Lecture 12 — Touch: the fundamental sense

It is clearly impossible for the body of an animal to be simple—I mean made of fire, for instance, or air. For no other sense can exist without touch, since every animate body, as we have seen, is tactual. The sense organs, indeed, can be constituted of all the elements (except earth), for they effect sensation by sensing through something other than the sensitive body itself, namely, the medium. But touch occurs by touching things; that is also why it has this name. Other senses no doubt also sense by a touch, but through other things; touch alone, it would seem, does this through itself.

Hence the body of an animal will not be of such elements as these, nor yet be earthy. For touch is a kind of mean between all tangible objects and is receptive, not only of all the differences of earth, but also of hot and cold and all other things that can be touched. This is why we do not feel with such parts of our bodies as bones and hair, because they are earthy. Plants, too, lack sensitivity for the same reason—they are of earth; and without touch no other sense can exist; and this sense does not consist either of earth or of any other single element.

It is, then, evident that animals would die if they were deprived of this sense alone. For it is neither possible for what is not an animal to possess this, nor, to be an animal, is any other necessary.

And this again is why the other sense-objects (e.g., color, smell, and sound), by their excessive intensity, do not corrupt the animal, but only the senses—except accidentally, as when, for example, blasts and blows accompany noise; or when other things are set in motion, by objects seen or smelled, which destroy by contact; and flavor too, insofar as it happens also to be tangible, may destroy thus.

But an excess of tangible qualities, of heat or cold or hardness, destroys the animal itself. For as any excess in the sense-object corrupts the sense, an excess in the object of touch can destroy touch; and by touch life itself is defined. For it has been shown that an animal cannot live without touch. Hence it is clear that the excess of a tangible object corrupts not only the sense but also the animal, inasmuch as only this sense is strictly necessary to animal life.

But, as we have said, the animal has the other senses not for the sake of its being, but for the sake of its well-being.

For example, it has sight because it lives in air or water (and generally, in what is transparent), so that it might see things.

Taste it has on account of the pleasant or painful, so that it may sense both what it desires in food and so be moved towards it.

Hearing it has so that something might be signified to it, and a tongue to signify something to someone else.

865. It is clearly impossible for the body (435a11). After proving that touch must exist in all animals, the Philosopher now sets out to show that it is clearly impossible for the body of an animal to be simple: for instance, to be made of fire, or air—as the Platonists thought when they imagined animals made of air. He argues this from the fact that no other sense can exist without touch, and that, therefore, as he has said already, every animal must have touch. (Bk. 2, lect. 3, nn. 249, 252.) Consequently, every animate body, that is, animated with a sensitive soul, must be such that the sense of touch can arise in it. But all the elements (except earth) can be organs of, or the media for, the other senses: air and water, for instance, because they effect sensation through something other than the sensitive body itself, that is, through a medium. But touch does not occur through a medium, but by touching the sensible objects themselves. That is why it is so named. Whereas the other senses sense by a sort of contact, but through a medium, not immediately. (For the sense-object touches the sense through the medium just as it modifies it through the medium.) The sense of touch alone senses by touching the sense-object through itself, and with no medium.

866. From which it is clear that the animal body must be such that touch can arise in it, but not such that sight or hearing can arise in it; for these senses arise through an extrinsic medium. And since the animal body must be such that touch can arise for it, it is impossible that the body of an animal* is *of such elements as these—not of earth, for the other senses do not arise through it, nor of any of those other elements, through which the other senses come to be.

867. The reason is that that whereby touch occurs must be balanced midway between the various tangible qualities, so that it is receptive of them, insofar as it exists in potency to them, as we have seen already. (Bk. 2, lect. 22, nn. 521–24; bk. 3, lect. 11, n. 849.) And this is true with respect to all tangible qualities, not to those of earth alone. Now, simple bodies cannot be thus balanced in an intermediate way; rather, they are found to have one or other of opposed qualities to an extreme degree. Hence, it is manifest that the sense of touch can arise through no simple body, nor any body approximating the simple bodies. Therefore this is why we do not feel with such parts of our bodies as bones and hair, because in them what belongs to earth is not reduced to an intermediate, as touch requires.

