, red in tooth and claw
With ravine, shrieked against his creed -
Who loved, who suffered countless ills,
Who battled for the True, the Just,
Be blown about the desert dust,
Or sealed within the iron hills?
(Tennyson 1969, 911-12)
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286 GILLIAN BEER
Man, despite his ideals and hopes, may, like all other forms, be
annihilated, present only as mixed dust or geological detritus.
This poem was almost certainly written before the publication of
Chambers's work, and about twenty years before the Origin. It is
responding to Lyell's Principles of Geology (1830-33), a work that
profoundly affected the young Darwin at that time too. Tennyson's
whole sequence of poems was published (first anonymously) in 1850
and rapidly went through a number of editions. Such was its acclaim,
and its closeness to Darwin's own concerns, that it is likely to have
been present in Darwin's consciousness as he moved toward the
writing of the Origin. And Darwin, in the chapter on the 'Struggle
for Existence', parallels, though with less extremity of language,
what Tennyson observed:
We behold the face of nature bright with gladness, we often see superabun-
dance of food; we do not see, or we forget, that the birds which are idly
singing around us mostly live on insects or seeds, and are thus constantly
destroying life. [Origin, 62)
Two pages later the glad face of Nature is subject to assault:
The face of Nature may be compared to a yielding surface, with ten thousand
sharp wedges packed close together and driven inwards by incessant blows,
sometimes one wedge being struck, and then another with greater force.
[Origin, 67)
Such melancholic, and violent, insights are the counter within the
Origin to Darwin's efforts also to construe the complexity of nature
as ultimately harmonious, and enabling perfection:
It is interesting to contemplate an entangled bank, clothed with many plants
of many kinds, with birds singing on the bushes, with various insects flitting
about, and with worms crawling through the damp earth, and to reflect
that these elaborately constructed forms, so different from each other, and
dependent on each other in so complex a manner, have all been produced by
laws acting around us. [Origin, 489)
That ecological and finally orderly, law-governed image is one of the
multiple and contradictory stories to emerge from readings of the
Origin. It can be the story of the genealogical descent of man or,
in a different reading, his ascent from lowly organic beginnings; it
can be an obliterative tale of extinctions past and to come; it can
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Lineal Descendants 287
sustain the intricate ecological balances needed for life to thrive
and survive; it can underpin imperial predations in which the more
advanced seize the space, and are justified in doing so; it can empha-
sise the fundamental need for collaborative and even cooperative
behaviour. Exactly that capacity to sustain quite diverse narratives
helps to explain the creativity of the Origin and its fruitfulness in
those thought experiments called literature.
So within the work a number of competing potentialities occur.
Moreover, when we think about the Origin and literature it is impor-
tant (as my examples suggest) to understand it as part of a network
of discussion, as well as seeing it as a fulcrum. Certainly it acts as a
hinge for fresh connections, and as a support for new ideas. But its
impact would have been less great had it simply stood alone. It is
its implication in, and conversation with, other writing of the time
that generates much of its initial power. That power grew over the
ensuing years.
One can track the presence of the Origin above and below ground
in Victorian literature. Sometimes it is manifest, used as pointer to
a character's free thinking, as in Du Maurier's Trilby (1894), where
the artist hero Little Billee is reading it for the third time. In Eliza-
beth Gaskell's last novel, Wives and Daughters (1866), the character
Roger Hamley, an honest and open natural historian, is modelled on
Darwin. This portrayal is unusual in Victorian literature, where doc-
tors, rather than scientists, tend to be the heroes. But beyond these
direct references, the Origin provides problems for writers to engage
with and stories for them to challenge.
Some of the most striking early responses were expressed through
fantasy. Two contrasting books play with Darwin's ideas to explore
alternatives to current society: Charles Kingsley's The Water Babies
(1863) and Samuel Butler's Erewhon (1874). Kingsley's book is
addressed to children and combines a fierce satire on the practice
of exploiting children - particularly here little boys as chimney-
sweeps, forcing them down chimneys - with a tale of evolutionary
and moral renewal. The child Tom drowns and then goes through the
processes of rebirth in the ocean, following the stages of foetal ges-
tation and drawing on the then-current theory of 'recapitulation', in
which the human being was believed to proceed through the forms of
other kinds to reach the human. It is also a story about what's pos-
sible and what's natural, challenging the assumptions about what
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288 GILLIAN BEER
can be, in the service of religious faith but also in the service of new
scientific thinking. The whole book is a farrago of ideas, insights,
powerful storytelling, and an often very moving exploration of a
lost child's experiences. It also tells its young reader to beware of
denial:
You must not say that this cannot be, or that is contrary to nature. You
do not know what nature is, or what she can do; and nobody knows,- not
even Sir Roderick Murchison, or Professor Owen, or Professor Sedgwick, or
Professor Huxley, or Mr. Darwin, or Professor Faraday, or Mr. Grove, or any
other of the great men whom good boys are taught to respect. They are very
wise men,- and you must listen respectfully to all they say: but even if they
should say, which I am sure they never would, "That cannot exist. That is
contrary to nature," you must wait a little, and see,- for perhaps even they
might be wrong. (Kingsley, n.d., 53-4)
Kingsley was, in fact, one of Darwin's earliest allies and among
the first to understand that there was no necessary contradiction
between natural selection and religious belief. Like Chambers, he
placed God at the generative heart of creation, but refused to see
Him as persistently active. Intriguingly, when he figures this per-
ception he presents it in the form of a woman, Mother Carey, seated
in the middle of the Peacepool:
He expected, of course - like some grown people who should know better -
to find her snipping, piercing, fitting, stitching, cobbling, basting, filing,
planing, hammering, turning, polishing, moulding, measuring, chiselling,
clipping, and so forth, as men do when they go to work to make anything.
But, instead of that, she sat quite still with her chin on her hand, looking
down into the sea with two great grand blue eyes, as blue as the sea itself.
(Kingsley, n.d., 196-7)
The contrast he describes fits the slow, seeming passivity of natural
selection as opposed to the driven activity of artificial selection just
as much as it fits godhead or the creative principle. That may be
Kingsley's point.
Also in 1863, an article headed 'Darwin among the Machines'
appeared in the New Zealand Press newspaper. This was the core
of Samuel Butler's Erewhon: or Over the Range (1872), which, as
Butler himself acknowledged, took inspiration from the Origin. (His
later one-sided quarrel with Darwin has little bearing on this text.)
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Lineal Descendants 289
Erewhon (Nowhere in reverse) is a land where current values are
apparently inverted: the ill are punished for their condition, the
criminal rewarded. But that inversion itself raises questions about
the actuality of current declared values. Perhaps the most enthralling
part of the book is Butler's exploration, in the Book of the Machines,
of the evolutionary potential of machines and their relationship to
Man. On one side of the debate within the book, most argue that
machines have the potential to self-generate and vary: 'Machines
can within certain limits beget machines of any class, no matter
how different to themselves' (Butler 1884: 205). They are therefore
a future threat to the dominance of mankind: 'May not man him-
self become a sort of parasite upon the machines? An affectionate
machine-tickling aphid?' (197) On the other side it is argued that
Man himself 'is a machinate mammal' (218).
The lower animals keep their limbs at home in their own bodies, but many
of man's are loose, and lie about detached. (218)
Umbrellas, for instance: 'If it is wet we are furnished with an organ
commonly called an umbrella' (220). The rich, it is argued, are more
advanced in evolutionary terms because they can own so many exter-
nal limbs. Butler's satiric fantasy is full of perceptions that have since
been realised - the miniaturisation of computers, for example, and
artificial intelligence. His quirky brilliance allowed him to perceive
many of the implications of the Origin that others missed, includ-
ing the problem of kinds and degrees of consciousness in other life
forms.
That perception became the matter of satire as well as resistance
in the work of several notable women writers of the later nine-
teenth century. The large presence of George Eliot in relation to
Darwin has been extensively discussed in many places, including in
my book Darwin's Plots: Evolutionary Narrative in Darwin, George
Eliot and Nineteenth- Century Fiction (1983, 2000). Her responses
can be tracked in the very form of her fictions, particularly in the
later works Middlemarch (1 871 ) and Daniel Deronda (1 878). In Mid-
dlemarch, the search for a single originary explanation proves delu-
sive for two contrasted characters, Casaubon, the mythographer, and
Lydgate, the medic (though in his case the problem is formulating
the necessary question). Instead, the book emphasizes the web of
relations and affinities, the play of kinship and difference, among
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29O GILLIAN BEER
the various groups and individuals in the specific environment of
an English midlands town of the late 1820s. It demonstrates how
interdependent are the fates of those who barely know each other
and how far they are determined by the milieu in which they seek to
survive. The 'large vision of relations' that she earlier ascribed to the
true scientist is here brought into play in terms of human relations.
Indeed, Henry James thought Middlemarch 'too often an echo of
Messrs. Darwin and Huxley' [Galaxy 15 [1873]: 424-8). But, despite
her partner G. H. Lewes's deep interest in Darwin, particularly from
the mid-i86os on, George Eliot does not engage directly with his
work on the surface of her novels. Instead, she works with the forms
for experience that Darwin's theories imply: Who survives? How
does adaptation take place? What shapes can the unknown future
take? Is it possible to plan massive tribal change (as Daniel proposes
in the proto-Zionist conclusion of Daniel Deionda) 2 .
Much more manifestly responsive to the Origin is the work of
poets such as Mathilde Blind, Emily Pfeiffer, May Kendall, and Con-
stance Naden. Naden and Kendall wittily satirise current society
by means of evolutionary ideas. In 'The New Orthodoxy', Naden,
herself well educated scientifically, suggests that faith in science
has usurped religious faith as a mark of respectability: the young
woman speaker in the poem - a Girton girl - berates her suitor for
his backsliding from belief (in Darwin, not religion):
Things with fin, and claw, and hoof
Join to give us perfect proof
That our being's warp and woof
We from near and far win.
Yet your flippant doubts you vaunt,
And - to please a maiden aunt -
You've been heard to say you can't
Pin your faith on Darwin!
(Naden 1894, 313)
Mathilde Blind takes with formidable seriousness Darwin's vision
of descent. The appearance of The Descent of Man in 1871 trig-
gered considerably more immediate literary response than did the
initial publication of the Origin. It also enhanced the presence of the
Origin in later nineteenth- century literary controversy. Blind's one-
hundred-page-long epic poem The Ascent of Man first imagines the
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Lineal Descendants 291
primal stirrings of life ('Chaunts of Life') and then turns to the fate of
the outcasts, those who do not survive the evolutionary power strug-
gle ('The Pilgrim Soul'). The last section of the poem is 'The Leading
of Sorrow', where a veiled woman conducts the poet through all the
reaches of life and death subject to the evolutionary law of struggle
and survival. It was first published in 1889 and then again in 1899,
that time with a preface by Alfred Russel Wallace. He is shocked as
well as impressed by her sombre view of 'the destruction and war
ever going on in the animal world, from the lowest to the highest
forms' ( Blind 1899: ix). Blind magnificently evokes the energies of
primal growth:
Enkindled in the mystic dark
Life built herself a myriad forms,
And, flashing its electric spark
Through films and cells and pulps and worms,
Flew shuttlewise above, beneath,
Weaving the web of life and death.
(Blind 1899, 17)
Pfeiffer expresses the extreme disturbance of evolutionary expe-
rience in pithy sonnets. Evolution, she writes in the poem of that
title, is 'Hunger':
Hunger that strivest in the restless arms
Of the sea-flower, that drives rooted things
To break their moorings
(Pfeiffer 1888, 51)
Nature, meanwhile, in another sonnet in that sequence, has changed
from 'nursing mother' to 'Dread Force', 'Cold motor of our fervid
faith and song': 'Churning the Universe with mindless motion' (30).
Mark Pattison responded to Pfeiffer's poems with a shudder at the
'evolutional idea':
I think the most striking and original of your sonnets are inspired by the
evolutional idea - an idea or form of universal apprehension, which, like a
boa, has infolded all mind in this generation in its inexorable coil. Try as
we may, we cannot extricate our thoughts from this serpent's fold. (Pfeiffer
1888, iii)
So by the 1 8 80s Darwin's ideas have become inextricably wrought
into the thoughts of a generation. They can move beneath the surface
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292, GILLIAN BEER
without the need for direct allusion, inescapable. It is in that style
that Hardy responds to them in novels like Tess of the D'Uibeivilles
and Jude the Obscure. Tess, scion of an antique family, would
be happier remaining a lowly Durbeyfield than rediscovering past
D'Urberville grandeur: Trom the first growth of the tree, many a
limb and branch has decayed and dropped off [Origin, 129). Tess is
fruitful yet doomed because circumscribed by current social con-
ventions. Her physical generosity is exploited and misunderstood by
contrasting men, Alec and Angel. She seems to offer fecundity and
a wholesome future, but she is sacrificed to the demeaning assump-
tions of her environment. So energy becomes murder becomes sacri-
fice. Jude the Obscure is bleaker yet: here the general will to live is
withering, and Jude's struggles end in a death that is set to one side,
unnoticed. The future, as imagined in this novel, is blasted by the
division between the intellectual Sue and the grossly physical Ara-
bella. Sue recoils from sexual freedom. Arabella proves to be fittest
to survive in a degraded world.
Hardy took further Darwin's hint that natural selection may not
produce perfection (bees die as they sting, for example); he combined
that with the observation in The Descent of Man and Selection in
Relation to Sex that sexual selection among humans, in contrast
to other species, is driven by the social and economic power of the
male, to the detriment of the health of future generations because,
among other things, such men tend to select heiresses, who are likely
to come from low-fertility families. Hardy responded to Darwin's
work with all the intensity of a man who, like Darwin, noticed
the variant, the aberrant, and who questioned the normative. The
tenor of his work is darker than Darwin's may seem to be, but it is
faithful to the insights into waste, extinction, individual withering,
and the ravishing beauty of the natural world that are fundamental
to Darwin's vision, too.
In these later days of the nineteenth century, the Origin, with its
abstemious resistance to naming humankind, had become blended in
many people's minds with the more robust presence of the human in
the argument of The Descent of Man. And that is how it continued to
be for many years. One can observe the effects of this amalgamation
in the two works with which I now conclude. One might choose a
number of the novels of H. G. Wells to examine, notably The Time
Machine (1895), with its vision of a future in which the beautiful
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Lineal Descendants 293
Eloi seem to dominate but prove to be food for their degraded servant
class, the Morlocks:
But, gradually, the truth dawned on me: that Man had not remained one
species, but had differentiated into two distinct animals: that my graceful
children of the Upper- world were not the sole descendants of our generation,
but that this bleached, obscene, nocturnal Thing, which had flashed before
me, was also heir to all the ages. (Wells 1993, 47)
Wells had been a pupil of Thomas Henry Huxley and remained fas-
cinated by the implications of evolutionary theory. He saw, along
with his mentor, that the very distant future would see 'the life
of the old earth ebb away', leaving only silence, darkness, and one
strange thing 'hopping fitfully about' (86). But the work that bears
the full brunt of Darwin's arguments is The Island of Dr. Moreau
(1896).
This novel, much affected also by the late Victorian controversies
around vivisection, takes up Darwin's idea of the 'great family' in
which all life is kin and brutally demonstrates what happens when
surgical experiment replaces the slow process of natural selection.
In that sense it is very much on Darwin's side, and against 'artificial
selection' and, perhaps, eugenics. On a remote island the narrator
finds himself shipwrecked and at the mercy of two other English-
men, one of whom is carrying out viciously painful experiments that
graft species together: Hyaena-Swine and Bear Man. Moreau is a type
of the scientist without empathy, preoccupied solely with 'the study
of the plasticity of living forms' and refusing to recognise the suffer-
ing he imposes on living creatures. Moreau's dread is that the crea-
tures will breed and that they will gain a taste for meat. So the Beast
People are constrained by the Law, which they chant ritualistically
and which keeps them enthralled. Of course, the inhibitions fail,
in a rout of violence and treachery. This grim fable, like The Time
Machine, is now sometimes seen as having a racist element. But,
more powerfully, it can be read against the horrors of irresponsi-
ble experiment that benefits only sterile knowledge at the price of
diverse life.
