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The Works of Aristotle. Translated Into English Under the Editorship of J.A. Smith, W.D. Ross. Oxford, 1908.

====== Aristotle: Sense and Sensibilia ======

===== SECTION 1 =====


==== Part 1 ====
 

Having now definitely considered the soul, by itself, and its several
faculties, we must next make a survey of animals and all living things,
in order to ascertain what functions are peculiar, and what functions
are common, to them. What has been already determined respecting the
soul [sc. by itself] must be assumed throughout. The remaining parts
[sc. the attributes of soul and body conjointly] of our subject must
be now dealt with, and we may begin with those that come first.

The most important attributes of animals, whether common to all or
peculiar to some, are, manifestly, attributes of soul and body in
conjunction, e.g. sensation, memory, passion, appetite and desire
in general, and, in addition pleasure and pain. For these may, in
fact, be said to belong to all animals. But there are, besides these,
certain other attributes, of which some are common to all living things,
while others are peculiar to certain species of animals. The most
important of these may be summed up in four pairs, viz. waking and
sleeping, youth and old age, inhalation and exhalation, life and death.
We must endeavour to arrive at a scientific conception of these, determining
their respective natures, and the causes of their occurrence.

But it behoves the Physical Philosopher to obtain also a clear view
of the first principles of health and disease, inasmuch as neither
health nor disease can exist in lifeless things. Indeed we may say
of most physical inquirers, and of those physicians who study their
art philosophically, that while the former complete their works with
a disquisition on medicine, the latter usually base their medical
theories on principles derived from Physics. 

That all the attributes above enumerated belong to soul and body in
conjunction, is obvious; for they all either imply sensation as a
concomitant, or have it as their medium. Some are either affections
or states of sensation, others, means of defending and safe-guarding
it, while others, again, involve its destruction or negation. Now
it is clear, alike by reasoning and observation, that sensation is
generated in the soul through the medium of the body. 

We have already, in our treatise On the Soul, explained the nature
of sensation and the act of perceiving by sense, and the reason why
this affection belongs to animals. Sensation must, indeed, be attributed
to all animals as such, for by its presence or absence we distinguish
essentially between what is and what is not an animal. 

But coming now to the special senses severally, we may say that touch
and taste necessarily appertain to all animals, touch, for the reason
given in On the Soul, and taste, because of nutrition. It is by taste
that one distinguishes in food the pleasant from the unpleasant, so
as to flee from the latter and pursue the former: and savour in general
is an affection of nutrient matter. 

The senses which operate through external media, viz. smelling, hearing,
seeing, are found in all animals which possess the faculty of locomotion.
To all that possess them they are a means of preservation; their final
cause being that such creatures may, guided by antecedent perception,
both pursue their food, and shun things that are bad or destructive.
But in animals which have also intelligence they serve for the attainment
of a higher perfection. They bring in tidings of many distinctive
qualities of things, from which the knowledge of truth, speculative
and practical, is generated in the soul. 

Of the two last mentioned, seeing, regarded as a supply for the primary
wants of life, and in its direct effects, is the superior sense; but
for developing intelligence, and in its indirect consequences, hearing
takes the precedence. The faculty of seeing, thanks to the fact that
all bodies are coloured, brings tidings of multitudes of distinctive
qualities of all sorts; whence it is through this sense especially
that we perceive the common sensibles, viz. figure, magnitude, motion,
number: while hearing announces only the distinctive qualities of
sound, and, to some few animals, those also of voice. indirectly,
however, it is hearing that contributes most to the growth of intelligence.
For rational discourse is a cause of instruction in virtue of its
being audible, which it is, not directly, but indirectly; since it
is composed of words, and each word is a thought-symbol. Accordingly,
of persons destitute from birth of either sense, the blind are more
intelligent than the deaf and dumb. 

==== Part 2 ====


Of the distinctive potency of each of the faculties of sense enough
has been said already. 

But as to the nature of the sensory organs, or parts of the body in
which each of the senses is naturally implanted, inquirers now usually
take as their guide the fundamental elements of bodies. Not, however,
finding it easy to coordinate five senses with four elements, they
are at a loss respecting the fifth sense. But they hold the organ
of sight to consist of fire, being prompted to this view by a certain
sensory affection of whose true cause they are ignorant. This is that,
when the eye is pressed or moved, fire appears to flash from it. This
naturally takes place in darkness, or when the eyelids are closed,
for then, too, darkness is produced. 

This theory, however, solves one question only to raise another; for,
unless on the hypothesis that a person who is in his full senses can
see an object of vision without being aware of it, the eye must on
this theory see itself. But then why does the above affection not
occur also when the eye is at rest? The true explanation of this affection,
which will contain the answer to our question, and account for the
current notion that the eye consists of fire, must be determined in
the following way: Things which are smooth have the natural property
of shining in darkness, without, however, producing light. Now, the
part of the eye called 'the black', i.e. its central part, is manifestly
smooth. The phenomenon of the flash occurs only when the eye is moved,
because only then could it possibly occur that the same one object
should become as it were two. The rapidity of the movement has the
effect of making that which sees and that which is seen seem different
from one another. Hence the phenomenon does not occur unless the motion
is rapid and takes place in darkness. For it is in the dark that that
which is smooth, e.g. the heads of certain fishes, and the sepia of
the cuttle-fish, naturally shines, and, when the movement of the eye
is slow, it is impossible that that which sees and that which is seen
should appear to be simultaneously two and one. But, in fact, the
eye sees itself in the above phenomenon merely as it does so in ordinary
optical reflexion. 

If the visual organ proper really were fire, which is the doctrine
of Empedocles, a doctrine taught also in the Timaeus, and if vision
were the result of light issuing from the eye as from a lantern, why
should the eye not have had the power of seeing even in the dark?
It is totally idle to say, as the Timaeus does, that the visual ray
coming forth in the darkness is quenched. What is the meaning of this
'quenching' of light? That which, like a fire of coals or an ordinary
flame, is hot and dry is, indeed, quenched by the moist or cold; but
heat and dryness are evidently not attributes of light. Or if they
are attributes of it, but belong to it in a degree so slight as to
be imperceptible to us, we should have expected that in the daytime
the light of the sun should be quenched when rain falls, and that
darkness should prevail in frosty weather. Flame, for example, and
ignited bodies are subject to such extinction, but experience shows
that nothing of this sort happens to the sunlight. 

Empedocles at times seems to hold that vision is to be explained as
above stated by light issuing forth from the eye, e.g. in the following
passage:- 

As when one who purposes going abroad prepares a lantern,

A gleam of fire blazing through the stormy night, 
Adjusting thereto, to screen it from all sorts of winds,

transparent sides, 
Which scatter the breath of the winds as they blow, 
While, out through them leaping, the fire, 
i.e. all the more subtile part of this, 
Shines along his threshold old incessant beams: 
So [Divine love] embedded the round "lens", [viz.] 
the primaeval fire fenced within the membranes, 
In [its own] delicate tissues; 
And these fended off the deep surrounding flood, 
While leaping forth the fire, i.e. all its more subtile part-.

Sometimes he accounts for vision thus, but at other times he explains
it by emanations from the visible objects. 

Democritus, on the other hand, is right in his opinion that the eye
is of water; not, however, when he goes on to explain seeing as mere
mirroring. The mirroring that takes place in an eye is due to the
fact that the eye is smooth, and it really has its seat not in the
eye which is seen, but in that which sees. For the case is merely
one of reflexion. But it would seem that even in his time there was
no scientific knowledge of the general subject of the formation of
images and the phenomena of reflexion. It is strange too, that it
never occurred to him to ask why, if his theory be true, the eye alone
sees, while none of the other things in which images are reflected
do so. 

