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By being 'present in a subject' I do not mean present as parts are

present in a whole, but being incapable of existence apart from the

said subject.

Some things, again, are present in a subject, but are never

predicable of a subject. For instance, a certain point of

grammatical knowledge is present in the mind, but is not predicable of

any subject; or again, a certain whiteness may be present in the

body (for colour requires a material basis), yet it is never

predicable of anything.

Other things, again, are both predicable of a subject and present in

a subject. Thus while knowledge is present in the human mind, it is

predicable of grammar.

There is, lastly, a class of things which are neither present in a

subject nor predicable of a subject, such as the individual man or the

individual horse. But, to speak more generally, that which is

individual and has the character of a unit is never predicable of a

subject. Yet in some cases there is nothing to prevent such being

present in a subject. Thus a certain point of grammatical knowledge is

present in a subject.





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When one thing 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',