A far more cheerful take on Darwin is the popular masterpiece
Tarzan of the Apes (19 14) by Edgar Rice Burroughs. Here the hero
Tarzan, son of an aristocratic young couple killed by the king ape,
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294 GILLIAN BEER
Kerchak, is brought up as an ape by his adoptive ape mother. Trou-
ble arrives with Jane, the human heroine whom Tarzan loves. The
book, with marvellous absurdity, produces a paradoxical ending that
affirms Tarzan's gentlemanly genetic inheritance. Tarzan (though
knowing by now his true parentage) tells Jane's fiance (Tarzan's own
cousin) that his mother was an ape and that she therefore could not
tell him about the family from which he stems. The 'great family',
in the sense of those with chivalric credentials, is put back in charge.
Jane marries her gentlemanly fiance, and Tarzan has to be content
with his own honourable behaviour in denying his descent as a man,
rather than as an ape. It is that disinterested denial that vouches for
his aristocratic birth. Indeed, the paradoxes stretch further, since the
cousin has discovered Tarzan's true birth and Tarzan comes to know
this; thus the behaviour of one brought up within the pale of high
human society is unfavourably contrasted with that of one brought
up among apes. Of course, this self-abnegation leaves Tarzan with-
out a mate, and so not a good example of survival. The gentleman
must bow out of the struggle for existence.
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NAOMI BECK
16 The Origin and Political
Thought
From Liberalism to Marxism
The publication of the Origin of Species propelled Darwin to the sta-
tus of a public figure, and although he himself preferred to remain
secluded in his country house at Downe and pursue specialised
research, his theory was at the centre of a heated debate on the
social and political implications of evolution. The key principles
of Darwin's biology - the struggle for existence and natural selec-
tion - became subject to a wide spectrum of interpretations rang-
ing from laissez-faire liberalism to Marxism. This state of affairs
raises some interesting questions concerning the claims and argu-
ments advanced by proponents of such opposing views in defence of
their positions. Simultaneously, one may inquire after Darwin's own
political opinions. This chapter proposes to examine these questions
through a close study of reactions to the publication of the Origin
from three different sources: first, the somewhat misleading enthu-
siasm of Herbert Spencer, the great philosopher of evolution and
an advocate of an extreme type of individualism; second, the pro-
gressive attitude of Clemence Auguste Royer, the first translator of
Darwin's Origin into French; and finally, the comments made by
the authors of the Communist Manifesto, Karl Marx and Friedrich
Engels. All three offer particularly interesting case studies, since
Darwin expressed his own opinions of their claims regarding his
theory, mostly in private correspondence. Thus, they provide not
only a window on the multifarious political uses made of Darwin's
biological proposals as put forth in the Origin, but also a way to
probe his own standpoint on matters political. Another advantage
of this pointed examination lies in its focus on the period prior to
the publication of The Descent of Man. Darwin avoided the ques-
tion of the origins of mankind in his 1859 publication for fear that
295
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296 NAOMI BECK
parading his views on the subject without any evidence would be
"useless and injurious to the success of the book" [Autobiography,
1 30-1). But his readers and contemporaries were much less hesi-
tant to venture into the dangerous territory. Thus, by limiting the
time frame to the decade of the 18 60s I hope to highlight Darwin's
concerns and to examine the tensions that the Origin had to face
upon publication. This approach will also help gauge the political
significance and impact of the theory of biological evolution before
Darwin decided to tackle directly the topics of man and his social
existence.
I begin my investigation with Herbert Spencer and a review of
his intellectual production prior to 1859, since it is necessary for
understanding his attitude vis-a-vis Darwin's work and vice versa.
During his lifetime, Spencer's reputation was as great as that of
his illustrious compatriot, and among the list of subscribers to
his most important work - the System of Synthetic Philosophy -
one can find the names of the main figures in Darwin's close cir-
cle: the geologist Charles Lyell, the botanist John Hooker, and the
biologist Thomas Henry Huxley. Spencer's glory, however, was not
destined to last long, and already toward the end of his life his evolu-
tionary theories were viewed as outdated and inaccurate. The goal of
Spencer's Synthetic Philosophy was to give a comprehensive account
of evolution and progress in both nature and society through a ten-
volume publication covering the fields of physics, biology, psychol-
ogy, sociology, and ethics. His main motive in this ambitious enter-
prise was primarily political and consisted of providing the doctrines
of liberal individualism and laissez-faire economics with a scientific
basis. This was evident as early as 1842, when Spencer published a
series of twelve letters entitled "On the Proper Sphere of Govern-
ment," in which he expounded the key elements of his evolutionary
theory. First, Spencer expressed his belief in a close and specific
relation between animate creatures (including man) and the exter-
nal world in which they lived, whereby each had appropriate organs
and instincts adapted for the performance of its life activities. These
activities, in their turn, were dependent upon the position in which
the creature was placed, since "Nature provides nothing in vain.
Instincts and organs are preserved only as long as they are required. "
Second, Spencer claimed that natural laws were universal and bal-
anced each other; and finally, he stated his strong opposition to any
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The Origin and Political Thought 297
form of government intervention because it hindered the natural
course of affairs, viz. the cobalancing action of universal laws. These
convictions, formed at the age of twenty-two, were to remain the
core of Spencer's subsequent theories, and, as he himself confessed
in his autobiography, without the letters "On the Proper Sphere of
Government" he would probably never have written the System of
Synthetic Philosophy (Spencer 1904, 1: 238-42).
Spencer greatly elaborated his political views in a first book, pub-
lished in 1 85 1 under the title Social Statics: or The Conditions Essen-
tial to Human Happiness Specified and the First of Them Devel-
oped. It was written while Spencer was employed as coeditor for
The Economist, a journal known for its open defence of laissez-faire
economics. As suggested by the subtitle, the principal goal of Social
Statics was to give an account of the rules appropriate to a purely
scientific moral system, one that would be based on the same uni-
versal laws that governed nature. Chief among them was the law of
equal freedom: "Every man has freedom to do all that he wills, pro-
vided he infringes not the equal freedom of any other man" (Spencer
1 85 1, 103 ). The existence of evil was explained as the result of a lack
of liberty in the exercise of faculties. Thus, in Spencer's view, the
moral law of equal freedom was simply the development of a physi-
ological truth. The rest of the treatise was dedicated to studying the
various corollaries of the law of equal freedom, such as the freedom of
speech, and drawing their political implications. These boiled down
to the affirmation that the state should interfere as little as possible
in the private affairs of its citizens, since whenever it attempted to
alleviate social suffering it actually created more misery. Accord-
ing to Spencer, by employing artificial measures the state meddled
with nature's mechanism; it assured the survival of that part of the
population that could not adapt to the conditions of existence, and
in doing so it obstructed progress and favoured instead a general
physical and intellectual degeneration. In the name of this strict
noninterventionism Spencer discarded all the legislative measures
destined to help the underprivileged, such as the poor laws and other
initiatives designed to improve the education and health systems.
After Social Statics, Spencer turned his attention to biology. Yet
it seemed as though his interest in this domain followed from his
political engagement and was due mainly to his wish to give a com-
prehensive account of evolution in nature and society, rather than
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298 NAOMI BECK
to a genuine interest in the natural sciences themselves. In 1852,
he published a short article entitled "The Development Hypothe-
sis," which was an open attack on creationism and a repudiation
of any appeal to supernatural forces in a truly scientific explana-
tion of the development of life. The biological knowledge used in
writing this piece came mainly from Charles Ly ell's Principles of
Geology. Paradoxically, it was Lyell's critique of Lamarck's trans-
formism that convinced Spencer of the validity of the French nat-
uralist's theory (Spencer 1904, 2: 7). There soon followed an article
entitled "A Theory of Population, Deduced from the General Law of
Animal Fertility," published in the same year. In this second article,
Spencer expounded on Thomas Malthus's theory concerning the gap
between arithmetic growth of natural resources and geometric mul-
tiplication of human beings, declaring that the pressure of population
increase is the proximate cause of progress. All men are subject to
its "discipline . . . they either may or may not advance under it; but
in the nature of things, only those who do advance under it eventu-
ally survive"; they are the "select of their generation." According to
Spencer, these statements brought him to the edge of the theory pub-
lished eight years later in Darwin's Origin (Spencer 1904, 1: 450-1).
In truth, however, Spencer's belief that evolution was driven by indi-
vidual competition and direct adaptive responses to changes in life
conditions was more in line with Lamarckism. Consequently, he
viewed the struggle for existence as the motor of progress, for it
prompted individuals to "advance" and become fitter, that is, to
develop useful habits and characters in order to survive in their envi-
ronments. Since only those who survived were able to reproduce,
new acquired traits were passed on to future generations, translat-
ing the effects of individual competition into general progress. It is
no wonder that Spencer's biological theories were particularly con-
ducive to his political convictions, and indeed in an article published
in 1857 under the revealing title "Progress: Its Law and Cause," he
ventured to incorporate his diverse views under one overarching
law. "Progress," he declared in what was to become the working
premise for his entire synthetic system, "is not an accident, not a
thing within human control, but a beneficent necessity" (Spencer
1892, 1: 60).
When Darwin's Origin appeared, Spencer welcomed it enthusias-
tically and confessed his satisfaction in reading the book (Spencer
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The Origin and Political Thought 299
1904, 2: 57). In reality, however, Spencer's eagerness to embrace
Darwin's theory was the result of his desire to incorporate it into
his own system of progress as yet another proof of the validity of the
universal law of development, without noticing the differences that
it presented with his Lamarckian position. This was manifest in the
arguments employed in Principles of Biology, a two-volume work
published between 1863 and 1867. In this work, Spencer defined
life as the continual adjustment of organisms to their milieus in
order to guarantee existence. He then proceeded to declare that the
main mechanisms governing this process were the laws of use and
nonuse and the principle of acquired characters. Given this line of
argumentation, it was clear that in Spencer's view Lamarckian func-
tional adaptation was the determining cause of the structure of living
things. Spencer saw natural selection not as the key to evolution but
as a secondary mechanism of elimination of those unfit for their
environment. Furthermore, random variations had no place in his
strictly causal explanation. Evolution was solely the result of the
responses of the organism to the changing conditions of its habitat,
and because these conditions did not necessarily affect all organ-
isms in the same manner, individuals of the same species would
differ from one another. Some were more apt to survive the strug-
gle for existence than others, and they were the ones that repro-
duced. Variations in structure were thus reduced to two categories -
good and bad - with natural selection simply having the function
of separating the fit from the unfit. Indeed, according to Spencer,
this process of evolution was better identified or could "more liter-
ally be called survival of the fittest" (Spencer 1904, 2: 11 5-16). A.
R. Wallace suggested to Darwin that he adopt Spencer's expression
instead of "natural selection," since the metaphorical character of
this latter seemed to personify nature or imply deliberate choos-
ing and "preferring" of the good of the species. "Survival of the
fittest," Wallace argued, could not be misunderstood in this way
because it was a more "compact and accurate" definition of the nat-
ural process of extermination of unfavourable variations. Wallace
added that using Spencer's expression would help differentiate
between two senses of natural selection that he detected in Darwin's
book: first, natural selection as the simple process of sifting between
variations, preserving only the favourable ones; and second, natu-
ral selection as the accumulated effect or change produced by this
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300 NAOMI BECK
preservation. Darwin agreed with Wallace, confessing that the merits
of "Spencer's excellent expression" had not occurred to him before,
and stated his intent to use it in future editions of the Origin. 1
He nonetheless expressed his doubts whether "the use of any term
would have made the subject intelligible to some minds" [More Let-
ters, i: 267-71). Spencer, so it seems, was one of those minds, since
Lamarckian functional adaptation continued to play the main role
in his theory of evolution. 2
Another essential point of difference between Spencer's and
Darwin's biological views concerns sexuality and its role in the
evolutionary process. Spencer postulated that there exists a direct
relationship between the degree of fertility and the level of men-
tal development of living beings. The more developed and complex
an organism, the higher its "expense" in terms of nervous influx
spent on perfecting its intelligence and ameliorating its situation.
The result is a diminution of its reproductive capacities, since the
sexual organs receive less nervous influx. According to this view,
the degree of individual development and the aptitude to produce
offspring stand in inverse proportion to each other. Nonetheless,
Spencer maintained that the advantage acquired in one domain was
not entirely offset by the loss in another, since the more developed
beings were also better adapted and therefore had a better chance to
come out as winners in the struggle for existence (Spencer 1865-67,
Part IV). In this way, the problem of a possible contradiction between
the efforts of the individual to optimise its own existence - so impor-
tant to Spencer's political credo - and the perpetuation of the species
was avoided. In fact, this view of sexuality combined with the prin-
ciple of "survival of the fittest" guaranteed that the species would
be maintained in its highest possible form, for only the "best," or
those most mentally developed and physically adapted, could repro-
duce. Evolution was therefore the promise of progress, and indeed,
for Spencer, these two expressions were completely interchangeable:
1 Darwin started using the expression "survival of the fittest" in the fifth edition
of the Origin, where Chapter 4 is titled "Natural Selection or the Survival of the
Fittest."
2 Spencer continued to advocate adaptive-progressive evolution even after this biolog-
ical explanation was strongly contested by neo-Darwinians like August Weismann,
who sought to do away with the Lamarckian vestiges in Darwin's doctrine. See the
Contemporary Review, nos. 63-4, 66 (1893-94).
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The Origin and Political Thought 301
"I say progress, but I ought to say evolution; for now the word is
introduced and begins to be used instead of progress" (Spencer 1904,
1:589).
The similarity between Spencer's views and those of the political
economist Adam Smith and the utilitarian thinker Jeremy Bentham,
both of whom are mentioned in Social Statics, is manifest. Spencer
also made explicit the importance of his family background in form-
ing his convictions, especially the education given by his uncle, a
figure known for his political support of free trade and minimal
state interference (Spencer 1904, 1: Part I; Duncan, 1: Chapters 1-2).
Throughout his life Spencer remained faithful to his early and rather
extreme interpretation of laissez-faire liberalism, even when a shift
in the stance of his own political party seemed to be taking place in
the 1880s, with the liberals accepting the necessity of certain social
reforms (Spencer 1884). Some have claimed that Darwin shared
many of Spencer's views on human and social progress and that he
also believed that evolution is a process of improvement, though its
main mechanism is natural selection rather than environmentally
and functionally induced modifications (Greene 1 981). It is also note-
worthy that Darwin came from a strong Whig tradition and was a
member of the prosperous bourgeoisie. But can it truthfully be said
that his description of natural selection as "daily and hourly scru-
tinising . . . , rejecting that which is bad, preserving and adding up
all that is good" and acting "only through and for the good of each
being" [Origin, 84) is equivalent to Spencer's theory of progress? Can
it be said that Darwin's biological proposals were also derived from
or subjected to his political inclinations? The claims advanced in the
Origin seem to indicate otherwise.
Clearly, for Darwin, evolution was not a teleological process tend-
ing upward in a linear mode toward a specific goal. Though he
claimed that it led "to the production of the higher animals," that
is, to those with a better-adapted organisation and thus having an
advantage in the struggle for life [Origin, 3 3 6-7, 490), it was nonethe-
less an open-ended process and did not entail progress as Spencer
understood it. Operating through random variations and divergence,
Darwin's evolutionary development could not have a specific and
predicted outcome or a political application like the one that dic-
tated the structure of Spencer's theory. Although Darwin referred
to Spencer a number of times in his works and confessed a certain
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302 NAOMI BECK
esteem for his efforts, in a telling passage in his autobiography he
specified that his biological reasoning was far removed from that
of the English philosopher and professed his mistrust of the rather
hasty generalisations made by Spencer.
After reading any of his books, I generally feel enthusiastic admiration for his
transcendent talents, and have often wondered whether in the distant future
he would rank with such great men as Descartes, Leibnitz, etc. about whom,
however, I know very little. Nevertheless I am not conscious of having
profited in my own work by Spencer's writings. His deductive manner of
treating every subject is wholly opposed to my own frame of mind. His
conclusions never convince me: and over and over again I have said to
myself after reading one of his discussions, - "Here would be a fine subject
for half-a-dozen years' work." His fundamental generalisations (which have
been compared in importance by some to Newton's laws!) - which I daresay
may be very valuable under a philosophical point of view, are of such a
nature that they do not seem to me to be of any strictly scientific use. They
partake more of the nature of definitions than of laws of nature. . . . Anyhow
they have not been of any use to me. {Autobiography, 108-9)
Further light may be shed on Darwin's political views and the
political significance of the Origin through an analysis of the pref-
ace to the first French translation by Clemence Auguste Royer, and
Darwin's reaction to it. Royer was a woman of independent mind and
one of the early advocates of feminism. She had been trained as a
secondary school teacher, but her great interest in science had led her
to read Lyell and Lamarck, as well as Malthus and other economists.
