_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 séances' 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 expectancy have so filled his mind with

premonitory images that it is no wonder he perceives what is suggested.

These fraudulent 'séances' would furnish most precious documents 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 interpreted

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,

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; whereupon 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 of _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 feeling 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 exposed to confound objects of touch with

one another."[102]

High authorities have doubted this power of imagination to falsify

present impressions of sense.[103] Yet it unquestionably exists.

Within the past fortnight I have been annoyed by a smell, faint but

unpleasant, in my library. My annoyance 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

impression during part of this time was one of uncertainty whether

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 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.

An extreme instance is given in the following extract:

"A patient called at my office 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, difficulty in breathing, and other evidences of bodily

and mental distress. I succeeded, after some difficulty 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 office 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."[104]

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.

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 discovered? "Bless me, how heavy it is!" said the

man; 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. 71). 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 surprised 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 itself. 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 noteworthy 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 Delbœuf and Reid, this was probably also the

case, though it is not so stated. Reid 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 discovered

that the sound was in my own breast." (Inquiry, chap. iv. § 1.)

Delbœuf'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

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."[105]

The sense of sight, as we have seen in studying Space, is pregnant with

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 consequent

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 form at all.[106]

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 outside; when, on turning my eyes to the window, I perceived

with perfect distinctness that the chief-engineer of the vessel 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 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 I 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

circumstances 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 awake 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 commonly 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 grapple 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 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 window. If

I had given way to the first terror of the situation and covered

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,

exaggerated the vividness of my feelings."

THE PHYSIOLOGICAL PROCESS IN PERCEPTION.

Enough, has now been said to prove the general law of perception, which

is this, that _whilst 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_ (in Lazarus'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

describing the process goes much more into detail. The sensation,

they say, awakens 'images' of other sensations associated with it in

the past. These images 'fuse,' or are 'combined' by the Ego with the

present sensation into a new product, the percept, etc., etc. Something

so indistinguishable from this in practical outcome is what really

occurs, that one may seem fastidious in objecting to such a statement,

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 thing, i.e., the thing by which on previous

occasions the reaction was most frequently 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 sensation, 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 discharge, the excitement will linger there longer ere it diffuses

itself elsewhere, and our consciousness of the sort of object 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 current _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 consciousness 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 consciousness for those of the thing immediately there;

or, more briefly, _just in proportion as an experience is probable will

it tend to be 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 down by Reid and Helmholtz

that true sensations 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 will 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 as if the

movement had actually taken place._ This seems habitually to be the

case in anæsthesia of the moving parts. Close the patient's eyes,

hold his anæsthetic 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 anæsthetic cases

seem to mention this illusion. Sternberg who wrote on the subject in

1885,[107] 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 hallucinatory intensity. Sternberg gives the following

experiment, which I find succeeds with at least half of those who

try it: Rest 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. He quotes from Exner a similar experiment with the

jaws: Put some hard rubber or other unindentable obstacle between

your back teeth and bite hard: you think you feel the jaw move and the

front teeth approach each other, though in the nature of things no

movement can occur.[108]--The visual suggestion of the path traversed

by the finger-tip as the _locus_ of the movement-feeling in the

joint, which we discussed on page 41, is another example of this

semi-hallucinatory 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.[109] But the curious thing is that many

of these patients can _will the foot to move_, and when they have done

so, distinctly _feel the movement to occur_. They can, to use their own

language, 'work' or 'wiggle' their lost toes.[110]

Now in all these various cases we are dealing with data which in normal

life are inseparably joined. Of all possible experiences, it is hard

to imagine any pair more uniformly 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 effect there is

a contradictory sensation. We discern a resistance or the unchanged

position of the limb. But neither in anæsthesia nor in amputation can

there be any contradictory sensation in the foot to correct us; so

imagination has all the force of fact.

'APPERCEPTION.'

In Germany since Herbart's time Psychology has always had a great

deal to say about a process called _Apperception_.[111] 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 because it has carried very different meanings in the

history of philosophy,[112] 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 performances beyond the first or perceptive stage, because

their variations 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 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

'assimilation' the most fruitful one yet used.[113]

Professor H. Steinthal has analyzed apperceptive processes with a sort

of detail which is simply burdensome.[114] 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 thereupon 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 soldier'; 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

and 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,[115] and that is whatever is most newly related to his

pursuit in life. Every question is a hole-drilling experiment, and the

answer 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

has 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 and of children, consists of masses or circles of

knowledge of which each lies within some larger circle, alongside

of others similarly included, 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 supervening factor is given,

_a posteriori_, passive.... We may then define Apperception as the

movement of two masses of consciousness (Vorstellungsmassen) against

each other so as to produce a cognition.

