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4TUS
THE PllINCIPLES
OF
PSTCHOLOaT
BY
WILLIAM JAMES
PROFESSOR OF PSYCHOLOGY IN HARYARD UNIVERSITY
IN TWO VOLUMES
VOL. II
'^LIOTi
MAOMILLAN AND CO, Lm
PRINTED IN THE U. S. A.
CONTENTS.
CHAPTER XVII.
PAOB
Sensation, 1
Its distinction from perception, 1. Its cognitive function —
acquaintance with qualities, 3. No pure sensations after the first
days of life, 7. The ' relativity of knowledge,' 9. The law of
contrast, 13. The psychological and the physiological theories
of it, 17. Bering's experiments, 20. The ' eccentric projection '
of sensations, 31.
CHAPTER XVIII.
Imagination, . 44
Our images are usually vague, 45. Vague images not neces-
sarily general notions, 48. Individuals differ in imagination ;
Galton's researches, 50 The 'visile' type, 58. The 'audile'
type, 60. The motile' type, 61. Tactile images, 65. The neural
process of imagination, 68. Its relations to that of sensation, 73.
CHAPTER XIX.
The Perception of ' Things,' 76
Perception and sensation, 76. Perception is of definite and
probable things, 82. Illusions, 85 ;— of the first type, 86 ;— of
the second type, 95. The neural process in perception, 103.
'Apperception,' 107. Is perception an unconscious inference?
111. Hallucinations, 114. The neural process in hallucination,
123. Binet's theory, 129. ' Perception -time, ' 131.
CHAPTER XX.
The Perception of Space, 134
The feeling of crude extensity, 134. The perception of spatial
order, 145. Space-' relations,' 148. The meaning of localization,
153. 'Local signs.' 155. The construction of ' real ' space, 166.
The subdivision of the original sense-spaces, 167. The sensation
iii
IT CONTENTS.
PA»B
of motion over surfaces, 171. The measurement of the sense-
spaces by each other, 177. Their summation, 181. Feelings of
movement in joints, 189. Feelings of muscular contraction, 197.
Summary so far, 202. How the blind perceive space, 203.
Visual space, 211. Helmholtz and Reid on the test of a sensation,
216. The theory of identical points, 222. The theory of projection,
228. Ambiguity of retinal impressions, 231 ; — of eye-movements,
234 The choice of the visual reality, 237. Sensations which
we ignore, 240. Sensations which seem suppressed, 243. Dis-
cussion of Wundt's and Helmholtz 's reasons for denying that
retinal sensations are of extension, 248. Summary, 368. His-
torical remarks, 270.
CHAPTER XXL
The Perception of Reality, 283
Belief and its opposites, 283. The various orders of reality,
287. * Practical ' realities, 393. The sense of our own bodily
existence is the nucleus of all reality, 297. The paramount reality
of sensations, 299. The influence of emotion and active impulse
on belief, 307. Belief in theories, 311. Doubt, 818. Relations
of belief and will, 330.
CHAPTER XXn.
Reasoning, 323
' Recepts,' 327. In reasoning, we pick out essential qualities,
329. What is meant by a mode of conceiving, 332. What is
involved in the existence of general propositions, 337. The two
factors of reasoning, 340. Sagacity, 343. The part played by
association by similarity, 345, The intellectual contrast between
brute and man : association by similarity the fundamental human
distinction, 348. Different orders of human genius, 860 .
CHAPTER XXm.
The Production of Movement, ..... 373
The diffusive wave, 373. Every sensation produces reflex
effects on the whole organism, 874.
CHAPTER XXIV.
Instinct, 383
Its definition, 883. Instincts not always blind or invariable,
389. Two principles of non -uniformity in instincts : 1) Their
inhibition by habits, 394 ; 3) Their transitoriness, 898. Man has
CONTENTS. V
PAQK
more instincts than any other mammal, 403. Reflex impulses,
404. Imitation, 408. Emulation, 409. Pugnacity, 409. Sym-
pathy, 410. The hunting instinct, 411. Fear, 415. Acquisitive-
ness, 422. Constructiveness, 426, Play, 427. Curiosity, 429.
Sociability and shyness, 430. Secretiveness, 432. Cleanliness,
484. Shame, 435. Love, 437. Maternal love, 439.
CHAPTER XXV.
The Emotions, 442
Instinctive reaction and emotional expression shade imper-
ceptibly into each other, 442. The expression of grief, 443 ; of
fear, 446 ; of hatred, 449. Emotion is a consequence, not the
cause, of the bodily expression, 449. Difficulty of testing this
view, 454. Objections to it discussed, 456, The subtler emotions,
468. No special brain-centres for emotion, 472. Emotional dif-
ferences between individuals, 474. The genesis of the various
emotions, 477.
CHAPTER XXVI.
Will, 486
Voluntary movements : they presuppose u memory of invol-
untary movements, 487. Kinsesthetic impressions, 488. No need
to assume feelings of innervation, 503, The ' mental cue ' for a
movement may be an image of its visual or auditory effects as
well as an image of the way it feels, 518. Ideo motor action, 522.
Action after deliberation, 528. Five types of decision, 531. The
feeling of effort, 535. Unhealthiness of will : 1) The ex-
plosive type, 537 ; 2) The obstructed type, 546, Pleasure and
pain are not the only springs of action, 549. All consciousness is
impulsive, 551. What we will depends on what idea dominates
in our mind, 559. The idea's outward effects follow from the
cerebral machinery, 560. Effort of attention to a naturally
repugnant idea is the essential feature of willing, 562. The
free-will controversy, 571, Psychology, as a science, can safely
postulate determinism, even if free-will be true, 576. The edu-
cation of the Will, 579. Hypothetical brain-schemes, 582.
CHAPTER XXVII.
Hypnotism, 594-616
Modes of operating and susceptibility, 594. Theories about
the hypnotic state, 596. The symptoms of the trance, 601.
Vl CONTENTS.
CHAPTER XXVIII.
PAoa
Necessary Truths and the Effects of Experience, . 617
Programme of the chapter, 617. Elementary feelings are
innate, 618. The question refers to their combinations, 619.
What is meant by 'experience,' 620. Spencer on ancestral ex-
perience, 630. Two ways in which new cerebral structure arises :
the 'back-door ' and the ' front-door' way, 625. The genesis of
the elementary mental categories, 631. The genesis of the
natural sciences, 633. Scientific conceptions arise as accidental
variations, 636. The genesis of the pure sciences, 641. Series of
evenly increasing terms, 644. The principle of mediate compari-
son, 645. That of skipped intermediaries, 646. Classification,
646. Predication, 647. Formal logic, 648. Mathematical
propositions, 652. Arithmetic, 653. Geometry, 656. Our doc-
trine is the same as Locke's, 661. Relations of ideas v. couplings
of things, 663. The natural sciences are inward ideal schemes
with which the order of nature proves congruent, 666. Meta-
physical principles are properly only postulates, 669. -Esthetic
and moral principles are quite incongruent with the order of
nature, 672. Summary of what precedes, 675. The origin of
instincts, 678. Insufficiency of proof for the transmission to the
next generation of acquired nabits, 681, Weismann's views, 683.
Conclusion, 688.
PSYCHOLOGY.
CHAPTEE XYII.
SENSATION.
After inner perception, outer perception ! The next
three chapters will treat of the processes by which we cog-
nize at all times the present world of space and the mate-
rial things which it contains. And first, of the process
called Sensation.
SENSATION AND PEKOEPTION DISTINOUISHED.
The vxyrds Sensation and Perception do not carry very
definitely discriminated meanings in popular speech, and in
Psychology also their meanings run into each other. Both
of them name processes in which we cognize an objective
world ; both (under normal conditions) need the stimula-
tion of incoming nerves ere they can occur ; Perception
always involves Sensation as a portion of itself ; and Sensa-
tion in turn never takes place in adult life without Percep-
tion also being there. They are therefore names for dif-
ferent cognitive functions^ not for diff'erent sorts of mental
/ac^. The nearer the object cognized comes to being a
simple quality like *hot,' *cold,* *red,' * noise,' *pain,* ap-
prehended irrelatively to other things, the more the state
of mind approaches pure sensation. The fuller of relations
the object is, on the contrary ; the more it is something
classed, located, measured, compared, assigned to a func-
tion, etc., etc.; the more unreservedly do we call the state
of mind a perception, and the relatively smaller is the part
in it which sensation plays.
Sensation, then, so long as we take the analytic point of
2 P8Y0E0L00T.
view, differs from Perception only in the extreme simplicity of its
object or content.* Its function is that of mere acquaintance
with a fact. Perception's function, on the other hand, is
knowledge about f a fact ; and this knowledge admits of
numberless degrees of complication. But in both sensa-
tion and perception we perceive the fact as an immediately
present outward reality, and this makes them differ from
'thought' and * conception,' whose objects do not appear
present in this immediate physical way. From the physio-
* Some persons will say that we never have a really simple object or
content. My definition of sensation does not require the simplicity to be
absolutely, but only relatively, extreme. It is worth while in passing,
however, to warn the reader against a couple of inferences that are often
made. One is that because we gradually learn to analyze so many quali-
ties we ought to conclude that there are no really indecomposable feelings
in the mind. The other is that because the processes that produce our sen-
sations are multiple, the sensations regarded as subjective facts must also
be compound. To take an example, to a child the taste of lemonade comes
at first as a simple quality. He later learns both that many stimuli and
many nerves are involved in the exhibition of this taste to his mind, and
he also learns to perceive separately the sourness, the coolness, the sweet,
the lemon aroma, etc. , and the several degrees of strength of each and all
of these things, — the experience falling into a large number of aspects,
each of which is abstracted, classed, named, etc., and all of which appear
to be the elementary sensations into which the original * lemonade flavor '
is decomposed. It is argued from this that the latter never was ine simple
thing which it seemed. I have already criticised this sort of reasoning
in Chapter VI (see pp. 170 ff.). The mind of the child enjoying the simple
lemonade flavor and that of the same child grown up and analyzing it are
in two entirely different conditions. Subjectively considered, the two
states of mind are two altogether distinct sorts of fact. The later mental
state says ' this is the same flavor {or fluid) which that earlier state per-
ceived as simple,' but that does not make the two states themselves identical.
It is nothing but a case of learning more and more aibout the same topics
of discourse or things. — Many of these topics, however, must be confessed
to resist all analysis, the various colors for example. He who sees blue and
yellow * in ' a certain green means merely that when green is confronted
with these other colors he sees relations of similarity. He who sees abstract
' color * in it means merely that he sees a similarity between it and all the
other objects known as colors. (Similarity itself cannot ultimately be ac-
counted for by an identical abstract element buried in all the similars, as
has been already shown, p. 492 ff.) He who sees abstract paleness, inten-
sity, purity, in the green means other similarities still. These are all out-
ward determinations of that special green, knowledges «&(m< it, zufdlligeAn-
sichten, as Herbart would say, not elements of its composition. Compare
the article by Meinong in the Vierteljahrschrif t f ilr wiss. Phil. , xn. 384.
f See above, p. 221.
8EN8ATI0K 8
logtccd point of view both sensations and perceptions differ from
* thoughts ' (in the narrower sense of the word) in th^fad that
nerve-currents coming in from the periphery are involved in their
production. In perception these nerve-currents arouse volumi-
nous associative or reproductive processes in the cortex; but when
sensation occurs alone, or with a minimum of perception, the ac-
companying reproductive processes are at a minimum too.
I shall in this chapter discuss some general questions
more especially relative to Sensation. In a later chapter
perception will take its turn» I shall entirely pass by the
classification and natural history of our special 'sensa-
tions/ such matters finding their proper place, and being
sufficiently well treated, in all the physiological books.*
THE COGNITIVE FUNCTION OP SENSATION.
A pmre sensation is an abstraction; and when we adults
talk of our * sensations ' we mean one of two things : either
certain objects, namely simple qualities or attributes like
hard, hot, pain; or else those of our thoughts in which
acquaintance with these objects is least combined with
knowledge about the relations of them to other things. As
we can only think or talk about the relations of objects
with which we have acquaintance already, we are forced to
postulate a function in our thought whereby we first become
aware of the bare immediate natures by which our several
objects are distinguished. This function is sensation.
And just as logicians always point out the distinction
between substantive terms of discourse and relations found
to obtain between them, so psychologists, as a rule, are
ready to admit this function, of the vision of the terms or
matters meant, as something distinct from the knowledge
about them and of their relations inter se. Thought with
the former function is sensational, with the latter, intellec-
tual. Our earliest thoughts are almost exclusively sensa-
tionaL They merely give us a set of thats, or its, of subjects
* Those who wish a fuller treatment than Martin's Human Body affords
may be recommended to Bernstein's * Five Senses of Man,' in the Interna
tional Scientific Series, or to Ladd's or Wundt's Physiological Psychology.
The completeit compendiimi is L. Hermann's Handbuch der Physiologie,
¥0l. m
4 PBTOHOLOQT.
of discourse, with their relations not brought out. The first
time we see lights in Condillac's phrase we are it rather
rather than see it. But all our later optical knowledge is
about what this experience gives. And though we were
struck blind from that first moment, our scholarship in the
subject would lack no essential feature so long as our mem-
ory remained. In training-institutions for the blind they
teach the pupils as much about light as in ordinary schools
Keflection, refraction, the spectrum, the ether-theory, etc.,
are all studied. But the best taught born-blind pupil of
such an establishment yet lacks a knowledge which the
least instructed seeing baby has. They can never show him
what light is in its * first intention ' ; and the loss of that
sensible knowledge no book-learning can replace. All this
is so obvious that we usually find sensation * postulated *
as an element of experience, even by those philosophers who
are least inclined to make much of its importance, or to
pay respect to the knowledge which it brings.*
* " The sensations which vre postulate as the signs or occasions of our
perceptions" (A. Seth: Scottish Philosophy, p. 89). "Their existence is
supposed only because, without them, it would be impossible to account
for the complex phenomena which are directly present in consciousness "
(J. Dewey: Psychology, p. 34). Even as great an enemy of Sensation as
T. H. Green has to allow it a sort of hypothetical existence under protest.
" Perception presupposes feeling " (Contemp. Review, vol. xxxi. p. 747),
Cf . also such passages as those in his Prolegomena to Ethics, §§ 48, 49.^
Physiologically, the sensory and the reproductive or associative processes
may wax and wane independently of each other. Where the part directly
due to stimulation of the sense-organ preponderates, the thought has a
sensational character, and differs from other thoughts in the sensational
direction. Those thoughts which lie farthest in that direction we call sen-
sations, for practical convenience, just as we call conceptions those which
lie nearer the opposite extreme. But we no more have conceptions pure
than we have pure sensations. Our most rarefied intellectual states involve
some bodily sensibility, just as our dullest feelings have some intellectual
scope. Common-sense and common psychology express this by saying
that the mental state is composed of distinct fractional pa/rts, one of which
is sensation, the other conception. We, however, who believe every
mental state to be an integral thing (p. 276) cannot talk thus, but must
speak of the degree of sensational or intellectual character, or function, ol
the mental state. Professor Hering puts, as usual, his finger better upon
the truth than any one else. Writing of visual perception, he says: "It
is inadmissible in the present state of our knowledge to assert that first
and last the same retinal picture arouses exactly the same pure seniatioUf
SENSATION. 6
But the trouble is that most, if not all, of those who
admit it, admit it as a fractional part of the thought, in the
old-fashioned atomistic sense which we have so often criti-
cised.
Take the pain called toothache for example. Again
and again we feel it and greet it as the same real item in
the universe. We must therefore, it is supposed, have a
distinct pocket for it in our mind into which it and nothing
else will fit. This pocket, when filled, is the sensation of
toothache ; and must be either filled or half-filled whenever
and under whatever form toothache is present to our
thought, and whether much or little of the rest of the
mind be filled at the same time. Thereupon of course
comes up the paradox and mystery : If the knowledge of
toothache be pent up in this separate mental pocket, how
can it be known cum alio or brought into one view with
anything else ? This pocket knows nothing else ; no other
part of the mind knows toothache. The knowing of tooth-
ache cum olio must be a miracle. And the miracle must
have an Agent. And the Agent must be a Subject or Ego
* out of time,' — and all the rest of it, as we saw in Chapter
X. And then begins the well-worn round of recrimination
between the sensationalists and the spiritualists, from which
we are saved by our determination from the outset to accept
the psychological point of view, and to admit knowledge
whether of simple toothaches or of philosophic systems as
an ultimate fact. There are realities and there are * states
of mind,' and the latter know the former ; and it is just as
wonderful for a state of mind to be a * sensation ' and know
a simple pain as for it to be a thought and know a system
but that this sensation, in consequence of practice and experience, is differ-
ently interpreted the last time, and elaborated into a different perception
from the first. For the only real data are, on the one hand, the physical
picture on the retina, — and that is both times the same; and, on the other
hand, the resultant state of consciousness (ausgeloste Empfindungscomplex)
— and that is both times distinct. Of any third thing, namely, a pure sen-
sation thrust between ths retinal and the mental pictures, we know nothing.
Wg can then, if we wish to avoid all hypothesis, only say that the nerwiis appa-
.4ttus reacts upon ths samie stimulus differently the last time from the first, and
that in consequence ike consciousness is different too." (Hermann's Hdbch.,
m. I. 567-8.)
6 PB70H0L0QT.
of related things.* But there is no reason to suppose that
when different states of mind know different things about
the same toothache, they do so by virtue of their all con-
taining faintly or vividly the original pain. Quite the re-
verse. The by-gone sensation of my gout was painful, as
Keid somewhere says ; the thoitght of the same gout as by-
gone is pleasant, and in no respect resembles the earlier
mental state.
Sensations, then, first make us acquainted with innu-
merable things, and then are replaced by thoughts which
know the same things in altogether other ways. And
Locke's main doctrine remains eternally true, however
hazy some of his language may have been, that
'' though there be a great number of considerations wherein things may
be compared one with another, and so a multitude of relations ; yet
they all terminate in, and are concerned about, those simple ideas f
either of sensation or reflection, which I think to be the whole materials
of all our knowledge. . . . The simple ideas we receive from sensation
and reflection are the boundaries of our thoughts ; beyond which, the
mind whatever efforts it would make, is not able to advance one jot ; nor
can it make any discoveries when it would pry into the nature and
hidden causes of those ideas." J
The nature and hidden causes of ideas will never be
unravelled till the nexics between the brain and conscious-
ness is cleared up. All we can say now is that sensations
a,re Jirst things in the way of consciousness. Before con-
ceptions can come, sensations must have come ; but before
sensations come, no psychic fact need have existed, a nerve-
current is enough. If the nerve-current be not given,
nothing else will take its place. To quote the good Locke
again:
'*It is not in the power of the most exalted wit or enlarged under-
standing, by any quickness or variety of thoughts, to invent or frame
* Yet even writers like Prof. Bain will deny, in the most gratuitous
way, that sensations know anything. "It is evident that the lowest or
most restricted form of sensation does not contain an element of knowl-
edge. The mere state of mind called the sensation of scarlet is not knowl-
edge, although a necessary preparation for it. " ' Is not knowledge about
scarlet ' is all that Professor Bain can rightfully say.
f By simple ideas of sensation Locke merely means sensations.
i Btsay c. H. U., bk. n. ch. xxm. § 29 ; oh. xxv. § ft.
SENSATION. 7
one new simple idea [i.e. sensation] in the mind. ... I would have
any one try to fancy any taste which had never affected his palate, or
frame the idea of a scent he had never smelt ; and when he can do this,
I will also conclude that a blind man hath ideas of colors, and a deaf
man true distinct notions of sounds." *
The brain is so made that all currents in it run one way.
Consciousness of some sort goes with all the currents, but
it is only when new currents are entering that it has the
sensational tang. And it is only then that consciousness
directly encounters (to use a word of Mr. Bradley's) a real-
ity outside itself.
The difference between such encounter and all concep-
tual knowledge is very great. A blind man may know all
about the sky's blueness, and I may know all about your
toothache, conceptually ; tracing their causes from primeval
chaos, and their consequences to the crack of doom. But
so long as he has not felt the blueness, nor I the toothache,
our knowledge, wide as it is, of these realities, will be hollow
and inadequate. Somebody must feel blueness, somebody
must have toothache, to make human knowledge of these
matters real. Conceptual systems which neither began nor
left off in sensations would be like bridges without piers.
Systems about fact must plunge themselves into sensation
as bridges plunge their piers into the rock. Sensations are
the stable rock, the terminus a quo and the terminus ad quern
of thought. To find such termini is our aim with all our
theories — to conceive first when and where a certain sensa-
tion may be had, and then to have it. Finding it stops dis-
cussion. Failure to find it kills the false conceit of
knowledge. Only when you deduce a possible sensation
for me from your theory, and give it to me when and where
the theory requires, do I begin to be sure that your thought
has anything to do with truth.
Pure sensations can only he realized in the earliest days of life.
They are all but impossible to adults with memories and
stores of associations acquired. Prior to all impressions
on sense-organs the brain is plunged in deep sleep and con-
sciousness is practically non-existent. Even the first weeks
* Op. cit. bk. II. ch. n. § 2.
8 PaYCHOLOQT.
after birth are passed in almost unbroken sleep by human
infants. It takes a strong message from the sense-organs to
break this slumber. In a new-born brain this gives rise to
an absolutely pure sensation. But the experience leaves
its * unimaginable touch ' on the matter of the convolutions,
and the next impression which a sense-organ transmits
produces a cerebral reaction in which the awakened vestige
of the last impression plays its part. Another sort of feel-
ing and a higher grade of cognition are the consequence ;
and the complication goes on increasing till the end of life,
no two successive impressions falling on an identical brain,
and no two successive thoughts being exactly the same.
(See above, p. 230 ff.)
The first sensation which an infant gets is for him the Uni-
verse. And the Universe which he later comes to know is
nothing but an amplification and an implication of that first
simple germ which, by accretion on the one hand and in-
tussusception on the other, has grown so big and complex
and articulate that its first estate is unrememberable. In
his dumb awakening to the consciousness of something there,
a mere this as yet (or something for which even the term
this would perhaps be too discriminative, and the intellec-
tual acknowledgment of which would be better expressed
by the bare interjection * lo ! '), the infant encounters an ob-
ject in which (though it be given in a pure sensation) all
the * categories of the understanding ' are contained. It has
objectivity f unity ^ suhstantialityy causality y in the full sense in
which any later object or system of objects has these things.
Here the young knower meets and greets his world ; and
the miracle of knowledge bursts forth, as Voltaire says, as
much in the infant's lowest sensation as in the highest
achievement of a Newton's brain. The physiological con-
dition of this first sensible experience is probably nerve-
currents coming in from many peripheral organs at once.
Later, the one confused Fact which these currents cause to
appear is perceived to be many facts, and to contain many
qualities.* For as the currents vary, and the brain-paths
* "So far is it from being true that we necessarily have as many feel-
ings in consciousness at one time as there are inlets to the sense then played
upon, that it is a fundamental law of pure sensation that each momentary
SENSATION.
are moulded by them, other thoughts with other * objects *
come, and the * same thing ' which was apprehended as a
present this soon figures as a past thxitf about which many
unsuspected things have come to light. The principles of
this development have been laid down already in Chapters
XII and XIII, and nothing more need here be added to
that account.
"THE BEIiATIVITY OF KNOWLEDGE.'*
To the reader who is tired of so much Erkenntnisstheoric
I can only say that I am so myself, but that it is indispen-
sable, in the actual state of opinions about Sensation, to try
to clear up just what the word means. Locke's pupils seek
to do the impossible with sensations, and against them we
must once again insist that sensations * clustered together '
cannot build up our more intellectual states of mind.
Plato's earlier pupils used to admit Sensation's existence,
grudgingly, but they trampled it in the dust as something
corporeal, non-cognitive, and vile.* His latest followers
state of the organism yields but one f eeliug, however numerous may be its
parts and its exposures. . . . To this originalUnity of consciousness it makes
no difference that the tributaries to the single feeling are beyond the organ,
ism instead of within it, in an outside object with several sensible proper-
ties, instead of in the living body with its several sensitive functions. . . .
The unity therefore is not made by ' association ' of several components;
but the plurality is formed by dissociation of unsuspected varieties within
the unity ; the substantive thing being no product of synthesis, but the
residuum of differentiation. " (J. Martineau : A Study of Religion (1888),
p. 192-4.) Compare also F. H. Bradley, Logic, book i. chap. ii.
* Such passages as the following abound in anti-sensationalist literature:
''- Sense is a kind of dull, confused, and stupid perception obtruded upon
the soul from without, whereby it perceives the alterations and motions
within its own body, and takes cognizance of individual bodies existing
rouud about it, but does not clearly comprehend what they are nor pene-
trate into the nature of them, it being intended by nature, as Plotinus speaks,
not so properly for knowledge as for the use of the body. For -he soul suf-
fering under that which it perceives by way of passion cannot master or
Oonquer it, that is to say, know or understand it. For so Anaxagoras in Aris-
totle very fitly expresses the nature of knowledge and intellection under
the notion of Conquering. Wherefore it is necessary, since the mind under-
atands all things, that it should be free from mixture and passion, for this
end, as Anaxagoras speaks, that it may be able to master and conquer its
objects, that is to say, to know and undei'stand them. In like manner Plo-
tinus, in his book of Sense and Memory, makes to suffer and to be conquered
ttll one, as also to know and to conquer; for which reason he oonqludet that
10 PSTCHOLOOT.
Beem to seek to crowd it out of existence altogether. The
only reals for the neo-Hegelian writers appear to be rda-
tionSy relations without terms, or whose terms are only
speciously such and really consist in knots, or gnarls of
relations finer still in infinitum.
"Exclude from what we have considered real all qualities consti-
tuted by relation, we find that none are left," "Abstract the many
relations from the one thing and there is nothing. . . . Without the
relations it would not exist at all." * "The single feeling is nothing
that which suffers doth not know. . . . 8ense that suffers from external
objects lies as it were prostrate under them, and is overcome by them.
. . . Sense therefore is a certain kind of drowsy and somnolent percep-
tion of that passive part of the soul which is as it were asleep in the body,
and acts concretely with it. . . . It is an energy arising from the body and
a certain kind of drowsy or sleeping life of the soul blended together
with it. The perceptions of which compound, or of the soul as it were half
asleep and half awake, are confused, indistinct, turbid, and encumbered
cogitations very different from the energies of the noetical part, . . . which
are free, clear, serene, satisfactory, and awakened cogitations. That is to
say, knowledges." Etc., etc., etc. (R. Cud worth: Treatise concerning
Eternal and Immutable Morality, bk iii. chap, ii.) Similarly Male-
branche: "Theodore. — Oh, oh, Ariste! God knows pain, pleasure, warmth,
and the rest. But he does not feel these things. He knows pain, since he
knows what that modification of the soul is in which pain consists. He
knows it because he alone causes it in us (as I shall presently prove), and he
knows what he does. In a word, he knows it because his knowledge has
no bounds. But he does not feel it, for if so he would be unhappy. To
know pain, then, is not to feel it. Ariste. — That is true. But to feel it
is to know it, is it not ? Theodore.— No indeed, since God does not feel
it in the least, and yet he knows it perfectly. But in order not to quibble
about terms, if you will have it that to feel pain is to know it, agree at least
that it is not to know it clearly, that it is not to know it by light and by
evidence — in a word, that it is not to know its nature; in other words and to
speak exactly, it is not to know it at all. To feel pain, for example, is to
feel ourselves unhappy without well knowing either what we are or what
is this modality of our being which makes us unhappy. . . . Impose silence
on your senses, your imagination, and your passions, and you will hear the
pure voice of inner truth, the clear and evident replies of our common mas-
ter. Never confound the evidence which results from the comparison of
ideas with the liveliness of the sensations which touch and thrill you. The
livelier our sensations and feelings {sentiments) are, the more darkness do
they shed. The more terrible or agreeable are our phantoms, and the more
body and reality they appear to have, the more dangerous are they and fit
to lead us astray." (Entretiens sur la Metaphysique, 3me Entretien, od
init.) Malebranche's Theodore prudently does not try to explain how
God's ' infinite felicity ' Is compatible with his not feeling joy.
* Green: Prolegomena, §§ 30, 38.
SENSATION. 11
real." ** On the recognition of relations as constituting the nature of
ideas, rests the possibility of any tenable theory of their reality."
Such quotations as these from the late T. H. Green*
would be matters of curiosity rather than of importance,
were it not that sensationalist writers themselves believe in
a so-called * Eelativity of Knowledge,' which, if they only
understood it, they would see to be identical with Professor
Green's doctrine. They tell us that the relation of sensa-
tions to each other is something belonging to their essence,
and that no one of them has an absolute content :
"That, e.g., black can only be felt in contrast to white, or at least
in distinction from a paler or a deeper black; similarly a tone or a sound
only in alternation with others or with silence; and in like manner a
smell, a taste, a touch, only, so to speak, in statu nascendi, whilst, when
the stimulus continues, all sensation disappears. This all seems at first
sight to be splendidly consistent both with itself and with the facts.
But looked at more closely, it is seen that neither is the case." t
* Introd. to Hume, §§ 146, 188. It is hard to tell just what this aposto-
lic human being but strenuously feeble writer means by relation Some-
times it seems to stand for system of related fact. The ubiquity of the
' psychologist's fallacy ' (see p. 19G) in his pages, his incessant leaning on
the confusion between the thing known, the thought that knows it, and the
farther things known about that thing and about that thought by later and
additional thoughts, make it impossible to clear up his meaning. Compare,
however, with the utterances in the text such others as these: " The wak-
ing of Self-consciousness from the sleep of sense is an absolute new begin-
ning, and nothing can come within the * crystal sphere ' of intelligence
except as it is determined by intelligence. What sense Is to sense is noth-
ing for thought. What sense is to thought, it is as determined by thought.
There can, therefore, be no ' reality Mn sensation to which the world of
thought can be referred." (Edward Caird's Philosophy of Kant, 1st ed.
pp. 393-4.) **When," says Green again, " feeling a pain or pleasure of
heat, I perceive it to be connected with the action of approaching the fire,
am I not perceiving a relation of which one constituent, at any rate, is a
simple sensation ? The true answer is, No." "Perception, in its simplest
form . . . — perception as the first sight or touch of an object in which
nothing but what is seen or touched is recognized — neither is nor contains
sensation" (Contemp. Rev., xxxi. pp. 746, 750.) "Mere sensation is in
truth a phrase that represents no reality." " Mere feeling, then, as a mat.
ter unformed by thought, has no place in the world of facts, In the cosmos
of possible experience." (Prolegomena to Ethics, §§ 46, 50.) — I have ex-
pressed myself a little more fully on this subject in Mind, x. 27 ff.
f Stumpf: Tonpsychologie, i. pp. 7, 8. Hobbes's phT&ae, sentire semper
idem et non sentire ad idem recidunt, is generally treated as the original state-
ment of the relativity doctrine. J. S. Mill (Examn. of Hamilton, p. 6)
12 PSTOHOLOQT.
The two leading facts from which the doctrine of uni-
versal relativity derives its wide-spread credit are these :
1) The psychological faxit that so much of our actual
knowledge is of the relations of things — even our simplest
sensations in adult life are habitually referred to classes
as we take them in ; and
2) The physiological fact that our senses and brain must
have periods of change and repose, else we cease to feel and
think.
Neither of these facts proves anything about the
presence or non-presence to our mind of absolute quali-
ties with which we become sensibly acquainted. Surely
not the psychological fact ; for our inveterate love of
relating and comparing things does not alter the intrin-
sic qualities or nature of the things compared, or undo
their absolute givenness. And surely not the physio-
logical fact ; for the length of time during which we can
feel or attend to a quality is altogether irrelevant to the
intrinsic constitution of the quality felt. The time, more-
over, is long enough in many instances, as sufferers from
neuralgia know.* And the doctrine of relativity, not proved
by these facts, is flatly disproved by other facts even more
patent. So far are we from not knowing (in the words of
Professor Bain) " any one thing by itself, but only the dif-
ference between it and another thing," that if this were true
the whole edifice of our knowledge would collapse. If all
we felt were the difference between the G and D, or c and c?,
on the musical scale, that being the same in the two pairs
of notes, the pairs themselves would be the same, and lan-
guage could get along without substantives. But Professor
Bain does not mean seriously what he says, and we need
spend no more time on this vague and popular form of the
doctrine, t The facts which seem to hover before the minds
and Bain (Senses and Intellect, p. 321; Emotions and Will, pp. 550. 570-2,
Logic, I. p. 2; Body and Mind, p. 81) are subscribers to this doctrine. Cf.
also J. MilPs Analysis, J. S. Mill's edition, ii. 11, 12.
* We can steadily hear a note for half an hour. The differences be-
tween the senses are marked. Smell and taste seem soon to get fatigued.
f In the popular mind it is mixed up with that entirely different doc-
trine of the • Relativity of Knowledge ' preached by Hamilton and Spencer.
This doctrine says that our knowledge is relative to us, and is not of the
8BN8ATI0N, 13
of its champions are those which are best described under
the head of a physiological law.
THE LAW OF CONTRAST.
I will first enumerate the main facts which fall under
this law, and then remark upon what seems to me their sig-
nificance for psychology.*
[Nowhere are the phenomena of contrast better exhib-
ited, and their laws more open to accurate study, than in
connection with the sense of sight. Here both kinds —
simultaneous and successive — can easily be observed, for
they are of constant occurrence. Ordinarily they remain
unnoticed, in accordance with the general law of economy
which causes us to select for conscious notice only such
elements of our object as will serve us for aesthetic or prac-
tical utility, and to neglect the rest ; just as we ignore the
double images, the moiwlies volantes, etc., which exist for
everyone, but which are not discriminated without careful
attention. But by attention we may easily discover the
general facts involved in contrast. We find that in general
the color and brightness of one object always apparently affect the
color and brightness of any other object seen simultaneously with
it or immediately after.
In the first place, if we look for a moment at any surface
and then turn our eyes elsewhere, the complementary color
and opposite degree of brightness to that of the first surface
tend to mingle themselves with the color and the brightness
of the second. This is svjccessive contrast It finds its ex-
planation in the fatigue of the organ of sight, causing it to
respond to any particular stimulus less and less readily the
longer such stimulus continues to act. This is shown clearly
in the very marked changes which occur in case of contin-
ued fixation of one particular point of any field. The field
darkens slowly, becomes more and more indistinct, and
finally, if one is practised enough in holding the eye per-
object as the latter is in itself. It has nothing to do with the question
which we have been discussing, of whether our objects of knowledge con-
tain absolute terms or consist altogether of relations.
* What follows in brackets, as far as p. 37, is from the pen of my friend
and pupil Mr. E. B. Delabarre.
14 P87CH0L0OY.
fectly steady, slight differences in shade and color may
entirely disappear. If we now turn aside the eyes, a nega-
tive after-image of the field just fixated at once forms, and
mingles its sensations with those which may happen to
come from anything else looked at. This influence is dis-
tinctly evident only when the first surface has been * fixated '
without movement of the eyes. It is, however, none the
less present at all times, even when the eye wanders from
point to point, causing each sensation to be modified more
or less by that just previously experienced. On this ac-
count successive contrast is almost sure to be present in
cases of simultaneous contrast, and to complicate the
phenomena.
A visual image is modified not only by other sensations just
previously experienced, hut also by all those experienced simul-
taneously ivith it, and especially by such as proceed from con-
tiguous portions of the retina. This is the phenomenon of
simultaneous contrast. In this, as in successive contrast, both
brightness and hue are involved. A bright object appears
still brighter when its surroundings are darker than itself,
and darker when they are brighter than itself. Two colors
side by side are apparently changed by the admixture, with
each, of the complement of the other. And lastly, a gray
surface near a colored one is tinged with the complement
of the latter.*
The phenomena of simultaneous contrast in sight are so
complicated by other attendant phenomena that it is diffi-
* These phenomena have close analogues in the phenomena of contrast
presented by the temperature-sense (see W. Preyer in Archiv f. d. ges.
Phys., Bd. XXV. p. 79 ff.). Successive contrast here is shown in the fact
that a warm sensation appears warmer if a cold one has just previously
been experienced ; and a cold one colder, if the preceding one was warm.
If a finger which has been plunged in hot water, and another which has
been in cold water, be both immersed in lukewarm water, the same water
appears cold to the former finger and warm to the latter. In simultaneous
contrast, a sensation of warmth on any part of the skin tends to induce the
sensation of cold in its immediate neighborhood ; and vice versd. This
may be seen if we press with the palm on two metal surfaces of about an
inch and a half square and three-fourths inch apart ; the skin between them
appears distinctly warmer. So also a small object of exactly the tempera-
ture of the palm appears warm if a cold object, and cold if a warm object,
touch the skin near it.
SENSATION. Ifi
cult to isolate them and observe them in their purity. Yet
it is evidently of the greatest importance to do so, if one
would conduct his investigations accurately. Neglect of
this principle has led to many mistakes being made in
accounting for the facts observed. As we have seen, if the
eye is allowed to wander here and there about the field as
it ordinarily does, successive contrast results and allowance
must be made for its presence. It can be avoided only by
carefully fixating with the well-rested eye a point of one
field, and by then observing the changes which occur in
this field when the contrasting field is placed by its side.
Such a course will insure pure simultaneous contrast. But
even thus it lasts in its purity for a moment only. It
reaches its maximum of effect immediately after the intro-
duction of the contrasting field, and then, if the fixation is
continued, it begins to weaken rapidly and soon disappears ;
thus undergoing changes similar to those observed when
any field whatever is fixated steadily and the retina becomes
fatigued by unchanging stimuli. If one continues still
further to fixate the same point, the color and brightness
of one field tend to spread themselves over and mingle with
the color and brightness of the neighboring fields, thus
substituting ' simultaneous indiKition ' for simultaneous con-
trast.
Not only must we recognize and eliminate the effects of
successive contrast, of temporal changes due to fixation,
and of simultaneous induction, in analyzing the phenomena
of simultaneous contrast, but we must also take into account
various other influeTwes which modify its effects. Under favor-
able circumstances the contrast-effects are very striking,
and did they always occur as strongly they could not fail
to attract the attention. But they are not always clearly
apparent, owing to various disturbing causes which form no
exception to the laws of contrast, but which have a. modi-
fying effect on its phenomena. When, for instance, the
ground observed has many distinguishable features — a
coarse grain, rough surface, intricate pattern, etc. — the con-
trast effect appears weaker. This does not imply that the
effects of contrast are absent, but merely that the resulting
sensations are overpowered by the many other stronger sen-
16 PBTCHOLOGY.
sations which entirely occupy the attention. On such a
ground a faint negative after-image — undoubtedly due to
retinal modifications — may become invisible ; and even
weak objective differences in color may become imper-
ceptible. For example, a faint spot or grease-stain on
woollen cloth, easily seen at a distance, when the fibres are
not distinguishable, disappears when closer examination
reveals the intricate nature of the surface.
Another frequent cause of the apparent absence of con-
trast is the presence of narrow dark intermediate fields, such
as are formed by bordering a field with black lines ^ or by the
shaded contours of objects. When such fields interfere with
the contrast, it is because black and white can absorb much
color without themselves becoming clearly colored ; and
because such lines separate other fields too far for them to
distinctly influence one another. Even weak objective
differences in color may be made imperceptible by such
means.
A third case where contrast does not clearly appear is
where the color of the contrasting fields is too weak or too in-
tense, or where there is mmih differewie in brightness between the
tivo fields. In the latter case, as can easily be shown, it is
the contrast of brightness which interferes with the color-
contrast and makes it imperceptible. For this reason con-
trast shows best between fields of about equal brightness.
But the intensity of the color must not be too great, for then
its very darkness necessitates a dark contrasting field which
is too absorbent of induced color to allow the contrast to
appear strongly. The case is similar if the fields are too
light.
To obtain the best contrast-effects, therefore, the contrasting
fields shotdd be near together, should not be separated by shadows
or black lines, should be of homogeneous texture, and should be of
about equal brightness and medium intensity of color. Such
conditions do not often occur naturally, the disturbing in-
fluences being present in case of almost all ordinary objects,
thus making the effects of contrast far less evident. To
eliminate these disturbances and to produce the conditions
most favorable for the appearance of good contrast- effects,
I
8ENSATI0K 17
various experiments have been devised, which will be ex-
plained in comparing the rival theories of explanation.
There are two theories — the psychological and the physio-
logical — which attempt to explain the phenomena of con-
trast.
Of these the psychological one was the first to gain prom-
inence. Its most able advocate has been Hdmholtz, It explains
contrast as a deception of judgment. In ordinary life our
sensations have interest for us only so far as they give
us practical knowledge. Our chief concern is to recognize
objects, and we have no occasion to estimate exactly their
absolute brightness and color. Hence we gain no facility
in so doing, but neglect the constant changes in their shade,
and are very uncertain as to the exact degree of their
brightness or tone of their color. When objects are near
one another " we are inclined to consider those differences
which are clearly and surely perceived as greater than
those which appear uncertain in perception or which must
be judged by aid of memory," * just as we see a medium-
sized man taller than he really is when he stands beside a
short man. Such deceptions are more easily possible in
the judgment of small differences than of large ones ;
also where there is but one element of difference instead of
many. In a large number of cases of contrast, in all
of which a whitish spot is surrounded on all sides by
a colored surface — Meyer's experiment, the mirror experi-
ment, colored shadows, etc., soon to be described — the
contrast is produced, according to Helmholtz, by the fact
that " a colored illumination or a transparent colored cover-
ing appears to be spread out over the field, and obser-
vation does not show directly that it fails on the white
spot." t We therefore believe that we see the latter
through the former color. Now
" Colors have their greatest importance for us in so far as they are
properties of bodies and can serve as signs for the recognition of
bodies. . . . We have become accustomed, in forming a judgment in
regard to the colors of bodies, to eliminate the varying brightness and
* Helmholtz, Physiolog. Optik, p. 392.
t Loc. cit. p. 407.
18 PSTCHOLOGT.
color of the illumination. We have sufficient opportunity to investigate
the same colors of objects in full sunshine, in the blue light of the clear
sky, in the weak white light of a cloudy day, in the reddish-yellow light
of the sinking sun or of the candle. Moreover the colored reflections
of surrounding objects are involved. Since we see the same colored
objects under these varying illuminations, we learn to form a correct
conception of the color of the object in spite of the difference in illumi-
nation, i.e. to judge how such an object would appear in white illumi-
nation ; and since only the constant color of the object interests us,
we do not become conscious of the particular sensations on which our
judgment rests. So also we are at no loss, when we see an object
through a colored covering, to distinguish what belongs to the color of
the covering and what to the object. In the experiments mentioned we
do the same also where the covering over the object is not at all colored,
because of the deception into which we fall, and in consequence of which
we ascribe to the body a false color, the color complementary to the
colored portion of the covering. " *
We think that we see the complementary color through
the colored covering, — for these two colors together would
give the sensation of white which is actually experienced.
If, however, in any way the white spot is recognized as an
independent object, or if it is compared with another ob-
ject known to be white, our judgment is no longer deceived
and the contrast does not appear.
''As soon as the contrasting field is recognized as an independent
body which hes above the colored ground, or even through an ade-
quate tracing of its outlines is seen to be a separate field, the contrast
disappears. Since, then, the judgment of the spatial position, the
material independence, of the object in question is decisive for the
determination of its color, it follows that the contrast-color arises not
through an act of sensation but through an act of judgment." f
In short, the apparent change in color or brightness
through contrast is due to no change in excitation of the
organ, to no change in sensation ; but in consequence of a
false judgment the unchanged sensation is wrongly inter-
preted, and thus leads to a changed perception of the bright-
ness or color.
In opposition to this theory has been developed one
which attempts to explain all cases of contrast as depend-
* Loc. cit. p. 408.
f Loc. cit. p. 406.
8BN8ATI0N. 19
ing purely on physiological action of the terminal apparatus of
vision. Hering is the most prominent supporter of this view.
By great originality in devising experiments and by insist-
ing on rigid care in conducting them, he has been able to
detect the faults in the psychological theory and to practi-
cally establish the validity of his own. Every visual sensa-
tion, he maintains, is correlated to a physical process in the
nervous apparatus. Contrast is occasioned, not by a false
idea resulting from unconscious conclusions, but by the
fact that the excitation of any portion of the retina — and
the consequent sensation — depends not only on its own
illumination, but on that of the rest of the retina as well.
" If this psycho-physical process is aroused, as usually happens, by
light-rays impinging on the retina, its nature depends not only on the
nature of these rays, but also on the constitution of the entire nervous
apparatus which is connected with the organ of vision, and on the state
in which it finds itself." *
When a limited portion of the retina is aroused by ex-
ternal stimuli, the rest of the retina, and especially the
immediately contiguous parts, tends to react also, and in
such a way as to produce therefrom the sensation of the
opposite degree of brightness and the complementary color
to that of the directly-excited portion. When a gray spot
is seen alone, and again when it appears colored through
contrast, the objective light from the spot is in both cases
the same. Helmholtz maintains that the neural process
and the corresponding sensation also remain unchanged, but
are differently interpreted ; Hering, that the neural process
and the sensation are themselves changed, and that the
' interpretation ' is the direct conscious correlate of the
altered retinal conditions. According to the one, the con-
trast is psychological in its origin ; according to the other,
it is purely physiological. In the cases cited above where
the contrast-color is no longer apparent — on a ground with
many distinguishable features, on a field whose borders are
traced with black lines, etc., — the psychological theory, as
we have seen, attributes this to the fact that under these
circumstances we judge the smaller patch of color to be an
* E. Hering, in Hermann's Haudbucb d. Physiologie, in. 1, p. 665.
20 PSYCHOLOGY.
independent object on the surface, and are no longer de-
ceived in judging it to be something over which the color
of the ground is drawn. The physiological theory, on the
other hand, maintains that the contrast-effect is still pro-
duced, but that the conditions are such that the slight
changes in color and brightness which it occasions become
imperceptible.
The two theories, stated thus broadly, may seem equally
plausible. Hering, however, has conclusively proved, by
experiments with after-images, that the process on one part
of the retina does modify that on neighboring portions,
under conditions where deception of judgment is impossi-
ble."^ A careful examination of the facts of contrast will
show that its phenomena must be due to this cause. In all
the cases which one may investigate it will be seen that the up-
holders of the psychological theory have failed to condvxit their
experiments with sufficient care. They have not excluded
successive contrast, have overlooked the changes due to
* Hering : 'Zur Lehre vom Lichtsinne.'— Of these experiments the fol-
lowing (found on p. 24 ff.) may be cited as a typical one : "From dark
gray paper cut two strips 3-4 cm. long and | cm. wide, and lay them on a
background of which one half is white and the other half deep black, in
such a way that one strip lies on each side of the borderline and parallel
to it, and at least 1 cm. distant from it. Fixate i to 1 minute a point on
the border-line between the strips. One strip appears much brighter than
the other. Close and cover the eyes, and the negative after-image appears.
. . . The difference in brightness of the strips in the after-image is in gen-
eral much greater than it appeared in direct vision. . . . This difference
in brightness of the strips by no means always increases and decreases with
the difference in brightness of the two halves of the background. ... A
phase occurs in which the difference in brightness of the two halves of
the background entirely disappears, and yet both after-images of the strips
are still very clear, one of them brighter and one darker than the back-
ground, which is equally bright on both halves. Here can no longer be
any question of contrast-effect, because the conditio sine qua non of con-
trast, namely, the differing brightness of the ground, is no longer pres-
ent. This proves that the different brightness of the after-images of the
strips must have its ground in a different state of excitation of the corre-
sponding portions of the retina, and from this follows further that botii
these portions of the retina were differently stimulated during the original
observation ; for the different after-effect demands here a different fore-
effect. ... In the original arrangement, the objectively similar strips
appeared of different brightness, because both corresponding portions of
the retina were truly differently excited. "
8EN8ATI0N. 21
steady fixation, and have failed to properly account for the
various modifying influences which have been mentioned
above. We can easily establish this if we examine the most
striking experiments in simultaneous contrast.
Of these one of the best known and most easily arranged
is that known as Meyer's experiment, A scrap of gray paper
is placed on a colored background, and both are covered
by a sheet of transparent white paper. The gray spot then
assumes a contrast-color, complementary to that of the
background, which shines with a whitish tinge through the
paper which covers it. Helmholtz explains the phenome-
non thus :
" If the background is green, the covering-paper itself appears to be
of a greenish color. If now the substance of the paper extends without
apparent interruption over the gray which lies under it, we think that
we see an object glimmering through the greenish paper, and such an
object must in turn be rose-red, in order to give white light. If, how-
ever, the gray spot has its limits so fixed that it appears to be an inde-
pendent object, the continuity with the greenish portion of the surface
fails, and we regard it as a gray object which lies on this surface." *
The contrast-color may thus be made to disappear by
tracing in black the outlines of the gray scrap, or by plac-
ing above the tissue paper another gray scrap of the same
degree of brightness, and comparing together the two grays.
On neither of them does the contrast- color now appear.
Hering t shows clearly that this interpretation is incor-
rect, and that the disturbing factors are to be otherwise
explained. In the first place, the experiment can be so
arranged that we could not possibly be deceived into be-
lieving that we see the gray through a colored medium.
Out of a sheet of gray paper cut strips 5 mm. wide in such
a way that there will be alternately an empty space and a
bar of gray, both of the same width, the bars being held to-
gether by the uncut edges of the gray sheet (thus presenting
an appearance like a gridiron). Lay this on a colored back-
ground — e.g. green — cover both with transparent paper,
and above all put a black frame which covers all the edges,
leaving visible only the bars, which are now alternately
* Helmholtz, Physiolog. Optik, p. 407.
t In Archiv f. d. ges. Physiol., Bd. xli. S. Iff.
22 PaYCHOLOOT.
green and gray. The gray bars appear strongly colored
by contrast, although, since they occupy as much space as
the green bars, we are not deceived into believing that we
see the former through a green medium. The same is true
if we weave together into a basket pattern narrow strips of
green and gray and cover them with the transparent paper.
Why, then, if it is a true sensation due to physiological
causes, and not an error of judgment, which causes the
contrast, does the color disappear when the outlines of the
gray scrap are traced, enabling us to recognize it as an
independent object ? In the first place, it does not neces-
sarily do so, as will easily be seen if the experiment is
tried. The contrast-color often remains distinctly visible
in spite of the black outlines. In the second place, there
are many adequate reasons why the effect should be modi-
fied. Simultaneous contrast is always strongest at the
border-line of the two fields ; but a narrow black field now
separates the two, and itself by contrast strengthens the
whiteness of both original fields, which were already little
saturated in color ; and on black .and on white, contrast-
colors show only under the most favorable circumstances.
Even weak objective differences in color may be made to
disappear by such tracing of outlines, as can be seen if we
place on a gray background a scrap of faintly- colored
paper, cover it with transparent paper and trace its out-
lines. Thus we see that it is not the recognition of the
contrasting field as an independent object which interferes
with its color, but rather a number of entirely explicable
physiological disturbances.
