The history of the natural-law idea exhibits a uniform doctrinal development from the first Scholastics down to the able leaders of the scholastic revival of recent times. Its two culminating points were the synthesis of St. Thomas Aquinas and, following the heaviest assault made inside Scholasticism by the Occamists on the idea of natural law, the work of Vittoria, Bellarmine, Suarez, Vasquez, and De Soto (to mention only the most distinguished of the Late Scholastics). And the period after World War I again produced more understanding and esteem for a uniform doctrinal development that has been substantially independent of fashionable philosophies and of a jurisprudence with special sociological or political ties.
Scholasticism has dealt exhaustively with the problem of natural law. Not one of its exponents has failed to treat of the natural law, either in general in connection with the discussion of the virtues or in particular under such headings as De legibus or De iure et iustitia. And with the lex naturalis they handled, though not always with the aid of special distinctions, the ius naturale and ius gentium in the sense of the traditional formulas of Roman law. This holds true from Alexander of Hales to Thomas Aquinas, and thence down to the great masters of Late Scholasticism. It further holds good for the theologians and philosophers of the philosophia perennis, whether they were contemporaries of Pufendorf and Thomasius or of Savigny, down to the increasingly esteemed representatives of the scholastic revival which set in at the close of the nineteenth century.
In following the doctrinal development it is worthy of note that the antithesis of lex-ratio and lex-voluntas, applying here in the setting of theological speculation and in general to the lex naturalis inclusive of the natural law in the stricter sense, coincided structurally with the doctrines of the respective thinkers concerning God. But it is also noteworthy that later, when the natural-law doctrine had been severed from its theological moorings and hence secularized, the same thought patterns repeated themselves. Now, however, they were detached from the medieval form of Summa and applied solely to law in the narrower sense. The result has been that natural law is the consequence of the doctrines of the priority of the intellect over the will (law is reason) in both God and man, of the knowability of the essences of things and their essential order, their metaphysical being and the ordered hierarchy of values. Positivism, on the other hand, is the consequence of the doctrine of the primacy of the will with respect to the intellect in both theology and human psychology. Besides, voluntas here means more than mere will: it denotes passion, irrational appetite, and so on. Positivism signifies the renouncing of all efforts to know the essences of things (nominalism), the repudiation of the metaphysics of hierarchized being and value. Accordingly it is also found in the same conceptual pattern in the thinking of the nineteenth and twentieth centuries, even though it is concealed under different names.
Relativism in ethics, legal positivism, the theory of will in public and international law, nominalism and agnosticism in epistemology and metaphysics form down to the present a united front with the mysticism of a biological positivism appearing in natural-law dress. On the other side stands the conviction of unalterable principles of morality and law, of the idea of right as object of a philosophy of right, of the natural law, of the possibility of knowing the nature of things, of objective values and an ultimate unity of being and oughtness as well as the possibility of a true theodicy, or natural theology. And this antithesis continues on, in an ever more acute form, into the domain of constitutional theory and practice. The powerful position, in Anglo-Saxon countries, of the judiciary which understands and interprets (functions of the intellect) in contrast to the enactment of law through the will of the legislature rests ultimately upon the philosophical view that law is reason, not will. This means that right is discernible in the nature of the case or lies in the legal institution regulated by law, not in the will of the legislator: not, that is to say, in the wording of the law representing such a will or command. Such formulas as those found in the administration of justice in Anglo-Saxon countries (especially in the United States), where formal natural-law thinking has never disappeared among judges, are continually recurring even today.4
It was not with St. Anselm of Canterbury (1033–1109), often called the first of the Schoolmen, that Scholasticism began to concern itself more seriously with the natural law, but rather with the first great author of a Summa, Alexander of Hales (d. 1245). Deeper interest in it thus arose first and foremost from the philosophical preoccupation with laying a solid foundation for ethics, for law and the social forms of family and state, for a doctrine of society and the state. This interest was considerably heightened, however, in connection with the exegesis of certain passages in the Old Testament.
That is, the thesis of the immutability of the lex naturalis and ius naturale presupposes the intrinsic immorality and unlawfulness of certain actions, and it consequently excludes any dispensation from the norms of the lex naturalis. But such a position seemed to conflict with some Old Testament stories, whose moral tone and authority made it necessary to conclude that a dispensation is nevertheless possible. Such cases are, for instance, Yahweh’s command to Abraham to offer up his son Isaac in sacrifice (Gen. 22:2); the polygamy of the patriarchs; God’s instruction to the prophet Osee: “Go, take thee a wife of fornications” (Osee 1:2; cf. also ibid., 3:1); the injunction laid upon the Jews or permission accorded them at the time of the Exodus to take away with them vessels of silver and gold as well as raiment lent to them by the Egyptians (Exod. 3:21 f.; 11:2 f.; 12:35 f.); divorce openly allowed to husbands in the Mosaic legislation (Deut. 24:1–4); the reply of the angel Raphael to Tobias’ question about his identity: “I am Azarias the son of the great Ananias” (Tob. 5:18), which seems materially and formally to amount to a lie. All these cases called for a thorough discussion, from the theological and exegetical angles, of the question of the immutability, i.e., the essential nature, of the lex naturalis. But at the same time they were a warning not to be too doctrinaire in determining the content of the natural law.
Alexander of Hales, falling back upon St. Augustine’s teaching, hit upon a beautiful figure: the eternal law is the seal, and the natural moral law is its impression in the rational nature of man, which in turn is an image of God. Now, the laws of thought, as unchangeable norms of thinking, must govern speculative reason, the understanding, if the latter is to serve the purpose of its nature, the perception of truth; and such laws are immediately evident and certain. In the same way there exist for willing and acting in the domain of the practical reason supreme moral principles which are equally evident and sure. Thus every deed and action is moral only when it is performed in accordance with these principles. Moreover, this immanent natural moral law can never be destroyed. Yet the further conclusions from the supreme principles may well become obscured in individuals through the working of the passions and through a turning away from God, the Author of the natural law. To explain this possibility Alexander borrows a figure from Plato: the sun ever remains the same, yet darkness ensues when clouds pass before the sun or when, during a solar eclipse, the moon prevents the sun’s light from reaching the earth.
Although he held fast to the immutability of the first principles, Alexander of Hales at first sought to explain the changeableness of the further conclusions, observable in the Old Testament as well as elsewhere, by adopting the Stoic distinction, transmitted in the writings of the Church Fathers, of a primary natural law anterior to original sin and of a secondary one subsequent to original sin. The status naturae integrae, the theological state of nature preceding original sin, would in itself, as St. Augustine had already taught, have produced life in society, marriage, the family, and the political community. (This state of nature accordingly differs considerably from the individualistic state of nature, which indeed was directly opposed to the status civilis.) But had this state of nature been realized, community of goods, equal personal freedom, and a legal order unaccompanied by the use of force would have prevailed. Only in the state of fallen nature, after original sin, did private property, restrictions upon liberty, the coercive power of the state, and personal inequality arise. But the natural law underwent thereby no alteration; for even now the basic norm, men must live peacefully with one another, remains in force. Hence only the application of this norm has changed, not the norm itself. The secondary natural