This lecture insisted upon negative liberty as the political complement to the human capacity for free choice, and made matching metaphysical claims: the nature of being, and especially the conflicts amongst values, were inconsistent with totalitarian claims. Berlin, arguing along this line, provided an account of the perversion of positive liberty into a warrant for such claims, discussed nationalism, and emphasized the value‐pluralism, now linked so frequently with his name.

This item of 1951 gives insight into the development of Berlin's thinking about liberty and related themes. He identified the crucial importance of ‘the Kantian morality’ for his purposes, and contrasted this with consequentialists, Hegel and Marx.