The same may be proved in the case of holding above the
tissue paper a second gray scrap and comparing it with that
underneath. To avoid the disturbances caused by using
papers of different brightness, the second scrap should
be made exactly like the first by covering the same gray
with the same tissue paper, and carefully cutting a piece
about 10 mm. square out of both together. To thoroughly
guard against successive contrast, which so easily compli-
cates the phenomena, we must carefully prevent all previ
ous excitation of the retina by colored light. This may be
done by arranging thus : Place the sheet of tissue paper
SENSATION. 28
on a glass pane, which rests on four supports ; under the
paper put the first gray scrap. By means of a wire, fasten
the second gray scrap 2 or 3 cm. above the glass plate.
Both scraps appear exactly alike, except at the edges
Gaze now at both scraps, with eyes not exactly accommo-
dated, so that they appear near one another, with a very
narrow space between. Shove now a colored field (green)
underneath the glass plate, and the contrast appears at
once on both scraps. If it appears less clearly on the
upper scrap, it is because of its bright and dark edges, its
inequalities, its grain, etc. When the accommodatiQn is
exact, there is no essential change, although then on the
upper scrap the bright edge on the side toward the light,
and the dark edge on the shadow side, disturb somewhat.
By continued fixation the contrast becomes weaker and
finally yields to simultaneous induction, causing the scraps
to become indistinguishable from the ground. Kemove
the green field and both scraps become green, by succes-
sive induction. If the eye moves about freely these last-
named phenomena do not appear, but the contrast continues
indefinitely and becomes stronger. When Helmholtz found
that the contrast on the lower scrap disappeared, it was
evidently because he then really held the eye fixed. This
experiment may be disturbed by holding the upper scrap
wrongly and by the differences in brightness of its edges,
or by other inequalities, but not by that recognizing of it
* as an independent body lying above the colored ground,'
on which the psychological explanation rests.
In like manner the claims of the psychological explana-
tion can be shown to be inadequate in other cases of con-
trast. Of frequent use are revolving disks, which are
especially efficient in showing good contrast-phenomena,
because all inequalities of the ground disappear and leave
a perfectly homogeneous surface. On a white disk are ar-
ranged colored sectors, which are interrupted midway by
narrow black fields in such a way that when the disk is re-
volved the white becomes mixed with the color and the
black, forming a colored disk of weak saturation on which
appears a gray ring. The latter is colored by contrast with
24 PaYOHOLOOY.
the field which surrounds it. Helmholtz explains the fact
thus :
" The difference of the compared colors appears greater than it really
is either because this difference, when it is the only existing one and
draws the attention to itself alone, makes a stronger impression than
when it is one among many, or because the different colors of the sur-
face are conceived as alterations of the one ground-color of the surface
such as might arise through shadows falling on it, through colored
reflexes, or through mixture with colored paint or dust. In truth, to
produce an objectively gray spot on a green surface, a reddish coloring
would be necessary." *
This explanation is easily proved false by painting the
disk with narrow green and gray concentric rings, and giv-
ing each a different saturation. The contrast appears
though there is no ground-color, and no longer a single dif-
ference, but many. The facts which Helmholtz brings for-
ward in support of his theory are also easily turned against
him. He asserts that if the color of the ground is too in-
tense, or if the gray ring is bordered by black circles, the
contrast becomes weaker ; that no contrast appears on a
white scrap held over the colored field ; and that the gray
ring when compared with such scrap loses its contrast-color
either wholly or in part. Hering points out the inaccuracy
of all these claims. Under favorable conditions it is impos-
sible to make the contrast disappear by means of black en-
closing lines, although they naturally form a disturbing
element ; increase in the saturation of the field, if disturb-
ance through increasing brightness-contrast is to be avoid-
ed, demands a darker gray field, on which contrast-colors
are less easily perceived ; and careful use of the white scrap
leads to entirely different results. The contrast-color does
appear upon it when it is first placed above the colored
field; but if it is carefully fixated, the contrast-color di-
minishes very rapidly both on it and on the ring, from causes
already explained. To secure accurate observation, all
complication through successive contrast should be avoided
thus : first arrange the white scrap, then interpose a gray
screen between it and the disk, rest the eye, set the wheel
in motion, fixate the scrap, and then have the screen re-
* Helmholtz, loc. cii. p. 412.
SENSATION. 26
moved. The contrast at once appears clearly, and its dis-
appearance through continued fixation can be accurately
watched.
Brief mention of a few other cases of contrast must suf-
fice. The so-called mirror experiment consists of placing
at an angle of 45° a green (or otherwise colored) pane of
glass, forming an angle with two white surfaces, one hori-
zontal and the other vertical. On each white surface is a
black spot. The one on the horizontal surface is seen through
the glass and appears dark green, the other is reflected
from the surface of the glass to the eye, and appears by
contrast red. The experiment may be so arranged that we
are not aware of the presence of the green glass, but think
that we are looking directly at a surface with green and red
spots upon it ; in such a case there is no deception of judg-
ment caused by making allowance for the colored medium
through which we think that we see the spot, and therefore
the psychological explanation does not apply. On exclud-
ing successive contrast by fixation the contrast soon disap-
pears as in all similar experiments.^
Colored shadows have long been thought to afford a con-
vincing proof of the fact that simultaneous contrast is
psychological in its origin. They are formed whenever an
opaque object is illuminated from two separate sides by
lights of different colors. When the light from one source
is white, its shadow is of the color of the other light, and
the second shadow is of a color complementary to that of
the field illuminated by both lights. If now we take a tube,
blackened inside, and through it look at the colored shadow,
none of the surrounding field being visible, and then have
the colored light removed, the shadow still appears colored,
although *the circumstances which caused it have disap-
peared.' This is regarded by the psychologists as con-
clusive evidence that the color is due to deception of judg-
ment. It can, however, easily be shown that the persistence
of the color seen through the tube is due to fatigue of the
retina through the prevailing light, and that when the
colored light is removed the color slowly disappears as the
* See Hering : Archiv. f . d. ges. Physiol. . Bd. xli. S. 868 ft
26 ParOHOLOOT.
equilibrium of the retina becomes gradually restored. When
successive contrast is carefully guarded against, the simul-
taneous contrast, whether seen directly or through the tube,
never lasts for an instant on removal of the colored field.
The physiological explanation applies throughout to all the
phenomena presented by colored shadows. *
If we have a small field whose illumination remains con-
stant, surrounded by a large field of changing brightness,
an increase or decrease in brightness of the latter results
in a corresponding apparent decrease or increase respect-
ively in the brightness of the former, while the large field
seems to be unchanged. Exner says :
" This illusion of sense shows that we are inclined to regard as con-
stant the dominant brightness in our field of vision, and hence to refer
the changing difference between this and the brightness of a limited field
to a change in brightness of the latter."
The result, however, can be shown to depend not on
illusion, but on actual retinal changes, which alter the sen-
sation experienced. The irritability of those portions of
the retina lighted by the large field becomes much reduced
in consequence of fatigue, so that the increase in brightness
becomes much less apparent than it would be without this
diminution in irritability. The small field, however, shows
the change by a change in the contrast-effect induced upon
it by the surrounding parts of the retina, f
The above cases show clearly that physiological processes,
and not deception of jvdgmentf are responsible for contrast of
color. To say this, however, is not to maintain that our
perception of a color is never in any degree modified by
our judgment of what the particular colored thing before us
may be. We have unquestionable illusions of color due to
wrong inferences as to what object is before us. Thus Yon
Kries:f speaks of wandering through evergreen forests cov-
ered with snow, and thinking that through the interstices of
the boughs he saw the deep blue of pine-clad mountains, cov-
*Hering: Archiv f. d. ges. Physiol., Bd. xl. S. 172 ff. ; Delabwre ;
A-merican Journal of Psychology, ii. 636.
t Bering : Archiv f . d. ges. Physiol., Bd. xli. S. 91 fl.
t Die Gesichtsempfindungen u. ihre Analyse, p. 138.
SENSATION. 27
ered with snow and lighted by brilliant sunshine ; whereas
what he really saw was the white snow on trees near by,
lying in shadow]. *
Such a mistake as this is undoubtedly of psychological
origin. It is a wrong classification of the appearances,
due to the arousal of intricate processes of association^
amongst which is the suggestion of a different hue from
that really before the eyes. In the ensuing chapters such
illusions as this will be treated of in considerable detail.
But it is a mistake to interpret the simpler cases of con-
trast in the light of such illusions as these. These illu-
sions can be rectified in an instant, and we then wonder
how they could have been. They come from insufficient
attention, or from the fact that the impression which we
get is a sign of more than one possible object, and can be
interpreted in either way. In none of these points do they
resemble simple color-contrast, which unquestionably is a
'phenomenon of sensation immediately aroused.
I have dwelt upon the facts of color-contrast at such
great length because they form so good a text to comment
on in my struggle against the view that sensations are im-
mutable psychic things which coexist with higher mental
functions. Both sensationalists and intellectualists agree
that such sensations exist. They fuse, say the pure sen-
sationalists, and mahe the higher mental function ; they
are combined by activity of the Thinking Principle, say the
intellectualists. I myself have contended that they do not
exist in or alongside of the higher mental function when
that exists. The things which arouse them exist ; and the
higher mental function also knows these same things. But
just as its knowledge of the things supersedes and displaces
their knowledge, so it supersedes and displaces them,
when it comes, being as much as they are a direct result-
ant of whatever momentary brain-conditions may obtain.
The psychological theory of contrast, on the other hand,
holds the sensations still to exist in themselves unchanged
before the mind, whilst the ' relating activity ' of the latter
* Mr. Delabarre'tt contribution ends here.
28 P8TGH0L0GT.
deals with them freely and settles to its own satisfaction
what each shall be, in view of what the others also are.
Wundt says expressly that the Law of Relativity is "not a
law of sensation but a law of Apperception ;" and the word
Apperception connotes with him a higher intellectual spon-
taneity.* This way of taking things belongs with the phi-
losophy that looks at the data of sense as something earth-
born and servile, and the * relating of them together' as
something spiritual and free. Lo ! the spirit can even
change the intrinsic quality of the sensible facts themselves
if by so doing it can relate them better to each other ! But
(apart from the difficulty of seeing how changing the sen-
sations should relate them better) is it not manifest that
the relations are part of the 'content' of consciousness,
part of the * object,' just as much as the sensations are?
Why ascribe the former exclusively to the knower and the
latter to the knoivn ? The hnoiver is in every case a unique
pulse of thought corresponding to a unique reaction of the
brain upon its conditions. All that the facts of contrast
show us is that the same real thing may give us quite
different sensations when the conditions alter, and that we
must therefore be careful which one to select as the thing's
truest representative.
There are many other facts beside the phenomena of contrast
which prove that when two objects act together on us the
sensation which either would give alone becomes a different
sensation. A certain amount of skin dipped in hot water
gives the perception of a certain heat. More skin immersed
makes the heat much more intense, although of course the
water's heat is the same. A certain extent as well as in-
tensity, in the quantity of the stimulus is requisite for any
quality to be felt. Tick and Wunderli could not distin-
guish heat from touch when both were applied through a
* Physiol. Psych., i. 351, 458-60. The full inanity of the law of rela-
tivity is best to be seen in Wundt's treatment, where the great ' allgemeiner
Oesetz der Beziehung,' inyoked lo account for Weber's law as well as for
the phenomena of contrast and many other matters, can only be defined as
a tendency to feel all things in relation to each other ! Bless its little soul I
But why does it change the things so, when it thus feels them in relation?
SENSATION. 29
hole in a card, and so confined to a small part of the skin.
Similarly there is a chromatic minimum of size in objects.
The image they cast on the retina must needs have a cer-
tain extent, or it will give no sensation of color at all. In-
versely, more intensity in the outward impression may
make the subjective object more extensive. This happens,
as will be shown in Chapter XIX, when the illumination
is increased : The whole room expands and dwindles ac-
cording as we raise or lower the gas-jet. It is not easy
to explain any of these results as illusions of judgment
due to the inference of a wrong objective cause for the sen-
sation which we get. No more is this easy in the case of
Weber's observation that a thaler laid on the skin of the
forehead feels heavier when cold than when warm ; or of
Szabadfoldi's observation that small wooden disks when
heated to 122° Fahrenheit often feel heavier than those
which are larger but not thus warmed ; * or of Hall's ob-
servation that a heavy point moving over the skin seems
to go faster than a lighter one moving at the same rate of
speed, t
Bleuler and Lehmann some years ago called attention
to a strange idiosyncrasy found in some persons, and con-
sisting in the fact that impressions on the eye, skin, etc.,
were accompanied by distinct sensations of sound.X Colored
hearing is the name sometimes given to the phenomenon,
which has now been repeatedly described. Quite lately the
Viennese aurist Urbantschitsch has proved that these cases
are only extreme examples of a very general law, and that
all our sense-organs influence each other's sensations.§
The hue of patches of color so distant as not to be recog-
nized was immediately, in U.'s patients, perceived when a
tuning-fork was sounded close to the ear. Sometimes, on
the contrary, the field was darkened by the sound. The
acuity of vision was increased, so that letters too far off to
be read could be read when the tuning-fork was heard.
Urbantschitsch, varying his experiments, found that their
* Ladd : Physiol. Psych., p. 348.
t Mind, X. 567.
X Zwangsmassige Lichtempfindung durch Schall (Leipzig, 1881).
§ Pflilger's Archiv, xlii. 154.
80 ParOHOLOQT.
results were mutual, and that sounds which were on the
limits of audibility became audible when lights of various
colors were exhibited to the eye. Smell, taste, touch, sense
of temperature, etc., were all found to fluctuate when lights
were seen and sounds were heard. Individuals varied much
in the degree and kind of effect produced, but almost every
one experimented on seems to have been in some way
affected. The phenomena remind one somewhat of the
* dynamogenic ' effects of sensations upon the strength of
muscular contraction observed by M. Fere, and later to be
described. The most familiar examples of them seem to be
the increase of pain by noise or light, and the increase of
nausea by all concomitant sensations. Persons suffering in
any way instinctively seek stillness and darkness.
Probably every one will agree that the best way of for-
mulating all such facts is physiological : it must be that the
cerebral process of the first sensation is reinforced or other-
wise altered by the other current which comes in. No one,
surely, will prefer a psychological explanation here. Well,
it seems to me that all cases of mental reaction to a plural-
ity of stimuli must be like these cases, and that the phy-
siological formulation is everywhere the simplest and the
best. When simultaneous red and green light make us see
yellow, when three notes of the scale make us hear a chord,
it is not because the sensations of red and of green and of
each of the three notes enter the mind as such, and there
* combine ' or ' are combined by its relating activity ' into
the yellow and the chord, it is because the larger sum of
light- waves and of air-waves arouses new cortical processes,
to which the yellow and the chord directly correspond.
Even when the sensible qualities of things enter into the
objects of our highest thinking, it is surely the same. Their
several sensations do not continue to exist there tucked
away. They are replaced by the higher thought which,
although a different psychic unit from them, knows the
same sensible qualities which they know.
The principles laid down in Chapter VI seem then to
be corroborated in this new connection. You cannot build
up one thought or one sensation out of many; and only direct
SENSATION. 81
experiment can inform us of what we shall perceive when we
gd "Albany stimuli at once.
THE ' ECCENTBIC PKOJBCTION ' OF SENSATI01\ %.
We often hear the opinion expressed that all our sensa-
tions at first appear to us as subjective or internal, and are
afterwards and by a special act on our part * extradited ' or
'projected' so as to appear located in an outer world.
Thus we read in Professor Ladd's valuable work that
" Sensations ... are psychical states whose place— so tsLV as they can
be said to have one — is the mind. The transference of these sensations
from mere mental states to physical processes located in the periphery
of the body, or to qualities of things projected in space external to the
body, is a mental act. It may rather be said to be a mental achie'vement
[cf. Cudworth, above, as to knowledge being co7iquering], for it is an act
which in its perfection results from a long and intricate process of de-
velopment. . . . Two noteworthy stages, or ' epoch-making ' achieve-
ments in the process of elaborating the presentations of sense, require
a special consideration. These are ' localization,^ or the transference
of the composite sensations from mere states of the mind to processes
or conditions recognized as taking place at more or less definitely fixed
points or areas of the body; and ' eccentric projection ' (sometimes called
' eccentric perception ') or the giving to these sensations an objective
existence (in the fullest sense of the word ' objective ') as qualities of
objects situated within a field of space and in contact with, or more or
less remotely distant from, the body." *
It seems to me that there is not a vestige of evidence for
this view. It hangs together with the opinion that our sen-
sations are originally devoid of all spatial content, f an
opinion which I confess that I am wholly at a loss to under-
stand. As I look at my bookshelf opposite I cannot frame
to myself an idea, however imaginary, of any feeling which
I could ever possibly have got from it except the feeling of
* Physioloj^ical Psychology, 385, 387. See also such passages as that in
Bain : The Senses and the Intellect, pp. 364-6.
+ ' ' Especially must we avoid all attempts, whether avowed or concealed,
to account for the spatial qualities of the presentations of sense by merely
describing tlvj qualities of the simple sensations and the modes of their
combination. It Is position and extension in space which constitutes the
7ery peculiarity of the objects as no longer mere sensations or affections of
the mind. As sensations, they are neither out of ourselves nor possessed of
iie qualities indicated by the word spread-out." (Ladd, op. cit. p. 391.)
82 PBTOHOLOQT,
the same big extended sort of outward fact which I now
perceive. So far is it from being true that our first way of
feeling things is the feeling of them as subjective or men-
tal, that the exact opposite seems rather to be the trutL
Our earliest, most instinctive, least developed kind of con-
sciousness is the objective kind ; and only as reflection be-
comes developed do we become aware of an inner world at
all. Then indeed we enrich it more and more, even to the
point of becoming idealists, with the spoils of the outer
world which at first was the only world we knew. But
subjective consciousness, aware of itself as subjective, does
not at first exist. Even an attack of pain is surely felt at
first objectively as something in space which prompts to
motor reaction, and to the very end it is located, not in the
mind, but in some bodily part.
" A sensation which should not awaken an impulse to move, nor
any tendency to produce an outward effect, would manifestly be use-
less to a living creature. On the principles of evolution such a sensa-
tion could never be developed. Therefore every sensation originally
refers to something external and independent of the sentient creature.
Rhizopods (according to Engeimann's observations) retract their pseudo-
podia whenever these touch foreign bodies, even if these foreign bodies
are the pseudopodia of other individuals of their own species, whilst
the mutual contact of their own pseudopodia is followed by no such
contraction. These low animals can therefore already feel an outer
world — even in the absence of innate ideas of causality, and probably
without any clear consciousness of space. In truth the conviction that
something exists outside of ourselves does not come from thought. It
comes from sensation; it rests on the same ground as our conviction of
our own existence. ... If we consider the behavior of new-born
animals, we never find them betraying that they are first of all con-
scious of their sensations as purely subjective excitements. We far
more readily incline to explain the astonishing certainty with which
they make use of their sensations (and which is an effect of adaptation
and inheritance) as the result of an inborn intuition of the outer world.
. . . Instead of starting from an original pure subjectivity of sensa-
tion, and seeking how this could possibly have acquired an object! v
signification, we must, on the contrary, begin by the possession of objec
tivity by the sensation and then show how for reflective consciousness
the latter becomes interpreted as an effect of the object, how in short
the original immediate objectivity becomes changed into a remote
one."*
* A. Riebl: Der Philosophischer Kriticismus, Bd. n. Theil n. p. 64
SENSATION. 33
Another confusion, much more common than the denial
of all objective character to sensations, is the assumption
that they are all originally located ^7^5^(ie the body and are pro-
jected outward by a secondary act. This secondary judg-
ment is always false, according to M. Taine, so far as the
place of the sensation itself goes. But it happens to hit a
real object which is at the point towards which the sensation
is projected ; so we may call its result, according to this
author, a veridical hollvxiination.'^ The word Sensation, to
* On Intelligence, part ii. bk. ii. chap. ii. §g vii, viii. Compare such
statements as these : "The consequence is that when a sensation has for
its usual condition the presence of an object more or less distant from our
bodies, and experience has once made us acquainted with this distance, we
shall situate our sensation at this distance.— This, in fact, is the case
with sensations of hearing and sight. The peripheral extremity of the
acoustic nerve is in the deep-seated chamber of the ear. That of the
optic nerve is in the most inner recess of the eye. But still, in our
present state, we never situate our sensations of sound or color in these
places, but without us, and often at a considerable distance from us. . . .
All our sensations of color are thus projected out of our body, and clothe
more or less distant objects, furniture, walls, houses, trees, the sky, and the
rest. This is why, when we afterwards reflect on them, we cease to at-
tribute them to ourselves; they are alienated and detached from us, so fai
as to appear different from us. Projected from the nervous surface in
which we localize the majority of the others, the tie which connected
them to the others and to ourselves is undone. . . . Thus, all our sensa-
tions are wrongly situated, and the red color is no more extended on the
arm chair than the sensation of tingling is situated at my fingers* ends.
They are all situated in the sensory centres of the encephalon; all appear
situated elsewhere, and a common law allots to each of them its apparent
situation." (Vol. II. pp. 47-53.) — Similarly Schopenhauer: "I will now
show the same by the sense of sight. The immediate datum is here
limited to the sensation of the retina which, it is true, admits of con-
siderable diversity, but at bottom reverts to the impression of light
and dark with their shades, and that of colors. This sensation is
through and through subjective, that is, inside of the organism and
under the skin." (Schopenhauer: Satz vom Grunde, p. 58.) This philoso-
pher then enumerates seriatim what the Intellect does to make the origi-
nally subjective sensation objective: 1) it turns it bottom side up; 2) it
reduces its doubleness to singleness; 3) it changes its flatness to solidity; and
i) it projects it to a distance from the eye. Again: "Sensations are
what we call the impressions on our senses, in so far as they come to our
consciousness as states of our own body, especially of our nervous
apparatus; we call them perceptions when we form out of them the repre-
sentation of outer objects." (Helmholtz; Tonempfindungen, 1870, p. 101.)
—Once more : " Sensation is always accomplished in the psychic centres,
but it manifests itself at the excited part of the periphery. In other words,
34 P8TCH0L00Y.
begin with, is constantly, in psychological literature, used
as if it meant one and the same thing with the physical im-
pression either in the terminal organs or in the centres,
which is its antecedent condition, and this notwithstanding
that by sensation we mean a mental, not a physical, fact.
But those who expressly mean by it a mental fact still
leave to it a physical place, still think of it as objectively
inhabiting the very neural tracts which occasion its appear-
ance when they are excited ; and then (going a step farther)
they think that it must place itself where they place it, or be
subjectively sensible of that place as its habitat in the
first instance, and afterwards have to be moved so as to
appear elsewhere.
All this seems highly confused and unintelligible. Con-
sciousness, as we saw in an earlier chapter (p. 214) canno^
properly be said to inhabit any place. It has dynamic re-
lations with the brain, and cognitive relations with every-
thing and anything. From the one point of view we may
say that a sensation is in the same place with the brain (if
we like), just as from the other point of view we may say
that it is in the same place with whatever quality it may be
cognizing. But the supposition that a sensation primi-
tively /eeZs either itself or its object to be in the same place ivith
the brain is absolutely groundless, and neither a priori
probability nor facts from experience can be adduced to
show that such a deliverance forms any part of the original
cognitive function of our sensibility.
Where, then, do we feel the objects of our original sensa-
tions to be ?
Certainly a child newly born in Boston, who gets a sen-
sation from the candle-flame which lights the bedroom, or
from his diaper-pin, does not feel either of these objects to
one is conscious of the phenomenon in the nervous centres, . . . but one
perceives it in the peripheric organs. This phenomenon depends on the
experience of the sensations themselves, in which there is a reflection of
the subjective phenomenon and a tendency on the part of perception to
return as it were to the external cause which has roused the mental state
because the latter is connected with the former." (Sergi: Psychologic
Physiologique (Paris, 1888), p. 189.) — The clearest and best passage I know
is in Liebmann: Der Objective Anblick (1869), pp. 67-73, but it is unfortu
nately too long to quote.
SENSATION. 85
be situated in longitude 72° W. and latitude 41° N. He
does not feel them to be in the third story of the house. He
does not even feel them in any distinct manner to be to the
right or the left of any of the other sensations which he
may be getting from other objects in the room at the same
time. He does not, in short, know anything about their
space-relations to anything else in the world. The flame
fills its own place, the pain fills its own place ; but as yet
these places are neither identified with, nor discriminated
from, any other places. That comes later. For the places
thus first sensibly known are elements of the child's space-
world which remain with him all his life ; and by memory
and later experience he learns a vast number of things about
those places which at first he did not know. But to the
end of time certain places of the world remain defined for
him as the places where those sensations ivere ; and his only
possible answer to the question where anything is will be to
say * therey and to name some sensation or other like those
first ones, which shall identify the spot. Space means but
the aggregate of all our possible sensations. There is no
duplicate space known aliunde^ or created by an * epoch-
making achievement ' into which our sensations, originally
spaceless, are dropped. They bring space and all its places
to our intellect, and do not derive it thence.
By his body, then, the child later means simply that place
where the pain from the pin, and a lot of other sensations
like it, were or are felt. It is no more true to say that he
locates that pain in his body, than to say that he locates his
body in that pain. Both are true : that pain is part of what
he means by the word body. Just so by the outer world the
child means nothing more than that place where the candle-
flame and a lot of other sensations like it are felt. He no
more locates the candle in the outer world than he locates
the outer world in the candle. Once again, he does both ;
for the candle is part of what he means by * outer world.'
This (it seems to me) will be admitted, and will (I trust)
be made still more plausible in the chapter on the Percep-
tion of Space. But the later developments of this percep-
tion are so complicated that these simple principles get
86 PSTOHOLOOT.
easily overlooked. One of the complications comes from
the fact that things wove, and that the original object which
we feel them to be splits into two parts, one of which re-
mains as their whereabouts and the other goes off as their
quality or nature. We then contrast where they were with
where they are. If we do not move, the sensation of where
they were remains unchanged ; but we ourselves presently
move, so that that also changes ; and ' where they were '
becomes no longer the actual sensation which it was origi-
nally, but a sensation which we merely conceive as possible.
Gradually the system of these possible sensations, takes
more and more the place of the actual sensations. ' Up *
and * down ' become * subjective ' notions ; east and west
grow more * correct * than * right ' and * left ' etc.; and things
get at last more * truly ' located by their relation to certain
ideal fixed co-ordinates than by their relation either to
our bodies or to those objects by which their place was
originally defined. Now this revision of our original locali-
zations is a complex affair; and contains somefa^ts which may
very naturally come to he described as translocations whereby
sensations get shoved farther off than they originally appeared.
Few things indeed are more striking than the change-
able distance which the objects of many of our sensations
may be made to assume. A fly's humming may be taken
for a distant steam-whistle ; or the fly itself, seen out of
focus, may for a moment give us the illusion of a distant
bird. The same things seem much nearer or much farther,
according as we look at them through one end or another of
an opera-glass. Our whole optical education indeed is
largely taken up with assigning their proper distances to the
objects of our retinal sensations. An infant will grasp at the
moon ; later, it is said, he projects that sensation to a dis-
tance which he knows to be beyond his reach. In the
much quoted case of the * young gentleman who was born
blind,' and who was * couched ' for the cataract by Mr.
Chesselden, it is reported of the patient that " when he first
saw, he was so far from making any judgment about dis-
tances, that he thought all objects whatever touched his
eyes (as he expressed it) as what he felt did his skin."
And other patients born blind, but relieved by surgical op-
k
SENSATION. 91
eration, have been described as bringing their hand close
to their eyes to feel for the objects which they at first saw,
and only gradually stretching ont their hand when they
found that no contact occurred. Many have concluded
from these facts that our earliest visual objects must seem
in immediate contact with our eyes.
But tactile objects also may be affected with a like am-
biguity of situation.
If one of the hairs of our head be pulled, we are pretty
accurately sensible of the direction of the pulling by the
movements imparted to the head.^ But the feeling of the
pull is localized, not in that part of the hair's length which
the fingers hold, but in the scalp itself. This seems con-
nected with the fact that our hair hardly serves at all as a
tactile organ. In creatures with vibrissce^ however, and in
those quadrupeds whose whiskers are tactile organs, it can
hardly be doubted that the feeling is projected out of the
root into the shaft of the hair itself. We ourselves have an
approach to this when the beard as a whole, or the hair as
a whole, is touched. We perceive the contact at some dis-
tance from the skin.
When fixed and hard appendages of the body, like the
teeth and nails, are touched, we feel the contact where it
objectively is, and not deeper in, where the nerve-termina-
tions lie. If, however, the tooth is loose, we feel two
contacts, spatially separated, one at its root, one at its
top.
From this case to that of a hard body not organically
connected with the surface, but only accidentally in contact
with it, the transition is immediate. With the point of a
cane we can trace letters in the air or on a wall just as with
the finger-tip ; and in so doing feel the size and shape of
the path described by the cane's tip just as immediately as,
without a cane, we should feel the path described by the
tip of our finger. Similarly the draughtsman's immediate
perception seems to be of the point of his pencil, the sur-
* This Is proved by Weber's device of causing the head to be firmly
pressed against a support by another person, whereupon the direction of
traction ceases to be perceived.
86 P8T0H0L007.
geon*s of the end of his knife, the duellist's of the tip of his
rapier as it plunges through his enemy's skin. When on
the middle of a vibrating ladder, we feel not only our feet
on the round, but the ladder's feet against the ground far
below. If we shake a locked iron gate we feel the middle,
on which our hands rest, move, but we equally feel the sta-
bility of the ends where the hinges and the lock are, and
we seem to feel all three at once."'^ And yet the place
where the contact is received is in all these cases the skin,
whose sensations accordingly are sometimes interpreted as
objects on the surface, and at other times as objects a long
distance off.
We shall learn in the chapter on Space that our feelings
of our own movement are principally due to the sensibility
of our rotating joints. Sometimes by fixing the attention,
say on our elbow-joint, we can feel the movement in the
joint itself; but we always are simultaneously conscious
of the path which during the movement our finger-tips
describe through the air, and yet these same finger-tips
themselves are in no way physically modified by the motion.
A blow on our ulnar nerve behind the elbow is felt both
there and in the fingers. Kefrigeration of the elbow pro-
duces pain in the fingers. Electric currents passed through
nerve-trunks, whether of cutaneous or of more special sen-
sibility (such as the optic nerve), give rise to sensations
which are vaguely localized beyond the nerve-tracts
traversed. Persons whose legs or arms have been ampu-
tated are, as is well known, apt to preserve an illusory
feeling of the lost hand or foot being there. Even when
they do not have this feeling constantly, it may be occa-
sionally brought back. This sometimes is the result of
exciting electrically the nerve- trunks buried in the stump
" I recently faradized," says Dr. Mitchell, ** a case of disarticulated
shoulder without warning my patient of the possible result. For two
years he had altogether ceased to feel the limb. As the current affected
the brachial plexus of nerves he suddenly cried aloud, ' Oh the hand,—
the hand I ' and attempted to seize the missing member. The phantom
♦ Lotze: Med. Psych., 438-433; Lipps: Grundtatsachen des Seelenle
682.
SENSATION. 39
I had conjured up swiftly disappeared, but no spirit could have more
amazed the man, so real did it seem." *
Now the apparent position of the lost extremity varies.
Often the foot seems on the ground, or follows the position
of the artificial foot, where one is used. Sometimes where
the arm is lost the elbow will seem bent, and the hand in a
fixed position on the breast. Sometimes, again, the position
is non-natural, and the hand will seem to bud straight out
of the shoulder, or the foot to be on the same level with the
knee of the remaining leg. Sometimes, again, the position
is vague; and sometimes it is ambiguous, as in another
patient of Dr. Weir MitchelFs who
♦'lost his leg at the age of eleven, and remembers that the foot by
degrees approached, and at last reached the knee. When he began to
wear an artificial leg it reassumed in time its old position, and he is
never at present aware of the leg as shortened, unless for some time he
talks and thinks of the stump, and of the missing leg, when . . . the
direction of attention to the part causes a feeling of discomfort, and the
subjective sensation of active and unpleasant movement of the toes.
With these feelings returns at once the delusion of the foot as being
placed at the knee."
All these facts, and others like them, can easily be de-
scribed as if our sensations might be induced by circum-
stances to migrate from their original locality near the brain
or near the surface of the body, and to appear farther off;
and (under different circumstances) to return again after
having migrated. But a little analysis of what happens
shows us that this description is inaccurate.
The objectivity ivith which each of our sensations originally
comes to us, the roomy and spatial character which is a primi-
tive part of its content, is not in the first instance relative to any
other sensation. The first time we open our eyes we get an
optical object which is a place, but which is not yet placed in
relation to any other object, nor identified with any place
otherwise known. It is a place with which so far we are
only oxiquainted. When later we know that this same place
is in * front ' of us, that only means that we have learned
omething about it, namely, that it is congruent with that
* Injuries to Nerves (Philadelphia, 1872), p. 350 ff.
40 P8Y0H0L0QT.
other place, called * front,' which is given us by certain sen-*
sations of the arm and hand or of the head and body. But
at the first moment of our optical experience, even though
we already had an acquaintance with our head, hand, and
body, we could not possibly know anything about their
relations to this new seen object. It could not be immedi-
ately located in respect of them. How its place agrees with
the places which their feelings yield is a matter of which
only later experience can inform us; and in the next
chapter we shall see with some detail how later experience
does this by means of discrimination, association, selection,
and other constantly working functions of the mind. When,
therefore, the baby grasps at the moon, that does not mean
that what he sees fails to give him the sensation which he
afterwards knows as distance ; it means only that he has
not learned at what tactile or maniial distance things which ap-
pear at that visual distance are.^ And when a person just
operated for cataract gropes close to his face for far-off
objects, that only means the same thing. All the ordinary
optical signs of differing distances are absent from the poor
creature's sensation anyhow. His vision is monocular
(only one eye being operated at a time); the lens is gone,
and everything is out of focus; he feels photophobia, lachry-
mation, and other painful resident sensations of the eyeball
itself, whose place he has long since learned to know in
tactile terms ; what wonder, then, that the first tactile reac-
tion which the new sensations provoke should be one
associated with the tactile situation of the organ itself?
And as for his assertions about the matter, what wonder,
again, if, as Prof. Paul Janet says, they are still expressed
in the tactile language which is the only one he knows.
" To be toiujhed means for him to receive an impression with-
out first making a movement." His eye gets such an
impression now ; so he can only say that the objects are
* touching it.'
"All his language, borrowed from touch, but applied to the objects
of his sight, make us think that he perceives differently from ourselves,
* In reality it probably means only a restless movement of desire, which
he might make even after he had become aware of his impotence to touch
the object.
SENSATION. 41
whereas, at bottom, it is only his different way of talking about the same
experience." *
The other cases of translocation of our sensations are
equally easily interpreted without supposing any * projec-
tion ' from a centre at which they are originally perceived.
Unfortunately the details are intricate ; and what I say now
can only be made fully clear when we come to the next
chapter. We shall then see that we are constantly select-
ing certain of our sensations as realities and degrading
others to the status of signs of these. When we get one of
the signs we think of the reality signified ; and the strange
thing is that then the reality (which need not be itself a
sensation at all at the time, but only an idea) is so interest-
ing that it acquires an hallucinatory strength, which may
even eclipse that of the relatively uninteresting sign and en-
tirely divert our attention from the latter. Thus the sen-
sations to which our joints give rise when they rotate are
signs of what, through a large number of other sensations,
tactile and optical, we have come to know as the movement
of the whole limb. This movement of the whole limb is
what we think of when the joint's nerves are excited in that
way ; and its place is so much more important than the
joint's place that our sense of the latter is taken up, so to
speak, into our perception of the former, and the sensation
of the movement seems to diffuse itself into our very fingers
and toes. But by abstracting our attention from the sug-
gestion of the entire extremity we can perfectly well per-
ceive the same sensation as if it were concentrated in one
spot. We can identify it with a differently located tactile
and visual image of * the joint ' itself.
Just so when we feel the tip of our cane against the
ground. The peculiar sort of movement of the hand (im-
possible in one direction, but free in every other) which
we experience when the tip touches * the ground,' is a sign
to us of the visual and tactile object which we already
* Revue Philosophique, vii. p. 1 ff., an admirable critical article, in the
course of which M. Janet gives a bibliography of the cases in question.
See also Dunan: tbid. xxv. 165-7. They are also discussed and similarly
interpreted by T. K. Abbot : Sight and Touch (1864), chapter x.
42 PBTOHOLOOY.
know under that name. We think of ' the ground ' as being
there and giving us the sensation of this kind of movement.
The sensation, we say, comes/row the ground. The ground's
place seems to be its place ; although at the same time,
and for very similar practical reasons, we think of another
optical and tactile object, ' the hand ' namely, and consider
that its place also must be the place of our sensation. In
other words, we take an object or sensible content A, and
confounding it with another object otherwise known, B, or
with two objects otherwise known, B and C, we identify its
place with their places. But in all this there is no ^project-
ing ' (such as the extradition-philosophers talk of) of A out
of an original place; no primitive location which it first
occupied, away from these other sensations, has to be con-
tradicted ; no natural ' centre,' from which it is expelled,
exists. That would imply that A aboriginally came to us
in definite local relations with other sensations, for to be
out of B and C is to be in local relation with them as much
as to be in them is so. But it was no more out of B and C
than it was in them when it first came to us. It simply
had nothing to do with them. To say that we feel a sen-
sation's seat to be * in the brain ' or ' against the eye ' or
' under the skin ' is to say as much about it and to deal
with it in as non-primitive a way as to say that it is a mile
off. These are all secondary perceptions, wa^^s of defining
the sensation's seat per aliud. They involve numberless
associations, identifications, and imaginations, and admit a
great deal of vacillation and uncertainty in the result.*
I conclude, tlwn, that there is no truth in the ' eccentric pro-
jection ' theory. It is due to the confused assumption that
the bodily processes which cause a sensation must also be
its seat, f But sensations have no seat in this sense. They
* The intermediary and shortened locations of the lost hand and foot in
the amputation cases also show this. It is easy to see why the phantom
foot might continue to follow the position of the artificial one. But I
confess that I cannot explain its half way-positions.
f It is from this confused assumption that the time-honored riddle
comes, of how, with an upside-down picture on the retina, we can see
things right-side up. Our consciousness is naively supposed to inhabit the
SENSATION. 43
become seats for each other, as fast as experience associates
them together ; but that violates no primitive seat possessed
by any one of them. And though our sensations cannot
then so analyze and talk of themselves, yet at their very
first appearance quite as much as at any later date are they
cognizant of all those qualities which we end by extracting
and conceiving under the names of objectivity, exteriority,
and extent. It is surely subjectivity and interiority which
are the notions latest acquired by the human mind. *
picture and to feel the picture's position as related to other objects of space.
But the truth is that the picture is non-existent either as a habitat or as any-
thing else, for immediate consciousness. Our notion of it is an enormous-
ly late conception. The outer object is given immediately with all those
qualities which later are named and determined in relation to other sensa-
tions. The ' bottom ' of this object is where we see what by touch we
afterwards know as onxfeet, the ' top ' is the place in which we see what
we know as other people's heads, etc., etc. Berkeley long ago made this
matter perfectly clear (see his Essay towards a new Theory of Vision,
§§ 93-98, 113-118).
* For full justification the reader must see the next chapter. He may
object, against the summary account given now, that in a babe's immediate
field of vision the various things which appear are located relatively to each
other from the outset. I admit that if discriminated, they would appear so
located. But they are parts of the content of one sensation, not sensations
separately experienced, such as the text is concerned with. The fully de-
veloped 'world,' in which all our sensations ultimately find location, is
nothing but an imaginary object framed after the pattern of the field of
vision, by the addition and continuation of one sensation upon another in
an orderly and systematic way. In corroboration of my text I must refer
to pp. 57-60 of Riehl's book quoted above on page 33, and to Uphues :
Wahrnehmung und Empfindung (1888), especially the Mnleitung and
pp. 51-61.
CHAPTEK XVIII.
IMAGINATION.
Sensations, once experienced, modify the nervous organisnit
BO that copies of them arise again in the mind after the orig-
inal outward stimulus is gone. No mental copy, however,
can arise in the mind, of any kind of sensation which has
never been directly excited from without.
The blind may dream of sights, the deaf of sounds,
for years after they have lost their vision or hearing ; * but
the man born deaf can never be made to imagine what sound
is like, nor can the man born blind ever have a mental
vision. In Locke's words, already quoted, " the mind can
frame unto itself no one new simple idea." The originals
of them all must have been given from without. Fantasy, or
ImaginatioQ, are the names given to the faculty of repro-
ducing copies of originals once felt. The imagination is
called * reproductive ' when the copies are literal ; * pro-
ductive ' when elements from different originals are recom-
bined so as to make new wholes.
After-images belong to sensation rather than to imagi-
nation ; so that the most immediate phenomena of imagi-
nation would seem to be those tardier images (due to what
the Germans call Sinnesgeddchtniss) which were spoken of
in Vol. I, p. 647, — coercive hauntings of the mind by echoes
of unusual experiences for hours after the latter have taken
place. The phenomena ordinarily ascribed to imagination,
however, are those mental pictures of possible sensible
* Prof. Jastrow has ascertained by statistical inquiry among the blind
that if their blindness have occurred before a period embraced between the
fifth and seventh years the visual centres seem to decay, and visual dreams
and images are gradually outgrown. If sight is lost after the seventh
year, visual imagination seems to survive through life. See Prof. J. 's in-
teresting article on the Dreams of the Blind, in the New Princeton Review
for January 1888.
44
IMAGINATION. 46
experiences, to which the ordinary processes of associa-
tive thought give rise.
When represented with surroundings concrete enough
to constitute a date, these pictures, when they revive, form
recollections. We have already studied the machinery of
recollection in Chapter XVI. When the mental pictures
are of data freely combined, and reproducing no past com-
bination exactly, we have acts of imagination properly
so called.
OUB IMAGES ABE USUALLY VAGUE.
For the ordinary * analytic ' psychology, each sensibly
discernible element of the object imagined is repre-
sented by its own separate idea, and the total object
is imagined by a ' cluster ' or * gang ' of ideas. We have
seen abundant reason to reject this view (see p. 276 ff.). An
imagined object, however complex, is at any one moment
thought in one idea, which is aware of all its qualities to-
gether. If I slip into the ordinary way of talking, and
speak of various ideas * combining,' the reader will under-
stand that this is only for popularity and convenience, and
he will not construe it into a concession to the atomistic
theory in psychology.
Hume was the hero of the atomistic theory. Not only
were ideas copies of original impressions made on the sense-
organs, but they were, according to him, completely ade-
quate copies, and were all so separate from each other as
to possess no manner of connection. Hume proves ideas
in the imagination to be completely adequate copies, not
by appeal to observation, but by a priori reasoning, as fol-
lows:
"The mind cannot form any notion of quantity or quality, without
forming a precise notion of the degrees of each," for "'tis confessed
that no object can appear to the senses ; or in other words, that no im-
pression* can become present to the mind, without being determined in
its degrees both of quantity and quality. The confusion in which im-
pressions are sometimes involved proceeds only from their faintness
and unsteadiness, not from any capacity in the mind to receive any im-
pression, which in its real existence has no particular degree nor pro-
portion. That is a contradiction in terms; and even implies the flattest
* Impression means sensation for Hume
46 parcHOLooY.
of all contradictions, viz.^ that 'tis possible for the same thing both to
be and not to be. Now since all ideas are derived from impressions,
and are nothing but copies and representations of them, whatever is
true of the one must be acknowledged concerning the other. Impres-
sions and ideas differ only in their strength and vivacity. The forego-
ing conclusion is not founded on any particular degree of vivacity. It
cannot therefore be affected by any variation in that particular. An
idea is a weaker impression ; and as a strong impression must neces-
sarily have a determinate quantity and quality, the case must be the
same with its copy or representative." *
The slightest introspectiye glance will show to anyone
the falsity of this opinion. Hume surely had images of
his own works without seeing distinctly every word and
letter upon the pages which floated before his mind's eye.
His dictum is therefore an exquisite example of the way in
which a man will be blinded by a priori theories to the
most flagrant facts. It is a rather remarkable thing, too,
that the psychologists of Hume's own empiricist school
have, as a rule, been more guilty of this blindness than
their opponents. The fundamental facts of consciousness
have been, on the whole, more accurately reported by the
spiritualistic writers. None of Hume's pupils, so far as I
know, until Taine and Huxley, ever took the pains to con-
tradict the opinion of their master. Prof. Huxley in his
brilliant little work on Hume set the matter straight in the
following words :
** When complex impressions or complex ideas are reproduced as
memories, it is probable that the copies never give all the details of the
originals with perfect accuracy, and it is certain that they rarely do so.
No one possesses a memory so good, that if he has only once observed
a natural object, a second inspection does not show him something that
he has forgotten. Almost all, if not all, our memories are therefore
sketches, rather than portraits, of the originals — the salient features
are obvious, while the subordinate characters are obscure or unrepre-
sented.
"Now, when several complex impressions which are more or less
different from one another— let us say that out of ten impressions in
each, six are the same in all, and four are different from all the rest —
are successively presented to the mind, it is easy to see what must be
the nature of the result. The repetition of the six similar impressions
will strengthen the six corresponding elements of the complex idea,
* Treatise on Human Nature, part i. § vn.
IMAOlNATIOir. 47
which will therefore acquire greater vividness ; while the four differing
impressions of each will not only acquire no greater strength than they
had at first, but, in accordance with the law of association, they wiU
all tend to appear at once, and will thus neutralize one another.
"This mental operation may be rendered comprehensible by consid-
ering what takes place in the formation of compound photographs —
when the images of the faces of six sitters, for example, are each re-
ceived on the same photographic plate, for a sixth of the time requisite
to take one portrait. The final result is that all those points in which
the six faces agree are brought out strongly, while all those in which
they differ are left vague ; and thus what may be termed a generic por-
trait of the six, in contradistinction to a specific portrait of any one, is
produced.
" Thus our ideas of single complex impressions are incomplete in
one way, and those of numerous, more or less similar, complex im-
pressions are incomplete in another way ; that is to say, they are gen-
eric^ not specific. And hence it follows that our ideas of the impres-
sions in question are not, in the strict sense of the word, copies of those
impressions ; while, at the same time, they may exist in the mind in-
dependently of language.
" The generic ideas which are formed from several similar, but not
identical, complex experiences are what are called abstract or general
ideas ; and Berkeley endeavored to prove that all general ideas are
nothing but particular ideas annexed to a certain term, which gives
them a more extensive signification, and makes them recall, upon oc-
casion, other individuals which are similar to them. Hume says that
he regards this as ' one of the greatest and the most valuable discover-
ies that has been made of late years in the republic of letters,' and en-
deavors to confirm it in such a manner that it shall be ' put beyond
all doubt and controversy. '
" I may venture to express a doubt whether he has succeeded in his
object ; but the subject is an abstruse one ; and I must content my-
self with the remark, that though Berkeley's view appears to be largely
applicable to such general ideas as are formed after language has been
acquired, and to all the more abstract sort of conceptions, yet that gen-
eral ideas of sensible objects may nevertheless be produced in the way
indicated, and may exist independently of language. Tn dreams, one
sees houses, trees, and other objects, which are perfectly recognizable as
such, but which remind one of the actual objects as seen ' out of the
corner of the eye,' or of the pictures thrown by a badly-focussed magic
lantern. A man addresses us who is like a figure seen in twilight ; or
we travel through countries where every feature of the scenery is vague ;
the outlines of the hills are ill-marked, and the rivers have no defined
banks. They are, in short, generic ideas of many past impressions of
men, hills, and rivers. An anatomist who occupies himself intently
with the examination of several specimens of some new kind of animal,
in course of time acquires so vivid a conception of its form and struc-
48 P8T0H0L0GT.
ture that the idea may take visible shape and become a sort of waking
dream. But the figure which thus presents itself is generic, not spe-
cific. It is no copy of any one specimen, but, more or less, a mean of
the series ; and there seems no reason to doubt that the minds of chil-
dren before they learn to speak, and of deaf-mutes, are peopled wi*h
similarly generated generic ideas of sensible objects." *
Are Vague Images ' Abstract Ideas ' ?
The only point which I am tempted to criticise in this
account is Prof. Huxley's identification of these generic images
with * abstract or general ideas ' in the sense of universal concep-
tions. Taine gives the truer vie^. He writes :
"Some years ago I saw in England, in Kew Gardens, for the first
time, araucarias, and I walked along the beds looking at these strange
plants, with their rigid bark and compact, short, scaly leaves, of a
sombre green, whose abrupt, rough, bristling form cut in upon the fine
softly-lighted turf of the fresh grass-plat. If I now inquire what this
experience has left in me, I find, first, the sensible representation of an
araucaria ; in fact, I have been able to describe almost exactly the form
and color of the plant. But there is a difference between this represen-
tation and the former sensations, of which it is the present echo. The
internal semblance, from which I have just made my description, is
vague, and my past sensations were precise. For, assuredly, each of
the araucarias I saw then excited in me a distinct visual sensation ;
there are no two absolutely similar plants in nature ; I observed perhaps
twenty or thirty araucarias ; without a doubt each one of them differed
from the others in size, in girth, by the more or less obtuse angles of its
branches, by the more or less abrupt jutting out of its scales, by the style
of its texture ; consequently, my twenty or thirty visual sensations were
different. But no one of these sensations has completely survived in its
echo ; the twenty or thirty revivals have blunted one another ; thus
upset and agglutinated by their resemblance they are confounded
together, and my present representation is their residue only. This is
the product, or rather the fragment, which is deposited in us, when we
have gone through a series of similar facts or individuals. Of our
numerous experiences there remain on the following day four or five
more or less distinct recollections, which, obliterated themselves, leave
behind in us a simple colorless, vague representation, into which enter
as components various reviving sensations, in an utterly feeble, incom-
plete, and abortive state. — But this representation is not the general and
abstract idea. It is but its accompaniment, and, if I may say so, the
ore from which it is extracted. For the representation, though badly
sketched, is a sketch, the sensible sketch of a distinct individual. . . .
But my abstract idea corresponds to the whole class ; it differs, then,
from the representation of an individual. — Moreover, my abstract idea
♦Huxley's Hume, pp. 92-94.
IMAGINATION. 49
is perfectly clear and determinate ; now that I possess it, I never fail
to recognize an araucaria among the various plants whichmay be shown
me ; it differs then from the confused and floating representation I have
of some particular araucaria." *
In other words, a blurred picture is just as much a single
mental fact as a sharp picture is ; and the use of either picture
by the mind to symbolize a whole doss of individuals is a new
mental function, requiring some other modification of con-
sciousness than the mere perception that the picture is
distinct or not. I may bewail the indistinctness of my
mental image of my absent friend. That does not prevent
my thought from meaning him alone, however. Audi may
mean all mankind, with perhaps a very sharp image of one
man in my mind's eye. The meaning is a function of the
more * transitive ' parts of consciousness, the * fringe ' of
relations which we feel surrounding the image, be the latter
sharp or dim. This was explained in a previous place (see
p. 473 ff., especially the note to page 477), and I would not
touch upon the matter at all here but for its historical
interest.
