421Ibid. b. 30-39. οἶδε δὲ τὴν λύσιν ὁ εἰδὼς ὅτι παρὰ τοῦτο ὁ λόγος — οὐ γὰρ ἀπόχρη τὸ ἐνστῆναι, οὔδ’ ἂν ψεῦδος ᾖ τὸ ἀναιρούμενον, ἀλλὰ καὶ διότι ψεῦδος ἀποδεικτέον·οὕτω γὰρ ἂν εἴη φανερὸν πότερον προορῶν τι ἢ οὒ ποιεῖται τὴν ἔνστασιν.
421Ibid. b. 30-39. οἶδε δὲ τὴν λύσιν ὁ εἰδὼς ὅτι παρὰ τοῦτο ὁ λόγος — οὐ γὰρ ἀπόχρη τὸ ἐνστῆναι, οὔδ’ ἂν ψεῦδος ᾖ τὸ ἀναιρούμενον, ἀλλὰ καὶ διότι ψεῦδος ἀποδεικτέον·οὕτω γὰρ ἂν εἴη φανερὸν πότερον προορῶν τι ἢ οὒ ποιεῖται τὴν ἔνστασιν.
This last-mentioned proceeding — refutation of that premiss upon which your false conclusion in its full bearing really turns — is the only regular, valid, and complete objection whereby the respondent can stop out your syllogistic approaches. There are indeed three other modes of objection to which he may resort; but these are all either inconclusive or unfair. He may turn his objection against you personally; and, without refuting any of your premisses, he may thus perplex and confuse you, so that you are disqualified from pursuing the thread of your questions. Or he may turn his objections against portions of your questions; not refuting any one of your premisses, but showing that, as they stand, they are insufficient to warrant the conclusion which you seek to establish; when, if you are master of your subject, and retain your calmness, you will at once supply the deficiency by putting additional questions, so that his objection thus vanishes. Or, lastly, he may multiply irrelevant objections against time, for the purpose of prolonging the discussion and tiring you out.422Of these four modes of objection open to the respondent the first is the only one truly valid and conclusive; the three others are obstructions either surmountable or unfair, and the last is the most discreditable of all.423
422Ibid. p. 161, a. 1-12: ἔστι δὲ λόγον κωλῦσαι συμπεράνασθαι τετραχῶς. ἢ γὰρ ἀνελόντα παρ’ ὃ γίνεται τὸ ψεῦδος. ἢ πρὸς τὸν ἐρωτῶντα ἔνστασιν εἰπόντα· — τρίτον δὲ πρὸς τὰ ἠρωτημένα· — τετάρτη δὲ καὶ χειρίστη τῶν ἐνστάσεων ἡ πρὸς τὸν χρόνον.
422Ibid. p. 161, a. 1-12: ἔστι δὲ λόγον κωλῦσαι συμπεράνασθαι τετραχῶς. ἢ γὰρ ἀνελόντα παρ’ ὃ γίνεται τὸ ψεῦδος. ἢ πρὸς τὸν ἐρωτῶντα ἔνστασιν εἰπόντα· — τρίτον δὲ πρὸς τὰ ἠρωτημένα· — τετάρτη δὲ καὶ χειρίστη τῶν ἐνστάσεων ἡ πρὸς τὸν χρόνον.
423Ibid. a. 13-15: αἱ μὲν οὖν ἐνστάσεις, καθάπερ εἴπαμεν, τετραχῶς γίνονται· λύσις δ’ ἐστὶ τῶν εἰρημένων ἡ πρώτη μόνον, αἱ δὲ λοιπαὶ κωλύσεις τινὲς καὶ ἐμποδισμοὶ τῶν συμπερασμάτων.
423Ibid. a. 13-15: αἱ μὲν οὖν ἐνστάσεις, καθάπερ εἴπαμεν, τετραχῶς γίνονται· λύσις δ’ ἐστὶ τῶν εἰρημένων ἡ πρώτη μόνον, αἱ δὲ λοιπαὶ κωλύσεις τινὲς καὶ ἐμποδισμοὶ τῶν συμπερασμάτων.
