cate of the species 'man':
for 'man' is terrestrial.

The fact that the parts of substances appear to be present in the
whole, as in a subject, should not make us apprehensive lest we should
have to admit that such parts are not substances: for in explaining the
phrase 'being present in a subject', we stated' that we meant
'otherwise than as parts in a whole'.

It is the mark of substances and of differentiae that, in all
propositions of which they form the predicate, they are predicated
univocally. For all such propositions have for their subject either the
individual or the species. It is true that, inasmuch as primary
substance is not predicable of anything, it can never form the
predicate of any proposition. But of secondary substances, the species
is predicated of the individual, the genus both of the species and of
the individual. Similarly the differentiae are predicated of the
species and of the individuals. Moreover, the definition of the species
and that of the genus are applicable to the primary substance, and that
of the genus to the species. For all that is predicated of the
predicate will be predicated also of the subject. Similarly, the
definition of the differentiae will be applicable to the species and to
the individuals. But it was stated above that the word 'univocal' was
applied to those things which had both name and definition in common.
It is, therefore, established that in every proposition, of which
either substance or a differentia forms the predicate, these are
predicated univocally.

All substance appears to signify that which is individual. In the case
of primary substance this is indisputably true, for the thing is a
unit. In the case of secondary substances, when we speak, for instance,
of 'man' or 'animal', our form of speech gives the impression that we
are here also indicating that which 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