(2) in order of knowledge, (3) in time. For (3) of the other categories none can exist independently, but only substance. And (1) in formula also this is first; for in the formula of each term the formula of its substance must be present. And (2) we think we know each thing most fully, when we know what it is, e.g. what man is or what fire is, rather than when we know its quality, its quantity, or where it is; since we know each of these predicates also, only when we know what the quantity or the quality is.
And indeed the question which was raised of old and is raised now and always, and is always the subject of doubt, viz. what being is, is just the question, what is substance? For it is this that some assert to be one, others more than one, and that some assert to be limited in number, others unlimited. And so we also must consider chiefly and primarily and almost exclusively what that is which is in this sense.
Chapter 2
Substance is thought to belong most obviously to bodies; and so we say that both animals and plants and their parts are substances, and so are natural bodies such as fire and water and earth and everything of the sort, and all things that are parts of these or composed of these (either of parts or of the whole bodies), e.g. the heaven and its parts, stars and moon and sun. But whether these alone are substances, or there are also others, or only some of these, or some of these and some other things[1] are substances, or none of these but only some other things, must be considered. Some think the limits of body, i.e. surface, line, point, and unit, are substances, and more so than body or the solid.
Further, some do not think there is anything substantial besides sensible things, but others think there are eternal substances which are more in number and more real, e.g. Plato posited two kinds of substance — the Forms and the objects of mathematics — as well as a third kind, viz. the substance of
- ↑ 1028b14 read ἢ τούτων τινὲς ἢ καὶ ἄλλαι. The possibilities are (a) all of these, (b) all of these and some others, (c) some of these, (d) some of these and some others, (e) some others.
