Aristotle

by Various Works [lit]

  repeat what we said before, if the medium for touch were a membrane

  separating us from the object without our observing its existence,

  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, 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, 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.

  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. The organ for the perception of these is that of

  touch-that part of the body in which primarily the sense of touch

  resides. 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. 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. 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 for its object both what was

  visible and what was invisible (and there was a parallel truth about

  all the other senses discussed), 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.

  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, 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, 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, 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. 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, 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, 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,

  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?

  Book III
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  1

  THAT there is no sixth sense in addition to the five

  enumerated-sight, hearing, smell, taste, touch-may be established by

  the following considerations:

  If we have actually sensation of everything of which touch can

  give us sensation (for all the qualities of the tangible qua

  tangible are perceived by us through touch); and if absence of a sense

  necessarily involves absence of a sense-organ; and if (1) all

  objects that we perceive by immediate contact with them are

  perceptible by touch, which sense we actually possess, and (2) all

  objects that we perceive through media, i.e. without immediate

  contact, are perceptible by or through the simple elements, e.g. air

  and water (and this is so arranged that (a) if more than one kind of

  sensible object is perceivable through a single medium, the

  possessor of a sense-organ homogeneous with that medium has the

  power of perceiving both kinds of objects; for example, if the

  sense-organ is made of air, and air is a medium both for sound and for

  colour; and that (b) if more than one medium can transmit the same

  kind of sensible objects, as e.g. water as well as air can transmit

  colour, both being transparent, then the possessor of either alone

  will be able to perceive the kind of objects transmissible through

  both); and if of the simple elements two only, air and water, go to

  form sense-organs (for the pupil is made of water, the organ of

  hearing is made of air, and the organ of smell of one or other of

  these two, while fire is found either in none or in all-warmth being

  an essential condition of all sensibility-and earth either in none or,

  if anywhere, specially mingled with the components of the organ of

  touch; wherefore it would remain that there can be no sense-organ

  formed of anything except water and air); and if these sense-organs

  are actually found in certain animals;-then all the possible senses

  are possessed by those animals that are not imperfect or mutilated

  (for even the mole is observed to have eyes beneath its skin); so

  that, if there is no fifth element and no property other than those

  which belong to the four elements of our world, no sense can be

  wanting to such animals.

  Further, there cannot be a special sense-organ for the common

  sensibles either, i.e. the objects which we perceive incidentally

  through this or that special sense, e.g. movement, rest, figure,

  magnitude, number, unity; for all these we perceive by movement,

  e.g. magnitude by movement, and therefore also figure (for figure is a

  species of magnitude), what is at rest by the absence of movement:

  number is perceived by the negation of continuity, and by the

  special sensibles; for each sense perceives one class of sensible

  objects. So that it is clearly impossible that there should be a

  special sense for any one of the common sensibles, e.g. movement; for,

  if that were so, our perception of it would be exactly parallel to our

  present perception of what is sweet by vision. That is so because we

  have a sense for each of the two qualities, in virtue of which when

  they happen to meet in one sensible object we are aware of both

  contemporaneously. If it were not like this our perception of the

  common qualities would always be incidental, i.e. as is the perception

  of Cleon's son, where we perceive him not as Cleon's son but as white,

  and the white thing which we really perceive happens to be Cleon's

  son.

  But in the case of the common sensibles there is already in us a

  general sensibility which enables us to perceive them directly;

  there is therefore no special sense required for their perception:

  if there were, our perception of them would have been exactly like

  what has been above described.

  The senses perceive each other's special objects incidentally; not

  because the percipient sense is this or that special sense, but

  because all form a unity: this incidental perception takes place

  whenever sense is directed at one and the same moment to two disparate

  qualities in one and the same object, e.g. to the bitterness and the

  yellowness of bile, the assertion of the identity of both cannot be

  the act of either of the senses; hence the illusion of sense, e.g. the

  belief that if a thing is yellow it is bile.

