The Basic Works of Aristotle (Modern Library Classics) (97 page)

10
     What can be tasted is always something that can be touched, and just for that reason it cannot be perceived
through
an interposed foreign body, for touch means the absence of any intervening body.
(10)
Further, the flavoured and tasteable body is suspended in a liquid matter, and this is tangible. Hence, if we lived in water, we should perceive a sweet object introduced into the water, but the water would not be the medium
through
which we perceived; our perception would be due to the solution of the sweet substance in what we imbibed, just as if it were mixed with some drink. There is no parallel here to the perception of colour, which is due neither to any blending of anything with anything, nor to any efflux of anything from anything. In the case of taste, there is nothing corresponding to the medium in the case of the senses previously discussed; but as the object of sight is colour,
(15)
so the object of taste is flavour. But nothing excites a perception of flavour without the help of liquid; what acts upon the sense of taste must be either actually or potentially liquid like what is saline; it must be both (
a
) itself easily dissolved, and (
b
) capable of dissolving along with itself the tongue.
(20)
Taste apprehends
both (
a
) what has taste and (
b
) what has no taste, if we mean by (
b
) what has only a slight or feeble flavour or what tends to destroy the sense of taste. In this it is exactly parallel to sight, which apprehends both what is visible and what is invisible (for darkness is invisible and yet is discriminated by sight; so is, in a different way, what is over-brilliant), and to hearing, which apprehends both sound and silence, of which the one is audible and the other inaudible,
(25)
and also over-loud sound. This corresponds in the case of hearing to over-bright light in the case of sight. As a faint sound is ‘inaudible’, so in a sense is a loud or violent sound. The word ‘invisible’ and similar privative terms cover not only (
a
) what is simply without some power, but also (
b
) what is adapted by nature to have it but has not it or has it only in a very low degree, as when we say that a species of swallow is ‘footless’ or that a variety of fruit is ‘stoneless’. So too taste has as its object both what can be tasted and the tasteless—the latter in the sense of what has little flavour or a bad flavour or one destructive of taste.
(30)
The difference between what is tasteless and what is not seems to rest ultimately on that between what is drinkable and what is undrinkable—both are tasteable, but the latter is bad and tends to destroy taste, while the former is the normal stimulus of taste. What is drinkable is the common object of both touch and taste.
[422b]

Since what can be tasted is liquid, the organ for its perception cannot be either (
a
) actually liquid or (
b
) incapable of becoming liquid. Tasting means a being affected by
⁴⁰
what can be tasted as such; hence the organ of taste must be liquefied, and so to start with must be non-liquid but capable of liquefaction without loss of its distinctive nature.
(5)
This is confirmed by the fact that the tongue cannot taste either when it is too dry or when it is too moist; in the latter case what occurs is due to a contact with the pre-existent moisture in the tongue itself, when after a foretaste of some strong flavour we try to taste another flavour; it is in this way that sick persons find everything they taste bitter, viz. because, when they taste, their tongues are overflowing with bitter moisture.

The species of flavour are,
(10)
as in the case of colour, (
a
) simple, i. e. the two contraries, the sweet and the bitter, (
b
) secondary, viz. (i) on the side of the sweet, the succulent, (ii) on the side of the bitter, the saline, (iii) between these come the pungent, the harsh, the astringent, and the acid; these pretty well exhaust the varieties of flavour.
(15)
It follows that what has the power of tasting is what is potentially
of that kind, and that what is tasteable is what has the power of making it actually what it itself already is.

11
     Whatever can be said of what is tangible, can be said of touch, and vice versa; if touch is not a single sense but a group of senses, there must be several kinds of what is tangible. It is a problem whether touch is a single sense or a group of senses. It is also a problem,
(20)
what is the organ of touch; is it or is it not the flesh (including what in certain animals is homologous with flesh)? On the second view, flesh is ‘the medium’ of touch, the real organ being situated farther inward. The problem arises because the field of each sense is according to the accepted view determined as the range between a single pair of contraries, white and black for sight, acute and grave for hearing, bitter and sweet for taste; but in the field of what is tangible we find several such pairs,
(25)
hot cold, dry moist, hard soft, &c. This problem finds a partial solution, when it is recalled that in the case of the other senses more than one pair of contraries are to be met with, e. g. in sound not only acute and grave but loud and soft,
(30)
smooth and rough, &c.; there are similar contrasts in the field of colour. Nevertheless we are unable clearly to detect in the case of touch what the single subject is which underlies the contrasted qualities and corresponds to sound in the case of hearing.

