Desire as Belief: A Study of Desire, Motivation, and Rationality, by Alex Gregory [Book review]

<p>A traditional Humean view about motivation says that only desires motivate action. This theory meshes with the familiar ‘directions of fit’ metaphor: while beliefs aim to <em>fit the world</em>, desires aim to <em>change it</em>. In this way, desires and beliefs appear to be different types of mental state. But such appearances may be misleading. The central aim of Alex Gregory’s <em>Desire as Belief</em> is to defend the unorthodox thesis that desires (or equivalently, wants) are nothing more than beliefs with a particular normative content, an idea with Aristotelian and Stoic roots (see p. 20). In particular, the proposal is that to desire something amounts to believing that you have a reason to bring it about. It is beliefs of this sort, combined with instrumental beliefs, that explain motivation. Gregory’s book is a consistently impressive defence of what he calls <em>desire-as-belief</em>.</p> <p>Chapter 1 clarifies desire-as-belief by way of an analogy with the mental state of disbelieving. To talk of disbelief, on a straightforward analysis, is to talk jointly of an attitude and a content. That is, disbelieving that p doesn’t seem to refer to a <em>sui generis</em> attitude of disbelieving but rather a belief, namely a belief that not-p. In similar fashion, desire-as-belief says that my desiring that p consists of an attitude – belief – with a certain content – that I have a reason to bring about p. Such first-personal beliefs about reasons are special in that they have <em>both</em> aforementioned directions of fit. They aim to conform to the world insofar as they are correct just in case the belief is true; and they aim to change it insofar as such beliefs dispose the desirer to act according to the relevant reasons.</p>