The Return of the Natural Law

Few traditions are as central to Western civilization’s development than natural law philosophy and ethics. Yet, every decade or so, no shortage of modern scholars appear who declare this school of thought, which goes back to Plato and Aristotle and includes minds such as Thomas Aquinas and Moses Maimonides, to be “dead,” “rigid and traditional,” or an “intellectual dinosaur.”

Natural law reasoning, however, always bounces back. One reason for that resilience is that natural law remains the most formidable alternative to consequentialism, utilitarianism, or situation ethics’ various forms that dominate public discourse on topics as different as international relations and bioethics. To varying degrees, these positions hold that it is sometimes acceptable to do things that human beings know, despite their protestations to the contrary, to be evil. For anyone instinctually uneasy with the claim that, for instance, torture might sometimes be good, natural law provides clear explanations for why we do—and should—recoil from such propositions. Another reason for natural law’s persistence is that it represents the alternative to philosophical skepticism, understood as the position that, in the end, we can really know nothing with certainty. An ethics built on principled skepticism is, by definition, constructed on foundations that such a position’s proponents must themselves doubt if they are consistent with their own philosophy’s premises. That is why philosophical skepticism is a self-refuting position.

Natural law’s strength, however, also owes much to the fact that natural law philosophy has always gone through rethinking and refreshment periods. Contra some of its critics, it is not an essentially static intellectual stance. At different points, natural law philosophy has experienced renewal in response to particular challenges and changes, such as the resurgence of particular ideas (i.e., voluntarism in its various guises) or events as momentous as the French Revolution.

Escaping the Legalism of Low Expectations

Another spark for natural law thought’s reinvigoration is that there have been times when some of its proponents have drifted into a type of legalism. You see this in the natural law argumentation often found in Catholic moral theological manuals in the decades immediately before the Second Vatican Council. Their treatment of the connection between virtue and human happiness was often perfunctory. They also reflected a minimalistic mentality of “how far can I go until I cross the moral line?” This uninspiring state of affairs left natural law philosophy ill-equipped to deal with the cultural revolutions that engulfed the world in the late-1960s and from which the West is still trying to save itself.

Some natural law thinkers and moral theologians in the 1970s developed moral theories that retained some of natural law’s language and framework but invested it with consequentialist content in response to these social and political changes. This represented the legalistic mindset’s continuation and its tendency to look for imaginary loopholes that magically turn evil actions into good choices. The same period, however, witnessed the emergence of “new natural law theory” (NNLT), sometimes called “new classical natural law theory.” Initially associated with the theologian Germain Grisez, the philosopher Joseph Boyle, and the legal scholar John Finnis, NNLT has proved immensely influential in shaping Christian ethics along with considerable portions of secular legal and political discourse.

NNLT’s most important expression, John Finnis’s Natural Law and Natural Rights, was published in 1980. Even its critics would, I suggest, concede that this book single-handedly revived natural law as a living force in legal theory. It also helped draw attention to Grisez’s writings that might have otherwise remained obscure.

Since then, NNLT insights have been applied to areas ranging from constitutional questions to economics. But there have also been significant efforts to elaborate on NNLT’s foundations and to make them more immediately apprehensible to audiences unfamiliar with the longstanding ethical and philosophical debates from which NNL emerged. To my mind, a new book, Ethics, Politics, and Natural Law: Principles for Human Flourishing (2025) authored by University of Notre Dame philosophy professor Melissa Moschella, represents the best effort thus far to explain NNLT in terms accessible to general audiences while simultaneously fleshing out some of its political and social implications.

A Personal and Intellectual Journey

Moschella begins by explaining how she made her way to NNLT and why it helped resolve long-standing questions that had puzzled her about the best way to think about morality. This process, she states, took time, partly because she found the “language and approach” of some key NNLT texts to be “off-putting.” This owed something, she observes, to her reading of prominent natural law scholars’ critiques of NNLT who had by no means drifted into consequentialism or become apologists for versions of ethics in which strongly felt feelings trump everything else. What Moschella calls her “philosophical conversion story” led her to see NNLT as “a ‘commonsense’ moral theory:” one that recognized “the intrinsic connection between morality and human flourishing while also accounting for the existence of moral absolutes and the importance of moral character.”