To blame the argumentative procedure and to blame the questioner are two distinct things. Perhaps your manner of conducting the interrogation, preparatory to your final syllogism, may be open to censure; yet nevertheless you the questioner may deserve no censure; for it may be the respondent’s fault, not yours. He may refuse to grant the very premisses which are essential to the good conduct of your case; he may resort to perverse evasions and contradictions for the mere purpose ofthwarting you; so that you are forced to adapt yourself to his unworthy manœuvres rather than to aim at the thesis itself. Dialectic cannot be well conducted unless both the partners do their duty to the common purpose; the bad conduct of your respondent puts you out, and the dialectic presently degenerates on both sides into angry contention.424Apart from this, too, it must be remembered that the express purpose of Dialectic is not to teach, but to search and test consequences and to exercise the intellect of both parties. Accordingly you are not always restricted to true syllogistic premisses and conclusions. You are allowed to resort occasionally to false premisses and false conclusions; for, if what the respondent advances be true, you have no means of refuting it except by falsehood; and, if what he advances be false, the best way of refuting it may be through some other falsehood.425You render service to him by doing so; for, since his beliefs are contrary to truth, if the dialogue is confined to his beliefs, the result may perhaps contribute to persuade him, but it will not instruct or profit him.426It is your business to bring him round and emancipate him from these erroneous beliefs; but you must accomplish this in a manner truly dialectical, and not contentious; whether you proceed by true or by false conclusions.427If you on your side, indeed, put questions in a contentious spirit, it is you that are to blame. But often the respondent is most to blame, when he refuses to grant what he thinks probable, and when he does not apprehend what you really intend to ask.428He is sometimes also to blame for granting what he ought to refuse; such asPetitio Principiior Affirmation of Contraries. It is often difficult to distinguish what questions involvePetitio Principiior Affirmation of Contraries: they are asked and granted without either party being aware, and the like mistake is committed by men in private talk, not merely in formal dialogue. When this happens, the argument will inevitably be a bad one; but the fault is with therespondent who, having before refused what he ought to have granted, now grants what he ought to refuse.429
424Topic. VIII. xi. p. 161, a. 16-24. δυσκολαίνοντες οὖν ἀγωνιστικὰς καὶ οὐ διαλεκτικὰς ποιοῦνται τὰς διατριβάς. a. 37: φαῦλος κοινωνὸς ὁ ἐμποδίζων τὸ κοινὸν ἔργον.
424Topic. VIII. xi. p. 161, a. 16-24. δυσκολαίνοντες οὖν ἀγωνιστικὰς καὶ οὐ διαλεκτικὰς ποιοῦνται τὰς διατριβάς. a. 37: φαῦλος κοινωνὸς ὁ ἐμποδίζων τὸ κοινὸν ἔργον.
425Ibid. a. 24-31: ἔτι δ’ ἐπεὶ γυμνασίας καὶ πείρας χάριν ἀλλ’ οὐ διδασκαλίας οἱ τοιοῦτοι τῶν λόγων, δῆλον ὡς οὐ μόνον τἀληθῆ συλλογιστέον ἀλλὰ καὶ ψεῦδος, οὐδὲ δι’ ἀληθῶν ἀεὶ ἀλλ’ ἐνίοτε καὶ ψευδῶν. πολλάκις γὰρ ἀληθοῦς τεθέντος ἀναιρεῖν ἀνάγκη τὸν διαλεγόμενον, ὥστε προτατέον τὰ ψευδῆ. ἐνίοτε δὲ καὶ ψεύδους τεθέντος ἀναιρετέον διὰ ψευδῶν.
425Ibid. a. 24-31: ἔτι δ’ ἐπεὶ γυμνασίας καὶ πείρας χάριν ἀλλ’ οὐ διδασκαλίας οἱ τοιοῦτοι τῶν λόγων, δῆλον ὡς οὐ μόνον τἀληθῆ συλλογιστέον ἀλλὰ καὶ ψεῦδος, οὐδὲ δι’ ἀληθῶν ἀεὶ ἀλλ’ ἐνίοτε καὶ ψευδῶν. πολλάκις γὰρ ἀληθοῦς τεθέντος ἀναιρεῖν ἀνάγκη τὸν διαλεγόμενον, ὥστε προτατέον τὰ ψευδῆ. ἐνίοτε δὲ καὶ ψεύδους τεθέντος ἀναιρετέον διὰ ψευδῶν.
426Ibid. a. 30: οὐδὲν γὰρ κωλύει τινὶ δοκεῖν τὰ μὴ ὄντα μᾶλλον τῶν ἀληθῶν, ὥστ’ ἐκ τῶν ἐκείνῳ δοκούντων τοῦ λόγου γενομένου μᾶλλον ἔσται πεπεισμένος ἢ ὠφελημένος.
426Ibid. a. 30: οὐδὲν γὰρ κωλύει τινὶ δοκεῖν τὰ μὴ ὄντα μᾶλλον τῶν ἀληθῶν, ὥστ’ ἐκ τῶν ἐκείνῳ δοκούντων τοῦ λόγου γενομένου μᾶλλον ἔσται πεπεισμένος ἢ ὠφελημένος.
427Ibid. a. 33: δεῖ δὲ τὸν καλῶς μεταβιβάζοντα διαλεκτικῶς καὶ μὴ ἐριστικῶς μεταβιβάζειν. About τὸ μεταβιβάζειν, compare Topica, I. ii. p. 101, a. 23.
427Ibid. a. 33: δεῖ δὲ τὸν καλῶς μεταβιβάζοντα διαλεκτικῶς καὶ μὴ ἐριστικῶς μεταβιβάζειν. About τὸ μεταβιβάζειν, compare Topica, I. ii. p. 101, a. 23.
