Month: September 2025

While routinely invoked by Protestant Reformers during the Reformation, natural law ethics did not have a good twentieth century among Protestant theologians, particularly those in the Reformed (or “Calvinistic”) tradition. Karl Barth famously blasted natural law ethics. Cornelius Van Til blasted both Karl Barth and natural law ethics. More recently, albeit more irenically, Calvin College philosophy Professor James K. A. Smith detailed “What’s Wrong with Natural Law?”

Despite the criticism, or perhaps because of it, the pendulum started swinging back earlier this century. Interest in natural law ethics revived not only among distinctly Reformed and Lutheran scholars, but among Evangelical scholars more generally. This May, Zondervan Academic published Natural Law: Five Views. The book seeks to introduce today’s Protestants to the renewed attention to natural law. To do so, it includes contributions by Catholic as well as Reformed and Lutheran commentators on natural law. It also includes a chapter by one “anti-natural law” theologian.

For the most part, the book’s editors and the four “pro” natural law authors each provide a helpful précis for their particular tradition’s view of natural law. These views are the classical view, the Lutheran view, the Reformed view, and the “new natural law” (a la Germain Grisez, John Finnis, and others).

Each chapter, and the back-and-forth discussion between the contributors that follows each chapter, accomplishes the editors’ and authors’ goal: each contributor provides a brief, chapter-length summary of their tradition’s distinctive emphases and provides sources and citations for the interested reader to follow up.

All that is useful enough. Yet a thought kept nagging me while reading the short volume: The editors and the contributors (except for the “anti-natural law” contributor, of course) seem distinctly interested in promoting “natural law” as a distinctive label or brand name. Pressing the brand name, however, risks muddying waters that the editors and authors aspire to clarify, and losing at least two distinct groups that natural lawyers presumably would count as allies or cobelligerents.

On the one hand, there is a set of scholars and commentators who, like natural lawyers, are moral realists yet who reject or find inadequate some elements of natural law systems. Moral realists hold that moral requirements are objectively true, as opposed to moral requirements being subjective or relative. In the main, all natural lawyers are moral realists, but not all moral realists are natural lawyers.

On the other hand, there are scholars and commentators who actually, if implicitly, apply or draw on forms of natural law methodologies in their arguments, but who want to reject the natural law brand name for one reason or another.

We’ll start with this second set first.

Natural Law in Name vs. Natural Law in Substance

C. S. Lewis, whom the editors and several of the contributors cite with approval, exemplifies brand-name ecumenism in his book, The Abolition of Man.

The thing which I have called for convenience the Tao, and which others may call Natural Law or Traditional Morality or the First Principles of Practical Reason or the First Platitudes, is not one among a series of possible systems of value. It is the sole source of all value judgments. If it is rejected, all value is rejected. … The effort to refute it and raise a new system of value in its place is self-contradictory.

What is critical in Lewis’s view is not whether one applies the “natural law” label to one’s view, but the substantive commitment to moral realism, whatever one terms it.

Lewis, for example, would welcome Ronald Dworkin’s echo of the “reductio” Lewis asserts in The Abolition of Man regarding the self-refuting nature of moral skepticism. In his book Law’s Empire, Dworkin writes that if a person “really believes, in an internally skeptical way, that no moral judgment is really better than any other, he cannot then add that in his opinion slavery is unjust.” This is a form of the “reductio” that Lewis employs, even if the affirmative content of the objective morality each asserts ultimately differs at signal points.

Yet while Dworkin devoted much of his career to arguing that morality cannot be separated from law, he nonetheless resisted the claim that his theory reflected some version of natural law theory. He did so not because it wasn’t true, but rather because he didn’t deem it “a very important objection.” He observed that labeling his theory a natural law theory merely “suggests a different way of reporting” what his theory is about.

Or consider Michigan Law Professor Scott Hershovitz, who argues a different version of Dworkin’s thesis in his recent book, Law Is a Moral Practice. Hershovitz, too, does not deny that he engages in natural-law reasoning. Rather, he rejects the label as just not “helpful” in identifying the nature of his argument, given the wide variation in theories that go under the label.

Whether they are moral realists who reject the natural law label or moral realists who accept the natural law label, it seems that in this day and age the wedge issue is moral realism versus the rejection of moral realism.

To be sure, natural law jurisprudence should not be identified with natural law ethics, but the two sets of literature do intersect. Both Dworkin and Hershovitz advance a form of moral realism in their arguments, although neither thought it necessary to anchor their moral realism in a deeper metaphysical system. (Dworkin, for instance, did not believe in God.)

On the other hand, the “anti-natural law” contributor to the “Five Views” volume, Peter Leithart (with whom I co-edited a book), argues that “natural law” does not apply to his thought because he believes it necessary to posit a deeper metaphysical system of thought to account for knowledge of law, and this requires divine rather than natural revelation. (More on this point below.) Despite rejecting the natural law label in application to his view, the volume’s editors wonder whether Leithart is “truly ‘Anti-Natural Law.’”

