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Eukleides of Megara—he blended Parmenides with Sokrates.

Eukleides was a Parmenidean, who blended the ethical point of view of Sokrates with the ontology of Parmenides, and followed out that negative Dialectic which was common to Sokrates with Zeno. Parmenides (I have with already said)19 and Zeno after him, recognised no absolute reality except Ens Unum, continuous, indivisible: they denied all real plurality: they said that the plural was Non-Ens or Nothing, i.e. nothing real or absolute, but only apparent, perpetually transient and changing, relative, different as appreciated by one man and by another. Now Sokrates laid it down that wisdom or knowledge of Good, was the sum total of ethical perfection, including within it all the different virtues: he spoke also about the divine wisdom inherent in, or pervading the entire Kosmos or universe.20 Eukleides blended together the Ens of Parmenides with the Good of Sokrates, saying that the two names designated one and the same thing: sometimes called Good, Wisdom, Intelligence, God, &c., and by other names also, but always one and the same object named and meant. He farther maintained that the opposite of Ens, and the opposite of Bonum (Non-Ens, Non-Bonum, or Malum) were things non-existent, unmeaning names, Nothing,21 &c.: i.e. that they were nothing really, absolutely, permanently, but ever varying and dependent upon our ever varying conceptions. The One—the All—the Good—was absolute, immoveable, invariable, indivisible. But the opposite thereof was a non-entity or nothing: there was no one constant meaning corresponding to Non-Ens—but a variable meaning, different with every man who used it.

Doctrine of Eukleides about Bonum.

It was in this manner that Eukleides solved the problem which Sokrates had brought into vogue—What is the Bonum—or (as afterwards phrased) the Summum Bonum? Eukleides pronounced the Bonum to be coincident with the Ens Unum of Parmenides. The Parmenidean thesis, originally belonging to Transcendental Physics or Ontology, became thus implicated with Transcendental Ethics.22

The doctrine compared to that of Plato—changes in Plato.

Plato departs from Sokrates on the same point. He agrees with Eukleides in recognising a Transcendental Bonum. But it appears that his doctrines on this head underwent some change. He held for some time what is called the doctrine of Ideas: transcendental Forms, Entia, Essences: he considered the Transcendental to be essentially multiple, or to be an aggregate—whereas Eukleides had regarded it as essentially One. This is the doctrine which we find in some of the Platonic dialogues. In the Republic, the Idea of Good appears as one of these, though it is declared to be the foremost in rank and the most ascendant in efficacy.23 But in the later part of his life, and in his lectures (as we learn from Aristotle), Plato came to adopt a different view. He resolved the Ideas into numbers. He regarded them as made up by the combination of two distinct factors:—1. The One—the Essentially One. 2. The Essentially Plural: The Indeterminate Dyad: the Great and Little. — Of these two elements he considered the Ideas to be compounded. And he identified the Idea of Good with the essentially One—τὸ ἀγαθὸν with τὸ ἕν: the principle of Good with the principle of Unity: also the principle of Evil with the Indeterminate. But though Unity and Good were thus identical, he considered Unity as logically antecedent, or the subject—Good as logically consequent, or the predicate.24

Last doctrine of Plato nearly the same as that of Eukleides.

This last doctrine of Plato in his later years (which does not appear in the dialogues, but seems, as far as we can make out, to have been delivered substantially in his oral lectures, and is ascribed to him by Aristotle) was nearly coincident with that of Eukleides. Both held the identity of τὸ ἕν with τὸ ἀγαθόν. This one doctrine is all that we know about Eukleides: what consequences he derived from it, or whether any, we do not know. But Plato combined, with this transcendental Unum = Bonum, a transcendental indeterminate plurality: from which combination he considered his Ideas or Ideal Numbers to be derivatives.

Megaric succession of philosophers. Eleian or Eritrean succession.

