In a piece in the March issue of First Things, David Bentley Hart suggests that the arguments of natural law theorists are bound to be ineffectual in the public square. The reason is that such arguments mistakenly presuppose that there is sufficient conceptual common ground between natural law theorists and their opponents for fruitful moral debate to be possible.

In particular, they presuppose that “the moral meaning of nature should be perfectly evident to any properly reasoning mind, regardless of religious belief or cultural formation.” In fact, Hart claims, there is no such common ground, insofar as “our concept of nature, in any age, is entirely dependent upon supernatural (or at least metaphysical) convictions.”

For Hart, it is only when we look at nature from a very specific religious and cultural perspective that we will see it the way natural law theorists need us to see it in order for their arguments to be compelling. And since such a perspective on nature “must be received as an apocalyptic interruption of our ordinary explanations,” as a deliverance of special divine revelation rather than secular reason, it is inevitably one that not all parties to public debate are going to share.

Now I have nothing but respect for Prof. Hart and his work. But this latest article is not his finest hour. Not to put too fine a point on it, by my count he commits no fewer than five logical fallacies: equivocation, straw man, begging the question, non sequitur, and special pleading.

He equivocates insofar as he fails to distinguish two very different theories that go under the “natural law” label. He also uses terms like “supernatural” and “metaphysical” as if they were interchangeable, or at least as if the differences between them were irrelevant to his argument.

These ambiguities are essential to his case. When they are resolved, it becomes clear that with respect to both versions of natural law theory, Hart is attacking straw men and simply begging the question against them. It also becomes evident that his conclusion—that it is “hopeless” to bring forth natural law arguments in the public square—doesn’t follow from his premises, and that even if it did, if he were consistent he would have to apply it to his own position no less than to natural law theory.

Let’s consider these problems with Hart’s argument in order. Who, specifically, are the “natural law theorists” that he is criticizing? He assures us that “names are not important.” In fact names are crucial, because it is only by running together the two main contemporary approaches to natural law that Hart can seem to have struck a blow against either.

So let’s name names. What we might call the classical (or “old”) natural law theory is the sort grounded in a specifically Aristotelian metaphysics of formal and final causes—that is to say, in the idea that things have immanent natures or substantial forms and that in virtue of those natures they are inherently directed toward certain natural ends, the realization of which constitutes the good for them. Accordingly, this approach firmly rejects the so-called “fact/value dichotomy” associated with modern philosophers like Hume.

Classical natural law theory’s most prominent historical defender is Aquinas, and it was standard in Neo-Scholastic manuals of ethics and moral theology in the pre-Vatican II period. In more recent decades it has been defended by writers like Ralph McInerny, Henry Veatch, Russell Hittinger, David Oderberg, and Anthony Lisska. (In the interests of full disclosure—of which, regrettably, self-promotion is a foreseen but unintended byproduct, justifiable under the principle of double effect—I suppose I should mention that I have also defended classical natural law theory in several places, such as my book Aquinas.)

What has come to be called the “new natural law theory” eschews any specifically Aristotelian metaphysical foundation, and in particular any appeal to formal and final causes and thus any appeal to human nature (at least as “old natural law” theorists would understand it). It is a very recent development—going back only to the 1960s, when it was invented by Germain Grisez—and its aim is to reconstruct natural law in terms that could be accepted by someone who affirms the Humean fact/value dichotomy.

In addition to Grisez, new natural law theory is associated with writers like John Finnis, Joseph Boyle, William May, Robert P. George, and Christopher Tollefsen. (Once again in the interests of full disclosure, I should note that like other classical natural law theorists, I have been very critical of the so-called “new natural lawyers.” But it is also only fair to point out that Hart’s argument has no more force against the “new” natural law theory than it does against the “old” or classical version.)

What the two approaches have in common is the view that objectively true moral conclusions can be derived from premises that in no way presuppose any purported divine revelation, any body of scriptural writings, or any particular religious tradition. Rather, they can in principle be known via purely philosophical arguments.

