The task originally given to me was to discuss ‘the philosophical basis of medical ethics’. Without wanting to seem ungracious, I want to argue that medical ethics does indeed have a ‘philosophical basis’, although not exclusively or even primarily in moral theory. Medical ethics has a basis in philosophy's long and (mostly) honourable tradition of practical ethics – of attempting to think systematically about the moral problems that people actually face. Whether it also has a basis in moral theory is a more perplexing question.

In an effort to understand the relationship between medical ethics and moral philosophy, I will need to explore several issues. The first problem is to describe the currently dominant model of that relationship, deductivism and to examine its shortcomings. Then I will explore the recent resurgence of attention to the tradition of practical reasoning about cases of conscience commonly called casuistry. ‘Casuistry’, as a concept, has multiple meanings and even more connotations and historical associations. I hope to add some clarity to discussions of casuistry and deductivism by distinguishing between two core meanings of casuistry:

1. (1) as immersion in the particularity of specific cases or problems coupled with the inescapable need for interpretation; and

2. (2) as a claim about the relation between moral judgement and moral theory as sources of moral knowledge.