Liberalism as a political doctrine is difficult to characterise accurately because of the immense variety within the tradition. Historical changes in the meaning of the term 'liberalism' from the opposite of conservatism to the defence of individualism and free markets make it hard to draw the boundaries of liberalism. The same difficulty applies to the term 'communitarianism'. In a wider sense, it refers to a long tradition of social philosophy from Plato, Aristotle to Hegel and Green; in its contemporary sense, it includes thinkers such as Taylor, Sandel, and Maclntyre. Some of these thinkers accept conservative political theories that defend traditional forms of communities, whereas others embrace radical political views. Most of them do not even classify themselves as communitarians. What unites them is the defence of an essentially social conception of the self, an emphasis on the intrinsic value of community and conceiving freedom as a social achievement that requires specific social institutions and practices. Contemporary communitarians formulate their views in opposition to the individualistic theory of liberalism, and they target in particular the Kantian liberalism of Rawls.