able conditions a somewhat similar susceptil)ility to sug-
• M. La/.anis: Das Lflx-n d. Seelc (IH.')?), ii. p. IW. In tlio ordinary
bearing' of hpforh half the words we seem to hear are sniJplied out of
our own head. A language with which we are familiar is under-
stood even when spoken in low t/mes and far off. An nnfainiliar
language is unintelligil)ie under these conditions. 'Iht; ' idea.s ' for
Interpreting the sounds by not being ready-made in our minds, as they
are in our familiar mother Umgue, do not Htart up at uo faint a cue.
324 rSTCHOLOOT.
gestion may exist in certain persons who are not otherwise
entranced at all.
This suggestibility obtains in all the senses, although
high authorities have doubted this power of imagination
to falsify present impressions of sense. Everyone must be
able to give instances from the smell-sense. AVhen we
have paid the faithless plumber for pretending to mend
our drains, the intellect inhibits the nose from perceiving
the same unaltered odor, until perhaps 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 oppression disappears.
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 potato 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.
In the sense of hearing, similar mistakes abound. Every-
one must recall some experience in which sounds have
altered their 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 ir the garden," and was surprised at finding
the real source of the sound. I have had myself a striking
illusion of the sort. Sitting reading, late one night, I sud-
denly heard a most formidable noise proceeding from the
ujiper part of the house, whicli it seemed to fill. It ceased,
and in a moment renewed itself. I went into the hall to
listen, but it came no more. Resuming my seat in tlie
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
PERCEPTION. 325
hall, but it had already ceased once more. On returning
a seeoiul time to the room, I discovered tliat it was noth-
ing but tlie breatliing of a little Scotch terrier whicli lay
ask't']) on the floor, "i'lie notewortliy tiling is that as soon
as I recognized what it was, I was compelled to tliink it a
different sound, and could not then hear it as I had heard
it a moment before.
The sense of sight is pregnant Avith illusions of both the
types considered. No sense gives such fluctuating im-
pressions of the same object as sight does. AVith no sense
are we so apt to treat the sensations immediately given as
mere signs; with none is the invocation fi-om memory of a
thing, and the consequent perception of the latter, so
immediate. The 'thing' which avc perceive always resem-
bles, as we shall hereafter see, the object of some absent
sensation, usually another optical figure which in our mind
has come to be a standard bit of reality; and it is this in-
cessant reduction of our immediately given optical objects
to more standard and 'real' forms which has led some
authors into the mistake of thinking that our optical sen-
sations are originally and natively of no particular form
at all.
Of accidental and occasional illusions of sight numy
amusing examples might be given. Oul- will sullice. It
is a reminiscence of my own. I was lying in my berth in
a steamer listening to the sailors 'at their devotions with
tlie holystones' outside; when, on turning my eyes to the
wiiKhnv, I perceived with perfect distinctness that the
chief-engineer of the vessel iiad entered my state-room,
and was standing looking tlirougli tbe window at the men
at work u])on the guards. Surjirised at his intrusion, and
also at his intciitncss and immobility, I remaiiu'd watchijig
him aiul wondering how long be would stand thus. At
last I spoke; but getting no reply, sat \\\) 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-
326 P8YCH0L007.
looking man; and I saw him unmistakably; bnt after the
illusion had vanished I found it hard voluntarily to make
the cap and coat look like him at all.
' Apperception.' — In Germany since Herbart's time psy-
chology has always had a great deal to say about a process
called Apperception. The incoming ideas or sensations
are said to be ' apperceived ' by ' masses ' of ideas already
in the mind. It is plain that the process we have been
describing as perception is, at this rate, an apperceptive
process. So are all recognition, classing, and naming;
and passing beyond these simplest suggestions, all farther
thoughts about our percepts are apperceptive processes as
well. I have myself not used the word apperception, be-
cause it has carried very different meanings in the history
of philosophy, and ' psychic reaction,' ' interpretation,*
^conception/ 'assimilation,' 'elaboration,' or simply
* thought,' are perfect synonyms for its Herbartian mean-
ing, widely taken. It is, moreover, hardly worth while to
pretend to analyze the so-called apperceptive performances
beyond the first or perceptive stage, because their varia-
tions and degrees are literally innumerable. 'Appercep-
tion ' 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 ,-.her
words, his character, habits, memory, education, previous
experience, and momentary mood. We gain no insight
into what really occurs 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 'assimi-
lation ' the most fruitful one yet used.
