 Value pluralism was indeed at the centre of Berlin’s ethical thought; but there is more to that thought than value pluralism alone. Berlin defined ethical thought as ‘the systematic examination of the relations of human beings to one another, the conceptions, interests and ideals from which human ways of treating one another spring, and the systems of value on which such ends of life are based’. These systems of value are ‘beliefs about how life should be lived, what men and women should be and do’ (1990, 1–2). Just as Berlin’s conception of philosophy was based on a belief about the important role of concepts and categories in people’s lives, his conception of ethics was founded on his belief in the importance of normative or ethical concepts and categories – especially  values.[15]