The Early Example of Emil Brunner

Let us start with the integrative Christian theory of marriage of early twentieth‐century Swiss theologian, Emil Brunner. Brunner was a theologian working out of the Reformed or Calvinist tradition. He taught in Switzerland during and after the seismic cultural convulsions of World War II. He serves as a late modern exemplar of both the Protestant use of covenant theology and the Catholic use of natural law, a combination that can be found in earlier Protestant sources such as John Calvin, Johannes Althusius, and John Milton (Witte 2007).

Brunner starts his theology of the spheres of society by distinguishing three kinds of human interests stemming from what he calls the “psychophysical nature” of human beings. They are the human needs for (1) sex, intimacy, and offspring; (2) acquisition and economic well‐being; and (3) safety and control over the contingencies of life. In Brunner's view, these interests are fostered and fulfilled by different spheres of society: sex and procreation by marriage and the family; acquisition and economic well‐being by labor and the market; and safety and control by the state and its laws. These three kinds of human interests are “premoral”—that is, they are morally relevant but not morally definitive. Brunner believed that these interests, and the respective spheres of society that satisfy and normatively organize them, can be known and analyzed by human reason (Brunner 1957, 335). These interests, the goods toward which they are oriented, and the reason that identifies them all together constitute, according to Brunner, the baseline of natural law. In acknowledging this, he was siding with those branches of Protestantism that retained some appreciation for the classical and Christian natural law tradition.

By taking this step, however, Brunner also came into conflict with the more strictly revelational or divine command way of grounding normative human institutions and practices—including marriage—found in the work of his immensely influential contemporary Reformed theologian, Karl Barth. In fact, their disagreements led to a famous debate between them about natural law, natural theology, and natural rights. Brunner was a theologian who took seriously the commands and covenants of God and tended, as did Barth, to see them less as prohibitions and more as liberating permissions, promises, and gifts of love (Brunner & Barth 2002). Brunner believed that, from a Christian perspective, each of these three spheres of society should be guided by covenant faithfulness to God, even though each also gains some normative content from one of the respective needs or interests apprehended by reason. Brunner saw these divinely inspired and liberating commands, gifts, permissions, and covenants as guiding and fulfilling the natural God‐given sexual, acquisitive, and security interests of humans.

Brunner held that these three forms of communal life could be understood in certain ways independently of faith. He wrote: “These forms of community … are all independent of faith, and of the love which flows from faith.” But then he continued: “This does not mean that their significance and their true nature can be rightly known outside the sphere of faith.” These natural impulses toward the different spheres of communal life “conceal within themselves the Divine orders of creation”—God's intention for the future fulfillment of all humans. Furthermore, these natural forms of community constitute something like divine training schools for higher and more fulfilling forms of life that God wills in creation. Brunner believed that, from the perspective of human reason, these spheres function to articulate and meet human needs; from the perspective of faith, they are gifts of God inspite of the fact that they are changing, broken, and sinful (Brunner & Barth 2002, 333–37).

Karl Barth believed that Brunner had sold out to an inadequate Roman Catholic theory of natural law. Barth called Brunner's idea of orders of creation a “horizontal” ethic that had lost contact with a transcendent revelation. He once said this about Brunner's formulation: “But we cannot help feeling that at the root of his conception of ‘order’ there lies something akin to the familiar notion of lex naturae which is immanent in reality and inscribed upon the heart of man, so that it is directly known to him.” (Barth 1961, III/4, 20)

Barth, I am convinced, was wrong in his interpretation of Brunner. Brunner says that reason can discern the human interests motivating the spheres or orders of creation, including the order of family and marriage. But he also believed that human reason alone cannot fully normatively define and properly actualize these interests. As a Christian theologian, Brunner was not functioning as a philosophical foundationalist in asserting that reason can grasp knowledge of these interests and spheres. That is, he was not first emptying his mind of the witness of the Christian tradition and then using reason to build up, from some empirical or rational ground floor, the normative role of marital monogamy in a one‐flesh union of father, mother, and child. Rather, he was using reason in a “distanciated” way, as we will soon see that Paul Ricoeur does in his critical hermeneutics (Ricoeur 1981, 59–62). Reason may be able to gain a certain degree of “distance,” in contrast to pure objectivity, from its shaping by a normative tradition. Because of this, it may thereby discern some of the rhythms of our natural human sexuality and other natural needs that then anticipate and incline us toward covenanted life‐long monogamy. Furthermore, forms of “distanciated” social‐scientific reason and empirical observation may help us see the beneficial consequences—the goods, so to speak—that flow from this covenantal relation.

