Over the past few years I've read a number of surveys of philosophy. In all of them, the pre-Socratics get the short shrift and each of them is generally boiled down to one idea. Thales was the "everything is made out of water" guy, Heraclitus was the "no man steps into the same river twice guy," and Democritus was the "the Universe is made out of atoms and the void" guy. In this little monograph Paul Cartledge tries to give us a more complete picture of Democritus. This is no easy task since his books are lost and his ideas exist only in fragments or in descriptions of them composed by other philosophers who disagreed with him on many points. The loss of his writings is a tragedy because, according to Cartledge, Democritus had a reputation as a very good writer, a rival of Plato even.
Cartledge puts Democritus in his historical context for us, and he fleshes out his ideas as much as is possible given the available sources. His concept of atoms and the void is indeed his most enduring contribution to both philosophy and science. (Richard Feynman once said that if all knowledge was about to be lost, and we could only pass one sentence of information on to the next generation, it should be this, "All things are made of atoms — little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another." In other words, the essence of Democritus.) But he also had interesting things to say on subjects like ethics, medicine, and politics.
Like the ideas of any pre-Socratic philosopher, some of what Democritus had to say now looks pretty ridiculous, but the best of his ideas have reverberated down the centuries. He not only inspired modern research into the fundamental building blocks of the universe, he also influenced materialist philosophy from Epicurus to the present day.
This little books was entertaining and enjoyable.