Where the two approaches differ is in their view of which philosophical claims, specifically, the natural law theorist must defend in order to develop a system of natural law ethics. The “old” natural law theorist would hold that a broadly classical, and specifically Aristotelian, metaphysical picture of the world must be part of a complete defense of natural law. The “new” natural law theorist would hold that natural law theory can be developed with a much more modest set of metaphysical claims—about the reality of free will, say, and a certain theory of practical reason—without having to challenge modern post-Humean, post-Kantian philosophy in as radical and wholesale a way as the “old” natural law theorist would.

Both sides agree, however, that some body of metaphysical claims must be a part of a complete natural law theory, and (again) that these claims can be defended without appeal to divine revelation, Scripture, etc.

Now Hart characterizes natural law theory in general as committed to the reality of final causes, indicates that he affirms their reality himself, but then (bizarrely) appeals to Hume’s fact/value dichotomy as if it were obviously consistent with affirming final causes, uses it as a basis for criticizing natural law theorists for supposing conceptual common ground with their opponents, and concludes that it is only by reference to controversial “supernatural (or at least metaphysical) convictions” that natural law theory could be defended. This is a tangle of confusions.

For one thing, if there were a version of natural law theory that both appealed to final causes in nature and at the same time could allow for Hume’s fact/value dichotomy, then Hart’s argument might at least get off the ground. But there is no such version of natural law theory, and it seems that Hart is conflating the “new” and the “old” versions, thereby directing his attack at a phantom position that no one actually holds. The “new natural lawyers” agree with Hume and Hart that one cannot derive an “ought” from an “is,” but precisely for that reason do not ground their position in a metaphysics of final causes. The “old” or classical natural law theory, meanwhile, certainly does affirm final causes, but precisely for that reason rejects Hume’s fact/value dichotomy, and in pressing it against them Hart simply begs the question.

It seems Hart thinks otherwise because he supposes that even if our nature directs us to certain ends that constitute the good for us, reason could still intelligibly wonder why it ought to respect those natural ends or the good they define. But this implicitly supposes that reason itself, unlike everything else, somehow lacks a natural end definitive of its proper function, or at least a natural end that we can know through pure philosophical inquiry. And that is precisely what classical natural law theory denies.

In the view of the “old” natural law theorist, when the metaphysics of intellect and volition are properly understood, it turns out that it cannot in principle be rational to will anything other than the good. The fusion of “facts” and “values” goes all the way down, without a gap into which the Humean might fit the wedge with which he’d like to sever practical reason from any particular end. Hart simply assumes that this is false, or at least unknowable; he doesn’t give any argument to show that it is. And thus he has offered no non-circular criticism of the classical natural law theorist.

Of course such a non-Humean view of practical reason is controversial—though I defend it in Aquinas, and other classical natural law theorists have defended it as well—but the fact that it is controversial is completely irrelevant to the dispute between Hart and natural law theory. For no natural law theorist denies that some controversial metaphysical conclusions have to be defended in order to defend natural law theory. That is true of any moral theory, including secular theories, and including whatever approach it is that Hart favors. Certainly it is true of the Humean thesis about “facts” and “values,” which is just one controversial metaphysical claim among others. Having to appeal to controversial metaphysical assumptions is in no way whatsoever a special problem for natural law theorists.

It also has nothing whatsoever to do with claims about the supernatural order. Sloppy popular usage aside, “supernatural” is not a synonym for “metaphysical”—as Hart himself implicitly acknowledges with the phrase “supernatural (or at least metaphysical),” quoted above. What is supernatural is what is beyond the natural order altogether, and thus cannot be known via purely philosophical argument but only via divine revelation. Metaphysics, by contrast, is an enterprise that Platonists, Aristotelians, materialists, idealists, philosophical theists, atheists, and others have for millennia been engaged in without any reference to divine revelation. So for Hart to insinuate that its dependence on metaphysical premises entails that natural law rests on divine revelation, “supernatural” foundations, or “an apocalyptic interruption of our ordinary explanations” is simply a non sequitur.

