Chapter 9
We must next define the genera of the Categories, in which the above-named four (differences) are inherent. Now these are ten in number; what a thing is, quantity, quality, relation, where, when, position, possession, action, passion, for accident, and genus, and property, and definition will always be in one of these categories, since all propositions through these signify either what a thing is, or quality, or quantity, or some other category. Moreover, it is evident from these that he who signifies what a thing is, at one time signifies substance, at another quality, and at another some other category. For when man being proposed, he says that the thing proposed is man or animal, he says what it is, and signifies substance; but when white colour being proposed, he says that the thing proposed is white or colour, he says what it is, and signifies quality. So also, if when the magnitude of one cubit is proposed, he says that what is proposed is a cubit in size, he will say what it is, and will signify quantity, and so of the rest, for each of these, both if it be itself predicated of itself, and if genus (be predicated) of it, signifies what a thing is. When however (it is spoken) of another thing, it does not signify what it is, but quantity or quality, or some other category, so that the things about which and from which arguments (subsist), are these and so many; but how we shall take them, and by what we shall be well provided with them, we must declare hereafter.
