naturalism, in philosophy, a position that attempts to explain all phenomena and account for all values by means of strictly natural (as opposed to supernatural) categories. The particular meaning of naturalism varies with what is opposed to it. It is usually considered the opposite of idealism, is sometimes equated with empiricism or materialism, and is not easily distinguished from positivism. Naturalism limits itself to a search for causes and takes little account of reasons. Naturalism in the broad sense has been maintained in diverse forms by Aristotle, the Cynics, the Stoics, Giordano Bruno, Spinoza, Thomas Hobbes, Auguste Comte, Friedrich Nietzsche, Karl Marx, William James, John Dewey, and Alfred North Whitehead, philosophers who differ widely on specific questions. Some, like Comte and Nietzsche, were professed atheists, while others accepted a god in pantheistic terms. Aristotle, James, and Dewey all attempted to explain phenomena in terms of biological processes of perception; Spinoza and the idealists tended to emphasize metaphysics; later thinkers of all schools have placed emphasis on unifying the scientific viewpoint with an all-encompassing reality. This amalgamation of science and an overall explanation of the universe in naturalistic terms is the source of much of contemporary philosophic thought.
See J. M. Ferreira, Skepticism and Reasonable Doubt (1987); P. F. Strawson, Skepticism and Naturalism: Some Varieties (1987).