NATURAL LAW

A law or rule of action that is implicit in the very nature of things. The term is sometimes used in the plural form to designate laws that regulate the activities of nature in both the organic and the inorganic realm. Properly speaking, however, it is exclusively applied to man and designates a prescriptive rule of conduct naturally received by and measuring human reason which enables human reason rightly to measure human action. For St. thomas aquinas, "natural law is nothing other than the participation of eternal law in rational creatures" (Summa theologiae 1a2ae, 91.2); thus Aquinas conceives it as the imprint of God's providential plan on man's natural reason. This article is divided into three main sections. The first treats of the historical development of the concept of natural law; the second provides a Thomistic analysis of the concept; and the third discusses the place of the concept in contemporary theology and philosophy. (For specific applications of the concept, see natural law and jurisprudence; natural law in political thought.)

historical development

Although natural law has always been perceived in its basic content by human beings, its concept has been formalized, elaborated, articulated, and systematized only with the growth and development of philosophy. The historical evolution of this doctrine may be conveniently traced through six periods: (1) the pagan period, corresponding to that of the Greco-Roman world and extending from heraclitus to St. Paul; (2) the Catholic and scholastic period, extending from St. Paul to Hugo grotius; (3) the Protestant and post-scholastic period, extending from Grotius and S. von Pufendorf (1632–94) to J. Bentham; (4) the period of decline, corresponding to the rise of positivism and extending from bentham and D. hume to F. Gény (1861–1959) and R. Stammler (1856–1938); (5) the contemporary period of revival, extending from Gény and Stammler to the mid-1960s; and (6) the debates of the late 20th century.

Greco-Roman Period. There is evidence of the idea of a universal divine law binding on man in Oriental literature, such as that of China, long before the rise of philosophy in the West. But the origin of a natural-law doctrine, with its elaboration as an unbroken, continuous development, is first to be found among the ancient Greek poets and historians. Thus Sophocles (c. 497–406 b.c.), Thucydides (c. 460–400 b.c.), and Xenophon (c. 427–355 b.c.) presented a concept of the natural law that is divine, universal, and known to all.

Greek Philosophers. A development of this early Greek notion appears in the writings of Heraclitus, who held that the natural law is eternal and immutable, the foundation of human laws (Fragments 102, 112–116). Other Greek philosophers, such as plato, elucidated this doctrine (Laws 715, 884–910; Rep. 419–445). It was left to Plato's student aristotle, however, to clarify the distinction between natural law and law that is humanly enacted (Eth. Nic. 1134b 18–1136a 9; Rhet. 1373b 1–18). Such Greek philosophers used observation and experience to discover an order in the universe that they associated with a predictable, regular recurrence of events. Traceable to the activity of animate and inanimate matter, this recurrence is in response to an ordering principle or law that rules the cosmos. But man also is part of the cosmos and hence subject to an ordering law, which in his case is the right or just by nature. Morals and human law, for the Greeks, thus have their foundation in the harmony of nature or the natural law. This law exists independently of human will and has universal validity. It provides objective principles and ideals to which human beings must conform, by their very nature, as part of the cosmos. Functionally, therefore, natural law affords a measure for the wise, the good, the just, the prudent, and the happy man. It provides too a basis for an idealized political and social order. It also makes possible the distinction between the category of divine, universal, and unchangeable law and that of human, politically enacted, and variable law.

Whereas Aristotle does not thematize the theological and metaphysical element the definitory relation to eternal law—so strongly as do either earlier figures such as Heraclitus, later authors such as Cicero, or in the Christian era Boethius, Augustine, or St. Thomas Aquinas, it is nonetheless clear that the naturally just and virtuous is a function of conforming to natural order that is derived from its divine origin, and whose entailments in virtue are analogously "divine." The ordering of human nature to a hierarchy of perfective ends prior to choice is essential to his teaching; hence his strong emphasis upon the truth that strictly speaking the end is not directly a matter of choice. Man is by nature ordered to happiness as his final end, and that which by nature constitutes this happiness is a function of the teleological order of man to contemplation of God and the virtues appropriate to the active life.

Nonetheless, the idea of natural law at this stage of its evolution tends to subordinate the individual to the Greek city-state. Even for Aristotle, individual man achieves the perfection of his human nature through law only in the good order of the city-state, which is analogous to the cosmic order (Pol. 1252a 1 1253a 38). The doctrine of natural law reached its highest development in the pagan world within stoicism, the philosophical movement founded by Zeno of Citium (c. 336–c. 264 b.c.). Characteristic of Zeno's teaching and that of other Stoic philosophers, such as Chrysippus (c. 280 b.c.), was the thesis that man is a citizen of the world. Thus emphasis was placed on the nature of man as such and not merely as related to political society. A broader society consequently results from human nature itself, which is subject to the law of right reason. The individual thus comes to be recognized as a moral unit who is governed by universal law, which prescribes a pattern of conduct that is discoverable by reason. In this way, law and justice are seen as transcending the confines of the city-state.

Roman Thought. After the military conquest of Greece by Rome c. 146 b.c., the Stoic idea of natural law began to infiltrate the Roman world. cicero played an important role in interpreting and disseminating this idea. For him, natural law is the highest reason implanted in nature, transcending space and time; it is eternal and unchangeable, the same in Rome as in Athens. Coming from God, it commands what is to be done and forbids what is to be avoided. It precedes written law and the state. More specifically, it embodies basic principles (e.g., the right of self-defense against aggression), regulates justice (giving to each his due), and promotes the common good. It also forbids fraud and theft. Among the Romans, natural law came to be chiefly related to the juridical and legal orders. The natural right, or the just by nature, therefore became the ius naturale of the Roman jurists, i.e., a speculative body of universal moral ideas and principles.

The ius civile, or body of legal precepts, was applied exclusively to Roman citizens. But eventually, after Rome became a great maritime and trading center, it became necessary to supplement the ius civile with the ius gentium, or body of law for foreigners. As positive law, the ius gentium was constructed from the common denominator of principles obtaining in the various legal systems of countries from which foreigners came. The policy of using this common denominator was rationalized on the grounds that it was only the implementation of the ius naturale, the expression of universal reason. By the end of the classical age of Roman jurisprudence, i.e., about 300 years after the death of Cicero, hundreds of texts had referred to ius naturale, naturalis ratio, and rerum natura. Thus Ulpian (d. a.d. 228), the great Roman jurist, stated that insofar as the ius civile is concerned, slaves are not regarded as persons; nevertheless, this is not true under natural law because under that law all men are equal (Digest 50.17.32). Ulpian was obviously referring to the natural law when he wrote that the precepts of the law are to live honestly, to harm no one, and to render each his own (Institutes 1.1.3; Digest 1.1.10). Most Roman jurists, such as Gaius (2d century a.d.), oriented the legal order toward the natural law primarily by following the standard of objective right reason as manifested in experience (Institutes 1.156, 158).

Catholic and Scholastic Period . Although the Fathers of the early Christian Church understandably emphasized the "new law" of revelation rather than simply the natural law, nonetheless the conception of natural law was integral to their theology. Among those authors in whom this is clearest are St. paul, St. john chrysostom, St. augustine, and St. isidore of seville, all of whom borrowed Stoic ideas in describing the interrelationship between natural and supernatural laws. The Stoics had been equivocal as to whether the ultimate source of natural law was personal and divine or whether divinity was immanent in nature in the sense of a monist pantheism. It was impossible for them to synthesize natural law with the myths of the pagan religions of their time. In this area, the Fathers of the Church, and later the scholastics, were able to supply new insights based on supernatural revelation.

Early Christianity. St. Paul, the Apostle of the Gentiles, wrote that the natural law is inscribed in the hearts of all men, even though all do not have the Law (of Sinai) of divine revelation (Rom 2.12 16). St. John Chrysostom taught that the natural law is promulgated through man's conscience, which supplies the basis of human law (Ad pop. ant. 12). According to St. Augustine, the ius naturale comes from a personal, all-wise, and all-powerful God, the same God who has authored the Christian Scriptures; hence natural law is not derived from nature in the pantheistic sense (Civ 11.4.2). St. Isidore of Seville held that all laws are either divine or human and that ius naturale is the law observed everywhere by the instinct of nature, such as that ordaining the marriage of man and woman, the procreation and rearing of children, and the like. It is not human positive law (On Laws 4).

Canonists. The canonists, especially as seen in the Decretum of gratian, were chiefly responsible for transmitting the interrelationship between natural and supernatural law that had been worked out by the Fathers to the golden age of scholastic philosophy. According to Gratian, all justice is founded on natural law, which is of divine origin (Decretum 1). This law goes back to the beginning of mankind; its content is to be found in the Ten Commandments and the Gospel, which dictates the golden rule of doing to others what one wishes done to oneself. A decade after Gratian, the canonist rufinus referred to the natural law as the divine power that nature implants in man, impelling him to do good and avoid evil (Summa Decretorum ).

Thomistic Concept. But it remained for St. Thomas Aquinas to perfect the idea of natural law. This he did by distinguishing in the natural law of the Stoics and in the ius naturale of the Romans the lex aeterna and the lex naturalis. The eternal law is the plan of the divine providence governing the cosmos, man, and matter, both animate and inanimate. It is the ordering wisdom of God. Natural law is that part of the eternal law that is properly applicable to man alone, although it may be spoken of lower creatures by a kind of analogy. All creatures— including human creatures—passively receive their being, natures, and natural ordering to perfective ends from God. But man's creation as a rational being enables him to receive this ordering of his nature as providing reasons to act and not to act. Human reason takes its measure from the objective ordering of human nature to the order of ends that perfects it.

Natural law is in accord with man's nature (Summa theologiae 1a2ae, 91.2 4). Subrational creatures and inanimate matter must obey the eternal law, but man can disobey it because he has freedom as to moral choice. However, he ought to obey the natural law, for otherwise he violates his nature. Thus did Aquinas correct the error of Ulpian, who is quoted in Justinian's Digest (6th century a.d.) as having declared that the law of nature is not peculiar to the human race but belongs to all creatures (1.1.1 4). Ulpian had made the natural law (a part) identical with the eternal law (the whole).

According to Aquinas, ius naturale is encompassed within lex naturalis insofar as it relates to man. By this semantic change he gave rationally discovered law a statutory connotation, while insisting that natural law has the same source as supernatural law. But Aquinas did not destroy the rational basis of the pagan, Aristotelian-Stoic doctrine of natural law by substituting the authority of supernatural law, in the sense of truth revealed in the Bible, in its place. Rather, to use a metaphor, he taught that the single coin of divine law is stamped on one side by the supernatural law of Judeo-Christian theology, accepted on faith, through grace, as the word of God, and on the other side by the natural law, perceived by reason. Inasmuch as both laws emanate from a single source, they can never be in conflict. Precisely because man is called to an end surpassing nature, a law higher than the natural law is required to direct him to this end, but the "new law" of grace elevates and perfects nature rather than destroying it. According to Aquinas, natural law is nothing other than a participation in the eternal law. Gradually the emphasis would shift to nature, and then finally collapse into the solitary emphasis upon what law is known first.

Later Thought. In the 14th century, the Thomistic view of natural law was challenged by some. Thus, duns scotus wrote that lex naturalis has no intrinsic connection with the essence of God and hence can be different from what it happens to be (Op. Oxon. 1.8.5. 22–23). william of ockham held that natural law is wholly the product of divine will; it is divine positive law, or supernatural law, since God is primarily absolute and omnipotent will (Quodl. 1.10.3; 1.13). Both deviated, therefore, from the Thomistic idea of natural law by eliminating intellect and reason from its authoritative basis. But in the 16th century, reason was restored to the doctrine of natural law by Spanish jurist-theologians such as Domingo de soto (De iustitia et iure 1.5.2) and Francisco suÁrez (A Treatise on Law and God the Lawgiver 2.6.5). These thinkers affirmed that the ultimate source of the natural law is in the divine will and intellect; and its proximate principle, in the essence of man. They also emphasized a historical-analytical and comparative-empirical approach that gave content to natural law, particularly in the field of international relations.

Protestant and Postscholastic Period. The outbreak of the Reformation in the 16th century initiated a new period in the history of the doctrine of natural law. The term "natural law" had been so long embedded in the thinking of the Western world that philosophers and jurists continued to use it after the Reformation, although they attributed to it an essentially new and heterogeneous content. Insofar as the theology of the Reformation affirmed the private interpretation of the Scriptures, it led to the rejection of the idea of objective truth in the areas of both supernatural and natural law. The conscience of the individual became more than the source of personal moral responsibility; it became the measure of truth in all matters of right and wrong, good and evil. Subjective theories of natural law, detached from the element of experience, began to postulate the existence of a state or condition of nature in which man lived before he constructed politically organized society. In this state of nature, there was a "law of nature." This myth of the natural state often was a "counter" to the theological account of Eden and the fall of man. Moral and social disorder would be traced, not to original and actual sin, but to natural dynamisms which condition and to some extent war against social order. Unlike the natural law, the law of nature was not related chiefly to conduct in general nor to the legal and theological orders, but rather to political order. This emphasis accompanied the rise of political problems ensuing from cuius regio eius religio (the religion of the state is that of whoever reigns), i.e., the emergence and growth of national states and churches.

Law of Nature School. According to the law of nature school, man perceives the natural law by his subjective faculty of reason, which contemplates human nature as an abstract essence existing in a vacuum, apart from time and place. Man determines the content of the law of nature not by induction but by a purely deductive process. (The scholastics had made use of induction here, studying the standard of right reason in relation to historical and contemporary experience.) The law of nature school exalted the autonomy of the individual faculty of reason; that this led to an excessive subjectivism is evidenced by the basic disagreement within the school over the state of nature, the content of the law of nature in this aboriginal condition, and its fate once man established politically and legally organized society by a social contract.

Grotius. The contributions of Hugo Grotius effected the transition between the scholastic and the law of nature concepts of natural law. Like the scholastics, Grotius believed in the existence of objective right reason, with resulting immutable principles, and in God as the highest source of natural law (De iure belli ac pacis 1.1). Unlike them, he held that the natural law could exist even without a personal and divine Law-Giver, since it had a sufficient basis in reason alone. He also stressed individualism, rationalism, and the social aspect of rational human nature in reference to natural law (ibid. 1.3.8). But he did not go so far as to hold that the social nature of man is the sole source of natural law. Grotius erred in believing that man once lived in a state of nature under a law of nature that could be derived from man's essence. He taught that it was possible to deduce by strict logic a complete system of principles with universal validity and from these to develop an all-sufficient code of legal rules (ibid. prol.). He thus failed to distinguish the immutable aspects of the natural law, the mutable conclusions that result from the application of immutable principles to changing factors, and the positive law that implements both types of principles. Under his law of nature doctrine, therefore, natural law lost the flexibility and dynamism it had enjoyed in the prior periods.

Pufendorf. Samuel von Pufendorf first articulated the concept of the law of nature in its pure or classical form. For him, the ius naturale is related to God's will, not to His essence. It is not a rational participation in the eternal law, as Aquinas taught, but is identified wholly with the human impulse toward sociability. The sociable capacity of man is the sole proximate source of natural law, the starting point of speculation in this sphere (De iure naturae et gentium 2.3). Pufendorf considered reason so autonomous that in effect civil law, both substantive and procedural, became natural law, even though in theory he distinguished between natural law and positive law. For him, natural law is only a model law, advisory but not mandatory. Hence the state enacts positive law so that the natural law may be obeyed (ibid. ).

Hobbes and Locke. The great divergence among the various adherents of the law of nature school may be seen by comparing the views of T. hobbes with those of J. locke. Hobbes saw the state of nature as a state of war of all against all, in which the life of man is solitary, poor, nasty, brutish, and short. The basic norm is self-preservation, springing from natural law, which is a dictate of right reason regarding things to be done or omitted for the preservation of life and limb. The first fundamental law of nature is that peace be sought, and all other natural laws are derived from this. Morality is rooted, therefore, in peace; this is the reason why agreements must be kept (Leviathan 13). According to Hobbes, the law of nature prescribes that man should form the civil state in order to preserve the fundamental right to life. In establishing the state, however, man surrendered his freedom, equality, and the right to everything he had enjoyed in the state of nature, physical survival alone excepted. This was done by a covenant. The will of the resulting omnipotent state is based on the fundamental principle that agreements must be kept. Man may not morally resist the state because its enactments are natural law. Indeed the state, as the authoritative interpreter of both natural and supernatural law, was transformed into a mortal god in a literal sense. If there is a conflict between a command of the state and the private moral judgment of the individual, Hobbes advises the latter to go to Christ by martyrdom (ibid. 18). But for Locke, contrary to Hobbes, the historical state of nature was a condition of peace, good will, and mutual cooperation. Man enjoyed the right of freedom and equality, as well as the right to work and own property. The law of nature dictated justice, but the authority of civil society was necessary to enforce it. Politically organized society resulted from a social contract, but the continuing obligation of obedience on the part of the people depends on the proper observance of that contract by the sovereign (Second Treatise on Civil Government 19). For Locke man is not, in the strict sense, under any obligation of law prior to the convening of the state, nor is man obligated to convene such a state. Rather, Locke sees natural law as a dictate of practical common sense a nominalistic symbol for the rights of the individual, reflecting his self-interest. These rights do not emanate from the natural law by intrinsic necessity; rather, they limit the political sovereign and should be enforced by human positive law (ibid. 9).

Others. Conceptions of the state of nature and the law of nature found therein were expressed by J. J. rousseau (The Social Contract 1.8, 2.6, 4.2), C. Thomasius (Fundamenta iuris naturae et gentium ), C. wolff (Institutiones iuris naturae et gentium 2), and others. The term "law of nature" became so ambiguous that it was used to justify such divergent theories as enlightened despotism, state absolutism, and the omnipotence of the democratic state. The ultimate position was that each individual's reasoning faculty manufactures natural law, rather than discovers it. These accounts, for the most part, do not situate natural law within a wider metaphysical and theological context.

Kant. The tendency to separate natural law from the foci of eternal law and nature is brought to its consummation in the doctrine of I. kant, who introduced a new doctrine of objective right which is only equivocally related to classical natural law. He argued that the state of nature was only a historical fiction to explain the foundation of the civil state, since man had always lived in a social state (in this narrow regard, his doctrine shares something with Aristotelian and Thomistic teaching). However, he also maintained that man cannot reach the ideal, or perfect, law by a process of pure reason (The Philosophy of Law 1; Introduction to the Metaphysics of Morals 4.24). Kant argued that the formal, subjective elements of the reasoning process do not come from experience, and that they are valid only insofar as they are referred to some possible experience. Hence Kant denied the very possibility of metaphysical truth, since on his account first principles are not derived from the mind's initial contact with being, but are rather pure emanations of universal human subjectivity. What remains is human experience understood as shaped by universal subjective categories which on the Kantian view cannot be known to pertain to reality as such. Hence causal knowledge of the reality of God, the reasoned understanding of the nature of human freedom as a corollary of the nature of the human intellect, and the proofs for the immortality of the human soul are set aside and become mere subjective postulates of practical reason. Likewise, Kant reduces the ordering of nature to perfective ends to a mere empirical datum that in no way defines moral duty and may even serve as a motive for immoral breach of duty.

Kant projected an individualist idea of natural right. Freedom of will became the ultimate, supreme, immutable value, a natural inborn right that included all natural rights. He reconciled the conflict between the equally free wills of the various individuals in society by a categorical imperative, a universal law directing that each individual should so act that the free exercise of his will would enable him to live without interfering with the like freedom of others. Under this theory, natural law is not a part of an eternal law, although the natural law supplies the immutable ideal of freedom upon which the categorical imperative is constructed. The categorical imperative is imposed by a necessity inherent in the very idea of freedom.

Period of Decline. The Enlightenment accounts of natural law shorn of metaphysics and theology and progressively reduced to immanent nature and finally to Kant's formalism of pure right reached a high degree of prestige at the end of the 18th century, but it gave way in the 19th century to positivism, which held the authority of the state to be supreme in every sense. The reasons for this decline may be enumerated as follows. First, even before the dawn of the 19th century, D. Hume laid the groundwork for the widespread assault on natural-law doctrine. A skeptic, he proclaimed that the human mind can never attain the essences of things and that it cannot determine what is intrinsically morally good or evil. Morality is not a matter of idealism but is determined by the sentiment of approval, itself related to the useful. According to Hume, the moral law has no basis in the rational and social nature of man and has no connection with immutable truth. Second, positivism was promoted by individualist utilitarians, such as J. Bentham (Treatise on Legislation 13). In place of idealism, Bentham substituted the notion of utility as measured by the greatest good or by the happiness of the greatest number, taking happiness in the sense of personal satisfaction and advantage. Bentham sought consciously to build a new body of law. He was the forerunner of John Austin (1790–1859), who created the analytical school of jurisprudence, a school widely influential among Anglo-American jurists. Third, the historical school, founded by F. K. von Savigny, contributed indirectly to the rise of positivism. It maintained that natural, or ideal, law springs spontaneously from the spirit of a people and is reflected in custom. It is a higher law, found and not made. For this school, customary law, like natural law, limited the authority of the political sovereign to make law. Yet the historical school was positivist in its ultimate philosophy, for it believed that customary law was the result of the will of the people yielding to non-rational impulses and responding to historical necessity rather than to right reason. Fourth, positivism was advanced by the newly emerging science of sociology, which had its origin in the writings of positivist philosophers such as A. comte. Assuming a mechanistic view of the physical universe based on mathematically demonstrable laws that control the activity of nature, it regarded moral and social laws as analogous to the law of gravitation. Sociological jurisprudence later abandoned this approach.

