Online research in philosophy

In this paper I will argue against the Humean theory of motivation, or “conativism” which claims that all actions are ultimately generated by desires. Conativism is supported by (1) a behavioral analysis of desire as a disposition to act in certain ways, and (2) the difference between belief and desire in terms of their different “direction of fi t” with the world. I will show that this behavioral account of desire cannot provide an adequate explanation of action. Mere disposition to act (what I call “wanting”) does not explain why the agent acts; insofar as it explains the action desire is a feeling. I will then argue against the direction of fit argument by showing that beliefs about what we ought to do have both directions of fit—the belief has one direction of fit, and the content of the belief (the ought-clause) has the opposite direction of fit.

In Word and Object, Quine acknowledged the "practical indispensability" in daily life of the intentional idioms of belief and desire but disparaged such talk as an "essentially dramatic idiom" rather than something from which real science could be made in any straightforward way.Endnote 1 Many who agree on little else have agreed with Quine about this, and have gone on to suggest one or another indirect way for science to accommodate folk psychology: Sellars, Davidson, Putnam, Rorty, Stich, the Churchlands, Schiffer and myself, to name a few. This fainthearted consensus is all wrong, according to Fodor, whose new book is a vigorous--even frantic--defense of what he calls Intentional Realism: beliefs and desires are real, causally involved, determinately contentful states. "We have no reason to doubt," Fodor says, "that it is possible to have a scientific psychology that vindicates commonsense belief/desire explanation." (p.16).

Bryne & H´ajek (1997) argue that Lewis’s (1988; 1996) objections to identifying desire with belief do not go through if our notion of desire is ‘causalized’ (characterized by causal, rather than evidential, decision theory). I argue that versions of the argument go through on certain assumptions about the formulation of decision theory. There is one version of causal decision theory where the original arguments cannot be formulated—the ‘imaging’ formulation that Joyce (1999) advocates. But I argue this formulation is independently objectionable. If we want to maintain the desire as belief thesis, there’s no shortcut through causalization.

Rationalizations of deliberation often make reference to two kinds of mental state, which we call belief and desire. It is worth asking whether these kinds are necessarily distinct, or whether it might be possible to construe desire as belief of a certain sort — belief, say, about what would be good. An expected value theory formalizes our notions of belief and desire, treating each as a matter of degree. In this context the thesis that desire is belief might amount to the claim that the degree to which an agent desires any proposition A equals the degree to which the agent believes the proposition that A would be good. We shall write this latter proposition ‘A◦’ (pronounced ‘A halo’). The Desire-as-Belief Thesis states, then, that to each proposition A there corresponds another proposition A◦, where the probability of A◦ equals the expected value of A.

Through the use of such "folk" concepts as belief, desire, intention, and expectation, Daniel Dennett asserts in this first full scale presentation of...