by Aristotle
But one must get hold of a starting-point. This explains why it is that persons are supposed to recollect sometimes by starting from ‘places’. The cause is that they [15] pass swiftly from one point to another, e.g. from milk to white, from white to mist, and thence to moist, from which one remembers Autumn if this be the season he is trying to recollect.
It seems in general that the middle point among all things is a good starting-point. For if one does not recollect before, he will do so when he has come to this, or, if not, nothing can help him; as, e.g. if one were to have in mind A B C D E F [20] G H I. For, if he does not remember at I, he remembers at E; because from E movement in either direction is possible, to D or to F. But, if it is not for one of these that he is searching, he will remember when he has come to C, if he is searching for A or B. But if not, he will remember by going to G, and so in all cases. The cause of one’s sometimes recollecting and sometimes not, though starting from the same [25] point, is, that from the same starting-point a movement can be made in several directions, as, for instance, from C to B or to D. If, then, the mind has not moved in an old path3, it tends to move to the more customary; for custom now assumes the role of nature. Hence the rapidity with which we recollect what we frequently think about. For as one thing follows another by nature, so too that happens by custom;4 and frequency creates nature. And since in the realm of nature occurrences take place which are even contrary to nature, or fortuitous, the same happens a fortiori [452b1] in the sphere swayed by custom, since in this sphere nature is not similarly established. Hence it is that the mind receives an impulse to move sometimes in the required direction, and at other times otherwise, particularly when something else somehow deflects the mind from the right direction and attracts it to itself. This last consideration explains too how it happens that, when we want to remember a name, [5] if we know one somewhat like it, we blunder on to that.
Thus, then, recollection takes place.
But the point of capital importance is that one should know, determinately or indeterminately, the time-relation. There is,—let it be taken as a fact,—something by which one distinguishes a greater and a smaller time; and it is reasonable to think that one does this in a way analogous to that in which one discerns magnitudes. For it is not by the mind’s reaching out towards them, as some say a visual ray from the [10] eye does that one thinks of large things at a distance in space (for even if they are not there, one may similarly think of them); but one does so by a proportionate movement. For there are in the mind similar figures and movements. Therefore, when one thinks of the greater objects, in what will his thinking of those differ from his thinking of the smaller? For all the internal though smaller are as it were proportional. Now, as we may assume within a person something proportional to the [15] forms, so too, we may doubtless assume something else proportional to their distances. It is as though, if one has the movement AB, BE, he constructs CD; for AC and CD are proportional. Why then does he construct CD rather than FG? Is it not because as AC is to AB, so is H to I? These movements therefore he has [20] simultaneously. But if he wishes to think of FG, he thinks of BE in like manner as before; but now, instead of H, I, he thinks of K, L; for these are so related as is FA to BA.
When, therefore, the movement corresponding to the object and that corresponding to its time concur, then one actually remembers. If one supposes he does without really doing so, he supposes himself to remember. For one may be mistaken, [25] and think that he remembers when he really does not. But it is not possible that when one actually remembers he should not suppose himself to remember, but should remember unconsciously. For that is what remembering is. If however, the movement corresponding to the object takes place without that corresponding to the time, or, if the latter takes place without the former, one does not remember.
The movement answering to the time is of two kinds. Sometimes in remembering a fact one has no determinate time-notion of it, no such notion as that, e.g., he did something or other on the day before yesterday; while in other cases he has a [453a1] determinate notion of the time. Still, even though one does not remember with actual determination of the time, he genuinely remembers, none the less. People often say that they remember, but yet do not know when whenever they do not know determinately the exact length of time.
It has been already stated that those who have a good memory are not identical [5] with those who are quick at recollecting. But the act of recollecting differs from that of remembering, not only in respect of time, but also in this, that many also of the other animals have memory, but, of all that we are acquainted with, none, we venture to say, except man, shares in the faculty of recollection. The cause of this is [10] that recollection is, as it were, a mode of inference. For he who endeavours to recollect infers that he formerly saw or heard, or had some such experience, and the process is, as it were, a sort of investigation. But to investigate in this way belongs naturally to those animals alone which are also endowed with the faculty of deliberation; for deliberation is a form of inference.
That the affection is corporeal, i.e. that recollection is a searching for an image [15] in a corporeal substrate, is proved by the fact that some persons, when, despite the most strenuous application of thought, they have been unable to recollect, feel discomfort, which even though they abandon the effort at recollection, persists in them none the less; and especially persons of melancholic temperament. For these [20] are most powerfully moved by images. The reason why the effort of recollection is not under the control of their will is that, as those who throw a stone cannot stop it at their will when thrown, so he who tries to recollect and hunts sets up a process in a material part, in which resides the affection. Those who have moisture around that part which is the centre of sense-perception suffer most discomfort of this kind. For when once the moisture has been set in motion it is not easily brought to rest, until [25] the idea which was sought for has again presented itself, and thus the movement has found a straight course. For a similar reason bursts of anger or fits of terror, when once they have excited such motions, are not at once allayed, even though the angry or terrified persons set up counter motions, but the passions continue to move them on, in the same direction as at first. The affection resembles also that in the case of words, tunes, or sayings, whenever one of them has become inveterate on the lips. [30] People give them up and resolve to avoid them; yet again and again they find themselves humming the forbidden air, or using the prohibited word.
