naturalism, in art, a tendency toward strict adherence to the physical appearance of nature and rejection of ideal forms. Artists as diverse as Velázquez, J. F. Millet, and Monet, have followed naturalistic principles.

naturalism, in literature, an approach that proceeds from an analysis of reality in terms of natural forces, e.g., heredity, environment, physical drives. The chief literary theorist on naturalism was Émile Zola, who said in his essay Le Roman expérimental (1880) that the novelist should be like the scientist, examining dispassionately various phenomena in life and drawing indisputable conclusions. The naturalists tended to concern themselves with the harsh, often sordid, aspects of life. Notable naturalists include the Goncourt brothers, J. K. Huysmans, Maupassant, the English authors George Moore and George Gissing, and the American writers Theodore Dreiser, Frank Norris, Stephen Crane, James T. Farrell, and James Jones. In the drama, naturalism developed in the late 19th cent. By stressing photographic detail in scene design, costume, and acting technique, it attempted to abolish the artificial theatricality prominent in 19th-century theater. The movement was most closely associated with the Théâtre Libre (founded 1887) of André Antoine, with the Freie Bühne (founded 1889) of Otto Brahm, and with the Moscow Art Theatre (founded 1898) under the direction of Stanislavsky. Notable naturalistic dramatists include Becque, Brieux, Hauptmann, and Gorky.

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.

In philosophy, the theory that affirms that all beings and events in the universe are natural and therefore can be fully known by the methods of scientific investigation. Though naturalism has often been equated with materialism, it is much broader in scope. Strictly speaking, naturalism has no ontological bias toward any particular set of categories of reality: dualism and monism, atheism and theism, idealism and materialism are all compatible with it. Naturalism was most influential in the 1930s and '40s, chiefly in the U.S. among philosophers such as F.J.E. Woodbridge (1867–1940), Morris R. Cohen (1880–1947), John Dewey, Ernest Nagel (1901–85), Sidney Hook (1902–89), and W.V.O. Quine.

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