on, practice, and habit. The consequence is
that a man's character does not change very much as he grows older. By
constant practice, by continual self-control, a man may, to some
extent, make himself better, but on the whole, what he is he remains.
The leopard, we say, does not change his spots. But as, for Socrates,
the sole condition of virtue is knowledge, and as knowledge is just
what can be imparted by teaching, it followed that virtue must be
teachable. The only difficulty is to find the teacher, to find some
one who knows the concept of virtue. What the concept of virtue
is--that is, thought Socrates, the precious piece of knowledge, which
no philosopher has ever discovered, and which, if it were only
discovered, could at once be imparted by teaching, whereupon men would
at once become virtuous.

The other Socraticism is that "virtue is one." We talk of many
virtues, temperance, prudence, foresight, benevolence, kindness, etc.
Socrates believed that all these particular virtues flowed from the
one source, knowledge. Therefore knowledge itself, that is to say,
wisdom, is the sole virtue, and this includes all the others.

This completes the exposition of the positive teaching of Socrates. It
only remains for us to consider what position Socrates holds in the
history of thought. There are two sides of the Socratic teaching. In
the first {150} place, there is the doctrine of knowledge, that all
knowledge is through concepts. This is the scientific side of the
philosophy of Socrates. Secondly, there is his ethical teaching. Now
the essential and important side of Socrates is undoubtedly the
scientific theory of concepts. It is this which gives him his position
in the history of philosophy. His ethical ideas, suggestive as they
were, were yet all tainted with the fallacy that men are governed only
by reason. Hence they have exercised no great influence on the history
of thought. But the theory of concepts worked a revolution in
philosophy. Upon a development of it is founded the whole of Plato's
philosophy, and, through Plato, the philosophy of Aristotle, and,
indeed, all subsequent idealism. The immediate effect of this theory,
however, was the destruction of the teaching of the Sophists. The
Sophists taught the doctrine that truth is sense-perception, and as
the perceptions of different individuals differ in regard to the same
object, it followed that truth became a matter of taste with the
individual. This under