David lyons has recently argued that mill's ethics is an alternative to both act and rule utilitarianism. In the first part of this paper I argue that lyons makes mill out to be far too much of a rule utilitarian. The second part of the article then provides an account of mill's theory of moral rules based on an analysis of the four functions rules serve in his ethics. On this reading mill's theory is a hybrid of act and rule (...) utilitarianism: violation of a moral rule is a necessary but not a sufficient condition for wrongdoing. (shrink)