Eukleides is said to have composed six dialogues, the titles of which alone remain. The scanty information which we possess respecting him relates altogether to his negative logical procedure. Whether he deduced any consequences from his positive doctrine of the Transcendental Ens, Unum, Bonum, we do not know: but he, as Zeno had been before him,25 was acute in exposing contradictions and difficulties in the positive doctrines of opponents. He was a citizen of Megara, where he is said to have harboured Plato and the other companions of Sokrates, when they retired for a time from Athens after the death of Sokrates. Living there as a teacher or debater on philosophy, he founded a school or succession of philosophers who were denominated Megarici. The title is as old as Aristotle, who both names them and criticises their doctrines.26 None of their compositions are preserved. The earliest who becomes known to us is Eubulides, the contemporary and opponent of Aristotle; next Ichthyas, Apollonius, Diodôrus Kronus, Stilpon, Alexinus, between 340–260 B.C.

With the Megaric philosophers there soon become confounded another succession, called Eleian or Eretrian, who trace their origin to another Sokratic man—Phædon. The chief Eretrians made known to us are Pleistanus, Menedêmus, Asklepiades. The second of the three acquired some reputation.

Doctrines of Antisthenes and Aristippus—Ethical, not transcendental.

The Megarics and Eretrians, as far as we know them, turned their speculative activity altogether in the logical or intellectual direction, paying little attention to the ethical and emotional field. Both Antisthenes and Aristippus, on the contrary, pursued the ethical path. To the Sokratic question, What is the Bonum? Eukleides had answered by a transcendental definition: Antisthenes and Aristippus each gave to it an ethical answer, having reference to human wants and emotions, and to the different views which they respectively took thereof. Antisthenes declared it to consist in virtue, by which he meant an independent and self-sufficing character, confining all wants within the narrowest limits: Aristippus placed it in the moderate and easy pleasures, in avoiding ambitious struggles, and in making the best of every different situation, yet always under the guidance of a wise calculation and self-command. Both of them kept clear of the transcendental: they neither accepted it as Unum et Omne (the view of Eukleides), nor as Plura (the Eternal Ideas or Forms, the Platonic view). Their speculations had reference altogether to human life and feelings, though the one took a measure of this wide subject very different from the other: and in thus confining the range of their speculations, they followed Sokrates more closely than either Eukleides or Plato followed him. They not only abstained from transcendental speculation, but put themselves in declared opposition to it. And since the intellectual or logical philosophy, as treated by Plato, became intimately blended with transcendental hypothesis—Antisthenes and Aristippus are both found on the negative side against its pretensions. Aristippus declared the mathematical sciences to be useless, as conducing in no way to happiness, and taking no account of what was better or what was worse.27 He declared that we could know nothing except in so far as we were affected by it, and as it was or might be in correlation with ourselves: that as to causes not relative to ourselves, or to our own capacities and affections, we could know nothing about them.28

Preponderance of the negative vein in the Platonic age.

Such were the leading writers and talkers contemporary with Plato, in the dialectical age immediately following on the death of Sokrates. The negative vein greatly preponderates in them, as it does on the whole even in Plato—and as it was pretty sure to do, so long as the form of dialogue was employed. Affirmative exposition and proof is indeed found in some of the later Platonic works, carried on by colloquy between two speakers. But the colloquial form manifests itself evidently as unsuitable for the purpose: and we must remember that Plato was a lecturer as well as a writer, so that his doctrines made their way, at least in part, through continuous exposition. But it is Aristotle with whom the form of affirmative continuous exposition first becomes predominant, in matters of philosophy. Though he composed dialogues (which are now lost), and though he appreciates dialectic as a valuable exercise, yet he considers it only as a discursive preparation; antecedent, though essential, to the more close and concentrated demonstrations of philosophy.

Harsh manner in which historians of philosophy censure the negative vein.

Most historians deal hardly with this negative vein. They depreciate the Sophists, the Megarics and Eretrians, the Academics and Sceptics of the subsequent ages—under the title of Eristics, or lovers of contention for itself—as captious and perverse enemies of truth.

Negative method in philosophy essential to the controul of the affirmative.

