Let us refer to the claim that the good is the object of desire in a sense analogous to how the true is the object of belief as the Broadly Anscombean View. One way of unpacking the Broadly Anscombean view is in terms of the Desire-as-Belief Thesis. In his paper, “Belief, Desire, and Revision”, John Collins defines the Desire-as-Belief Thesis as “the thesis that desire is a particular kind of belief—that to desire A is simply to believe that A would be good."
We may distinguish between weak and strong versions of the Desire-as-Belief Thesis; the claim that some desires are beliefs and the claim that all desires are beliefs, respectively. But this distinction, while significant in its own right, will have little bearing on the present discussion. This is because we are only concerned with the Desire-as-Belief Thesis as a means of unpacking the Broadly Anscombean View; namely, the claim that the good is the object of desire. When we unpack the Broadly Anscombean View in terms of the Desire-as-Belief Thesis, we arrive at the claim that desiring to φ is identical to the belief that φ is good. Now, according to the weak version of the Desire-as-Belief Thesis, only some desires to φ are identical to the belief that φ is good. However, on those occasions in which the desire to φ is not identical to the belief that φ is good, the desire in question does not have the good as its object. Therefore, the Broadly Anscombean View does not apply to such desires. Hence, insofar as we are interested in the Desire-as-Belief Thesis as a means of unpacking the Broadly Anscombean View, we are only concerned with those cases in which a desire may be said to be identical to a belief. Consequently, the distinction between the weak and strong versions of the Desire-as-Belief Thesis is superflous for our present purposes.
In his paper, “Defending Desire-as-Belief”, Huw Price highlights two motivations for the desire-as-belief thesis; a rejection of the Humean theory of desire and a defence of anti-emotivism in moral discourse. He writes:
In modern terminology the Humean view is thus that action is a joint product of an agent's beliefs and desires; and that these are distinct kinds of mental states, desires being distinguished from beliefs in virtue of their motivational role .... In recent years, however, several philosophers have questioned the Humean orthodoxy. They suggest that certain beliefs might be intrisically motivational—in effect, in other words, that some or all desires might themselves be beliefs .... An attractive feature of the suggestion that (some) desires might be beliefs has been its evident potential to undermine emotivist accounts of moral discourse (and so to enable ethical statements to be brought within the scope of a truth-conditional general semantics).
According to Price, the Humean view amounts to the thesis that desires are intrinsically motivational while beliefs are not. Moreover, Price construes emotivist accounts of moral discourse as entailing the denial of the claim that ethical statements display a truth-conditional semantics. I will refer to the rejection of the Humean view as Anti-Humeanism, and the rejection of the emotivism as Anti-Emotivism.
Although, in the passage just cited, Price associates the Desire-as-Belief Thesis with Anti-Humeanism and Anti-Emotivism, it is worth emphasising that the denial of the Desire-as-Belief Thesis is consistent with both. It is common ground between the Humean and the Anti-Humean that desires are intrinsically motivating. However, the Humean denies, and the Anti-Humean affirms, that some beliefs are also intrinsically motivating. But one may consitently subscribe to the claim that some beliefs are intrinsically motivating and yet deny that desires are beliefs. For example, suppose one held that being intrinsically motivational is a necessary but insufficient condition for a psychological state to be a desire. Then one may also consistently hold that desires are distinct psychological states from beliefs (thereby denying the Desire-as-Belief Thesis) and that some beliefs are intrinsically motivational (thereby affirming non-Humeanism).
Moreover, if we identify the content of moral discourse with the content of an intrinsically motivating belief (rather than with the content of a desire), then we may consistently hold that moral discourse displays a truth-conditional semantics and that the content of desire does not. One only needs to add the further assumption that the content of an intrinsically motivating belief displays a truth-conditional semantics. Hence, if we reject the Desire-as-Belief Thesis, it does not follow from this rejection that either Anti-Humeanism or Anti-Emotivism is false.
The preceding observations draw attention to an important feature of Price's account. Price associates the claim that “certain beliefs might be intrinsically motivational” with the claim that “some or all desires might themesleves be beliefs”; either equating the two claims or taking the second to be entailed by the first. However, the equivalence or entailment only holds if we assume that being motivational is a sufficient condition for a psychological state to be a desire. In brief, Price assumes that only desires are intrinsically motivational. However, it seems like both the Humean and the Anti-Humean alike is well within her rights in rejecting this assumption. For example, both the Humean and the Anti-Humean may hold that certain emotions, like love and hatred, are intrinsically motivational. However, it is not immediately clear, nor is it a fundamental assumption of either Humeanism or Anti-Humeanism, that love and hate are desires. In fact, both the Humean and Anti-Humean is free to deny that emotions, like love or hate, are (typically) propositional attitudes.
While I do not wish to either endorse or impugn such a position, I do wish to stress that it is not inconsistent with either Humeanism or Anti-Humeanism. The upshot is that both the Humean and Anti-Humean may reject the claim that only desires are intrinsically motivating. If this suggestion is right, then it is best to see Humeanism as being committed, not to the thesis that desires are the only psychological states that are intrinsically motivating, but rather to the claim that beliefs are not among those psychological states that are. The Anti-Humean, by contrast, wants to insist that at least some beliefs (perhaps, beliefs about the good or about what one should do) are included among the set of psychological states that are intrinsically motivationg. But once it is acknowledge that the set of intrinsically motivating psychological states is not limited to desires, then (as far as Anti-Humeanism is concerned) there is no need to insist that desires are beliefs.