LECTIO TWENTY-TWO

             § 517. Having considered the objects of the other senses, the Philosopher finally treats of the object of touch, examining this sense last of all because it appears to be the least spiritual of the senses, though it is the foundation of all the others. This section divides into two parts: first he settles certain questions about touch; after which he states the truth about it, at 'It would seem then in general'. The first part again divides into, first a statement, and, secondly, a solution, at 'For every sense', of the problems in question.

             He observes then, first, that in the matters to be examined, the same reasoning holds whether we treat of the tangible or of touch. What is said of one holds good of the other; and if touch is not one sense but several, then the tangible must be, not one kind of sense-object, but several. This he says because, while his intention in general is to define the sense-object first, and after that the sense itself, in the case of touch he is going first to enquire into the sense; and this because the questions he wants to answer are more conveniently dealt with in this way than by treating first of the tangible object. So he prefaces his remarks with a kind of explanation, asserting that it does not matter whether we speak of the tangible or of touch.

             § 518. Of the two questions about touch and the tangible, the first is whether there are several senses of touch or only one; and the second is, what is the place or organ of feeling in touch? i.e. whether flesh is the touch-organ in animals that have flesh (which are those that have blood), and, in those that lack blood, something analogous to flesh; or, on the contrary, is flesh, or what corresponds to flesh, merely the medium of the sense of touch, while its primary organ is something internal, close to the heart? The second opinion is the one maintained in the De Sensu et Sensato.

             § 519. Next, at 'For every sense seems', he begins to answer these questions. With regard to the first he does three things: (a) he gives an argument for the view that there are several senses of touch; (b) he presents a solution of the problem at 'Here is a partial solution'; and (c) he criticises this solution at 'But it is not'. The preliminary argument runs as follows: each single sense appears to bear upon a single pair of contraries, as sight upon white and black, hearing upon high and low, taste upon sweet and bitter; but included in the object of touch are several such pairs, hot and cold, moist and dry, hard and soft, and others of the same kind, besides heavy and light, sharp and blunt and so on. Therefore touch is not one sense, but several.

             § 520. Then, at 'Here is etc.', he gives what might seem to be a solution, saying that one might answer that even in the other senses there appear to be several contrarieties; e.g. in hearing; for in the voice one can observe not only the contrariety of high and low, but that also of loud and soft, rough and smooth, and the like. Similarly colour presents various differences besides the contrariety of black and white, as that one colour is intense, another dull, one beautiful, another ugly. Yet these facts do not mean that either vision or hearing is not a single sense; nor then need the tangible's many contrarieties imply that touch is not a single sense.

             § 521. Then, at 'But it is not clear', he sets aside this solution, saying that all the contraries found in the audible have but one subject, sound; and so too with colour in the visible. But no common subject can be found of all the contraries connected with touch; hence there does not seem to be one genus of tangible, and one sense of touch.

             § 522. To understand this passage we must consider that there is a proportion involved in the distinction between potencies and objects: if a single sense is a single potency, the corresponding object must be a single genus. Now it is shown in the Metaphysics, Book X, that each genus includes one primary contrariety. Hence there must be one primary contrariety in the object of any one sense; and that is why the Philosopher says here that one sense is of one contrariety.

             § 523. However, it is possible for one genus to include several contrarieties beside the primary one, and this either by a process of subdivision--as in the genus body, the first contrariety is between animate and inanimate; and since animate bodies are divided into the sensitive and insensitive, and the sensitive yet again into rational and irrational, contrarieties multiply in the genus body;--or incidentally, as, to take the genus body again, we find the contrariety of white and black, not to mention all the other corporeal accidental qualities. It is thus therefore that we must understand, as regards sound and voice, that, besides the primary contrariety of high and low, which is essential, there are other accidental contrarieties.

             § 524. Now in the genus of tangible things, there are several essential primary contrarieties, which can all in one way be reduced to a single subject, but in another way not; for in one way the subject of the contrariety can be found in the genus, which is related to the various contrary differences as potency to act. In another way the subject of the contraries can be found in the substance, which is itself the subject of the genus in which the contraries are included,--as when we call coloured body the subject of black or white. Speaking then of the subject which is the genus, it is plain that there is no one same subject of all tangible qualities. But speaking of the subject which is substance there is one subject of all these, i.e. the body that pertains to the substance of a given animal. And therefore Aristotle will say that tangible qualities belong to body precisely as body, i.e. they are the qualities by which the elements of body are distinguished from one another. For the sense of touch discriminates among the factors that combine to constitute the animal body. Hence, formally speaking and in the abstract, the sense of touch is not one sense, but several; but it is one substantially.

             § 525. Next, at 'It is not evidence', he deals with the second question; and this in two stages. First, he states the true answer; secondly, he comes to a conclusion that throws some light on the former question, at 'Therefore it appears'. Note then, in the first place, that it might appear that flesh was the organ of sensation in touch, because we feel tangible things on the instant of contact.

             § 526. But, setting this argument aside, he remarks that to decide whether the organ of touch be interior or not (in the latter case the flesh would be the immediate organ of touch) it does not seem sufficient proof that, as soon as the flesh is touched, there occurs a tactual sensation, i.e. one feels; because if one were to extend a skin or tenuous web over the flesh the tangible would be felt immediately on contact with it; yet obviously the organ of touch would not be in the covering membrane. And again, if this web could become a part of one's nature, one would feel all the sooner through it. Hence though at the touch of natural flesh the tangible is felt at once, still it does not follow that the flesh is the organ of touch, but only that it is a natural medium for it.

