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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