It is unclear how the arrangement for Royer to translate Darwin's
work was made; however, she obviously had an agenda of her own
in taking on this task. According to her biographer, J. Harvey, Royer
never saw herself as a science popularizer; her mission was to con-
struct a philosophy that would make the world comprehensible
using science as a tool. (Harvey 1997). As a result, Royer did not
simply translate Darwin's Origin, but added extensive notes, offered
some of her own corrections (Miles 1988), and changed its title
from On the Origin of Species by Means of Natural Selection to De
l'Origine des especes, ou des Lois du progres chez les etres organises
(On the origin of species, or the law of progress of organic beings).
More importantly, Royer added a long preface explaining her own
interpretation of Darwin's theory and detailing the implications of
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The Origin and Political Thought 303
his ideas for human evolution. The preface begins with an attack
both on religion and on the church's dogma and is followed by a
declaration of faith in reason and scientific progress, which set the
tone for the whole piece. Royer then proceeds to situate Darwin's
book as the continuation of Lamarck's theory and Enlightenment
philosophy. This affirmation appears to be particularly important
given Royer's own position, which shows a strong attachment to
Enlightenment ideals such as the belief that human progress is an
inevitability that follows naturally from the progress of science and
reason. The question remains: was this in line with Darwin's evolu-
tionary thinking?
Royer maintained that there was a "solidarity" between her views
and Darwin's and that, in fact, she had arrived at similar conclusions
to his on the succession and progressive evolution of living beings
independently, while giving a course on the philosophy of nature and
history in Lausanne during the winter of 1859. She further claimed
that the notes added in her translation of the Origin simply offered
developments of Darwin's theory or general summaries that recapit-
ulated its main claims in a more synthetic form. Yet Royer also con-
fessed that she may have "dared hypotheses" more than the English
naturalist. These hypotheses were clearly explicated toward the end
of the preface and concerned the political and moral consequences
in which "Mr. Darwin's theory is fecund." In a passage that echoes
Spencer's laissez-faire individualism, Royer argued against "exag-
gerated pity and charity" and the "unintelligent protection of the
weak," since they lead to an increase in suffering and a degeneration
of the race. This is because the weak slow down the strong who need
to support them, thus preventing the powerful elements of society
from developing and multiplying, which in turn causes a serious
obstacle to progress. Since, as she believed, men were unequal by
nature, Royer argued that in the political realm all doctrines that
aim to achieve equality were unrealistic and harmfully Utopian.
Instead, she claimed that evolutionary biology gave support to the
most unlimited individual liberty and free competition, which had
already proved themselves to be the means of progress in the bio-
logical domain, leading to the evolution of man from very simple
organisms. By the same token, Darwin's theory offered, according
to Royer, an absolute criterion by which to judge between what is
good and what is bad from a moral point of view, since the moral
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304 NAOMI BECK
law of any species is that which leads to its conservation, multipli-
cation, and progress. Royer concluded by cautioning the reader that
she could only hint cursorily at the political and moral consequences
of Darwin's theory in her preface, since these last would fill a whole
book (Darwin 1862, xii-xxxvii). She also announced her desire to
write such a book, a task she accomplished in 1869 with a study
entitled The Origin of Man and Societes.
When Darwin received the French version of his book he was
unpleasantly surprised by the liberties taken by his translator. He
wrote to J. D. Hooker, complaining: "Almost everywhere in the
Origin when I express great doubts she appends a note explaining
the difficulty or saying there is none whatever! It is really curious
to know what conceited people there are in the world." Darwin
was also displeased with Royer's preface and her sweeping declara-
tions that "natural selection and the struggle for life will explain
all morality, nature of man, politics etc etc!!!" And he continued:
"She makes some very curious and good hits and says she will pub-
lish a book on these subjects and a strange production it will be"
(Harvey 1997, 67-8). Darwin worried that Royer's preface and trans-
lation were affecting acceptance of his ideas in France, and he had
good reason to think so. Royer, for example, had translated "natu-
ral selection" as "election naturelle," which she claimed was better
suited to illustrate Darwin's meaning in French, but also seemed to
indicate an intelligent and deliberate choice. She defended her word-
ing by invoking the term "elective affinities" in chemistry, which
refers to "inorganic, dead and inert nature." She agreed, however,
to adopt the more widely diffused expression "natural selection" in
the second edition of her translation, which appeared in 1865. 3 The
addendum "laws of progress" was also removed from the title. The
1865 edition was accompanied by a new foreword that reiterated
many of Royer's views, namely, her attacks against the church and
religion and her admiration for eighteenth- century Enlightenment
philosophy with its celebration of reason. To counter criticism of
her melange of philosophy and science in the first preface, Royer
replied that she was a synthetic spirit who believed that all phenom-
ena in the world are connected. She did not retract her developments
of Darwin's ideas and in fact highlighted the liberties she had taken
3 For a different view on the subject see S. Miles (1988, 1: 42-5, 78-82).
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The Origin and Political Thought 305
in the translation. As for the political consequences she deduced
from Darwin's biology, Royer affirmed that she did not pretend that
Darwin accepted everything she dared to say and that it was not
her intention to jeopardise his theory. Finally, to quiet the rumours
that Darwin himself was displeased with her work, she claimed to
have letters in her possession stating the opposite (Darwin 1866,
viii-xiii, 95).
Darwin was dissatisfied with Royer's modifications and supple-
ments, especially the comments concerning the political and moral
implications of the theory of natural selection. Indeed, Royer's views
on evolution and progress appear to be closer to Spencer's than
to Darwin's, as does her defence of free competition and limited
state intervention. Like Spencer, she remained faithful to Lamarck's
transformism throughout her life, describing the French naturalist
as Darwin's forerunner and dedicating articles to his life and work
(Royer, 1868-69). Furthermore, in the new foreword written for the
third French edition of the Origin, Royer criticised Darwin severely
for his pangenesis theory, claiming that its archaic character and
clearly false assumptions endangered the theory of natural selection
(Darwin 1870, vi, xviii-xxvi). This attempt to sabotage his work was
the last straw for Darwin, and he decided to dissociate himself totally
from Royer and her opinions. He was also extremely displeased with
Royer for not having asked his permission to issue another edition
of her translation and for overlooking the corrections and notes that
he had included in the previous two English versions of the Origin.
He was determined, therefore, to ask for a new translator or with-
draw his authorisation. A solution was quickly found with another
Parisian editor, who published a translation of the fifth edition of the
Origin in competition with Royer's third edition. This was the end
of the correspondence between Darwin and Royer. It is nonetheless
worthwhile mentioning, as Harvey has pointed out, that Darwin
seemed interested enough in Royer's comments to include her book
on The Origin of Man and Society in a list of possible sources for his
own study of human evolution. As for Royer, she confessed to hav-
ing been unlucky with her book on human evolution: some copies
were published in 1869 and some in 1870, but the outbreak of the
Franco-Prussian War diverted public attention (Harvey 1997, 100-1 ).
Darwin's reaction to Royer's attempt to portray evolution as a pro-
gressive process, as well as his comments on Spencer's philosophy,
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306 NAOMI BECK
are revealing. Far from cautionary, his attitude was one of rejection
of any direct application of notions like the struggle for existence and
natural selection to the socioeconomic realm, a move he deemed to
be hasty and unwarranted. In this respect it is no coincidence that
both Spencer and Royer were inspired by Lamarck's transformism
and that the French naturalist's theory remained the chief influence
over their evolutionary thinking long after the publication of the
Origin. In reality, they were not adepts of Darwin's theory at all and
perhaps even ignored its most original aspects that did not sit well
with their political agendas. Simply put, Darwin's kind of evolution
could not be equated with progress in the sense of development in
a specific direction or toward a specific goal. Natural selection can
lead to radically different outcomes in different conditions; there is
nothing linear in its modus operandi, and as a result there can be
no hierarchy of weak and strong, good and bad. This was a major
difference between Darwin's science and Spencer's and Royer's evo-
lutionary conceptions.
It appears as though what eluded Spencer and Royer was specifi-
cally what attracted their counterparts on the other side of the politi-
cal spectrum: Karl Marx and Friedrich Engels. At first, the authors of
the Communist Manifesto seemed particularly impressed with the
lack of a predetermined telos in Darwin's theory of evolution. How-
ever, this too quickly changed, a sign that there is a more profound
difference between Darwin's enterprise and the underlying logic of
political discourses, as an analysis of Marx and Engels' reaction to
Darwin's theory will demonstrate.
A short time after the publication of the Origin, Engels wrote to
Marx: "Darwin . . . whom I'm reading just now, is absolutely splen-
did. There was one aspect of teleology that had yet to be demol-
ished, and that has now been done. Never before has so grandiose an
attempt been made to demonstrate historical evolution in Nature,
and certainly never to such good effect. One does, of course, have
to put up with the crude English method" [Collected Works, 40:
551). Engels's letter is dated less than three weeks after the Origin
appeared in bookshops in England, a fact that indicates his great
interest in Darwin's theory. Marx, on the other hand, waited a year
before replying to Engels on the topic. He agreed that although
Darwin's treatise on natural selection is developed "in the crude
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The Origin and Political Thought 307
English fashion, this is the book which, in the field of natural history,
provides the basis for our views." In fact, Marx drew an even closer
connection between Darwin's theory and his own doctrine in a let-
ter to Ferdinand Lassalle in 1861, declaring: "Darwin's work is most
important and suits my purpose in that it provides a basis in the
natural science for the historical class struggle" [Collected Works,
41: 232, 246-7). A closer examination shows, however, that Marx
and Engels did not share exactly the same views on Darwin's theory
and that their acceptance of the biological claims put forward in the
Origin was conditioned by powerful political motives, as noted by
Yves Christen (Christen 1987). In 1866, for example, Marx wrote to
Engels:
A very important work which I shall send on to you ... as soon as I have made
the necessary notes, is: P. Tremaux's Origine et transformations de l'homme
et des autres etres, Paris, 1865. In spite of all the shortcomings that I have
noted, it represents a very significant advance over Darwin. . . . Progress,
which Darwin regards as purely accidental, is essential here on the basis of
the stages of the earth's development.
This last remark refers to one of the main theses in the work of
French ethnologist, archaeologist, painter, and photographer Pierre
Tremaux, who claimed that the physical features and evolution of
the Earth determine the structure and modifications of living beings
and are the main cause of differentiation. Marx was particularly
impressed with Tremaux's declarations regarding man's total sub-
jection to the laws of nature. He confirmed that "in its historical
and political applications [the work of Pierre Tremaux is] far more
significant and pregnant than Darwin." Engels's opinion was quite
different. He wrote back to Marx that though he had not yet finished
reading Tremaux's work, he had "come to the conclusion that there
is nothing to his whole theory because he knows nothing of geol-
ogy, and is incapable of even the most common-or-garden literary-
historical critique. ... In addition, it is another pretty notion of his
to ascribe the differences between a Basque, a Frenchman, a Breton,
and an Alsatian to the surface-structure." Engels concluded with the
categorical verdict: "The book is utterly worthless, pure theorising
in defiance of all the facts, and for each piece of evidence it cites it
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308 NAOMI BECK
should itself first provide evidence in turn" [Collected Works, 42:
304-5, 320).
Engels's uncompromising attack did not cause Marx to alter his
view. In his response Marx evoked Cuvier, arguing that Engels's
judgment echoed almost word for word the French naturalist's criti-
cism of German theories on the variability of species. Yet scientific
progress had proved Cuvier to be wrong, and it turned out to be
"German nature-worshippers, amongst others who formulated Dar-
win's basic idea in its entirety, however far they were from being able
to prove it." Engels conceded that Darwin might not have insisted
enough on the influence of the soil in the evolution of organisms,
perhaps for lack of data. He nonetheless continued to maintain that
when Tremaux "goes on to declare that the effect of the soil's greater
or lesser age, modified by crossing, is the sole cause of change in
organic species or races, I see absolutely no reason to go along with
the man thus far, on the contrary, I see numerous objections to so
doing," namely, that 9/10 of his "ridiculous evidence" is based on
"erroneous or distorted fact" [Collected Works, 42: 322-4). This was
the end of the exchange between Marx and Engels on the subject, and
it seems as though they remained divided in their opinions, for only
a few days after Engels's last letter Marx sent a letter to his friend
Ludwig Kugelmann recommending Tremaux's book and insisting
that "although written in a slovenly way, full of geological howlers
and seriously deficient in literary-historical criticism, it represents -
WITH ALL THAT AND ALL THAT - an advance over Darwin"
[Collected Works, 42: 327). Marx's appraisal of Tremaux is interest-
ing if only because it enables us to better understand his position
vis-a-vis Darwin's evolutionary theory. His insistence on the all-
importance of the soil in explaining evolutionary changes reveals
a strong attachment to a causal determinism of environmental
conditions that is more in tune with Lamarck's views than with
Darwin's biology. After all, Lamarck's view of evolution was bet-
ter suited to Marx's claims concerning the overriding importance of
material conditions of existence in determining the nature of indi-
viduals as well as their intellectual and social existence, professed
two decades earlier in his critique of German ideology. These claims
subsequently became the building blocks for Marx's materialist con-
ception of history and therefore could not easily have been modified
or reworked.
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The Origin and Political Thought 309
Marx may have also leaned toward a favourable appreciation of
Tremaux's theory because of the latter's claim that the Darwinian
struggle for life can have only negative results for both survivors
and losers. According to Tremaux, when animals and plants fight
with each other for the same living space they are all weakened
by the fierce competition and as a result degenerate rather than
develop and progress (Christen 1981, 58). Marx himself condemned
the mechanism of the struggle for existence when he wrote to Engels
in an often-quoted letter from 1862:
I'm amused that Darwin, at whom I've been taking another look, should
say that he also applies the 'Malthusian' theory to plants and animals, as
though in Mr Malthus's case the whole thing didn't lie in its not being
applied to plants and animals, but only - with its geometric progression -
to humans as against plants and animals. It is remarkable how Darwin
rediscovers, among the beasts and plants, the society of England with its
division of labour, competition, opening up of new markets, 'inventions'
and Malthusian 'struggle for existence'. It is Hobbes' helium omnium contra
omnes and is reminiscent of Hegel's Phenomenology, in which civil society
figures as an 'intellectual animal kingdom', whereas, in Darwin, the animal
kingdom figures as civil society. [Collected Works, 41: 381)
Engels, on the other hand, tried to overcome the problematic aspect
of Darwin's Malthusianism by arguing for a discrepancy between the
evolution of man and the evolution of animals. "I, too," he wrote in
1865,
was immediately struck on first reading Darwin by the remarkable similar-
ity between his description of the vegetable and animal life and the Malthu-
sian theory. Only my conclusion was . . . that it is to the everlasting disgrace
of modern bourgeois development that it has not yet progressed beyond the
economic forms of the animal kingdom. The so-called 'economic laws' are
not eternal laws of nature but historical laws that appear and disappear, and
the code of modern political economy, insofar as the economists have drawn
it up correctly and objectively, is for us merely a summary of the laws and
conditions in which modern bourgeois society can exist. [Collected Works,
42: 136)
When the first volume of Marx's Das Kapital appeared Engels
was able to reconcile his admiration for Darwin's science - minus
the latter's adherence to Malthus - with his loyalty to Marx's ideas
by proclaiming his good friend as the first thinker to truly grasp the
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310 NAOMI BECK
meaning of evolution in the human domain. He heralded Marx's con-
tribution to the study of economics as the most important scientific
innovation in the field, indeed as comparable to Darwin's achieve-
ment in the realm of biology: "In so far as he [Marx] endeavours to
show that present-day society economically considered, is pregnant
with another, higher form of society, he merely strives to present as
law in the social sphere the same process which Darwin traced in
natural history, a process of gradual evolution" [Collected Works,
20: 224-5). This statement was intended to establish Marx's inde-
pendent scientific status as Darwin's equal, rather than to portray
him as a follower or disciple. In other words, according to Engels,
whereas Darwin was able to reveal to us the truth about the organic
world, he could not take us further. Marx was the one who finally
uncovered the truth about human evolution in all its complex eco-
nomic, social, and political relations. In this manner Engels was able
to assuage his dissatisfaction with the political views that inspired
Darwin's biology and at the same time to affirm Marx's revolutionary
conclusions. In short, his strategy amounted to putting each thinker
in charge of a different sphere of knowledge: "Just as Darwin discov-
ered the law of development of organic nature, so Marx discovered
the law of development of human history. . . . Such was the man of
science. But this was not even half the man. Science was for Marx a
historically dynamic, revolutionary force ..." [Collected Works, 24:
467-8).
