What distinguishes morality from ethics?

Many philosophers and political theorists now agree that morality and ethics are not the same. But in virtue of what do morality and ethics — understood as what philosophical and empirical ethics together study — differ? This question is important because unless we answer it, we shall not be able to give an adequate philosophical account of morality. In answer to the question, this paper argues that what distinguishes morality from ethics is that ethics is a set of normative requirements aimed at promoting people's well-being, while morality is the proper subset of ethical normative requirements consisting in the set of all ethical obligations and duties, the aim of which is to reduce the amount of harm persons suffer. The paper defends this thesis by arguing directly for it and by arguing for definitions of ethics and morality which support the thesis.