To the question whether the organ of touch lies inward or not (i. e. whether we need look any farther than the flesh), no indication in favour of the second answer can be drawn from the fact that if the object comes into contact with the flesh it is at once perceived.
[423a]
For even under present conditions if the experiment is made of making a web and stretching it tight over the flesh, as soon as this web is touched the sensation is reported in the same manner as before, yet it is clear that the organ is not in this membrane. If the membrane could be
grown
on to the flesh, the report would travel still quicker.
(5)
The flesh plays in touch very much the same part as would be played in the other senses by an air-envelope growing round our body; had we such an envelope attached to us we should have supposed that it was by a single organ that we perceived sounds, colours, and smells, and we should have taken sight, hearing, and smell to be a single sense. But as it is, because that through which the different movements are transmitted is not naturally attached to our bodies,
(10)
the difference of the various sense-organs is too plain to miss. But in the case of touch the obscurity remains.

There must be such a naturally attached ‘medium’ as flesh, for no living body could be constructed of air or water; it must be something
solid. Consequently it must be composed of earth along with these, which is just what flesh and its analogue in animals which have no true flesh tend to be.
(15)
Hence of necessity the medium through which are transmitted the manifoldly contrasted tactual qualities must be a body naturally attached to the organism. That they are manifold is clear when we consider touching with the tongue; we apprehend at the tongue all tangible qualities as well as flavour. Suppose all the rest of our flesh was, like the tongue,
(20)
sensitive to flavour, we should have identified the sense of taste and the sense of touch; what saves us from this identification is the fact that touch and taste are not always found together in the same part of the body. The following problem might be raised. Let us assume that every body has depth, i. e. has three dimensions, and that if two bodies have a third body between them they cannot be in contact with one another; let us remember that what is liquid is a body and must be or contain water,
(25)
and that if two bodies touch one another under water, their touching surfaces cannot be dry, but must have water between, viz. the water which wets their bounding surfaces; from all this it follows that in water two bodies cannot be in contact with one another. The same holds of two bodies in air—air being to bodies in air precisely what water is to bodies in water—but the facts are not so evident to our observation,
(30)
because we live in air, just as animals that live in water would not notice that the things which touch one another in water have wet surfaces.
[423b]
The problem, then, is: does the perception of all objects of sense take place in the same way, or does it not, e. g. taste and touch requiring contact (as they are commonly thought to do), while all other senses perceive over a distance? The distinction is unsound; we perceive what is hard or soft,
(5)
as well as the objects of hearing, sight, and smell, through a ‘medium’, only that the latter are perceived over a
greater
distance than the former; that is why the facts escape our notice. For we do perceive everything through a medium; but in these cases the fact escapes us. Yet, to repeat what we said before, if the medium for touch were a membrane separating us from the object without our observing its existence,
(10)
we should be relatively to it in the same condition as we are now to air or water in which we are immersed; in their case we fancy we can touch objects, nothing coming in between us and them. But there remains this difference between what can be touched and what can be seen or can sound; in the latter two cases we perceive because the medium produces a certain effect upon us, whereas in the perception of objects of touch we are affected not
by
but
along with
the medium; it is as if a man were struck through his shield,
(15)
where the shock is not first
given to the shield and passed on to the man, but the concussion of both is simultaneous.

In general, flesh and the tongue are related to the real organs of touch and taste, as air and water are to those of sight, hearing, and smell. Hence in neither the one case nor the other can there be any perception of an object if it is placed immediately upon the organ,
(20)
e. g. if a white object is placed on the surface of the eye. This again shows that what has the power of perceiving the tangible is seated inside. Only so would there be a complete analogy with all the other senses. In their case if you place the object on the
organ
it is not perceived, here if you place it on the flesh it
is
perceived; therefore flesh is not the organ but the
medium
of touch.
(25)