These words, pronounced at Marx's graveside, seem to summarise
well the difference between the two thinkers. Marx's objective could
not have been further from Darwin's. His goal was to change the
world, not to interpret it in a different way, while Darwin wanted to
understand nature through careful observation. This is perhaps why
Darwin was not particularly interested in Marx's study of capitalism.
Only the first 102 pages of the 822 that comprise the German copy of
Das Kapital, which Marx sent Darwin as his "sincere admirer," were
cut, and they do not contain Darwin's customary comments (Gruber
19 6 1, 582). Darwin's polite response was very short, yet under the
humble mask of his supposed lack of education he made a point of
highlighting the distance that separated him from Marx: "I heartily
wish that I was more worthy to receive it [Marx's "great work on
Capital"], by understanding more of the deep and important subject
of political Economy. Though our studies have been so different, I
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The Origin and Political Thought 311
believe that we both Earnestly [sic] desire the extension of Knowl-
edge. . . " (Feuer 1975, 2). That Marx allegedly proposed to dedicate
Das Kapital to Darwin as a sign of respect and appreciation has
been proven false. Darwin's letter of refusal was actually destined
for Edward Aveling, Marx's son-in-law and the translator of the first
volume of Capital, who asked Darwin to endorse his secular, athe-
istic views as expressed in a compilation of his tracts bearing the
general title The Student's Darwin (Feuer 1975, 1-12; Carroll 1976,
384-94)-
Marx quoted Darwin twice in Capital, but he did so without giv-
ing any real weight to the principle of natural selection, focusing
instead on adaptation. The two footnotes in Chapters 14 and 15
constitute the only public mentions Marx made of Darwin's work
(Christen 1981, 66-7). These notes refer to Darwin's comments in
the Origin on the formation of organs in plants and animals as instru-
ments that may be adapted to very specific functions through natural
selection [Origin, 149). For Marx, these comments were of particular
significance because he claimed that the "history of Nature's Tech-
nology," as expounded by Darwin, should be complemented by the
"history of the productive organs of man, of organs that are the mate-
rial basis of all social organisation" [Collected Works, 35: 346, 375).
But this type of evolutionary thinking (i.e., that organs are adapted
to certain ways of life) was not particular to Darwin, nor was it
the source of his originality. It seems that Marx referred to Darwin
mainly because his was the most recent scientific work on evolution,
not because he judged it more favourably than other, lesser-known
treatises, like Tremaux's book. Engels's comments in the 1 870s indi-
cate the same attitude: "Of Darwin's doctrine, I accept the theory of
evolution, but assume Darwin's method of verification (STRUGGLE
FOR LIFE, NATURAL SELECTION) to be merely a first, provisional,
incomplete expression of a newly discovered fact." He continued to
specify in the same letter from 1875 that "if a self-styled naturalist
takes it upon himself to subsume all the manifold wealth of histor-
ical development under the one-sided and meagre axiom 'struggle
for existence', a phrase which, even in the field of nature, can only
be accepted cum grano salis, his method damns itself from the out-
set" [Collected Works, 45: 106-7). Engels also seemed to tilt toward
a more Lamarckian view of biological evolution when he claimed
in his 1878 publication Anti-Duhring that Darwin attributed to his
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312 NAOMI BECK
discovery of natural selection "too wide a field of action/' making it
the sole agent in the alteration of species and neglecting the causes
of "repeated individual variations" [Collected Works, 25: 65-6).
Engels's change of heart and disavowal of the main mechanisms
of Darwin's theory, together with Marx's reluctance to acknowledge
their role in evolution, show that in the case of Marxism, as in
the previously examined laissez-faire views of Spencer and Royer,
the similarities between Darwin's ideas and their ideological dis-
course were only superficial. In fact, this seems to have been
Darwin's own opinion. In a letter from 1879 to E. Haeckel, his most
prominent follower in Germany, Darwin expressed his full support
of Haeckel's rejection of any direct transfer of the theory of evolu-
tion into the realm of practical politics, specifically in support of
socialism (Richards 2008). Thus, a difference in kind between sci-
ence and politics becomes apparent, one that Darwin was aware of.
Political theories, by their very nature, have to be normative, since
they aim to convince the listener or reader that the solution offered
is beneficial, or at least more desirable than the existing alternatives.
Therefore, by definition, they need to have a specific objective, be
it a more equitable or prosperous society, a freer society, or some
other goal. Darwin's biology was constructed in response to a differ-
ent set of rules, those of scientific investigation and explanation. In
this sense it was not normative but descriptive. Darwin was as far
removed from Marx's claim that we must change the world as he
was from Spencer's and Royer's advocacy of laissez-faire liberalism
as the best social structure. His theory of evolution could not be
said to postulate progress toward a particular goal, for it depicted a
process of constant change involving numerous factors. He looked
to the past and the present as a way to understand the workings
of nature, not as a means for controlling it or predicting future
outcomes. Humbly, he declared in the concluding paragraph of the
Origin: "There is grandeur in this view of life, with its several pow-
ers," whereby "from so simple a beginning endless forms most beau-
tiful and most wonderful have been, and are being, evolved" ( Origin,
490). This is why he was reluctant to draw the political conclusions
of his findings; quite simply, he may have felt that he lacked the
tools and the data to judge one way or the other. In any case, his bio-
logical theory as developed in the Origin could not be of any help to
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The Origin and Political Thought 313
him in this domain. As for the proponents of laissez-faire liberalism
and Marxism we have examined here, it appears as though Darwin's
theory fulfilled for them only the function of a pretext and was not in
reality connected with their views, nor could these latter be inferred
from it.
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TIM LEWENS
17 The Origin and Philosophy
I. DARWIN AND DARWINISM
Darwinism is all the rage in philosophy these days. Evolutionary
thinking of one kind or another is frequently used to illuminate
such areas as ethics (e.g., Joyce 2006), epistemology (e.g., Hull 1988),
and the philosophy of mind (e.g., Sterelny 2003). But it is one thing
to examine how evolutionary work in a broadly Darwinian style has
influenced philosophy, another to ask what form of philosophical
insight is present in Darwin's own oeuvre. And it is something else
yet again to ask what the specific relationship might be between
philosophy and the Origin of Species. This last question can be bro-
ken down into an analysis of the work's philosophical legacy and an
analysis of its philosophical content.
Since the Origin has so often been taken by later thinkers as the
canonical statement of a Darwinian worldview, any project of assess-
ing that book's philosophical legacy risks sliding toward a hope-
lessly ambitious attempt to embrace all those subsequent forms of
philosophical Darwinism that the Origin has inspired. This essay
consequently focuses on the Origin's own philosophical content. In
the next section I will catalogue some of the philosophical themes
that arise in it. The third section contains some brief reflections on
Darwin's philosophical method. Section four addresses the Origin's
major philosophical input, namely, the scientific methodology of
This chapter draws heavily on scattered material from Lewens (2007). I am grateful
to the editors for inviting me to contribute to this Companion, and I am especially
grateful to Robert Richards, whose acute comments on an earlier draft saved me from
some embarrassing mistakes.
314
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The Origin and Philosophy 315
John Herschel. And the final two sections examine what, in the
eminent biologist Ernst Mayr's eyes, was the Origin's major philo-
sophical output - the shift from so-called typological thinking to
'population' thinking.
II. DARWIN AS PHILOSOPHER
Darwin's assessment of his own philosophical abilities is unpromis-
ing. In his autobiographical reminiscences, he claims that '[m]y
power to follow a long and purely abstract train of thought is very
limited; I should, moreover, never have succeeded with metaphysics
or mathematics' [Autobiography, 140). In spite of this alleged handi-
cap, Darwin took an active interest in philosophy. In the years imme-
diately after the return of the Beagle to England, he filled notebooks
with ideas whose descendants would appear in modified form in the
Origin and other works. During this period he read books by the
philosophers David Hume and Adam Smith, by the leading method-
ologists of science John Herschel and William Whewell, and by other
philosophers better known then than they are now, such as James
Mackintosh.
Darwin's notebooks are consequently rich in observation and
speculation regarding many of the same topics that today's philoso-
phers have attempted to view in an evolutionary light - the forma-
tion of our moral sense, the nature of emotional expression, the ori-
gins of innate knowledge, and so forth. Darwin's thoughts on these
topics appeared in published form in his later works, written well
after the Origin. It seems likely that Darwin wished to establish
the credentials of his basic transmutationist views prior to devel-
oping in print any extrapolation toward philosophical matters. The
value of this form of caution is illustrated by the hostile reception
that greeted another transmutationist work, the anonymously pub-
lished Vestiges of the Natural History of Creation, which appeared
in 1844 (fifteen years before the Origin). Vestiges was exceptionally
ambitious, covering everything from the origins of the universe as
a whole to the differences between men and women. The men of
science whom Darwin held in the highest esteem dismissed it as
speculative nonsense, and dangerous nonsense to boot. The Origin
was altogether a more serious affair, and Darwin worked hard at
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presenting its theory in a sober manner. He offered a wide variety
of data to support transmutationism, and he largely restricted his
discussion of the theory's application to the topics of speciation and
adaptation in plants and animals.
In spite of this, it would be a mistake to regard the Origin as wholly
silent on issues of broad philosophical significance such as divine
design, the mind, and morality. Most obviously, the book provides
a defence of transmutationism against special creation. Although
Darwin was no atheist when the Origin was written, he nonetheless
tackles directly the issue of whether it is necessary to invoke a
Creator to explain the immediate origin of species, concluding that
such explanations are vacuous: 'It is so easy to hide our ignorance
under such expressions as the "plan of creation," "unity of design,"
&c, and to think we give an explanation when we only restate a
fact' [Origin, 481-2).
The Origin's exploration of the action of natural selection on ani-
mal instincts also demonstrates Darwin's view that his theory can
shed light on the mind. Although these ideas were not applied to our
own species until the publication of The Descent of Man, Darwin
leaves his reader in no doubt about the potential of his theory in this
domain:
In the distant future I see open fields for far more important researches. Psy-
chology will be based on a new foundation, that of the necessary acquire-
ment of each mental power and capacity by gradation. Light will be thrown
on the origin of man and his history. [Origin, 488)
Darwin's remarks on the evolution of instincts in animals also hint
at his later work in Descent on the origins of the moral sense. In
Descent, Darwin argues that the good of the community should be
identified as the 'criterion' of morality (for discussion, see Richards
1987). That is to say, Darwin claims that what makes an action right
is its contributing to the good of the community, defined as 'the
means by which the greatest possible number of individuals can be
reared in full vigour and health, with all their faculties perfect, under
the conditions to which they are exposed' [Descent, 98). The case he
makes rests in part on his view that natural selection at the com-
munity level can explain how social instincts come to exist. These
instincts produce behaviour that promotes the community good.
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The Origin and Philosophy 317
This set of views is partially prefigured in the Origin - for example,
when Darwin suggests that:
It may be difficult, but we ought to admire the savage instinctive hatred of
the queen-bee, which urges her instantly to destroy the young queens her
daughters as soon as born, or to perish herself in the combat; for undoubtedly
this is for the good of the community,- and maternal love or maternal hatred,
though the latter fortunately is most rare, is all the same to the inexorable
principle of natural selection. [Origin, 202-3)
We ought to admire the queen bee's hatred, says Darwin, because
that hatred is for the good of the bees' community.
III. THE ORIGIN AND PHILOSOPHICAL METHOD
So far I have tried to show only that Darwin was interested in philo-
sophical topics, and that he regarded them as important enough to
introduce various hints in the Origin regarding the philosophical
promise of his theory. The Origin is also a useful text for demon-
strating a little about Darwin's views regarding proper philosophical
method. Remember that Darwin claimed to have been no good at
following 'a long and purely abstract train of thought'. I suggest
that this comment was somewhat disingenuous. Darwin proudly
described the Origin itself as 'one long argument' [Autobiography,
140): he was perfectly capable of keeping a long train of thought on
the rails. The Origin's argument is, of course, peppered with hard-
won empirical data, and Darwin's other remarks suggest that any
difficulty he may have suffered in coping with lines of thinking that
are 'purely abstract' rested as much on his scepticism regarding the
value of fact-free enquiry as on his cognitive limitations. Consider,
for example, that Darwin was disappointed when he reread his own
grandfather's proto-evolutionary work Zoonomia, 'the proportion of
speculation being so large to the facts given' [Autobiography, 49). Of
Herbert Spencer he said:
After reading any of his books, I generally feel enthusiastic admiration for
his transcendent talents, and have often wondered whether in the distant
future he would rank with such great men as Descartes, Leibnitz, etc., about
whom, however, I know very little. Nevertheless I am not conscious of hav-
ing profited in my own work by Spencer's writings. His deductive manner
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of treating every subject is wholly opposed to my frame of mind. His con-
clusions never convince me: and over and over again I have said to myself,
after reading one of his discussions, - 'Here would be a fine subject for
half-a-dozen years' work.' [Autobiography, 108-9)
The high regard in which Darwin is held among modern philoso-
phers is undoubtedly due in large part to the multipurpose explana-
tory power many attribute to the idea of natural selection. But,
as these comments suggest, Darwin also shares a methodological
stance with modern-day 'philosophical naturalists' who stress the
need for close attention to the results of the natural sciences in
order to discipline and inspire philosophical inquiry.
Darwin's empiricism does not make him wholly sceptical of the
value of armchair pastimes beloved of more traditionally minded
philosophers, such as the fabrication of thought experiments, and
abstract reflection on the meanings of terms. The Origin includes
several highly idealised scenarios intended to illustrate how, in broad
terms, aspects of Darwin's theory are meant to work. He requests
our indulgence, for example, as he explains the workings of natural
selection:
In order to make it clear how, as I believe, natural selection acts, I must beg
permission to give one or two imaginary illustrations. [Origin, p. 90)
Darwin then shows us how natural selection accounts for adaptation
by helping himself to a stylised example of a population of wolves
that lives by hunting deer. Darwin is aware, however, that a com-
bination of further reasoning and further evidence concerning such
matters as the character of variation in nature, the extent of resem-
blance between parents and offspring, and the nature of the struggle
for existence is required in order to show that natural selection is
in fact responsible for organic change, either generally or on specific
occasions. A famous paragraph at the end of Chapter 4 of the Origin
[Origin, 126-7), which summarises the argument for natural selec-
tion's existence and efficacy in largely abstract terms, is immediately
followed by a reminder that the case in favour of this principle is not
yet complete:
Whether natural selection has really thus acted in nature, in modifying and
adapting the various forms of life to their several conditions and stations,
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The Origin and Philosophy 319
must be judged of by the general tenour and balance of evidence given in the
following chapters. [Origin, 127)
The importance of pinning down the scope and form of natural selec-
tion also drives Darwin to clarify the meanings of the terms he uses.
He takes pains to point out, for example, that the 'struggle' for exis-
tence is meant in a 'large and metaphorical sense' that does not
require literal battles over resources, and that a plant 'may truly be
said to struggle with the plants of the same and other kinds which
already clothe the ground' [Origin, 62-3 ). In these cases, Darwin's use
of imaginary illustration and conceptual clarification is essential for
the articulation of the central explanatory schemata of his new the-
ory. When discussing other topics, he sometimes regards excursions
into similarly abstract matters as unnecessary, or distracting. At var-
ious points in the Origin, and throughout its later editions, Darwin
makes an effort to clarify the meanings of 'progress'. But consider
these remarks on what it might mean to say that one organism is
'higher' than another:
The embryo in the course of development generally rises in organisation: I
use this expression, though I am aware that it is hardly possible to define
clearly what is meant by the organisation being higher or lower. But no
one will probably dispute that the butterfly is higher than the caterpillar.
[Origin, 441)
Here, Darwin seems content with the thought that even if we
cannot say with clarity what is meant by 'height' of organisation,
we can at least recognise rising organisation when we see it. Or con-
sider his views on classification. Darwin argues that a genealogical
classification is the best one. On Darwin's view, organisms with
shared ancestry tend to resemble each other in many respects, both
trivial and important. This means that a genealogical classification
will also group together organisms that resemble each other most
closely:
In classing varieties, I apprehend that if we had a real pedigree, a genealogi-
cal classification would be universally preferred. . . . For we might feel sure,
whether there had been more or less modification, the principle of inher-
itance would keep the forms together which were allied in the greatest
number of points. [Origin, 423)
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This leaves open the question of whether the ultimate goal of clas-
sification is to give an accurate genealogy or to group organisms
by resemblance. So long as Darwin is right to say that genealogy
and resemblance ('filiation' and 'affinity', as he sometimes says) reli-
ably go together, practical taxonomic projects do not require that we
answer this question. But one can ask various 'what if?' questions.