It seems to me that many who reject the natural law label nonetheless either apply a natural law methodology or assert a form of moral realism that rejects moral relativism, an outcome the editors of the Five Views book suggest is realized uniquely by natural law theories.

Natural Law Methodologies vs. the Natural Law Brand Name

The irony is that many scholars and commentators who ignore or reject the natural law label nonetheless employ one or another form of natural law methodology. The question then is whether it is worth the effort to persuade these scholars to apply the brand name to their product. This, as opposed to the possibility that self-identified natural law aficionados can, like C. S. Lewis, simply declare victory and focus on the substantive debate over the content of natural law principles.

To make this argument, we first need to identify what are “natural law” methodologies. Here, the heterogeneity of natural law theories can be a problem. I suspect that some scholars reject the natural law label because they think it requires a commitment to a methodology they do not employ or to which they object. Without any claim to exhaustiveness, and with the proviso that methodologies can overlap, I would generally follow Russell Kirk, with some differences by way of emphasis, and count at least four basic types of natural law methodologies:

• Connaturalism and/or an intuitive commitment to some form of moral realism as self-evident (cf., Aquinas, ST I-II. q. 91, a3).
• Principles and actions that promote achieving the human teleology, that is, achieving the human end or “nature” in the Aristotelian sense (see, for example, Aristotle’s Politics I.2, 1252b30-34 or Nichomachean Ethics I.7, 1097b24-29).
• Rejection of self-refuting propositions. (See, for example, John Finnis; Aquinas, ST I-II. q. 94, a2).
• Empirically observed universal, or near-universal human beliefs and/or behavior. (See, for example, Edward O. Wilson’s empirical/biological argument, or Aquinas, ST I-II. q. 94, a3, ad.2, or Lewis’s argument in The Abolition of Man.)

As I mentioned, these types can overlap. For example, Finnis’s argument in Natural Law and Natural Rights asserts both that the “basic goods” he identifies are “self-evident” and asserts the claim that to reject any of the basic goods he identifies is self-refuting.

The larger point of the exercise, however, is that any number of commentators who reject the label “natural law” nonetheless implicitly employ natural law methodologies. Dworkin and Hershovitz, for example, seem to employ a form of moral intuitionism.

The question is how much energy natural law advocates want or need to invest in persuading these folk expressly to apply a natural law nomenclature to their work versus the alternative that C. S. Lewis modeled, of simply recognizing that those who are not against us are for us, and focus attention and resources on substantive questions.

Anyone who reasons from a human telos, an image of human flourishing, implicitly engages in a natural law methodology even though the content or conclusions of their theory may diverge.

Consider the difference between Aristotle’s and Aquinas’s teleologies. Both Aristotle and Aquinas conceive of a human nature through what it means for a human to be wholly mature or fully flourishing. But Aristotle identifies flourishing with “an activity of the soul in accord with virtue,” while Aquinas identifies it with realizing the beatific vision. To be sure, there can be overlap between these two views, perhaps substantial overlap. But they are not necessarily the same thing.

The point of observing this is to note that anyone who reasons from a human telos, an image of human flourishing, implicitly engages in this sort of natural law methodology, even though the content or conclusions of their natural law theory will diverge depending on the distinctive telos they reason from.

Whether the image of human flourishing is that of Maslow’s hierarchy of needs, the freedom of the Jeffersonian yeoman, or overcoming Karl Marx’s alienation, all posit a telos that can be understood to identify a human “nature” to which the Aristotelian methodology can apply.

I want to emphasize that I am not suggesting that it doesn’t matter what we posit as the human telos or our view of human flourishing. It matters critically; analysts will argue over which image of human flourishing is correct or appropriate.

The point is that deriving moral or political implications from a concept of human flourishing—any concept of human flourishing—is a natural law methodology, whether one calls it that or not. That Aristotle and Aquinas (or others) disagree about the ultimate nature of the human telos does not mean that one or the other is therefore not engaging in natural law reasoning. Nonetheless, the promiscuity of natural law theory here is one reason scholars such as Hershovitz don’t think it’s helpful to be identified with natural law.

So, too, for example, Dworkin and other secular scholars. Despite not believing in God, Dworkin nonetheless embraced a form of moral intuitionism that required him to posit a form of moral realism. Pertinent to the Five Views book, this moral realism—the belief that moral principles were objective and could be known and applied—would seem to be consistent with the minimal threshold that the Apostle Paul identifies for non-believers reflecting the requirements of the law “by nature” in his letter to the Romans, a canonical text for natural law (Romans 2:14-15).

Even the likes of nineteenth-century legal positivist scholar John Austin, who expressly warred against the notion of “natural law” in jurisprudence (calling it “stark nonsense”), was nonetheless a moral realist. Austin assented “without hesitation” to the view that “all human laws ought to conform to the Divine laws.” He agreed that “if human commands conflict with the Divine law,” then the human law should be “disobey[ed]” in favor of the Divine law. While insisting that “law” can be identified by positive attributes alone—he insisted that “the existence of law is one thing; its merit or demerit is another”—Austin was nonetheless a moral realist.