             § 527. Next, at 'Therefore, it appears', he comes to a conclusion that throws light on the first question, saying that, flesh being a medium adapted to the sense of touch, it would seem that this part of the body has the same sort of relation to sensation as the air around us would have if it were a natural part of us. For though this air is but the medium of sight, smell and hearing, it would appear in that case to be the organ of these senses; and thus it would seem to us that we saw and smelled and heard by a single organ and with a single sense. But in fact just because, as a medium for such sensations, it is 'definite', i.e. distinct from ourselves, we see clearly that it is not an organ. Moreover there are obviously diverse organs for the three senses aforesaid, and therefore a clear distinction of three senses. But it is not so clear in the case of touch; for here the medium is a natural part of us.

             § 528. And he gives a reason for this difference. Air and water, the media of the other senses, could not be a natural part of us, for a living body cannot be constituted of pure air or pure water. These substances, being watery and fluid, are not solid or definite by themselves; they need to be terminated by other things, whereas a living body must be solid and self-contained. Hence the latter needs to be composed of earth and air and water, as required, i.e. as flesh requires in animals that have flesh, and correspondingly for those that have it not. So the body which serves as the medium in touch, i.e. flesh, is able to be naturally conjoined or united with touch in such a way as to transmit the manifold sensations of touch.

             § 529. Then at 'That they are several', he states another fact in support of this. By the tongue also, he says, we obtain several tactile sensations; for by it we feel all the objects of touch that are felt in other parts of the body, and we feel, besides, the flavour or savour that is not perceived in other parts of the body. If the other parts of flesh perceived savours, we should not discriminate between taste and touch, just as we do not in fact discriminate between the touch that discerns hot and cold and that which discerns wet and dry. But it is quite clear that touch and taste are two senses, because they are not mutually transferable: taste does not occur in every part where touch can occur. And the reason why taste is not to be found wherever there is touch is that savours are not qualities of those elements which constitute the bodies of animals; hence they are not, like tangible qualities, of the very substance of an animal.

423a 23-424a 15

THE MEDIUM OF TOUCH CONTINUED ITS ORGAN AND OBJECT

             A problem arises, on the assumption that every body has depth, that is, the third dimension. Bodies having [between them] a medium which is a body cannot touch one another. Now every liquid involves body, and so does everything moistened; it must either be water or contain water. But things in contact with one another in water must necessarily have water as a medium covering their extremities, unless these last be dry. If this is true, it is impossible for one body to touch another in water. The same holds good of air (for air is to the things that are in it as water to things in water) although this fact is less evident to us, just as animals that live in water are unaware that bodies that touch in water are all wet.§§ 530-40

             The question then is, whether there is one way of sensing for all objects of sense, or different ways for diverse objects. The latter at first sight seems to be the case,--taste and touch being effected by contact, the others from a distance. But this is not so: we perceive the hard and the soft through something intervening, just as we do the audible and the visible and the odorous. But of these objects, some operate at a distance, others close at hand. That is why the fact escapes us: we do perceive everything through a medium, but the fact is not evident in the latter cases. Indeed, as we said before, if we were to perceive all tangible objects through a membrane, not knowing what was interpolated, we should think we touched the objects themselves, as we now do in air and water: for in these cases we think we touch the objects and that there is no medium.§§ 541-2

             But the tangible differs from the visible and the audible; for we perceive the latter in that the medium itself produces some effect in us; whereas the tangible does not affect us through the medium so much as with the medium, simultaneously, as when one is struck on a shield. For the shield does not strike its holder after it is itself struck; but the two are struck at once.§§ 543-4

             It would seem in general that flesh and the tongue stand to the sense-organ precisely as water and air to sight and hearing and smell, each to its respective sense. When the sense organ is touched (as when one places a white object on the surface of the eye), no sensation is produced in either case. Hence the organ of the tangible is internal; for the same thing happens in this sense as in the others; what is placed on the organ they do not perceive. What, however, is placed on the flesh they do perceive; flesh, then, is the medium of touch.§ 545

             Tangible objects vary therefore with differences of body as such--I mean the differences by which the elements are distinguished as hot and cold, wet and dry, as is stated in our work on the elements. The sense organ for these, the tactile, in which the sense called touch is principally lodged, is the part in potency to these qualities. For to perceive is to receive an impression. Hence whatever makes the organ to be such as itself is actually, does so, the organ being in potency thereto. Hence we do not perceive what has heat, or cold or hardness or softness to an exact similitude of our own heat, and so forth, but rather the extremes of these: the sense being, as it were, in a mean state between the contrary extremes in the objects perceived; which is how it discriminates between them. For a mean is discriminative; in the presence of either extreme it becomes the contrary one. Hence, as whatever is to perceive black or white must have neither of these in itself actually, but both potentially (and so with the other sense-objects), so touch must be actually neither hot nor cold.§§ 546-8

             Further: as sight is, in a way, of the visible and the invisible (and similarly with the rest of such opposites), so touch is of both the tangible and the intangible. The intangible is that which has the distinguishing quality of tangibles to a very small extent, as air is affected; and also the excessively tangible, such as things destructive.

             We have now said in outline something about each of the senses.§§ 549-50