868. It is for the same reason that plants too lack sensitivity, because they contain too much of what is earthy, and without touch no other sense can exist, nor is touch able to arise through some other element. It is manifest, then, that no simple body can be ensouled by the sensitive soul.

869. Then, at it is, then, evident (435b4), as a conclusion from what has been said, he shows how all the senses are related to animals:

first, with regard to the sense of touch;

second, at but, as we have said, the animal (435b19; [872]), to the other senses.

First, then, he observes that, touch being necessary for all animals, as has been shown, it is evident that animals would die if deprived only of this sense, touch. (Lect. 11, nn. 849, 852.) For this sense is indeed convertible with animality: for nothing can have it unless it is an animal, nor can something be an animal unless it has this sense.

870. And he further concludes that, while the objects of the other senses, if they are extremely intense, do in fact corrupt each of these powers of sense (as excessive brightness destroys sight, and excessive noise destroys hearing), yet because, even with these senses destroyed, the animal can survive, these excesses do not corrupt the animal, except accidentally—inasmuch as accidentally the animal is also acted upon by certain tangible things that are corruptive, as when blasts and blows accompany noise, as in thunderstorms, for instance, in which animals sometimes die.

So also, certain things die due to things that are seen, but not precisely insofar as they are seen but rather insofar as they infect the air, as is said of certain poisons. So too, one should understand smells, insofar as along with bad odors sometimes is conjoined a corruption of the air. Similarly, a taste might harm an animal, not precisely as a taste, but as accompanied by some tangible quality, for example, as such a taste results from an excessive heat or cold.

871. But the excessive intensity of tangible qualities does corrupt the animal through itself and not accidentally. For as any excess in the sense-object corrupts the sense, an excess in the object of touch, that is, the tangible, can destroy touch, if it is exceedingly intense; and it is in reference to this sense that an animal’s life is determined. For the life of an animal endures just so long as the sense of touch endures in it. For it has been shown that an animal cannot live without touch. Hence it is clear that the excessive intensity of a tangible object corrupts not only the sense of touch*, but* it also corrupts the animal, inasmuch as it is necessary for only this sense that it be present in an animal.

872. Then, at but, as we have said, the animal (435b19), he relates the other senses to the animal; the animal has the other senses, he says, not for the sake of a need of its being, since it can exist and live without them, but for the sake of its well-being. (Lect. 11, n. 861.) For example, an animal has sight because it lives in air or water, so that it might see things at a distance through air or water—and not only through air and water, but through any transparent medium, since we even see through the heavenly bodies. Similarly, an animal has taste on account of the pleasure and pain it finds in its food; so that it may sense pleasure in the food and thereby desire it and be moved to seek it out.

873. Notice that previously he asserted that taste is necessary for an animal insofar as it is a certain touch belonging to food, whereas here he counts it among the senses that are not necessary, insofar as it discriminates between flavors, which latter make food pleasant or painful so that it more readily be accepted or rejected. And what is said of taste should also be understood of the sense of smell, since through odors animals are drawn to food that is distant—though indeed in man, as he explains in On Sense and What is Sensed, smell also has a different species and utility. (Aristotle, On Sense and What is Sensed, ch. 5, 443b17–444a19; cf. Aquinas, Commentary on Aristotle’s On Sense and What is Sensed, ch. 13.)

874. But hearing is in the animal so that something might be signified to it. For it is necessary that the conceptions of one animal be signified to another insofar as one animal is helped by another; this is especially clear in the gregarious animals and in all animals wherein the young are reared by the parents. Hence, too, the tongue is necessary so that one animal might signify, by its sound, its feelings to another.

Let this suffice for the present concerning the soul.