Page:O. F. Owen's Organon of Aristotle Vol. 2 (1853).djvu/274

 622 man, in the same manner as the statue there. They also describe it thus, difference is what is naturally adapted to separate things which are under the same genus, as rational and irrational separate man and horse, which are under the same genus, animal. Again, they give it in this way: difference is that by which each singular thing differs, for man and horse do not differ as to genus, for both we and horses are animals, but the addition of rational separates us from them; again, both we and the gods are rational, but the addition of mortal separates us from them. They however who more nicely discuss what pertains to difference, say that it is not any casual thing dividing those under the same genus, but such as contributes to the essence, and to the definition of the essence of a thing, and which is part of the thing. For to be naturally adapted to sail is not the difference, though it is the property of man, since we may say that of animals, some are naturally adapted to sail, but others not, separating man from other animals; yet a natural ability to sail does not complete the essence, neither is a part of it, but only an aptitude of it, because it is not such a difference as those which are called specific differences. Wherefore specific differences will be such as produce another species, and which are assumed in explaining the very nature of a thing: and concerning difference this is sufficient.

they divide in four ways: for it is that which happens to some one species alone, though not to every (individual of that species), as to a man to heal, or to geometrize: that also which happens to a whole species, though not to that alone, as to man to be a biped: that again, which happens to a species alone, and to every (individual of it), and at a certain time, as to every man to be-