[455] Philosophische Studien, v, 514-5.

[456] Cf. G. E. Müller: Zur Grundlegung der Psychophysik, §§ 68-70.

[457] Philosophische Studien, v, 287 ff.

[458] American J. of Psychology, iii, 44-7.

[459] Cf. Stumpf, Tonpsychologie, pp. 397-9. "One sensation cannot be

a multiple of another. If it could, we ought to be able to subtract

the one from the other, and to feel the remainder by itself. Every

sensation presents itself as an indivisible unit." Professor von Kries,

in the Viertejahrschrift für wiss. Philosophie, vi, 257 ff., shows very

clearly the absurdity of supposing that our stronger sensations contain

our weaker ones as parts. They differ as qualitative units. Compare

also J. Tannery in Delbœuf's Éléments de Psychophysique (1883), p. 134

ff.; J. Ward in Mind, i, 464: Lotze, Metaphysik, § 258.

[460] F Brentano, Psychologie, i, 9, 88 ff.--Merkel thinks that his

results with the method of equal-appearing intervals show that we

compare considerable intervals with each other by a different law from

that by which we notice barely perceptible intervals. The stimuli form

an arithmetical series (a pretty wild one according to his figures)

in the former case, a geometrical one in the latter--at least so I

understand this valiant experimenter but somewhat obscure if acute

writer.

[461] This is the formula which Merkel thinks he has verified (if I

understand him aright) by his experiments by method 4.

[462] Elsas: Ueber die Psychophysik (1856), p. 41. When the pans

of a balance are already loaded, but in equilibrium, it takes a

proportionally larger weight added to one of them to incline the beam.

CHAPTER XIV.[463]

ASSOCIATION.

After discrimination, association! Already in the last chapter I

have had to invoke, in order to explain the improvement of certain

discriminations by practice, the 'association' of the objects to be

distinguished, with other more widely differing ones. It is obvious

that the advance of our knowledge _must_ consist of both operations;

for objects at first appearing as wholes are analyzed into parts,

and objects appearing separately are brought together and appear as

new compound wholes to the mind. Analysis and synthesis are thus

the incessantly alternating mental activities, a stroke of the one

preparing the way for a stroke of the other, much as, in walking,

a man's two legs are alternately brought into use, both being

indispensable for any orderly advance.

The manner in which trains of imagery and consideration follow each

other through our thinking, the restless flight of one idea before

the next, the transitions our minds make between things wide as

the poles asunder, transitions which at first sight startle us by

their abruptness, but which, when scrutinized closely, often reveal

intermediating links of perfect naturalness and propriety--all this

magical, imponderable streaming has from time immemorial excited

the admiration of all whose attention happened to be caught by its

omnipresent mystery. And it has furthermore challenged the race of

philosophers to banish something of the mystery by formulating the

process in simpler terms. The problem which the philosophers have set

themselves is that of ascertaining _principles of connection_ between

the thoughts which thus appear to sprout one out of the other, whereby

their peculiar succession or coexistence may be explained.

But immediately an ambiguity arises: which sort of connection is meant?

connection _thought-of_, or connection _between thoughts_? These are

two entirely different things, and only in the case of one of them

is there any hope of finding 'principles.' The jungle of connections

_thought of_ can never be formulated simply. Every conceivable

connection may be thought of--of coexistence, succession, resemblance,

contrast, contradiction, cause and effect, means and end, genus and

species, part and whole, substance and property, early and late, large

and small, landlord and tenant, master and servant,--Heaven knows what,

for the list is literally inexhaustible. The only simplification which

could possibly be aimed at would be the reduction of the relations to

a smaller number of types, like those which such authors as Kant and

Renouvier call the 'categories' of the understanding.[464] According as

we followed one category or another we should sweep, with our thought,

through the world in this way or in that. And all the categories would

be logical, would be relations of reason. They would fuse the items

into a continuum. Were _this_ the sort of connection sought between one

moment of our thinking and another, our chapter might end here. For the

only summary description of these infinite possibilities of transition,

is that they are all _acts of reason_, and that the mind proceeds from

one object to another by some rational path of connection. The trueness

of this formula is only equalled by its sterility, for psychological

purposes. Practically it amounts to simply referring the inquirer to

the relations between facts or things, and to telling him that his

thinking follows them.

But as a matter of fact, his thinking only sometimes follows them,

and these so-called 'transitions of reason' are far from being all

alike reasonable. If pure thought runs all our trains, why should she

run some so fast and some so slow, some through dull flats and some

through gorgeous scenery, some to mountain-heights and jewelled mines,

others through dismal swamps and darkness?--and run some off the track

altogether, and into the wilderness of lunacy? Why do we spend years

straining after a certain scientific or practical problem, but all in

vain--thought refusing to evoke the solution we desire? And why, some

day, walking in the street with our attention miles away from that

quest, does the answer saunter into our minds as carelessly as if it

had never been called for--suggested, possibly, by the flowers on the

bonnet of the lady in front of us, or possibly by nothing that we can

discover? If reason can give us relief then, why did she not do so

earlier?

The truth must be admitted that thought works under conditions imposed

_ab extra_. The great law of habit itself--that twenty experiences

make us recall a thing better than one, that long indulgence in error

makes right thinking almost impossible--seems to have no essential

foundation in reason. The business of thought is with truth--the number

of experiences ought to have nothing to do with her hold of it; and she

ought by right to be able to hug it all the closer, after years wasted

out of its presence. The contrary arrangements seem quite fantastic

and arbitrary, but nevertheless are part of the very bone and marrow

of our minds. Reason is only one out of a thousand possibilities in

the thinking of each of us. Who can count all the silly fancies, the

grotesque suppositions, the utterly irrelevant reflections he makes in

the course of a day? Who can swear that his prejudices and irrational

beliefs constitute a less bulky part of his mental furniture than

his clarified opinions? It is true that a presiding arbiter seems

to sit aloft in the mind, and emphasize the better suggestions into

permanence, while it ends by dropping out and leaving unrecorded the

confusion. But this is all the difference. The _mode of genesis_ of

the worthy and the worthless seems the same. The laws of our actual

thinking, of the _cogitatum_, must account alike for the bad and the

good materials on which the arbiter has to decide, for wisdom and for

folly. The laws of the arbiter, of the _cogitandum_, of what we _ought_

to think, are to the former as the laws of ethics are to those of

history. Who but an Hegelian historian ever pretended that reason in

action was _per se_ a sufficient explanation of the political changes

in Europe?

* * * * *

_There are, then, mechanical conditions on which thought depends,

and which,_ to say the least, _determine the order in which is

presented the content or material for her comparisons, selections, and

decisions._ It is a suggestive fact that Locke, and many more recent

Continental psychologists, have found themselves obliged to invoke a

mechanical process to account for the _aberrations_ of thought, the

obstructive preprocessions, the frustrations of reason. This they found

in the law of habit, or what we now call Association by Contiguity.

But it never occurred to these writers that a process which could

go the length of actually producing some ideas and sequences in the

mind might safely be trusted to produce others too; and that those

habitual associations which further thought may also come from the

same mechanical source as those which hinder it. Hartley accordingly

suggested habit as a sufficient explanation of all connections of our

thoughts, and in so doing planted himself squarely upon the properly

psychological aspect of the problem of connection, and sought to treat

both rational and irrational connections from a single point of view.

The problem which he essayed, however lamely, to answer, was that of

the connection between our psychic states considered purely as such,

regardless of the objective connections of which they might take

cognizance. How does a man come, after thinking of A, to think of B

the next moment? or how does he come to think A and B always together?

These were the phenomena which Hartley undertook to explain by cerebral

physiology. I believe that he was, in many essential respects, on the

right track, and I propose simply to revise his conclusions by the aid

of distinctions which he did not make.

But the whole historic doctrine of psychological association is tainted

with one huge error--that of the construction of our thoughts out of

the confounding of themselves together of immutable and incessantly

recurring 'simple ideas.' It is the cohesion of these which the

'principles of association' are considered to account for. In Chapters

VI and IX we saw abundant reasons for treating the doctrine of simple

ideas or psychic atoms as mythological; and, in all that follows, our

problem will be to keep whatever truths the associationist doctrine has

caught sight of without weighing it down with the untenable incumbrance

that the association is between 'ideas.'

* * * * *

_Association_, so far as the word stands for an _effect, is between_

THINGS THOUGHT OF--_it is_ THINGS, _not ideas, which are associated in

the mind._ We ought to talk of the association of _objects_, not of the

association of _ideas_. And so far as association stands for a _cause_,

it is between _processes in the brain_--it is these which, by being

associated in certain ways, determine what successive objects shall be

thought. Let us proceed towards our final generalizations by surveying

first a few familiar facts.

* * * * *

The laws of motor habit in the lower centres of the nervous system

are disputed by no one. A series of movements repeated in a certain

order tend to unroll themselves with peculiar ease in that order for

ever afterward. Number one awakens number two, and that awakens number

three, and so on, till the last is produced. A habit of this kind

once become inveterate may go on automatically. And so it is with the

objects with which our thinking is concerned. With some persons each

note of a melody, heard but once, will accurately revive in its proper

sequence. Small boys at school learn the inflections of many a Greek

noun, adjective, or verb, from the reiterated recitations of the upper

classes falling on their ear as they sit at their desks. All this

happens with no voluntary effort on their part and with no thought of

the spelling of the words. The doggerel rhymes which children use in

their games, such as the formula

"Ana mana mona mike

Barcelona bona strike,"

used for 'counting out,' form another familiar example of things heard

in sequence cohering in the same order in the memory.

In touch we have a smaller number of instances, though probably every

one who bathes himself in a certain fixed manner is familiar with the

fact that each part of his body over which the water is squeezed from

the sponge awakens a premonitory tingling consciousness in that portion

of skin which is habitually the next to be deluged. Tastes and smells

form no very habitual series in our experience. But even if they did,

it is doubtful whether habit would fix the order of their reproduction

quite so well as it does that of other sensations. In vision, however,

we have a sense in which the order of reproduced things is very nearly

as much influenced by habit as is the order of remembered sounds.

Rooms, landscapes, buildings, pictures, or persons with whose look we

are very familiar, surge up before the mind's eye with all the details

of their appearance complete, so soon as we think of any one of their

component parts. Some persons, in reciting printed matter by heart,

will seem to see each successive word, before they utter it, appear in

its order on an imaginary page. A certain chess-player, one of those

heroes who train themselves to play several games at once blindfold,

is reported to say that in bed at night after a match the games are

played all over again before his mental eye, each board being pictured

as passing in turn through each of its successive stages. In this case,

of course, the intense previous voluntary strain of the power of visual

representation is what facilitated the fixed order of revival.

Association occurs as amply between impressions of different senses as

between homogeneous sensations. Seen things and heard things cohere

with each other, and with odors and tastes, in representation, in the

same order in which they cohered as impressions of the outer world.

Feelings of contact reproduce similarly the sights, sounds, and tastes

with which experience has associated them. In fact, the 'objects' of

our perception, as trees, men, houses, microscopes, of which the real

world seems composed, are nothing but clusters of qualities which

through simultaneous stimulation have so coalesced that the moment one

is excited actually it serves as a sign or cue for the idea of the

others to arise. Let a person enter his room in the dark and grope

among the objects there. The touch of the matches will instantaneously

recall their appearance. If his hand comes in contact with an orange

on the table, the golden yellow of the fruit, its savor and perfume

will forthwith shoot through his mind. In passing the hand over the

sideboard or in jogging the coal-scuttle with the foot, the large

glossy dark shape of the one and the irregular blackness of the other

awaken like a flash and constitute what we call the recognition of the

objects. The voice of the violin faintly echoes through the mind as the

hand is laid upon it in the dark, and the feeling of the garments or

draperies which may hang about the room is not _understood_ till the

look correlative to the feeling has in each case been resuscitated.