What would happen if genealogy and resemblance were to come
apart? Isn't it logically possible that two organisms could resem-
ble each other very closely in many trivial respects without this
being attributable to inheritance from a common ancestor? What if it
turned out, for example, that just one of the many species of kangaroo
were descended from bears? How should that species be classified?
Darwin's genealogical system would demand that it be grouped with
the bears. But shouldn't we then violate Darwin's genealogical rule
and classify all the other kangaroo species with bears, too? Or are we
to say, absurdly, that only one kangaroo species should be classed
with the bears, no matter how much it resembles the other species
of kangaroo? Darwin has no truck with this sort of objection:
I might answer by the argumentum ad hominem, and ask what should
be done if a perfect kangaroo were seen to come out of the womb of a
bear? . . . The whole case is preposterous,- for where there has been close
descent in common, there will certainly be close resemblance or affinity.
{Origin, 425)
This counterexample, Darwin thinks, is too silly to be worth con-
sidering, and because of that it gives us no reason to revise his view
of classification (Lewens 2007, 80). Here, again, Darwin has allies
among some modern philosophers who refuse to let far-fetched imag-
inings undermine a serviceable theory.
IV. THE ORIGIN AND SCIENTIFIC METHOD
One of the most important philosophical inputs to Darwin's work
lies in the contribution of a particular view about scientific method
to Darwin's structuring of the Origin. It is tempting to cast the
Origin's argument as a form of 'inference to the best explanation'.
There is no doubt that in day-to-day reasoning we often infer that
theories are true by virtue of the fact that were they true, they would
best explain some body of data (Lipton 2004). This is typically the
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The Origin and Philosophy 321
case in forensic reasoning, where the identity of the murderer is
established by pointing out how the evidence is most neatly tied
together on the assumption that it was Professor Plum who did it.
In the final chapter of the Origin, Darwin summarises the varied
facts his theory is able to explain - facts about anatomy, embry-
ology, the distribution of species around the globe, even about the
characteristic arguments among natural historians - and he notes
how ill-equipped are rival theories to explain the same facts. In the
Origin's sixth edition he adds that:
It can hardly be supposed that a false theory would explain, in so satis-
factory a manner as does the theory of natural selection, the several large
classes of facts above specified. It has recently been objected that this is an
unsafe method of arguing; but it is a method used in judging of the common
events of life, and has often been used by the greatest natural philosophers.
[Variorum, 748: i83.I:f)
In other words, the fact that a theory is able to explain diverse phe-
nomena successfully is, Darwin thinks, strongly indicative of the
theory's truth.
Inference to the best explanation' (IBE) is an attractive slogan,
and it has considerable intuitive appeal. Even so, there are plenty
of hypotheses that have many of the marks of a good explanation,
which we are inclined to regard as false. Conspiracy theories often
neatly tie up bodies of diverse data, but they are nonetheless greeted
with scepticism. The defender of IBE would need, ideally, to give
some account of what features make an explanation good, and an
account of why the 'best' explanation in this sense is likely to be
true. Any such defence will face an uphill struggle. Suppose, for
example, IBE's defender claims that good explanations tend to be
simple explanations. In addition to answering the tricky question of
what is meant by 'simplicity', he would also need to say why the
simplest explanation is likely to be the right one. There is, after all,
no obvious a priori reason to think the universe must be a simple
place, and plenty of a posteriori reasons to think it is not.
I do not propose to give any general defence of the reliability of IBE
here. Instead, I will try to show that some versions of IBE are obvious
nonstarters, and that John Herschel's methodology of science - the
methodology followed by Darwin in the Origin - can be understood
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as a more sophisticated, more defensible form of IBE (Lewens 2007,
Chapter 4).
One might think that a good explanation is one that, were it
true, would make our data probable. Yet IBE is obviously hopeless
if it asserts that a theory need do nothing more than make our data
probable in order for us to be warranted in believing it. One problem
with this view is that it leads to absurd results. If Gordon Brown
were a Martian, then (since he would also be a living organism) it is
probable that he would have a metabolism. However, if we observe
that Gordon Brown has a metabolism, this clearly does not warrant
our inferring that he is a Martian. This version of IBE is also incom-
plete. Different, incompatible theories often entail, and thereby
make probable, many of the same observational consequences. The
hypothesis that Gordon Brown is a human also makes it probable
that he has a metabolism, but not even Brown can be both a Martian
and a human at once. So a plausible version of IBE needs to offer
some resources for choosing between competing theories when the
observations we are seeking to explain are common consequences
of all of them.
John Herschel was an astronomer and mathematician, and one of
the leading intellectual figures in Cambridge during the time Darwin
spent there as a student. Herschel also wrote on scientific method -
a topic that is often regarded today as part of philosophy. The two
men got to know each other after Darwin graduated from Cambridge,
meeting for the first time when the Beagle stopped off in South
Africa. Darwin respected Herschel enormously:
I felt a high reverence for Sir J. Herschel, and was delighted to dine with him
at his charming house at the C. of Good Hope and afterwards at his London
house. I saw him, also, on a few other occasions. He never talked much, but
every word which he uttered was worth listening to. {Autobiography, 107)
Darwin read Herschel's major methodological work during his stu-
dent days, and he credits it with having a great impact on his thought
(for detailed discussion of Herschel and Darwin, see Ruse 1975,
Hodge 1977, and Waters 2003):
During my last year at Cambridge I read with care and profound interest
Humboldt's Personal Narrative. This work and Sir J. Herschel's Introduc-
tion to the Study of Natural Philosophy stirred up in me a burning zeal to
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The Origin and Philosophy 323
add even the most humble contribution to the noble structure of Natural
Science. No one or a dozen other books influenced me nearly so much as
these two. [Autobiography, 68-9)
Herschel argues that a respectable scientific theory should appeal
only to 'true causes', or verae causae. Herschel understands that if
we are to place confidence in an explanatory theory, it is not enough
for that theory to posit causes that make sense of a single, narrow
range of phenomena. Further conditions must be satisfied. One of
these involves an extension of the explanatory range of a theory.
Herschel argues that our confidence should increase if a theory is
able to explain several distinct classes of phenomena. This aspect
of Herschel's methodology is reflected in Darwin's efforts to show
that his theory of descent with modification can account for diverse
facts in domains as varied as embryology, morphology, and biogeog-
raphy. Herschel also argues that we should have direct experience,
either of the posited cause itself or, failing that, of something closely
analogous to it. This feature of Herschel's thinking is reflected in
Darwin's efforts to demonstrate both that natural selection is real -
that offspring do resemble parents, that variation is plentiful, that
there is a struggle for life - and that the analogous force of artificial
selection has known efficacy in modifying species.
I do not mean to show that Herschel's methodological principles
are justified, but they do have a reasonable descriptive fit with the cri-
teria we use for theory choice. The hypothesis that Gordon Brown is
a Martian is not one that we should take seriously, if it does nothing
more than explain his possessing a metabolism. But we might take
it more seriously if it explained many diverse facts about Brown's
constitution and behaviour, and we would take it more seriously
still if we had direct experience of the existence of Martians.
The Origin's argument can be understood as an inference to the
best explanation. Darwin's adherence to Herschel's vera causa stan-
dard means that Darwin's sophisticated version of IBE avoids the
most obvious objections to this mode of argument. This is impor-
tant, in part because modern-day Intelligent Design (ID) theorists
sometimes appeal to IBE to ground their inferences from the struc-
ture of particular organic traits to a creative intelligence. But ID
theorists are typically far less sensitive than Herschel to the perils
of simplistic versions of IBE. A powerful designing intelligence is
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sometimes posited merely on the grounds that were there to be such
a thing, it would make probable the existence of an otherwise puz-
zling phenomenon, namely, the phenomenon of adaptation. This,
we have seen, is an indefensible mode of argument.
V. FROM TYPOLOGICAL THINKING
TO POPULATION THINKING
The eminent biologist and historian of biology Ernst Mayr argues,
in the introduction he wrote in 1964 to a facsimile edition of the
Origin, that contained within that book was a new and revolutionary
philosophical conception of nature. It represented nothing less than
the rejection of a thereto dominant Platonism:
The Origin of Species was far more than a mere accumulation of facts
proving evolution. . . . Darwin started from a new basis by completely elim-
inating the last remnants of Platonism, by refusing to admit the eidos (Idea,-
type, essence) in any guise whatever. (Mayr 1964, xi)
The specific philosophical breakthrough for which Darwin was
responsible is, says Mayr, the transition from a form of Platonism
called 'typological thinking' to a new way of thinking about nature,
which Mayr calls 'population thinking'. Mayr regards the introduc-
tion of population thinking into biology as Darwin's third great con-
ceptual innovation, at least as important as the hypothesis of the
evolutionary relatedness of species, and the articulation of natu-
ral selection as the primary mechanism of organic change. Mayr
described the typological/population distinction in different ways
through his career (Chung 2003), but by far the best-known formu-
lation comes from a paper originally published to mark the Origin's
centennial in 1959. The typologist is one who, in a manner reminis-
cent of Plato, posits an ideal specimen or 'form' for each biological
species:
According to [typological thinking], there are a limited number of fixed,
unchangeable 'ideas' underlying the observed variability, with the eidos
(idea) being the only thing that is fixed and real, while the observed variabil-
ity has no more reality than the shadows of an object on a cave wall, as it is
stated in Plato's allegory. The discontinuities between these natural 'ideas'
(types), it was believed, account for the frequency of gaps in nature . . . Since
there is no gradation between types, gradual evolution is basically a logical
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impossibility for the typologist. Evolution, if it occurs at all, has to proceed
in steps or jumps. (Mayr 1976, 27)
Darwin, by contrast, is a population thinker:
The assumptions of population thinking are diametrically opposed to those
of the typologist. The populationist stresses the uniqueness of everything in
the organic world. . . . All organisms and organic phenomena are composed
of unique features and can be described collectively only in statistical terms.
Individuals, or any kind of organic entities, form populations of which we
can determine only the arithmetic mean and the statistics of variation.
Averages are mere abstractions,- only the individuals of which populations
are composed have reality, (ibid.)
Mayr argues that the two positions express fundamentally differ-
ent philosophical stances:
The ultimate conclusions of the population thinker and the typologist are
precisely the opposite. For the typologist, the type [eidos] is real and the
variation an illusion, while for the populationist the type (average) is an
abstraction and only the variation is real. No two ways of looking at nature
could be more different, (ibid.)
It is important to say a little in defence of 'typological thinking',
lest we make the position appear absurd. As Mayr says, there are
'gaps in nature'. Organic forms that we might think possible are
never observed - there are no six-legged elephants. Moreover, some
organic structures are encountered with great regularity. Many indi-
vidual organisms, and even organisms of different species, appear
to be variations on a common underlying theme. The 'vertebrate
archetype' of Richard Owen, for example, was an effort to represent
the common structural plan, modified to various degrees in particu-
lar species, that underlies all vertebrates. We can think of 'types' as
explanatory posits: some forms are seen rarely or not at all because
there is no corresponding type; others are seen frequently because
they are variations on an underlying type. Note that for these rea-
sons Mayr's claim that for the typologist variation is 'an illusion' is
rather misleading (Sober 1980). A typologist need not claim that all
dogs are identical. But a typologist might claim that by positing a dog
type, we can explain why there are so many individual organisms
with 'doggy' characteristics.
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Mayr's equation of types with Platonic 'ideas' makes them sound
unaccountably mystical - the sorts of posits that have no business
in respectable science. It is true that some of Darwin's contempo-
raries, Owen included, made positive references to Plato. Yet the
question of how important Platonism was in the dominant strands
of typological thinking at the time the Origin was published has
been contested (Amundson 2005; see also Winsor 2006 for scepticism
regarding Mayr's historiography). The point that I wish to stress here
is that we can make 'types' more respectable by understanding them
as stable configurations of organic matter (Lewens 2007, 85-6). Mov-
ing away from biology for a moment, something like a typological
explanation seems appropriate when we try to understand why some
crystal structures are seen frequently, for example, while others are
not seen at all. We can take reference to types here to be shorthand for
sets of physical facts that make some crystalline forms stable, oth-
ers unstable. Perhaps we can think of organic types in a similar way.
The typologist claims that only a few basic organic configurations
are stable. These stable configurations then explain the diversity of
forms manifested by individual organisms.
Mayr characterises typological thinking as a sterile product of a
scientifically uninformed philosophical relic. But typologists were
pursuing a productive research program, one that the philosopher
Ronald Amundson (2005 ) convincingly argues had a positive impact
on Darwin's own work. Darwin's reading of naturalists of the typo-
logical school (people like Geoffroy St-Hilaire in France and Richard
Owen in England) pushed him to recognise the existence of an impor-
tant phenomenon in nature - the existence of underlying commonal-
ities in structure among species whose conditions of life were quite
different - that demanded explanation. So Mayr's characterisation of
typological thinking is misleading. Even so, we will see that Mayr is
right to say that Darwin is opposed to typological thinking.
Darwin says that species are formed by the action of natural selec-
tion on slight variation. His position demands, then, that these small
variations, if they can be added up to produce new species, are them-
selves stable. Hence the reason why we do not observe forms that
are intermediate between existing species cannot be that these forms
are unstable. This presents Darwin with a dilemma. On the face of
things, if he is right about common ancestry and the stability of
slight variations, there should be no gaps between existing organic
forms. On the other hand, Darwin learns from the typologists that
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The Origin and Philosophy 327
this is not the pattern we observe. So Darwin needs to give a non-
typological explanation for apparently typological phenomena:
. . . why, if species are descended from other species by insensibly fine gra-
dations, do we not everywhere see innumerable transitional forms? Why is
not all nature in confusion instead of the species being, as we see them, well
defined? [Origin, 171)
Darwin reinterprets Owen's archetypes as ancestors: the diverse ver-
tebrate species appear to be variations on a common theme not
because they are manifestations of a single timeless ground plan, but
because they have retained the characteristics of a common ancestor
[Origin, 43 5; see also Amundson 2005, Chapter 4). But Darwin's way
of thinking about shared history does not guarantee that we should
expect the world to contain species that are what he calls 'tolerably
well-defined objects' [Origin, 177). We still need some explanation
for the coherence of species, and for the gaps between them.
In response, Darwin claims that many stable forms fail to be
observed alive today because, while they may have been suited to
earlier conditions of existence, they have been driven out of popula-
tions by shifting competitive demands. He supplements this asser-
tion with geological reasoning that explains why the known fossil
record consists of a highly impoverished collection of these inter-
mediate forms [Origin, 279-311). Darwin, in other words, gives us
an alternative way of thinking about the modality of species. In this
respect, Mayr is right about the philosophical novelty of Darwin's
view. While the typologist stresses the instability of unobserved
forms given constant natural law, Darwin stresses the improbability
of the continued survival of unobserved forms given shifting com-
petitive demands. One of Darwin's primary explanatory tools for this
task is an offshoot of the more general principle of natural selection,
which Darwin calls the 'principle of divergence of character'. Darwin
had learned from Adam Smith that competition will be most intense
between individuals in the same line of business. Darwin argues that
in the economy of nature, no less than in human affairs, competi-
tive advantage will come to those who find new ways of making a
living:
. . . the more diversified the descendants from any one species become in
structure, constitution, and habits, by so much will they be better enabled
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to seize on many and widely diversified places in the polity of nature, and
so be enabled to increase in numbers. [Origin, 112)
By coupling principles such as this one to his hypothesis of common
ancestry, Darwin is able to explain the existence of discrete species
while also accounting for their underlying commonalities, and he
is able to do so in a non-typological way. This much is good news
for Mayr. What is not such good news for Mayr is that the primary
resources Darwin uses to replace typological explanation are natural
selection and the 'tree of life' hypothesis. This makes it hard to
characterise 'population thinking' as a third conceptual innovation
wholly distinct from Darwin's better-known ideas.