True, then, the visual organ proper is composed of water, yet vision
appertains to it not because it is so composed, but because it is
translucent- a property common alike to water and to air. But water
is more easily confined and more easily condensed than air; wherefore
it is that the pupil, i.e. the eye proper, consists of water. That
it does so is proved by facts of actual experience. The substance
which flows from eyes when decomposing is seen to be water, and this
in undeveloped embryos is remarkably cold and glistening. In sanguineous
animals the white of the eye is fat and oily, in order that the moisture
of the eye may be proof against freezing. Wherefore the eye is of
all parts of the body the least sensitive to cold: no one ever feels
cold in the part sheltered by the eyelids. The eyes of bloodless animals
are covered with a hard scale which gives them similar protection.

It is, to state the matter generally, an irrational notion that the
eye should see in virtue of something issuing from it; that the visual
ray should extend itself all the way to the stars, or else go out
merely to a certain point, and there coalesce, as some say, with rays
which proceed from the object. It would be better to suppose this
coalescence to take place in the fundament of the eye itself. But
even this would be mere trifling. For what is meant by the 'coalescence'
of light with light? Or how is it possible? Coalescence does not occur
between any two things taken at random. And how could the light within
the eye coalesce with that outside it? For the environing membrane
comes between them. 

That without light vision is impossible has been stated elsewhere;
but, whether the medium between the eye and its objects is air or
light, vision is caused by a process through this medium.

Accordingly, that the inner part of the eye consists of water is easily
intelligible, water being translucent. 

Now, as vision outwardly is impossible without [extra-organic] light,
so also it is impossible inwardly [without light within the organ].
There must, therefore, be some translucent medium within the eye,
and, as this is not air, it must be water. The soul or its perceptive
part is not situated at the external surface of the eye, but obviously
somewhere within: whence the necessity of the interior of the eye
being translucent, i.e. capable of admitting light. And that it is
so is plain from actual occurrences. It is matter of experience that
soldiers wounded in battle by a sword slash on the temple, so inflicted
as to sever the passages of [i.e. inward from] the eye, feel a sudden
onset of darkness, as if a lamp had gone out; because what is called
the pupil, i.e. the translucent, which is a sort of inner lamp, is
then cut off [from its connexion with the soul]. 

Hence, if the facts be at all as here stated, it is clear that- if
one should explain the nature of the sensory organs in this way, i.e.
by correlating each of them with one of the four elements,- we must
conceive that the part of the eye immediately concerned in vision
consists of water, that the part immediately concerned in the perception
of sound consists of air, and that the sense of smell consists of
fire. (I say the sense of smell, not the organ.) For the organ of
smell is only potentially that which the sense of smell, as realized,
is actually; since the object of sense is what causes the actualization
of each sense, so that it (the sense) must (at the instant of actualization)
be (actually) that which before (the moment of actualization) it was
potentially. Now, odour is a smoke-like evaporation, and smoke-like
evaporation arises from fire. This also helps us to understand why
the olfactory organ has its proper seat in the environment of the
brain, for cold matter is potentially hot. In the same way must the
genesis of the eye be explained. Its structure is an offshoot from
the brain, because the latter is the moistest and coldest of all the
bodily parts. 

The organ of touch proper consists of earth, and the faculty of taste
is a particular form of touch. This explains why the sensory organ
of both touch and taste is closely related to the heart. For the heart
as being the hottest of all the bodily parts, is the counterpoise
of the brain. 

This then is the way in which the characteristics of the bodily organs
of sense must be determined. 

==== Part 3 ====


Of the sensibles corresponding to each sensory organ, viz. colour,
sound, odour, savour, touch, we have treated in On the Soul in general
terms, having there determined what their function is, and what is
implied in their becoming actualized in relation to their respective
organs. We must next consider what account we are to give of any one
of them; what, for example, we should say colour is, or sound, or
odour, or savour; and so also respecting [the object of] touch. We
begin with colour. 

Now, each of them may be spoken of from two points of view, i.e. either
as actual or as potential. We have in On the Soul explained in what
sense the colour, or sound, regarded as actualized [for sensation]
is the same as, and in what sense it is different from, the correlative
sensation, the actual seeing or hearing. The point of our present
discussion is, therefore, to determine what each sensible object must
be in itself, in order to be perceived as it is in actual consciousness.

We have already in On the Soul stated of Light that it is the colour
of the Translucent, [being so related to it] incidentally; for whenever
a fiery element is in a translucent medium presence there is Light;
while the privation of it is Darkness. But the 'Translucent', as we
call it, is not something peculiar to air, or water, or any other
of the bodies usually called translucent, but is a common 'nature'
and power, capable of no separate existence of its own, but residing
in these, and subsisting likewise in all other bodies in a greater
or less degree. As the bodies in which it subsists must have some
extreme bounding surface, so too must this. Here, then, we may say
that Light is a 'nature' inhering in the Translucent when the latter
is without determinate boundary. But it is manifest that, when the
Translucent is in determinate bodies, its bounding extreme must be
something real; and that colour is just this 'something' we are plainly
taught by facts-colour being actually either at the external limit,
or being itself that limit, in bodies. Hence it was that the Pythagoreans
named the superficies of a body its 'hue', for 'hue', indeed, lies
at the limit of the body; but the limit of the body; is not a real
thing; rather we must suppose that the same natural substance which,
externally, is the vehicle of colour exists [as such a possible vehicle]
also in the interior of the body. 

Air and water, too [i.e. as well as determinately bounded bodies]
are seen to possess colour; for their brightness is of the nature
of colour. But the colour which air or sea presents, since the body
in which it resides is not determinately bounded, is not the same
when one approaches and views it close by as it is when one regards
it from a distance; whereas in determinate bodies the colour presented
is definitely fixed, unless, indeed, when the atmospheric environment
causes it to change. Hence it is clear that that in them which is
susceptible of colour is in both cases the same. It is therefore the
Translucent, according to the degree to which it subsists in bodies
(and it does so in all more or less), that causes them to partake
of colour. But since the colour is at the extremity of the body, it
must be at the extremity of the Translucent in the body. Whence it
follows that we may define colour as the limit of the Translucent
in determinately bounded body. For whether we consider the special
class of bodies called translucent, as water and such others, or determinate
bodies, which appear to possess a fixed colour of their own, it is
at the exterior bounding surface that all alike exhibit their colour.

Now, that which when present in air produces light may be present
also in the Translucent which pervades determinate bodies; or again,
it may not be present, but there may be a privation of it. Accordingly,
as in the case of air the one condition is light, the other darkness,
in the same way the colours White and Black are generated in determinate
bodies. 

We must now treat of the other colours, reviewing the several hypotheses
invented to explain their genesis. 

(1) It is conceivable that the White and the Black should be juxtaposed
in quantities so minute that [a particle of] either separately would
be invisible, though the joint product [of two particles, a black
and a white] would be visible; and that they should thus have the
other colours for resultants. Their product could, at all events,
appear neither white nor black; and, as it must have some colour,
and can have neither of these, this colour must be of a mixed character-
in fact, a species of colour different from either. Such, then, is
a possible way of conceiving the existence of a plurality of colours
besides the White and Black; and we may suppose that [of this 'plurality']
many are the result of a [numerical] ratio; for the blacks and whites
may be juxtaposed in the ratio of 3 to 2 or of 3 to 4, or in ratios
expressible by other numbers; while some may be juxtaposed according
to no numerically expressible ratio, but according to some relation
of excess or defect in which the blacks and whites involved would
be incommensurable quantities; and, accordingly, we may regard all
these colours [viz. all those based on numerical ratios] as analogous
to the sounds that enter into music, and suppose that those involving
simple numerical ratios, like the concords in music, may be those
generally regarded as most agreeable; as, for example, purple, crimson,
and some few such colours, their fewness being due to the same causes
which render the concords few. The other compound colours may be those
which are not based on numbers. Or it may be that, while all colours
whatever [except black and white] are based on numbers, some are regular
in this respect, others irregular; and that the latter [though now
supposed to be all based on numbers], whenever they are not pure,
owe this character to a corresponding impurity in [the arrangement
of] their numerical ratios. This then is one conceivable hypothesis
to explain the genesis of intermediate colours. 

