This concluding chapter of FREEDOM AND MORAL SENTIMENT (OUP 1995) provides a qualified defense of Hume's naturalistic approach to the problem of free will and moral responsibility. A particularly important theme is the contrast between Hume's naturalistic approach and the “rationalistic” approach associated with classical compatibilism. Whereas the rationalistic approach proceeds as an a priori, conceptual investigation into the nature and conditions of moral responsibility, the naturalistic approach is committed to an empirically oriented (i.e., psychologically informed) examination of these issues – giving particular prominence to the role of moral sentiment in understanding moral life and the place of justificatory issues as they arise within it. Whereas the rationalistic approach leads us into intractable difficulties and moral skepticism, the naturalistic approach makes real progress on this subject. On a more critical note, however, I also argue that, despite its strengths, Hume's theory of moral responsibility has significant weaknesses in the areas of moral virtue, moral capacity, and moral freedom.