The concept of identity has changed considerably over the past half century as philosophical theories concerning the subject have been transformed by positivism, post-war experience, the collapse of Empire, the rise of multiculturalism, feminism, and the post-structuralist and postcolonial deconstruction of the subject. Emmanuel Levinas is one voice in a large company of theorists who have criticised the claims of Enlightenment reason and the centrality of the Cartesian subject and the category of identity; his critique of Western philosophy has been hugely influential across a broad range of disciplines. In particular, Levinas' description of the self in relation to the Other, a relationship he describes as essentially "ethical', decentres the Cartesian subject and opens up a positive account of difference that places ethics at the heart of identity and alterity. His thought is also evocative in an extra-philosophical sense as the reintroduction of Jewish concepts and narrative into philosophy disrupts the univocality of a tradition that has worked hard to eradicate its theological inheritance.