The Euthydemus, though apt to be regarded by us only as an elaborate jest, has also a very serious purpose. It may fairly claim to be the oldest treatise on logic; for that science originates in the misunderstandings which necessarily accompany the first efforts of speculation. Several of the fallacies which are satirized in it reappear in the Sophistici Elenchi of Aristotle and are retained at the end of our manuals of logic. But if the order of history were followed, they should be placed not at the end but at the beginning of them; for they belong to the age in which the human mind was first making the attempt to distinguish thought from sense, and to separate the universal from the particular or individual. How to put together words or ideas, how to escape ambiguities in the meaning of terms or in the structure of propositions, how to resist the fixed impression of an 'eternal being' or 'perpetual flux,' how to distinguish between words and things – these were problems not easy of solution in the infancy of philosophy. They presented the same kind of difficulty to the half-educated man which spelling or arithmetic do to the mind of a child. It was long before the new world of ideas which had been sought after with such passionate yearning was set in order and made ready for use. To us the fallacies which arise in the pre-Socratic philosophy are trivial and obsolete because we are no longer liable to fall into the errors which are expressed by them. The intellectual world has become better assured to us, and we are less likely to be imposed upon by illusions of words.
The logic of Aristotle is for the most part latent in the dialogues of Plato. The nature of definition is explained not by rules but by examples in the Charmides, Lysis, Laches, Protagoras, Meno, Euthyphro, Theaetetus, Gorgias, Republic; the nature of division is likewise illustrated by examples in the Sophist and Statesman; a scheme of categories is found in the Philebus; the true doctrine of contradiction is taught, and the fallacy of arguing in a circle is exposed in the Republic; the nature of synthesis and analysis is graphically described in the Phaedrus; the nature of words is analysed in the Cratylus; the form of the syllogism is indicated in the genealogical trees of the Sophist and Statesman; a true doctrine of predication and an analysis of the sentence are given in the Sophist; the different meanings of one and being are worked out in the Parmenides. Here we have most of the important elements of logic, not yet systematized or reduced to an art or science, but scattered up and down as they would naturally occur in ordinary discourse. They are of little or no use or significance to us; but because we have grown out of the need of them we should not therefore despise them. They are still interesting and instructive for the light which they shed on the history of the human mind.
There are indeed many old fallacies which linger among us, and new ones are constantly springing up. But they are not of the kind to which ancient logic can be usefully applied. The weapons of common sense, not the analytics of Aristotle, are needed for their overthrow. Nor is the use of the Aristotelian logic any longer natural to us. We no longer put arguments into the form of syllogisms like the schoolmen; the simple use of language has been, happily, restored to us. Neither do we discuss the nature of the proposition, nor extract hidden truths from the copula, nor dispute any longer about nominalism and realism. We do not confuse the form with the matter of knowledge, or invent laws of thought, or imagine that any single science furnishes a principle of reasoning to all the rest. Neither do we require categories or heads of argument to be invented for our use. Those who have no knowledge of logic, like some of our great physical philosophers, seem to be quite as good reasoners as those who have. Most of the ancient puzzles have been settled on the basis of usage and common sense; there is no need to reopen them. No science should raise problems or invent forms of thought which add nothing to knowledge and are of no use in assisting the acquisition of it. This seems to be the natural limit of logic and metaphysics; if they give us a more comprehensive or a more definite view of the different spheres of knowledge they are to be studied; if not, not. The better part of ancient logic appears hardly in our own day to have a separate existence; it is absorbed in two other sciences: (1) rhetoric, if indeed this ancient art be not also fading away into literary criticism; (2) the science of language, under which all questions relating to words and propositions and the combinations of them may properly be included.