On the issue of marriage, Brunner occupies a conceptual space somewhere between Thomas Aquinas on the Catholic side and Karl Barth on the Protestant side. The natural interests of sex and procreation (especially when the factor of long‐term human infant dependency is added) anticipate and are fulfilled in the monogamous relation between husband and wife willed by God in creation. Yes, Brunner, as did Aquinas, acknowledged that there are natural polygamous impulses in humans, especially men. Yes, there is the reality of infidelity and divorce. But there is also an inclination toward monogamy in the very nature of human sexuality and procreation, as ambiguous and easily disrupted as it may be.

Brunner emphasized the importance of parental recognition for the rise of monogamy—tracking the arguments of Aquinas and others, and anticipating today's evolutionary psychologists in so doing. This is the parent's recognition that this child is mine, someone I brought into the world, and indeed someone who is literally part of my very being (Browning, Miller‐McLemore, Couture, Lyon, & Franklin 2000, 113–24). But Brunner conceived this recognition as a three‐way recognition, a point very important, in my view. It entailed a mutual recognition between father, mother, and child. Historical natural law theorists and modern evolutionary scientists both agree that the mother's recognition that the child is hers comes more easily than the father's; the father's recognition of this fact is more contingent, situational, and a matter of probability. But they also agree that most human males recognize and care for their offspring more often than other mammalian males do, which says much about what is unique about the human species.

Brunner added something, however, that is often left out of public discourse today—especially in a time when anonymous donor fathers and transient sexual relationships have left a growing number of children who do not know who their parents of conception actually are (Marquardt, Glenn, & Clarke 2010). Brunner highlights the importance of the child's recognition that this woman and this man are responsible for my existence. These two people brought me, as a child, into the world and I, the child know this, or may someday learn it, or at minimum be capable of recognizing this; knowing this truth is not just a right and capacity enjoyed by the parents. It is a capacity and therefore a right of the child. The trinity of recognitions of this bio‐existential reality throws mother, father, and child together in irrevocable ways. Brunner writes:

Since I, the father, as well as the mother and the child, know irrevocably that this fact is irrevocable, then we three persons are bound together in a way in which no other three persons have ever been bound together, in an unparalleled and indissoluble relation… . This trinity of being we call the human structure of existence. (Brunner 1957, 346)

This structure of existence is uniquely human not only because it is a biological reality but also because it is known—recognized—to be so by all three members of the one‐flesh union.

In short, Brunner believes that nature itself at the human level both anticipates and is completed by God's intention as revealed in creation that husband, wife, and child become “one flesh.” Jesus himself, in his commentary on Genesis 2:24, advances the idea that this one‐flesh union should be lifelong. Remember the words recorded in Matthew 19:6 (NRSV): “So they are no longer two, but one flesh. Therefore what God has joined together, let no one separate.” We do not need to harden these strictures into a totalistic antidivorce stance to realize that this passage is the culmination of the Christian ideal of marriage as revealed in the story of creation and affirmed by Jesus at the beginning of his ministry.

Brunner acknowledges that there is a fourth social sphere besides the family, market, and state—the sphere of religion, which for him is mainly exemplified by the church in both its empirical and ideal forms. The sphere of the church, from his perspective, is not directly derived from a psychophysical interest but addresses, helps guide, and tries to realize the true and integrated purposes of the other three basic interests. From Brunner's Reformed theological perspective, each of these spheres deserves a high degree of autonomy from the other spheres in pursuing its unique functions, developing its logics, and refining its specific strategies. On the other hand, from a theological perspective, each of these spheres should complete its moral goals within the structure of God's covenantal fidelity, gifts, and demands. According to Brunner, religion in general and Christianity in particular has much to do with promoting the true ends of the various spheres of society and the human interests they serve, not through direct command and control, but through moral and spiritual influence (Brunner 1957, 552–54).

