given by Prometheus (who stole them), whereas justice and reverence and the
political virtues could only be imparted by Zeus; (8) in the latter part of
the Dialogue, when Socrates is arguing that 'pleasure is the only good,'
Protagoras deems it more in accordance with his character to maintain that
'some pleasures only are good;' and admits that 'he, above all other men,
is bound to say "that wisdom and knowledge are the highest of human
things."'

There is no reason to suppose that in all this Plato is depicting an
imaginary Protagoras; he seems to be showing us the teaching of the
Sophists under the milder aspect under which he once regarded them. Nor is
there any reason to doubt that Socrates is equally an historical character,
paradoxical, ironical, tiresome, but seeking for the unity of virtue and
knowledge as for a precious treasure; willing to rest this even on a
calculation of pleasure, and irresistible here, as everywhere in Plato, in
his intellectual superiority.

The aim of Socrates, and of the Dialogue, is to show the unity of virtue.
In the determination of this question the identity of virtue and knowledge
is found to be involved. But if virtue and knowledge are one, then virtue
can be taught; the end of the Dialogue returns to the beginning. Had
Protagoras been allowed by Plato to make the Aristotelian distinction, and
say that virtue is not knowledge, but is accompanied with knowledge; or to
point out with Aristotle that the same quality may have more than one
opposite; or with Plato himself in the Phaedo to deny that good is a mere
exchange of a greater pleasure for a less--the unity of virtue and the
identity of virtue and knowledge would have required to be proved by other
arguments.

The victory of Socrates over Protagoras is in every way complete when their