Born in Wales, Bertrand Arthur William Russell, 3d Earl (1872–1970) was a British philosopher, mathematician, and social reformer. The grandson of Lord John Russell, the 1st Earl Russell, he succeeded to the earldom in 1931. While teaching at Cambridge University Russell created his most notable works, Principles of Mathematics (1903) and, with Alfred North Whitehead, Principia Mathematica (3 vol., 1910–13), in which he endeavored to demonstrate how the laws of mathematics could be deduced from the basic axioms of logic. His work influenced 20th-century symbolic logic, set theory in mathematics, and logical positivism, especially in the work of his student Ludwig Wittgenstein. An undogmatic but fervent rationalist, Russell was extremely convinced of the logical independence of individual facts and the dependence of knowledge on the data of original experience. Well known for his social views, he was an energetic pacifist during World War I. In 1927 he and his wife founded the extremely experimental Beacon Hill School. His liberal views on marriage, sex, adultery, and homosexuality made him controversial during most of the 1930s. He deserted pacifism during World War II in the face of the Nazi menace, but returned to it after the war, becoming a leader in the “ban the bomb” movement to stop the manufacture of nuclear weapons. In the 1960s he and Jean-Paul Sartre organized European opposition to U.S. participation in the Vietnam War. Russell's radicalism kept him from a conventional academic career, and he sustained himself primarily by his writings, many of them extensively read, e.g., Marriage and Morals (1929), A History of Western Philosophy (1945), and his autobiography (3 vol., 1967–69). In 1950 he was awarded the Nobel Prize in literature.