A second kind of formal rationality, complementary to the maximizing expected utility in Chapter 1, is logical inference. In much of moral philosophy and in standard bioethics decision making is applied ethics. Moral theories are taken to be comprised of principles that are applied to the facts of cases to deduce conclusions about what ought to be done. The canonical depiction of bioethics, for instance, consists of the four principles of non-maleficence, beneficence, autonomy, and justice. The real examples in this chapter expose the many failings of that applied ethics. Most of the cases are about when to die and how to die, but the term ‘euthanasia’ is indeterminate. The crucial notion of ‘autonomy’ also is indeterminate. Both need to be clarified and specified. But how is this to be done? Similarly, when principles and rules conflict, as they often do, how is the one that prevails to be determined? There are no higher principles or rules that can be applied to get the right answer in any of these cases. More broadly, what makes a problem a moral problem, and what does being a moral problem mean? These issues require non-formal rational deliberation, not the formal rationality of deduction.