The * apperceiving mass ' is treated by the Germans as
the active factor, the apperceived sensation as the passive
one; the sensation being usually modified by the ideas in
the mind. Out of the interaction of the two, cognition is
PERCEPTION. 327
prodiued. But as Steintlial remarks, the apperceiving
mass )6 itself often moditied by the sensation. To quote
liim: "Although the a jiri'ori moment commonly shows
itself to be the more powerful, apperception-processes can
perfectly well occur in which the new observation trans-
forms or enriches 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 ap-
perceiving 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 apperceived, i.e. brought into
connection with the system of our knowledge, transformed
the whole system. In principle, however, we must main-
tain that, although either factor is both active and passive,
the r priori factor is almost always the more active of the
two." *
Gonius and Old-fogyism. — This account of S^ceinthal's
brings out very clearly the difference between our psi/clio-
logicnl concepiions and jchat are called concei^ts 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 conceptions so adequate
and exact that we shall never need to change them. There
is an everlasting struggle in every mind between the ten-
dency to keep unchanged, and the tendency to renovate,
its ideas. Our education is a ceaseless compromise be-
tween the conservative and the progressive factors. Every
new experience must be disposed of under some old head.
The great point is to find the head w^hich has to bo least
altered to take it in. Certain Polynesian natives, seeing
horses for the first time, called them pigs, that being the
nearest head. My child of two j)layed for a week with the
first orange that was given him, calling it a * ball.' He
• Einleitunjj in dio Paychologie u. Sprax;hwiH«oaschatt (1881), p. 171.
328 P8YGH0L0OT,
called tlie 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 exjoeriences come.
Most of us grow more and more enslaved to the stock con-
ceptions with which we have once become familiar, and
less and less capable of assimilating impressions in any
but the old ways. Old-fogyism, in short, is the inevitable
terminus to which life sweeps us on. Objects which vio-
late 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
i]i, 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 scientific 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
* The great maxim in pedagogy is to knit every new piece of
knowledge on to a preexisting 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 is to explain the distance of the snn
from the earth, let him ask . . . ' If anyone there in the sun fired
rERCEPTION. 329
Darwin's voyage, \rondered at the small boats, but took
the big ship as a ' matter of course.' Only what we partly
know already inspires us with u desire to know more. The
more elaborate textile fabrics, the vaster works in metal,
to most of us are like the air, the water, and the ground,
absolute existences which awaken no ideas. It is a matter
of course that an engraving or a copper-plate inscription
should possess that degree of beauty. But if we are shown
ayjt'/i-drawing of equal perfection, our personal sympathy
with the difficulty of the task makes us immediately won-
der at the skill. The old lady admiring the Academician's
picture says to him: " And is it really all done hy hand?"
The Physiological Process in Perception. — Enough has
now been said to prove the general law of perception,
which is this: that u'hiht part of what we perceive comes
through our senses from the object before us, another part
(and it may be the larger part) always comes out of our
own mind.
At bottom this is but a case of the general fact that
our nerve-centres are organs for reacting on sense-im-
pressions, and that our hemispheres, in jiarticular, are given
us that records of our past private experience may coop-
erate in the reaction. Of course such a general state-
ment is vague. If we try to put an exact meaning into
it, what we find most natural to believe is that the brain
reacts by paths which the previous experiences have worn,
and which make us ^>r;reu*e the j^i'otnibJe tiling, i.e., the
thing by which on the previous occasions the reaction was
most frequently aroused. The reaction of the hemispheres
consists in the lighting up of a certain system of paths by
off a cannon straif,'lit at you, wliat should you do?' * (Jet out of tb«
way,' would he the answor. ' No need of that,' the teacher might
r»'iily. ' You may quii-tly gf) to slcpp in your room, and get up again,
you may wait till your confirmation-day, you may loarn a trade, and
f^row a-s old a.s I am, — tfu'ii only will tlur cuiinonhall In; getting near,
then you may jump to one side I See, w) great as that is the sun's
diBtADcel'" (VL Lange, Ueber Apperception, 1B79, p. 70.)
