  Interpreters disagree as to whether Hume is an instrumentalist or a skeptic about practical reason. Either way, Hume denies that reason can evaluate the ends people set themselves; only passions can select ends, and reason cannot evaluate passions.  Instrumentalists understand the claim that reason is the slave of the passions to allow that reason not only discovers the causally efficacious means to our ends (a task of theoretical causal reasoning) but also requires us to take them. If Hume regards the failure to take the known means to one’s end as contrary to reason, then on Hume’s view reason has a genuinely practical aspect: it can classify some actions as unreasonable. Skeptical interpreters read Hume, instead, as denying that reason imposes any requirements on action, even the requirement to take the known, available means to one’s end. They point to the list of extreme actions that are not contrary to reason (such as preferring one’s own lesser good to one’s greater), and to the Representation Argument, which denies that any passions, volitions, or actions are of such a nature as to be contrary to reason. Hume never says explicitly that failing to take the known means to one’s end is either contrary to reason or not contrary to reason (it is not one of the extreme cases in his list). The classificatory point in the Representation Argument favors the reading of Hume as a skeptic about practical reason; but that argument is absent from the moral Enquiry.