The Categories | Page 4

is predicated of another, all that which is predicable of
the predicate will be predicable also of the subject. Thus, 'man' is
predicated of the individual man; but 'animal' is predicated of 'man'; it
will, therefore, be predicable of the individual man also: for the
individual man is both 'man' and 'animal'.
If genera are different and co-ordinate, their differentiae are themselves
different in kind. Take as an instance the genus 'animal' and the genus
'knowledge'. 'With feet', 'two-footed', 'winged', 'aquatic', are differentiae
of 'animal'; the species of knowledge are not distinguished by the same
differentiae. One species of knowledge does not differ from another in
being 'two-footed'.

But where one genus is subordinate to another, there is nothing to
prevent their having the same differentiae: for the greater class is
predicated of the lesser, so that all the differentiae of the predicate will
be differentiae also of the subject.
Part 4
Expressions which are in no way composite signify substance, quantity,
quality, relation, place, time, position, state, action, or affection. To
sketch my meaning roughly, examples of substance are 'man' or 'the
horse', of quantity, such terms as 'two cubits long' or 'three cubits long',
of quality, such attributes as 'white', 'grammatical'. 'Double', 'half',
'greater', fall under the category of relation; 'in a the market place', 'in
the Lyceum', under that of place; 'yesterday', 'last year', under that of
time. 'Lying', 'sitting', are terms indicating position, 'shod', 'armed', state;
'to lance', 'to cauterize', action; 'to be lanced', 'to be cauterized',
affection.
No one of these terms, in and by itself, involves an affirmation; it is by
the combination of such terms that positive or negative statements arise.
For every assertion must, as is admitted, be either true or false, whereas
expressions which are not in any way composite such as 'man', 'white',
'runs', 'wins', cannot be either true or false.
Part 5
Substance, in the truest and primary and most definite sense of the
word, is that which is neither predicable of a subject nor present in a
subject; for instance, the individual man or horse. But in a secondary
sense those things are called substances within which, as species, the
primary substances are included; also those which, as genera, include
the species. For instance, the individual man is included in the species
'man', and the genus to which the species belongs is 'animal'; these,
therefore-that is to say, the species 'man' and the genus 'animal,-are
termed secondary substances.
It is plain from what has been said that both the name and the definition
of the predicate must be predicable of the subject. For instance, 'man' is

predicted of the individual man. Now in this case the name of the
species man' is applied to the individual, for we use the term 'man' in
describing the individual; and the definition of 'man' will also be
predicated of the individual man, for the individual man is both man
and animal. Thus, both the name and the definition of the species are
predicable of the individual.
With regard, on the other hand, to those things which are present in a
subject, it is generally the case that neither their name nor their
definition is predicable of that in which they are present. Though,
however, the definition is never predicable, there is nothing in certain
cases to prevent the name being used. For instance, 'white' being
present in a body is predicated of that in which it is present, for a body
is called white: the definition, however, of the colour white' is never
predicable of the body.
Everything except primary substances is either predicable of a primary
substance or present in a primary substance. This becomes evident by
reference to particular instances which occur. 'Animal' is predicated of
the species 'man', therefore of the individual man, for if there were no
individual man of whom it could be predicated, it could not be
predicated of the species 'man' at all. Again, colour is present in body,
therefore in individual bodies, for if there were no individual body in
which it was present, it could not be present in body at all. Thus
everything except primary substances is either predicated of primary
substances, or is present in them, and if these last did not exist, it would
be impossible for anything else to exist.
Of secondary substances, the species is more truly substance than the
genus, being more nearly related to primary substance. For if any one
should render an account of what a primary substance is, he would
render a more instructive account, and one more proper to the subject,
by stating the species than by stating the genus. Thus, he would give a
more instructive account of an individual man by stating that he was
man than by stating that he was