^ f. UBBARV - JScholarship - Johns Hopkins University

VISION 23
object^: so that those in whom the light within the eye
is defective should see worse by day ^- Or if (as Empedocles
thinks) its like augments the visual fire in the daytime ^
while its opposite destroys or thwarts it, then all should see
white objects better by day, both those whose internal
light is less and those whose internal light is greater;
while again all should see black objects better by night.
The fact is, however, that all animals except a very few see
all objects better by day than in the night-time. It is
natural to suppose that in these few their native fire has
this peculiar power, just as there are animals whose eyes
in virtue of their colour are luminous at night-*. Again,
as regards the eyes in which the fire and water are mixed
in equal proportions, it must follow that either is in turn
unduly augmented by day or by night: hence, if water
or fire thwarts vision by being in excess, the disposition
(Siaöeo-ts) of all eyes would be pretty nearly alike ^.'
Democritus.
§ 13. For Democritus, as for Empedocles, the möst General
obvious explanation of perception seemed to be that which ph^ica/ ^
showed how particles of external things come into the theory of
pores of the sensory organs. He differed from Empedocles tus in its
in his doctrine of the existence of void, which Empedocles bearing on
Visual
did not allow. They agreed, however, in the belief that function:
•* This is perhaps—though see note 4 infra—an arg. ad kominem
against Empedocles: Theophrastus, as a disciple of Aristotle, would
not hold that the eyes contain a ' small fire,' to be quenched by the
greater fire of the sun.
^ Instead of better, as Empedocles asserts
' i. e. if (instead of the greater fire without destroying the less within
the eye) the daylight augments the intra-ocular fire.
* Not ' cutis noctu magis splendet,' as in Wimmer's Latin version.
There would seem to be here on the critic's part an admission which
is contrary to the teaching of Aristotle. Theophrastus seems to
attribute the capacity of some animals to see by night to the possession
of a peculiar fire in their eyes.
° i. e. the so-called best dass of eyes, having water and fire in equal
proportions, would both by day and by night, in one or the other way,
be out of keeping with the conditions of perfect vision, and would
therefore not have the superiority claimed for them by Empedocles:
they would be no better than the eyes already referred to.