Teleological ethics (Greek telos, “end”; logos, “science”) is a theory of morality that derives duty or moral obligation from what is good or desirable as an end to be achieved. It is opposed to deontological ethics (from the Greek deon, “duty”), which holds that the basic standards for the moral rightness of an action are independent of the good or evil generated by the ethics. Modern ethics, especially since the 18th-century German deontological philosophy of Immanuel Kant, has been deeply divided between a form of teleological ethics (utilitarianism) and deontological theories.
Teleological theories differ on the nature of the end that actions ought to promote. Eudaemonist theories (Greek eudaimonia, “happiness”) hold that ethics consists in some function or activity appropriate to man as a human being, and thus tend to emphasize the cultivation of virtue or excellence in the agent as the end of all action. These could be the classical virtues — courage, temperance, justice, and wisdom — that promoted the Greek ideal of man as the “rational animal”, or the theological virtues — faith, hope, and love — that distinguished the Christian ideal of man as a being created in the image of God.
Utilitarian-type theories hold that the end consists in an experience or feeling produced by the action. Hedonism, for example, teaches that this feeling is pleasure — either one's own, as in egoism (the 17th-century English philosopher Thomas Hobbes), or everyone's, as in universalistic hedonism, or utilitarianism (the 19th-century English philosophers Jeremy Bentham, John Stuart Mill, and Henry Sidgwick), with its formula of the “greatest pleasure of the greatest number.”
Other utilitarian-type views include the claims that the end of action is survival and growth, as in evolutionary ethics (the 19th-century English philosopher Herbert Spencer); the experience of power, as in despotism (the 16th-century Italian political philosopher Niccolò Machiavelli and the 19th-century German Friedrich Nietzsche); satisfaction and adjustment, as in pragmatism (20th-century American philosophers Ralph Barton Perry and John Dewey); and freedom, as in existentialism (the 20th-century French philosopher Jean-Paul Sartre).
The chief problem for eudaemonist theories is to show that leading a life of virtue will also be attended by happiness — by the winning of the goods regarded as the chief end of action. That Job should suffer and Socrates and Jesus die while the wicked prosper, as the Psalmist (73) points out, then seems unjust. Eudaemonists generally reply that the universe is moral and that, in Socrates' words, “No evil can happen to a good man, either in life or after death,” or, in Jesus' words, “But he who endures to the end will be saved.”
Utilitarian theories, on the other hand, must answer the charge that ends do not justify the means. The problem arises in these theories because they tend to separate the achieved ends from the action by which these ends were produced. One implication of utilitarianism is that one's intention in performing an act may include all of its foreseen consequences. The goodness of the intention then reflects the balance of the good and evil of these consequences, with no limits imposed upon it by the nature of the act itself — even if it be, say, the breaking of a promise or the execution of an innocent man. Utilitarianism, in answering this charge, must show either that what is apparently immoral is not really so or that, if it really is so, then closer examination of the consequences will bring this fact to light. Ideal utilitarianism (G.E. Moore and Hastings Rashdall) tries to meet the difficulty by advocating a plurality of ends and including among them the attainment of virtue itself, which, as John Stuart Mill affirmed, “may be felt a good in itself, and desired as such with as great intensity as any other good.”