On the Fourfold Root of the Principle of Sufficient...

That peculiar faculty of the knowing Subject which enables it to obey the will the more readily in repeating representations, the oftener they have already been present to it—in other words, its capacity for being exercised—is what we call Memory. I cannot agree with the customary view, by which it is looked upon as a sort of store-house in which we keep a stock of ready-made representations always at our disposal, only without being always conscious of their possession. The voluntary repetition of representations which have once been present becomes so easy through practice, that one link in a series of representations no sooner becomes present to us, than we at once evoke all the rest, often even, as it were, involuntarily. If we were to look for a metaphor for this characteristic quality of our representative faculty (such as that of Plato, who compared it with a soft mass that receives and retains impressions), I think the best would be that of a piece of drapery, which, after having been repeatedly folded in the same folds, at last falls into them, as it were, of its own accord. The body learns by practice to obey the will, and the faculty of representing does precisely the same. A remembrance is not by any means, as the usual view supposes, always the same representation which is, as it were, fetched over and over again from its store-house; a new one, on the contrary, arises each time, only practice makes this especially easy.

Thus it comes to pass that pictures of our imagination, which we fancy we have stowed away in our memory, become imperceptibly modified: a thing which we realize when we see some familiar object again after a long time, and find that it no longer completely corresponds to the image we bring with us. This could not be if we retained ready-made representations. It is just for this reason too, that acquired knowledge, if left unexercised, gradually fades from our memory, precisely because it was the result of practice coming from habit and knack; thus most scholars, for instance, forget their Greek, and most artists their Italian on their return from Italy. This is also why we find so much difficulty in recalling to mind a name or a line of poetry formerly familiar to us, when we have ceased to think of it for several years; whereas when once we succeed in remembering it, we have it again at our disposal for some time, because the practice has been renewed. Everyone therefore who knows several languages, will do well to make a point of reading occasionally in each, that he may ensure to himself their possession.

This likewise explains why the surroundings and events of our childhood impress themselves so deeply on our memory; it is because, in childhood we have but few, and those chiefly intuitive, representations: so that we are induced to repeat them constantly for the sake of occupation. People who have little capability for original thought do this all their lives (and moreover not only with intuitive representations, but with conceptions and words also); sometimes therefore they have remarkably good memories, when obtuseness and sluggishness of intellect do not act as impediments. Men of genius, on the contrary, are not always endowed with the best of memories, as, for instance, Rousseau has told us of himself. Perhaps this may be accounted for by their great abundance of new thoughts and combinations, which leaves them no time for frequent repetition. Still, on the whole, genius is seldom found with a very bad memory; because here a greater energy and mobility of the whole thinking faculty makes up for the want of constant practice. Nor must we forget that Mnemosyne was the mother of the Muses. We may accordingly say, that our memory stands under two contending influences, that of the energy of the representative faculty on the one hand, and that of the quantity of representations occupying that faculty on the other. The less energy there is in the faculty, the fewer must be the representations, and conversely.

This explains the impaired memory of habitual novel-readers, for it is with them as with men of genius: the multitude of representations following rapidly upon each other, leaves no time or patience for repetition and practice; only, in novels, these representations are not the readers' own, but other people's thoughts and combinations quickly succeeding each other, and the readers themselves are wanting in that which, in genius, counterbalances repetition. The whole thing besides is subject to the corrective, that we all have most memory for that which interests us, and least for that which does not. Great minds therefore are apt to forget in an incredibly short time the petty affairs and trifling occurrences of daily life and the commonplace people with whom they come in contact, whereas they have a wonderful recollection of those things which have importance in themselves and for them.

It is, however, on the whole, easy to understand that we should more readily remember such series of representations as are connected together by the thread of one or more of the above-mentioned species of reasons and consequences, than such as have no connection with one another, but only with our will according to the law of motives; that is to say, those which are arbitrarily grouped. For, in the former, the fact that we know the formal part à priori, saves us half the trouble; and this probably gave rise to Plato's doctrine, that all learning is mere remembering.

As far as possible we ought to try and reduce all that we wish to incorporate in our memory to a perceptible image, either directly, or as an example, a mere simile, or an analogue, or indeed in any other way; because intuitive perceptions take a far firmer hold than any abstract thoughts, let alone mere words. This is why we remember things we have ourselves experienced so much better than those of which we read.