Correctives to the Law of Nature. From the viewpoint of the scholastic doctrine of natural law, it is understandable, however, why the analytical, historical, and sociological schools were able to attract a following. Each of these schools in its own way corrected a deficiency of the pseudoconcept of natural law that had been developed in the 17th and 18th centuries. Whereas Aquinas had visualized man as a rational and social animal who relies on both reason and experience and needs a legal order enforced by a temporal sovereign, the law of nature school overemphasized subjective reason in its analysis. These reactions against the law of nature school were therefore quite legitimate, even though they had little to do with the natural-law doctrine of Aquinas. The analytical school focused attention on legal analysis and the logical interdependence of legal rules and precepts; it stressed the fact that law is in the external forum and should be enforced by the sovereign. The historical school restored the factor of experience. The sociological school reintroduced the element of the social status of man and the means-ends aspect of law, as maintained by Aquinas. Each of these schools erred, however, by concentrating on one factor to the exclusion of others and by refusing to accept any immutable moral value, such as the dignity of the individual. Other factors that contributed to the rise of positivism included the search for an explanation to justify absolute political sovereignty in both domestic and foreign affairs, the thrust of moral relativism related to anthropological studies, the rejection of a priori postulates by the physical sciences, and mistaken ideas about human evolution, empiricism, pragmatism, and materialistic psychiatry.

Period of Revival. A reaction against the sterility and ineffectiveness of positivism began with a revival of natural law doctrine. This revival was led by F. Gény, a neoscholastic, and R. Stammler, a neo-Kantian. Both scholars emphasized the sociological aspects of the natural law, an emphasis that has continued throughout the contemporary period. Gény began the revival in France by considering the social life of the individual as a moral phenomenon governed by the natural law as understood by Aquinas. He used the Thomistic doctrine of natural law to provide a much-needed equitable and sociological interpretation for European codes. Gény's notions received great encouragement from Pope Leo XIII, especially through his encyclicals relating to political and social matters, such as libertas (1888) and rerum novarum (1891), and by succeeding popes (see scholasticism, 3). Renewed interest in the scholastic doctrine of natural law as this relates to the legal and social orders began in the United States in the 1920s and 1930s. Law reviews sponsored by such universities as Fordham, Detroit, Marquette, Georgetown, and Notre Dame became channels for an ever-growing literature. The American Catholic Philosophical Association established a committee on the philosophy of law in the early 1930s that arranged an annual forum for the presentation of papers relating to natural law and the solution of legal and social problems. These bodies expanded further the body of natural-law literature. The revival of natural-law doctrine was enormously accelerated by the experience of two world wars. European emigrés contributed much on the North American continent to the renascence of natural-law teaching. Jacques maritain, Yves simon, Heinrich Rommen, and others, made cogent argument in behalf of the tradition of natural law given classical articulation by St. Thomas Aquinas. Many legal philosophers, recoiling from the horrors of untrammeled state power after the Nazi experience, took up with interest the consideration of a higher law than the positive law of the state. After World War II, it was manifest that such a doctrine alone could provide an authoritative basis for upholding the intrinsic dignity of the individual against ruthless dictatorship. The quest for political and legal justice resulted in the rediscovery that there is a moral order springing from an authority beyond the human will. The theological/metaphysical aspect of the tradition was rekindled in the consideration of the theonomic character of natural law, while concern for the legal/juridic/moral implications of the natural law also intensified. Interest in the doctrine of the natural law was evidenced in the United States by the Journal of the American Bar Association, the Natural Law Forum of the University of Notre Dame, and the Catholic Lawyer, published by the St. Thomas More Institute for Legal Research of St. John's University, New York. Southern Methodist University, Dallas, sponsors an annual symposium on natural law; and Loyola University, New Orleans, houses an institute on natural law as related to the solution of some contemporary social problem. The revival of natural-law doctrine has been widespread in Latin America, especially in Argentina and Mexico; in Europe it flourishes particularly in Italy, Germany, France, and Spain; and it is evident in the Orient.

Nonscholastic Circles. Stammler initiated a revival of the neo-kantian doctrine of natural right. For him, the content of the natural law is wholly changeable and changing, dependent upon the social ideals and conditions of a particular time and place. Through natural law, all possible individual goals of the community of freely willing men are to be harmonized. He thus reconciled the idea of natural law with the notions of evolution and utility. A later neo-Kantian development in the field of legal philosophy was led by Giorgio del Vecchio. His position is closer to the Thomistic than that of Stammler. Indeed, the position of Del Vecchio represents the tendency to minimize the speculative aspect of natural law theory so as to avoid the antimetaphysical criticisms flowing from Kant and Hume. He admits the existence of a divine Law-Giver who has given man a supernatural law by revelation, but he does not relate this Law-Giver to the natural law. He derives the elements of transcendence and immutability for his juridical idealism from the essence of man rather than deriving them from the divine will and intellect. Other nonscholastic doctrines that deploy the terminology of "natural law" have rejected any immutable, transcendental, objective ideal of conduct to which man should conform his behavior. Exponents of this type of natural-law doctrine, such as M. R. Cohen (1880–1947), accept the existence only of relative ideals for human conduct. But these ideals do exist a priori in an objective order and do not arise solely from facts. For such authors as well as for the neo-Kantians, the "ought" stands in juxtaposition to the "is." This is to say that these theorists embrace a pronounced dichotomy of nature and the good, divorcing practical knowledge from its speculative roots along Humean lines. Other natural-law writers, such as L. L. Fuller and Jerome Hall, deviate more markedly from the scholastic idea of natural law. They believe that there are ideals for the evaluation of man's conduct, but that these are principally generalizations of what will best advance the social interest.

Late 20th Century. The late 20th century has seen substantial work and controversy within all the major areas of natural-law theory, from theology and metaphysics, to natural ontology, to epistemology, to law and jurisprudence. This all-encompassing controversy and research is attributable to four distinct historical influences. First, it is in part due to the engagement of natural lawyers with radical theological pluralism following the Second vatican council; second, it also flows from reactions against proportionalism on the one hand, and even more fundamentally against Humean and Kantian anti-metaphysical tendencies, on the other; third, it is a result of legal and political pressures and the growing volatility on the North American continent of Church-state legal issues, about all of which the tradition of natural law provides an important context for understanding; and fourth, the general encroachment of such reductionist methods as historicism, relativism, and scientism entails a proportionate response at every level of reasoning (see Pope john paul ii, fides et ratio). Out of this dense weaving and interweaving of themes and controversies, three points are clear: the renascence of natural-law theory, especially in Thomism but also in competing and contrasting accounts such as the new natural-law theory championed by Grisez and Finnis; the special impetus given to the metaphysically founded Thomistic natural-law reasoning by the encyclicals veritatis splendor and Fides et ratio ; and the importance of work done regarding both the significance of a normative conception of nature for theology, and of work applying natural law reasoning to jurisprudence and politics.

The New Natural-Law Theorists. During this period of time, the "new natural-law theory" propounded by and John Finnis has gained adherents while undergoing serious criticism from proponents of more traditional Thomistic natural-law theory. Grisez's influential work, The Way of the Lord Jesus, has brought this account to the foreground. Grisez and Finnis argue for a methodological and, as it were, temporary epistemic separation of the precepts of natural law from their speculative context, insisting that the prime precepts of the natural law are in no way derived from speculative truths. They also argue that basic moral goods are simply incomparable and do not exemplify any morally significant order amongst one another prior to human choice—what is called the "incommensurability thesis." Arguing for the existence of universal moral norms, including negative norms, these authors strongly criticize proportionalism, while also denying the claims of more traditional Aristotelians and Thomists that moral goods or ends exemplify a teleological hierarchy that is morally significant prior to choice.

Thomistic and Aristotelian Natural-Law Theorists. An important school of Aristotelian and Thomistic philosophers has argued that although the transition from knowledge of nature to preceptive norms is not simply a function of definition, nonetheless it is impossible even temporarily to detach epistemic awareness of the natural law from its ontological foundation. Ralph McInerny has extensively criticized the new natural-law theorists' account of the first precept of law, as well as their denial of the ethical significance of natural teleology. Henry Veatch engaged in a lengthy and lucid discussion with theorists of the analytic tradition, seeking to vindicate natural teleology within ethics from essentially Humean and Kantian criticisms. Russell Hittinger, in particular, has argued that the method of the new natural-law theorists tends toward fideism insofar as it separates natural-law duties to God from the speculative natural knowledge of the reality of God. He has set forth a strong argument that natural law is unequivocally "law"—that, as St. Thomas writes in the prologue to his treatise on law in the Summa theologiae, law is indeed an "extrinsic" principle, since ontologically the law and that of which the law is the norm are not one and the same.

Other Theorists. In addition to the well-delineated Thomistic and New Natural-Law Theory schools, a variety of other prominent authors have persisted in contributing important analyses and discussions. Most prominently, Martin Rhonheimer has set forth an interpretation of Aquinas on the natural law in Natural Law and Practical Reason (New York 2000). Rhonheimer argues, against the general weight of the Thomistic school, that man's reason is the formal promulgator of the natural law. Like the New Natural-Law Theorists, he seeks to rescue natural law from the claims that it is physicalistic or merely naturalistic, which places his work at the very crossroads of the dispute of the Thomistic School with the New Natural-Law Theorists.

Bibliography: b. f. brown, ed., The Natural Law Reader (New York 1960). g. del vecchio, Philosophy of Law, tr. t. o. martin (Washington, D.C. 1953). a. passerin d'entrÉves, Natural Law (London 1951). d. fitzgerald, "The State of Nature: Theories of the 17th and 18th Centuries and Natural Law," American Catholic Philosophical Association, Proceedings of the Annual Meeting 32 (1958) 161–172. j. f. garcÊa, "The Natural Law," ibid. 22 (1947) 1–18. c. a. hart, "Metaphysical Foundations of the Natural Law," ibid. 24 (1950) 18–28. j. maritain, The Rights of Man and Natural Law, tr. d. c. anson (New York 1943); Man and the State (Chicago, Ill. 1951). Notre Dame Univ., Natural Law Institute: Proceedings 1:5 (1947–1951). r. pound, "The Revival of Natural Law," Notre Dame Lawyer 17 (1941–42) 287–372. h. a. rommen, The Natural Law, tr. t. a. hanley (St. Louis 1947). y. simon, The Tradition of Natural Law, tr. v. kuic and r. j. thompson (New York 1992). j. finnis, Natural Law and Natural Right (Oxford 1980); Aquinas, Moral, Political, and Legal Theory (Oxford 1998). g. grisez, The Way of the Lord Jesus, 3 v. (Chicago 1983–1997). r. mcinerny, Ethica Thomistica (Washington, D.C. rev. ed. 1997). r. hittinger, "Natural Law and Catholic Moral Theology," in A Preserving Grace, ed. m. cromartie (Washington, D.C. 1997); "Natural Law as Law," American Journal of Jurisprudence 39 (1994) 1–32; A Critique of the New Natural Law Theory (Notre Dame, Ind. 1987). h. veatch, For an Ontology of Morals (Evanston, Ill. 1971). l. dewan, "St. Thomas, Our Natural Lights, and the Moral Order," Angelicum 67 (1990) 283–307; "St. Thomas, John Finnis, and the Political Common Good," The Thomist 64 (2000) 337–374; s. a. long, "St. Thomas Aquinas Through the Analytic Looking Glass," ibid. 65 (2001) 259–300. s. pinckaers, The Sources of Christian Ethics, tr. m. t. noble (Washington, D.C. 1995). r. cessario, The Moral Virtues and Theological Ethics (Notre Dame, Ind. 1992); Introduction to Moral Theology (Washington, D.C. 2001).

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THOMISTIC ANALYSIS

Natural law, as can be seen from its history, has been the subject of much controversy. A partial explanation for this is that advocates of natural law have frequently ignored its ontological basis and adopted as their starting point what they considered the distinctive characteristic of human nature. As each proponent had his own concept of human nature, it was inevitable that each would have his own peculiar philosophy of natural law. Yet when viewed in isolation from its ontological origin, human nature itself furnishes norms that have little more than psychological validity. confucius and his early disciples recognized this. Thus the opening sentence of the Confucian classic, The Unvarying Mean, reads: "What is ordained of Heaven is called the essential nature of man; the following of this essential nature is called the natural law; the cultivation and refinement of this natural law is called culture." The Confucian view is close to that of St. Thomas Aquinas, who held that natural law is a participation of the eternal law in man, and that positive law consists in variable determinations of immutable fundamental principles as these are applied to the varying conditions and circumstances of social life. For both Aquinas and Confucius, positive law, itself an integral part of culture, is a development and implementation of the God-given natural law that man bears within him. This part of the article presents an analysis of the concept of natural law based on the philosophy of St. Thomas Aquinas. It discusses the relation of natural law to eternal law and positive law, the essentials of natural-law doctrine, the effects of natural law, man's awareness of the law, and its various confirmations in divine revelation and in papal teaching. More recent philosophical positions that are relevant to contemporary developments in theology are discussed in the third part of the article.

Relation to Eternal Law and Positive Law. Eternal law, natural law, and positive law, though distinct from one another, form a continuous series that may be compared to a tree. The eternal law is its hidden root; the natural law is its main trunk; and the different systems of positive law are its branches. All systems of human law contain, in varying proportions, natural principles and positive rules. The former are not made but are merely declared by human authority; therefore they may not be abrogated. In the words of Pope leo xiii:

Of the laws enacted by men, some are concerned with what is good or bad by its very nature; and they command men to follow after what is right and to shun what is wrong, adding at the same time a suitable sanction. But such laws by no means derive their origin from civil society; because just as civil society did not create human nature, so neither can it be said to be the author of the good which befits human nature, or of the evil which is contrary to it. Laws come before men live together in society and have their origin in the natural, and consequently in the eternal, law. The precepts, therefore, of the natural law, contained bodily in the laws of men, have not merely the force of human law, but they possess that higher and more august sanction which belongs to the law of nature and the eternal law. (Libertas praestantissimum, June 20, 1888)

Of the positive rules of law, the same Pontiff said:

Now there are other enactments of the civil authority, which do not follow directly, but somewhat remotely, from the natural law, and decide many points which the law of nature treats only in a general and indefinite way. For instance, though nature commands all to contribute to the public peace and prosperity, still whatever belongs to the manner and circumstances, and conditions under which such service is to be rendered must be determined by the wisdom of men and not by Nature herself." (ibid. )

Thus, positive law is nothing more than an implementation of the natural law that must vary with the changing circumstances and conditions of social life.

Essentials of Natural-Law Doctrine. The eternal law is the plan of the divine providence governing the cosmos, man, and matter, both animate and inanimate. It is the ordering wisdom of God. Natural law is said by Thomas to be "nothing else" than a rational participation of this divine ordering wisdom. This is to say that natural law is defined by its metaphysical and theological character. The preceptive commands of the natural law derive their normativity from being rooted in the perfect being, good, and truth of God which are not admixed or limited by any potency or imperfection whatsoever. For St. Thomas "command" is an act of the intellect; thus, the precepts of the natural law while willed by God always are conformed to the divine wisdom and goodness. Natural law is that part of the eternal law that is properly applicable to man alone, although it may be spoken of lower creatures by a kind of analogy—by "participation and similitude."

Human reason is a "measured measure": it takes its measure from the objective ordering of human nature to the order of ends that perfects it, and thus consequently reason is enabled to be the rule and measure of right action. Yet the natural law is promulgated by God through instilling it in man's mind so as to be known—it is not "self-promulgated" by our knowing, but rather is promulgated by its being divinely instilled in the rational nature of man so as to be naturally known. Hence the natural law meets the requisites of law generally: it is promulgated by God who has authority over the commonwealth of being, and is for the sake of the common good (God being the extrinsic common good of the whole universe). Natural law is natural in several important senses. First, it is said to be natural because we are naturally subject to it, quite apart from any choice. The end, and indeed the whole hierarchy of ends, which perfects human nature is not among those things that are subject to human dominion. We may affect our motion to the end by our choice of means, but we can neither alter our natural ordination to happiness, nor alter that in which this happiness naturally consists. Second, the law is called natural because our initial awareness of the law—as an epistemic matter—derives from our awareness of our natural ordering to ends. For example, we do not choose to be creatures who thirst in the desert, who are lonely when lacking friends, who are confused when lacking truth: we simply are such creatures, and the initial awareness of the ordering of human nature to the whole hierarchy of ends is natural rather than received merely by book learning, or by oral tradition. Third, the natural law is said to be natural as contrasted with the lex nova of supernatural grace that governs the higher ordering of human nature to an end that transcends any natural end, namely, the essentially supernatural beatific vision of God.

Also fundamental to St. Thomas's philosophy of natural law is the distinction between the speculative reason and practical reason (see cognition, speculative-practical). Speculative knowledge pertains to that which cannot change and is sought for the sake of knowing itself, whereas practical knowledge pertains to the changeable (objects of deliberation) and is sought for the sake of action. Yet practical knowledge presupposes prior speculative adequation toward the ends of human living. Though virtuous action is conformed to right appetite, right appetite itself presupposes knowledge of the end. The natural sciences are the work of the speculative reason; natural law, on the other hand, is a "dictate of the practical reason." "The precepts of the natural law are to the practical reason what the first principles of demonstrations are to the speculative reason, because both are self-evident principles" (Summa theologiae 1a2ae, 94.2). Just as being is what first falls under the apprehension of the speculative reason, so good is what first falls under the apprehension of the practical reason. The practical reason is directed to action, and every agent acts for an end that it regards as good. Hence the first principle of the natural law is that good is to be done and evil is to be avoided. "All other precepts of the natural law are based upon this: so that whatever the practical reason naturally apprehends as man's good or evil belongs to the precepts of the natural law as something to be done or avoided" (ibid. ).

Both the speculative and the practical reason attain the same degree of certainty with regard to first principles, but not with regard to the conclusions drawn from these principles. St. Thomas makes a point of this difference: "For, since the speculative reason is concerned chiefly with necessary things, which cannot be otherwise than they are, its proper conclusions, like universal principles, are true without fail. The practical reason, on the other hand, is concerned with contingent matters, which are human actions; consequently, although there is some necessity in its general principles, the more we descend to matters of detail the more frequently we encounter defects" (Summa theologiae 1a2ae, 94.4). Thus, for St. Thomas, it is vain to expect the same certainty in judicial decisions as in the physical sciences, but it would be rash to deny altogether the existence of universal principles that constitute the natural law.

Content of Natural Law. St. Thomas defines the natural law as the participation of the eternal law in the rational creature (ibid. 1a2ae, 91.2). It should be noted, however, that the participation to which he refers is limited and defective. "Human reason cannot have a full participation of the dictate of the Divine Reason, but according to its own mode, and imperfectly" (91.3 ad 1). In other words, man's natural participation of the eternal law consists in the knowledge of certain general principles, not of every particular decision relating to an individual case. Since generality admits of infinite degrees, the precepts of natural law cannot be numbered exactly. All such precepts are instantiations of the primary precept that good is to be done and evil avoided. They are not simply deduced from the first precept of law (primum preceptis legis ) that good is to be done and pursued and evil to be avoided, because this first premise is insufficiently determinate to serve such a role. This first precept of law embraces the whole dynamic ordering of man to the good and to the entire hierarchy of ends. Thus the natural law is made effective through virtues, the various habitus whereby one acts promptly, joyfully, and well, with respect to the end. As conclusions from the natural law become more and more remote, they shade off into the sphere of human law; therefore, there can be no clear-cut borderline between natural and human law. That is why St. Thomas maintains that the natural law can be changed by way of addition and is capable of unlimited growth (94.5).

For St. Thomas all the moral precepts of the Old Law pertain to the natural law in the sense that all are consonant with reason, although all do not pertain to natural law in the same way (100.1). Of the Ten Commandments the first three (according to the enumeration in common use among Catholics) pertain also to divine positive law inasmuch as man needs instruction by God to enable him to perceive their consonance with reason (it is a matter of natural justice that man owes public worship to God, and hence acceptance of whatever divine revelation dictates may be said to be commanded by the natural law as well as by the divine law). The remaining seven precepts pertain to the natural law not only in the sense that they are consonant with reason, but also inasmuch as this consonance does not require revelation to be known. The latter precepts are among the most proximate conclusions from the primary principles. "Honor thy father and thy mother" is a concretization of "good is to be done," and the remaining six Commandments are concretizations of "evil is to be avoided." All are among those things "that the natural reason of every man, of his own accord and at once, judges should be done or avoided" (ibid. ). Other precepts of the Old Law pertain also to natural law, even though their rightness is not immediately apparent. An example is "Honor the person of the aged man" (ibid. ), which is among the more remote conclusions. For St. Thomas, the two most immediate conclusions deducible from the primary precept are: "Thou shalt love the Lord thy God" and "Thou shalt love thy neighbor"; all the precepts of the Decalogue are referred to these (100.3 ad1).