  It might be asked why we have more senses than one. Is it to prevent

  a failure to apprehend the common sensibles, e.g. movement, magnitude,

  and number, which go along with the special sensibles? Had we no sense

  but sight, and that sense no object but white, they would have

  tended to escape our notice and everything would have merged for us

  into an indistinguishable identity because of the concomitance of

  colour and magnitude. As it is, the fact that the common sensibles are

  given in the objects of more than one sense reveals their

  distinction from each and all of the special sensibles.

  2

  Since it is through sense that we are aware that we are seeing or

  hearing, it must be either by sight that we are aware of seeing, or by

  some sense other than sight. But the sense that gives us this new

  sensation must perceive both sight and its object, viz. colour: so

  that either (1) there will be two senses both percipient of the same

  sensible object, or (2) the sense must be percipient of itself.

  Further, even if the sense which perceives sight were different from

  sight, we must either fall into an infinite regress, or we must

  somewhere assume a sense which is aware of itself. If so, we ought

  to do this in the first case.

  This presents a difficulty: if to perceive by sight is just to

  see, and what is seen is colour (or the coloured), then if we are to

  see that which sees, that which sees originally must be coloured. It

  is clear therefore that 'to perceive by sight' has more than one

  meaning; for even when we are not seeing, it is by sight that we

  discriminate darkness from light, though not in the same way as we

  distinguish one colour from another. Further, in a sense even that

  which sees is coloured; for in each case the sense-organ is capable of

  receiving the sensible object without its matter. That is why even

  when the sensible objects are gone the sensings and imaginings

  continue to exist in the sense-organs.

  The activity of the sensible object and that of the percipient sense

  is one and the same activity, and yet the distinction between their

  being remains. Take as illustration actual sound and actual hearing: a

  man may have hearing and yet not be hearing, and that which has a

  sound is not always sounding. But when that which can hear is actively

  hearing and which can sound is sounding, then the actual hearing and

  the actual sound are merged in one (these one might call

  respectively hearkening and sounding).

  If it is true that the movement, both the acting and the being acted

  upon, is to be found in that which is acted upon, both the sound and

  the hearing so far as it is actual must be found in that which has the

  faculty of hearing; for it is in the passive factor that the actualityr />
  of the active or motive factor is realized; that is why that which

  causes movement may be at rest. Now the actuality of that which can

  sound is just sound or sounding, and the actuality of that which can

  hear is hearing or hearkening; 'sound' and 'hearing' are both

  ambiguous. The same account applies to the other senses and their

  objects. For as the-acting-and-being-acted-upon is to be found in

  the passive, not in the active factor, so also the actuality of the

  sensible object and that of the sensitive subject are both realized in

  the latter. But while in some cases each aspect of the total actuality

  has a distinct name, e.g. sounding and hearkening, in some one or

  other is nameless, e.g. the actuality of sight is called seeing, but

  the actuality of colour has no name: the actuality of the faculty of

  taste is called tasting, but the actuality of flavour has no name.

  Since the actualities of the sensible object and of the sensitive

  faculty are one actuality in spite of the difference between their

  modes of being, actual hearing and actual sounding appear and

  disappear from existence at one and the same moment, and so actual

  savour and actual tasting, c., while as potentialities one of them

  may exist without the other. The earlier students of nature were

  mistaken in their view that without sight there was no white or black,

  without taste no savour. This statement of theirs is partly true,

  partly false: 'sense' and 'the sensible object' are ambiguous terms,

  i.e. may denote either potentialities or actualities: the statement is

  true of the latter, false of the former. This ambiguity they wholly

  failed to notice.

  If voice always implies a concord, and if the voice and the

  hearing of it are in one sense one and the same, and if concord always

  implies a ratio, hearing as well as what is heard must be a ratio.

  That is why the excess of either the sharp or the flat destroys the

  hearing. (So also in the case of savours excess destroys the sense

  of taste, and in the case of colours excessive brightness or