Plato, Protagoras

[314a] For I tell you there is far more serious risk in the purchase of doctrines than in that of eatables. When you buy victuals and liquors you can carry them off from the dealer or merchant in separate vessels, and before you take them into your body by drinking or eating you can lay them in your house and take the advice of an expert whom you can call in, as to what is fit to eat or drink and what is not, and how much you should take and when; so that in this purchase the risk is not serious. [314b] But you cannot carry away doctrines in a separate vessel: you are compelled, when you have handed over the price, to take the doctrine in your very soul by learning it, and so to depart either an injured or a benefited man. These, then, are questions which we have to consider with the aid of our elders, since we ourselves are still rather young to unravel so great a matter. For the moment, however, let us pursue our design and go and hear this person; and when we have heard him we shall proceed to consult others: for Protagoras is not the only one there; we shall find Hippias of Elis [314c] and, I believe, Prodicus of Ceos, and numerous other men of wisdom besides.

This we resolved on, and set forth; and when we arrived at the doorway, we stood discussing some question or other that had occurred to us by the way: so, not to leave it unfinished, but to get it settled before we went in, we stood there and discussed in front of the door, until we had come to an agreement with each other. Now, I fancy the doorkeeper, who was a eunuch, overheard us; very likely [314d] the great number of sophists has made him annoyed with callers at the house: at any rate, when we had knocked on the door, he opened it and, on seeing us,—Hullo, he said, sophists there! Master is engaged. So saying, he seized the door with both hands and very smartly clapped it to with all his might. We tried knocking again, and then he spoke in answer through the closed door,—Sirs, have you not heard, he is engaged? But, my good fellow, I said, we have not come to see Callias, [314e] nor are we sophists. Have no fear: I tell you, we have come to ask if we may see Protagoras; so go and announce us. Then with much hesitation the fellow opened the door to us and when we had entered, we came upon Protagoras as he was walking round in the cloister,¹ and close behind him two companies were walking round also; on the one side Callias, son of Hipponicus and his brother on the mother's side,