Ralph Barton Perry (3 July 1876 in Poultney, Vermont - 22 January 1957 in Boston, Massachusetts) was an American philosopher. He was educated at Princeton (B.A., 1896) and at Harvard (M.A., 1897; Ph.D., 1899), where, after teaching philosophy for three years at Williams and Smith colleges, he was instructor (1902-05), assistant professor (1905-13), full professor (1913-30) and Edgar Pierce professor of philosophy (1930-46). He was president of the American Philosophical Association's eastern division in the year 1920-21.[1] A pupil of William James, whose Essays in Radical Empiricism he edited (1912), Perry became one of the leaders of the New Realism movement. Perry argued for a naturalistic theory of value and a New Realist theory of perception and knowledge. He wrote a celebrated biography of William James, which won the 1936 Pulitzer Prize for Biography or Autobiography, and proceeded to a revision of his critical approach to natural knowledge. An active member among a group of American New Realist philosophers, he elaborated around 1910 the program of new realism. However, he soon dissented from moral and spiritual ontology, and turned to a philosophy of disillusionment. Perry was an advocate of a militant democracy: in his words "total but not totalitarian". In 1946-8 he delivered in Glasgow his Gifford Lectures, titled Realms of Value.