(2) Another is that the Black and White appear the one through the
medium of the other, giving an effect like that sometimes produced
by painters overlaying a less vivid upon a more vivid colour, as when
they desire to represent an object appearing under water or enveloped
in a haze, and like that produced by the sun, which in itself appears
white, but takes a crimson hue when beheld through a fog or a cloud
of smoke. On this hypothesis, too, a variety of colours may be conceived
to arise in the same way as that already described; for between those
at the surface and those underneath a definite ratio might sometimes
exist; in other cases they might stand in no determinate ratio. To
[introduce a theory of colour which would set all these hypotheses
aside, and] say with the ancients that colours are emanations, and
that the visibility of objects is due to such a cause, is absurd.
For they must, in any case, explain sense-perception through Touch;
so that it were better to say at once that visual perception is due
to a process set up by the perceived object in the medium between
this object and the sensory organ; due, that is, to contact [with
the medium affected,] not to emanations. 

If we accept the hypothesis of juxtaposition, we must assume not only
invisible magnitude, but also imperceptible time, in order that the
succession in the arrival of the stimulatory movements may be unperceived,
and that the compound colour seen may appear to be one, owing to its
successive parts seeming to present themselves at once. On the hypothesis
of superposition, however, no such assumption is needful: the stimulatory
process produced in the medium by the upper colour, when this is itself
unaffected, will be different in kind from that produced by it when
affected by the underlying colour. Hence it presents itself as a different
colour, i.e. as one which is neither white nor black. So that, if
it is impossible to suppose any magnitude to be invisible, and we
must assume that there is some distance from which every magnitude
is visible, this superposition theory, too [i.e. as well as No. 3
infra], might pass as a real theory of colour-mixture. Indeed, in
the previous case also there is no reason why, to persons at a distance
from the juxtaposed blacks and whites, some one colour should not
appear to present itself as a blend of both. [But it would not be
so on a nearer view], for it will be shown, in a discussion to be
undertaken later on, that there is no magnitude absolutely invisible.

(3) There is a mixture of bodies, however, not merely such as some
suppose, i.e. by juxtaposition of their minimal parts, which, owing
to [the weakness of our] sense, are imperceptible by us, but a mixture
by which they [i.e. the 'matter' of which they consist] are wholly
blent together by interpenetration, as we have described it in the
treatise on Mixture, where we dealt with this subject generally in
its most comprehensive aspect. For, on the supposition we are criticizing,
the only totals capable of being mixed are those which are divisible
into minimal parts, [e.g. genera into individuals] as men, horses,
or the [various kinds of] seeds. For of mankind as a whole the individual
man is such a least part; of horses [as an aggregate] the individual
horse. Hence by the juxtaposition of these we obtain a mixed total,
consisting [like a troop of cavalry] of both together; but we do not
say that by such a process any individual man has been mixed with
any individual horse. Not in this way, but by complete interpenetration
[of their matter], must we conceive those things to be mixed which
are not divisible into minima; and it is in the case of these that
natural mixture exhibits itself in its most perfect form. We have
explained already in our discourse 'On Mixture' how such mixture is
possible. This being the true nature of mixture, it is plain that
when bodies are mixed their colours also are necessarily mixed at
the same time; and [it is no less plain] that this is the real cause
determining the existence of a plurality of colours- not superposition
or juxtaposition. For when bodies are thus mixed, their resultant
colour presents itself as one and the same at all distances alike;
not varying as it is seen nearer or farther away. 

Colours will thus, too [as well as on the former hypotheses], be many
in number on account of the fact that the ingredients may be combined
with one another in a multitude of ratios; some will be based on determinate
numerical ratios, while others again will have as their basis a relation
of quantitative excess or defect not expressible in integers. And
all else that was said in reference to the colours, considered as
juxtaposed or superposed, may be said of them likewise when regarded
as mixed in the way just described. 

Why colours, as well as savours and sounds, consist of species determinate
[in themselves] and not infinite [in number] is a question which we
shall discuss hereafter. 

==== Part 4 ====

We have now explained what colour is, and the reason why there are
many colours; while before, in our work On the Soul, we explained
the nature of sound and voice. We have next to speak of Odour and
Savour, both of which are almost the same physical affection, although
they each have their being in different things. Savours, as a class,
display their nature more clearly to us than Odours, the cause of
which is that the olfactory sense of man is inferior in acuteness
to that of the lower animals, and is, when compared with our other
senses, the least perfect of Man's sense of Touch, on the contrary,
excels that of all other animals in fineness, and Taste is a modification
of Touch. 

Now the natural substance water per se tends to be tasteless. But
[since without water tasting is impossible] either (a) we must suppose
that water contains in itself [uniformly diffused through it] the
various kinds of savour, already formed, though in amounts so small
as to be imperceptible, which is the doctrine of Empedocles; or (b)
the water must be a sort of matter, qualified, as it were, to produce
germs of savours of all kinds, so that all kinds of savour are generated
from the water, though different kinds from its different parts, or
else (c) the water is in itself quite undifferentiated in respect
of savour [whether developed or undeveloped], but some agent, such
for example as one might conceive Heat or the Sun to be, is the efficient
cause of savour. 

(a) Of these three hypotheses, the falsity of that held by Empedocles
is only too evident. For we see that when pericarpal fruits are plucked
[from the tree] and exposed in the sun, or subjected to the action
of fire, their sapid juices are changed by the heat, which shows that
their qualities are not due to their drawing anything from the water
in the ground, but to a change which they undergo within the pericarp
itself; and we see, moreover, that these juices, when extracted and
allowed to lie, instead of sweet become by lapse of time harsh or
bitter, or acquire savours of any and every sort; and that, again,
by the process of boiling or fermentation they are made to assume
almost all kinds of new savours. 

(b) It is likewise impossible that water should be a material qualified
to generate all kinds of Savour germs [so that different savours should
arise out of different parts of the water]; for we see different kinds
of taste generated from the same water, having it as their nutriment.

(C) It remains, therefore, to suppose that the water is changed by
passively receiving some affection from an external agent. Now, it
is manifest that water does not contract the quality of sapidity from
the agency of Heat alone. For water is of all liquids the thinnest,
thinner even than oil itself, though oil, owing to its viscosity,
is more ductile than water, the latter being uncohesive in its particles;
whence water is more difficult than oil to hold in the hand without
spilling. But since perfectly pure water does not, when subjected
to the action of Heat, show any tendency to acquire consistency, we
must infer that some other agency than heat is the cause of sapidity.
For all savours [i.e. sapid liquors] exhibit a comparative consistency.
Heat is, however, a coagent in the matter. 

Now the sapid juices found in pericarpal fruits evidently exist also
in the earth. Hence many of the old natural philosophers assert that
water has qualities like those of the earth through which it flows,
a fact especially manifest in the case of saline springs, for salt
is a form of earth. Hence also when liquids are filtered through ashes,
a bitter substance, the taste they yield is bitter. There are many
wells, too, of which some are bitter, others acid, while others exhibit
other tastes of all kinds. 

