Kantian ethical philosophy has often been criticized for its dependence on an untenable conception of the freedom of the will. Kant is supposed to have asserted that we are morally responsible for all of our actions because we have free will, and that we have free will because we exist in a noumenal world in which we are uninfluenced by the temptations of desire and inclination. If we existed only in the noumenal world, we would invariably act as the categorical imperative requires, but because we are also phenomenal beings we sometimes go wrong. The view so understood gives rise to several problems. First, the claim that purely noumenal persons would act as the categorical imperative requires may be questioned.