On Darwin's view, species are 'tolerably well-defined objects' by
virtue of the corralling forces of local environments, which disci-
pline the tendencies of individuals to vary, and thereby maintain
coherence over time at the level of the population. This population-
level coherence is achieved in spite of differences constantly being
introduced among individuals, not because of something shared by
all individuals. Philosophers and scientists have frequently latched
onto the significance of this sort of 'population thinking' and claimed
diverse consequences for topics such as race, systematics, progress,
health, and even cultural evolution. There is no sense trying to eval-
uate all of these claims here, but it is worth pointing out that when
Darwin himself wrote on many of these topics, he found ways to
reconcile his own population thinking with claims that will sound
distinctly typological to many.
The variability of species in every respect is something that
Darwin learned from his work on barnacles, and he constantly draws
our attention to it: 'I am convinced that the most experienced natu-
ralist would be surprised at the number of cases of variability, even
in important parts of structure . . . ' [Origin, 45 ). In spite of this, some
of Darwin's observational practices show scant regard for the ubiq-
uity of variation. Consider Darwin's work on domesticated pigeons.
This work seeks to show the power of artificial selection in modi-
fying domesticated species, and in doing so it points to the poten-
tial for natural selection to modify wild species. Darwin illustrates
artificial selection's power by demonstrating the degree to which
distinct domesticated varieties of pigeon differ from each other, and
the degree to which these varieties differ from wild rock pigeons. In
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The Origin and Philosophy 329
order to do this, Darwin needed to make measurements of various
traits in these different varieties. However, as James Secord points
out:
As Darwin confessed in the Variation under Domestication, his measure-
ments on the wild rock pigeon were based on only two birds, and originally
he planned to have but one. Without knowing the variation of his stan-
dard, readers must have been highly suspicious of his comparisons with
other birds. One can hardly call Darwin's work in this instance 'population
thinking', although he certainly was aware of a problem. (Secord 1981, 179)
Darwin's views on race are also noteworthy. His 'population think-
ing' made him sceptical of any exceptionless generalisation regard-
ing the members of particular human races. Even so, he was happy
to endorse fairly strong rules of thumb, including generalisations
relating to racial psychology:
Their mental characteristics are likewise very distinct. . . . Every one who
has had the opportunity of comparison, must have been struck with the
contrast between the taciturn, even morose, aborigines of S. America and
the light-hearted, talkative negroes. [Descent, 216)
And while it is true that Darwin rejected some conceptions of evo-
lutionary progress, distancing himself in the Origin's third edition
from Lamarck's belief in 'an innate and inevitable tendency towards
perfection in all organic beings' (Variorum, 223: 382.14-16:0), this
does not mean that he eschewed talk of progress altogether. Even in
the domain of race, Darwin appeared to think some form of progress,
while not inevitable, was highly likely. He offers an evolutionary
explanation for why the current gap in advancement between man
and his nearest living relative will in time become even greater:
At some future period, not very distant as measured by centuries, the
civilised races of man will almost certainly exterminate and replace through-
out the world the savage races. At the same time the anthropomorphous
apes, as Professor Schaaffhausen has remarked, will no doubt be extermi-
nated. The break will then be rendered wider, for it will intervene between
man in a more civilised state, as we may hope, even than the Caucasian,
and some ape as low as a baboon, instead of as at present between the negro
or Australian and the gorilla. [Descent, 201)
One of the reasons for Darwin's continued adherence to many
typological pronouncements in spite of his population thinking is
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3 30 TIM LEWENS
that the shift to an explanation of species composition in terms of
external ecological forces, rather than internal organismic tenden-
cies, leaves open the issue of how homogeneous we should expect
species to be. Modern evolutionary game theory has shown how
selection can actively promote the existence of mixed populations.
But this view is not entailed by the more basic Darwinian thought
that species coherence is a function of natural selection acting to
shape the variation that is constantly arising in populations.
VI. DARWIN AND PHILOSOPHY
Let us return to Mayr's assessment of the Origin in his 1964 intro-
duction to that work. He casts Darwin's conceptual innovation not
merely as a rejection of a dominant philosophy, but as a rejection
triumphantly effected without engagement with the great philoso-
phers, hence a rejection that also demonstrates the general lack
of effectiveness of traditional philosophical methods in answering
broad philosophical questions:
No one resented Darwin's independence of thought more than the philoso-
phers. How could anyone dare to change our concept of the universe and
man's position in it without arguing for or against Plato, for or against
Descartes, for or against Kant? Darwin had violated all the rules of the game
by placing his argument entirely outside the traditional framework of classi-
cal philosophical concepts and terminologies. . . . No other work advertised
to the world the emancipation of science from philosophy as blatantly as did
Darwin's Origin. For this he has not been forgiven to this day by some tra-
ditional schools of philosophy. To them, Darwin is still incomprehensible,
'unphilosophical,' and a bete noire. (Mayr 1964, xi-xii)
There are problems for Mayr's interpretation of Darwin's rela-
tionship with philosophy. Herschel was famously unimpressed by
the Origin, apparently describing the theory defended therein as
the 'law of higgledy piggledy' (quoted in Browne 2003, 107). This
remark supports Mayr's view: one might say that Herschel's failure
to appreciate Darwin's theory betrays him as one of those philo-
sophical reactionaries whose views Darwin made obsolete. But we
need to remember that Darwin modelled the Origin's argument on
Herschel's principles. If Herschel's methodological work counts as
philosophical in nature, then while it remains reasonable to regard
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The Origin and Philosophy 331
Darwin's views as being in tension with some important elements
of Victorian philosophy, one cannot claim that Darwin 'had violated
all the rules of the game.'
In other ways, Mayr is right. Darwin, as we have seen, was scepti-
cal of the ability of abstract thought alone - the 'deductive method'
of Herbert Spencer - to deliver factual conclusions regarding the
natural world. Because of this, Darwin looked to scientific obser-
vation to shed light on matters that some philosophers might still
be tempted to regard as the preserve of reason alone. But Darwin's
views put him in an established philosophical tradition - Mayr exag-
gerates Darwin's claim to be regarded as a philosophical revolution-
ary. Philosophers of the British empiricist school insisted on the
necessity of experience for the possession of knowledge, unless that
knowledge was itself restricted to abstract logical or mathemati-
cal matters. David Hume, whose works Darwin had read, famously
closed his Enquiry Concerning Human Understanding by recom-
mending that:
If we take in our hand any volume; of divinity or school metaphysics, for
instance,- let us ask, Does it contain any abstract reasoning concerning
quantity or number! No. Does it contain any experimental reasoning con-
cerning matter of fact and existence! No. Commit it then to the flames: for
it can contain nothing but sophistry and illusion. (Hume 1978, 165)
While Darwin saw considerable philosophical promise in the evo-
lutionary perspective, he was also aware that his views were in tune
with some existing themes in the history of philosophy. He wrote
in his Notebook N: 'I suspect the endless round of doubts & scepti-
cisms might be solved by considering the origin of reason, as grad-
ually developed, see Hume on Sceptical Philosophy.' [Notebooks,
348: N, 1 01 ) The Humean sceptic gives up on the possibility of find-
ing a rational justification for such things as our expectation that the
future will resemble the past, for our belief that causes in some sense
necessitate their effects, and for our inclination to regard some acts
as wrong, others as right. The Humean sceptic instead rests content
with an account of human thought and human nature that explains
why we regard these expectations and inclinations as compelling.
In this way, Hume aims to give 'sceptical solutions' to the sceptical
problems he raises. They are sceptical solutions because they con-
cede to the sceptic the impossibility of justifying our fundamental
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3 32 TIM LEWENS
practices of moral judgement, reasoning about the future, and so
forth. It would be a stretch to call Darwin a Humean sceptic, not
because Darwin is at odds with Hume, but because Darwin does not
say enough about his general philosophical stance for their views to
be closely aligned. Yet Darwin holds in common with Hume a will-
ingness to settle for description and explanation of the characteristic
habits of human thought, in lieu of watertight justifications of those
habits.
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MICHELE KOHLER AND CHRIS KOHLER
1 8 The Origin of Species as a Book
Varieties and variation were the keys to Darwin's theory of evolution
by means of natural selection - barnacles and pigeons - and varieties
and variations are the keys to our understanding of the Origin of
Species as a book.
The three largest collections of editions of the Origin are the
Kohler Collection held by the Natural History Museum in London; a
collection assembled by R. B. Freeman at the Thomas Fisher Library
of the University of Toronto; and the books collected by Warren
Mohr, Jr., now in the Henry E. Huntington Library in San Marino.
Anyone wanting to study the Origin as a book needs to have close
by a copy of R. B. Freeman's The Works of Charles Darwin: An
Annotated Bibliographical Handlist in its second edition. With all
its faults and quirks, it is indispensable.
OnNovember24, 1859, On the Origin of Species by Means of Nat-
ural Selection, or the Preservation of Favoured Races in the Struggle
for Life was published by John Murray on heavy cream-coloured
stock from Spalding, printed by W. Clowes and Sons and bound by
Edmonds & Remnant, London, in green cloth with gilt blocking
on the spine. John Murray had held a trade sale on November 22
when orders were taken for copies from booksellers, wholesalers,
and circulating libraries. Twelve hundred and fifty copies had been
printed and bound. Of those, 5 were sent to Stationers' Hall; 12 were
"allowed Author"; and 41 were "Presented Reviews" leaving 1,192
for sale (National Library of Scotland (NLS) Ace 12604/570/158).
This number was oversubscribed by 250 [Correspondence, 7: 394).
Darwin required ninety copies to be sent as presentations to friends,
family, and scientists [Correspondence, 8: 554-6). It is not clear if
that number included the 12 author's copies, but it would seem
333
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3 34 MICHELE KOHLER AND CHRIS KOHLER
that about 1,100 copies were available for sale to distributors on the
day of the trade sale. Of those, apparently 500 copies were taken
by Mudie's Subscription Library - the largest commercial lending
library in the country, which also supplied book societies and vil-
lage libraries [Correspondence, 7: 395 n.i), which means that only
600 copies were available for sale to the general public on Novem-
ber 24. Darwin has been blamed for the canard that the book sold
out completely on the first day of sale, although he actually wrote
to Lyell, "I heard, also, from Murray that he sold whole Edition the
first day to the trade" [Correspondence, 7: 394). It is quite likely that
the entire edition was sold out at bookshops soon after the twenty-
fourth.
Murray proposed a new edition immediately, and for Darwin this
was an opportunity to make emendations. Morse Peckham, in his
variorum edition, traced these and other corrections that Darwin
made to Murray editions over the next seventeen years. The Ori-
gin went through six editions during Darwin's lifetime, and for each
one he made alterations and corrections. Peckham and Freeman note
that a few further small corrections were made to the 1 876 printing,
and it is this version that was reprinted again and again by Murray.
The sixth edition differed from the first in many ways - Darwin had
been bombarded by criticisms and had made alterations as a result.
Freeman and Peckham both believed and found it highly significant
that the second through fifth editions of the Origin were printed
from type that was left standing after the printing of the first edi-
tion. They both cited this as the reason for what they mistakenly
presumed was a reduction in price of the second edition to four-
teen shillings. Freeman also thought that the "Fifth thousand" was
not really a second edition because it was made from standing type.
Recent research by Peter L. Shillingsburg has shown that, except for
the inner form of gathering X and all of gathering Y of the 1 869 edi-
tion, each new edition was completely reset (Shillingsburg 2006). For
such a well-studied title, this is a surprising and slightly disorient-
ing discovery. For example, some errors arising in the text that were
previously attributed to Darwin are probably not his at all. This new
research has implications for our whole understanding of the early
publication of the book.
In November 1901, the first edition came out of copyright in
Britain and was reprinted widely. Murray printed the following note
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The Origin of Species as a Book 335
in the 1902 "Popular Impression (copies 40,000 through 47,000) of
the corrected copyright edition issued with the author's executors"
that
Darwin's "Origin of Species" has now passed out of Copyright. It should,
however, be clearly understood that the edition which thus loses its legal
protection is the imperfect edition which the author subsequently revised,
and which was accordingly superseded. The complete and authorized edition
of the work will not lose copyright for some years.
The only complete editions authorized by Mr. Darwin and his represen-
tatives are those published by Mr. Murray.
Today another opinion is widely held - that to approach more nearly
Darwin's original and revolutionary ideas it is best not to read the
sixth edition but rather the first or its corrected version, usually
referred to as the second but actually called the "fifth thousand" on
the title page.
Freeman assigns numbers to fifty-eight editions - not all of which
he handled - although some of the listings include variant bindings.
The Natural History Museum has sixty-five in its collections; the
Huntington Library and Toronto can account for a further seven not
in the museum's collection. These are divided among three series:
the standard edition published in dark green cloth, the library edition
in two volumes, and the popular cheap edition usually bound in light
green cloth or in paper wrappers.
Murray had a deep commitment to the book - he accepted it sight
unseen based on Darwin's reputation and his own experience as
the publisher of Darwin's Journal of Researches [Correspondence, 7:
275). He had a good working relationship with his author, who was
grateful for the publisher's attentions, agreeableness, and prompt
payment of royalties. After Darwin's death, his sons, as his execu-
tors, tried Murray's patience. Murray set out his own position in a
letter of May 18, 1882, to William M. Hacon, the Darwin family
solicitor.
The very peremptory order which Mr. Darwin's executors have sent me
through you, not to reprint their Father's works without their express sanc-
tion, was scarcely required since it is my unvarying rule, observed with
all my Authors, except in cases of emergency, to apprize them when new
Editions are called for.
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3 36 MICHELE KOHLER AND CHRIS KOHLER
It has been followed in the case of Mr. Darwin ever since I became his
publisher. I need scarcely add that the orders of the Executors shall be strictly
carried out in future." (NLS Ace 12604/735/135)
The executors accepted, and the relationship continued.
The Murray Archive has recently been deposited at the National
Library of Scotland in Edinburgh. Although no new specific infor-
mation about the 1859 edition has come to light, there are lists for
the trade sales of the fifth edition on June 23, 1869 (NLS Ace 12604
Sales Book 1 869/1 870) and the sixth edition on February 14, 1872
(NLS Ace 12604 Sales Book 1871/1872).
The other major nineteenth- century English-language publisher
of the Origin was the firm of D. Appleton &. Co. in New York. Asa
Gray, the Harvard botanist and Darwin's long-time correspondent,
had offered to arrange an American edition. Although his first choice
was Ticknor and Fields in Boston, Appleton was already preparing
its text from the 1859 edition and had made stereo plates. By the
time Gray approached Appleton the second edition was on sale in
Britain, and Darwin hoped they would reprint this. Corrections and
additions were sent by ship. By May i860 Appleton had sold most
of the original 2,250 copies from three separate printings of its first
edition [Correspondence, 8: 571-2) and proceeded to produce a fourth
printing incorporating the corrections. Appleton was not obliged to
do so, but the company agreed to pay Darwin a royalty.
In 1872, Murray sent Appleton a set of stereo plates for the
sixth English edition of the Origin (NLS Ace 12604/5 66/1 18). Apple-
ton reprinted from it, which meant that the few changes made by
Darwin in 1876 - including, for example, changing "Cape de Verde"
in the text to "Cape Verde" - were not made to the Appleton one-
volume edition. Murray later supplied Appleton with stereo plates
for the two-volume edition. Gerard Wolfe claims that "the house
reprinted Darwin's classic 38 times," although he also claims that
the first Appleton edition appeared in 1859 (Wolfe 1981, 42, 112).
Freeman lists forty-seven different printings, bind-ups, and editions,
ending with the Appleton edition in two volumes in 1937. The Nat-
ural History Museum holds twenty-eight, the last of which is dated
1927. Toronto and the Huntington Library between them hold a fur-
ther twenty-two not housed in the museum, making a total of at
least fifty-editions, printings, and bindings. Murray used bindings
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The Origin of Species as a Book 337
that can be generally described as green; Appleton bound volumes
with less consistency. Although the main binding colour for Apple-
ton editions was brick red, the Natural History Museum copies are
bound in eleven different colours and cloths, including publisher's
half -maroon morocco with marbled boards. Appleton published the
Origin in one-volume, two-volume, and two-volumes-in-one for-
mats, including an Authorized Edition that they intended to be part
of a "collected edition" - owing to the Authorized Edition's being
reprinted, when actually "collected" together the resulting assem-
blages tended to vary one from the other - and a luxury Westminster
Edition.
While Murray and Appleton were dominant in the English-
language market in the nineteenth century, there were other players.
Murray sold Routledge 274 sets of sheets in 1894 (NLS Ace 12604/
658/75) and 4,004 sets of sheets in 1898 (NLS Ace 12604/570/105), at
least in part for their Sir John Lubbock Hundred Books series. There
was more competition in the American market, with a Humboldt
Library of Popular Science edition in wrappers and one from John B.