I have already said that my view of the importance and value of the negative vein of philosophy is altogether different. It appears to me quite as essential as the affirmative. It is required as an antecedent, a test, and a corrective. Aristotle deserves all honour for his attempts to construct and defend various affirmative theories: but the value of these theories depends upon their being defensible against all objectors. Affirmative philosophy, as a body not only of truth but of reasoned truth, holds the champion’s belt, subject to the challenge not only of competing affirmants, but of all deniers and doubters. And this is the more indispensable, because of the vast problems which these affirmative philosophers undertake to solve: problems especially vast during the age of Plato and Aristotle. The question has to be determined, not only which of two proposed solutions is the best, but whether either of them is tenable, and even whether any solution at all is attainable by the human faculties: whether there exist positive evidence adequate to sustain any conclusion, accompanied with adequate replies to the objections against it. The burthen of proof lies upon the affirmant: and the proof produced must be open to the scrutiny of every dissentient.

Sokrates—the most persevering and acute Eristic of his age.

Among these dissentients or negative dialecticians, Sokrates himself, during his life, stood prominent. In his footsteps followed Eukleides and the Megarics: who, though they acquired the unenviable surname of Eristics or Controversialists, cannot possibly have surpassed Sokrates, and probably did not equal him, in the refutative Elenchus. Of no one among the Megarics, probably, did critics ever affirm, what the admiring Xenophon says about Sokrates—“that he dealt with every one in colloquial debate just as he chose,” i.e., that he baffled and puzzled his opponents whenever he chose. No one of these Megarics probably ever enunciated so sweeping a negative programme, or declared so emphatically his own inability to communicate positive instruction, as Sokrates in the Platonic Apology. A person more thoroughly Eristic than Sokrates never lived. And we see perfectly, from the Memorabilia of Xenophon (who nevertheless strives to bring out the opposite side of his character), that he was so esteemed among his contemporaries. Plato, as well as Eukleides, took up this vein in the Sokratic character, and worked it with unrivalled power in many of his dialogues. The Platonic Sokrates is compared, and compares himself, to Antæus, who compelled every new-comer, willing or unwilling, to wrestle with him.29

Platonic Parmenides—its extreme negative character.

Of the six dialogues composed by Eukleides, we cannot speak positively, because they are not preserved. But they cannot have been more refutative, and less affirmative, than most of the Platonic dialogues; and we can hardly be wrong in asserting that they were very inferior both in energy and attraction. The Theætêtus and the Parmenides, two of the most negative among the Platonic dialogues, seem to connect themselves, by the personnel of the drama, with the Megaric philosophers: the former dialogue is ushered in by Eukleides, and is, as it were, dedicated to him: the latter dialogue exhibits, as its protagonistes, the veteran Parmenides himself, who forms the one factor of the Megaric philosophy, while Sokrates forms the other. Parmenides (in the Platonic dialogue so called) is made to enforce the negative method in general terms, as a philosophical duty co-ordinate with the affirmative; and to illustrate it by a most elaborate argumentation, directed partly against the Platonic Ideas (here advocated by the youthful Sokrates), partly against his own (the Parmenidean) dogma of Ens Unum. Parmenides adduces unanswerable objections against the dogma of Transcendental Forms or Ideas; yet says at the same time that there can be no philosophy unless you admit it. He reproves the youthful Sokrates for precipitancy in affirming the dogma, and contends that you are not justified in affirming any dogma until you have gone through a bilateral scrutiny of it—that is, first assuming the doctrine to be true, next assuming it to be false, and following out the deductions arising from the one assumption as well as from the other.30 Parmenides then gives a string of successive deductions (at great length, occupying the last half of the dialogue)—four pairs of counter-demonstrations or Antinomies—in which contradictory conclusions appear each to be alike proved. He enunciates the final result as follows:—“Whether Unum exists, or does not exist, Unum itself and Cætera, both exist and do not exist, both appear and do not appear, all things and in all ways—both in relation to themselves and in relation to each other”.31

