is individual, but the impression is not strictly true; for a
secondary substance is not an individual, but a class with a
certain qualification; for it is not one and single as a primary
substance is; the words 'man', 'animal', are predicable of more
than one subject.

Yet species and genus do not merely indicate quality, like the
term 'white'; 'white' indicates quality and nothing further, but
species and genus determine the quality with reference to a
substance: they signify substance qualitatively differentiated.
The determinate qualification covers a larger field in the case
of the genus that in that of the species: he who uses the word
'animal' is herein using a word of wider extension than he who
uses the word 'man'.

Another mark of substance is that it has no contrary. What could
be the contrary of any primary substance, such as the individual
man or animal? It has none. Nor can the species or the genus have
a contrary. Yet this characteristic is not peculiar to substance,
but is true of many other things, such as quantity. There is
nothing that forms the contrary of 'two cubits long' or of 'three
cubits long', or of 'ten', or of any such term. A man may contend
that 'much' is the contrary of 'little', or 'great' of 'small',
but of definite quantitative terms no contrary exists.

Substance, again, does not appear to admit of variation of
degree. I do not mean by this that one substance cannot be more
or less truly substance than another, for it has already been
stated' that this is the case; but that no single substance
admits of varying degrees within itself. For instance, one