  Of course, there is a sense in which the addict, but not the victim of Tourette’s, is responsive to reasons. But even if we could spell out this distinction in a satisfactory way, we still face the problem of explaining why an agent’s capacity to respond to external reality is relevant to her capacity to govern herself. And there are other problems too. If, for example, nonaction differs from action in virtue of being unresponsive to reasons, then it follows that nonrational animals never really act, or that acting from instinct is acting for reasons. It is not clear what considerations could overcome the implausibility of these implications.