[190] Ibid. a. 26-29.
[191] Topic. IV. v. p. 126, a. 30-b. 6: ὑπόληψις
The general drift of Aristotle is here illustrated better by taking the thief separately, apart from the other two. But we must notice here the proof of his temper or judgment concerning the persons called Sophists, when we find him grouping them in the bunch of ψεκτὰ and φευκτὰ along with thieves. The majority of his uninstructed contemporaries would probably have agreed in this judgment, but they would certainly have enrolled Aristotle himself among the Sophists thus depreciated.
Again, you may detect in the thesis sometimes the mistake of putting under one genus a species which properly comes under two genera conjointly, not subalternate one to the other; sometimes, the mistake of predicating the genus as a differentia, or the differentia as a genus.[192] Sometimes, also, the subject in which the attribute or affection resides is predicated as if it were the genus of such affection; or, è converso, the attribute or affection is predicated as the genus of the subject wherein it resides; e.g., when breath or wind, which is really a movement of air, is affirmed to be air put in motion, and thus constituted as a species under the genus air; or when snow is declared to be water congelated; or mud, to be earth mixed with moisture.[193] In none of these cases is the predicate a true genus; for it cannot be always affirmed of the subject.
[192] Ibid. b. 7-33.
[193] Ibid. b. 34-p. 127, a. 19.
Or perhaps the predicate affirmed as genus may be no genus at all; for nothing can be a genus unless there are species contained under it; e.g., if the thesis declare white to be a genus, this may be impugned, because white objects do not differ in specie from each other. Or a mere universal predicate (such as Ens or Unum) may be put forward as a genus or differentia; or a simple concomitant attribute, or an equivocal term, may be so put forward.[194]
[194] Topic. IV. vi. p. 127, a. 20-b. 7.
Perhaps it may happen that the subject (species) and the predicate (genus) of the thesis may each have a contrary term; and that in each pair of contrary terms one may be better, the other worse. If, in that case, the better species be referred to the worse genus, or vice versâ, this will render the thesis assailable. Or perhaps the species may be fit to be referred equally to both the contrary genera; in which case, if the thesis should refer it to the worse of the two, that will be a ground of objection. Thus, if the soul be referred to the genus mobile, you are at liberty to object that it is equally referable to the genus stabile: and that, as the latter is the better of the two, it ought to be referred to the better in preference to the worse.[195]
[195] Ibid. b. 8-17.