In this second period of its history Greek philosophy reaches its
highest development. It is a comparatively short period, being
comprised within the life spans of the three men who so dominated the
philosophic thought of their age that their names, rather than the
names of schools or cities, are used to mark off the three subdivisions
into which the study of the period naturally falls. We shall,
I. Socrates and the imperfectly Socratic Schools.
II. Plato and the Academics.
III. Aristotle and the Peripatetics.
The problem with which this period had to deal had already been
formulated by the Sophists, -- how to save the intellectual and moral
life of the nation, which was threatened by materialism and scepticism.
Socrates answered by determining the conditions of intellectual
knowledge, and by laying deep the scientific foundation of ethics.
Plato, with keener insight and more comprehensive understanding,
developed the Socratic doctrine of concepts into a system of
metaphysics, gigantic in its proportions, but lacking in that solidity
of foundation which characterized the Aristotelian structure. Aristotle
carried the Socratic idea to its highest perfection, and, by
prosecuting a vigorous and systematic study of nature, supplied what
was defective in Plato's metaphysical scheme. The central problem was
always the same; the answer was also the same, though in different
degrees of organic development, -- concept, Idea, essence. The
view adopted was neither entirely subjective nor entirely objective,
-- the concept doctrine, which was the first and simplest answer, being
the typical formula for the union of subject and object, of self and