Act Utilitarianism versus Rule Utilitarianism

A central division within utilitarian theory concerns what, exactly, the principle of utility is meant to evaluate. Act utilitarianism holds that the rightness of a particular action depends directly on the consequences of that very action, calculated afresh in each case: an agent should always perform whichever available act will produce the greatest net balance of good over bad consequences. Rule utilitarianism, by contrast, holds that an action is right if it conforms to a general rule of conduct whose widespread acceptance and general observance would tend to maximize welfare overall, even if breaking that rule in a particular instance might, by itself, produce a marginally better outcome. The terminology crystallized in the mid-twentieth century, notably through J.O. Urmson's 1953 essay "The Interpretation of the Moral Philosophy of J.S. Mill," which controversially argued that Mill himself, in Utilitarianism, held something closer to a rule-utilitarian than a strictly act-utilitarian position, a reading that has since been extensively debated by Mill scholars.