CHAPTER III.* (continued 1)
Project Gutenberg EPUB3 edition
Grote, George
Whoever undertakes, bonâ fide, to frame a complete and defensible logical theory, will desire to have before him a copious collection of such difficulties, and will consider those who propound them as useful auxiliaries.45 If he finds no one to propound them, he will have to imagine them for himself. “The philosophy of reasoning” (observes Mr. John Stuart Mill) “must comprise the philosophy of bad as well as of good reasoning.”46 The one cannot be complete without the other. To enumerate the different varieties of apparent evidence which is not real evidence (called Fallacies), and of apparent contradictions which are not real contradictions — referred as far as may be to classes, each illustrated by a suitable type — is among the duties of a logician. He will find this duty much facilitated, if there happen to exist around him an active habit of dialectic debate: ingenious men who really study the modes of puzzling and confuting a well-armed adversary, as well as of defending themselves against the like. Such a habit did exist at Athens: and unless it had existed, the Aristotelian theories on logic would probably never have been framed. Contemporary and antecedent dialecticians, the Megarici among them, supplied the stock of particular examples enumerated and criticised by Aristotle in the Topica:47 which treatise (especially the last book, De Sophisticis Elenchis) is intended both to explain the theory, and to give suggestions on the practice, of logical controversy.
A man who takes lessons in fencing must learn not only how to thrust and parry, but also how to impose on his opponent by feints, and to meet the feints employed against himself: a general who learns the art of war must know how to take advantage of the enemy by effective cheating and treachery (to use the language of Xenophon), and how to avoid being cheated himself. The Aristotelian Topica, in like manner, teach the arts both of dialectic attack and of dialectic defence.48
Sophisms propounded by Eubulides. 1. Mentiens. 2. The Veiled Man. 3. Sorites. 4. Cornutus.
The Sophisms ascribed to Eubulidês, looked at from the point of view of logical theory, deserve that attention which they seem to have received. The logician lays down as a rule that no affirmative proposition can be at the same time true and false. Now the first sophism (called Mentiens) exhibits the case of a proposition which is, or appears to be, at the same time true and false.49 It is for the logician to explain how this proposition can be brought under his rule — or else to admit it as an exception. Again, the second sophism in the list (the Veiled or Hidden Man) is so contrived as to involve the respondent in a contradiction: he is made to say both that he knows his father, and that he does not know his father. Both the one answer and the other follow naturally from the questions and circumstances supposed. The contradiction points to the loose and equivocal way in which the word to know is used in common speech. Such equivocal meaning of words is not only one of the frequent sources of error and fallacy in reasoning, but also one of the least heeded by persons untrained in dialectics; who are apt to presume that the same word bears always the same meaning. To guard against this cause of error, and to determine (or impel others to determine) the accurate meaning or various distinct meanings of each word, is among the duties of the logician: and I will add that the verb to know stands high in the list of words requiring such determination — as the Platonic Theætêtus50 alone would be sufficient to teach us.
Farthermore, when we examine what is called the Soritês of Eubulides, we perceive that it brings to view an inherent indeterminateness of various terms: indeterminateness which cannot be avoided, but which must be pointed out in order that it may not mislead. You cannot say how many grains are much — or how many grains make a heap. When this want of precision, pervading many words in the language, was first brought to notice in a suitable special case, it would naturally appear a striking novelty. Lastly, the sophism called Κερατίνης or Cornutus, is one of great plausibility, which would probably impose upon most persons, if the question were asked for the first time without any forewarning. It serves to administer a lesson, nowise unprofitable or superfluous, that before you answer a question, you should fully weigh its import and its collateral bearings.
Causes of error constant — the Megarics were sentinals against them.
The causes of error and fallacy are inherent in the complication of nature, the imperfection of language, the small range of facts which we know, the indefinite varieties of comparison possible among those facts, and the diverse or opposite predispositions, intellectual as well as emotional, of individual minds. They are not fabricated by those who first draw attention to them.51 The Megarics, far from being themselves deceivers, served as sentinels against deceit. They planted conspicuous beacons upon some of the sunken rocks whereon unwary reasoners were likely to be wrecked. When the general type of a fallacy is illustrated by a particular case in which the conclusion is manifestly untrue, the like fallacy is rendered less operative for the future.
Controversy of the Megarics with Aristotle about Power. Arguments of Aristotle.
