Mannheim Karl (1893–1947), Hungarian-born German social scientist best known for his sociology of knowledge. Born in Budapest, where he took a university degree in philosophy, he settled in Heidelberg in 1919 as a private scholar until his call to Frankfurt as professor of sociology in 1928. Suspended as a Jew and as foreign-born by the Nazis in 1933, he accepted an invitation from the London School of Economics, where he was a lecturer for a decade. In 1943, Mannheim became the first professor of sociology of education at the University of London, a position he held until his death. Trained in the Hegelian tradition, Mannheim defies easy categorization: his mature politics became those of a liberal committed to social planning; with his many studies in the sociology of culture, of political ideologies, of social organization, of education, and of knowledge, among others, he founded several subdisciplines in sociology and political science. While his Man and Society in an Age of Reconstruction (1940) expressed his own commitment to social planning, his most famous work, Ideology and Utopia (original German edition, 1929; revised English edition, 1936), established sociology of knowledge as a scientific enterprise and simultaneously cast doubt on the possibility of the very scientific knowledge on which social planning was to proceed. As developed by Mannheim, sociology of knowledge attempts to find the social causes of beliefs as contrasted with the reasons people have for them. Mannheim seemed to believe that this investigation both presupposes and demonstrates the impossibility of ‘objective’ knowledge of society, a theme that relates sociology of knowledge to its roots in German philosophy and social theory (especially Marxism) and earlier in the thought of the idéologues of the immediate post–French Revolution decades. L.A. Mansel, Henry Longueville (1820–71), British philosopher and clergyman, a prominent defender of Scottish common sense philosophy. Mansel was a professor of philosophy and ecclesiastical history at Oxford, and the dean of St. Paul’s Cathedral. Much of his philosophy was derived from Kant as interpreted by Hamilton. In Prolegomena Logica (1851) he defined logic as the science of the laws of thought, while in Metaphysics (1860) he argued that human faculties are not suited to know the ultimate nature of things. He drew the religious implications of these views in his most influential work, The Limits of Religious Thought (1858), by arguing that God is rationally inconceivable and that the only available conception of God is an analogical one derived from revelation. From this he concluded that religious dogma is immune from rational criticism. In the ensuing controversy Mansel was criticized by Spenser, Thomas Henry Huxley (1825–95), and J. S. Mill. J.W.A.