330 PSTCHOLOQT.
the current entering from the outer world. What corre>
sponds to this mentally is a certain special pulse of thought,
the thought, namely, of that most probable object. Far-
ther than this in the analysis we can hardly go.
Hallucinations. — Between normal perception and illu-
sion we have seen that there is no break, the 2)7'ocess being
identically the same in both. The last illusions we con-
sidered might fairly be called hallucinations. We must now
consider the false perceptions more commonly called by
that name. In ordinary parlance hallucination is held to
differ from illusion in that, whilst there is an object really
there in illusion, in liallucination there is no objective
stimulus at all. We shall presently see that this supposed
absence of objective stimulus in hallucination is a mistake,
and that hallucinations are often only extremes of the per-
ceptive process, in which the secondary cerebral reaction is
out of all normal proportion to the peripheral stimulus
which occasions the activity. Hallucinations usually ap-
pear 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 images projected
outwards by mistake. But where an hallucination is com-
plete, it is much more than a mental image. An hallu-
cination, subjectively considered, is a sensation, as good and
true a sensation as if there 2vere a real object there. The
object happens not to be there, that is all.
The milder degrees of hallucination have been designa-
ted as pseudo-hallucinations. Pseudo-hallucinations and
hallucinations have been sharply distinguished from each
other only within a few years. From ordinary images of
memory and fancy, pseudo-hallucinations differ in being
much more vivid, minute, detailed, steady, abrupt, and
spontaneous, in the sense that all feeling of our own activ-
ity in producing them is lacking. Dr. Kandmsky had a
patient who, after taking opium or haschisch, had abun*
dant pseudo-hallucinations and hallucinations. As he also
PERCEPTION. 331
had strong visualizing power and was an educated jiliysi-
cian, the three sorts of i)henoniena couUl be easily com-
pared. Although projected outwards (usually not farther
than the limit of distinctest vision, a foot or so), the pseudo-
hallucinations lacked 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-hallucina-
tions. They are described as ' inner ' voices, although their
character is entirely unlike the inner speech of the sub-
ject with himself. I know several 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 may at last grow into
vivid or completely exteriorized hallucinations. The lat-
ter are comparatively frequent occurrences in sporadic
form; and certain individuals are liable to have them
often. From the results of the * Census of Hallucinations,'
which was begun by p]dmund Gurne}^ 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 case from a healthy person will
give an idea of what these hallucinations are:
" When a girl of eighteen, I was one evening engaged in
a very painful discussion M'ith an elderly person. ^\\ dis-
tress was so great that I took up a thick ivory knitting-
needle that was lying on the mantelpiece of the parlor
and broke it into small pieces as I talked. In the midst
of the discussion I was very wishful to know the opinion
of a brother with whom I had an unusually close relation-
ship. I turned round and saw him sitting at the farther
side of a centre-taljle, with his arms folded (an unusual
position with him), but, to my dismay, I perceived from
the sarcaatic expression of his mouth that he was not in
sympathy with me, was not * taking my side,' as I should
332 PSTCHOLOOT.
then have expressed it. The surprise cooled me, and the
discussion was dropped.
"Some minutes after, having occasion to speak to my
brotlier, I turned towards him, but he was gone. I in-
quired 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 the house that evening. He is still alive and
well."
The hallucinations of fever-delirium are a mixture of
pseudo-hallucination, true hallucination, and illusion.
Those of opium, haschish, and belladonna resemble them
in this respect. The commonest hallucination of all is that
of hearing one's own name called aloud. Nearly one half
of the sporadic cases which I have collected are of this
sort.
