sense: Temperance is doing one's own business;--(4) is doing good.

Still an element of knowledge is wanting which Critias is readily induced
to admit at the suggestion of Socrates; and, in the spirit of Socrates and
of Greek life generally, proposes as a fifth definition, (5) Temperance is
self-knowledge. But all sciences have a subject: number is the subject of
arithmetic, health of medicine--what is the subject of temperance or
wisdom? The answer is that (6) Temperance is the knowledge of what a man
knows and of what he does not know. But this is contrary to analogy; there
is no vision of vision, but only of visible things; no love of loves, but
only of beautiful things; how then can there be a knowledge of knowledge?
That which is older, heavier, lighter, is older, heavier, and lighter than
something else, not than itself, and this seems to be true of all relative
notions--the object of relation is outside of them; at any rate they can
only have relation to themselves in the form of that object. Whether there
are any such cases of reflex relation or not, and whether that sort of
knowledge which we term Temperance is of this reflex nature, has yet to be
determined by the great metaphysician. But even if knowledge can know
itself, how does the knowledge of what we know imply the knowledge of what
we do not know? Besides, knowledge is an abstraction only, and will not
inform us of any particular subject, such as medicine, building, and the
like. It may tell us that we or other men know something, but can never
tell us what we know.

Admitting that there is a knowledge of what we know and of what we do not
know, which would supply a rule and measure of all things, still there
would be no good in this; and the knowledge which temperance gives must be
of a kind which will do us good; for temperance is a good. But this
universal knowledge does not tend to our happiness and good: the only kind
of knowledge which brings happiness is the knowledge of good and evil. To