[234] Topic. V. v. p. 134, b. 5-p. 135, a. 5. For the fourth head (d.), no corresponding error is assigned. It should be noted that the illustration given of it, and remarked upon at the foot of the last page, is repeated for the concluding head of the list.
In case the respondent should enunciate his proprium in any one of the above defective ways, you will thus know where to find objections against him. But, if you undertake yourself to enunciate a proprium, you will avoid laying yourself open to the objections, by discriminating under which of these heads you intend to affirm it.[235]
[235] Topic. V. v. p. 135, a. 5: ἄλλου μὲν οὖν οὕτως ἀποδιδόντος τὸ ἴδιον ἐπιχειρητέον, αὐτῷ δ’ οὐ δοτέον ἐστὶ ταύτην τὴν ἔνστασιν, ἀλλ’ εὐθὺς τιθέμενον τὸ ἴδιον διοριστέον ὃν τρόπον τίθησι τὸ ἴδιον.
12. Again, the respondent may perhaps affirm as proprium a predicate really identical with the subject, though under a different name. Thus, he may declare to τὸ πρέπον to be a proprium τοῦ καλοῦ: you may then refute him by showing that πρέπον is identical with καλόν. If he is on the negative side, denying A to be a proprium of B on the ground that A is identical with B, you will make out the affirmative against him by showing that A is not identical with B, but only co-extensive and reciprocating therewith. Thus, you may show that animated substance is not identical with animal, but a proprium of animal.[236]
[236] Ibid. a. 11-19.
13. Where the subject is homœomeric, the respondent may declare as proprium of the whole what cannot be truly affirmed as proprium of a part separately; or he may declare as proprium of a part separately what cannot be truly declared as proprium of the whole. In either case, you have a plausible argument for refuting him; but your refutation will not be always conclusive, because there are various cases in which what is true of each homœomeric part is not true of the whole; and vice versâ. If your position in the debate is affirmative, you will select as illustration some case in which what is by nature true of the whole is also true of each separate part: e.g., The earth as a whole, and each of its parts, tend by nature downwards. This is a proprium of the earth.[237]
[237] Topic. V. v. p. 135, a. 20-b. 6.
14. Respecting Opposita, there are different loci for different varieties.
a. Contraria. — Suppose the respondent to affirm A as proprium of B: you will examine whether the contrary of A is proprium of the contrary of B. If it be not, then neither is A proprium of B. Thus, if best is not a proprium of justice, neither can worst be a proprium of injustice. If the respondent is on the negative side, you may prove the affirmative against him by showing that the contrary of the alleged proprium is a proprium of the contrary of the alleged subject.[238]
[238] Ibid. vi. p. 135, b. 7-16.