Besides moral precepts, St. Thomas mentions two other types, namely, the ceremonial and the judicial (or juridical). The ceremonial precepts are determinations of the natural law whereby man is directed to God, whereas the juridical precepts are determinations of the natural law whereby man is directed to his neighbor. Unlike conclusions, determinations belong not to the integral body of the natural law but to positive law, whether divine or human. There is no question that the ceremonial precepts, which deal with the ways and forms of worship, belong to divine positive law. As to the judicial or juridical precepts, although most are determinations of the natural law, some may be conclusions (however remote) of the natural law, and therefore constitute an integral part of it.

Determination vs. Conclusion. The distinction between a conclusion and a determination is clearly expressed by St. Thomas: "The law of nature has it that the evildoer should be punished; but that he be punished in this or that way, is a determination of the natural law" (Summa theologiae 1a2ae, 95.2). Similarly, it is a conclusion of the natural law that he who injures another should compensate him; but exactly how to compensate him is a determination that can be laid down by positive law and is subject to change. For instance, the following law is found in Exodus: "When a man steals an ox or a sheep and slaughters or sells it, he shall restore five oxen for the one ox, and four sheep for the one sheep" (21.37). Such a prescription is certainly not a part of the natural law because it is not evident to natural reason. The case is different with the following: "You shall not molest or oppress an alien, for you were once aliens yourselves in the land of Egypt" (Ex 22.21). "You shall not wrong any widow or orphan" (22.22). "The innocent and the just you shall not put to death" (23.7). "Never take a bribe, for a bribe blinds even the most clear-sighted and twists the words even of the just" (23.8). Whether these are referred to as moral or juridical precepts, they are conclusions of the natural law whose rectitude is apparent to man's reason.

While determinations form no part of the natural law, their proper function is to implement the natural law. An instance of this is found in the modern law of restitution. The natural law demands that one who is unjustly enriched at the expense of another should restore whatever benefits he has derived from his unjust act. In order to implement this dictate of natural reason, American judges have invented the fiction of "constructive trust." As Justice B. N. Cardozo has put it, "When property has been acquired in such circumstances that the holder of the legal title may not in good conscience retain the beneficial interest, equity converts him into a trustee" (225N.Y. 380, 386). Judge C. S. Desmond has said that "a constructive trust will be erected whenever necessary to satisfy the demands of justice. Since a constructive trust is merely 'the formula through which the conscience of equity finds expression,' its applicability is limited only by the inventiveness of men who find new ways to enrich themselves by grasping what should not belong to them" (299 N.Y. 27). Here positive law serves the natural law as a faithful and efficient handmaid.

The cases of constructive trust also furnish an apt illustration of the function of synderesis, conscience, and prudence and their mutual workings with respect to natural law. It is the role of synderesis to perceive the principles of natural law: the principles here involved are that no one should enrich himself unjustly at the expense of another and that, if he does, he should be required to restore the benefits to the latter. It is the role of conscience to recognize that, in this or that particular case, a particular party is unjustly enriched. Finally, it is the role of prudence to devise or choose the best means of implementing the demands of justice. The interworkings of these functions in the jurist are seen at their best in the courts of equity, which had their origins in the English chancellor, who was at the same time "the keeper of the king's conscience." No doubt many of the chancellors were steeped in the Christian tradition of the natural law.

Effects of Natural Law. Among the principal effects of the natural law are its obligation and its sanction. The obligation of natural law arises from two sources: (1) primarily, the ordering wisdom of God; (2) secondarily, the essential order of things as naturally measuring the human reason, which reason is then fitted to be the measure of human acts. Of all creatures, man alone is endowed with a moral law and with reason to discern its obligations. He is aware that it is precisely this ingrained moral law that distinguishes him from the lower animals. It is the badge of his natural nobility. To obey the dictates of this moral law is to be true to his own nature. To play false to his nature, on the other hand, is to fall lower than brute animals, who, although devoid of rationality and a sense of obligation, follow instinctively the laws of their nature.

Regarding the provenance of law's obligation from God, Immanuel Kant observed: "Two things I contemplate with ceaseless awe; The stars of heaven, and man's sense of law." This expresses more than a cosmic emotion that springs from the feeling of harmony between macrocosm and microcosm; the awe of which Kant speaks comes also from an awareness, at least implicit, of God the Supreme Lawgiver. When one is aware that the same God who established the order of the universe also instituted the internal order of man's nature, his vision is like that of David, who saw the whole universe radiant with the glory of God (Ps 18.24). The laws that the Lord has written in man's heart, however, convey more than Kant's categorical imperatives; they are also a perennial delight. This high vision defies all human expression and imagination; yet one sure effect of it is that man's desire and will are "revolved, like a wheel which is moved evenly, by the love which moves the sun and the other stars" (Dante, Paradiso, 33.142).

Sanction. Only a portion of the natural law can be adopted and enforced by human law with its external sanctions. To take a simple instance, human law can forbid adultery with penal and civil sanctions. But Christ said that "anyone who so much as looks with lust at a woman has already committed adultery with her in his heart" (Mt 5.28). This, too, belongs to the natural law; but human law is too clumsy of an instrument to take cognizance of such cases. Does this mean that the natural law is without a sanction of its own? If so, it would be ineffectual. In fact, however, natural law is more effective than human law. In the first place, virtue is its own reward; and vice, its own punishment. One simply cannot be virtuous without being happy, nor can one sin without being miserable.

The end proportioned to man's nature is fulfillment through practical and speculative virtue, although in this ordering of creation, nature is further ordered to the beatific end and hence all natural ends are further ordered to beatitude. Natural law entails being entirely true to the actual ordering of human nature. virtue promotes this cause, whereas vice frustrates it. As a Chinese proverb has it, "there is no happiness like that of doing good." And it is equally true that there is no hell like sinning. Herein lies the intrinsic sanction of the natural law. Again, natural law is sanctioned by the law of spiritual causality: one reaps what one sows. "Do men gather grapes from thorns, or figs from thistles? Even so, every good tree bears good fruit, but the bad tree bears bad fruit" (Mt 7.16–17). In saying this, Christ merely restated part of the natural law. For it does not take a special revelation to know that "God's mill grinds slowly but surely," as the Greeks observed. Lao Tze put the same truth in this way: "Vast is Heaven's net; /Sparse-meshed it is, and yet / Nothing can slip through it." Finally, since God is supremely just, real virtue (especially when hidden) will not go unrewarded any more than deliberate and unrepented viciousness will go unpunished. The Christian law of mercy does not abolish this fundamental law of divine justice: on the contrary, it reveals the nature of this justice more fully, gives man a chance to begin anew, calls him to repentance, and enables him to meet its obligations. Christ did not come to destroy the natural law, but to fulfill it (cf. Mt 5.17). As a consequence of His coming, the Christian's obligation to fulfill the law has increased immeasurably. For unless his justice exceeds that of those who know not Christ, he shall not enter the kingdom of heaven.

Awareness of Natural Law . It has already been stated that our inceptive knowledge of the natural law proceeds not merely by book learning or custom, but from natural awareness of the ordering of human nature itself. Its primary precept of pursuing good and avoiding evil and its immediate conclusions are indemonstrable; yet they are self-evident principles of the practical reason. Thus it is not merely or primarily by logical or empirical reasoning that the first precepts of the natural law are known, but by the natural habitus called "synderesis." Synderesis is a habit of the reason; it is not an all-purpose moral intuitionism along the lines of G. E. Moore, but rather a habitus of moral light through whose act nature inclines to good and warns from evil. Its act presupposes that knowledge required for the intelligibility of the precepts involved. Conscience, on the other hand, is the act that applies this general knowledge to a particular situation. If, for instance, a person sees a little child crawling into a well, he sees immediately that it is his duty to hold the child back and save its life, no matter whose child it may happen to be. This awareness is the working of conscience. If, moreover, one fails to rescue the child and it is drowned in the well, he feels remorse. This, too, is the working of conscience, which, having given the command in the first instance, applies its sanction for failure to carry it out. Synderesis is the natural habit whereby we are disposed to know the law, and conscience is the act of its application to particular cases.

Since the elementary principles of the natural law are innate in human nature, evidences of it appear even in primitive law. Yet there is a growth in the content of natural law with the progress of civilization. As the human mind becomes more and more enlightened, it becomes capable of devising new and more effective methods of ascertaining the truth and implementing the natural law. Similarly, the human heart, refined by the developments of arts and letters, grows in sensitivity to new values and needs of humanity; as a consequence, it prompts legislators and judges to draw new conclusions from the first principles of the natural law. In this way, our awareness of naturally just claims has been enhanced in the course of history, as the justice of these claims is recognized but not made by human law. One example is the development of moral consensus regarding the evil of the institution of chattel slavery. Another is the growing moral awareness of the evils that may ensue upon the new technology of biological cloning technologies that applied to man deny the dignity of the human person.

Divine Revelation and Papal Teaching. The natural law is independent of any divine revelation. Its first principles are common to all men and are not the exclusive possession of the Judeo-Christian tradition. However, there can be no question that Christian writers have been greatly aided by revelation in their discovery of the natural law and natural rights. This point was brought out clearly by Chancellor James Kent in Wightman v Wightman (Chancery Court of New York, 1820. 4 Johnson Ch.343). Pronouncing the nullity of the marriage of a lunatic, Chancellor Kent said: "That such a marriage is criminal and void by the Law of Nature, is a point universally conceded. And, by the Law of Nature, I understand those fit and just rules of conduct which the Creator has prescribed to Man, as a dependent and social being; and which are to be ascertained from the deductions of right reason, though they may be more precisely known, and more explicitly declared by Divine Revelation."

It is truly characteristic of her catholicity that the Church has persistently "affirmed the value of what is human and is in conformity with nature," notwithstanding her teaching on original sin. pius xii, the greatest jurist among the modern popes, never tired of speaking of the natural law. In his address to members of the International Convention of Humanistic Studies (1949), he observed: "She [the Church] does not admit that in the sight of God man is mere corruption and sin. On the contrary, in the eyes of the Church, original sin did not intimately affect man's aptitudes and strength, and has left essentially intact the natural light of his intelligence and his freedom. Man endowed with this nature is undoubtedly injured and weakened by the heavy inheritance of a fallen nature, deprived of supernatural and preternatural gifts. He must make an effort to observe the natural law—this with the powerful assistance of the Grace of Christ—so that he can live as the honor of God and his dignity as man require." Starting from the essential nobility of human nature, the pope went on to say:

The natural law here is the foundation on which the social doctrine of the Church rests. It is precisely her Christian conception of the world which has inspired and sustained the Church in building up this doctrine on such a foundation. When she struggles to win and defend her own freedom, she is actually doing this for the true freedom and for the fundamental rights of man. In her eyes these essential rights are so inviolable that no argument of State and no pretext of the common good can prevail against them…. It cannot touch theserights for they constitute what is most precious in the common good.

Pius XII saw that the chief source of confusion and disorder in the 20th century lay in the deliberate abandonment of the natural law. In his very first encyclical, Summi Pontificatus, he asserted: "One leading mistake We may single out, as the fountainhead, deeply hidden, from which the evils of the modern state derive their origin. Both in private life and in the state itself, and moreover in the mutual relations of race with race, of country with country, the one universal standard of morality is set aside; by which We mean the natural law, now buried away under a mass of destructive criticism and of neglect." This has become possible because in some states, at least, the pernicious doctrine of state absolutism has prevailed, with the result that the state has actually usurped the position of God. When the Author of the natural law is set aside, there can be no room for the natural law, which, as Pius XII insisted, "reposes, as upon its foundation, on the notion of God, the Almighty Creator and Father of us all, the Supreme and Perfect Law-giver, the wise and just Rewarder of human conduct."

Bibliography: j. c. h. wu, Fountain of Justice (New York 1955). j. messner, Social Ethics: Natural Law in the Modern World, tr. j. j. doherty (new ed. St. Louis, Mo. 1964). m. t. rooney, Lawlessness, Law, Sanction (Washington, D.C. 1937). Notre Dame Univ., Natural Law Institute: Proceedings v. 1–5 (1947–51). j. d. wild, Plato's Modern Enemies and the Theory of Natural Law (Chicago, Ill. 1953). p. j. stanlis, Edmund Burke and the Natural Law (Ann Arbor, Mich. 1958). a. g. cicognani, Canon Law, tr. j. o'hara and f. brennan (2d ed. Westminster, Md. 1947; repr. 1949). j. maritain, Man and the State (Chicago, Ill. 1951); An Introduction to the Basic Problems of Moral Philosophy, tr. c. n. borgerhoff (Albany, N.Y. 1990). y. simon, The Tradition of Natural Law, tr. v. kuic and r. j. thompson (New York 1992). r. mcinerny, Ethica Thomistica (Washington, D.C. 1997); Aquinas on Human Action: A Theory of Practice (Washington, D.C. 1992). r. hittinger, "Natural Law and Catholic Moral Theology," in A Preserving Grace, ed. m. cromartie (Washington, D.C. 1997); "Natural Law as Law," American Journal of Jurisprudence 39 (1994) 1–32.

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CONTEMPORARY THEOLOGY AND PHILOSOPHY

One distinction that is indispensable for understanding the place of natural law in contemporary theology and philosophy is that between the ontology of natural law, or its existence, and the epistemology of natural law, or the knowledge of principles that may be said to constitute it. It seems from the dissent that takes place in contemporary discussions of natural law that there is more disagreement over the epistemology than there is over the ontology.

Protestant Criticisms. S. E. Stumpf suggests such a distinction when he asserts that contemporary Protestant thought is fundamentally critical of natural-law theory, although it does not repudiate the theory completely. For the Protestant, the disagreement arises from a philosophy that is based on the accessibility of nature to man's rational powers, an accessibility that he is unwilling to admit. For him the "Catholic" natural law is associated with the Thomistic notion of the analogy of being, according to which the natural law is defined in terms of the eternal law that exists in God. The promulgation of this law, as has been explained above, is made in the rational nature of man. The application of its principles, whether primary, secondary, or tertiary, to contingent situations is made by the consciences of men in their practical prudential judgments. For many Protestants, this explanation places too much importance on stable natures and rational powers, and not enough upon the ambiguity in every moral situation. Reinhold niebuhr's criticism of what he calls "classical, catholic, and modern natural law concepts" proceeds along these very lines. He insists that these concepts do not allow for the historical character of human existence because they are radicated in a classical rationalism that did not understand history. These concepts, for Niebuhr, do not appreciate the uniqueness of the historical situation or the accretions that came into the definition of natural law through history. The general principles are too inflexible, and the definitions of these general principles are too historically conditioned. Niebuhr does not deny an "essential" nature of man, but the profoundest problem for him is the historical elaboration of man's essential human nature, on the one hand, and the historical biases that have insinuated themselves into the definition of that essential human nature, on the other.

A second criticism, for Niebuhr, is the tendency in the classical theory to make the law of love an addition to the law of obligation, with the result that the one deals with the determinate possibilities and the other the indeterminate possibilities of good. In his view, clear lines between determinate and indeterminate possibilities cannot and should not be drawn. Niebuhr illustrates this by saying that justice is an application of the law of love for which the rules are not absolute but relative. All such rules are applications of the law of love and do not have independence apart from it. They would be autonomous only if they were based upon an "essential" social structure, and there is no definition of such an essential structure of community, except the law of love. Stumpf makes this the cardinal point of criticism between the Protestant and Catholic conceptions of natural law. The ground of ethics is love even for the natural man and such love is the fulfillment and completion of the law. Love and grace are not dimensions of the supernatural order only, but justice is infused and transfigured by love. The Protestant conception, then, is fundamentally the confrontation of man with the God of judgment and love commanding him, not through the mediation of abstract primary, secondary, and tertiary principles, but subjecting him to the single imperative of an undifferentiated and naturally indefinable love. No law mediates between man and God— only love—and this love is the natural law for the very reason that love is the law of man's essential human nature, which passes otherwise undefined. The metaphysical structure of reality, and the teleological structure of nature, are each set aside as at best merely provisional and awaiting reformulation in the new law.

Different Views of Reason . It should be seen at once that all Catholic and many Protestant theologians would admit an essential human nature, but even there the word "essential" demands quotation marks and precise refinements of meaning. R. E. Fitch, dean of the Pacific School of Religion, is quoted in a footnote of an article by A. R. Jonsen "Arguing Ethics" (Homiletic and Pastoral Review [Jan. 1964] 302), in which reference is made to two entirely different views of reason that are possible in any discussion of natural law. For the Catholic, the stress is on the reason that is Aristotelian, classical, ordered, and universal; for the Protestant, the emphasis is on the reason that is individualistic, inquiring, and experimental. Fitch says that both are needed, and no one will question that conclusion. The combination of the two stresses might be assisted by the suggestive use of the phrase "prismatic analysis" in connection with the formation of the practical prudential judgments of the individual conscience. It can readily be seen how the most general principles of law passing through this individual human prism receive all the colorations, the ambiguities, the obstacles, and the helps from the particular existential historical moment of their passage. For the person who leans toward a somewhat complete situationalism, no law passes through the human prism but the law of love; anything else that he might designate as law is not exigent and obligatory, but guiding and tentative, provisional and contingent. The position of the moderate situationalist is one that appreciates both the imperative of obligation and the imperative of love, while giving full validity to all the contingent factors in the ambiguous ethical situation. Between the divine transcendence and the ever-changing human situation, J. C. Bennett places the "middle axioms," which seem to be employed to mediate between more general norms and the unique structural situation. Niebuhr speaks of "enduring structures of meaning and value" that must be assured a valid role in the ethical choice. Will Herberg finds some clarification of these conceptions of the "enduring structures of meaning and value" of Niebuhr and the "middle axioms" of Bennett by citing Edmund burke, who has this to say about natural rights:

These metaphysical rights, entering into common life, like rays of light which pierce into a dense medium, are … refracted from a straight line… [and] undergo such a variety of refractions and reflections that it becomes absurd to speak of them as if they continued in the simplicity of their original direction. ("Conservatives, Liberals and the Natural Law, II," National Review, June 19, 1962)

Philosophical Presuppositions. The fundamental disagreement on natural-law theory, therefore, is rooted in philosophical presuppositions on the nature of law, on the nature of man, on the very meaning of "natural." The signification of a theory of natural law for the Roman Catholic, the Protestant, and the secular humanist will be conditioned from the very start by these philosophical presuppositions. In fact, many theological disagreements find their ultimate sources of division in philosophical premises. To those inclined to regard metaphysical knowledge as not so respectable a knowledge as that of the empiro-logical sciences, the intelligibility of nature, of man, of law, and of God will be regarded with increasing skepticism. All these obstacles that are profoundly philosophical will make difficult the acceptance even of the existence of natural law at its barest minimum. When, in addition to the difference in philosophical presuppositions, the differences in theology concerning the nature of original sin and its consequences for the nature of man are studied, it can be more clearly seen why natural law for the Catholic has been a dialectical tool. It stands to reason that he can employ this tool effectively only if he constantly appreciates these philosophical and theological differences.

Catholic Theology. Natural law has understandably been of interest to the Catholic theologian, who has always interested himself in the mutual relation of reason and faith and is convinced that God operates in history through the natures of things and especially through the nature of man. He presumes that man's nature has not been totally deformed by original sin and that his intellect and will are capable of constructing a natural theology and a moral philosophy that are valid and complemented by supernatural theology and a moral theology. In light of this judgment, he does not hesitate to study the essential ordering of human nature and to discover certain conformities and deformities with respect to it. Unfortunately, the principal obstacle to the acceptance of natural law in modern times is the mistaken notion that this law belongs to the Catholic Church and no other. Yet it is undeniably true that the Catholic Church has been the most vigorous defender of natural-law theory in areas ranging from property rights to contraception and from the problems of medical ethics to those of nuclear warfare.

With the gradual lowering of moral standards, however, the Church has given more of her magisterial attention to the claims of nature and justice. J. fuchs, in Lex Naturae zur Theologie des Naturrechts (Düsseldorf 1955, 9–12), shows that since the reign of Pius IX the term "natural law" has been employed with increasing frequency in the documents of the Church. The term was constantly mentioned in the allocutions and discourses of Pius XII on the issues of peace and war, on political organizations, and on the obligations of the many professions, especially medicine and law. Yet the fact that the Church has been concerned with defending the natural and to relate it to the supernatural does not make the natural itself supernatural. The natural law is the basis and foundation for the supernatural code of ethics found in moral theology, whereas the additional evidence for certain forms of ethical conduct derives from biblical sources and from tradition. At times the papal documents refer to elevated human nature, to human nature supernaturalized by grace; where this is done, however, the texts are clear, and such citations do not permit a reader to conclude that the argument from reason has been so substantially undermined that only Catholic faith provides a valid and cogent ground for ethical conduct. The interrelation between faith and reason on the precise question of the probative value of evidence from natural law is most certainly ground for debate among Catholic theologians, but no one of them would deny completely all probative value and all cogency to a natural-law argument.

