Metaphysics

’Being’ is said in one sense accidentally, and in another in itself. Accidentally, for instance, we say that the just person is musical, and the man is musical, and the musical person is a man, speaking in a way similar to saying that the musical person builds because it is accidental to the builder to be musical, or to the musical person to be a builder (for to say that this is that means that that is accidental to this) — and so it is with the cases mentioned; for when we say that the man is musical and the musical person is a man, or that the white is musical or this is white, it is in the one case because both are accidental to the same thing, in another because it is accidental to a being, and we say that the musical person is a man because the musical is accidental to this person (and in this way ‘not to be white’ is also said, because that to which it is accidental is). — Those things, then, which are said to be accidentally, are so called either because both belong to the same being, or because it belongs to that being, or because that itself is to which belongs that of which it is predicated. But those things are said to be in themselves which are signified by the schemes of the category; for in as many ways as these are said, in so many ways does ‘to be’ signify. Since, then, of the predicates, some signify what a thing is, others quality, others quantity, others relation, others doing or suffering, others where, others when, to be signifies the same as each of these; for there is no difference between ‘a man is recovering’ and ‘a man recovers’, nor between ‘a man is walking’ or ‘cutting’ and ‘a man walks’ or ‘cuts’, and similarly in the other cases. Further, ‘to be’ and ‘is’ signify that something is true, and ‘not to be’ that it is not true but false, similarly in affirmation and negation; for instance, ‘Socrates is musical’ means that this is true, or ‘Socrates is not white’ means that this is true, and ‘the diagonal is not commensurable’ means that this is false. Further, ‘to be’ and ‘being’ signify, of these things mentioned, that some are potentially and others actually; for we say both that which is potentially seeing is seeing, and that which is actually, and similarly to know is said both of that which is able to use knowledge and of that which is using it, and that is at rest both to which rest already belongs and that which is able to be at rest. And similarly also in the case of substances; for we say that Hermes is in the stone, and the half of the line is, and corn is which is not yet ripe. But when a thing is possible and when it is not yet so, must be distinguished elsewhere.

’Substance’ is said of the simple bodies, such as earth, fire, water, and all such things, and in general of bodies and the things composed of them, both animals and divine beings (demons), and the parts of these. All these are called substance because they are not said of a subject, but other things are said of them. And in another way, that which is the cause of being, immanent in such things as are not said of a subject, for instance the soul in the animal. Further, any parts which are immanent in such things, defining them and signifying ‘a this’, and which if they are destroyed destroy the whole, as some say the plane destroys the body, and the line the plane. And in general number seems to some to be of this nature (for if it is destroyed, they say, nothing exists, and it defines all things). Further, the essence, of which the formula is a definition, this also is called the substance of each thing. It follows, then, that substance is said in two ways: both the ultimate subject, which is no longer said of anything else, and that which, being ‘a this’, is also separable; and of this nature is the shape and the form of each thing.