ASSOCIATION.
=The Order of our Ideas.=--After discrimination, association! It is
obvious that all advance in knowledge must consist of both operations;
for in the course of our education, 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, between the thoughts which thus
appear to sprout one out of the other, _principles of connection_
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 small
number of _types_, like those which some authors call the 'categories'
of the understanding. According as we followed one category or another
we should sweep, from any object with our thought, in this way or in
that, to others. 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 categories is that they are all
thinkable relations, and that the mind proceeds from one object to
another by some intelligible path.
=Is it determined by any laws?= But as a matter of fact, What determines
the particular path? Why do we at a given time and place proceed to
think of _b_ if we have just thought of _a_, and at another time and
place why do we think, not of _b_, but of _c_? Why do we spend years
straining after a certain scientific or practical problem, but all in
vain--our thought unable 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?
The truth must be admitted that thought works under strange conditions.
Pure '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
opinions constitute a less bulky part of his mental furniture than his
clarified beliefs? And yet, the _mode of genesis_ of the worthy and the
worthless in our thinking seems the same.
=The laws are cerebral laws.= _There seem to be mechanical conditions on
which thought depends, and which_, to say the least, _determine the
order in which, the objects for her comparisons and selections are
presented_. 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 prepossessions, 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 the sequence of our
thoughts, and in so doing planted himself squarely upon the properly
_causal_ aspect of the problem, and sought to treat both rational and
irrational associations from a single point of view. How does a man
come, after having the thought of A, to have the thought 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 essential respects, on the right track, and I
propose simply to revise his conclusions by the aid of distinctions
which he did not make.
=Objects are associated, not ideas.= We shall avoid confusion if we
consistently speak as if _association_, so far as the word stands for an
_effect, were between_ THINGS THOUGHT OF--_as if it were_ THINGS, _not
ideas, which are associated in the mind_. We shall 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.
=The Elementary Principle.=--I shall now try to show 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 any 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.
My thesis, stated thus briefly, will soon become more clear; and at the
same time certain disturbing factors, which coöperate 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 re-occurring, tends to
propagate its excitement into the other._
But, as a matter of fact, every elementary process has unavoidably found
itself at different times excited in conjunction with _many_ other
processes. Which of these others it shall awaken now becomes a problem.
Shall _b_ or _c_ be aroused next by the present _a_? To answer this, we
must make a further postulate, based 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 (see p. 128). 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.
=Spontaneous Trains of Thought.=--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. 168 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.
=Total Recall.=--The ideal working of the law of compound association, as
Prof. Bain calls it, 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. 57 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.
[Illustration: FIG. 57.]
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.
Let us call this process _impartial redintegration_, or, still better,
_total recall_. 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--'"
=Partial Recall.=--This case helps us to understand why it is that the
ordinary spontaneous flow of our ideas does not follow the law of total
recall. _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, "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 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_, or, if we like better,
_partial recall_.
=Which Associates come up, in Partial Recall?=--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 a certain book has most frequently awakened in me thoughts
of the opinions therein propounded. The idea of suicide has never been
connected with the volume. But a moment since, as my eye fell upon it,
suicide was the thought that flashed into my mind. Why? Because but
yesterday I received a letter informing me that the author's recent
death 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.[36]
_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, used, and picked them; but the
rarer and remoter associations arise more promptly because they were so
much more intense.
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 inability
to keep up trains of joyous imagery when we are depressed in spirits.
Storm, darkness, war, images of disease, poverty, perishing, and dread
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 woful
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 object will form an
important ingredient in the object which comes next. 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 263. 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? Any reader's experience will
easily furnish similar instances. So we must admit 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.
=Focalized Recall, or 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 the interested attention refines itself still
further and accentuates a portion of the passing object, 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 object 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_.'
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 summon up that of
another shade of blue, etc., unless indeed we have in mind some general
purpose of nomenclature or comparison which requires a review of several
blue tints.
Now 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.
[Illustration: FIG. 58.]
The gradual passage from total to focalized, through what we have called
ordinary partial, recall may be symbolized by diagrams. Fig. 58 is
total, Fig. 59 is partial, and Fig. 60 focalized, recall. _A_ in each is
the passing, _B_ the coming, thought. In 'total recall,' all parts of
_A_ are equally operative in calling up _B_. In 'partial recall,' most
parts of _A_ are inert. The part _M_ alone breaks out and awakens _B_.
In similar association or 'focalized recall,' the 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.[37]
[Illustration: FIG. 59.]
[Illustration: FIG. 60.]
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 consciousness itself.
But into this we cannot enter now.
=Voluntary Trains of 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; and 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_ and _Z_ and _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.
=Problems.=--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 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 a _problem_; and the discovery of the
means forms 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 (compare pp. 241-2).
The same thing 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 (see p. 165). Now the only 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.
=Their Solution.=--The forgotten thing is felt by us as a gap in the midst
of certain other things. We possess a dim idea of where we were and what
we were about when it last occurred to us. We recollect the general
subject to which it pertains. But all these details refuse to shoot
together into a solid whole, for the lack of the missing thing, so we
keep running over them 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 last were
considering the matter 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 associates _arise independently of the will_, by the
spontaneous processes 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, so to speak,
bursts into the fulness of vivid feeling, the mind finds an
inexpressible relief.
[Illustration: FIG. 61.]
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
principally concerned in the thought of the fact lettered 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 rousing _Z_ also to full activity.
_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 and the previous case is that in this one there need be no
original sub-excitement in _Z_, coöperating from the very first. In the
solving of a problem, all that we are aware of in advance seems to be
its _relations_. It must be a cause, or it must be an effect, or it must
contain an attribute, or it must be a means, or what not. We know, in
short, a lot _about_ it, whilst as yet we have no _acquaintance_ with
it. Our perception that one of the objects 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. Every one knows that an object may be for some time present
to his mind before its relations to other matters are perceived. Just so
the relations may be there before the object is.
From the guessing of newspaper enigmas to the plotting of the policy of
an empire there is no other process than this. We must trust to the laws
of cerebral nature to present us spontaneously with the appropriate
idea, but we must know it for the right one when it comes.
It is foreign to my 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 one will rapidly suggest another
through association by similarity?
=Similarity no Elementary Law.=--Such is the analysis I propose, first of
the three main types of spontaneous, and then of voluntary, trains of
thought. 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 causal agency in the kind of
association called Similarity, as in any other sort. The similarity
_itself_ between the objects 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 way. Ordinary writers talk
as if the similarity of the objects were itself an agent, coördinate
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. 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.
=Conclusion.=--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 are due to the
unknown conditions by which in some brains action tends to focalize
itself in small spots, while in others it fills patiently its broad bed.
What these differing conditions are, it seems impossible to guess.
Whatever they are, they are what separate the man of genius from the
prosaic creature of habit and routine thinking. In the chapter on
Reasoning we shall need to recur again to this point. 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. A 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 its 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 (see p. 237). 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 introduces. If it can emphasize, reinforce, or
protract for half 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.