Monism

Monism (Greek, monos, “single”), in philosophy, doctrine that ultimate reality is composed entirely of one substance. Monism is thus opposed to both dualism and pluralism. Three basic types of monism are recognized: materialistic monism, idealistic monism, and the mind-stuff theory. According to the first doctrine, everything in the universe, including mental phenomena, is reduced to the one category of matter, as in materialism. In the second doctrine, matter is regarded as a form of manifestation of the mind; and in the third doctrine, matter and mind are considered to be merely aspects of each other. Although monistic philosophies date from ancient Greece, the term monism is comparatively recent. It was first used by the 18th-century German philosopher Christian Wolff to designate types of philosophical thought in which an attempt was made to eliminate the dichotomy of body and mind.

Although he was not known by the term, the 17th-century Dutch philosopher Baruch Spinoza was one of the most influential monists. He taught that both material and spiritual phenomena are attributes of one underlying substance. His doctrine strongly anticipated the mind-stuff theory.