Reid's idea is that the only conception we can have of the exertion of power is of that distinctive sort of mental effort in which we engage when we will to do something. Since he holds that the power to act is always accompanied with the power to exert that power, it follows that the only entities that can have power are those who are capable of engaging in the peculiar sort of mental effort with which we are all familiar from our own case. But then it follows that the only entities that can ha