As was to be anticipated, therefore, it is in the vegetable kingdom
that tastes occur in richest variety. For, like all things else, the
Moist, by nature's law, is affected only by its contrary; and this
contrary is the Dry. Thus we see why the Moist is affected by Fire,
which as a natural substance, is dry. Heat is, however, the essential
property of Fire, as Dryness is of Earth, according to what has been
said in our treatise on the elements. Fire and Earth, therefore, taken
absolutely as such, have no natural power to affect, or be affected
by, one another; nor have any other pair of substances. Any two things
can affect, or be affected by, one another only so far as contrariety
to the other resides in either of them. 

As, therefore, persons washing Colours or Savours in a liquid cause
the water in which they wash to acquire such a quality [as that of
the colour or savour], so nature, too, by washing the Dry and Earthy
in the Moist, and by filtering the latter, that is, moving it on by
the agency of heat through the dry and earthy, imparts to it a certain
quality. This affection, wrought by the aforesaid Dry in the Moist,
capable of transforming the sense of Taste from potentiality to actuality,
is Savour. Savour brings into actual exercise the perceptive faculty
which pre-existed only in potency. The activity of sense-perception
in general is analogous, not to the process of acquiring knowledge,
but to that of exercising knowledge already acquired. 

That Savours, either as a quality or as the privation of a quality,
belong not to every form of the Dry but to the Nutrient, we shall
see by considering that neither the Dry without the Moist, nor the
Moist without the Dry, is nutrient. For no single element, but only
composite substance, constitutes nutriment for animals. Now, among
the perceptible elements of the food which animals assimilate, the
tangible are the efficient causes of growth and decay; it is qua hot
or cold that the food assimilated causes these; for the heat or cold
is the direct cause of growth or decay. It is qua gustable, however,
that the assimilated food supplies nutrition. For all organisms are
nourished by the Sweet [i.e. the 'gustable' proper], either by itself
or in combination with other savours. Of this we must speak with more
precise detail in our work on Generation: for the present we need
touch upon it only so far as our subject here requires. Heat causes
growth, and fits the food-stuff for alimentation; it attracts [into
the organic system] that which is light [viz. the sweet], while the
salt and bitter it rejects because of their heaviness. In fact, whatever
effects external heat produces in external bodies, the same are produced
by their internal heat in animal and vegetable organisms. Hence it
is [i.e. by the agency of heat as described] that nourishment is effected
by the sweet. The other savours are introduced into and blended in
food [naturally] on a principle analogous to that on which the saline
or the acid is used artificially, i.e. for seasoning. These latter
are used because they counteract the tendency of the sweet to be too
nutrient, and to float on the stomach. 

As the intermediate colours arise from the mixture of white and black,
so the intermediate savours arise from the Sweet and Bitter; and these
savours, too, severally involve either a definite ratio, or else an
indefinite relation of degree, between their components, either having
certain integral numbers at the basis of their mixture, and, consequently,
of their stimulative effect, or else being mixed in proportions not
arithmetically expressible. The tastes which give pleasure in their
combination are those which have their components joined in a definite
ratio. 

The sweet taste alone is Rich, [therefore the latter may be regarded
as a variety of the former], while [so far as both imply privation
of the Sweet] the Saline is fairly identical with the Bitter. Between
the extremes of sweet and bitter come the Harsh, the Pungent, the
Astringent, and the Acid. Savours and Colours, it will be observed,
contain respectively about the same number of species. For there are
seven species of each, if, as is reasonable, we regard Dun [or Grey]
as a variety of Black (for the alternative is that Yellow should be
classed with White, as Rich with Sweet); while [the irreducible colours,
viz.] Crimson, Violet, leek-Green, and deep Blue, come between White
and Black, and from these all others are derived by mixture.

Again, as Black is a privation of White in the Translucent, so Saline
or Bitter is a privation of Sweet in the Nutrient Moist. This explains
why the ash of all burnt things is bitter; for the potable [sc. the
sweet] moisture has been exuded from them. 

Democritus and most of the natural philosophers who treat of sense-perception
proceed quite irrationally, for they represent all objects of sense
as objects of Touch. Yet, if this is really so, it clearly follows
that each of the other senses is a mode of Touch; but one can see
at a glance that this is impossible. 

Again, they treat the percepts common to all senses as proper to one.
For [the qualities by which they explain taste viz.] Magnitude and
Figure, Roughness and Smoothness, and, moreover, the Sharpness and
Bluntness found in solid bodies, are percepts common to all the senses,
or if not to all, at least to Sight and Touch. This explains why it
is that the senses are liable to err regarding them, while no such
error arises respecting their proper sensibles; e.g. the sense of
Seeing is not deceived as to Colour, nor is that of Hearing as to
Sound. 

On the other hand, they reduce the proper to common sensibles, as
Democritus does with White and Black; for he asserts that the latter
is [a mode of the] rough, and the former [a mode of the] smooth, while
he reduces Savours to the atomic figures. Yet surely no one sense,
or, if any, the sense of Sight rather than any other, can discern
the common sensibles. But if we suppose that the sense of Taste is
better able to do so, then- since to discern the smallest objects
in each kind is what marks the acutest sense-Taste should have been
the sense which best perceived the common sensibles generally, and
showed the most perfect power of discerning figures in general.

Again, all the sensibles involve contrariety; e.g. in Colour White
is contrary to Black, and in Savours Bitter is contrary to Sweet;
but no one figure is reckoned as contrary to any other figure. Else,
to which of the possible polygonal figures [to which Democritus reduces
Bitter] is the spherical figure [to which he reduces Sweet] contrary?

Again, since figures are infinite in number, savours also should be
infinite; [the possible rejoinder- 'that they are so, only that some
are not perceived'- cannot be sustained] for why should one savour
be perceived, and another not? 

This completes our discussion of the object of Taste, i.e. Savour;
for the other affections of Savours are examined in their proper place
in connection with the natural history of Plants. 

----------------------------------------------------------------------

===== SECTION 2 =====

==== Part 5 ====
 

Our conception of the nature of Odours must be analogous to that
of Savours; inasmuch as the Sapid Dry effects in air and water alike,
but in a different province of sense, precisely what the Dry effects
in the Moist of water only. We customarily predicate Translucency
of both air and water in common; but it is not qua translucent that
either is a vehicle of odour, but qua possessed of a power of washing
or rinsing [and so imbibing] the Sapid Dryness. 

For the object of Smell exists not in air only: it also exists in
water. This is proved by the case of fishes and testacea, which are
seen to possess the faculty of smell, although water contains no air
(for whenever air is generated within water it rises to the surface),
and these creatures do not respire. Hence, if one were to assume that
air and water are both moist, it would follow that Odour is the natural
substance consisting of the Sapid Dry diffused in the Moist, and whatever
is of this kind would be an object of Smell. 

That the property of odorousness is based upon the Sapid may be seen
by comparing the things which possess with those which do not possess
odour. The elements, viz. Fire, Air, Earth, Water, are inodorous,
because both the dry and the moist among them are without sapidity,
unless some added ingredient produces it. This explains why sea-water
possesses odour, for [unlike 'elemental' water] it contains savour
and dryness. Salt, too, is more odorous than natron, as the oil which
exudes from the former proves, for natron is allied to ['elemental']
earth more nearly than salt. Again, a stone is inodorous, just because
it is tasteless, while, on the contrary, wood is odorous, because
it is sapid. The kinds of wood, too, which contain more ['elemental']
water are less odorous than others. Moreover, to take the case of
metals, gold is inodorous because it is without taste, but bronze
and iron are odorous; and when the [sapid] moisture has been burnt
out of them, their slag is, in all cases, less odorous the metals
[than the metals themselves]. Silver and tin are more odorous than
the one class of metals, less so than the other, inasmuch as they
are water [to a greater degree than the former, to a less degree than
the latter]. 

