Along with the principle of the right, the principle of the good constitutes one of the two fundamental principles of deductive theories of ethics. In modern moral thought (which has been dominated by Consequentialism and Deontology), these principles are considered fundamental because it is assumed that only they enable us to explain moral worth (i.e., why something has moral value). It is presumed, then, that the structure of a deductive ethical theory depends on how it relates these two principles. Accordingly, if such an ethical theory gives priority to the principle of the good, then that theory is a form of consequentialism. On the other hand, if the theory gives the principle of the right priority, then the theory is deontological in nature. [Source: Rawls, J. A Theory of Justice (Cambridge: Harvard University Press, 1971), 24.]
Some authors argue, however, that this "grand modern bifurcation of ethics" precludes the possibility of an equally valid way of conceiving of the good. These authors argue that, rather than conceiving of the good as a universal, fundamental principle, i.e., a principle from which particular judgments of action should always be derived, the good can also be conceived of in terms of the good life or the ultimate end toward which human life is inherently directed. [Source: Finnis, J. Fundamentals of Ethics (Georgetown: Georgetown University Press, 1983), 84.] For example, Aristotle thought that the good, in the sense of that to which all things aim, was human flourishing, i.e., a life consisting of valuable activity. The emphasis in such a conception of the good is not on any resulting state of affairs per se, such as pleasure, wealth, or popularity, but on how well one lives one’s life. Thus, Teleology, proper speaking, needs to be distinguished from Consequentialism, which is only one form of "ends-centered" ethic. St. Thomas Aquinas held a similar conception but posited "Beatitude," or divine union with God, as the Ultimate End (the summum bonum). Traditionally, this is the way the good has been understood in Catholic moral theology. This way of conceiving of the good requires that human persons act in ways that both conform with some duties, usually absolute principles of prohibition, e.g., do not kill innocent life, and also act so as to bring about favorable resulting states of affairs.