If this memorable dialogue, with its concluding string of elaborate antinomies, had come down to us under the name of Eukleides, historians would probably have denounced it as a perverse exhibition of ingenuity, worthy of “that litigious person, who first infused into the Megarians the fury of disputation”.32 But since it is of Platonic origin, we must recognise Plato not only as having divided with the Megaric philosophers the impulse of negative speculation which they had inherited from Sokrates, but as having carried that impulse to an extreme point of invention, combination, and dramatic handling, much beyond their powers. Undoubtedly, if we pass from the Parmenidês to other dialogues, we find Plato very different. He has various other intellectual impulses, an abundant flow of ideality and of constructive fancy, in many distinct channels. But negative philosophy is at least one of the indisputable and prominent items of the Platonic aggregate.

The Megarics shared the negative impulse with Sokrates and Plato.

While then we admit that the Megaric succession of philosophers exhibited negative subtlety and vehement love of contentious debate, we must recollect that these qualities were inherited from Sokrates and shared with Plato. The philosophy of Sokrates, who taught nothing and cross-examined every one, was essentially more negative and controversial, both in him and his successors, than any which had preceded it. In an age when dialectic colloquy was considered as appropriate for philosophical subjects, and when long continuous exposition was left to the rhetor—Eukleides established a succession or school33 which was more distinguished for impugning dogmas of others than for defending dogmas of its own. Schleiermacher and others suppose that Plato in his dialogue Euthydêmus intends to expose the sophistical fallacies of the Megaric school:34 and that in the dialogue Sophistês, he refutes the same philosophers (under the vague designation of “the friends of Forms”) in their speculations about Ens and Non-Ens. The first of these two opinions is probably true to some extent, though we cannot tell how far: the second of the two is supported by some able critics—yet it appears to me untenable.35

Of Eukleides himself, though he is characterised as strongly controversial, no distinct points of controversy have been preserved: but his successor Eubulides is celebrated for various sophisms. He was the contemporary and rival of Aristotle: who, without however expressly naming him, probably intends to speak of him when alluding to the Megaric philosophers generally.36 Another of the same school, Alexinus (rather later than Eubulides) is also said to have written against Aristotle.

Eubulides—his logical problems or puzzles—difficulty of solving them—many solutions attempted.

Six sophisms are ascribed to Eubulides. 1. — Ὁ ψευδόμενος—Mentiens. 2. — Ὁ διαλανθάνων, or ἐγκεκαλυμμένος—the person hidden under a veil. 3. — Ἠλέκτρα. 4. — Σωρείτης—Sorites. 5. — Κερατίνης—Cornutus. 6. — Φάλακρος—Calvus. Of these the second is substantially the same with the third; and the fourth the same with the sixth, only inverted.37

These sophisms are ascribed to Eubulides, and belonged probably to the Megaric school both before and after him. But it is plain both from the Euthydêmus of Plato, and from the Topica of Aristotle, that there were many others of similar character; frequently employed in the abundant dialectic colloquies which prevailed at Athens during the fourth and third centuries B.C. Plato and Aristotle handle such questions and their authors contemptuously, under the name of Eristic: but it was more easy to put a bad name upon them, as well as upon the Eleate Zeno, than to elucidate the logical difficulties which they brought to view. Neither Aristotle nor Plato provided a sufficient answer to them: as is proved by the fact, that several subsequent philosophers wrote treatises expressly in reference to them—even philosophers of reputation, like Theophrastus and Chrysippus.38 How these two latter philosophers performed their task, we cannot say. But the fact that they attempted the task, exhibits a commendable anxiety to make their logical theory complete, and to fortify it against objections.

Real character of the Megaric sophisms, not calculated to deceive but to guard against deception.