Some writers look upon Fumid exhalation, which is a compound of Earth
and Air, as the essence of Odour. [Indeed all are inclined to rush
to this theory of Odour.] Heraclitus implied his adherence to it when
he declared that if all existing things were turned into Smoke, the
nose would be the organ to discern them with. All writers incline
to refer odour to this cause [sc. exhalation of some sort], but some
regard it as aqueous, others as fumid, exhalation; while others, again,
hold it to be either. Aqueous exhalation is merely a form of moisture,
but fumid exhalation is, as already remarked, composed of Air and
Earth. The former when condensed turns into water; the latter, in
a particular species of earth. Now, it is unlikely that odour is either
of these. For vaporous exhalation consists of mere water [which, being
tasteless, is inodorous]; and fumid exhalation cannot occur in water
at all, though, as has been before stated, aquatic creatures also
have the sense of smell. 

Again, the exhalation theory of odour is analogous to the theory of
emanations. If, therefore, the latter is untenable, so, too, is the
former. 

It is clearly conceivable that the Moist, whether in air (for air,
too, is essentially moist) or in water, should imbibe the influence
of, and have effects wrought in it by, the Sapid Dryness. Moreover,
if the Dry produces in moist media, i.e. water and air, an effect
as of something washed out in them, it is manifest that odours must
be something analogous to savours. Nay, indeed, this analogy is, in
some instances, a fact [registered in language]; for odours as well
as savours are spoken of as pungent, sweet, harsh, astringent rich
[='savoury']; and one might regard fetid smells as analogous to bitter
tastes; which explains why the former are offensive to inhalation
as the latter are to deglutition. It is clear, therefore, that Odour
is in both water and air what Savour is in water alone. This explains
why coldness and freezing render Savours dull, and abolish odours
altogether; for cooling and freezing tend to annul the kinetic heat
which helps to fabricate sapidity. 

There are two species of the Odorous. For the statement of certain
writers that the odorous is not divisible into species is false; it
is so divisible. We must here define the sense in which these species
are to be admitted or denied. 

One class of odours, then, is that which runs parallel, as has been
observed, to savours: to odours of this class their pleasantness or
unpleasantness belongs incidentally. For owing to the fact that Savours
are qualities of nutrient matter, the odours connected with these
[e.g. those of a certain food] are agreeable as long as animals have
an appetite for the food, but they are not agreeable to them when
sated and no longer in want of it; nor are they agreeable, either,
to those animals that do not like the food itself which yields the
odours. Hence, as we observed, these odours are pleasant or unpleasant
incidentally, and the same reasoning explains why it is that they
are perceptible to all animals in common. 

The other class of odours consists of those agreeable in their essential
nature, e.g. those of flowers. For these do not in any degree stimulate
animals to food, nor do they contribute in any way to appetite; their
effect upon it, if any, is rather the opposite. For the verse of Strattis
ridiculing Euripides- 

Use not perfumery to flavour soup, contains a truth. 

Those who nowadays introduce such flavours into beverages deforce
our sense of pleasure by habituating us to them, until, from two distinct
kinds of sensations combined, pleasure arises as it might from one
simple kind. 

Of this species of odour man alone is sensible; the other, viz. that
correlated with Tastes, is, as has been said before, perceptible also
to the lower animals. And odours of the latter sort, since their pleasureableness
depends upon taste, are divided into as many species as there are
different tastes; but we cannot go on to say this of the former kind
of odour, since its nature is agreeable or disagreeable per se. The
reason why the perception of such odours is peculiar to man is found
in the characteristic state of man's brain. For his brain is naturally
cold, and the blood which it contains in its vessels is thin and pure
but easily cooled (whence it happens that the exhalation arising from
food, being cooled by the coldness of this region, produces unhealthy
rheums); therefore it is that odours of such a species have been generated
for human beings, as a safeguard to health. This is their sole function,
and that they perform it is evident. For food, whether dry or moist,
though sweet to taste, is often unwholesome; whereas the odour arising
from what is fragrant, that odour which is pleasant in its own right,
is, so to say, always beneficial to persons in any state of bodily
health whatever. 

For this reason, too, the perception of odour [in general] effected
through respiration, not in all animals, but in man and certain other
sanguineous animals, e.g. quadrupeds, and all that participate freely
in the natural substance air; because when odours, on account of the
lightness of the heat in them, mount to the brain, the health of this
region is thereby promoted. For odour, as a power, is naturally heat-giving.
Thus Nature has employed respiration for two purposes: primarily for
the relief thereby brought to the thorax, secondarily for the inhalation
of odour. For while an animal is inhaling,- odour moves in through
its nostrils, as it were 'from a side-entrance.' 

But the perception of the second class of odours above described [does
not belong to all animal, but] is confined to human beings, because
man's brain is, in proportion to his whole bulk, larger and moister
than the brain of any other animal. This is the reason of the further
fact that man alone, so to speak, among animals perceives and takes
pleasure in the odours of flowers and such things. For the heat and
stimulation set up by these odours are commensurate with the excess
of moisture and coldness in his cerebral region. On all the other
animals which have lungs, Nature has bestowed their due perception
of one of the two kinds of odour [i.e. that connected with nutrition]
through the act of respiration, guarding against the needless creation
of two organs of sense; for in the fact that they respire the other
animals have already sufficient provision for their perception of
the one species of odour only, as human beings have for their perception
of both. 

But that creatures which do not respire have the olfactory sense is
evident. For fishes, and all insects as a class, have, thanks to the
species of odour correlated with nutrition, a keen olfactory sense
of their proper food from a distance, even when they are very far
away from it; such is the case with bees, and also with the class
of small ants, which some denominate knipes. Among marine animals,
too, the murex and many other similar animals have an acute perception
of their food by its odour. 

It is not equally certain what the organ is whereby they so perceive.
This question, of the organ whereby they perceive odour, may well
cause a difficulty, if we assume that smelling takes place in animals
only while respiring (for that this is the fact is manifest in all
the animals which do respire), whereas none of those just mentioned
respires, and yet they have the sense of smell- unless, indeed, they
have some other sense not included in the ordinary five. This supposition
is, however, impossible. For any sense which perceives odour is a
sense of smell, and this they do perceive, though probably not in
the same way as creatures which respire, but when the latter are respiring
the current of breath removes something that is laid like a lid upon
the organ proper (which explains why they do not perceive odours when
not respiring); while in creatures which do not respire this is always
off: just as some animals have eyelids on their eyes, and when these
are not raised they cannot see, whereas hard-eyed animals have no
lids, and consequently do not need, besides eyes, an agency to raise
the lids, but see straightway [without intermission] from the actual
moment at which it is first possible for them to do so [i.e. from
the moment when an object first comes within their field of vision].

Consistently with what has been said above, not one of the lower animals
shows repugnance to the odour of things which are essentially ill-smelling,
unless one of the latter is positively pernicious. They are destroyed,
however, by these things, just as human beings are; i.e. as human
beings get headaches from, and are often asphyxiated by, the fumes
of charcoal, so the lower animals perish from the strong fumes of
brimstone and bituminous substances; and it is owing to experience
of such effects that they shun these. For the disagreeable odour in
itself they care nothing whatever (though the odours of many plants
are essentially disagreeable), unless, indeed, it has some effect
upon the taste of their food. 

The senses making up an odd number, and an odd number having always
a middle unit, the sense of smell occupies in itself as it were a
middle position between the tactual senses, i.e. Touch and Taste,
and those which perceive through a medium, i.e. Sight and Hearing.
Hence the object of smell, too, is an affection of nutrient substances
(which fall within the class of Tangibles), and is also an affection
of the audible and the visible; whence it is that creatures have the
sense of smell both in air and water. Accordingly, the object of smell
is something common to both of these provinces, i.e. it appertains
both to the tangible on the one hand, and on the other to the audible
and translucent. Hence the propriety of the figure by which it has
been described by us as an immersion or washing of dryness in the
Moist and Fluid. Such then must be our account of the sense in which
one is or is not entitled to speak of the odorous as having species.

