at each moment. (In modern
language, the act of sensation is really indivisible, though capable of
a mental analysis into subject and object.) My sensation alone is true,
and true to me only. And therefore, as Protagoras says, "To myself I
am the judge of what is and what is not." Thus the flux of Homer and
Heracleitus, the great Protagorean saying that "Man is the measure of
all things," the doctrine of Theaetetus that "Knowledge is perception,"
have all the same meaning. And this is thy new-born child, which by my
art I have brought to light; and you must not be angry if instead of
rearing your infant we expose him.'

'Theaetetus will not be angry,' says Theodorus; 'he is very
good-natured. But I should like to know, Socrates, whether you mean to
say that all this is untrue?'

'First reminding you that I am not the bag which contains the arguments,
but that I extract them from Theaetetus, 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 sensations are always true, 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 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? My own art of midwifery, and all dialectic, is
an enormous folly, if Protagoras' "Truth" be indeed truth, and the
philosopher is not merely amusing himself by giving oracles out of his
book.'

Theodorus thinks that Socrates is unjust to his master, Protagoras; but
he is too old and stiff to try a fall with him, and therefore refers him
to Theaetetus, who is already driven out of his former opinion by the
arguments of Socrates.

Socrates then takes up the defence of Protagoras, who is supposed to
reply in his own person--'Good people, you sit and declaim about the
gods, of whose existence or non-existence I have nothing to say, or you
discourse about man being reduced to the level of the brutes; but what
proof have you of your statements? A