Those whose upper parts are abnormally large, as is the case with dwarfs, have [453b1] abnormally weak memory, as compared with their opposites, because of the great weight which they have resting upon the organ of perception, and because their movements are, from the very first, not able to keep true to a course, but are dispersed, and because, in the effort at recollection, these movements do not easily find a direct onward path. Infants and very old persons have bad memories, owing [5] to the amount of movement going on within them; for the latter are in process of rapid decay, the former in process of vigorous growth; and we may add that children, until considerably advanced in years, are dwarf-like. Such then is our theory as regards memory and remembering—their nature, and the particular [10] organ of the soul by which animals remember; also as regards recollection, its definition, and the manner and causes of its performance.
**TEXT: W. D. Ross, Aristotle: Parva Naturalia, Clarendon Press, Oxford, 1955
1Retaining the MSS reading θνητῶν.
2Retaining τò πάθoς.
3Reading μὴ διὰ παλαιoῦ.
4Reading συνηθείᾳ.
ON SLEEP**
J. I. Beare
1 · With regard to sleep and waking, we must consider what they are; whether they are peculiar to soul or to body, or common to both; and if common, to what part of soul or body they appertain; further, from what cause they are attributes of animals, and whether all animals share in them both, or some partake [15] of the one only, others of the other onl
y, or some partake of neither and some of both.
Further, we must also inquire what dreams are, and from what cause sleepers sometimes dream, and sometimes do not; or whether the truth is that sleepers always dream but do not always remember; and if this occurs, what its explanation [20] is.
Again, we must inquire whether it is possible or not to foresee the future, and if it be possible, in what manner; further, whether it extends only to things to be accomplished by the agency of men, or to those also of which the cause lies in supra-human agency, and which result from the workings of nature, or of spontaneity.
First, then, this much is clear, that waking and sleep appertain to the same part [25] of an animal, inasmuch as they are opposites, and sleep is evidently a privation of waking. For contraries, in natural as well as in all other matters, are seen always to present themselves in the same subject, and to be affections of the same: examples are—health and sickness, beauty and ugliness, strength and weakness, sight and blindness, hearing and deafness. This is also clear from the following considerations. [454a1] The criterion by which we know the waking person to be awake is identical with that by which we know the sleeper to be asleep; for we assume that one who is exercising sense-perception is awake, and that every one who is awake perceives either some external movement or else some movement within himself. If waking, then, consists in nothing else than the exercise of sense-perception, the inference is [5] clear, that that in virtue of which animals perceive, is that by which they wake, when they are awake, or sleep, when they are asleep.
But since the exercise of sense-perception does not belong to soul or body exclusively, then (since the subject of actuality is identical with that of potentiality, and what is called sense-perception, as actuality, is a movement of the soul through the body) it is clear that it is not an affection of soul exclusively, and that a soulless [10] body has not the potentiality of perception.
Now, whereas we have already elsewhere distinguished what are called the parts of the soul, and whereas the nutritive is, in all living bodies, capable of existing without the other parts, while none of the others can exist without the nutritive; it is [15] clear that sleep and waking are not affections of such living things as partake only of growth and decay, e.g. not of plants, because these have not the faculty of sense-perception, whether or not this be capable of separate existence; in potentiality, indeed, and in being it is separable.
Likewise it is clear that there is no animal which is always awake or always [20] asleep, but that both these affections belong to the same animals. For if there be an animal not endued with sense-perception, it is impossible that this should either sleep or wake; since both these are affections of the activity of the primary faculty of sense-perception. But it is equally impossible also that either of these two affections [25] should perpetually attach itself to the same animal, e.g. that some species of animal should be always asleep or always awake; for1 all organs which have a natural function must lose power when they work beyond the time for which they can work; for instance, the eyes tire of seeing, and must give it up; and so it is with the hand and every other member which has a function. Now, if sense-perception is the [30] function of something, this also, if it continues beyond the time for which it can perceive continuously, will lose its power and will do its work no longer. Accordingly, if the waking period is determined by this fact, that in it sense-perception is free; [454b1] if in the case of some contraries one of the two must be present, while in the case of others this is not necessary; if waking is the contrary of sleeping, and one of these two must be present to every animal: it must follow that the state of sleeping is necessary. Finally, if such affection is sleep, and this is a state of powerlessness [5] arising from excess of waking, and excess of waking is in its origin sometimes morbid, sometimes not, so that the powerlessness or dissolution of activity will be so or not; it is necessary that every creature which wakes must also be capable of sleeping, since it is impossible that it should always be actualizing its powers.