The theory held by certain of the Pythagoreans, that some animals
are nourished by odours alone, is unsound. For, in the first place,
we see that food must be composite, since the bodies nourished by
it are not simple. This explains why waste matter is secreted from
food, either within the organisms, or, as in plants, outside them.
But since even water by itself alone, that is, when unmixed, will
not suffice for food- for anything which is to form a consistency
must be corporeal-, it is still much less conceivable that air should
be so corporealized [and thus fitted to be food]. But, besides this,
we see that all animals have a receptacle for food, from which, when
it has entered, the body absorbs it. Now, the organ which perceives
odour is in the head, and odour enters with the inhalation of the
breath; so that it goes to the respiratory region. It is plain, therefore,
that odour, qua odour, does not contribute to nutrition; that, however,
it is serviceable to health is equally plain, as well by immediate
perception as from the arguments above employed; so that odour is
in relation to general health what savour is in the province of nutrition
and in relation to the bodies nourished. 

This then must conclude our discussion of the several organs of sense-perception.

==== Part 6 ====


One might ask: if every body is infinitely divisible, are its sensible
qualities- Colour, Savour, Odour, Sound, Weight, Cold or Heat, [Heaviness
or] Lightness, Hardness or Softness-also infinitely divisible? Or,
is this impossible? 

[One might well ask this question], because each of them is productive
of sense-perception, since, in fact, all derive their name [of 'sensible
qualities'] from the very circumstance of their being able to stimulate
this. Hence, [if this is so] both our perception of them should likewise
be divisible to infinity, and every part of a body [however small]
should be a perceptible magnitude. For it is impossible, e.g. to see
a thing which is white but not of a certain magnitude. 

Since if it were not so, [if its sensible qualities were not divisible,
pari passu with body], we might conceive a body existing but having
no colour, or weight, or any such quality; accordingly not perceptible
at all. For these qualities are the objects of sense-perception. On
this supposition, every perceptible object should be regarded as composed
not of perceptible [but of imperceptible] parts. Yet it must [be really
composed of perceptible parts], since assuredly it does not consist
of mathematical [and therefore purely abstract and non-sensible] quantities.
Again, by what faculty should we discern and cognize these [hypothetical
real things without sensible qualities]? Is it by Reason? But they
are not objects of Reason; nor does reason apprehend objects in space,
except when it acts in conjunction with sense-perception. At the same
time, if this be the case [that there are magnitudes, physically real,
but without sensible quality], it seems to tell in favour of the atomistic
hypothesis; for thus, indeed, [by accepting this hypothesis], the
question [with which this chapter begins] might be solved [negatively].
But it is impossible [to accept this hypothesis]. Our views on the
subject of atoms are to be found in our treatise on Movement.

The solution of these questions will bring with it also the answer
to the question why the species of Colour, Taste, Sound, and other
sensible qualities are limited. For in all classes of things lying
between extremes the intermediates must be limited. But contraries
are extremes, and every object of sense-perception involves contrariety:
e.g. in Colour, White x Black; in Savour, Sweet x Bitter, and in all
the other sensibles also the contraries are extremes. Now, that which
is continuous is divisible into an infinite number of unequal parts,
but into a finite number of equal parts, while that which is not per
se continuous is divisible into species which are finite in number.
Since then, the several sensible qualities of things are to be reckoned
as species, while continuity always subsists in these, we must take
account of the difference between the Potential and the Actual. It
is owing to this difference that we do not [actually] see its ten-thousandth
part in a grain of millet, although sight has embraced the whole grain
within its scope; and it is owing to this, too, that the sound contained
in a quarter-tone escapes notice, and yet one hears the whole strain,
inasmuch as it is a continuum; but the interval between the extreme
sounds [that bound the quarter-tone] escapes the ear [being only potentially
audible, not actually]. So, in the case of other objects of sense,
extremely small constituents are unnoticed; because they are only
potentially not actually [perceptible e.g.] visible, unless when they
have been parted from the wholes. So the footlength too exists potentially
in the two-foot length, but actually only when it has been separated
from the whole. But objective increments so small as those above might
well, if separated from their totals, [instead of achieving 'actual'
exisistence] be dissolved in their environments, like a drop of sapid
moisture poured out into the sea. But even if this were not so [sc.
with the objective magnitude], still, since the [subjective] of sense-perception
is not perceptible in itself, nor capable of separate existence (since
it exists only potentially in the more distinctly perceivable whole
of sense-perception), so neither will it be possible to perceive [actually]
its correlatively small object [sc. its quantum of pathema or sensible
quality] when separated from the object-total. But yet this [small
object] is to be considered as perceptible: for it is both potentially
so already [i.e. even when alone], and destined to be actually so
when it has become part of an aggregate. Thus, therefore, we have
shown that some magnitudes and their sensible qualities escape notice,
and the reason why they do so, as well as the manner in which they
are still perceptible or not perceptible in such cases. Accordingly
then when these [minutely subdivided] sensibles have once again become
aggregated in a whole in such a manner, relatively to one another,
as to be perceptible actually, and not merely because they are in
the whole, but even apart from it, it follows necessarily [from what
has been already stated] that their sensible qualities, whether colours
or tastes or sounds, are limited in number. 

One might ask:- do the objects of sense-perception, or the movements
proceeding from them ([since movements there are,] in whichever of
the two ways [viz. by emanations or by stimulatory kinesis] sense-perception
takes place), when these are actualized for perception, always arrive
first at a spatial middle point [between the sense-organ and its object],
as Odour evidently does, and also Sound? For he who is nearer [to
the odorous object] perceives the Odour sooner [than who is farther
away], and the Sound of a stroke reaches us some time after it has
been struck. Is it thus also with an object seen, and with Light?
Empedocles, for example, says that the Light from the Sun arrives
first in the intervening space before it comes to the eye, or reaches
the Earth. This might plausibly seem to be the case. For whatever
is moved [in space], is moved from one place to another; hence there
must be a corresponding interval of time also in which it is moved
from the one place to the other. But any given time is divisible into
parts; so that we should assume a time when the sun's ray was not
as yet seen, but was still travelling in the middle space.

Now, even if it be true that the acts of 'hearing' and 'having heard',
and, generally, those of 'perceiving' and 'having perceived', form
co-instantaneous wholes, in other words, that acts of sense-perception
do not involve a process of becoming, but have their being none the
less without involving such a process; yet, just as, [in the case
of sound], though the stroke which causes the Sound has been already
struck, the Sound is not yet at the ear (and that this last is a fact
is further proved by the transformation which the letters [viz. the
consonants as heard] undergo [in the case of words spoken from a distance],
implying that the local movement [involved in Sound] takes place in
the space between [us and the speaker]; for the reason why [persons
addressed from a distance] do not succeed in catching the sense of
what is said is evidently that the air [sound wave] in moving towards
them has its form changed) [granting this, then, the question arises]:
is the same also true in the case of Colour and Light? For certainly
it is not true that the beholder sees, and the object is seen, in
virtue of some merely abstract relationship between them, such as
that between equals. For if it were so, there would be no need [as
there is] that either [the beholder or the thing beheld] should occupy
some particular place; since to the equalization of things their being
near to, or far from, one another makes no difference. 

Now this [travelling through successive positions in the medium] may
with good reason take place as regards Sound and Odour, for these,
like [their media] Air and Water, are continuous, but the movement
of both is divided into parts. This too is the ground of the fact
that the object which the person first in order of proximity hears
or smells is the same as that which each subsequent person perceives,
while yet it is not the same. 

