has not breadth, is oppositely divided, but nothing else, so that the genus is again divided by negation.
Again (observe), whether species is assigned as difference, as they do who define contumely to be insolence with derision, for derision is a certain insolence, so that derision is not difference, but species.
Moreover, whether genus is assigned as difference as that virtue is a good or worthy habit, for good is the genus of virtue; or is good not a genus, but a difference, since it is true that the same thing cannot possibly be in two genera which do not comprehend each other? For neither does good contain habit, nor habit good, since not every habit is good, nor every thing good, a habit; hence they would not both be genera. If, then, habit be the genus of virtue, it is evident that good is not the genus, but rather the difference; besides, habit signifies what the virtue is, but good does not signify what, but what kind of thing it is; indeed difference, seems to signify quality.
Observe, also, whether the assigned difference does not signify quality, but this particular thing; since every difference appears to signify a certain quality.
Consider, also, whether difference is accidentally present with the thing defined, for no difference is of the number of things accidentally present, as neither is genus, since it is not possible that difference should be present with a certain thing, and not be present.
Moreover, if difference or species be predicated of genus, or something which is the subject of species, there will not be a definition, for nothing of what we have mentioned can possibly be predicated of genus, since genus is the most extensively spoken of all. Again, if the genus is predicated of the difference, for genus seems to be predicated not of difference, but of those of which difference (is predicated); thus, animal of man, and ox, and other pedestrian animals, and not of difference itself, which is spoken of species. For if animal were predicated of each of the differences, many animals would be predicated of the species, for differences are predicated of species. Again, all differences will either be
