Moral philosophers widely believe that it is a part of the MEANING of 'ought' statements that they imply 'can' statements. To this thesis I offer three challenges, and then I conclude on a broader methodological note. (1) Epistemological Modal Argument: for all we know, determinism is true; determinism contradicts “ought implies can”; therefore we don’t know that 'ought' implies 'can'. (2) Metaphysical Modal Argument: determinism is conceptually possible; determinism contradicts “ought implies can”; therefore “ought implies can” is not an analytic (...) truth. (3) Semantic Argument: “You ought to X” is equivalent to “Do X!”; but “Do X!” does not entail that you can X, according to leading analyses of the imperative. (4) My two modal arguments are epistemologically significant, for they illustrate a general method for refuting a whole class of argument. (shrink)

There has been much debate recently over the possibility of moral dilemmas, where a moral dilemma is defined as a situation in which an agent morally ought to do each of two incompatible actions. An assumption that seems to be shared by both opponents and proponents of moral dilemmas is that their respective positions can be established without appeal to substantive moral considerations, and hence one or the other position can be imposed as a neutral methodological constraint on the construction (...) of a moral theory. I call this assumption the priority thesis. ;This dissertation examines the priority thesis with regard to a particular type of moral dilemma, namely, a nofault dilemma, which is defined as a moral dilemma which is not the result of any agent's past wrongdoing. The question is whether the possibility or impossibility of a no-fault dilemma can be established independently of making substantive moral claims. I argue that neither claim about nofault dilemmas can be defended without appeal to substantive moral considerations, and conclude that the priority thesis should be rejected. Independently of making substantive moral assumptions, there is no basis for the claim that either position should be imposed as a methodological constraint on the construction of a moral theory. (shrink)