To continue dead or imaginary sciences, which make no signs of progress and have no definite sphere, tends to interfere with the prosecution of living ones. The study of them is apt to blind the judgment and to render men incapable of seeing the value of evidence, and even of appreciating the nature of truth. Nor should we allow the living science to become confused with the dead by an ambiguity of language. The term logic has two different meanings, an ancient and a modern one, and we vainly try to bridge the gulf between them. Many perplexities are avoided by keeping them apart. There might certainly be a new science of logic; it would not however be built up out of the fragments of the old, but would be distinct from them – relative to the state of knowledge which exists at the present time, and based chiefly on the methods of Modern Inductive philosophy. Such a science might have two legitimate fields: first, the refutation and explanation of false philosophies still hovering in the air as they appear from the point of view of later experience or are comprehended in the history of the human mind, as in a larger horizon: secondly, it might furnish new forms of thought more adequate to the expression of all the diversities and oppositions of knowledge which have grown up in these latter days; it might also suggest new methods of enquiry derived from the comparison of the sciences. Few will deny that the introduction of the words 'subject' and 'object' and the Hegelian reconciliation of opposites have been 'most gracious aids' to psychology, or that the methods of Bacon and Mill have shed a light far and wide on the realms of knowledge. These two great studies, the one destructive and corrective of error, the other conservative and constructive of truth, might be a first and second part of logic. Ancient logic would be the propaedeutic or gate of approach to logical science, – nothing more. But to pursue such speculations further, though not irrelevant, might lead us too far away from the argument of the dialogue.
The Euthydemus is, of all the Dialogues of Plato, that in which he approaches most nearly to the comic poet. The mirth is broader, the irony more sustained, the contrast between Socrates and the two Sophists, although veiled, penetrates deeper than in any other of his writings. Even Thrasymachus, in the Republic, is at last pacified, and becomes a friendly and interested auditor of the great discourse. But in the Euthydemus the mask is never dropped; the accustomed irony of Socrates continues to the end…
Socrates narrates to Crito a remarkable scene in which he has himself taken part, and in which the two brothers, Dionysodorus and Euthydemus, are the chief performers. They are natives of Chios, who had settled at Thurii, but were driven out, and in former days had been known at Athens as professors of rhetoric and of the art of fighting in armour. To this they have now added a new accomplishment – the art of Eristic, or fighting with words, which they are likewise willing to teach 'for a consideration.' But they can also teach virtue in a very short time and in the very best manner. Socrates, who is always on the look-out for teachers of virtue, is interested in the youth Cleinias, the grandson of the great Alcibiades, and is desirous that he should have the benefit of their instructions. He is ready to fall down and worship them; although the greatness of their professions does arouse in his mind a temporary incredulity.
A circle gathers round them, in the midst of which are Socrates, the two brothers, the youth Cleinias, who is watched by the eager eyes of his lover Ctesippus, and others. The performance begins; and such a performance as might well seem to require an invocation of Memory and the Muses. It is agreed that the brothers shall question Cleinias. 'Cleinias,' says Euthydemus, 'who learn, the wise or the unwise?' 'The wise,' is the reply; given with blushing and hesitation. 'And yet when you learned you did not know and were not wise.' Then Dionysodorus takes up the ball: 'Who are they who learn dictation of the grammar-master; the wise or the foolish boys?' 'The wise.' 'Then, after all, the wise learn.' 'And do they learn,' said Euthydemus, 'what they know or what they do not know?' 'The latter.' 'And dictation is a dictation of letters?' 'Yes.' 'And you know letters?' 'Yes.' 'Then you learn what you know.' 'But,' retorts Dionysodorus, 'is not learning acquiring knowledge?' 'Yes.' 'And you acquire that which you have not got already?' 'Yes.' 'Then you learn that which you do not know.'
Socrates is afraid that the youth Cleinias may be discouraged at these repeated overthrows. He therefore explains to him the nature of the process to which he is being subjected. The two strangers are not serious; there are jests at the mysteries which precede the enthronement, and he is being initiated into the mysteries of the sophistical ritual. This is all a sort of horse-play, which is now ended. The exhortation to virtue will follow, and Socrates himself (if the wise men will not laugh at him) is desirous of showing the way in which such an exhortation should be carried on, according to his own poor notion. He proceeds to question Cleinias. The result of the investigation may be summed up as follows: —
All men desire good; and good means the possession of goods, such as wealth, health, beauty, birth, power, honour; not forgetting the virtues and wisdom. And yet in this enumeration the greatest good of all is omitted. What is that? Good fortune. But what need is there of good fortune when we have wisdom already: – in every art and business are not the wise also the fortunate? This is admitted. And again, the possession of goods is not enough; there must also be a right use of them which can only be given by knowledge: in themselves they are neither good nor evil – knowledge and wisdom are the only good, and ignorance and folly the only evil. The conclusion is that we must get 'wisdom.' But can wisdom be taught? 'Yes,' says Cleinias. The ingenuousness of the youth delights Socrates, who is at once relieved from the necessity of discussing one of his great puzzles. 'Since wisdom is the only good, he must become a philosopher, or lover of wisdom.' 'That I will,' says Cleinias.
