neither subaltern genera, nor both under the same genus, what is assigned will not be a genus.
We must observe too the genus of the assigned genus, and so always the superior genus, whether all things are predicated of the species, and whether they are so in reply to what a thing is, for all superior genera must be predicated of species, in respect to what a thing is; if then there is any where a discrepancy, what is assigned, is evidently not the genus. Again, whether the genus partakes of the species, either itself, or any of the superior genera, as the superior (genus) partakes of none of the inferior. The subverter must use what we have said, but for the supporter it will be sufficient (if the proposed genus is admitted present with the species, but it is doubtful whether it is present with genus) to show that some one of the superior genera is predicated of species, in reference to what a thing is. For if one thing is predicated in reference to what a thing is, all, both above and below this, if they are predicated of species, will be so predicated in reference to what a thing is, so that the assigned genus also is predicated in reference to the same. But that if one is predicated in reference to what a thing is, all the rest will be so, if they are predicated, must be assumed from induction: nevertheless, if it is doubted whether the assigned genus is simply inherent, it is not enough to show that any of the superior genera is predicated of species, in respect to what a thing is, e.g. if some one gave lation, as the genus of walking, it is not sufficient to show that walking is motion, in order to prove that it is lation, since there are other motions also, but we must prove besides, that walking partakes of none of those in the same division, except lation. For it is necessary that the participant of genus, should also participate of some one species, according to the first division; if then walking, neither partakes of increase, nor of diminution, nor of the other motions, it clearly partakes of lation, so that lation would be the genus of walking.
Again, in those where the assigned species is predicated as genus, observe whether the assigned genus also is predicated of the same things of which species is, in reference to what a thing is,
