Act Utilitarianism

Principle of Utility
Rule and act utilitarianism both have in common the principle of utility. the difference between the two is what the rule of utility is applied to. According to the rule utilitarianism the principle of utility is applied to a set of rules, which are in turn used to determine what to do in particular situations. A simple set of instructions can be set up for Rule utilitarianism as follows:

1. Make a list of all the possible moral rules you could live by.

2. Select the set of rules that if everyone were to follow for eternity would result in the maximum amount of happiness.

3.Then, whatever circumstances you are in, ask yourself  are my actions permitted by the selected rules in step 2? If so then your actions are morally good.

Rule Utilitarianism Stems from Act Utilitarianism
Much of the time act and rule utilitarianism are seen as two different approaches in deciding what is morally right or wrong but in fact one simply stems from the other. Even though rule utilitarianism attempts to lay out a set of rules to be followed, these rules can easily be changed if the outcome evidently fails to bring about the greatest happiness for the greatest number of people. So for J.S.Mill i guess it's back to square one.

Strong and Weak Rule Utilitarianism
Rule utilitarianism can be strong and weak. Strong rule utilitarianism is more absolute as it doesnt allow the breaking of the set rules under any conditions. On the contrary weak rule utilitarianism permits the breaking of rules in rare cases. This leans more towards act utilitarianism as it is more subjective and relative. Act utilitariansim can not be split into these characteristics as it does not have a fixed set of rules and so no code of conduct can be followed in a strong or weak sense initially.