are commonly used in argument, he may be involved even in greater
paradoxes than these. Shall I explain this matter to you or to
Theaetetus?

  Theod. To both of us, and let the younger answer; he will incur less
disgrace if he is discomfited.

  Soc. Then now let me ask the awful question, which is this:-Can a
man know and also not know that which he knows?

  Theod. How shall we answer, Theaetetus?

  Theaet. He cannot, I should say.

  Soc. He can, if you maintain that seeing is knowing. When you are
imprisoned in a well, as the saying is, and the self-assured adversary
closes one of your eyes with his hand, and asks whether you can see
his cloak with the eye which he has closed, how will you answer the
inevitable man?

  Theaet. I should answer, "Not with that eye but with the other."

  Soc. Then you see and do not see the same thing at the same time.

  Theaet. Yes, in a certain sense.

  Soc. None of that, he will reply; I do not ask or bid you answer
in what sense you know, but only whether you know that which you do
not know. You have been proved to see that which you do not see; and
you have already admitted that seeing is knowing, and that
not-seeing is not-knowing: I leave you to draw the inference.

  Theaet. Yes, the inference is the contradictory of my assertion.

  Soc. Yes, my marvel, and there might have been yet worse things in
store for you, if an opponent had gone on to ask whether you can
have a sharp and also a dull knowledge, and whether you can know near,
but not at a distance, or know the same thing with more or less
intensity, and so on without end. Such questions might have been put
to you by a light-armed mercenary, who argued for pay. He would have
lain in wait for you, and when you took up the position, that sense is
knowledge, he would have made an assault upon hearing, smelling, and
the other senses;-he would have shown you no mercy; and while you were
lost in envy and admiration of his wisdom, he would have got you
into his net, out of which you would not have escaped until you had
come to an understanding about the sum to be paid for your release.
Well, you ask, and how will Protagoras reinforce his position? Shall I
answer for him?

  Theaet. By all means.