For example, I may see a man who has eyes, nose, and mouth;--that will not
distinguish him from any other man. Or he may have a snub-nose and
prominent eyes;--that will not distinguish him from myself and you and
others who are like me. But when I see a certain kind of snub-nosedness,
then I recognize Theaetetus. And having this sign of difference, I have
knowledge. But have I knowledge or opinion of this difference; if I have
only opinion I have not knowledge; if I have knowledge we assume a disputed
term; for knowledge will have to be defined as right opinion with knowledge
of difference.

And so, Theaetetus, knowledge is neither perception nor true opinion, nor
yet definition accompanying true opinion. And I have shown that the
children of your brain are not worth rearing. Are you still in labour, or
have you brought all you have to say about knowledge to the birth? If you
have any more thoughts, you will be the better for having got rid of these;
or if you have none, you will be the better for not fancying that you know
what you do not know. Observe the limits of my art, which, like my
mother's, is an art of midwifery; I do not pretend to compare with the good
and wise of this and other ages.

And now I go to meet Meletus at the porch of the King Archon; but to-morrow
I shall hope to see you again, Theodorus, at this place.

...

I. The saying of Theaetetus, that 'Knowledge is sensible perception,' may
be assumed to be a current philosophical opinion of the age. 'The
ancients,' as Aristotle (De Anim.) says, citing a verse of Empedocles,
'affirmed knowledge to be the same as perception.' We may now examine
these words, first, with reference to their place in the history of