At its inception in seventeenth-century England, our liberal order held that law must be humble. Brutal political conflict had proved that we are incapable of knowing basic moral and social truths. With fundamental disagreement inescapable, law must defer to skepticism and relativism. Humble law would provide just enough stability to leave people free to safely craft their own truths, identities, and manners of life. In the framing of Sean Coyle, since liberalism doubts that there are “any true principles of right conduct that are rationally discoverable,” the ambition of natural law jurisprudence to codify universally known moral truths smacks of vain authoritarianism.

　　Natural law is at odds with the liberal spirit that established our law schools and, laments Sean Coyle, “has contributed to the dismissal of natural law theory as an antiquated relic of no relevance to modern times.” Even though natural law theory dominated Western legal education from the twelfth through to the end of the eighteenth century, academic publishing today seldom features natural law in its handbooks of law and legal theory.

　　Professor of Jurisprudence at the University of Birmingham, England, Coyles book Natural Law and Modern Society is a large and detailed inquiry into the resilience, cogency, and scope of natural law theory. A rich and careful work, Coyle’s is a technical study in the philosophy of law. Coming in three parts, Natural Law and Modern Society first shows that natural law theory bests legal positivism, the principal theory of law in higher education today. The second section shows the cogency of tying morality to legal justice, and the third demonstrates the range of natural law in adjudicating knotty jurisprudential questions, such as whether natural rights are the same as human rights.

　　Throughout, the natural law tradition is represented by the Catholic Italian friar Thomas Aquinas (c. 1225–74), the Spanish Jesuit Francisco Suarez (1548–1617), and the Dutch Protestant Hugo Grotius (1583–1645). By no means are these theorists identical and Coyle sometimes plays one off against another. However, they represent, he believes, a tradition of powerful and live jurisprudential concepts.

　　No Escape

　　Most law school education is built on a foundationof legal positivism. Legal positivists argue that the effort by natural law thinkers to lodge law in morals is both fruitless and pernicious: our knowledge is too limited, and the attempt must make a casualty of tolerance. Coyle counters that classic works of legal positivism show there is no escape from natural law reasoning.

　　Natural law jurisprudence dates to Aquinas, but asCoyle points out,Thomas relies on a eudaemonist philosophy built upon the ancients and their idea that persons ultimately act for “the end for the sake of which all other ends are sought (in Aristotle’s definition), or as the good composed of all other goods (as in Plato’s).” Combining and amending Aristotle and Plato, Aquinas posits that the end is the loving personal Logos. As Aquinas explains, this makes the cosmos a rational community: “The whole community of the universe is governed by Divine Reason.” Human nature, says Aquinas, “has a share of the Eternal Reason, whereby it has a natural inclination to its proper act and end.” By contrast, and typical of modern deflationary accounts of meaning and reality, legal positivism atomizes, resting its defence of liberty, as Coyle puts it, on the “belief that each person invents their own end.”

　　Natural law, relays Coyle, relies on the proposition that “reason does not impose order upon human nature but discovers an order that is already present.” Per this order, natural law reflection identifies a pattern of human goods without which persons cannot flourish. Natural law theory proves its resilience because legal positivism backs into these human goods.

　　Coyle ably shows that prominent legal positivists assume such natural goods. They cannot explain legal phenomena otherwise. For example, the Austrian Hans Kelsen (1881–1973) reasons that violators of the law are punished with a “depravation of possessions—life, health, freedom or property.” It is quite clear that these are the human goods of eudaemonist reasoning. The English H. L. A. Hart fares no better. Certainly alert to the problem, he argues that the end of human striving is survival. However, he proposes that “all living are described as healthy or unhealthy depending upon their progress towards or away from their optimal condition.” Hart speaks of human vulnerability, for example, but one is then compelled to ask what is the character of woundedness? The only possible answer is that human goods are lost in our being wounded. Coyle insists: “This signals his agreement with Aristotle that the nature of a thing is determined according to a mature and flourishing condition of a thing, not the condition in which it is merely in potentia or in decay.”

　　What then are the basics of this theory of “objective human ends”?

　　Core Morality

　　The natural law tradition argues that human beings are always set insidean order of desires. Coyle quotes Aquinas: “The natural law is promulgated precisely in that God instilled it in us, in the form of natural knowledge [i.e. inclinations].” The addition in brackets is made by Coyle. Rightly, I think, he takes Aquinas to argue that our inclinations are a natural knowledge of morals. That is, they make evident to us human goods. An illustration of the cogency of this idea is Adam Smith’s plausible belief that language had its origin in the human need to settle on words for housing, clothing, and nourishment.

　　This natural knowledge of the good is refined by our rational nature into precepts of law. The inclinations shine a light on objects that are good for us and in this light reason frames, Coyle explains, “the relevant range of precepts of natural law [that] include being at peace with others, creation of and participation in mutual forbearances, defence of the weak against the violence of the strong, suppression of criminality, and so forth.”