It is in this point of view—in reference to logical theory—that the Megaric philosophers have not been fairly appreciated. They, or persons reasoning in their manner, formed one essential encouragement and condition to the formation of any tolerable logical theory. They administered, to minds capable and constructive, that painful sense of contradiction, and shock of perplexity, which Sokrates relied upon as the stimulus to mental parturition—and which Plato extols as a lever for raising the student to general conceptions.39 Their sophisms were not intended to impose upon any one, but on the contrary, to guard against imposition.40 Whoever states a fallacy clearly and nakedly, applying it to a particular case in which it conducts to a conclusion known upon other evidence not to be true—contributes to divest it of its misleading effect. The persons most liable to be deceived by the fallacy are those who are not forewarned:—in cases where the premisses are stated not nakedly, but in an artful form of words—and where the conclusion, though false, is not known beforehand to be false by the hearer. To use Mr. John Stuart Mill’s phrase,41 the fallacy is a case of apparent evidence mistaken for real evidence: you expose it to be evidence only apparent and not real, by giving a type of the fallacy, in which the conclusion obtained is obviously false: and the more obviously false it is, the better suited for its tutelary purpose. Aristotle recognises, as indispensable in philosophical enquiry, the preliminary wrestling into which he conducts his reader, by means of a long string of unsolved difficulties or puzzles—(ἀπόριαι). He declares distinctly and forcibly, that whoever attempts to lay out a positive theory, without having before his mind a full list of the difficulties with which he is to grapple, is like one who searches without knowing what he is looking for; without being competent to decide whether what he hits upon as a solution be really a solution or not.42 Now that enumeration of puzzles which Aristotle here postulates (and in part undertakes, in reference to Philosophia Prima) is exactly what the Megarics, and various other dialecticians (called by Plato and Aristotle Sophists) contributed to furnish for the use of those who theorised on Logic.

If the process of theorising be admissible, it must include negative as well as affirmative.

You may dislike philosophy: you may undervalue, or altogether proscribe, the process of theorising. This is the standing-point usual with the bulk of mankind, ancient as well as modern: who generally dislike all accurate reasoning, or analysis and discrimination of familiar abstract words, as mean and tiresome hair-splitting.43 But if you admit the business of theorising to be legitimate, useful, and even honourable, you must reckon on free working of independent, individual, minds as the operative force—and on the necessity of dissentient, conflicting, manifestations of this common force, as essential conditions to any successful result. Upon no other conditions can you obtain any tolerable body of reasoned truth—or even reasoned quasi-truth.

Logical position of the Megaric philosophers erroneously described by historians of philosophy. Necessity of a complete collection of difficulties.

Now the historians of philosophy seldom take this view of philosophy as a whole—as a field to which the free antithesis of affirmative and negative is indispensable. They consider true philosophy as represented by Sokrates, Plato, and Aristotle, one or other of them: while the contemporaries of these eminent men are discredited under the name of Sophists, Eristics, or sham-philosophers, sowing tares among the legitimate crop of wheat—or as devils whom the miraculous virtue of Sokrates and Plato is employed in expelling from the Athenian mind. Even the companions of Sokrates, and the Megarics among them, whom we know only upon the imperfect testimony of opponents, have fallen under this unmerited sentence:44 as if they were destructive agents breaking down an edifice of well-constituted philosophy—no such edifice in fact having ever existed in Greece, though there were several dissenting lecture rooms and conflicting veins of speculation promoted by eminent individuals.

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

4. According to the Megaric doctrine (says Aristotle) when you are now lying down, you have no power to rise: when you are standing up, you have no power to lie down: so that the present condition of affairs must continue for ever unchanged: nothing can come into existence which is not now in being. — Here again, the Megarics would have denied his inference. The man who is now standing up, has power to lie down, if he wills to do so—or he may be thrown down by a superior force: that is, he will lie down, if some new fact of a certain character shall supervene. The Megarics do not deny that he has power, if—so and so: they deny that he has power, without the if—that is, without the farther accompaniments essential to energy.

Potential as distinguished from the Actual—What it is.