Sin and the Problem of Gaps in Apprehension of Natural Law

The Protestant theologians who criticize natural law are moral realists as well. In the main, they object to the notion that natural law is accessible to reason on account that sin impacts humans so dramatically that it can limit natural knowledge of morality in significant ways. This creates a very practical problem for an argument commonly deployed to argue for natural law. The argument is that “natural law” is moral knowledge shared generically by humanity across culture and across time. In response, some Protestant theologians have argued that if sin so dramatically affects moral knowledge that there are gaps in the human conscience at particular times and cultures, then natural law cannot or does not provide a universally accessible moral system.

Many who reject the natural law label nonetheless either apply a natural law methodology or assert a form of moral realism that rejects moral relativism.

The issue revolves around whether sin affects the moral conscience so significantly that natural law fails to meet the threshold for robust versions of moral responsibility.

While Aquinas is often forwarded as a paradigmatic natural lawyer, it seems to me that he goes further down this anti-natural law road than is often conceded. Divine law, which is biblically revealed law for Aquinas, is needed not only for matters beyond what is accessible to reason (Aquinas includes the Gospel in this category), but also for matters that are accessible to reason but to which access has been “impeded” by sin. Aquinas writes:

It was fitting that the Divine law should come to man’s assistance not only in those things for which reason is insufficient, but also in those things in which human reason may happen to be impeded. … Through being habituated to sin, [human reason] became obscured in the point of things to be done in detail. … The reason of many men went astray to the extent to judging to be lawful things that are evil in themselves. Hence there was need for the authority of the Divine law to rescue man from both of these defects (ST I-II. Q. 99, A.2).

The issue here pertains to the robustness of natural law, that is, the problem of gaps in apprehension of natural law.

Note first that, for Aquinas, this is not a minor problem for humanity. Aquinas observes that being “habituated to sin” is the “reason … many men went astray” in approving evil things.

Secondly, in referring to moral sense being “obscured … in detail,” Aquinas means that the natural law becomes obscured on specific moral points, but these can be significant moral points. One example of impeded human reason that Aquinas discusses is German barbarians for whom “theft, although it is expressly contrary to the natural law, was not considered wrong” (ST I-II. Q.94, A.4). So, too,

the natural law can be blotted out from the human heart, either by evil persuasions, just as in speculative matters errors occur in respect of necessary conclusions; or by vicious customs and corrupt habits, as among some men, theft, and even unnatural vices, as the Apostle states (Rom. 1), were not esteemed sinful. (ST I-II. Q.94, A.6).

Let’s take Aquinas’s example of theft and consider how this would create a very practical problem for the deployment of natural law in concrete situations. Let’s say that the moral conscience is working just fine for nine of the Ten Commandments. But the consciences of “many men” in our society have gone astray on the natural law behind one commandment, the commandment against theft. The practical problem is that it is specifically when there’s a failure to follow the law that we would want to appeal to conscience to persuade people to stop stealing. But it’s precisely on the point of theft (in my hypothetical) that the appeal to conscience wouldn’t work because reasoning has been impeded regarding this principle.

The natural lawyers’ habitually appeal to Romans 2:14, when Paul discusses that “Gentiles who do not have doing by nature the things of Law,” doesn’t help at this point. This canonical text for Christian natural lawyers contains an opening conditional (a condition that is often elided over). Paul writes, “For when Gentiles who do not have the Law do by nature the things of the Law.” Paul’s argument here does not require that Gentiles by nature recognize all the things stipulated in the Law. His argument is only that “when” they do, their conscience bears witness to the Law.

Paul’s argument is consistent with the possibility of gaps in apprehension of natural law. Take the Ten Commandments again, and Aquinas’s example of ancient German barbarians thinking that theft is morally permissible. As long as their conscience “accuses” them regarding one of the other nine commandments, then Paul’s argument is satisfied. Their consciences “accuse them” on one or more of these other grounds, and, therefore, they know they have sinned (which is the bigger point that Paul is making in the passage).

The problem that “gaps” create for natural law systems is that natural law cannot be offered as a theory that accounts for a universal morality accessible to all people … except when it doesn’t.

Whether they are moral realists who reject the natural law label or moral realists who accept the natural law label, it seems that in this day and age, the wedge issue is moral realism versus the rejection of moral realism. As C. S. Lewis suggests, it doesn’t matter all that much what label we apply to the view as long as it’s some form of moral realism. I’m not suggesting that advocates of one view or the other shouldn’t burn any of their free time arguing over whether Coke is better than Pepsi or vice versa. At the same time, we don’t want to get caught up in a form of natural-law sectarianism akin to what Emo Philps lampooned with his telling “die heretic” joke.