Of all our theological disciplines Christian ethics appears to be the one most open to attack. However careful the modern exponents of Calvinism have been in setting forth the truths of God's sovereignty and human depravity, they have sometimes used language which suggests that, since all good actions are the outcome of God's grace, ‘Christianity transcends morality altogether, and there is no such thing as a Christian ethic’. Again the apparently rigorous determinism of both Dialectical Materialism and Freudian Psychology has been interpreted in popular thought as removing every possibility of moral responsibility, for men's actions are thought to be as mechanistically determined as all other events in physical nature. Today the emphasis on personal decision in much existentialist thought is a welcome reaction against such determinisms whether theological or scientific. Yet the very demand for a new recognition of human freedom has sparked off a new attack on the Christian ethic, at any rate as this has been taught in the tradition of the Church. This ethic is now being labelled authoritarian, puritan, legalistic, rigoristic, heteronomous and the like, and it is taken for granted that these are all derogatory terms. If we are to seek a slogan for this new attack, we cannot find a better one than the familiar, if not quite accurate, translation of the saying of St. Augustine, ‘Love and do what you like’, and it is by examining this principle, that we shall try to gain some light on the position of Christian ethics today.