Kant’s thesis that there is in human nature an innate, universal, inextirpable, and radical propensity to evil belongs to his attempt to choose fragments of (Christian) revelation and see if they cannot be seen to lead back to the religion of pure reason. Though Kant regards this thesis as unproven, he offers it as an interpretation of the Christian doctrine of original sin that can be used in moral discipline, though not in moral dogmatics. To understand Kant’s concept of evil, we must understand his concept of freedom and disentangle it from incomprehensible metaphysical speculations with which it has often been associated in the literature. Kant’s concept of moral evil is extremely abstract, consisting in the choice of some nonmoral incentive over the moral incentive. Evil can never be made entirely intelligible because evil is action, hence done for reasons, but there can never be a sufficient or decisive reason for doing it because the moral incentive is rationally prior to all nonmoral incentives. But Kant thinks evil can be made intelligible to an extent by seeing it as part of nature’s purposiveness in developing human species predispositions in the social condition.