Our ideas or images of past sensible experiences may
then be either distinct and adequate or dim, blurred, and
incomplete. It is likely that the difierent degrees in which
different men are able to make them sharp and complete
has had something to do with keeping up such philosophic
disputes as that of Berkeley with Locke over abstract ideas.
Locke had spoken of our possessing * the general idea of a
triangle ' which " must be neither oblique nor rectangle,
neither equilateral, equicrural, nor scalenon, but all and
none of these at once." Berkeley says :
'' If any man has the faculty of framing in his mind such an idea of
a triangle as is here described, it is in vain to pretend to dispute him
out of it, nor would I go about it. All I desire is that the reader would
fully and certainly inform himself whether he has such an idea or no." f
Until very recent years it was supposed by all philoso-
phers that there was a typical human mind which all indi-
vidual minds were like, and that propositions of universal
validity could be laid down about such faculties as * the
* On Intelligence (N. Y.), vol. ii. p. 139.
t Principles, Introd. ^ 13. Ctompare al»o the passage quoted abor*,
60
PBTCHOLOOT.
Imagination.' Lately, however, a mass of revelations have
poured in, which make us see how false a view this is.
There are imaginations, not *the Imagination,' and they
must be studied in detail.
INDIVIDUALS DIFFER IN IMAGINATION.
The first breaker of ground in this direction was Fechner,
in 1860. Fechner was gifted with unusual talent for sub-
jective observation, and in chapter xuv of his ' Psychophy-
sik' he gave the results of a most careful comparison of his
own optical after-images, with his optical memory-pictures,
together with accounts by several other individuals of their
optical memory-pictures.* The result was to show a great
* The differences noted by Fechner between after-images and images
of imagination proper are as follows :
After-images.
Feel coercive ;
Seem unsubstantial, vaporous
Are sharp in outline ;
Are bright ;
Are almost colorless ;
Are continuously enduring ;
Cannot be voluntarily changed..
Are exact copies of originals.
Are more easily got with shut than
with open eyes ;
Seem to move when the head or eyes
move ;
The field within which they appear
(with closed eyes) is dark, con-
tracted, flat, close to the eyes, in
front, and the images have no
perspective ;
The attention seems directed for-
wards towards the sense-organ, in
observing after-images.
Imaginaiion-irrKiges.
Peel subject to our spontaneity ;
Have, as it were, more body ;
Are blurred ;
Are darker than even the darkest
black of the after-images ;
Have lively coloration ;
Incessantly disappear, and have to
be renewed by an effort of will.
At last even this fails to revive
them.
Can be exchanged at will for others.
Cannot violate the necessary laws of
appearance of their originals — e. g. ,
a man cannot be imagined from
in front and behind at once. The
imagination must walk round him,
so to speak ;
Are more easily had with open than
with shut eyes ;
Need not follow movements of head
or eyes.
The field is extensive in three dimen-
sions, and objects can be imagined
in it above or behind almost as
easily as in front.
In imagining, the attention feels afc
if drawn backwards towards th«
brain.
Finally, Fechner speaks of the impossibility of attending to both after*
I
JMAOINATION. 51
personal diversity. "It would be interesting," he writes,
"to work up the subject statistically; and I regret that
other occupations have kept me from fulfilling my earlier
intention to proceed in this way."
Flechner's intention was independently executed by Mr.
Gallon, the publication of whose results in 1880 may be
said to have made an era in descriptive Psychology.
"It is not necessary,' says Gal ton, " to trouble the reader with my
early tentative steps. After the inquiry had been fairly started it took
the form of submitting a certain number of printed questions to a large
number of persons. There is hardly any more difficult task than that
of framing questions which are not likely to be misunderstood, which
admit of easy reply, and which cover the ground of inquiry. I did my
best in these respects, without forgetting the most important part of
all — namely, to tempt my correspondents to write freely in fuller ex-
planation of their replies, and on cognate topics as well. These sepa-
rate letters have proved more instructive and interesting by far than the
replies to the set questions.
" The first group of the rathei long series of queries related to the
illumination, definition, and violoring of the mental image, and were
framed thus :
" ' Before addressing yourself to any of the Questions on the opposite
page, think of some definite object — suppose it is your breakfast-table
as you sat down to it this morning — and consider carefully the picture
that rises before your mind's eye.
' " 1. Illumination. — Is the image dim or fairly clear ? Is its bright-
ness comparable to that of the actual scene ?
" ' 2. Definition. — Are all the objects pretty well defined at the same
time, or is the place of sharpest definition at any one moment more con-
tracted than it is in a real scene ?
'* ' 3. Coloring. — Are the colors of the china, of the toast, bread-crust,
mustard, meat, parsley, or whatever may have been on the table, quite
distinct and natural ? '
" The earliest results of my inquiry amazed me. I had begun by
questioning friends in the scientific world, as they were the most likely
class of men to give accurate answers concerning this faculty of visual-
images and imagination-images at once, even when they are of the same
object and might be expected to combine. All these differences are true
of Fechner; but many of them would be untrue of other persons, I quote
them as a type of observation which any reader with sufficient patience
may repeat. To them may be added, as a universal proposition, that after-
images seem larger if we project them on a distant screen, and smaller if
we project them on a near one, whilst no such change takes place in men-
tal pictures.
62 PBTCHOLOOT
iiing, to which noTelists and poets continually allude, which has left
an abiding mark on the vocabularies of every language, and which
supplies the material out of which dreams and the well-known halluci-
nations of sick people are built.
"To my astonishment, I found that the great 7naJority of the men
of science to whom I first applied protested that mental imagery was
unknown to them, and they looked on me as fanciful and fantastic in
supposing that the words ' mental imagery ' really expressed what 1
believed everybody supposed them to mean. They had no more notion
of its true nature than a color-blind man, who has not discerned his
defect, has of the nature of color. They had a mental deficiency of
which they were unaware, and naturally enough supposed that those
who affirmed they possessed it were romancing. To illustrate their
mental attitude it will be sufficient to quote a few lines from the letter
of one of my correspondents, who writes :
*' ' These questions presuppose assent to some sort of a proposition re-
garding the "mind's eye," and the "images" which it sees. . . . This
points to some initial fallacy. ... It is only by a figure of speech that
1 can describe my recollection of a scene as a " mental image " which
I can " see " with my " mind's eye. " . . . I do not see it . . . anymore
than a man sees the thousand lines of Sophocles which under due
pressure he is ready to repeat. The memory possesses it,' etc.
" Much the same result followed inquiries made for me by a friend
among members of the French Institute.
" On the other hand, when I spoke to persons whom I met in gen-
eral society, I found an entirely different disposition to prevail. Many
men and a yet larger number of women, and many hoys and girls,
declared that they habitually saw mental imagery, and that it was
perfectly distinct to them and full of color. The more I pressed and
crossed-questioned them, professing myself to be incredulous, the more
obvious was the truth of their first assertions. They described
their imagery in minute detail, and they spoke in a tone of surprise at
my apparent hesitation in accepting what they said. I felt that I my-
self should have spoken exactly as they did if I had been describing a
scene that lay before my eyes, in broad daylight, to a blina man who
persisted in doubting the reality of vision. Keassured by this happier
experience, I recommenced to inquire among scientific men, and soon
found scattered instances of what I sought, though in by no means the
same abundance as elsewhere. I then circulated my questions more
generally among my friends and through their hands, and obtained re-
plies . . . from persons of both sexes, and of various ages, and in the
end from occasional correspondents in nearly every civilized country.
*' I have also received batches of answers from various educational
establishments both in England and America, which were made after
the masters had fully explained the meaning of the questions, and in-
terested the boys in them. These have the merit of returns derived
from a general census, which my other data lack, because I cannot for
IMAGINATION, 68
a moment suppose that the writers of the latter are a haphazard pro-
portion of those to whom they were sent. Indeed I know of some who,
disavowing all possession of the power, and of many others who, pos-
sessing it in too faint a degree to enable them to express what their
experiences really were, in a manner satisfactory to themselves, sent no
returns at all. Considerable statistical similarity was, however, ob-
served between the sets of returns furnished by the schoolboys and
those sent by my separate correspondents, and I may add that they ac-
cord in this respect with the oral information I have elsewhere obtained.
The conformity of replies from so many different sources which was
clear from the first, the fact of their apparent trustworthiness being on
the whole much increased by cross-examination (though I could give
one or two amusing instances of break-down), and the evident effort
made to give accurate answers, have convinced me that it is a much
easier matter than I had anticipated to obtain trustworthy replies to
psychological questions. Many persons, especially women and intelli-
gent children, take pleasure in introspection, and strive their very best
to explain their mental processes. I think that a delight in self-disseo-
tion must be a strong ingredient in the pleasure that many are said to
take in confessing themselves to priests.
*' Here, then, are two rather notable results : the one is the proved
facility of obtaining statistical insight into the processes of other per-
sons' minds, whatever a priori objection may have been made as to its
possibility ; and the other is that scientific men, as a class, have feeble
powers of visual representation. There is no doubt whatever on the
latter point, however it may be accounted for. My own conclusion is
that an over-ready perception of sharp mental pictures is antagonistic
to the acquirement of habits of highly-generalized and abstract thought,
especially when the steps of reasoning are carried on by words as
symbols, and that if the faculty of seeing the pictures was ever possessed
by men who think hard, it is very apt to be lost by disuse. The highest
minds are probably those in which it is not lost, but subordinated, and
is ready for use on suitable occasions. I am, however, bound to say
that the missing faculty seems to be replaced so serviceably by other
modes of conception, chiefly, I believe, connected with the incipient
motor sense, not of the eyeballs only but of the muscles generally, thai
men who declare themselves entirely deficient in the power of seeing
mental pictures can nevertheless give lifelike descriptions of what they
have seen, and can otherwise express themselves as if they were gifted
with a vivid visual imagination. They can also become painters of the
rank of Eoyal Academicians.'^ . . .
* [I am myself a good draughtsman, and have a very lively interest in
pictures, statues, architecture and decoration, and a keen sensibUity to
artistic effects. But I am an extremely poor visualizer, and find myself
often unable to reproduce in my mind's eye pictures which I have most
carefully examined. — W. J.]
54 PBTOBOLOGT.
**It ig a mistake to suppose that sharp sight is accompanied by clear
yisual memory. I have not a few instances in which the independence
of the two faculties is emphatically commented on ; and I have at least
one clear case where great interest in outlines and accurate appreciation
of straightness, squareness, and tho like, is unaccompanied by the
power of visualizing. Neither does the faculty go with dreaming. I
have cases where it is powerful, and at the same time where dreams
are rare and faint or altogether absent. One friend tells me that his
dreams have not the hundredth part of the vigor of his waking fancies.
" The visualizing and the identifying powers are by no means nec-
essarily combined. A distinguished writer on metaphysical topics as-
sures me that he is exceptionally quick at recognizing a face that he
has seen before, but that he cannot call up a mental image of any face
With clearness.
** Some persons have the power of combining in a single perception
more than can be seen at any one moment by the two eyes. . . .
"I find that a few persons can, by what they often describe as a
kind of touch -sight, visualize at the same moment all round the image
of a solid body. Many can do so nearly, but not altogether round that
of a terrestrial globe. An eminent mineralogist assures me that he is
able to imagine simultaneously all the sides of a crystal with which he
is familiar. I may be allowed to quote a curious faculty of my own in
respect to this. It is exercised only occasionally and in dreams, or
rather in nightmares, but under those circumstances I am perfectly
conscious of embracing an entire sphere in a single perception. It ap-
pears to lie within my mental eyeball, and to be viewed centripetally.
"This power of comprehension is practically attained in many cases
by indirect methods. It is a common feat to take in the whole sur-
roundings of an imagined room with such a rapid mental sweep as to
leave some doubt whether it has not been viewed simultaneously. Some
persons have the habit of viewing objects as though they were partly
transparent ; thus, if they so dispose a globe in their imagination as to
see both its north and south poles at the same time, they will not be
able to see its equatorial parts. They can also perceive all the rooms of
an imaginary house by a single mental glance, the walls and floors being
as if made of glass. A fourth class of persons have the habit of recall-
ing scenes, not from the point of view whence they were observed, but
from a distance, and they visualize their own selves as actors on the
mental stage. By one or other of these ways, the power of seeing the
whole of an object, and not merely one aspect of it, is possessed by
many persons.
**The place where the image appears to lie differs much. Most per-
sons see it in an indefinable sort of way, others see it in front of the eye,
others at a distance corresponding to reality. There exists a power
which is rare naturally, but can, I believe, be acquired without much
difficulty, of projecting a mental picture upon a piece of paper, and of
IMAGINATION. 55
holding it fast there, so that it can be outlined with a pencil. To this
I shall recur.
"Images usually do not become stronger by dwelling on them; the
first idea is commonly the most vigorous, but this is not always the case.
Sometimes the mental view of a locality is inseparably connected with
the sense of its position as regards the points of the compass, real or
imaginary. I have received full and curious descriptions from very
different sources of this strong geographical tendency, and in one or
two cases I have reason to think it allied to a considerable faculty of
geographical comprehension.
" The power of visualizing is higher in the female sex than in the male,
and is somewhat, but not much, higher in public-school boys than in
men. After maturity is reached, the further advance of age does not
seem to dim the faculty, but rather the reverse, judging from numerous
statements to that effect; but advancing years are sometimes accom-
panied by a growing habit of hard abstract thinking, and in these cases
— not uncommon among those whom I have questioned — the faculty
undoubtedly becomes impaired. There is reason to believe that it is very
high in some young children, who seem to spend years of difficulty in
distinguishing between the subjective and objective world. Language
and book-learning certainly tend to dull it.
"The visualizing faculty is a natural gift, and, like all natural gifts,
has a tendency to be inherited. In this faculty the tendency to inheri-
tance is exceptionally strong, as I have abundant evidence to prove,
especially in respect to certain rather rare peculiarities, . . . which,
when they exist at all, are usually found among two, three, or more
brothers and sisters, parents, children, uncles and aunts, and cousins.
" Since families differ so much in respect to this gift, we may suppose
that races would also differ, and there can be no doubt that such is the
case. I hardly like to refer to civilized nations, because their natural
faculties are too much modified by education to allow of their being
appraised in an off-hand fashion. I may, however, speak of the French,
who appear to possess the visualizing faculty in a high degree. The
peculiar ability they show in prearranging ceremonials and fetes of all
kinds, and their undoubted genius for tactics and strategy, show that
they are able to foresee effects with unusual clearness. Their ingenuity
in all technical contrivances is an additional testimony in the same direc-
tion, and so is their singular clearness of expression. Their phrase
' figurez-vous,' or ' picture to yourself,' seems to express their dominant
mode of perception. Our equivalent of ' imagine ' is ambiguous.
"I have many cases of persons mentally reading off scores when
playing the pianoforte, or manuscript when they are making speeches.
One statesman has assured me that a certain hesitation in utterance
which he has at times is due to his being plagued by the image of his
06 P8T0H0L0OY.
manuscript spoech with its original erasures and corrections. He oim-
not lay the ghost, and he puzzles in trying to decipher it.
** Some few persons see mentally in print every word that is uttered;
they attend to the visual equivalent and not to the sound of the words,
and they read them off usually as from a long imaginary strip of paper,
•uch as is unwound from telegraphic instruments."
The reader will find further details in Mr. Galton's
'Inquiries into Human Faculty,' pp. 83-114* I have
myself for many years collected from each and all of my
psychology-students descriptions of their own visual
imagination ; and found (together with some curious idio-
syncrasies) corroboration of all the variations which Mr.
Galton reports. As examples, I subjoin extracts from two
oases near the ends of the scale. The writers are first cous-
ins, grandsons of a distinguished man of science. The one
who is a good visualizer says :
" This morning's breakfast-table is both dim and bright; it is dim if
I try to think of it when my eyes are open upon any object; it is per-
fectly clear and bright if I think of it with my eyes closed. —All the
objects are clear at once, yet when I confine my attention to any one
object it becomes far more distinct. — I have more power to recall color
than any other one thing: if, for example, I were to recall a plate deco-
rated with flowers I could reproduce in a drawing the exact tone, etc.
The color of anything that was on the table is perfectly vivid. — There
is very little limitation to the extent of my images: I can see all four
sides of a room, I can see all four sides of two, three, four, even more
rooms with such distinctness that if you should ask me what was in any
particular plaxje in any one, or ask me to count the chairs, etc., I could
do it without the least hesitation. — The more I learn by heart the more
clearly do I see images of my pages. Even before I can recite the lines
I see them so that I could give them very slowly word for word, but
my mind is so occupied in looking at my printed image that I have no
idea of what I am saying, of the sense of it, etc. When I first found
myself doing this I used to think it was merely because I knew the lines
imperfectly; but I have quite convinced myself that I really do see an
image. The strongest proof that such is really the fact is, I think, the
following:
"I can look down the mentally seen page and see the words that
eommenoe all the lines, and from any one of these words I can continue
* See also McCosh and Osborne, Princeton Review, Jan. 1884. There
are some good examples of high development of the Faculty in the London
l^)ectator, Dec. 28, 1878, pp. 1631, 1634, Jan. 4, 11, 25, and March 18, 1879.
IMAGINATION. 67
the line. I find this much easier to do if the words begin in a straight
line i^han if there are breaks. Example :
Mantfait
Tms
A des
Que fit
Cires .....
Avec
TJnfleur
Comme
{La Fontaine 8. iv.)"
The poor visualizer says :
*' My ability to form mental images seems, from what I have studiea
of other people's images, to be defective, and somewhat peculiar. The
process by which I seem to remember any particular event is not by a
series of distinct images, but a sort of panorama, the faintest impres-
sions of which are perceptible through a thick fog. — I cannot shut my
eyes and get a distinct image of anyone, although I used to be able to a
few years ago, and the faculty seems to have gradually slipped away.
—In my most vivid dreams, where the events appear like the most real
facts, I am often troubled with a dimness of sight which causes the
images to appear indistinct.— To come to the question of the breakfast-
table there is nothing definite about it. Everything is vague. I can-
not say what I see. I could not possibly count the chairs, but I happen
to know that there are ten. I see nothing in detail. — The chief thing is a
general impression that I cannot tell exactly what I do see. The color-
ing is about the same, as far as I can recall it, only very much washed
out. Perhaps the only color I can see at all distinctly is that of the table-
cloth, and I could probably see the color of the wall-paper if I could
remember what color it was."
A person whose visual imagination is strong finds it
hard to understand how those who are without the faculty
can think at all. Some people undoubtedly have no visuod
images at all worthy of the name,"^ and instead of seeing their
breakfast-table, they tell you that they remember it or knx)w
what was on it. This knowing and remembering takes
* Take the following report from one of my students : "I am unable
to form in my mind's eye any visual likeness of the table whatever. After
many trials, I can only get a. hazy surface, with nothing on it or about it.
1 can see no variety in color, and no positive limitations in extent, while I
cannot see what I see well enough to determine its position in respect to
my eye, or to endow it with any quality of size. I am in the same position
as to the word dog. I cannot see it in my mind's eye at all ; and so cannot
t«ll whether I should have to run my eye along it, if I did see it."
58 PSYCHOLOGY.
place undoubtedly by means of verbal images, as was ex-
plained already in Chapter IX, pp. 265-6.
The study qf Aphasia (see p. 54) has of late years shovm
how unexpectedly great are the differences between individuals in
respect of imagination. And at the same time the discrepan-
cies between lesion and symptom in different cases of
the disease have been largely cleared up. In some indi-
viduals the habitual * thought-stuff,' if one may so call it,
is visual ; in others it is auditory, articulatory, or motor ;
in most, perhaps, it is evenly mixed. The same local cerebral
injury must needs work different practical results in per-
sons who differ in this way. In one it will throw a much-
used brain-tract out of gear ; in the other it may affect an
unimportant region. A particularly instructive case was
published by Charcot in 1883.^ The patient was
Mr. X., a merchant, born in Vienna, highly educated, master of
German, Spanish, French, Greek, and Latin. Up to the beginning of
the malady which took him to Professor Charcot, he read Homer at
sight. He could, starting from any verse out of the first book of the
Hiad, repeat the following verses without hesitating, by heart. Virgil
and Horace were familiar. He also knew enough of modern Greek for
business purposes. Up to within a year (from the time Charcot saw
him) he enjoyed an exceptional visual memory. He no sooner thought
of persons or things, but features, forms, and colors arose with the
same clearness, sharpness, and accuracy as if the objects stood before
him. When he tried to recall a fact or a figure in his voluminous
polyglot correspondence, the letters themselves appeared before him
with their entire content, irregularities, erasures and all. At school he
recited from a mentally seen page which he read off line by line and
letter by letter. In making computations, he ran his mental eye down
imaginary columns of figures, and performed in this way the most
varied operations of arithmetic. He could never think of a passage in
a play without the entire scene, stage, actors, and audience appearing
to him. He had been a great traveller. Being a good draughtsman,
he used to sketch views which pleased him; and his memory always
brought back the entire landscape exactly. If he thought of a conver-
sation, a saying, an engagement, the place, the people, the entire scene
rose before his mind.
His auditory memory was always deficient, or at least secondary
He had no taste for music.
* Progrds Medical, 21 juillet. I abridge from the German report of
the case in Wilbrand : Die tSeelenblindheit (1887>
IMAGINATION, 59
A year and a half previous to examination, after business-anxieties,
loss of sleep, appetite, etc. , he noticed suddenly one day an extraordi-
nary change in himself. After complete confusion, there came a violent
contrast between his old and his new state. Everything about him
seemed so new and foreign that at first he thought he must be going
mad. He was nervous and irritable. Although he saw all things dis-
tinct, he had entirely lost his memory for forms and colors. On ascer-
taining this, he became reassured as to his sanity. He soon discovered
that he could carry on his affairs by using his memory in an altogether
new way. He can now describe clearly the difference between his two
conditions.
Every time he returns to A., from which place business often calls
him, he seems to himself as if entering a strange city. He views the
monuments, houses, and streets with the same surprise as if he saw
them for the first time. Gradually, however, his memory returns, and
he finds himself at home again. When asked to describe the principal
public place of the town, he answ^ered, " I know that it is there, but it
is impossible to imagine it, and I can tell you nothing about it. " He has
often drawn the port of A. To-day he vainly tries to trace its principal
outlines. Asked to draw a minaret, he reflects, says it is a square
tower, and draws, rudely, four lines, one for ground, one for top, and
two for sides. Asked to draw an arcade, he says, " I remember that it
contains semi-circular arches, and that two of them meeting at an angle
make a vault, but how it looks I am absolutely unable to imagine." The
profile of a man which he drew by request was as if drawn by a little
child; and yet he confessed that he had been helped to draw it by look-
ing at the bystanders. Similarly he drew a shapeless scribble for a
tree.
He can no more remember his wife's and children's faces than he
can remember the port of A. Even after being with them some time
they seem unusual to him. He forgets his own face, and once spoke
to his image in a mirror, taking it for a stranger. He complains of his
loss of feeling for colors. " My wife has black hair, this I know; but
I can no more recall its color than I can her person and features."
This visual amnesia extends to dating objects from his childhood's
years — paternal mansion, etc., forgotten.
No other disturbances but this loss of visual images. Now when he
seeks something in his correspondence, he must rummage among the
letters like other men, until he meets the passage. He can recall only
the first few verses of the Iliad, and must grope to read Homer, Virgil,
and Horace. Figures which he adds he must now whisper to himself.
He realizes clearly that he must help his memory out with auditory
images, which he does with effort. The words and expressions which
he recalls seem now to echo in his ear, an altogether novel sensation for
him. If he wishes to learn by heart anything, a series of phrases for
example, he must read them, several times aloud, so as to impress his
ear. "When later he repeats the thing in question, the sensation of ia»
60 P8T0H0L0GT.
ward hearing which precedes articulation rises up in his mind. This
feeling was formerly unknown to him. He speaks French fluently; but
affirms that he can no longer think in French; but must get his French
words by translating them from Spanish or German, the languages of
his childhood. He dreams no more in visual terms, but only in words,
usually Spanish words. A certain degree of verbal blindness affects
him— he is troubled by the Greek alphabet, etc.*
If this patient had possessed the auditory type of imag-
ination from the start, it is evident that the injury, what-
ever it was, to his centres for optical imagination, would
have affected his practical life much less profoundly.
** The auditory type^'''' says M. A. Binet,f " appears to he rarer than
the 'visual. Persons of this type imagine what they think of in the
language of sound. In order to remember a lesson they impress upon
their mind, not the look of the page, but the sound of the words.
They reason, as well as remember, by ear. In performing a mental ad-
dition they repeat verbally the names of the figures, and add, as it
were, the sounds, without any thought of the graphic signs. Imag-
ination also takes the auditory form. *When I write a scene,' said
Legouve to Scribe, ' I hear ; but you see. In each phrase which I write,
the voice of tiie personage who speaks strikes my ear. Vous^ qui etes U
theatre meme, your actors walk, gesticulate before your eyes ; I am a
listener^ you a spectator.^ — ' ITothing more true,' said Scribe ; ' do you
know where I am when I write a piece ? In the middle of the parterre.'
It is clear that the pure audile, seeking to develop only a single one of
his faculties, may, like the pure visualizer, perform astounding feats
of memory — Mozart, for example, noting from memory the Miserere of
the Sistine Chapel after two hearings ; the deaf Beethoven, composing
and inwardly repeating his enormous symphonies. On the other hand,
the man of auditory type, like the visual, is exposed to serious dangers ;
for if he lose his auditory images, he is without resource and breaks
down completely.
" It is possible that persons with hallucinations of hearing, and in-
* In a letter to Charcot this interesting patient adds that his character
also is changed : "I was formerly receptive, easily made enthusiastic, and
possessed a rich fancy. Now I am quiet and cold, and fancy never carries
my thoughts away. » . . 1 am much less susceptible than formerly tx)
anger %t sorrow. I lately lost my dearly-beloved mother; but felt far less
grief at the bereavement than if I had been able to see in my mind's eye
her physiognomy and the phases of her suffering, and especially less than
if I had been able to witness in imagination the outward effects of her un-
timely loss upon the members of the family. "
i Psychologic du Raisonnement (1886), p. 25.
IMAGINATION. «1
dividuals afflicted with the mania that they are victims of persecution,
may all belong to the auditory type ; and that the predominance of a
certain kind of imagination may predispose to a certain order of hal-
lucinations, and perhaps of delirium.
'The moto7' type remains — perhaps the most Interesting of all,
and certainly the one of which least is known. Persons who belong to
this type [les moteurs^ in French, motiles, as Mr. Galton proposes to
call them in English] make use, in memory, reasoning, and all their
intellectual operations, of images derived from movement. In order to
understand this important point, it is enough to remember that 'all
our perceptions, and in particular the important ones, those of sight
and touch, contain as integral elements the movements of our eyes and
limbs ; and that, if movement is ever an essential factor in our really
seeing an object, it must be an equally essential factor when we see the
same object in imagination ' (Ribot).* For example, the complex im-
pression of a ball, which is there, in our hand, is the resultant of optical
impressions of touch, of muscular adjustments of the eye, of the move-
ments of our fingers, and of the muscular sensations which these yield.
When we imagine the ball, its idea must include the images of these
muscular sensations, just as it includes those of the retinal and epider-
mal sensations. They form so many motor images. If they were not
earlier recognized to exist, that is because our knowledge of the muscu-
lar sense is relatively so recent. In older psychologies it never was
mentioned, the number of senses being restricted to five.
" There are persons who remember a drawing better when they have
followed its outlines with their finger. Lecoq de Boisbaudran used this
means in his artistic teaching, in order to accustom his pupils to draw
from memory. He made them follow the outlines of figures with a
pencil held in the air, forcing them thus to associate muscular with
visual memory. Galton quotes a curious corroborative fact. Colonel
Moncrieff often observed in North America young Indians who, visit-
ing occasionally his quarters, interested themselves greatly in the
engravings which were shown them. One of them followed with care
with the point of his knife the outline of a drawing in the Illustrated
London News, saying that this was to enable him to carve it out the
better on his return home. In this case the motor images were to
* [I am myself a very poor visualizer, and find that I can seldom call to
mind even a single letter of the alphabet in purely retinal terms. I must
trace the letter by running my mental eye over its contour in order that
the image of it shall have any distinctness at all. On questioning a large
number of other people, mostly students, I find that perhaps half of them
say they have no such difficulty in seeing letters mentally. Many affirm
that they can see an entire word at once, especially a short one like ' dog,'
with no such feeling of creating the letters successively by tracing them
With the eye.— W. J J
(J9 PSTCHOLOOT
reinforce the visual ones. The young savage was a motor. "^ . . . When
one's motor images are destroyed, one loses one's remembrance of move-
ments, and sometimes, more curiously still, one loses the power of exe-
cuting them. Pathology gives us examples in motor aphasia, agraphia,
etc. Take the case of agraphia. An educated man, knowing how to
write, suddenly loses this power, as a result of cerebral injury. His
hand and arm are in no way paralytic, yet he caimot write. Whence
this loss of power ? He tells us himself : he no longer knows how. He
has forgotten how to set about it to trace the letters, he has lost the
memory of the movements to be executed, he has no longer the motor
images which, when formerly he wrote, directed his hand. . . . Other
patients, affected with word-blindness, resort to these motor images
precisely to make amends for their other deficiency. . . . An individ-
ual affected in this way cannot read letters which are placed before his
eyes, even although his sight be good enough for the purpose. This loss
of the power of reading by sight may, at a certain time, be the only
trouble the patient has. Individuals thus mutilated succeed in reading
by an ingenious roundabout way which they often discover themselves :
it is enough that they should trace the letters with their finger to under-
stand their sense. What happens in such a case ? How can the hand
supply the place of the eye ? The motor image gives the key to the
problem. If the patient can read, so to speak, with his fingers, it is
because in tracing the letters he gives himself a certain number of mus-
cular impressions which are those of writing. In one word, the patient
reads by writing (Charcot): the feeling of the graphic movements sug-
gests the sense of what is being written as well as sight w^ould."f
The imagination of a blind-deaf mute like Laura Bridg-
man must be confined entirely to tactile and motor material.
All Uivd persons must belong to the * tactile ' and * motile^ types of
the French authors. When the young man whose cataracts
were removed by Dr. Franz was shown different geometric
figures, he said he " had not been able to form from them
the idea of a square and a disk until he perceived a sensa-
tion of what he saw in the points of his fingers, as if he
really touched the objects." %
Professor Strieker of Vienna, who seems to have the
motile form of imagination developed in unusual strength,
* It is hardly needful to say that in modern primary education, in which
the blackboard is so much used, the children are taught their letters, etc.,
by all possible channels at once, sight, hearing, and movement.
f See an interesting case of a similar sort, reported by Farges, in TEd
c^phale, 7me An nee, p. 545.
X Philosophical Transactions, 1841, p. 66.
IMAOmATION, 68
has given a very careful analysis of "his own case in a
couple of monographs with which all students should be-
come familiar.* His recollections both of his own move-
ments and of those of other things are accompanied
invariably by distinct muscular feelings in those parts of
his body which would naturally be used in effecting or in
following the movement. In thinking of a soldier march-
ing, for example, it is as if he were helping the image to
march by marching himself in his rear. And if he sup-
presses this sympathetic feeling in his own legs, and con-
centrates all his attention on the imagined soldier, the latter
becomes, as it were, paralyzed. In general his imagined
movements, of whatsoever objects, seem paralyzed the
moment no feelings of movement either in his own eyes or
in his own limbs accompany them.f The movements of
articulate speech play a predominant part in his mental
life.
"When after my experimental work I proceed to its description,
as a rule I reproduce in the first instance only words, which I had
already associated with the perception of the various details of the ob-
servation whilst the latter was going on. For speech plays in all my
observing so important a part that I ordinarily clothe phenomena in
words as fast as I observe them." X
Most persons, on being asked in what sort of terms they
imagine words, will say * in terms of hearing.' It is not until
their attention is expressly drawn to the point that they
find it difficult to say whether auditory images or motor
images connected with the organs of articulation predomi-
nate. A good way of bringing the difficulty to consciousness
is that proposed by Strieker : Partly open your mouth and
then imagine any word with labials or dentals in it, such as
* bubble,' * toddle.' Is your image under these conditions
distinct ? To most people the image is at first * thick,' as
the sound of the word would be if they tried to pronounce
it with the lips parted. Many can never imagine the words
* Studien aber die Sprachvorstellungen (1880), and Studien tiber die
Bewegungsvorstellungen (1882).
f Prof. Strieker admits that by practice he has succeeded in making
bis eye-movements ' act vicariously ' for his leg-movements in imagining
men walking.
X Bewegungsvorstellungen, p. 6.
M paroHOLOOT.
clearly with the mouth open ; others succeed after a few
preliminary trials. The experiment proves how dependent
our verbal imagination is on actual feelings in lips, tongue»
throat, larynx, etc.
"When we recall the impression of a word or sentence, if we do not
speak it out, we feel the twitter of the organs just about to come to
that po'.nt. The articulating parts— the larynx, the tongue, the lips—
are all sensibly excited ; a suppressed articulation is in fact the mate-
rial of our recollection, the intellectual manifestation, the idea of
speech. "*
The open mouth in Strieker's experiment not only pre-
vents actual articulation of the labials, but our feeling of
its openness keeps us from imagining their articulation,
just as a sensation of glaring light will keep us from
strongly imagining darkness. In persons whose auditory
imagination is weak, the articulatory image seems to con-
stitute the whole material for verbal thought. Professor
Strieker says that in his own case no auditory image enters
into the words of which he thinks, f Like most psycholo-
gists, however, he makes of his personal peculiarities a rule,
and says that verbal thinking is normally and univer-
sally an exclusively motor representation. I certainly get
auditory images, both of vowels and of consonants, in
addition to the articulatory images or feelings on which
this author lays such stress. And I find that numbers of
my students, after repeating his experiments, come to this
conclusion. There is at first a difficulty due to the open
mouth. That, however, soon vanishes, as does also the
difficulty of thinking of one vowel whilst continuously
sounding another. What probably remains true, however,
is that most men have a less auditory and a more articu-
latory verbal imagination than they are apt to be aware of.
'* Bala : Senses and Intellect, p. 339.
t Studien iiber Sprachvorstellungen, 28, 31, etc. Cf. pp. 49-50, etc.
Against Strieker, see Sturapf, Tonpsychol, 155-162, and Revue Phi-
losophique, xx. 617. See also Pauihan, Rev. Philosophique, xvi. 405
Strieker replies to Pauihan in vol. xviii. p. 685. P. retorts in vol. xix
p. 118. Strieker reports that out of 100 persons questioned he found onlj
one who had no feeling in his lips when silently thinking the letters M B,
P; and out of 60 only two who were conscious of no internal articulation
whilst reading (pp 59-60).
IMAGINATION, 66
Professor Strieker himself has acoustic images, and can
imagine the sounds of musical instruments, and the pecul-
iar voice of a friend. A statistical inquiry on a large scale,
into the variations of acoustic, tactile, and motor iiijagina-
tion, would probably bear less fruit than Galton's inquiry
into visual images. A few monographs by competent ob-
servers, like Strieker, about their own peculiarities, would
give much more valuable information about the diversities
which prevail.*
Tomh'images are very strong in some people. The most
vivid touch-images come when we ourselves barely escape
local injury, or when we see another injured. The place
* I think it must be admitted that some people have no vivid substan-
tive images in any department of their sensibility. One of my students,
an intelligent youth, denied so pertinaciously that there was anything in his
mind at alt when he thought, that I was much perplexed by his case. I my-
self certainly have no such vivid play of nascent movements or motor images
as Professor Strieker describes. When I seek to represent a row of soldiers
marching, all I catch is a view of stationary legs first in one phase of
movement and then in another, and these views are extremely imperfect
and momentary. Occasionally (especially when I try to stimulate my
imagination, as by repeating Victor Hugo's lines about the regiment,
" Leur pas est si correct, sans tarder ni courir,
Qu'on croit voir des ciseaux se farmer et s^ouvrir,")
I seem to get an instantaneous glimpse of an actual movement, but it is to
the last degree dim and uncertain. All these images seem at first as if
purely retinal. I think, however, that rapid eye-movements accompany
them, though these latter give rise to such slight feelings that they are
almost impossible of detection. Absolutely no leg-movements of my own
are there ; in fact, to call such up arrests my imagination of the soldiers.
My optical images are in general very dim, dark, fugitive, and contracted.
It would be utterly impossible to draw from them, and yet I perfectly well
distinguish one from the other. My auditory images are excessively inade-
quate reproductions of their originals. I have no images of taste or smell.
Touch-imagination is fairly distinct, but comes very little into play with
most objects thought of. Neither is all my thought verbalized; for I have
shadowy schemes of relation, as apt to terminate in a nod of the head or an
expulsion of the breath as in a definite word. On the whole, vague images
or sensations of movement inside of my head towards the various parts of
space in which the terms I am thinking of either lie or are momentarily sym-
bolized to lie together with movements of the breath through my pharynx
and nostrils, form a by no means inconsiderable part of my thought-stuff.
I doubt whether my difficulty in giving a clearer account is wholly a mat-
ter of inferior power of introspective attention, though that doubtless plays
its part. Attention, ceteris pa^ibtts, must always be inferior in proportion
lo the feebleness of the internal images which are offered it to bold on to.
66 psYcnoLoor,
may then actually tingle with the imaginary sensation —
perhaps not altogether imaginary, since goose-flesh, pal-
ing or reddening, and other evidences of actual muscular
contraction in the spot may result.
" An educated man," says a writer who must always be quoted when
it is question of the powers of imagination,* "told me once that on
entering his house one day he received a shock from crushing the finger
of one of his little children in the door. At the moment of his fright
he felt a violent pain in the corresponding finger of his own body,
und this pain abode with him three days."
The same author makes the following discrimination,
wiiich probably most men could verify :
" On the skin I easily succeed in bringing out suggested sensationfc
wherever I will. But because it is necessary to protract the mental ef-
fort I can only awaken such sensations as are in their nature prolonged,
as warmth, cold, pressure. Fleeting sensations, as those of a prick, a
cut, a blow, etc., I am unable to call up, because I cannot imagine them
ex ahrupto with the requisite intensity. The sensations of the former
order I can excite upon any part of the skin ; and they may become so
lively that, whether I will or not, I have to pass my hand over the place
just as if it were a real impression on the skin." f
Meyer's account of his own visual images is very interest-
ing ; and with it we may close our survey of differences be-
tween the normal powers of imagining in different indi-
viduals*
"With much practice," he says, " I have succeeded in making it
possible for me to call up subjective visual sensations at will. I tried
all my experiments by day or at night with closed eyes. At first it
was very difficult. In the first experiments which succeeded the whole
picture was luminous, the shadows being given in a somewhat less strong
bluish light. In later experiments I saw the objects dark, with
bright outlines, or rather I saw outline drawings of them, bright on a
dark ground. I can compare these drawings less to chalk drawings on
a blackboard than to drawings made with phosphorus on a dark wall
at night, though the phosphorus would show luminous vapors which
were absent from my lines. If I wished, for example, to see a face,
without intending that of a particular person, I saw the outline of a
profile against the dark background. When I tried to repeat an eX«
* Geo, Herm. Meyer, Untersuchungen iib. d. Physiol, d. Nervenfaser
(1843} , p. 233. For other cases see Tuke's Influence of Mind upon Body,
chaps, i:. and vii.
t Meyer, op. cit p. 338.
IMAOINATIOK e*}
periment of the elder Darwin I saw only the edges of the die as brigbt
lines on a dark ground. Sometimes, however, I saw the die really white
and its edges black ; it was then on a paler ground. I could soon at
will change between a white die with black borders on a light field, and
a black die with white borders on a dark field ; and I can do this at any
moment now. After long practice . . . these experiments succeeded
better still. I can now call before my eyes almost any object which I
please, as a subjective appearance, and this in its own natural color and
illumination. I see them almost always on a more or less light or dark,
mostly dimly changeable ground. Even known faces I can see quite
sharp, with the true color of hair and cheeks. It is odd that I see
these faces mostly in profile, whereas those described [in the previous
extract] were all full-face. Here are some of the final results of these
experiments :
" 1) Some time after the pictures have arisen they vanish or change
into others, without my being able to prevent it.
' ' 2) When the color does not integrally belong to the object, I cannot
always control it. A face, e.g., never seems to me blue, but always in
its natural color ; a red cloth, on the other hand, I can sometimes
change to a blue one.
" 3) I have sometimes succeeded in seeing pure colors without objects;
they then fill the entire field of view.
" 4) I often fail to see objects which are not known to me, mere fic-
tions of my fancy, and instead of them there will appear familiar ob-
jects of a similar sort ; for instance, I once tried to see a brass sword-
hilt with a brass guard, instead of which the more familiar picture of a
rapier-guard appeared.
" 5) Most of these subjective appearances, especially when they were
bright, left after-images behind them when the eyes were quickly
opened during their presence. For example, I thought of a silver stir-
rup, and after I had looked at it a while I opened my eyes and for a
long while afterwards saw its after-image.
" These experiments succeeded best when I lay quietly on my back
and closed my eyes. I could bear no noise about me, as this kept the
vision from attaining the requisite intensity. The experiments succeed
with me now so easily that I am surprised they did not do so at first,
and I feel as though they ought to succeed with everyone. The im-
portant point in them is to get the image suflBciently intense by the ex-
clusive direction of the attention upon it, and by the removal of all
disturbing impressions." *
Urn negative after-images which succeeded upon Meyer's
imagination when he opened his eyes are a liighlj interest-
ing, though rare, phenomenon. So far as I know there is
* Meyer, op. cit. pp. 238-41.
68 P8TGM0L007.
only one other published report of a similar experience.* It
would seem that in such a case the neural process corre-
sponding to the imagination must be the entire tract con-
cerned in the actual sensation, even down as far as the
retina. This leads to a new question to which we may
now turn — of what is
THE NEUKAIi PKOCBSS -WHICH UNDEBLIES IMAGINATION P
The commonly-received idea is that it is only a milder
degree of the same process which took place when the
thing now imagined was sensibly perceived. Professor
Bain writes:
*' Since a sensation in the first instance diffuses nerve-currents
through the interior of the brain outwards to the organs of expression
and movement,— the persistence of that sensation, after the outward
exciting cause is withdrawn, can be but a continuance of the same dif-
fusive currents, perhaps less intense, but not otherwise different. The
shock remaining in the ear and brain, after the sound of thunder, must
pass through the same circles, and operate in the same way as during
the actual sound. We can have no reason for believing that, in this
self-sustaining condition, the impression changes its seat, or passes into
some new circles that have the special property of retaining it. Every
part actuated after the shock must have been actuated hy the shock,
only more powerfully. With this single difference of intensity, the mode
of existence of a sensation existing after the fact is essentially the same
as its mode of existence during the fact. . . . Now if this be the case
with impressions persisting when the cause has ceased, what view are
we to adopt concerning impressions reproduced by mental causes alone,
or without the aid of the original, as in ordinary recollection ? What
is the manner of occupation of the brain with a resuscitated feeling of
resistance, a smell or a sound ? There is only one answer that seems
admissable. The renewed feeling occupies the very same parts^ and in
the same manner, as the original feeling, and no other parts, nor in
any other assignable manner. I imagine that if our present knowledge
of the brain had been present to the earliest speculators, this is the only
* That of Dr. Ch. Fere in the Revue Philosophique, xx. 364. Johannes
Mllller's account of hypnagogic hallucinations floating before the eyes for
A few moments after these had been opened, seems to belong more to the
category of spontaneous hallucinations (see his Physiology, London, 1842,
p. 1394). It is impossible to tell whether the words in Wundt's Vorle-
sungen, i. 387, refer to a personal experience of his own or not ; probably
not. 11 va sans dire that an inferior visualizer like myself can get no such
after-images. Nor have I as yet succeeded in getting report of any from
my students.
IMAGINATION. 69
hypothesis that would have occurred to them. For where should a
past feeling be embodied, if not in the same organs as the feeling when
present ? It is only in this way that its identity can be preserved ; a
feeling differently embodied would be a different feeling."*
It is not plain from Professor Bain's text whether by
the * same parts ' he means only the same parts inside the
brain, or the same peripheral parts also, as those occupied by
the original feeling. The examples which he himself pro-
ceeds to give are almost all cases of imagination of move-
ment, in which the peripheral organs are indeed affected,
for actual movements of a weak sort are found to accom-
pany the idea. This is what we should expect. All cur-
rents tend to run forward in the brain and discharge into
the muscular system ; and the idea of a movement tends to
do this with peculiar facility. But the question remains :
Do currents run backward, so that if the optical centres
(for example) are excited by * association ' and a visual ob-
ject is imagined, a current runs doivn to the retina also,
and excites that sympathetically with the higher tracts ?
In other v^ords, can peripheral sense-organs he excited from
above, or only from without ? Are they excited in imagi-
nation ? Professor Bain's instances are almost silent as to
this point. All he says is this :
" We might think of a blow on the hand until the skin were actually
irritated and inflamed. The attention very much directed to any part
of the body, as the great toe, for instance, is apt to produce a distinct
feeling in the part, which we account for only by supposing a revived
nerve-current to flow there, making a sort of false sensation, an influ-
ence from within mimicking the influences from without in sensation
proper. — (See the writings of Mr. Braid, of Manchester, on Hypnotism,
etc.)"
If I may judge from my own experience, all feelings of
this sort are consecutive upon motor currents invading the
skin and producing contraction of the muscles there, the
muscles whose contraction gives * goose-flesh ' when it takes
place on an extensive scale. I never get a feeling in the
skin, however strongly I imagine it, until some actual
change in the condition of the skin itself has occurred.
The truth seems to be that the cases where peripheral
* Senses and Intellect, p. 888.
70 PaTOHOLOOT.
sense-organs are directly excited in consequence of imagi
nation are exceptional rarities, if they exist at all. In com-
mon cases of imagination it would seem more natural to suppose
that the seat of the process is purely cerebral^ and that the sense-
organ is left out. Reasons for such a conclusion would be
briefly these :
1) In imagination the starting-point of the process must
be in the brain. Now we know that currents usually flow
one way in the nervous system ; and for the peripheral sense-
organs to be excited in these cases, the current would have
to flow backward.
2) There is between imagined objects and felt objects
a difference of conscious quality which may be called al-
most absolute. It is hardly possible to confound the live-
liest image of fancy with the weakest real sensation. The
felt object has a plastic reality and outwardness which the
imagined object wholly lacks. Moreover, as Fechner says,
in imagination the attention feels as if drawn backwards to
the brain ; in sensation (even of after-images) it is directed
forward towards the sense-organ.* The difference between
the two processes feels like one of kind, and not like a mere
*more' or * less ' of the same.f If a sensation of sound
were only a strong imagination, and an imagination a weak
sensation, there ought to be a border-line of experience
where we never could tell whether we were hearing a weak
sound or imagining a strong one. In comparing a present
sensation felt with a past one imagined, it will be remem-
bered that we often judge the imagined one to have been tJie
stronger (see above, p. 500, note). This is inexplicable if
the imagination be simply a weaker excitement of the sen-
sational process.
To these reasons the following objections may be made :
To 1) : The current demonstrably does flow backward
* See above, Vol. II. p. 50, note.
f V. Kandinsky (Kritische u. klinische Betrachtungen im Gebiete der
Sinnestauschungen (Berlin, 1885), p. 135 ff.) insists that in even the live-
liest pseudo-hallucinations (see below, Chapter XX), which may be re-
garded as the intensest possible results of the imaginative process, there
Is no outward objectivity perceived in the thing represented, and that a
gamer Ahgrund separates these ' ideas' from true hallucination and objec-
tlTe perception.
IMAGINATION. 71
down the optic nerve in Meyer's and Fere's negative after-
image. Therefore it can flow backward ; therefore it may
flow backward in some, however slight, degree, in all imag-
ination.*
To 2) : The difference alleged is not absolute, and sensa-
tion and imagination are hard to discriminate whera the
sensation is so weak as to be just perceptible. At night
hearing a very faint striking of the hour by a far-off clock,
our imagination reproduces both rhythm and sound, and it
is often difiicult to tell which was the last real stroke. So
of a baby crying in a distant part of the house, we are un-
certain whether we still hear it, or only imagine the soundo
Certain violin-players take advantage of this in diminuendo
terminations. After the pianissimo has been reached
they continue to bow as if still playing, but are careful not
to touch the strings. The listener hears in imagination a
* It seems to also flow backwards in certain hypnotic hallucinations.
Suggest to a ' Subject ' in the hypnotic trance that a sheet of paper has a
red cross upon it, then pretend to remove the imaginary cross, whilst you
tell the Subject to look fixedly at a dot upon the paper, and he will pres-
ently tell you that he sees a ' bluish-green ' cross. The genuineness of the
result has been doubted, but there seems no good reason for rejecting M.
Binet's account (Le Magnetisme Animal, 1887, p. 188). M. Binet, following
M. Parinaud, and on the faith of a certain experiment, atone time believed,
the optical brain-centres and not the retina to be the seat of ordinary nega-
tive after-images. The experiment is this : Look fixedly, with one eye
open, at a colored spot on a white background. Then close that eye and
look fixedly with the otTier eye at a plain surface. A negative after-image
of the colored spot will presently appear. (Psychologic du Raisonnement,
1886, p. 45.) But Mr. Delabarre has proved (American Journal of Psy-
chology, II. 326) that this after-image is due, not to a higher cerebral pro-
cess, but to the fact that the retinal process in the closed eye affects
consciousness at certain moments, and that its object is then projected
into the field seen by the eye which is open. M. Binet informs me that
ne is converted by the proofs given by Mr. Delabarre.
The fact reuiaius, however, that the negative after-images of Herr Meyer,
M. Fere, and the hypnotic subjects, form an exception to all that we know
of nerve-currents, if they are due to a retiuent centrifugal current to the
retina. It may be that they will hereafter be explained in some other way.
Meanwhile we can only write them down as a paradox. Sig. Sergi's theory
that there is always a refluent wave in perception hardly merits serious con-
sideration (Psychologic Physiologique, pp. 99, 189). Sergi's theory hiui
recently been reatfirmed with almost incredible crudity by Lombroso and
Ottolenghi in the Revue Philosophique, xxix. 70 (Jan. 1890).
