On a standard Aristotelian account, the moral virtues and vices stand in an asymmetric relationship to one another. To help explain this asymmetry, I argue that the vices share significantly less common structure than many think. That there are many ways for agents to get it wrong gives us prima facie reason to think that the vices lack a robust common structure. Further, the most promising candidates for a common structure of the vices fall short. These are that (a) the (...) vices have the common structure of being excesses and deficiencies, (b) the vices result from agents' unreflectively taking their inclinations as their ends, and, relatedly, (c) the vices result from rational corruption. Argument (b), which Terence Irwin and others endorse, is the most promising one, so I focus on it. But it, too, faces weighty objections. I conclude that none of these important arguments establishes the existence of a robust common structure of the moral vices. The great variety of moral vices is a puzzling phenomenon that continues to stand in need of explanation. (shrink)