Chapters 9-10 (variants)

The term genus is used in three senses: in one sense, as coming from the progenitor, as those descended from Israel are called Israelites; in the second sense, as coming from the place of origin, as those from Jerusalem are called Hieroso-lymites and those from Palestine Palestinians; and, in the third sense, that is called genus which is divided into species. With this last the philosophers are concerned, and they define it by saying that genus is that which is predicated in respect to their common essence of several things which are specifically different.

The term species has two meanings. Thus, appearance and form are called species, as for example, the species of the statue. That is also called species which is subordinate to genus, that is to say, divided off from a genus. With this last the philosophers are concerned.

Now, when we are discussing genus, we mentioned species by saying that genus was that which was divided into species. Again, when discussing species, we mentioned genus by saying that species was that which was divided off from genus. One should know that when we discuss the father we must needs think of the son, too (for he is a father who has a son), and when we discuss the son we must needs think of a father, too (for he is a son who has a father). And similarly in this case it is impossible to treat of the genus without the species, or the species without the genus, for the genus is definitely divided into the species and that which does not have species divided off from itself is not genus. In the same way, the species are divided off from the genus and those things which do not have a genus are not species. And just as the first man—that is to say, Adam—is not called a son, because he had no father, but is called a father because he did have sons; and just as Seth is called both son of him that begot him, for he had Adam for his father, and father of him begotten by him, for he did beget a son; and just as Abel is called a son, because he had Adam for his father, but is not called a father, because he had no son— so also is it with genus and species.

The first genus, which is not divided off from a genus and has no higher genus, is genus only and not a species. This is called a most general genus and they define it b