Smells notoriously have the power of recalling the other experiences in

whose company they were wont to be felt, perhaps long years ago; and

the voluminous emotional character assumed by the images which suddenly

pour into the mind at such a time forms one of the staple topics of

popular psychologic wonder--

"Lost and gone and lost and gone!

A breath, a whisper--some divine farewell--

Desolate sweetness--far and far away."

We cannot hear the din of a railroad tram or the yell of its whistle,

without thinking of its long, jointed appearance and its headlong

speed, nor catch a familiar voice in a crowd without recalling, with

the name of the speaker, also his face. But the most notorious and

important case of the mental combination of auditory with optical

impressions originally experienced together is furnished by language.

The child is offered a new and delicious fruit and is at the same

time told that it is called a 'fig.' Or looking out of the window he

exclaims, "What a funny horse!" and is told that it is a 'piebald'

horse. When learning his letters, the sound of each is repeated to him

whilst its shape is before his eye. Thenceforward, long as he may live,

he will never see a fig, a piebald horse, or a letter of the alphabet

without the name which he first heard in conjunction with each clinging

to it in his mind; and inversely he will never hear the name without

the faint arousal of the image of the object.[465]

THE RAPIDITY OF ASSOCIATION.

Reading exemplifies this kind of cohesion even more beautifully. It is

an uninterrupted and protracted recall of sounds by sights which have

always been coupled with them in the past. I find that I can name six

hundred letters in two minutes on a printed page. Five distinct acts

of association between sight and sound (not to speak of all the other

processes concerned) must then have occurred in each second in my mind.

In reading entire words the speed is much more rapid. Valentin relates

in his Physiology that the reading of a single page of the proof,

containing 2629 letters, took him 1 minute and 32 seconds. In this

experiment each letter was _understood_ in 1/28 of a second, but owing

to the integration of letters into entire words, forming each a single

aggregate impression directly associated with a single acoustic image,

we need not suppose as many as 28 separate associations in a sound. The

figures, however, suffice to show with what extreme rapidity an actual

sensation recalls its customary associates. Both in fact seem to our

ordinary attention to come into the mind at once.

The time-measuring psychologists of recent days have tried their

hand at this problem by more elaborate methods. Galton, using a very

simple apparatus, found that the sight of an unforeseen word would

awaken an associated 'idea' in about 5/6 of a second.[466] Wundt next

made determinations in which the 'cue' was given by single-syllabled

words called out by an assistant. The person experimented on had to

press a key as soon as the sound of the word awakened an associated

idea. Both word and reaction were chronographically registered, and

the total time-interval between the two amounted, in four observers,

to 1.009, 0.896, 1.037, and 1.154 seconds respectively. From this the

simple physiological reaction-time and the time of merely identifying

the word's sound (the 'apperception-time,' as Wundt calls it) must be

subtracted, to get the exact time required for the associated idea

to arise. These times were separately determined and subtracted. The

difference, called by Wundt the _association-time_, amounted, in the

same four persons, to 706, 723, 752, and 874 thousandths of a second

respectively.[467] The length of the last figure is due to the fact

that the person reacting (President G. S. Hall) was an American,

whose associations with German words would naturally be slower than

those of natives. The shortest association-time noted was when the

word 'Sturm' suggested to Prof. Wundt the word 'Wind' in 0.341

second.[468]--Finally, Mr. Cattell made some interesting observations

upon the association-time between the look of letters and their names.

"I pasted letters," he says, "on a revolving drum, and determined

at what rate they could be read aloud as they passed by a slit in a

screen." He found it to vary according as one, or more than one letter,

was visible at a time through the slit, and gives half a second as

about the time which it takes to see and name a single letter seen

alone.

"When two or more letters are always in view, not only do the

processes of seeing and naming overlap, but while the subject is

seeing one letter he begins to see the ones next following, and so

can read them more quickly. Of the nine persons experimented on, four

could read the letters faster when five were in view at once, but were

not helped by a sixth letter; three were not helped by a fifth, and

two not by a fourth letter. This shows that while one idea is in the

centre, two, three, or four additional ideas may be in the background

of consciousness. The second letter in view shortens the time about

1/40, the third 1/60, the fourth 1/100, the fifth 1/200 sec.

"I find it takes about twice as long to read (aloud, as fast as

possible) words which have no connection as words which make sentences

and letters which have no connection as letters which make words.

When the words make sentences and the letters words, not only do the

processes of seeing and naming overlap, but by one mental effort the

subject can recognize a whole group of words or letters, and by one

will-act choose the motions to be made in naming, so that the rate

at which the words and letters are read is really only limited by

the maximum rapidity at which the speech-organs can be moved. As the

result of a large number of experiments, the writer found that he had

read words not making sentences at the rate of 1/4 sec, words making

sentences (a passage from Swift) at the rate of 1/8 sec., per word....

The rate at which a person reads a foreign language is proportional to

his familiarity with the language. For example, when reading as fast

as possible the writer's rate was, English 138, French 167, German

250, Italian 327, Latin 434, and Greek 484; the figures giving the

thousandths of a second taken to read each word. Experiments made on

others strikingly confirm these results. The subject does not know

that he is reading the foreign language more slowly than his own; this

explains why foreigners seem to talk so fast. This simple method of

determining a person's familiarity with a language might be used in

school examinations.

"The time required to see and name colors and pictures of objects was

determined in the same way. The time was found to be about the same

(over 1/2 sec.) for colors as for pictures, and about twice as long

as for words and letters. Other experiments I have made show that we

can recognize a single color or picture in a slightly shorter time

than a word or letter, but take longer to name it. This is because, in

the case of words and letters, the association between the idea and

name has taken place so often that the process has become automatic,

whereas in the case of colors and pictures we must by a voluntary

effort choose the name."[469]

In later experiments Mr. Cattell studied the time for various

associations to be performed, the termini (i.e., cue and answer) being

words. A word in one language was to call up its equivalent in another,

the name of an author the tongue in which he wrote, that of a city the

country in which it lay, that of a writer one of his works, etc. The

mean variation from the average is very great in all these experiments;

and the interesting feature which they show is the existence of

certain constant differences between associations of different sorts.

Thus:

From _country_ to _city_, Mr. C.'s time was 0.340 sec.

From _season_ to _month_, Mr. C.'s time was 0.399

From _language_ to _author_, Mr. C.'s time was 0.523

From _author_ to _work_, Mr. C.'s time was 0.596

The average time of two observers, experimenting on eight different

types of association, was 0.420 and 0.436 sec. respectively.[470] The

very wide range of variation is undoubtedly a consequence of the fact

that the words used as cues, and the different types of association

studied, differ much in their degree of familiarity.

"For example, B is a teacher of mathematics; C has busied himself more

with literature. C knows quite as well as B that 7 + 5 = 12, yet he

needs 1/10 a second longer to call it to mind; B knows quite as well

as C that Dante was a poet, but needs 1/20 of a second longer to think

of it. Such experiments lay bare the mental life in a way that is

startling and not always gratifying."[471]

THE LAW OF CONTIGUITY.

Time-determinations apart, the facts we have run over can all be summed

up in the simple statement that _objects once experienced together tend

to become associated in the imagination, so that when any one of them

is thought of, the others are likely to be thought of also, in the same

order of sequence or coexistence as before_. This statement we may name

the law of _mental association by contiguity_.[472]

I preserve this name in order to depart as little as possible from

tradition, although Mr. Ward's designation of the process as that of

association by _continuity_[473] or Wundt's as that of _external_

association (to distinguish it from the _internal_ association which

we shall presently learn to know under the name of association by

similarity)[474] are perhaps better terms. Whatever we name the law,

since it expresses merely a phenomenon of mental _habit, the most

natural way of accounting for it is to conceive it as a result of

the laws of habit in the nervous system; in other words, it is to

ascribe it to a physiological cause._ If it be truly a law of those

nerve-centres which co-ordinate sensory and motor processes together

that paths once used for coupling any pair of them are thereby made

more permeable, there appears no reason why the same law should not

hold good of ideational centres and their coupling-paths as well.[475]

Parts of these centres which have once been in action together will

thus grow so linked that excitement at one point will irradiate

through the system. The chances of complete irradiation will be

strong in proportion as the previous excitements have been frequent,

and as the present points excited afresh are numerous. If all points

were originally excited together, the irradiation may be sensibly

simultaneous throughout the system, when any single point or group

of points is touched off. But where the original impressions were

successive--the conjugation of a Greek verb, for example--awakening

nerve-tracts in a definite order, they will now, when one of them

awakens, discharge into each other in that definite order and in no

other way.

The reader will recollect all that has been said of increased tension

in nerve-tracts and of the summation of stimuli (p. 82 ff.). We must

therefore suppose that in these ideational tracts as well as elsewhere,

activity may be awakened, in any particular locality, by the summation

therein of a number of tensions, each incapable alone of provoking

an actual discharge. Suppose for example the locality M to be in

functional continuity with four other localities, K, L, N, and O.

Suppose moreover that on four previous occasions it has been separately

combined with each of these localities in a common activity. M may then

be indirectly awakened by any cause which tends to awaken either K, L,

N, or O. But if the cause which awakens K, for instance, be so slight

as only to increase its tension without arousing it to full discharge,

K will only succeed in slightly increasing the tension of M. But if at

the same time the tensions of L, N, and O are similarly increased, the

combined effects of all four upon M may be so great as to awaken an

actual discharge in this latter locality. In like manner if the paths

between M and the four other localities have been so slightly excavated

by previous experience as to require a very intense excitement in

either of the localities before M can be awakened, a less strong

excitement than this in any one will fail to reach M. But if all four

at once are mildly excited, their compound effect on M may be adequate

to its full arousal.

_The psychological law of association_ of objects thought of through

their previous contiguity in thought or experience _would thus be an

effect, within the mind, of the physical fact that nerve-currents

propagate themselves easiest through those tracts of conduction which

have been already most in use._ Descartes and Locke hit upon this

explanation, which modern science has not yet succeeded in improving.

"Custom," says Locke, "settles habits of thinking in the

understanding, as well as of determining in the will, and of motions

in the body; all which seem to be but _trains of motion in the animal

spirits_ [by this Locke meant identically what we understand by

_neural processes_] which, once set agoing, continue in the same steps

they have been used to, which by often treading are worn into a smooth

path, and the motion in it becomes easy and, as it were, natural."[476]

Hartley was more thorough in his grasp of the principle. The sensorial

nerve-currents, produced when objects are fully present, were for

him 'vibrations,' and those which produce ideas of objects in their

absence were 'miniature vibrations.' And he sums up the cause of mental

association in a single formula by saying:

"Any vibrations, A, B, C, etc., by being associated together a

sufficient Number of Times, get such a Power over _a, b, c,_ etc., the

corresponding Miniature Vibrations, that any of the Vibrations A, when

impressed alone, shall be able to excite _b, c,_ etc., the Miniatures

of the rest."[477]

It is evident that if there be any law of neural habit similar to

this, the contiguities, coexistences, and successions, met with in

outer experience, must inevitably be copied more or less perfectly in

our thought. If A B C D E be a sequence of outer impressions (they

may be events or they may be successively experienced properties of

an object) which once gave rise to the successive 'ideas' _a b c d

e_, then no sooner will A impress us again and awaken the _a_, than

_b c d e_ will arise as ideas even before B C D E have come in as

impressions. In other words, the order of impressions will the next

time be _anticipated_; and the mental order will so far forth copy the

order of the outer world. Any object when met again will make us expect

its former concomitants, through the overflowing of its brain-tract

into the paths which lead to theirs. And all these suggestions will be

effects of a material law.