72 P8T0n0L0Q7,
degree of sound fainter still than the preceding pianissimo
This phenomenon is not confined to hearing :
*' If we slowly approach our finger to a surface of water, we often
deceive ourselves about the moment in which the wetting occurs. Th«
apprehensive patient believes himself to feel the knife of the surgeon
whilst it is still at some distance." *
Visual perception supplies numberless instances in which
the same sensation of vision is perceived as one object or
another according to the interpretation of the mind. Many
of these instances will come before us in the course of the
next two chapters ; and in Chapter XIX similar illusions
will be described in the other senses. Taken together, all
these facts would force us to admit that the subjective
differeTice between imagined and felt objects is less absolute
than has been claimed^ and that the cortical processes which
underlie imagination and sensation are not quite as discrete
as one at first is tempted to suppose. That peripheral sen-
sory processes are ordinarily involved in imagination seems
improbable ; that they may sometimes be aroused from the cortex
downioards cannot, however, be dogmatically denied.
The imagination-process can then pass over into the sensa-
tion-process. In other words, genuine sensations can be
centrally originated. When we come to study hallucina-
tions in the chapter on Outer Perception, we shall see that
this is by no means a thing of rare occurrence. At present,
however, we must admit that normally the two processes do
NOT pass over into each other ; and we must inquire why.
One of two things must be the reason. Either
1. Sensation-processes occupy a different locality from
imagination-processes ; or
2. Occupying the same locality, they have an intensity
which under normal circumstances currents from other
cortical regions are incapable of arousing, and to produce
which currents from the periphery are required.
It seems almost certain (after what was said in Chapter
II. pp. 49-51) that the imagination-process differs from the
sensation-process by its intensity rather than by its locality.
However it may be with lower animals, the assumption that
* Lotze, Med. Psych, p. 509.
IMAGINATION, 78
ideational and sensorial centres are locally distinct appears
to be supported by no facts drawn from the observation of
human beings. After occipital destruction, the hemianop-
sia which results in man is sensorial blindness, not mere
loss of optical ideas. Were there centres for crude optical
sensation below the cortex, the patients in these cases
would still feel light and darkness. Since they do not pre-
serve even this impression on the lost half of the field, we
must suppose that there are no centres for vision of any
sort whatever below the cortex, and that the corpora quadri-
gemina and other lower optical ganglia are organs for reflex
movement of eye-muscles and not for conscious sight.
Moreover there are no facts which oblige us to think that,
within the occipital cortex, one part is connected with sen-
sation and another with mere ideation or imagination. The
pathological cases assumed to prove this are all better ex-
plained by disturbances of conduction between the optical
and other centres (see p. 50). In bad cases of hemianopsia
the patient's images depart from him together with his sen-
sibility to light. They depart so completely that he does not
even know what is the matter with him. To perceive that
one is blind to the right half of the field of view one must
have an idea of that part of the field's possible existence.
But the defect in these patients has to be revealed to them
by the doctor, they themselves only knowing that there is
* something wrong ' with their eyes. What you have no idea
of you cannot miss ; and their not definitely missing this
great region out of their sight seems due to the fact that their
very idea and memory of it is lost along with the sensation.
A man blind of his eyes merely, sees darkness. A man blind
of his visual brain-centres can no more see darkness out of
the parts of his retina which are connected with the brain-
lesion than he can see it out of the skin of his back. He
cannot see at all in that part of the field ; and he cannot
think of the light which he ought to be feeling there^ for the
very notion of the existence of that particular * there ' is
cut out of his mind.*
* See an important article by Binet in the Revue Philosophique, xxvi.
481 (1888) ; also Dufour, in Revue Med. de la Suisse Romande, 1889. No.
S, cited in the Neurologisches Centralblatt, 1890. d ^
74 PatCHOLOQT,
Now if we admit that sensation and imagination are due
to the activity of the same centres in the cortex, we can see a
very good teleological reason why they should correspond
to discrete kinds of process in these centres, and why the
process which gives the sense that the object is really there
ought normally to be arousable only by currents entering
from the periphery and not by currents from the neighbor-
ing cortical parts. We can see, in short, why the sensational
process ought to be discontinuotis ivith all normal ideational
processes, however interne. For, as Dr. Miinsterberg justly
observes :
*' Were there not this peculiar arrangement we should not distinguish
reality and fantasy, our conduct would not be accommodated to the
facts about us, but would be inappropriate and senseless, and we could
not keep ourselves alive. . . . That our thoughts and memories should
be copies of sensations with their intensity greatly reduced is thus a
consequence deducible logically from the natural adaptation of the
cerebral mechanism to its environment." *
Mechanically the discontinuity between the ideational
and the sensational kinds of process must mean that when
the greatest ideational intensity has been reached, an order
of resistanxie presents itself which only a new order of force
can break through. The current from the periphery is the
new order of force required ; and what happens after the
resistance is overcome is the sensational process. We may
suppose that the latter consists in some new and more vio-
lent sort of disintegration of the neural matter, which now
explodes at a deeper level than at other times.
Now how shall we conceive of the * resistance ' which
prevents this sort of disintegration from taking place, this
sort of intensity in the process from being attained, so
much of the time ? It must be either an intrinsic resist-
ance, some force of cohesion in the neural molecules them-
selves ; or an extrinsic influence, due to other cortical cells.
When we come to study the process of hallucination we
shall see that both factors must be taken into account.
There is a degree of inward molecular cohesion in our
brain-cells which it probably takes a sudden inrush of
♦Die Wlllenshandlung (1888), pp. 129-40.
IMAGINATION, 76
destructive energy to spring apart. Incoming peripheral
currents possess this energy from the outset. Currents
from neighboring cortical regions might attain to it if they
could accumulate within the centre which we are supposed
to be considering. But since during waking hours every
centre communicates with others by association-paths,
no such accumulation can take place. The cortical cur-
rents which run in run right out again, awakening the next
ideas; the level of tension in the cells does not rise to the
higher explosion-point; and the latter must be gained by a
sudden current from the periphery or not at alL
CHAPTEE XIX.
THE PERCEPTION OF 'THINGS.'
PEKCBPTION AND SENSATION COMPAKED.
A PURE sensation we saw above, p. 7, to be an abstrac-
tion never realized in adult life. Any quality of a thing
which affects our sense-organs does also more than that :
it arouses processes in the hemispheres which are due to
the organization of that organ by past experiences, and the
result of which in consciousness are commonly described
as ideas which the sensation suggests. The first of these
ideas is that of the thing to which the sensible quality
belongs. The consciousness of particular material things
'present to sense is nowadays called perception.^ The con-
sciousness of such things may be more or less complete ;
it may be of the mere name of the thing and its other essen-
tial attributes, or it may be of the thing's various remoter
relations. It is impossible to draw any sharp line of dis-
tinction between the barer and the richer consciousness,
because the moment we get beyond the first crude sensa-
tion all our consciousness is a matter of suggestion, and
the various suggestions shade gradually into each other,
being one and all products of the same psychological
machinery of association. In the directer consciousness
fewer, in the remoter more, associative processes are
brought into play.
* The word Perception, however, has been variously used. For histor-
ical notices, see Hamilton's Lectures on Metaphysics, ii. 96. For Hamil-
ton perception is ' the consciousness of external objects ' {ib. 28). Spencer
defines it oddly enough as "a discerning of the relation or relations be-
tween states of consciousness partly presentative and partly representative ;
which states of consciousness must be themselves known to the extent in-
volved in the knowledge of their relations " (Psychol., § 355).
76
THB PERCBPTION OF THINGS. Tl
Perception thus differs from sensation hy the consciousness
of farther fcucts associated with the object of the sensation :
" When I lift my eyes from the paper on which I am writing I see
the chairs and tables and walls of my room, each of its proper shape
and at its proper distance. I see, from my window, trees and mead-
ows, and horses and oxen, and distant hills. I see each of its proper
size, of its proper form, and at its proper distance ; and these particu-
lars appear as immediate informations of the eye, as the colors which I
see by means of it. Yet philosophy has ascertained that we derive noth-
ing from the eye whatever but sensations of color. . . . How, then, is it
that we receive accurate information, by the eye, of size and shape and
distance ? By association merely. The colors upon a body are different,
according to its figure, its shape, and its size. But the sensations of
color and what we may here, for brevity, call the sensations of ex-
tension, of figure, of distance, have been so often united, felt in con-
junction, that the sensation of the color is never experienced without
raising the ideas of the extension, the figure, the distance, in such inti-
mate union with it, that they not only cannot be separated, but are ac-
tually supposed to be seen. The sight, as it is called, of figure, or dis-
tance, appearing as it does a simple sensation, is in reality a complex
state of consciousness— a sequence in which the antecedent, a sensation
of color, and the consequent, a number of ideas, are so closely com-
bined by association that they appear not one idea, but one sensation."
This passage from James Mill * gives a clear statement
of the doctrine which Berkeley in his Theory of Vision
made for the first time an integral part of Psychology.
Berkeley compared our visual sensations to the words of a
language, which are but signs or occasions for our intel-
lects to pass to what the speaker means. As the sounds
called words have no inward affinity with the ideas they
signify, so neither have our visual sensations, according to
Berkeley, any inward affinity with the things of whose
presence they make us aware. Those things are tangibles;
their real properties, such as shape, size, mass, consistency,
position, reveal themselves only to touch. But the visible
signs and the tangible significates are by long custom so
" closely twisted, blended, and incorporated together, and
the prejudice is so confirmed and riveted in our thoughts
by a long tract of time, by the use of language, and want of
reflection," f that we think we see the whole object, tangible
and visible alike, in one simple indivisible act.
* Analysis, i. 97.
f Theory of Vision, 51.
78 PSTGHOLOQT.
Sensational and reproductive brain-processes combined^ then^
are what give us the content of our perceptions. Every con-
crete particular material thing is a conflux of sensible
qualities, with which we have become acquainted at vari-
ous times. Some of these qualities, since they are more
constant, interesting, or practically important, we regard as
essential constituents of the thing. In a general way, such
are the tangible shape, size, mass, etc. Other properties,
being more fluctuating, we regard as more or less acciden-
tal or inessential. We call the former qualities the reality,
the latter its appearances. Thus, I hear a sound, and say
* a horse-car ' ; but the sound is not the horse-car, it is
one of the horse-car's least important manifestations. The
real horse-car is a feelable, or at most a feelable and visi-
ble, thing which in my imagination the sound calls up. So
when I get, as now, a brown eye-picture with lines not
parallel, and with angles unlike, and call it my big solid
rectangular walnut library-table, that picture is not the
table. It is not even like the table as the table is for vision,
when rightly seen. It is a distorted perspective view of three
of the sides of what I mentally perceive (more or less) in its
totality and undistorted shape. The back of the table, its
square corners, its size, its heaviness, are features of which
I am conscious when I look, almost as I am conscious of
its name. The suggestion of the name is of course due to
mere custom. But no less is that of the back, the size,
weight, squareness, etc.
Nature, as Reid says, is frugal in her operations, and
will not be at the expense of a particular instinct to give
us that knowledge which experience and habit will soon
produce. Reproduced sights and contacts tied together
with the present sensation in the unity of a thing with a
name, these are the complex objective stuff out of which
my actually perceived table is made. Infants must go
through a long education of the eye and ear before they
can perceive the realities which adults perceive. Every
perception is an acquired perception.'*'
* The educative process is particularly obvious in the case of the ear,
for all sudd^i sounds seem alarming to babies. The familiar noises of
THE PERCEPTION OF THINGS. 79
Perception may then he defined^ in Mr. Sully's words, as
that process by which the mind
*' supplements a sense-impression by an accompaniment or escort of re
vived sensations, the whole aggregate of actual and revived sensations
being solidified or ' integrated ' into the form of a percept, that is, an
apparently immediate apprehension or cognition of an object now
present in a particular locality or region of space." *
Every reader's mind will supply abundant examples of
the process here described ; and to write them down would
be therefore both unnecessary and tedious. In the chapter
on Space we have already discussed some of the more inter-
esting ones ; for in our perceptions of shape and position it
is really difficult to decide how much of our sense of the ob-
ject is due to reproductions of past experience, and how
much to the immediate sensations of the eye. I shall ac-
cordingly confine myself in the rest of this chapter to cer-
tain additional generalities connected with the perceptive
process.
The first point is relative to that * solidification ' or * in-
tegration,' whereof Mr. Sully speaks, of the present with
the absent and merely represented sensations. Cerebrally
taken, these words mean no more than this, that the pro-
cess aroused in the sense-organ has shot into various
paths which habit has already organized in the hemi-
spheres, and that instead of our having the sort of con-
sciousness which would be correlated with the simple sen-
sorial process, we have that which is correlated with this
more complex process. This, as it turns out, is the con-
sciousness of that more complex * object,' the whole * thing,'
instead of being the consciousness of that more simple
object, the few qualities or attributes which actually im-
press our peripheral nerves. This consciousness must have
the unity which every ' section ' of our stream of thought
retains so long as its objective content does not sensibly
house and street keep them in constant trepidation until such time as they
have either learned the objects which emit them, or have become bluntei
to them by frequent experience of their innocuity.
* Outlines, p. 153.
80 PSYGHOLOQT,
change. More than this we cannot say ; we certainly
ought not to say what usually is said by psychologists, and
treat the perception as a sum of distinct psychic entities,
the present sensation namely, pltis a lot of images from the
past, all * integrated ' together in a way impossible to de-
scribe. The perception is one state of mind or nothing — as
I have already so often said.
In many cases it is easy to compare the psychic results
of the sensational with those of the perceptive process. We
then see a marked difference in the way in which the im-
pressed portions of the object are felt, in consequence of
being cognized along with the reproduced portion, in the
higher state of mind. Their sensible quality changes un-
der our very eye. Take the already-quoted catch. Pas de
lieu BhSne que nous : one may read this over and over again
without recognizing the sounds to be identical with those
of the words paddle your own canoe. As we seize the
English meaning the sound itself appears to change.
Yerbal sounds are usually perceived with their meaning at
the moment of being heard. Sometimes, however, the
associative irradiations are inhibited for a few moments
(the mind being preoccupied with other thoughts) whilst
the words linger on the ear as mere echoes of acoustic sen-
sation. Then, usually, their interpretation suddenly occurs.
But at that moment one may often surprise a change in the
very feel of the word. Our own language would sound
very different to us if we heard it without understanding,
as we hear a foreign tongue. Rises and falls of voice, odd
sibilants and other consonants, would fall on our ear in a
way of which we can now form no notion. Frenchmen say
that English sounds to them like the gazouillement des oiseaux
— an impression which it certainly makes on no native ear.
Many of us English would describe the sound of Russian
in similar terms. All of us are conscious of the strong in-
flections of voice and explosives and gutturals of German
speech in a way in which no German can be conscious of
them.
This is probably the reason why, if we look at an isolated
printed word and repeat it long enough, it ends by assuming
an entirely unnatural aspect. Let the reader try this with
THE PERCEPTION OF THINGS. 81
any word on this page. He will soon begin to wonder if it
can possibly be the word he has been using all his life with
that meaning. It stares at him from the paper like a glass
eye, with no speculation in it. Its body is indeed there, but
its soul is fled. It is reduced, by this new way of attending
to it, to its sensational nudity. We never before attended to
it in this way, but habitually got it clad with its meaning
the moment we caught sight of it, and rapidly passed from
it to the other words of the phrase. We apprehended it,
in short, with a cloud of associates, and thus perceiving it,
we felt it quite otherwise than as we feel it now divested
and alone.
Another well-known change is when we look at a land-
scape with our head upside down. Perception is to a cer-
tain extent baffled by this manoeuvre ; gradations of dis-
tance and other space-determinations are made uncertain ;
the reproductive or associative processes, in short, decline ;
and, simultaneously with their diminution, the colors grow
richer and more varied, and the contrasts of light and shade
more marked. The same thing occurs when we turn a
painting bottom upward. We lose much of its meaning,
but, to compensate for the loss, we feel more freshly the
value of the mere tints and shadings, and become aware of
any lack of purely sensible harmony or balance which they
may show.* Just so, if we lie on the floor and look up at
the mouth of a person talking behind us. His lower lip
here takes the habitual place of the upper one upon our
retina, and seems animated by the most extraordinary and
unnatural mobility, a mobility which now strikes us be-
cause (the associative processes being disturbed by the un-
accustomed point of view) we get it as a naked sensation
and not as part of a familiar object perceived.
On a later page other instances will meet us. For the
present these are enough to prove our point. Once more
we find ourselves driven to admit that when qualities of an
object impress our sense and we thereupon perceive the
object, the sensation as such of those qualities does not
♦ Cf. Helmholtz, Optik, pp. 433, 723, 728, 772 , and Spencer, Psychol-
ogy, Tol. n. p. 249, note.
82 P8TCE0L0OT.
still exist inside of the perception and form a constituent
thereof. The sensation is one thing and the perception
another, and neither can take place at the same time with
the other, because their cerebral conditions are not the
same. They may resemble each other, but in no respect are
they identical states of mind.
PBBOEPTION IS OF DEFINITE AND PBOBABLE THINGS.
The chief cerebral conditions of perception are the paths
of association irradiating from the sense-impression, which
may have been already formed. If a certain sensation be
strongly associated with the attributes of a certain thing,
that thing is almost sure to be perceived when we get the
sensation. Examples of such things would be familiar
people, places, etc., which we recognize and name at a
glance. But where the sensation is associated ivith more than
one reality^ so that either of two discrepant sets of resid-
ual properties may arise, the perception is doubtful and
vacillating, and the most that can then be said of it is that it
will be of a probable thing, of the thing which would most
usually have given us that sensation.
In these ambiguous cases it is interesting to note that
perception is rarely abortive ; some perception takes place.
The two discrepant sets of associates do not neutralize each
other or mix and make a blur. What we more commonly
get is first one object in its completeness, and then the other
in its completeness. In other words, all brain-processes are
such as give rise to ivhat we may coll figueed consciousness. If
paths are irradiated at all, they are irradiated in consistent
systems, and occasion thoughts of definite objects, not mere
hodge-podges of elements. Even where the brain's func-
tions are half thrown out of gear, as in aphasia or dropping
asleep, this law of figured consciousness holds good. A
person who suddenly gets sleepy whilst reading aloud will
read wrong ; but instead of emitting a mere broth of sylla-
bles, he will make such mistakes as to read * supper-time '
instead of ' sovereign,' ' overthrow ' instead of * opposite,'
or indeed utter entirely imaginary phrases, composed of
several definite words, instead of phrases of the book. So
in aphasia : where the disease is mild the patient's mis'
THE PERCEPTION OF THINGS. 8B
takes consist in using entire wrong words instead of right
ones. Only in the gravest lesions does he become quite in«
articulate. These facts show how subtle is the associative
link ; how delicate yet how strong that connection among
brain-paths which makes any number of them, once excited
together, thereafter tend to vibrate as a systematic whole. A
small group of elements, * this,' common to two systems, A
and B, may touch off A or B according as accident decides
the next step (see Fig. 47). If it happen that a single point
leading from * this ' to B is momentarily a little more per-
vious than any leading from * this ' to A, then that little
advantage will upset the equilibrium in favor of the entire
system B. The currents will sweep first through that point
Fig. 47.
and thence into all the paths of B, each increment of ad-
vance making A more and more impossible. The thoughts
correlated with A and B, in such a case, will have objects
different, though similar. The similarity will, however,
consist in some very limited feature if the * this ' be small.
Thus the faintest sensations will give rise to the perception
of definite things if only they resemble those which the things
are wont to arouse. In fact, a sensation must be strong and
distinct in order not to suggest an object and, if it is a non-
descript feeling, really to seem one. The aurse of epilepsy,
globes of light, fiery vision, roarings in the ears, the sensa-
tions which electric currents give rise to when passed through
the head, these are unfigured because they are strong.
Weaker feelings of the same sort would probably suggest
objects. Many years ago, after reading Maury's book, Le
Sommeil et les RSves^ I began for the first time to observe
those ideas which faintly flit through the mind at all times,
words, visions, etc., disconnected with the main stream of
thought, but discernible to an attention on the watch for
84 P8TGH0L0GT.
them. A horse's head, a coil of rope, an anchor, are, for
example, ideas which have come to me unsolicited whilst I
have been writing these latter lines. They can often be
explained by subtle links of association, often not at all.
But I have not a few times been surprised, after noting
some such idea, to find, on shutting my eyes, an after-
image left on the retina by some bright or dark object
recently looked at, and which had evidently suggested
the idea. ' Evidently,' I say, because the general shape,
size, and position of object thought-of and of after-image
were the same, although the idea had details which the
retinal image lacked. We shall probably never know just
what part retinal after-images play in determining the train
of our thoughts. Judging by my own experiences I should
suspect it of being not insignificant.*
*The more or less geometrically regular phantasms which are pro-
duced by pressure on the eyeballs, cougestion of the head, inhalation of
anaesthetics, etc., might again be cited to prove that faint and vague excite-
ments of sense-organs are transformed into figured objects by the brain,
only the facts are not quite clearly interpretable ; and the figuring may
possibly be due to some retinal peculiarity, as yet unexplored. Beautiful
patterns, which would do for wall-papers, succeed each other when the
eyeballs are long pressed. Goethe's account of his own phantasm of a
flower is well known. It came in the middle of his visual field whenever
he closed his eyes and depressed his head, "unfolding itself and develop-
ing from its interior new flowers, formed of colored or sometimes green
leaves, not natural but of fantastic forms, and symmetrical as the rosettes
of sculptors," etc. (quoted in Milller's Physiology, Baly's tr., p. 1397). The
fortification- and zigzag-patterns, which are well-known appearances in the
field of view in certain functional disorders, have characteristics (steadiness,
coerciveness, blotting out of other objects) suggestive of a retinal origin —
this is why the entire class of phenomena treated of in this note seem to me
still doubtfully connected with the cerebral factor in perception of which
the text treats. — I copy from Taine's book on Intelligence (vol. i. p. 61)
the translation of an interesting observation by Prof. M. Lazarus, in which
the same effect of an after-image is seen. Lazarus himself proposes the
name of ' visionary illusions ' for such modifications of ideal pictures by
peripheral stimulations (Lehre von den Sinnestauschungen, 1867, p. 19).
" I was on the Kaltbad terrace at Rigi, on a very clear afternoon, and
attempting to make out the Waldbruder, a rock which stands out from
the midst of the gigantic wall of mountains surrounding it, on whose sum-
mits we see like a crown the glaciers of Titlis, Uri-Rothsdock, etc. I wai
looking alternately with the naked eye and with a spy-glass ; but could not
distinguish it with the naked eye. For the space of six to ten minutes I
had gazed steadfastly upon the mountains, whose color varied according
THE PERCEPTION OF THINGR 86
ILLUSIONS.
Let us now, for brevity's sake, treat A and B in Fig. 47
as if they stood for objects instead of brain-processes. And
let us furthermore suppose that A and B are, both of them,
objects which might probably excite the sensation which I
have called * thisy' but that on the present occasion A and
not B is the one which actually does so. If, then, on this
occasion ' this ' suggests A and not B, the result is a correct
perception. But if, on the contrary, ' this ' suggests B and
not A, the result is Sk false perception, or, as it is technically
called, an illusion. But the process is the same, whether
the perception be true or false.
to their several altitudes or declivities between violet, brown, and dark
green, and I had fatigued myself to no purpose, when I ceased looking
and turned away. At that moment I saw before me (I cannot recollect
whether my eyes were shut or open) the figure of an absent friend, like a
corpse. ... I asked myself at once how I had come to think of my absent
friend.— In a few seconds I regained the thread of my thoughts, which
my looking for the Waldbruder had interrupted, and readily found that the
idea of my friend had by a very simple necessity introduced itself among
them. My recollecting him was thus naturally accounted for. — But in
addition to this, he had appeared as a corpse. How was this ? — At this
moment, whether through fatigue or in order to think, I closed my eyes,
and found at once the whole field of sight, over a considerable extent,
covered with the same corpse-like hue, a greenish-yellow gray. 1 thought
at once that 1 had here the principle of the desired explanation, and
attempted to recall to memory the forms of other persons. And, in fact,
these forms too appeared like corpses ; standing or sitting, as I wished, all
had a corpse-like tint. The persons whom I wished to see did not all ap-
pear to me as sensible phantoms ; and again, when my eyes were open, I
did not see phantoms, or at all events only saw them faintly, of no deter-
mined color.— 1 then inquired how it was that phantoms of persons were
affected by and colored like the visual field surrounding them, how their
outlines were traced, and if their faces and clothes were of the same color.
But it was then too late, or perhaps the influence of reflection and exami'
nation had been too powerful. All grew suddenly pale, and the subjective
phenomenon, which might have lasted some minutes longer, had disap-
Deared, — It is plain that here an inward reminiscence, arising in accordance
with the laws of association, had combined with an optical after-image.
The excessive excitation of the periphery of the optic nerve, I mean th©
long-continued preceding sensation of my eyes when contemplating the
color of the mountain, had indirectly provoked a subjective and durable
sensation, that of the complemenatry color ; and my reminiscence, incor-
porating itself with this subjective sensation, became the corpse-like phan«
tom I have described.''
86 P8T0H0L0QT.
Note that in every illusion what is false is what is in-
ferred, not what is immediately given. The 'this,' if it
were felt by itself alone, would be all right, it only becomes
misleading by what it suggests. If it is a sensation of
sight, it may suggest a tactile object, for example, which
later tactile experiences prove to be not there. The so-called
* fallacy of the senses/ of which the ancient sceptics made so
much account t is not fallacy of the senses proper, hut rather of
the intellect y which interprets wrongly what the senses give,*
So much premised, let us look a little closer at these
illusions. They are due to two main causes. The wrong
object is perceived either because
1) Although not on this occasion the real cause, it is yet the
habitual, inveterate, or most probable cause of * this ; ' or because
2) The mind is temporarily full of the thought of that object,
and therefore * this ' is peculiarly prone to suggest it at this
moment.
I will give briefly a number of examples under each
head. The first head is the more important, because it
includes a number of constant illusions to which all men
are subject, and which can only be dispelled by much
experience.
Illusions of the First Type,
One of the oldest instances dates from Aristotle. Cross
two fingers and roll a pea, pen-
holder, or other small object be-
tween them. It will seem double.
Professor Croom Eobertson has
given the clearest analysis of this
illusion. He observes that if
Fig. 48. the object be brought into con-
tact first with the forefinger and next with the second finger,
the two contacts seem to come in at diiferent points of space.
* Cf . Th. Reid's Intellectual Powers, essay n. chap, xxii, and A. Binet,
in Mind, ix. 206. M. Binet points out the fact that what is fallaciously
inferred is always an object of some other sense than the ' this.' ' Optical
illusions ' are generally errors of touch and muscular sensibility, and the
fallaciously perceived object and the experiences which correct it are both
tactile in these casee.
THE PERCEPTION OF THINGS. 87
The forefinger-touch seems higher, though the finger is
really lower ; the second-finger-touch seems lower, though
the finger is really higher. " We perceive the contacts as
double because we refer them to two distinct parts of
space." The touched sides of the two fingers are normally
not together in space, and customarily never do touch one
thing ; the one thing which now touches them, therefore,
seems in two places, i.e. seems two things.*
There is a whole batch of illusions which come from
optical sensations interpreted by us in accordance with our
usual rule, although they are now produced by an unusual
object. The stereoscope is an example. The eyes see a
picture apiece, and the two pictures are a little disparate,
the one seen by the right eye being a view of the object
taken from a point slightly to the right of that from which
the left eye's picture is taken. Pictures thrown on the two
eyes by solid objects present this identical disparity.
Whence we react on the sensation in our usual way, and
perceia^e a solid. If the pictures be exchanged we perceive
a hollow mould of the object, for a hollow mould woulcj
cast just such disparate pictures as these. Wheatstone'a
instrument, the psetdoscope, allows us to look at solid
objects and see with each eye the other eye's picture. We
then perceive the solid object hollow, if it be an object which
might probably be holloiv^ but not otherwise. A human face,
e.g., never appears hollow to the pseudoscope. In this
irregularity of reaction on different objects, some seem
hollow, others not ; the perceptive process is true to its
law, which is always to react on the sensation in a deter-
minate and figured fashion if possible^ and in as probable
a fashion as the case admits. To couple faces and hollow
* The converse illusion is hard to bring about. The points a and b,
being normally in contact, mean to us the same space, and hence it might
be supposed that when simultaneously touched, as by a pair of callipers,
we should feel but one object, whilst as a matter of fact we feel two. It
should be remarked in explanation of this that an object placed between
the two fingers in their normal uncrossed position always awakens the sense
of two contacts. When the fingers are pressed together we feel one object to
be between them. And when the fingers are crossed, and their correspond-
ing points a and b simultaneously pressed, we do get something like th«
Illusion of singleness — that is, we get a very doubtful doubleness.
88 P8TCH0L007.
ness violates all our habits of association. For the same
reason it is very easy to make an intaglio cast of a face, or
the painted inside of a pasteboard mask, look convex, in-
stead of concave as they are.
Our sense of the position of things with respect to our
eye consists in suggestions of how we must move our hand
to touch them. Certain places of the image on the retina,
certain actively-produced positions of the eyeballs, are
normally linked with the sense of every determinate posi-
tion which an outer thing may come to occupy. Hence we
perceive the usual position, even if the optical sensation be
artificially brought from a different part of space. Prisms
warp the light-rays in this way, and throw upon the retina
the image of an object situated, say, at spot a of space in the
same manner in which (without the prisms) an object situ-
ated at spot h would cast its image Accordingly we feel
for the object at h instead of a. If the prism be before one
eye only we see the object at h with that eye, and in its
right position a with the other — in other words, we see it
double. If both eyes be armed with prisms with their angle
towards the right, we pass our hand to the right of all objects
when we try rapidly to touch them. And this illusory
sense of their position lasts until a new association is fixed,
when on removing the prisms a contrary illusion at first
occurs. Passive or unintentional changes in the position
of the eyeballs seem to be no more kept account of by the
mind than prisms are ; so we spontaneously make no allow-
ance for them in our perception of distance and movements.
Press one of the eyeballs into a strained position with the
finger, and objects move and are translocated accordingly,
just as when prisms are used.
Curious illusions of movement in objects occur whenever
the eyeballs move without our intending it. We shall learn
in the following chapter that the original visual feeling of
movement is produced by any image passing over the retina.
Originally, however, this sensation is definitely referred
neither to the object nor to the eyes. Such definite refer-
ence grows up later, and obeys certain simple laws. We
believe objects to move : 1) whenever we get the retinal
movement-feeling, but think our eyes are still ; and 2) when-
THE PERCEPTION OF THINOS. 89
ever we think that our eyes move, but fail to get the retinal
movement-feeling. We believe objects to be still, on the
contrary, 1) whenever we get the retinal movement-feeling,
but think )ur eyes are moving ; and 2) whenever we neither
think our eyes are moving, nor get the retinal movement-
feeling. Thus the perception of the object's state of motion
or rest depends on the notion we frame of our own eye's
movement. Now many sorts of stimulation make our eyes
move without our knowing it. If we look at a waterfall,
river, railroad train, or any body which continuously passes
in front of us in the same direction, it carries our eyes with
it. This movement can be noticed in our eyes by a by-
stander. If the object keep passing towards our left, our
eyes keep following whatever moving bit of it may have
caught their attention at first, until that bit disappears
from view. Then they jerk back to the right again, and
catch a new bit, which again they follow to the left, and so
on indefinitely. This gives them an oscillating demeanor,
slow involuntary rotations leftward alternating with rapid
voluntary jerks rightward. But the oscillations continue for
a while after the object has come to a standstill, or the
eyes are carried to a new object, and this produces the illu-
sion that things now move in the opposite direction. For
we are unaware of the slow leftward automatic movements
of our eyeballs, and think that the retinal movement-sen-
sations thereby aroused must be due to a rightward motion
of the object seen; whilst the rapid voluntary rightward
movements of our eyeballs we interpret as attempts to pur-
sue and catch again those parts of the object which have
been slipping away to the left.
Exactly similar oscillations of the eyeballs are produced
in giddiness, with exactly similar results. Giddiness is easi-
est produced by whirling on our heels. It is a feeling of
the movement of our own head and body through space,
and is now pretty well understood to be due to the irrita-
tion of the semi-circular canals of the inner ear.* When,
* Purkinje, Mach, and Breuer are the authors to whom we mainly owe
the explanation of the feeling of vertigo. I have found (American Jour-
nal of Otology, Oct. 1882) that in deaf-mutes (whose semi-circular canals
or entire auditory nerves must often be disorganized) there very frequently
exists no susceptibility to giddiness or whirling.
90 P8T0H0L00T.
after whirling, we stop, we seem to be spinning in the reverse
direction for a few seconds, and then objects appear to con-
tinue whirling in the same direction in which, a moment
previous, our body actually whirled. The reason is that
our eyes normally tend to maintain their field of view. If we
suddenly turn our head leftwards it is hard to make the
eyes follow. They roll in their orbits rightwards, by a
sort of compensating inertia. Even though we falsely
think our head to be moving leftwards, this consequence
occurs, and our eyes move rightwards — as may be observed
in any one with vertigo after whirling. As these move-
ments are unconscious, the retinal movement-feelings which
they occasion are naturally referred to the objects seen.
And the intermittent voluntary twitches of the eyes towards
the left, by which we ever and anon recover them from the
extreme rightward positions to which the reflex movement
brings them, simply confirm and intensify our impression
of a leftward-whirling field of view : we seem to ourselves
to be periodically pursuing and overtaking the objects in
their leftward flight. The whole phenomenon fades out
after a few seconds. And it often ceases if we voluntarily
fix our eyes upon a given point. ^
Optical vertigo, as these illusions of objective movement
are called, results sometimes from brain-trouble, intoxica-
tions, paralysis, etc. A man will awaken with a weakness
of one of his eye-muscles. An intended orbital rotation
will then not produce its expected result in the way of
retinal movement-feeling — whence false perceptions, of
which one of the most interesting cases will fall to be
discussed in later chapters.
There is an illusion of movement of the opposite sort,
with which every one is familiar at railway stations. Habit-
ually, when we ourselves move forward, our entire field of
view glides backward over our retina. When our move-
ment is due to that of the windowed carriage, car, or boat
* The involuntary continuance of the eye's motions is not the only cause
of the false perception in these cases. There is also a true negative after-
image of the original retinal movement-sensations, as we shall see iq
Chapter XX.
THE PERCEPTION OF THTNOS. 91
in which we sit, all stationary objects visible through the
window give us a sensation of gliding in the opposite
direction. Hence, whenever we get this sensation, of a
window with all objects visible through it moving in one
direction, we react upon it in our customary way, and per-
ceive a stationary field of view, over which the window, and
we ourselves inside of it, are passing by a motion of our
own. Consequently when another train comes alongside
of ours in a station, and fills the entire window, and, after
standing still awhile, begins to glide away, we judge that it
is our train which is moving, and that the other train is still.
If, however, we catch a glimpse of any part of the station
through the windows, or between the cars, of the other train,
the illusion of our own movement instantly disappears, and
we perceive the other train to be the one in motion. This,
again, is but making the usual and probable inference from
our sensation.*
Another illtcsion dice to movement is explained by Helm-
holtz. Most wayside objects, houses, trees, etc., look small
when seen out of the windows of a swift train. This is be-
cause we perceive them in the first instance unduly near.
And we perceive them unduly near because of their extra-
ordinarily rapid parallactic flight backwards. When we
ourselves move forward all objects glide backwards, as
aforesaid ; but the nearer they are, the more rapid is this
apparent translocation. Eelative rapidity of passage back-
wards is thus so familiarly associated with nearness that
when we feel it we perceive nearness. But with a given
size of retinal image the nearer an object is, the smaller do
we judge its actual size to be. Hence in the train, the
faster we go, the nearer do the trees and houses seem, and
the nearer they seem, the smaller do they look.f
Other illusions are due to the feeling of convergence being
wrongly interpreted. When we converge our eyeballs we
perceive an approximation of whatever thing we may be
looking at. Whatever things do approach whilst we look
* We never, so far as I know, get the converse illusion at a railroad sta-
tion and believe the other train to move v/hen it is still.
\ Helmholtz : Physiol. Optik, 365.
92 PSTCHOLOQT.
at them oblige us, so long as they are not very distant, to
converge our eyes. Hence approach of the thing is the prob-
able objective fact when we feel our eyes converging. Now in
most persons the internal recti muscles, to which converg-
ence is due, are weaker than the others ; and the entirely
passive position of the eyeballs, the position which they
assume when covered and looking at nothing in particular,
is either that of parallelism or of slight divergence. Make
a person look with both eyes at some near object, and then
screen the object from or^e of his eyes by a card or book,
The chances are that you will see the eye thus screened
turn just a little outwards. Remove the screen, and you
will now see it turn in as it catches sight of the object again.
The other eye meanwhile keeps as it was at first. To most
persons, accordingly, all objects seem to come nearer when,
after looking at them with one eye, both eyes are used ;
and they seem to recede during the opposite change. With
persons whose external recti muscles are insufficient, the
illusions may be of the contrary kind.
The size of the retinal image is a fruitful source of illusions.
Normally, the retinal image grows larger as the object draws
near. But the sensation yielded by this enlargement is
also given by any object which really grows in size with-
out changing its distance. Enlargement of retinal image
is therefore an ambiguous sign. An opera-glass enlarges
the moon. But most persons will tell you that she looks
smaller through it, only a great deal nearer and brighter.
They read the enlargement as a sign of approach ; and the
perception of approach makes them actually reverse the
sensation which suggests it — by an exaggeration of our
habitual custom of making allowance of the apparent en-
largement of whatever object approaches us, and reducing
it in imagination to its natural size. Similarly, in the theatre
the glass brings the stage near, but hardly seems to mag-
nify the people on it.
The well-known increased apparent size of the moon on the
horizon is a result of association and probability. It is seen
through vaporous air, and looks dimmer and duskier than
wken it rides on high; and it is seen over fields, trees,
THE PERCEPTION OF THIN08. 93
hedges, streams, and the like, which break up the interven-
ing space and make us the better realize the latter' s extent.
Both these causes make the moon seem more distant from
us when it is low ; and as its visual angle grows no less, we
deem that it must be a larger body, and we so perceive it.
It looks particularly enormous when it comes up directly
behind some well-known large object, as a house or tree,
distant enough to subtend an angle no larger than that of
the moon itself.^
The feeling of accommodation also gives rise to false per-
ceptions of size. Usually we accommodate our eyes for an
object as it approaches us. Usually under these circum-
stances the object throws a larger retinal image. But
believing the object to remain the same, we make allowance
for this and treat the entire eye-feeling which we receive
as significant of nothing but approach. When we relax our
accommodation and at the same time the retinal image
grows smaller, the probable cause is always a receding
object. The moment we put on convex glasses, however,
the accommodation relaxes, but the retinal image grows
larger instead of less. This is what would happen if our
object, whilst receding, grew. Such a probable object we
accordingly perceive, though with a certain vacillation as
to the recession, for the growth in apparent size is also a
probable sign of approach, and is at moments interpreted
accordingly. — Atropin paralyzes the muscles of accommo-
dation. It is possible to get a dose which will weaken
these muscles without laming them altogether. When a
known near object is then looked at we have to make the
same voluntary strain to accommodate, as if it were a great
deal nearer ; but as its retinal image is not enlarged in pro-
portion to this suggested approach, we deem that it must
have grown smaller than usual. In consequence of this
so-called micropsy, Aubert relates that he saw a man ap-
parently no larger than a photograph. But the small size
again made the man seem farther off. The real distance
* Cf . Berkeley's Theory of Vision, §§ 67-79 ; Helmholtz : Physiologische
Optik, pp. 630-1 ; Lechalas in Reuve Philosophique, xxvi. 49.
94 PBTCHOLOQT.
was two or three feet, and he seemed against the wall of
the room.^ Of these vacillations we shall have to speak
again in the ensuing chapter, f
Mrs. C. L. Franklin has recently described and explained
with rare acuteness an illusion of which the most curious
thing is that it was never noticed before. Take a single
pair of crossed lines (Fig. 49), hold them in a horizontal plane
before the eyes, and look along them, at such a
distance that with the right eye shut, 1, and with
the left eye shut, 2, looks like the projection of a
vertical line. Look steadily now at the point of
intersection of the lines with both eyes open, and
you will see a third line sticking up like a pin
through the paper at right angles to the plane of the
Fig. 49. two first liues. The explanation of this illusion is
very simple, but so circumstantial that I must refer for it to
Mrs. Franklin's own account.:]: Suffice it that images of the
two lines fall on 'corresponding' rows of retinal points,
and that the illusory vertical line is the only object capable
of throwing such images. A variation of the experiment
is this :
" In Fig. 50 the lines are all drawn so as to pass through a common
point. With a little trouble one eye can be put into the position of this
point — it is only necessary that the paper be held so that, with one eye
shut, the other eye sees all the lines leaning neither to the right nor to
the left. After a moment one can fancy the lines to be vertical staffs
standing out of the plane of the paper. . . . This illusion [says Mrs.
Franklin] I take to be of purely mental origin. When a line lies any-
where in a plane passing through the apparent vertical meridian of one
eye, and is looked at with that eye only. ... we have no very good
means of knowing how it is directed in that plane. . . . Now of the
lines in nature which lie anywhere within such a plane, by far the
* Physiol. Optik, p. 603.
t It seems likely that the strains in the recti muscles have something to
do with the vacillating judgment in these atropin cases. The internal recti
contract whenever we accommodate. They squint and produce double
vision when the innervation for accommodation is excessive. To see
singly, when straining the atropinized accommodation, the contraction of
our internal recti must be neutralized by a correspondingly excessive con«
traction of the external recti. But this is a sign of the object's recession, eta
X American Journal of Psychology, i. 101 ff.
THE PERCEPTION OF THINGS. 96
greater number are vertical lines. Hence we are peculiarly inclined to
think that a line which we perceive to be in such a plane is a vertical
line. But to see a lot of lines at once, all ready to throw their images
Fig. 50.
upon the vertical meridian, is a thing that has hardly ever happened to
us, except when they all have been vertical lines. Hence when that
happens we have a still stronger tendency to think that what we see
before us is a group of vertical lines."
In other words, we see, as always, the most probable
object.
The foregoing may serve as examples of the first type
of illusions mentioned on page 86. I could cite of course
many others, but it would be tedious to enumerate all the
thaumatropes and zoetropes, dioramas, and juggler's tricks
in which they are embodied. In the chapter on Sensation
we saw that many illusions commonly ranged under this
type are, physiologically considered, of another sort al-
together, and that associative processes, strictly so called,
have nothing to do with their production.
Illusions of the Second Type.
We may now turn to illusions of the second of the two
types discriminated on page 86. In this type we perceive a
wrong object because our mind is full of the thought of it
at the time, and any sensation which is in the least degree
connected with it touches off, as it were, a train already
laid, and gives us a sense that the object is really before
us. Here is a familiar example :
"If a sportsman, while shooting woodcock in cover, sees a bird
about the size and color of a woodcock get up and fly through the foil-
96 PaTOHOLOQT.
age, not having time to see more than that it is a bird of such a size
and color, he immediately supplies by inference the other qualities of a
woodcock, and is afterwards disgusted to find that he has shot a thrush.
I have done so myself, and could hardly believe that the thrush was the
bird I had fired at, so complete was my mental supplement to my visual
perception." *
As with game, so with enemies, ghosts, and the like.
Anyone waiting in a dark place and expecting or fearing
strongly a certain object will interpret any abrupt sensa-
tion to mean that object's presence. The boy playing ' I
spy,' the criminal skulking from his pursuers, the supersti-
tious person hurrying through the woods or past the church-
yard at midnight, the man lost in the woods, the girl who
tremulously has made an evening appointment with her
swain, all are subject to illusions of sight and sound which
make their hearts beat till they are dispelled. Twenty
times a day the lover, perambulating the streets with his
preoccupied fancy, will think he perceives his idol's bonnet
before him.
The Proof-reader's Illusiof. I remember one night in
Boston, whilst waiting for a * Mount Auburn ' car to bring
me to Cambridge, reading most distinctly that name upon
the signboard of a car on which (as I afterwards learned)
* North Avenue ' was painted. The illusion was so vivid
that I could hardly believe my eyes had deceived me. All
reading is more or less performed in this way.
*' Practised novel- or newspaper-readers could not possibly get on so
fast if they had to see accurately every single letter of evei*y word in
order to perceive the words. More than half of the words come out of
their mind, and hardly half from the printed page. Were this not so,
did we perceive each letter by itself, typographic errors in well-known
words would never be overlooked. Children, whose ideas are not yet
ready enough to perceive words at a glance, read them wrong if they
are printed wrong, that is, right according to the way of printing. In
a foreign language, although it may be printed with the same letters,
we read by so much the more slowly as we do not understand, or are
unable promptly to perceive the words. But we notice misprints all the
more readily. For this reason Latin and Greek and, still better,
Hebrew works are more correctly printed, because the proofs are better
corrected, than in German works. Of two friends of mine, one knew
much Hebrew, the other little ; the latter, however, gave instruction in
* JElomanes, Mental Evolution in Animals, d. 324.
THE PERCEPTION OF THINGS. 97
Hebrew in a gymnasium ; and when he called the other to help correct
his pupils' exercises, it turned out that he could find out all sorts of
little errors better than his friend, because the latter's perception of the
words as totals was too swift." *
Testimony to personal identity is proverbially fallacious for
similar reasons. A man has witnessed a rapid crime or
accident, and carries away his mental image. Later he is
confronted by a prisoner whom he forthwith perceives in
the light of that image, and recognizes or ' identifies ' as a
participant, although he may never have been near the
spot. Similarly at the so-called * materializing seances'
which fraudulent mediums give : in a dark room a man
sees a gauze-robed figure who in a whisper tells him she is
the spirit of his sister, mother, wife, or child, and falls upon
his neck. The darkness, the previous forms, and the ex-
pectancy have so filled his mind with piemonitory images
that it is no wonder he perceives what is suggested. These
fraudulent ' seances ' would furnish most precious docu-
ments to the psychology of perception, if they could only
be satisfactorily inquired into. In the hypnotic trance any
suggested object is sensibly perceived. In certain subjects
this happens more or less completely after waking from
the trance. It would seem that under favorable conditions
a somewhat similar susceptibility to suggestion may exist
in certain persons who are not otherwise entranced at all.
This suggestibility is greater in the lower senses than
in the higher. A German observer writes :
" We know that a weak smell or taste may be very diversely inter-
preted by us, and that the same sensation will now be named as one
thing and the next moment as another. Suppose an agreeable smell of
flowers in a room : A visitor will notice it, seek to recognize what it is,
*M. Lazarus: Das Leben d. Seele, ii (1857), p. 32. In the ordinary
hearing of speech half the words we seem to hear are supplied out of our
own head. A language with which we are perfectly familiar is under-
stood, even when spoken in low tones and far off. An unfamiliar language
is unintelligible under these conditions. If we do not get a very good seat
at a foreign theatre, we fail to follow the dialogue ; and what gives trouble
to most of us when abroad is not only that the natives speak so fast, but
that they speak so indistinctly and so low. The verbal objects for inter-
preting the sounds by are not alert and ready made in our minds, as they
are in our familiar mother-tongue, and do not start up at so faint a cue.
98 PSrCHOLOOT.
and at last perceive more and more distinctly that it is the perfume of
roses — until after all he discovers a bouquet of violets. Then suddenly
he recognizes the violet-smell, and wonders how he could possibly have
hit upon the roses.— Just so it is with taste. Try some meat whose
visible characteristics are disguised by the mode of cooking, and you
will perhaps begin by taking it for venison, and end by being quite
certain that it is venison, until you are told that it is mutton ; where-
upon you get distinctly the mutton flavor. — In this wise one may make
a person taste or smell what one will, if one only makes sure that he
shall conceive it beforehand as we wish, by saying to him : ' Doesn't
that taste just like, etc.?' or 'Doesn't it smell just like, etc.?' One
can cheat whole companies in this way ; announce, for instance, at a
meal, that the meat tastes 'high,' and almost every one who is not
animated by a spirit of opposition will discover a flavor of putrescence
which in reality is not there at all.
" In the sense ot feeling this phenomenon is less prominent, because
we get so close to the object that our sensation of it is never incomplete.
Still, examples may be adduced from this sense. On superficially feel-
ing of a cloth, one may confidently declare it for velvet, whilst it is
perhaps a long-haired cloth ; or a person may perhaps not be able to
decide whether he has put on woolen or cotton stockings, and, trying
to ascertain this by the feeling on the skin of the feet, he may become
aware that he gets the feeling of cotton or wool according as he thinks
of the one or the other. When the feeling in our fingers is somewhat
blunted by cold, we notice many such phenomena, being then more ex-
posed to confound objects of touch with one another." *
High authorities have doubted this power of imagination
to falsify present impressions of sense. t Yet it unquestion-
ably exists. Within the past fortnight I have been annoyed
by a smell, faint but unpleasant, in my library. My annoy-
ance began by an escape of gas from the furnace below
stairs. This seemed to get lodged in my imagination as a
sort of standard of perception; for, several days after the
furnace had been rectified, I perceived the *same smell'
again. It was traced this time to a new pair of India rubber
shoes which had been brought in from the shop and laid on
a table. It persisted in coming to me for several days,
however, in spite of the fact that no other member of the
family or visitor noticed anything unpleasant. My impres-
sion during part of this time was one of uncertainty whether
* G. H. Meyer, Untersuchungen, etc., pp. 242-3.
t Helmholtz, P. O. 438. The question will soon come before us again
in the chapter on the Perception of Space.
THE PERCEPTION OF THINGS. Q9
the smell was imaginary or real ; and at last it faded out.
Everyone must be able to give instances like this from the
smell-sense. When we have paid the faithless plumber for
pretending to mend our drains, the intellect inhibits the
nose from perceiving the same unaltered odor, until per-
haps several days go by. As regards the ventilation or
heating of rooms, we are apt to feel for some time as we
think we ought to feel. If we believe the ventilator is shut,
we feel the room close. On discovering it open, the oppres-
sion disappears.
An extreme instance is given in the following extract :
"A patient called at my oflBce one day in a state of great excitement
from the effects of an offensive odor in the horse-car she had come in,
and which she declared had probably emanated from some very sick
person who must have been just carried in it. There could be no doubt
that something had affected her seriously, for she was very pale, with
nausea, diflBculty in breathing, and other evidences of bodily and mental
distress. I succeeded, after some diflBculty and time, in quieting her,
and she left, protesting that the smell was unlike anything she had ever
before experienced and was something dreadful. Leaving my oflBce
soon after, it so happened that I found her at the street-corner, waiting
for a car: we thus entered the car together. She immediately called
my attention to the same sickening odor which she had experienced in
the other car, and began to be affected the same as before, when I
pointed out to her that the smell was simply that which always emanates
from the straw which has been in stables. She quickly recognized it as
the same, when the unpleasant effects which arose while she was possessed
with another perception of its character at once passed away." *
It is the same with touch. Everyone must have felt the
sensible quality change under his hand, as sudden contact
with something moist or hairy, in the dark, awoke a shock
of disgust or fear which faded into calm recognition of some
familiar object? Even so small a thing as a crumb of po-
tato on the table-cloth, which we pick up, thinking it a
crumb of bread, feels horrible for a few moments to our
fancy, and different from what it is.
