Theaetetus: Yes.
Stranger: And that which exchanges the goods of one city for those of another by selling and buying is the exchange of the merchant?
Theaetetus: To be sure.
Stranger: And you are aware that this exchange of the merchant is of two kinds: it is partly concerned with food for the use of the body, and partly with the food of the soul which is bartered and received in exchange for money.
Theaetetus: What do you mean?
Stranger: You want to know what is the meaning of food for the soul; the other kind you surely understand.
Theaetetus: Yes.
Stranger: Take music in general and painting and marionette playing and many other things, which are purchased in one city, and carried away and sold in another—wares of the soul which are hawked about either for the sake of instruction or amusement;—may not he who takes them about and sells them be quite as truly called a merchant as he who sells meats and drinks?
Theaetetus: To be sure he may.
Stranger: And would you not call by the same name him who buys up knowledge and goes about from city to city exchanging his wares for money?
Theaetetus: Certainly I should.
Stranger: Of this merchandise of the soul, may not one part be fairly termed the art of display? And there is another part which is certainly not less ridiculous, but being a trade in learning must be called by some name germane to the matter?
Theaetetus: Certainly.
Stranger: The latter should have two names—one descriptive of the sale of the knowledge of virtue, and the other of the sale of other kinds of knowledge.
Theaetetus: Of course.
Stranger: The name of art-seller corresponds well enough to the latter; but you must try and tell me the name of the other.
Theaetetus: He must be the Sophist, whom we are seeking; no other name can possibly be right.
Stranger: No other; and so this trader in virtue again turns out to be our friend the Sophist, whose art may now be traced from the art of acquisition through exchange, trade, merchandise, to a merchandise of the soul which is concerned with speech and the knowledge of virtue.
Theaetetus: Quite true.
Stranger: And there may be a third reappearance of him;—for he may have settled down in a city, and may fabricate as well as buy these same wares, intending to live by selling them, and he would still be called a Sophist?
Theaetetus: Certainly.
Stranger: Then that part of the acquisitive art which exchanges, and of exchange which either sells a man’s own productions or retails those of others, as the case may be, and in either way sells the knowledge of virtue, you would again term Sophistry?
Theaetetus: I must, if I am to keep pace with the argument.
Stranger: Let us consider once more whether there may not be yet another aspect of sophistry.
Theaetetus: What is it?