Of the positive doctrines of the Megarics we know little: but there is one upon which Aristotle enters into controversy with them, and upon which (as far as can be made out) I think they were in the right. In the question about Power, they held that the power to do a thing did not exist, except when the thing was actually done: that an architect, for example, had no power to build a house, except when he actually did build one. Aristotle controverts this opinion at some length; contending that there exists a sort of power or cause which is in itself irregular and indeterminate, sometimes turning to the affirmative, sometimes to the negative, to do or not to do;52 that the architect has the power to build constantly, though he exerts it only on occasion: and that many absurdities would follow if we did not admit, That a given power or energy — and the exercise of that power — are things distinct and separable.53
These arguments not valid against the Megarici.
Now these arguments of Aristotle are by no means valid against the Megarics, whose doctrine, though apparently paradoxical, will appear when explained to be no paradox at all, but perfectly true. When we say that the architect has power to build, we do not mean that he has power to do so under all supposable circumstances, but only under certain conditions: we wish to distinguish him from non-professional men, who under those same conditions have no power to build. The architect must be awake and sober: he must have the will or disposition to build:54 he must be provided with tools and materials, and be secure against destroying enemies. These and other conditions being generally understood, it is unnecessary to enunciate them in common speech. But when we engage in dialectic analysis, the accurate discussion (ἀκριβολογία) indispensable to philosophy requires us to bring under distinct notice, that which the elliptical character of common speech implies without enunciating. Unless these favourable conditions be supposed, the architect is no more able to build than an ordinary non-professional man. Now the Megarics did not deny the distinctive character of the architect, as compared with the non-architect: but they defined more accurately in what it consisted, by restoring the omitted conditions. They went a step farther: they pointed out that whenever the architect finds himself in concert with these accompanying conditions (his own volition being one of the conditions) he goes to work — and the building is produced.
As the house is not built, unless he wills to build, and has tools and materials, &c. — so conversely, whenever he has the will to build and has tools and materials, &c., the house is actually built. The effect is not produced, except when the full assemblage of antecedent conditions come together: but as soon as they do come together, the effect is assuredly produced. The accomplishments of the architect, though an essential item, are yet only one item among several, of the conditions necessary to building the house. He has no power to build, except when those other conditions are assumed along with him: in other words, he has no such power except when he actually does build.
His arguments cited and criticised.
Aristotle urges against the Megarics various arguments, as follows:—1. Their doctrine implies that the architect is not an architect, and does not possess his professional skill,55 except at the moment when he is actually building. — But the Megarics would have denied that their doctrine did imply this. The architect possesses his art at all times: but his art does not constitute a power of building except under certain accompanying conditions.
2. The Megaric doctrine is the same as that of Protagoras, implying that there exists no perceivable Object, and no Subject capable of perceiving, except at the moment when perception actually takes place.56 On this we may observe, that the Megarics coincide with Protagoras thus far, that they bring into open daylight the relative and conditional, which the received phraseology tends to hide. But neither they nor he affirm what is here put upon them. When we speak of a perceivable Object, we mean that which may and will be perceived, if there be a proper Subject to perceive it: when we affirm a Subject capable of perception, we mean, one which will perceive, under those circumstances which we call the presence of an Object suitably placed. The Subject and Object are correlates: but it is convenient to have a language in which one of them alone is introduced unconditionally, while the conditional sign is applied to the correlate: though the matter affirmed involves a condition common to both.
3. According to the Megaric doctrine (Aristotle argues) every man when not actually seeing, is blind; every man when not actually speaking, is dumb. — Here the Megarics would have said that this is a misinterpretation of the terms dumb and blind; which denote a person who cannot speak or see, even though he wishes it. One who is now silent, though not dumb, may speak if he wills it: but his own volition is an essential condition.57
Source notes
45 Marbach (Gesch. der Philos. s. 91), though he treats the Megarics as jesters (which I do not think they were), yet adds very justly: “Nevertheless these puzzles (propounded by the Megarics) have their serious and scientific side. We are forced to inquire, how it happens that the contradictions shown up in them are not merely possible but even necessary.”
Both Tiedemann and Winckelmann also remark that the debaters called Eristics contributed greatly to the formation of the theory and precepts of Logic, afterwards laid out by Aristotle. Winckelmann, Prolegg. ad Platon. Euthydem. pp. xxiv.-xxxi. Even Stallbaum, though full of harshness towards those Sophists whom he describes as belonging to the school of Protagoras, treats the Megaric philosophers with much greater respect. Prolegom. ad Platon. Euthydem. p. 9.
