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Full text of "Man In The Modern World"

EUGENICS AND SOCIETY
to the bias in favour of common sense and accepted modes of thought
which equally inevitably beset the pioneers in the early stages of the
natural sciences. And just as in the natural sciences men had to
develop the technique of controlled experiment and verified prophecy
and to be willing to follow their findings wherever they might lead,
far away from the beaten track of common sense if need be, so in the
social sciences a means must be found to detect and discount bias in
the observer himself, even though this lead him far from the comfort-
able road of his preconceived notions.
Let me develop these points a little more fully, one by one. In
the first place, one and the same genetic outfit will give different
effects in different environments. This is so elementary and funda-
mental a fact that it has often been neglected, by the geneticist as well
as the eugenist. In the early literature of modern genetics, you will
often find references to the inheritance of such and such characters.
But characters are not and cannot be inherited, in the sense in which
inheritance is used by the geneticist. What are inherited are genes,
factors, genetic outfit. Any character whatsoever can only be a
resultant between genes and environment, A given character ex-
presses the interaction between a particular set of genes and a par-
ticular set of environmental conditions. Thus at the outset we see
that the old question, whether nature or nurture is the more important,
is meaningless. It is like the question "When did you stop beating
your wife?" in conveying implications which do not correspond with
reality. In general, neither nature nor nurture can be more im*
portant, because they are both essential.
You will note that I say "in general." In particular cases, one or
the other may be more important. Do not let us forget that all
genetics depends on a study of differences. We take two individuals
and strains, and ask what is the cause of the difference between them,
By adjusting the conditions of our experiment, we find that this is due
either to a difference in their environment or to a difference in their
inherited constitution (or, often, to a difference in both). We then
proceed further and find out, say, that the gcknetic difference is due
primarily to a difference in a single gene. Let us suppose that the
difference was one between red and white flowers in a plant. Then
we say, if the white-flowered variety is the aberrant one, that we have
discovered "a gene for white flower-colour." But this is a shorthand
notation. Scientifically, we have discovered that the main cause of
the difference in flower-colour is a difference in the nature of one
unit-section of the chromosome outfit. That is why certain authors
tried at one time to substitute the term differential for gene*
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