Where the associations are, as here, of successively appearing things,

the distinction I made at the outset of the chapter, between a

connection _thought of_ and a connection _of thoughts_, is unimportant.

For the connection thought of is concomitance or succession; and the

connection between the thoughts is just the same. The 'objects' and the

'ideas' fit into parallel schemes, and may be described in identical

language, as contiguous things tending to be thought again together, or

contiguous ideas tending to recur together.

Now were these cases fair samples of all association, the distinction

I drew might well be termed a _Spitzfindigkeit_ or piece of pedantic

hair-splitting, and be dropped. But as a matter of fact we cannot treat

the subject so simply. The same outer object may suggest _either of

many_ realities formerly associated with it--for in the vicissitudes of

our outer experience we are constantly liable to meet the same thing

in the midst of differing companions--and a philosophy of association

that should merely say that it will suggest one of these, or even of

that one of them which it has oftenest accompanied, would go but a

very short way into the _rationale_ of the subject. This, however, is

about as far as most associationists have gone with their 'principle

of contiguity.' Granted an object, A, they never tell us beforehand

which of its associates it _will_ suggest; their wisdom is limited to

showing, after it _has_ suggested a second object, that that object

was once an associate. They have had to supplement their principle

of Contiguity by other principles, such as those of Similarity and

Contrast, before they could begin to do justice to the richness of the

facts.

THE ELEMENTARY LAW OF ASSOCIATION.

I shall try to show, in the pages which immediately follow, that there

is no other _elementary_ causal law of association than the law of

neural habit. All the _materials_ of our thought are due to the way

in which one elementary process of the cerebral hemispheres tends to

excite whatever other elementary process it may have excited at some

former time. The number of elementary processes at work, however, and

the nature of those which at any time are fully effective in rousing

the others, determine the character of the total brain-action, and,

as a consequence of this, they determine the object thought of at the

time. According as this resultant object is one thing or another, we

call it a product of association by contiguity or of association by

similarity, or contrast, or whatever other sorts we may have recognized

as ultimate. Its production, however, is, in each one of these cases,

to be explained by a merely quantitative variation in the elementary

brain-processes momentarily at work under the law of habit, so that

_psychic_ contiguity, similarity, etc., are derivatives of a single

profounder kind of fact.

My thesis, stated thus briefly, will soon become more clear; and at the

same time certain disturbing factors, which co-operate with the law of

neural habit, will come to view.

Let us then assume as the _basis_ of all our subsequent reasoning this

law: _When two elementary brain-processes have been active together

or in immediate succession, one of them, on reoccurring, tends to

propagate its excitement into the other._

But, as a matter of fact, every elementary process has found itself at

different times excited in conjunction with _many_ other processes,

and this by unavoidable outward causes. Which of these others it shall

awaken now becomes a problem. Shall _b_ or _c_ be aroused next by the

present _a_? We must make a further postulate, based, however, on

the fact of _tension_ in nerve-tissue, and on the fact of summation

of excitements, each incomplete or latent in itself, into an open

resultant.[478] The process _b_, rather than _c_, will awake, if in

addition to the vibrating tract _a_ some other tract _d_ is in a state

of sub-excitement, and formerly was excited with _b_ alone and not with

_a_. In short, we may say:

_The amount of activity at any given point in the brain-cortex is

the sum of the tendencies of all other points to discharge into it,

such tendencies being proportionate_ (1) _to the number of times the

excitement of each other point may have accompanied that of the point

in question_; (2) _to the intensity of such excitements; and_ (3) _to

the absence of any rival point functionally disconnected with the first

point, into which the discharges might be diverted._

Expressing the fundamental law in this most complicated way leads to

the greatest ultimate simplification. Let us, for the present, only

treat of spontaneous trains of thought and ideation, such as occur in

revery or musing. The case of voluntary thinking toward a certain end

shall come up later.

Take, to fix our ideas, the two verses from 'Locksley Hall':

"I, the heir of all _the ages_ in the foremost files of time,"

and--

"For I doubt not through _the ages_ one increasing purpose runs."

Why is it that when we recite from memory one of these lines, and get

as far as _the ages_, that portion of the _other_ line which follows,

and, so to speak, sprouts out of _the ages_, does not also sprout out

of our memory, and confuse the sense of our words? Simply because

the word that follows _the ages_ has its brain-process awakened not

simply by the brain-process of _the ages_ alone, but by it _plus_ the

brain-processes of all the words preceding _the ages_. The word _ages_

at its moment of strongest activity would, _per se_, indifferently

discharge into either 'in' or 'one.' So would the previous words (whose

tension is momentarily much less strong than that of _ages_) each of

them indifferently discharge into either of a large number of other

words with which they have been at different times combined. But when

the processes of '_I, the heir of all the ages_,' simultaneously

vibrate in the brain, the last one of them in a maximal, the others in

a fading phase of excitement; then the strongest line of discharge will

be that which they _all alike_ tend to take. '_In_' and not '_one_' or

any other word will be the next to awaken, for its brain-process has

previously vibrated in unison not only with that of _ages_, but with

that of all those other words whose activity is dying away. It is a

good case of the effectiveness over thought of what we called on p. 258

a 'fringe.'

But if some one of these preceding words--'heir,' for example--had an

intensely strong association with some brain-tracts entirely disjoined

in experience from the poem of 'Locksley Hall'--if the reciter, for

instance, were tremulously awaiting the opening of a will which might

make him a millionaire--it is probable that the path of discharge

through the words of the poem would be suddenly interrupted at the word

'heir.' His _emotional interest in that word_ would be such that its

_own special associations would prevail_ over the combined ones of the

other words. He would, as we say, be abruptly reminded of his personal

situation, and the poem would lapse altogether from his thoughts.

The writer of these pages has every year to learn the names of a large

number of students who sit in alphabetical order in a lecture-room. He

finally learns to call them by name, as they sit in their accustomed

places. On meeting one in the street, however, early in the year, the

face hardly ever recalls the name, but it may recall the place of its

owner in the lecture-room, his neighbors' faces, and consequently

his general alphabetical position; and then, usually as the common

associate of all these combined data, the student's name surges up in

his mind.

A father wishes to show to some guests the progress of his rather dull

child in Kindergarten instruction. Holding the knife upright on the

table, he says, "What do you call that, my boy?" "I calls it a _knife_,

I does," is the sturdy reply, from which the child cannot be induced

to swerve by any alteration in the form of question, until the father

recollecting that in the Kindergarten a pencil was used, and not a

knife, draws a long one from his pocket, holds it in the same way,

and then gets the wished-for answer, "I calls it _vertical_." All the

concomitants of the Kindergarten experience had to recombine their

effect before the word 'vertical' could be reawakened.

Professor Bain, in his chapters on 'Compound Association,' has treated

in a minute and exhaustive way of this type of mental sequence, and

what he has done so well need not be here repeated.[479]

_Impartial Redintegration._

The ideal working of the law of compound association, were it

unmodified by any extraneous influence, would be such as to keep the

mind in a perpetual treadmill of concrete reminiscences from which no

detail could be omitted. Suppose, for example, we begin by thinking

of a certain dinner-party. The only thing which all the components of

the dinner-party could combine to recall would be the first concrete

occurrence which ensued upon it. All the details of this occurrence

could in turn only combine to awaken the next following occurrence, and

so on. If _a, b, c, d, e,_ for instance, be the elementary nerve-tracts

excited by the last act of the dinner-party, call this act A, and _l,

m, n, o, p,_ be those of walking home through the frosty night, which

we may call B, then the thought of A must awaken that of B, because

_a, b, c, d, e,_ will each and all discharge into _l_ through the

paths by which their original discharge took place. Similarly they

will discharge into _m, n, o,_ and _p_; and these latter tracts will

also each reinforce the other's action because, in the experience B,

they have already vibrated in unison. The lines in Fig. 40 symbolize

the summation of discharges into each of the components of B, and the

consequent strength of the combination of influences by which B in its

totality is awakened.

Hamilton first used the word 'redintegration' to designate all

association. Such processes as we have just described might in an

emphatic sense be termed redintegrations, for they would necessarily

lead, if unobstructed, to the reinstatement in thought of the _entire_

content of large trains of past experience. From this complete

redintegration there could be no escape save through the irruption

of some new and strong present impression of the senses, or through

the excessive tendency of some one of the elementary brain-tracts to

discharge independently into an aberrant quarter of the brain. Such

was the tendency of the word 'heir' in the verse from 'Locksley Hall,'

which was our first example. How such tendencies are constituted we

shall have soon to inquire with some care. Unless they are present,

the panorama of the past, once opened, must unroll itself with fatal

literality to the end, unless some outward sound, sight, or touch

divert the current of thought.

[Illustration: FIG. 40.]

Let us call this process _impartial redintegration_. Whether it ever

occurs in an absolutely complete form is doubtful. We all immediately

recognize, however, that in some minds there is a much greater tendency

than in others for the flow of thought to take this form. Those

insufferably garrulous old women, those dry and fanciless beings who

spare you no detail, however petty, of the facts they are recounting,

and upon the thread of whose narrative all the irrelevant items cluster

as pertinaciously as the essential ones, the slaves of literal fact,

the stumblers over the smallest abrupt step in thought, are figures

known to all of us. Comic literature has made her profit out of

them. Juliet's nurse is a classical example. George Eliot's village

characters and some of Dickens's minor personages supply excellent

instances.

Perhaps as successful a rendering as any of this mental type is

the character of Miss Bates in Miss Austen's 'Emma.' Hear how she

redintegrates:

"'But where could _you_ hear it?' cried Miss Bates. 'Where could you

possibly hear it, Mr. Knightley? For it is not five minutes since I

received Mrs. Cole's note--no, it cannot be more than five--or at

least ten--for I had got my bonnet and spencer on, just ready to come

out--I was only gone down to speak to Patty again about the pork--Jane

was standing in the passage--were not you, Jane?--for my mother was

so afraid that we had not any salting-pan large enough. So I said

I would go down and see, and Jane said: "Shall I go down instead?

for I think you have a little cold, and Patty has been washing the

kitchen." "Oh, my dear," said I--well, and just then came the note.

A Miss Hawkins--that's all I know--a Miss Hawkins, of Bath. But, Mr.

Knightley, how could you possibly have heard it? for the very moment

Mr. Cole told Mrs. Cole of it, she sat down and wrote to me. A Miss

Hawkins--'"

But in every one of us there are moments when this complete

reproduction of all the items of a past experience occurs. What are

those moments? They are moments of emotional recall of the past as

something which once was, but is gone for ever--moments, the interest

of which consists in the feeling that our self was once other than

it now is. When this is the case, any detail, however minute, which

will make the past picture more complete, will also have its effect in

swelling that total contrast between _now_ and _then_ which forms the

central interest of our contemplation.

ORDINARY OR MIXED ASSOCIATION.

