Act v. rule utilitarianism
The distinction has to do with what the principle of utility is applied to.
- According to the act utilitarian (AUian), the principle is applied directly to the selection of particular actions under particular circumstances. (For this reason AU has also been called "direct utilitarianism.")
- According to the rule utilitarian (RUian), the principle is applied to the selection of a set of rules, which are in turn used to determine what to do in particular situations. (And thus RU is sometimes called "indirect utilitarianism.")
Here is a basic description of rule utilitarian reasoning in ethics:
- Make a list of every possible combination of moral rules that you could live by.
These will vary from very simple sets of rules that will fit on a note card, to short lists of rules like the ten commandments, to very complicated codes with clauses covering all kinds of different contingencies or circumstances which will take up huge volumes, the way the U.S. Code of laws does.
- Select that set of rules which, if everyone followed them to eternity, would maximize aggregate utility across the whole of time.
- Then, whatever circumstances you find yourself in, ask yourself, "Is my contemplated action permitted by the set of rules selected in step #2?" If so then your action is permissible. If not, then it is morally wrong.
An imaginative way of seeing this reasoning would be to suppose that you were God, and because you are omnibenevolent, you want your creatures to be as happy as possible in the aggregate across time (that is, you believe in utilitarianism). Now if you were choosing a moral code to teach your created people, what code would you teach them?