In the _Lysis_ the characters and the conclusion are similar. Lysis is a young lad admired by Hippothales. The first portion of the dialogue consists of a conversation between Lysis and Socrates; the latter recommends the admirer to avoid foolish converse. On the entry of Lysis' friend Menexenus, Socrates starts the question "What is friendship?" It appears that friendship cannot exist between two good or two evil persons, but only between a good man and one who is neither good nor bad, exactly as the philosopher is neither wise nor ignorant, yet he loves knowledge. Still this is not satisfactory; up conclusion being reached, Socrates winds up with a characteristic remark; they think they are friends, yet cannot say what friendship is. This dialogue was carefully read by Aristotle before he gave his famous description in the Ethics: "A friend is a second self". Perhaps Socrates avoided a definite answer because he did not wish to be too serious with these sunny children. The _Euthydemus_ is an amusing study of the danger which follows upon the use of keen instruments by the unscrupulous. Euthydemus and his brother Dionysodorus are two sophists by trade to whom words mean nothing at all; truth and falsehood are identical, contradiction being an impossibility. As language is meaningless, Socrates himself is quickly reduced to impotence, recovering with difficulty. Plato was no doubt satirising the misuse of the new philosophy which was becoming so popular with young men. When nothing means anything, laughter is the only human language left. The _Cratylus_ is a similarly conceived diversion. Most of it is occupied with fanciful derivations and linguistic discussions of all kinds. It is difficult to say how far Plato is serious. Perhaps the feats of Euthydemus in stripping words of all meaning urged him to some constructive work--for Plato's system is essentially destructive first, then constructive. At any rate, he does insist on the necessity for determining a word's meaning by its derivation, and points out that a language is the possession of a whole people. In the _Protagoras_ Socrates while a young man is represented as meeting a friend Hippocrates, who was on his way to Protagoras, a sophist from Abdera who had just arrived at Athens. Socrates shows first that his friend has no idea of the seriousness of his action in applying for instruction to a sophist whose definition he is unable to give.