http://en.wikipedia.org/wiki/UtilitarianismUtilitarianism is the idea that the moral worth of an action is determined solely by its contribution to overall utility: that is, its contribution to happiness or pleasure as summed among all people. It is thus a form of consequentialism, meaning that the moral worth of an action is determined by its outcome.
Utilitarianism is often described by the phrase "the greatest good for the greatest number of people", and is also known as "the greatest happiness principle". Utility, the good to be maximized, has been defined by various thinkers as happiness or pleasure (versus suffering or pain), although preference utilitarians define it as the satisfaction of preferences. It may be described as a life stance, with happiness or pleasure being of ultimate importance.
Utilitarianism can be characterised as a quantitative and reductionist approach to ethics. It can be contrasted with deontological ethics (which do not regard the consequences of an act as the sole determinant of its moral worth) and virtue ethics (which focuses on character), as well as with other varieties of consequentialism. Adherents of these opposing views have extensively criticised the utilitarian view, but utilitarians have been similarly critical of other schools of thought. And like any ethical theory, the application of utilitarianism is heavily dependent on the moral agent's full range of wisdom, experience, social skills, and life skills.
In general usage, the term utilitarian refers to a somewhat narrow economic or pragmatic viewpoint. Philosophical utilitarianism, however, is a much broader view that encompasses all aspects of people's lives.