Alexander remarks (Schol. p. 264, b. 23, Br.) that πρόβλημα here means, not the interrogation, but τὸ ὡρισμένον ἤδη καὶ κείμενον — οὗ προΐσταταί τις, ὅν ὁ διαλεκτικὸς ἐλέγχειν ἐπιχειρεῖ.
[77] Topic. II. i. p. 109, a. 8: διὰ τὸ μᾶλλον τὰς θέσεις κομίζειν ἐν τῷ ὑπάρχειν ἢ μή, τοὺς δὲ διαλεγομένους ἀνασκευάζειν.
[78] Alexander ap. Schol. p. 264, a. 27, Br.: ὅτι δὲ οἰκειότερον τῷ διαλεκτικῷ τὸ ἀνασκευάζειν τοῦ κατασκευάζειν, ἐν τῷ πρώτῳ τῶν ἐπιγραφομένων Εὐδημείων Ἀναλυτικῶν (ἐπιγράφεται δὲ αὐτὸ καὶ Εὐδήμου ὑπὲρ τῶν Ἀναλυτικῶν) οὕτως λέγεται, ὅτι ὁ διαλεκτικὸς ἃ μὲν κατασκευάζει μικρά ἐστι, τὸ δὲ πολὺ τῆς δυνάμεως αὐτοῦ πρὸς τὸ ἀναιρεῖν τι ἐστίν.
Aristotle takes the four heads — Accident, Genus, Proprium, and Definition, in the order here enumerated. The thesis of which the predicate is enunciated as Accident, affirms the least, is easiest to defend, and hardest to upset.[79] When we enunciate Genus or Proprium, we affirm, not merely that the predicate belongs to the subject (which is all that is affirmed in the case of Accident), but, also something more — that it belongs to the subject in a certain manner and relation. And when we enunciate Definition, we affirm all this and something reaching yet farther — that it declares the whole essence of the definitum, and is convertible therewith. Accordingly, the thesis of Definition, affirming as it does so very much, presents the most points of attack and is by far the hardest to defend.[80] Next in point of difficulty, for the respondent, comes the Proprium.
[79] Topic. VII. v. p. 155, a. 27: ῥᾷστον δὲ πάντων κατασκευάσαι τὸ συμβεβηκός — ἀνασκευάζειν δὲ χαλεπώτατον τὸ συμβεβηκός, ὅτι ἐλάχιστα ἐν αὐτῷ δέδοται· οὐ γὰρ προσσημαίνει ἐν τῷ συμβεβηκότι πῶς ὑπάρχει, ὥστ’ ἐπὶ μὲν τῶν ἄλλων διχῶς ἔστιν ἀνελεῖν, ἢ δείξαντα ὅτι οὐχ ὑπάρχει ἢ ὅτι οὐχ οὕτως ὑπαρχει, ἐπὶ δὲ τοῦ συμβεβηκότος οὐκ ἔστιν ἀνελεῖν ἀλλ’ ἢ δείξαντα ὅτι οὐχ ὑπάρχει.
[80] Topic. VII. v. p. 155, a. 3. πάντων ῥᾷστον ὅρον ἀνασκευάσαι· πλεῖστα γὰρ ἐν αὐτῷ τὰ δεδομένα πολλῶν εἰρημένων. a. 23: τῶν δ’ ἄλλων τὸ ἴδιον μάλιστα τοιοῦτον.
Beginning thus with the thesis enunciating Accident, Aristotle enumerates no less than thirty-seven distinct loci or argumentative points of view bearing upon it. Most of them suggest modes of assailing the thesis; but there are also occasionally intimations to the respondent how he may best defend himself. In this numerous list there are indeed some items repetitions of each other, or at least not easily distinguishable.[81] As it would be tedious to enumerate them all, I shall select some of the most marked and illustrative.
[81] Aristotle himself admits the repetition in some cases, Topic. II. ii. p. 110, a. 12: the fourth locus is identical substantially with the second locus.
Theophrastus distinguished παράγγελμα as the general precept, from τόπος or locus, as any proposition specially applying the precept to a particular case (Schol. p. 264, b. 38).
1. The respondent has enunciated a certain predicate as belonging in the way of accident, to a given subject. Perhaps it may belong to the subject; yet not as accident, but under some one of the other three Predicables. Perhaps he may have enunciated (either by explicit discrimination, or at least by implication contained in his phraseology) the genus as if it were an accident, — an error not unfrequently committed.[82] Thus, if he has said, To be a colour is an accident of white, he has affirmed explicitly the genus as if it were an accident. And he has affirmed the same by implication, if he has said, White (or whiteness) is coloured. For this is a form of words not proper for the affirmation of a genus respecting its species, in which case the genus itself ought to stand as a literal predicate (White is a colour), and not to be replaced by one of its derivatives (White is coloured). Nor can the proposition be intended to be taken as affirming either proprium or definition; for in both these the predicate would reciprocate and be co-extensive with the subject, whereas in the present case there are obviously many other subjects of which it may be predicated that they are coloured.[83] In saying, White is coloured, the respondent cannot mean to affirm either genus, proprium, or definition; therefore he must mean to affirm accident. The assailant will show that this is erroneous.