This inaugural lecture considers three main aspects of the relationship between science and morality in Greco-Roman antiquity: first some of the ancient debates on the morality of particular scientific research programmes, especially in connection with the practice of human and animal dissection and vivisection; secondly ancient attempts to secure the autonomy and objectivity of natural scientific inquiry; and thirdly the continuing influence - in certain areas of ancient science - of values, including moral and political values, and of the assumption of the privileged position occupied by human beings in the animal kingdom and the cosmos.