ABSTRACT
Rule-utilitarians hold that moral rules are derived from the principle of utility and that what is right or wrong in particular cases is determined by moral rules. However, rule-utilitarians are not always entirely clear about whether supplementary principles or rules are always needed to determine particular obligations, or whether they are only sometimes needed, or whether indeed they are not really needed at all but may affect particular obligations when and where they exist. In essence, what the act-utilitarian argues is that, if the utilitarian principle determines what is right, then any act which conforms to that principle is right, and any act which does not conform to it is wrong. Therefore, it can make no difference whether or not an act conforms to a rule, even if—and perhaps especially if—that rule is derived from the principle.
