Chapter 9

One must know that in the matter of equivocal terms there are three things to be asked: whether the term is equivocal, how many meanings it has, and of which of these it is a question. Now, first of all, it must be explained what an equivocal term is. Terms are equivocal when two or more things have one name, while each one of them has a different meaning, that is to say, takes a different definition. Such is the case with the term genusf for genus is of the number of equivocal terms. Thus, first of all, that is called a genus which is from a place of origin or from a progenitor, and both of these in two ways: either proximately or remotely. It is from the place of origin proximately, as when a person from Jerusalem is called a Hierosolymite, but remotely, as with a Palestinian from Palestine. Similarly, it is from the proximate progenitor, as when Achilles is called Peleides, because he was the son of Peleus; while it is from the more remote, as when Achilles is called Aeacides from his grandfather Aeacus—for the latter was the father of Peleus. Then, again, that relationship is called genus which exists between a person and his several descendants, as when all those descending from Israel are called Israelites. Now, these aforementioned kinds of genus are of no concern to the philosophers.

Again, that is called genus to which the species is subaltern. For example, under animal come man, the horse, and other species; hence, the animal is a genus. It is with this kind of genus that the philosophers are concerned and we define it by saying that genus is that which is predicated in respect to their essence of several things differing in species. Thus, animal, which is a genus, is predicated essentially of man, the horse, the ox, and a number of other things, all of which differ from one another in species. For the species of man is one thing, whereas that of the horse is another, and that of the ox is still another. The genus is predicated as to what something is, for, when we are asked what a man is, we reply that he is an animal. The same is true with the horse, because, when we are asked what it is, we reply that it is an animal. Thus, genus is that to which the species is subaltern. (And again, genus is that which is divided into species.) For genus is divided into species, is more general than the species, contains the species, and is higher than they.

Now, one should know that the more general is said to be superior, while the more particular is said to be inferior and is subject to predication. Thus, there are things which are subject with respect to existence. Such is substance, because it is subject with respect to the existence of the accident, since the accident subsists in it. There is also that which is subject with respect to predication, and this is the particular. For the genus is predicated of the species as the species is of the individuals. It is clear, however, that the genus is more general than the species, as the species is more general than the individual. In what follows we shall with the help of God learn more accurately about these things. But, now that we have discussed genus, let us also discuss species.

See alternate