Some, indeed, raise a question also on these very points; they declare
it impossible that one person should hear, or see, or smell, the same
object as another, urging the impossibility of several persons in
different places hearing or smelling [the same object], for the one
same thing would [thus] be divided from itself. The answer is that,
in perceiving the object which first set up the motion- e.g. a bell,
or frankincense, or fire- all perceive an object numerically one and
the same; while, of course, in the special object perceived they perceive
an object numerically different for each, though specifically the
same for all; and this, accordingly, explains how it is that many
persons together see, or smell, or hear [the same object]. These things
[the odour or sound proper] are not bodies, but an affection or process
of some kind (otherwise this [viz. simultaneous perception of the
one object by many] would not have been, as it is, a fact of experience)
though, on the other hand, they each imply a body [as their cause].

But [though sound and odour may travel,] with regard to Light the
case is different. For Light has its raison d'etre in the being [not
becoming] of something, but it is not a movement. And in general,
even in qualitative change the case is different from what it is in
local movement [both being different species of kinesis]. Local movements,
of course, arrive first at a point midway before reaching their goal
(and Sound, it is currently believed, is a movement of something locally
moved), but we cannot go on to assert this [arrival at a point midway]
like manner of things which undergo qualitative change. For this kind
of change may conceivably take place in a thing all at once, without
one half of it being changed before the other; e.g. it is conceivable
that water should be frozen simultaneously in every part. But still,
for all that, if the body which is heated or frozen is extensive,
each part of it successively is affected by the part contiguous, while
the part first changed in quality is so changed by the cause itself
which originates the change, and thus the change throughout the whole
need not take place coinstantaneously and all at once. Tasting would
have been as smelling now is, if we lived in a liquid medium, and
perceived [the sapid object] at a distance, before touching it.

Naturally, then, the parts of media between a sensory organ and its
object are not all affected at once- except in the case of Light [illumination]
for the reason above stated, and also in the case of seeing, for the
same reason; for Light is an efficient cause of seeing. 

==== Part 7 ====


Another question respecting sense-perception is as follows: assuming,
as is natural, that of two [simultaneous] sensory stimuli the stronger
always tends to extrude the weaker [from consciousness], is it conceivable
or not that one should be able to discern two objects coinstantaneously
in the same individual time? The above assumption explains why persons
do not perceive what is brought before their eyes, if they are at
the time deep in thought, or in a fright, or listening to some loud
noise. This assumption, then, must be made, and also the following:
that it is easier to discern each object of sense when in its simple
form than when an ingredient in a mixture; easier, for example, to
discern wine when neat than when blended, and so also honey, and [in
other provinces] a colour, or to discern the nete by itself alone,
than [when sounded with the hypate] in the octave; the reason being
that component elements tend to efface [the distinctive characteristics
of] one another. Such is the effect [on one another] of all ingredients
of which, when compounded, some one thing is formed. 

If, then, the greater stimulus tends to expel the less, it necessarily
follows that, when they concur, this greater should itself too be
less distinctly perceptible than if it were alone, since the less
by blending with it has removed some of its individuality, according
to our assumption that simple objects are in all cases more distinctly
perceptible. 

Now, if the two stimuli are equal but heterogeneous, no perception
of either will ensue; they will alike efface one another's characteristics.
But in such a case the perception of either stimulus in its simple
form is impossible. Hence either there will then be no sense-perception
at all, or there will be a perception compounded of both and differing
from either. The latter is what actually seems to result from ingredients
blended together, whatever may be the compound in which they are so
mixed. 

Since, then, from some concurrent [sensory stimuli] a resultant object
is produced, while from others no such resultant is produced, and
of the latter sort are those things which belong to different sense
provinces (for only those things are capable of mixture whose extremes
are contraries, and no one compound can be formed from, e.g. White
and Sharp, except indirectly, i.e. not as a concord is formed of Sharp
and Grave); there follows logically the impossibility of discerning
such concurrent stimuli coinstantaneously. For we must suppose that
the stimuli, when equal, tend alike to efface one another, since no
one [form of stimulus] results from them; while, if they are unequal,
the stronger alone is distinctly perceptible. 

Again, the soul would be more likely to perceive coinstantaneously,
with one and the same sensory act, two things in the same sensory
province, such as the Grave and the Sharp in sound; for the sensory
stimulation in this one province is more likely to be unitemporal
than that involving two different provinces, as Sight and Hearing.
But it is impossible to perceive two objects coinstantaneously in
the same sensory act unless they have been mixed, [when, however,
they are no longer two], for their amalgamation involves their becoming
one, and the sensory act related to one object is itself one, and
such act, when one, is, of course, coinstantaneous with itself. Hence,
when things are mixed we of necessity perceive them coinstantaneously:
for we perceive them by a perception actually one. For an object numerically
one means that which is perceived by a perception actually one, whereas
an object specifically one means that which is perceived by a sensory
act potentially one [i.e. by an energeia of the same sensuous faculty].
If then the actualized perception is one, it will declare its data
to be one object; they must, therefore, have been mixed. Accordingly,
when they have not been mixed, the actualized perceptions which perceive
them will be two; but [if so, their perception must be successive
not coinstantaneous, for] in one and the same faculty the perception
actualized at any single moment is necessarily one, only one stimulation
or exertion of a single faculty being possible at a single instant,
and in the case supposed here the faculty is one. It follows, therefore,
that we cannot conceive the possibility of perceiving two distinct
objects coinstantaneously with one and the same sense. 

But if it be thus impossible to perceive coinstantaneously two objects
in the same province of sense if they are really two, manifestly it
is still less conceivable that we should perceive coinstantaneously
objects in two different sensory provinces, as White and Sweet. For
it appears that when the Soul predicates numerical unity it does so
in virtue of nothing else than such coinstantaneous perception [of
one object, in one instant, by one energeia]: while it predicates
specific unity in virtue of [the unity of] the discriminating faculty
of sense together with [the unity of] the mode in which this operates.
What I mean, for example, is this; the same sense no doubt discerns
White and Black, [which are hence generically one] though specifically
different from one another, and so, too, a faculty of sense self-identical,
but different from the former, discerns Sweet and Bitter; but while
both these faculties differ from one another [and each from itself]
in their modes of discerning either of their respective contraries,
yet in perceiving the co-ordinates in each province they proceed in
manners analogous to one another; for instance, as Taste perceives
Sweet, so Sight perceives White; and as the latter perceives Black,
so the former perceives Bitter. 

Again, if the stimuli of sense derived from Contraries are themselves
Contrary, and if Contraries cannot be conceived as subsisting together
in the same individual subject, and if Contraries, e.g. Sweet and
Bitter, come under one and the same sense-faculty, we must conclude
that it is impossible to discern them coinstantaneously. It is likewise
clearly impossible so to discern such homogeneous sensibles as are
not [indeed] Contrary, [but are yet of different species]. For these
are, [in the sphere of colour, for instance], classed some with White,
others with Black, and so it is, likewise, in the other provinces
of sense; for example, of savours, some are classed with Sweet, and
others with Bitter. Nor can one discern the components in compounds
coinstantaneously (for these are ratios of Contraries, as e.g. the
Octave or the Fifth); unless, indeed, on condition of perceiving them
as one. For thus, and not otherwise, the ratios of the extreme sounds
are compounded into one ratio: since we should have together the ratio,
on the one hand, of Many to Few or of Odd to Even, on the other, that
of Few to Many or of Even to Odd [and these, to be perceived together,
must be unified]. 

