Philosophical Ethics: Rule and Act Utilitarianism



Utilitarianism mugIn act-utilitarianism, we are required to promote those acts which will result in the greatest good for the greatest number of people. The consequences of the act of giving money to charity would be considered right in act-utilitarianism, because the money increases the happiness of many people, rather than just yourself.

To see the utility of an action as only a criterion for rightness is to regard the maximisation of utility as what makes an action right. This leaves open the question of how one is to incorporate utilitarianism into one’s life.


Rule-utilitarianism is a reaction to that objection. The principle of utility in rule-utilitarianism is to follow those rules which will result in the greatest good for the greatest number of people. In the example above, the general rule would be: ‘share your wealth’. Utilitarianism holds that whatever produces the greatest utility (pleasure or any other such value as defined and justified by the utilitarian) is good and that which produces the greatest nett utility, is considered right. Both theories count as utilitarian because both define that which produces the greatest utility as good and seek for the greatest nett amount of utility, be it either through actions or indirectly through rules.

One objection to rule-utilitarianism is that in some situations the utility of breaking a certain rule could be greater than keeping it. It is, for example, not difficult to imagine that a rule-utilitarian who lives by the rule ‘tell the truth’, sometimes will find him or herself forced to lie in order to increase utility. John Smart argues that refusal to break a generally beneficial rule in cases where it would be beneficial to do so seems irrational for a utilitarian and is a form of rule-worship.

When a rule-utilitarian is compelled to break a rule, he or she will be forced to modify the rule in order to repair the theory. This rule-modifying will continue as long as there are situations where the rules do not produce the greatest utility. The rule for promise-keeping, for example, would be of the form: “Always keep your promises except …”; with a very long list of exceptions. The rule-breaking is necessary in order to maintain the greatest utility. A plausible formulation of rule-utilitarianism would thus have it recommend the same actions as act-utilitarianism. The two kinds are extensionally equivalent and the only stable rule available to the rule-utilitarian is the act-utilitarian one, e.g. to maximise the benefit of your actions.

The rule-utilitarian might defend the theory by saying that it is beneficial to follow the rule in most cases, so the general good is still increased when looking at a series of situations. Another reply might be that it is better that everybody follows the rule than that nobody should, as the latter situation would certainly not be beneficial to the greater good of all. Other reasons sometimes put forward include: rules overcome the need to constantly do a ‘cost-benefit’ utility analysis, which can be impractical; they may overcome our inability to calculate the consequences our actions will have on other people’s welfare; and they may overcome our inability to act without prejudice, self interest and failure of imagination.

  1. This paper has been written for the course Ethics by Monash University, Melbourne. []

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