There are two main meanings in Kant’s concept of moral certainty (moralische Gewissheit, certitudo moralis): first, it applies to the kind of certainty embodied in rational faith in the existence of God and a future life; second, it applies to the conscientiousness (Gewissenhaftigkeit) required of an agent in the practice of moral judgement. Despite the growing attention to Kant’s theory of conscience and his concept of conscientiousness, this article is the first to discuss ‘moral certainty’ as the aim of ‘conscientiousness’ and to highlight the relevance of both notions in regard to moral education and the purposes of Kant’s ethical doctrines of method.

In this article I argue that Kant’s understanding of the universality of radical evil is best understood in the context of human sociality. Because we are inherently social beings, the nature of the human community we find ourselves in has a determinative influence on the sorts of persons we are, and the kinds of choices we can make. We always begin in evil. This does not vitiate responsibility, since through reflection we can become aware of our situation and envision ourselves as members of a different community, one with different expectations, making genuine virtue possible. This understanding of radical evil helps to make sense of Kant’s high regard for the church in Religion.

In this article, I assess three contemporary criticisms levelled at Kant’s theory of evil in order to evaluate whether his theory can be saved. Critics argue that Kant does not adequately distinguish between evil and mundane wrongdoing, making his use of the term ‘evil’ emotional hyperbole; by defining evil as the subordination of the moral law to self-love his analysis is seemingly overly simplistic and empirically false; and by focusing solely on the moral character of the perpetrator of evil, Kant’s theory apparently ignores the most salient aspect of evil – the suffering of victims. While I will not claim that Kant provides us with a fully adequate theory of evil, I respond to each of these criticisms and conclude that Kant’s theory can still provide significant insight into both the nature of evil and the moral psychology of perpetrators of evil.

The notion of radical evil plays a more important role in Kant's moral theory than is typically recognized. In Religion Within the Limits of Mere Reason, radical evil is both an innate propensity and a morally imputable act – a paradoxical status that has prompted commentators to reject it as inconsistent with the rest of Kant's moral theory. In contrast, I argue that the notion of radical evil accounts for the beginning of moral responsibility in Kant's theory, since the act of attributing radical evil to one's freedom is an inauguration into the autonomous stance.