After Socrates has given this specimen of his own mode of instruction, the two brothers recommence their exhortation to virtue, which is of quite another sort.
'You want Cleinias to be wise?' 'Yes.' 'And he is not wise yet?' 'No.' 'Then you want him to be what he is not, and not to be what he is? – not to be – that is, to perish. Pretty lovers and friends you must all be!'
Here Ctesippus, the lover of Cleinias, interposes in great excitement, thinking that he will teach the two Sophists a lesson of good manners. But he is quickly entangled in the meshes of their sophistry; and as a storm seems to be gathering Socrates pacifies him with a joke, and Ctesippus then says that he is not reviling the two Sophists, he is only contradicting them. 'But,' says Dionysodorus, 'there is no such thing as contradiction. When you and I describe the same thing, or you describe one thing and I describe another, how can there be a contradiction?' Ctesippus is unable to reply.
Socrates has already heard of the denial of contradiction, and would like to be informed by the great master of the art, 'What is the meaning of this paradox? Is there no such thing as error, ignorance, falsehood? Then what are they professing to teach?' The two Sophists complain that Socrates is ready to answer what they said a year ago, but is 'non-plussed' at what they are saying now. 'What does the word "non-plussed" mean?' Socrates is informed, in reply, that words are lifeless things, and lifeless things have no sense or meaning. Ctesippus again breaks out, and again has to be pacified by Socrates, who renews the conversation with Cleinias. The two Sophists are like Proteus in the variety of their transformations, and he, like Menelaus in the Odyssey, hopes to restore them to their natural form.
He had arrived at the conclusion that Cleinias must become a philosopher. And philosophy is the possession of knowledge; and knowledge must be of a kind which is profitable and may be used. What knowledge is there which has such a nature? Not the knowledge which is required in any particular art; nor again the art of the composer of speeches, who knows how to write them, but cannot speak them, although he too must be admitted to be a kind of enchanter of wild animals. Neither is the knowledge which we are seeking the knowledge of the general. For the general makes over his prey to the statesman, as the huntsman does to the cook, or the taker of quails to the keeper of quails; he has not the use of that which he acquires. The two enquirers, Cleinias and Socrates, are described as wandering about in a wilderness, vainly searching after the art of life and happiness. At last they fix upon the kingly art, as having the desired sort of knowledge. But the kingly art only gives men those goods which are neither good nor evil: and if we say further that it makes us wise, in what does it make us wise? Not in special arts, such as cobbling or carpentering, but only in itself: or say again that it makes us good, there is no answer to the question, 'good in what?' At length in despair Cleinias and Socrates turn to the 'Dioscuri' and request their aid.
Euthydemus argues that Socrates knows something; and as he cannot know and not know, he cannot know some things and not know others, and therefore he knows all things: he and Dionysodorus and all other men know all things. 'Do they know shoemaking, etc?' 'Yes.' The sceptical Ctesippus would like to have some evidence of this extraordinary statement: he will believe if Euthydemus will tell him how many teeth Dionysodorus has, and if Dionysodorus will give him a like piece of information about Euthydemus. Even Socrates is incredulous, and indulges in a little raillery at the expense of the brothers. But he restrains himself, remembering that if the men who are to be his teachers think him stupid they will take no pains with him. Another fallacy is produced which turns on the absoluteness of the verb 'to know.' And here Dionysodorus is caught 'napping,' and is induced by Socrates to confess that 'he does not know the good to be unjust.' Socrates appeals to his brother Euthydemus; at the same time he acknowledges that he cannot, like Heracles, fight against a Hydra, and even Heracles, on the approach of a second monster, called upon his nephew Iolaus to help. Dionysodorus rejoins that Iolaus was no more the nephew of Heracles than of Socrates. For a nephew is a nephew, and a brother is a brother, and a father is a father, not of one man only, but of all; nor of men only, but of dogs and sea-monsters. Ctesippus makes merry with the consequences which follow: 'Much good has your father got out of the wisdom of his puppies.'
