Ralph Wedgwood

Is there any distinctive aspect of rationality that deserves the label of “instrumental rationality”? Recently, Joseph Raz (2005) has argued that instrumental rationality is a “myth”. In this essay, I shall give some qualified support to Raz’s position: as I shall argue, many philosophers have indeed been seduced by certain myths about instrumental rationality. Nonetheless, Raz’s conclusion is too strong. Instrumental rationality is not itself a myth: there really is a distinctive aspect of rationality that deserves the label of “instrumental rationality”. In the first two sections of this essay, I shall start by giving a rough intuitive description of the phenomenon that seems to me the best candidate for the label “instrumental rationality”. As we shall see, this rough description gives us reason to reject some of the myths that surround instrumental rationality. Then in the rest of this essay, I shall try to give a more precise general specification of this phenomenon. In Sections 3 and 4, I shall consider what has been said about instrumental rationality by several other philosophers. Identifying what is missing in these other philosophers’ accounts will help me to develop my own positive specification, which I shall present in Sections 5 and 6.

If beliefs are subject to a basic norm of correctness—roughly, to the principle that a belief is correct only if the proposition believed is true—how can this norm guide believers in forming their beliefs? Answer: this norm guides believers indirectly: believers are directly guided by requirements of rationality—which are themselves explained by this norm of correctness. The fundamental connection between rationality and correctness is probabilistic. Incorrectness comes in degrees; for beliefs, these degrees of incorrectness are measured by quadratic scoring rules, such as the so-called Brier score. This account is defended against objections; and its implications for suspension of judgement are explored