=The Life of Democritus= (460–370 B. C.). Democritus was twenty years younger than Protagoras, about ten years younger than Socrates, and a generation older than Plato. He was outlived by Plato; and Aristotle was a young man when Democritus died. He was therefore contemporary with the intellectual movement going on in Greece, with Athens as a centre. While he does not appear to have come under the influence of Socrates, he was well acquainted with the destructive epistemology of the Sophists. Abdera, where he lived, is in Thrace, and seems to have been outside the Anthropological movement at Athens. The school of Leucippus was at Abdera; and Democritus was instructed in the Sophistic doctrine directly from Protagoras, who was a member of the Atomistic school before going to Athens. The three Systematic philosophers were wide travelers, Democritus not less than Plato and Aristotle. He traveled extensively through Greece, Egypt, and the Orient. He then returned to Abdera and began his scientific activity. He remained five years in Egypt, and came to know the greater part of western Asia. He returned to Abdera about 420 B. C., and therefore did not begin his teaching before he was forty years old. The length of time that Democritus, Plato, and Aristotle took for their apprenticeship, and the advanced age before they began their mastership, is remarkable. Democritus was the greatest investigator of nature in antiquity, and Aristotle used much of Democritus’ work for his own scientific writings. The ancients admired the writings of Democritus, and the loss of them in the fourth century after Christ is one of the most lamentable that has happened to the literary documents of antiquity. His works were extraordinary in number, and upon every known subject. Democritus was the real exponent of the Atomistic school. The founder, Leucippus, belonged to the Cosmological Period; Protagoras, the Sophist, belonged to the Anthropological Period, and had great influence in the development of the school at Abdera; but Democritus, in systematizing the doctrines of Leucippus and in accepting the perception theory of Protagoras, became its most notable representative. He was the great systematizer of the Cosmologists, and yet he differed from all the Cosmologists in embodying in his theory the results of the Sophistic movement.