Weight or muscular feeling is a sensation ; yet who has
not heard the anecdote of some one to whom Sir Humphry
Davy showed the metal sodium which he had just dis-
covered? "Bless me, how heavy it is!" said the man;
* C. F Taylor, Sensation and Pain. p. 37 (N. Y.,
100 PSYCBOLOOY.
showing that his idea of what metals as a class ought to be
had falsified the sensation he derived from a very light
substance.
In the sense of hearing, similar mistakes abound. I
have already mentioned the hallucinatory effect of mental
images of very faint sounds, such as distant clock-strokes
(above, p. IV). But even when stronger sensations of sound
have been present, everyone must recall some experience
in which they have altered their acoustic character as soon
as the intellect referred them to a different source. The
other day a friend was sitting in my room, when the clock,
which has a rich low chime, began to strike. " Hollo ! " said
he, "hear that hand-organ in the garden," and was sur-
prised at finding the real source of the sound. I had myself
some years ago a very striking illusion of the sort. Sitting
reading late one night, I suddenly heard a most formidable
noise proceeding from the upper part of the house, which
it seemed to fill. It ceased, and in a moment renewed it-
self. I went into the hall to listen, but it came no more.
Resuming my seat in the room, however, there it was again,
low, mighty, alarming, like a rising flood or the avant-
courier of an awful gale. It came from all space. Quite
startled, I again went into the hall, but it had already
ceased once more. On returning a second time to the room,
I discovered that it was nothing but the breathing of a little
Scotch terrier which lay asleep on the floor. The note-
worthy thing is that as soon as I recognized what it was, I
was compelled to think it a different sound, and could not
then hear it as I had heard it a moment before.
In the anecdotes given by Delbceuf and Reid, this was
probably also the case, though it is not so stated. Eeid
says:
" I remember that once lying abed, and having been put into a fright,
I heard my own heart beat; but I took it to be one knocking at the
door, and arose and opened the door oftener than once, before I dis-
covered that the sound was in my own breast." (Inquiry, chap. iv.
§1.)
Delbceuf s story is as follows :
" The illustrious P. J. van Beneden, senior, was walking one evening
with a friend along a woody hill near Chaudfontaine. ' Don't you
THE PERCEPTION OF THINQS. 101
hear,' said the friend, ' the noise of a hunt on the mountain?' M. van
Beneden listens and distinguishes in fact the giving-tongue of the dogs.
They listen some time, expecting from one moment to another to see a
deer bound by; but the voice of the dogs seems neither to recede nor
approach. At last a countryman comes by, and they ask him who it is
that can be hunting at this late hour. But he, pointing to some puddles
of water near their feet, replies: ' Yonder little animals are what you
hear.' And there there were in fact a number of toads of the species
Bombinator igneus. . . . This batrachian emits at the pairing season a
silvery or rather crystalline note. . . . Sad and pure, it is a voice in
nowise resembling that of hounds giving chase." *
The sense of siglit, as we have seen in studying Space,
is pregnant vrith illusions of both the types considered.
No sense gives such fluctuating impressions of the same
object as sight does. With no sense are we so apt to treat
the sensations immediately given as mere signs ; with none
is the invocation from memory of a thing, and the conse-
quent perception of the latter, so immediate. The * thing '
which we perceive always resembles, as we have seen, the
object of some absent sensation, usually another optical
figure which in our mind has come to be the standard of
reality; and it is this incessant reduction of our optical
objects to more * real ' forms which has led some authors
into the mistake of thinking that the sensations which
first apprehend them are originally and natively of no
from at alLf
Of accidental and occasional illusions of sight many
amusing examples might be given. Two will suffice. One
is a reminiscence of my own. I was lying in my berth in
a steamer listening to the sailors holystone the deck out-
side ; when, on turning my eyes to the window, I perceived
with perfect distinctness that the chief-engineer of the ves-
sel had entered my state-room, and was standing looking
through the window at the men at work upon the guards.
Surprised at his intrusion, and also at his intentness and
* Examen Critique de la Loi Psychophysique (1883), p. 61.
f Compare A. W Volkmann's essay * Ueber Ursprtlngliches und Erwor-
benes in den Raumanschauiingen,' on p. 139 of his Untersuchungen im
Gebiete der Optik ; and Chapter xiii of Hering's contribution to Her-
l's Handbuch der Physiologie, vol. iii.
102 PaTOHOLOQY.
immobility, I remained watching him and wondering how
long he would stand thus. At last I spoke ; but getting no
reply, sat up in my berth, and then saw that what I had
taken for the engineer was my own cap and coat hanging
on a peg beside the window. The illusion was complete ;
the engineer was a peculiar-looking man ; and I saw him
unmistakably ; but after the illusion had vanished 1 found
it hard voluntarily to make the cap and coat look like him
at all.
The following story, which I owe to my friend Prof.
Hyatt, is of a probably not uncommon class :
** During the winter of 1858, while in Venice, I had the somewhat
peculiar illusion which you request me to relate. I remember the cir-
cumstances very accurately because I have often repeated the story,
and have made an effort to keep all the attendant circumstances clear
of exaggeration. I was travelling with my mother, and we had taken
rooms at a hotel which had been located in an old palace. The room
in which I went to bed was large and lofty. The moon was shining
brightly, and I remember standing before a draped window, thinking
of the romantic nature of the surroundings, remnants of old stories of
knights and ladies, and the possibility that even in that room itself
love-scenes and sanguinary tragedies might have taken place. The
night was so lovely that many of the people were strolling through the
narrow lanes or so-called streets, singing as they went, and I laid aw^ake
for some time listening to these patrols of serenaders, and of course
finally fell asleep. I became aware that some one was leaning over me
closely, and that my own breathing was being interfered with; a decided
feeling of an unwelcome presence of some sort awakened me. As I
opened my eyes I saw, as distinctly as I ever saw any living person, a
draped head about a foot or eighteen inches to the right, and just above
my bed. The horror which took possession of my young fancy was
beyond anything I have ever experienced. The head was covered by a
long black veil which floated out into the moonlight, the face itself was
pale and beautiful, and the lower part swathed in the white band com-
monly worn by the nuns of Catholic orders. My hair seemed to rise
up, and a profuse perspiration attested the genuineness of the terror
which I felt. For a time I lay in this way, and then gradually gaining
more command over my superstitious terrors, concluded to try to grap-
ple with the apparition. It remained perfectly distinct until I reached
at it sharply with my hand, and then disappeared, to return again,
however, as soon as I sank back into the pillow. The second or third
grasp which I made at the head was not followed by a reappearance,
and I then saw that the ghost was not a real presence, but depended
upon the position of my head. If I moved my eyes either to the left or
THE PERCEPTION OF THINOS. 108
right of the original position occupied by my head when I awakened, the
ghost disappeared, and by returning to about the same position, I could
make it reappear with nearly the same intensity as at first. I presently
satisfied myself by these experiments that the illusion arose from the
effect of the imagination, aided by the actual figure made by a visual
section of the moonbeams shining through the lace curtains of the win-
dow. If I had given way to the first terror of the situation and cov-
ered up my head, I should probably have believed in the reality of the
apparition, since I have not by the slightest word, so far as I know, ex-
aggerated the vividness of my feelings."
THE PHYSIOLOGICAL PKOCESS IN PEKCEPTION.
Einough has now been said to prove the general law of
perception, which is this, that whilst part of what we per-
ceive comes through our senses from the object before us, another
'part (and it may be the larger part) always comes (in Laza-
rus's phrase) out of our own head.
At bottom this is only one case (and that the simplest
case) of the general fact that our nerve-centres are an organ
for reacting on sense-impressions, and that our hemispheres,
in particular, are given us in order that records of our private
past experience may co-operate in the reaction. Of course
such a general way of stating the fact is vague ; and all those
who follow the current theory of ideas will be prompt to
throw this vagueness at it as a reproach. Their way of de-
scribing the process goes much more into detail. The sen-
sation, they say, awakens ^ images ' of other sensations asso-
ciated with it in the past. These images ' fuse,' or are * com-
bined ' by the Ego with the present sensation into a new
product, the percept, etc., etc. Something so indistinguish-
able from this in practical outcome is what really occurs,
that one may seem fastidious in objecting to such a state-
ment, specially if have no rival theory of the elementary
processes to propose. And yet, if this notion of images
rising and flocking and fusing be mythological (and we have
all along so considered it), why should we entertain it unless
confessedly as a mere figure of speech ? As such, of course,
it is convenient and welcome to pass. But if we try to put
an exact meaning into it, all we find is that the brain reacts
by paths which previous experiences have worn, and makes
us usually perceive the probable things i.e., the thing by
104 PSYCHOLOGY.
which on previous occasions the reaction was most frequent-
ly aroused.
But we can, I think, without danger of being too
speculative, be a little more exact than this, and conceive
of a physiological reason why the felt quality of an object
changes when, instead of being apprehended in a mere sen-
sation, the object is perceived as a thing. All consciousness
seems to depend on a certain slowness of the process in the
cortical cells. The rapider currents are, the less feeling
they seem to awaken. If a region A, then, be so connected
with another region B that every current which enters A
immediately drains off into B, we shall not be very strongly
conscious of the sort of object that A can make us feel.
If B, on the contrary, has no such copious channel of dis-
charge, the excitement will linger there longer ere it diffuses
itself elsewhere, and our consciousness of the sort of ob-
ject that B makes us feel will be strong. Carrying this to
an ideal maximum, we may say that if A offer no resistance
to the transmission forward of the current, and if the cur-
rent terminate in B, then, no matter what causes may initiate
the current, we shall get no consciousness of the object
peculiar to A, but on the contrary a vivid sensation of the
object peculiar to B. And this will be true though at other
times the connection between A and B might lie less open,
and every current then entering A might give us a strong con-
sciousness of A's peculiar object. In other words, just in
proportion as associations are habitual, will the qualities of
the suggested thing tend to substitute themselves in con-
sciousness for those of the thing immediately there; or,
more briefly, just in proportion as an experience is probable
vnll it tend to he directly felt. In all such experiences the
paths lie wide open from the cells first affected to those
concerned with the suggested ideas. A circular after-image
on the receding wall or ceiling is actually seen as an ellipse,
a square after-image of a cross there is seen as slant-legged,
etc., because only in the process correlated with the vision
of the latter figures do the inward currents find a pause
(see the next chapter).
We must remember this when, in dealing with the eye,
we come to point out the erroneousness of the principle laid
THE PERCEPTION OF THINGS. 105
down by Eeid and Helmholtz that true sensationfe can
never be changed by the suggestions of experience.
A certain illusion of which I have not yet spoken affords
an additional illustration of this. When we vM to execute a
movement and the movement for some reason does not occur,
unless the sensation of the part's not moving is a strong one, we
are apt to feel a^ if the movement had actually taken place.
This seems habitually to be the case in anaesthesia of the
moving parts. Close the patient's eyes, hold his anaesthetic
arm still, and tell him to raise his hand to his head ; and
when he opens his eyes he will be astonished to find that
the movement has not taken place. All reports of anaesthetic
cases seem to mention this illusion. Sternberg who wrote on
the subject in 1885,^ lays it down as a law that the intention
to move is the same thing as the feeling of the motion. We
shall later see that this is false (Chapter XXV) ; but it
certainly may suggest the feeling of the motion with hallu-
cinatory intensity. Sternberg gives the following experi-
ment, which I find succeeds with at least half of those who
try it : Best your palm on the edge of the table with your
forefinger hanging over in a position of extreme flexion,
and then exert your will to flex it still more. The position
of the other fingers makes this impossible, and yet if we do
not look to see the finger, we think we feel it move. Ho
quotes from Exner a similar experiment with the jaws: Puu
some hard rubber or other unindentable obstacle between
* In the Proceedings of the American Society for Psychical Research, pp.
253-4. I have tried to account for some of the variations in this conscio'jf-
ness. Out of 140 persons whom I fo'md to feel their lost foot, some did so
dubiously. "Either they only feel it occasionally, or only when it pains
them, or only when they try to move it; or they only feel it when they
'think a good deal about it ' and make an effort to conjure it up. When
they 'grow inattentive,' the feeling 'flies back' or 'jumps back,' to the
stump. Every degree of consciousness, from complete and permanent hal-
lucination down to something hardly distinguishable from ordinary fancy,
seems represented in the sense of the missing extremity which these
patients say they have. Indeed I have seldom seen a more plausible lot of
evidence for the view that imagination and sensation are but differences of
vividness in an identical process than these confessions, taking them alto-
gether, contain. Many patients say they can hardly tell whether thej^
feel or fancy the limb. "
106 P8Y0H0L00T,
your back teeth and bite hard : you think you feel the jaiv
move and the front teeth approach each other, though in
the nature of things no movement can occur.* — The visu-
al suggestion of the path traversed by the finger-tip as the
locus of the movement-feeling in the joint, which we dis-
cussed on page 41, is another example of this semi-hallu-
cinatory power of the suggested thing. Amputated people,
as we have learned, still feel their lost feet, etc. This is a
necessary consequence of the law of specific energies, for if
the central region correlated with the foot give rise to any
feeling at all it must give rise to the feeling of a foot, f But
the curious thing is that many of these patients can will the
foot to move^ and when they have done so, distinctly /ee? the
movement to occur. They can, to use their own language,
* work ' or ' wiggle ' their lost toes. %
Now in all these various cases we are dealing with data
which in normal life are inseparably joined. Of all possi-
ble experiences, it is hard to imagine any pair more uni-
formly and incessantly coupled than the volition to move,
on the one hand, and the feeling of the changed position of
the parts, on the other. From the earliest ancestors of ours
which had feet, down to the present day, the movement of
the feet must always have accompanied the will to move
them ; and here, if anywhere, habit's consequences ought
to be found.! The process of the willing ought, then, to pour
into the process of feeling the command effected, and ought
to awaken that feeling in a maximal degree provided no
other positively contradictory sensation come in at the same
time. In most of us, when the will fails of its efi'ect there
is a contradictory sensation. We discern a resistance or
the unchanged position of the limb. But neither in anaes-
thesia nor in amputation can there be any contradictory
sensation in the foot to correct us ; so imagination has all
the force of fact.
* Pflliger's Arcbiv, xxxvii. 1.
f Not all patients have this additional illusion.
X I ought to say that in almost all cases the volition is followed b^
actual contraction of muscles in the utump.
TEB PERCEPTION OF THINGS. 107
•APPEBCEPTION.'
In Germany since Herbart's time Psychology hasalwayi
had a great deal to say about a process called Apperception.*
The incoming ideas or sensations are said to be * apper-
ceived ' by * masses ' of ideas already in the mind. It is plain
that the process we have been describing as perception isj
at this rate, an apperceptive process. So are all recogni-
tion, classing, and naming ; and passing beyond these sim-
plest suggestions, all farther thoughts about our percepts are
apperceptive processes as well. I have myself not used the
word apperception because it has carried very different mean-
ings in the history of philosophy,! and * psychic reaction,*
* interpretation,' * conception,' * assimilation,' * elaboration,'
or simply * thought,' are perfect synonyms for its Herbartian
meaning, widely taken. It is, moreover, hardly worth while
to pretend to analyze the so-called apperceptive perform-
ances beyond the first or perceptive stage, because their varia-
tions and degrees are literally innumerable. * Apperception '
is a name for the sum-total of the effects of what we have
studied as association; and it is obvious that the things
which a given experience will suggest to a man depend on
what Mr. Lewes calls his entire psychostatical conditions,
his nature and stock of ideas, or, in other words, his charac-
ter, habits, memory, education, previous experience, and
momentary mood. We gain no insight into what really oc-
curs either in the mind or in the brain by calling all these
things the * apperceiving mass,' though of course this may
upon occasion be convenient. On the whole I am inclined
to think Mr. Lewes's term of * assimilation ' the most fruit-
ful one yet used.if
Professor H. Steinthal has analyzed apperceptive pro-
cesses with a sort of detail which is simply burdensome. §
* Cf. Herbart, Psychol, als. Wissenschaft, § 125.
t Compare the historical reviews by K. Lange : Ueber Apperception
(Plauen, 1879), pp. 12-14; by Staude in Wundt's Philosophische Studien, i.
149; and by Marty in Vierteljsch. f. wiss. Phil., x. 347 ff.
X Problems, vol. i. p. 118 ff.
§ See his Einleitung in die Psychologie u. Sprachwissenschaft (1881 X
p. 166 n.
108 paroHOLOoT.
His introduction of the matter may, however, be quoted
He begins with an anecdote from a comic paper.
'* In the compartment of a railway-carriage six persons unknown to
each other sit in lively conversation. It becomes a matter of regret that
one of the company must alight at the next station. One of the others
says that he of all things prefers such a meeting with entirely unknown
persons, and that on such occasions he is accustomed neither to ask who
or what his companions may be nor to tell who or what he is. Another
Ghereupon says that he will undertake to decide this question, if they
each and all will answer him an entirely disconnected question. They
began. He drew five leaves from his note-book, wrote a question on
each, and gave one to each of his companions with the request that he
write the answer below. When the leaves were returned to him, he
turned, after reading them, without hesitation to the others, and said to
the first, * You are a man of science'; to the second, ' You are a sol
dier'; to the third, 'You are a philologer'; to the fourth, ' You are a
journalist'; to the fifth, 'You are a farmer.' All admitted that he
was right, whereupon he got out aod left the five behind. Each
wished to know what question the others had received; and behold, he
had given the same question to each. It ran thus :
" ' What being destroys what it has itself brought forth ?
"To this the naturalist had answered, 'vital force'; the soldier,
war'; the philologist, 'Kronos'; the publicist, 'revolution'; the
farmer, 'a boar'. This anecdote, methinks, if not true, is at least
splendidly well invented. Its narrator makes the journalist go on to
say : ' Therein consists the joke. Each one answers the first thing that
occurs to him,* and that is whatever is most newly related to his pur-
suit in life. Every question is a hole-drilling experiment, and the an-
swer is an opening through which one sees into our interiors.' ... So
do we all. We are all able to recognize the clergyman, the soldier, the
scholar, the business man, not only by the cut of their garments and
the attitude of their body, but by what they say and how they express
it. We guess the place in life of men by the interest which they show
and the way in which they show it, by the objects of which they speak,
by the point of view from which they regard things, judge them, conceive
them, in short by their mode of apperceiving , . . .
"Every man has one group of ideas which relate to his own person
and interests, and another which is connected with society. Each ha^:,
his group of ideas about plants, religion, law, art, etc., and more
especially about the rose, epic poetry, sermons free trade, and the like
Thus the mental content of every individual, even of the uneducated
* One of my colleagues, asking himself the question after reading the
fcnecdote, tells me that he replied * Harvard College/ the faculty of that body
having voted, a few days previously, to keep back the degrees of membeio
^ the ffraduatine clais who might be disorderly on class-day night. W. J
THS PERCEPTION OF THINOS. 100
and of children, consists of masses or circles of knowledge of whlck
each lies within some larger circle, alongside of others similarly in-
cluded, and of which each includes smaller circles within itself. . . .
The perception of a thing like a horse ... is a process between the
present horse's picture before our eyes, on the one hand, and those fused
or interwoven pictures and ideas of all the horses we have ever seen, on
the other; ... a process between two factors or momenta, of which
one existed before the process and was an old possession of the mind
(the group of ideas, or concept, namely), whilst the other is but just
presented to the mind, and is the immediately supervening factor (the
sense-impression). The former apperceives the latter; the latter is
apperceived by the former. Out of their combination an apperception-
product arises: the knowledge of the perceived being as a horse. The
earlier factor is relatively to the later one active and a priori ; the super-
vening factor is given, a posteriori^ passive. . . . We may then define
Apperception as the movement of two masses of consciousness (Vorstel-
lungsmassen) against each other so as to produce a cognition.
" Ih!^ a priori factor we called active, i\\Q a posteriori factor passive,
but this is only relatively true. . . . Although the a priori moment
commonly shows itself to be the more powerful, apperception- processes
can perfectly well occur in which the new observation transforms or en-
riches the apperceiving group of ideas. A child who hitherto has seen
none but four-cornered tables apperceives a round one as a table; but
by this the apperceiving mass ('table') is enriched. To his previous
knowledge of tables comes this new feature that they need not be four-
cornered, but may be round. In the history of science it' has happened
often enough that some discovery, at the same time that it was apper-
ceived, i.e. brought into connection with the system of our knowledge,
transformed the whole system. In principle, however, we must maintain
that, although either factor is both active and passive, the a 'priori factor
is almost always the more active of the two." *
This account of Steinthal's brings out very clearly the
difference between our psychological conceptions and what are
called concepts in logic. In logic a concept is unalterable ; but
what are popularly called our * conceptions of things ' alter
by being used. The aim of * Science ' is to attain concep-
tions so adequate and exact that we shall never need to
change them. There is an everlasting struggle in every
mind between the tendency to keep unchanged, and the
tendency to renovate, its ideas. Our education is a cease-
less compromise between the conservative and the pro-
gressive factors. Every new experience must be disposed
• Op. ctt. pp. 166-171.
110 P8Y0H0L00Y.
of under some old head. The great point is to find the head
which has to be least altered to take it in. Certain Polyne-
sian natives, seeing horses for the first time, called them
pigs, that being the nearest head. My child of two played
for a week with the first orange that was given him, calling
it a *ball.' He called the first whole eggs he saw * potatoes,'
having been accustomed to see his ' eggs ' broken into a
glass, and his potatoes without the skin. A folding pocket-
corkscrew he unhesitatingly called * bad-scissors.' Hardly
any one of us can make new heads easily when fresh expe-
riences come. Most of us grow more and more enslaved to
the stock conceptions with which we have once become
familiar, and less and less capable of assimilating impres-
sions in any but the old ways. Old-fogyism, in short, is the
inevitable terminus to which life sweeps us on. Objects
which violate our established habits of * apperception ' are
simply not taken account of at all ; or, if on some occasion
we are forced by dint of argument to admit their existence,
twenty-four hours later the admission is as if it were not,
and every trace of the unassimilable truth has vanished
from our thought. Genius, in truth, means little more than
the faculty of perceiving in an unhabitual way.
On the other hand, nothing is more congenial, from
babyhood to the end of life, than to be able to assimilate
the new to the old, to meet each threatening violator or
burster of our well-known series of concepts, as it comes
in, see through its unwontedness, and ticket it off as an old
friend in disguise. This victorious assimilation of the new
is in fact the type of all intellectual pleasure. The lust for
it is curiosity. The relation of the new to the old, before
the assimilation is performed, is wonder. We feel neither
curiosity nor wonder concerning things so far beyond us
that we have no concepts to refer them to or standards by
which to measure them.^ The Fuegians, in Darwin's voy-
* The great maxim in pedagogy is to knit every new piece of knowl-
edge on to a pre-existing curiosity — i.e., to assimilate its matter in some
way to what is already known. Hence the advantage of " comparing all
that is far off and foreign to something that is near home, of making the
unknown plain by the example of the known, and of connecting all the
Instruction with the personal experience of the pupil. ... If the teacher \%
THE PERCEPTION OF THINGS. Ill
age, wondered at the small boats, but took the big ship as
a * matter of course.' Only what we partly know already
inspires us with a desire to know more. The more elabo-
rate textile fabrics, the vaster works in metal, to most of
us are like the air, the water, and the ground, absolute ex-
istences which awaken no ideas. It is a matter of course
that an engraving or a copper-plate inscription should pos-
sess that degree of beauty. But if we are shown a un-
drawing of equal perfection, our personal sympathy with
the difficulty of the task makes us immediately wonder at
the skill. The old lady admiring the Academician's picture,
says to him : " And is it really all done hy hand .^"
IS PERCEPTION UNCONSCIOUS INFERENCE?
A widely-spread opinion (which has been held by such
men as Schopenhauer, Spencer, Hartmann, Wundt, Helm-
holtz, and lately interestingly pleaded for by M. Binet *)
will have it that perception should he called a sort of reasoning
operation^ more or less unconsciously and automatically per-
formed. The question seems at first a verbal one, depend-
ing on how broadly the term reasoning is to be taken. If,
every time a present sign suggests an absent reality to our
mind, we make an inference ; and if every time we make an
inference we reason ; then perception is indubitably reason-
ing. Only one sees no room in it for any unconscious part.
Both associates, the present sign and the contiguous things
which it suggests, are above-board, and no intermediary
to explain the distance of the sun from the earth, let him ask ... 'If any-
one there in the sun fired off a cannon straight at you, what should you
do?' 'Get out of the way ' would be the answer. 'No need of that,'
the teacher might reply. * You may quietly go to sleep in your room,
and get up again, you may wait till your confirmation-day, you may learn
a trade, and grow as old as I 2ixn.,—then only will the cannon-ball be get-
ting near, then you may jump to one side! See, so great as that is the sun's
distance!'" (K. Lange, Ueber Apperception, 1879, p. 76— a charming
though prolix little work.)
* A. Schopenhauer, Satz vom Grunde, chap. iv. H. Spencer, Psychol.,
part VI. chaps, ix, x. E. v. Hartmann, Phil, of the Unconscious (B),
chaps. VII, VIII. W. Wundt, Beitrage, pp. 422 If.; Vorlesungen, iv, xiii.
H. Helmholtz, Physiol. Optik, pp. 480, 447. A. Binet, Psychol, du Rai-
Bonnement, chaps, in, v. Wundt and Helmholtz have more recently
•recanted.' See above, vol i. p. 169 note.
Ill PSYCHOLOGY.
ideas are required. Most of those who have upheld the
thesis in question have, however, made a more complex
supposition. What they have meant is that perception is
a mediate inference, and that the middle term is unconscious.
When the sensation which I have called * this ' (p. 83, supra)
is felt, they think that some process like the following runs
through the mind :
' This ' is M ;
but M is A ;
therefore * this * is A.*
Now there seem no good grounds for supposing this
additional wheelwork in the mind. The classification of
* this ' as M is itself an act of perception, and should, if all
perception were inference, require a still earlier syllogism for
its performance, and so backwards in infinitum. The only
extrication from this coil would be to represent the process
in altered guise, thus :
*This' is like those;
Those are A ;
Therefore * this ' is A.
The major premise here involves no association by conti-
guity, no naming of those as M, but only a suggestion of
unnamed similar images, a recall of analogous past sensa-
tions with which the characters that make up A were habit-
ually conjoined. But here again, what grounds of fact are
there for admitting this recall ? We are quite unconscious
of any such images of the past. And the conception of all
the forms of association as resultants of the elementary fact
of habit-worn paths in the brain makes such images entirely
superfluous for explaining the phenomena in point. Since
the brain-process of ' this,' the sign of A, has repeatedly
been aroused in company with the process of the full object
A, direct paths of irradiation from the one to the other must
be already established. And although roundabout paths
may also be possible, as from *this' to 'those,' and then
* When not all M, but only some M, is A, when, in other words, M is
' undistributed ' the conclusion is liable to error. Illusions would thus be
logical fallacies, if true perceptions were valid syllogisms. They would
dr»w false conclusions from undistributed middle terms.
THE PERCEPTION OF THINGS. 113
from 'those ' to * A' (paths which would lead to practically
the same conclusion as the straighter ones), yet there is no
ground whatever for assuming them to be traversed now,
especially since appearances point the other way. In
explicit reasoning, such paths are doubtless traversed , in
perception they are in all probability closed. So far, then,
from perception being a species of reasoning properly so
called, both it and reasoning are co-ordinate varieties of that
deeper sort of process known psychologically as the asso-
ciation of ideas, and physiologically as the law of habit in
the brain. To call perception unconscious reasoning is thus
either a useless metaphor ^ or a positively misleading confusion
between two different things.
One more point and we may leave the subject of Per-
ception. Sir Wm, Hamilton thought that he had discovered a
* great law ' which had been wholly overlooked by psycholo-
gists, and which, * simple and universal,' is this : " Knowl-
edge and Feeling, — Perception and Sensation, though al-
ways coexistent, are always in the inverse ratio of each
other." Hamilton wrote as if perception and sensation
were two coexistent elements entering into a single state
of consciousness. Spencer refines upon him by contending
that they are two mutually exclusive states of conscious-
ness, not two elements of a single state. If sensation be
taken, as both Hamilton and Spencer mainly take it in this
discussion, to mean the feeling of pleasure or pain, there is
no doubt that the law, however expressed, is true ; and that
the mind which is strongly conscious of the pleasantness or
painfulness of an experience is ipso facto less fitted to
observe and analyze its outward cause.* Apart from pleas-
ure and pain, however, the law seems but a corollary of the
fact that the more concentrated a state of consciousness is,
the more vivid it is. When feeling a color, or listening to
a tone per se, we get it more intensely, notice it better, than
when we are aware of it merely as one among many other
properties of a total object. The more diffused cerebral
excitement of the perceptive state is probably incompatible
* See Spencer, Psychol. , ii. p. 250, note, for a physiological hypothesis
to account for this fact.
114 PSTOHOLOOT:
with quite as strong an excitement of separate parts as
the sensational state comports. So we come back here to
our own earlier discrimination between the perceptive and
the sensational processes, and to the examples which we
gave on pp. 80, 81.*
HALLUCINATIONS.
Between normal perception and illusion we have seen
that there is no break, the process being identically the same
in both. The last illusions we considered might fairly be
called hallucinations. We must now consider the false
perceptions more commonly called by that name.f In or-
* Here is another good example, taken from Helmholtz's Optics, p. 435:
*'The sight of a man walking is a familiar spectacle to us. We perceive
it as a connected whole, and at most notice the most striking of its pecu-
liarities. Strong attention is required, and a special choice of the point of
view, in order to feel the perpendicular and lateral oscillations of such a
walking figure. We must choose fitting points or lines in the background
with which to compare the positions of its head. But if a distant walking
man be looked at through an astronomical telescope (which inverts the
object), what a singular hopping and rocking appearance he presents ! No
difficulty now in seeing the body's oscillations, and many other details of
the gait. . . . But, on the other hand, its total character, whether light or
clumsy, dignified or graceful, is harder to perceive than in the upright po-
sition."
f Illusions and hallucinations must both be distinguished from delusions.
A delusion is a false opinion about a matter of fact, which need not neces-
sarily involve, though it often does involve, false perceptions of sensible
things. We may, for example, have religious delusions, medical delusions,
delusions about our own importance, about other peoples' characters, etc.,
ad libitum. The delusions of the insane are apt to affect certain typical
forms, often very hard to explain. But in many cases they are certainly
theories which the patients invent to account for their abnormal bodily
sensations. In other cases they are due to hallucinations of hearing and of
sight. Dr. Clouston (Clinical Lectures on Mental Disease, lecture iii ad
fin.) gives the following special delusions as having been found in about
a hundred melancholy female patients who were afflicted in this way.
There were delusions of
general persecution; being destitute;
general suspicion; being followed by the police;
being poisoned; being very wicked;
being killed; impending death;
being conspired against; impending calamity;
being defrauded; the soul being lost;
being preached against Id church; having no stomach;
being pregnant; having no inside;
THE PERGBPTION OF THINGS, 115
dinary parlance hallucination is held to differ from illusion in
that, whilst there is an object really there in illusion, inhcdlu-^
dnation there is no objective stimulus at aU. We shall presently
see that this supposed absence of objective stimulus in hal^
lucination is a mistake, and that hallucinations are often
only extremes of the perception process, in which the secon-
dary cerebral reaction is out of all normal proportion to the
peripheral stimulus which occasions the activity. Hallu-
cinations usually appear abruptly and have the character of
being forced upon the subject. But they possess various
degrees of apparent objectivity. One mistake in limine must
be guarded against. They are often talked of as mental
images projected outwards by mistake. But where an hallu-
cination is complete, it is much more than a mental image.
An JiaRucimxtion is a strictly sensational form of consciousnesSj
as good and true a sensation as if there were a real object there.
The object happens not to be there, that is all.
The milder degrees of hallucination have been desig-
nated as pseudo-hallmylnations. Pseudo-hallucinations and
hallucinations have been sharply distinguished from each
having a bone In the throat; having neither stomach nor biains;
having lost much money; being covered with vermin ;
being unfit to live; letters being written about her;
that she will not recover; property being stolen;
that she is to be murdered; her children being killed;
that she is to be boiled alive; having committed theft;
that she is to be staived; the legs being made of glas>;
that the flesh is boiling; having horns on the head;
that the head is severed from the being chloroformed;
body; having committed murder;
that children are burning; fear of being hanged;
that murders take place around; being called names by person ;
that it is wrong to take food; being acted on by spirits;
being in hell; being a man;
being tempted of the devil; the body being transformed;
being possessed of the devil; insects coming from the bod/
having committed an unpardon- rape being practised on her:
able sin; having a venereal disease;
unseen agencies working; being a fish;
her own identity; being dead;
being on fire; having committed 'suicide of the soi il .
116 PSYCHOLOGY.
other only within a few years. Dr. Kandinsty writes of
their difference as follows :
^ ' In carelessly questioning a patient we may confound his pseudo-
hallucinatory perceptions with hallucinations. But to the unconfused
consciousness of the patient himself, even though he be imbecile, the
identification of the two phenomena is impossible, at least in the sphere
of vision. At the moment of having a pseudo-hallucination of sight^
the patient feels himself in an entirely different relation to this subjec-
tive sensible appearance, from that in which he finds himself whilst
subject to a true visual hallucination. The latter is reality itself ; the
former, on the contrary, remains always a subjective phenomenon
which the individual commonly regards either as sent to him as a sign
of God's grace, or as artificially induced by his secret persecutors . . .
If he knows by his own expei'ience what a genuine hallucination is, it is
quite impossible for him to mistake the pseudo-hallucination for it. . . .
A concrete example will make the difference clear :
"Dr. N". L. . . . heard one day suddenly amongst the voices of his
persecutors (' coming from a hollow space in the midst of the wall ') a
rather loud voice impressively saying to him ; ' Change your national
allegiance.' Understanding this to mean that his only hope consisted
in ceasing to be subject to the Czar of Kussia, he reflected a moment
what allegiance would be better, and resolved to become an English sub-
ject. At the same moment he saw a pseudo-hallucinatory lion of
natural size, which appeared and quickly laid its fore-paws on his
shoulders. He had a lively feeling of these paws as a tolerably painful
local pressure (complete hallucination of touch). Then the same voice
from the wall said : ' Now you have a lion — now you will rule,' where-
upon the patient recollected that the lion was the national emblem of
England. The lion appeared to L. very distinct and vivid, but he never-
theless remained conscious, as he afterwards expressed it, that he saw the
animal, not with his bodily but with his mental eyes. (After his re-
covery he called analogous apparitions by the name of ' expressive-plastic
ideas.') Accordingly he felt no terror, even though he felt the contact of
the claws. . . . Had the lion been a complete hallucination, the patient,
as he himself remarked after recovery, would have felt great fear, and
very likely screamed or taken to flight. Had it been a simple image of
the fancy he would not have connected it with the voices, of whose ob-
jective reality he was at the time quite convinced." *
From ordinary images of memory and fancy, pseudo-
hallucinations differ in being much more vivid, minute, de-
*V. Kandinsky: Kritische u. Klinische Betrachtungeu imGebleted
BinnestAuschungen (1885), p. 42.
THE PERCEPTION OF THINGS. 117
tailed, steady, abrupt, and spontaneous, in the sense that
all feeling of our own activity in producing them is lacking.
Dr. Kandiusky had a patient who, after taking opium or
haschisch, had abundant pseudo-hallucinations and hallu-
cinations. As he also had strong visualizing power and
was an educated physician, the three sorts of phenomena
could be easily compared. Although projected outwards
{usually not farther than the limit of distinctest vision, a
foot or so) the pseudo- hallucinations Icwked the character of
objective reality which the hallucinations possessed, but,'
unlike the pictures of imagination, it was almost impossible
to produce them at will. Most of the * voices ' which people
hear (whether they give rise to delusions or not) are pseudo-
hallucinations. They are described as * inner' voices, al-
though their character is entirely unlike the inner speech
of the subject with himself. I know two persons who hear
such inner voices making unforeseen remarks whenever they
grow quiet and listen for them. They are a very common
incident of delusional insanity, and at last grow into vivid
hallucinations. The latter are comparatively frequent oc-
currences in sporadic form ; and certain individuals are
liable to have them often. From the results of the * Census
of Hallucinations,' which was begun by Edmund Gurney, it
would appear that, roughly speaking, one person at least
in every ten is likely to have had a vivid hallucination at
some time in his life.* The following cases from healthy
people will give an idea of what these hallucinations are :
"When a girl of eighteen, I was one evening engaged in a very
painful discussion with an elderly person. My distress was so great
that I took up a thick ivory knitting-needle that was lying on the man-
telpiece of the parlor and broke it into small pieces as I talked. In the
midst of the discussion 1 was very wishful to know the opinion of a
brother with whom I had an unusually close relationship. I turned
round and saw him sitting at the further side of a centre- table, with his
arms folded (an unusual position with him), but, to my dismay, I per-
* See Proceedings of Soc. for Psych. Research, Dec. 1889, pp. 7, 188L
The International Congress for Experimental Psychology has now cAuacge
of the Census, and the present writer is its agent for America.
118 PBTOHOLOOT.
oeired from the sarcastic expression of his mouth that he was not in
sympathy with me, was not 'taking my side,' as I should then liave
expressed it. The surprise cooled me, and the discussion was dropped.
"Some minutes after, having occasion to speak to my brother, I
turned towards him, but he was gone. I inquired when he left the
room, and was told that he had not been in it, which I did not believe,
thinking that he had come in for a minute and had gone out without
being noticed. About an hour and a half afterwards he appeared, and
convinced me, with some trouble, that he had never been near th»
house that evening. He is still alive and well."
Here is another case :
"One night in March 1873 or '74, I cannot recollect which year,
I was attending on the sick-bed of my mother. About eight o'clock in
the evening I went into the dining room to fix a cup of tea, and on turn-
ing from the sideboard to the table, on the other side of the table before
the fire, which was burning brightly, as was also the gas, I saw standing
with his hand clasped to his side in true military fashion a soldier of
about thirty years of age, with dark, piercing eyes looking directly into
mine. He wore a small cap with standing feather ; his costume was
also of a soldierly style. He did not strike me as being a spirit, ghost,
or anything uncanny, only a living man ; but after gazing for fully a
minute I realized that it was nothing of earth, for he neither moved
his eyes nor his body, and in looking closely I could see the fire beyond.
I was of course startled, and yet did not run out of the room. I fell
stunned. I walked out rapidly, however, and turning to the servant
in the hall asked her if she saw anything. She said not. I went into
my mother's room and remained talking for about an hour, but never
mentioned the above subject for fear of exciting her, and finally forgot
it altogether, returning to the dining-room, still in forgetfulness of
what had occurred, but repeating, as above, the turning from sideboard
to table in act of preparing more tea. I looked casually towards the
fire, and there I saw the soldier again. This time I was entirely alarmed,
and fled from the room in haste. I called to my father, but when he
came he saw nothing."
Sometimes more than one sense is affected. The fol-
lowing is a case :
" In response to your request to write out my experience of Oct. 30,
1886, I will inflict on you a letter.
" On the day above mentioned, Oct. 30, 1886, I was in ,
where I was teaching. I had performed my regular routine work for
the day, and was sitting in my room working out trigonometrical for-
THE PERCEPTION OF THINGS. 119
mulsB. I was expecting every day to hear of the confinement of my wife,
and naturally my thoughts for some time had been more or less with
her. She was, by the way, in B , some fifty miles from me.
" At the time, however, neither she nor the expected event was in my
mind ; as I said, I was working out trigonometrical formulab, and I had
been working on trigonometry the entire evening. About eleven
o'clock, as I sat there buried in sines, cosines, tangents, cotangents,
aecants, and cosecants, I felt very distinctly upon my left shoulder 9
touch, and a slight shake, as if somebody had tried to attract my at-
tention by other means and had failed. Without rising I turned my
head, and there between me and the door stood my wife, dressed exactly
as I last saw her, some five weeks before. As I turned she said : ' It
is a little Herman ; he has come.' Something more was said, but this
is the only sentence i can recall. To make sure that I was not asleep
and dreaming, I rose from the chair, pinched myself and walked toward
the figure, which disappeared immediately as I rose. I can give no in-
formation as to the length of time occupied by this episode, but I know
I was awake, in my usual good health. The touch was very distinct,
the figure was absolutely perfect, stood about three feet from the door,
which was closed, and had not been opened during the evening. The
sound of the voice was unmistakable, and I should have recognized it as
my wife's voice even if I had not turned and had not seen the figure
at all. The tone was conversational, just as if she would have said
the same words had she been actually standing there.
*' In regard to myself, I would say, as I have already intimated, I was
in my usual good health ; I had not been sick before, nor was I after
the occurrence, not so much as a headache having afflicted me.
" Shortly after the experience above described, I retired for the night
and, as I usually do, slept quietly until morning. I did not speculate
particularly about the strange appearance of the night before, and
though I thought of it some, I did not tell anybody. The following
morning I rose, not conscious of having dreamed anything, but I was
very firmly impressed with the idea that there was something for me at
the telegraph-office. I tried to throw off the impression, for so far as I
knew there was no reason for it. Having nothing to do, I went out for
a walk ; and to help throw off the impression above noted, I walked
away from the telegraph-office. As T proceeded, however, the impres-
sion became a conviction, and I actually turned about and went to the
very place I had resolved not to visit, the telegraph-office. The first
person I saw on arriving at said office was the telegraph-operator, who
being on terms of intimacy with me, remarked : ' Hello, papa, I've got
a telegram for you.' The telegram announced the birth of a boy,
weighing nine pounds, and that all were doing well. Now, then, I have
no theory at all about the events narrated above ; I never had any such
experience before nor since ; I am no believer in spiritualism, am not in
the least superstitious, know very little about ' thought-transference/
120 PSYCHOLOGY,
* unconscious cerebration/ etc., etc., but I am absolutely certain about
what I have tried to relate.
" In regard to the remark which I heard, ' It is a little Herman,' etc.,
I would add that we had previously decided to call the child, if a boy,
Herman— my own name, by the way."*
The hallucination sometimes carries a change cf the
general consciousness with it, so as to appear mor« like a
sudden lapse into a dream. The following case was given
me by a man of 43, who hac' never anything resembling it
before :
*' While sitting at my desk this a. m. reading a circular of the Loyal
Legion a very curious thing happened to me, such as I have never ex-
perienced. It was perfectly real, so real that it took some minutes to
recover from. It seems to me like a direct intromission into some other
world. I never had anything approaching it before save when dream-
ing at night. I was wide awake, of course. But this was the feeling. I
had only just sat down and become interested in the circular, when I
seemed to lose myself for a minute and then found myself in the top
story of a high building very white and shining and clean, with a
noble window immediately at the right of where I sat. Through this
window I looked out upon a marvellous reach of landscape entirely new.
I never had before such a sense of infinity in nature, such superb
stretches of light and color and clean7iess. T know that for the space
of three minutes I was entirely lost, for when I began to come to, so to
speak, — sitting in that other world, I debated for three or four minutes
more as to which was dream and which was reality. Sitting there I got
a faint sense of C [the town in which the writer was], away off
and dim at first. Then I remember thinking ' Why, I used to live in
C ; perhaps I am going back.' Slowly C. . . . did come back, and
I found myself at my desk again. For a few minutes the process of
determining where I was was very funny. But the whole experience
was perfectly delightful, there was such a sense of brilliancy and
clearness and lightness about it. I suppose it lasted in all about seven
minutes or ten minutes."
The hallucinations of fever-delirium are a mixture of
pseudo-hallucination, true hallucination, and illusion.
Those of opium, hasheesh, and belladonna resemble them
*This case is of the class which Mr. Myers terms 'veridical.' In c
subsequent letter the writer informs me that his vision occurred some flv«
houn brfore the child was born.
THE PERCEPTION OF THINGS. 121
in this respect. The following vivid account of a fit of
hasheesh-delirium has been given me by a friend :
" I was reading a newspaper, and the indication of the approaching
delirium was an inability to keep my mind fixed on the narrative. Di-
rectly I lay down upon a sofa there appeared before my eyes several
rows of human hands, which oscillated for a moment, revolved and then
changed to spoons. The same motions were repeated, the objects chang-
ing to wheels, tin soldiers, lamp-posts, brooms, and countless other
absurdities. This stage lasted about ten minutes, and during that
time it is safe to say that I saw at least a thousand different objects.
These whirling images did not appear like the realities of life, but had
the character of the secondary images seen in the eye after looking at
some brightly-illuminated object. A mere suggestion from the person
who was with me in the room was sufficient to call up an image of the
thing suggested, while without suggestion there appeared all the com-
mon objects of life and many unreal monstrosities, which it is abso-
lutely impossible to describe, and which seemed to be creations of the
brain.
" The character of the symptoms changed rapidly. A sort of wave
seemed to pass over me, and I became aware of the fact that my pulse
was beating rapidly. I took out my watch, and by exercising consider-
able will-power managed to time the heart-beats, 135 to the minute.
*' I could feel each pulsation through my whole system, and a curi-
ous twitching commenced, which no effort of the mind could stop.
'* There were moments of apparent lucidity, when it seemed as if I
could see within myself, and watch the pumping of my heart. A
strange fear came over me, a certainty that I should never recover from
the effects of the opiate, which was as quickly followed by a feeling of
great interest in the experiment, a certainty that the experience was
the most novel and exciting that I had ever been through.
' ' My mind was in an exceedingly impressionable state. Any place
thought of or suggested appeared with all the distinctness of the reality.
I thought of the Giant's Causeway in Staffa, and instantly I stood
within the portals of Fingal's Cave. Great basaltic columns rose on all
sides, while huge waves rolled through the chasm and broke in silence
upon the rocky shore. Suddenly there was a roar and blast of sound,
and the word ' Ishmaral ' was echoing up the cave. At the enunciation
of this remarkable word the great columns of basalt changed into whirl-
ing clothes pins and I laughed aloud at the absurdity.
" (I may here state that the word ' Ishmaral' seemed to haunt my
other hallucinations, for I remember that I heard it frequently there-
after.) I next enjoyed a sort of metempsychosis. Any animal or
thing that I thought of could be made the being which held my mind.
I thought of a fox, and instantly I was transformed into that animal. 1
oould distinctly feel myself a fox, could see my long ears and bushy
122 PSYCHOLOGY.
tail, and by a sort of introvision felt that my complete anatomy was
that of a fox. Suddenly the point of vision changed. My eyes seemed
to be located at the back of my mouth ; I looked out between the parted
lips, saw the two rows of pointed teeth, and, closing my mouth with a
snap, saw — nothing.
" I was next transformed into a bombshell, felt my size, weight, and
thickness, and experienced the sensation of being shot up out of a giant
mortar, looking down upon the earth, bursting and falling back in a
shower of iron fragments.
" Into countless other objects was I transformed, many of them so
absurd that I am unable to conceive what suggested them. For ex-
ample, I was a little china doll, deep down in a bottle of olive oil, next
moment a stick of twisted candy, then a skeleton inclosed in a whirl-
ing coffin, and so on ad infinitum.
" Towards the end of the delirium the whirling images appeared
again, and I was haunted by a singular creation of the brain, which re-
appeared every few moments. It was an image of a double-faced doll,
with a cylindrical body running down to a point like a peg-top.
" It was always the same, having a sort of crown on its head, and
painted in two colors, green and brown, on a background of blue. The
expression of the Janus-like profiles was always the same, as were the
adornments of the body. After recovering from the effects of the
drug I could not picture to myself exactly how this singular monstros-
ity appeared, but in subsequent experiences I was always visited by
this phantom, and always recognized every detail of its composition.
It was like visiting some long-forgotten spot and seeing some sight that
had faded from the memory, but which appeared perfectly familiar as
soon as looked upon.
" The effects of the drug lasted about an hour and a half, leaving
me a trifle tipsy and dizzy ; but after a ten-hour sleep I was myself
again, save for a slight inability to keep my mind fixed on any piece of
work for any length of time, which remained with me during most of
the next day.''
THE NEUBAIi PBOCESS IN HAIiLUCINATION.
Examples of these singular perversions of perception
might be multiplied indefinitely, but I have no more space.
Let us turn to the question of what the physiological pro-
cess may be to which they are due. It must, of course,
consist of an excitement from within of those centres which
are active in normal perception, identical in kind and de-
gree with that which real external objects are usually
needed to induce. The particular process which cur-
THE PERCEPTION OF THINGS, 1V3
rents from the sense-organs arouse would seem under
normal circumstances to be arousable in no other way. On
p. 72 if. above, we saw that the centres aroused by incom-
ing peripheral currents are probably identical with the
centres used in mere imagination ; and that the vividness
of the sensational kind of consciousness is probably cor-
related with a discrete degree of intensity in the process
therein aroused. Referring the reader back to that pas-
sage and to what was more lately said on p. 103 ff., I now
proceed to complete my theory of the perceptive process
by an analysis of what may most probably be believed to
take place in hallucination strictly so called.
We have seen (p. 75) that the free discharge of cells
into each other through associative paths is a likely reason
why the maximum intensity of function is not reached
when the cells are excited by their neighbors in the cortex.
At the end of Chapter XXV we shall return to this concep-
tion, and whilst making it still more precise, use it for ex-
plaining certain phenomena connected with the will. The
idea is that the leakage forward along these paths is too
rapid for the inner tension in any centre to accumulate to
the maximal explosion-point, unless the exciting currents
are greater than those which the various portions of the
cortex supply to each other. Currents from the periphery
are (as it seems) the only currents whose energy can van-
quish the supra-ideational resistance (so to call it) of the
cells, and cause the peculiarly intense sort of disintegra-
tion with which the sensational quality is linked. If, how-
ever , the leakage forward were to stop, the tension inside cer-
tain cells might reach the explosion-point, even though the
influence which excited them came only from neighboring
cortical parts. Let an empty pail with a leak in its bottom,
tipped up against a support so that if it ever became full
of water it would upset, represent the resting condition of
the centre for a certain sort of feeling. Let water poured
into it stand for the currents which are its natural stimulus ;
then the hole in its bottom will, of course, represent the
* paths * by which it transmits its excitement to other asso-
ciated cells. Now let two other vessels have the functior
I
124 PsroHOLOGr.
of supplying it with water. One of these vessels stands
for the neighboring cortical cells, and can pour in hardly
any more water than goes out by the leak. The pail conse-
sequently never upsets in consequence of the supply from
this source. A current of water passes through it and does
work elsewhere, but in the pail itself nothing but what
stands for ideatioiial activity is aroused. The other vessel,
however, stands for the peripheral sense-organs, and sup-
plies a stream of water so copious that the pail promptly
fills up in spite of the leak, and presently upsets ; in other
words, sensational activity is aroused. But it is obvious that
if the leak were plugged, the slower stream of supply
would also end by upsetting the pail.