428Ibid. b. 2: ὅ τε γὰρ ἐριστικῶς ἐρωτῶν φαύλως διαλέγεται, ὅ τ’ ἐν τῷ ἀποκρίνεσθαι μὴ διδοὺς τὰ φαινόμενον μηδ’ ἐκδεχόμενος ὅ τί ποτε βούλεται ὁ ἐρωτῶν πυθέσθαι.
428Ibid. b. 2: ὅ τε γὰρ ἐριστικῶς ἐρωτῶν φαύλως διαλέγεται, ὅ τ’ ἐν τῷ ἀποκρίνεσθαι μὴ διδοὺς τὰ φαινόμενον μηδ’ ἐκδεχόμενος ὅ τί ποτε βούλεται ὁ ἐρωτῶν πυθέσθαι.
429Topic. VIII. xi. p. 161, b. 11-18: ἐπεὶ δ’ ἐστὶν ἀδιόριστον πότε τἀναντία καὶ πότε τὰ ἐν ἀρχῇ λαμβάνουσιν οἱ ἄνθρωποι (πολλάκις γὰρ καθ’ αὑτοὺς λέγοντες τἀναντία λέγουσι, καὶ ἀνανεύσαντες πρότερον διδόασιν ὕστερον· διόπερ ἐρωτώμενοι τἀναντία καὶ τὸ ἐν ἀρχῇ πολλάκις ὑπακούουσιν) — ἀνάγκη φαύλους γίνεσθαι τοὺς λόγους· αἴτιος δ’ ὁ ἀποκρινόμενος, τὰ μὲν οὐ διδούς, τὰ δὲ τοιαῦτα διδούς.This passage is not very clear.
429Topic. VIII. xi. p. 161, b. 11-18: ἐπεὶ δ’ ἐστὶν ἀδιόριστον πότε τἀναντία καὶ πότε τὰ ἐν ἀρχῇ λαμβάνουσιν οἱ ἄνθρωποι (πολλάκις γὰρ καθ’ αὑτοὺς λέγοντες τἀναντία λέγουσι, καὶ ἀνανεύσαντες πρότερον διδόασιν ὕστερον· διόπερ ἐρωτώμενοι τἀναντία καὶ τὸ ἐν ἀρχῇ πολλάκις ὑπακούουσιν) — ἀνάγκη φαύλους γίνεσθαι τοὺς λόγους· αἴτιος δ’ ὁ ἀποκρινόμενος, τὰ μὲν οὐ διδούς, τὰ δὲ τοιαῦτα διδούς.
This passage is not very clear.
Such then are the cases in which the conduct of the dialogue is open to censure, without any fault on your part as questioner. But there are other cases in which the fault is really yours. These are five in number:— (1) When all or most of your questions are so framed as to elicit premisses either false or improbable, so that neither the conclusion which you seek to obtain, nor any other conclusion at all, follows from them; (2) When, from similar defects, the proper conclusion that you seek to obtain cannot be drawn from your premisses; (3) When the proper conclusion would follow, if certain additions were made to your premisses, but such additions are of a character worse than the premisses already obtained, and are even less probable than the conclusion itself; (4) When you have accumulated a superfluous multitude of premisses, so that the proper conclusion does not follow from all of them but from a part of them only (5) When your premisses are more improbable and less trustworthy than the proper conclusion, or when, though true, they are harder and more troublesome to prove than the problem itself.430
430Ibid. b. 19-33: καθ’ αὑτὸν δὲ τῷ λόγῳ πέντε εἰσὶν ἐπιτιμήσεις.
430Ibid. b. 19-33: καθ’ αὑτὸν δὲ τῷ λόγῳ πέντε εἰσὶν ἐπιτιμήσεις.
In regard to the last item, however, the fault may sometimes be in the problem itself rather than in you as questioner. Some problems, being in their own nature hard and not to be settled from probable or plausible data, ought not to be admitted into Dialectic. All that can be required from you as questioner is that you shall know and obtain the most probable premisses that the problem admits: your procedure may be thus in itself blameable, yet it may even deserve praise, having regard to the problem, if this last be very intractable; or it may be in itself praiseworthy, yet blameable in regard to the problem, if the problem admit of being settled by premisses still more probable.431You may even be more blameable, if you obtain your conclusion but obtain it from improbable premisses, than if you failed to obtain it; the premisses required to make it complete being true and probable and not of capital importance, but being refused by the respondent.432However, you ought notto be blamed if you obtain your true and proper conclusion but obtain it through premisses in themselves false; for this is recognized in analytical theory as possible: if the conclusion is false, the premisses (one or both) must be false, but a true conclusion may be drawn from false premisses.433
431Ibid. b. 34-p. 162, a. 3.
431Ibid. b. 34-p. 162, a. 3.
432Ibid. p. 162, a. 3-8.
432Ibid. p. 162, a. 3-8.
