The term being
has several senses, which we have classified in our discussion Footnote 1Aristot. Met. 5.7. of the number of senses in which terms are used. It denotes first the what
of a thing, i.e. the individuality; and then the quality or quantity or any other such category. Now of all these senses which being
has, the primary sense is clearly the what,
which denotes the substance
(because when we describe the quality of a particular thing we say that it is good or bad,
and not five feet high
or a man
; but when we describe what it is, we say not that it is white
or hot
or five feet high,
but that it is a man
or a god
), and all other things are said to be
because they are either quantities or qualities or affections or some other such thing.
Hence one might raise the question whether the terms to walk
and to be well
and to sit
signify each of these things as being,
or not; and similarly in the case of any other such terms; for not one of them by nature has an independent existence or can be separated from its substance. Rather, if anything it is the thing which walks or sits or is well that is existent.
The reason why these things are more truly existent is because their subject is something definite; i.e. the substance and the individual, which is clearly implied in a designation of this kind, since apart from it we cannot speak of the good
or sitting.
Clearly then it is by reason of the substance that each of the things referred to exists.
Hence that which is primarily, not in a qualified sense but absolutely, will be substance.
Now primary
has several meanings; but nevertheless substance is primary in all senses, both in definition and in knowledge and in time. For none of the other categories can exist separately, but substance alone;
and it is primary also in definition, because in the formula of each thing the formula of substance must be inherent; and we assume that we know each particular thing most truly when we know what man
or fire
is— rather than its quality or quantity or position; because we know each of these points too when we know what the quantity or quality is.
Indeed, the question which was raised long ago, is still and always will be, and which always baffles us—What is Being?
—is in other words What is substance?
Some say that it is one Footnote 2The Milesians and Eleatics. ; others, more than one; some, finite Footnote 3The Pythagoreans and Empedocles. ; others, infinite. Footnote 4Anaxagoras and the Atomists. And so for us too our chief and primary and practically our only concern is to investigate the nature of being
in the sense of substance.