Abstract

The natural law tradition is not monolithic but pluralistic. For proponents of natural law theory have approached the concept of natural law in different ways, depending on whether primacy is given to the notions of right and duty or to the notions of good and human finality. Those who give primacy to the notion of duty may be viewed as advocating a "thin" theory of natural law. In contrast, those who give primacy to the metaphysical notion of the good may be regarded as arguing for a "thick" theory of natural law. Several scholars of note, including F. Russell Hittinger and Servais Pinckaers, would tend to agree with the claim that Thomas Aquinas, unlike those who favor a chiefly deontological natural law theory, defended a "thick" natural law theory. The notion of human finality lies at the very foundation of Thomas' natural law theory, which is embedded within a properly theological setting. ;One may ask, however, whether unaided reason in principle is capable of formulating or recognizing a valid defense of a "thick" natural law theory. Stated differently, can a "thick" natural law theory stand on human reason without relying on what Thomas would regard as the superadded light of divine revelation? From a Thomistic standpoint the answer to this question depends on whether human reason left to its own resources can construct a valid proof that man in principle can find his ultimate completion in the Supernatural, a transcendent good conceived as a final end proportionate to human nature. On this key issue Thomistic interpreters are divided. From a Thomistic standpoint, however, it is arguably the case that without reference to the Supernatural in some sense, a "thick" natural law theory cannot withstand careful philosophical scrutiny. ;In this study I argue that a certain conception of man's final end, one that stands midway between Aristotelian eudaimonia and Christian beatitudo, is defensible on strictly philosophical grounds. If that is correct, it lends critical support to the claim that a "thick" natural law theory can in principle be defended without incorporating properly theological argumentation