The perspective of the acting person: essays in the renewal of thomistic moral philosophy

5. Practical Reason and the “Naturally Rational”: On the Doctrine of the Natural Law as a Principle of Praxis in Thomas Aquinas

5 Practical Reason and the “Naturally Rational” On the Doctrine of the Natural Law as a Principle of Praxis in Thomas Aquinas Lex naturalis: A Doctrine of the Principles of Practical Reason The debate on the interpretation of the Thomistic doctrine of the lex naturalis that has been going on for the last thirty years has been driven by two things: first, a renewed interest in the specifically philosophical ethics of St. Thomas, and second, the attempt by moral theologians to make the idea of a “natural law” fruitful for understanding the autonomy of the human person as a moral subject. Despite a wide palette of interpretations, a few basic insights have become crystallized, and are approved almost without exception today by anyone familiar with the field.1 The most important of these basic insights would probably be that the doctrine of the lex naturalis is not a doctrine about nature, or about a natural order imparted beforehand to human moral insight and only awaiting human realization, but rather a doctrine of the practical reason of the moral subject and the principles of this reasoning—in other words, a philosophical-ethical doctrine of principles. 1. Editor’s note: This comment refers mainly to German-language scholarship on natural law and Aquinas. 95 Secondly, it may today be accepted in general that practical reason has an independence vis-à-vis theoretical reason, and that practical judgments cannot be derived from theoretical ones, but possess instead their own unassailable starting point. This means that there is a certain parallelism between the theoretical and practical. A third point, in consequence of these two, and here again there is wide consensus, is that the subject matter of ethics cannot be derived from that of metaphysics. Metaphysics—and its corresponding philosophical anthropology—is rather a subsequent illumination and deeper explication of independent, self-experienced practical reasoning by the subject of action.2 While the neo-Thomistic conception of the “natural moral law” seems to be obsolescent in current research, nevertheless in today’s reading of Thomas , the “autonomistic”3 interpretation of the doctrine of natural law that was supposed to have superseded the neo-Thomistic meaning has been increasingly recognized as inadequate. This “autonomistic” position conceived the lex naturalis simply as the natural tendency of the practical reason to formulate ever new moral norms in a creative manner, and finally as the obligation to act according to reason, and treated the natural inclinations of the human person merely as “raw material” for the shaping function of reason.4 In recent years, the exponents of this concept have presented their position 2. Fundamental for this new orientation are: W. Kluxen, Philosophische Ethik bei Thomas von Aquin (Hamburg: Meiner, 1980); G. Grisez, “The First Principle of Practical Reasoning: A Commentary on the Summa Theologiae, 1–2, Question 94, article 2,” Natural Law Forum 10 (1965): 168–201, a slightly abridged version of which is in A. Kenny, ed., Aquinas: A Collection of Critical Essays (Garden City, N.Y.: Anchor Books, 1969); J. Finnis, Natural Law and Natural Rights (Oxford: Clarendon, 1980). The most prominent opponent of the thesis of a parallelism of theoretical and practical reasoning is R. McInerny: cf. for example “The Principles of Natural Law,” American Journal of Jurisprudence 25 (1980): 1–15; Ethica Thomistica: The Moral Philosophy of Thomas Aquinas (Washington, D.C.: The Catholic University of America Press, 1982); and Aquinas on Human Action: A Theory of Practice (Washington, D.C.: The Catholic University of America Press, 1992), esp. 184ff. In the same perspective, cf. R. Hittinger, A Critique of the New Natural Law Theory (Notre Dame, Ind.: University of Notre Dame Press, 1987). 3. Editor’s note: By using the term “autonomistic” instead of “autonomous,” Rhonheimer wants to distinguish that it is not the “position” of these theologians that is “autonomous.” Rather , they understand man to be autonomous. Therefore, by “autonomistic” Rhonheimer means to indicate “autonomism” in the sense of an ideology. 4. F. Böckle, Das Naturrecht im Disput (Düsseldorf: Patmos-Verlag, 1966); Böckle, “Natürliches Gesetz als göttliches Gesetz in der Moraltheologie,” in F. Böckle and E.-W. Böckenförde, eds., Naturrecht in der Kritik (Mainz: Matthias Grünewald, 1973), 165–88; Böckle, Fundamentalmoral (Munich: Kösel, 1977); K.-W. Merks, Theologische Grundlegung der sittlichen Autonomie. Strukturmomente eines “autonomen” Normbegründungsverständnisses im lex-Traktat der Summa Theologiae des Thomas von Aquin (Düsseldorf: Patmos-Verlag, 1978). 96 the “naturally rational” [3.141.202.187...