"The _a priori_ factor we called active, the _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 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 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 apperceived, 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."[116]

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 conceptions 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 ceaseless compromise between

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 which has to be 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 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 experiences 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

impressions 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.[117] The Fuegians,

in Darwin's voyage, 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 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 a _pen_-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 _by

hand_?"

IS PERCEPTION UNCONSCIOUS INFERENCE?

A widely-spread opinion (which has been held by such men as

Schopenhauer, Spencer, Hartmann, Wundt, Helmholtz, and lately

interestingly pleaded for by M. Binet)[118] will have it that

_perception should be called a sort of reasoning operation, more or

less unconsciously and automatically performed_. The question seems at

first a verbal one, depending 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 reasoning. 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 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.[119]

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 contiguity, no

_naming_ of _those_ as M, but only a suggestion of unnamed similar

images, a recall of analogous past sensations with which the characters

that make up A were habitually 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 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 association 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 Perception. _Sir Wm.

Hamilton thought that he had discovered a 'great law'_ which had been

wholly overlooked by psychologists, and which, 'simple and universal,'

is this: "Knowledge and Feeling,--Perception and Sensation, though

always 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 consciousness, 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.[120] Apart

from pleasure 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 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.[121]

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.[122] In ordinary parlance hallucination is held to differ from

illusion in that, whilst there is an object really there in illusion,

_in hallucination 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 perception process, in which the secondary cerebral

reaction is out of all normal proportion to the peripheral stimulus

which occasions the activity. Hallucinations 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 hallucination

is complete, it is much more than a mental image. _An hallucination

is a strictly sensational form of consciousness, 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 designated as

_pseudo-hallucinations_. Pseudo-hallucinations and hallucinations have

been sharply distinguished from each other only within a few years.

Dr. Kandinsky 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 subjective 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 experience_ 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 Russia, he reflected a moment

what allegiance would be better, and resolved to become an English

subject. 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,' whereupon the patient recollected that the lion was the

national emblem of England. The lion appeared to L. very distinct

and vivid, but he nevertheless remained conscious, as he afterwards

expressed it, that he saw the animal, not with his bodily but with

his mental eyes. (After his recovery 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 objective reality he

was at the time quite convinced."[123]

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 activity

in producing them is lacking. Dr. Kandinsky had a patient who, after

taking opium or haschisch, had abundant pseudo-hallucinations and

hallucinations. 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

_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-hallucinations. They are described as '_inner_' voices, although

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

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 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.[124] 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

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 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

perceived from the sarcastic expression of his mouth that he was not

in sympathy with me, was not 'taking my side,' as I should then have

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 the 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

turning 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 felt 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 following 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 formulæ. 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 formulæ, and I had

been working on trigonometry the entire evening. About eleven o'clock,

as I sat there buried in sines, cosines, tangents, cotangents,

secants, and cosecants, I felt very distinctly upon my left shoulder

a touch, and a slight shake, as if somebody had tried to attract my

attention 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

information 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 I proceeded, however, the

impression 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,' '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."[125]

The hallucination sometimes carries a change of the general

consciousness with it, so as to appear more like a sudden lapse into a

dream. The following case was given me by a man of 43, who had 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

experienced. 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 dreaming 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 _cleanness_. I 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 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.

Directly 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

changing 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 common objects of life and many unreal monstrosities,

which it is absolutely 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 considerable

will-power managed to time the heart-beats, 135 to the minute.

"I could feel each pulsation through my whole system, and a curious

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 whirling 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 thereafter.)

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. I could

distinctly feel myself a fox, could see my long ears and bushy 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 example,

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

whirling 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

reappeared 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 monstrosity

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 NEURAL PROCESS IN HALLUCINATION.

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 process 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

degree with that which real external objects are usually needed to

induce. The particular process which currents from the sense-organs

arouse would seem under normal circumstances to be arousable in no

other way. On p. 72 ff. above, we saw that the centres aroused by

incoming peripheral currents are probably identical with the centres

used in mere imagination; and that the vividness of the sensational

kind of consciousness is probably correlated with a discrete degree of

_intensity_ in the process therein aroused. Referring the reader back

to that passage 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 conception, and whilst making it still more precise,

use it for explaining 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 vanquish the supra-ideational resistance (so to call it) of the

cells, and cause the peculiarly intense sort of disintegration with

which the sensational quality is linked. _If, however, the leakage

forward were to stop,_ the tension inside certain 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 associated cells. Now let two other vessels have

the function 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 consequently 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 _ideational_ activity is aroused. The other vessel,

however, stands for the peripheral sense-organs, and supplies 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 A B C D E, 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 _the substantive strength

of a state of consciousness bears 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 associative

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' hallucinations[126] are the regular concomitant of the

process of falling asleep. Trains of faces, landscapes, etc., pass

before the mental eye, first as fancies, then as pseudo-hallucinations,

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 of 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 sensations 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.[127] And yet it certainly fails to explain the extraordinary

vivacity and completeness of so many of our dream-fantasms. The process

of 'imagining' must (in these cases at least[128]) 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 as

far as that point is concerned.

