Meaning : (psychology) a theory that reduces all mental phenomena to simple elements (sensations and feelings) that form complex ideas by association.
Meaning : (chemistry) any theory in which all matter is composed of tiny discrete finite indivisible indestructible particles.
Example :
The ancient Greek philosophers Democritus and Epicurus held atomic theories of the universe.
Synonyms : atomic theory, atomist theory, atomistic theory
The theory that the parts of any whole cannot exist and cannot be understood except in their relation to the whole.
Holism holds that the whole is greater than the sum of its parts.