Some contemporary theories treat phenomena like weakness of will, compulsion and wantonness as practical failures but not as failures of rationality: say, as failures of autonomy or whatever. Other current theories-the majority see the phenomena as failures of rationality but not as distinctively practical failures. They depict them as always involving a theoretical deficiency: a sort of ignorance, error, inattention or illogic. They represent them as failures which are on a par with breakdowns of theoretical reason; the failures may not (...) have exact theoretical analogues, exact analogues in the breakdown of belief, but they are of essentially the same, cognitive kind. Our approach gives us quite a different view of things. The pathologies which we identify in our taxonomy are distinctively rational failures and distinctively practical failures; they are failures of pure practical reason. (shrink)