History of Western Philosophy - Bertrand Russell [42]
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 and the Sophists, although part of his philosophy was intended as an answer to Protagoras, his fellowtownsman and the most eminent of the Sophists. Protagoras, when he visited Athens, was received enthusiastically; Democritus, on the other hand, says: 'I went to Athens, and no one knew me.' For a long time, his philosophy was ignored in Athens; 'It is not clear,' says Burnet, 'that Plato knew anything about Democritus…. Aristotle, on the other hand, knows Democritus well; for he too was an Ionian from the North.'2
Plato never mentions him in the Dialogues, but is said by Diogenes Laertius to have disliked him so much that he wished all his books burnt. Heath esteems him highly as a mathematician.3
The fundamental ideas of the common philosophy of Leucippus and Democritus were due to the former, but as regards the working out it is hardly possible to disentangle them, nor is it, for our purposes, important to make the attempt. Leucippus, if not Democritus, was led to atomism in the attempt to mediate between monism and pluralism, as represented by Parmenides and Empedocles respectively. Their point of view was remarkably like that of modern science, and avoided most of the faults to which Greek speculation was prone. They believed that everything is composed of atoms, which are physically, but not geometrically, indivisible; that between the atoms there is empty space; that atoms are indestructible; that they always have been, and always will be, in motion; that there are an infinite number of atoms, and even of kinds of atoms, the differences being as regards shape and size. Aristotle4 asserts that, according to the atomists, atoms also differ as regards heat, the spherical atoms, which compose fire, being the hottest; and as regards weight, he quotes Democritus as saying 'The more any indivisible exceeds, the heavier it is.' But the question whether atoms are originally possessed of weight in the theories of the atomists is a controversial one.
The atoms were always in motion, but there is disagreement among commentators as to the character of the original motion. Some, especially Zeller, hold that the atoms were thought to be always falling, and that the heavier ones fell faster; they thus caught up the lighter ones, there were impacts, and the atoms were deflected like billiard balls. This was certainly the view of Epicurus, who in most respects based his theories on those of Democritus, while trying, rather unintelligently, to take account of Aristotle's criticisms. But there is considerable reason to think that weight was not an original property of the atoms of Leucippus and Democritus. It seems more probable that, on their view, atoms were originally moving at random, as in the modern kinetic theory of gases. Democritus said there was neither up nor down
in the infinite void, and compared the movement of atoms in the soul to that of motes in a sunbeam when there is no wind. This is a much more intelligent view than that