This case helps us to understand why it is that the ordinary

spontaneous flow of our ideas does not follow the law of impartial

redintegration. _In no revival of a past experience are all the

items of our thought equally operative in determining what the next

thought shall be. Always some ingredient is prepotent over the rest._

Its special suggestions or associations in this case will often be

different from those which it has in common with the whole group of

items; and its tendency to awaken these outlying associates will

deflect the path of our revery. Just as in the original sensible

experience our attention focalized itself upon a few of the impressions

of the scene before us, so here in the reproduction of those

impressions an equal partiality is shown, and some items are emphasized

above the rest. What these items shall be is, in most cases of

spontaneous revery, hard to determine beforehand. In subjective terms

we say that _the prepotent items are those which appeal most to our_

INTEREST.

Expressed in brain-terms, the law of interest will be: _some one

brain-process is always prepotent above its concomitants in arousing

action elsewhere._

"Two processes," says Mr. Hodgson,[480] "are constantly going on

in redintegration. The one a process of corrosion, melting, decay;

the other a process of renewing, arising, becoming.... No object of

representation remains long before consciousness in the same state,

but fades, decays, and becomes indistinct. Those parts of the object,

however, which possess an interest resist this tendency to gradual

decay of the whole object.... This inequality in the object--some

parts, the uninteresting, submitting to decay; others, the interesting

parts, resisting it--when it has continued for a certain time, ends in

becoming a new object."

Only where the interest is diffused equally over all the parts (as

in the emotional memory just referred to, where, as all _past_, they

all interest us alike) is this law departed from. It will be least

obeyed by those minds which have the smallest variety and intensity

of interests--those who, by the general flatness and poverty of their

æsthetic nature, are kept for ever rotating among the literal sequences

of their local and personal history.

Most of us, however, are better organized than this, and our musings

pursue an erratic course, swerving continually into some new direction

traced by the shifting play of interest as it ever falls on some

partial item in each complex representation that is evoked. Thus it

so often comes about that we find ourselves thinking at two nearly

adjacent moments of things separated by the whole diameter of space

and time. Not till we carefully recall each step of our cogitation do

we see how naturally we came by Hodgson's law to pass from one to the

other. Thus, for instance, after looking at my clock just now (1879),

I found myself thinking of a recent resolution in the Senate about our

legal-tender notes. The clock called up the image of the man who had

repaired its gong. He suggested the jeweller's shop where I had last

seen him; that shop, some shirt-studs which I had bought there; they,

the value of gold and its recent decline; the latter, the equal value

of greenbacks, and this, naturally, the question of how long they were

to last, and of the Bayard proposition. Each of these images offered

various points of interest. Those which formed the turning-points of

my thought are easily assigned. The gong was momentarily the most

interesting part of the clock, because, from having begun with a

beautiful tone, it had become discordant and aroused disappointment.

But for this the clock might have suggested the friend who gave it to

me, or any one of a thousand circumstances connected with clocks. The

jeweller's shop suggested the studs, because they alone of all its

contents were tinged with the egoistic interest of possession. This

interest in the studs, their value, made me single out the material

as its chief source, etc., to the end. Every reader who will arrest

himself at any moment and say, "How came I to be thinking of just

this?" will be sure to trace a train of representations linked together

by lines of contiguity and points of interest inextricably combined.

This is the ordinary process of the association of ideas as it

spontaneously goes on in average minds. _We may call it_ ORDINARY, _or_

MIXED, ASSOCIATION.

Another example of it is given by Hobbes in a passage which has been

quoted so often as to be classical:

"In a discourse of our present civil war, what could seem more

impertinent than to ask (as one did) what was the value of a Roman

penny? Yet the coherence to me was manifest enough. For the thought of

the war introduced the thought of the delivering up the King to his

enemies; the thought of that brought in the thought of the delivering

up of Christ; and that again the thought of the thirty pence, which

was the price of that treason: and thence easily followed that

malicious question; and all this in a moment of time; for thought is

quick."[481]

Can we determine, now, when a certain portion of the going thought

has, by dint of its interest, become so prepotent as to make its own

exclusive associates the dominant features of the coming thought--can

we, I say, determine _which_ of its own associates shall be evoked? For

they are many. As Hodgson says:

"The interesting parts of the decaying object are free to combine

again with any objects or parts of objects with which at any time they

have been combined before. All the former combinations of these parts

may come back into consciousness; one must; but which will?"

Mr. Hodgson replies:

"There can be but one answer: that which has been most _habitually_

combined with them before. This new object begins at once to form

itself in consciousness, and to group its parts round the part still

remaining from the former object; part after part comes out and

arranges itself in its old position; but scarcely has the process

begun, when the original law of interest begins to operate on this

new formation, seizes on the interesting parts and impresses them on

the attention to the exclusion of the rest, and the whole process is

repeated again with endless variety. I venture to propose this as a

complete and true account of the whole process of redintegration."

In restricting the discharge from the interesting item into that

channel which is simply most _habitual_ in the sense of most frequent,

Hodgson's account is assuredly imperfect. An image by no means always

revives its most frequent associate, although frequency is certainly

one of the most potent determinants of revival. If I abruptly utter

the word _swallow_, the reader, if by habit an ornithologist, will

think of a bird; if a physiologist or a medical specialist in throat

diseases, he will think of deglutition. If I say _date_, he will, if

a fruit-merchant or an Arabian traveller, think of the produce of the

palm; if an habitual student of history, figures with A.D. or B.C.

before them will rise in his mind. If I say _bed, bath, morning,_

his own daily toilet will be invincibly suggested by the combined

names of three of its habitual associates. But frequent lines of

transition are often set at naught. The sight of C. Goring's 'System

der kritischen Philosophie' has most frequently awakened in me thoughts

of the opinions therein propounded. The idea of suicide has never been

connected with the volumes. But a moment since, as my eye fell upon

them, suicide was the thought that flashed into my mind. Why? Because

but yesterday I received a letter from Leipzig informing me that this

philosopher's recent death by drowning was an act of self-destruction.

Thoughts tend, then, to awaken their most recent as well as their most

habitual associates. This is a matter of notorious experience, too

notorious, in fact, to need illustration. If we have seen our friend

this morning, the mention of his name now recalls the circumstances

of that interview, rather than any more remote details concerning

him. If Shakespeare's plays are mentioned, and we were last night

reading 'Richard II.,' vestiges of that play rather than of 'Hamlet'

or 'Othello' float through our mind. Excitement of peculiar tracts,

or peculiar modes of general excitement in the brain, leave a sort of

tenderness or exalted sensibility behind them which takes days to die

away. As long as it lasts, those tracts or those modes are liable to

have their activities awakened by causes which at other times might

leave them in repose. Hence, _recency_ in experience is a prime factor

in determining revival in thought.[482]

_Vividness_ in an original experience may also have the same effect as

habit or recency in bringing about likelihood of revival. If we have

once witnessed an execution, any subsequent conversation or reading

about capital punishment will almost certainly suggest images of that

particular scene. Thus it is that events lived through only once, and

in youth, may come in after-years, by reason of their exciting quality

or emotional intensity, to serve as types or instances used by our

mind to illustrate any and every occurring topic whose interest is

most remotely pertinent to theirs. If a man in his boyhood once talked

with Napoleon, any mention of great men or historical events, battles

or thrones, or the whirligig of fortune, or islands in the ocean,

will be apt to draw to his lips the incidents of that one memorable

interview. If the word _tooth_ now suddenly appears on the page before

the reader's eye, there are fifty chances out of a hundred that, if

he gives it time to awaken any image, it will be an image of some

operation of dentistry in which he has been the sufferer. Daily he

has touched his teeth and masticated with them; this very morning he

brushed them, chewed his breakfast and picked them; but the rarer and

remoter associations arise more promptly because they were so much more

intense.[483]

A fourth factor in tracing the course of reproduction is _congruity

in emotional tone_ between the reproduced idea and our mood. The same

objects do not recall the same associates when we are cheerful as when

we are melancholy. Nothing, in fact, is more striking than our utter

inability to keep up trains of joyous imagery when we are depressed

in spirits. Storm, darkness, war, images of disease, poverty, and

perishing afflict unremittingly the imaginations of melancholiacs.

And those of sanguine temperament, when their spirits are high, find

it impossible to give any permanence to evil forebodings or to gloomy

thoughts. In an instant the train of association dances off to flowers

and sunshine, and images of spring and hope. The records of Arctic or

African travel perused in one mood awaken no thoughts but those of

horror at the malignity of Nature; read at another time they suggest

only enthusiastic reflections on the indomitable power and pluck of

man. Few novels so overflow with joyous animal spirits as 'The Three

Guardsmen' of Dumas. Yet it may awaken in the mind of a reader

depressed with sea-sickness (as the writer can personally testify) a

most dismal and woeful consciousness of the cruelty and carnage of

which heroes like Athos, Porthos, and Aramis make themselves guilty.

_Habit, recency, vividness, and emotional congruity_ are, then, all

reasons why one representation rather than another should be awakened

by the interesting portion of a departing thought. We may say with

truth that _in the majority of cases the coming representation will

have been either habitual, recent, or vivid, and will be congruous._ If

all these qualities unite in any one absent associate, we may predict

almost infallibly that that associate of the going thought will form

an important ingredient in the coming thought. In spite of the fact,

however, that the succession of representations is thus redeemed from

perfect indeterminism and limited to a few classes whose characteristic

quality is fixed by the nature of our past experience, it must still

be confessed that an immense number of terms in the linked chain of

our representations fall outside of all assignable rule. To take

the instance of the clock given on page 586. Why did the jeweller's

shop suggest the shirt-studs rather than a chain which I had bought

there more recently, which had cost more, and whose sentimental

associations were much more interesting? Both chain and studs had

excited brain-tracts simultaneously with the shop. The only reason why

the nerve-stream from the shop-tract switched off into the stud-tract

rather than into the chain-tract must be that the stud-tract happened

at that moment to lie more open, either because of some accidental

alteration in its nutrition or because the incipient sub-conscious

tensions of the brain as a whole had so distributed their equilibrium,

that it was more unstable here than in the chain-tract. Any reader's

introspection will easily furnish similar instances. It thus remains

true that to a certain extent, even in those forms of ordinary mixed

association which lie nearest to impartial redintegration, _which_

associate of the interesting item shall emerge must be called largely a

matter of accident--accident, that is, for our intelligence. No doubt

it is determined by cerebral causes, but they are too subtile and

shifting for our analysis.

ASSOCIATION BY SIMILARITY.

In partial or mixed association we have all along supposed the

interesting portion of the disappearing thought to be of considerable

extent, and to be sufficiently complex to constitute by itself a

concrete object. Sir William Hamilton relates, for instance, that

after thinking of Ben Lomond he found himself thinking of the Prussian

system of education, and discovered that the links of association

were a German gentleman whom he had met on Ben Lomond, Germany, etc.

The interesting part of Ben Lomond, as he had experienced it, the

part operative in determining the train of his ideas was the complex

image of a particular man. But now let us suppose that that selective

agency of interested attention, which may thus convert impartial

redintegration into partial association--let us suppose that it refines

itself still further and accentuates a portion of the passing thought,

so small as to be no longer the image of a concrete thing, but only

of an abstract quality or property. Let us moreover suppose that the

part thus accentuated persists in consciousness (or, in cerebral

terms, has its brain-process continue) after the other portions of the

thought have faded. _This small surviving portion will then surround

itself with its own associates_ after the fashion we have already

seen, and the relation between the new thought's object and the object

of the faded thought will be a _relation of similarity_. The pair of

thoughts will form an instance of what is called '_Association by

Similarity_.'[484]

The similars which are here associated, or of which the first is

followed by the second in the mind, are seen to be _compounds_.

