II.
The difference in philosophic method between Plato and Aristotle is well illustrated by their treatment of memory. What Plato says of memory is incidental to the discussion of such profound matters as the nature of the soul and the theory of knowledge. Memory, according to him, is one of the higher faculties and partakes of the eternal nature of the soul. Aristotle makes a special study of memory in a less transcendental way. With him it is no longer a function of the eternalNous; but it has its seat in the passive Reason, is dependent upon a physiologicalprocess, and perishes with the body.
Aristotle seems to have been the first of ancient philosophers to write a systematic treatise on psychology. But, rather curiously, in this work on psychology there is no special treatment of memory. A special tract, however, was devoted to the subject.[9]This, so far as we know, was the first scientific study of memory; and for this reason, as well as for its intrinsic merits, the tract deserves special attention. But before passing to his doctrine of memory, it is well to notice briefly his theoryof sense-perceptions. On occasion of appropriate stimuli movements take place in the sense-organs. These movements, however, are not sense perception. In perception the mind must compare and distinguish disparate sensations; it must unite the sensations presented simultaneously by our double sense organs as of sight and hearing, and it must be conscious of sensation. This work of comparison, of psychic synthesis, and of self-conscious perception is performed by a central sense. The physical basis of this sense is the heart. Through it the mind performs the act of sense perception. The functions now attributed to nervous substance are referred by Aristotle to thepneumaconnected with the blood. This is the medium by which the movements arising in the sense organs are transmitted to the heart, and in thispneumathe movements persist long after the external stimuli have ceased to act. Incidentally, it is interesting to note, that according to Aristotle’s psychology, the brain has very little to do with mental activity. To borrow a phrase from Wallace, it serves simply as “a cooling apparatus to counteract the excessive warmth of the heart.” When the movement occasioned in the sense organ by an external stimulus is propagated to the heart,[10]itbecomes a perception of the soul. Sense perception, then, is an act of the soul by means of a physiological process. In the words of Aristotle it is “a movement of the soul through the body.”[11]Now this movement sometimes continues after the stimulus, which was the occasion of it, has ceased to act. The extreme case is the well known phenomenon of a visual after-image. The images of the imagination are such after-sensations. Imagination is weak sensation, or in the words of Hobbes, “decaying sense”. So too,dreaming is the result of a movement in our bodily organs, caused either from without or from within. Again, these persisting movements are the elements of memory.
At first, one wonders how Aristotle will distinguish those movements which constitute memory from those which are the basis of imagination. He is not entirely satisfactory on this point; but he makes the following distinction. The picture of the imagination, or the corresponding movement does not refer to an external object, and is not located in the past. The memory picture, on the other hand, does refer to an object and carries with it the consciousness of atime in the past, when the perception remembered took place.[12]Memory, then, involves time, and both this and the sense of time aredependentupon the central sense. Memory, as we have seen, is dependent upon the residua of sensations. The subjective side of a sensation is an image. Thus memory belongs to the same part of the soul as the imagination, and the proper objectsof memoryare images (φανταστὰ). The image is a condition (πάθος) of the central sense. Memoryper seis of the original image or perception, and only in an accidental manner does itrelate to matters of thought.[13]
In his special tract on memory, Aristotle in part repeats Plato’s views, in part discusses the obvious facts of memory, which, having been continually repeated since his time, have become mere platitudes, and in part he tries to explain the phenomena of memory in accordance with his general system of psychology. The essay, however, is of special interest, because in it Aristotle sets forth very clearly the famous doctrine of association of ideas. Some ofthe other points in the treatise may be briefly mentioned and special consideration given to the portion relating to recollection and association. ¶ First Aristotle takes considerable space to show what would seem to be apparent enough to everybody, that memory is of the past, as perception is of the present, and hope and opinion of the future.
