As for what and what sort of thing we mean by substance, let us explain this by making, as it were, another fresh start. Perhaps in this way we shall also obtain some light upon that kind of substance which exists in separation from sensible substances. Since, then, substance is a kind of principle and cause, we had better pursue our inquiry from this point.
Now when we ask why a thing is, it is always in the sense why does A belong to B?
To ask why the cultured man is a cultured man is to ask either, as we have said, why the man is cultured, or something else. Now to ask why a thing is itself is no question; because when we ask the reason of a thing the fact must first be evident; e.g., that the moon suffers eclipse;
and because it is itself
is the one explanation and reason which applies to all questions such as why is man man?
or why is the cultured person cultured?
(unless one were to say that each thing is indivisible from itself, and that this is what being one
really means); but this, besides being a general answer, is a summary one. Footnote 1The argument is: The question Why is the cultured man a cultured man?
if it does not mean Why is the man cultured?
can only mean Why is a thing itself?
But when we ask a question the fact must be obvious; and since it is obvious that a thing is itself, because it is itself
(or because each thing is indivisible from itself
) is the one and only complete answer to all questions of this type. Since this answer (in either form) is clearly unsatisfactory, the question which it answers cannot be a proper question. We may, however, ask why a man is an animal of such-and-such a kind.
It is clear, then, that we are not asking why he who is a man is a man; therefore we are asking why A, which is predicated of B, belongs to B. (The fact that A does belong to B must be evident, for if this is not so, the question is pointless.) E.g., Why does it thunder?
means why is a noise produced in the clouds?
for the true form of the question is one thing predicated in this way of another.
Or again, why are these things, e.g. bricks and stones, a house?
Clearly then we are inquiring for the cause (i.e., to speak abstractly, the essence); which is in the case of some things, e.g. house or bed, the end , and in others the prime mover—for this also is a cause. We look for the latter kind of cause in the case of generation and destruction, but for the former also in the case of existence.
What we are now looking for is most obscure when one term is not predicated of another; e.g. when we inquire what man is; because the expression is a simple one not analyzed into subject and attributes. We must make the question articulate before we ask it; otherwise we get something which shares the nature of a pointless and of a definite question.
Now since we must know that the fact actually exists, it is surely clear that the question is why is the matter so-and-so?
e.g. why are these materials a house?
Because the essence of house is present in them. And this matter, or the body containing this particular form, is man. Thus what we are seeking is the cause (i.e. the form) in virtue of which the matter is a definite thing; and this is the substance of the thing.
Clearly then in the case of simple entities Footnote 2Pure forms which contain no matter; in their case the method just described obviously will not apply. They can only be apprehended intuitively (cf. Aristot. Met. 9.10.). inquiry and explanation are impossible; in such cases there is a different mode of inquiry.
Now since that which is composed of something in such a way that the whole is a unity; not as an aggregate is a unity, but as a syllable is Footnote 3This sentence is not finished; the parenthesis which follows lasts until the end of the chapter. —the syllable is not the letters, nor is BA the same as B and A; nor is flesh fire and earth; because after dissolution the compounds, e.g. flesh or the syllable, no longer exist; but the letters exist, and so do fire and earth.
Therefore the syllable is some particular thing; not merely the letters, vowel and consonant, but something else besides. And flesh is not merely fire and earth, or hot and cold, but something else besides.
Since then this something else must be either an element or composed of elements, (a) if it is an element, the same argument applies again; for flesh will be composed of this and fire and earth, and again of another element, so that there will be an infinite regression. And (b) if it is composed of elements, clearly it is composed not of one (otherwise it will itself be that element) but of several; so that we shall use the same argument in this case as about the flesh or the syllable.
It would seem, however, that this something else
is something that is not an element, but is the cause that this matter is flesh and that matter a syllable, and similarly in other cases.
And this is the substance of each thing, for it is the primary cause of its existence. And since, although some things are not substances, all substances are constituted in accordance with and by nature, substance would seem to be this nature,
which is not an element but a principle. Footnote 4i.e. the formal cause. Cf. Aristot. Met. 5.4.4-6. An element is that which is present as matter in a thing, and into which the thing is divided; e.g., A and B are the elements of the syllable.