433Topic. VIII. xi. p. 162, a. 8-11: τοῖς δὲ διὰ ψευδῶν ἀληθὲς συμπεραινομένοις οὐ δίκαιον ἐπιτιμᾶν — φανερὸν δ’ ἐκ τῶν Ἀναλυτικῶν.
433Topic. VIII. xi. p. 162, a. 8-11: τοῖς δὲ διὰ ψευδῶν ἀληθὲς συμπεραινομένοις οὐ δίκαιον ἐπιτιμᾶν — φανερὸν δ’ ἐκ τῶν Ἀναλυτικῶν.
When you have obtained your premisses and proved a conclusion, these same premisses will not serve as proof of any other proposition separate and independent of the conclusion; such may sometimes seem to be the case, but it is a mere sophistical delusion. If your premisses are both of them probable, your conclusion may in some cases be more probable than either.434
434Ibid. a.12-24.Aristotle here introduces four definitions of terms, which are useful in regard to his thoughts but have no great pertinence in the place where they occur: ἔστι δὲφιλοσόφημαμὲν συλλογισμὸς ἀποδεικτικός,ἐπιχείρημαδὲ συλλογισμὸς διαλεκτικός,σόφισμαδὲ συλλογισμὸς ἐριστικός,ἀπόρημαδὲ συλλογισμὸς διαλεκτικὸς ἀντιφάσεως.
434Ibid. a.12-24.
Aristotle here introduces four definitions of terms, which are useful in regard to his thoughts but have no great pertinence in the place where they occur: ἔστι δὲφιλοσόφημαμὲν συλλογισμὸς ἀποδεικτικός,ἐπιχείρημαδὲ συλλογισμὸς διαλεκτικός,σόφισμαδὲ συλλογισμὸς ἐριστικός,ἀπόρημαδὲ συλλογισμὸς διαλεκτικὸς ἀντιφάσεως.
One other matter yet remains in which your procedure as questioner may be blameable. The premisses through which you prove your conclusion may be long and unnecessarily multiplied; the conclusion may be such that you ought to have obtained it through fewer, yet equally pertinent premisses.435
435Ibid. a. 24-34.The example whereby Aristotle illustrates this position is obscure and difficult to follow. It is borrowed from the Platonic theory of Ideas. The point which you are supposed to be anxious to prove is, that one opinion is more opinion than another (ὅτι ἐστὶ δόξα μᾶλλον ἑτέρα ἑτέρας). To prove it you ask as premisses: (1) That the Idea of every class of things is more that thing than any one among the particulars of the class; (2) That there is an Idea ofmatter of opinion, and that this Idea is more opinion than any one of the particular matters of opinion. If this Idea is more opinion, it must also be more true and accurate than any particular matter of opinion. And it is this last conclusion that Aristotle seems to indicate as the conclusion to be proved: ὥστε αὑτὴ ἡ δόξα ἀκριβεστέρα ἐστίν (a. 32).As I understand it, Aristotle supposes that the doctrine which you are here refuting is, that all ἔνδοξα are on an equal footing as to truth and accuracy; and that the doctrine which you are proving against it is, that one ἔνδοξον is more true and accurate than another. If you attempt to prove this last by invoking the Platonic theory of Ideas, you will introduce premisses far-fetched and unnecessary, even if true; whereas you might prove your conclusion from premisses easier and more obvious.The fault is (he says) that such roundabout procedure puts out of sight the real ground of the proof: τίς δὲ ἡ μοχθηρία; ἢ ὅτι ποιεῖ, παρ’ ὃ ὁ λόγος, λανθάνειν τὸ αἴτιον (a. 33). The dubitative and problematical form here is remarkable. How would Aristotle himself have proved the above conclusion? By Induction? He does not tell us.
435Ibid. a. 24-34.
The example whereby Aristotle illustrates this position is obscure and difficult to follow. It is borrowed from the Platonic theory of Ideas. The point which you are supposed to be anxious to prove is, that one opinion is more opinion than another (ὅτι ἐστὶ δόξα μᾶλλον ἑτέρα ἑτέρας). To prove it you ask as premisses: (1) That the Idea of every class of things is more that thing than any one among the particulars of the class; (2) That there is an Idea ofmatter of opinion, and that this Idea is more opinion than any one of the particular matters of opinion. If this Idea is more opinion, it must also be more true and accurate than any particular matter of opinion. And it is this last conclusion that Aristotle seems to indicate as the conclusion to be proved: ὥστε αὑτὴ ἡ δόξα ἀκριβεστέρα ἐστίν (a. 32).
As I understand it, Aristotle supposes that the doctrine which you are here refuting is, that all ἔνδοξα are on an equal footing as to truth and accuracy; and that the doctrine which you are proving against it is, that one ἔνδοξον is more true and accurate than another. If you attempt to prove this last by invoking the Platonic theory of Ideas, you will introduce premisses far-fetched and unnecessary, even if true; whereas you might prove your conclusion from premisses easier and more obvious.