To apply this to the brain and to thought, if we take a
series of processes ABODE, associated together in that
order, and suppose that the current through them is very
fluent, there will be little intensity anywhere until, perhaps,
a pause occurs at E. But the moment the current is blocked
anywhere, say between C and D, the process in C must
grow more intense, and might even be conceived to explode
so as to produce a sensation in the mind instead of an idea.
It would seem that some hallucinations are best to be
explained in this way. We have in fact a regular series of
facts which can all be formulated under the single law that ^Ae
substantive strength of a state of consciousness hears an inverse
'proportion to its suggestiveness. It is the halting-places of
our thought which are occupied with distinct imagery.
Most of the words we utter have no time to awaken images
at all ; they simply awaken the following words. But when
the sentence stops, an image dwells for awhile before the
mental eye (see Vol. I. p. 243). Again, whenever the asso-
ciative processes are reduced and impeded by the approach
of unconsciousness, as in falling asleep, or growing faint, or
becoming narcotized, we find a concomitant increase in the
intensity of whatever partial consciousness may survive. In
some people what M. Maury has called * hypnagogic ' hal-
lucinations * are the regular concomitant of the process of
- -^Tl-i^ — «
*Le Sommeil et les R6ves (1865), chaps, m, it
THE PERCEPTION OF THINGS. 126
falling asleep. Trains of faces, landscapes, etc., pass before
the mental eye, first as fancies, then as pseudo-hallucina-
tions, finally as full-fledged hallucinations forming dreams.
If we regard association-paths as paths of drainage, then the
shutting off of one after another of them as the encroaching
cerebral paralysis advances ought to act like the plugging
ol the hole in the bottom of the pail, and make the activity
more intense in those systems of cells that retain any
activity at all. The level rises because the currents are
not drained away, until at last the full sensational explosion
may occur.
The usual explanation of hypnagogic hallucinations is
that they are ideas deprived of their ordinary reductives. In
somnolescence, sensations being extinct, the mind, it is said,
then having no stronger things to compare its ideas with,
ascribes to these the fulness of reality. At ordinary times
the objects of our imagination are reduced to the status of
subjective facts by the ever-present contrast of our sensa-
tions with them. Eliminate the sensations, however, this
view supposes, and the * images ' are forthwith * projected '
into the outer world and appear as realities. Thus is the
illusion of dreams also explained. This, indeed, after a
fashion gives an account of the facts.* And yet it certainly
fails to explain the extraordinary vivacity and completeness
of so many of our dream-fantasms. The process of ' imagin-
ing ' must (in these cases at least f ) be not merely relatively,
but absolutely and in itself more intense than at other
times. The fact is, it is not a process of imagining, but a
genuine sensational process ; and the theory in question is
therefore false ^s far as that point is concerned.
Dr. Hughlinecs Jackson's explanation of the epileptic
seizure is acknowledged to be masterly. It involves
* This theory of incomplete rectification of the inner images by their
usual reductives is most brilliantly stated by M. Taine in his work on
Intelligence, book ii. chap. i.
f Not, of course, in all cases, because the cells remaining active are them-
selves on the way to be overpowered by the general (unknown) condition to
which sleep is due.
126 PSYCHOLOGY.
principles exactly like those which I am bringing forward
here. The * loss of consciousness ' in epilepsy is due to the
most highly organized brain-processes being exhausted
and thrown out of gear. The less organized (more instinc-
tive) processes, ordinarily inhibited by the others, are then
exalted, so that we get as a mere consequence of relief from
the inhibition, the meaningless or maniacal action which
so often follows the attack. "^
Similarly the sybsuitus tendinorum or jerking of the
muscles which so often startles us when we are on the point
* For a full account of Jackson's theories, see his ' Croonian Lectures '
published in the Brit. Med. Journ. for 1884. Cf. also his remarks in the
Discussion of Dr. Mercier's paper on Inhibition in ' Brain,' xi. 361.
The loss of vivacity in the images in the process of waking, as well as
the gain of it in falling asleep, are both well described by M. Taine, who
writes (on Intelligence, t. 50, 58) that often in the daytime, when fatigued
and seated in a chair, it is sufficient for him to close one eye with a hand-
kerchief, when, " by degrees, the sight of the other eye becomes vague,
and it closes. All external sensations are gradually effaced, or cease, at all
events, to be remarked ; the internal images, on the other hand, feeble and
rapid during the state of complete wakefulness, become intense, distinct,
colored, steady, and lasting : there is a sort of ecstasy, accompanied by a
feeling of expansion and of comfort. Warned by frequent experience, I
know that sleep is coming on, and that I must not disturb the rising
vision ; I remain passive, and in a few minutes it is complete. Architecture,
landscapes, moving figures, pass slowly by, and sometimes remain, with
incomparable clearness of form and fulness of being ; sleep comes on, and
I know no more of the real world I am in. Many times, like M. Maury,
I have caused myself to be gently roused at different moments of this state,
and have thus been able to mark its characters. — The intense image which
seems an external object is but a more forcible continuation of the feeble
image which an instant before I recognized as internal ; some scrap of a
forest, some house, some person which I vaguely imagined on closing my
eyes, has in a minute become present to me with full bodily details, so as to
change into a complete hallucination. Then, waking up on a hand touch-
ing me, I feel the figure decay, lose color, and evaporate ; what had ap-
peared a substance is reduced to a shadow. ... In such a case, I have often
seen, for a passing moment, the image grow pale, waste away, and evapo-
rate ; sometimes, on opening the eyes, a fragment of landscape or the skirt
of a dress appears still to float over the fire-irons or on the black hearth."
This persistence of dream-objects for a few moments after the eyes are
opened seems to be no extremely rare experience. Many cases of it have
been reported to me directly. Compare Mtiller's Physiology, Baly's tr.,
p 945.
THE PERCEPTION OF THINGS. 127
of failing asleep, may be interpreted as due to tlie rise (in
certain lower motor centres) of the ordinary * tonic * tension
to the explosion-point, when the inhibition commonly ex-
erted by the higher centres falls too suddenly away.
One possible condition of hallucination then stands
revealed, whatever other conditions there may be. When
the normal paths of association between a centre and other centres
are throivn out of gear^ any axitivity which may exist in the
first centre tends to increase in intensity until finally the point
may he reached at which the last inward resistance is overcome,
and the full sensational process explodes."^ Thus it will happen
that causes of an amount of activity in brain-cells which
would ordinarily result in a weak consciousness may pro-
duce a very strong consciousness when the overflow of these
cells is stopped by the torpor of the rest of the brain. A
slight peripheral irritation, then, if it reaches the centres of
consciousness at all during sleep, will give rise to the dream
of a violent sensation. All the books about dreaming are
full of anecdotes which illustrate this. For example, M.
Maury's nose and lips are tickled with a feather while he
sleeps. He dreams he is being tortured by having a pitch-
plaster applied to his face, torn off, lacerating the skin of
nose and lips. Descartes, on being bitten by a flea, dreams
of being run through by a sword. A friend tells me, as I
write this, of his hair changing its position in his forehead
just as he * dozed off ' in his chair a few days since. In-
stantly he dreamed that some one had struck him a blow.
Examples can be quoted ad libitum, but these are enough, f
* I say the * normal ' paths, because hallucinations are not incompatible
with some paths of association being left. Some hypnotic patients will
not only have hallucinations of objects suggested to them, but will amplify
them and act out the situation. But the paths here seem excessively nar-
row, and the reflections which ought to make the hallucination incredible
do not occur to the subject's mind. In general, the narrower a train of
' ideas ' is, the vivider the consciousness is of each. Under ordinary cir-
cumstances, the entire brain probably plays a part in draining any centre
which may be ideationally active. When the drainage is reduced in any
way it probably makes the active process more intense.
t M. A. Maury gives a number: op. cit. pp. 126-8.
ia« PSYCHOLOGY.
We seem herewith to have an explanation for a certain
number of hallucinations. Whenever the normal forward
irradiation of intra-cortical excitement through association-paths
is checked^ any accidental spontaneous activity or any peripheral
stimulation {however inadequate at other times) by which a brain-
centre may be visited, sets up a process of full sensational inten-
sity therein.
In the hallucinations artificially produced in hypnotic
subjects, some degree of peripheral excitement seems usu-
ally to be required. The brain is asleep as far as its own
spontaneous thinking goes, and the words of the * magneti-
zer ' then awaken a cortical process which drafts off into
itself any currents of a related sort which may come in
from the periphery, resulting in a vivid objective percep-
tion of the suggested thing. Thus, point to a dot on a
sheet of paper, and call it * General Grant's photograph,*
and your subject will see a photograph of the General
there instead of the dot. The dot gives objectivity to the
appearance, and the suggested notion of the General gives
it form. Then magnify the dot by a lens ; double it by a
prism or by nudging the eyeball ; reflect it in a mirror ;
turn it upside down ; or wipe it out ; and the subject will
tell you that the * photograph ' has been enlarged, doubled,
reflected, turned about, or made to disappear. In M. Binet's
language, * the dot is the outward point de repere which is
needed to give objectivity to your suggestion, and without
which the latter will only produce a conception in the
subject's mind.t M. Binet has shown that such a periphe-
* M. Bluet's highly important experiments, which were first published
in vol. XVII of the Revue Philosophique (1884), are also given in full in
chapter ix of his and Fere's work on * Animal Magnetism ' in the Inter-
national Scientific Series. Where there is no dot on the paper, nor any
other visible mark, the subject's judgment about the * portrait ' would
seem to be guided by what he sees happening to the entire sheet.
f It is a difiicult thing to distinguish in a hypnotic patient between a
genuine sensorial hallucination of something suggested and a conception
of it merely, coupled with belief that it is there. I have been surprised at the
vagueness with which such subjects will often trace upon blank paper the
outlines of the pictures which they say they ' see ' thereupon. On the othei
THE PERCEPTION OF THINGS. V2&
ral poiint de repere is used in an enormous number, not only
of hypnotic hallucinations, but of hallucinations of the
insane. These latter are often unilateral ; that is, the patient
hears the voices always on one side of him, or sees the
figure only when a certain one of his eyes is open. In
many of these cases it has been distinctly proved that a
morbid irritation in the internal ear, or an opacity in the
humors of the eye, was the starting point of the current
which the patient's diseased acoustic or optical centres
clothed with their peculiar products in the way of ideas.
Hallucinations produced in this way are 'illusions '; and M,
Binefs theory, that all hallucinations must start in the periphery ,
may be called an attempt to reduce hallucination and illusion to
one physiological type, the type, namely, to which normal per-
ception belongs. In every case, according to M. Binet,
whether of perception, of hallucination, or of illusion, we
get the sensational vividness by means of a current from
the peripheral nerves. It may be a mere trace of a cur-
rent. But that trace is enough to kindle the maximal or
supra-ideational process so that the object perceived will
have the character of externality. What the nature of the
object shall be will depend wholly on the particular sys-
tem of paths in which the process is kindled. Part of the
thing in all cases comes from the sense-organ, the rest is
furnished by the mind. But we cannot by introspection
distinguish between these parts ; and our only formula for
the result is that the brain has reacted on the impression in
the normal way. Just so in the dreams which we have
considered, and in the hallucinations of which M. Binet
tells, we can only say that the brain has reacted in an abnor-
mal way.
M. Bincfs theory accounts indeed for a multitude of cases^
but certainly not for all. The prism does not always double
liand, you will hear them say that they find no difference between a real
flower which you show them and an imaginary flower which you tell
them is beside it. When told that one is imaginary and that they must
pick out the real one, they sometimes say the choice is impossible, and
•ometimes they point to the imaginary flower.
I
130 PSYCHOLOGY.
the false appearance,*" nor does the latter always disappeai
when the eyes are closed. Dr. Hack Tuke f gives several
examples in sane people of well-exteriorized hallucinations
which did not respond to Binet's tests ; and Mr. Edmund
Gurney X gives a number of reasons why intensity in a cor-
tical process may be expected to result from local patho-
logical activity just as much as its peculiar nature does.
For Binet, an abnormally or exclusively active part of the
cortex gives the nature of what shall appear, whilst a pe-
ripheral sense-organ alone can give the intensity sufficient to
make it appear projected into real space. But since this
intensity is after all but a matter of degree, one does not see
why, under rare conditions, the degree in question might
not be attained by inner causes exclusively. In that case
we should have certain hallucinations centrally initiated
alongside of the peripherally initiated hallucinations, which
are the only sort that M. Binet's theory allows. It seems
probable on the whole, therefore, that centrally initiated hallu-
cinations can exist. How often they do exist is another ques-
tion. The existence of hallucinations which affect more
than one sense is an argument for central initiation. For
grant that the thing seen ma-y have its starting point in the
outer world, the voice which it is heard to utter must be
due to an influence from the visual region, i.e. must be of
central origin.
Sporadic cases of hallucination, visiting people only
once in a lifetime (which seem to be by far the most fre-
quent- type), are on any theory hard to understand in detail
They are often extraordinarily complete ; and the fact that
many of them are reported as veridical, that is, as coincid-
ing with real events, such as accidents, deaths, etc. , of the
persons seen, is an additional complication of the phe-
nomenon. The first really scientific study of hallucinatioD
* Only the other day, in three hypnotized girls, I failed to double as
hallucination with a prism. Of course it may not have been a fully-
developed hallucination.
t Brain, xi. 441 .
XMind, X. 161, 816 ; and Phantasms of "*»« Living (1886), i. 470-488.
THE PERCEPTION OF TEINQ8. 181
iu all its possible bearings, on the basis of a large mass of
empirical material, was begun by Mr. Edmund Gurney and
is continued by other members of the Society for Psy-
chical Research ; and the * Census ' is now being applied
to several countries under the auspices of the International
Congress of Experimental Psychology. It is to be hoped
that out of these combined labors something solid will
eventually grow. The facts shade off into the phenomena
of motor automatism, trance, etc.; and nothing but a wide
comparative study can give really instructive results.^
The part played by the peripheral sense-organ in hallucina-
tion is just as obscure as we found it in the case of imagina-
tion. The things seen often seem opaque and hide the
background upon which they are projected. It does not
follow from this, however, that the retina is actually in-
volved in the vision. A contrary process going on in the
visual centres would prevent the retinal impression made
by the outer realities from being felt, and this would in
mental terms be equivalent to the hiding of them by the
imaginary figure. The negative after-images of mental
pictures reported by Meyer and Fere, and the negative after-
images of hypnotic hallucinations reported by Binet and
others so far constitute the only evidence there is for the
retina being involved. But until these after-images are
explained in some other way we must admit the possibility
of a centrifugal current from the optical centres downwards
into the peripheral organ of sight, paradoxical as the course
of such a current may appear.
* PERCEPTION-TIME.*
The time which the perceptive process occupies has been
inquired into by various experimenters. Some call it per-
ception-time, some choice-time, some di^scrimination-tima
The results have been already given in Chapter XIII (vol
I, p. 623 ff.), to which the reader is consequently inferred.
* In Mr. Curacy's work, just cited, a very large Qumber ot veridic&i
caaes are critically discussed.
132 P8Y0H0L00T.
Dr. Komanes gives an interesting variation of these
tirae-ineasiirements. He found *
" an astonishing difference between different individuals with respect
to the rate at which they are able to read. Of course reading implies
enormously intricate processes of perception both of the sensuous and
of the intellectual order ; but if we choose for these observations per-
sons who have been accustomed to read much, we may consider that
they are all very much on a par with respect to the amount of practice
which they have had, so that the differences in their rates of reading
may fairly be attributed to real differences in their rates of forming
complex perceptions in rapid succession, and not to any merely acci-
dental differences arising from greater or less facility acquired by
«pecial practice.
*' My experiments consisted in marking a brief printed paragraphia
a book which had never been read by any of the persons to whom it
was to be presented. The paragraph, which contained simple state-
ments of simple facts, was marked on the margin with pencil. The
book was then placed before the reader open, the page, however, being
covered with a sheet of paper. Having pointed out to the reader upon
this sheet of paper what part of the underlying page the marked para-
graph occupied, I suddenly removed the sheet of paper with one hand,
while I started a chronograph with the other. Twenty seconds being
allowed for reading the paragraph (ten lines octavo), as soon as the
time was up I again suddenly placed the sheet of paper over the printed
page, passed the book on to the next reader, and repeated the experi-
ment as before. Meanwhile, the first reader, the moment after the
book had been removed, wrote down all that he or she could remember
having read. And so on with all the other readers.
"Now the results of a number of experiments conducted on this
method were to show, as I have said, astonishing differences in the
maximum rate of reading which is possible to different individuals, all
of whom have been accustomed to extensive reading. That is to say,
the difference may amount to 4 to 1 ; or, otherwise stated, in a given
time one individual may be able to read four times as much as another.
Moreover, it appeared that there was no relationship between slowness
of reading and power of assimilation ; on the contrary, when all the
efforts are directed to assimilating as much as possible in a given time,
the rapid readers (as shown by their written notes) usually give a bet-
ter account of the portions of the paragraph which have been com-
passed by the slow readers than the latter are able to give ; and the
ntost rapid reader I have found is also the best at assimilating. I
should further say that there is no relationship between rapidity of
perception as thus tested and intellectual activity as tested by the gen-
eral results of intellectual work ; for I have tried the experiment with
* Mental Evolution in Animals, d- l^&
THE PBBOEPTION OF THINGS.
133
several highly distinguished men in science and literature, most of
whom I found to be slow readers."*
* Literature. The best treatment of perception with which I am ac-
quainted is that in Mr. James Sully's book on ' Illusions ' in the Interna-
tional Scientific Series. On hallucinations the literature is large. Gurney,
Kandinsky (as already cited), and some articles by Kraepelin in the
Vierteljahrschrift ftir Wissenschaftliche Philosophic, vol. v (1881), are
the most systematic studies recently made. All works on Insanity treat
of them. Dr. W. W. Ireland's works, ' The Blot upon the Brain ' (1886) and
* Through the Ivory Gate ' (1890) have much information on the subject.
Gurney gives pretty complete references to older literature. The most
important thing on the subject from the point of view of theory is the
article by Mr. Myers on the Demon of Socrates in the Proceedings of the
Society for Psychical Research for 1889, p. 522.
CHAPTEK XX.
THE PERCEPTION OF SPACE.*
THE FEELING OF CBUDE EXTENSITT.
In the sensations of hearing, tofich, sight, and pain we are
accustomed to distinguish from among the other elements the
element of voluminousness. We call the reverberations of a
thunderstorm more voluminous than the squeaking of a
slate-pencil ; the entrance into a warm bath gives our skin
a more massive feeling than the prick of a pin ; a little
neuralgic pain, fine as a cobweb, in the face, seems less ex-
tensive than the heavy soreness of a boil or the vast discom-
fort of a colic or a lumbago ; and a solitary star looks smaller
than the noonday sky. In the sensation of dizziness or
subjective motion, which recent investigation has proved
to be connected with stimulation of the semi-circular canals
of the ear, the spatial character is very prominent. Whether
the * muscular sense ' directly yields us knowledge of space
is still a matter of litigation among psychologists. Whilst
some go so far as to ascribe our entire cognition of exten-
sion to its exclusive aid, others deny to it all extensive
quality whatever. Under these circumstances we shall do
better to adjourn its consideration ; admitting, however, that
it seems at first sight as if we felt something decidedly
more voluminous when we contract our thigh-muscles than
when we twitch an eyelid or some small muscle in the face.
It seems, moreover, as if this difference lay in the feeling
of the thigh-muscles themselves.
In the sensations of smell and taste this element of
varying vastness seems less prominent but not altogether
absent. Some tastes and smells appear less extensive than
complex flavors, like that of roast meat or plum pudding,
on the one hand, or heavy odors like musk or tuberose, on
* Reprinted, with considerable revision, from ' Mind ' for 1887.
184
THE FEUCEPTION of aPAOE. 136
the other. The epithet sharp given to the acid class would
seem to show that to the popular iniud there is something
narrow and, as it were, streaky, in the impression they
make, other flavors and odors being bigger and rounder.
The sensations derived from the inward organs are also
distinctly more or less voluminous. Bepletion and empti-
ness, suffocation, palpitation, headache, are examples of
this, and certainly not less spatial is the consciousness we
have of our general bodily condition in nausea, fever, heavy-
drowsiness, and fatigue. Our entire cubic content seems
then sensibly manifest to us as such, and feels much larger
than any local pulsation, pressure, or discomfort. Skin
and retina are, however, the organs in which the space-
element plays the most active part. Not only does the
maximal vastness yielded by the retina surpass that yielded
by any other organ, but the intricacy with which our atten-
tion can subdivide this vastness and perceive it to be com-
posed of lesser portions simultaneously coexisting along-
side of each other is without a parallel elsewhere.* The
ear gives a greater vastness than the skin, but is consider-
ably less able to subdivide it.t
Now my first thesis is that this element, discernible in each
and every sensation, though more developed in some than in
others, is the original sensation of space, out of which all the
exact knowledge about space that we afterwards come to
have is woven by processes of discrimination, association,
and selection. * Extensity,' as Mr. James "Ward calls it,:|:
* Prof. Jastrow has found that invariably we tend to underestimate the
amount of our skin which may be stimulated by contact with an object
when we express it in terms of visual space; that is, when asked to mark
on paper the extent of skin affected, we always draw it much too small.
This shows that the eye gets as much space-feeling from the smaller line as
the skin gets from the larger one. Cf. Jastrow : Mind, xi. 546-7; Ameri-
can Journal of Psychology, iii. 53.
f Amongst sounds the graver ones seem the most extensive. Stumpf
gives three reasons for this: 1) association with bigger causes; 3) wider
reverberation of the hand and body when grave notes are sung; 3) audi-
bility at a greater distance. He thinks that these three reasons dispense us
from supposing an immanent extensity in the sensation of sound as such.
See his remarks in the Tonpsychologie, i. 207-211.
% Encyclopaedia Britannica, 9th Edition, article Psychology, pp. 46, 58.
136 P8TGE0L007.
on this view, becomes an element in each sensation just as
intensity is. The latter every one will admit to be a dis-
tinguishable though not separable ingredient of the sensible
quality. In like manner extensity, being an entirely pecul-
iar kind of feeling indescribable except in terms of itself,
and inseparable in actual experience from some sensational
quality which it must accompany, can itself receive no
other name than that of sensational dement.
It must now be noted that the vastness hitherto spoken of
is as great in one direction as in another. Its dimensions are
so vague that in it there is no question as yet of surface
as opposed to depth ; ' volume ' being the best short name
for the sensation in question. Sensations of different orders
are roughly comparable, inter se, with respect to their volumes.
This shows that the spatial quality in each is identical
wherever found, for different qualitative elements, e.g.
warmth and odor, are incommensurate. Persons born
blind are reported surprised at the largeness with which
objects appear to them when their sight is restored. Franz
says of his patient cured of cataract : " He saw everything
much larger than he had supposed from the idea obtained
by his sense of touch. Moving, and especially living,
objects appeared very large." * Loud sounds have a cer-
tain enormousness of feeling. It is impossible to conceive
of the explosion of a cannon as filling a small space. In
general, sounds seem to occupy all the room between us
and their source ; and in the case of certain ones, the
cricket's song, the whistling of the wind, the roaring of the
surf, or a distant railway train, to have no definite start-
ing point.
In the sphere of vision we have facts of the same order.
'Glowing' bodies, as Hering says, give us a perception
"which seems roomy (raumhaft) in comparison with that
of strictly surface color. A glowing iron looks luminous
through and through, and so does a flame." t A luminous
fog, a band of sunshine, affect us in the same way. As
Hering urges :
* Philosophical Transactions (1841).
i Hermann's Handb. d. Physiol., Bd. in. 1, S. 576.
THE PERCEPTION OF 8PA0E. 137
" We must distinguish roomy from superficial, as well as distinctly
from indistinctly bounded, sensations. The dark which with closed eyes
one sees before one is, for example, a roomy sensation. We do not see
a black surface like a wall in front of us, but a space filled with dark-
ness, and even when we succeed in seeing this darkness as terminated
by a black wall there still remains in front of this wall the dark space.
The same thing happens when we find ourselves with open eyes in an
absolutely dark room. This sensation of darkness is also vaguely
bounded. An example of a distinctly bounded roomy sensation is that
of a clear and colored fluid seen in a glass ; the yellow of the wine is
seen not only on the bounding surface of the glass ; the yellow sensa-
tion fills the whole interior of the glass. By day the so-called empty
space between us and objects seen appears very different from what it
is by night. The increasing darkness settles not only upon the things
but also between us and the things, so as at last to cover them com-
pletely and fill the space alone. If I look into a dark box I find it filled
with darkness, and this is seen not merely as the dark-colored sides or
walls of the box. A shady corner in an otherwise well-lighted room is
full of a darkness which is not only on the walls and floor but between
them in the space they include. Every sensation is there where I ex-
perience it, and if I have it at once at every point of a certain roomy
space, it is then a voluminous sensation. A cube of transparent green
glass gives us a spatial sensation ; an opaque cube painted green, on
the contrary, only sensations of surface. " *
There are certain quasi-motor sensations in the head when
we change the direction of the attention, which equally seem
to involve three dimensions. If with closed eyes we think
of the top of the house and then of the cellar, of the distance
in front of us and then of that behind us, of space far to the
right and then far to the left, we have something far stronger
than an idea, — an actual feeling, namely, as if something in
the head moved into another direction. Fechner was, I
believe, the first to publish any remarks on these feelings.
He writes as follows :
" When we transfer the attention from objects of one sense to those
of another we have an indescribable feeling (though at the same time
one perfectly determinate and reproducible at pleasure) of altered direc-
tion, or differently localized tension {Spannung). We feel a strain for-
ward in the eyes, one directed sideways in the ears, increasing with
the degree of our attention, and changing according as we look at an
object carefully, or listen to something attentively ; wherefore we speak
of straining the attention. The difference is most plainly felt when
* Loc. dt. S. 672.
168 PSYCHOLOGY.
the attention vibrates rapidly between eye and ear. This feeling local-
izes itself with most decided difference in regard to the various sense-
organs according as we wish to discriminate a thing delicately by touch,
taste, or smell.
' ' But now I have, when I try to vividly recall a picture of memory
or fancy, a feeling perfectly analogous to that which I experience when
I seek to grasp a thing keenly by eye or ear ; and this analogous feeling
is very differently localized. While in sharpest possible attention to
real objects (as well as to after-images) the strain is plainly forwards,
and, when the attention changes from one sense to another, only alters
its direction between the sense-organs, leaving the rest of the head free
from strain, the case is different in memory or fancy ; for here the feel-
ing withdraws entirely from the external sense-organs, and seems rather
to take refuge in that part of the head which the brain fills. If I wish,
for example, to recall a place or person, it will arise before me with
vividness, not according as I strain my attention forwards, but rather
in proportion as I, so to speak, retract it backwards."*
It appears probable that the feelings which Fechner de-
scribes are in part constituted by imaginary semi-circular
canal sensations. f These undoubtedly convey the most
delicate perception of change in direction ; and when, as
here, the changes are not perceived as taking place in the
external world, they occupy a vague internal space located
within the head.:]:
* Elemente der Psychophysik, ii. 475-6.
f See Foster's Text-book of Physiology, bk. iii. c. vi. § 2.
X Fechner, who was ignorant of the but lately discovered function of
the semi-circular canals, gives a different explanation of the organic seat of
these feelings. They are probablj'^ highly composite. With me, actual move-
ments in the eyes play a considerable part in them, though I am hardly con-
scious of the peculiar feelings in the scalp which Fechner goes on to de-
scribe thus : "The feeling of strained attention in the different sense-organs
seems to be only a muscular one produced in using these various organs
by setting in motion, by a sort of reflex action, the set of muscles which
belong to them. One can ask, then, with what particular muscular con-
traction the sense of strained attention in the effort to recall something is
associated ? On this question my own feeling gives me a decided answer ;
it comes to me distinctly not as a sensation of tension in the inside of the
head, but as a feeling of strain and contraction in the scalp, with a pressure
from outwards in over the whole cranium, undoubtedly caused by a con-
traction of the muscles of the scalp. This harmonizes very well with the
expressions, sich den Kopf zerhrecTien, den Kopf zusammennehmen. In a
former illness, when I could not endure the slightest effort after continuous
thought, and had no theoretical bias on this question, the muscles of the
scalp, especially those of the back-head, assumed a fairly morbid degree of
sensibility whenever I tried to think." (Elem. der Psychophysik, ii
490-91.)
»
THE PERCEPTION OF SPACE. 139
In the skin itself there is a vague form of projection
into the third dimension to which Hering has called atten-
tion.
"Heat is not felt only against the cutaneous surface, but when com-
municated through the air may appear extending more or less out from
the surface into the third dimension of surrounding space. . . . We
can determine in the dark the place of a radiant body by moving the
hand to and fro, and attending to the fluctuation of our feeling of
warmth. The feeling itself, however, is not projected fully into the
spot at which we localize the hot body, but always remains in the
neighborhood of the hand."
The interior of one's mouth-cavity feels larger when ex-
plored by the tongue than when looked at. The crater of a
newly-extracted tooth, and the movements of a loose tooth
in its socket, feel quite monstrous. A midge buzzing
against the drum of the ear will often seem as big as a but-
terfly. The spatial sensibility of the tympanic membrane
has hitherto been very little studied, though the subject
will well repay much trouble. If we approach it by intro-
ducing into the outer ear some small object like the tip of
a rolled-up tissue-paper lamplighter, we are surprised at
the large radiating sensation which its presence gives us,
and at the sense of clearness and openness which comes
when it is removed. It is immaterial to inquire whether
the far-reaching sensation here be due to actual irradiation
upon distant nerves or not. "We are considering now, not
the objective causes of the spatial feeling, but its subjective
varieties, and the experiment shows that the same object
gives more of it to the inner than to the outer cuticle of
the ear. The pressure of the air in the tympanic cavity
upon the membrane gives an astonishingly large sensation.
We can increase the pressure by holding our nostrils and
closing our mouth and forcing air through our Eustachian
tubes by an expiratory effort ; and we can diminish it by
either inspiring or swallowing under the same conditions of
closed mouth and nose. In either case wc get a large round
tridimensional sensation inside of the head, which seems
as if it must come from the affection of an organ much
larger than the tympanic membrane, whose surface hardly
exceeds that of one's little-finger-nail.
140 P870nOL007,
The tympanic membrane is furthermore able to render
sensible differences in the pressure of the external atmos-
phere, too slight to be felt either as noise or in this more
violent way. If the reader will sit with closed eyes and let
a friend approximate some solid object, like a large book,
noiselessly to his face, he will immediately become aware
of the object's presence and position — likewise of its de-
parture. A friend of the writer, making the experiment
for the first time, discriminated unhesitatingly between the
three degrees of solidity of a board, a lattice-frame, and a
sieve, held close to his ear. Now as this sensation is never
used by ordinary persons as a means of perception, we may
fairly assume that its felt quality, in those whose attention
is called to it for the first time, belongs to it qua sensation,
and owes nothing to educational suggestions. But this felt
quality is most distinctly and unmistakably one of vague
spatial vastness in three dimensions — quite as much so as
is the felt quality of the retinal sensation when we lie on
our back and fill the entire field of vision with the empty
blue sky. When an object is brought near the ear we im-
mediately feel shut in, contracted ; when the object is
removed, we suddenly feel as if a transparency, clearness,
openness, had been made outside of us. And the feeling
will, by any one who will take the pains to observe it, be
acknowledged to involve the third dimension in a vague,
unmeasured state.*
The reader will have noticed, in this enumeration of
facts, that voluminousness of the feeling Seems to bear very little
relation to the size of the organ that yields it. The ear and
eye are comparatively minute organs, yet they give us feel-
ings of great volume. The same lack of exact proportion
between size of feeling and size of organ affected obtains
within the limits of particular sensory organs. An object
appears smaller on the lateral portions of the retina than it
does on the fovea, as may be easily verified by holding the
* That the sensation in question is one of tactile rather than of acoustic
sensibility would seem proved by the fact that a medical friend of the
writer, both of whose membrarm tympani are quite normal, but one of
whose ears is almost totally deaf, feels the presence and withdrawal of ob-
JecU M well at one ear as at the other.
THE PERCEPTION OP SPACE. 141
two forefingers parallel and a couple of inches apart, and
transferring the gaze of one eye from one to the other.
Then the finger not directly looked at will appear to shrink,
and this whatever be the direction of the fingers. On the
tongue a crumb, or the calibre of a small tube, appears
larger than between the fingers. If two points kept equi-
distant (blunted compass- or scissors-points, for example)
be drawn across the skin so as really to describe a pair of
parallel lines, the lines will appear farther apart in some
spots than in others. If, for example, we draw them hori-
zontally across the face, so that the mouth falls between
them, the person experimented upon will feel as if they
began to diverge near the mouth and to include it in a well-
marked ellipse. In like manner, if we keep the compass-
Fio. 61 (after Weber).
points one or two centimetres apart, and draw them down
the forearm over the wrist and palm, finally drawing one
along one finger, the other along its neighbor, the appear-
ance will be that of a single line, soon breaking into two,
which become more widely separated below the wrist, to
contract again in the palm, and finally diverge rapidly
again towards the finger-tips. The dotted lines in Figs.
51 and 52 represent the true path of the compass-points ;
the full lines their apparent path.
The same length of skin, moreover, will convey a more
extensive sensation according to the manner of stimulation.
If the edge of a card be pressed against the skin, the dis-
tance between its extremities will seem shorter than that be-
tween two compass-tips touching the same terminal points.*
* The skin seems to obey a different law from the eye here. If a given
retinal tract be excited, first by a series of points, and next by the two
142
PSYCHOLOGY,
In the eye, intensity of nerve-stimulation seems to in-
crease the volume of the feeling as well
as its brilliancy. If we raise and lower
the gas alternately, the whole room and
all the objects in it seem alternately to
enlarge and contract. If we cover half
a page of small print with a gray glass, the
print seen through the glass appears
decidedly smaller than that seen outside
of it, and the darker the glass the greater
the difference. When a circumscribed
opacity in front of the retina keeps off
part of the light from the portion which
it covers, objects projected on that
portion may seem but half as large as
when their image falls outside of it.*
The inverse effect seems produced by
certain drugs and anaesthetics. Mor-
phine, atropine, daturine, and cold blunt
the sensibility of the skin, so that dis-
tances upon it seem less. Haschish pro-
duces strange perversions of the general
sensibility. Under its influence one's
body may seem either enormously en-
larged or strangely contracted. Some-
times a single member will alter its
proportion to the rest ; or one's back,
for instance, will appear entirely absent,
as if one were hollow behind. Objects
comparatively near will recede to a vast
distance, a short street assume to the
eye an immeasurable perspective. Ether and chloroform
i> c a
Pio. 62 (after Weber)
extreme points, with the interval between them unexcited, this interval will
seem considerably less in the second case than it seemed in the first. In
the skin the unexcited interval feels the larger. The reader may easily
verify the facts in this case by taking a visiting-card, cutting one edge of
it into a saw-tooth pattern, and from the opposite edge cutting out all but
the two corners, and then comparing the feelings aroused by the two edges
when held against the skin.
* Classen, Physiologic des Gesichtssinnes, p. 114 ; see also A. Riehl, Der
Philosophische Kriticismus, ii. p. 149.
THE PERCEPTION OF SPACE. 143
occasionally produce not wholly dissimilar results. Panum,
the German physiologist, relates that when, as a boy, he
was etherized for neuralgia, the objects in the room grew
extremely small and distant, before his field of vision dark-
ened over and the roaring in his ears began. He also men-
tions that a friend of his in church, struggling in vain to
keep awake, saw the preacher grow smaller and smaller
and more and more distant. I myself on one occasion
observed the same recession of objects during the begin-
ning of chloroformization. In various cerebral diseases
we find analogous disturbances.
Can we assign the physiological conditions which make the
elementary sensible largeness of one sensation vary so miich/rom
that of another ? Only imperfectly. One factor in the re-
sult undoubtedly is the number of nerve-terminations
simultaneously excited by the outward agent that awakens
the sensation. When many skin-nerves are warmed, or
much retinal surface illuminated, our feeling is larger than
when a lesser nervous surface is excited. The single sen-
sation yielded by two compass-points, although it seems
simple, is yet felt to be much bigger and blunter than that
yielded by one. The touch of a single point may always
be recognized by its quality of sharpness. This page looks
much smaller to the reader if he closes one eye than if both
eyes are open. So does the moon, which latter fact shows
that the phenomenon has nothing to do with parallax.
The celebrated boy couched for the cataract by Cheselden
thought, after his first eye was operated, " all things he saw
extremely large," but being couched of his second eye,
said " that objects at first appeared large to this eye, but
not so large as they did at first to the other ; and looking
upon the same object with both eyes, he thought it looked
about twice as large as with the first couched eye only, but
not double, that we can anyways discover."
The greater extensiveness that the feeling of certain
parts of the same surface has over other parts, and that
one order of surface has over another (retina over skin, for
example), may also to a certain extent be explained by the
operation of the same factor. It is an anatomical fact that
the most spatially sensitive surfaces (retina, tongue, finger-
144 PSYGHOLOQT.
tips, etc.) are supplied by nerve-trunks of unusual thick-
ness, which must supply to every unit of surface-area an
unusually large number of terminal fibres. But the varia-
tions of felt extension obey probably only a very rough law
of numerical proportion to the number of fibres. A sound
is not twice as voluminous to two ears as to one ; and the
above-cited variations of feeling, when the same surface is
excited under different conditions, show that the feeling is
a resultant of several factors of which the anatomical one
is only the principal. Many ingenious hypotheses have
been brought forward to assign the co-operating factors
where different conditions give conflicting amounts of felt
space. Later we shall analyze some of these cases in de-
tail, but it must be confessed here in advance that many of
them resist analysis altogether. *
* It is worth while at this point to call attention with some emphasis to
the fact that, though the anatomical condition of the feeling resembles the
feeling itself, such resemblance cannot be taken by our understanding to
explain why the feeling should be just what it is. We hear it untiringly
reiterated by materialists and spiritualists alike that we can see no possible
inward reason why a certain brain-process should produce the feeling of
redness and another of anger : the one process is no more red than the
other is angry, and the coupling of process and feeling is, as far as our
understanding goes, a juxtaposition pure and simple. But in the matter of
spatial feeling, where the retinal patch that produces a triangle in the mind
is itself a triangle, etc. , it looks at first sight as if the sensation might be a
direct cognition of its own neural condition. Were this true, however, our
sensation should be one of multitude rather than of continuous extent ; for
the condition is nw7w&<?r of optical nerve-termini, and even this is only a
remote condition and not an immediate condition. The immediate condi-
tion of the feeling is not the process in the retina, but the process in the
brain ; and the process in the brain may, for aught we know, be as unlike
a triangle, — nay, it probably is so, — as it is unlike redness or rage. It is
simply a coincidence that in the case of space one of the organic conditions,
viz., the triangle impressed on the skin or the retina, should lead to a rep-
resentation in the mind of the subject observed similar to that which it
produces in the psychological observer. In no other kind of case is the
coincidence found. Even should we admit that we cognize triangles in
space because of our immediate cognition of the triangular shape of our
excited group of nerve-tips, the matter would hardly be more transparent,
for the mystery would still remain, why are we so much better cognizant
of triangles on our finger-tips than on the nerve-tips of our back, on our
eye than on our ear, and on any of these parts than in our brain ? Thos.
Brown very rightly rejects the notion of explaining the shape of the space
perceiyed by the shape of the 'nervous expansion affected.' "If this
THE PERCEPTION OF SPACE. 146
THE PEKCEPTION OF SPATIAL OBDEB.
So far, all we have established or sought to establish is
the existence of the vague form or qicale of spatiality as an
inseparable element bound up with the other peculiarities
of each and every one of our sensations. The numerous
examples we have adduced of the variations of this extensive
element have only been meant to make clear its strictly
sensational character. In very few of them will the reader
have been able to explain the variation by an added intel-
lectual element, such as the suggestion of a recollected ex-
perience. In almost all it has seemed to be the immediate
psychic effect of a peculiar sort of nerve-process excited ;
and all the nerve-processes in question agree in yielding
what space they do yield, to the mind, in the shape of a
simple total vastness, in which, primitively at least, no order
of parts or of subdivisions reigns.
Let no one be surprised at this notion of a space without
order. There may be a space without order just as there
may be an order without space.^ And the primitive percep-
tions of space are certainly of an unordered kind. The
order which the spaces first perceived potentially include
must, before being distinctly apprehended by the mind, be
woven into those spaces by a rather complicated set of in-
tellectual acts. The primordial largenesses which the sen-
sations yield must be measured and subdivided by conscious-
ness, and added together, before they can form by their
synthesis what we know as the real Space of the objective
world. In these operations, imagination, association, at-
tention, and selection play a decisive part ; and although
they nowhere add any new material to the space-data of
sense, they so shuffle and manipulate these data and hide
alone were necessary, we should have square Inches and half inches, and
various other forms, rectilinear and curvilinear, of fragance and sound."
(Lectures, xxii.)
* Musical tones, e.g., have an order of quality independent either of
their space- or time-order. Music comes from the time-order of the notes
upsetting their quality- order. In general, \i ab c d efg h ij k, etc., stand
for an arrangement of feelings in the order of their quality, they may as-
sume anp space-order or time-order, SiS d ef a h g, etc., and still the order
of quality will remain fixed and unchanged.
146 PSYCHOLOGY,
present ones behind imagined ones that it is no wonder if
some authors have gone so far as to think that the sense-
data have no spatial worth at all, and that the intellect,
since it makes the subdivisions, also gives the spatial
quality to them out of resources of its own.
As for ourselves, having found that all our sensations
(however as yet unconnected and undiscriminated) are of
extensive objects, our next problem is : How do we arrange
these at first chaotically given spaces into the one regular and
orderly * world of spa^e ' which we now know ?
To begin with, there is no reason to suppose that the
several sense-spaces of which a sentient creature may
become conscious, each filled with its own peculiar content,
should tend, simply because they are manyj to enter into
any definite spatial intercourse with each other, or lie in
any particular order of positions. Even in ourselves we
can recognize this. Different feelings may coexist in us
without assuming any particular spatial order. The sound
of the brook near which I write, the odor of the cedars, the
comfort with which my breakfast has filled me, and my in-
terest in this paragraph, all lie distinct in my consciousness,
but in no sense outside or alongside of each other. Their
spaces are interfused and at most fill the same vaguely ob-
jective world. Even where the qualities are far less dis-
parate, we may have something similar. If we take our
subjective and corporeal sensations alone, there are moments
when, as we lie or sit motionless, we find it very difiicult to
feel distinctly the length of our back or the direction of our
feet from our shoulders. By a strong effort we can succeed
in dispersing our attention impartially over our whole per-
son, and then we feel the real shape of our body in a sort
of unitary way. But in general a few parts are strongly
emphasized to consciousness and the rest sink out of notice ;
and it is then remarkable how vague and ambiguous our
perception of their relative order of location is. Obviously,
for the orderly arrangement of a multitude of sense-spaces
in consciousness, something more than their mere separate
existence is required. What is this further condition ?
If a number of sensible extents art to be perceived alongside
THE PERCEPTION OF SPACE. 147
of each other and in definite order they must appear as parts in
a vaster sensible extent which can enter the mind simply and all
at once. I think it will be seen that the difficulty of esti-
mating correctly the form of one's body by pure feeling
arises from the fact that it is very hard to feel its totality aw
a unit at all. The trouble is similar to that of thinking for-
wards and backwards simultaneously. When conscious of
our head we tend to grow unconscious of our feet, and there
enters thus an element of time-succession into our percep-
tion of ourselves which transforms the latter from an act of
intuition to one of construction. This element of con-
structiveness is present in a still higher degree, and carries
with it the same consequences, when we deal with objective
spaces too great to be grasped by a single look. The rela-
tive positions of the shops in a town, separated by many
tortuous streets, have to be thus constructed from data ap-
prehended in succession, and the result is a greater or less
degree of vagueness.
That a sensation he discriminated as a part from out of a
larger enveloping space is then the conditio sine qua non of its
being apprehended in a definite spatial order. The problem
of ordering our feelings in space is then, in the first instance,
a problem of discrimination, but not of discrimination pure
and simple ; for then not only coexistent sights but coex^
istent sounds would necessarily assume such order, which
they notoriously do not. Whatever is discriminated will
appear as a small space within a larger space, it is true, but
this is but the very rudiment of order. For the location of
it within that space to become precise, other conditions still
must supervene ; and the best way to study what they are
will be to pause for a little and amdyze what the expression
'spatial order ^ nfieans.
Spatial order is an abstract term. The concrete percep*
tions which it covers are figures, directions, positions, mag-
nitudes, and distances. To single out any one of these
things from a total vastness is partially to introduce order
into the vastness. To subdivide the vastness into a multi-
tude of these things is to apprehend it in a completely
orderly way. Now what are these things severally ? To
148 PSYCHOLOGY.
begin with, no one can for an instant hesitate to say thai
some of them are qualities of sensation, just as the total
vastness is in which they lie. Take figure : a square, a
circle, and a triangle appear in the first instance to the eye
simply as three different kinds of impressions, each so pecul-
iar that we should recognize it if it were to return. When
Nunnely's patient had his cataracts removed, and a cube and
a sphere were presented to his notice, he could at once
perceive a difference in their shapes ; and though he could
not say which was the cube and which the sphere, he saw
they were not of the same figure. So of lines : if we can
notice lines at all in our field of vision, it is inconceivable
that a vertical one should not affect us differently from an
horizontal one, and should not be recognized as affecting us
similarly when presented again, although we might not yet
know the name * vertical,' or any of its connotations, beyond
this peculiar affection of our sensibility. So of angles : an
obtuse one affects our feeling immediately in a different way
from an acute one. Distance-apart, too, is a simple sensa-
tion — the sensation of a line joining the two distant points :
lengthen the line, you alter the feeling and with it the
distance felt.
B'pcme-rdations.
But with distance and direction we pass to the category
of space-reZafiow5, and are immediately confronted by an
opinion which makes of all relations something toto codo
different from all facts of feeling or imagination whatsoever.
A relation, for the Platonizing school in psychology, is an
energy of pure thought, and, as such, is quite incommen-
surable with the data of sensibility between which it may
be perceived to obtain.
We may consequently imagine a disciple of this school
to say to us at this point : " Suppose you have made a sep-
arate specific sensation of each line and each angle, what
boots it? You have still the order of directions and of
distances to account for ; you have still the relative magni-
tudes ol all these felt figures to state ; you have their re-
spective positions to define before you can be said to have
brought order into your space. And not one of these de-
i
THE PERCEPTION OF 8PA0B. 149
terminations can be effected except through an act of re-
lating thought, so that your attempt to give an account of
space in terms of pure sensibility breaks down almost at
the very outset. Position, for example, can never be a sen-
sation, for it has nothing intrinsic about it ; it can only
obtain between a spot, line, or other figure and extraneous
co-ordinates, and can never be an element of the sensible
datum, the line or the spot, in itself. Let us then confess
that Thought alone can unlock the riddle of space, and
that Thought is an adorable but unfathomable mystery."
Such a method of dealing with the problem has the
merit of shortness. Let us, however, be in no such hurry,
but see whether we cannot get a little deeper by patiently
considering what these space-relations are.
*Kelation' is a very slippery word. It has so many
different concrete meanings that the use of it as an abstract
universal may easily introduce bewilderment into our
thought. We must therefore be careful to avoid ambiguity
by making sure, wherever we have to employ it, what its
precise meaning is in that particular sphere of application.
At present we have to do with space-relations, and no others.
Most * relations ' are feelings of an entirely different order
from the terms they relate. The relation of similarity, e.g.,
may equally obtain between jasmine and tuberose, or be-
tween Mr. Browning*s verses and Mr. Story's ; it is itself
neither odorous nor poetical, and those may well be pardoned
who have denied to it all sensational content whatever.
But just as, in the field of quantity, the relation between
two numbers is another number, so in the field of space the
relations are facts of the same order with the facts they relate.
If these latter be patches in the circle of vision, the former
are certain other patches between them. When we speak of
the relation of direction of two points toward each other,
we mean simply the sensation of the line that joins the two
points together. The line is the relation; feel it and you
feel the relation, see it and you see the relation ; nor can
you in any conceivable way think the latter except by im-
agining the former (however vaguely), or describe or indi-
cate the one except by pointing to the other. And the
moment you have imagined the line, the relation stands
150 P8YCH0L00T.
befora you in all its completeness, with nothing further to
be done. Just so the relation of direction between two lines
is identical with the peculiar sensation of shape of the
space enclosed between them. This is commonly called
an angular relation.
If these relations are sensations, no less so are the rela-
tions of position. The relation of position between the top and
bottom points of a vertical line is that line^ and nothing else.
The relations of position between a point and a horizontal
line below it are potentially numerous. There is one more
important than the rest, called its distance. This is the
sensation, ideal or actual, of a perpendicular drawn from the
point to the line.* Two lines, one from each extremity of
the horizontal to the point, give us a peculiar sensation of
triangularity. This feeling may be said to constitute the
locus of all the relations of position of the elements in ques-
tion. Rightness and hftness, upness and downness, are again
pure sensations differing specifically from each other, and
generically from everything else. Like all sensations, they
can only be indicated, not described. If we take a cube and
label one side top, another bottom, a third front, and a fourth
back, there remains no form of words by which we can de-
scribe to another person which of the remaining sides is right
and which left. We can only point and say here is right
and there is left, just as we should say this is red and that
blue. Of two points seen beside each other at all, one is
always affected by one of these feelings, and the other by
the opposite; the same is true of the extremities of any
line.f
* The whole science of geometry may be said to owe its being to the
exorbitant interest which the human mind takes in Uius. We cut space
up in every direction in order to manufacture them.
f Kant was, 1 believe, the first to call attention to this last order of facts.
After pointing out that two opposite spherical triangles, two gloves of a
pair, two spirals wound in contrary directions, have identical inward de-
terminations, that is, have their parts defined with relation to each other by
the same law, and so must be conceived as identical, he showed that the im-
possibility of their mutual superposition obliges us to assign to each figure
of a symmetrical pair a peculiar difference of its own which can only con-
sist in an outward determination or relation of its parts, no longer to each
other, but to the whole of an objectively outlying space with its points of the
compass given absolutely. This inc<??iceivable difference is perceived onli?
I
THE PERCEPTION OF 8PACE. 151
Thus it appears indubitable that all space-relations ex-
cept those of magnitude are nothing more or less than pure
sensational objects. But magnitude appears to outstep this
narrow sphere. We have relations of muchness and little-
ness between times, numbers, intensities, and qualities, as
well as spaces. It is impossible, then, that such relations
should form a particular kind of simply spatial feeling.
