Materialism expresses the view that the only thing that exists is matter; if anything else, such as mental events, exists, then it is reducible to matter.
"Materialism" has also frequently been understood to designate an entire scientific, "rationalistic" world view, particularly by religious thinkers opposed to it and also by Marxists. It typically contrasts both with dualism and with phenomenalism (also known as idealism), and like those theories, has had a long history with many varieties and many distinguished proponents. Materialism has also developed as a pejorative label for a lifestyle pursuing wealth, money, and objects rather than spiritual or mental development.
The definition of "matter" in modern philosophical materialism extends to all scientifically observable entities such as energy, forces, and the curvature of space. In this view, one might speak of the "material world".
Compare also with vitalism.
Ancient Greek philosophers like Parmenides, Epicurus, and even Aristotle prefigure later materialists. Later on, Thomas Hobbes and Pierre Gassendi represent the materialist tradition, in opposition to Rene Descartes' attempts to provide the natural sciences with dualist foundations. Later materialists included Denis Diderot and other French enlightenment thinkers, as well as Ludwig Feuerbach.
Karl Marx and Friedrich Engels, turning the idealist dialectics of Georg Hegel "upside down", provided materialism with a view on processes of quantitative and qualitative change called dialectical materialism, and with a materialist account of the course of history, known as historical materialism.
In recent years, Paul and Patricia Churchland have advocated an extreme form of materialism, eliminativist materialism, which holds that mental phenomena simply do not exist at all -- that talk of the mental reflects a totally spurious "folk psychology" that simply has no basis in fact, something like the way that folk science speaks of demon-caused illness.Varieties of materialism
History of materialism