Tag Archives: philosophy

Perception Between Sleep & Waking

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First of all, this is obvious, that waking and sleep belong to the same part of the animal. For they are opposites and sleep appears to be a kind of privation of sleep. For opposites always, both in natural cases and otherwise, happen in the same receptive part, and are affections of the same thing. I mean, for example, health and sickness, beauty and homeliness, strength and weakness, seeing and blindness, and hearing and deafness. And yet also it is obvious from these. For by whatever means we distinguish an awake man, by this same means we distinguish a sleeping man. For we consider a a man who is perceiving to be awake, and every one who is awake either perceives something outside himself or motions in himself. If therefore, waking is in nothing other than perceiving, it is obvious that by the same means there is perception, by this same means both waking things are awake and sleeping things sleep. On Sleep and Waking 453b25-454a7

On Sleep and Waking is a small treatise by Aristotle. The starting point of the philosopher’s inquiry is, as good Aristotelian precedent would often tell us, to begin with what is obvious. Waking and sleep are opposites, because sleep is a lack of waking. Presumably, waking could also be described as a lack of sleep, as every insomniac well knows. In general, that is, in every case, opposites occur in the same faculty, with Aristotle providing examples of health and sickness (the faculty of the body) and hearing and deafness (the faculty of the ear). Since we already know that sleeping and waking are opposites, we have merely to determine in which faculty or place they share their common origin. The perceptive ability is this shared “location” when it comes to waking and sleeping. Waking then, is the use or disuse of the perceptive faculty. We will have to wait, when it comes to defining dreams (in his On Dreams), how Aristotle is able to come up with a definition which avoids overlap between the meaning of waking which I just gave, and dreaming.

The Four Predicables: Genus

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A genus is that which is predicated of many things that also differ in their form with respect to their essence. As many things as he who defines appropriately, “What is the thing?,” sitting before him after he has been asked, such things are said to be predicated in their essence. Just as, in the case of “human,” someone appropriately responds that what lies before him is an animal. Connected with the genus as well is whether a thing is in a genus that is the same as another thing or different from another thing. For such a thing falls under a method the same as genus. For having said that “animal” is the genus of human, and likewise the genus of cow, we shall have said that they are in the same genus. But if we shall prove that it is the genus of one, but it is not the genus of the other, we shall have proved that these are not in the same genus. Topica 102a32-102b3

A genus differs in its form, in that essentially, a horse is different from a dog, yet both are nevertheless part of the same genus. Genus is a level of categorization or class somewhat above the direct level of what we might term species, or in the language of Aristotle, things which differ essentially in their form. A cow or ox (βους) is the same genus as a mouse, though both are essentially different. Interestingly, Aristotle seems to describe a method which ascribes a particular genus to a thing quite independent of whether or not another thing shares the same genus. He says both that, “connected with the genus,” is the question of whether a thing is in the same genus as another thing, and also that, “having said that ‘animal’ is the genus of human, and likewise the genus of cow, we shall have said that they are in the same genus.” The impression given is that these twin assessments of two distinct things are conducted separately, and upon reflection, when it turns out man and cow are both “animal,” then we sweep them into the “same genus.” In my view though, it would appear that a comparison is made from the outset, that one is consciously aware of comparing one thing to another, rather than as an independent assessment. Perhaps this is what Aristotle means. For instance he may be pointing out what is rather obvious, but he states the obvious nonetheless, with the goal of prompting us to have an eye on whether something is of the same genus as another thing. The last sentence in this section seems to support this view, as there is language of proof. Thus, whether or not something is of one genus or another, is helpful in proposing or refuting an argument, one of the chief reason the Topica was written. 2

1 Γένος δ’ ἐστὶ τὸ κατὰ πλειόνων καὶ διαφερόντων τῷ
εἴδει ἐν τῷ τί ἐστι κατηγορούμενον. ἐν τῷ τί ἐστι δὲ κατηγο-
ρεῖσθαι τὰ τοιαῦτα λεγέσθω ὅσα ἁρμόττει ἀποδοῦναι ἐρω-
τηθέντα τί ἐστι τὸ προκείμενον· καθάπερ ἐπὶ τοῦ ἀνθρώπου
ἁρμόττει, ἐρωτηθέντα τί ἐστιν, εἰπεῖν ὅτι ζῷον. γενικὸν δὲ (35)
καὶ τὸ πότερον ἐν τῷ αὐτῷ γένει ἄλλο ἄλλῳ ἢ ἐν ἑτέρῳ·
καὶ γὰρ τὸ τοιοῦτον ὑπὸ τὴν αὐτὴν μέθοδον πίπτει τῷ γένει.
διαλεχθέντες γὰρ ὅτι τὸ ζῷον γένος τοῦ ἀνθρώπου, ὁμοίως
δὲ καὶ τοῦ βοός, διειλεγμένοι ἐσόμεθα ὅτι ἐν τῷ αὐτῷ
(102b.) γένει· ἐὰν δὲ τοῦ μὲν ἑτέρου δείξωμεν ὅτι γένος ἐστί, τοῦ
δὲ ἑτέρου ὅτι οὐκ ἔστι, διειλεγμένοι ἐσόμεθα ὅτι οὐκ ἐν τῷ
αὐτῷ γένει ταῦτ’ ἐστίν.

