Democritus (460-360 B.C.E.) ... was the first full-fledged materialist. [His view was that EVERYTHING, including thinking itself, was made of atoms and their motions.] Democritus, like Protagoras, was born in Abdera, Thrace. He was about twenty years younger than Protagoras and ten years younger than Socrates. Although he lived to be 100 years old and overlapped with the young Plato, the latter makes no mention of him in any of his work. (Democritus was seventy-five when Plato wrote his Symposium. ) Not only does Democritus' name not appear anywhere, Plato makes no mention of the atomic theory. This is especially odd since Plato's star pupil and philosophical successor, Aristotle (who, like Democritus, was a northern Ionian), wrote knowingly about him. Democritus himself wrote that while Protagoras received a great welcome upon his arrival in Athens, "I went to Athens, and no one knew me." One possible clue comes from the ancient biographer Diogenes Laertius (on whom most of the biographical and source material on the pre-Socratic philosophers is based), who claimed that Plato so despised Democritus that he would have liked to see all his books burned.
What we do know with some confidence is that he was as prolific a writer as Plato. He had over fifty books to his credit, all of which were destroyed between the third and fifth centuries C.E. (Common Era).
