Atomism (Greek atomon, "uncuttable") is the philosophic and scientific theory that reality is composed of indivisible elementary parts called atoms. A theory of physical atoms was first advanced by Leucippus and Democritus; later, it was developed by Lucretius. A more complex version of the theory is held by natural scientists today, although at present it is not clear which particles are the most fundamental units of matter. Atomism also denotes theories that may be psychological (the "simple ideas" of John Locke and David Hume) or linguistic (as in the elementary propositions of logical atomism).
Robert S. Brumbaugh
Last modified on: Friday, October 17, 1997.