Aristotle

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 an eristic or contentious syllogism; (2) If the conclusion be good but not relevant to the thesis, which is most likely to happen where you employ Reductio ad Impossible; (3) If your conclusion though valid and even relevant, is not founded on the premisses and principia appropriate 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

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.438 On 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

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.440 For, if it be derived from premisses false yet probable, it has logical or dialectical value; while, if derived from premisses true yet improbable, it has none.441 If 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.

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

Five distinct modes may be enumerated of committing the fault called Petitio 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

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

3. If you are seeking to prove an universal conclusion, you may 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

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

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

There are also five distinct modes of Petitio Contrariorum:—

1. You may ask the respondent, in plain terms, to grant first the affirmative, next, the negative, of a given proposition.448

2. You may ask him to grant, first, that a given subject is, e.g., good, next, that the same subject is bad.449

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

4. You may ask the contrary of that which follows necessarily from the premisses admitted.451

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

There is this difference between Petitio Principii, and Petitio 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

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 the Reductio ad Absurdum is one case.454 You ought to test every thesis by first assuming it to be true, then assuming it to be false, and following out the consequences on both sides.455 When 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.456 Put 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

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

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.459 When you have these generalities and major propositions firmly established in your mind, you will recall, in a definite order and arrangement, the particular matters falling under 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 the principia.460

You ought also to accustom yourself to break down one reasoning into many; which will be done most easily when the theme of the reasoning is most universal. Conceal this purpose as well as you can; and in this view begin with those particulars which lie most remote from the subject in hand.461 In recording arguments for your own instruction, you will generalize them as much as possible, though perhaps when spoken they may have been particular; for this is the best way to break down one into several. In conducting your own case as questioner you will avoid the higher generalities as much as you can.462 But you must at the same time take care to keep up some common or general premisses throughout the discourse; for every syllogistic process, even where the conclusion is particular, implies this, and no syllogism is valid without it.463

Exercise in inductive discourse is most suitable for a young beginner; exercise in deductive or syllogistic discourse, for skilful veterans. From those who are accomplished in the former you can learn the art of multiplying particular comparisons; from those who are accomplished in the latter you derive universal premisses; such being the strong points of each. When you go through a dialectical exercise, try to bring away with you for future use either some complete syllogism, or some solution of an apparent refutation, or a major premiss, or a well-sustained exceptional example (ἔνστασιν); note also whether either you or your respondent question correctly or otherwise, and on what reason such correctness or incorrectness turned.464 It is the express purpose of dialectical exercise to acquire power and facility in this procedure, especially as regards universal premisses and special exceptions. Indeed the main characteristic of the dialectician is to be apt at universal premisses, and apt at special exceptions. In the first of these two aptitudes he groups many particulars into one universal, without which he cannot make good his syllogism; in the second of the two he breaks up the one universal into many, distinguishing the separate constituents, and denying some while he affirms others.465

You must take care however not to carry on this exercise with every one, especially with a vulgar-minded man. With some persons the dispute cannot fail to take a discreditable turn. When the respondent tries to make a show of escaping by unworthy manœuvres, the questioner on his part must be unscrupulous also in syllogizing; but this is a disgraceful scene. To keep clear of such abusive discourse, you must be cautious not to discourse with commonplace, unprepared, respondents.466

CHAPTER X.

SOPHISTICI ELENCHI.

The Sophist (according to Aristotle) is one whose professional occupation it is to make money by a delusive show of wisdom without the reality — by contriving to make others believe falsely that he possesses wisdom and knowledge. The abstract substantive noun Sophistic, with the verb to practice as a Sophist (σοφιστεύειν), expresses such profession and purpose.1 This application of the term is derived from Plato, who has in various dialogues (Protagoras, Hippias, Euthydêmus, &c.) introduced Sokrates conversing with different professional Sophists, and who has, in a longer dialogue called Sophistes, attempted an elaborate definition of the intellectual peculiarities of the person so named. It is the actual argumentative procedure of the Sophist that Aristotle proposes to himself as the theme of this little treatise, appended to his general theory of the Syllogism; a treatise which, though forming properly the Ninth and concluding Book of the Topica, is commonly known as a separate appendix thereto, under the title of Sophistici Elenchi, or Sophistical Refutations.

The Sophistical Elenchus or Refutation, being a delusive semblance of refutation which imposes on ordinary men and induces them to accept it as real, cannot be properly understood without the theory of Elenchus in general; nor can this last be understood without the entire theory of the Syllogism, since the Elenchus is only one variety of Syllogism.2 The Elenchus is a syllogism with a conclusion contradictory to or refutative of some enunciated thesis or proposition. Accordingly we must first understand the conditions of a good and valid Syllogism, before we study those of a valid Elenchus; these last, again, must be understood, before we enter on the distinctive attributes of the Pseudo-elenchus — the sophistical, invalid, or sham, refutation. In other words, an enumeration and classification of Fallacies forms the closing section of a treatise on Logic — according to the philosophical arrangement originating with Aristotle, and copied by most logicians after him.

