CHAPTER IX The AtomistsTHE founders of atomism were two, Leucippus and Democritus. It is difficult to disentangle
them, because they are generally mentioned together, and apparently some of the works of
Leucippus were subsequently attributed to Democritus. Leucippus, who seems to have
flourished about 440 B.C., * came from Miletus, and carried on the scientific rationalist
philosophy associated with that city. He was much influenced by Parmenides and Zeno. So little
is known of him that Epicurus (a later follower of Democritus) was thought to have denied his
existence altogether, and some moderns have revived this theory. There are, however, a number
of allusions to him in Aristotle, and it seems incredible that these (which include textual
quotations) would have occurred if he had been merely a myth.
Democritus is a much more definite figure. He was a native of Abdera in Thrace; as for his
date, he stated that he was young when Anaxagoras was old, say about 432 B.C., and he is taken
to have flourished about 420 B.C. He travelled widely in southern and eastern lands in search of
knowledge; he perhaps spent a considerable time in Egypt, and he certainly visited Persia. He
then returned to Abdera, where he remained. Zeller calls him "superior to all earlier and
contemporary philosophers in wealth of knowledge, and to most in acuteness and logical
correctness of thinking."
Democritus was a contemporary of Socrates and the Sophists, and should, on purely
chronological grounds, be treated somewhat later in our history. The difficulty is that he is so
hard to separate from Leucippus. On this ground, I am considering him before Socrates
* Cyril Bailey, The Greek Atomists and Epicurus, estimates that he flourished about 430
B.C. or a little earlier.