One ought too many

ABSTRACT: 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 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. Normative branches of philosophy take special interest in claims expressed by sentences of the form 'S ought to ', where S is some agent and -ing is some action (broadly conceived). We'll call sentences satisfying this description agential. These claims raise many important philosophical issues, such as: Which ones are true? What makes them true? How can we know if they are true? What follows from them? Some philosophers have hoped that light would be cast on these issues if we could get clearer on the exact meaning of this word 'ought'. Once we start looking to language for philosophical clues we should notice that the word 'ought' is also employed in different kinds of sentence. It appears in normative sentences with different grammatical forms, like 'It ought to be that Charlie was born a girl', and 'There ought to be less suffering in the world'. For convenience we'll call sentences like these nonagential. 1 (It also has a non-normative epistemic use meaning We owe this play on Bernard Williams' phrase to Jake Ross; Terence Cuneo has previously used it with a different signification as a section title of his book The Normative Web (Oxford University Press, 2007 According to this Ambiguity Thesis 'ought' is semantically and logically ambiguous, so it is a mistake to try to draw philosophical lessons about the agential 'ought' claims of interest to normative philosophy from the other uses of the word. In this paper we defend the Uniformity Thesis against the central objection that it cannot account for all the linguistic data from ordinary usage of 'ought'. Versions of this objection have been raised by a number of philosophers including Gilbert Harman, Peter Geach, Anthony Price, and most recently and rigorously Mark Schroeder. After clarifying which ambiguity is at issue and explaining the Overgeneration problem it faces, we introduce a contrastivist semantics for 'ought' and show how it provides resources for accommodating and explaining the problematic data without attributing any semantic or logical ambiguity to the word 'ought'. Officially we remain neutral about whether contrastivism and the 2 The seminal texts in linguistics are Anselm)