and of reason formulated
by Plato and Aristotle. Much as these thinkers differed in many
respects, they agreed in identifying experience with purely practical
concerns; and hence with material interests as to its purpose and with
the body as to its organ. Knowledge, on the other hand, existed for its
own sake free from practical reference, and found its source and organ
in a purely immaterial mind; it had to do with spiritual or ideal
interests. Again, experience always involved lack, need, desire; it was
never self-sufficing. Rational knowing on the other hand, was complete
and comprehensive within itself. Hence the practical life was in a
condition of perpetual flux, while intellectual knowledge concerned
eternal truth.

This sharp antithesis is connected with the fact that Athenian
philosophy began as a criticism of custom and tradition as standards of
knowledge and conduct. In a search for something to replace them, it
hit upon reason as the only adequate guide of belief and activity. Since
custom and tradition were identified with experience, it followed at
once that reason was superior to experience. Moreover, experience, not
content with its proper position of subordination, was the great foe
to the acknowledgment of the authority of reason. Since custom and
traditionary beliefs held men in bondage, the struggle of reason for
its legitimate supremacy could be won only by showing the inherently
unstable and inadequate nature of experience. The statement of Plato
that philosophers should be kings may best be understood as a statement
that rational intelligence and not habit, appetite, impulse, and emotion
should regulate human affairs. The former secures unity, order, and law;
the latter signify multiplicity and discord, irrational fluctuations
from one estate to another.

The grounds for the identification of experience with the unsatisfactory
condition of things, the state of affairs represented by rule of mere
custom, are not far to seek. Increasing trade and travel, colonizations,
migrations and wars, had broadened the intellectual horizon. The customs
and beliefs of different communities were found to diverge sharply
from one another. Civil disturbance had become a custom in Athens;
the fortunes of the city seemed given over to strife of factions. The
increase of leisure coinciding with the broadening of the horizon had
brought into ken many new facts of nature and had stimulated curiosity
and speculation. T