If, then, the sensibles denominated co-ordinates though in different
provinces of sense (e.g. I call Sweet and White co-ordinates though
in different provinces) stand yet more aloof, and differ more, from
one another than do any sensibles in the same province; while Sweet
differs from White even more than Black does from White, it is still
less conceivable that one should discern them [viz. sensibles in different
sensory provinces whether co-ordinates or not] coinstantaneously than
sensibles which are in the same province. Therefore, if coinstantaneous
perception of the latter be impossible, that of the former is a fortiori
impossible. 

Some of the writers who treat of concords assert that the sounds combined
in these do not reach us simultaneously, but only appear to do so,
their real successiveness being unnoticed whenever the time it involves
is [so small as to be] imperceptible. Is this true or not? One might
perhaps, following this up, go so far as to say that even the current
opinion that one sees and hears coinstantaneously is due merely to
the fact that the intervals of time [between the really successive
perceptions of sight and hearing] escape observation. But this can
scarcely be true, nor is it conceivable that any portion of time should
be [absolutely] imperceptible, or that any should be absolutely unnoticeable;
the truth being that it is possible to perceive every instant of time.
[This is so]; because, if it is inconceivable that a person should,
while perceiving himself or aught else in a continuous time, be at
any instant unaware of his own existence; while, obviously, the assumption,
that there is in the time-continuum a time so small as to be absolutely
imperceptible, carries the implication that a person would, during
such time, be unaware of his own existence, as well as of his seeing
and perceiving; [this assumption must be false]. 

Again, if there is any magnitude, whether time or thing, absolutely
imperceptible owing to its smallness, it follows that there would
not be either a thing which one perceives, or a time in which one
perceives it, unless in the sense that in some part of the given time
he sees some part of the given thing. For [let there be a line ab,
divided into two parts at g, and let this line represent a whole object
and a corresponding whole time. Now,] if one sees the whole line,
and perceives it during a time which forms one and the same continuum,
only in the sense that he does so in some portion of this time, let
us suppose the part gb, representing a time in which by supposition
he was perceiving nothing, cut off from the whole. Well, then, he
perceives in a certain part [viz. in the remainder] of the time, or
perceives a part [viz. the remainder] of the line, after the fashion
in which one sees the whole earth by seeing some given part of it,
or walks in a year by walking in some given part of the year. But
[by hypothesis] in the part bg he perceives nothing: therefore, in
fact, he is said to perceive the whole object and during the whole
time simply because he perceives [some part of the object] in some
part of the time ab. But the same argument holds also in the case
of ag [the remainder, regarded in its turn as a whole]; for it will
be found [on this theory of vacant times and imperceptible magnitudes]
that one always perceives only in some part of a given whole time,
and perceives only some part of a whole magnitude, and that it is
impossible to perceive any [really] whole [object in a really whole
time; a conclusion which is absurd, as it would logically annihilate
the perception of both Objects and Time]. 

Therefore we must conclude that all magnitudes are perceptible, but
their actual dimensions do not present themselves immediately in their
presentation as objects. One sees the sun, or a four-cubit rod at
a distance, as a magnitude, but their exact dimensions are not given
in their visual presentation: nay, at times an object of sight appears
indivisible, but [vision like other special senses, is fallible respecting
'common sensibles', e.g. magnitude, and] nothing that one sees is
really indivisible. The reason of this has been previously explained.
It is clear then, from the above arguments, that no portion of time
is imperceptible. 

But we must here return to the question proposed above for discussion,
whether it is possible or impossible to perceive several objects coinstantaneously;
by 'coinstantaneously' I mean perceiving the several objects in a
time one and indivisible relatively to one another, i.e. indivisible
in a sense consistent with its being all a continuum. 

First, then, is it conceivable that one should perceive the different
things coinstantaneously, but each with a different part of the Soul?
Or [must we object] that, in the first place, to begin with the objects
of one and the same sense, e.g. Sight, if we assume it [the Soul qua
exercising Sight] to perceive one colour with one part, and another
colour with a different part, it will have a plurality of parts the
same in species, [as they must be,] since the objects which it thus
perceives fall within the same genus? 

Should any one [to illustrate how the Soul might have in it two different
parts specifically identical, each directed to a set of aistheta the
same in genus with that to which the other is directed] urge that,
as there are two eyes, so there may be in the Soul something analogous,
[the reply is] that of the eyes, doubtless, some one organ is formed,
and hence their actualization in perception is one; but if this is
so in the Soul, then, in so far as what is formed of both [i.e. of
any two specifically identical parts as assumed] is one, the true
perceiving subject also will be one, [and the contradictory of the
above hypothesis (of different parts of Soul remaining engaged in
simultaneous perception with one sense) is what emerges from the analogy];
while if the two parts of Soul remain separate, the analogy of the
eyes will fail, [for of these some one is really formed].

Furthermore, [on the supposition of the need of different parts of
Soul, co-operating in each sense, to discern different objects coinstantaneously],
the senses will be each at the same time one and many, as if we should
say that they were each a set of diverse sciences; for neither will
an 'activity' exist without its proper faculty, nor without activity
will there be sensation. 

But if the Soul does not, in the way suggested [i.e. with different
parts of itself acting simultaneously], perceive in one and the same
individual time sensibles of the same sense, a fortiori it is not
thus that it perceives sensibles of different senses. For it is, as
already stated, more conceivable that it should perceive a plurality
of the former together in this way than a plurality of heterogeneous
objects. 

If then, as is the fact, the Soul with one part perceives Sweet, with
another, White, either that which results from these is some one part,
or else there is no such one resultant. But there must be such an
one, inasmuch as the general faculty of sense-perception is one. What
one object, then, does that one faculty [when perceiving an object,
e.g. as both White and Sweet] perceive? [None]; for assuredly no one
object arises by composition of these [heterogeneous objects, such
as White and Sweet]. We must conclude, therefore, that there is, as
has been stated before, some one faculty in the soul with which the
latter perceives all its percepts, though it perceives each different
genus of sensibles through a different organ. 

May we not, then, conceive this faculty which perceives White and
Sweet to be one qua indivisible [sc. qua combining its different simultaneous
objects] in its actualization, but different, when it has become divisible
[sc. qua distinguishing its different simultaneous objects] in its
actualization? 

Or is what occurs in the case of the perceiving Soul conceivably analogous
to what holds true in that of the things themselves? For the same
numerically one thing is white and sweet, and has many other qualities,
[while its numerical oneness is not thereby prejudiced] if the fact
is not that the qualities are really separable in the object from
one another, but that the being of each quality is different [from
that of every other]. In the same way therefore we must assume also,
in the case of the Soul, that the faculty of perception in general
is in itself numerically one and the same, but different [differentiated]
in its being; different, that is to say, in genus as regards some
of its objects, in species as regards others. Hence too, we may conclude
that one can perceive [numerically different objects] coinstantaneously
with a faculty which is numerically one and the same, but not the
same in its relationship [sc. according as the objects to which it
is directed are not the same]. 

That every sensible object is a magnitude, and that nothing which
it is possible to perceive is indivisible, may be thus shown. The
distance whence an object could not be seen is indeterminate, but
that whence it is visible is determinate. We may say the same of the
objects of Smelling and Hearing, and of all sensibles not discerned
by actual contact. Now, there is, in the interval of distance, some
extreme place, the last from which the object is invisible, and the
first from which it is visible. This place, beyond which if the object
be one cannot perceive it, while if the object be on the hither side
one must perceive it, is, I presume, itself necessarily indivisible.
Therefore, if any sensible object be indivisible, such object, if
set in the said extreme place whence imperceptibility ends and perceptibility
begins, will have to be both visible and invisible their objects,
whether regarded in general or at the same time; but this is impossible.

This concludes our survey of the characteristics of the organs of
Sense-perception and their objects, whether regarded in general or
in relation to each organ. Of the remaining subjects, we must first
consider that of memory and remembering.