Born May 18, 1872, in Trelleck, Wales; died Feb. 2, 1970, in Penrhyndeudraeth, Wales. English philosopher, logician, mathematician, sociologist, and public figure.

From 1910 to 1916, Russell was a professor at Cambridge University, from which he had graduated in 1894. He was also a professor at various universities in Great Britain and the United States. In 1908 he became a fellow of the Royal Society. He visited Soviet Russia in 1919.

In his philosophy, Russell underwent a complex evolution, one that he himself characterized as a transition from a Platonic interpretation of Pythagoreanism to Humism. After a shortlived enthusiasm for neo-Hegelianism in its British version, Russell turned to a Platonic variant of idealism and then, under the influence of G. Moore and A. N. Whitehead, to neorealism. Approaching neopositivism in the 1920’s and 1930’s, Russell acknowledged the sole reality of sensory data treated in the spirit of neutral monism, a concept that regarded spirit and matter as logical constructions derived from sensory data. In the 1940’s and 1950’s he turned to the ideas of D. Hume: he admitted the existence of “facts,” which, in contrast to “experience,” were objective, but whose objectivity was based on belief in the existence of the external world.

Russell’s philosophic evolution corresponded to changes in his broad plan to apply the techniques of mathematical logic to theoretical-cognitive studies. In the neorealistic and neopositivistic stages of his evolution, this plan resulted in the dissolution of the theory of knowledge in logical analysis, but subsequently Russell once again acknowledged the independent significance of philosophic problems.

Russell was the creator of the concept of logical atomism and the founder of the philosophy of logical analysis.

A good deal of what Russell wrote treats philosophic questions of mathematics. A paradox of set theory discovered by Russell—called the Russell paradox—led him to construct an original variant of the axiomatic theory of sets and to later attempt reducing mathematics to logic. In Principia Mathematica (1910–13), a three-volume work coauthored with A. N. Whitehead, Russell systematized and developed the deductive-axiomatic construction of logic in an attempt to arrive at a logical substantiation of mathematics. Russell also devised an original theory of descriptions.

In his sociological views, Russell was close to psychologism. He believed that instincts and passions underlie the historical process and human behavior. He asserted that it was impossible to distinguish the main factor among the totality of factors determining historical changes or to establish objective historical laws. In ethics and politics he held to bourgeois liberalism, opposing theories that advocated the absorption of the person by society and the state. His attitude toward Christianity, and in particular toward the hypocrisy of religious ethics, was a negative one; to religious ethics he counterposed the ethics of the science free from the unreasonable.

Characteristic features of Russell’s ethical and sociopolitical positions were an active struggle against fascism, an anti-imperialist orientation, and implacable opposition to war and violent and aggressive methods in international politics. Russell, a founder of the Pugwash movement, stood on the side of progressive social forces favoring the prohibition of nuclear weapons and working for peaceful coexistence. He won the Nobel Prize for literature in 1950.