Aristotle begins by distinguishing reality and mere deceptive appearance; and by stating that this distinction is found to prevail not less in syllogisms than in other matters. Next he designates a notorious class of persons, called Sophists, who made it their profession to study and practise the deceptive appearance of syllogizing; and he then proceeds to distinguish four species of debate:— (1) Didactic; (2) Dialectic; (3) Peirastic; (4) Eristic or Sophistic.3 In this quadruple arrangement, however, he is not consistent with his own definitions, when he ranks the four as distinct and co-ordinate species. The marked and special antithesis is between Didactic and Dialectic. Both Peirastic and Eristic fall as varieties or sub-species under the species Dialectic; and there is under the species Didactic a variety called Pseudo-graphic or Pseudo-didactic, which stands to Didactic in the same relation in which Eristic stands to Dialectic.4

Didactic discourse is not applicable to all matters indiscriminately, but only to certain special sciences; each of which has its own separate, undemonstrable principia, from which its conclusions, so far as true and valid, must be deduced. It supposes a teacher acquainted with these principia and deductions, talking with some one who being ignorant of them wishes to learn. The teacher puts questions, to which the learner makes the best answers that he can; and, if the answers are wrong, corrects them and proceeds to draw, according to syllogistic canons, conclusions from premisses which he himself knows to be the truth. These premisses the learner must believe upon the teacher’s authority. Properly speaking, indeed, the didactic process is not interrogative (in the same sense that Dialectic is): the teacher does not accept the learner’s answer and reason from it, if he thinks it wrong.5

Dialectic, on the contrary, is applicable to all matters universally and indiscriminately, including even the undemonstrable principia which the teacher assumes as the highest premisses of his didactic syllogisms. It supposes, in place of teacher and learner, an interrogator (or opponent) and a respondent. The respondent declares a problem or thesis, which he undertakes to defend; while the other puts questions to him respecting it, with the purpose of compelling him either to contradict the thesis, or to contradict himself on some other point. The interrogator is allowed only to ask questions, and to deduce legitimate conclusions from the premisses granted by the respondent in answer: he is not permitted to introduce any other premisses. The premisses upon which the debate turns are understood all to be probable — opinions accredited either among an ordinary multitude or among a few wise men, but to have no higher authority. Accordingly there is often a conflict of arguments pro and con, much diversified. The process is essentially controversial; and, if the questioner does not succeed in exposing a contradiction, the respondent is victorious, and remains in possession of the field.

Such is the capital antithesis, much dwelt upon by Aristotle, between Didactic and Dialectic. But that which he calls Peirastic, and that which he calls Eristic, are not species co-ordinate with and distinguished from Dialectic: they are peculiar aspects, subordinate varieties or modes, of Dialectic itself. Aristotle himself, indeed, admits Peirastic to be a mode or variety of Dialectic;6 and the like is equally true respecting what he terms Eristic or Sophistic.

These subordinate distinctions turn upon the manner, the limitations, and the purpose, for and under which the dialectical process is conducted. Dialectic is essentially gymnastic and peirastic:7 it may be looked at either as gymnastic, in reference to the two debaters, or as peirastic, in reference to the arguments and doctrines brought forward; intellectual exercise and stimulation of the two speakers and the auditors around being effected by testing and confronting various probable doctrines. It is the common purpose (κοινὸν ἔργον)8 of the two champions, to improve and enlarge this exercise for the instruction of all, by following out a variety of logical consequences and logical repugnancies, bearing more or less directly on the thesis which the respondent chooses and undertakes to defend against a testing cross-examination. Certain rules and limitations are prescribed both for questioner and respondent; but, subject to these rules, each of them is bound to exert all his acuteness for the purpose of gaining victory; and, though one only can gain it, the debate may be well and creditably conducted on both sides. If the rules are not observed, if the assailing champion, bent upon victory at all cost, has recourse to dishonest interrogative tricks, or the defensive champion to perverse and obstructive negations, beyond the prescribed boundary, in that case the debate is called by Aristotle eristic or contentious, from the undue predominance of the controversial spirit and purpose; also sophistic, from the fact that there existed (as he asserts) a class or profession of persons called Sophists, who regularly studied and practised these culpable manœuvres, first with a view to reputation, and ultimately with a view to pecuniary profit, being pretenders to knowledge and wisdom without any reality to justify them.9