Various challenges could be raised against Hume’s rather narrow  conception of reason.  But our primary interest here is in whether Hume  can provide us with a plausible account of instrumental rationality.  On Hume’s view, our intentions are subject to rational criticism when,  and only when, they are based on false beliefs (and, again, it’s the  belief that’s to blame, strictly speaking).  As an account of  instrumental rationality, Hume’s view would face two serious objections.