Moral worth is a kind of goodness that is predicated of persons. Rawls claims that after the good and the right, moral worth is the third main concept of ethics and develops it as part of his conception of goodness as rationality. According to this, a good or morally worthy person is someone who has to a higher degree than the average the broadly based features of moral character that it is rational for members of a well-ordered society to want in one another (TJ 383–384). Such broadly based features are the moral virtues.

In extending the conception of goodness as rationality to persons Rawls does not assume that a person as such has some definite role or function in light of which we might say that someone is good as a person because he has the properties that it is rational to want for performing such a role. Nor does he start from a basic role of persons (or a set of most important roles), such as that of citizen, in order to identify the properties that it is rational for persons to want in one another. Instead, he surmises that “there may exist properties which it is rational to want in persons when they are viewed with respect to almost any of their social roles” (TJ 382). The idea of a well-ordered society provides the point of view from which the “broadly based” properties are to be identified. In such a society, it is rational for its members to want others to act upon the principles of right and justice and to have the corresponding moral virtues; in particular, it is rational for them to want others to have a sense of justice. Though this perspective does not single out the role of citizenship, the former includes the latter. Since the extension is possible through the use of the principles of right and justice, the concept of moral worth belongs to the full theory of the good. A morally good or worthy person, on this view, is someone who has to a higher degree than average the moral virtues as determined by the principles of right and justice. Since in a well-ordered society all its members have the appropriate sense of justice, everyone has the same moral worth (TJ 274–275).