So, also, it is impossible for any animal to continue always sleeping. For sleep is [10] an affection of the perceptive part—a sort of bond or motionlessness—so that every creature that sleeps must have a perceptive part. Now, that which is capable of sense-perception in actuality has the faculty of sense-perception; but to actualize this faculty, in the proper and unqualified sense, is impossible while one is asleep. All sleep, therefore, must be susceptible of awakening. Accordingly, almost all [15] other animals are clearly observed to partake in sleep, whether they are aquatic, aerial, or terrestrial, since fishes of all kinds, and molluscs, as well as all others which have eyes, have been seen sleeping. Hard-eyed creatures and insects manifestly assume the posture of sleep; but the sleep of all such creatures is of brief [20] duration, so that often it might well baffle one’s observation to decide whether they sleep or not. Of testaceous animals no direct sensible evidence is as yet forthcoming to determine whether they sleep, but if the above reasoning be convincing to any one, he will be persuaded that they do.
That, therefore, all animals sleep may be gathered from these considerations. For an animal is defined as such by its possessing sense-perception; and we assert that sleep is, in a certain way, or, as it were, a motionlessness bond, imposed on [25] sense-perception, while its loosening or remission constitutes the being awake. But no plant can partake in either of these affections; for without sense-perception there is neither sleeping nor waking. But creatures which have sense-perception have likewise the feeling of pain and pleasure, while those which have these have appetite [30] as well; but plants have none of these affections. A mark of this is that the nutritive part does its own work better when the animal is asleep than when it is awake. [455a1] Nutrition and growth are then especially promoted, a fact which implies that creatures do not need sense-perception to assist these processes.
2 · We must now proceed to inquire into the cause why one sleeps and wakes, and into the particular nature of the sense-perception, or sense-perceptions, if there be several, on which these affections depend. Since, then, some animals possess all [5] the modes of sense-perception, and some not all, not, for example, sight, while all possess touch and taste, except such animals as are imperfectly developed, a class of which we have already treated in our work on the soul; and since an animal when asleep is unable to exercise, in the simple sense, any sensory faculty whatever, it follows that in the state called sleep the same affection must extend to all the senses; [10] because, if it attaches itself to one of them but not to another, then an animal while asleep may perceive with the latter; but this is impossible.
Now, since every sense has something special and also something common; special, as, e.g., seeing is to the sense of sight, hearing to the auditory sense, and so on with the other senses severally; while all are accompanied by a common power, in [15] virtue whereof a person perceives that he sees or hears (for, assuredly, it is not by sight that one sees that he sees; and it is not by taste, or sight, or both together that one discerns, and that sweet things are different from white things, but by a part common to all the organs of sense; for there is one sensory function, and the [20] controlling sensory organ is one, though differing as a faculty of perception in relation to each genus, e. g., sound or colour); and since this subsists in association chiefly with the faculty of touch (for this can exist apart from all the other organs of sense, but none of them can exist apart from it—a subject of which we have treated in our speculations concerning the soul); it is therefore evident that waking and [25] sleeping are an affection of this. This explains why they belong to all animals; for touch alone belongs to all.
For if sleeping were caused by the senses having all undergone some affection, it would be strange that these senses, for which it is neither necessary nor in a manner possible to be active simultaneously, should necessarily all go idle and [30] become motionless simultaneously. For the contrary, viz. that they should not rest simultaneously, would have been more reasonabl
y anticipated. But, according to the explanation just given, all is quite clear regarding those also. For, when the sense organ which controls all the others, and to which all the others are tributary, [455b1] has been in some way affected, it is necessary that these others should be all affected at the same time, whereas, if one of these becomes powerless, there is no necessity for it to do so.
It is indeed evident from many considerations that sleep does not consist in the mere fact that the senses do not function or that one does not employ them, nor even [5] in the inability to exercise the sense-perceptions; for such is what happens in cases of swooning. A swoon means just such impotence of perception, and certain other cases of unconsciousness also are of this nature. Moreover, persons who have the blood-vessels in the neck compressed become insensible. But sleep supervenes when such incapacity of exercise has neither arisen in some chance organ of sense, nor from some chance cause, but when, as has been just stated, it has its seat in the [10] primary organ with which one perceives objects in general. For when this has become powerless all the other sensory organs also must lack power to perceive; but when one of them has become powerless, it is not necessary for this also to lose its power.
We must next state the cause to which sleep is due, and its quality as an affection. Now, since there are several types of cause (for we say that that for the [15] sake of which, and that whence the origin of motion comes, and the matter, and the account, are all causes), in the first place, then, as we assert that nature operates for the sake of an end, and that this end is a good; and that to every creature which is endowed by nature with the power to move, but cannot with pleasure to itself move [20] always and continuously, rest is necessary and beneficial; and since, taught by truth itself, men apply to sleep this metaphorical term, calling it a rest: we conclude that its end is the conservation of animals. But the waking state is the goal, since the exercise of sense-perception or of thought is the goal for all beings to which either of these appertains; inasmuch as these are best, and the goal is what is best. Again, [25] sleep belongs of necessity to each animal. I use the term ‘necessity’ in its conditional sense, meaning that if an animal is to exist and have its own proper nature, it must have certain endowments; and, if these are to belong to it, certain others likewise must belong to it.