1. the philosophical position that everything, including mental events, is composed of physical matter and is thus subject to the laws of physics. From this perspective, the mind is considered to exist solely as a set of brain processes (see mind–body problem). Such philosophies can be traced back to ancient times but gained a new impetus from advances in the physical sciences beginning in the 17th century. A particular form of materialism is the dialectical materialism of classical Marxism.

2. the position that the causes of behavior are to be found in the material of the body, particularly the nervous system. It is nearly always associated with hard determinism. See also identity theory; physicalism. Compare idealism; immaterialism.

3. a value system that emphasizes the pursuit and acquisition of material goods and luxuries, typically perceived by the individual as a measure of personal worth and achievement, often at the expense of moral, psychological, and social considerations. —materialist adj., n. —materialistic adj.