Brunner, echoing in part the Dutch theologian and statesmen, Abraham Kuyper, believed that the social spheres should respect each other's special functions, resist interfering and undermining other spheres, yet also support the other spheres of society in accomplishing their unique goals. As Kuyper phrased it: each social sphere has its own “sovereignty” (Witte 2007, 321–30). For instance, the market should help the family supply its economic needs, but should not disturb or distort the family's intimacy, or its procreative and nurturance goals. Government should not own or completely control either family or market even though it should assist each to fulfill its special tasks. The church should not directly control family, market, or government although it should remind them of their higher moral, social, and covenantal obligations. The technical rationality and structural differentiation characteristic of modern societies are challenges to social theories holding that it is a major task of religion to help social spheres maintain their unique goals without undermining them in the process. This is why in such societies any moral or legal theory urging an integrated view of marriage and family must be as multidimensional as possible (Browning 2003).

Roman Catholic subsidiarity theory has a different way of talking about much the same vision of society that we find in Protestant covenantal thinkers like Brunner and Kuyper. The Roman Catholic Church advanced this theory at the turn of the twentieth century when the legal and social control of society by the church had been long gone but threatened to be replaced by either the socialist state or the capitalist market. Roman Catholic subsidiarity theory, informed as it was by Aristotelian and Thomistic theories of the importance of the premoral goods of the natural family and kin altruism, was designed to keep both government and market from controlling and thereby undermining the integrity of the increasingly embattled domestic sphere. The doctrine of “subsidiarity” insisted that neither the market (through excessive work demands and commercialization) nor the state (through its paternalism and control) should undermine the marriage‐based family nor undercut the church's special protection and nurturance of this institution (Hittinger 2003). In both Protestant and Catholic formulations, the state and market had specialized functions, but they had to constrain themselves and cooperate in preserving and enhancing a pluralistic society. Much of this Brunner absorbed and distilled in his understanding of the place of the family in church, state, market, and society.

Premoral Goods and the Natural Law Configuration of Marriage

Part of what attracts me to Brunner's work is that he offers a sophisticated theory of natural law rooted in a sophisticated theory of the premoral goods of life. A covenant theory of marriage and society that uses natural law needs a theory of premoral goods as well, and Brunner's work further illustrates that. His theory of marriage has three layers of argument—an understanding of premoral goods or interests that humans have, a theory of natural law that inclines humans toward certain sexual, marital, and familial habits that are naturally expedient, and a theory of covenant that stabilizes and organizes these natural inclinations for the good of each person and the common good of society.

The starting point for a natural law theory of marriage, I have said, is a theory of the premoral good. It is now time to make this claim in more detail. When moral philosophy and theology use the concepts of premoral or nonmoral goods, they are speaking of the countless ways we refer to the various goods of life that are not directly moral goods. I follow positions on the nature of premoral good found in the neo‐Thomistic moral theologian Louis Janssens and the nearly identical concept of the nonmoral good developed by the distinguished American moral philosopher William Frankena (Browning 2006, 190–220).

Here's how the concept works. If someone says “this water is good,” she is not saying it is morally good. She is making a premoral judgment; she is saying it is clean, has a nice refreshing taste, and is likely healthy to drink. If she is a mother interested in her children's health and then claims that the mayor and the commissioner of sanitation should provide clean water for her offspring, she is making a moral judgment. And if she says that these authorities should provide clean water equally for everyone—not just the elite, the wealthy, or not even just for her own family—she is making a moral statement about justice or fairness. But notice, although water is not directly a moral good, it is a premoral good. People never know what moral statements about justice actually mean unless they know that these statements are about the distribution of something premorally good for human beings—something like water, but which is itself not directly a moral good. Water does not have a will and cannot itself act, either morally or immorally. We never say, “Water is moral.” But we do say that “Mary is a moral person.”