This issue has received heightened attention as a result of the discussions of the normative relation of nature and grace ensuing after the publication of Henri de lubac's famous Surnaturel (Paris 1946). The issue is whether the integrity of the natural order does not require a natural end for man (granted that this end is no longer actually the ultimate end, and that in the order of divine providence that this end is further ordered to the beatific finis ultimus ). De Lubac argued the impossibility of any natural end for man proportioned to human nature itself. This denial has seemed to many Thomists to constitute a denial of the relative integrity and autonomy of the natural order. St. Thomas Aquinas expressly held that man could have been created in a purely natural state, (e.g., Quod. I, q. 4, a.3, resp.) and that if man had been so created, the deprivation of supernatural beatitude would not constitute a punishment as now it does (De malo, q.1, art. 5, ad 15). This clearly implies in St. Thomas's teaching that there is a felicity or end proportionate to man's nature, distinct from the further ordering in grace to which man is now actually called and toward which natural ends are now ordered. In the years following Surnaturel, the works of Hans Urs von balthasar and those by thinkers of the communio school who radicalize this position of de Lubac (e.g., David Schindler), as well as of some by Greek Orthodox theologians (John Zizioulas) have brought these questions further into the foreground. The Thomistic teaching persists in exerting a powerful influence over the formulation and understanding of the issue of natural law within Catholic theology.

Charge of Vagueness and Ambiguity. A fundamental criticism, especially from circles outside the Church, points to the difficulties in the presentation of the natural law; the presentation seems to be indeterminate and unsatisfactory, at least as its defenders formulate it. Again, the evidence that the defenders of natural law adduce may not be cogent in the light of differences in moral beliefs and practices at different times and places. N. Bobbio, in "Quelques arguments contre le droit naturel" [Le droit naturel (Paris 1959) 175–190], suggests this criticism when he remarks that philosophers are inclined to deny that the natural law is natural, whereas legal scholars tend to deny that it is a law. The response for the Thomistic supporters of natural law is that it is both natural and genuinely a law, that it is verifiable as natural and valid in an authentic meaning of law. Robert Gordis points out the dilemma of those who stand outside the dominant tradition of natural law but are sympathetic to its value. He refers to Robert M. Hutchins's observation that natural law appears to many to be "a body of doctrine that is so vague as to be useless or so biased as to be menacing." For such persons the vagueness and ambiguity of terms such as "nature" and "natural" have always been a part of the history of ideas. For them the opinion of Leslie Stephens may not be the cynical exaggeration that it is for others: "Nature is a word contrived in order to introduce as many equivocations as possible into all theories, political, legal, artistic or literary, into which it enters." Critics of natural law are ready to add to the catalog of meanings given to "nature." D. G. Ritchie, in Natural Rights (2d ed. [London 1903] 20 47), has a chapter "On the History of the Idea of Nature in Law and Politics"; Erik Wolf's Das Problem der Naturrechtslehre (Karlsruhe 1955) gives nine meanings for "nature" in the context of natural law alone; and Philippe Delhaye's Permanence du droit naturel ([Louvain 1960] 9–21) has an introduction that explains at least 20 meanings of "nature."

This testimony to the vagueness and ambiguity of the term "nature" was not unknown to the proponents of natural law from their examinations of its meaning for the Stoics, John Duns Scotus, Bishop J. Butler, Hume, and Rousseau. Yves Simon commented on this difficulty in The Tradition of Natural Law. He considers the confusion of ideological aspiration with philosophic contemplation of the natural law to have led to the tendency to suppose that natural law can decide "with the universality proper to essences, incomparably more issues than it is actually able to decide." He notes the tendency of certain teachers to treat as matters of natural law issues that demand "treatment in terms of prudence" and contends that such exaggerated claims in behalf of natural law will tend to engender "disappointment and skepticism" as well as that contempt naturally felt for sophistry (The Tradition of Natural Law [New York 1992] 23–24).

Yet the proponent of natural law does insist that human rational nature is subject to a normative order in which may be verified the essential features of law: it is promulgated by God from creation, it is prescriptive and preceptive insofar as providing reasons to do and not to do, and it is for the sake of the common good, issued by the One who is the governor of the entire commonwealth of being. That in the order of knowing we are aware of moral truths prior to being aware of these as being law merely establishes a distinction between the order of discovery and the order of being. Accusations of ambiguity arguably betray a deontological tendency that would obviate the role of virtue in the prudential articulation of the implications of the natural law. The study of the human virtues and natural law are essentially complementary, for in its classical formulation natural law is made effective in and through human virtues—active potencies or dispositions for acting strongly and joyfully toward the good.

Contributions of Anthropology. As helps in this analysis, tradition, revelation, and authority are implied by the actual further ordering of nature to grace, as well as by the purely natural calling of human persons to the extrinsic common good of the universe (God), of justice and truth, of the political state, and even of the family. The traditional elaboration of natural law must also be supplemented by materials from cultural anthropology and from all the sciences insofar as they do not stray from their formal objects. Thomistic ethicians have an important function in the incorporation of these contributions. In "Human Evolution: A Challenge to Thomistic Ethics" [International Philosophical Quarterly 2 (1962) 50–80], Charles Fay shows how some of the changes resulting from man's biocultural evolution may so transform the relation between man and nature (e.g., atomic energy, polymer chemistry) that certain acts may receive a different moral evaluation. R. H. Beis, in "Some Contributions of Anthropology to Ethics" [Thomist 28 (1964) 174–224], considers the several advantages that a knowledge of anthropology holds for the ethician and discounts the anxiety of those who consider that anthropology supports only ethical relativity. In fact, Beis finds contradictions in the position of anthropological ethical relativity when it attempts to assume values of its own.

The philosopher-theologian, interested in a firm foundation for his natural-law position, is not unconscious of the advances in the contributions of anthropology to ethics. He is encouraged to recognize that anthropology does not scientifically establish ethical relativity. However, it is appropriate to the study of natural law to clarify the distinction between what is universal and invariable in human nature and what is conditioned by the circumstances of cultural development.

Other Disciplines. It may be overly optimistic and naïve to consider that there can be more fruitful agreement on natural law by further clarification of the two aspects of human nature, the absolute and invariable, and the relative and conditioned. If the former has been emphasized in the past, the latter is not being ignored in the present. This is especially so in contemporary discussions of natural-law jurisprudence.

Again, the modern ethician and theologian who introduces references to natural law in medical morality or in sexual ethics does not ignore scientific facts that are relevant. The discussion of the licit use of anovulants in certain pathological conditions raises many questions for whose answer the ethician is ready to accept all the scientific help he can get. The modern ethician and theologian of natural law takes into account all relevant scientific data and frequently finds the lack of consensus not among ethicians and theologians, but among scientists themselves. Where lack of consensus among practitioners of the sciences flows from an inadequate philosophy of nature that generates confusion about and obscures natural teleology, substantial nature, or other essentially philosophic elements, such lack of consensus implies only that those in question should educate themselves. But where genuine differences within a field itself—as opposed to precursory differences—are at issue, the natural lawyer must await clarification. One necessity thus revealed is that of distinguishing ideologically driven errors and confusions flowing from scientism from the more limited methods of positive science.

Role of the Church. To avoid such confusion, the Catholic Church has always maintained that the natural law is an object of its teaching authority and that its guidance is necessary for an adequate knowledge of the natural law. This is not merely a pragmatic decision, but a clear mandate implied by the further ordering of all natural ends to the beatific finality. Just as the natural law governs man's normative ordering toward the ends proportionate to his nature, so divine law governs the order toward that supernatural end which is disproportionate to any finite nature. Gerald Kelly, SJ, refers to the moral (not physical) necessity of revelation in this regard. In other words, the guidance of the Church is a practical, or moral, necessity for obtaining an adequate knowledge of the natural law. When it is considered that the natural law is sufficiently promulgated, according to its proponents, if there is promulgation of its primary and secondary precepts in such a way that no one can be invincibly ignorant of these, this alone might be thought to leave so much to be discovered by man himself that, without the assistance of some guide and authority, his search would not be very satisfactory. Of course, this by itself might only indicate that the further implications of the natural law are not effortlessly known by all, which is indeed true even of the natural order of the physical cosmos, and hence is all the more true of man's participation in the eternal law. The need for grace is not unique to this area of human striving, either—any integrally right use of human capacities will require grace to be ordered to the due end of beatific finality. Nonetheless, the harm done to human affectivity and inclination by sin, and the higher ordering of all natural ends to the beatific finality, alike indicate the need for guidance from the custodian of divine revelation to assure correct understanding of the natural law.

St. Thomas makes clear (Summa theologiae I-II, q. 85, a. 1, resp.) that nature is, in part, destroyed by original sin. He identifies three senses of human nature: 1) the principles and properties of human nature; 2) the natural inclination to virtue; and 3) that gift of original justice conferred upon the first parents of the human race. He states that the third (the gift of original justice) is destroyed by sin; the second (the natural inclination to virtue) is diminished (but not utterly destroyed) by sin; and the first (the principles and properties of human nature) is neither destroyed nor diminished by sin. Because the root of our natural inclination to virtue is the rational nature, this inclination cannot be wholly extinguished. Knowledge of the natural law and its implications is always in principle naturally possible. The natural tendency of the rational creature to God cannot wholly be eradicated. But because the natural inclination to virtue is diminished by sin, full knowledge of—and robust conformity to—the natural law implies the aid of revelation and grace. This is especially so inasmuch as the diminishment of natural inclination by sin implies diminished natural vigor in the pursuit of the good—whereas it is those who vigorously strain toward the good who are most able to discern its implications.

See Also: nature; man; law; law, philosophy of.

Bibliography: c. w. kegley and r. w. bretall, eds., Reinhold Niebuhr: His Religious, Social and Political Thought (New York 1956). Handbook of Christian Theology, ed. m. halverson and a. h. cohen (New York 1958). j. cogley et al., Natural Law and Modern Society (Cleveland, O.H. 1963). l. r. ward, "Natural Law in Contemporary Legal Philosophy" Proceedings of the American Catholic Philosophical Association 33 (1959) 137–143. s. bertke, The Possibility of Invincible Ignorance of the Natural Law (Catholic University of America Studies in Sacred Theology 58; Washington, D.C. 1941). r. d. lumb, "Law, Reason and Will," Philosophical Studies 10 (1960) 179–189. g. p. grant, Philosophy in the Mass Age (New York 1960). j. maritain, Science and Wisdom, tr. b. wall (London 1940); An Introduction to the Basic Problems of Moral Philosophy, tr. c. n. borgerhoff (Albany, N.Y.1990). y. simon, The Tradition of Natural Law, tr. v. kuic and r. j. thompson (New York 1992). r. mcinerny, Ethica Thomistica, rev. ed. (Washington, D.C. 1997); Aquinas on Human Action: A Theory of Practice (Washington, D.C. 1992); The Question of Christian Ethics (Washington, D.C. 1990). r. hittinger, "Natural Law and Catholic Moral Theology," in A Preserving Grace, ed. m. cromartie (Washington, D.C. 1997); also, "Natural Law as Law," American Journal of Jurisprudence 39 (1994) 1–32.

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NATURAL LAW

Natural Law is a long-standing and widely influential theory in ethics and legal philosophy. Because of its long and varied history, and the diversity of definitions of the term "natural," it is somewhat difficult to summarize exactly what makes a position or methodology one of natural law—at least in such a way as to neatly include all the positions and methodologies that have gone by that name. In attempting to establish a broad set of characteristics such a theory would have to possess in order to be considered natural law, it is useful then to look at the historical development of paradigmatic theories, paying attention to David Hume's advice that when trying to understand a discourse that employs the concept of "nature," we must consider what the concept is contextually being opposed to, and "the opposition will always discover the sense, in which it is taken" (Hume 2000, p. 305, n.).

In general, we can say that the traditional notion of natural law has held to the following four propositions: (1) morality is ultimately real and objective and is not relative in its primary truths to culture, subjective taste, or social agreement; (2) morality is somehow grounded in human nature, which is a specific part of the general order of nature, and is crucial for human happiness and flourishing; (3) the normative force and obligatoriness of morality is somehow the result of this grounding and may be understood using the terminology associated with a legal code; (4) the application of reason in examining human nature, and to some extent general nature, provides evidence for the specific content of our moral obligations.

Some theories, especially contemporary ones, may not clearly fit the pattern of this list. However, this speaks to a criticism that some recent "natural law" theories are not really natural law theories at all. It is in reference to the sort of positions specified above that such criticisms are made. There is also a problem in producing such a list as to whether reference should be made to God as a divine legislator of natural law. While the original and most traditional theories of natural law do rely on a theological foundation, it is characteristic of modern and contemporary versions that they do not, and therefore theism has not been listed as a basic proposition.

Ancient Sources

It is generally held that the first complete formulation of a natural law theory was a product of Stoic philosophers. It is also generally held, however, that classical Greek philosophers made significant conceptual contributions to what became natural law. Plato suggests the first, moral realist, tenet of traditional natural law theory in proposing his division of the Forms and appearances. In taking such a strong realist position, Plato provides material for the claim that goodness, or at least good order, is fundamentally real and our knowledge of it can be directly produced through reason. In dialogues such as Gorgias, Protagoras, and Phaedrus, Socrates defends a notion of objective truth and knowledge over the relativistic claims of sophists, which fits the natural law emphasis on moral realism. In the Republic, he analogizes the virtuous person to a healthy body and state, which fits the second proposition that morality is self-rewarding, tends toward happiness, and is the proper state of being. In the Laws, Plato touches upon the fourth proposition by referring to a law of nature forbidding homosexual sex as unnatural, appealing to animal behavior as evidence (836c–e).

Aristotle has an even stronger claim on influencing natural law, though his contribution is contested. One writer considers natural law his "principal legacy to Christian thought" (Hastings 2000, p. 465), whereas another believes that he "figures as a natural law thinker only ambiguously and not very helpfully" (Haakonssen 1992, p. 890). Howard P. Kainz (2004) points out that the passages in Aristotle commonly used to indicate support of natural law—"Universal law is the law of nature. For there really is, as every one to some extent divines, a natural justice and injustice that is binding on all men, even on those who have no association or covenant with each other" (pp. 6–8)—come from the Rhetoric (1373b5–1373b15), and are embedded in a section giving advice to lawyers on how to argue cases. Aristotle suggests using the rhetoric of natural law when "the written law tells against our case" but suggests that when "the written law supports our case" it is better to argue that "trying to be cleverer than the law is just what is forbidden by those codes of law that are accounted best" (Rhetoric, 1375a25–1375b25). But though Aristotle may not be as clearly a natural lawyer as some have thought, he does bequeath three important ideas that get taken up by natural law later on. First, in the Physics, Aristotle speaks at length concerning teleology—the notion that all natural objects have an end they are internally driven to fulfill (their telos) and that to understand a thing we must understand the end toward which it aims (194b15–199b30). Second, in the Nicomachean Ethics, Aristotle applies this principle to discover the end of human beings, arguing that humans, as natural, aim at some specific highest good for humans, which he defines as happiness—virtuous, rational, satisfactory activity (1097a15–1098a15). The teleology of natural objects and a complex virtuous happiness as the end of human beings will figure prominently in later natural law formulations, particularly those of Aquinas. Third, in the Politics, Aristotle argues that living in a political organization is entirely natural for humans. In fact, nature implants in us a social instinct and we can tell by the fact that humans are not individually self-sufficient that the purpose of the state is to produce well-being (1253a25–1253a35). States that work for this common well-being are genuine; states that do not are "perversions" (1279a25–1279b10).

It is commonly considered, however, that the first full-fledged description of natural law arises in Stoic philosophy. In general, Stoic philosophers were drawn to the idea that the universe is controlled by a perfectly rational and fateful principle called the logos, a concept prominent in Heraclitus's thought. The logos, as a rational principle that is creative, pervades all nature, and is reflected in human beings' ability to consciously reason and express logical relations in language, unites the metaphysical, the epistemological, and the ethical. As A. A. Long (1986) writes: "[I]t is clear that logos is something which can be heard, which serves to explain things, which is common to all" (p. 145). This unity is important for a view of reason as a law that connects nature, thought, and morality. In ethics, Zeno of Citium and other Stoics advise us to accept the logos-determined activity of the universe as right and unchangeable. It is our moral obligation to live in accordance with nature and our nature includes the instinct for self-preservation and the possession of reason (Diogenes Laertius 1925, pp. 193–197). The mostly widely cited statement of Stoic natural law, however, comes from Cicero, who wrote:

True law is right reason in agreement with nature; it is of universal application, unchanging and everlasting; it summons to duty by its commands, and averts from wrongdoing by its prohibitions. … It is a sin to try to alter this law, nor is it allowable to attempt to repeal any part of it, and it is impossible to abolish it entirely. We cannot be freed from its obligations by senate or people, and we need not look outside ourselves for an expounder or interpreter of it. And there will not be different laws at Rome and at Athens, or different laws now and in the future, but one eternal and unchangeable law will be valid for all nations and all times, and there will be one master and ruler, that is, God, over us all, for he is the author of this law, its promulgator, and its enforcing judge. Whoever is disobedient is fleeing from himself and denying his human nature, and by reason of this very fact he will suffer the worst penalties. (1928, p. 211)

In this passage, many of the traditional characteristics of natural law theory are asserted—the appeal to reason, natural ends, and universality, the lawlike features of obligation, commandment and punishment, the connection to human nature, our internal ability to determine natural law obligations through intuition, conscience, or acknowledgement of impulses, and the reliance on God as legislator. These aspects of natural law were subject to refinements and modifications at the hands of later thinkers including Roman jurists, such as Gaius, who focused on understanding natural law as the rational underpinning of positive law; Ulpian, who applied the natural law to all animals; and Gratian, who focused on natural law being spelled out as biblical commands (Kainz 2004).

Medieval Sources

With St. Thomas Aquinas (1225–1274), natural law reached a summary moment and was systematized and incorporated into the dominant Christian theological tradition of the West. Aquinas is so influential on the natural law tradition that his position is often seen as paradigmatic—a response that both limits the tradition and over-theologizes it.

Aquinas begins his discussion of the nature of law in the Summa Theologiae by defining law in general as "a rule and measure of acts, whereby man is induced to act or is restrained from acting" (Summa, Part 2, Part 1, Question 90, Answer 1), which is immediately "nothing else but a dictate of practical reason emanating from the ruler who governs a perfect community" (2.1.91.1). Proper laws always aim toward the general good and, following Aristotle, the goal of human life and thus the common good, is happiness (2.1.90.2). Aquinas then distinguishes between four types of law. Eternal law is the very idea of how things should be and has been intended in God's mind. This idea of how things should be according to God has "the nature of a law" (2.1.91.1). The natural law is essentially the way in which human beings, as rational beings, are positioned within this divinely designed order of things, directed toward fulfilling their nature in that order. Aquinas says:

Wherefore, since all things subject to Divine providence are ruled and measured by the eternal law … it is evident that all things partake somewhat of the eternal law, in so far as, namely, from its being imprinted on them, they derive their respective inclinations to their proper acts and ends. Now, among all others, the rational creature is subject to Divine providence in the most excellent way.… Wherefore it has a share of the Eternal Reason, whereby it has a natural inclination to its proper act and end: and this participation of the eternal law in the rational creature is called the natural law.… It is therefore evident that the natural law is nothing else than the rational creature's participation of the eternal law. (2.1.91.2)

Aquinas adds the categories of human law (specific determinations of practical regulations) and divine law (scriptural revelations of certain specifics). It is the relationship between natural law and eternal law that is most important here, however. As Aquinas sees it, the natural law is the way in which humans participate in the eternal law, by fulfilling our natural ends in the created order which is itself the expression of the eternal idea of God. The natural law is "imprinted" on us so that we have certain inclinations toward our ends but we also have reason, which allows us to perceive and choose to follow the imprinted inclinations in the proper way. In this sense, Aquinas frames natural law as objective, grounded in human nature, dependent ultimately on God as the creator of its content, understood through reason and through observation of our own innate tendencies and capacities.

When it comes to laying out the actual rules that the natural law prescribes, the first general principle is "good is to be done and pursued, and evil is to be avoided" which is coupled with the principle that "good has the nature of an end, and evil, the nature of a contrary, hence it is that all those things to which man has a natural inclination, are naturally apprehended by reason as being good, and … their contraries as evil" (2.1.94.2). Aquinas then develops from these two principles other precepts, including the duty of self-preservation, procreation and education of offspring, seeking knowledge of God, living in society, and avoiding offending others. It is here that Aquinas begins a popular tradition among natural law theorists of laying out a set of necessary and basic human goods.

Aquinas goes on elsewhere to develop more specific rules dictated by the natural law, for example, famously outlawing masturbation, noncoital sex, and homosexual intercourse as "contrary to the natural order of the venereal act as becoming to the human race" (2.2.154.11). It is also largely on the basis of natural law reasoning that the teaching of the Roman Catholic Church rules out contraception as ever morally permissible (Hastings 2000, Catechism of the Catholic Church 1994).