The fault is (he says) that such roundabout procedure puts out of sight the real ground of the proof: τίς δὲ ἡ μοχθηρία; ἢ ὅτι ποιεῖ, παρ’ ὃ ὁ λόγος, λανθάνειν τὸ αἴτιον (a. 33). The dubitative and problematical form here is remarkable. How would Aristotle himself have proved the above conclusion? By Induction? He does not tell us.
The cases in which your argument will carry the clearest evidence, impressing itself even on the most vulgar minds, are those in which you obtain such premisses as will enable you to draw your final conclusion without asking any farther concessions. But this will rarely happen. Even after you have obtained all the premisses substantially necessary to your finalconclusion, you will generally be forced to draw out two or more prosyllogisms or preliminary syllogisms, and to ask the assent of the respondent to these, before you can venture to enunciate the final conclusion. This second grade of evidence is however sufficient, even if the premisses fall short of the highest probability.436
436Topic. VIII. xii. p. 162, a. 35-b. 2.
436Topic. VIII. xii. p. 162, a. 35-b. 2.
On the other hand, your argument may deserve to be pronounced false on four distinct grounds:— (1) If your syllogism appears to prove the conclusion but does not really prove it, being then aneristicorcontentioussyllogism; (2) If the conclusion be good but notrelevantto the thesis, which is most likely to happen where you employReductio ad Impossible; (3) If your conclusion though valid and even relevant, is not founded on the premisses andprincipiaappropriate to the thesis; (4) If your premisses are false, even though the conclusion in itself may prove true, since it has already been said that a true conclusion may sometimes be obtained from false premisses.437
437Ibid. b. 3-15: ψευδὴς δὲ λόγος καλεῖται τετραχῶς, &c.
437Ibid. b. 3-15: ψευδὴς δὲ λόγος καλεῖται τετραχῶς, &c.
Falsehood in your argument will be rather your own fault than that of your argument, especially if you yourself are not aware of its falsehood. Indeed, there are some false arguments which are more valuable in Dialectic than many true ones; where, for example, from highly probable premisses you refute some recognized truth. Such an argument is sure to serve as a demonstration of other truths; at the very least, it shows that some one of the propositions concerned is altogether untrue.438On the other hand, if you prove a true conclusion by premisses false and improbable, your argument will be more worthless than many others in which the conclusion is false; from such premisses, indeed, the conclusion may well be really false.439
438Ibid. b. 16-22: τὸ μὲν οὖν ψευδῆ τὸν λόγον εἶναι τοῦ λέγοντος ἁμάρτημα μᾶλλον ἢ τοῦ λόγου, καὶ οὐδὲ τοῦ λέγοντος ἀεὶ τὸ ἁμάρτημα, ἀλλ’ ὅταν λανθάνῃ αὐτόν, ἐπεὶ καθ’ αὑτόνγε πολλῶν ἀληθῶν ἀποδεχόμεθα μᾶλλον, ἂν ἐξ ὅτι μάλιστα δοκούντων ἀναιρῇ τι τῶν ἀληθῶν· τοιοῦτος γὰρ ὢν ἑτέρων ἀληθῶν ἀπόδειξίς ἐστιν· δεῖ γὰρ τῶν κειμένων τι μὴ εἶναι παντελῶς, ὥστ’ ἔσταιτούτουἀπόδειξις.
438Ibid. b. 16-22: τὸ μὲν οὖν ψευδῆ τὸν λόγον εἶναι τοῦ λέγοντος ἁμάρτημα μᾶλλον ἢ τοῦ λόγου, καὶ οὐδὲ τοῦ λέγοντος ἀεὶ τὸ ἁμάρτημα, ἀλλ’ ὅταν λανθάνῃ αὐτόν, ἐπεὶ καθ’ αὑτόνγε πολλῶν ἀληθῶν ἀποδεχόμεθα μᾶλλον, ἂν ἐξ ὅτι μάλιστα δοκούντων ἀναιρῇ τι τῶν ἀληθῶν· τοιοῦτος γὰρ ὢν ἑτέρων ἀληθῶν ἀπόδειξίς ἐστιν· δεῖ γὰρ τῶν κειμένων τι μὴ εἶναι παντελῶς, ὥστ’ ἔσταιτούτουἀπόδειξις.
439Ibid. b. 22-24.
439Ibid. b. 22-24.
In estimating the dialectical value of an argument, therefore, we must first look whether the conclusion is formally valid; next, whether the conclusion is true or false; lastly, what are the premisses from whence it is derived.440For, if it be derived from premisses false yet probable, it has logical or dialecticalvalue; while, if derived from premisses true yet improbable, it has none.441If derived from premisses both false and improbable, it will of course be worthless; either absolutely in itself, or with reference to the thesis under debate.