The central sense or sensorium must be in a condition suitable to receive and retain impressions. If the sensorium is too hard, no impression is made. If it is greatly agitated, the new movement is ineffectual: on somewhat thesame principle, one may suppose, as one say in modern psychology, that a weak stimulus is washed out by a strong one. Hence the very young and the very old have poor memories; for the former are in the movement of growth, the latter in that of decay. Again, the question arises: How is it that in recollection we recognize the memory image as a picture of the absent object? A scholastic answer is given. “An animal painted in a picture, he says, is both an animal and a copy, and while being thus one and the same, it is nevertheless two things at once. The animal and the copy are not identical, and we may thinkof the picture either as animal or as a representation. This is also true of the image within us; and the idea which the mind contemplates is something, although it is also the image of something else.”[14]
The second chapter of the treatise on memory is devoted chiefly to recollection and the association of ideas. Aristotle distinguishes carefullybetweenthe mere persistence and reproduction of a presentation (μνήμη) from voluntary recollection (ἀνάμνησις). The latter is indirect reproduction.It is possible only by the association of ideas. The former is an attribute of animals, while the latter is peculiar to man. Recollection occurs according to the sequence of ideas.[15]What and how necessary the sequence shall be depends upon our past experience.“If the sequence be necessary”, Aristotle continues, “then, when this movement occurs, that one will follow. If it is not necessary, but a matter of habit, the latter movement will generally follow.” Sir Wm. Hamilton understands the word translatedmovement(κίνησις) to mean merelychange in quality. The word, then, he thinks may be fairly translated into modern nomenclature by his famous termmodification. One hesitates to criticise such a profound scholar and such a diligent student of Aristotle as Sir Wm. Hamilton; but in the light of what has been said it seems much simpler and more in accordance with the psychology of Aristotle to understandhis doctrine of recollection as follows: The physiological movements originally connected with a series of perceptions must occur again in the same order when we recall a true memory-picture.[16]Man is so constituted that when one movement and the mental image connected with it occur, another movement with its appropriate mental image is likely to follow. When we would recall anything, therefore, we must call up idea after idea until we arrive at one upon which the one we are in search of has often been sequent in our experience.Or in terms of physiology, movement after movement must recur until we arrive at a movement upon which the movement corresponding to the idea desired has often been sequent.
This sequence or association of ideas is subject to certain laws. The remarkable passage in which Aristotle states these laws is translated by Sir Wm. Hamilton as follows:
“When, therefore, we accomplish an act of Reminiscence we pass through a certain series of precursive movements until we arrive at a movement, on which the one we are in quest of is habitually consequent. Hence, too, it is that we hunt throughthe mental train, excogitating [what we seek] from [its concomitant in]the present,or some other timeand from itsSimilarorContraryorCoadjacent. Through this process Reminiscence is effected. For the movements, [which and by which we recollect] are, in these cases,andsometimes thesame, sometimes atthe same time, sometimesparts of the same whole: so that [having obtained from one or the other of these a commencement], the subsequent movement is already more than half accomplished.”[17]
Wallace quotes the same passage in the introduction to his Psychology of Aristotle,[18]and gives the following somewhat different and probably more accurate translation:—
“When engaged in recollection we seek to excite some of our previous movements until we come to that which the movement or impression of which we are in search was wont tofollow. And hence we seek to reach this preceding impression by starting in our thought from an object present to us or something else whether it be similar, contrary, or contiguous to that of which we are in search; recollection taking place in this manner because the movements are in one case identical, in another case coincident and in the last case partly overlap.”[19]
Whichever translation we adopt it seems plain enough that Aristotle maintained that voluntary recollection depended upon the laws of association bysimilarity,contrastorcontrariety, andcontiguity. Very likely he meant to include simultaneity and sequence; but any proof of this should rest upon the general import of the passage rather than upon any doubtful emendation like Hamilton’s.[20]
A more important question is whether Aristotle meant to limit the application of these laws to voluntary recollection (ἀνάμνησις), or whether he intended to include spontaneous reproduction (μνήμη) as well.