It is important to realize, however that there is no simplistic equation of the natural with the moral in Aquinas. In addressing the question of whether the natural law can be changed, he distinguishes between adding to and subtracting from the requirements of the natural law and also between primary and secondary principles of the natural law. Adding to what the natural law requires is not by itself any problem "since many things for the benefit of human life have been added over and above the natural law, both by Divine law and by human laws" (2.1.94.5). Subtracting from what the natural law requires, however, depends on what level of principle we are considering. The primary principles, such as the first precept of pursuing good and avoiding evil and the immediately derivative precepts of self-preservation, and so on, cannot be changed at all. The secondary principles, however, which are "certain detailed proximate conclusions drawn from the first principles" may be changed "in some particular cases of rare occurrence, through some special cause hindering the observance of such precepts" (2.1.94.5).

With this added layer of complexity, it is incumbent upon people to use their reason and to attend to circumstances in order to determine what is and is not permissible according to the secondary principles. For example, in the pursuit of procreation, it might seem eminently natural for men to have multiple wives, yet the tradition of the church is for monogamy. How to decide this question? Aquinas argues that marriage has a primary end of producing and raising children, but also a secondary end of a social function within a community:

Accordingly plurality of wives neither wholly destroys nor in any way hinders the first end of marriage, since one man is sufficient to get children of several wives. … But though it does not destroy the second end, it hinders it considerably for there cannot be peace in a family where several wives are joined to one husband, since one husband cannot suffice to satisfy the requisitions of several wives.… (3.suppl.65.1)

Thus according to a Thomistic reading of natural law, noncoital sex to the point of climax may never be permitted but a plurality of wives might be permitted if the material resources of the husband and culture made it workable.

Finally, for understanding the immense influence of Thomistic natural law, it is important to note that human law relies on natural law for its justification and authority. While human law may add various requirements in specifics (tax codes, civil regulations, etc.) it may not subtract from primary principles. Therefore, human laws are subject to a comparative test for their justification and authority. If they conflict with the natural law, they are not just, and not true law. Aquinas says:

Now in human affairs a thing is said to be just, from being right, according to the rule of reason. But the first rule of reason is the law of nature, as is clear from what has been stated above. … Consequently every human law has just so much of the nature of law, as it is derived from the law of nature. But if in any point it deflects from the law of nature, it is no longer a law but a perversion of law (2.1.95.2).

As with Cicero years before, this idea makes it possible to judge human laws as unjust and nonobligatory, and opens the way for the possibility of just revolutions against unjust states and human laws.

Aquinas's analysis of natural law set the stage for an ongoing debate over the nature of the relationship between morality, God's will, and God's intellect. For Aquinas, the eternal law, which was expressed in material creation, was found in God's intellect, God's perfect reason. As such, natural law was not simply an edict of God's will, as divine command theorists would argue, but rather was the automatic rational relationship between a created, purposeful order and the rational beings within that order. Presumably, if God had created a different type of purposeful world than he did, there would still automatically be a derived natural law that applied to that world as a function of reason, though its specific content would be different than the existing world. In this sense, God is bound by reason, and the natural law is the immediate rational product of created order. As Aquinas writes: "the natural law is something appointed by reason, just as a proposition is a work of reason" (Summa, Part 2, Part 1, Question 94, Answer 1).

One position, credited to Gregory of Rimini, took from this view that the natural law simply illuminated which actions and goals were intrinsically good and which were intrinsically evil. As such, the natural law "demonstrates" but is not literally a law in the sense of being legislated. As Francisco Suárez (1548–1617) encapsulates it in his influential De legibus, Gregory's position is "that the natural law is not a preceptive law … since it is not the indication of the will of some superior; but that, on the contrary, it is a law indicating what should be done, and what should be avoided, what of its own nature is intrinsically good and necessary, and what is intrinsically evil" (1944, p. 189). Another group of theologians called voluntarists, including to various degrees Bonaventure, Duns Scotus, and most prominently, William of Ockham, were defenders of the notion that the natural law was the product of God's will, not his intellect. As such, God could make the natural law, and thus morality, be anything he wished. Suárez writes: "This is the view one ascribes to William of Occam … inasmuch as he says that no act is wicked save in so far as it is forbidden by God and that there is no act incapable of becoming a good act if commanded by God" (p. 190).

Suárez himself, however, takes a middle course between the "intellectualist" and "voluntarist" positions, which he sees as being consistent with Aquinas. Suárez claims that the natural law not only demonstrates what is intrinsically good and evil but also "contains its own prohibition of evil and command of good" (p. 191). As indicating intrinsic good and evil, the natural law cannot be said to be simply willed by God. However, this does not mean that there is no divine command to follow the natural law on top of whatever rational obligation we might have to follow it. In fact, "it is revealed by the light of natural understanding, that God is offended by sins committed in contravention of the natural law, and that the judgments and the punishment of those sins pertain to Him" (p. 207). What this means is that although right reason can show us the intrinsic moral status of actions, and somehow produces some binding moral force, it is natural law's necessary connection to (but not identity with) the divine law that provides commanding obligation. Suárez writes:

The binding force of the natural law constitutes a true obligation; and that obligation is a good in its own way, existing in point of fact; therefore, this same obligation must proceed from the divine will, which decrees that men shall be bound to obey that which right reason dictates. … Therefore, although the additional obligation imposed by the natural law is derived from the divine will, in so far as it is properly a preceptive obligation, nevertheless … that will presupposes a judgment as to the evil of falsehood, for example, or similar judgments (pp. 196-197; 199).

Suárez thus describes a natural law that is both morally independent of God's Will but always joined by willed legislation to follow it.

The concerns over the actual obligations implied by natural law made their way into important political and cultural disputes, including the formal debate between the theologians Juan Ginés de Sepúlveda (1494–1573) and Bartolomé de Las Casas (1474–1566) over the treatment of Native Americans by the Spanish kings. Sepúlveda, appealing to Aristotle (who claimed slavery was justified by nature in his Politics), Aquinas, and Augustine, argued that the Native Americans were "barbaric … ignorant, unreasoning … sunk in vice … cruel, and are of such character that, as nature teaches, they are to be governed by the will of others" concluding "that the Indians are obliged by the natural law to obey those who are outstanding in virtue … This is the natural order, which the eternal and divine law commands to be observed … " (Las Casas 1992, p. 11-12). Las Casas, defender of the natives, relies partially on natural law ideals by arguing that the leaders of a community are obligated to seek the common good and waging war does not seek that end, and also that the Indians are not unreasoning but instead have rational, though still incorrect, defenses of their barbaric practices. For the most part, however, he gives consequentialist arguments as to why war should not be waged, arguing that war will produce much more harm than good.

Modern Sources

Hugo Grotius (1583–1645) is variously credited with being the "father of modern natural law," the "father of natural rights," and the "father of international law." While Grotius spends most of his writing analyzing the nature of international war and its adjudication, his appeal to natural law leads in several influential directions. First, Grotius rejects the skeptical view (typified by classical Greek opponent of natural law, Carneades [c. 214–129 BCE]) that humans and all animals are simply driven by self-interest and that therefore all laws have their source in individual expediency, which may change as conditions do. Instead, Grotius argues in his Prole-gomena to the Law of War and Peace, humans have "an impelling desire for society, that is, for the social life—not of any and every sort, but peaceful, and organized … this social trend the Stoics called 'sociableness'" (Prolegomena 6). Grotius indicates that this innate sympathy and desire for peace is central: "This maintenance of the social order, which we have roughly sketched, and which is consonant with human intelligence, is the source of law properly so called. To this sphere of law belong the abstaining from that which is another's, the restoration to another of anything of his which we may have … the obligation to fulfill promises" (Prolegomena, pp. 8-9). In addition to sociableness, humans also have the rational power to discriminate between alternative actions and can choose what will actually "follow the direction of a well-tempered judgment, being neither led astray by fear or the allurement of immediate pleasure, nor carried away by rash impulse. Whatever is clearly at variance with such judgment is understood to be contrary also to the law of nature, that is, to the nature of man" (Prolegomena, p. 10).

Second, and largely because of this innate sociality and intelligence, Grotius claims that "what we have been saying would have a degree of validity even if we should conceded that which cannot be conceded without the utmost wickedness, that there is no God, or that the affairs of men are of no concern to him." (Prolegomena, p. 10). While Grotius was not the first to conceptually detach the natural law from God, his arguments lead to a significant shift in natural law language, making it easier to talk about natural law as intrinsically part of being human rather than something that reflects a divine idea. In fact, Grotius's later clarification on the importance of God's will—"the law of nature … proceeding as it does from the essential traits implanted in man, can nevertheless be rightly attributed to God because of his having willed that such traits exist in us"—ends up showcasing more the belief that human nature immediately provides the law, whatever the ultimate source of human nature (Prolegomena, p. 11). This move will permit the disconnection of God and natural morality, while making the source of obligation to follow the law a significant problem.

Third, the shift away from specifically religious natural law is made even more rhetorically available because of Grotius's development of the concept of natural rights. In The Rights of War and Peace, he first describes the term "right" as signifying what is just or at least not unjust, but then he goes on to say that "there is another signification of the word RIGHT … which relates directly to the person. In which sense, RIGHT is a moral quality annexed to the person, justly entitling him to possess some particular privilege, or to perform some particular act" (1901, p. 19). While the idea that individuals can possess moral qualities that produce privileges and impose duties on others has many conceptual problems, the upshot is that it allows for a discourse of human rights that steers clear of theological connections.

The emphasis on the social nature of human beings becomes central at this point, informing as it does both the content and general character of natural law. Some will agree with Grotius that humans have a natural sociability; some will argue that humans are naturally individualistic self-maximizers who are sociable only for practicality's sake. But the philosophical import of this talk is that even though modern philosophers will generally agree that there is a more or less fixed human nature and will continue to use the phrase "natural law," they may mean significantly different things by it.

For example, Thomas Hobbes (1588–1679) argues that nature has provided humans with certain set traits, including rough physical and intellectual equality. Out of this equality come roughly equal hopes of attaining the objects of desire and thus competition over goods, resources, and honor. With no limitations on such competition, violence ensues and a "war of every man against every man" arises. In analyzing a way out of this situation, Hobbes discusses "rights of nature," "laws of nature," and other phrases associated with the natural law tradition. Yet, when we read what Hobbes says about the character of natural laws, something seems to have changed. Hobbes says that

a law of nature, (lex naturalis ) is a precept, or general rule, found out by reason, by which a man is forbidden to do, that, which is destructive of his life. … and consequently it is a precept, or general rule of reason, that every man ought to endeavor peace … and when he cannot obtain it … seek and use all helps and advantages of war. … From this fundamental law of nature … is derived a second law; that a man be willing, when others are so too … to lay down this right to all things. (1988, pp. 86–87)

What appears to be happening here, in spite of some of the language used, is not that humans have a natural law moral obligation to seek peace, in the way Grotius might have envisioned, but rather that reason teaches us that our self-interest cannot be satisfied unless we agree with each other to give up some of our liberties and make social contracts. This means that the "law of nature" is not an objective moral obligation, but rather a pure practical realization of what we have to do in order to achieve our goals. Although it is tricky to try to use contemporary language here, it seems as if Hobbes's natural law is more about factual psychological principles and pragmatic planning. He agrees with traditional natural law theorists that we have a human nature and self-preservation is the first trait of that nature, but he sees the implications of that fact to have more to do with the satisfaction of desire than moral obligation.

This seems even clearer when Hobbes reductively defines human rights of nature as liberties to act and then defines liberties as merely "the absence of external impediments" (p. 86) and then later says that "where no covenant hath preceded, there hath no right been transferred, and every man has right to every thing; and consequently, no action can be unjust" (p. 95). Contrasting sharply with the traditional natural law claim that theft, for example, is immoral, Hobbes argues that theft only has meaning, and only becomes wrong, after social covenants are set up describing it as so. So here we see a case where the language of natural law is used but the substance is one of self-interested prudence. It is not surprising here that Hobbes's phrase, "state of nature," describes a dangerous environment that reason must be used to change. Our natural state is one of horror; our happy and peaceful state is one of artifice produced by reason.

Samuel Pufendorf (1632–1694) takes an approach both similar and somewhat more traditional. He agrees that humans are naturally self-interested and likely to engage in warlike activity to acquire the things they want. However, humans also seem to go beyond nature in excessive pursuit of the basics nature has provided them—lusting more than is necessary for procreation, seeking clothes more for show than for necessity, desiring tasty food far beyond what we need for nutrition (1991, p. 34). In a vein similar to Hobbes, Pufendorf writes:

Man, then, is an animal with an intense concern for his own preservation … incapable of protection without the help of his fellows.… Equally, however, he is at the same time malicious, aggressive, easily provoked, and as willing as he is able to inflict harm on others. The conclusion is: in order to be safe, it is necessary for him to be sociable.… The laws of this sociality … are called natural laws. On this basis it is evident that the fundamental natural law is: every man ought to do as much as he can to cultivate and preserve sociality. (p. 35)

Here, though the term "natural law" and "ought" are used, they seem to be used prudentially, not as objective moral terms. However, Pufendorf recognizes, as did Suárez, this divide between self-preserving practicality and moral obligation and brings God back in to secure obligation. "Though these precepts have a clear utility, they get the force of law only upon the presuppositions that God exists and rules all things by His providence, and that He has enjoined the human race to observe as laws those dictates of reason which He has Himself promulgated by the force of the innate light. For otherwise though they might be observed for their utility, like the prescriptions doctors give to regulate health, they would not be laws" (p. 36). Thus, Pufendorf reverts to a modified form of divine command theory in order to fasten down the lawfulness of natural law.

John Locke (1632–1704), the most important social contract theorist after Hobbes, forms yet another subtle synthesis that ends up making natural law a moral constraint on the sorts of social contracts we can legitimately produce. As in that of Hobbes, in Locke's state of nature humans have the ability to do whatever they want but unlike Hobbes, they do not have the right to do whatever they want. Locke writes:

Yet he has not liberty to destroy himself, or so much as any creature in his possession, but where some nobler use, than its bare preservation call for it. The state of nature has a law of nature to govern it, which obliges every one: And reason, which is that law, teaches all mankind, who will but consult it, that being all equal and independent, no one ought to harm another in his life, health, liberty or possessions. For men being all the workmanship of one omnipotent and infinitely wise Maker … they are his property … made to last during his, not another's pleasure. (Locke 1960, p. 271)

So we see here that even in the state of nature there is a natural law that provides a minimum moral code, namely, not to interfere with another's body, freedom, or property, and as Locke later lays out, the natural law also provides each person the authority to enforce and punish violations of this natural law (the abuse of which leads to the need to develop an unbiased state through social contract).

What is a bit uncertain here is the role of reason and God. In one sense, Locke says that reason is the natural law, which suggests a kind of prudential characterization, but he also says that it is the fact of our being the property of God that obliges us not to harm each other, which suggest a divine origin of obligation. However, it may be that reason teaches us first the moral principle that property is sacrosanct and that this principle is what informs us that as God's property we do not have the right to harm others. Locke also says that what makes a criminal is that he chooses to live by some other rule than reason, but then states that reason "is that measure God has set to the actions of men, for their mutual security" (Locke 1960, p. 272). In his constant appeal to reason for determining the specific obligations the natural law requires of us, however, Locke seems to work with the idea that reason both teaches us the content of moral truth instrumentally (we consult it), and is the natural law itself in some way.

With these sort of modifications, revisions, and perhaps even reversals, it is not surprising that natural law as a general ethical theory began to wane and by the eighteenth and nineteenth centuries, concerns about ethical theory shifted to debates among social contract theorists, skeptics, moral sense theorists, Kantians, and utilitarians. While the early social contract theorists still used the language of natural law, other philosophers clearly challenged the language and theory explicitly.

David Hume (1711–1776) famously maintained that it is a simple logical mistake to think you can "derive" a moral obligation from a biological or psychological fact (the is/ought distinction) and argued that because of the divergent definitions of the term "natural" that "nothing can be more unphilosophical than those systems which assert, that virtue is the same with what is natural, and vice with what is unnatural" (2000, pp. 302, 305).

Immanuel Kant (1724–1804) sought moral obligation in the realm of pure reason and repudiated any connection of actual contingent human psychology with moral truth. He argued in Groundwork of the Metaphysics of Morals that

everyone must grant that a law, if it is to hold morally, that is, as a ground of an obligation, must carry with it absolute necessity; that, for example, the command 'thou shalt not lie' does not only hold for human beings, as if other rational beings did not have to heed it … ; that, therefore, the ground of obligation here must not be sought in the nature of the human being or in the circumstances of the world in which he is placed, but a priori in concepts of pure reason. (1997, pp. 2–3)

It is worth noting, however, that one of Kant's formulations of the categorical imperative is "Act as if the maxim of your action were to become by your will a universal law of nature" (p. 31). In spite of this phrasing, this is not natural law theory. What Kant is talking about is the understanding of a law of nature as a Newtonian universal regularity and is asking us to consider whether we could logically will our maxims to have such a universal character. He writes: "The universality of law in accordance with which effects take place constitutes what is properly called nature in the most general sense … that is, the existence of things insofar as it is determined in accordance with universal laws." (p. 31) and later comments that "We must be able to will that a maxim of our action become a universal law. … Some actions are so constituted that their maxim cannot even be thought without contradiction as a universal law of nature" (p. 33).

John Stuart Mill (1806–1873) criticized the entire project of trying to couple morality with nature, arguing that virtually all of our actions alter nature in some way and that an attempt to imitate nature would have us follow a guide of cruelty (1969, pp. 373–402). Of course, Mill here is arguing against the claim that we should look to nature in the large sense as a guide to behavior rather than specifically paying attention to the narrower concept of human nature (something he did pay attention to), which indicates how the concept of "nature" as a more narrow moral guide was being used by the 1800s.

Finally, John Austin (1790–1859), the founder of modern legal positivism, argued that law

may be said to be a rule laid down for the guidance of an intelligent being by an intelligent being having power over him. … in the largest meaning which it has … the term law embraces the following objects:—Laws set by God to his human creatures, and laws set by men to men. The whole or a portion of the laws set by God to men is frequently styled the law of nature, or natural law: being, in truth, the only natural law of which it is possible to speak without a metaphor. … But, rejecting the appellation law of nature as ambiguous and misleading, I name those laws or rules … the Divine law, or the law of God. (2004, p. 24)

This command theory of law undermined the position that an obligation to act followed from anything other than sheer power and thus reduced natural law to nothing more than a confusing way of referring to divine command.

Contemporary Sources

In the twentieth century there was a revival of interest in natural law, as seen in the works of Jacques Maritain, Elizabeth Anscombe, Yves Simon, Ralph McInerny, Russell Hittinger, Robert George, Peter Geach, Anthony Kenny, and Alisdair McIntyre. In large part, the new attention to natural law was spurred by the Catholic Church's teachings on social and moral issues, including Pope Paul VI's encyclical letter Humanae Vitae (1968), which drew on Aquinas's moral theories to condemn artificial birth control. Prominent among the theological and philosophical defenders of the church's natural law teaching on contraception, abortion, homosexuality, and healthcare (though not necessarily following in the Thomistic tradition) were Germain Grisez and John Finnis. Grisez published an influential commentary on Aquinas's natural law system in 1965, which inspired John Finnis's work, culminating in Natural Law and Natural Rights (1980).

The heart of that book is Finnis's list of basic human goods, including life, knowledge, play, aesthetic experience, sociability (friendship), practical reasonableness (intelligently choosing and affecting one's own life), and religion (concern with transcendence) (1980, pp. 85–90). These are not moral goods, but more basically goods-for-us. It is our fundamental and self-evident awareness of these basic goods that creates moral choices for us—what are we to do? How are we to use our practical reasonableness to decide what to do? Finnis then attempts to use a "natural law method" of ethics, while still only using modern (presumably not natural law) terminology, to show purely through logic and other self-evident truths what we ought to do (p. 103). He argues for a set of basic requirements of practical reasonableness, which include a coherent, rational plan for our lives, no arbitrary preferences among either the basic goods or among persons, detachment and commitment, choosing efficient methods to achieve good, a limited attention to preference satisfaction (excluding such things as theft and murder), seeking the common good, following conscience, and perhaps the most controversial principle, "one should not choose to do any act which of itself does nothing but damage or impede a realization or participation of any one or more of the basic forms of human good." (p. 118).

It is this latter principle that Finnis believes rules out any consequentialist reasoning. Consequentialist ethics, he argues, is irrational because goods cannot possibly be measured, and therefore the ends never justify the means where the means includes damaging a basic good. Once he rules out consequentialism, the principle that a basic good cannot be impeded is "self-evident" and the moral rule can be summarized as "Do not choose directly against a basic value" (pp. 119, 123). This formulation of natural law begins with empirical claims about what things it is in our nature to value and then logically tries to come to our obligations. However, with no legislator to provide the traditional source of obligation (such as Suárez's and Pufendorf's God) there remains the question of whether this theory is actually a natural law theory. Finnis himself tells us that, like scientific laws, which are actually only metaphorically laws, "'Natural law'—the set of principles of practical reasonableness in ordering human life and human community—is only analogically law" (p. 280).

