Atomic theory," wrote Bernard Pullman, "is the most important and enduring legacy bequeathed by antiquity." Indeed, this the atomic theory provides a brilliant example of pure speculation which develops into a universally accepted scientific theory. First developed by the Greek philosophers Leucippus and his follower Democritus (c.430-c.370 b.c.), atomic theory remained purely speculative until the time, in the early twentieth century, when scientists started probing atomic structure through experimental methods. Furthermore, Greek atomism is a striking departure from other cosmogonic theories, such as the idea, suggested by Thales (c. 624-545 b.c.), that everything is derived from water, since atomism did not in any way rely on empirical observation.

Leucippus, who probably lived in the fifth century b.c. is widely considered as the father of atomic theory. Because no writings by Leucippus have come down to us (in fact Epicurus, a prominent atomist...