Some philosophers hold that „ought‟ is ambiguous between a sense expressing a propositional operator and a sense expressing a relation between an agent and an action. We defend the opposing view that „ought‟ always expresses a propositional operator against Mark Schroeder‟s recent objections that it cannot adequately accommodate an ambiguity in „ought‟ sentences between evaluative and deliberative readings, predicting readings of sentences that are not actually available. We show how adopting an independently well-motivated contrastivist semantics for „ought‟, according to which (...) „ought‟ is always relativized to a contrast set of relevant alternatives, enables us to explain the evaluative-deliberative ambiguity and why the availability of these readings depends on sentential grammar. (shrink)

Some intuitive normative principles raise vexing 'detaching problems' by their failure to license modus ponens. I examine three such principles (a self-reliance principle and two different instrumental principles) and recent stategies employed to resolve their detaching problems. I show that solving these problems necessitates postulating an indefinitely large number of senses for 'ought'. The semantics for 'ought' that is standard in linguistics offers a unifying strategy for solving these problems, but I argue that an alternative approach combining an end-relational theory (...) of normativity with a comparative probabilistic semantics for 'ought' provides a more satisfactory solution. (shrink)