On the whole, it seems to me that Aristotle’s refutation of the Megarics is unsuccessful. A given assemblage of conditions is requisite for the production of any act: while there are other circumstances, which, if present at the same time, would defeat its production. We often find it convenient to describe a state of things in which some of the antecedent conditions are present without the rest: in which therefore the act is not produced, yet would be produced, if the remaining circumstances were present, and if the opposing circumstances were absent.58 The state of things thus described is the potential as distinguished from the actual: power, distinguished from act or energy: it represents an incomplete assemblage of the antecedent positive conditions—or perhaps a complete assemblage, but counteracted by some opposing circumstances. As soon as the assemblage becomes complete, and the opposing circumstances removed, the potential passes into the actual. The architect, when he is not building, possesses, not indeed the full or plenary power to build, but an important fraction of that power, which will become plenary when the other fractions supervene, but will then at the same time become operative, so as to produce the actual building.59

Diodôrus Kronus—his doctrine about τὸ δυνατόν.

The doctrine which I have just been canvassing is expressly cited by Aristotle as a Megaric doctrine, and was therefore probably held by his contemporary Eubulidês. From the pains which Aristotle takes (in the ‘De Interpretatione’ and elsewhere) to explain and vindicate his own doctrine about the Potential and the Actual, we may see that it was a theme much debated among the dialecticians of the day. And we read of another Megaric, Diodorus60 Kronus, perhaps contemporary (yet probably a little later than Aristotle), as advancing a position substantially the same as that of Eubulidês. That alone is possible (Diodorus affirmed) which either is happening now, or will happen at some future time. As in speaking about facts of an unrecorded past, we know well that a given fact either occurred or did not occur, yet without knowing which of the two is true—and therefore we affirm only that the fact may have occurred: so also about the future, either the assertion that a given fact will at some time occur, is positively true, or the assertion that it will never occur, is positively true: the assertion that it may or may not occur some time or other, represents only our ignorance, which of the two is true. That which will never at any time occur, is impossible.

Sophism of Diodorus—Ὁ Κυριεύων.

The argument here recited must have been older than Diodorus, since Aristotle states and controverts it: but it seems to have been handled by him in a peculiar dialectic arrangement, which obtained the title of Ὁ Κυριεύων.61 The Stoics (especially Chrysippus), in times somewhat later, impugned the opinion of Diodorus, though seemingly upon grounds not quite the same as Aristotle. This problem was one upon which speculative minds occupied themselves for several centuries. Aristotle and Chrysippus maintained that affirmations respecting the past were necessary (one necessarily true and the other necessarily false)—affirmations respecting the future, contingent (one must be true and the other false, but either might be true). Diodorus held that both varieties of affirmations were equally necessary—Kleanthes the Stoic thought that both were equally contingent.62

It was thus that the Megaric dialecticians, with that fertility of mind which belonged to the Platonic and Aristotelian century, stirred up many real problems and difficulties connected with logical evidence, and supplied matters for discussion which not only occupied the speculative minds of the next four or five centuries, but have continued in debate down to the present day.

Question between Aristotle and Diodôrus depends upon whether universal regularity of sequence be admitted or denied.