Finnis seems to think that reason by itself provides obligation, but it is not clear how this is supposed to occur. Reason can help us discover what desired ends we find in our psychological constitutions and can help us determine instrumentally how to achieve those ends, but how does reason create an obligation to pursue any end?

This question of whether their theory is properly called natural law theory also follows the most prominent twentieth century legal theorists. Lon Fuller (1964) describes a set of eight requirements that civil law must meet in order to be considered genuine law—requirements such as generality, noncontradictoriness, and nonretroactivity. In this, he is appealing to a set of objective conditions that one may subject civil laws to as a test for true lawfulness, but he emphasizes that this test is procedural rather than substantive (Bix 1996). Ronald Dworkin (1967, 1986) argues that principles of values always govern how we produce and interpret civil laws, and so there is no fundamental separation of the realms of law and morality, but this could be essentially a descriptive claim and does not imply that there is a self-evident objective moral order to which civil laws must adhere in order to provide obligations. It is perhaps primarily in the sense of providing opposition to legal positivism that these theories are classified as natural law theories.

Connections to Other Ethical Theories

While natural law is its own set of theories, the differences between it and other ethical theories are often exaggerated and oversimplified. There are significant connections and shared assumptions. For example, although Kant explicitly rejects appealing to empirical facts about human nature to determine the moral law, he begins his moral philosophy with a teleological principle widely held by natural law theorists, stating in Groundwork that "in the natural constitution of an organized being … we assume as a principle that there will be found in it no instrument for some end other than what is also most appropriate to that end and best adapted to it" (p. 8). Unlike natural lawyers, however, he concludes from this that the job of reason cannot be to produce happiness, because instinct would best accomplish that. Instead, reason's purpose is to produce a good will. Kant does connect nature and law through teleology though by claiming in Idea for a Universal History from a Cosmopolitan Point of View that "If we gave up this fundamental principle, we no longer have a lawful but an aimless course of nature" (1963, p. 13), and concluding that "The greatest problem for the human race, to the solution of which Nature drives man, Is the achievement of a universal civic society which administers law among men" (p. 16). In view of these commitments, it might be said that Kant shares with the Stoics a view of the metaphysical and epistemological aspects of the natural law, but not the essential moral aspects.

Mill, for all his criticisms of the use of the term "natural" in moral theory (Nature), is as quick as a natural law theorist to point to empirical facts about human psychology:

The only proof capable of being given that an object is visible, is that people actually see it … the sole evidence it is possible to produce that anything is desirable, is that people do actually desire it … No reason can be given why the general happiness is desirable, except that each person, so far as he believes it to be attainable, desires his own happiness. (1998, p. 168)

He is quick also to appeal to our consciences as guides: "The internal sanction of duty … is one and the same—a feeling in our mind; a pain, more or less intense, attendant on violation of duty. … This feeling, when disinterested … is the essence of Conscience" (p. 161).

And of course, given the natural law emphasis on the pursuit of happiness, the importance of developing character traits which lend themselves to happiness and flourishing, the fundamental desire for self-preservation, the practical need to interact with others, and the ability to apprehend our obligations through internal self-observation, we see strong shared assumptions with virtue theory, social contract theory, and intuitionism.

Problems for Natural Law

As seen through its historical development, the primary arguments for natural law have been that it is warranted theologically, that nature or human nature somehow imply that we should act in certain ways, that reason itself simply shows us the self-evident truth of natural law, and that it is necessarily practical that we act in certain ways given our nature. Criticisms have been leveled against these arguments and other aspects of natural law theory.

First, concerns about religion: If natural law theory relies on the existence of God, then proof of God must be forthcoming before we can move on to moral metaphysics—a complicated task. However, this point would only obviously apply to those versions of natural law which require God for moral obligation and some versions of natural law do not make this assumption. Problems do arise, though for relating natural law to divine command theory. For example, if, as Grotius argues, innate human traits have been directly willed in to us by God, then God's will is the source of moral obligation and thus natural law may be only a thin technical layer between human obligation and divine command theory. If, as Aquinas seems to think, some sort of natural law would proceed automatically from whatever world God created, irrespective of God's will, then this sort of moral relationship seems to be at least as fundamental and necessary as God—a point about which voluntarists are concerned.

Philip Quinn (2000), for example, actually emphasizes the divine command elements of Aquinas's thought, arguing that the Summa 's exoneration of Abraham in the sacrifice of Isaac story (Summa, Part 2, Part 1, Question 100, Answer 8, Reply 3) shows that Aquinas believed "the slaying of Isaac by Abraham, which would be wrong in the absence of the divine command, will not be wrong in its presence if Abraham obeys it" (p. 62). The issue is fundamentally about whether natural moral obligations are products of pure reason, and whether this implies there is some truth or reality that does not depend entirely on God.

Second, concerns about relativism: Just as voluntarist divine command theory is often seen as a type of moral relativism because God could (in some views at least) have made anything a moral obligation, the apparent natural law assumption that morality depends on the actual contingent facts of biology and psychology seems to make morality relative to species (rather than culture or the individual, as traditional relativisms argue). This is not a practical problem for determining obligations when there is only one sapient species to consider, but for ethicists such as Kant, morality could only be said to be truly objective if it was necessary for all possible rational beings.

Third, concerns about is and ought: Hume pointed out that many attempts at moral philosophy make a near-imperceptible shift from the way things are to the way things should be—a move that logically requires connecting premises often not given (Hume 2000, p. 302). This criticism has been analyzed at great length (Hudson 1969). Natural law may be an attempt to breach the is/ought divide, but historically it often either does nothing to supply the connection, or supplies it arbitrarily, or tries to supply the connection simply by appealing to reason. It is unclear, however, how reason is supposed to produce moral obligation. It may be true, for example, that choosing a short-term pleasure over a long-term basic good interferes with comprehensive happiness, and thus may in one sense be called unreasonable or irrational. But this sense of "unreasonable" is more a matter of acknowledging empirical constraints on what will actually satisfy our desires, health, or continued existence rather than serving as any sort of logical proof of a moral obligation.

Instrumentally, reason can help us to satisfy the desires and inclinations we do in fact naturally have, but it is not clear how reason is supposed to indicate that we should try to satisfy them. There is nothing formally illogical about not satisfying desires we have or securing our own health and happiness. For versions of natural law that retain God as a moral lawmaker, this problem seems to be avoided because obligation can been seen in a positivist sense as legislated—but then this Ockamist or Austinian approach returns us to the problem of whether natural law simply reduces to divine command theory.

Fourth, concerns about the goodness of nature: There is the assumption in natural law that human nature is fundamentally good (even though flawed), which legitimates our appeal to it. This is an inheritance of Christian theology, even for those versions of natural law that argue for no dependence on God. Other explanations, less committed to design and eternal law formulations of the world's development, see aspects of human nature as more adventitious and thus less morally authoritative. Human traits are not necessarily here because they are supposed to be but because they survived. As a result, many inherent traits may be prone to producing what we think of as evil acts and ends. As Mill writes in "Nature":

With regard to this particular hypothesis, that all natural impulses, all propensities sufficiently universal and sufficiently spontaneous to be capable of passing for instincts, must exist for good ends … this is of course true of the majority of them, for the species could not have continued to exist unless most of its inclinations had been directed to things needful or useful for its preservation. But unless the instincts can be reduced to a very small number indeed, it must be allowed that we have also bad instincts which it should be the aim of education not simply to regulate, but to extirpate. … among them one which they call destructiveness: an instinct to destroy for destruction's sake. I can conceive no good reason for preserving this. (p. 398)

Fifth, and related to the fourth, concerns about best explanation: One of the key purposes of natural law ethics, particularly in its modern versions, is to oppose the idea that there is no human nature, or that human nature is so widely divergent that no cultural or moral norms can be said to be better or worse than any other. In this sense, natural law is opposed to cultural moral relativism, behaviorist environmental determinism, and postmodern social constructivism. However, natural law is not the only theory that holds there is a human nature, that can produce a list of basic human goods, pays attention to biology and psychology, and opposes relativism. To some extent Rawlsian contractarianism does this, but in a way even more related to natural law, evolutionary ethics does as well.

Evolutionary ethics can take seriously the claim that the moral law is "written on our hearts" and that we only need our conscience to apprehend it. As Grotius defended the existence of the natural law by pointing to widespread regularities in moral beliefs (1957, pp. 25–26), evolutionary theorists defend the existence of an evolved moral sense, which explains cross-cultural similarity in moral emotions such as guilt and shame, and cross-culturally widespread moral restrictions on murder, betrayal, and sexual infidelity. But there is a difference.

Just as evolutionary theory covered much of the same territory as the argument from Design for the existence of God, but could explain both complexity and the existence of "imperfections" such as vestigial organs (having given up a perfect designer and therefore eliminating any expectation of perfect design), evolutionary ethics can explain both the widespread facts of human cooperation and widespread selfish violations of moral norms (having given up a perfect moral inculcator and therefore eliminating any expectation of perfect moral inculcation).

Even for nonreligious versions of the natural law, there remains the idea that our consciences and innate natures are essentially good and trustworthy and thus have some difficulty explaining why warmongering, murder, lying, addiction, and rape are both so self-evidently bad and so persistent. It seems to some then that evolutionary ethics does a better job of explaining human moral nature and human immoral nature. Of course, evolutionary ethics is at heart descriptive, arguing that moral attitudes are simply what have been successful at replication over time and not that they represent any objective moral truth (anymore than our bodies reflect imperfectly some infallible objective body). This is indeed a disadvantage if one is in search of moral prescriptions, but evolutionary ethicists can attempt moral prescription as well, having at first glance no lesser or greater obstacle to overcome in moving from facts to obligations than natural law theorists (Rachels 2000).

Contemporary Standing

Natural law theory is still active as an applied ethics (forming as it does the foundation of the Catholic Church's moral philosophy). It is also still active in some academic investigations, generating numerous titles each year in ethics and legal philosophy. It is safe to say, however, that it is a minority position in mainstream academic ethics, at least in its traditional form, and typically appeals mostly to ethicists of particular religious bents. However, the descendants (or perhaps distant cousins?) of natural law theory thrive in the form of natural rights or human rights theory, which form the backbone of much of the world's international moral discourse—particularly when criticizing a particular state's or culture's practices. Practically speaking, though, much of the rhetoric concerning natural law in its more explicit and narrow sense (in appeals to naturalness and unnaturalness) is spent on ethical issues of sexuality and reproduction, leading some critics to claim that debates over sexual morality are actually the last stand for popular traditional natural law appeals (Mohr 2005, pp. 122–123).

See also Anscombe, Gertrude Elizabeth Margaret; Aristotle; Augustine, St.; Austin, John; Bonaventure, St.; Carneades; Cicero, Marcus Tullius; Consequentialism; Duns Scotus, John; Dworkin, Ronald; Gregory of Rimini; Grotius, Hugo; Heraclitus of Ephesus; Hobbes, Thomas; Hume, David; Kant, Immanuel; Laws of Nature; Legal Positivism; Locke, John; Logos; Maritain, Jacques; Medieval Philosophy; Mill, John Stuart; Moral Realism; Peace, War, and Philosophy; Philosophy of Law, History of; Philosophy of Law, Problems of; Plato; Pufendorf, Samuel von; Rawls, John; Rights; Social Contract; Socrates; Sophists; Stoicism; Suárez, Francisco; Thomas Aquinas, St.; Thomism; William of Ockham; Zeno of Citium.

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Patrick D. Hopkins (2005)

NATURAL LAW

Natural law is perhaps the most ancient and historically persistent concept in Western ethics. Philosophers like Aristotle regarded nature as a ground of justice. Theologians like Thomas Aquinas distinguished between natural and supernatural sources of morality and law. By it Thomas Jefferson sanctioned a revolution. With it political reformers like Martin Luther King, Jr., justified civil disobedience. Upon it political philosophers like John Locke have built theories of the origin and limits of the civil state; and international lawyers, such as Hugo Grotius and Samuel Pufendorf, the order of justice between states. Despite disagreements about the theory of natural law, international bodies appeal to unwritten sources of rights to healthcare.

U.S. constitutional law has used natural law to clarify and sometimes amend the written law. Natural law undergirds the Thirteenth (1865) and Fourteenth Amendments (1868), which outlawed slavery and secured rights of U.S. citizens against state jurisdictions. Natural law also serves as a method of judicial interpretation, from which the judge looks beyond the written text of the Constitution in order to identify and vindicate rights of citizens. Today, constitutional debates have become the most public and controversial forum of natural-law discussion (Dworkin, 1985; Ely). Inasmuch as natural law is widely regarded as the moral basis for rights of privacy or personal autonomy, it is implicated in some of the most difficult biomedical issues, including abortion, reproductive technologies, and euthanasia.

The question of natural law emerges when we consider human laws and customs (Sokolowski). None is perfect, and some appear to be wicked. We then ask: What is the norm of reason in matters of morality and justice? Are moral norms merely the artifacts of human reason, devised to serve the circumstances of a particular culture? Or is there a ground that transcends cultures and histories? On what basis can laws be morally criticized and rectified?

Since these questions are fundamental to all ethical inquiry, what makes natural law different from other normative theories? There is no tidy answer. An array of moral theorists, using different theories, agree (1) that there are objective, though unwritten, moral grounds for right reason in the legislation and adjudication of human law; and(2) that moral reason must be guided by, and respect, certain values inherent in human nature (e.g., rationality and the capacity for free choice). If natural law means that moral and legal norms are grounded in reason, and that right exercise of human reason requires respect for goods inherent in human nature, then it would be exceedingly difficult not to hold a natural-law theory of one sort or another.

The healthcare professional exploring natural-law issues will face a debate often abstract and bewildering. First, what starts as a debate over particular issues in law, politics, or healthcare often becomes a debate over the concept of natural law itself. Second, what distinguishes one natural-law theory from another is not always clear; there seem to be as many different theories of natural law as there are theorists. In any case, one must remember that the rubric "natural law" often hides important disagreements among its proponents, as well as significant agreements among those who dispute its particular formulations and applications. Third, until recently natural-law thinking for the most part has not directly addressed biomedical issues. A well-developed body of natural-law literature, as found in legal, moral, and political theory, does not yet exist for biomedical issues. Thus, it will be helpful to summarize some of the main historical and philosophical themes of natural law.

Ancient Themes

Ancient Greek philosophers asked whether law and morality are due principally to nature or to convention. Aristotle, who is sometimes credited as the father of natural law, contended that "[w]hat is just in the political sense can be subdivided into what is just by nature and what is just by convention. What is by nature just has the same force everywhere and does not depend on what we regard or do not regard as just" (Nicomachean Ethics, 1134b18). While Aristotle certainly held that there are standards for judging whether a law is "in accord with nature" (Rhetoric, 1373b6), whether he had a doctrine of "natural law" is much debated (Miller). The proposition that moral judgment is rooted in the soil of nature, and not merely in human artifice, does not necessarily mean that nature is a "law."

The form of natural-law theory that came to influence Western culture arose from the confluence of Stoic, biblical, and Christian Scholastic ideas. Cicero, the ancient authority most often cited by Christians, wrote:

True law is right reason in agreement with nature; it is of universal application, unchanging and everlasting; it summons to duty by its commands, and averts from wrongdoing by its prohibitions.… It is a sin to try to alter this law, nor is it allowable to attempt to repeal any part of it, and it is impossible to abolish it entirely.… [there is] one master and ruler, that is, God, over us all, for he is author of this law, its promulgator, and its enforcing judge. (De Re Publica, 3.22.33)

Similarly, Thomas Aquinas said that "the participation in the eternal law by rational creatures is called the law of nature" (Summa theologica, 1947, I-II, q. 91, a. 2). Nature as law requires the notion that natural standards are promulgated by God. The human intelligence finds itself not merely in a natural order but under a divine commonwealth, which is a rule of law in the exemplary sense.

Aquinas and Natural Law

Since the theory of natural law as developed by Thomas Aquinas is widely regarded as the epitome of the premodern position, let us summarize his view. In the Summa theologica, Aquinas maintains that for something to be called law, it must be: (1) reasonable, in the sense of directing action; (2) ordained to the common good; (3) legislated by the proper authority; and (4) duly promulgated (I-II, q. 90). The eternal law, whereby the world is ruled by divine providence, satisfies these criteria in an exemplary way (q. 91, a. 1). Natural law, however, is principally that part of divine reason accessible to the human intelligence. It is not to be confused with the order of the physical or biological world. Law is predicated only by a kind of similitude with the order found in nonrational entities (q. 91, a. 2 ad 3).

The first principle of the natural law is that "Good is to be done and pursued and evil avoided" (q. 94, a. 2). By nature, the human agent is inclined toward certain intelligible goods. Though Aquinas never claimed to provide an exhaustive list, these goods include life, procreation and care of offspring, entering into society, and knowing the truth about God. The first precepts of natural law take the form that something is to be done and pursued with respect to these goods, or resisted if contrary to them. Why call the precepts "natural"? Because the objectives of action are grounded in human nature antecedent to our deliberation and choice. In this sense, nature signifies the (human) essence directed to its specific operation. The term natural also indicates that the first precepts stand as the basic axioms of action, and are known naturally (naturaliter) rather than learned by study or by inference. Why call the objects of these inclinations "precepts" or "law"? Aquinas maintains that human agents are capable of seeing that certain goods are worthy of pursuit; they also grasp, in an elementary way, that in choices one is morally bound to act in accord with these goods.

The first precepts, however, are not a complete moral code. Aquinas holds that human reason must develop and apply them. First precepts are developed in terms of "secondary precepts," which spell out further implications for human action. For example, from the precept that one must act in accord with the good of life and resist what is contrary to it, we reason that murder is wrong. The first precepts also require "determinations," supplied by custom and positive laws. The "determinations" are ways that the natural law is made effective in the human community. Thus, while the care and education of offspring are enjoined upon human-kind by a first precept of the natural law, how, where, and when the duty is discharged are determined by custom or positive law. Here, the virtue of prudence is paramount.

In the Thomistic scheme, the moral order in human law and politics is a kind of ecosystem, requiring for its proper function not only the universally binding precepts of natural law but also good customs, intelligently framed and emended positive laws, and acquired virtues, by which the laws are obeyed not just externally but also in the interior act of the will. It is therefore not advisable to isolate the doctrine of natural law in Aquinas from the rest of his account of moral agency. First, Aquinas flatly rejects the idea that human beings ever existed in a pure state of nature (I, q. 95,a. 1), unlike the ahistorical "state of nature" models of the modern era. Created in grace and wounded by sin, the concrete human condition, according to Aquinas, is in need of tutoring and, ultimately, of transformation by divine grace. Aquinas insists, for example, that the two great ends of the natural law—the love of God and of neighbor—obscured by sin and evil customs, require repromulgation by divine positive law (q. 100, aa. 5, 11). Second, the greater part of his Treatise on Law (I-II, qq. 90–108) puts the natural law in the double context of the divine positive law of the Old Testament (lex vetus) and the New Testament Law of Grace (lex nova). Biblical history shapes Aquinas's fully considered judgment and exposition of the natural law.

Aquinas can be absolved of the charge that he confuses moral and physical meanings of nature, as well as the charge that his account is ahistorical. Yet his theory of natural law does rely on a teleological conception of providence, and the historical cast of his thought is informed by the biblical narrative. These features are not accidental. To the extent that modern theorists reject the credibility of the teleological science of nature, and aim to provide an account of natural law that is neutral with respect to theological suppositions, the Thomist theory will be of more historical than systematic interest.

Modern Theories

In modern times, the concept of natural law has undergone considerable doctrinal and institutional development. Although the theological framework of natural law was maintained as part of public rhetoric well into the nineteenth century, it was no longer the main interest of natural lawyers. As Lloyd Weinreb notes: "The puzzles with which Aquinas and others grappled when they tried to understand the place of humankind in nature appear in [modern] guise as part of the effort to describe the relationship of the individual to the state" (p. 67). This shift of perspective and emphasis, from cosmological and theological themes to the more narrow political and legal issues of natural law, is complicated. Leo Strauss has argued that the ancient and modern theories are so radically different that they ought not to be confounded. Whether there is continuity or discontinuity between premodern and modern versions of natural law remains a disputed subject in the scholarly literature. While we cannot discuss this in detail, we can cite at least two problems that have shaped the modern approach.

NATURAL LAW AND MODERN SCIENCE. By the seventeenth century, the phrase "natural law" was expropriated by the modern sciences to denote purely descriptive or predictive aspects of natural bodies. In optics, astronomy, and physics, the relation between nature and law no longer expressed the human participation in divine providence but, rather, the intelligible, measurable, and predictable regularities in physical nature (Ruby). Teleological understanding was abandoned in favor of mechanistic explanations that relied exclusively upon material and efficient causes. The success and prestige of the physical sciences made it difficult thenceforth to interrelate the moral and physical meanings of natural law without falling into equivocation. How, for example, can law be predicated on nature without conflating physical and moral necessities? In the physical sciences, law denotes the measurable and predictable properties of things that have no freedom. But in the practical or moral sphere, law denotes principles that govern human freedom. These two meanings of natural law—nature as amenable to description and prediction, and nature as a prescriptive norm of freedom—present an ongoing theoretical difficulty in modern thought about the subject.

