On Sense And The Sensible   

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