the genus. This however is the same thing with not placing it in the nearest genus, for he who places it in the nearest, has mentioned all the superior, since all the superior genera are predicated of the inferior. Hence, it must either be placed in the nearest genus, or he must add all the differences, through which the nearest genus is defined, to the superior genus; for thus he will have omitted nothing, but instead of a name, will have mentioned the inferior genus, in the definition. Whoever, on the other hand, speaks of the superior genus alone, does not mention also the inferior genus, for the one who calls a thing a plant, does not state it to be a tree.
Chapter 6
Again, we must in like manner consider with regard to differences, whether those of genus are introduced, for unless a person defines by the proper differences of a thing, or altogether asserts what can be the differences of nothing, as animal or substance, he evidently does not define, since the things stated are not the differences of any thing. Observe also, whether any thing is divided oppositely to the difference stated, for if there is not, what is stated will evidently not be the difference of genus, since every genus is divided by differences oppositely divided, as animal by the pedestrian and winged, by the aquatic and biped. Or if indeed there is an oppositely divided difference, which however is not verified of the genus, since evidently neither would be the difference of genus, as all oppositely divided differences are verified of their proper genus. Likewise, if it is indeed verified, but (the difference) when added to genus does not produce species, since it is evident that this would not be the specific difference of genus, as every specific difference united with genus produces species; but if this be not the
