Ralph Barton Perry (July 3, 1876 in Poultney, Vermont – January 22, 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.
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.
He married Rachel Berenson and they lived in Cambridge. Their son was Edward Barton Perry Jr. born at their home 5 Avon Street in Cambridge, 27 Sept. 1906. The son E. B. P. Jr. married in 1932 Harriet Armington Seelye (born Worcester, Massachusetts, 28 May, 1909, daughter of physician and surgeon Dr. Walker Clarke Seelye of Worcester and Annie Ide Barrows Seelye, formerly of Providence, Rhode Island.