In art and architecture functionalism refers to combining aesthetics and efficiency. With intellectual roots in the 18th and 19th centuries, in the 1920s and 30s the Bauhaus movement designed furniture for utility.
In architecture, the idea that function should determine form was exemplified by Le Corbusier’s definition of a house as “a machine for living in.”
In social anthropology and sociology, functionalism (and structural functionalism) envisions society as a self-regulating organism. Social institutions, customs, beliefs and even social deviance all contribute to societal functioning. This approach was especially prominent in the sociological work of Emile Durkheim and Talcott Parsons.
In the Philosophy of Mind functionalism presents a challenge to behaviorism. While strict behaviorism explains the mind by observing external causes and effects, functionalism tries to account for consciousness in terms of all inner and outer causes and effects. Philosophical functionalism considers the possibility, overlooked by behaviorism, of a multiplicity of inner causes and effects existing within the mind. The Internet Encyclopedia of Philosophy simplifies it thus:
Functionalism is a theory about the nature of mental states. According to functionalism, mental states are identified by what they do rather than by what they are made of.¹
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