The question about the Possible and Impossible, raised between Aristotle and Diodorus, depends upon the larger question, Whether there are universal laws of Nature or not? whether the sequences are, universally and throughout, composed of assemblages of conditions regularly antecedent, and assemblages of events regularly consequent; though from the number and complication of causes, partly co-operating and partly conflicting with each other, we with our limited intelligence are often unable to predict the course of events in each particular situation. Sokrates, Plato, and Aristotle, all maintained that regular sequence of antecedent and consequent was not universal, but partial only:63 that there were some agencies essentially regular, in which observation of the past afforded ground for predicting the future—other agencies (or the same agencies on different occasions) essentially irregular, in which the observation of the past afforded no such ground. Aristotle admitted a graduation of causes from perfect regularity to perfect irregularity:—1. The Celestial Spheres, with their included bodies or divine persons, which revolved and exercised a great and preponderant influence throughout the Kosmos, with perfect uniformity; having no power of contraries, i.e., having no power of doing anything else but what they actually did (having ἐνεργεία without δύναμις). 2. The four Elements, in which the natural agencies were to a great degree necessary and uniform, but also in a certain degree otherwise—either always or for the most part uniform (τὸ ὡς ἐπὶ τὸ πολύ)—tending by inherent appetency towards uniformity, but not always attaining it. 3. Besides these there were two other varieties of Causes accidental, or perfectly irregular—Chance and Spontaneity: powers of contraries, or with equal chance of contrary manifestations—essentially capricious, undeterminable, unpredictable.64 This Chance of Aristotle—with one of two contraries sure to turn up, though you could never tell beforehand which of the two—was a conception analogous to what logicians sometimes call an Indefinite Proposition, or to what some grammarians have reckoned as a special variety of genders called the doubtful gender. There were thus positive causes of regularity, and positive causes of irregularity, the co-operation or conflict of which gave the total manifestations of the actual universe. The principle of irregularity, or the Indeterminate, is sometimes described under the name of Matter,65 as distinguishable from, yet co-operating with, the three determinate Causes—Formal, Efficient, Final. The Potential—the Indeterminate—the May or May not be—is characterised by Aristotle as one of the inherent principles operative in the Kosmos.

Conclusion of Diodôrus—defended by Hobbes—Explanation given by Hobbes.

In what manner Diodorus stated and defended his opinion upon this point, we have no information. We know only that he placed affirmations respecting the future on the same footing as affirmations respecting the past: maintaining that our potential affirmation—May or May not be—respecting some future event, meant no more than it means respecting some past event, viz.: no inherent indeterminateness in the future sequence, but our ignorance of the determining conditions, and our inability to calculate their combined working.66 In regard to scientific method generally, this problem is of the highest importance: for it is only so far as uniformity of sequence prevails, that facts become fit matter for scientific study.67 Consistently with the doctrine of all-pervading uniformity of sequence, the definition of Hobbes gives the only complete account of the Impossible and Possible: i.e. an account such as would appear to an omniscient calculator, where May or May not merge in Will or Will not. According as each person falls short of or approaches this ideal standard—according to his knowledge and mental resource, inductive and deductive—will be his appreciation of what may be or may not be—as of what may have been or may not have been during the past. But such appreciation, being relative to each individual mind, is liable to vary indefinitely, and does not admit of being embodied in one general definition.

Besides the above doctrine respecting Possible and Impossible, there is also ascribed to Diodorus a doctrine respecting Hypothetical Propositions, which, as far as I comprehend it, appears to have been a correct one.68 He is also said to have reasoned against the reality of motion, renewing the arguments of Zeno the Eleate.

Reasonings of Diodôrus—respecting Hypothetical Propositions—respecting Motion. His difficulties about the Now of time.

But if he reproduced the arguments of Zeno, he also employed another, peculiar to himself. He admitted the reality of past motion: but he denied the reality of present motion. You may affirm truly (he said) that a thing has been moved: but you cannot truly affirm that any thing is being moved. Since it was here before, and is there now, you may be sure that it has been moved: but actual present motion you cannot perceive or prove. Affirmation in the perfect tense may be true, when affirmation in the present tense neither is nor ever was true: thus it is true to say—Helen had three husbands (Menelaus, Paris, Deiphobus): but it was never true to say—Helen has three husbands, since they became her husbands in succession.69 Diodorus supported this paradox by some ingenious arguments, and the opinion which he denied seems to have presented itself to him as involving the position of indivisible minima—atoms of body, points of space, instants of time. He admitted such minima of atoms, but not of space or time: and without such admission he could not make intelligible to himself the fact of present or actual motion. He could find no present Now or Minimum of Time; without which neither could any present motion be found. Plato in the Parmenidês70 professes to have found this inexplicable moment of transition, but he describes it in terms not likely to satisfy a dialectical mind: and Aristotle denying that the Now is any portion or constituent part of time, considers it only as a boundary of the past and future.71

Motion is always present, past, and future.