The opinion commonly held by students of Aristotle, from Themistius down, has been that he applied the law of association only to voluntary recollection. Hamilton, however, argues forcibly that Aristotle taught the universality of the law of association. It seems natural enough to suppose that one who saw so clearly that in the voluntary train of thought the sequence conforms to the law of association, would have seen that the same laws apply to the spontaneous activity of the mind. But while Aristotle states the law of association clearly for the former, he atmost merely alludes to the latter, and obscurely enough at that. Later in the same treatise Aristotle gives an illustration that may serve to elucidate the principles of association that have just been stated. In recollection there are certain movements which serve as standpoints or clues. Milk suggests whiteness, whiteness the clear atmosphere,the atmosphere moisture,this the rainy season. So too, Themistius in commenting upon the passage quoted above, uses an illustration somewhat similar. “I see a painted lyre, and moved by this, as the prior and leading image, I have the reminiscence ofareal lyre; this suggests themusician, and the musician, the song I heard him play.”[21]Again, Aristotle uses an illustration somewhat as follows: Let A. B. C. D. E. F. G. H. represent a series of ideas, one of which we will to recall. From D E, as a starting point we may be moved forward by E or backward by D, by the association of ideas. If, then, on the suggestion of D E, we do not find what we would recall, we may find it by running over the series E ... H; if not, we shall at any rate find thedesired idea by running over the series backward from D to A. Not much stress, however, should be put upon this last illustration; for the text is so obscure that many different interpretations have been given by commentators. Perhaps Aristotle meant to illustrate something more profound than the mere linkings of presentations in a series, and the process of recollecting the mental train. But the illustration of such a simple matter as this was not unimportant in the first scientific study of memory.
The place of memory in the Aristotelian psychology in relation to the lowerpsychic activities is plain from what has been said. The relation of memory, as voluntary recollection, to the higher activity of the Nous is indicated by Aristotle when he says that recollection is a syllogistic process. Thus it is that, while many animals have the lower kind of memory, man alone has the higher form. “The reason is”, says Aristotle, “that Reminiscence is, as it were, a kind of syllogism, or mental discourse. For he who is reminiscent, that he has formerly seen or heard, or otherwise perceived, anything virtually performs an act of syllogism.”[22]With Aristotlethe higher functions of the soul are based upon the lower. “Without nutrition, there is no sense; without sense there is no phantasy; without phantasy there is no cogitation or intelligence.”[23]The place of memory among the soul’s functions is, with the phantasy or imagination, mediate between sensation and intelligence.
In connection with Aristotle’sdoctrineof recollection, one passage in his Psychology is interesting, although its importance has, perhaps, been exaggerated. “Recollection,” he says, “starts from the soul and terminatesin the movements or impressions which are stored up in the organs of sense.”[24]Siebeck interprets this passage as meaning that the soul has the power by means of the heart to effect a sort of efferent movement towards the sense organs and thus to arouse anew the persisting residua of former motions. Recollection, then, with Aristotle as in modern psychology, is an excitation of the sense organs, reproduced in a less degree; and the same organs are excited and the same movements repeated as in the original sensation.[25]This passageis certainly a remarkable anticipation of Bain’s famous doctrine that a reproduced impression “occupies the very same parts and in the same manner” as the original impression.[26]
In the foregoing sketch of Aristotle’s view of memory the attempt has been made to give only what can fairly be found in Aristotle’s text. Much of his tract upon memory is obscure. Commentators have held very conflicting opinions in regard to the importance of what he wrote upon association and recollection. Sir Wm. Hamiltoncalls him “the founder and finisher of the theory of Association,” looks upon the commentators as marvellously stupid in their interpretations, and deems it a proof of Aristotle’s genius that it took the world 2000 years to become intelligent enough to understand him. Indeed, in reading Hamilton’s erudite discussion one may be led almost to believing that Aristotle was the first Scottish philosopher. But while Hamilton’s Scottish apperception probably found too much in Aristotle’s treatise, and while, on the other hand, Lewes may be right in saying that “here as in so many other cases modern knowledge supplies the telescope with itslenses”, nevertheless Aristotle’s doctrine of association was a valuable contribution to science. And it is manifestly unfair to charge him with ignorance of its importance, because he did not spin out as many volumes upon the subject as the English associationalists have done.[27]