'But,' says Euthydemus, unabashed, 'nobody wants much good.' Medicine is a good, arms are a good, money is a good, and yet there may be too much of them in wrong places. 'No,' says Ctesippus, 'there cannot be too much gold.' And would you be happy if you had three talents of gold in your belly, a talent in your pate, and a stater in either eye?' Ctesippus, imitating the new wisdom, replies, 'And do not the Scythians reckon those to be the happiest of men who have their skulls gilded and see the inside of them?' 'Do you see,' retorts Euthydemus, 'what has the quality of vision or what has not the quality of vision?' 'What has the quality of vision.' 'And you see our garments?' 'Yes.' 'Then our garments have the quality of vision.' A similar play of words follows, which is successfully retorted by Ctesippus, to the great delight of Cleinias, who is rebuked by Socrates for laughing at such solemn and beautiful things.
'But are there any beautiful things? And if there are such, are they the same or not the same as absolute beauty?' Socrates replies that they are not the same, but each of them has some beauty present with it. 'And are you an ox because you have an ox present with you?' After a few more amphiboliae, in which Socrates, like Ctesippus, in self-defence borrows the weapons of the brothers, they both confess that the two heroes are invincible; and the scene concludes with a grand chorus of shouting and laughing, and a panegyrical oration from Socrates: —
First, he praises the indifference of Dionysodorus and Euthydemus to public opinion; for most persons would rather be refuted by such arguments than use them in the refutation of others. Secondly, he remarks upon their impartiality; for they stop their own mouths, as well as those of other people. Thirdly, he notes their liberality, which makes them give away their secret to all the world: they should be more reserved, and let no one be present at this exhibition who does not pay them a handsome fee; or better still they might practise on one another only. He concludes with a respectful request that they will receive him and Cleinias among their disciples.
Crito tells Socrates that he has heard one of the audience criticise severely this wisdom, – not sparing Socrates himself for countenancing such an exhibition. Socrates asks what manner of man was this censorious critic. 'Not an orator, but a great composer of speeches.' Socrates understands that he is an amphibious animal, half philosopher, half politician; one of a class who have the highest opinion of themselves and a spite against philosophers, whom they imagine to be their rivals. They are a class who are very likely to get mauled by Euthydemus and his friends, and have a great notion of their own wisdom; for they imagine themselves to have all the advantages and none of the drawbacks both of politics and of philosophy. They do not understand the principles of combination, and hence are ignorant that the union of two good things which have different ends produces a compound inferior to either of them taken separately.
Crito is anxious about the education of his children, one of whom is growing up. The description of Dionysodorus and Euthydemus suggests to him the reflection that the professors of education are strange beings. Socrates consoles him with the remark that the good in all professions are few, and recommends that 'he and his house' should continue to serve philosophy, and not mind about its professors.
There is a stage in the history of philosophy in which the old is dying out, and the new has not yet come into full life. Great philosophies like the Eleatic or Heraclitean, which have enlarged the boundaries of the human mind, begin to pass away in words. They subsist only as forms which have rooted themselves in language – as troublesome elements of thought which cannot be either used or explained away. The same absoluteness which was once attributed to abstractions is now attached to the words which are the signs of them. The philosophy which in the first and second generation was a great and inspiring effort of reflection, in the third becomes sophistical, verbal, eristic.
It is this stage of philosophy which Plato satirises in the Euthydemus. The fallacies which are noted by him appear trifling to us now, but they were not trifling in the age before logic, in the decline of the earlier Greek philosophies, at a time when language was first beginning to perplex human thought. Besides he is caricaturing them; they probably received more subtle forms at the hands of those who seriously maintained them. They are patent to us in Plato, and we are inclined to wonder how any one could ever have been deceived by them; but we must remember also that there was a time when the human mind was only with great difficulty disentangled from such fallacies.