Moschella’s goal is not primarily to provide either NNLT’s academic critics or those still finding their way in the academic philosophy realm with a different account of morality for them to consider. Ethics is not, Moschella stresses, a mere logic game for scholars to play. For her, it is “of vital importance to every human being” for “our flourishing as individuals and communities depends upon whether our choices and actions are in line with moral truth.” For that reason, her book is designed to serve as a resource for non-specialists. She subsequently consigns most of the technical scholarly apparatus and discussion to the footnotes.

The challenge with such an enterprise is that any theory of natural law involves, at some point, some significant unpacking of phraseology like “integral directiveness,” “intermediate moral norms,” “practical reason,” or “a third-order, practical inquiry.” Likewise, terms such as “human flourishing”—precisely because people who attach different meanings to these expressions use them often today—require detailed specification. However, Moschella’s book achieves its stated goal for the most part. Reading this text will immensely benefit those interested in better understanding natural law in general and NNLT in particular.

God, Liberalism, and Patriotism

Moschella’s first two chapters follow seminal NNLT books’ structure in explaining, first, the important NNLT idea of “basic” or “fundamental goods,” and second, the moral principles (what NNLT calls “the first principles of practical reason”) that direct our moral reasoning at the level of ends and means. The third and fourth chapters spell out the implications of NNLT’s account of human flourishing for a variety of social and political issues. Moschella’s last chapter engages with the question that any natural law discussion eventually provokes—i.e., the God question—much as the last chapter of Finnis’s Natural Law and Natural Rights, having explained how natural law per se doesn’t rely upon an a priori acceptance of God’s existence, nevertheless shows how consistent reasoning leads us to understand the superiority of a theistic account of reality and its origins to all alternative explanations. Rather than trying to posit NNTL’s position vis-à-vis all the main religions, Moschella confines her last chapter to the relationship between natural law and Christian Revelation, especially the latter’s conception of the Kingdom of God.

That last point matters because it plays into Moschella’s detailed treatment of two specific questions that merit readers’ close attention. The first concerns what Moschella calls “the Vocation Principle.” Some NNLT scholars have addressed this issue. Nowhere, however, have I found as thorough a treatment as Moschella’s of how the idea of each individual’s unique vocational path (however humble or great it may be) is critical in helping people organize and prioritize their pursuit of the basic goods. This goes a long way to addressing some long-standing objections to NNLT’s idea of the basic goods’ incommensurability.

The second question involves the perpetually vexed relationship between natural law philosophy and liberalism. Many people who identify with one of these camps regard the two as essentially incompatible. That conflict arises from different views of law’s role in shaping morality, arguments about human nature, and endless disputes about what liberalism actually is.

NNLT scholars, however, have made specific contributions to this discussion, most notably through showing how NNLT’s understanding of how we become good through free choice provides principled reasons for putting considerable limits on the state’s efforts to shape people’s moral lives. Much NNLT discussion of this topic, developed primarily by Finnis and Robert P. George, and now further elaborated upon by Moschella, is derived from NNLT’s understanding of the political community’s nature and the common good (“the political common good”) specific to this community. To this discussion, Moschella adds thoughts about the nation and patriotism as a concept. An NNLT conception of patriotism, she maintains, illustrates how governments do have specific responsibilities to their citizens that are not owed to other nations’ citizens while simultaneously demonstrating that patriotism does not support the idea that we have no obligations whatsoever to anyone who does not belong to our nation.

Moschella’s engagement of NNLT with the topics of liberalism and patriotism, as well as her development of the Vocation Principle, are proof-positive of natural law’s remarkable capacity to develop theoretically while also shaping ongoing public debates. But Moschella’s book’s wider significance lies in its potential to introduce people intellectually dissatisfied with skepticism and bored with moral relativism to a tradition of ethical reflection that provides a satisfying account of human free choice and the ends to which reason directs it. As Moschella states, Natural law philosophy may be “commonsense.” Nonetheless, she shows how it is also positively transformative for individuals and political communities who have not given up on the idea that there is moral truth and that we can know it. That is no small thing in a world seemingly paralyzed by perpetual doubt.

Samuel Gregg is the Friedrich Hayek Chair in Economics and Economic History at the American Institute for Economic Research. He is a contributing editor to Civitas Outlook.