2 See 101a25: The three uses of the treatise are for mental training, conversations and philosophical knowledge/science.

The Four Predicables: Property

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And a property is that which does not make evident the essence of a thing, but it belongs to the thing alone and can be predicated reciprocally of the thing, for example a property of a human is a natural capacity toward grammar. For if he is a human, he has the capacity of grammar, and conversely, if he has the capacity of grammar, he is a human. For no one says that a property is that which is able to belong to another thing, such as sleeping belongs to the human. Not even if the thing happened to belong to it alone for a certain time. And if one of these things would be called a property, it will not be called a property purely, but a temporary property or a property in relation to something else. For, “Being on the right,” is a temporary property, and “Being two-footed,” happens to be a property in relation to something else, such as man is two-footed with respect to a horse or a dog. And it is obvious that of the things able to belong to another thing, none of them are able to be predicated reciprocally. For it is not necessary, if something sleeps, that it is a human. 1
 Topica 102a18-30

After the introduction of “definition,” which is the essence of something, Aristotle transitions to the idea of what a “property” is. Possibly one of the motivations leading Aristotle to discuss property secondly is that there is a common misconception that the property of something simply is its essence. But Aristotle has told us that the essence of something is its definition, not a property. Man, he informs us, has as one of his properties, the ability to understand grammar. But this is only a property insofar as it can be uniquely said of an individual human being as well, and in addition can be mutually said in reverse: i.e. A man is grammar-capable, the one who is grammar-capable is a man.

As one “proof” of his conception, Aristotle, as he often does, seems to appeal to the common opinion and sense of his listeners: “No one says ‘sleeping’ is a property of the human.” In the background of this comment lies the latent idea that people implicitly only attribute properties if they appear to belong uniquely to some one thing. Not only must a property belong to that thing alone, but it must always belong to it. If not, in Aristotle’s eyes, it is merely a temporary or quasi-property. He gives as examples the relative property “being on the right,” relative because it depends on a temporary relation of space and can change. Similarly, “bipedal,” as a biological categorization, is a term created to distinguish it from other animals which have 4 feet.

Near the end of his discussion Aristotle returns to the idea that properties must apply reciprocally to the things they are properties of, and shows the absurdity of disagreeing. “If something sleeps, it is a man,” is absurd. Although one could understandably (and mistakenly) think that sleep is a property of man, the possibility can be tested by “flipping” the subject and predicate and deciding if what ensues is nonsense.

1
Ἴδιον δ’ ἐστὶν ὃ μὴ δηλοῖ μὲν τὸ τί ἦν εἶναι, μόνῳ δ’
ὑπάρχει καὶ ἀντικατηγορεῖται τοῦ πράγματος. οἷον ἴδιον
ἀνθρώπου τὸ γραμματικῆς εἶναι δεκτικόν· εἰ γὰρ ἄνθρωπός (20)
ἐστι, γραμματικῆς δεκτικός ἐστι, καὶ εἰ γραμματικῆς δε-
κτικός ἐστιν, ἄνθρωπός ἐστιν. οὐθεὶς γὰρ ἴδιον λέγει τὸ ἐν-
δεχόμενον ἄλλῳ ὑπάρχειν, οἷον τὸ καθεύδειν ἀνθρώπῳ, οὐδ’
ἂν τύχῃ κατά τινα χρόνον μόνῳ ὑπάρχον. εἰ δ’ ἄρα τι
καὶ λέγοιτο τῶν τοιούτων ἴδιον, οὐχ ἁπλῶς ἀλλὰ ποτὲ ἢ (25)
πρός τι ἴδιον ῥηθήσεται· τὸ μὲν γὰρ ἐκ δεξιῶν εἶναι ποτὲ
ἴδιόν ἐστι, τὸ δὲ δίπουν πρός τι ἴδιον τυγχάνει λεγόμενον,
οἷον τῷ ἀνθρώπῳ πρὸς ἵππον καὶ κύνα. ὅτι δὲ τῶν ἐνδεχο-
μένων ἄλλῳ ὑπάρχειν οὐθὲν ἀντικατηγορεῖται, δῆλον· οὐ γὰρ
ἀναγκαῖον, εἴ τι καθεύδει, ἄνθρωπον εἶναι. (30)