3rd Earl Russell (1872–1970), British philosopher, mathematician, and social reformer; full name Bertrand Arthur William Russell. In Principia Mathematica (1910–13) he and A. N. Whitehead attempted to express all of mathematics in formal logic terms. He expounded logical atomism in Our Knowledge of the External World (1914) and neutral monism in The Analysis of Mind (1921). A conscientious objector during the First World War, he also campaigned for women's suffrage and against nuclear arms. Nobel Prize for Literature (1950).