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.* . . . 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. 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."

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

* Ibid. p. 394.

+ All association is called redintegration by Hodgson.

Ibid. p. 400. Compare Bain, Emotions and Will, p. 377. "The out. goings of the mind are necessarily random; the end alone is the thing that is clear to the view, and with that there is a perception of the fitness of every passing suggestion. The volitional energy keeps up the attention on the active search; and the moment that anything in point rises before the mind, it springs upon that like a wild beast upon its prey."

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 brainprocess 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.* 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.t

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

* Compare what is said of the principle of Similarity by F. H. Bradley, Principles of Logic, pp. 294 ff.; E. Rabier, Psychologie, 187 ff.; Paulhan, Critique Philosophique, 2me Série, 1. 458; Rabier, ibid. 460; Pillon, ibid. II. 55; B. P. Bowne, Introduction to Psych. Theory, 92; Ward, Encyclop. Britt. art. Psychology, p. 60; Wahle, Vierteljahrsch. f. wiss. Philos. IX. 426-431.

+ Dr. McCosh is accordingly only logical when he sinks similarity in what he calls the "Law of Correlation, according to which, when we have discovered a relation between things, the idea of one tends to bring up the others" (Psychology, the Cognitive Powers, p. 130). The relations mentioned by this author are Identity, Whole and Parts, Resemblance, Space, Time, Quantity, Active Property, and Cause and Effect. If perceived relations among objects are to be treated as grounds for their appearance before the mind, similarity has of course no right to an exclusive, or even to a predominant, place.

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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.*

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,

* Cf. Bain, Senses and Intellect, 564 ff.; J. S. Mill, Note 39 to J. Mill's Analysis; Lipps, Grundtatsachen, 97.