them which the air contained were brought down by the rain-water,[1] and animals originated in a similar way.[2] Like Anaximander, Anaxagoras held that animals first arose in the moist element.[3]
137.Perception. In these scanty notices we seem to see traces of a polemical attitude towards Empedokles, and the same may be observed in what we are told of the theory of perception adopted by Anaxagoras, especially in the view that perception is of contraries.[4] The account which Theophrastos gives of this[5] is as follows:
But Anaxagoras says that perception is produced by opposites; for like things cannot be effected by like. He attempts to give a detailed enumeration of the particular senses. We see by means of the image in the pupil; but no image is cast upon what is of the same colour, but only on what is different. With most living creatures things are of a different colour to the pupil by day, though with some this is so by night, and these are accordingly keen-sighted at that time. Speaking generally, however, night is more of the same colour with the eyes than day. And an image is cast on the pupil by day, because light is a concomitant cause of the image, and because the prevailing colour casts an image more readily upon its opposite.[6]
It is in the same way that touch and taste discern their objects. That which is just as warm or just as cold as we are neither warms us nor cools us by its contact; and, in the same way, we do not apprehend the sweet and the sour by means of themselves. We know cold by warm, fresh by salt, and sweet by sour, in virtue of our deficiency in each; for all these are in us to begin with. And we smell and hear in the same manner; the former by means of the accompanying respiration, the latter by the sound penetrating to the brain, for the bone which surrounds this is hollow, and it is upon it that the sound falls.[7]
And all sensation implies pain, a view which would seem to be the consequence of the first assumption, for all unlike things
