The Neo-Platonic psychology of memory is represented by Plotinus.[[32]] 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.[[33]]
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.[[34]]
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.[[35]] 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”,[[36]] 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.”[[37]] 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.”[[38]] 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.[[39]] 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.[[40]] 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.
Augustine points out, too, what has been repeated by Locke and others until it has become a platitude, that we do not remember objects themselves, but the ideas which we have gained from them. And with his usual subtlety he shows that much of what is ordinarily attributed to perception is really the work of memory.
“We see what importance St. Augustine attaches to memory. It is in his view the faculty which preserves the ideas relating not only to the body, but to the soul, not only to eternal truths, but to the Eternal Being himself——. This memory, which is peculiar to man, and which animals do not possess—this memory, which in a mysterious manner contains in it intelligible realities, is, according to the Bishop of Hippo, one of the three great faculties of man, and the origin of the other two. It is from it that intelligence arises, and the will proceeds from the one to the other and unites them. Thus, if it is allowed to compare things human with things divine, we have in us an image of the august Trinity. Memory, in which is the matter of knowledge, and which is as the place of intelligible things, offers some resemblance to the Father; the intellect, which is derived from and formed from it, is not without analogy to the Son; and love or will, which unites the intelligible (or memory) to the intellect has a certain resemblance to the Holy Spirit.”[[41]] The phenomena of memory were also important with Augustine as weapons against materialism. By memory the soul knows objects of sense when it no longer perceives them, and, moreover, combines the heterogeneous in ways inexplicable by means of a physchical substance. And again the soul can form abstract conceptions of space and mathematical truths.
The well-known conditions of a good memory, such as acuteness of sensation, order, and repetition, Augustine notices only incidentally. More attention is given to the relation of the will to memory and to the association of ideas.
Whether we remember or not depends upon the will. By an act of will we avert the memory from sense-perceptions, as, for example, when we hear a speaker and do not notice what he says, or read a page and do not know what we have read, or walk with our attention upon something else. In all these cases we perceive, but do not remember our perceptions. So, too, recollection depends upon the will: “As the will applies the sense to the body (or external object), so it applies the memory to the sense, and the eye of the mind of the thinker to the memory.”[[42]]