　　This work of rational desire is “the law’s rationality,” argues the natural law tradition. Coyle observes something more: “But Aquinas in fact sets out a hierarchy among the primary precepts of natural law, ranging from the most fundamental (protection of life) to those which call out to human excellences (sociability, peace, intellectual relationship to God).” This helps explain why liberalism is averse to the core morality idea of natural law theory. Even if liberal theory could concede we have a natural moral orientation set by desire, the idea that desire shapes up in a hierarchical order cannot be borne. It is for this reason that Hobbes pointedly minimizes our appetites to violent self-interest.

　　Natural law theory defends the idea of a core morality, but it also gives great latitude to lawmakers in crafting reason-based laws.

　　Aquinas says that “natural law is something appointed by reason” and Coyle is quick to observe that “the demands of natural law are immanent demands.” For this reason, Coyle argues that natural law jurisprudence is not a branch of philosophical theology, and nor is it a branch of political theory. Core morality is not up for political negotiation. It is the measure by which one can assess the justice of human-made law (positive law). In a nice formulation, Coyle drives home the point that per natural law, “ethics is the starting point for all inquiry into law and politics: the human goods that the law protects must first be identified and illuminated.”

　　We can only attain the ends to which we are prompted by our inclinations by having “the good of a stable legal order.” This brings us to the tricky problem of the common good. “For certain general aspects of common good are an intrinsic part of the individual’s good.” An example is due process. What institutional order expresses this common good?

　　Human Rights

　　Following Aquinas, Coyle argues that law must be directed to the common good, lest it becomea mere façade of law. The common good is neither the utilitarian idea of the “greater number” nor an organicist lockstep but a social friendship that secures “the benefit of the whole community including the individual.” It assumes establishment. Coyle cites Suarez’s interesting examples of open meadows, churches, and magistracies composing establishment. We can add much to the list, but the important point is that establishment is an enabling communal background, “the whole edifice of rules and conditions that make individual choice possible.”

　　Natural law “establishment” is necessarily a complex phenomenon, sincethe common good has elements of bothexternal and internal peace. Bothinternational law and criminal law would be included in the larger phenomenon. Our sociability demands concord amongst citizens, and so natural law establishment also includes contract and administrative law, monitoring prosperity and just distribution. As a measure of the order of desire, natural law is of wide scope;its jurisprudence frames all the principal areas of law. However, not all elements of our legal establishment are equally rooted in reason. An example is the difference in standing between natural and human rights.

　　A quiet partner in this book is Catholic Social Thought (CST), that body of moral and legal reflection primarily developed by popes. The Catholic Church is the global institution that frames its public discourse—addressed to “all people of good will”—in terms of natural law theory. Papal documents speak liberally of human rights, but during the pontificate of St. John Paul II, epic diplomatic battles raged as the Clinton administration sought towrite into UN documents abortion as a human right—an issue still very much with us. What continuity is there between core morality and human rights?

　　Coyle is fond of a phrase fromGaudium et spes. This 1965 Vatican II document warns that there are “forgotten and unacknowledged rights” belonging to the poor and needy. Human rights are positive law, written into treaty documents by Commissioners—in the first place by Eleanor Roosevelt. In 1948, the philosophical foundation of the new category of rights was said to be work for another day. Insofar as human rights are linked to our being, and not mere historical creations, they are in fact natural rights, contends Coyle. For example, the human right of family is based upon the natural right of parents to be stewards of their children, and evidence of the natural heft of that right is the high burden placed on the state before lawful child removal.

　　Positive law is a welcome and necessary part of legal establishment. However, the measure of human-made law is “the law’s rationality,” the work of rational desire. Being alert to this measure is basic to the work of jurists and policymakers lest they transgress natural justice. A too-casual orchestration of human rights is likely to trammel the poor and needy, who are not represented in the corridors of power where human rights documents are drafted. Alertness to the institutional character of legal establishment is critical if we are to heed the warning of St. Augustine’s libido dominandi or Adam Smith’s “conspiracy of the merchants.” Indeed, Coyle flags the “ideology of human rights,” cautioning that human rights proliferation is the work of a caste, the global legal literati. It is part of the scope of natural law to monitor the drafting of laws by the state and its analogs.

　　Growing Relevance

　　Natural Law and Modern Society is 450 pages of close argumentation. The argumentation will be recognizable to those familiar with the analytical tradition of philosophy. It makes a good companion piece to James Carey’s Natural Reason and Natural Law,a fine work placing Thomas alongside Strauss and Heidegger. Sadly, this volume is a shocking price ($145). I do not know why. The pages are not sewn but glued. Other academic presses put out hardbacks with even more pages for $35.

　　Besides resilience, cogency, and scope, natural law’s theoretical relevance is more obvious with our changing world order. Natural law theory defends the idea of a core morality, but it also gives great latitude to lawmakers in crafting reason-based laws. It is ideally positioned to articulate and justifya universal but limited set of objective moral truths to which all legal systems must defer, while also tolerating not only varied laws and procedures, but various political regimes. Natural law takes the liberty of human law seriously. For this reason, legal orders informed by natural law jurisprudence have always been humble. With world order becoming polycentric natural law theory stands fair to see a revival.