[12] Ibid. p. 100, a. 31-p. 101, a. 16; Soph. El. i. p. 164, a. 20-b. 21.
One would suppose that the relation between the pseudo-didactic and the didactic syllogism, was the same as that between the pseudo-dialectic and the dialectic; so that, if the pseudo-dialectic deserved to be called sophistic or eristic, the pseudo-didactic would deserve these appellations also; especially, since the formal conditions of the syllogism are alike for both. This Aristotle does not admit, but draws instead a remarkable distinction. The Sophist (he says) is a dishonest man, making it his professional purpose to deceive; the pseudo-graphic man of science is honest always, though sometimes mistaken. So long as the pseudo-graphic syllogism keeps within the limits belonging to its own special science, it may be false, since the geometer may be deceived even in his own science geometry,[13] but it cannot be sophistic or eristic; yet, whenever it transgresses those limits, even though it be true and though it solves the problem proposed, it deserves to be called by those two epithets. Thus, there were two distinct methods proposed for the quadrature of the circle — one by Hippokrates, on geometrical principles, the other by Bryson, upon principles extra-geometrical. Both demonstrations were false and unsuccessful; yet that of Hippokrates was not sophistic or eristic, because he kept within the sphere of geometry; while that of Bryson was so, because it travelled out of geometry. Nay more, this last would have been equally sophistic and eristic, and on the same ground, even if it had succeeded in solving the problem.[14] If indeed the pseudo-graphic syllogism be invalid in form, it must be considered as sophistic, even though within the proper scientific limits as to matter; but, if it be correct in form and within these same limits, then, however untrue its premisses may be, it is to be regarded as not sophistic or eristic.[15]
[13] Topic. V. iv. p. 132, a. 32.
[14] Soph. El. xi. p. 171, b. 12-20: τὰ γὰρ ψευδογραφήματα οὐκ ἐριστικά (κατὰ γὰρ τὰ ὑπὸ τὴν τέχνην οἱ παραλογισμοί), οὐδέ γ’ εἴ τί ἐστι ψευδογράφημα περὶ ἀληθές, οἷον τὸ Ἱπποκράτους ἢ ὁ τετραγωνισμὸς ὁ διὰ τῶν μηνίσκων. ἀλλ’ ὡς Βρύσων ἐτετραγώνιζε τὸν κύκλον, εἰ καὶ τετραγωνίζεται ὁ κύκλος, ἀλλ’ ὅτι οὐ κατὰ τὸ πρᾶγμα, διὰ τοῦτο σοφιστικός. Also p. 172, a. 1-8.
[15] Ibid. xi. p. 171, b. 19-20. Compare Topic. VIII. xi. p. 161, a. 33: δεῖ δὲ τὸν καλῶς μεταβιβάζοντα διαλεκτικῶς καὶ μὴ ἐριστικῶς μεταβιβάζειν, καθάπερ τὸν γεωμέτρην γεωμετρικῶς, ἄν τε ψεῦδος ἄν τ’ ἀληθὲς ᾖ τὸ συμπεραινόμενον. Also Topic. VIII. xii. p. 162, b. 10.
Such is the test whereby Aristotle distinguishes the sophistication of the didactic process from the legitimate working of that process. Now this same test cannot be applied to Dialectic, which has no appropriate or exclusive specialty of matters, but deals with Omne Scibile, universally and indiscriminately. Aristotle therefore puts the analogy in another way. Both in Didactic and in Dialectic the Sophist is one who sins against the fundamental conditions of the task which he undertakes; these conditions being, that in Didactic he shall confine himself to the matters and premisses of a given science, — in Dialectic, to matters probable of whatever kind they may be. Transgression of these conditions constitutes unfair and dishonest manœuvre, whether of teacher or questioner; like breach of the regulations on the part of competitors, bent on victory at all price, in the Olympic games. Aristotle ranks this dishonesty as a species, under the name of Sophistic or Eristic, admitting of being analysed and defined;[16] and his treatise on Sophistical Refutations is intended to describe and illustrate the Loci belonging to it, and contributing to its purpose.[17]
[16] Soph. El. xi. p. 171, b. 22: ὥσπερ γὰρ ἡ ἐν ἀγῶνι ἀδικία εἶδός τι ἔχει καὶ ἔστιν ἀδικομαχία τις, οὕτως ἐν ἀντιλογίᾳ ἀδικομαχία ἡ ἐριστική ἐστιν· ἐκεῖ τε γὰρ οἱ πάντως νικᾶν προαιρούμενοι πάντων ἅπτονται, καὶ ἐνταῦθα οἱ ἐριστικοί.
[17] Soph. El. ix. p. 170, a. 34: δῆλον οὖν ὅτι οὐ πάντων τῶν ἔλεγχων ἀλλὰ τῶν παρὰ τὴν διαλεκτικὴν ληπτέον τοὺς τόπους.
Fallacious dialectical refutation being thus referred altogether to dishonesty of purpose (either contentious or profit-seeking) and being assumed as unknown in fair dialectical debate, we have to see by what characteristic Aristotle discriminates fallacious premisses from fair and admissible premisses. Dialectic (he tells us) has for its appropriate matter probable premisses — beliefs accredited either by the multitude or by a wise few. But (he goes on to say) not everything which appears probable is really probable. Nothing that is really probable is a mere superficial fancy; wherever this last is the case, the probabilia are apparent only and not real; they have the character of falsehood stamped upon them, so as to be immediately manifest and obvious, even to persons of very narrow intelligence. It is such apparent probabilia as these, which make up the premisses of eristic or sophistic discourse, and upon which the sophistical or fallacious refutations turn.[18]
[18] Topic. I. i. p. 100, b. 23: ἐριστικὸς δ’ ἔστι συλλογισμὸς ὁ ἐκ φαινομένων ἐνδόξων μὴ ὄντων δέ, καὶ ὁ ἐξ ἐνδόξων ἢ φαινομένων ἐνδόξων φαινόμενος. οὐ γὰρ πᾶν τὸ φαινόμενον ἔνδοξον, καὶ ἔστιν ἔνδοξον. οὐθὲν γὰρ τῶν λεγομένων ἐνδόξων ἐπιπόλαιον ἔχει παντελῶς τὴν φαντασίαν, καθάπερ περὶ τὰς τῶν ἐριστικῶν λόγων ἀρχὰς συμβέβηκεν ἔχειν· παραχρῆμα γὰρ καὶ ὡς ἐπὶ τὸ πολύ τοῖς καὶ μικρὰ συνορᾶν δυναμένοις κατάδηλος ἐν αὐτοῖς ἡ τοῦ ψεύδους ἐστὶ φύσις. Compare Soph. El. ii. p. 165, b. 7.