This opinion of Aristotle is in the main consonant with that of Diodorus; who, when he denied the reality of present motion, meant probably only to deny the reality of present motion apart from past and future motion. Herein also we find him agreeing with Hobbes, who denies the same in clearer language.72 Sextus Empiricus declares Diodorus to have been inconsistent in admitting past motion while he denied present motion.73 But this seems not more inconsistent than the doctrine of Aristotle respecting the Now of time. I know, when I compare a child or a young tree with what they respectively were a year ago, that they have grown: but whether they actually are growing, at every moment of the intervening time, is not ascertainable by sense, and is a matter of probable inference only.74 Diodorus could not understand present motion, except in conjunction with past and future motion, as being the common limit of the two: but he could understand past motion, without reference to present or future. He could not state to himself a satisfactory theory respecting the beginning of motion: as we may see by his reasonings distinguishing the motion of a body all at once in its integrity, from the motion of a body considered as proceeding from the separate motion of its constituent atoms—the moving atoms preponderating over the atoms at rest, and determining them to motion,75 until gradually the whole body came to move. The same argument re-appears in another example, when he argues—The wall does not fall while its component stones hold together, for then it is still standing: nor yet when they have come apart, for then it has fallen.76

Stilpon of Megara—His great celebrity.

That Diodorus was a person seriously anxious to solve logical difficulties, as well as to propose them, would be incontestably proved if we could believe the story recounted of him—that he hanged himself because he could not solve a problem proposed by Stilpon in the presence of Ptolemy Soter.77 But this story probably grew out of the fact, that Stilpon succeeded Diodorus at Megara, and eclipsed him in reputation. The celebrity of Stilpon, both at Megara and at Athens (between 320–300 B.C., but his exact date can hardly be settled), was equal, if not superior, to that of any contemporary philosopher. He was visited by listeners from all parts of Greece, and he drew away pupils from the most renowned teachers of the day; from Theophrastus as well as the others.78 He was no less remarkable for fertility of invention than for neatness of expression. Two persons, who came for the purpose of refuting him, are said to have remained with him as admirers and scholars. All Greece seemed as it were looking towards him, and inclining towards the Megaric doctrines.79 He was much esteemed both by Ptolemy Soter and by Demetrius Poliorkêtes, though he refused the presents and invitations of both: and there is reason to believe that his reputation in his own day must have equalled that of either Plato or Aristotle in theirs. He was formidable in disputation; but the nine dialogues which he composed and published are characterised by Diogenes as cold.80

Menedêmus and the Eretriacs.

Contemporary with Stilpon (or perhaps somewhat later) was Menedêmus of Eretria, whose philosophic parentage is traced to Phædon. The name of Phædon has been immortalised, not by his own works, but by the splendid dialogue of which Plato has made him the reciter. He is said (though I doubt the fact) to have been a native of Elis. He was of good parentage, a youthful companion of Sokrates in the last years of his life.81 After the death of Sokrates, Phædon went to Elis, composed some dialogues, and established a succession or sect of philosophers—Pleistanus, Anchipylus, Moschus. Of this sect Menedêmus,82 contemporary and hearer of Stilpon, became the most eminent representative, and from him it was denominated Eretriac instead of Eleian. The Eretriacs, as well as the Megarics, took up the negative arm of philosophy, and were eminent as puzzlers and controversialists.

Open speech and licence of censure assumed by Menedêmus.

But though this was the common character of the two, in a logical point of view, yet in Stilpon, as well as Menedêmus, other elements became blended with the logical. These persons combined, in part at least, the free censorial speech of Antisthenes with the subtlety of Eukleides. What we hear of Menedêmus is chiefly his bitter, stinging sarcasms, and clever repartees. He did not, like the Cynic Diogenes, live in contented poverty, but occupied a prominent place (seemingly under the patronage of Antigonus and Demetrius) in the government of his native city Eretria. Nevertheless he is hardly less celebrated than Diogenes for open speaking of his mind, and carelessness of giving offence to others.83