The distinction between premoral and fully moral judgments runs throughout our everyday moral and legal discourse whether we are talking about water or whether we are talking about Brunner's psychophysical goods of sex and procreation, economic well‐being, or security and order. Even Brunner's three psychophysical interests or goods are not moral goods because it is entirely possible to pursue and attain them in totally ruthless and immoral ways. In fact, in covenant theology, it was precisely the purpose of the covenant organization of the spheres of family, market, and state to bring moral order to the pursuit of these premoral interests or goods. Arriving at an analysis of the reality and centrality of these goods and interests was, according to Brunner, the function of natural law. It was the task of covenant and its overall narrative about the purposes of life to give moral organization to these interests both internally to specific persons and externally in relation to the spheres of society.

The Western tradition has long had a sophisticated theory of the premoral goods of human sexuality, pairing, and reproduction, which it wove into what I call the “natural law configuration” of marriage—the steady and thickening line of arguments about the necessary natural connections between sex, marriage, family, and children. This argument, started with Aristotle and the later Plato, proceeded through the Stoics and various Church Fathers, got expanded by Aquinas and the medieval canonists, was embroidered by the Protestant Reformers and Spanish Counterreformers, was cast in increasingly secular natural law terms by Enlightenment philosophers in England, France, America, and Scotland, and from there was woven deeply into Anglo‐American family law (Browning & Witte forthcoming, chaps. 3–9). I think that much of this natural law argument about sex, marriage, and family life is still pertinent and useful today.

As traditionally formulated, this natural law argument starts with the premoral reality that most humans are social creatures; that they have sexual capacities and desires; that they reproduce by sexual pairing; that their children are born fragile and helpless and utterly dependent on their parents for many years; and that natural ties between humans both induce them to help each other but repel them from sex with each other. These are simple facts and natural realities about human sexuality, reproduction, development, and bonding—neither moral nor immoral, but premoral.

Natural law theorists over the centuries have woven these premoral goods into an argument about how and why humans are naturally inclined to center, if not confine, their sexual and procreational activities within marriage. The heart of the argument is that exclusive and enduring monogamous marriages are the best way to ensure paternal certainty and thus joint parental investment in dependent children. If men and women could have random sex with anyone, men would not only exploit women mercilessly to gratify their sexual drives, but they would also ignore their children, since they would have no certainty of their paternity. If men did not invest in the care of their children, many of those children would suffer or die, particularly as infants, when their mothers were weakened from childbirth and lack of sleep and least capable of carrying for all her children and herself as well. Thus, the natural law inclines rational humans to center if not confine their sex to marriage for the long‐term good of their children and of the human species, even though humans still have perennial and sometimes indiscriminate sexual urges. The natural law further inclines a mother to bond deeply with her child during pregnancy and nursing and to nourish and protect it until it has grown. And the natural law inclines fathers to attach to a child that he knows is his own, that looks like him, that is an extension and creation of his being or substance, and that can carry on his name, work, property, and legacy.

Exclusive and enduring monogamous marriages, furthermore, are the best way to ensure that men and women are treated with equal dignity and respect, and that husbands and wives, parents and children provide each other with mutual support and protection throughout their lifetimes. If husbands could just walk away from their wives once they have produced children, if wives could just walk away from their husbands if they became injured or impotent, if children could just abandon their families once they had been emancipated from their childhood homes, or if parents could ignore their emancipated children even when they have great need, too many parties would be left vulnerable and dependent on the charity of others. The natural law thus inclines humans to remain bonded to their marriages and families, and to care for their natural kin throughout their lives, even at ample personal sacrifice.

This argument presupposes that husbands and wives work hard to remain in open and active communication with each other, and especially that they maintain active and healthy sex lives—even when, indeed especially when, procreation is not or is no longer possible. Robust sexual communication within marriage is essential for couples to deepen their marital love and to keep them in their own beds, rather than testing their neighbor's. And marital sex sometimes is even more important when the marital home is (newly) empty, and husbands and wives depend more centrally on each other (not on their children) for emotional confirmation and fulfillment.

