The Pythagoreans attempted to solve the problem raised by Heraclitus and Parmenides by postulating two worlds: one in constant ﬂux, this world; and one eternal and immutable, the world of number. The Atomists attempted a very different reconciliation. In the process, they made possible the birth of modern science. They also caused the destruction of the mind.
The Atomists belonged to a general approach called pluralism. The Pluralists agreed with Parmenides that there was only one eternal and unchanging stuff making up reality. But they also agreed with Heraclitus that change was simply too obvious a fact to deny. So they postulated that not one, but many stuffs populated the world — not monism but pluralism — each of them like a miniature Parmenidean universe. They then explained every kind of change as simply the spatial rearrangement of these unchanging stuffs.
The first pluralist was Empedocles, who said there were four elements, four “roots”: earth, air, water, and ﬁre. Anaxagoras came afterwards and he was not satisfied with this explanation. If “nothing new under the sun” could ever appear, then four stuffs won’t suffice. His solution was that “little seeds” — of as many different stuffs as there are different types of things — were actually in everything. That way, mere rearrangement could now work.
Thales wanted to ﬁnd the one in the many; the Pluralists were satisfied with the many as absolutely irreducible and inexplicable.
The atomists, Leucippus and Democritus, found a half-way solution between Parmenidean monism and Anaxagoras’ pluralism. All reality is indeed formed by the rearrangements of tiny, irreducible particles which they called “atoms” (from the Greek atomon, for “uncuttable”). But there was no need for “seeds” of all the qualities we observe; these are simply subjective effects on human beings, merely the way things appear to us. No qualities like colors, sounds, odors or textures are real. All that truly exist are the quantitative characteristics of things, their size, shape, number and state of motion. As always, the senses are deceptive. This distinction between “quantities” and “qualities”, was picked up by and accepted by Galileo, Descartes, Spinoza, Leibnitz, and finally Locke, who gave it its modern name (“primary” versus “secondary” qualities).
But, like all philosophers across history (Peikoff would no doubt exclude Ayn Rand from this assertion), the Atomists were not fully consistent. For the plurality of atoms to exist there had to be empty spaces between them — the void. So, there were in fact two stuffs in reality: that which is, and that which is not, a blatant violation of Parmenides’ principle. The atomists solved one problem and created another.
Another highly influential consequence of the atomists’ philosophy was the rise of determinism. Everything is determined by the atomic conﬁgurations and the various pressures and reactions that the atoms are submitted. “Materialism” states that anything nonmaterial is simply a derivative or byproduct to be explained entirely in physical terms. “Mechanicism” is the view that everything happens according to the laws of mechanics. Nothing ever happens by chance. Nothing ever happens for a purpose. It follows, therefore, that man is governed by strict determinism. Determinism is implied by materialism, because everything being material there’s no mind to make any choices; and it’s implied by mechanicism, because everything happens according to laws, not to free will of any kind. The atomists were the ﬁrst determinists in philosophic history.
Modern science can be said to have begun when somebody got the idea of combining Democritus with Pythagoras, of looking for mechanistic laws which were mathematically formulable. But as a metaphysics, this idea is completely invalid, because it denies the existence of mind.