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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。
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