Stephen Sir Leslie (1832–1904), English literary critic, editor, intellectual historian, and philosopher. He was the first chief editor of the great Dictionary of National Biography, writing hundreds of the entries himself. Brought up in an intensely religious household, he lost his faith and spent much of his time trying to construct a moral and intellectual outlook to replace it. His main works in intellectual history, the two-volume History of English Thought in the Eighteenth Century (1876) and the three-volume English Utilitarians (1900), were undertaken as part of this project. So was his one purely philosophical work, the Science of Ethics (1882), in which he tried to develop an evolutionary theory of morality. Stephen was impatient of philosophical technicalities. Hence his treatise on ethics does very little to resolve the problems – some of them pointed out to him by his friend Henry Sidgwick – with evolutionary ethics, and does not get beyond the several other works on the subject published during this period. His histories of thought are sometimes superficial, and their focus of interest is not ours; but they are still useful because of their scope and the massive scholarship they put to use. See also DARWINIS. J.B.S.