Aquinas's Theory of Natural Law. - book reviews

Anthony J. Lisska, Oxford: Clarendon Press, 1996. 320pp. $60.00. (cloth).

The ethics of Thomas Aquinas have been put to many and not always compatible uses in the second half of the twentieth century. It is at times not obvious how the divergent strands of Thomistic ethics are related to one another or, indeed, comprise a unified tradition and reasonably coherent community of discourse beyond common reliance on the same texts of St. Thomas. It is the distinction of Anthony Lisska's fine book that it gives some clarity and order to the manifold expressions of Thomistic ethics in the last thirty years or so, particularly concerning the issue of natural law theory.

Lisska's purpose is to provide a conceptual reconstruction of Aquinas' natural law theory that is intelligible to Anglo-American analytic philosophers. To this end, Lisska reconstructs the moral theory and mounts an extensive argument against the dominant "anti-naturalism" of analytic meta-ethics. In this effort he shows considerable patience and evenhandedness in examining the views of earlier twentieth-century thinkers, such as Hart, Lon Fuller, and Jacques Maritain, as well as contemporaries like Ronald Dworkin, John Finnis, and Hilary Putnam. Lisska's comprehensive survey and analysis includes both the major philosophical arguments against natural law theory (most notably G. E. Moore's "naturalist fallacy" argument) as well as the major efforts to rehabilitate natural theory against its contemporary detractors. His constructive position depends, in different ways, on the work of Alisdair MacIntrye (especially his criticism of the "Enlightenment project"), Ralph McInerny (notably his rejection of the "transcendental turn" of modern philosophy and its attendant anti-realism), and, most importantly, Henry Veatch (especially "ontological foundationalism").

Aquinas's Theory of Natural Law has the admirable qualities of attention to detail, fair-mindedness, nuance, and comprehensiveness. The author recognizes the close dependence of natural law jurisprudence on prior philosophical commitments and takes the necessary pains to spell out their various lines of connection. In this effort, Lisska points to (but does not spell out) the practical significance of natural law ethics for both civil law and practical moral life.

Lisska's book provides a detailed explication of Thomistic natural law ethics, using categories taken from analytic philosophy in order to provide a moral theory that is clear and coherent enough to be persuasive to serious contemporary secular moralists. The heart of his argument against the "anti-naturalism" of Moore and his contemporary disciples is that the natural law theory, properly understood, does not commit the "naturalist fallacy" because it does not attempt to deduce "ought statements" from purely descriptive "is statements." Lisska grants that Moore's criticism was indeed applicable to the earlier naturalism of Herbert Spencer and the utilitarians but he insists that it is not relevant to Thomistic naturalism, whose "dispositional theory of essential properties" (the "metaphysics of finality") holds that natural ends include both descriptive and normative dimensions. Most analytic critiques of "essentialism" have assumed, with Russell, Moore, and Quine that essential properties are static. Lisska attempts to pull the rug out from under this criticism - and the positions of people like Finnis and Grisez who grant it - by arguing that for Aquinas an "essence" is a set of "synthetic a priori properties" (together constituting, in the parlance of philosophers Kripke and Putnam, a "natural kind") that is dispositional rather than static in character. Put succinctly: "The value as fact is a state of completion of the disposition as fact" (199).

Natural ends provide the basis of moral obligation and therefore, Lisska argues, the will of God is neither necessary nor even relevant to natural law ethics. He thus explicitly and intentionally rejects the necessity of theological backing for natural law theory. While the Summa theologiae clearly based the natural law on the eternal law, Lisska argues that, philosophically speaking, Thomas could have provided a nontheistic account of the natural law without ethical loss. This "conceptual secularism" undercuts the common attempt by critics to rule natural law theory out of court on the grounds that it is irreducibly religious. Though it is metaphysically grounded, in Lisska's view, natural law theory provides an ethics "within the limits of reason alone" and cannot be dismissed as dependent on theological (i.e., nonrational) premises. Lisska's point: "Aquinas's metaphysics is not totally removed from the mainstream concerns of contemporary analytic philosophy" (125). Natural law, we can read between the lines, is not the concoction of a few idiosyncratic and rigidly conservative Catholics. It is in the mainstream and to be taken seriously by the academy.

Assessment of this kind of book is difficult since it stands alone in its own genre and therefore cannot be compared to similar efforts. Lisska deserves a great deal of credit for taking on a project this ambitious and for his unswerving commitment to fairness in dealing with his intellectual adversaries. The most significant weakness of the book is its very quick rejection of the modern "turn to the subject," an epistemological commitment which serious thinkers like Lonergan and Rahner (neither of whom is mentioned in the book) argue need not degenerate into philosophical idealism or anti-realism. The book could have gone even further by showing the practical relevance of this theory for concrete moral issues. It would have been interesting, for example, to see how Lisska's natural law theory would contrast with, say, Dworkin's defense of physician-assisted suicide or with Finnis's argument that artificial contraception is always ethically illegitimate.