Since the subject of our inquiry is substance, let us return to it. Just as the substrate and the essence and the combination of these are called substance, so too is the universal. With two of these we have already dealt, i.e. with the essence Footnote 1Chs. 4-5.,10-12. and the substrate Footnote 2Ch. 3. ; of the latter we have said that it underlies in two senses—either being an individual thing (as the animal underlies its attributes), or as matter underlies the actuality.
The universal also is thought by some Footnote 3The Platonists. to be in the truest sense a cause and a principle. Let us therefore proceed to discuss this question too; for it seems impossible that any universal term can be substance.
First, the substance of an individual is the substance which is peculiar to it and belongs to nothing else; whereas the universal is common; for by universal we mean that which by nature appertains to several things.
Of what particular, then, will the universal be the substance? Either of all or of none. But it cannot be the substance of all; while, if it is to be the substance of one, the rest also will be that one; because things whose substance is one have also one essence and are themselves one.
Again, substance means that which is not predicated of a subject, whereas the universal is always predicated of some subject.
But perhaps although the universal cannot be substance in the sense that essence is, it can be present in the essence, as animal
can be present in man
and horse.
Then clearly there is in some sense a formula of the universal. It makes no difference even if there is not a formula of everything that is in the substance; for the universal will be none the less the substance of something; e.g., man
will be the substance of the man in whom it is present. Thus the same thing will happen again Footnote 4i.e., the argument in ch. 3 will apply to this case also. ; e.g. animal
will be the substance of that in which it is present as peculiar to it.
Again, it is impossible and absurd that the individual or substance, if it is composed of anything, should be composed not of substances nor of the individual, but of a quality; for then non-substance or quality will be prior to substance or the individual. Which is impossible; for neither in formula nor in time nor in generation can the affections of substance be prior to the substance, since then they would be separable.
Again, a substance will be present in Socrates,
who is a substance; so that it will be the substance of two things. And in general it follows that if man
and all terms used in this way are substance, none of the elements in the formula is the substance of anything, nor can it exist apart from the species or in anything else; I mean, e.g., that neither animal
nor any other element of the formula can exist apart from the particular species.
If we look at the question from this standpoint it is obvious that no universal attribute is substance; and it is also clear from the fact that none of the common predicates means so-and-so,
but such and-such.
Otherwise amongst many other awkward consequences we have the third man.
Footnote 5See note on Aristot. Met. 1.9.3.
Again, it is clear in this way too. Substance can not consist of substances actually present in it; for that which is actually two can never be actually one, whereas if it is potentially two it can be one. E.g., the double consists of two halves—that is, potentially; for the actualization separates the halves.
Thus if substance is one, it cannot consist of substances present in it even in this sense, as Democritus rightly observes; he says that it is impossible for two to come from one, or one from two, because he identifies substance with the atoms. Footnote 6Cf. Aristot. De Caelo 303a 6, Aristot. De Gen. et Corr. 325a 35.
Clearly then the same will also hold good in the case of number (assuming that number is a composition of units, as it is said to be by some); because either 2 is not 1, or there is not actually a unit in it.
The consequence involves a difficulty; for if no substance can consist of universals, because they mean of such a kind,
and not a particular thing; and if no substance can be actually composed of substances, every substance will be incomposite, and so there will be no formula of any substance.
But in point of fact it is universally held, and has been previously stated, Footnote 7Aristot. Met. 7.5.5-7. that substance is the only or chief subject of definition; but on this showing there is no definition even of substance. Then there can be no definition of anything; or rather in a sense there can, and in a sense cannot. What this means will be clearer from what follows later. Footnote 8Aristot. Met. 7.15, Aristot. Met. 8.6.