There are striking structural similarities between Freud's ego and Kant's transcendental unity of apperception, which for Kant grounds our use of ‘I’ in ‘I think’. There are also striking similarities between Freud's superego and Kant's account of the mental structure that grounds our use of ‘I’ in the moral ‘I ought to’. The paper explores these similarities on three main points: the conflict of motivations internal to the mind, the relation between discursive and pre-discursive representation of moral motivation, and the unconscious character of moral motivation. The suggestion is that Freud offers resources for a naturalized account (an account in terms of the causal development of empirical human beings) of just those features of our moral motivation that, according to Kant, seem to make it least amenable to a naturalistic explanation. How much of a revision of Kant's analysis of moral justification is thereby entailed is beyond the purview of the paper.