But, in the first place, Matter does not possess or acquire Form as its life or its Act; Form enters it from without, and remains foreign to its nature.Secondly, Form in the Intellectual is an Act and a motion; in the Sensible Motion is different from Form and accidental to it: Form in relation to Matter approximates rather to Stability than to Motion; for by determining Matter's indetermination it confers upon it a sort of repose.
In the higher realm Identity and Difference presuppose a unity at once identical and different: a thing in the lower is different only by participation in Difference and in relation to some other thing; Identity and Difference are here predicated of the particular, which is not, as in that realm, a posterior.
As for Stability, how can it belong to Matter, which is distorted into every variety of mass, receiving its forms from without, and even with the aid of these forms incapable of offspring.
This mode of division must accordingly be abandoned.
3.How then do we go to work?
Let us begin by distinguishing Matter, Form, the Mixture of both, and the Attributes of the Mixture.The Attributes may be subdivided into those which are mere predicates, and those serving also as accidents.The accidents may be either inclusive or included; they may, further, be classified as activities, experiences, consequents.
Matter will be found common to all substances, not however as a genus, since it has no differentiae- unless indeed differentiae be ascribed to it on the ground of its taking such various forms as fire and air.
It may be held that Matter is sufficiently constituted a genus by the fact that the things in which it appears hold it in common, or in that it presents itself as a whole of parts.In this sense Matter will indeed be a genus, though not in the accepted sense of the term.Matter, we may remark, is also a single element, if the element as such is able to constitute a genus.
Further, if to a Form be added the qualification "bound up with, involved in Matter," Matter separates that Form from other Forms: it does not however embrace the whole of Substantial Form [as, to be the genus of Form, it must].
We may, again, regard Form as the creator of Substance and make the Reason-Principle of Substance dependent upon Form: yet we do not come thereby to an understanding of the nature of Substance.
We may, also, restrict Substance to the Composite.Matter and Form then cease to be substances.If they are Substance equally with the Composite, it remains to enquire what there is common to all three.
The "mere predicates" fall under the category of Relation: such are cause and element.The accidents included in the composite substances ire found to be either Quality or Quantity; those which are inclusive are of the nature of Space and Time.Activities and experiences comprise Motions; consequents Space and Time, which are consequents respectively of the Composites and of Motion.
The first three entities [Matter, Form, Composite] go, as we have discovered, to make a single common genus, the Sensible counterpart of Substance.Then follow in order Relation, Quantity, Quality, Time-during-which, Place-in-which, Motion; though, with Time and Space already included [under Relation], Time-during-which and Place-in-which become superfluous.
Thus we have five genera, counting the first three entities as one.If the first three are not massed into a unity, the series will be Matter, Form, Composite, Relation, Quantity, Quality, Motion.The last three may, again, be included in Relation, which is capable of bearing this wider extension.
4.What, then, we have to ask, is the constant element in the first three entities? What is it that identifies them with their inherent Substance?
Is it the capacity to serve as a base? But Matter, we maintain, serves as the base and seat of Form: Form, thus, will be excluded from the category of Substance.Again, the Composite is the base and seat of attributes: hence, Form combined with Matter will be the basic ground of Composites, or at any rate of all posteriors of the Composite- Quantity, Quality, Motion, and the rest.
But perhaps we may think Substance validly defined as that which is not predicated of anything else.White and black are predicated of an object having one or other of these qualities; double presupposes something distinct from itself- we refer not to the half, but to the length of wood of which doubleness is affirmed.
father qua father is a predicate; knowledge is predicated of the subject in whom the knowledge exists; space is the limit of something, time the measure of something.Fire, on the other hand, is predicated of nothing; wood as such is predicated of nothing; and so with man, Socrates, and the composite substance in general.
Equally the Substantial Form is never a predicate, since it never acts as a modification of anything.Form is not an attribute of Matter hence, is not predicable of Matter it is simply a constituent of the Couplement.On the other hand, the Form of a man is not different from the man himself [and so does not "modify" the Couplement].
Matter, similarly, is part of a whole, and belongs to something else only as to a whole and not as to a separate thing of which it is predicated.White, on the contrary, essentially belongs to something distinct from itself.
We conclude that nothing belonging to something else and predicated of it can be Substance.Substance is that which belongs essentially to itself, or, in so far as it is a part of the differentiated object, serves only to complete the Composite.Each or either part of the Composite belongs to itself, and is only affirmed of the Composite in a special sense: only qua part of the whole is it predicated of something else; qua individual it is never in its essential nature predicated of an external.