if knowledge is perception, how
can we distinguish between the true and the false in such cases? . . .
Shall I tell you what amazes me in your friend Protagoras? 'What may
that be?' I like his doctrine that what appears is; but I wonder that
he did not begin his great work on truth with a declaration that a pig,
or a dog-faced baboon, or any other monster which has sensation, is a
measure of all things; then while we were reverencing him as a god he
might have produced a magnificent effect by expounding to us that he
was no wiser than a tadpole. For if truth is only sensation, and one
man's discernment is as good as another's, and every man is his own
judge, and everything that he judges is right and true, then {90} what
need of Protagoras to be our instructor at a high figure; and why
should we be less knowing than he is, or have to go to him, if every
man is the measure of all things?" . . . Socrates now resumes the
argument. As he is very desirous of doing justice to Protagoras, he
insists on citing his own words: 'What appears to each man is to him.'
"And how," asks Socrates, "are these words reconcilable with the fact
that all mankind are agreed in thinking themselves wiser than others in
some respects, and inferior to them in others? In the hour of danger
they are ready to fall down and worship any one who is their superior
in wisdom as if he were a god. And the world is full of men who are
asking to be taught and willing to be ruled, and of other men who are
willing to rule and teach them. All which implies that men do judge of
one another's impressions, and think some wise and others foolish. How
will Protagoras answer this argument? For he cannot say that no one
deems another ignorant or mistaken. If you form a judgment, thousands
and tens of thousands are ready to maintain the opposite. The
multitude may not and do not agree in Protagoras' own thesis, 'that man
is the measure of all things,' and then who is to decide? Upon hip own
showing must not his 'truth' depend on the number of suffrages, and be
more or less true in proportion as he has more or fewer of them? And
{91} [the majority being against him] he will be bound to acknowledge
that they speak truly who deny him to speak truly, which is a famous
jest. And if he admits that they speak truly who deny him to speak
truly, he must admit that he himself does not speak truly. But his
opponents will refuse to admit this as regards themselves, a