Dr. Hughlings Jackson's explanation of the epileptic seizure is

acknowledged to be masterly. It involves 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 instinctive)

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.[129]

Similarly the _subsultus tendinorum_ or jerking of the muscles which so

often startles us when we are on the point of falling asleep, may be

interpreted as due to the rise (in certain lower motor centres) of the

ordinary 'tonic' tension to the explosion-point, when the inhibition

commonly exerted 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 thrown out of

gear, any activity which may exist in the first centre tends to

increase in intensity until finally the point may be reached at which

the last inward resistance is overcome, and the full sensational

process explodes._[130] Thus it will happen that causes of an amount

of activity in brain-cells which would ordinarily result in a weak

consciousness may produce 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. Instantly he dreamed that some one had

struck him a blow. Examples can be quoted _ad libitum_, but these are

enough.[131]

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 intensity therein._

* * * * *

In the hallucinations artificially produced in hypnotic subjects, some

degree of peripheral excitement seems usually to be required. The brain

is asleep as far as its own spontaneous thinking goes, and the words

of the 'magnetizer' 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 perception 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,[132] the dot is the outward _point de repère_ which is

needed to give objectivity to your suggestion, and without which the

latter will only produce a _conception_ in the subject's mind.[133]

M. Binet has shown that such a peripheral _point de repère_ 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.

Binet's 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 perception

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 current. 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 system 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 abnormal way.

_M. Binet's theory accounts indeed for a multitude of cases, but

certainly not for all._ The prism does not always double the false

appearance,[134] nor does the latter always disappear when the eyes

are closed. Dr. Hack Tuke[135] gives several examples in sane people

of well-exteriorized hallucinations which did not respond to Binet's

tests; and Mr. Edmund Gurney[136] gives a number of reasons why

intensity in a cortical process may be expected to result from local

pathological 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 peripheral 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 hallucinations 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 by far the most 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 continued by other

members of the Society for Psychical 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.[137]

_The part played by the peripheral sense-organ_ in hallucination is

just as obscure as we found it in the case of imagination. 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 involved 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 Féré, 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 perception-time, some

choice-time, some discrimination-time. The results have been already

given in Chapter XIII (vol. I, p. 523 ff.), to which the reader is

consequently referred.

Dr. Romanes gives an interesting variation of these time-measurements.

He found[138]

"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 persons 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 accidental differences arising from greater or less

facility acquired by special practice.

"My experiments consisted in marking a brief printed paragraph in a

book which had never been read by any of the persons to whom it was

to be presented. The paragraph, which contained simple statements 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 paragraph 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 experiment 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 better account of the portions of the paragraph which have been

compassed by the slow readers than the latter are able to give; and

the most 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

general results of intellectual work; for I have tried the experiment

with several highly distinguished men in science and literature, most

of whom I found to be slow readers."[139]

* * * * *

[83] The word Perception, however, has been variously used. For

historical notices, see Hamilton's Lectures on Metaphysics, ii. 96. For

Hamilton perception is 'the consciousness of external objects' (_ib._

28). Spencer defines it oddly enough as "a discerning of the relation

or relations between _states of consciousness_ partly presentative and

partly representative; which states of consciousness must be themselves

known to the extent involved in the knowledge of their relations"

(Psychol., § 355).

[84] Analysis, i. 97.

[85] Theory of Vision, 51.

[86] The educative process is particularly obvious in the case of the

ear, for all sudden sounds seem alarming to babies. The familiar noises

of house and street keep them in constant trepidation until such time

as they have either learned the objects which emit them, or have become

blunted to them by frequent experience of their innocuity.

[87] Outlines, p. 153.

[88] Cf. Helmholtz, Optik, pp. 433, 723, 728, 772; and Spencer,

Psychology, vol. ii. p. 249, note.

