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.'