NATURAL LAW AND THE PUBLIC ORDER OF RIGHTS. The humane focus of natural law concerns legal and political problems of the relationship between the individual and the state. In the seventeenth and eighteenth centuries, human nature rather than authority allegedly vested in churches or kings came to represent the legitimate origin of the state and its rule of law. Philosophers and jurists wrested natural law from the controversial settings of religion and custom, and attempted to reduce it to self-evident laws of reason sufficient to ground a public order of law and rights. While the well-known dictum by Hugo Grotius that the natural law would have validity even if God did not exist captures something of the modern temper, even more pertinent is his assertion that "[j]ust as mathematicians treat their figures as abstracted from bodies, so in treating law I have withdrawn my mind from every particular fact" (Grotius, Prolegomena nos. 11, 58). Modern natural-law theorists emphasize apodictic, nongainsayable propositions, and filter out anything dependent upon the mediation of culture and religion. These theories are expected to cut through religious and political controversy in order to secure that minimum of rational consensus needed for public purposes (Gewirth). In contrast with the ancients and medievals, the minimalistic bent of modern theories is not designed to mesh with the virtue of prudence.

Natural Social Necessities

Given the new scientific meanings of nature and law, as well as the practical need to devise principles of justice sufficient to limit the modern state, two approaches to natural law dominate the modern period. One tradition keys natural law to what is needed for survival and societal peace. By nature, human beings are vulnerable, and need a certain minimal protection of their interests. Thomas Hobbes set the pattern of this tradition. Other examples of this approach are David Hume's "circumstances of justice," Oliver Wendell Holmes's "can't helps," and H. L. A. Hart's "minimum natural law." Natural law sets a background for customs and laws prohibiting violations of life, limb, and property. The advantages of this approach are at least threefold. First, the desire to protect one's life and property, insofar as it can be described and predicted, comports with the physicalist model of nature and law favored by the modern sciences. Second, it picks out elementary goods and bads that are apt to win consensus. These basic needs do not seem to depend upon the idiosyncrasies of particular individuals and their private life plans. Third, at least in the Anglo-American world, issues of life, limb, and property are easily recognized and adjudicated within a system of positive law.

However, natural necessities provide little or no reason to recognize absolute moral norms or rights that might resist the utilitarian calculations of a political majority acting for its alleged interests in peace and security. As Oliver Wendell Holmes said in his famous essay on natural law: "The most fundamental of the supposed preexisting rights—the right to life—is sacrificed without a scruple not only in war, but whenever the interest of society, that is, of the predominant power in the community, is thought to demand it" (p. 314). It is one thing to say that any system of positive law must work against the background of natural human necessities; it is quite another to hold that these pervasive natural facts about the human condition carry any prescriptive or moral force.

Natural Right of Autonomy

Another tradition, typified by Kant's dictum that one "[m]ust act as if the maxim of your action were to become through your will a universal law of nature" (Kant, no. 421,p. 30), emphasizes the autonomy of moral agents. This natural law can be expressed in the categorical imperative that humanity in one's person and in the person of others must be respected as an end in itself. As developed by many modern theorists, autonomy is a concept variously described as "moral independence" (Dworkin, 1985, p. 353), "the free choice of goals and relations as an essential ingredient of individual well-being" (Raz, p. 369), and "personal sovereignty" (Reiman, p. 43). Is autonomy a fact about human nature, or is it a moral ideal? There is disagreement about this (Schneewind). Reiman, for example, maintains that "Personal sovereignty [indicates] a natural fact about human beings, consideration of which will lead us to the natural ground of equality between human beings" (p. 43). Put thus, autonomy embraces both a natural fact and a moral principle.

Some version of the autonomist theory is the preferred approach in much of contemporary natural-law theory, for the autonomist position emphasizes specifically moral principles of law rather than mere natural necessities. It seeks to tell us not what agents typically want or need, but how and why human beings must be respected. Moreover, it comports with the humanistic premise that human beings have a native dignity based upon a rational capacity to determine their conduct. It is the rational capacity that sets (at least some) human beings apart from other entities of nature, and constitutes the axioms of the moral world.

Despite its wide appeal, three problems routinely crop up in connection with the autonomist position. First, it is not always clear whether we are enjoined to respect the capacity for autonomy or the rightful exercise of that capacity. If we are enjoined to respect the capacity itself, are we thereby duty bound to respect the agent when he or she uses the capacity in a wicked way? In short, do agents have a moral right to do moral wrong? Second, the rights and obligations that flow from this "natural" fact of autonomy are difficult to formulate except in very general terms. What can a right to autonomy mean, except that persons ought not to be treated as mere objects; and what can this mean, except that a person ought to be treated according to sound moral considerations (Raz)? Hence, while autonomists emphasize a natural right to be treated equally, it is a humanist premise rather than the conclusion of moral reasoning (Raz). Third, we can ask whether the natural capacity for self-determination is adequate for moral reasoning about the status of other nonhuman species, prehuman entities (genetic material), incipient human life (embryos), and human beings whose autonomy is diminished.

Catholic Natural-Law Theory

The Roman Catholic Church is the only international institution to hold a natural-law doctrine in both the premodern and modern phases of the theory. Conciliar decrees, papal encyclicals, and canon law both reaffirm the natural law and have applied it across a range of moral issues (Fuchs; Finnis, 1980b). The encyclical Veritatis splendor(1993) gives considerable attention to natural law. Drawn chiefly from the work of Augustine and Aquinas, the papal formulation of natural law in Veritatis is traditional, emphasizing the status of natural law as real law, promulgated by God. Although there is only passing reference to biomedical issues, the encyclical represents perhaps the clearest exposition of the theoretical underpinnings of natural law by a modern pope. The concept of natural law has also recently been applied to natural rights. The new Code of Canon Law(1983) asserts the right of the church to address secular affairs insofar as such affairs pertain to "fundamental rights of the human person" (canon 747/2).

Over the past three decades natural-law debate has focused upon the encyclical Humanae vitae (1968), which condemned contraception as a violation of the natural law, not because it is artificial but because it is contrary to nature. The encyclical's premise is that marriage (apart from considerations of sacramental theology) naturally contains both a procreative and a unitive good. The moral question is whether these goods can be deliberately separated in the particular conjugal act. The natural-law reasoning of Humanae vitae has been interpreted in quite different, and sometimes contradictory, ways by moral theologians. A 1991 study finds that at least six natural-law positions have emerged in the debate (Smith). This is because the encyclical is terse, and does not spell out its argument in the fashion of an academic exercise. But it is also due to the fact that the encyclical outlines an argument at three levels, each of which is open to debate: (1) that the conjugal act must preserve the intrinsic order toward the procreative end; (2) that the unitive and procreative goods of marriage must not be separated; (3) that the integrity of marriage cannot be maintained in its totality unless it is maintained in each and every conjugal act. Hence, its analysis of nature concerns not only the natural order of the sexual function but also the natural goods of marriage as well as the nature of the human sexual act itself. Whatever might be said about the document, it does not present a simple natural-law argument.

Critics like Charles Curran have charged that Humanae vitae confuses the physical and moral structures of human acts. Curran also charges the encyclical with adopting a "classicist worldview and methodology" that comports with neither the methods of the sciences nor the relativizing of nature by the history of salvation. Bernard Häring raises objections similar to Curran's. Not only in matters of reproduction, but also more generally in biomedical issues, Häring notes that the physician no longer defines himself as a servant of "ordered potentialities and powers of nature." Rather, he "increasingly considers himself an architect and sculptor of the given stuff of nature" (Häring). So, too, the moral theologian, he argues, must emphasize the divine mandate to creatively mold and intervene in nature. As so often happens in debates about natural law, the practical issue at hand (in this case, contraception) quickly opens onto the more abstract philosophical and theological questions about the meaning of nature and how it relates to norms of conduct.

In 1987, Joseph Cardinal Ratzinger, prefect of the Congregation for the Doctrine of the Faith, issued Instruction on Respect for Human Life (Donum vitae). The Instruction addressed a number of biomedical issues, including experimentation upon human embryos; methods of prenatal diagnosis; and in vitro fertilization, both homologous (the meeting in vitro of the gametes of married spouses) and heterologous (the use of gametes coming from at least one donor other than the spouses). Whereas Humanae vitae contended that the procreative good cannot deliberately be suppressed in favor of the unitive good, Cardinal Ratzinger argued that the natural law also prohibits separating procreation from the unity and love of the spousal act. While the argument is similar to Humanae vitae, Cardinal Ratzinger makes it clearer that natural law is a moral law, not to be confused with a "set of norms on the biological level." By nature, the conjugal act is a "personal" act of love between spouses. This guarantees that the transmission of life is an act of procreativity rather than mere reproduction. The Instruction, therefore, maintains that in vitro fertilization, whether homologous or heterologous, is contrary to the personal and unitive meaning of the marital act.

With respect to human rights, Cardinal Ratzinger argues that in vitro fertilization violates not only the natural structure of the marital act but also the "inalienable rights" of the child. The child cannot be treated as an object serving the interests of the parents but, rather, must be treated as an end in itself. Parents have only the right to perform those acts that are per se ordered to procreation. Were parents to have a right to reproduce, by whatever means, then the child would be an object to which one has a right of ownership. At least on matters of bioethics, the Instruction represents an important development in the linkage between a traditional natural-law conception of the marital act with distinctively modern arguments concerning natural rights.

Natural-law theory is in a period of transition among Catholic scholars. Some scholars working in the Thomistic tradition now emphasize the role of the virtues rather than the juridical themes of natural law (Bourke; MacIntyre). Others, notably John Finnis (1980a) and Germain Grisez(1983), have developed a theory of the relationship between practical reason and "basic human goods" (e.g., life, knowledge, play, aesthetic experience, sociability, practical reasonableness, and religion). The aim of the theory is to identify moral norms governing how basic goods ought to be chosen. It was first undertaken by Germain Grisez (1964; 1983); John Finnis (1980a) has systematically applied Grisez's work to the whole field of jurisprudence. The natural-law component of the theory is much criticized. Some argue that it has no clear connection to the Thomistic doctrine of natural theology (Hittinger, 1987); others, particularly proportionalists, argue that absolute moral norms are not easily generated by such generalized forms of human wellbeing (McCormick). Although there is considerable agreement among Catholic philosophers and theologians that natural law is important, there is less agreement about how to deal systematically with the subject.

Natural Law in Law and Bioethics

Constitutional and legal issues have occupied recent secular debates over natural law. It is noteworthy that the philosophical ground of the debate between natural lawyers and legal positivists continues to be revisited (see essays in George, 1992). At a more concrete level, however, discussion has focused upon civil liberties, particularly the right of privacy. Since this area of the law is the bellwether for many important biomedical questions, we will briefly outline the state of this discussion.

In Griswold v. Connecticut (1965), the Supreme Court invalidated a Connecticut statute forbidding the sale to and use of contraceptives by married people. The Court held that a zone of privacy protects marriage from intrusive governmental actions. Since the Constitution and its amendments do not mention the right of privacy, the Court was widely regarded as using natural law in constitutional interpretation. Indeed, the use of natural law was more controversial than the result in this particular case. In Eisenstadt v. Baird (1972), which invalidated a Massachusetts statute prohibiting the sale of contraceptives to unmarried people, Justice William Brennan reasoned that the right of privacy generally covers the decision of individuals, married or single, to make decisions about whether to "bear or beget" children. In Roe v. Wade (1973), the right to privacy was extended to abortion. Since then, it has been cited by lower courts as precedent for paternal refusal to allow the implantation of embryos. Other biomedical issues have also surfaced in the courts in terms of natural rights: "There is a fundamental natural right expressed in our Constitution as the 'right to liberty,' which permits an individual to refuse or direct the withholding or withdrawal of artificial death-prolonging procedures …" (Cruzan v. Harmon, 760 S.W.2nd 408, 434 [Mo. banc 1988] [Higgins, J., dissenting]).

It is unfortunate that some of the thorniest biomedical questions have been formulated legally in terms of a right to privacy. The moral substance of the right is often moved to the periphery in favor of the controverted issue of natural law as a tool of constitutional interpretation. Setting aside the legal questions, we can ask what are the ground and scope of a right to privacy. It is widely held that the moral basis of the right rests upon the natural autonomy of individuals to make decisions about their bodies, with respect not only to sexual conduct but also to many life-and-death concerns. The notion of the body as property has a long philosophical pedigree in the Anglo-American world(e.g., John Locke); the notion that there exists a field of private or self-regarding actions is traceable to a number of different moral theorists (e.g., John Stuart Mill). Moral and legal theorists generally have attempted to unite these themes under a right of autonomy or moral independence (surveyed in Hittinger, 1990). In Planned Parenthood v. Casey (1992), the U.S. Supreme Court reaffirmed its holding in Roe v. Wade. It is significant, however, that the Court discussed the right in the language of autonomy, and brought this language under the legal rubric of "liberty" (in section one of the Fourteenth Amendment), rather than "privacy." Because privacy has such disputable grounds in the positive law, this move from privacy to liberty in Casey can be read as an effort to find more secure grounds in the positive law for the moral right to autonomy.

Two problems attend the formulation of a right to autonomy. First, it is not clear that a natural right to autonomy can be applied with analytic precision. Even if we narrow the scope of autonomous actions to those that relate to use of the body, it would seem that contraception, abortion, and euthanasia are very different kinds of acts— not only materially but also morally. Hence, it can be objected that although autonomy is a necessary element in our consideration of these issues, it is not a sufficient condition for how they ought to be settled. Second, in Western history, the great tradition of natural rights has concerned the limitation of the coercive power of the state. In legislation and in public policy, a natural rights argument can be expected to shed light upon the principles that ought to govern the ends and the means of public force. But the right of autonomy provides only the most inchoate ground for distinguishing between legitimate and wrongful actions on the part of the state. Why, for example, should the state be prevented from intruding upon decisions about reproduction but not those concerning suicide or euthanasia? All these acts concern the body, and are plausible instances of the individual's interest in his or her autonomy. If the difference consists in the moral specifications of the acts (if, for example, abortion is adjudged morally licit or at least indifferent, while suicide and assisted euthanasia are deemed morally wicked), then autonomy needs to be augmented with other principles in order to draw a line between what belongs to the individual and what belongs to the state. If, on the other hand, one has a natural moral right to act autonomously regardless of the moral specifications of the acts, then one would seem to have a natural right to do wrong. While a government might have other reasons to tolerate wicked acts, it is unclear how a government can be bound to respect a right to do a moral wrong.

Since bioethics encompasses matters of physiological well-being, moral choice, and justice, some version of natural law might seem indispensable to how we should frame and resolve the issues. Despite theoretical problems and disagreements, nature stubbornly remains a standard for health (Kass). Until nature is exorcised, it will continue to invite natural law reflection on norms of medical practice. Modern technology urgently bids us to investigate the moral relevance of the contrast between nature and art. Furthermore, it would be hard to imagine a future in which citizens stop making claims about rights in the area of healthcare and the allocation of its resources. Natural law has become part of our repertoire of moral discourse about rights. Yet, as one critic of natural law has stated the problem: "Either the allegedly universal ends [of natural law] are too few and abstract to give content to the idea of the good, or they are too numerous and concrete to be truly universal. One has to choose between triviality and implausibility" (Ely, p. 51). The same can be said of any of the standard normative theories of ethics, whether deontological or utilitarian. With respect to any abstract theory, especially one as prodigious as natural law, one must look carefully at its different versions, and also take the applications of the theories on a case-by-case basis.

russell hittinger (1995)

bibliography revised

SEE ALSO: Abortion, Religious Traditions: Roman Catholic Perspectives; Christianity, Bioethics in; Embryo and Fetus: Religious Perspectives; Enhancement Uses of Medical Technology; Ethics: Normative Ethical Theories; Ethics: Religion and Morality; Eugenics and Religious Law: Christianity; Fertility Control: Social and Ethical Issues; Law and Morality; Reproductive Technologies: Ethical Issues; Transhumanism and Posthumanism; Virtue and Character

BIBLIOGRAPHY

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Dworkin, Ronald A. 1985. "A Matter of Principle." Cambridge, MA: Harvard University Press.

Ely, John H. 1980. Democracy and Distrust: A Theory of Judicial Review. Cambridge, MA: Harvard University Press.

Finnis, John. 1980a. Natural Law and Natural Rights. Oxford: Clarendon Press.

Finnis, John. 1980b. "The Natural Law, Objective Morality, and Vatican II." In Principles of Catholic Moral Life, ed. William E. May and William E. Baum. Chicago: Franciscan Herald Press.

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NATURAL LAW

NATURAL LAW. Natural law is a contribution to the perennial discussion of the nature of justice and morality; it is an attempt to root them in something beyond human convention and creation. The notion has had various meanings and contents—no less than the word nature itself—most of which can be traced back to Saint Thomas Aquinas (1225–1274), Roman Stoicism, and ultimately, Aristotle (384–322 b.c.e.). Constant to all its meanings is that natural law is coherent, suprahuman, objective moral order that contains the standards of what is good and just; and that it contains the standards by which human or positive law is to be judged from the perspective of a harmonious and coherent universe and is inherent in the "nature" of the world. It was born of attempts by ancient philosophers and jurists to discover—or determine—what was common to all legal systems in order to eliminate what would today be seen as the problems of "relativism" and cultural and legal "diversity." The presumption that there is a common core to all systems of morality and law that provides the standards by which they are to be evaluated leads to the issues of discovery, validation, and enforcement.

UNIVERSALITY AND PERMANENCE

Natural law, like justice, aims at universality and permanence. Operationally, like all law, it is duty-contradict, a series of moral prohibitions, permissions, and requirements. It proclaimed the union of morality and politics and emerged from an ancient worldview that saw a singular harmony in nature, manifested in the universal jus (or ius ) gentium (international law). That universality was subsequently incorporated by Christianity into its conception of the divine ordering of all creation. Aquinas separated this classical understanding into the eternal, the divine, the natural, and the human (or positive) laws. The natural was still common to all humanity and was part of God's will and was the direct source for human law. In keeping with its Stoic roots, the natural law as conceived by Aquinas was discoverable through the use of natural reason, with the difference that for Aquinas that reason had been planted in everyone by God. Justice was an irresistible, rational necessity of naturally sociable human beings.

In this Aristotelian-Thomist form, for the most part, natural law continued into the early modern period. Even Jean Bodin (1530–1596), famed for his conception of political sovereignty as the absolute power to make and enforce law, held in his Six livres de la République (1576; Six books of the commonwealth) that the state in general was under the moral aegis of the overarching law of nature and limited sovereign absolutism to the positive law.

Protestant and secular natural-law theorists retained the understanding of humans as naturally sociable and rational and viewed the natural law as that which superintended human laws. The Vindiciae, contra Tyrannos (1579; Defense of liberty against tyrants; written by Philippe de Mornay, known as Duplessis-Mornay [1549–1623], but published anonymously) pointed to violations of the natural law as one of the signs of tyranny, and the sixteenth-century Anglican theologian Richard Hooker (1553 or 1554–1600) espoused a conception of natural law that was heavily indebted to Scholasticism in his Laws of Ecclesiastical Polity (1593, et seq.).

REASON AND NATURAL SOCIABILITY

The seventeenth century witnessed the beginnings of a series of remarkable changes in natural-law theory, starting with the Dutch thinker Hugo Grotius (1583–1645), whomadereasonandnaturalsociability, rather than divinity, central to the conception developed in his De Iure Belli ac Pacis (1625; On the law of war and peace). So strong was his reliance upon these two that he suggested that the natural law would obtain even without God. Grotius was certainly not an atheist, but that charge was hurled at Thomas Hobbes (1588–1679), the English philosopher whose understanding of natural law shared many features with that of Grotius.

Sociability, Grotius argued, drove humanity into society from its prepolitical, state-of-nature beginnings; people were capable of understanding the ruling law of nature through their natural reason. Aquinas and the early-seventeenth-century Jesuit natural-law philosopher Francisco Suárez (1548–1617) had seen rationality as a reflection of divinity that enabled humans to understand God's will. Grotius appeared to have minimized that relationship, treating reason as a semiautonomous—albeit divinely implanted—and extremely important aspect of human nature. In his hands and those of his successors, this radically secularized and rationalized natural law was potentially removed from the realm of experience in which it had previously been rooted. The inherent human capacity to reason and the use of "right reason" independent of actual experience could lead to universal moral, social, and political principles by which human life was to be governed.

Perhaps the most important and influential proponent of this Grotian view of natural law was Samuel von Pufendorf (1632–1694), the first holder of a chair in natural law in a German university. In his De Jure Naturae et Gentium (1672; On natural and civil law), Pufendorf went even further and separated the natural, sociable world of human affairs and the natural law that governed it from the spiritual realm of theology. In this form, the new, secular natural law was adopted by many seventeenth- and eighteenth-century philosophers, especially Richard Cumberland (1631–1718), bishop of Peterborough (whose De Legibus Naturae [On natural laws] was published the same year as Pufendorf's work) and Jean Barbeyrac (1674–1744), the translator of Grotius and Pufendorf into French and historian of moral philosophy.

