n 1: (psychology) a theory that reduces all mental phenomena to simple elements (sensations and feelings) that form complex ideas by association 2: (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" [syn: atomism, atomic theory, atomist theory, atomistic theory] [ant: holism, holistic theory]
nounDate: 1678 1. a doctrine that the physical or physical and mental universe is composed of simple indivisible minute particles 2.individualism 1 • atomistnoun
n. Philos. 1 the theory that all matter consists of tiny individual particles. 2 Psychol. the theory that mental states are made up of elementary units. Derivatives: atomist n. atomistic adj.