1. Scholastic natural-law theory’s use of nature as a norm helps explain the negativism and minimalism of classical moral theology. What does not conform to human nature can be forbidden absolutely. What does conform cannot be absolutely required, since people cannot possibly do everything which is permissible; affirmative precepts can require only kinds of action which are specified in such a way that their omission would be wrong. Thus scholastic natural-law theory is far more adept at issuing a few prohibitions than at directing people’s lives toward growth and flourishing. However, an adequate Christian moral theory must not be merely negative. One needs to know affirmatively how to fulfill God’s will; conscience must indicate what is good, pleasing, and perfect (see Rom 12.2).
2. Classical moral theology tends to reduce Christian moral life to a means of gaining heaven and avoiding hell. The absence from scholastic natural-law theory of any intrinsic relationship between the basis of moral norms in human nature and what truly is humanly fulfilling helps explain why. As sanctions for legalistically conceived moral law, heaven and hell can motivate obedience, but they cannot give this present life an inherent meaning. Yet only such meaning can make life in this world intrinsically worthwhile and make Christian life joyful despite inevitable suffering and necessary self-denial.
3. Scholastic natural-law theory’s use of nature as it is given as a source of moral norms helps also to explain the static character of classical moral theology. However, although essential human nature does not change, in the course of human history new possibilities do open up and humankind acquires powers to act in new, more complex ways. An adequate moral theory must look toward possible human fulfillment, and its vision of this must be as dynamic as humankind itself.
4. Classical moral theology is vulnerable to the charge that it is too much concerned with laws and too little with persons. Scholastic natural-law theory’s failure to ground moral norms in human fulfillment explains why. Only an account which shows how morally right acts contribute of themselves to the fulfillment of persons can rebut this charge.