This we must admit : the relation of quantity is generic
and occurs in many categories of consciousness, whilst the
other relations we have considered are specific and occur
in space alone. When our attention passes from a shorter
line to a longer, from a smaller spot to a larger, from a
feebler light to a stronger, from a paler blue to a richer,
from a march tune to a galop, the transition is accompanied
in the synthetic field of consciousness by a peculiar feeling
of difference which is what we call the sensation of morey —
more length, more expanse, more light, more blue, more
motion. This transitional sensation of more must be iden-
tical with itself under all these different accompaniments,
or we should not give it the same name in every case. We
get it when we pass from a short vertical line to a long
horizontal one, from a small square to a large circle, as
well as when we pass between those figures whose shapes
are congruous. But when the shapes are congruous our
consciousness of the relation is a good deal more distinct,
and it is most distinct of all when, in the exercise of our
analytic attention, we notice, first, a part, and then the
whohf of a single line or shape. Then the more of the whole
actually sticks out, as a separate piece of space, and is so
envisaged. The same exact sensation of it is given when
we are able to superpose one line or figure on another. This
indispensable condition of exact measurement of the 7nore
has led some to think that the feeling itself arose in every
case from original experiences of superposition. This is
■'through the relation to right and left, which is a matter of immediate
intuition." In these last words {welch£s unmittelba/r auf Anschauung geht
— Prolegomena, § 12) Kant expresses all that we have meant by speaking
of up and down, right and left, as sensations. He is wrong, however, in
invoking relation to extrinsic total space as essential to the existence of
these contrasts in figures. Relation to our own body is enoxufh.
152 P8YCH0L00T.
probably not au absolutely true opinion, but for our pres-
ent purpose that is immaterial. So far as the subdivisions
of a sense -space are to be measured exactly against each
other, objective forms occupying one subdivision must
directly or indirectly be superposed upon the other, and
the mind must get the immediate feeling of an outstanding
plus. And even where we only feel one subdivision to be
vaguely larger or less, the mind must pass rapidly between
it and the other subdivision, and receive the immediate sen-
sible shock of the more.
We seem thus to have accounted for aU space-relations, and
made them clear to our understanding. They are nothing but
sensations of particular lines, particular angles, particular forms
of transition, or (in the case of a distinct more) of particular
outstanding portions of spaxie after two figures have been super-
posed. These relation-sensations may actually be produced
as such, as when a geometer draws new lines across a figure
with his pencil to demonstrate the relations of its parts,
or they may be ideal representations of lines, not really
drawn. But in either case their entrance into the mind is
equivalent to a more detailed subdivision, cognizance, and
measurement of the space considered. The bringing of sub-
divisions to consciousness constitutes, then, the entire process
by which we pass from our first vague feding of a total
vastness to a cognition of the vastness in detail. The more
numerous the subdivisions are, the more elaborate and per-
fect the cognition becomes. But inasmuch as all the sub-
divisions are themselves sensations, and even the feeling
of * more ' or * less ' is, where not itself a figure, at least a
sensation of transition between two sensations of figure,
it follows, for aught we can as yet see to the contrary,
that all spatial knowledge is sensational at bottom, and that,
as the sensations lie together in the unity of consciousness,
no new material element whatever comes to them from a
supra-sensible source.^
* In the eyes of many it will have seemed strange to call a relation a
mere line, and a line a mere sensation. We may easily learn a great deal
about any relation, say that between two points: we may divide the line
which joins these, and distinguish it, and classify it, and find out iU rela-
r
THE PERCEPTION OF SPACE. 153
Th£ bringing of svhdivisions to consciousness ! This, then,
is our next topic. They may be brought to consciousness
under three aspects in respect of their locality , in respect
of their size, in respect of their shape.
The Meaning of Localization.
Confining ourselves to the problem of locality for the pres-
ent, let us begin with the simple case of a sensitive surface,
only two points of which receive stimulation from without.
How, first, are these two points felt as alongside of each
other with an interval of space between them ? We must
be conscious of two things for this : of the duality of the ex-
cited points, and of the extensiveness of the unexcited
interval. The duality alone, although a necessary, is not a
sufficient condition of the spatial separation. We may,
for instance, discern two sounds in the same place, sweet
and sour in the same lemonade, warm and cold, round and
pointed contact in the same place on the skin, etc.''^ In all
discrimination the recognition of the duality of two feelings
by the mind is the easier the more strongly the feelings are
tions by drawing or representing new lines, and so on. But all this
further industry has naught to do with our (Acquaintance with the relation
itself, in its first intention. So cognized, the relation is the line and nothing
more. It would indeed be fair to call it something less; and in fact it is
easy to understand how most of us come to feel as if the line were a much
grosser thing than the relation. The line is broad or narrow, blue or red,
made by this object or by that alternately, in the course of our experience;
it is therefore independent of any one of these accidents; and so, from
viewing it as no one of such sensible qualities, we may end by thinking of
it as something which cannot be defined except as the negation of all sen-
sible quality whatever, and which needs to be put into the sensations by a
mysterious act of ' relating thought. '
Another reason why we get to feel as if a space-relation must be some-
thing other than the mere feeling of a line or angle is that between two
positions we can potentially make any number of lines and angles, or find,
to suit our purposes, endlessly numerous relations. The sense of this indefi-
nite potentiality cleaves to our words when we speak in a general way of
'relations of place,' and misleads us into supposing that not even any
single one of them can be exhaustively equated by a single angle or a
single line.
* This often happens when the warm and cold points, or the round and
pointed ones, are applied to the skin within the limits of a single ' Em-
pfindungskreis.'
154 PSYCHOLOGY.
contrasted in quality. If our two excited points awaken
identical qualities of sensation, they must, perforce, appear
to the mind as one ; and, not distinguished at all, they are,
a fortiori, not localized apart. Spots four centimetres dis-
tant on the back have no qualitative contrast at all, and fuse
into a single sensation. Points less than three thousandths
of a millimetre apart awaken on the retina sensations so
contrasted that we apprehend them immediately as two.
Now these unlikenesses which arise so slowly when we pass
from one point to another in the back, so much faster on
the tongue and finger-tips, but with such inconceivable
rapidity on the retina, what are they ? Can we discover
anything about their intrinsic nature ?
The most natural and immediate answer to make is that
they are unlikeness of place pure and simple. In the words
of a German physiologist,^ to whom psychophysics owes
much :
" The sensations are from the outset {von vornherein) localized. . . .
Every sensation as such is from the very beginning affected with the
spatial quality, so that this quality is nothing like an external attribute
coming to the sensation from a higher faculty, but must be regarded as
something immanently residing in the sensation itself."
And yet the moment we reflect on this answer an insu-
perable logical difficulty seems to present itself. No single
quale of sensation can, by itself, amount to a consciousness
of position. Suppose no feeling but that of a single point
ever to be awakened. Could that possibly be the feeling
of any special whereiiess or thereness ? Certainly not. Only
when a second point is fdt to arise can the first one acquire
a determination of up, down, right or left, and these determina-
tions are all relative to that second point. Each point, so far as
it is placed, is then only by virtue of what it is not, namely,
by virtue of another point. This is as much as to say that
position has nothing intrinsic about it ; and that, although a
feeling of absolute bigness may, a feeling of place cannot,
possibly form an immanent element in any single isolated sensa-
tion. The very writer we have quoted has given heed to
this objection, for he continues (p. 335) by saying that the
* Vierordt, Grundriss der Physiologie, 5te Auflage (1877), pp. 326, 48^
THE PERCEPTION OF SPACE. 155
sensations thus originally localized " are only so in them-
selves, but not in the representation of consciousness, which
is not yet present. . . . They are, in the first instance, de-
Void of all mutual relations with each other." But such a
localization of the sensation *in itself ' would seem to mean
nothing more than the susceptibility or potentiality of being
distinctly localized when the time came and other conditions
became fulfilled. Can we now discover anything about such
susceptibility in itself before it has borne its ulterior fruits
in the developed consciousness ?
^ Local Signs,*
To begin with, every sensation of the skin and every vis-
ceral sensation seems to derive from its topographic seat
a peculiar shade of feeling, which it would not have in
another place. And this feeling per se seems quite another
thing from the perception of the place. Says Wundt * :
" If with the finger we touch first the cheek and then the palm,
exerting each time precisely the same pressure, the sensation shows not-
withstanding a distinctly marked difference in the two cases. Similarly,
when Ave compare the palm with the back of the hand, the nape of the
neck with its anterior surface, the breast with the back ; in short, any
two distant parts of the skin with each other. And moreover, we easily
remark, by attentively observing, that spots even tolerably close
together differ in respect of the quality of their feeling. If we pass
from one point of our cutaneous surface to another, we find a perfectly
gradual and continuous alteration in our feeling, notwithstanding the
objective nature of the contact has remained the same. Even the sen-
sations of corresponding points on opposite sides of the body, though
similar, are not identical. If, for instance, we touch first the back of one
hand and then of the other, we remark a qualitative unlikeness of
sensation. It must not be thought that such differences are mere mat-
ters of imagination, and that we take the sensations to be different
because we represent each of them to ourselves as occupying a different
place. With sufficient sharpening of the attention, we may, confining
ourselves to the quality of the feelings alone, entirely abstract from
their locality, and yet notice the differences quite as markedly. "
*VorlesuDgen tlb. Menschen- u. Thierseele (Leipzig, 1863), i. 214. See
also Ladd's Physiological Psychology, pp. 396-8, and compare the account
by G. Stanley Hall (Mind, x. 571) of the sensations produced by moving
a blunt point lightly over the skin. Points of cutting pain, quivering,
thrilling, whirling, tickling, scratching, and acceleration, alternated with
^ach other along the surface.
166 P8T0H0L00T,
Whether these local contrasts shade into each other
with absolutely continuous gradations, we cannot say. But
we know (continues Wundt) that
"they change, when we pass from one point of the skin to its neigh-
bor, with very different degrees of rapidity. On delicately-feeling
parts, used principally for touching, such as the finger-tips, the dif-
ference of sensation between two closely approximate points is already
strongly pronounced ; whilst in parts of lesser delicacy, as the arm, the
back, the legs, the disparities of sensation are observable only between
distant spots."
The internal organs, too, have their specific qualia of sen-
sation. An inflammation of the kidney is different from
one of the liver ; pains in joints and muscular insertions
are distinguished. Pain in the dental nerves is wholly
unlike the pain of a burn. But very im.portant and curious
similarities prevail throughout these differences. Internal
pains, whose seat we cannot see, and have no means of
knowing unless the character of the pain itself reveal it,
are felt where they belong. Diseases of the stomach,
kidney, liver, rectum, prostate, ,etc., of the bones, of the
brain and its membranes, are referred to their proper posi-
tion. Nerve-pains describe the length of the nerve. Such
localizations as those of vertical, frontal, or occipital head-
ache of intracranial origin force us to conclude that parts
which are neighbors, whether inner or outer, may possess
by mere virtue of that fact a common peculiarity of feeling,
a respect in which their sensations agree, and which serves
as a token of their proximity. These local colorings are,
moreover, so strong that we cognize them as the samej
throughout all contrasts of sensible quality in the accom-
panying perception. Cold and heat are wide as the poles
asunder ; yet if both fall on the cheek, there mixes with
them something that makes them in that respect identical ;
just as, contrariwise, despite the identity of cold with itself
wherever found, when we get it first on the palm and then
on the cheek, some difference comes, which keeps the two
experiences for ever asunder.''^
* Of the anatomical and physiological conditions of these facts we know
as yet but liltle, and that little need not here be discussed. Two principal
hypotheses have been invoked in the case of the retina. Wundt (Men
THE PERCEPTION OF SPACE. 167
And now let us revert to the query propounded a
moment since : Can these differeifwes of mere quality in feeling ,
varying according to locality yet having each sensibly and in-
trinsically and by itself nothing to do with position, constitute
the * susceptibilities ' ive mentioned, the conditions of being per-
ceived in position, of the localities to which they belong ? The
numbers on a row of houses, the initial letters of a set of
words, have no intrinsic kinship with points of space, and
yet they are the conditions of our knowledge of where any
house is in the row, or any word in the dictionary. Can the
modifications of feeling in question be tags or labels of this
kind which in no wise originally reveal the position of the
spot to which they are attached, but guide us to it by what
Berkeley would call a * customary tie ' ? Many authors have
unhesitatingly replied in the affirmative ; Lotze, who in his
Medizinische Psychologies first described the sensations in
this way, designating them, thus conceived, as local-sign^.
This term has obtained wide currency in Germany, and in
speaking of the * local-sign theory ' hereafter, I shall always
mean the theory which denies that there can be in a sensation any
element of Ojctual locality, of inherent spatial order, any tone as
schen- u. Thierseele, i. 214) called attention to the changes of color-sensibility
which the retina displays as the image of the colored object passes from the
fovea to the periphery. The color alters and becomes darker, and the
change is more rapid in certain directions than in others. This alteration
in general, however, is one of which, as such, we are wholly unconscious.
We see the sky as bright blue all over, the modifications of the blue sensa-
tion being interpreted by us, not as differences in the objective color, but
as distinctions in its locality. Lotze (Medizinische Psychologic, 333, 355), on
the other hand, has pointed out the peculiar tendency which each particu-
lar point of the retina has to call forth that movement of the eyeball which
will carry the image of the exciting object from the point in question to
ihe fovea. With each separate tendency to movement (as with each actual
movement) we may suppose a peculiar modification of sensibility to be
conjoined. This modification would constitute the peculiar local tingeing
of the im^ge by each point. See also Sully's Psychology, pp. 118-121.
Prof. B. Erdman has quite lately (Vierteljahrsschrift f. wiss. Phil., x.
824-9) denied the existence of all evidence for such immanent qualia of
feeling characterizing each locality. Acute as his remarks are, they quite
fail to convince me. On the skin the qualia are evident, I should say.
Where, as on the retina, they are less so (Kries and Auerbach), this may
well be a mere diflSculty of discrimination not yet educated to the
analysis.
* 1862, p. 881.
168 PSYCHOLOGY.
it were which cries to us immediate?!/ and without further
ado, 'I am Acre,' or 'I am there.'
If, as may well be the case, we by this time find our-
selves tempted to accept the Local-sign theory in a general
way, we have to clear up several farther matters. If a sign
is to lead us to the thing it means, we must have some other
source of knowledge of that thing. Either the thing has
been given in a previous experience of which the sign also
formed part — they are associated ; or it is what Reid calls a
' natural ' sign, that is, a feeling which, the first time it
enters the mind, evokes from the native powers thereof a
cognition of the thing that hitherto had lain dormant. In
both cases, however, the sign is one thing, and the thing
another. In the instance that now concerns us, th£, sign is
a quality of feeling and the thing is a position. Now we have
seen that the position of a point is not only revealed, but
created, by the existence of other points to which it stands
in determinate relations. If the sign can by any machinery
which it sets in motion evoke a consciousness either of the other
points, or of the relations, or of both, it would seem to fulfil its
function, and reveal to us the position we seek.
But such a machinery is already familiar to us. It is
neither more nor less than the law of habit in the nervous
system. When any point of the sensitive surface has been
frequently excited simultaneously with, or immediately
before or after, other points, and afterwards comes to be
excited alone, there will be a tendency for its perceptive
nerve-centre to irradiate into the nerve-centres of the other
points. Subjectively considered, this is the same as if we
said that the peculiar feeling of the first point suggests the
feding of the entire region with whose stimulation its own ex-
citement has been habitually associated.
Take the case of the stomach. When the epigastrium
is heavily pressed, when certain muscles contract, etc., the
stomach is squeezed, and its peculiar local sign awakes in
consciousness simultaneously with the local signs of the
other squeezed parts. There is also a sensation of total
vastness aroused by the combined irritation, and somewhere
in this the stomach-feeling seems to lie. Suppose that
later a pain arises in the stomach from some non-mechani-
THE PERCEPTION OF SPACE. 159
cal cause. It will be tinged by the gastric local sign, and
the nerve-centre supporting this latter feeling will excite
the centre supporting the dermal and muscular feelings
habitually associated with it when the excitement was
mechanical. From the combination the same peculiar
vastness will again arise. In a word, * something ' in the
stomach- sensation * reminds ' us of a total space, of which
the diaphragmatic and epigastric sensations also form a
part, or, to express it more briefly still, suggests the neigh-
borhood of these latter organs."^
Eevert to the case of two excited points on a surface with
an unexcited space between them. The general result of
previous experience has been that when either point was
impressed by an outward object, the same object also
touched the immediately neighboring parts. Each point,
together with its local sign, is thus associated with a circle
of surrounding points, the association fading in strength as
the circle grows larger. Each will revive its own circle ;
but when both are excited together, the strongest revival
will be that due to the combined irradiation. Now the tract
joining the two excited points is the only part common to the
two circles. And the feelings of this whole tract will there-
fore awaken with considerable vividness in the imagination
when its extremities are touched by an outward irritant.
The mind receives with the impression of the two distinct
points the vague idea of a line. The twoness of the points
comes from the contrast of their local signs : the line comes
from the associations into which experience has wrought
these latter. If no ideal line arises we have duality with-
out sense of interval ; if the line be excited actually rather
* Maybe the localization of intracranial pain is itself due to such asso-
ciation as this of local signs with each other, rather than to their qualita-
tive similarity in neighboring parts {supra, p. 19); though it is conceivable
that association and similarity itself should here have one and the same
neural basis. If we suppose the sensory nerves from those parts of the
body beneath any patch of skin to terminate in the same sensorial brain-
tract as those from the skin itself, and if the excitement of any one fibre
tends to irradiate through the whole of that tract, the feelings of all fibres
going to that tract would presumabl}^ both have a similar intrinsic quality,
and at the same time tend each to arouse the other. Since the same nerve-
trunk in most cases supplies the skin and the parts beneath, the anatomical
hypothesis presents nothing improbable.
160 PBYCHOLOOT.
than ideally, we have the interval given with its ends, in
the form of a single extended object felt. E. H. Weber, in
the famous article in which he laid the foundations of all
our accurate knowledge of these subjects, laid it down as
the logical requisite for the perception of two separated points,
that the mind should, along with its conscioicsn^ss of them, be-
come aware of an unexcited interval as suxih. I have only tried
to show how the known laws of experience may cause this requi-
site to he fulfilled. Of course, if the local signs of the entire
region offer but little qualitative contrast inter se, the line
suggested will be but dimly defined or discriminated in
length or direction from other possible lines in its neighbor-
hood. This is what happens in the back, where conscious-
ness can sunder two spots, whilst only vaguely apprehend-
ing their distance and direction apart.
The relation of position of the two points is the sug-
gested interval or line. Turn now to the simplest case,
that of a single excited spot. How can it suggest its position ?
Not by recalling any particular line unless experience have
constantly been in the habit of marking or tracing some one
line from it towards some one neighboring point. Now
on the back, belly, viscera, etc., no such tracing habitually
occurs. The consequence is that the only suggestion is
that of the whole neighboring circle ; i.e., the spot simply
recalls the general region in which it happens to lie. By a pro-
cess of successive construction, it is quite true that we can
also get the feeling of distance between the spot and some
other particular spot. Attention, by reinforcing the local
sign of one part of the circle, can awaken a new circle
round this part, and so de proche en proche we may slide our
feeling down from our cheek, say, to our foot. But when
we first touched our cheek we had no consciousness of the
foot at all.* In the extremities, the lips, the tongue and
other mobile parts, the case is different. We there have
an instinctive tendency, when a part of lesser discriminative
* Unless, indeed, the foot happen to be spontaneously tingling or some-
thing of the sort at the moment. The whole surface of the body is always
in a state of semi-conscious irritation which needs only the emphasis of
attention, or of some accidental inward irritation, to become strong at any
point.
THE PERCEPTION OF SPACE. 161
sensibility is touched, to move the member so that the
touching object glides along it to the place where sensi-
bility is greatest. If a body touches our hand we move the
hand over it till the finger-tips are able to explore ii If
the sole of our foot touches anything we bring it towards
the toes, and so forth. There thus arise lines of habitual
passage from all points of a member to its sensitive tip.
These are the lines most readily recalled when any point
is touched, and their recall is identical with the conscious-
ness of the distance of the touched point from the ' tip.' I
think anyone must be aware when he touches a point of
his hand or wrist that it is the relation to the finger-tips of
which he is usually most conscious. Points on the fore-
arm suggest either the finger-tips or the elbow (the latter
being a spot of greater sensibility*). In the foot it is the
toes, and so on. A point can only be cognized in its rela-
tions to the entire body at once by awakening a visual
image of the whole body. Such awakening is even more
obviously than the previously considered cases a matter of
pure association.
This leads us to the eye. On the retina the fovea and the
yellow spot about it form a focus of exquisite sensibility,
towards which every impression falling on an outlying por-
tion of the field is moved by an instinctive action of the
muscles of the eyeball. Few persons, until their attention
is called to the fact, are aware how almost impossible it is
to keep a conspicuous visible object in the margin of the
field of view. The moment volition is relaxed we find that
without our knowing it our eyes have turned so as to bring
it to the centre. This is why most persons are unable tc
keep the eyes steadily converged upon a point in space with
nothing in it. The objects against the walls of the room
* It is true that the inside of the fore- arm, though its discriminative
sensibility is often less than that of the outside, usually rises very promi-
nently into consciousness when the latter is touched. Its cpsthetic sensi-
bility to contact is a good deal finer. We enjoy stroking it from the ex-
tensor to the flexor surface around the ulnar side more than in the reverse
direction. Pronating movements give rise to contacts in this order, and
are frequently indulged in when the back of the fore-arm feels an object
against it.
1(» PSTCHOLOQT.
invincibly attract the fovese to themselves. If we contem-
plate a blank wall or sheet of paper, we always observe in
a moment that we are directly looking at some speck upon it
which, unnoticed at first, ended by 'catching our eye.' Thus
whenever an image falling on the point P of the retina excites
attention, it more habitually moves from that point towards the
fovea than in any one other direction. The line traced thus by
the image is not always a straight line. When the direction
of the point from the fovea is neither vertical nor horizon-
tal but oblique, the line traced is often a curve, with its con-
cavity directed upwards if the direction is upwards, down-
wards if the direction is downwards. This may be verified
by anyone who will take the trouble to make a simple ex-
periment with a luminous body like a candle-flame in a dark
enclosure, or a star. Gazing first at some point remote
from the source of light, let the eye be suddenly turned full
upon the latter. The luminous image will necessarily fall
in succession upon a continuous series of points, reaching
from the one first affected to the fovea. But by virtue of
the slowness with which retinal excitements die away, the
entire series of points will for an instant be visible as an
after-image, displaying the above peculiarity of form ac-
cording to its situation.''^ These radiating lines are neither
regular nor invariable in the same person, nor, probably,
equally curved in different individuals. We are incessant-
ly drawing them between the fovea and every point of the
field of view. Objects remain in their peripheral indistinct-
ness only so long as they are unnoticed. The moment we
attend to them they grow distinct through one of these mo-
tions — which leads to the idea prevalent among uninstructed
persons that we see distinctly all parts of the field of view
at once. The result of this irwessant tracing of radii is that
whenever a local sign P is awakened by a spot of light falling
upon itf it recalls forthwith, even though the eyeball be unmoved,
the local signs of all the other points ivhich lie between P and
the fovea. It recalls them in imaginary form, just as the
normal reflex movement would recall them in vivid form ;
and with their recall is given a consciousness more or less
* These facts were first noticed by Wundt: see his Beitrage, p, 140, 203
See also Lamansky, Pfltiger's Archiv, xi. 418.
THE PSnCBPTION OF SPACE. 163
faint of the whole line on which they lie. In other words,
no ray of light can fall on any retinal spot without the lo-
cal sign of that spot revealing to us, by recalling the line
of its most habitual associates, its direction and distance
from the centre of the field. The fovea acts thus as the
origin of a system of polar co-ordinates, in relation to which
each and every retinal point has through an incessantly-re-
peated process of association its distance and direction de-
termined. Were P alone illumined and all the rest of the
field dark we should still, even with motionless eyes, know
whether P lay high or low, right or left, through the ideal
streaky different from all other streaks, which P alone
has the power of awakening.*
* So far all has been plain sailing, but our course begins to be so tortu-
ous when we descend into minuter detail that I will treat of the more pre-
cise determination of locality in a long note. When P recalls an ideal line
leading to the fovea the line is felt in its entirety and but vaguely ; whilst
P, which we supposed to be a single star of actual light, stands out in strong
distinction from it. The ground of the distinction between P and the
ideal line which it terminates is manifest— P being vivid while the line is
faint ; hut why should P Twld the particular 'position it does, at the end of the
line, rather than anywhere else— for exampU, in its middle? That seems
something not at all manifest.
To clear up our thoughts about this latter mystery, let us take the case
of an actual line of light, none of whose parts is ideal. The feeling of
the line is produced, as we know, when a multitude of retinal points are
excited together, each of which when excited separately would give rise to
one of the feelings called local signs. Each of these signs is the feeling of
a small space. From their simultaneous arousal we might well suppose a
feeling of larger space to result. But why is it necessary that in this
larger spaciousness the sign a should appear always at one end of the line,
z at the other, and m in the middle ? For though the line be a unitary
streak of light, its several constituent points can nevertheless break out
from it, and become alive, each for itself, under the selective eye of atten-
tion.
The uncritical reader, giving his first careless glance at the subject, will
say that there is no mystery in this, and that * of course ' local signs must
appear alongside of each other, each in its own place; — there is no other
way possible. But the more philosophic student, whose business it is to
discover difficulties quite as much as to get rid of them, will reflect that it
is conceivable that the partial factors might fuse into a larger space, and
yet not each be located within it any more than a voice is located in a
chorus He will wonder how, after combining into the line, the points
can become severally alive again : the separate pufCs of a ' sirene ' no longer
strike the ear after they have fused into a certain pitch of sound. He will
recall the fact that when, after looking at things with one eye closed, we
164 P87Cn0L0QT.
And with this we can close the first great division oi
our subject. We have shown that, within the range of
double, by opening the other eye, the number of retinal points affected,
the new retinal sensations do not as a rule appear alongside of the
old ones and additional to them, but merely make the old ones seem
larger and nearer. Why should the affection of new points on the same
retina have so different a result? In fact, he will see no sort of logical
connection between (1) the original separate local signs, (2) the line as a
unit, (3) the line with the points discriminated in it, and (4) the various
nerve-processes which subserve all these different things. He will suspect
our local sign of being a very slippery and ambiguous sort of creature.
Positionless at first, it no sooner appears in the midst of a gang of compan-
ions than it is found maintaining the strictest position of its own, and as-
signing place to each of its associates. How is this possible V Must we
accept what we rejected a while ago as absurd, and admit the points each
to have position in se ? Or must we suspect that our whole construction
has been fallacious, and that we have tried to conjure up, out of association,
qualities which the associates never contained?
There is no doubt a real difficulty here; and the shortest way of dealing
with it would be to confess it insoluble and ultimate. Even if position be
not an intrinsic character of any one of those sensations we have called
local signs, we must still admit that there is something about every one of
them that stands for the potentiality of position, and is the ground why the
local sign, when it gets placed at all, gets placed 7iere rather than there. If this
' something ' be interpreted as a physiological something, as a mere nerve-
process, it is easy to say in a blank way that when it is excited alone, it is
an ' ultimate fact ' (1) that a positionless spot will appear; that when it is
excited together with other similar processes, but without ,the process of
discriminative attention, it is another 'ultimate fact ' (2) that a unitary line
will come; and that the final 'ultimate fact' (3) is that, when the nerve-
process is excited in combination with that other process which subserves
the feeling of attention, what results will be the line with the local sign
inside of it determined to a particular place. Thus we should escape the
responsibility of explaining, by falling back on the everlasting inscruta-
bility of the psycho-neural nexus. The moment we call the ground of lo-
calization physiological, we need only point out how, in those cases in
which localization occurs, the physiological process differs from those in
which it does not, to have done all we can possibly do in the matter. This
would be unexceptionable logic, and with it we might let the matter drop,
satisfied that there was no self-contradiction in it, but only the universal
psychological puzzle of how a new mode of consciousness emerges when-
ever a fundamentally new mode of nervous action occurs.
But, blameless as such tactics would logically be on our part, let us see
whether we cannot push our theoretic insight a little farther. It seems to
me we can. We cannot, it is true, give a reason why the line we feel when
process (2) awakens should have its own peculiar shape; nor can we explain
the essence of the process of discriminative attention. But we can see
why, if the brute facts be admitted that a line may have one of its parts
singled out by attention at all, and that that part may appear in relation to
i
THE PERCEPTION OF SPACE. 165
every sense, experience takes ah initio the spatial form. We
have also shown that in the cases of the retina and skin
other parts at all, the relation must be in the line itself, — for the line and
the parts are the only things supposed to be in consciousness. And we can
furthermore suggest a reason why parts appearing thus in relation to each
other in a line should fall into an immutable order, and each within that
order keep its characteristic place.
If a lot of such local signs all have any quality which evenly augments
as we pass from one to the other, we can arrange them in an ideal serial
order, in which any one local sign must lie below those with more, above
those with less, of the quality in question. It must divide the series into
two parts, — unless indeed it have a maximum or minimum of the quality,
when it either begins or ends it.
Such an ideal series of local signs in the mind is, however, not yet iden-
tical with the feeling of a line in space. Touch a dozen points on the skin
successively, and there seems no necessary reason why the notion of a defi-
nite line should emerge, even though we be strongly aware of a gradation
of quality among the touches. We may of course symbolically arrange
them in a line in our thought, but we can always distinguish between a
line symbolically thought and a line directly felt.
But note now the peculiarity of the nerve-processes of all these local
signs: though they may give no line when excited successively, when ex-
cited together they do give the actual sensation of a line in space. The
sum of them is the neural process of that line; the sum of their feelings
is the feeling of that line; and if we begin to single out particular points
from the line, and notice them by their rank, it is impossible to see how
this rank can appear except as an actual fixed space-position sensibly felt
as a bit of the total line. The scale itself appearing as a line, rank in it
must appear as a definite part of the line. If the seven notes of an octave,
when heard together, appeared to the sense of hearing as an outspread
line of sound — which it is needless to say they do not — why then no one
note could be discriminated without being localized, according to its pitch,
in the line, either as one of its extremities or as some part between.
But not alone the gradation of their quality arranges the local-sign
feelings in a scale. Our momments arrange them also in a ^me-scale.
Whenever a stimulus passes from point a of the skin or retina to point/,
it awakens the local-sign feelings in the perfectly definite time-order abcdef.
It cannot excite/ until cde have been successively aroused. The feeling c
sometimes is preceded by ah, sometimes followed by ha, according to the
movement's direction; the result of it all being that we never feel either a,
c, or/ without there clinging to it faint reverberations of the various time-
orders of transition in which, throughout past experience, it has been
aroused. To the local sign a there clings the tinge or tone, the penumbra
or fringe, of the transition hcd. To/ to c, there cling quite different tones.
Once admit the principle that a feeling may be tinged by the reproductive
consciousness of an habitual transition, even when the transition is not
made, and it seems entirely natural to admit that, if the transition be habit-
ually in the order abcdef, and if a, c, and/ be felt separately at all, a will
be felt with an essential earliness, /with an essential lateness, and that e will
166 PHTCHOLOQY.
every sensible total may be subdivided by discriminative
attention into sensible parts, which are also spaces, and
into relations between the parts, these being sensible spaces
too. Furthermore, we have seen (in a foot-note) that differ-
ent parts, once discriminated, necessarily fall into a deter-
minate order, both by reason of definite gradations in their
quality, and by reason of the fixed order of time-succes-
sion in which movements arouse them. But in all this
nothing has been said of the comparative measurement of
one sensible space-total against another, or of the way
in which, by summing our divers simple sensible space-
experiences together, we end by ronstructing what we re-
gard as the unitary, continuous, and infinite objective Space
of the real world. To this more difficult inquiry we next
pass.
THE CONSTBUCTION OF *KEAL' SPACE,
The problem breaks into two subordinate problems .
(1) How is the subdivision and measurement of the several
sensorial spaces completely effected? and
(2) How do their mutual addition and fusion and reduction
to the same scale, in a ivord, how does their synthesis, occur ?
I think that, as in the investigation just finished, we
found ourselves able to get along without invoking any data
but those that pure sensibility on the one hand, and the
ordinary intellectual powers of discrimination and recollec-
fall between. Thus those psychologists who set little store by local signs
and great store by movements in explaining space-perception, would have
a perfectly definite time-order, due to motion, by which to account for
the definite order of positions that appears when sensitive spots are excited
all at once. Without, however, the preliminary admission of the ' ulti-
mate fact ' that this collective excitement shall feel like a line and nothing
else, it can never be explained why the new order should needs be an
order of positions, and not of merely ideal serial rank. We shall hereafter
have any amount of opportunity to observe how thoroughgoing is the par-
ticipation of motion in all our spatial measurements. Whether the local
signs have their respective qualities evenly graduated or not, the feelings
of transition must be set down as among the verm causce in localization.
But the gradation of the local signs is hardly to be doubted; so we may be-
lieve ourselves really to possess two sets of reasons for localizing any point
we may happen to distinguish from out the midst of any line or any larger
space.
THE PBRGEPTION OF 8PA0B. 16T
fcion on the other, were able to yield; so here we shall
emerge from our more complicated quest with the convic-
tion that all the facts can be accounted for on the supposi-
tion that no other mental forces have been at work save
those we find everywhere else in psychology : sensibility,
namely, for the data ; and discrimination, association^
memory, and choice for the rearrangements and combina
tions which they undergo.
1. The Subdivision of the Original Sense-spaces,
How are spatial subdivisions brought to consciousness ?
in other words. How does spatial discrimination occur?
The general subject of discrimination has been treated in
a previous chapter. Here we need only inquire what are
the conditions that make spatial discrimination so much
finer in sight than in touch, and in touch than in hearing,
smell, or taste.
The first great condition is, that different points of the
surface shall differ in the quality of their immanent sensibility ^
that is, that each shall carry its special local-sign. If the
skin felt everywhere exactly alike, a foot-bath could be dis-
tinguished from a total immersion, as being smaller, but
never distinguished from a wet face. The local-signs are
indispensable ; two points which have the same local- sign
will always be felt as the same point. We do not judge
them two unless we have discerned their sensations to be
different."^ Granted none but homogeneous irritants, that
organ would then distinguish the greatest multiplicity of
irritants — would count most stars or compass-points, or
best compare the size of two wet surfaces — whose local
sensibility was the least even. A skin whose sensibility
shaded rapidly off from a focus, like the apex of a boil,
would be better than a homogeneous integument for spatial
perception. The retina, with its exquisitely sensitive fovea,
has this peculiarity, and undoubtedly owes to it a great part
* M. Binet (Revue Philosophique, Sept. 1880, page 291) says we judge
them locally different as soon as their sensations differ enough for us to
distinguish them as qualitatively different when successively excited. Thii
\& not strictly true. Skin- sensations, different enough to be discriminated
»rhen sueeesiiw, may still fuse locally if excited both at once.
168 P8YCHOL007,
of the minuteness with which we are able to subdivide the
total bigness of the sensation it yields. On its periphery
the local differences do not shade off very rapidly, and we
can count there fewer subdivisions.
But these local differences of feeling , so long as the surface
is unexcited from without , are almost null. I canot feel them
by a pure mental act of attention unless they belong to quite
distinct parts of the body, as the nose and the lip, the finger-
tip and the ear ; their contrast needs the reinforcement of
outward excitement to be felt. In the spatial muchness of
a colic — or, to call it by the more spacious-sounding verna-
cular, of a * bellyache ' — one can with difficulty distinguish
the north-east from the south-west corner, but can do so
much more easily if, by pressing one's finger against the
former region, one is able to make the pain there more in-
tense.
The local differenjces require then an adventitious sensa-
tion, superinduced upon them, to awaken the attention. After
the attention has once been awakened in this way, it may
continue to be conscious of the unaided difference ; just aa
a sail on the horizon may be too faint for us to notice until
someone's finger, placed against the spot, has pointed it out
to us, but may then remain visible after the finger has been
withdrawn. But all this is true only on condition that
separate points of the surface may be exclusively stimulated.
If the whole surface at once be excited from without, and
homogeneously, as, for example, by immersing the body in
salt water, local discrimination is not furthered. The local-
signs, it is true, all awaken at once ; but in such multitude
that no one of them, with its specific quality, stands out in
contrast with the rest. If, however, a single extremity be
immersed, the contrast between the wet and dry parts is
strong, and, at the surface of the water especially, the local-
signs attract the attention, giving the feeling of a ring sur-
rounding the member. Similarly, two or three wet spots
separated by dry spots, or two or three hard points against
the skin, will help to break up our consciousness of the
latter's bigness. In cases of this sort, where points re-
ceiving an identical kind of excitement are, nevertheless,
felt to be locally distinct, and the objective irritants are also
THE PERCEPTION OF 8PA0B. 169
judged multiple, — e.g., compass-points on skin or stars on
retina, — the ordinary explanation is no doubt just, and we
judge the outward causes to be multiple because we have
discerned the local feelings of their sensations to be dif-
ferent.
Capacity for partial stirmdation is thus the second condi-
tion favoring discrimination. A sensitive surface which has to
be excited in all its parts at once can yield nothing but a
sense of undivided largeness. This appears to be the case
with the olfactory, and to all intents and purposes with the
gustatory, surfaces. Of many tastes and flavors, even sim-
ultaneously presented, each affects the totality of its re-
spective organ, each appears with the whole vastness given
by that organ, and appears interpenetrated by the rest.*
* It may, however, be said that even iu the tongue there is a determina-
tion of bitter flavors to the back and of acids to the front edge of the organ.
Spices likewise affect its sides and front, and a taste like that of alum
localizes itself, by its styptic effect on the portion of mucous membrane,
which it immediately touches, more sharply than roast pork, for example,
which stimulates all parts alike. The pork, therefore, tastes more spacious
than the alum or the pepper. In the nose, too, certain smells, of which
vinegar may be taken as the type, seem less spatially extended than heavy,
suffocating odors, like musk. The reason of this appears to be that the
former inhibit inspiration by their sharpness, whilst the latter are drawn
into the lungs, and thus excite an objectively larger surface. The asci* p-
tion of height and depth to certain notes seems due, not to any localization
of the sounds, but to the fact that a feeling of vibration in the chest and
tension in the gullet accompanies the singing of a bass note, whilst, when
we sing high, the palatine mucous membrane is drawn upon by the muscles
which move the larynx, and awakens a feeling in the roof of the mouth.
The only real objection to the law of partial stimulation laid down in
the text is one that might be drawn from the organ of hearing; for, ac-
cording to modern theories, the cochlea may have its separate nerve-termini
exclusively excited by sounds of differing pitch, and yet the sounds seem
all to fill a common space, and not necessarily to be arranged alongside of
each other. At most the high note is felt as a thinner, brighter streak
against a darker background. In an article on Space, published in the
Journal of Speculative Philosophy for January, 1879, 1 ventured to suggest
that possibly the auditory nerve termini might be "excited all at once by
sounds of any pitch, as the whole retina would be by every luminous point
if there were no dioptric apparatus affixed." And I added : " Notwith-
standing the brilliant conjectures of the last few years which assign differ,
ent acoustic end-organs to different rates of air-wave, we are still greatly
in the dark about the subject ; and I, for my part, would much more con-
fidently reject a theory of hearing which violated the principles advanced in
170 PSTCUOLOOY.
I should have been willing some years ago to name with»
out hesitation a third condition of discrimination — saying it
would be most developed in that organ which is susceptible
of the most various qualities of feeling. The retina is un-
questionably such an organ. The colors and shades it
perceives are infinitely more numerous than the diversities
of skin -sensation. And it can feel at once white and black,
whilst the ear can in nowise so feel sound and silence. But
the late researches of Donaldson, Blix, and Goldscheider, *
on specific points for heat, cold, pressure, and pain in the
skin ; the older ones of Czermak (repeated later by Klug
in Ludwig's laboratory), showing that a hot and a cold
compass-point are no more easily discriminated as two than
two of equal temperature ; and some unpublished experi-
ments of my own — all disincline me to make much of this
condition now.f There is, however, one quality of sensa-
tbis article than give up those principles for the sake of any hypothesis
hitherto published about either organs of Corti or basilar membrane. "
Professor Rutherford's theory of hearing, advanced at the meeting of the
British Association for 1886, already furnishes an alternative view which
would make hearing present no exception to the space-theory I defend
and which, whether destined to be proved true or false, ought, at any rate
to make us feel that the Helmholtzian theory is probably not the last wore
in the physiology of hearing. Stepano. ff . (Hermann und Schwalbe's Jahres-
bericht, xv. 404, Literature 1886) reports a case in which more than the
upper half of one cochlea was lost without any such deafness to deep notes
on that side as Helmholtz's theory would require,
♦Donaldson, in Mind, x. 399, 577; Goldscheider, in Archiv f. (Anat. u.)
Physiologic; Blix, in Zeitschrift filr Biologic. A good resume may be
found in Ladd's Physiol. Psychology, part ii. chap. iv. §§ 21-23.
f I tried on nine or ten people, making numerous observations on each,
what difference it made in the discrimination of two points to have them
alike or unlike. The points chosen were (1) two large needle-heads, (2)
two screw-heads, and (3) a needle-head and a screw-head. The distance
of the screw-heads was measured from their centres. I found that when
the points gave diverse qualities of feeling (as in 3), this facilitated the
discrimination, but much less strongly than I expected The difference,
in fact, would often not be perceptible twenty times running When,
however, one of the points was endowed with a rotary movement, the
other remaining still, the doubleness of the points became much more evi-
dent than before. To observe this I took an ordinary pair of compasses with
one point blunt, and the movable leg replaced by a metallic rod which could,
at any moment, be made to rotate in situ by a dentist's drilling-machine, to
which it was attached. The compass had then its points applied to the skin
at such a distance apart as to be felt as one impression. Suddenly rotating
the drill-apparatus then almost always made them seem as two.
THE PERCEPTION OF SPACE. 171
fcion which is particularly exciting, and that is the feding
of motion over any of our surf (ices. The erection of this
into a separate elementary quality of sensibility is one of
the most recent of psychological achievements, and is
worthy of detaining us a while at this point.
The Sensation of Motion over Surfox:es,
The feeling of motion has generally been assumed by
physiologists to be impossible until the positions of terminus
a quo and terminus ad quem are severally cognized, and the
successive occupancies of these positions by the moving
body are perceived to be separated by a distinct interval of
time.* As a matter of fact, however, we cognize only the
very slowest motions in this way. Seeing the hand of a
clock at XII and afterwards at VI, we judge that it has
moved through the interval. Seeing the sun now in the
east and again in the west, I infer it to have passed over
my head. But we can only infer that which we already
generically know in some more direct fashion, and it is ex-
perimentally certain that we have the feeling of motion
given us as a direct and simple sensation. Czermak long ago
pointed out the difference between seeing the motion of the
second-hand of a watch, when we look directly at it, and
noticing the fact of its having altered its position when we
fix our gaze upon some other point of the dial-plate. In
the first case we have a specific quality of sensation which
is absent in the second. If the reader will find a portion
of his skin — the arm, for example — where a pair of com-
pass-points an inch apart are felt as one impression, and if
he will then trace lines a tenth of an inch long on that spot
with a pencil-point, he will be distinctly aware of the point's
motion and vaguely aware of the direction of the motion.
The perception of the motion here is certainly not derived
from a pre-existing knowledge that its starting and ending
points are separate positions in space, because positions in
space ten times wider apart fail to be discriminated as such
* This is only another example of what I call ' the psychologist's fal-
lacy '—thinking that the mind he is studying must necessarily be conscious
of the object after the fashion in which the psychologist himself is con-
scious of it.
172 PaTOHOLOOT.
when excited by the dividers. It is the same with the
retina. One's fingers when cast upon its peripheral portions
cannot be counted — that is to say, the five retinal tracts
which they occupy are not distinctly apprehended by the
mind as five separate positions in space — and yet the slight-
est movement of the fingers is most vividly perceived as
movement and nothing else. It is thus certain that our
sense of movement, being so much more delicate than our
sense of position, cannot possibly be derived from it. A
curious observation by Exner * completes the proof that move-
ment is a primitive form of sensibility, by showing it to be
much more delicate than our sense of succession in time.
This very able physiologist caused two electric sparks to
appear in rapid succession, one beside the other. The
observer had to state whether the right-hand one or the
left-hand one appeared first. When the interval was re-
duced to as short a time as 0.044'^ the discrimination of
temporal order in the sparks became impossible. But
Exner found that if the sparks were brought so close to-
gether in space that their irradiation-circles overlapped, the
eye then felt their flashing as if it were the motion of a
single spark from the point occupied by the first to the
point occupied by the second, and the time-interval might
then be made as small as 0.015'' before the mind began to
be in doubt as to whether the apparent motion started
from the right or from the left. On the skin similar ex-
periments gave similar results.
Vierordtf at almost the same time,\ called atttention to cer-
tain persistent illusions, amongst ivhich are these : If another
person gently trace a line across our wrist or finger, the
latter being stationary, it will feel to us as if the mem-
ber were moving in the opposite direction to the tracing
point. If, on the contrary, we move our limb across a fixed
point, it will be seen as if the point were moving as well.
If the reader will touch his forehead with his forefinger
kept motionless, and then rotate the head so that the skin
of the forehead passes beneath the finger's tip, he will have
*Sitzb. der. k. Akad. Wien, Bd. lxxii., Abth. 3 (1876).
t Zeitschrift ftir Biologic, xii. 226 (1876).
THE PBROEPTION OF SPACE, 173
an irresistible sensation of the latter being itself in motion
in the opposite direction to the head. So in abducting the
fingers from each other ; some may move and the rest be still
still, but the still ones will feel as if they were actively sep-
arating from the rest. These illusions, according to Vierordt,
are survivals of a primitive form of perception, when
motion was felt as such, but ascribed to the whole content
of consciousness, and not yet distinguished as belonging ex-
clusively to one of its parts. When our perception is fully
developed we go beyond the mere relative motion of thing
and ground, and can ascribe absolute motion to one of these
components of our total object, and absolute rest to another.
When, in vision for example, the whole background moves
together, we think that it is ourselves or our eyes which
are moving ; and any object in the foreground which may
move relatively to the background is judged by us to be
still. But primitively this discrimination cannot be per-
fectly made. The sensation of the motion spreads over all
that we see and infects it. Any relative motion of object
and retina both makes the object seem to move, and makes
us feel ourselves in motion. Even now when our whole ob-
ject moves we still get giddy ; and we still see an apparent
motion of the entire field of view, whenever we suddenly
jerk our head and eyes or shake them quickly to and fro.
Pushing our eyeballs gives the same illusion. We know in
all these cases what really happens, but the conditions are
unusual, so our primitive sensation persists unchecked. So
it does when clouds float by the moon. We know the moon
is still ; but we see it move even faster than the clouds.
Even when we slowly move our eyes the primitive sensation
persists under the victorious conception. If we notice
closely the experience, we find that any object towards
which we look appears moving to meet our eye.
But the most valuable contribution to the subject is
the paper of G. H. Schneider,* who takes up the matter
zoologically, and shows by examples from every branch of
the animal kingdom that movement is the quality by which
animals most easily attract each other's attention. The in-
* Vierteljabrsch. ftir wiss. Philos., n. 877.
174 P8YCH0L0OT.
stinct of * shamming death * is no shamming of death at all
but rather a paralysis through fear, which saves the insect,
crustacean, or other creature from being noticed at all by his
enemy. It is parallelled in the human race by the breath-
holding stillness of the boy playing ' I Si)y,' to whom the
seeker is near ; and its obverse side is shown in our invol-
untary waving of arms, jumping up and down, and so forth,
when we wish to attract someone's attention at a distance.
Creatures * stalking ' their prey and creatures hiding from
their pursuers alike show how immobility diminishes con-
spicuity. In the woods, if we are quiet, the squirrels and
birds will actually touch us. Flies will light on stuffed
birds and stationary frogs.* On the other hand, the tre-
mendous shock of feeling the thing we are sitting on begin
to move, the exaggerated start it gives us to have an insect
unexpectedly pass over our skin, or a cat noiselessly come
and snuffle about our hand, the excessive reflex effects of
tickling, etc., show how exciting the sensation of motion is
per se. A kitten cannot help 'pursuing a moving ball. Im-
pressions too faint to be cognized at all are immediately
felt if they move. A fly sitting is unnoticed, — we feel it the
moment it crawls. A shadow may be too faint to be per-
ceived. As soon as it moves, however, we see it. Schneider
found that a shadow, with distinct outline, and directly fix-
ated, could still be perceived when moving, although its
objective strength might be but half as great as that of a
stationary shadow so faint as just to disappear. With a
blurred shadow in indirect vision the difference in favor
of motion was much greater — namely, 13.3 : 40.7. If we
hold a finger between our closed eyelid and the sunshine
we shall not notice its presence. The moment we move it
to and fro, however, we discern it. Such visual perception
as this reproduces the conditions of sight among the
radiates, t
* Exner tries to show that the structure of the faceted eye of articulates
adapts it for perceiving motions almost exclusively.
f Schneider tries to explain why a sensory surface is so much more ex-
cited when its impression moves. It has long since been noticed how much
more acute is discrimination of successive than of simultaneous differences.
But in the case of a moving impression, say on the retina, we have a suic
THE PERCEPTION OF SPACE. 176
Enough has now been said to show that in the ediwation
of spatial discrimination the motions of impressions across sen-
sory surfaces must have been the principal agent in breaking
up our consciousness of the surfaces into a consciousness
of their parts. Even to-day the main function of the pe-
ripheral regions of our retina is that of sentinels, which,
when beams of light move over them, cry * Who goes there ? '
and call the fovea to the spot. Most parts of the skin do
but perform the same office for the finger-tips. Of course
finger-tips and fovea leave some power of direct perception
to marginal retina and skin respectively. But it is worthy
of note that such perception is best developed on the skin of
the most movable parts (the labors of Vierordt and his
pupils have well shown this) ; and that in the blind, whose
skin is exceptionally discriminative, it seems to have become
so through the inveterate habit which most of them possess
of twitching and moving it under whatever object may
touch them, so as to become better acquainted with the con-
formation of the same. Czermak was the first to notice this.
It may be easily verified. Of course movement of surface
under object is {for purposes of stimulation) equivalent to move-
ment of object over surface. In exploring the shapes and
mation of both sorts of difference ; whereof the natural effect must be to
produce the most perfect discrimination of all.
ri
Fig. 53.
In the left-hand figure let the dark spot B move, for example, from
right to left. At the outset there is the simultaneous contrast of black and
white in B and A. When the motion has occurred so that the right-hand
figure is produced, the same contrast remains, the black and the white
having changed places. But in addition to it there is a double suc-
cessive contrast, first in A, which, a moment ago white, has now become
black ; and second in B, which, a moment ago black, has now become
white. If we make each single feeling of contrast = 1 (a supposition tar
too favorable to the state of rest), the sum of contrasts in the case of motion
will be 3, as against 1 in the state of rest. That is, our attention will be
called by a treble force to the difference of color, provided the color be-
gin to move.— (Cf. also Fleischl, Physiologiscne Optische Notizen, 2te
Mittheilung, Wiener Sitzunpberichte, 1888.)