This natural law configuration of marriage drew on complex and evolving ideas concerning human infant dependency, parental bonding, parental certainty, paternal investment, kin altruism, incest revulsion, exogamous (nonincestuous) marriage, and the natural rights and duties of husband and wives, parents and children. But, particularly in its early modern and modern formulations, the argument started with two basic brute realities that every moral and legal system of sex, marriage, and family life must address: that human children need concerted help from their parents for a very long time and that human adults crave regular sex with another a good deal of the time.

Rather than simply pretend that children can thrive equally well with wet nurses and orphanages, with random bottle holders and busy daycare centers, the natural law configuration emphasizes the vital organic bonds between father, mother, and child—what Brunner called the “trinitarian” one‐flesh union. Rather than simply pretend that every sexual act must be informed by procreative intent in order to pass moral muster, the more liberal natural law configuration emphasizes that sex and intimacy between married couples is an essential good in its own right, regardless of procreative intent, capacity, or result. The rigid procreative perfectionism and narrow reduction of sex to intercourse featured in some modern Christian sexual ethics and natural law theories, in my view, misrepresents a good deal of the teaching of the natural law tradition (Bamforth & Richard 2008; Browning 2006, 207–10).

I believe that this basic understanding of the nature of sex, marriage, and family life remains a reality, a set of natural boundaries and conditions that any modern system of law, ethics, and morality has to work with. I believe further that the way the traditional natural law theory worked out its system of rights and duties, permissions, and restrictions provides us with a valuable foundation for an integrative theory of marriage.

To be sure, some of the scientific assumptions at work in earlier formulations of this model have changed. Genetic testing has made paternity easier to establish. Contraceptives have made extramarital sex safer to pursue. And artificial reproductive technology (ART) has made single, asexual reproduction a greater possibility. But these scientific advances are by no means universally available, nor are they foolproof when available. And while they can expand the sexual experiences and activities of humans, these scientific advances do not alter the core logic at work in the natural law configuration of marriage. Confining sex to marriage was important in earlier times to ensure paternal certainty, but the point of having paternal certainty was to ensure that a man could and would invest in the care of his child and its mother, for the good of all three of them. Using contraceptives certainly widens the opportunities for safe and secret extramarital sex, but it does not meet the traditional concern that rampant promiscuity often leads to sexual exploitation of women and unhealthy sexual libertinism among men. Having ART available certainly enhances the chances of having a child on one's own or with one's spouse, but when a mother has drawn from an anonymous sperm bank or a frozen embryo collection, her child's long‐term concerns for its origin and identity remain unmet. There are many valuable uses for paternity tests, contraceptives, and ART in modern society, notably for married couples as well. But these modern scientific advances do not, in my view, undercut the core logic of the natural law configuration of marriage.

Also to be sure, the modern welfare state now supplies nonmarital children, single mothers, abandoned spouses, and aged parents with vast new resources traditionally supplied principally by their own natural kin, sometimes supplemented by the church's diaconal and charitable services. These social welfare programs, too, are valuable advances that promote social justice and greater happiness for all. But the availability of social welfare relief does not cancel the ongoing value of stable marital households and natural family networks. The modern welfare state remains an expensive and risky modern experiment, and it is not clear to us that this is a sustainable long‐term solution even for the affluent West, let alone for underdeveloped or developing countries. Moreover, even in America today, those who depend exclusively on social welfare, Medicare, and social security often face bitter financial and emotional hardship, and endless bureaucratic wrangling as they seek to secure basic food, health care, and job stability. Better social welfare systems are in place in Europe today. But these, too, depend on high median wealth in the population, all of which can disappear quickly as the examples of Iceland, Ireland, Greece, and Spain—let alone recent cash‐strapped American states—has recently reminded the world. The social welfare state is better seen as a supplement to, not a substitute for, the intergenerational care and nurture provided by a stable family structure.