[89] The more or less geometrically regular phantasms which are

produced by pressure on the eyeballs, congestion of the head,

inhalation of anæsthetics, etc., might again be cited to prove that

faint and vague excitements 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 developing 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 Müller'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 Sinnestäuschungen, 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

summits we see like a crown the glaciers of Titlis, Uri-Rothsdock, etc.

I was 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 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. I thought at once that I 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 appear 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 determined color.--I

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

examination had been too powerful. All grew suddenly pale, and the

subjective phenomenon, which might have lasted some minutes longer, had

disappeared.--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 the 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 complementary color; and

my reminiscence, incorporating itself with this subjective sensation,

became the corpse-like phantom I have described."

[90] Cf. Th. Reid's Intellectual Powers, essay ii. 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 cases.

[91] 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 us 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 corresponding points _a_ and

_b_ simultaneously _pressed_, we do get something like the illusion of

singleness--that is, we get a very doubtful doubleness.

[92] Purkinje, Mach, and Breuer are the authors to whom we mainly owe

the explanation of the feeling of vertigo. I have found (American

Journal 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.

[93] 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 in Chapter XX.

[94] We never, so far as I know, get the converse illusion at a

railroad station and believe the other train to move when it is still.

[95] Helmholtz: Physiol. Optik, 365.

[96] Cf. Berkeley's Theory of Vision, §§ 67-79; Helmholtz:

Physiologische Optik, pp. 630-1; Lechalas in Revue Philosophique, xxvi.

49.

[97] Physiol. Optik, p. 602.

[98] 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 contraction of the external _recti_. But this

is a sign of the object's recession, etc.

[99] American Journal of Psychology, i. 101 ff.

[100] Romanes, Mental Evolution in Animals, p. 324.

[101] 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

understood, 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 interpreting 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.

[102] G. H. Meyer, Untersuchungen, etc., pp. 242-8.

[103] Helmholtz, P. O. 438. The question will soon come before us again

in the chapter on the Perception of Space.

[104] C. F. Taylor, Sensation and Pain, p. 37 (N. Y., 1882).

[105] Examen Critique de la Loi Psychophysique (1883), p. 61.

[106] Compare A. W Volkmann's essay 'Ueber Ursprüngliches und

Erworbenes in den Raumanschauungen,' on p. 139 of his Untersuchungen

im Gebiete der Optik; and Chapter xiii of Hering's contribution to

Hermann's Handbuch der Physiologie, vol. iii.

[107] 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 consciousness. Out of 140 persons whom I found 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 hallucination 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

altogether, contain. Many patients say they can hardly tell whether

they feel or fancy the limb."

[108] Pflüger's Archiv, xxxvii. 1.

[109] Not all patients have this additional illusion.

[110] I ought to say that in _almost_ all cases the volition is

followed by actual contraction of muscles in the _stump_.

[111] Cf. Herbart, Psychol. als. Wissenschaft, § 125.

[112] 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.

[113] Problems, vol. i. p. 118 ff.

[114] See his Einleitung in die Psychologie u. Sprachwissenschaft

(1881) p. 166 ff.

[115] One of my colleagues, asking himself the question after reading

the anecdote, tells me that he replied 'Harvard College,' the faculty

of that body having voted, a few days previously, to keep back the

degrees of members of the graduating class who might be disorderly on

class-day night. W. J.

[116] _Op. cit._ pp. 166-171.

[117] The great maxim in pedagogy is to knit every new piece of

knowledge 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 is to explain the distance of the sun from

the earth, let him ask.... 'If anyone 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

am,--_then_ only will the cannon-ball be getting 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.)

[118] 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, Beiträge, pp. 422 ff.; Vorlesungen, iv,

xiii. H. Helmholtz, Physiol. Optik, pp. 430, 447. A. Binet, Psychol.

du Raisonnement, chaps. iii, v. Wundt and Helmholtz have more recently

'recanted.' See above, vol i. p. 169 note.

[119] 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 draw false conclusions from undistributed middle terms.

[120] See Spencer, Psychol., ii. p. 250, note, for a physiological

hypothesis to account for this fact.

[121] 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 peculiarities. 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 position."

[122] Illusions and hallucinations must both be distinguished from

_delusions_. A delusion is a false opinion about a matter of fact,

which need not necessarily 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 in church; having no stomach;

being pregnant; having no inside;

having a bone in the throat; having neither stomach nor brains;

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 starved; the legs being made of glass;

that the flesh is boiling; having horns on the head;

that the head is severed from being chloroformed;

the 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 body;

having committed an rape being practised on her;

unpardonable sin; having a venereal disease;

unseen agencies working; being a fish;

her own identity; being dead;

being on fire; having committed suicide of the soul.

