This article examines the moral-theoretic implications of a species of moral incapacity which is frequently acknowledged, but nowhere fully explored, in the extant literature. This is the species ‘moral incapacity of vice,’ comprised of those strict limits to intentional action that manifest a weakness or corruption of moral character. Such incapacities demand closer attention, because they block a prominent line of skepticism about the moral incapacities (skepticism resulting partly from theorists’ heretofore exclusive concern with moral incapacities of virtue). A literary (...) example of moral incapacity of vice is analyzed by means of a Thomistic concept of capital vice. The case blocks moral incapacity skepticism, illustrates that moral incapacities of vice share all of the major criterial (i.e., significant and collectively distinctive) features of moral incapacities of virtue, and brings out the significance of such incapacities for our understanding of character, practical reasoning, and agency. (shrink)