Desire as Belief

Today's post is by Alex Gregory, University of Southampton. In this post, Gregory presents his new book, Desire-as-Belief: A Study of Desire, Motivation, and Rationality, published by OUP in July 2021. You can read some chapter summaries here. And here is a link to chapter 1, which the publisher has kindly agreed to make available for free as a sample. 

What is it to want something? Or, as philosophers might ask, what is a desire? I endorse desire-as-belief, the view that desires are just a special subset of our beliefs. More specifically, I say that to desire P is to believe you have normative reason to bring about P. This view is in one respect highly unorthodox, since many – e.g. Plato, Hume – hold that our desires are really quite different from our beliefs. The view is also unorthodox for suggesting that all our desires can be evaluated for whether they are correct or not. But despite being unorthodox in these ways, I argue that the view is nonetheless attractive. Some orthodoxies should change.

Why endorse the view? One attraction is that desire-as-belief allows us to accept the central and most attractive part of the Humean tradition – the necessity of desire for motivation – without accepting any attendant baggage about the motivational impotence of normative beliefs. According to desire-as-belief, desires are necessary for motivation, but this is wholly consistent with the fact that normative beliefs sometimes motivate us: they are desires, under a different description.

Another attractive feature of the view concerns its implications for rationality. Our desires seem highly relevant for rationality – if we are evaluating whether someone acted rationally, a standard view says to first examine their desires. But why should this be true? Why think of desires as a source of rational pressure rather than as sources of irrationality or else just plain irrelevant? Desire-as-belief supplies a tidy answer: because desires are normative beliefs, and because rationality consists in responding to the normative facts as best you can.

Alex Gregory

I hear you say: “Sure, the view would have some neat features if it were true, but doesn’t it face decisive objections?”. The book shows how the view can overcome a variety of worries that you might have. For illustration, here is a brief account of one small manoeuvre I make. Imagine that Sarah says “There are good reasons for me to give to charity, but I don’t want to”. Sarah’s assertion looks like a potential problem for desire-as-belief, according to which her believing she has reason to give more to charity just is her desiring to do so. But in fact Sarah’s assertion may be consistent with desire-as-belief. By “I don’t want to”, Sarah might mean that she wants not to do so, not that she fails to want to do so (W¬p, not ¬Wp). That is, by “I don’t want to”, Sarah might be reporting her belief that there are some reasons not to give to charity. Then her assertion as a whole reports a conflict between two reasons – two desires – rather than between a present belief and an absent desire. So understood, Sarah’s assertion provides no objection to desire-as-belief.

Of course, much more than this needs to be said to show that desire-as-belief is consistent with the full range of irrationality that we can display, and the full range of common-sense thoughts we have about desire. See the book!