The main contemporary motivation for the Guise of the Good Theory of Desires--namely, the claim that desires aim at the good (henceforth, GG theory)--comes from Anscombe, who claims that wanting aims at the good in the same sense that judgement aims at truth. Anscombe's claim has lead many GG theorists to draw an analogy between desire and belief. However, I believe that this is mistake. When Anscombe says that wanting aims at the good, she actually has something quite different from our ordinary conception of desires in mind:
'Wanting' may of course be applied to the prick of desire at the thought or sight of an object, even though a man then does nothing towards getting the object. . . . The wanting that interests us, however, is neither wishing nor hoping nor feeling nor desire, and cannot be said to exist in a man who does nothing towards getting what he wants. (Anscombe , Intention. p. 67-68.)
The above passage suggests that Anscombe's notion of wanting is more like an intention than a desire; it entails taking steps towards getting the object wanted. If this is right, then the Anscombean thesis is most aptly interpreted as the claim that intentions aim at the good in the same way that beliefs aim at truth. On this reading, the appropriate analogy is not one between belief and desire, but between belief and intention.
The claim that intentions aim at the good in the same sense that belief aims at the true gives rise to the following question. In what sense does belief aim at the true? We may distinguish between psychological, metaphysical and normative readings of the claim that belief aims at the true. According to psychological reading, beliefs may be said to aim at the true because agents are motivated to form beliefs by a desire for truth. The psychological reading was famously denied by Charles Pierce, who insisted that our motivation for forming beliefs is a desire to alleviate the discomfort caused by doubt. Even if one does not buy into Pierce's positive claim, it seems undeniable that we are often motivated to form beliefs by considerations other than truth. Pride, fear, comfort, and consistency are just a few of the many possible motivations an agent may have for adopting a particular belief. Consequently, the claim that truth is the psychological aim of belief seems implausible.
According to the metaphysical reading, truth is what makes belief the kind of psychological state it is. On this view, if the proposition that constitutes the intentional object of a putative belief turns out to be false, then the attitude in question is not a belief. It should be immediately clear that when we say belief aims at the true, we do not mean that truth is the metaphysical aim of belief; to wit, that a belief only counts as such if the proposition believed is true. Such a view would have the implausible consequence that there are no false beliefs. Moreover, it threatens to collapse the distinction between belief and knowledge, since the latter does seem to have truth as its metaphysical aim; to wit, knowing that p counts as such only if p is true. Consequently, the claim that truth is metaphysical aim of belief also seems implausible.
I believe that the claim that belief aims after truth is best understood in normative terms. According to the normative reading, the belief that p is in some sense incorrect if p is false. Unlike the metaphysical reading, the normative reading does not entail that a belief only counts as such if the believed proposition is true. Thus, the normative reading makes room for the possibility of false beliefs. Moreover, unlike the psychological reading, the normative reading does not entail that we are always motivated to form beliefs by a desire for truth. Consequently, the claim that truth is normative aim of belief is more plausible, and does a better job of capturing what we mean when we say that belief aims after truth, than the psychological and metaphysical readings. Given the normative reading of the claim that belief aims at the true, the claim that intentions aim at the good in the same sense that belief aims at the true entails that the intention to φ is incorrect if φ is not good.
Having said what it means to say that intentions aim at the good, we may now ask why intentions may be said to aim at the good in aforementioned sense. One proposal is to say that the good is the normative aim of intention because an intention to φ is justified if and only if φ is good. However, this is not plausible. First, the intention of φ may be justified if the agent has a justified, but false, belief that φ is good. For example, suppose Mary has the justified belief that it would be good to give to a charity X, when in fact the charity X is a scam and it would in fact not be good to give to X. Quite plausibly, it may still be justified for Mary to adopt the intention to give to charity X, given her justified belief that it would be good to do so. Second, the intention to φ is not justified if the agent has the justified, but false, belief that φ is not good. For example, suppose Bob has the justified belief that allowing his company to dump industrial waste in a river would harm the environment, when in fact the waste in question may actually be beneficial to the environment. Quite plausibly, it may be unjustified for Bob to adopt the intention to allow his company to dump the industrial waste, given his justified belief that doing so would be harmful.
An alternative proposal, the one I wish to endorse, is to say that intentions have the normative aim of the good because intending to φ entails being committed to the goodness of φ. On this view, the claim that a psychological state or speech-act has a particular normative aim is not a claim about when an agent is justified in adopting that psychological state or engaging in that speech-act. Rather, it is a claim about the types of normative commitments an agent takes upon herself by adopting a particular attitude, and the type of rational criticism said commitment entails. Thus, if an agent adopts an intention to φ, and subsequently learns that φ is not good, then that agent is normatively committed to giving up the intention to φ and is rationally criticisable if she fails to do so. In this regard, the normative aim of intention is perfectly analogous to normative aim of belief. Truth is the normative aim of belief because believing that p entails being committed to truth of p. If an agent adopts the belief that p, and subsequently learns that p is not true, then that agent is normatively committed to giving up her belief that p and is rationally criticisable if she fails to do so.
The preceding discussion offers us an analysis of what it means for intentions to aim at the good. But what can we say about the relationship between desires and the good? In answering this question, I exploit an analogy between desire and perceptual experience. To this end, we may say that desires aim at the good in the same sense that perceptual experience aims at the true. However, it is not plausible that perceptual experiences aim at the true in the same way that belief aims at the true. Recall, we unpacked the claim that belief aims at the true in terms of the claim that believing that p entails that one is committed to the truth of p. However, perceiving that p does not entail that one is committed to the truth of p. Moreover, if one perceives that p, one is not in a position to alter one’s perceptual experience if it turns out that p is false. Thus, it would not do to say that perceptual experiences aim at the true in the same sense that belief does.
Instead, I propose that we see perceptual experiences as aiming at the true in a derivative sense. To wit, we may say that a perceptual experience is correct just in case it would yield a correct belief if it were assented to. Given that the belief that p is correct only if p is true, it follows that a perceptual experience that p is correct (in a derivative sense) only if p is true. Analogously, desires may be said to aim at the good in a derivative sense. To wit, we may say that a desire is correct (in a derivative sense) just in case it would yield a correct intention if it were assented to. Since the intention to φ is correct just in case φ is good, it follows that the desire to φ is correct (in a derivative sense) just in case φ is good.