Experience proves that this is always the case. _There is no tendency

on the part of_ SIMPLE _'ideas,' attributes, or qualities to remind us

of their like._ The thought of one shade of blue does not remind us of

that of another shade of blue, etc., unless indeed we have in mind some

general purpose like naming the tint, when we should naturally think

of other blues of the scale, through 'mixed association' of purpose,

names, and tints, together. But there is no elementary tendency of pure

qualities to awaken their similars in the mind.

We saw in the chapter on Discrimination that two compound things are

similar when some one quality or group of qualities is shared alike by

both, although as regards their other qualities they may have nothing

in common. The moon is similar to a gas-jet, it is also similar to a

foot-ball; but a gas-jet and a foot-ball are not similar to each other.

When we affirm the similarity of two compound things, we should always

say _in what respect it obtains_. Moon and gas-jet are similar in

respect of luminosity, and nothing else; moon and foot-ball in respect

of rotundity, and nothing else. Foot-ball and gas-jet are in no respect

similar--that is, they possess no common point, no identical attribute.

Similarity, in compounds, is partial identity. When the _same_

attribute appears in two phenomena, though it be their only common

property, the two phenomena are similar in so far forth. To return

now to our associated representations. If the thought of the moon is

succeeded by the thought of a foot-ball, and that by the thought of one

of Mr. X's railroads, it is because the attribute rotundity in the moon

broke away from all the rest and surrounded itself with an entirely new

set of companions--elasticity, leathery integument, swift mobility in

obedience to human caprice, etc.; and because the last-named attribute

in the foot-ball in turn broke away from its companions, and, itself

persisting, surrounded itself with such new attributes as make up the

notions of a 'railroad king,' of a rising and falling stock-market, and

the like.

The gradual passage from impartial redintegration to similar

association through what we have called ordinary mixed association may

be symbolized by diagrams. Fig. 41 is impartial redintegration, Fig. 42

is mixed, and Fig. 43 similar association. A in each is the passing,

B the coming thought. In 'impartial,' all parts of A are equally

operative in calling up B. In 'mixed,' most parts of A are inert. The

part M alone breaks out and awakens B. In 'similar,' the focalized

part M is much smaller than in the previous case, and after awakening

its new set of associates, instead of fading out itself, it continues

persistently active along with them, forming an identical part in the

two ideas, and making these, _pro tanto_, resemble each other.

[Illustration: FIG. 41.]

[Illustration: FIG. 42.]

[Illustration: FIG. 43.]

Why a single portion of the passing thought should break out from its

concert with the rest and act, as we say, on its own hook, why the

other parts should become inert, are mysteries which we can ascertain

but not explain. Possibly a minuter insight into the laws of neural

action will some day clear the matter up; possibly neural laws will

not suffice, and we shall need to invoke a dynamic reaction of the form

of consciousness upon its content. But into this we cannot enter now.

* * * * *

To sum up, then, we see that _the difference between the three kinds

of association reduces itself to a simple difference in the amount

of that portion of the nerve-tract supporting the going thought

which is operative in calling up the thought which comes._ But the

_modus operandi_ of this active part is the same, be it large or be

it small. The items constituting the coming object waken in every

instance because their nerve-tracts once were excited continuously

with those of the going object or its operative part. This ultimate

physiological law of habit among the neural elements is what _runs_ the

train. The direction of its course and the form of its transitions,

whether redintegrative, associative, or similar, are due to unknown

regulative or determinative conditions which accomplish their effect by

opening this switch and closing that, setting the engine sometimes at

half-speed, and coupling or uncoupling cars.

This last figure of speech, into which I have glided unwittingly,

affords itself an excellent instance of association by similarity.

I was thinking of the deflections of the course of ideas. Now, from

Hobbes's time downward, English writers have been fond of speaking of

the _train_ of our representations. This word happened to stand out in

the midst of my complex thought with peculiarly sharp accentuation, and

to surround itself with numerous details of railroad imagery. Only such

details became clear, however, as had their nerve-tracts besieged by a

double set of influences--those from _train_ on the one hand, and those

from the _movement of thought_ on the other. It may possibly be that

the prepotency of the suggestions of the word _train_ at this moment

were due to the recent excitation of the railroad brain-tract by the

instance chosen a few pages back of ii railroad king playing foot-ball

with the stock-market.

It is apparent from such an example how inextricably complex are all

the contributory factors whose resultant is the line of our reverie.

It would be folly in most cases to attempt to trace them out. From an

instance like the above, where the pivot of the Similar Association

was formed by a definite concrete word, _train_, to those where it is

so subtile as utterly to elude our analysis, the passage is unbroken.

We can form a series of examples. When Mr. Bagehot says that the mind

of the savage, so far from being in a state of nature, is _tattooed_

all over with monstrous superstitions, the case is very like the one

we have just been considering. When Sir James Stephen compares our

belief in the uniformity of nature, the congruity of the future with

the past, to a man rowing one way and looking another, and steering

his boat by keeping her stern in a line with an object behind him,

the operative link becomes harder to dissect out. It is subtler still

in Dr. Holmes's phrase, that stories in passing from mouth to mouth

make a great deal of lee-way in proportion to their headway; or in

Mr. Lowell's description of German sentences, that they have a way of

yawing and going stern-foremost and not minding the helm for several

minutes after it has been put down. And finally, it is a real puzzle

when the color pale-blue is said to have feminine and blood-red

masculine affinities. And if I hear a friend describe a certain family

as having _blotting-paper_ voices, the image, though immediately felt

to be apposite, baffles the utmost powers of analysis. The higher poets

all use abrupt epithets, which are alike intimate and remote, and, as

Emerson says, sweetly torment us with invitations to their inaccessible

homes.

In these latter instances we must suppose that there is an identical

portion in the similar objects, and that its brain-tract is

energetically operative, without, however, being sufficiently isolable

in its activity as to stand out _per se_, and form the condition of a

distinctly discriminated 'abstract idea.' We cannot even by careful

search see the bridge over which we passed from the heart of one

representation to that of the next. In some brains, however, this

mode of transition is extremely common. It would be one of the most

important of physiological discoveries could we assign the mechanical

or chemical difference which makes the thoughts of one brain cling

close to impartial redintegration, while those of another shoot about

in all the lawless revelry of similarity. Why, in these latter brains,

action should tend to focalize itself in small spots, while in the

others it fills patiently its broad bed, it seems impossible to guess.

Whatever the difference may be, it is what separates the man of genius

from the prosaic creature of habit and routine thinking. In Chapter

XXII we shall need to recur again to this point.

ASSOCIATION IN VOLUNTARY THOUGHT.

Hitherto we have assumed the process of suggestion of one object by

another to be spontaneous. The train of imagery wanders at its own

sweet will, now trudging in sober grooves of habit, now with a hop,

skip, and jump darting across the whole field of time and space.

This is revery, or musing; but great segments of the flux of our

ideas consist of something very different from this. They are guided

by a distinct purpose or conscious interest. As the Germans say, we

_nachdenken_, or think towards a certain end. It is now necessary to

examine what modification is made in the trains of our imagery by

the having of an end in view. The course of our ideas is then called

_voluntary_.

Physiologically considered, we must suppose that a purpose means

the persistent activity of certain rather definite brain-processes

throughout the whole course of thought. Our most usual cogitations are

not pure reveries, absolute driftings, but revolve about some central

interest or topic to which most of the images are relevant, and towards

which we return promptly after occasional digressions. This interest

is subserved by the persistently active brain-tracts we have supposed.

In the mixed associations which we have hitherto studied, the parts of

each object which form the pivots on which our thoughts successively

turn have their interest largely determined by their connection with

some _general interest_ which for the time has seized upon the mind.

If we call Z the brain-tract of general interest, then, if the object

_abc_ turns up, and _b_ has more associations with Z than have either

_a_ or _c, b_ will become the object's interesting, pivotal portion,

and will call up its own associates exclusively. For the energy of

_b_'s brain-tract will be augmented by Z's activity,--an activity

which, from lack of previous connection between Z and _a_ or _c_, does

not influence _a_ or _c_. If, for instance, I think of Paris whilst I

am _hungry_, I shall not improbably find that its _restaurants_ have

become the pivot of my thought, etc., etc.

But in the theoretic as well as in the practical life there are

interests of a more acute sort, taking the form of definite images

of some achievement, be it action or acquisition, which we desire to

effect. The train of ideas arising under the influence of such an

interest constitutes usually the thought of the _means_ by which the

end shall be attained. If the end by its simple presence does not

instantaneously suggest the means, the search for the latter becomes

an intellectual _problem_. The solution of problems is the most

characteristic and peculiar sort of voluntary thinking. Where the

end thought of is some outward deed or gain, the solution is largely

composed of the actual motor processes, walking, speaking, writing,

etc., which lead up to it. Where the end is in the first instance only

ideal, as in laying out a place of operations, the steps are purely

imaginary. In both of these cases the discovery of the means may form

a new sort of end, of an entirely peculiar nature, an end, namely,

which we intensely desire before we have attained it, but of the nature

of which, even whilst most strongly craving it, we have no distinct

imagination whatever. Such an end is a problem.

The same state of things occurs whenever we seek to recall something

forgotten, or to state the reason for a judgment which we have made

intuitively. The desire strains and presses in a direction which it

feels to be right but towards a point which it is unable to see. In

short, the _absence of an item_ is a determinant of our representations

quite as positive as its presence can ever be. The gap becomes no

mere void, but what is called an _aching_ void. If we try to explain

in terms of brain-action how a thought which only potentially

exists can yet be effective, we seem driven to believe that the

brain-tract thereof must actually be excited, but only in a minimal

and sub-conscious way. Try, for instance, to symbolize what goes on in

a man who is racking his brains to remember a thought which occurred

to him last week. The associates of the thought are there, many of

them at least, but they refuse to awaken the thought itself. We cannot

suppose that they do not irradiate _at all_ into its brain-tract,

because his mind quivers on the very edge of its recovery. Its actual

rhythm sounds in his ears; the words seem on the imminent point of

following, but fail. What it is that blocks the discharge and keeps the

brain-excitement here from passing beyond the nascent into the vivid

state cannot be guessed. But we see in the philosophy of desire and

pleasure, that such nascent excitements, spontaneously tending to a

crescendo, but inhibited or checked by other causes, may become potent

mental stimuli and determinants of desire. All questioning, wonder,

emotion of curiosity, must be referred to cerebral causes of some

such form as this. The great difference between the effort to recall

things forgotten and the search after the means to a given end, is that

the latter have not, whilst the former have, already formed a part

of our experience. If we first study _the mode of recalling a thing

forgotten_, we can take up with better understanding the voluntary

quest of the unknown.

The forgotten thing is felt by us as a gap in the midst of certain

other things. If it is a thought, we possess a dim idea of where we

were and what we were about when it occurred to us. We recollect the

general subject to which it relates. But all these details refuse to

shoot together into a solid whole, for the lack of the vivid traits

of this missing thought, the relation whereof to each detail forms

now the main interest of the latter. We keep running over the details

in our mind, dissatisfied, craving something more. From each detail

there radiate lines of association forming so many tentative guesses.

