Part 2

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 eternal Nous; but it has its seat in the passive Reason, is dependent upon a physiological process, 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. 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 theory of 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 the pneuma connected with the blood. This is the medium by which the movements arising in the sense organs are transmitted to the heart, and in this pneuma the 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, it becomes 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.” 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 a time in the past, when the perception remembered took place. Memory, then, involves time, and both this and the sense of time are dependent upon 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 objects @of memory@ are images (φανταστὰ). The image is a condition (πάθος) of the central sense. Memory per se is of the original image or perception, and only in an accidental manner does it relate to matters of thought.

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 of the 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 the same 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 think of 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.”

The second chapter of the treatise on memory is devoted chiefly to recollection and the association of ideas. Aristotle distinguishes carefully ¬between¬ the 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. 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 W^m. Hamilton understands the word translated movement (κίνησις) to mean merely change in quality. The word, then, he thinks may be fairly translated into modern nomenclature by his famous term modification. One hesitates to criticise such a profound scholar and such a diligent student of Aristotle as Sir W^m. Hamilton; but in the light of what has been said it seems much simpler and more in accordance with the psychology of Aristotle to understand his 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. 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 W^m. 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 through the mental train, excogitating [what we seek] from [its concomitant in] the present, or some other time and from its Similar or Contrary or Coadjacent. Through this process Reminiscence is effected. For the movements, [which and by which we recollect] are, in these cases, ¬and¬ sometimes the same, sometimes at the same time, sometimes parts 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.”

Wallace quotes the same passage in the introduction to his Psychology of Aristotle, 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 to follow. 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.”

Whichever translation we adopt it seems plain enough that Aristotle maintained that voluntary recollection depended upon the laws of association by similarity, contrast or contrariety, and contiguity. 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.

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 at most 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 of a real lyre; this suggests the musician, and the musician, the song I heard him play.” 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 the desired 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 lower psychic 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.” With Aristotle the 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.” The place of memory among the soul’s functions is, with the phantasy or imagination, mediate between sensation and intelligence.

In connection with Aristotle’s @doctrine@ of recollection, one passage in his Psychology is interesting, although its importance has, perhaps, been exaggerated. “Recollection,” he says, “starts from the soul and terminates in the movements or impressions which are stored up in the organs of sense.” 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. This passage is 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.

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 W^m. Hamilton calls 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 its lenses”, 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.

III.

The Stoics took Plato’s figure of the wax almost literally! They held that the mind is originally a tabula rasa. Sensations are the first writing upon this tablet. The object of sensation makes an impression upon the perceiving subject, as the seal impresses the wax. Memory depends upon this impression. This was the view of Zeno. Chrysippus found difficulties in such a crude materialistic theory. How could the mind receive and retain at the same time a number of different and partly incompatible impressions? Accordingly he replaced this view by the theory that the sense impression consists in @a@ qualitative change (ἀλλοίωσις) of the passively receiving organ, the soul. The presentation (φαντασία) is a state of the soul. The relation of memory to the general theory of knowledge with the Stoics was briefly as follows:—The lowest act of the soul is mere perception (αἴσθησις); the next is presentation (φαντασία), which adds conscious observation, its function being to make a first test of the truth of the material furnished by sense. If perception has offered a true picture of the external object, this presenting activity of the mind becomes so intensive that the understanding is brought into action. The understanding or judgment approves or disapproves the presentations. If it approves, there arises the empirical fact, which bears upon it the mark of truth. These facts memory stores up. By combination of the separate facts empirical concepts are formed which make up the treasure of memory or experience.

The psychology of Epicurus and the other atomists was a simple kind of mechanical sensationalism. Eidola or images from external objects enter the soul through the sense organs. The mind stores up a great multitude of these eidola. Whenever we call up a picture of memory or of the imagination, we turn the attention to one of these images. Thus the mind sees in the same way that the eye does, with this difference, that it perceives much thinner eidola.

Cicero and Quintilian both dwell upon the importance of memory; and both seem to adopt the common theory of the time, that impressions are stamped on the mind as the signets are marked on wax. They are especially concerned, however, with principles relating to the exercise of memory; and they give instructions for mnemonic aids in oratory. Cicero lays special stress upon order as an aid to memory; and as sight is the most acute of the senses, those things are best remembered which are visualized by the imagination. In accordance with the ancient mnemonic systems he would have these imagined forms localized. The advice of Quintilian in respect to memory is especially sensible. According to him, nothing can take the place of exercise and labor. Next in importance is the division and arrangement of one’s subject. He notices also the importance of good health; and says that for slow minds an interval of rest is a good thing, though he seems to be uncertain whether the advantage is due to the rest, or whether it gives reminiscence time to mature.

