Nevertheless, since difference also appears to some to be predicated of species, in reference to what a thing is, we must separate genus from difference, by employing the above-mentioned elements: first, indeed, because genus is of wider predication than difference; next, because genus is more suitable than difference to enunciate, in answer to the question what a thing is; for he who says that man is an animal, developes in a greater degree what man is, than he who terms him pedestrian—and because the difference always signifies the quality of the genus, but the genus not that of the difference; for whoever terms man pedestrian, describes what kind of animal he is; but he who calls him animal, does not describe of what quality is the pedestrian.
Thus then, we must separate the difference from the genus; since however what is musical, so far as it is musical, appears to be scientific, and music to be a certain science, and if what walks is moved by walking, walking to be a certain motion, we must consider in what genus we desire to construct any thing after the manner stated, e. g. if (we wish to show) that science is faith, (we must notice) whether he who is scientifically cognizant, so far as he is so, believes; for it will be evident that science is a certain faith, and the same method (must be used) in other such cases.
Once more, since it is difficult to separate what is always consequent to a certain thing, and does not reciprocate, (so as to show) that it is not genus, it this is consequent to every individual of that, but that not to every individual of this—as quiet to tranquillity, and divisibility to number, but not the contrary, (as not every thing divisible is number, neither (all) quiet, tranquillity,)—(the disputant) must employ this place, as if genus were that which is always consequent, when the other does not reciprocate; but if another proposes (this argument), it must not be admitted in all cases. The objection to it is, that non-entity is consequent to every thing generated, (for what is being generated, is not,) and
