Book 8
3
Hence it is clear that is has the same number of senses; for a thing is a threshold because it is situated in a particular way, and to be a threshold means to be situated in this particular way, and to be ice means to be condensed in this particular way. Some things have their being defined in all these ways: by being partly mixed, partly blended, partly bound, partly condensed, and partly subjected to all the other different processes; as, for example, a hand or a foot.
4
We must therefore comprehend the various kinds of differences—for these will be principles of being—i.e. the differences in degree, or in density and rarity, and in other such modifications, for they are all instances of excess and defect.
5
And if anything differs in shape or in smoothness or roughness, all these are differences in straightness and curvature. For some things mixture will constitute being, and the opposite state not-being.
5
From this it is evident that if substance is the cause of the existence of each thing, we must look among these differences for the cause of the being of each thing.
