The chapter explores in the nature of the act of the will Kant analyses in Groundwork I and II. I argue that Kant provides us with a metaphysical – and not phenomenological – analysis of what it means to have a will. The phenomenological analysis is subject to skeptical challenges. His argument is based on what follows when we take ourselves as having a will, something that we do every time we act. This analysis reveals that the act of willing immediately implies a subjection to the moral law. This act of the will is identical to the fact of reason with which Kant begins his second Critique. I show this through a closer look at what follows when we take the will as negatively free, that is, as not determined in the order of causes. I argue that Kant held that when we examine the essence of the will, it follows that any act of willing that is negatively free must also have a law of its activity, one supplied by reason, for the idea of an undetermined will contains a contradiction (6:35). Hence any act of the will must embody both negative and positive freedom. This means further that Kant is an internalist about reasons for moral action.