When he heard this he said: It seems so, Socrates, by what you say.
Then can it be, Hippocrates, that the sophist is really a sort of merchant or dealer in provisions on which a soul is nourished? For such is the view I take of him.
With what, Socrates, is a soul nourished?
With doctrines, presumably, I replied. And we must take care, my good friend, that the sophist, in commending his wares, does not deceive us, as both merchant and dealer do in the case of our bodily food. [313d] For among the provisions, you know, in which these men deal, not only are they themselves ignorant what is good or bad for the body, since in selling they commend them all, but the people who buy from them are so too, unless one happens to be a trainer or a doctor. And in the same way, those who take their doctrines the round of our cities, hawking them about to any odd purchaser who desires them, commend everything that they sell, and there may well be some of these too, my good sir, who are ignorant which of their wares is [313e] good or bad for the soul; and in just the same case are the people who buy from them, unless one happens to have a doctor's knowledge here also, but of the soul. So then, if you are well informed as to what is good or bad among these wares, it will be safe for you to buy doctrines from Protagoras or from anyone else you please: but if not, take care, my dear fellow, that you do not risk your greatest treasure on a toss of the dice.