176 P8TCH0L00T.
sizes of things by either eye or skin the movements of these
organs are incessant and unrestrainable. Every such move-
ment draws the points and lines of the object across the
surface, imprints them a hundred times more sharply,
and drives them home to the attention. The immense part
thus played by movements in our perceptive activity is held
by many psychologists^ to prove that the muscles are them-
selves the space-perceiving organ. Not surface-sensibility,
but * the muscular sense,' is for these writers the original
and only revealer of objective extension. But they have
all failed to notice with what peculiar intensity muscular
contractions call surface-sensibilities into play, and that the
mere discrimination of impressions (quite apart from any
question of measuring the space between them) largely
depends on the mobility of the surface upon which they
fall, t
* Brown, Bain, J. 8. Mill, and in a modified manner Wundt. Helmholtz.
Sully, etc.
fM. Ch. Dunan, in his forcibly written essay ' 1 Kspace Visiiel et
I'Espace Tactile ' in the Revue Philosophique for 1888, endeavors to prove
that surfaces alone give no perception of extent, by citing the way in
which the blind go to work to gain an idea of an object's shape. If surfaces
were the percipient organ, he says, " both the seeing and the blind ought
to gain an exact idea of the size (and shape) of an object by merely laying
their hand flat upon it (provided of course that it were smaller than the
hand), and this because of their direct appreciation of the amount of tactile
surface affected, and with no recourse to the muscular sense. . . . But the
fact is that a person born blind never proceeds in this way to measure ob-
jective surfaces. The only means which he has of getting at the size of a
body is that of running his finger along the lines by which it is bounded.
For instance, if you put into the hands of one born blind a book whose
dimensions are unknown to him, he will begin by resting it against his
chest so as to hold it horizontal ; then, bringing his two hands together at
the middle of the edge opposite to the one iigainst his body, he will draw
them asunder till they reach the ends of the edge in question ; and then,
and not till then, will he be able to say what the length of the object is "
(vol. XXV. p. 148). I think that anyone who will try to appreciate the size
and shape of an object by simply * laying his hand flat upon it ' will find
that the great obstacle is that he feels the contours so imperfectly. The
moment, however, the hands move, the contours are emphatically and dis-
tinctly felt. All perception of shape and size is perception of contours, and
first of all these must be made sharp. Motion does this ; and the impulse
to move our organs in perception is primarily due to the craving which we
leel to get our surface-sensations sharp. When it comes to the naming and
THE PERCEPTION OF SPACE. Ill
2. The Measurement of the sense-spaces against each other.
What precedes is all we can say in answer to the problem
of discrimination. Turn now to that of measurement of the
several spaces against each other, that being the first step
in our constructing out of our diverse space-experiences the
one space we believe in as that of the real world.
The first thing that seems evident is that we have no
immediate power of comparing together with any accuracy
the extents revealed by different sensations. Our mouth-
cavity feels indeed to itself smaller, and to the tongue
larger, than it feels to the finger or eye, our tympanic
membrane feels larger than our finger-tip, our lips feel
larger than a surface equal to them on our thigh. So much
comparison is immediate ; but it is vague ; and for anything
exact we must resort to other help.
The great agent in comparing the extent felt by one sensory
surface iviih that felt by another y is superposition — superposition
of one surface upon anotlwr, and superposition of one outer
thing upon many surfaces. Thus are exact equivalencies and
common measures introduced, and the way prepared for
numerical results.
Could we not superpose one part of our skin upon an-
other, or one object on both parts, we should hardly suc-
ceed in coming to that knowledge of our own form which
we possess. The original differences of bigness of our dif-
ferent parts would remain vaguely operative, and we should
have no certainty as to how much lip was equivalent to so
much forehead, how much finger to so much back.
But with the power of exploring one part of the surface
by another we get a direct perception of cutaneous equiva-
lencies. The primitive differences of bigness are over-
powered when we feel by an immediate sensation that a
certain length of thigh- surface is in contact with the entire
palm and fingers. And when a motion of the opposite finger-
tips draws a line first along this same length of thigh and
measuring of objects in terms of some common standard we shall see pres-
ently how movements help also ; but no more in this case than the other
do they help, because the quality of extension itself is contributed by the
'muicular sense.'
178 PSYCHOLOGY,
then along the whole of the hand in question, we get a new
manner of measurement, less direct but confirming the
equivalencies established by the first. In these ways, by
superpositions of parts and by tracing lines on different
parts by identical movements, a person deprived of sight
can soon learn to reduce all the dimensions of his body to a
homogeneous scale. By applying the same methods to
objects of his own size or smaller, he can with equal ease
make himself acquainted with their extension stated in
terms derived from his own bulk, palms, feet, cubits, spans,
paces, fathoms (armspreads), etc. In these reductions it is
to be noticed that wh^n the. resident sensations of largeness
of two opposed surfaces conflict^ one of the sensations is chosen
as the trite standard and the other treated as illusory. Thus
an empty tooth-socket is believed to be really smaller than
the finger-tip which it will not admit, although it may/ee/
larger ; and in general it may be said that the hand, as the
almost exclusive organ of palpation, gives its own magnitude
to the other parts, instead of having its size determined by
them. In general, it is, asFechner says, the extent felt by
the more sensitive part to which the other extents are re-
duced. *
But even though exploration of one surface by another
were impossible, we could always measure our various
surfaces against each other by applying the same extended
object first to one and then to another. We should of
course have the alternative of supposing that the object
itself waxed and waned as it glided from one place to
another (cf. above, p. 141) ; but the principle of simplifying
as much as possible our world would soon drive us out of
that assumption into the easier one that objects as a rule
*Fechner describes (Psychophysik, i. 132) a * method of equivalents'
for measuring the sensibility of the skin. Two compasses are used, one on
the part A. another on the part B, of the surface The poiuts on B must
be adjusted so that their distance apart appears equal to that between the
points on A With the place A constant, the second pair of points must be
varied a great deal for every chauge in the place B. though for the same A
and B the relation of the two compasses is remarkably constant, and con-
tinues unaltered for mouths jirovided but few experiments are made on
each day. If, however, we practise daily their difference grows less, in
accordance with the law given in the text
THE PERCEPTION OF SPACE. 179
keep their sizes, and that most of our sensations are
aflected by errors for which a constant allowance must be
made.
In the retina there is no reason to suppose that the
bignesses of two impressions (lines or blotches) falling on
different regions are primitively felt to stand in any exact
mutual ratio. It is only when the impressions come from
the same object that we judge their sizes to be the same.
And this, too, only when the relation of the object to the
eye is believed to be on the whole unchanged. When the
object by moving changes its relations to the eye the sensa-
tion excited by its image even on the same retinal region
becomes so fluctuating that we end by ascribing no absolute
import whatever to the retinal space-feeling which at any
moment we may receive. So complete does this overlook-
ing of retinal magnitude become that it is next to impossi-
ble to compare the visual magnitudes of objects at different
distances without making the experiment of superposition.
We cannot say beforehand how much of a distant house or
tree our finger will cover. The various answers to the
familiar question. How large is the moon ? — answers which
vary from a cartwheel to a wafer — illustrate this most
strikingly. The hardest part of the training of a young
draughtsman is his learning to feel directly the retinal (i.e.
primitively sensible) magnitudes which the different objects
in the field of view subtend. To do this he must recover
what Kuskin calls the ' innocence of the eye ' — that is, a
sort of childish perception of stains of color merely as
such, without consciousness of what they mean.
With the rest of us this innocence is lost. Out of all the
visual magnitudes of each known object we have selected one as
the KEAL one to think of and degraded all the others to serve as
its signs. This * real ' magnitude is determined by aesthetic
and practical interests. It is that which we get when the
object is at the distance most propitious for exact visual
discrimination of its details. This is the distance at which
we hold anything we are examining. Farther than this we
see it too small, nearer too large. And the larger and the
smaller feeling vanish in the act of suggesting this one,
their more important meaning. As I look along the dining-
180 PBTOHOLOGT.
table I overlook the fact that the farther plates and glasses
fed so much smaller than my own, for I know that they are
all equal in size ; and the feeling of them, which is a present
sensation, is eclipsed in the glare of the knowledge, which
is a merely imagined one.
If the inconsistencies of sight-spaces inter se can thus be
reduced, of course there can be no difficulty in equating
sight-spaces with spaces given to touch. In this equation
it is probably the touch-feeling which prevails as real and
the sight which serves as sign — a reduction made necessary
not only by the far greater constancy of felt over seen
magnitudes, but by the greater practical interest which the
sense of touch possesses for our lives. As a rule, things
only benefit or harm us by coming into direct contact with
our skin : sight is only a sort of anticipatory touch ; the
latter is, in Mr. Spencer's phrase, the * mother-tongue of
thought,' and the handmaid's idiom must be translated
into the language of the mistress before it can speak clearly
to the mind.*
Later on we shall see that the feelings excited in the
joints when a limb moves are used as signs of the path
traversed by the extremity. But of this more anon. As
for the equating of sound-, smell-, and taste-volumes with
those yielded by the more discriminative senses, they are
too vague to need any remark. It may be observed of
pain, however, that its size has to be reduced to that of the
normal tactile size of the organ which is its seat. A finger
with a felon on it, and the pulses of the arteries therein, both
* feel ' larger than we believe they really * are. '
* Prof. Jastrow gives as the result of his experiments this general
conclusion (Am. Journal of Psychology, in. 53) : "The space-perceptions
of disparate senses are themselves disparate, and whatever harmony
there is amongst them we are warranted in regarding as the result
of experience. The spacial notions of one deprived of the sense of sight
and reduced to the use of the other space-senses must indeed be different
from our own." But he continues: "The existence of the striking
disparities between our visual and our other space- perceptions without
confusing us, and, indeed, without usually being noticed, can only be
explained by the tendency to interpret all dimensions into ilieir visual
tguitaUnts.*' But this author gives no reasons for saying ' visual ' rather
than ' tactile ;' and I must continue to think that probabilities point the
other way so far as what we call real magnitudes are concerned.
THE PERCEPTION OF 8PAGB. 181
It will have been noticed in the account given that
when two sensorial space-impressions, believed to come from the
same object, differ, then the one most interesting, practically
or cesthetically, is judged to be the true one. This law of
interest holds throughout — though a permanent interest,
like that of touch, may resist a strong but fleeting one like
that of pain, as in the case just given of the felon.
3. The Summation of the Sense-spaces.
Now for the next step in our construction of real space :
How are the various sense-spaces added together into a
consolidated and unitary continuum ? For they are, in man
at all events, incoherent at the start.
Here again the first fact that appears is that primitively
our space-experiences form a chaos, out of ichich we have no
immediate faculty for extricating them. Objects of different
sense-organs, experienced together, do not in the first instance
appear either inside or alongside or far outside of eojch other,
neither spatially continuous nor discontinuous, in any definite
sense of these words. The same thing is almost as true of
objects felt by different parts of the same organ before
discrimination has done its finished work. The most we
can say is that all our space-experiences together form an
objective total and that this objective total is vast.
Even now the space inside our mouth, which is so inti-
mately known and accurately measured by its inhabitant
the tongue, can hardly be said to have its internal direc-
tions and dimensions known in any exact relation to those
of the larger world outside. It forms almost a little world
by itself. Again, when the dentist excavates a small cavity
in one of our teeth, we feel the hard point of his instrument
scraping, in distinctly differing directions, a surface which
seems to our sensibility vaguely larger than the subsequent
use of the mirror tells us it * really ' is. And though the
directions of the scraping differ so completely inter se, not
one of them can be identified with the particular direction
in the outer world to which it corresponds. The space of
the tooth-sensibility is thus really a little world by itself,
which can only become congruent with the outer space-
182 P8TCH0L00T,
world by farther experiences which shall alter its bulk,
identify its directions, fuse its margins, and finally imbed it
as a definite part within a definite whole. And even though
every joint's rotations should be felt to vary inter se as so
many differences of direction in a common room ; even
though the same were true of diverse tracings on the skin,
and of diverse tracings on the retina respectively, it would
still not follow that feelings of direction, on these different
surfaces, are intuitively comparable among each other, or
with the other directions yielded by the feelings of the
semi-circular canals. It would not follow that we should
immediately judge the relations of them all to each other
in one space-world.
If with the arms in an unnatural attitude we *feel'
things, we are perplexed about their shape, size, and
position. Let the reader lie on his back with his arms
stretched above his head, and it will astonish him to find
how ill able he is to recognize the geometrical relations of
objects placed within reach of his hands. But the geomet-
rical relations here spoken of are nothing but identities
recognized between the directions and sizes perceived in
this way and those perceived in the more usual ways.
The two ways do not fit each other intuitively.
How lax the connection between the system of visual and
the system of tactile directions is in man, appears from the
facility with which microscopists learn to reverse the move-
ments of their hand in manipulating things on the stage of
the instrument. To move the slide to the seen left they
must draw it to the felt right. But in a very few days the
habit becomes a second nature. So in tying our cravat,
shaving before a mirror, etc., the right and left sides are
inverted, and the directions of our hand movements are the
opposite of what they seem. Yet this never annoys us.
Only when by accident we try to tie the cravat of another
person do we learn that there are two ways of combining
sight and touch perceptions. Let any one try for the first
time to write or draw while looking at the image of his
hand and paper in a mirror, and he will be utterly bewil-
dered. But a very short training will teach him to undo
in this respect the associations of his previous lifetime.
THE PERGEPTION OF 8PAGB. 183
Prisms show this in an even more striking way. If the
ejes be armed with spectacles containing slightly prismatic
glasses with their bases turned, for example, towards the
right, every object looked at will be apparently translocated
to the left ; and the hand put forth to grasp any such object
will make the mistake of passing beyond it on the left side.
But less than an hour of practice in wearing such spectacles
rectifies the judgment so that no more mistakes are made.
In fact the new-formed associations are already so strong,
that when the prisms are first laid aside again the opposite
error is committed, the habits of a lifetime violated, and
the hand now passed to the right of every object which it
seeks to touch.
The primitive chaos thus subsists to a great degree
through life so far as our immediate sensibility goes. We
feel our various objects and their bignesses, together or in
succession ; but so soon as it is a question of the order and
relations of many of them at once our intuitive apprehension
remains to the very end most vague and incomplete.
Whilst we are attending to one, or at most to two or three
objects, all the others lapse, and the most we feel of them is
that they still linger on the outskirts and can be caught
again by turning in a certain way. Nevertheless throughout
aU this confusion we conceive of a world spread out in a perfectly
fixed and orderly fashion, and we believe in its existence. The
question is : How do this conception and this belief arise ? How
is the chaos smoothed and straightened out ?
Mainly by two operations : Some of the experiences are
apprehended to exist out- and alongside of each other, and
others are apprehended to interpenetrate each other, and
to occupy the same room. In this way what was incoherent
and irrelative ends by being coherent and definitely related ;
nor is it hard to trace the principles, by which the mind is
guided in this arrangement of its perceptions, in detail.
In the first place, following the great intellectual law of
economy, we simplify, unify, and identify as much as we
possibly can. Whatever sensible data can be attended to together
we locate together. Their several extents seem one extent. The
place at which ea^h appears is held to he the same with the place
184 PSYGUOLOOT.
at which the others appear. They become^ in shorty so many
properties of one and the same eeal thing. This is the first
and great commandment, the fundamental ' act ' by which
our world gets spatially arranged.
In this coaJ£scence in a 'thing,' one of the coalescing
sensations is held to be the thing, the other sensations are
taken for its more or less accidental properties, or modes of
appearance.* The sensation chosen to be the thing essen-
tially is the most constant and practically important of the
lot ; most often it is hardness or weight. But the hardness
or weight is never without tactile bulk ; and as we can
always see something in our hand when we feel something
there, we equate the bulk felt with the bulk seen, and thence-
forward this common bulk is also apt to figure as of the
essence of the * thing.' Frequently a shape so figures,
sometimes a temperature, a taste, etc. ; but for the most part
temperature, smell, sound, color, or whatever other phenom-
ena may vividly impress us simultaneously with the bulk
felt or seen, figure among the accidents. Smell and sound
impress us, it is true, when we neither see nor touch the
thing ; but they are strongest when we see or touch, so we
locate the source of these properties within the touched or
seen space, whilst the properties themselves we regard as
overflowing in a weakened form into the spaces filled by
other things. In all this, it loill be observed, the sense-data
whose spaces coalesce into one are yielded by different sense-
organs. Such data have no tendency to displace each other
from consciousness, but can be attended to together all at
once. Often indeed they vary concomitantly and reach a
maximum together. We may be sure, therefore, that the
general rule of our mind is to locate in each other all sensa-
tions which are associated in simultaneous experience, and
do not interfere with each other's perception. f
* Cf. Lipps on * Complication,' Grundtatsachen, etc., p. 579.
f Ventriloquism shows this very prettily. The ventriloquist talks with-
out moving his lips, and at the same time draws our attention to a doll, a
box, or some other object. We forthwith locate the voice within this
object. On the stage an actor ignorant of music sometimes has to sing,
or play on the guitar or violin. He goes through the motions before our
eyes, whilst in the orchestra or elsewhere the music is performed. But
because as we listen we see the actor, it is almost impossible not to hear the
music as if coming from where he sits or stands.
THE PERCEPTION OF SPACE. 186
Different impressions on the same sense-organ do interfere
with each other's perception, and cannot well be attended
to at once. Hence ive do not locate thsm in each other's spaces^
but arrange them in a serial order of exteriority ^ each alongside
of the restf in a space larger than that which any one sensation
brings. This larger space, however, is an object of concep-
tion rather than of direct intuition, and bears all the marks
of being constructed piecemeal by the mind. The blind
man forms it out of tactile, locomotor, and auditory experi-
ences, the seeing man out of visual ones almost exclusively.
As the visual construction is the easiest to understand,
let us consider that first.
Every single visual sensation or * Held of view ' is
limited. To get a new field of view for our object the old
one must disappear. But the disappearance may be only
partial. Let the first field of view be A B C. If we carry
our attention to the limit C, it ceases to be the limit, and
becomes the centre of the field, and beyond it appear fresh
parts where there were none before :^ ABC changes, in
short, to C D E. But although the parts A B are lost to
sight, yet their image abides in the memory ; and if we think
of our first object ABC as having existed or as still existing
at all, we must think of it as it was originally presented,
namely, as spread out from C in one direction just as C D E
is spread out in another. A B and D E can never coalesce
in one place (as they could were they objects of different
senses) because they can never be perceived at once : we
must lose one to see the other. So (the letters standing
now for * things ') we get to conceive of the successive fields
of things after the analogy of the several things which we
perceive in a single field. They must be out- and along-
side of each other, and we conceive that their juxtaposed
spaces must make a larger space. A B C -f- C D E must,
in short, be imagined to exist in the form of A B C D E or
not imagined at all.
We can usually recover anything lost from sight by
moving our attention and our eyes back in its direction ; and
* Cf . Shand, in Mind, xiii. 340.
186 P8YCH0L00Y.
through these constant changes every field of seen things
comes at last to be thought of as always having a fringe
of other things possible to be seen spreading in all directions
round about it. Meanwhile the movements concomitantly
with which the various fields alternate are also felt and re-
membered ; and gradually (through association) this and
that movement come in our thought to suggest this or that
extent of fresh objects introduced. Gradually, too, since
the objects vary indefinitely in kind, we abstract from
their several natures and think separately of their mere
extents, of which extents the various movements remain as
the only constant introducers and associates. More and
more, therefore, do we think of movement and seen extent
as mutually involving each other, until at last (with Bain
and J. S. Mill) we may get to regard them as synonymous,
and say, " What is the meaning of the ivord extent, unless it
be possible movement?"^ We forget in this conclusion
that (whatever intrinsic extensiveness the movements may
appear endowed with), that seen spreadoutness which is
the pattern of the abstract extensiveness which we imagine
came to us originally from the retinal sensation.
The muscular sensations of the eyeball signify this sort
of visible spreadoutness, just as this visible spreadoutness
may come in later experience to signify the ' real ' bulks,
distances, lengths and breadths known to touch and loco-
motion, t To the very end, however, in us seeing men,
the quality, the nature, the sort of thing ive mean by exten-
siveness, would seem to be the sort of feeling which our re-
tinal stimulations bring.
In one deprived of sight the principles by which the
notion of real space is constructed are the same. Skin-
feelings take in him the place of retinal feelings in giving
* See, e.g., Bain's Senses and Intellect, pp. 366-7, 371.
f When, for example, a baby looks at Its own moving hand, it sees
one object at the same time that it feels another. Both interest its
attention, and it locates them together. But the felt object's size is the
more constant size, just as the felt object is, on the whole, the more in-
teresting and important object ; and so the retinal sensations become re-
garded as its signs and have their ' real space- values ' interpreted in
tangible terms.
THE PERCEPTION OF SPACE. 187
the quality of lateral spreadoutness, as our attention passes
from one extent of them to another, awakened by an object
sliding along. Usually the moving object is our hand ;
and feelings of movement in our joints invariably accom-
pany the feelings in the skin. But the feeling of the skin
is what the blind man means by his skin ; so the size of the
skin -feelings stands as the absolute or real size, and the
size of the joint-feelings becomes a sign of these. Suppose,
for example, a blind baby with (to make the description
shorter) a blister on his toe, exploring his leg with his
finger-tip and feeling a pain shoot up sharply the instant
the blister is touched. The experiment gives him four
different kinds of sensation — two of them protracted, two
sudden. The first pair are the movement-feeling in the
joints of the upper limb, and the movement-feeling on
the skin of the leg and foot. These, attended to together,
have their extents identified as one objective space —
the hand moves through the same space in which the
leg lies. The second pair of objects are the pain in the
blister, and the peculiar feeling the blister gives to the
finger. Their spaces also fuse ; and as each marks the end
of a peculiar movement-series (arm moved, leg stroked),
the movement-spaces are emphatically identified with each
other at that end. Were there other small blisters dis-
tributed down the leg, there would be a number of these
emphatic points ; the movement-spaces would be iden-
tified, not only as totals, but point for point. *
*The incoherence of the different primordial sense-spaces inter ae
is often made a pretext for denying to the primitive bodily feelings any
spatial quality at all. Nothing is commoner than to hear it said : "Babies
have originally no spatial perception ; for when a baby's toe aches he does
not place the pain in the toe. He makes no definite movements of defence,
and may be vaccinated without being held." The facts are true enough ;
but the interpretation is all wrong. What really happens is that the baby
does not place his ' toe ' in the pain ; for he knows nothing of his * toe ' as
yet. He has not attended to it as a visual object ; he has not handled it
with his fingers ; nor have its normal organic sensations or contacts yet
become interesting enough to be discriminated from the whole massive
feeling of the foot, or even of the leg to which it belongs. In short, the
toe is neither a member of the babe's optical space, of his hand-movement
space, nor an independent member of his leg-and-foot space. It has ac-
tually no mental existence yet save as this little pain-space. What wonder,
188 PSYCHOLOGY.
Just so with spaces beyond the body's limits. Continn-
ing the joint-feeling beyond the toe, the baby hits another
object, which he can still think of when he brings his hand
back to its blister again. That object at the end of that
joint-feeling means a new place for him, and the more such
objects multiply in his experience the wider does the space
of his conception grow. If, wandering through the woods
to-day by a new path, I find myself suddenly in a glade
which affects my senses exactly as did another I reached
last week at the end of a different walk, I believe the two
identical affections to present the same persisting glade,
and infer that I have attained it by two differing roads.
The spaces walked over grow congruent by their extremi-
ties ; though apart from the common sensation which those
extremities give me, I should be under no necessity of con-
necting one walk with another at all. The case in no whit
differs when shorter movements are concerned. If, moving
first one arm and then another, the blind child gets the
same kind of sensation upon the hand, and gets it again
as often as he repeats either process, he judges that he has
touched the same object by both motions, and concludes
that the motions terminate in a common place. From place
to place marked in this way he moves, and adding the
places moved through, one to another, he builds up his no-
tion of the extent of the outer world. The seeing man's
process is identical ; only his units, which may be succes-
sive bird's-eye views, are much larger than in the case of
the blind.
then, if the pain seem a little space-world all by itself ? But let the pain
once associate itself with these other space-worlds, and its space will be-
come part of their space. Let the baby feel the nurse stroking the
limb and awakening the pain every time her finger passes towards the
toe ; let him look on and see her finger on the toe every time the pain
shoots up ; let him handle his foot himself and get the pain whenever
the toe comes into his fingers or his mouth ; let moving the leg exacerbate
the pain,— and all is changed. The space of the pain becomes identified
with that part of each of the other spaces which gets felt when it
awakens ; and by their identity with it these parts are identified with each
other, and grow systeniatically connected as members of a larger extensive
whole.
THE PERCEPTION OF SPACE. 189
FBBBJINGS IN JOINTS AND FEELINGS IN MUSOLBS.
1. Feelings of Movement in Joints,
I have been led to speak of feelings which arise in
joints. As these feelings have been too much neglected in
Psychology hitherto, in entering now somewhat minutely
into their study I shall probably at the same time freshen
the interest of the reader, which under the rather dry ab-
stractions of the previous pages may presumably have
flagged.
When, by simply flexing my right forefinger on its meta-
carpal joint, I trace with its tip an inch on the palm of my
left hand, is my feeling of the size of the inch purely and
simply a feeling in the skin of the palm, or have the mus-
cular contractions of the right hand and forearm anything
to do with it ? In the preceding pages I have constantly
assumed spatial sensibility to be an affair of surfaces. At
first starting, the consideration of the ' muscular sense ' as
a space-measurer was postponed to a later stage. Many
writers, of whom the foremost was Thomas Brown, in his
Lectures on the Philosophy of the Human Mind, and of whom
the latest is no less a Psychologist than Prof. Delboeuf,*
hold that the consciousness of active muscular motion,
aware of its own amount, is the fons et origo of all spatial
measurement. It would seem to follow, if this theory were
true, that two skin-feelings, one of a large patch, one of a
small one, possess their difference of spatiality, not as an
immediate element, but solely by virtue of the fact that the
large one, to get its points successively excited, demands
more muscular contraction than the small one does. Fixed
associations with the several amounts of muscular contrac*
tion required in this particular experience would thus ex-
* ' Pourquoi . les Sensations visuelles sont elles etendues ? ' in Revue
Philosophique, iv. 167. — As the proofs of this chapter are being corrected,
I receive the third ' Heft ' of Milnsterberg's BeitrSge zur Experimentellen
Psychologie, in which that vigorous young psychologist reaffirms (if I
understand him after so hasty a glance) more radically than ever the doc-
trine that muscular sensation proper is our one means of measuring exten-
sion. Unable to reopen the discussion here, I am in duty bound to call
the attention of the reader to Herr M.'s work.
190 PBYCHOLOOT.
plain the apparent sizes of the skin-patches, which sizes
would consequently not be primitive data but derivative re-
sults.
It seems to me that no evidence of the muscular measure-
mmts in question exists; but that all the facts may be ex-
plained by surface-sensibility, provided we take that of the
joint-surfaces also into account.
The most striking argument, and the most obvious on©,
which an upholder of the muscular theory is likely to pro-
duce is undoubtedly this fact : if, with closed eyes, we trace
figures in the air with the extended forefinger (the motions
may occur from the metacarpal-, the wrist-, the elbow-, or
the shoulder-joint indifferently), what we are conscious of in
each case, and indeed most acutely conscious of, is the
geometric path described by the finger-ftp. Its angles, its
subdivisions, are all as distinctly felt as if seen by the eye ;
and yet the surface of the finger-tip receives no impression
at all.* But with each variation of the figure, the muscular
contractions vary, and so do the feelings which these yield.
Are not these latter the sensible data that make us aware of
the lengths and directions we discern in the traced line ?
Should we be tempted to object to this supposition of
the advocate of perception by muscular feelings, that we
have learned the spatial significance of these feelings by
reiterated experiences of seeing what figure is drawn when
each special muscular grouping is felt, so that in the last
resort the muscular space feelings would be derived from
retinal-surface feelings, our opponent might immediately
hush us by pointing to the fact that in persons born blind
the phenomenon in question is even more perfect than in
ourselves.
If we suggest that the blind may have originally traced
the figures on the cutaneous surface of cheek, thigh, or palm,
and may now remember the specific figure which each pres-
ent movement formerly caused the skin- surface to per-
ceive, he may reply that the delicacy of the motor percep-
* Even if the figure be drawn on a board instead of in the air, the vari-
ations of contact on the finger's surface will be much simpler than the
peculiarities of the traced figure itself.
THE PERCEPTION OF SPACE. 191
tion far exceeds that of most of the cutaneous surfaces ;
that, in fact, we can feel a figure traced only in its differen-
tials, so to speak, — a figure which we merely start to trace by
our finger-tip, a figure which, traced in the same way on our
finger-tip by the hand of another, is almost if not wholly
unrecognizable.
The champion of the muscular sense seems likely to be
triumphant until ive invoke the articular cartilages^ as in-
ternal surfaces whose sensibility is called in play by every
movement we make, however delicate the latter may be.
To establish the part they play in our geometrizing, it
is necessary to review a few facts. It has long been known
by medical practitioners that, in patients with cutaneous
anaesthesia of a limb, whose muscles also are insensible to
the thrill of the faradic current, a very accurate sense of the
way in which the limb may be flexed or extended by the
hand of another may be preserved.* On the other hand,
we may have this sense of movement impaired when the tac-
tile sensibility is well preserved. That the pretended feeling
of outgoing innervation can play in these cases no part, is
obvious from the fact that the movements by which the
limb changes its position are passive ones, imprinted on it
by the experimenting physician. The writers who have
sought a rationale of the matter have consequently been
driven by way of exclusion to assume the articular surfaces
to be the seat of the perception in question, f
That the joint-surfaces are sensitive appears evident from
the fact that in inflammation they become the seat of excru-
ciating pains, and from the perception by everyone who
lifts weights or presses against resistance, that every in-
crease of the force opposing him betrays itself to his con-
sciousness principally by the starting-out of new feelings
or the increase of old ones, in or about the joints. If the
structure and mode of mutual application of two articular
surfaces be taken into account, it will appear that, granting
the surfaces to be sensitive, no more favorable mechanical
* See for example Duchenne, Electrisation localisee, pp. 727, 770, Ley*
den; Virchow's Archiv, Bd. xlvii. (1869).
t E.g., Eulenburg, Lehrb. d. Nervenkrankheiten (Berlin), 1878, i. 8.
192 P8TCH0L00Y.
conditions could be possible for the delicate calling of the
sensibility into play than are realized in the minutely grad-
uated rotations and firmly resisted variations of pressure
Involved in every act of extension or flexion. Nevertheless
it is a great pity that we have as yet no direct testimony,
no expressions from patients with healthy joints accident-
ally laid open, of the impressions they experience when the
cartilage is pressed or rubbed.
The first approach to direct evidence, so far as I know,
is contained in the paper of Lewinski,^ publiuhed in 1879.
This observer had a patient the inner half of whose leg
was anaesthetic. When this patient stood up, he had a
curious illusion about the position of his limb, which dis-
appeared the moment he lay down again : he thought him-
self knock-kneed. If, as Lewinski says, we assume the inner
half of the joint to share the insensibility of the corre-
sponding part of the skin, then he ought to feel, when the
joint-surfaces pressed against each other in the act of
standing, the outer half of the joint most strongly. But
this is the feeling he would also get whenever it was by any
chance sought to force his leg into a knock-kneed attitude.
Lewinski was led by this case to examine the feet of cer-
tain ataxic patients with imperfect sense of position. He
found in every instance that when the toes were flexed and
drawn upon at the same time (the joint-surfaces drawn
asunder) all sense of the amount of flexion disappeared.
On the contrary, when he pressed a toe m, whilst flexing it,
the patient's appreciation of the amount of flexion was
much improved, evidently because the artificial increase of
articular pressure made up for the pathological insensibil-
ity of the parts.
Since Lewinski' s paper an important experimental re-
search by A. Goldscheider t has appeared, which completely
establishes our point. This patient observer caused his
fingers, arms, and legs to be passively rotated upon their
various joints in a mechanical apparatus which registered
both the velocity of movement impressed and the amount
* 'Ueber den Kraftsinn,' Virchow's Archiv, Bd. lxxvii. 134.
f Archiv f . (Anat. u) Physiologic (1889), pp. 369, 540.
THE PERCEPTION OF SPACE. 193
of angular rotation. No active muscular contraction took
place. The minimal felt amounts of rotation were in all cases
surprisingly small, being much less than a single angular de-
gree in all the joints except those of the fingers. Such dis-
placements as these, the author says (p. 490), can hardly be
detected by the eye. The point of application of the force
which rotated the limb made no difference in the result.
Rotations round the hip-joint, for example, were as deli-
cately felt when the leg was hung by the heel as when it
was hung by the thigh whilst the movements were per-
formed. Anaesthesia of the skin produced by induction-cur-
rents also had no disturbing effect on the perception, nor
did the various degrees of pressure of the moving force
upon the skin affect it. It became, in fact, all the more
distinct in proportion as the concomitant pressure-feelings
were eliminated by artificial anaesthesia. When the joints
themselves, however, were made artificially anaesthetic the
perception of the movement grew obtuse and the angular
rotations had to be much increased before they were per-
ceptible. All these facts prove according to Herr Gold-
scheider, that the joint surfaces and these alone are the start-
ing point of the impressions by which the movements of our
members are immediately perceived.
Applying this result, which seems invulnerable, to the
case of the tracing finger-tip, we see that our perception of
the latter gives no countenance to the theory of the mus-
cular sense. We indubitably localize the finger-tip at the suc-
cessive points of its path by means of the sensations which toe
receive from our joints. But if this is so, it may be asked,
why do we feel the figure to be traced, not within the joint
itself, but in such an altogether different place ? And why
do we feel it so much larger than it really is ?
I will answer these questions by asking another : Why
do we move our joints at all ? Surely to gain something
more valuable than the insipid joint-feelings themselves.
And these more interesting feelings are in the main pro-
duced upon the skin of the moving part, or of some other
part over which it passes, or upon the eye. With move-
ments of the fingers we explore the configuration of all real
objects with which we have to deal, our own body as well as
IW P8YCH0L0OT.
foreign things. Nothing that interests us is located in the
joint ; everything that interests us either is some part of
our skin, or is something that we see as we handle it. The
cutaneously felt and the seen extents come thus to figure
as the important things for us to concern ourselves with
Every time the joint moves, even though we neither see,
nor feel cutaneously, the reminiscence of skin-events and
sights which formerly coincided with that extent of move-
ment, ideally awaken as the movement's import, and the
mind drops the present sign to attend to the import alone.
The joint-sensation itself, as such, does not disappear in
the process. A little attention easily detects it, with all
its fine peculiarities, hidden beneath its vaster suggestions ;
so that really the mind has two space-perceptions before
it, congruent in form but different in scale and place, either
of which exclusively it may notice, or both at once, — the
joint-space which it feels and the real space which it means.
The joint-spaces serve so admirably as signs because of
their capacity for parallel variation to all the peculiarities
of external motion. There is not a direction in the real
world nor a ratio of distance which cannot be matched by
some direction or extent of joint-rotation. Joint-feelings,
like all feelings, are roomy. Specific ones are contrasted
inter se as different directions are contrasted within the
same extent. If I extend my arm straight out at the
shoulder, the rotation of the shoulder- joint will give me one
feeling of movement ; if then I sweep the arm forward, the
same joint will give me another feeling of movement
Both these movements are felt to happen in space, and
differ in specific quality. Why shall not the specificness
of the quality just consist in the feeling of a peculiar direc-
tion ? * Why may not the several joint-feelings be so many
perceptions of movement in so many different directions ?
That we cannot explain why they should is no presumption
that they do not, for we never can explain why any sense-
organ should awaken the sensation it does.
* Direction iu its first intention,' of course; direction with which so
far we merely become acquainted, and about which we know nothing save
perhaps its difference from another direction a moment ago experienced Id
the same way !
THE PERCEPTION OF 8PA0E. 195
But if the joint-feelings are directions and extents,
standing in relation to each other, the task of association in
interpreting their import in eye- or skin-terms is a good deal
simplified. Let the movement be, of a certain joint, deiive
its absolute space-value from the cutaneous feeling it is
always capable of engendering ; then the longer movement
Jibed of the same joint will be judged to have a greater
apace-value, even though it may never have wholly merged
with a skin-experience. So of differences of direction : so
much joint- difference = so much skin-difference ; therefore,
more joint-difference = more skin-difference. In /aot, the
joint-feeling can exeellently serve as a map on a reduced scale^ of
a reality which the imagination can identify at its pleasure
with this or that sensible extension simultaneously known in
some other way.
When the joint-feeling in itself acquires an emotional
interest, — v/hich happens whenever the joint is inflamed
and painful, — the secondary suggestions fail to arise, and
the movement is felt where it is, and in its intrinsic scale oi
magnitude.*
The localization of the joint-feeling in a space simulta-
neously known otherwise (i.e. to eye or skin), is what is
commonly called the extradition or eccentric projection of the
feeling. In the preceding chapter I said a good deal on this
subject ; but we must now see a little more closely just what
happens in this instance of it. The content of the joint-
feeling, to begin with, is an object, and is in itself a place.
For it to be placed, say in the elbow, the elbow as seen or han-
dled must already have become another object for the mind,
* I have said hardly anything about associations with visual spaoe in
the foregoing account, because 1 wished to represent a process which the
blind and the seeing man might equally share. It is to be noticed that
the space suggested to the imagination when the joint moves, and pro-
jected to the distance of the finger-tip, is not represented as any specific
skin-tract. What the seeing man imagines is a visible path; what the blind
man imagines is rather a generic image, an abstraction from many skin-
spaces whose local signs have neutralized each other, and left nothing*but
their common vastness behind. We shall see as we go on that this generic
abstraction of space-magnitude from the various local peculiarities of feel-
ing which accompanied it when it was for the first time felt, occurs on a
considerable scale in the acquired perceptions of blind as well as of seeing
men.
196 P8T0H0L0QT.
and with its place as thus known, the place which the joint-
feeling fills must coalesce. That the latter should be felt
* in the elbow ' is therefore a * projection ' of it into the place
of another object as much as its being felt in the finger-tip
or at the end of a cane can be. But when we say ' projec-
tion ' we generally have in our mind the notion of a tliere as
contrasted with a here. What is the here when we say that the
joint-feeling is there ? The ' here ' seems to be the spot
which the mind has chosen for its own post of observation,
usually some place within the head, but sometimes within
the throat or breast — not a rigorously fixed spot, but a
region from any portion of which it may send forth its vari-
ous acts of attention. Extradition from either of these
regions is the common law under which we perceive the
whereabouts of the north star, of our own voice, of the con-
tact of our teeth with each other, of the tip of our finger,
of the point of our cane on the ground, or of a movement
in our elbow-joint.
But /or the distance between the * here ' and the * there ' to he
fdt, the entire intervening space must he itself an ohject of per-
teption. The consciousness of this intervening space is the
Bine qua non of the joint-feeling's projection to the farther
end of it. When it is filled by our own bodily tissues (as
where the projection only goes as far as the elbow or fin-
ger-tip) we are sensible of its extent alike by our eye, by
our exploring movements, and by the resident sensations
which fill its length. When it reaches beyond the limits
of our body, the resident sensations are lacking, but limbs
and hand and eye suffice to make it known. Let me, for
example, locate a feeling of motion coming from my elbow-
joint in the point of my cane a yard beyond my hand.
Either I see this yard as I flourish the cane, and the seen
end of it then absorbs my sensation just as my seen elbow
might absorb it, or I am blind and imagine the cane as an
object continuing my arm, either because I have explored
both arm and cane with the other hand, or because I have
pressed them both along my body and leg. If I project my
joint-feeling farther still, it is by a conception rather than a
distinct imagination of the space. I think: * farther,' * thrice
as far/ etc.; and thus get a symbolic image of a distant
THE PERCEPTION OF SPACE. 197
path at which I point.* But the * absorption * of the joint-
feeling by the distant spot, in whatever terms the latter
may be apprehended, is never anything but that coales-
cence into one ' thing ' already spoken of on page 184, of
whatever different sensible objects interest our attention at
once.
2. Fedings of Muscular Contraction,
Readers versed in psychological literature will have
missed, in our account thus far, the usual invocation of
*the muscular sense.' This word is used with extreme
vagueness to cover all resident sensations, whether of
motion or position, in our members, and even to designate
the supposed feeling of efferent discharge from the brain.
We shall later see good reason to deny the existence of the
latter feeling. We have accounted for the better part at least
of the resident feelings of motion in limbs by the sensibility
of the articular surfaces. The skin and ligaments also must
have feelings awakened as they are stretched or squeezed
in flexion or extension. And I am inclined to think that
the sensations of our contracting muscles themselves probably play
as small a part in building up our exact knowledge of space as
any cla^s of sensations which we possess. The muscles, indeed,
play an all-important part, but it is through the remote
effect of their contractions on other sensitive parts, not
through their own resident sensations being aroused. In
other words, muscular contraction is only indirectly instru-
mental, in giving us space-perceptions, by its effects on surfaxies.
In skin and retina it produces a motion of the stimulus
upon the surface ; in joints it produces a motion of the
surfaces upon each other — such motion being by far the
* The ideal enlargement of a system of sensations by the mind is noth-
ing exceptional. Vision is full of it ; and in the manual arts, where a
workman gets a tool larger than the one he is accustomed to and has sud-
denly to adapt all his movements to its scale, or where he has to execute
a familiar set of movements in an unnatural position of body; where a
piano-player meets an instrument with unusually broad or narrow keys;
where a man has to alter the size of his handwriting — we see how promptly
the mind multiplies once for all, as it were, the whole series of its opera-
tions by a constant factor, and has not to trouble itself after that with fui'
ther adjustment of the details.
198 PBTCHOLOOT.
most delicate manner of exciting the surfaces in question
One is tempted to doubt whether the muscular sensibilit;^
as such plays even a subordinate part as sign of these
more immediately geometrical perceptions which are so
uniformly associated with it as effects of the contraction
objectively viewed.
For this opinion many reasons can be assigned. First,
it seems a priori improbable that such organs as muscles
should give us feelings whose variations bear any exact
proportion to the spaces traversed when they contract.
As G. E. Miiller says,"^ their sensory nerves must be excited
either chemically or by mechanical compression whilst the
contractions last, and in neither case can the excitement be
proportionate to the position into which the limb is thrown.
The chemical state of the muscle depends on the previous
work more than on the actually present contraction ; and
the internal pressure of it depends on the resistance offered
more than on the shortening attained. The intrinsic mus-
cular sensations are likely tlierefore to he merely those of massive
strain or fatigue j and to carry no accurate discrimination with
them of lengths of path moved through.
Empirically we find this probability confirmed by many
facts. The judicious A. W. Volkman observes t that :
" Muscular feeling gives tolerably fine evidence as to the existence
of movement, but hardly any direct information about its extent or
direction. We are not aware that the contractions of a supinator
longus have a wider range than those of a supinator brevis ; and that
the fibres of a bipenniform muscle contract in opposite directions is a fact
of which the muscular feeling itself gives not the slightest intimation.
Muscle-feeling belongs to that class of general sensations which tell us
of our inner states, but not of outer relations ; it does not belong among
the space-perceiving senses."
E. H. Weber in his article Tastsinn called attention
to the fact that muscular movements as large and strong
as those of the diaphragm go on continually without our
perceiving them as motion.
G. H. Lewes makes the same remark. When we think
of our muscular sensations as movements in space, it is
* Pfltlger's Archiv, xiiV. 65.
f Untersuchungen im Gebiete der Optik, Leipzig (1863), p. 188
THE PERCEPTIOxi OF SPACE. 199
because we have ingrained with them in our imagination a
movement on a surface simultaneously felt.
" Thus whenever we breathe there is a contraction of the muscles
of the ribs and the diaphragm. Since we see the chest expanding, we
know it as a movement and can only think of it as such. But the dia-
phragm itself is not seen, and consequently by no one who is not physi-
ologically enlightened on the point is this diaphragm thought of in
movement. Nay, even when told by a physiologist that the diaphragm
moves at each breathing, every one who has not seen it moving down-
ward pictures it as an upward movement, because the chest moves
upward." *
A personal experience of my own seems strongly to cor-
roborate this view. For years I have been familiar, during
the act of gaping, with a large, round, smooth sensation in
the region of the throat, a sensation characteristic of gap-
ing and nothing else, but which, although I had often
wondered about it, never suggested to my mind the motion
of anything. The reader probably knows from his own
experience exactly what feeling I mean. It was not till one
of my students told me, that I learned its objective cause.
If we look into the mirror while gaping, we see that at the
moment we have this feeling the hanging palate rises by
the contraction of its intrinsic muscles. The contraction
of these muscles and the compression of the palatine mu-
cous membrane are what occasion the feeling ; and I was
at first astonished that, coming from so small an organ,
it could appear so voluminous. Now the curious point is
this — that no sooner had I learned by the eye its objective
space -significance, than I found myself enabled mentally to
feel it as a movement upwards of a body in the situation of
the uvula. When I now have it, my fancy injects it, so to
speak, with the image of the rising uvula ; and it absorbs
the image easily and naturally. In a word, a muscular
contraction gave me a sensation whereof I was unable dur-
ing forty years to interpret a motor meaning, of which two
glances of the eye made me permanently the master. To my
mind no further proof is needed of the fact that muscular
contraction, merely as such, need not be perceived directly
as so much motion through space.
* Problems of Life and Mind, prob. vi. chap. iv. § 45.
200 P8YCHOL007.
Take again the contractions of the muscles which make
the eyeball rotate. The feeling of these is supposed by
many writers to play the chief part in our perceptions of
extent. The space seen between two things meanSy accord-
ing to these authors, nothing but the amount of contraction
which is needed to carry i\iQ fovea from the first thing to the
second. But close the eyes and note the contractions in
themselves (even when coupled as they still are with the
delicate surface sensations of the eyeball rolling under the
lids), and we are surprised at finding how vague their space-
import appears. Shut the eyes and roll them, and you can
with no approach to accuracy tell the outer object which
shall first be seen when you open them again.* Moreover, it
our eye-muscle-contractions had much to do with giving us
our sense of seen extent, we ought to have a natural illusion
of which we find no trace. Since the feeling in the muscles
grows disproportionately intense as the eyeball is rolled
into an extreme eccentric position, all places on the extreme
margin of the field of view ought to appear farther from
the centre than they really are, for the fovea cannot get to
them without an amount of this feeling altogether in excess
of the amount of actual rotation, t When we turn to the
* Volkmann, op. cii. p. 189. Compare also what Hering says of the in-
ability in his own case to make after-images seem to move when he rolls
his closed eyes in their sockets ; and of the insignificance of his feelings of
convergence for the sense of distance (Beitrage zur Physiologic, 1861-2,
pp. 31, 141). Helmholtz also allows to the muscles of convergence a very
feeble share in producing our sense of the third dimension (Physiologische
Optik, 649-59).
f Compare Lipps, Psychologische Studien (1885), p. 18, and the other
arguments given on pp. 12 to 27. The most plausible reasons for contrac-
tions of the eyeball-muscles being admitted as original contributors to the
perception of extent, are those of Wundt, Physiologische Psychologic, ii.
96-100. They are drawn from certain constant errors in our estimate of
lines and angles ; which, however, are susceptible, all of them, of different
interpretations (see some of them further on). — Just as my MS. goes
to the printer, Herr Mtinsterberg's Beitrage zur experimentellen P^y-
chologie. Heft 2, comes into my hands with experiments on the measure-
ment of space recorded in it, which, in the author's view, prove the feeling
of muscular strain to be a principal factor in our vision of extent. As
Mtlnsterberg worked three hours a day for a year and a half at comparing
the length of lines, seen with his eyes in different positions ; and as he care-
fully averaged and ' percented ' 20,000 observations, his conclusion must be
listened to with great respect. Briefly it is this, that "our judgments of
THE PERCEPTION OF SPACE. 201
muscles of the body at large we find the same vagueness.
Goldscheider found that the minimal perceived rotation of
size depend on a comparison of the intensity of the feelings of movement
which arise in our eyeball-muscles as we glance over the distance, and
which fuse with the sensations of light " (p. 142). The facts upon which
the conclusion is based are certain constant errors which Miinsterberg
found according as the standard or given interval was to the right or the
left of the interval to be marked off as equal to it, or as it was above or
below it, or stood in some more complicated relation still. He admits that
he cannot explain all the errors in detail, and that we "stand before results
which seem surprising and not to be unravelled, because we cannot analyze
the elements which enter into the complex sensation which we receive."
But he has no doubt whatever of the general fact "that the movements of
the eyes and the sense of their position when fixed exert so decisive an
influence on our estimate of the spaces seen, that the errors cannot possi-
bly be explained by anything else than the movement-feelings and their
reproductions in the memory" (pp. 166, 167). It is presumptuous to doubt
a man's opinion when you haven't had his experience ; and yet there are a
number of points which make me feel like suspending judgment in regard
to Herr M.'s dictum. He found, for example, a constant tendency to under-
estimate intervals lying to the right, and to overestimate intervals lying
to the left. He ingeniously explains this as a result of the habit of read-
ing , which trains us to move our eyes easily along straight lines from left
to right, whereas in looking from right to left we move them in curved
lines across the page. As we measure intervals as straight lines, it costs
more muscular effort to measure from right to left than the other way,
and an interval lying to the left seems to us consequently longer than it
really is. Now I have been a reader for more years than Herr Miinster-
berg; and yet with me there is a strongly pronounced error the other way.
It is the rightward-lying interval which to me seems longer than it really
is. Moreover, Herr M. wears concave spectacles, and looked through them
with his head fixed. May it not be that some of the errors were due to dis-
tortion of the retinal image, as the eye looked no longer through the centre
but through the margin of the glass ? In short, with all the presumptions
which we have seen against muscular contraction being definitely felt as
length, I think that there may be explanations of Herr M.'s results which
have escaped even his sagacity ; and I call for a suspension of judgment
until they shall have been confirmed by other observers. I do not myself
doubt that our feeling of seen extent may be altered by concomitant mus-
cular feelings. In Chapter XVII (pp. 28-80) we saw many examples of
similar alterations, interferences with, or exaltations of, the sensory effect
of one nerve -process by another. I do not see why currents from the
muscles or eyelids, coming in at the same time with a retinal impression,
might not make the latter seem bigger, in the same way that a greater «w-
tensity in the retinal stimulation makes it seem bigger ; or in the way that
a greater extent of surface excited makes the color of the surface seem
stronger, or if it be a skin-surface, makes its heat seem greater ; or in th 