Alden in 1886 that included The Descent of Man.
The United States Congress passed a copyright law in 1891 that
included an exemption for any book first published before July 1 89 1 .
This legal clarification coincides with a rash of new American edi-
tions of the Origin. Excluding Appleton editions, for the period cov-
ering the next nine years the Natural History Museum holds twenty-
six different editions and variants published by fourteen different
American publishers in New York, Chicago, and Akron, Ohio. These
versions appeared in one or two volumes, mostly from the sixth edi-
tion, although the Hennebery Company of Chicago included prelim-
inary material with its version of the sixth edition - material last
seen in the fifth thousand of i860.
The twentieth century saw many changes and experiments in the
publication of the Origin. In England, cheap editions joined Mur-
ray's popular edition early in the century: Ward, Lock &. Co., Grant
Richards, the Unit Library, Hutchinson, Oxford World Classics,
Watts and Co. issuing for the Rationalist Press Association, Cassell
and Company, Collins Clear Type, and Dent Everyman. In Amer-
ica, early twentieth-century editions were published by P. F. Collier,
Hurst, A. L. Burt, Thomas Y. Crowell, J. A. Hill, and Rand McNally.
A leading player from the 1930s onward was the Modern Library.
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338 MICHELE KOHLER AND CHRIS KOHLER
Although Freeman cites only three issues - including a British
one - of which he himself had two, twenty-two different variants
can be found in the Natural History Museum. The Origin was reis-
sued in various colours and with the different styles of the Modern
Library torchbearer on the bindings. Using the lists of publications
on the dust wrappers and the known dates for the different torch-
bearers, it is possible to date the different issues throughout the
century.
The second half of the twentieth century was a rich time for cheap
editions in both Britain and America. Paperback editions include
those published by Penguin, Everyman, Oxford World Classics,
Mentor, Doubleday, Bantam, and Harvard University Press, using
variously the first, second, and sixth editions. The first microform
edition was part of the Readex Microprint Landmarks of Science II,
published on six cards from the fifth thousand of i860 in the 1960s.
Electronic online editions started to appear from Gutenberg and Elec-
tronic Scholarly Publishing in the 1990s. In 1997, Lightbinder Inc.
in San Francisco issued a reprint of the sixth edition on computer
optical disk, probably a CD-ROM. A version on audio cassette was
produced by Audio Scholar of Mendocino, California, in 1990. In
199 1, the shortest edition of the book was published: a children's
illustrated board book, reduced to ninety-one words with illustra-
tions enabling children "to learn from imaginative adult readers how
Darwin understood the evolving world" (Karlinsky 1991).
Throughout the twentieth century publishers vied with each
other for the imprimatur and introductory material of leading schol-
ars, scientists, and pundits: Grant Allen, Sir Arthur Keith, Leonard
Darwin, Edmund B. Wilson, C. D. Darlington, Julian Huxley, Sir
Gavin de Beer, Charles G. Darwin, Ernst Mayr, J. W. Burrow,
L. Harrison Matthews, George Gay lord Simpson, Patricia Horan,
Richard Leakey, Jeff Wallace, Dame Gillian Beer, and, most surpris-
ing of all, the anti-Darwinian W. R. Thompson, an entomologist
and director of the Commonwealth Institute of Biological Control,
Ottawa, Canada, who wrote the introduction to the 1956 Dent Every-
man edition. This was reprinted in 1967 by the Evolution Protest
Movement as New Challenging "Introduction" to The Origin of
Species Everyman Library No. 811 (1956). An edition aimed at a
more popular audience included material by Walter Cronkite and
James Michener.
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The Origin of Species as a Book 339
In Britain in the nineteenth century there were neither condensed
nor illustrated editions - a sign of continued family interest in and
control of the publication of the Origin. At the turn of the century,
Francis Darwin wrote to Murray of his brother William's disapproval
of "an illustrated Origin as very difficult to do well - even if so done
of no real use," while also conveying his own thoughts: "I don't
see that one can do better than produce a really cheap well printed
Origin - it is much better than an annotated or illustrated edition,
and it would be difficult to get these done in my opinion" (NLS
Ace 12604 Folder 109). As for condensed versions, he noted: "My
own impression is that the modern student is fed on lecture notes &.
selections until he is forgetting how to read a stiff book altogether.
And I should be sorry to let the Origin help this process - I dare-
say the book would sell, but that is not the only question" (NLS
Ace 12604 Folder 108). When the texts finally came out of copy-
right, things changed. There have been a few deluxe editions. The
Heritage Press of New York and Norwalk and the Griffin Press of
Adelaide published finely bound editions with wood engravings by
Paul Landacre. Less beautiful but probably more frequently read are
the various condensed versions - most notably What Mr. Darwin
Really Said, published by George Routledge in 1929 with an intro-
duction by Julian Huxley. Fleetway House published extracts with
a precis by C. W. Saleeby in 1926, and Quarter Books in Pasadena
published its own condensed version in 1936. Regenery of Chicago,
better known today for its anti-Darwinian material, published a vol-
ume of extracts in the 1940s. Charlotte and William Irvine abridged
the Origin for Frederick Ungar, and Richard Leakey's Illustrated
Origin of Species is also abridged - and translated into many lan-
guages. In 1996, Orion Books published Chapter 3 and the first part
of Chapter 4 of the Origin in fifty-nine pages for sixty pence. Extracts
from the Origin appear widely in collections of selections for biology
students and general readers and also occasionally in translation.
Darwin is certainly the most translated scientific author of all
time and probably one of the most translated of any author orig-
inally published in English. Before the publication of the Origin,
Darwin wrote to Murray: "I am extremely anxious for the subject
sake (& God knows not for mere fame) to have my Book translated;
& indirectly its being known abroad will do good to English Sale ..."
[Correspondence, 7: 376).
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340 MICHELE KOHLER AND CHRIS KOHLER
The German edition was first translated by Heinrich Bronn in
i860. Darwin had written to Bronn in February asking if he could
offer suggestions for a translator and if he could, perhaps, proofread
the result before publication, "for I am most anxious that the great
&. intellectual German people should know something about my
work" [Correspondence, 8: 70). Bronn did not agree with Darwin
about natural selection but produced a prompt translation himself,
with its own quirks and oddities, published by E. Schweizerbart in
Stuttgart. Darwin's greatest concern was obviously the translation
of the term "Natural Selection":
Several scientific men have thought the term "natural Selection" good,
because its meaning is not obvious, &. each man could not put on it his
own interpretation, &. because it at once connects variation under domes-
tication & nature. - Is there any analogous term used by German Breeders
of animals? - "Adelung" - ennobling - would perhaps be too metaphorical.
It is folly in me, but I cannot help doubting, whether "Wahl der Lebens-
weise" expresses my notion. - It leaves the impression on my mind of the
Lamarckian doctrine (which I reject) of habits of life being all-important.
Man has altered & thus improved the English Race-Horse by selecting suc-
cessive fleeter individuals,- &. I believe, owing to the struggle for existence,
that similar slight variations in a wild Horse, if advantageous to it, would
be selected or preserved by nature: Hence natural Selection. But I apologise
for troubling you with these remarks on the importance of choosing good
German terms for "natural Selection." [Correspondence, 8: 82-3)
Bronn finally settled on "naturliche Ziichtung" ("natural breeding")
for his translation, although it was still not exactly what Darwin
thought correct. Contrary to Freeman's note, Bronn remained the
sole translator of the second German edition, completing the revi-
sions just before his own sudden death. The third edition of 1867,
with the change from Ziichtung to Zuchtwahl or selection, was a
revision of Bronn's translation by Julius Victor Carus incorporating
Darwin's changes to the fourth Murray edition. The 1872 edition was
Carus's new German translation based on the sixth Murray edition.
The last edition to have Bronn's name on the title page is the one
dated 1876. There have been a total of eight translators of the Origin
into German: Heinrich Bronn, Julius Victor Carus, Georg Gartner,
David Hack, Paul Seliger, Dr. Richard Bohme, Dr. Heinrich Schmidt
of Jena, and Carl W. Neumann. Further editorial matter is attached to
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The Origin of Species as a Book 341
several Reclam editions by Georg Suchmann, Gerhard Heberer, Rolf
Lothar, and Gerhard H. Miiller, while Walter Domann has edited a
translation for Diesterweg.
The first Dutch translation, by Tiberius Cornelius Winkler, was
published in 1 860 - Darwin knew nothing about it until he received
a copy in 1861 [Correspondence, 9: 195). Freeman calls him T E.
Winkler in his handlist and claims that the first edition was not
published until 1864 (Freeman 1978, 221). Other Dutch translators
have included J. Klerkx in 1983, Ludo Hellemans in 2000, and Ruud
Rook in 2001. In 1958, A. Schierbeek edited a condensed version of
the Winkler translation in Darwin's werk en personlijkheid - which
was mistakenly described by Freeman as a Flemish translation.
Freeman had mistranscribed the imprint of the Wereld-Bibliotheek
edition as published in the Belgian city of Antwerp, a subsidiary
place of publication for this Amsterdam firm. In fact, there is no
Flemish language - the formal language spoken and written by the
Flemish community of Belgium is Dutch.
Even before the Origin was published Darwin had an offer from
Louise Swanton Belloc - an Irish-born French writer - to translate
his work, but she ultimately decided it was too scientific for her.
She was a friend of Darwin's friend Mary Butler [Correspondence,
7: 376-7). Pierre Theodore Alfred Talandier, a professor of French
at Sandhurst, also offered to translate the book but failed to find
a publisher [Correspondence, 8: 135). Eventually, the first French
translation was prepared by Clemence Royer, a French naturalist
living in Lausanne, Switzerland, and published in 1862. It was char-
acterised by a long preface and an abundance of explanatory texts.
Darwin described her as probably "one of the cleverest &. oddest
women in Europe," though lacking in experience as a naturalist.
Darwin tried but failed to get her to remove or modify her com-
mentary [Correspondence, 10: xx). Her translation went through at
least five editions, including a two-volume reprint of 1918. In 1873,
a translation by J. J. Moulinie appeared, "Traduit sur l'invitation et
avec l'autorisation de l'auteur sur les cinquieme et sixieme editions
anglaises ..." This was followed in 1 876 by Edmond Barbier's trans-
lation of the sixth or "l'edition Anglaise definitive," which remains,
modified by Daniel Becquemont, the standard French translation.
In September 1 874, Milan Radovanovitch wrote to Darwin asking
for his authorisation to publish a Serbian translation of the Origin
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34^ MICHELE KOHLER AND CHRIS KOHLER
[Calendar, 414). It was ready for the press in 1876 but was not pub-
lished until 1878 owing to war between the Serbs and the Turks.
The Origin was translated into a further seven languages dur-
ing Darwin's lifetime: Russian (1864), Italian (1864), Swedish (1869),
Danish (1872), Polish (1873), Hungarian (1873-74), and Spanish
( 1 877). These translations were all either initiated by their authors or
arranged by Darwin himself. It has since appeared in a further thirty-
three languages: Arabic, Armenian, Bahasa Indonesian, Basque,
Bulgarian, Catalan, Chinese, Croatian, Czech, Finnish, Gallegan,
Greek, Hebrew, Hindi, Icelandic, Japanese, Korean, Latvian, Lithua-
nian, Malayalam, Macedonian, Marathi, Norwegian, Persian, Por-
tuguese, Punjabi, Romanian, Slovakian, Slovenian, Tibetan, Turkish,
Ukrainian, and Vietnamese.
As we approach the sesquicentenary of the publication of the
Origin, what can we say about the book today? It remains in
print in English from Bantam Books, Barnes & Noble, Broadview
Press, Castle Books, Collector's Library, Dover, Everyman's Library,
Harvard University Press, Modern Library, New York University
Press, W. W. Norton, Oxford University Press, Penguin, Pickering
and Chatto, Prometheus, Running Press, Signet, and Wordsworth.
Print-on-demand editions are available from Bibliobazaar, Cosimo,
Echo Library, Elibron Classics, IndyPublish.com, Kessinger, Univer-
sity of Pennsylvania Press, ReadHowYouWant.com, Standard Pub-
lications, and Wildside Press. Editions with new introductions by
leading Darwinians, including Richard Dawkins, James Watson, and
E. O. Wilson, have recently appeared. Due to be published in 2009
are an edition for Cambridge University Press edited by Jim Ender-
sby, a new edition for Penguin edited by William Bynum, and a new
edition for John Murray edited by Olivia Judson. It remains avail-
able in translation in Chinese, Danish, Dutch, French, Gallegan,
German, Hebrew, Hungarian, Icelandic, Bahassa Indonesian, Italian,
Japanese, Korean, Norwegian, Polish, Portuguese, Punjabi, Russian,
Slovakian, Spanish, Swedish, Tibetan, and Vietnamese, and proba-
bly in several other languages that we have not been able to verify
definitively.
There is a clear distinction between the "traditional" publish-
ers and the print-on-demand publishers. The majority of the tradi-
tional publishers reprint the first edition 1859 text, and most of these
explain why they do so. Oxford World's Classics reprints the second
Cambridge Collections Online © Cambridge University Press, 2009
The Origin of Species as a Book 343
edition for reasons given by Dame Gillian Beer in her note on the
text (Beer 1996, xxix), and the Pickering & Chatto/New York Uni-
versity Press edition reprints both the first and the sixth editions
for completeness. The remaining few either use the sixth edition
with no explanation or do not cite which edition they are reprinting.
These "traditional" publishers usually provide introductory mate-
rial of varying quality. The print-on-demand publishers tend to use
whatever digital version they find on the Web without further edi-
torial comment. The exception is the University of Pennsylvania
Press, which scanned in its own 1959 variorum text and prints on
demand to satisfy distributors' orders. This is not a "photographic"
reprint as an alteration has been made to the dedicatory leaf, for
no reason that the publisher can provide. The Australian company
ReadHowYouWant.com prints on demand to order in a variety of
print formats: large print, print for those with reading disabilities
such as dyslexia, audio versions, and Braille.
The Everyman's Library edition of the Origin also includes The
Voyage of the Beagle in the same volume, while both W. W. Norton
and Running Press produce omnibus volumes printing The Voyage of
the Beagle, The Descent of Man, and The Expression of the Emotions
in Man and Animals along with the Origin.
There is a print-on-demand condensed version of the first edi-
tion published by Trafford - the editor has "taken the first edition
and removed the superfluous words" (Sheldon 2004, vii). The ver-
sion published by Broadview and edited by Joseph Carroll is the
kind of edition that Francis Darwin claimed to abhor but even he
might agree it is an interesting one. Carroll gives his account of the
volume: "The basic text for the present edition is that of the first
edition. Necessary corrections have been incorporated from the rel-
evant revisions in the second edition. Neither the trivial changes
of punctuation and phrasing nor the substantive revisions in the
second edition have been incorporated into the present text" (Car-
roll 2003, 76). The volume includes the historical sketch and the
glossary from the corrected sixth edition of 1878. Carroll also pro-
vides a full introductory essay together with a bibliographic review
of books about Darwin and evolution, adding excerpts from the four-
nal of Researches, Autobiography, Notebooks, the 1844 Manuscript,
and The Descent of Man. This is followed by excerpts from other
texts and authors: Genesis, Paley, Lamarck, Spencer, Malthus, Lyell,
Cambridge Collections Online © Cambridge University Press, 2009
344 MICHELE KOHLER AND CHRIS KOHLER
Wallace, and Huxley (Carroll 2003, 76). The Origin appears online
or can be downloaded in its first through sixth Murray editions and
in Danish, French, German, Italian, and Russian translations. There
are electronic books from xlibris.com, Ebooks.lib, Digireads.com,
Nuvision, and E-classics. There are audio CDs from Tanton and
Pisces Conservation Limited and even "free audio mp3 files . . . for
downloading onto a computer or portable mp3 player" (www.darwin-
online.org.uk/audio_darwin.html). In the audio version that he has
edited and read for CSA, Richard Dawkins's "priority was to cut
those passages that are now known to be wrong, notably those con-
cerned with genetics" (Dawkins 2006, insert). An interesting new
project for 2009 is a genetic electronic edition of the Origin in
progress at the University of Birmingham under the direction of
Barbara Bordalejo and her colleagues. It is designed to show the cre-
ative process behind the text. Like a variorum, it will show the
changes through the first six editions, but it "will also include
manuscript materials going back, at least, to 1842. We are develop-
ing a view that will allow the reader to see the text develop in front
of her eyes" (personal e-mail to the authors from Barbara Bordalejo,
June 6, 2007).