Even as fully developed, this natural law configuration of marriage remains wobbly and unstable. It provides humans only with natural inclinations not preordained behaviors. It channels humans toward naturally expedient acts, but it is not self‐executing. Even well‐meaning folks stray on occasion from the naturally licit path of sexuality, and some stray all the time. The natural law needs the support of other norms, narratives, and institutions to be fully effective in governing human lives. At minimum, it needs the positive laws of the state to teach these basic norms of sex, marriage, and family life to the community, to encourage and facilitate citizens to live in accordance with them, to deter and punish citizens when they deviate, and to rehabilitate and redirect them to healthier relationships consistent with the norms of natural and civil liberty. It needs the support of other stable institutions besides the state (churches, schools, charities, hospitals, and others) and other stable professionals besides lawyers (preachers, teachers, doctors, mentors, counselors, therapists, and others) to teach, encourage, and implement these natural law norms. And more fully still, this natural law of sex, marriage, and family life needs deeper models and exemplars of love and faithfulness, trust and sacrifice, commitment and community to give its norms more content and coherence, which traditional theologies of covenant and sacrament uniquely offer.

I do not have time or space here to analyze these corollary institutions and broader narratives centered on the idea of a marital covenant. I would, instead, like to turn to the volley of modern criticisms that have been trained on the natural law theory in general, and as applied to sex, marriage, and family life. I will use my responses to these criticisms to nuance my understanding of the natural law of marriage in light of modern scientific and philosophical advances, and to describe more fully the methods by which to discern its contents and contours.

Modern Criticisms of Natural Law Theory

Three major charges are filed against natural law thinking today. First, many critics complain that natural law theory is “foundationalist”—in the philosophical and epistemological sense of that term. They mean by this that natural law theory aspires to ground moral and legal arguments on irrefutable first principles of reason or on objective empirical data and thereby fails to understand how history, socialization, culture, and inherited linguistic traditions shape our sense of right and wrong, virtues and values. From my perspective, the foundationalist critique would be justified if it were a true representation of how natural law thinking functioned in the Western tradition of marriage. But for the most part, it is not accurate in its description of how natural law worked, at least in many strains of Christian thinking about sex, marriage, and family life.

Second, critics of natural law say that it sees both morality and reality as static and unchanging, which is inconsistent with modern views of the world as dynamic, evolving, and constantly changing. This criticism is partially true; many of the presentations of natural law in the past did view it as unchanging and therefore universal. I will argue, however, that the better models of natural law viewed it as unchanging only at certain abstract levels and that at more concrete levels, both nature and the selective pressures of certain situations injected an element of variability into natural law, often through the concept of natural equity.

Third, several critics, even those favorable to certain forms of natural law, argue that official Roman Catholic natural law teachings are far too act oriented. The Catholic magisterium has read the laws of nature as dictating the specific form that concrete actions should take, especially in the sexual and procreative spheres of life: each act of sexual intercourse between a married couple should be open to life, to conception and the eventual birth of a child, and those acts even within marriage that deviate from this norm are immoral. I agree with this criticism, but also think that the magisterium has adopted a much narrower understanding of the natural law tradition even as it functioned within historical Roman Catholic theology.

The Complaint that Natural Law Is Static

The second complaint about natural law is that it is static and pretends to be unchanging and therefore universal. This criticism accepts the modern view that nature, life, and reality are constantly changing either under the impact of evolutionary variation (as the natural sciences teach) or the contingencies of history (as poststructuralism proposes). Both these perspectives now dominate the humanities. From either perspective, natural law can look completely passé. But a careful reading of the tradition reveals that it understood the natural law to be more flexible than this caricature imagines.

At certain abstract and general levels, the natural law tradition may justifiably claim unchanging universality. For instance, consider the thin moral reason view of natural law found in Kant. Kant's categorical imperative—that I should never “act in such a way that I could not also will that my maxim should be a universal law”—claims, as it says, universality and unchangeability (Kant 1959, 18). But many commentators who complain about Kant's claim also admit that the imperative has partial validity for both morality and law. The problem, they might say, is that the imperative stands alone in Kant's formulation; it is disconnected from the premoral goods of natural desire as well as the pressures of history that would qualify what universality might mean in particular circumstances.

