A PRACTICAL REASON IS THE SORT of thing that is supposed to, as it were, "count in favor of" doing something. That some act is, say, morally required, prudentially required, aesthetically beautiful, etc., might be reasons to perform it. Intuitively speaking, if I could save millions from devastating poverty at a tiny cost to myself, I have a reason to do it--a reason that, again intuitively speaking, seems decisive. In this way it is proper to say that practical reasons are normative. Though morality, for instance, may require me to f, I ought to f if and only if I have sufficient practical reason to f.
Though applying this set of conceptual categories to David Hume is certainly anachronistic, I want to inquire into Hume's understanding of practical reasons here. The standard reading of Hume's view holds, among other things, that he is a normative internalist; that, for Hume, legitimate practical reasons must be linked to an agent's set of desires or motivating passions. (2) Though "normative internalism" has a number of different incarnations, normative internalism holds that one's practical reasons are--very roughly--determined by one's desire set. For normative internalism, a purported reason to f is genuine if and only if the agent in question has a desire, the object of which f helps to promote. (3) Because Hume is generally interpreted as holding that an agent's ends must be comprised of her desires, Humean internalism is equivalent to his instrumentalism, the view that one only has practical reason to do what promotes one's ends. (4) Though the internalist, or instrumentalist, reading of Hume is popular, it gives rise to serious puzzles of interpretation. To pick one nearly at random, it appears that, on an internalist reading, Hume has serious difficulties establishing that the so-called "artificial" virtues of justice and promise-keeping are reason-giving, especially when it comes to characters like the sensible knave. (5)
I want to make trouble for this reading of Hume. In particular, I will show that the various passages (especially from the Treatise) that seem to indicate some form of normative internalism are inconclusive at best. Some, relying on these passages, have sought to show that Hume is, rather than an internalist, a "nihilist" or skeptic about practical reasons. (6) Against the internalist and skeptical readings, I argue that there is substantial reason to believe that Hume's corpus is compatible with a more robust account of normativity than internalism allows. If so, we should be hesitant to suggest that Hume cannot solve various puzzles that arise on the assumption of some form of internalism. In particular, I will show that Hume has a genuine response to the sensible knave that establishes the knave's obligation to, among other things, justice.
The organization of this paper runs as follows. In Section 1, I discuss the various reasons one might believe that Hume subscribes to some form of normative internalism. In Section 2, I show how these passages support normative internalism only on dubious interpretive assumptions. Next, I attempt to show that Hume subscribes to two crucial features of the denial of normative internalism. First, Hume attempts to criticize desires and motivations from a point of view that is fully independent of the agent's own subjective motivational set. Second, he believes that this point of view establishes normative obligations on the part of agents. In Section 4, I show how this interpretation can establish a plausible reading of Hume's treatment of the sensible knave in the final section of the Enquiry. In Section 5, I discuss the charity of the resulting view and, in Section 6, I conclude with some very brief thoughts concerning the contemporary relevance of Hume's considered position.
1. Hume's Internalism
Before diving into various passages that seem to point to Hume's normative internalism, it is worthwhile to say a bit about what I mean, and what various interpreters of Hume mean, when referring to "normative internalism. …