SOCRATES: Can a man see something and yet see nothing?
THEAETETUS: Impossible.
SOCRATES: But if he sees any one thing, he sees something that exists. Do you suppose that what is one is ever to be found among non-existing things?
THEAETETUS: I do not.
SOCRATES: He then who sees some one thing, sees something which is?
THEAETETUS: Clearly.
SOCRATES: And he who hears anything, hears some one thing, and hears that which is?
THEAETETUS: Yes.
SOCRATES: And he who touches anything, touches something which is one and therefore is?
THEAETETUS: That again is true.