On the other hand, if all Hart means to assert is that natural law theorists suppose that the metaphysical commitments crucial to their position are uncontroversial, then he is attacking a straw man. No natural law theorist claims any such thing. What they claim is merely that, however controversial, their position can be defended via purely philosophical arguments and without resort to divine revelation. And if its being controversial makes it “hopeless” as a contribution to the public square, then every controversial position is hopeless.

Including Hart’s. Which brings us to special pleading. For what exactly is Hart’s alternative approach to moral debate in the public square, and how is it supposed to be any better? Is a theological position like his—with its appeal to the supernatural, to “apocalyptic interruptions,” and the like—less controversial than natural law theory? Is it more likely to win the day in the public square? To ask these question is to answer them.

Nor could Hart plausibly retreat into a quietist position that refuses to engage with those who do not already share his fundamental commitments. For one thing, there is nothing quiet about his book Atheist Delusions, which was presumably intended as a contribution to the public debate over the New Atheism, not as a mere sermon to the circle of his fellow believers. That presupposes enough conceptual common ground with those who disagree with him for them to understand his position, controversial though it is, and in principle come to be swayed by his arguments. If Hart can do this, why can’t natural law theorists?

Here we see one of several ways in which Hart’s position is ultimately incoherent. Insofar as he applies his criticisms consistently he will find that they undermine his own view no less than the natural law theorist’s.

Suppose Hume’s stricture against deriving an “ought” from an “is” really were well-founded. It would follow that the purely theological ethics to which Hart seems committed, no less than natural law theory, cannot get off the ground. For statements about what has been divinely revealed, or what God has commanded, would be mere statements of “fact” (as Hume understands facts), statements about what “is” the case. And how (given Hume’s account of practical reason) does that tell us anything about “value,” about what we “ought” to do?

The most we can have are the merely hypothetical imperatives Hart rightly (if inconsistently) derides as insufficient for morality. If we happen to care about what God has said, then we’ll do such-and-such. But that tells us nothing about why we ought to care. Hart, like so many other Christian philosophers and theologians eager to accommodate themselves to Hume and other moderns, fails to see that he has drunk not a tonic that will restore youthfulness to the Faith, but a poison that will kill the modernizer no less than the traditionalist.

Notice also the rich irony of a thinker who urges us to trust in divine revelation rather than natural reason, and who appeals to a secularist philosophical argument in order to make his case. Here Hart recapitulates a muddle that one finds again and again in those who would absorb nature into grace, or otherwise do dirt on mere natural theology and natural law in favor of revelation alone. They inevitably appeal to premises that cannot be found in revelation itself, because there is no way in principle to avoid doing so.

For what is it in the first place for something to be revealed? How can we know it really has been? Why accept this purported revelation rather than that one? If the answers are supposed to be found in some purported revelation itself, how do we know that that was really revealed, or that its meta-level answers are better than those of some other purported revelation? And why wouldn’t such a patently circular procedure—appealing to a purported revelation in order to defend it—justify any point of view? It is only from a point of view outside the revelation—the point of view of our rational nature, which grace can only build on and never replace—that these questions can possibly be answered.

And then there is the question of why anyone else should accept the revelation—the missionary activity that, as I’m sure Hart would agree, the Christian is called to. If you are going to teach an Englishman Goethe in the original, you’re going to have to teach him German first. If you’re going to teach him algebra, you’d better make sure he already knows basic arithmetic. And if you’re going to preach the gospel to him, you’re going to have to convince him first that what you’re saying really did come from God, and isn’t just something the people you got it from made up or hallucinated.

That’s why apologetics—the praeambula fidei, the study of what natural reason can and must know before it can know the truths of faith—precedes dogmatics in the order of knowledge, and always will. The theologian who thinks otherwise is like the Goethe scholar who screams in German at his English-speaking students, telling them what idiots they are—and deriding those who would teach them German as engaged in a “hopeless” task.

Edward Feser is the author of The Last Superstition: A Refutation of the New Atheism  and Aquinas. He blogs about philosophy here.

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