Hallucination and Illusion. — Hallucinations are easily
produced by verbal suggestion in hypnotic subjects. Thus,
point to a dot on a sheet of paper, and call it ' General
Grant's photograph,' and your subject will see a photo-
graph 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 eye-
ball; 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 an inner image in the subject's mind. M. Binet has
shown that such a peripheral point de repere is used in an
enormous number, not only of hypnotic hallucinations, but
of hallucinations of the insane. These latter are often uni'
lateral; that is, the patient hears the voices always on one
PERCEPTION. 333
side of him, or sees the figure only when n certain one of his
eyes is o})on. In many of these cases it lias been distinctly
proved that a morbid irritation in the internal ear, or an
opacity in the humors of the eye, was the startinsf point of
the current which the patient's diseased acoustic or optical
centres clothed with their peculiar products in the way of
ideas. Ifdllucinatiinis pradiiri'il in f/n''< wnji are ' illusions';
and M. Bi net's f/ieari/, //idf all Iia/liicinatiutis must start in
the peripJieri/, niaij he called an attempt to reduce hallucina-
tion and illusion to one pliysiidngical type, the type, namely,
to which normal perception belongs. In every case, accord-
ing to M. Binet, whether of perception, of hallucination,
or of illusion, avc get the sensational vividness by means of
a current from the peri])heral nerves. It may be a mere
trace of a current. But that trace is enough to kindle the
maximal process of disintegration in the cells (cf. p. 31U),
and to give to the object perceived the character of exter-
nality. What the nature of the object shall be will depend
wholly on the particular system of paths in which the pro-
cess 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 parte;
and our oidy formula for the result is that the brain has
reacted on the impression in the resulting way.
M. Binet's theory accounts indeed for a multitude of
cases, lint certainly not for all. The prism does not always
douljlc the false appearance, nor does the latter always dis-
appear when the eyes are closed. For Binet, an abnor-
mally or ex'clusively active p;irt of the cortex give« the
nature of what shall appear, whilst a peripheral sense-
<^»rgan alone can give the intcnsiti/ suflicient to make it
aj)poar projectcfl into real space. But since this intensity
la after all l)ut a matter of degree, one does not see why,
under rare conditions, the degree in qncsfion init/Iit not
be attained by inner causes exclusively. In (bat case we
should have certain hallucinations centrally initiated, as
well as the peripherally initiatcMl hallucinations which ur©
334 PSYCHOLOGY.
the only sort that M. Binet's theory allows. It seems prob-
able on the ivhole, therefore, that centrally initiated hallu-
cinations can exist. How often they do exist is another
question. The existence of hallucinations which affect
more than one sense is an argument for central initiation.
For, grant that the thing seen may 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 a quite frequent 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 coinciding with
real events, such as accidents, deaths, etc., of the persons
seen, is an additional complication of the phenomenon.
The first really scientific study of hallucination in all its
possible bearings, on the basis of a large mass of empirical
material, was begun by Mr. Edmund Gurney and is con-
tinued by other members of the Society for Psychical Ee-
search; 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 Avide compar-
ative study can give really instructive results.*
* The writer of the present work is Agent of the Census for
America, and will thankfully receive accounts of cases of hallucina-
tion of vision, hearing, etc., of which the reader may have knowledge.
CHAPTER XXI.
THE PERCEPTION OF SPACE.
As adult thinkers we liave a definite and apparently
instantaneous knowledge of the sizes, shapes, and dis-
tances of the things amongst which we live and move;
and we have moreover a 2)ractically definite notion of the
whole great infinite continuum of real space in which the
world swings and in which all these things are located.
Nevertheless it seems ohvious that the baby's world is
vague and confused in all these respects. How does our
definite knowledge of space grow up ? This is one of the
quarrelsome problems in psychology. This chapter must
be so brief that there will be no room for the polemic and
historic aspects of the subject, and I will state simply and
dogmatically the conclusions which seem most plausible to
me.
The quality of voluminousness exists in all sensations,
just as intensity does. AVe call the reverberations of a
thunder-storm 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