THEODORUS: What is it?

SOCRATES: I am charmed with his doctrine, that what appears is to each
one, but I wonder that he did not begin his book on Truth with a
declaration that a pig or a dog-faced baboon, or some other yet stranger
monster which has sensation, is the measure of all things; then he might
have shown a magnificent contempt for our opinion of him by informing us at
the outset that while we were reverencing him like a God for his wisdom he
was no better than a tadpole, not to speak of his fellow-men--would not
this have produced an overpowering effect? For if truth is only sensation,
and no man can discern another's feelings better than he, or has any
superior right to determine whether his opinion is true or false, but each,
as we have several times repeated, is to himself the sole judge, and
everything that he judges is true and right, why, my friend, should
Protagoras be preferred to the place of wisdom and instruction, and deserve
to be well paid, and we poor ignoramuses have to go to him, if each one is
the measure of his own wisdom? Must he not be talking 'ad captandum' in
all this? I say nothing of the ridiculous predicament in which my own
midwifery and the whole art of dialectic is placed; for the attempt to
supervise or refute the notions or opinions of others would be a tedious
and enormous piece of folly, if to each man his own are right; and this
must be the case if Protagoras' Truth is the real truth, and the
philosopher is not merely amusing himself by giving oracles out of the
shrine of his book.

THEODORUS: He was a friend of mine, Socrates, as you were saying, and
therefore I cannot have him refuted by my lips, nor can I oppose you when I
agree with you; please, then, to take Theaetetus again; he seemed to answer
very nicely.