Utilitarianism
Utilitarianism is a type of consequentialist ethical theory. According to such theories, only the outcome of an action is morally relevant (this contrasts with deontology, according to which moral actions flow from duties or motives). Utilitarianism is a combination of consequentialism and the philosophical position hedonism, which states that pleasure, or happiness, is the only good worth pursuing. Therefore, since only the consequences of an action matter, and only happiness matters, only happiness that is the consequence of an action is morally relevant. Although the same process could also be applied to preference utilitarianism where utility is defined as individual preference rather than pleasure.
The two predecessor theories to two-level utilitarianism, act and rule utilitarianism, were beset by various objections. For example, rule utilitarianism was criticized for implying that in some cases an individual should pursue a course of action that would obviously not maximise utility. Conversely, act utilitarianism was criticized for not allowing for a 'human element' in its calculations, i.e. it is sometimes too difficult (or impossible) for an ordinary person with imperfect knowledge to calculate the action of maximal utility.
Read more about this topic: Two-level Utilitarianism