Weakness of Will

My chief aim is to explain how someone can act freely against her own best judgment. But I also have a second aim: to defend a conception of practical rationality according to which someone cannot do something freely if she believes it would be better to do something else. These aims may appear incompatible. But I argue that practical reason has the capacity to undermine itself in such a way that it produces reasons for behaving irrationally. Weakness of will is possible because it is possible to conclude that one has sufficient reason to reject the verdicts of one's own reason.