[123] V. Kandinsky: Kritische u. Klinische Betrachtungen im Gebiete d.

Sinnestäuschungen (1886), p. 42.

[124] See Proceedings of Soc. for Psych. Research, Dec. 1889, pp. 7,

183. The International Congress for Experimental Psychology has now

charge of the Census, and the present writer is its agent for America.

[125] This case is of the class which Mr. Myers terms 'veridical.' In a

subsequent letter the writer informs me that his vision occurred some

five hours _before_ the child was born.

[126] Le Sommeil et les Rêves (1865), chaps. iii, iv.

[127] 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.

[128] Not, of course, in all cases, because the cells remaining active

are themselves on the way to be overpowered by the general (unknown)

condition to which sleep is due.

[129] 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, i. 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 handkerchief, 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 touching me, I feel the figure decay, lose color, and

evaporate: what had appeared 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 evaporate; 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 Müller's Physiology, Baly's tr., p. 945.

[130] 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 narrow, 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 circumstances, 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.

[131] M. A. Maury gives a number: _op. cit._ pp. 126-8.

[132] M. Binet'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 Féré's work on 'Animal

Magnetism' in the International 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.

[133] It is a difficult 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 other hand, 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 sometimes they point to the imaginary

flower.

[134] Only the other day, to three hypnotized girls, I failed to

double a hallucination with a prism. Of course it may not have been a

fully-developed hallucination.

[135] Brain, xi. 441.

[136] Mind, x. 161, 316; and Phantasms of the Living (1886), i. 470-488.

[137] In Mr. Gurney's work, just cited, a very large number of

veridical cases are critically discussed.

[138] Mental Evolution in Animals, p. 186.

[139] _Literature._ The best treatment of perception with which I am

acquainted is that in Mr. James Sully's book on 'Illusions' in the

International Scientific Series. On hallucinations the literature is

large. Gurney, Kandinsky (as already cited), and some articles by

Kraepelin in the Vierteljahrschrift für Wissenschaftliche Philosophie,

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.

CHAPTER XX.

THE PERCEPTION OF SPACE.[140]

THE FEELING OF CRUDE EXTENSITY.

_In the sensations of hearing, touch, 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

extensive than the heavy soreness of a boil or the vast discomfort

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 extension 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 the other. The epithet _sharp_ given to the acid class would seem

to show that to the popular mind 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. Repletion and emptiness, 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 attention

can subdivide this vastness and perceive it to be composed of lesser

portions simultaneously coexisting alongside of each other is without

a parallel elsewhere.[141] The ear gives a greater vastness than the

skin, but is considerably less able to subdivide it.[142]

* * * * *

_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,[143] on this view, becomes an element in each

sensation just as intensity is. The latter every one will admit to

be a distinguishable though not separable ingredient of the sensible

quality. In like manner extensity, being an entirely peculiar 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

element_.

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."[144] Loud sounds have a certain 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 starting 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."[145] A luminous fog, a band of sunshine, affect us in the same

way. As Hering urges:

"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 darkness, 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 sensation 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 completely 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 experience 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."[146]

_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

direction, or differently localized tension (_Spannung_). We feel

a strain forward 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 the attention vibrates rapidly between eye

and ear. This feeling localizes 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 feeling 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."[147]

It appears probable that the feelings which Fechner describes are in

part constituted by imaginary semi-circular canal sensations.[148]

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.[149]

In the skin itself there is a vague form of projection into the third

dimension to which Hering has called attention.

"Heat is not felt only against the cutaneous surface, but when

communicated 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 explored 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 butterfly. 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 introducing 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 we 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.

The tympanic membrane is furthermore able to render sensible

differences in the pressure of the external atmosphere, 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 departure.

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 _quâ_ 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

immediately 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.[150]

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 feelings 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 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 equidistant

(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 horizontally 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-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

appearance 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.

[Illustration: FIG. 51 (after Weber).]

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 distance between its extremities

will seem shorter than that between two compass-tips touching the same

terminal points.[151]

[Illustration: FIG. 52 (after Weber).]

In the eye, intensity of nerve-stimulation seems to increase 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.[152] The inverse effect

seems produced by certain drugs and anæsthetics. Morphine, atropine,

daturine, and cold blunt the sensibility of the skin, so that distances

upon it seem less. Haschish produces strange perversions of the general

sensibility. Under its influence one's body may seem either enormously

enlarged or strangely contracted. Sometimes 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 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

darkened over and the roaring in his ears began. He also mentions 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

beginning of chloroformization. In various cerebral diseases we find

analogous disturbances.