Theaetetus: That is the common name for it.
Stranger: But now who the other is, who makes money out of private disputation, it is your turn to say.
Theaetetus: There is only one true answer: he is the wonderful Sophist, of whom we are in pursuit, and who reappears again for the fourth time.
Stranger: Yes, and with a fresh pedigree, for he is the moneymaking species of the Eristic, disputatious, controversial, pugnacious, combative, acquisitive family, as the argument has already proven.
Theaetetus: Certainly.
Stranger: How true was the observation that he was a many-sided animal, and not to be caught with one hand, as they say!
Theaetetus: Then you must catch him with two.
Stranger: Yes, we must, if we can. And therefore let us try another track in our pursuit of him: You are aware that there are certain menial occupations which have names among servants?
Theaetetus: Yes, there are many such; which of them do you mean?
Stranger: I mean such as sifting, straining, winnowing, threshing.
Theaetetus: Certainly.
Stranger: And besides these there are a great many more, such as carding, spinning, adjusting the warp and the woof; and thousands of similar expressions are used in the arts.
Theaetetus: Of what are they to be patterns, and what are we going to do with them all?
Stranger: I think that in all of these there is implied a notion of division.
Theaetetus: Yes.
Stranger: Then if, as I was saying, there is one art which includes all of them, ought not that art to have one name?
Theaetetus: And what is the name of the art?
Stranger: The art of discerning or discriminating.
Theaetetus: Very good.
Stranger: Think whether you cannot divide this.
Theaetetus: I should have to think a long while.
Stranger: In all the previously named processes either like has been separated from like or the better from the worse.
Theaetetus: I see now what you mean.
Stranger: There is no name for the first kind of separation; of the second, which throws away the worse and preserves the better, I do know a name.
Theaetetus: What is it?