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the name, but also the definition, applies to the subject: we should

use both the definition of the species and that of the genus with

reference to the individual man. Thus substance cannot be present in a

subject.

Yet this is not peculiar to substance, for it is also the case

that differentiae cannot be present in subjects. The characteristics

'terrestrial' and 'two-footed' are predicated of the species 'man',

but not present in it. For they are not in man. Moreover, the

definition of the differentia may be predicated of that of which the

differentia itself is predicated. For instance, if the

characteristic 'terrestrial' is predicated of the species 'man', the

definition also of that characteristic may be used to form the

predicate 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'