How many copies of the Origin are now sold each year? We asked
the publishers of current editions for their latest annual sales fig-
ures, promising them anonymity. Some cooperated, some did not.
Our best informed estimate is that approximately 75,000 to 100,000
copies of the Origin are now sold in many different languages
throughout the world each year.
Until this point we have been considering the publishing history
of the book. However, it is worth noting that the Origin has had a
long and interesting life in the antiquarian book trade. From 1859
readers have recognised the importance of the Origin and tended to
keep their copies, with the result that the first edition has never been
a rare book and has been regularly offered for sale at auction and by
antiquarian booksellers.
Bernard Quaritch have been antiquarian booksellers in London
since 1847 and remain one of the world's greatest firms. They sold
early editions of the Origin throughout the nineteenth century, often
at a discount to the published price, but never offered it as a first
edition aimed at the private collector. In 1862, they offered the 1861
third edition for sale at ns.8d., calling it the "last edition of this
Cambridge Collections Online © Cambridge University Press, 2009
The Origin of Species as a Book 345
remarkable book (pub. at 14s)/' and in 1865 they offered the same
edition, describing it as "one of the most important publications of
our times." An 1 881 catalogue entry says "Origin of Species . . . cloth,
5s. 1859."
The change came in 1903 when Quaritch offered an 1859 Origin,
stating that it was the first edition, presenting Darwin's theories in
their original form, and consequently would be of interest to "the
collector." The price was £2-10-0, a premium on the price of a new
copy, not a discount.
The first auction record that we have found for the first edition
is for a copy bound in calf and including a Darwin autograph letter,
which sold at Sothebys for £2 in 1905. In the years since, some
three hundred copies have appeared at auction. All prices mentioned
hereafter are for good copies of the first edition in the original cloth,
unless otherwise stated. We have, in the main, excluded copies in bad
condition and copies presented by Darwin to colleagues or friends
and copies containing autograph letters. The prices of copies sold
outside Britain have been converted to pounds sterling, at the rates
prevailing at the time of the sale.
Book auctioneers were primarily wholesalers to the antiquarian
trade until recent times, and most copies of the Origin were sold
to booksellers, mainly buying for their stock. Nowadays auctioneers
court the private collector and hope sometimes to sell important and
expensive books and manuscripts directly to collectors.
Before the First World War, three further copies sold for between
one guinea and two pounds. Although Quaritch had promoted the
first edition in 1 903, the book was not yet sought after by private col-
lections. Seymour de Ricci's influential The Book Collectors Guide,
published in 1921, does not mention Darwin.
Auction prices of the Origin started to rise in the late 1920s,
and in November 1929 the innovative booksellers Elkin Mathews
paid the highest price yet, £80, for a first edition that contained
a four-page Darwin autograph letter. A. W. Evans, senior director
of Elkin Mathews, was keen to push those books that he thought
were not sufficiently appreciated by collectors and priced the book
at £1 30, noting in the catalogue entry of December 1929: "one of the
epoch-making books of the nineteenth century, or, indeed of all time,
for Darwin's evolution theory not only revolutionised biology but
'changed the whole intellectual outlook of mankind'. . . . Darwin has
Cambridge Collections Online © Cambridge University Press, 2009
346 MICHELE KOHLER AND CHRIS KOHLER
influenced the whole range of human thought, and his book is com-
parable, on this account, with Galileo's Dialogues or Newton's Prin-
cipia" (Elkin Mathews 1929, item 15; thanks to the Lilly Library,
Indiana University, Bloomington, Indiana, for permission to quote
from their copy in the Elkin Mathews archive). In the eighty years
since, no bookseller or auctioneer has put it better. Evans's judge-
ment was right, but the timing was poor. The Wall Street crash ended
the boom years, and depression followed. Elkin Mathews finally sold
this copy for £45 in 1932. Some fifty more copies were sold at auc-
tion during the 1930s, more than in any other decade, and the average
price was down to £12 by 1939.
By the late 1950s the average auction price was £36, increasing to
£100 during the first half of the 1960s and then to £250 by the end of
that decade. Ten years later copies were going for almost £1,000, and
in 1 978 Quaritch offered a copy, "the finest we have seen," for almost
£3,000. And so it went - up. By the middle of the 1980s auction
prices were averaging almost £4,000, and between 1989 and 1990
three copies fetched over £10,000 each. By the late 1990s the price
had risen to an average of £17,500, with one copy selling for £49,000
in 1999. The record auction price for a good copy of the first edition
of the Origin in original cloth was achieved in New York in 2001,
when it fetched £101,000. Prices came down after that, with the
average price for the eleven copies sold at auction in the twenty-first
century being about half that record figure.
What were the factors driving the price up? The importance of
the book has always been acknowledged, but in recent years more
and more collectors have recognised this - partly through the publi-
cation in 1967 of Printing and the Mind of Man, which has become
the bible for collectors of important and influential books in the
development of human thought; partly as a result of the marketing
skills of the auction houses and antiquarian booksellers; and partly
through investment buying.
A generation of private collectors is now buying famous and
important science books. They want fine copies of the great books
and see the Origin as an icon, as a landmark, as a trophy. A lot of
these buyers have made their money in business, often in America
and often in businesses in the science and technology fields.
The growth of interest in this area has outstripped all other collec-
ting fields in recent years. There is a difference between the words
Cambridge Collections Online © Cambridge University Press, 2009
The Origin of Species as a Book 347
"famous" and "important." The pricing of significant science books
in the rare book market tends to favour fame over importance.
Euclid's Elements (Elementa Geometriae, 1482), Copernicus's De
Revolutionibus [De Revolutionibus Orbium Coelestium, 1543),
Newton's Principia [Philosophiae Natuialis Principia Mathematica,
1687), and Darwin's On the Origin of Species are all very famous and
very important books. Their values are: Euclid, £ioo,ooo/£225,ooo ;
Copernicus, £250,000/^500,000; Newton, £i25,ooo/£225,ooo; Dar-
win, £5 o,ooo/£i 00,000. There are other science books that are impor-
tant but that are not famous: Darwin took the first edition of Lyell's
Principles of Geology, three volumes, 1830-33, with him on the
Beagle - its value now is £3,ooo/£5,ooo.
Dick Whittington went to London to see if the streets were indeed
paved with gold. We went to London to see if we could find Dar-
win gold. We did. We visited antiquarian bookshops and saw twelve
copies of the Origin that had been published in Darwin's lifetime -
three first editions, one each of the second, third, and fifth editions,
and six of the sixth edition. We know that Quaritch bought twenty-
five copies of the sixth edition at Murray's trade sale in February
1872; currently (summer 2007) they have for sale, for £200,000, a
remarkable copy of the first edition. This is the presentation copy to
William Carpenter, one of the earliest and most influential reviewers
of the book, inscribed in ink "From the author" by one of Murray's
clerks (as usual) and with Carpenter's pencil annotations in the text.
(We are grateful to a number of antiquarian booksellers for their help
with this section, in particular to Anthony Payne for allowing us to
look at Quaritch's records and to Julian Wilson of Maggs for alerting
us to Elkin Mathews's pushing of the Origin in the late 1920s.)
The Origin of Species was originally published at a price of four-
teen shillings, but there is a long history of claiming that the price
for the first edition was fifteen shillings. On November 2, 1859, John
Murray wrote to Darwin: "Now as to price - the book from its bulk
&. size will not be dear at 14/-. 8k this is the price I propose. . . . The
only alternative is 12/-. ... At 14/- the lowest trade allowance will
be 9/6" [Correspondence, 7: 364-5). Darwin replied the next day: "I
have received your kind note 8k the copy: I am infinitely pleased 8k
proud at the appearance of my child. - 1 quite agree to all you propose
about price. . . " [Correspondence, 7: 3 65). The book was listed in Tie
English Catalogue for 1859 at I 4 S - (thanks to Professor Simon Eliot
Cambridge Collections Online © Cambridge University Press, 2009
348 MICHELE KOHLER AND CHRIS KOHLER
for this reference). Simple enough, but . . . George Paston, in At John
Murray's: Records of a Literary Circle 1843-1892, wrote that "The
Origin of Species by means of Natural Selection, or The Preservation
of Favoured Races in the Struggle for Existence - to give the book its
full title [sic] - appeared in November. Much to the astonishment
of the author, the whole edition of 1,250 copies at 15s. was sold at
Murray's annual sale. . . " (Paston 1932, 173). A copy of the relevant
letter was held at Murray's, so there is no excuse for the error. All cal-
culations for the edition in Murray's accounts are based on a price of
9s. 6d. to the trade (NLS Ace. 12604/158/158). Paston seems to have
had no understanding of the different editions published by Murray,
conflating titles and also referring to the Historical Introduction as
if it were part of the first edition when it did not appear until the
third edition of 1 86 1 . In his introductory material Peckham cites the
letter from Darwin to Murray of November 3 saying that "he was in
agreement about the price which was to be 15s" (Peckham, 16). He
repeats that "the retail price was 1 5/0" on the following page, where
he also states that Darwin got £90 when the figure in the Murray
accounts that he records is £1 80. Freeman comments about the fifth
thousand that "[t]he price fell to 14s." (Freeman 1977, 78). Desmond
and Moore, in their biography of Darwin, state that the price was fif-
teen shillings (Desmond and Moore 1991, 476). Richard Dawkins, in
the insert for his CD reading of the Origin, claims that the book was
"priced at fifteen shillings (the equivalent of 75P, but at a time when
it was possible to live on a pound a week)" (Dawkins 2006, insert).
James Secord concurs: "The Origin looked like the standard run of
books published by John Murray, with green cloth casing, fifteen
shilling price, and octavo size" (Secord 2000, 508). The book was in
Murray green cloth; the book was octavo size, though in gatherings
of twelves - which accounts for the book frequently being described
as duodecimo - but the book was not priced at fifteen shillings, nor
was that a standard price for Murray books; there are only a handful
of titles priced at fifteen shillings in Murray's own inserted advertise-
ments. Janet Browne in her Darwin's Origin of Species: A Biography
gets it right at fourteen shillings (Browne 2006, 6).
How did print runs of the Origin compare with those of other
revolutionary scientific books of its time? Evolutionary theories and
transmutation were part of the common intellectual life in 1859,
in large part as a result of the anonymous publication of Robert
Cambridge Collections Online © Cambridge University Press, 2009
The Origin of Species as a Book 349
Chambers's Vestiges of the Natural History of Creation. James Sec-
ord has studied the print runs for this title and found that the book
went through eleven editions between 1844 and i860, for a total of
23,350 copies printed (Chambers 1994, xxvii). He provides a compar-
ative chart in his Victorian Sensation (Secord 2000, 526) and shows
that by 1882, 25,500 copies of both Vestiges and the Origin had been
printed in Britain. His chart shows that in 1890 about 39,000 copies
of Vestiges had been printed and, using Peckham's data, indicates
that this equalled the Murray production of the Origin, whereas
the actual total for the Origin should be 40,750, including the more
sumptuous two-volume edition (NLS Ace. 12604, various ledgers).
In 1 92 1, when Murray last reprinted the sheets of the Origin, the
total figure for Darwin's book produced from Albemarle Street was
175,144 copies, and although 1,706 copies were washed (i.e., pulped)
sometime between 1932 and 1943, the book remained in print with
Murray through the 1940s, with the last entry in the ledger showing
three copies on hand on December 31, 1948 (John Murray Albemarle
Street Archive, Copies Ledgers Bi/Cr. 154 and Mi/296).
The other revolutionary title that makes an interesting compari-
son is Sir Charles Lyell's Principles of Geology, the first volume of
which was published by John Murray in 1830 and taken by Darwin
on HMS Beagle. It was a multivolume work - volumes two and three
were sent out to Darwin in South America on publication. The print
run reached 29,500 sets in 1875 (Baldwin 1998, 114). Lyell's book was
much more expensive than Darwin's. Surprisingly, there really is not
much difference in the figures for the three titles during Darwin's
lifetime.
There is no full-scale Darwin bibliography. In an appendix,
Peckham gives full bibliographic descriptions of some of the editions
published by Murray but does not take into account the variant bind-
ings. He would appear to have looked at single copies of many of the
editions he describes - but this is not a bibliography. R. B. Freeman
first published The Works of Charles Darwin: An Annotated Biblio-
graphical Handlist in 1965, but it is the "second edition, revised and
enlarged" of 1977 that is usually cited. Freeman called it a handlist,
not a bibliography, which has not prevented the widespread belief
that it is the Darwin bibliography. He himself notes that "[tjhere
is no full bibliographical work even of the first editions of CD's
books" (Freeman 1978, 79-80). The Freeman handlist has rightly
Cambridge Collections Online © Cambridge University Press, 2009
3 50 MICHELE KOHLER AND CHRIS KOHLER
been important in framing our understanding of the publishing his-
tory of Darwin's various titles - collectors, booksellers, librarians,
and scholars refer to Freeman.
There are several problems with the handlist. Freeman was a
scientist who collected books. He had a deep interest in Darwin,
but he was not a bibliographer. He uses the digressive method for
describing reprints, and this leads, sometimes, to a mess, especially
when he combines variants in one entry and then on other occasions
gives them separate entries. Entries refer back to previous ones that
they appear to replicate, and when this means going back a page or
more it can be maddening, especially if there is a typo or an error.
Freeman included items in his list that he had never handled; he
was dependent on descriptions produced by others and had no way
of knowing whether or not they were correct. His dating is problem-
atic. His cavalier use or nonuse of square brackets for dates causes
problems when the date on the title page is the issue point. There
are a number of typographical errors and transposed numbers, which
can be exasperating for the user.
None of this would seem to matter so much as the book is in
limited supply. However, as part of his project of mounting all of
Darwin on the Web, John van Wyhe, in an admirable effort to make
bibliographical information widely available, has put the handlist,
together with updates, on his website. Freeman's own update is
known in the book trade in the form of a badly mimeographed samiz-
dat publication handed around like a secret code but of little real use
or interest. Considerable effort has been made by van Wyhe to deal
with the problems of the digressive nature of Freeman, but his not
having seen the original volumes themselves has again led to errors
that will mislead and confuse collectors and scholars who use the
website without handling the books. For example, as already noted,
when Heinrich Bronn published his German translation of the Ori-
gin he used the expression "naturliche Ziichtung" on the title page.
By the third edition this had become "naturliche Zuchtwahl," but
in the online version it remains in its original form through the 1 882
edition, when the online version no longer lists the title in German.
As we go to press we have learned that the American Philosoph-
ical Society in Philadelphia has acquired the Darwin collection of
Professor James W. Valentine, Professor Emeritus in the Depart-
ment of Integrative Biology at the University of California, Berkeley.
Cambridge Collections Online © Cambridge University Press, 2009
The Origin of Species as a Book 351
Collecting for fifty years, Professor Valentine has accumulated nearly
one thousand different copies of the Origin, including items not in
the Natural History Museum, Toronto, or Huntington collections.
Starting with these major collections of the Origin together with the
Murray Archive at the National Library of Scotland and the Darwin
manuscript material at the Cambridge University Library, it should
be possible to compile a full-scale bibliography of Darwin's works.
The task, though, is enormous. Perhaps such a book will be available
for the bicentenary of the Origin.
Varieties and variation - it is clear that from i860 onward there
were various editions available to anyone seeking to read the Origin.
They vary in price, printing, binding, advertisements, language, for-
mat (including electronic and audio), and indeed even in the actual
text. Once the first edition came out of copyright, the introductory
material also varied. It is time now for a modern critical edition
of the Origin. Today it is possible to study some 1,000 different
copies in one place, fulfilling the Romantics scholar Charles Robin-
son's editorial requirement that "any editing that is going on must
have complete runs of books, early and late, good and bad" (personal
e-mail to the authors, June 2, 2002). The introductions in editions in
English and in translation reflect changing knowledge about and atti-
tudes toward evolution by natural selection and provide a history of
how Darwin's classic has been presented to readers throughout the
last 150 years. Such a critical edition would help to resolve many of
the issues raised by Peckham fifty years ago in his own introduction.
"Here is a task for a dozen maids with a dozen mops for more than a
dozen years. Such an edition, once completed, would be a foundation
for future studies" (Peckham, 10).
Cambridge Collections Online © Cambridge University Press, 2009
Cambridge Collections Online © Cambridge University Press, 2009
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