life prevented him from speaking in the Assembly (Mem.); and we are
surprised to hear that, like Critias, he afterwards became one of the
thirty tyrants. In the Dialogue he is a pattern of virtue, and is
therefore in no need of the charm which Socrates is unable to apply. With
youthful naivete, keeping his secret and entering into the spirit of
Socrates, he enjoys the detection of his elder and guardian Critias, who is
easily seen to be the author of the definition which he has so great an
interest in maintaining. The preceding definition, 'Temperance is doing
one's own business,' is assumed to have been borrowed by Charmides from
another; and when the enquiry becomes more abstract he is superseded by
Critias (Theaet.; Euthyd.). Socrates preserves his accustomed irony to the
end; he is in the neighbourhood of several great truths, which he views in
various lights, but always either by bringing them to the test of common
sense, or by demanding too great exactness in the use of words, turns aside
from them and comes at last to no conclusion.

The definitions of temperance proceed in regular order from the popular to
the philosophical. The first two are simple enough and partially true,
like the first thoughts of an intelligent youth; the third, which is a real
contribution to ethical philosophy, is perverted by the ingenuity of
Socrates, and hardly rescued by an equal perversion on the part of Critias.
The remaining definitions have a higher aim, which is to introduce the
element of knowledge, and at last to unite good and truth in a single
science. But the time has not yet arrived for the realization of this
vision of metaphysical philosophy; and such a science when brought nearer
to us in the Philebus and the Republic will not be called by the name of
(Greek). Hence we see with surprise that Plato, who in his other writings
identifies good and knowledge, here opposes them, and asks, almost in the
spirit of Aristotle, how can there be a knowledge of knowledge, and even if
attainable, how can such a knowledge be of any use?