The perceived weaknesses of philosophical normative theories as machine ethic candidates have led some philosophers to consider combining them into some kind of a hybrid theory. This chapter develops a philosophical machine ethic which integrates “top-down” normative theories (rule-utilitarianism and prima-facie deontological ethics) and “bottom-up” (case-based reasoning) computational structure. This hybrid ethic is tested in a medical machine whose input-output function is treated as a simulacrum of professional human ethical action in clinical medicine. In six clinical medical simulations run on the proposed hybrid ethic, the output of the machine matched the respective acts of human medical professionals. Thus, the proposed machine ethic emerges as a successful model of medical ethics, and a platform for further developments.