Cumberland had reached his conclusions independently of Pufendorf and was acknowledged in later editions of De Jure Naturae. Paradoxically, perhaps, Cumberland had developed some of his argument in opposition to the writings of Thomas Hobbes, who had denied natural sociability and ignored, if he did not actually deny, divinity. But Hobbes was subsequently to be ranked by Barbeyrac in the company of Grotius and Pufendorf as one of the great innovators in natural law theory.

STATE OF NATURE

Hobbes's theory, most notably in Leviathan (1651) and earlier in his De Cive (1642; On citizenship), began with an utterly undeveloped, fiercely competitive, and dangerously uncertain state of nature in which the natural law gave everyone the right to all things within their reach. People escaped this state of nature by voluntarily establishing a conventional absolutism in accord with the natural law requirement of self-preservation. Where traditional natural-law doctrine had provided a natural and rational basis for rights and liberties that persisted in some form in political society and had imposed varying limits on political authority, in Hobbes's hands, the inevitable destructiveness of natural freedom led only to a rationally established absolutism in which subjects had only as much freedom as their rulers permitted. It was the conceptual genius of Hobbes to subvert the appeal to natural law by many of his contemporaries—especially the Levellers—to attack the rule of Charles I as antithetical to their natural rights.

This Hobbesian reworking of natural law created great difficulties for his successors—he was frequently attacked and his books were subsequently banned in England—especially John Locke (1632–1704), who sought to establish a notion of secular natural law as leading to limited government. Locke is better known for his doctrine of natural rights than for his theory of natural law. The state of nature described in his Two Treatises of Government (1690) was sociable and far more peaceful than that of Hobbes, precisely because it was governed by the God-given natural law that people recognized and generally obeyed. The establishment of political—or "civil," as Locke often called it—society, accomplished by consent, was fully in accord with the law of nature and enabled people to achieve their natural ends by overcoming the uncertainties and insecurities of the state of nature. Locke's political state was to be limited by the natural justice contained in the natural law, and prolonged violations of that justice legitimated—in some cases, even required—a resort to revolution.

THE PROBLEM OF DIVINE WILL

There is a paradox inherent in a natural law theory that depends on divine will. Grotius and those who followed him recognized this problem. If God is the author or legislator of the law of nature, and its validity is a consequence of his will, then things are right or wrong because God has so directed, which makes him into something of an arbitrary but benevolent ruler. If, on the other hand, there are principles according to which God has decreed the natural law, as Aquinas seemed to have implied, then God is not omnipotent. Consigning all this to the realm of divine mystery severely limits its applicability to human affairs. The role of reason is crucial, but reason that is God-dependent simply pushes the problem one step further away. Aquinas, following Aristotle, argued for the relationship between divine natural law, reason, and human experience. But an independent reason of the sort advocated by Pufendorf requires some standard of validation. Locke tacitly sidestepped the issue in his Two Treatises, but at an earlier period in his life, in a series of lecturers he delivered in 1664 but refused to publish (published from the manuscripts in 1954 as Essays on the Law of Nature ), he had agonized over the source of natural law and how and whether it could be known.

This series of questions was faced by Pufendorf, who concluded that the will of God in matters of natural law could be determined by consulting what is humanity's long-term and therefore best interests, thereby opening the door to a rational natural law that could be professed without any direct reliance upon divine will and revolution, which was ultimately a major break from the Scholastic tradition. He further urged that the author of this break was Grotius. The focus of natural law for Pufendorf—and Grotius—shifted from the morally requisite duties of individuals to the preservation of society, a view that was passed on to the eighteenth century by Barbeyrac. He published French translations of Grotius and Pufendorf that were translated into English and enjoyed wide popularity in both languages. His Historical and Critical Account of the Science of Morality (English translation, 1729), which prefaced his edition of Pufendorf, accepted and furthered Pufendorf's understanding of Grotius as the author of the radical break in natural-law theory. Barbeyrac argued for a new school of natural-law theory that included Grotius, John Selden (1584–1654), Pufendorf, Hobbes, Cumberland, and Locke, and his view became the accepted history of modern moral philosophy.

HUMAN WILL

These moves would make human will the determiner of natural-law precepts, leaving altogether open the issue of how to resolve conflicting accounts. Ultimately, this would be dealt with by the reintroduction of experience as that upon which reason operated. And, in keeping with the precepts of natural sociability, a standard of social utility extended over time would become the measure of justice as secular natural law gave place to utilitarianism. The Scholastic doctrine of natural law remained alive in Roman Catholic philosophy and theology.

Yet another and not unrelated direction for the development of natural law thinking was already present in Locke's conception of natural rights, for his emphasis was upon the natural entitlements as limits on the behavior of others and on the actions of government. The popularity of this doctrine represents the triumph of what has been called "individualism." This part of the natural law story ends with Thomas Jefferson's (1743–1826) invocation in the Declaration of Independence of the "law of Nature and Nature's God," a cosmetic reversion to the earlier theistic conception, from which he quickly moved to the self-evident, God-given "unalienable Rights" of "Life, Liberty, and the pursuit of Happiness" as the only legitimate ends of government. Expanded into the universal "human rights" of contemporary international politics, the modernized version of natural rights has become one of the primary alternatives to utilitarianism and social good as the test for good and just government.

See also Bodin, Jean ; English Civil War Radicalism ; Enlightenment ; Free Will ; Grotius, Hugo ; Hobbes, Thomas ; Locke, John ; Rights, Natural .

BIBLIOGRAPHY

Burns, J. H., ed. The Cambridge History of Political Thought, 1450–1700. Cambridge, U.K., and New York, 1991.

Gierke, Otto Friedrich von. Natural Law and the Theory of Society, 1500 to 1800, by Otto Gierke, with a lecture on The Ideas of Natural Law and Humanity, by Ernst Troeltsch. Translated and with an introduction by Ernest Barker. Cambridge, U.K., 1958.

Haakonssen, Knud. Natural Law and Moral Philosophy: From Grotius to the Scottish Enlightenment. Cambridge, U.K., and New York, 1996.

Johnson, Harold J., ed. The Medieval Tradition of Natural Law. Kalamazoo, Mich., 1987.

Krieger, Leonard. The Politics of Discretion: Pufendorf and the Acceptance of Natural Law. Chicago, 1965.

Gordon Schochet

NATURAL LAW.

Natural law theories have a venerable place in the history of philosophy, stretching back to the time of Plato (428–348 or 347 b.c.e.) and Aristotle (384–322 b.c.e.) when the relationship between law and nature first became a central dynamic of discussion in ethics. Since then such theories have provided staple ingredients within each major phase in Western philosophy down to the time of Immanuel Kant (1724–1804) and beyond into the contemporary era. While such accounts have often been short on detailed and practical guidance on right action, the outlook of natural jurisprudence has been highly influential in ensuring a continuous focus on the alleged rationality of the natural world and the constant and uniform accessibility to the human mind of such principles of observed regularity. However, there has always been a tension between the claim that these principles are eternal and unchanging, and the particular forms and uses assigned to natural law: in Ancient Greece the focus was more on the apparently unchanging character of nature and the distressing mutability of actual law; in the medieval age St. Thomas Aquinas (c. 1224–1274) above all emphasized the accessibility of regular patterns in nature to human nature; and in the early modern era natural law theories evolved as responses first to skepticism about the sources of knowledge, and secondly in reaction to the political turbulence that followed the Reformation, which seemed to shatter the easy symmetry between the uniformity of church and state both across Europe as a whole and also within its constituent political units. In each case the position of natural law was ambiguous, both very much of its time, and yet claiming its authenticity and authority from its position outside history.

Natural jurisprudential approaches to ethics have proved difficult to integrate into the historiography of philosophy because of just this same ambiguous relationship to history itself. On the one hand, natural law was viewed as a set of eternal verities presented by God to humanity in finished and perfect shape, and found embodied in the moral and civil order as evidence of its divine fashioning, albeit in a form diminished by the Fall of Man. But on the other hand, natural jurisprudence is a product of the interaction not just of different and succeeding schools of moral philosophy, but also of the interaction of the range of plausible accounts of divine instigation and human response within wider politics and society. So, for example, the neo-Thomist and Lutheran-Aristotelian systems of natural law that evolved in the sixteenth and seventeenth centuries in Spain and Germany were both a reaction to the new ideological circumstances of the Reformation and Counter-Reformation eras as much as they were internal modifications and realignments within academic institutions of the legacy, above all, of Aquinas and Aristotle. The same epistemological ambiguity runs through the natural law systems of the early Enlightenment era and the interpretation that they laid upon the works of Hugo Grotius (1583–1645) and Thomas Hobbes (1588–1679), which were their foundation and self-conscious inspiration. The writings of Samuel Pufendorf (1632–1694), Gottfried Wilhelm von Leibniz (1646–1716), Christian Wolff (1679–1754), and Christian Thomasius (1655–1728) sought both to anchor themselves in a newly revealed metaphysics that stood outside time, and also to comment powerfully upon and if necessary direct the course of the world of contemporary practical politics.

Natural Law in the Ancient and Medieval World

At the heart of natural law is an attempt to extract general principles out of the confusing multiplicity of legal and social convention; in the Greek world, this was represented by the contrast and tension between those areas of human life governed by contingency and those controlled by the ineluctable force of nature. Given the variability of positive law both across cultures and within them, the question arose of how legal certainty could be identified and located; and immediately battle-lines were drawn between those who held that such a moral law could be found—usually as a divine creation—and those who remained skeptical of such normative claims, and either denied that there was any essential morality, or located it elsewhere. This pattern, which originated with the Sophists, was to be repeated throughout the history of natural law arguments.

Part of the explanation of why Aristotle's writings are regarded as the first important contribution to this discourse is that they adeptly try to reconcile the distinction between nature and convention. He achieves this by elevating human reason as humankind's dominant and defining characteristic, whose proper exercise mediates between what is permanent and what is ephemeral. This is taken up with greater vigor by the Stoics, and by Marcus Tullius Cicero (106–43 b.c.e.) in particular. He regarded human reason as the apex of a rational world order: human nature rather than an innate law outside human beings now provided the ground and basis for distinguishing between positive law and natural law. Moreover, all humans possessed the rational means, when properly exercised, to identify this law unaided by God, whose divine spark reason essentially is. The Stoics also initiated what was to become one of the most influential strands of natural law thinking—namely, the view that one of the core principles of natural law is a sense of broad sociability towards one's fellow humans, tempered though not obliterated by one's own personal priorities.

The rationalism of natural law still runs as a clear thread through the massive Summa Theologiae of Aquinas, despite its elaborate metaphysical architecture. Human nature and the rational conclusions that can be generated from it continue to be his point of departure. However, Aquinas is concerned to reinstate divine eternal law within his framework, and that does lead to some tension within his overall concept of natural law as a bridge between positive and divine law. He tries to overcome this by recourse to a categorical division of natural law into primary and secondary principles, thus making natural law both fixed and mutable simultaneously. This sophisticated synthesis of pre-existing views within a Christian framework proved highly influential, and was continually refined, most notably by the later Spanish Jesuit Francisco Suarez (1548–1617); but ultimately the pressures generated by the Reformation and Thirty Years' War on the one hand and Renaissance skepticism on the other required a reconfiguring of the relationship between divine and natural law, a renewed emphasis on the Stoic formulas, and a fresh initiative to link the core principles of natural law to the emergent law of nations.

Early Modern Germany

In the era that followed the conclusion of the Thirty Years' War in 1648, it was generally held that the combined effects of Renaissance skepticism and the fragmenting effect of endemic confessional strife had destroyed the coherence of preexisting accounts of political sovereignty. The rights and duties of monarchy, most especially in respect to churches and the enforcement of doctrinal and liturgical uniformity, were left open to question and redefinition as Europe sought to come to terms with the permanence of confessional division and the necessity of its diplomatic recognition. How could sovereignty remain unified and cohesive when religious truth had become fissiparous? How could absolutism be redefined in a way that preserved unity of political decision-making while paying due pragmatic recognition to the complexities of the new European order?

Nowhere were these tensions more visible than in the Holy Roman Empire, the epicenter of the recent military conflict, and the most graphic illustration in its uneasy religious tessellation of the need to find a new legitimization for political sovereignty. It is therefore no accident that it was from this region that there emerged the most systematic attempts to re-unify politics with metaphysics and devise new explanations of the appropriate exercise of political and ecclesiological power by the ruler. The pathbreakers in this respect were Grotius and Hobbes, far more than René Descartes (1596–1650), whose relative silence on morals gave no clear assistance in this area. Grotius was admired and praised above all for showing first in a series of specific works on the legal implications and meaning of colonial acquisition, and second in his larger work of synthesis, On the Law of War and Peace (1625), that there were still general principles of natural law that could be discerned right across the spectrum of international customary law. These were accessible to all, and, crucially, would obtain even if God and God's revealed intentions for humankind were taken out of consideration. From Hobbes European readers drew the key arguments of what is generally known now as voluntarism: that laws of general validity arose from the imposition of a unified, sovereign, rational will rather than the progressive discovery of general principles benignly imprinted on humanity's consciousness in the form of innate ideas. It was in the combination of Grotius's arguments in favor of the possibility and content of universal natural law, and Hobbes's insight into how those laws may be isolated and implemented in contemporary, fragmented practical politics that produced a truly modern theory of natural law, associated with Pufendorf and Thomasius. It evoked in turn a powerful hostile reaction in the work of Leibniz and Wolff, which tried to rework the views of Aquinas in a different idiom.

The contest (for that is what it effectively became) between the voluntarism of Pufendorf and the essentialism of Leibniz was mainly played out within a framework of university disputation, but also spilled over importantly into the public arena in debates over such issues as confessional reunion. At stake here in essence was the way in which the principles of moral knowledge were obtained, an apparently recondite area of learning, but nevertheless one with crucial implications for method in all areas of modern philosophy. In his major work On the Law of Nature and Nations (1672), Pufendorf argued that humans gain knowledge of morals in a way that parallels the manner in which they devise languages, that is, through the imposition of categories and meanings to create shared, mutually accessible structures. God may give humans revealed truths, but this forms but one part of human duties; the majority of these duties are devised through unaided reason, which God gave to humans to use in this free fashion. From this initial insight, explicitly grounded in Stoic thought, emerges a complex analytical structure that frames an elaborately contractarian politics weighted heavily through the prudential calculations of individuals in an absolutist direction. It also resulted in a clearly articulated Erastian church politics, vesting the civil power with final control and powers of resolution in religious disputes.

In contrast to this, Leibniz and Wolff regarded the work of Pufendorf and his followers as an attempt to provide practical resolutions of disputes from poorly argued philosophical premises that either guilefully or ineptly justified secular voluntarism. In its place, Leibnizian posited an elaborately conceived metaphysical approach that sought to explain natural law in terms of divine justice and the "charity of the wise," arguing in essence that all practical morality can be derived from the reservoir of truth located in the perfect wisdom of God. Less daring in the practical politics with which it eventuated, Leibnizian natural law nevertheless performed virtuosic surgery on the corpse of Protestant-Aristotelian natural law, ensuring that Wolff's textbooks enjoyed equal credibility and popularity in both Protestant and Catholic universities until the later eighteenth century. Leibniz also pointed out disquietingly secular overtones in the work of the followers of Pufendorf that inhibited their unequivocal acceptance of their work even within Protestant Germany.

Early Modern France

While the grandest systems of natural law emerged in Germany, there was also a sustained focus on ethical discourse of this type among the French Huguenots, exiled by Louis XIV (1638–1715) after the Revocation of the Edict of Nantes in 1685, and forced therefore to construct a new political identity for themselves within a cosmopolitan intellectual framework, rather than that of a state. Their most eloquent writers, such as Jean Barbeyrac (1674–1744) and Jean-Jacques Burlamaqui (1694–1748), sought to defend a right to religious conscience while retaining a political order that was primarily absolutist in character. The particular circumstances of their ideological preferences therefore led them to develop a proto-liberal language of rights in association with religious toleration that was genuinely original and powerfully influential, not least on John Locke (1632–1704). But the Huguenots also had to confront more directly than any other group of writers the potentially illiberal and austerely utilitarian (using that term loosely) aspects of Pufendorfian absolutism, whose voluntarist assumptions sometimes appeared to produce results rather similar to the divine-right absolutism pursued for wholly different reasons by Louis XIV. This was a paradox not lost on Jean-Jacques Rousseau (1712–1778), who, with intimate knowledge of the local Swiss context of these writers, later castigated the Huguenots, and the natural law school as a whole, as a very clear case study in subservience to absolutism and a failure to follow through an analysis of the rights of conscience with sufficient rigor.

In four particular respects, the natural law disputes of the period between 1625 and 1760 left an important philosophical legacy. Firstly, the issues of how far religious toleration was to be permitted, what its political consequences should be, and what were the sources of its intellectual justification were played out within and refracted through the discourse of natural law above all others. Natural law theories therefore provided the framework for the discussion of the major question of the day on the interface between political theory and practical politics. Secondly, although this was not fully intended, the crucial separation of the fields of ethics and moral theology, argued for by Grotius, Pufendorf, and their followers, ultimately resulted in the final downgrading and devaluing of the formal divine content and origin of ethics and the promotion of individuals as separate self-sufficient moral persons capable of undertaking rational voluntary transactions. Thirdly, this Pufendorfian argument produced several very important discussions of the nature of contractarian government, of the right to own property and to pursue economic interactions untrammeled by the state, that powerfully anticipated some of the most radical and influential ideas of the philosophes and of the Scottish Enlightenment. Finally, the natural lawyers' preoccupation with securing links between the law of nature and the law of nations established the view that reason of state arguments were not sufficient in the world of public affairs, thus—ironically—reinstating a link between "eternal" principles of human ethics and the law of nations, just when the link between divine and natural law had been irretrievably severed.

Natural Law and Natural Rights

The disappearance of natural law arguments from mainstream philosophy was not nearly so abrupt in the nineteenth century as is often made out, as can be seen from the curricula and textbooks adopted at many universities. Nevertheless, the combined influence of Kantian idealism and utilitarianism did serve ultimately to undercut several of the key claims of the theorists of the preceding two centuries. In his Foundations of the Metaphysics of Morals (1785), Kant essentially generated a fresh account of moral obligation that was located not in the principles of human nature, but in an autonomous will freely exercising practical reason: Obligation lay not in the harmony of a principle with human nature, but in whether a law could be objectively generalized in relevantly comparable circumstances. Thus it appeared that natural law arguments only yielded empirical "counsels of prudence" about human behavior, not conceptually coherent moral yardsticks. A second blow was struck by Jeremy Bentham (1748–1832), who stressed that there was no "external consideration" that permitted natural jurisprudence to distinguish between one person's judgment of the law of nature and another's: natural law had to act as its own circular proof and guarantor, which was unacceptable. Attempts to distill a common set of principles from the infinite variety of the law of nations were bound to fail; he believed it to be far better to move outside the categories of reason and human nature altogether, accept the pluralist nature of human definitions of the good life, and reassert the supremacy of legal positivism, based on accommodating majority preferences. This point was particularly difficult for natural lawyers to answer, given that they had failed to observe how easily their view that knowledge of the law of nature was not reliant on God could slide into a statement that grounds for obeying natural law are not dependent on God either—a conclusion that left no clear criterion of obligation to fall back upon.

However, the eclipse of natural law arguments was by no means complete even at the beginning of the twenty-first century. While natural rights theories have pursued their own separate trajectory towards an assertion of the protection of individual rights as a good in itself, perhaps best embodied in the American philosopher Robert Nozick's Anarchy, State and Utopia, a number of Catholic theorists, most notably the Australian author John Finnis in Natural Law and Natural Rights, have reworked the idea of shared goods inherent in human nature, though the content of that list of shared goods and the relationship between them has proved to be controversial. As with the earlier versions of natural law theory that have taken their stand on human nature and its attributes, this version too stands or falls on the richness or poverty of its conception of that human nature, and on the clarity and self-awareness with which human nature is neutrally described or prescribed in relation to other norms at each step in the argument. All such theories explore very difficult philosophical territory because they seek to unify two essentially different projects: to provide specific prudential advice on how best to achieve one's objectives (implying a recognition that human nature and its needs change in line with historical circumstances in ways that reason alone does not always fully comprehend), together with a parallel recognition that for human insights to be generalized as valid law, they need to be assessed according to a sole and unvarying standard, usually identified as rational truth. Those thinkers who have best overcome these paradoxes, such as the Stoics, Grotius, and Pufendorf, lived in periods of significant social dislocation, but were stimulated to identify and narrow general principles attributable to reason that were also imaginatively rich enough to meet the shifting empirical shoals of their own political and existential crises. That is why they are still worth studying in the twenty-first century, for this juxtaposition of moral philosophy with moral exigencies is a task that is never completed, despite the shift in intellectual frameworks that makes the natural law era seem so distant and different from that of the present.

See also Christianity ; Human Rights ; Scholasticism ; Toleration .

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