46 System of Logic, Book v. 1, 1.
47 Prantl (Gesch. der Logik, vol. i. pp. 43-50) ascribes to the Megarics all or nearly all the sophisms which Aristotle notices in the Treatise De Sophisticis Elenchis. This is more than can be proved, and more than I think probable. Several of them are taken from the Platonic Euthydêmus.
48 See the remarkable passages in the discourses of Sokrates (Memorab. iii. 1, 6; iv. 2, 15), and in that of Kambyses to Cyrus, which repeats the same opinion — Cyropæd. i. 6, 27 — respecting the amount of deceit, treachery, the thievish and rapacious qualities required for conducting war against an enemy — (τὰ πρὸς τοὺς πολεμίους νόμιμα, i. 6, 34).
Aristotle treats of Dialectic, as he does of Rhetoric, as an art having its theory, and precepts founded upon that theory. I shall have occasion to observe in a future chapter (xxi.), that logical Fallacies are not generated or invented by persons called Sophists, but are inherent liabilities to error in the human intellect; and that the habit of debate affords the only means of bringing them into clear daylight, and guarding against being deceived by them. Aristotle gives precepts both how to thrust, and how to parry with the best effect: if he had taught only how to parry, he would have left out one-half of the art.
One of the most learned and candid of the Aristotelian commentators — M. Barthélemy St. Hilaire — observes as follows (Logique d’Aristote, p. 435, Paris, 1838) respecting De Sophist. Elenchis:—
“Aristote va donc s’occuper de la marche qu’il faut donner aux discussions sophistiques: et ici il serait difficile quelquefois de décider, à la manière dont les choses sont présentées par lui, si ce sont des conseils qu’il donne aux Sophistes, ou à ceux qui veulent éviter leurs ruses. Tout ce qui précède, prouve, au reste, que c’est en ce dernier sens qu’il faut entendre la pensée du philosophe. Ceci est d’ailleurs la seconde portion du traîté.”
It appears to me that Aristotle intended to teach or to suggest both the two things which are here placed in Antithesis — though I do not agree with M. St. Hilaire’s way of putting the alternative — as if there were one class of persons, professional Sophists, who fenced with poisoned weapons, while every one except them refrained from such weapons. Aristotle intends to teach the art of Dialectic as a whole; he neither intends nor wishes that any learners shall make a bad use of his teaching; but if they do use it badly, the fault does not lie with him. See the observations in the beginning of the Rhetorica, i. p. 1355, a. 26, and the observations put by Plato into the mouth of Gorgias (Gorg. p. 456 E).
Even in the Analytica Priora (ii. 19, a. 34) (independent of the Topica) Aristotle says:—χρὴ δ’ ὅπερ φυλάττεσθαι παραγγέλλομεν ἀποκρινομένους, αὐτοὺς ἐπιχειροῦντας πειρᾶσθται λανθάνειν. Investigations of the double or triple senses of words (he says) are useful — καὶ πρὸς τὸ μὴ παραλογισθῆναι, καὶ πρὸς τὸ παραλογίσασθαι, Topica, i. 18, p. 108, a. 26. See also other passages of the Topica where artifices are indicated for the purpose of concealing your own plan of proceeding and inducing your opponent to make answer in the sense which you wish, Topica, i. 2, p. 101, a. 25; vi. 10, p. 148, a. 37; viii. 1, p. 151, b. 23; viii. 1, p. 153, a. 6; viii. 2, p. 154, a. 5; viii. 11, p. 161, a. 24 seq. You must be provided with the means of meeting every sort and variety of objection — πρὸς γὰρ τὸν πάντως ἐνιστάμενον πάντως ἀντιτακτέον ἐστίν. Topic. v. 4, p. 134, a. 4.
I shall again have to touch on the Topica, in this point of view, as founded upon and illustrating the Megaric logical puzzles (ch. viii. of the present volume).
49 Theophrastus wrote a treatise in three books on the solution of the puzzle called Ὁ ψευδόμενος (see the list of his lost works in Diogenes L. v. 49). We find also other treatises entitled Μεγαρικὸς ά (which Diogenes cites, vi. 22), — Ἀγωνιστικὸν τῆς περὶ τοὺς ἐριστικοὺς λόγους θεωρίας — Σοφισμάτων ά, β — besides several more titles relating to dialectics, and bearing upon the solution of syllogistic problems. Chrysippus also, in the ensuing century, wrote a treatise in three books, Περὶ τῆς τοῦ ψευδομένον λύσεως (Diog. vii. 107). Such facts show the importance of these problems in their bearing upon logical theory, as conceived by the ancient world. Epikurus also wrote against the Μεγαρικοί (Diog. x. 27).
