Atomism has been described as “the crown of Greek philosophical achievement before Plato.” It was the invention of two philosophers of the 5th century BC: Leucippus and Democritus.
Not much is known about Leucippus, though he is usually credited with having worked out the basics of the theory of atomism. His younger associate Democritus was born around 460BC in Abdera in northern Greece, shortly after Socrates was born in Athens.
He was a prolific author, with over 50 works to his name, and he was known in antiquity as the “laughing philosopher” because of the value he placed on euthymia or cheerfulness. But he is best known for developing various aspects of the atomic theory.
In the atomic universe, everything we observe ultimately consists of “atoms”, from the word atomon, literally “uncuttable” or “indivisible” – that is, they cannot be broken down into anything smaller. The universe in fact is said to consist of an infinitely large collection of atoms, which move about in infinite space or “void”.
These atoms, which are too small to be seen by the naked eye, are not only indivisible, but are also eternal, changeless and indestructible. All atoms are made of the same solid matter, and they differ from each other only in size, shape, position and arrangement.
The universe, then, consists of nothing other than these atoms interacting, and striking against one another, in an infinite void. The idea of the “void” was a radical innovation, and it was described simply as nothingness, or what separates one atom from another and therefore what makes motion possible.
This is a universe which is purposeless, mechanistic and deterministic, with no room for divine intervention or design. For the atomists, there is no chance, and whatever happens has to happen. As Leucippus stated: “Nothing happens at random, but everything from reason and by necessity.”
The atomistic philosophy of Leucippus and Democritus was the forerunner in some ways of contemporary particle physics. Like the ancient atomists, physicists now believe that all matter is made up of atoms.
Physicists, however, no longer believe that atoms are indivisible, but regard atoms as made up of a swarm of subatomic particles, including electrons, protons, neutrons, quarks, etc.
But the idea, first presented to the world by Leucippus and Democritus, persists that everything at the micro level is radically different from the way it initially appears to us.
Appearances are one thing, ultimate reality is quite another. We should therefore exercise some caution, if not scepticism, towards appearances.
For as Democritus stated: “In truth we know nothing; for truth is in the depths.”
Dr Nick Trakakis teaches Philosophy and Religious Studies at Monash and Deakin Universities. His most recent book is The End of Philosophy of Religion, published by Continuum in London.