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?
STRANGER: Every discernment or discrimination of that kind, as I have observed, is called a purification.
THEAETETUS: Yes, that is the usual expression.
STRANGER: And any one may see that purification is of two kinds.
THEAETETUS: Perhaps so, if he were allowed time to think; but I do not see at this moment.
STRANGER: There are many purifications of bodies which may with propriety be comprehended under a single name.
THEAETETUS: What are they, and what is their name?