In the current issue of First Things , David Bentley Hart expresses his skepticism of “the attempt om recent years by certain self-described Thomists, particularly in America, to import [natural law] tradition into public policy debates.” He has in mind the idea that “compelling moral truths can be deduced from a scrupulous contemplation of the principles of cosmic and human nature, quite apart from special revelation, and within the context of the modern conceptual world.” He does not think that the harmony of cosmic and moral order is “as precisely discernible as natural law thinkers imagine” and he denies that “the moral meaning of nature should be perfectly evident to any properly reasoning mind, regardless of religious belief or cultural formation.”

Hart considers the current political use of natural law “a hopeless cause,” and that for several reasons. For one thing, much of what is taken as “natural” is the product of historical events and cultural developments.

It is, he argues, “simply a fact that many of what we take to be the plain and evident elements of universal morality are in reality artifacts of cultural traditions. Today we generally eschew cannibalism, slavery, polygamy, and wars of conquest because of a millennial process of social evolution, the graduate universalization of certain moral beliefs that entered human experience in the form not of natural institutions but of historical events. We have come to find a great many practices abhorrent and a great many others commendable not because the former transparently offend against our nature while the latter clearly correspond to it, but because at various moments in human history we found ourselves address by uncanny voices that seemed to emanate from outside the totality of the perceptible natural order and its material economies.”

Without “specific religious or metaphysical traditions, there really is very little that natural law theory can meaningfully say about the relative worthiness of the employments of the will.” but we can talk about natural law only if there is general agreement about nature, such that there is a bond between “what is and what should be.” He recognizes that there are “generally observable facts about the characteristics of our humanity,” but says that they would be compelling only in a world “in which everyone presumed some necessary moral analogy between the teleology of nature and the proper objects of the will.” That is not, however, the world we live in.

More philosophically, “belief in natural law is inseparable from the idea of nature as a realm shamed by final causes, oriented in their totality toward a single transcendent moral Good: one whose dictates cannot simply be deduced from our experience of the natural order, but must be received as an apocalyptic interruption of our ordinary explanations that nevertheless, miraculously, makes the natural order intelligible to us as a reality that opens up to what is more than natural.” Because of this, “there is no logically coherent way to translate that form of cosmic moral vision into the language of modern ‘practical reason’ or of public policy debate in a secular society.” Every concept of nature depends on “supernatural (or at least metaphysical) convictions.”

So, Hart agrees that there is a “harmony between cosmic and moral order, sustained by the divine goodness in which both participate.” Appeals to natural law are coherent only if they include arguments in favor of a theological vision of creation. That robs natural law of its political usefulness (Hart’s “hopeless cause”), but at the same time it turns appeals to natural law into a form of evangelism or apologetics.