The discussion of sophisms, or logical difficulties (λύσεις ἀπορίων), was a favourite occupation at the banquets of philosophers at Athens, on or about 100 B.C. Ἀντίπατρος δ’ ὁ φιλόσοφος, συμπόσιόν ποτε συνάγων, συνέταξε τοῖς ἐρχομένοις ὡς περὶ σοφισμάτων ἑροῦσιν (Athenæus, v. 186 C). Plutarch, Non posse suaviter vivi secundum Epicurum, p. 1096 C; De Sanitate Præcepta, c. 20, p. 133 B.
50 Various portions of the Theætêtus illustrate this Megaric sophism (pp. 165-188). The situation assumed in the question of Eubulidês — having before your eyes a person veiled — might form a suitable addition to the various contingencies specified in Theætêt. pp. 192-193.
The manner in which the Platonic Sokrates proves (Theæt. 165) that you at the same time see, and do not see, an object before you, is quite as sophistical as the way in which Eubulidês proves that you both know, and do not know, your father.
51 Cicero, in his Academ. Prior, ii. 92-94, has very just remarks on the obscurities and difficulties in the reasoning process, which the Megarics and others brought to view — and were blamed for so doing, as unfair and captious reasoners — as if they had themselves created the difficulties — “(Dialectica) primo progressu festivé tradit elementa loquendi et ambiguorum intelligentiam concludendique rationem; tum paucis additis venit ad soritas, lubricum sané et periculosum locum, quod tu modo dicebas esse vitiosum interrogandi genus. Quid ergo? istius vitii num nostra culpa est? Rerum natura nullam nobis dedit cognitionem finium, ut ullâ in re statuere possimus quatenus. Nec hoc in acervo tritici solum, unde nomen est, sed nullâ omnino in re minutatim interroganti — dives, pauper — clarus, obscurus, sit — multa, pauca, magna, parva, longa, brevia, lata, angusta, quanto aut addito aut dempto certum respondeamus, non habemus. At vitiosi sunt soritæ. Frangite igitur eos, si potestis, ne molesti sint.… Sic me (inquit) sustineo, neque diutius captiosé interroganti respondes. Si habes quod liqueat neque respondes, superbis: si non habes, ne tu quidem percipis.”
The principle of the Sorites (ἡ σωριτικὴ ἀπορία — Sextus adv. Gramm. s. 68), though differently applied, is involved in the argument of Zeno the Eleate, addressed to Protagoras — see Simplikius ad Aristot. Physic. 250, p. 423, b. 42. Sch. Brand. Compare chap. ii. of this volume.
52 Aristot. De Interpret. p. 19, a. 6-20. ὅλως ἔστιν ἐν τοῖς μὴ ἀεὶ ἐνεργοῦσι τὸ δυνατὸν εἶναι καὶ μὴ ὁμοίως· ἐν οἷς ἀμφω ἐνδέχεται, καὶ τὸ εἶναι καὶ τὸ μὴ εἶναι, ὥστε καὶ τὸ γενέσθαι καὶ τὸ μὴ γενέσθαι.
53 Aristot. Metaph. Θ. 3, p. 1046, b. 29. Εἰσὶ δέ τινες, οἴ φασιν, οἷον οἱ Μεγαρικοί, ὅταν ἐνεργῇ, μόνον δύνασθαι, ὅταν δὲ μὴ ἐνεργῇ, μὴ δύνασθαι — οἷον τὸν μὴ οἰκοδομοῦντα οὐ δύνασθαι οἰκοδομεῖν, ἀλλὰ τὸν οἰκοδομοῦντα ὅταν οἰκοδομῇ· ὁμοίως δὲ καὶ ἐπὶ τῶν ἄλλων.
Deycks (De Megaricorum Doctrinâ, pp. 70-71) considers this opinion of the Megarics to be derived from their general Eleatic theory of the Ens Unum et Immotum. But I see no logical connection between the two.
54 About this condition implied in the predicate δυνατός, see Plato, Hippias Minor, p. 366 D.
55 Aristot. Metaph. Θ. 3, 1047, a. 3. ὅταν παύσηται (οἰκοδομῶν) οὐχ ἕξει τὴν τέχνην.
56 Aristot. Metaph. Θ. 3, 1047, a. 8-13.
57 The question between Aristotle and the Megarics has not passed out of debate with modern philosophers.