IV.

The Neo-Platonic psychology of memory is represented by Plotinus. He discusses the subject at considerable length, and presents a somewhat original doctrine. Memory does not belong to God nor to the divine immutable intelligence in man, which knows by direct intellectual perception. It is a function of the soul and first appears when the world soul is individualized in bodies. Memory, however, has no basis in the physical organism, nor does the soul impress the sensations upon the body. The effects of sensations are not like impressions made by a seal, nor are they reactions (ἀντερείσεις), or configurations (τυπώσεις), but in sense-perception as in thought the soul is active. In memory, too, the soul is active, not passive. The influence of the body proves nothing against this. The changeable nature of the body may cause us to forget, but it cannot condition positive recollection. The body is the river of Lethe, but memory belongs to the soul. The part of the soul to which memory belongs is the image-forming faculty. This holds sense impressions as well as thought. Two souls, the higher and the lower, are concerned in memory. When the soul leaves the body, the recollections of the lower soul are soon forgotten in proportion as the higher soul rises toward the intelligible world.

St. Augustine developed the views of the Neo-Platonists in regard to memory. With him memory is a faculty of animals, men, and angels. God, whose immutable essence is above the sphere of movement and change, does not remember. Everything is seen by him in one indivisible and unchangeable present.

Augustine does not agree with Aristotle that some animals are devoid of memory. He attributes memory even to fishes, and relates in confirmation of this opinion an incident that he had observed. There was a large fountain filled with fishes. People came daily to see them and often fed them. The fishes remembered what they received; and as soon as any one came to the fountain they crowded together expecting their accustomed food. But Augustine does not suppose that animals have that higher memory which is purely intellectual, although he probably failed to see how purely mechanical and involuntary their so-called acts of memory are. Memory with St. Augustine, as in the psychology of Plotinus, is a function of the soul, not of the body. But @with@ Aristotle @he@ refers it to the central sense.

What is memory? It is thinking of what one knows. All the various modifications of the soul cannot all be present to us at once. There is a difference between knowing a thing and thinking of it. The musician, says Augustine, knows music, but he does not think of it when he is talking about Geometry. The ideas relating to music are in the mind in a latent state. Augustine anticipates Leibnitz in discussing the unconscious modifications of our ¬own¬ ideas; but he speaks especially of their gradual decay, while Leibnitz considers the unconscious growth of them. “Many numbers”, Augustine says, “are gradually effaced from memory; for they remain not an instant unaltered. Indeed what is not found in memory after a year is somewhat diminished even after one day. But this diminution is imperceptible; yet it is not wrongly inferred; for it does not suddenly all vanish the day before the year is up. Hence we may conclude that from the moment it was engraved in memory it began to slip away.” This doctrine of unconscious mental changes and unconscious mental states is one of the most remarkable features of Augustine’s psychology. With irresistible logic he demonstrates the existence of such states in the following passage from another place:—

“But what when the memory itself loses anything, as falls out when we forget and seek that we may recollect? Where, in the end, do we search, but in the memory itself? And there, if one thing be, perchance, offered instead of another, we reject it, until what we seek meets us; and when it doth we say ‘This is it’; which we should not unless we recognized it, nor recognize it, unless we remembered it——For we do not believe it as something new, but upon recollection, allow what was named to be right. But were it utterly blotted out of the mind, we should not remember it, even when reminded. For we have not as yet utterly forgotten that which we remember ourselves to have forgotten. What, then, we have utterly forgotten, though lost, we cannot even seek after.” It would not be difficult to find passages in modern psychologies that read almost like translations of this chapter of Augustine’s Confessions.

Two kinds of memory—sense memory and intellectual memory are distinguished in the Augustinian psychology. The former preserves and reproduces not only the images of visible objects, but also the impressions of sounds, odors and other objects which strike our senses. The images are not like the eidola of Democritus, but are ideal, formed by the mind from its own essence. Intellectual memory contains our knowledge of the sciences, of literature, and dialectic, and of the questions relating to these subjects. This memory, unlike the memory of sense, contains not the images of things, but the things themselves. These ideas which the intellectual memory stores up are in a sense innate. They never came to us through the senses. They could never have been taught to us, unless we had already had them in our memories. “When I learned them I gave not credit to another man’s mind, but recognized them in mine.” Thus the memory contains the idea of truth and of God.