"If your body had been in a critical condition you would have asked the advice of your friends and deliberated many days before choosing your doctor. But about your mind, on which depends your weal or woe according as it is evil or good, you never asked the advice of father or friend whether you ought to apply to this newly-arrived stranger. Hearing last night that he was here, you go to him to-day, ready to spend your own and your friends' money, convinced that you ought to become a disciple of a man you neither know nor have talked with." They proceed to the house of Callias, where they find Protagoras surrounded by strangers from every city who listened spell-bound to his voice. Protagoras readily promises that Hippocrates would be taught his system which offers "good counsel about his private affairs and power to transact and discuss political matters". Socrates' belief that politics cannot be taught provokes one of the long speeches to which Plato strongly objected because a fundamental fallacy could not be refuted at the outset, vitiating the whole of the subsequent argument. Protagoras recounted a myth, proving that shame and justice were given to every man; these are the basis of politics. Further, cities punish criminals, implying that men can learn politics, while virtue is taught by parents and tutors and the State. Socrates asks whether virtue is one or many. Protagoras replies that there are five main virtues, knowledge, justice, courage, temperance and piety, all distinct. A long rambling speech causes Socrates to protest; his method is the short one of question and answer. By using some very questionable reasoning he proves that all these five virtues are identical. Accordingly, if virtue is one it can be taught, not however, by a sophist or the State, but by a philosopher, for virtue is knowledge. This conclusion is thoroughly in harmony with Socrates' system. Yet it is probably false. Virtue is not mere knowledge, nor vice ignorance. If they were, they would be intellectual qualities. They are rather moral attributes; experience soon proves that many enlightened persons are vicious and many ignorant people virtuous. The value of this dialogue is its insistence upon the unity of virtue. A good man is not a bundle of separate excellences; he is a whole. Possessing one virtue he potentially has them all.