Many of these are immediately seen to be irrelevant, are therefore

void of interest, and lapse immediately from consciousness. Others are

associated with the other details present, and with the missing thought

as well. When _these_ surge up, we have a peculiar feeling that we are

'warm,' as the children say when they play hide and seek; and such

associates as these we clutch at and keep before the attention. Thus

we recollect successively that when we had the thought in question we

were at the dinner-table; then that our friend J. D. was there; then

that the subject talked about was so and so; finally, that the thought

came _à propos_ of a certain anecdote, and then that it had something

to do with a French quotation. Now all these added associations _arise

independently of the will_, by the spontaneous process we know so well.

_All that the will does is to emphasize and linger over those which

seem pertinent, and ignore the rest._ Through this hovering of the

attention in the neighborhood of the desired object, the accumulation

of associates becomes so great that the combined tensions of their

neural processes break through the bar, and the nervous wave pours

into the tract which has so long been awaiting its advent. And as the

expectant, sub-conscious itching there, bursts into the fulness of

vivid feeling, the mind finds an inexpressible relief.

The whole process can be rudely symbolized in a diagram. Call the

forgotten thing Z, the first facts with which we felt it was related,

_a, b,_ and _c_, and the details finally operative in calling it up,

_l, m,_ and _n_. Each circle will then stand for the brain-process

underlying the thought of the object denoted by the letter contained

within it. The activity in Z will at first be a mere tension; but as

the activities in _a, b,_ and _c_ little by little irradiate into _l,

m,_ and _n,_ and as _all_ these processes are somehow connected with

Z, their combined irradiations upon Z, represented by the centripetal

arrows, succeed in helping the tension there to overcome the

resistance, and in rousing Z also to full activity.

[Illustration: FIG. 44.]

The tension present from the first in Z, even though it keep below

the threshold of discharge, is probably to some degree co-operative

with _a, b, c_ in determining that _l, m, n_ shall awake. Without Z's

tension there might be a slower accumulation of objects connected with

it. But, as aforesaid, the objects come before us through the brain's

own laws, and the Ego of the thinker can only remain on hand, as it

were, to recognize their relative values and brood over some of them,

whilst others are let drop. As when we have lost a material object we

cannot recover it by a direct effort, but only through moving about

such neighborhoods wherein it is likely to lie, and trusting that it

will then strike our eye; so here, by not letting our attention leave

the neighborhood of what we seek, we trust that it will end by speaking

to us of its own accord.[485]

* * * * *

_Turn now to the case of finding the unknown means to a distinctly

conceived end._ The end here stands in the place of _a, b, c,_ in the

diagram. It is the starting-point of the irradiations of suggestion;

and here, as in that case, what the voluntary attention does is only

to dismiss some of the suggestions as irrelevant, and hold fast to

others which are felt to be more pertinent--let these be symbolized by

_l, m, n_. These latter at last accumulate sufficiently to discharge

all together into Z, the excitement of which process is, in the mental

sphere, equivalent to the solution of our problem. The only difference

between this case and the last, is that in this one there need be

no original sub-excitement in Z, co-operating from the very first.

When we seek a forgotten name, we must suppose the name's centre

to be in a state of active tension from the very outset, because of

that peculiar feeling of _recognition_ which we get at the moment of

recall. The plenitude of the thought seems here but a maximum degree

of something which our mind divined in advance. It instantaneously

fills a socket completely moulded to its shape; and it seems most

natural to ascribe the identity of quality in our feeling of the gaping

socket and our feeling of what comes to fill it, to the sameness of a

nerve-tract excited in different degrees. In the solving of a problem,

on the contrary, the recognition that we have found the means is much

less immediate. Here, what we are aware of in advance seems to be

its relations with the items we already know. It must bear a causal

relation, or it must be an effect, or it must contain an attribute

common to two items, or it must be a uniform concomitant, or what not.

We know, in short, a lot _about_ it, whilst as yet we have no knowledge

of _acquaintance_ with it (see p. 221), or in Mr. Hodgson's language,

"we know what we want to find beforehand, in a certain sense, in its

second intention, and do not know it, in another sense, in its first

intention."[486] Our intuition that one of the ideas which turn up is,

at last, our _quæsitum_, is due to our recognition that its relations

are identical with those we had in mind, and this may be a rather slow

act of judgment. In fact, every one knows that an object may be for

some time present to his mind before its relations to other matters are

perceived. To quote Hodgson again:

"The mode of operation is common to voluntary memory and reason....

But reasoning adds to memory the function of comparing or judging the

images which arise.... Memory aims at filling the gap with an image

which has at some particular time filled it before, reasoning with one

which bears certain time-and space-relations to the images before and

after"--

or, to use perhaps clearer language, one which stands in determinate

logical relations to those data round about the gap which filled our

mind at the start. This feeling of the blank form of relationship

before we get the material quality of the thing related will surprise

no one who has read Chapter IX.

From the guessing of newspaper enigmas to the plotting of the policy of

an empire there is no other process than this. We trust to the laws of

cerebral nature to present us spontaneously with the appropriate idea:

"Our only command over it is by the effort we make to keep the painful

unfilled gap in consciousness.[487]... Two circumstances are important

to notice: the first is, that volition has no power of calling up

images, but only of rejecting and selecting from those offered by

spontaneous redintegration.[488] But the rapidity with which this

selection is made, owing to the familiarity of the ways in which

spontaneous redintegration runs, gives the process of reasoning the

appearance of evoking images that are foreseen to be conformable to

the purpose. There is no seeing them before they are offered; there

is no summoning them before they are seen. The other circumstance is,

that every kind of reasoning is nothing, in its simplest form, but

attention."[489]

It is foreign to our purpose here to enter into any detailed analysis

of the different classes of mental pursuit. In a scientific research

we get perhaps as rich an example as can be found. The inquirer starts

with a fact of which he seeks the reason, or with an hypothesis of

which he seeks the proof. In either case he keeps turning the matter

incessantly in his mind until, by the arousal of associate upon

associate, some habitual, some similar, one arises which he recognizes

to suit his need. This, however, may take years. No rules can be given

by which the investigator may proceed straight to his result; but both

here and in the case of reminiscence the accumulation of helps in the

way of associations may advance more rapidly by the use of certain

routine methods. In striving to recall a thought, for example, we may

of set purpose run through the successive classes of circumstance with

which it may possibly have been connected, trusting that when the

right member of the class has turned up it will help the thought's

revival. Thus we may run through all the _places_ in which we may have

had it. We may run through the _persons_ whom we remember to have

conversed with, or we may call up successively all the _books_ we have

lately been reading. If we are trying to remember a person we may run

through a list of streets or of professions. Some item out of the lists

thus methodically gone over will very likely be associated with the

fact we are in need of, and may suggest it or help to do so. And yet

the item might never have arisen without such systematic procedure. In

scientific research this accumulation of associates has been methodized

by Mill under the title of 'The Four Methods of Experimental Inquiry.'

By the 'method of agreement,' by that of 'difference,' by those of

'residues' and 'concomitant variations'(which cannot here be more

nearly defined), we make certain lists of cases; and by ruminating

these lists in our minds the cause we seek will be more likely to

emerge. But the final stroke of discovery is only prepared, not

effected, by them. The brain-tracts must, of their own accord, shoot

the right way at last, or we shall still grope in darkness. That in

some brains the tracts _do_ shoot the right way much oftener than in

others, and that we cannot tell why,--these are ultimate facts to which

we must never close our eyes. Even in forming our lists of instances

according to Mill's methods, we are at the mercy of the spontaneous

workings of Similarity in our brain. How are a number of facts,

resembling the one whose cause we seek, to be brought together in a

list unless the one will rapidly suggest the other through association

by similarity?

SIMILARITY NO ELEMENTARY LAW.

Such is the analysis I propose, first of the three main types of

spontaneous association, and then of voluntary association. It will

be observed that the _object called up may bear any logical relation

whatever to the one which suggested it_. The law requires only that

one condition should be fulfilled. The fading object must be due to

a brain-process some of whose elements awaken through habit some

of the elements of the brain-process of the object which comes to

view. This awakening is the operative machinery, the causal agency,

throughout, quite as much so in the kind of association I have called

by the name of Similarity, as in any other sort. The similarity between

the objects, or between the thoughts (if similarity there be between

these latter), has no causal agency in carrying us from one to the

other. It is but a result--the effect of the usual causal agent when

this happens to work in a certain particular and assignable way. But

ordinary writers talk as if the similarity of the objects were itself

an agent, co-ordinate with habit, and independent of it, and like it

able to push objects before the mind. This is quite unintelligible. The

similarity of two things does not exist till both things are there--it

is meaningless to talk of it as an _agent of production_ of anything,

whether in the physical or the psychical realms.[490] It is a relation

which the mind perceives after the fact, just as it may perceive the

relations of superiority, of distance, of causality, of container and

content, of substance and accident, or of contrast, between an object

and some second object which the associative machinery calls up.[491]

There are, nevertheless, able writers who not only insist on preserving

association by similarity as a distinct elementary law, but who make

it the most elementary law, and seek to derive contiguous association

from it. Their reasoning is as follows: When the present impression

A awakens the idea _b_ of its past contiguous associate B, how can

this occur except through first reviving an image _a_ of its own past

occurrence. _This_ is the term directly connected with _b_; so that

the process instead of being simply A--_b_ is A--_a--b_. Now A and

_a_ are similars; therefore no association by contiguity can occur

except through a previous association by similarity. The most important

supposition here made is that every impression on entering the mind

must needs awaken an image of its past self, in the light of which it

is 'apperceived' or understood, and through the intermediation of which

it enters into relation with the mind's other objects. This assumption

is almost universally made; and yet it is hard to find any good reason

for it. It first came before us when we were reviewing the facts of

aphasia and mental blindness (see p. 50 ff.). But we then saw no need

of optical and auditory images to interpret optical and auditory

sensations by. On the contrary, we agreed that auditory sensations were

understood by us only so far as they awakened _non_-auditory images,

and optical sensations only so far as they awakened _non_-optical

images. In the chapters on Memory, on Reasoning, and on Perception the

same assumption will meet us again, and again will have to be rejected

as groundless. The sensational process A and the ideational process _a_

probably occupy essentially the same tracts. When the outer stimulus

comes and those tracts vibrate with the sensation A, they discharge

as directly into the paths which lead to B as when there is no outer

stimulus and they only vibrate with the idea _a_. To say that the

process A can only reach these paths by the help of the weaker process

_a_ is like saying that we need a candle to see the sun by. A replaces

_a_, does all that _a_ does and more; and there is no intelligible

meaning, to my mind, in saying that the weaker process coexists with

the stronger. I therefore consider that these writers are altogether

wrong. The only plausible proof they give of the coexistence of _a_

with A is when A gives us a _sense of familiarity_ but fails to awaken

any distinct thought of past contiguous associates. In a later chapter

I shall consider this case. Here I content myself with saying that it

does not seem conclusive as to the point at issue; and that I still

believe association of coexistent or sequent impressions to be the one

_elementary_ law.

* * * * *

CONTRAST _has also been held to be an independent agent in

association._ But the reproduction of an object contrasting with one

already in the mind is easily explained on our principles. Recent

writers, in fact, all reduce it either to similarity or contiguity.

Contrast always presupposes generic similarity; it is only the

_extremes of a class_ which are contrasted, black and white, not

black and sour, or white and prickly. A machinery which reproduces

a similar at all, may reproduce the _opposite_ similar, as well as

any intermediate term. Moreover, the greater number of contrasts are

habitually coupled in speech, young and old, life and death, rich and

poor, etc., and are, as Dr. Bain says, in everybody's memory.[492]

* * * * *

I trust that the student will now feel that the way to a deeper

understanding of the order of our ideas lies in the direction of

cerebral physiology. The _elementary_ process of revival can be nothing

but the law of habit. Truly the day is distant when physiologists

shall actually trace from cell-group to cell-group the irradiations

which we have hypothetically invoked. Probably it will never arrive.

