SummaryDavid Hartley's Observations provides an example from the history of medicine of the bearing of theories of the relationship between body and mind on the problem of morality and free will. Further, Hartley's solution requires a distinction between two understandings of what it means for morality to be rationally grounded. The kind of ethics which can be established for moral agents on the basis of medical knowledge alone (and for which Hartley's “Rule of Life” presents but one historical example) has (...) been termed ‘therapeutic’ It leads to a viewpoint in which it is difficult, if not impossible, to distinguish between the kinds of reasons for supporting morals and the kinds of reasons for supporting good teeth. The kind of ethics which requires additional grounds entering into the motivation of the agent himself has been termed “rational.” This distinction between therapeutic and rational ethics rests on the more basic distinction between general and particular grounds on which to establish a rational system of ethics. As a result, the initial problem of how any account of the body-mind relation might allow for the possibility of ethics leads to the more interesting problem of how a therapeutic interpretation of ethics, which is possible on the grounds of medical knowledge, might be reconciled with a fully rational interpretation of ethics which we require on philosophical grounds. “Medical ethics” has traditionally been viewed as the application of concepts from philosophical ethics to the specific problems presented in medical practice. In consequence of the second problem exposed here, it would be useful to extend the domain of medical ethics from the level of concepts and cases to the level of interpreting the rational grounds for those concepts. Otherwise one may fail to distinguish a medical view of ethics from an ethical view of medicine. (shrink)