(i.e. Place, [Greek:
pou]), or When (i.e. Time, [Greek: pote]), or Position ([Greek:
keisthai]), or Possession ([Greek: echein]), or Action ([Greek:
poiein]), or Passion ([Greek: paschein]). [Greek: ousia], the first
category, is subdivided into [Greek: prote ousia] or primary
substance, which is defined to be [Greek: tode ti], the singular thing
in which properties inhere, and to which predicates are attached, and
[Greek: deuterai] [Greek: onsiai], genera or species which can be
predicated of primary substances, and are therefore [Greek: onsia].
only in a secondary sense. Nevertheless, they too, after a certain
fashion, signify the singular thing, [Greek: tode ti]" (K. p. 3 b 12,
13). It is this doctrine of [Greek: prote onsia] that has raised
doubts with regard to the authenticity of the [Greek: Kategoriai] But
the tenfold classification, which has also been captiously objected
to, is given in an acknowledged writing of Aristotle's (see Topica, i.
9, p. 103 b 20).[5] At the same time it is at least remarkable that in
two places where the enumeration seems intended to be complete (_Met._
p. 1017 a 25; _An. Pos._ i. 22, p. 83 a 21), only eight are mentioned,
[Greek: exein] and [Greek: keisthai] being omitted. In other
passages[6] six, five, four, and three are given, frequently with some
addition, such as [Greek: kai ai allai k]. It is also to be observed
that, despite of this wavering, distinct intimations are given by
Aristotle that he regarded his list as complete, and he uses phrases
which would seem to indicate that the division had been exhaustively
carried out. He admits certainly that some predicates which come under
one category might be referred to another, but he declines to deduce
all from one highest class, or to recognize any relation of
subordination among the several classes.

The full import of the categories will never be adequately reached
from the point of view taken up in the [Greek: Kategoriai], which
bears all the marks of an early and preliminary study. For true
understanding we must turn to the _Metaphysics_, where the doctrine is
handled at large. The discussion of Being in that work starts with a
distinction that at once gives us a clue. [Greek: tho on] is spoken of
in many ways; of these four are classified--[Greek: tho on katha
sumbebekos, tho om hos alethes, tho on dunamei kai energeia], and
[Greek: tho on kata ta sche