The schematism we have used is, moreover, taken immediately from the

analysis of objects into their elementary parts, and only extended by

analogy to the brain. And yet it is only as incorporated in the brain

that such a schematism can represent anything _causal_. This is, to my

mind, the conclusive reason for saying that the order of _presentation

of the mind's materials_ is due to cerebral physiology alone.

The law of accidental prepotency of certain processes over others

falls also within the sphere of cerebral probabilities. Granting such

instability as the brain-tissue requires, certain points must always

discharge more quickly and strongly than others; and this prepotency

would shift its place from moment to moment by accidental causes,

giving us a perfect mechanical diagram of the capricious play of

similar association in the most gifted mind. The study of dreams

confirms this view. The usual abundance of paths of irradiation seems,

in the dormant brain, reduced. A few only are pervious, and the most

fantastic sequences occur because the currents run--'like sparks in

burnt-up paper'--wherever the nutrition of the moment creates an

opening, but nowhere else.

* * * * *

The _effects of interested attention and volition_ remain. These

activities seem to hold fast to certain elements, and by emphasizing

them and dwelling on them, to make their associates the only ones which

are evoked. _This_ is the point at which an anti-mechanical psychology

must, if anywhere, make it stand in dealing with association.

Everything else is pretty certainly due to cerebral laws. My own

opinion on the question of active attention and spiritual spontaneity

is expressed elsewhere. But even though there be a mental spontaneity,

it can certainly not create ideas or summon them _ex abrupto_. Its

power is limited to _selecting_ amongst those which the associative

machinery has already introduced or tends to introduce. If it can

emphasize, reinforce, or protract for a second either one of these, it

can do all that the most eager advocate of free will need demand; for

it then decides the direction of the next associations by making them

hinge upon the emphasized term; and determining in this wise the course

of the man's thinking, it also determines his acts.

THE HISTORY OF OPINION CONCERNING ASSOCIATION

may be briefly glanced at ere we end the chapter.[493] Aristotle seems

to have caught both the facts and the principle of explanation; but

he did not expand his views, and it was not till the time of Hobbes

that the matter was again touched on in a definite way. Hobbes first

formulated the problem of the succession of our thoughts. He writes in

Leviathan, chapter iii, as follows:

"By consequence, or train of thoughts, I understand that succession

of one thought to another which is called, to distinguish it from

discourse in words, _mental discourse_. When a man thinketh on

anything whatsoever, his next thought after is not altogether so

casual as it seems to be. Not every thought to every thought succeeds

indifferently. But as we have no imagination, whereof we have not

formerly had sense, in whole or in parts; so we have no transition

from one imagination to another, whereof we never had the like before

in our senses. The reason whereof is this. All fancies are motions

within us, relics of those made in the sense: and those motions that

immediately succeeded one another in the sense continue also together

after sense: insomuch as the former coming again to take place, and

be predominant, the latter followeth, by coherence of the matter

moved, in such manner, as water upon a plane table is drawn which way

any one part of it is guided by the finger. But because in sense,

to one and the same thing perceived, sometimes one thing, sometimes

another succeedeth, it comes to pass in time that, in the imagining of

anything, there is no certainty what we shall imagine next; only this

is certain, it shall be something that succeeded the same before, at

one time or another. This train of thoughts, or mental discourse, is

of two sorts. The first is _unguided, without design,_ and inconstant;

wherein there is no passionate thought, to govern and direct those

that follow, to itself, as the end and scope of some desire, or other

passion.... The second is more constant; as being _regulated_ by

some desire and design. For the impression made by such things as we

desire, or fear, is strong and permanent, or, if it cease for a time,

of quick return: so strong is it, sometimes, as to hinder and break

our sleep. From desire ariseth the thought of some means we have

seen produce the like of that which we aim at; and from the thought

of that, the thought of means to that mean; and so continually, till

we come to some beginning within our own power. And because the end,

by the greatness of the impression, comes often to mind, in case our

thoughts begin to wander, they are quickly again reduced into the way:

which observed by one of the seven wise men, made him give men this

precept, which is now worn out, _Respite finem_; that is to say, in

all your actions, look often upon what you would have, as the thing

that directs all your thoughts in the way to attain it.

"The train of regulated thoughts is of two kinds; one, when of an

effect imagined we seek the causes, or means that produce it: and this

is common to man and beast. The other is, when imagining anything

whatsoever, we seek all the possible effects that can by it be

produced; that is to say, we imagine what we can do with it, when we

have it. Of which I have not at any time seen any sign, but in man

only; for this is a curiosity hardly incident to the nature of any

living creature that has no other passion but sensual, such as are

hunger, thirst, lust, and anger. In sum, the discourse of the mind,

when it is governed by design, is nothing but _seeking_ or the faculty

of invention, which the Latins called _sagacitas_, and _sollertia_; a

hunting out of the causes, of some effect, present or past; or of the

effects, of some present or past cause."

The most important passage after this of Hobbes is Hume's:

"As all simple ideas may be separated by the imagination, and may

be united again in what form it pleases, nothing would be more

unaccountable than the operations of that faculty, were it not guided

by some universal principles, which render it, in some measure,

uniform with itself in all times and places. Were ideas entirely loose

and unconnected, chance alone would join them; and 'tis impossible the

same simple ideas should fall regularly into complex ones (as they

commonly do) without some bond of union among them, some associating

quality, by which one idea naturally introduces another. This uniting

principle among ideas is not to be considered as an inseparable

connection; for that has been already excluded from the imagination.

Nor yet are we to conclude that without it the mind cannot join two

ideas; for nothing is more free than that faculty: but we are only to

regard it as a gentle force, which commonly prevails, and is the cause

why, among other things, languages so nearly correspond to each other;

nature in a manner pointing to every one those simple ideas which are

most proper to be united in a complex one. The qualities from which

this association arises, and by which the mind is after this manner

conveyed from one idea to another, are three, viz., RESEMBLANCE,

CONTIGUITY in time or place, and CAUSE and EFFECT.

"I believe it will not be very necessary to prove that these qualities

produce an association among ideas, and upon the appearance of one

idea naturally introduce another. 'Tis plain that in the course of our

thinking, and in the constant revolution of our ideas, our imagination

runs easily from one idea to any other that _resembles_ it, and that

this quality alone is to the fancy a sufficient bond and association.

'Tis likewise evident, that as the senses, in changing their objects,

are necessitated to change them regularly, and take them as they

lie _contiguous_ to each other, the imagination must by long custom

acquire the same method of thinking, and run along the parts of space

and time in conceiving its objects. As to the connection that is

made by the relation of _cause and effect_, we shall have occasion

afterwards to examine it to the bottom, and therefore shall not at

present insist upon it. 'Tis sufficient to observe that there is no

relation which produces a stronger connection in the fancy, and makes

one idea more readily recall another, than the relation of cause and

effect betwixt their objects.... These are therefore the principles

of union or cohesion among our simple ideas, and in the imagination

supply the place of that inseparable connection by which they are

united in our memory. Here is a kind of ATTRACTION, which in the

mental world will be found to have as extraordinary effects as in

the natural, and to show itself in as many and as various forms. Its

effects are everywhere conspicuous; but as to its causes, they are

mostly unknown, and must be resolved into _original_ qualities of

human nature, which I pretend not to explain."[494]

Hume did not, however, any more than Hobbes, follow out the effects of

which he speaks, and the task of popularizing the notion of association

and making an effective school based on association of ideas alone was

reserved for Hartley[495] and James Mill.[496] These authors traced

minutely the presence of association in all the cardinal notions and

operations of the mind. The several 'faculties' of the Mind were

dispossessed; the one principle of association between ideas did all

their work. As Priestley says:

"Nothing is requisite to make any man whatever he is, but a sentient

principle with this single law.... Not only all our intellectual

pleasures and pains but all the phenomena of memory, imagination,

volition, reasoning and every other mental affection and operation,

are but different modes or cases of the association of ideas."[497]

An eminent French psychologist, M. Ribot, repeats Hume's comparison of

the law of association with that of gravitation, and goes on to say:

"It is remarkable that this discovery was made so late. Nothing is

simpler, apparently, than to notice that this law of association is

the truly fundamental, irreducible phenomenon of our mental life;

that it is at the bottom of all our acts; that it permits of no

exception; that neither dream, revery, mystic ecstasy, nor the most

abstract reasoning can exist without it; that its suppression would be

equivalent to that of thought itself. Nevertheless no ancient author

understood it, for one cannot seriously maintain that a few scattered

lines in Aristotle and the Stoics constitute a theory and clear view

of the subject. It is to Hobbes, Hume, and Hartley that we must

attribute the origin of these studies on the connection of our ideas.

The discovery of the ultimate law of our psychologic acts has this,

then, in common with many other discoveries: it came late and seems so

simple that it may justly astonish us.

"Perhaps it is not superfluous to ask in what this manner of

explanation is superior to the current theory of Faculties.[498] The

most extended usage consists, as we know, in dividing intellectual

phenomena into classes, in separating those which differ, in grouping

together those of the same nature and in giving to these a common name

and in attributing them to the same cause; it is thus that we have

come to distinguish those diverse aspects of intelligence which are

called judgment, reasoning, abstraction, perception, etc. This method

is precisely the one followed in Physics, where the words caloric,

electricity, gravity, designate the unknown causes of certain groups

of phenomena. If one thus never forgets that the diverse faculties are

only the unknown causes of known phenomena, that they are simply a

convenient means of classifying the facts and speaking of them, if one

does not fall into the common fault of making out of them substantial

entities, creations which now agree, now disagree, so forming in the

intelligence a little republic; then, we can see nothing reprehensible

in this distribution into faculties, conformable as it is to the

rules of a sound method and of a good natural classification. In what

then is Mr. Bain's procedure superior to the method of the faculties?

It is that the latter is simply a _classification_ while his is an

_explanation_. Between the psychology which traces intellectual facts

back to certain faculties, and that which reduces them to the single

law of association, there is, according to our way of thinking, the

same difference that we find in Physics between those who attribute

its phenomena to five or six causes, and those who derive gravity

caloric, light, etc., from motion. The system of the faculties

explains nothing because each one of them is only a _flatus vocis_

which is of value merely through the phenomena which it contains, and

signifies nothing more than these phenomena. The new theory, on the

contrary, shows that the different processes of intelligence are only

diverse cases of a single law; that imagination, deduction, induction,

perception, etc., are but so many determinate ways in which ideas

may combine with each other; and that the differences of faculties

are only differences of association. It _explains_ all intellectual

facts, certainly not after the manner of Metaphysics which demands

the ultimate and absolute reason of things; but after the manner of

Physics which seeks only their secondary and immediate cause."[499]

The inexperienced reader may be glad of a brief indication of the

manner in which all the different mental operations may be conceived to

consist of images of sensation associated together.

_Memory_ is the association of a present image with others known to

belong to the past. _Expectation_ the same, with future substituted for

past. _Fancy_, the association of images without temporal order.

_Belief_ in anything _not_ present to sense is the very lively,

strong, and steadfast association of the image of that thing with some

present sensation, so that as long as the sensation persists the image

cannot be excluded from the mind.

