Consequentialism (or Teleological Ethics) is an approach to Ethics that argues that the morality of an action is contingent on the action's outcome or consequence. Thus, a morally right action is one that produces a good outcome or result, and the consequences of an action or rule generally outweigh all other considerations (i.e. the ends justify the means).

It is distinct from the other main types of ethical system: Deontology (which derives the rightness or wrongness of an act from the character of the act itself rather than the outcomes of the action), and Virtue Ethics (which focuses on the character of the agent rather than on either the nature or consequences of the action itself). Consequentialist theories must consider questions like "What sort of consequences count as good consequences?", "Who is the primary beneficiary of moral action?", "How are the consequences judged and who judges them?"

Agent-Neutral Consequentialism ignores the specific value of a state of affairs for the individual, so that their own personal goals do not count any more than anyone else's goals in evaluating what action should be taken. Agent-Focused Consequentialism, on the other hand, focuses on the particular needs of the individual, so that (although they may also be concerned with the general welfare) they are more concerned with the immediate welfare of the individuals' self, friends and family.

The term "consequentialism" was coined by Elizabeth Anscombe (1919 - 2001) in her 1958 essay "Modern Moral Philosophy", as a pejorative description of what she saw as the central error of certain moral theories (she was a Virtue Ethicist). It then came to be adopted by both sides of the argument.

Some consequentialist theories include:

• Utilitarianism, which holds that an action is right if it leads to the most happiness for the greatest number of people ("happiness" here is defined as the maximization of pleasure and the minimization of pain).
• Hedonism, which is the philosophy that pleasure is the most important pursuit of mankind, and that individuals should strive to maximise their own total pleasure (net of any pain or suffering). Epicureanism is a more moderate approach (which still seeks to maximize happiness, but which defines happiness more as a a state of tranquillity than pleasure).
• Egoism, which holds that an action is right if it maximizes good for the self. Thus, Egoism may license actions which are good for an individual even if detrimental to the general welfare.
• Asceticism, in some ways, the opposite of Egoism in that it describes a life characterized by abstinence from egoistic pleasures especially to achieve a spiritual goal.
• Altruism, which prescribes that an individual take actions that have the best consequences for everyone except for himself, according to Auguste Comte's dictum, "Live for others". Thus, individuals have a moral obligation to help, serve or benefit others, if necessary at the sacrifice of self-interest.
• Rule Consequentialism, which is a theory (sometimes seen as an attempt to reconcile Consequentialism and Deontology), that moral behaviour involves following certain rules, but that those rules should be chosen based on the consequences that the selection of those rules have. Some theorists holds that a certain set of minimal rules are necessary to ensure appropriate actions, while some hold that the rules are not absolute and may be violated if strict adherence to the rule would lead to much more undesirable consequences.
• Negative Consequentialism, which focuses on minimizing bad consequences rather than promoting good consequences. This may actually require active intervention (to prevent harm from being done), or may only require passive avoidance of bad outcomes.

Some Virtue Ethicists hold that Consequentialist theories totally disregard the development and importance of moral character. Phillipa Foot (1920 - ), for example, argues that consequences in themselves have no ethical content, unless it has been provided by a virtue, such as benevolence, etc.

Others have argued that Consequentialism is unable to explain adequately why a morally wrong action is morally wrong, and attempts to do so lead to absurdity, such as the example of an "obliging stranger" who agrees to be baked in an oven.

Elizabeth Anscombe (1919 - 2001) has objected to Consequentialism on the grounds that it does not provide guidance in what one ought to do, since the rightness or wrongness of an action is determined based solely on the consequences it produces.

Bernard Williams (1929 - 2003) has argued that Consequentialism is alienating because it requires moral agents to put too much distance between themselves and their own projects and commitments, and to take a strictly impersonal view of all actions.

Others argue that Consequentialism makes no distinction between consequences that are foreseen and those that are intended (e.g. relieving a terminally ill patient's pain may also cause an effect one would normally be obliged to avoid, namely the patient's death: the Principle of Double Effect).

Still others have argued that Consequentialism fails to appropriately take into account the people affected by a particular action (e.g. a Consequentialist cannot really criticize human rights abuses in a war if they ultimately result in a better state of affairs).