ATOMISM
atomism, atomic theory, atomist theory, atomistic theory
(noun) (chemistry) any theory in which all matter is composed of tiny discrete finite indivisible indestructible particles; “the ancient Greek philosophers Democritus and Epicurus held atomic theories of the universe”
atomism
(noun) (psychology) a theory that reduces all mental phenomena to simple elements (sensations and feelings) that form complex ideas by association
Source: WordNet® 3.1
Etymology
Noun
atomism (countable and uncountable, plural atomisms)
(philosophy) The ancient Greek theory that all matter is composed of very small indestructible and indivisible particles.
(philosophy) The doctrine that society arises from individuals and that larger structures are unimportant.
Source: Wiktionary
At"om*ism, n. Etym: [Cf. F. atomisme.]
Definition: The doctrine of atoms. See Atomic philosophy, under Atomic.
Source: Webster’s Unabridged Dictionary 1913 Edition