What can be touched are distinctive qualities of body
as
body; by such differences I mean those which characterize the elements, viz. hot cold, dry moist, of which we have spoken earlier in our treatise on the elements.
⁴¹
The organ for the perception of these is that of touch—that part of the body in which primarily the sense of touch resides.
(30)
This is that part which is potentially such as its object is actually: for all sense-perception is a process of being so affected; so that that which makes something such as it itself actually is makes the other such because the other is already potentially such.
[424a]
That is why when an object of touch is equally hot and cold or hard and soft we cannot perceive; what we perceive must have a degree of the sensible quality lying beyond the neutral point. This implies that the sense itself is a ‘mean’ between any two opposite qualities which determine the field of that sense. It is to this that it owes its power of discerning the objects in that field.
(5)
What is ‘in the middle’ is fitted to discern; relatively to either extreme it can put itself in the place of the other. As what is to perceive
both
white and black must, to begin with, be actually neither but potentially either (and so with all the other sense-organs), so the organ of touch must be neither hot nor cold.

Further, as in a sense sight had
⁴²
for its object both what was visible and what was invisible (and there was a parallel truth about all the other senses discussed),
⁴³
(10)
so touch has for its object both what is tangible and what is intangible. Here by ‘intangible’ is meant (
a
) what like air possesses some quality of tangible things in a very slight degree and (
b
) what possesses it in an excessive degree, as destructive things do.

We have now given an outline account of each of the several senses.
(15)

12
     The following results applying to any and every sense may now be formulated.

(A) By a ‘sense’ is meant what has the power of receiving into itself the sensible forms of things without the matter. This must be conceived of as taking place in the way in which a piece of wax takes on the impress of a signet-ring without the iron or gold; we say that what produces the impression is a signet of bronze or gold,
(20)
but its particular metallic constitution makes no difference: in a similar way the sense is affected by what is coloured or flavoured or sounding, but it is indifferent what in each case the
substance
is; what alone matters is what
quality
it has, i. e. in what
ratio
its constituents are combined.

(B) By ‘an organ of sense’ is meant that in which ultimately such a power is seated.

The sense and its organ are the same in fact,
(25)
but their essence is not the same. What perceives is, of course, a spatial magnitude, but we must not admit that either the having the power to perceive or the sense itself is a magnitude; what they are is a certain ratio or power
in
a magnitude. This enables us to explain why objects of sense which possess one of two opposite sensible qualities in a degree largely in excess of the other opposite destroy the organs of sense; if the movement set up by an object is too strong for the organ,
(30)
the equipoise of contrary qualities in the organ, which just
is
its sensory power, is disturbed; it is precisely as concord and tone are destroyed by too violently twanging the strings of a lyre. This explains also why plants cannot perceive, in spite of their having a portion of soul in them and obviously being affected by tangible objects themselves; for undoubtedly their temperature can be lowered or raised.
[424b]
The explanation is that they have no mean of contrary qualities, and so no principle in them capable of taking on the forms of sensible objects without their matter; in the case of plants the affection is an affection by form-and-matter together. The problem might be raised: Can what cannot smell be said to be affected by smells or what cannot see by colours,
(5)
and so on? It might be said that a smell is just what can be smelt, and if it produces any effect it can only be so as to make something smell it, and it might be argued that what cannot smell cannot be affected by smells and further that what can smell can be affected by it only in so far as it has in it the power to smell (similarly with the proper objects of all the other senses). Indeed that this
is
so is made quite evident as follows. Light or darkness,
(10)
sounds and smells leave
bodies
quite unaffected; what does affect bodies is not these but the bodies which are their vehicles, e. g. what splits the
trunk of a tree is not the sound of the thunder but the air which accompanies thunder. Yes, but, it may be objected, bodies are affected by what is tangible and by flavours. If not, by what are things that are without soul affected, i. e. altered in quality? Must we not, then, admit that the objects of the other senses also may affect them? Is not the true account this, that all bodies
are
capable of being affected by smells and sounds, but that some on being acted upon,
(15)
having no boundaries of their own, disintegrate, as in the instance of air, which does become odorous, showing that
some
effect is produced on it by what is odorous? But smelling is more than such an affection by what is odorous—
what
more? Is not the answer that, while the air owing to the momentary duration of the action upon it of what is odorous does itself become perceptible to the sense of smell, smelling is an
observing
of the result produced?