440Ibid. b. 24: ὥστε δῆλον ὅτι πρώτη μὲν ἐπίσκεψις λόγου καθ’ αὑτὸν εἰ συμπεραίνεται, δευτέρα δὲ πότερον ἀληθὲς ἢ ψεῦδος· τρίτη δ’ ἐκ ποίων τινῶν.
440Ibid. b. 24: ὥστε δῆλον ὅτι πρώτη μὲν ἐπίσκεψις λόγου καθ’ αὑτὸν εἰ συμπεραίνεται, δευτέρα δὲ πότερον ἀληθὲς ἢ ψεῦδος· τρίτη δ’ ἐκ ποίων τινῶν.
441Topic. VIII. xii. p. 162, b. 27: εἰ μὲν γὰρ ἐκ ψευδῶν ἐνδόξων δέ, λογικός, εἰ δ’ ἐξ ὄντων μὲν ἀδόξων δέ, φαῦλος, &c.
441Topic. VIII. xii. p. 162, b. 27: εἰ μὲν γὰρ ἐκ ψευδῶν ἐνδόξων δέ, λογικός, εἰ δ’ ἐξ ὄντων μὲν ἀδόξων δέ, φαῦλος, &c.
Two faults of questioners in Dialectic are dealt with specially by Aristotle:— (1)Petitio Principii; (2)Petitio Contrariorum. He had touched upon both of them (in the Analytica Priora) as they concerned the demonstrative process, or the proving of truth: he now deals with them as they concern the dialectical process, or the setting out of opinions and probabilities.442
442Ibid. xiii. p. 162, b. 31: τὸ δ’ ἐν ἀρχῇ καὶ τὰ ἐναντία πῶς αἰτεῖται ὁ ἐρωτῶν,κατ’ ἀλήθειανμὲν ἐν τοῖς Ἀναλυτικοῖς (Priora, II. xvi.) εἴρηται,κατὰ δόξανδὲ νῦν λεκτέον.
442Ibid. xiii. p. 162, b. 31: τὸ δ’ ἐν ἀρχῇ καὶ τὰ ἐναντία πῶς αἰτεῖται ὁ ἐρωτῶν,κατ’ ἀλήθειανμὲν ἐν τοῖς Ἀναλυτικοῖς (Priora, II. xvi.) εἴρηται,κατὰ δόξανδὲ νῦν λεκτέον.
Five distinct modes may be enumerated of committing the fault calledPetitio Principii:—
1. You may put as a question the very conclusion which it is incumbent on you to prove, in refutation of the thesis of the respondent. If this is done in explicit terms, your opponent can hardly fail to perceive it; but he possibly may fail, if you substitute an equivalent term or the definition in place of the term.443
443Ibid. b. 34. πρῶτον εἴ τις αὐτὸ τὸ δείκνυσθαι δέον αἰτήσει· τοῦτο δ’ ἐπ’ αὐτοῦ μὲν οὐ ῥᾴδιον λανθάνειν, ἐν δὲ τοῖς συνωνύμοις, καὶ ἐν ὅσοις τὸ ὄνομα καὶ ὁ λόγος τὸ αὐτὸ σημαίνει, μᾶλλον.
443Ibid. b. 34. πρῶτον εἴ τις αὐτὸ τὸ δείκνυσθαι δέον αἰτήσει· τοῦτο δ’ ἐπ’ αὐτοῦ μὲν οὐ ῥᾴδιον λανθάνειν, ἐν δὲ τοῖς συνωνύμοις, καὶ ἐν ὅσοις τὸ ὄνομα καὶ ὁ λόγος τὸ αὐτὸ σημαίνει, μᾶλλον.
2. If the conclusion which you are seeking to prove is a particular one, you may put as a question the universal in which it is comprised. Thus, if you are to prove that the knowledge of Contraries is one and the same, you may put as a question, Is not the knowledge of Opposites one and the same? You are asking the very point which it was your business to show; but you are asking along with it much more besides.444
444Ibid. p. 163, a. 1.
444Ibid. p. 163, a. 1.
3. If you are seeking to prove an universal conclusion,youmay put as a question one of the particulars comprised therein. Thus, if you are to prove that the knowledge of Contraries is one and the same, you may put as a question, Is not the knowledge of white and black, good and evil, or any other pair of particular contraries, one and the same? It was your business to prove this particular, along with many others besides; but you are now asking it as a question separately.445
445Ibid. a. 5.
445Ibid. a. 5.
4. If the conclusion which you are seeking to prove has two terms conjointly, you may put as a question one or the other of these separately. Thus, when you are trying to show that the healing art is knowledge of what is wholesome and unwholesome, you may ask, Is it a knowledge of the wholesome?446
446Ibid. a. 8.
446Ibid. a. 8.
5. Suppose there are two conclusions necessarily implicated with each other, and that it is your business to prove one of them: you may put as a question the other of the two. Thus, if you are seeking to prove that the diagonal is incommensurable with the side, you may put as a question, Is not the side incommensurable with the diagonal?447
447Topic. VIII. xiii. p. 163, a. 10.
