My question is whether a prevalent conception of morality can admit the existence of moral delusion. The conception of morality I refer to is that of a set of rules, or principles, ‘accepted’ or ‘assented’ to by persons, which stipulate that certain kinds of human act or behaviour are permitted, or required, while other kinds are to be avoided. This conception of morality can be found virtually everywhere, outside as much as within philosophy, in anthropology, sociology, political studies, history, literary criticism, psychology, and law. But it is to a particular philosophical instance that I shall attend here. The instance in question is an essay by Jonathan Bennett which appeared in this journal seven years ago under the title ‘The Conscience of Huckleberry Finn’. My reason for addressing myself to Bennett's paper will become clear as I proceed.