strictly speaking, in itself, but made visible by colour, which is foreign to it. Such is air, and water, and many solid bodies; yet neither air nor water, as air or water, is diaphanous, but the same nature is present in both those elements, which is in the eternal supernal body. Light is the active state of that same diaphanous, in so far as it is diaphanous, and darkness is the same in its state of potentiality. But light is the colour, as it were, of the diaphanous, when made diaphanous in reality by fire, or other such element as the supernal body; for to it belongs a something which is identical with fire. We have thus said what is the diaphanous and what light, and have shewn that neither of them is fire, nor a body, strictly speaking, nor an emanation from a body, (as, in that case, they would be corporeal), but that they are the presence in the diaphanous of fire or something analogous to fire, since two bodies cannot possibly coexist in one and the same body.
Light seems to be the opposite to darkness; and as darkness is the absence of a particular state of the diaphanous, it is evident that the presence of that state must be light.
Thus Empedocles, or whoever else may have held the same opinion, was wrong in supposing that light was transported and manifested, without our consciousness, between the Earth and surrounding space; for the opinion is opposed as well to sound conclusion