447Topic. VIII. xiii. p. 163, a. 10.
There are also five distinct modes ofPetitio Contrariorum:—
1. You may ask the respondent, in plain terms, to grant first the affirmative, next, the negative, of a given proposition.448
448Ibid. a. 14: πρῶτον μὲν γὰρ εἴ τις τὰς ἀντικειμένας αἰτήσαιτο φάσιν καὶ ἀντίφασιν.
448Ibid. a. 14: πρῶτον μὲν γὰρ εἴ τις τὰς ἀντικειμένας αἰτήσαιτο φάσιν καὶ ἀντίφασιν.
2. You may ask him to grant, first, that a given subject is,e.g., good, next, that the same subject is bad.449
449Ibid. a. 16: δεύτερον δὲ τἀναντία κατὰ τὴν ἀντίθεσιν, οἷον ἀγαθὸν καὶ κακὸν ταὐτόν.
449Ibid. a. 16: δεύτερον δὲ τἀναντία κατὰ τὴν ἀντίθεσιν, οἷον ἀγαθὸν καὶ κακὸν ταὐτόν.
3. After he has granted to you the affirmative universally, you may ask him to grant the negative in some particular case under the universal:e.g., after he has granted that the knowledge of Contraries is one and the same, you ask him to grant that the knowledge of wholesome and unwholesome is not one and the same. Or you may proceed by the way of reversing this process.450
450Ibid. a. 17-21.
450Ibid. a. 17-21.
4. You may ask the contrary of that which follows necessarily from the premisses admitted.451
451Ibid. a. 21.
451Ibid. a. 21.
5. Instead of asking the two contraries in plain and direct terms, you may ask the two contraries in different propositions, yet necessarily implicated with the first two.452
452Ibid. a. 22.
452Ibid. a. 22.
There is this difference betweenPetitio Principii, andPetitio Contrariorum: the first has reference to the conclusion which you have to prove, and the wrong procedure involved in it is relative to that conclusion; but in the second the wrong procedure affects only the two propositions themselves and the relation subsisting between them.453
453Ibid. a. 24: διαφέρει δὲ τὸ τἀναντία λαμβάνειν τοῦ ἐν ἀρχῇ, ὅτι τοῦ μέν ἐστιν ἡ ἁμαρτία πρὸς τὸ συμπέρασμα (πρὸς γὰρ ἐκεῖνο βλέποντες τὸ ἐν ἀρχῇ λέγομεν αἰτεῖσθαι), τὰ δ’ ἐναντία ἐστὶν ἐν ταῖς προτάσεσι τῷ ἔχειν πως ταύτας πρὸς ἀλλήλας.
453Ibid. a. 24: διαφέρει δὲ τὸ τἀναντία λαμβάνειν τοῦ ἐν ἀρχῇ, ὅτι τοῦ μέν ἐστιν ἡ ἁμαρτία πρὸς τὸ συμπέρασμα (πρὸς γὰρ ἐκεῖνο βλέποντες τὸ ἐν ἀρχῇ λέγομεν αἰτεῖσθαι), τὰ δ’ ἐναντία ἐστὶν ἐν ταῖς προτάσεσι τῷ ἔχειν πως ταύτας πρὸς ἀλλήλας.
Aristotle now, finally, proceeds to give some general advice for exercise and practice in Dialectic. You ought to accustom yourself to treat arguments by converting the syllogisms of which they consist; that is, by applying to them the treatment of which theReductio ad Absurdumis one case.454You ought to test every thesis by first assuming it to be true, then assuming it to be false, and following out the consequences onboth sides.455When you have hunted out each train of arguments, look out at once for the counter-arguments available against it. This will strengthen your power both as questioner and as respondent. It is indeed an exercise so valuable, that you will do well to go through it by yourself, if you have no companion.456Put the different trains of argument, bearing on the same thesis, into comparison with each other. A wide command of arguments affirmative as well as negative will serve you well both for attack and for defence.457
454Ibid. xiv. p. 163, a. 29: πρὸς δὲ γυμνασίαν καὶ μελέτην τῶν τοιούτων λόγων πρῶτον μὲν ἀντιστρέφειν ἐθίζεσθαι χρὴ τοὺς λόγους. ForConversionof Syllogism, seep. 174.
454Ibid. xiv. p. 163, a. 29: πρὸς δὲ γυμνασίαν καὶ μελέτην τῶν τοιούτων λόγων πρῶτον μὲν ἀντιστρέφειν ἐθίζεσθαι χρὴ τοὺς λόγους. ForConversionof Syllogism, seep. 174.
455Topic. VIII. xiv. p. 163, a. 36: πρὸς ἅπασάν τε θέσιν καὶ ὅτι οὕτως καὶ ὅτι οὐχ οὕτως τὸ ἐπιχείρημα σκεπτέον.