The charge of false universality and abstractness can apply as well to the Golden Rule in Matthew 7:12 (“Do unto others as you would have done unto you”) or the New Testament principle of neighbor love in Matthew 19:19 (“You shall love your neighbor as yourself”)—and their common identification as central principles of both the natural and revealed law. It is generally recognized that variations of these two principles show up in all the world religions and are in this sense universal. And the analogies between them and Kant's categorical imperative are obvious. The same criticisms of Kant are often aimed at these principles; they are said to be abstract and hence indeterminate as to what exactly they mean for the moral organization of premoral values in specific social situations. It should be noticed that natural law in this more abstract Kantian sense is widespread in contemporary marriage and family law theory, many of them influenced by neo‐Kantians like John Rawls and Susan Okin. And in various ways, all of them shortchange the premoral levels of moral and legal thinking that are more adequately captured by robust forms of natural law that take nature itself seriously.

Summary and Conclusions

In this paper, I have tried to defend a theory of marriage that builds on the insights of natural law theory. My starting point is the premoral realities that humans are social and sexual creatures; that humans reproduce by sexual pairing; that human sexual capacities and needs are perennial not seasonal; that human infants are born utterly dependent on their parents’ care; that mothers bond with their children through pregnancy and nursing; that fathers will bond with their children when they are assured of their paternity; that mothers, fathers, and children bond with each other when integrated as a group; and that humans are repelled by incest but deeply attached in nonsexual ways to their siblings and relatives, and even their more extended natural kin. These qualities of kin altruism, pair bonding, incest revulsion, exogamous union, childhood dependence, parental recognition, and paternal attachment are the natural realities of human life. They are also, in some formulations, the elementary building blocks of human evolution. Together they form, what Bernard Chapais called, the “deep structure” of the human species.

How we come to discover and understand these premoral realities of human nature, interaction, and reproduction has long been a contested issue in the tradition, and that remains true today. I have rehearsed various methodological strategies and examples—from empirical and experimental investigations, to comparative cultural and sociological analysis, to philosophical speculation and construction. I am most attracted to the methodology of Paul Ricoeur, who recognizes the presence of these natural instincts, inclinations, and intuitions in human lives, but shows how each culture variously orders, prioritizes, and acts on them based on experience, reason, tradition, and an ontology that comprehends the full complexity of human experience. However they are discovered, defined, and defended, I believe that these basic realities of human nature, interaction, and generation must form the foundation of any integrative theory, ethic, and law of marriage and the family. A normative system that defies these natural realities will not long work in practice, however cogent it might be in theory.

Historically and today, various Christian writers have woven these premoral natural qualities of humans into natural law arguments about the proper ordering and organization of sex, marriage, and family lives. On the one hand, they used natural law arguments to single out various sexual activities that defied or damaged human nature and the natural rights of men, women, and children: fornication, adultery, concubinage, prostitution, incest, rape, polygamy, desertion, child abuse, wife abuse, no‐fault divorce, and more. On the other hand, they used natural law arguments to channel and encourage men and women to follow their natural instincts toward exclusive and monogamous unions, mutual comfort, care, and protection of each other, healthy and regular sex and other forms of communication, mutual investment in the care, nurture, and education of their children, intergenerational care for their natural kin, and presumptive provision for their dependents even upon divorce or death.

These natural law arguments of sex, marriage, and family, too, have long been pressed on various grounds, and defended with various rationales. In early iterations, these natural law arguments were sometimes combined with arguments from the Bible and cast in static universal terms. More recent Christian natural law theorists, however, have defended natural law arguments on more empirical, scientific, and evolutionary terms and recognized the inherent plasticity and necessary adaptability of some of its provisions. In some Catholic iterations today, these natural law arguments proceed with a rigid moral perfectionism and narrow analytical casuistry that some view as complex rationalizations for predetermined dogmatic stands on sex, marriage, and family life. Most Christian natural law theorists, both Catholic and non‐Catholic, and both historical and contemporary, have adopted a far more flexible and holistic theory of natural law and the goods and goals of marriage.

It must be said that the natural law configuration of sex, marriage, and family, while foundational to any integrative theory of marriage, cannot operate alone in a complex modern society, because it is not self‐executing. The natural law needs other institutions and practices, other ideas and narratives to stabilize, channel, and direct it. Law and theology, state and church—holding out contracts and covenants of marriage respectively—are among these essential resources. But that is an argument for another—and much longer—article.