William Ritchie Sorley(/ˈsɔːrli/; 4 November 1855 – 28 July 1935), usually cited as W. R. Sorley, was a Scottish philosopher. A Gifford Lecturer, he was one of the British Idealist school of thinkers, with interests in ethics.
William Ritchie Sorley was born in Selkirk, Scotland, the son of Anna Ritchie and William Sorley, a Free Church of Scotland minister. He was educated first at Edinburgh University, where he took a degree in philosophy and mathematics. This was followed by New College, Edinburgh where he studied Theology with the intention of training for the church. He gave this up, and after winning the Shaw Fellowship he spent a year at Trinity College, Cambridge where he took Part II of the Moral Sciences Tripos. He subsequently spent several years at Cambridge where he was lecturer and in 1883 he was elected a Fellow at Trinity.
In 1886, he was appointed to a post at University College, London. After two years he was appointed to a professorship at University College Cardiff, succeeding Andrew Seth as Professor of Logic and Philosophy.
In 1894 he was appointed Professor of Moral Philosophy at the University of Aberdeen, and finally in 1900 he succeeded Henry Sidgwick in the Knightbridge Professorship at the University of Cambridge. He held this post until his retirement in 1933. He was made a Fellow of the British Academy in 1905.