455Topic. VIII. xiv. p. 163, a. 36: πρὸς ἅπασάν τε θέσιν καὶ ὅτι οὕτως καὶ ὅτι οὐχ οὕτως τὸ ἐπιχείρημα σκεπτέον.
456Ibid. b. 3: κἂν πρὸς μηδένα ἄλλον ἔχωμεν, πρὸς αὑτούς.
456Ibid. b. 3: κἂν πρὸς μηδένα ἄλλον ἔχωμεν, πρὸς αὑτούς.
457Ibid. b. 5: τοῦτο γὰρπρός τε τὸ βιάζεσθαιπολλὴν εὐπορίαν ποιεῖ καὶ πρὸς τὸ ἐλέγχειν μεγάλην ἔχει βοήθειαν, ὅταν εὐπορῇ τις καὶ ὅτι οὕτως καὶ ὅτι οὐχ οὕτως· πρὸς τὰ ἐναντία γὰρ συμβαίνει ποιεῖσθαι τὴν φυλακήν.Instead of πρός τε τὸ βιάζεσθαι, ought we not to read here πρός τε τὸ μη βιάζεσθαι, taking this verb in the passive sense? Surely βιάζεσθαι in the active sense gives the same meaning substantially as ἐλέγχειν, which comes afterwards, both of them referring to the assailant or questioner, whereas Aristotle intends here to illustrate the usefulness of the practice tobothparties.
457Ibid. b. 5: τοῦτο γὰρπρός τε τὸ βιάζεσθαιπολλὴν εὐπορίαν ποιεῖ καὶ πρὸς τὸ ἐλέγχειν μεγάλην ἔχει βοήθειαν, ὅταν εὐπορῇ τις καὶ ὅτι οὕτως καὶ ὅτι οὐχ οὕτως· πρὸς τὰ ἐναντία γὰρ συμβαίνει ποιεῖσθαι τὴν φυλακήν.
Instead of πρός τε τὸ βιάζεσθαι, ought we not to read here πρός τε τὸ μη βιάζεσθαι, taking this verb in the passive sense? Surely βιάζεσθαι in the active sense gives the same meaning substantially as ἐλέγχειν, which comes afterwards, both of them referring to the assailant or questioner, whereas Aristotle intends here to illustrate the usefulness of the practice tobothparties.
This same accomplishment will be of use, moreover, for acquisitions even in Science and Philosophy. It is a great step to see and grasp in conjunction the trains of reasoning on both sides of the question; the task that remains — right determination which of the two is the better — becomes much easier. To do this well, however, — to choose the true and to reject the false correctly — there must be conjoined a good natural predisposition. None but those who are well constituted by nature, who have their likings and dislikes well set in regard to each particular conjuncture, can judge correctly what is best and what is worst.458
458Ibid. b. 12-16: δεῖ δὲ πρὸς τὸ τοιοῦτο ὑπάρχειν εὐφυᾶ· καὶ τοῦτ’ ἔστιν ἡ κατ’ ἀλήθειαν εὐφυΐα, τὸ δύνασθαι καλῶς ἑλέσθαι τἀληθὲς καὶ φυγεῖν τὸ ψεῦδος· ὅπερ οἱ πεφυκότες εὖ δύνανται ποιεῖν· εὖ γὰρ φιλοῦντες καὶ μισοῦντες τὸ προσφερόμενον εὖ κρίνουσι τὸ βέλτιστον.
458Ibid. b. 12-16: δεῖ δὲ πρὸς τὸ τοιοῦτο ὑπάρχειν εὐφυᾶ· καὶ τοῦτ’ ἔστιν ἡ κατ’ ἀλήθειαν εὐφυΐα, τὸ δύνασθαι καλῶς ἑλέσθαι τἀληθὲς καὶ φυγεῖν τὸ ψεῦδος· ὅπερ οἱ πεφυκότες εὖ δύνανται ποιεῖν· εὖ γὰρ φιλοῦντες καὶ μισοῦντες τὸ προσφερόμενον εὖ κρίνουσι τὸ βέλτιστον.
In regard to the primary or most universal theses, and to those problems which are most frequently put in debate, you will do well to have reasonings ready prepared, and even to get them by heart. It is on these first or most universal theses that respondents become often reluctant and disgusted. To be expert in handling primary doctrines and probabilities, and to be well provided with the definitions from which syllogisms must start, is to the dialectician an acquisition of the highest moment; like familiarity with the Axioms to a geometer, and ready application of the multiplication table to an arithmetical calculator.459When you have these generalities and major propositions firmly established in your mind, you will recall, in a definite order and arrangement, the particular matters fallingunder each of them, and will throw them more easily into syllogisms. They will assist you in doing this, just as the mere distribution of places in a scheme for topical memory makes you recollect what is associated with each. You should lodge in your memory, however, universal major premisses rather than complete and ready-made reasonings; for the great difficulty is about theprincipia.460