Book 5

Section 9

The same means (a) accidentally the same. E.g., white and cultured are the same because they are accidents of the same subject; and man is the same as cultured, because one is an accident of the other; and cultured is the same as man because it is an accident of man; and cultured man is the same as each of the terms cultured and man, and vice versa; for both man and cultured are used in the same way as cultured man, and the latter in the same way as the former.

Hence none of these predications can be made universally. For it is not true to say that every man is the same as the cultured; because universal predications are essential to things, but accidental predications are not so, but are made of individuals and with a single application. Socrates and cultured Socrates seem to be the same; but Socrates is not a class-name, and hence we do not say every Socrates as we say every man.

Some things are said to be the same in this sense, but (b) others in an essential sense, in the same number of senses as the one is essentially one; for things whose matter is formally or numerically one, and things whose substance is one, are said to be the same. Thus sameness is clearly a kind of unity in the being, either of two or more things, or of one thing treated as more than one; as, e.g., when a thing is consistent with itself; for it is then treated as two.

Things are called other of which either the forms or the matter or the definition of essence is more than one; and in general other is used in the opposite senses to same.

Things are called different which, while being in a sense the same, are other not only numerically, but formally or generically or analogically; also things whose genus is not the same; and contraries; and all things which contain otherness in their essence.

Things are called like which have the same attributes in all respects; or more of those attributes the same than different; or whose quality is one. Also that which has a majority or the more important of those attributes of something else in respect of which change is possible (i.e. the contraries) is like that thing. And unlike is used in the opposite senses to like.