Utilitarianism is often described by the phrase "the greatest good for the greatest number of people", 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.
Preference utilitarianism is one of the most popular forms of utilitarianism in contemporary philosophy. In the same way as other utilitarian theorists, preference utilitarians define a morally right action as that which produces the most favorable consequences for the people involved. However, preference utilitarians interpret the best consequences in terms of 'preference satisfaction'. This means that 'good' is described as the satisfaction of each person's individual preferences or desires, and a right action is that which leads to this satisfaction. Since what is good depends solely on individual preferences, there can be nothing that is in itself good or bad except for the resulting state of mind. Preference utilitarianism therefore can be distinguished by its acknowledgment that every person's experience of satisfaction will be unique.
Rule utilitarianism is a form of utilitarianism which states that moral actions are those which conform to the rules which lead to the greatest good, or that "the rightness or wrongness of a particular action is a function of the correctness of the rule of which it is an instance." For rule utilitarians, the correctness of a rule is determined by the amount of good it brings about when followed. In contrast, act utilitarians judge actions in terms of the goodness of their consequences without reference to rules of action. Another variation of rule utilitarianism stresses the greater utility of following a given rule in general, arguing that the practice of following some rule in all instances (always stopping at red lights,...