_Judgment_ is 'transferring the idea of _truth_ by association from one

proposition to another that resembles it.'[500]

_Reasoning_ is the perception that "whatever has any mark has that

which it is a mark of"; in the concrete case the mark or middle term

being always _associated_ with each of the other terms and so serving

as a link by which they are themselves indirectly associated together.

This same kind of transfer of a sensible experience associated

with another to a third also associated with that other, serves to

explain emotional facts. When we are pleased or hurt we express it,

and the expression associates itself with the feeling. Hearing the

same expression from another revives the associated feeling, and we

_sympathize_, i.e. grieve or are glad with him.

The other social affections, _Benevolence, Conscientiousness,

Ambition,_ etc., arise in like manner by the transfer of the bodily

pleasure experienced as a reward for social service, and hence

associated with it, to the act of service itself, the link of reward

being dropped out. Just so _Avarice_ when the miser transfers the

bodily pleasures associated with the spending of money to the money

itself, dropping the link of spending.

_Fear_ is a transfer of the bodily hurt associated by experience

with the thing feared, to the thought of the thing, with the precise

features of the hurt left out. Thus we fear a dog without distinctly

imagining his bite.

_Love_ is the association of the agreeableness of certain sensible

experiences with the idea of the object capable of affording them.

The experiences themselves may cease to be distinctly imagined after

the notion of their pleasure has been transferred to the object,

constituting our love therefor.

_Volition_ is the association of ideas of muscular motion with the

ideas of those pleasures which the motion produces. The motion at first

occurs automatically and results in a pleasure unforeseen. The latter

becomes so associated with the motion that whenever we think of it the

idea of the motion arises; and the idea of the motion when vivid causes

the motion to occur. This is an act of will.

Nothing is easier than for a philosopher of this school to explain from

experience such a notion as that of infinitude.

"He sees in it an ordinary manifestation of one of the laws of the

association of ideas,--the law that the idea of a thing irresistibly

suggests the idea of any other thing which has been often experienced

in close conjunction with it, and not otherwise. As we have never

had experience of any point of space without other points beyond

it, nor of any point of time without others following it, the law

of indissoluble association makes it impossible for us to think of

any point of space or time, however distant, without having the idea

irresistibly realized, in imagination, of other points still more

remote. And thus the supposed original and inherent property of these

two ideas is completely explained and accounted for by the law of

association; and we are enabled to see that if Space or Time were

really susceptible of termination, we should be just as unable as we

now are to conceive the idea."[501]

These examples of the Associationist Psychology are with the exception

of the last, very crudely expressed, but they suffice for our temporary

need. Hartley and James Mill[502] improved upon Hume so far as to

employ but a single principle of association, that of contiguity or

habit. Hartley ignores resemblance, James Mill expressly repudiates it

in a passage which is assuredly one of the curiosities of literature:

"I believe it will be found that we are accustomed to see like things

together. When we see a tree, we generally see more trees than one;

a sheep, more sheep than one; a man, more men than one. From this

observation, I think, we may refer resemblance to the law of frequency

[i.e., contiguity], of which it seems to form only a particular case."

Mr. Herbert Spencer has still more recently tried to construct a

Psychology which ignores Association by Similarity,[503] and in

a chapter, which also is a curiosity, he tries to explain the

association of two ideas by a conscious reference of the first to the

point of time when its sensation was experienced, which point of time

is no sooner thought of than its content, namely, the second idea,

arises. Messrs. Bain and Mill, however, and the immense majority of

contemporary psychologists retain both Resemblance and Contiguity as

irreducible principles of Association.

Professor Bain's exposition of association is by common consent

looked upon as the best expression of the English school. Perception

of agreement and difference, retentiveness, and the two sorts of

association, contiguity and similarity, are by him regarded as

constituting all that is meant by intellect proper. His pages are

painstaking and instructive from a descriptive point of view; though,

after my own attempt to deal with the subject causally, I can hardly

award to them any profound _explanatory_ value. Association by

Similarity, too much neglected by the British school before Bain,

receives from him the most generous exemplification. As an instructive

passage, the following, out of many equally good, may be chosen to

quote:

"We may have similarity in form with diversity of use, and similarity

of use with diversity of form. A rope suggests other ropes and

cords, if we look to the appearance; but looking to the _use_, it

may suggest an iron cable, a wooden prop, an iron girding, a leather

band, or bevelled gear. In spite of diversity of appearance, the

suggestion turns on what answers a common end. If we are very much

attracted by sensible appearances, there will be the more difficulty

in recalling things that agree only in the use; if, on the other

hand, we are profoundly sensitive to the one point of practical

efficiency as a tool, the peculiarities not essential to this will

be little noticed, and we shall be ever ready to revive past objects

corresponding in use to some one present, although diverse in all

other circumstances. We become oblivious to the difference between a

horse, a steam-engine, and a waterfall, when our minds are engrossed

with the one circumstance of moving power. The diversity in these

had no doubt for a long time the effect of keeping back their first

identification; and to obtuse intellects, this identification might

have been for ever impossible. A strong concentration of mind upon the

single peculiarity of mechanical force, and a degree of indifference

to the general aspect of the things themselves, must conspire with

the intellectual energy of resuscitation by similars, in order to

summon together in the view three structures so different. We can

see, by an instance like this, how new adaptations of existing

machinery might arise in the mind of a mechanical inventor. When it

first occurred to a reflecting mind that moving water had a property

identical with human or brute force, namely, the property of setting

other masses in motion, overcoming inertia and resistance,--when the

sight of the stream suggested through this point of likeness the

power of the animal,--a new addition was made to the class of prime

movers, and when circumstances permitted, this power could become a

substitute for the others. It may seem to the modern understanding,

familiar with water-wheels and drifting rafts, that the similarity

here was an extremely obvious one. But if we put ourselves back into

an early state of mind, when running water affected the mind by its

brilliancy, its roar, and irregular devastation, we may easily suppose

that to identify this with animal muscular energy was by no means an

obvious effect. Doubtless when a mind arose, insensible by natural

constitution to the superficial aspects of things, and having withal

a great stretch of identifying intellect, such a comparison would

then be possible. We may pursue the same example one stage further,

and come to the discovery of steam power, or the identification of

expanding vapor with the previously known sources of mechanical

force. To the common eye, for ages, vapor presented itself as clouds

in the sky; or as a hissing noise at the spout of a kettle, with the

formation of a foggy curling cloud at a few inches' distance. The

forcing up of the lid of a kettle may also have been occasionally

observed. But how long was it ere any one was struck with the

parallelism of this appearance with a blast of wind, a rush of water,

or an exertion of animal muscle? The discordance was too great to be

broken through by such a faint and limited amount of likeness. In one

mind, however, the identification did take place, and was followed

out into its consequences. The likeness had occurred to other minds

previously, but not with the same results. Such minds must have been

in some way or other distinguished above the millions of mankind; and

we are now endeavoring to give the explanation of their superiority.

The intellectual character of Watt contained all the elements

preparatory to a great stroke of similarity in such a case;--a high

susceptibility, both by nature and by education, to the mechanical

properties of bodies; ample previous knowledge or familiarity; and

indifference to the superficial and sensational effects of things.

It is not only possible, however, but exceedingly probable, that

many men possessed all these accomplishments; they are of a kind not

transcending common abilities. They would in some degree attach to a

mechanical education almost as a matter of course. That the discovery

was not sooner made supposes that something farther, and not of common

occurrence, was necessary; and this additional endowment appears to be

the identifying power of Similarity in general; the tendency to detect

likeness in the midst of disparity and disguise. This supposition

accounts for the fact, and is consistent with the known intellectual

character of the inventor of the steam-engine."[504]

Dr. Hodgson's account of association is by all odds the best yet

propounded in English.[505] All these writers hold more or less

explicitly to the notion of atomistic 'ideas' which recur. In Germany,

the same mythological supposition has been more radically grasped,

and carried out to a still more logical, if more repulsive, extreme,

by Herbart[506] and his followers, who until recently may be said to

have reigned almost supreme in their native country.[507] For Herbart

each idea is a permanently existing entity, the entrance whereof into

consciousness is but an accidental determination of its being. So far

as it succeeds in occupying the theatre of consciousness, it crowds

out another idea previously there. This act of inhibition gives it,

however, a sort of hold on the other representation which on all later

occasions facilitates its following the other into the mind. The

ingenuity with which most special cases of association are formulated

in this mechanical language of struggle and inhibition, is great, and

surpasses in analytic thoroughness anything that has been done by the

British school. This, however, is a doubtful merit, in a case where

the elements dealt with are artificial; and I must confess that to my

mind there is something almost hideous in the glib Herbartian jargon

about _Vorstellungsmassen_ and their _Hemmungen_ and _Hemmungssummen_,

and _sinken_ and _erheben_ and _schweben_, and _Verschmelzungen_

and _Complexionen_. Herr Lipps, the most recent systematic German

Psychologist, has, I regret to say, carried out the theory of ideas

in a way which the great originality, learning, and acuteness he

shows make only the more regrettable.[508] Such elaborately artificial

constructions are, it seems to me, only a burden and a hindrance, not a

help, to our science.[509]

In French, M. Rabier in his chapter on Association,[510] handles the

subject more vigorously and acutely than any one. His treatment of it,

though short, seems to me for general soundness to rank second only to

Hodgson's.

In the last chapter we already invoked association to account for

the effects of use in improving discrimination. In later chapters

we shall see abundant proof of the immense part which it plays in

other processes, and shall then readily admit that few principles of

analysis, in any science, have proved more fertile than this one,

however vaguely formulated it often may have been. Our own attempt to

formulate it more definitely, and to escape the usual confusion between

causal agencies and relations merely known, must not blind us to the

immense services of those by whom the confusion was unfelt. From this

practical point of view it would be a true _ignoratio elenchi_ to

flatter one's self that one has dealt a heavy blow at the psychology of

association, when one has exploded the theory of atomistic ideas, or

shown that contiguity and similarity between ideas can only be there

after association is done.[511] The whole body of the associationist

psychology remains standing after you have translated 'ideas' into

'objects,' on the one hand, and 'brain-processes' on the other; and the

analysis of faculties and operations is as conclusive in these terms as

in those traditionally used.

FOOTNOTES:

[463] The theory propounded in this chapter, and a good many pages of

the text, were originally published in the Popular Science Monthly for

March, 1880.

[464] Compare Renouvier's criticism of associationism in his Essais de

Critique générale, Logique, ii, p. 493 foll.

[465] Unless the name belong to a rapidly uttered sentence, when no

substantive image may have time to arise.

[466] In his observations he says that time was lost in mentally taking

in the word which was the cue, "owing to the quiet unobtrusive way in

which I found it necessary to bring it into view, so as not to distract

the thoughts. Moreover, a substantive standing by itself is usually the

equivalent of too abstract an idea for us to conceive properly without

delay. Thus it is very difficult to get a quick conception of the word

'carriage,' because there are so many different kinds--two-wheeled,

four-wheeled, open and closed, and in so many different possible

positions, that the mind possibly hesitates amidst an obscure sense of

many alternations that cannot blend together. But limit the idea to say

a landau, and the mental association declares itself more quickly."

(Inquiries, etc., p. 190.)

[467] Physiol. Psych., ii, 280 fol.

[468] For interesting remarks on the sorts of things associated, in

these experiments, with the prompting word, see Galton, _op. cit._ pp.

185-203, and Trautscholdt in Wundt's Psychologische Studien, i, 213.

[469] Mind, xi, 64-5.