Philosophical theories about the nature of belief can be roughly classified into two groups: those that treat beliefs as occurrent mental states or episodes and those that treat beliefs as dispositions. David Hume's A Treatise of Human Nature seems to contain a classic example of an occurrence theory of belief. Hume defines 'belief' as 'a lively idea related to or associated with a present impression' (Treatise 18.104.22.168 96).1 This definition suggests that believing is an occurrent mental state, such as judging, or thinking about something in a particular manner. However, at the same time, a number of Hume's readers claim to find elements in his writings that are suggestive of a dispositional account of belief.2 Moreover, these elements are sometimes taken as signs of the inadequacy [End Page 155] of Hume's account of belief and his dissatisfaction with it.3 If Hume is not, in fact, wholeheartedly committed to a thoroughgoing occurrence theory of belief, one wonders just who is.
My aim in this paper is to argue that Hume does hold an occurrence theory of belief, that he has deep-seated reasons for doing so, and that this theory of belief has greater explanatory power than its critics generally allow. I contend in particular that beliefs play an explanatory role in Hume's Science of Man that could not be played by dispositions, but requires that beliefs be introspectible occurrent mental states. Attention to the role of belief in explaining our actions, thoughts, emotional responses, and reasoning reveals that Hume is committed to treating beliefs as occurrent states. I begin the paper by considering some of the elements in the Treatise that seem suggestive of a dispositional theory of belief. In particular, I consider Louis Loeb's dispositionalist interpretation. Loeb's account is striking because he does not merely claim to find elements in the Treatise that are suggestive of a dispositional theory of belief; he also argues that Hume is fundamentally, albeit implicitly, committed to a dispositional theory of belief, and he develops an interpretation of Hume's views about the justification of belief that is based on taking beliefs to be steady dispositions.4 Loeb claims that Hume's apparent commitment to an occurrence theory of belief obscures the development of a philosophically preferable dispositional account of belief, and he claims that taking beliefs to be dispositions is necessary to make sense of Hume's broader philosophical project, in particular Hume's views about the justification of belief.
Loeb concedes that Hume's official, explicit account of belief is an occurrence theory; the disagreement between Loeb's interpretation and the one I will defend concerns the strength of Hume's commitment to this official theory. To settle such a disagreement it does not suffice to cite textual evidence that shows that Hume explicitly treats beliefs as occurrent states. I propose that focusing on the explanatory role that beliefs play in the Treatise helps to reveal the character of Hume's central commitments. I will argue that, because Hume's explanation of the influence of belief requires that beliefs be occurrent states, Hume's official occurrence theory of belief is also the central and fundamental theory of belief found in the Treatise.
One can distinguish two explanatory projects in the Treatise. The first is to explain how we form beliefs, including how we form beliefs about [End Page 156] the unobserved, beliefs about causation, and beliefs about enduring objects. The second is to explain how believing influences us—how beliefs influence our thoughts, other beliefs, passions, and behavior. While the bulk of Book I, Part 3 is concerned with explaining how beliefforming mechanisms operate, the section entitled 'Of the influence of belief' and passages in the Appendix, in particular, reveal a concern with explaining why beliefs influence us in the way they do. Moreover, one of the objectives of Books II and III of the Treatise is to explain the role of belief in influencing our passions, motivating actions, and in forming moral judgments.5 By 'the influence of belief,' I mean the psychological and behavioral changes...