c.460 - 370 BC
Democritus was born in Thrace in northern Greece. He traveled widely, and he learned from his teacher, Leucippus, that everything is made of tiny particles.
Refining and elaborating Leucippus' ideas Democritus advanced the atomic theory, which asserted that the universe is composed of two indivisible elements, called the atom and the void. An infinite number of eternal and uncaused atoms differing from each other only in shape, arrangement, and magnitude, move through infinite space.
In theology Democritus attributed popular belief in the gods to a desire to explain extraordinary things (thunder or earthquakes) to superhuman entities.
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From the Internet Encyclopedia of Philosophy
University of St. Andrews, Scotland. School of Mathematics