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. The situation tended to raise the question as to the existence of anything constant and universal in the realm of nature and society. Reason was the faculty by which the universal principle and essence is apprehended; while the senses were the organs of perceiving change,—the unstable and the diverse as against the permanent and uniform. The results of the work of the senses, preserved in memory and imagi-
