with the flux observed, and mechanism conceived to explain it, the
theory of existence is complete; and had a complete physical theory been
incorporated into the Socratic philosophy, wisdom would have lacked none
of its parts. Democritus, however, appeared too late, when ideal science
had overrun the whole field and initiated a verbal and dialectical
physics; so that Aristotle, for all his scientific temper and studies,
built his natural philosophy on a lamentable misunderstanding, and
condemned thought to confusion for two thousand years.

[Sidenote: Socrates and the autonomy of mind.]

If the happy freedom of the Greeks from religious dogma made them the
first natural philosophers, their happy political freedom made them the
first moralists. It was no accident that Socrates walked the Athenian
agora; it was no petty patriotism that made him shrink from any other
scene. His science had its roots there, in the personal independence,
intellectual vivacity, and clever dialectic of his countrymen. Ideal
science lives in discourse; it consists in the active exercise of
reason, in signification, appreciation, intent, and self-expression. Its
sum total is to know oneself, not as psychology or anthropology might
describe a man, but to know, as the saying is, one's own mind. Nor is he
who knows his own mind forbidden to change it; the dialectician has
nothing to do with future possibilities or with the opinion of anyone
but the man addressed. This kind of truth is but adequate veracity; its
only object is its own intent. Having developed in the spirit the
consciousness of its meanings and purposes, Socrates rescued logic and
ethics for ever from authority. With his friends the Sophists, he made
man the measure of all things, after bidding him measure himself, as
they neglected to do, by his own ideal. That brave humanity which had
first raised its head in Hellas and had endowed so many things in heaven