The most momentous attempt to find an absolute and eternal standard of value is presented by the doctrine of natural law.

      The term “natural law” has been claimed by various schools of philosophy and jurisprudence. Many doctrines have appealed to nature in order to provide a justification for their postulates. Many manifestly spurious theses have been advanced under the label of natural law. It was not difficult to explode the fallacies common to most of these lines of thought. And it is no wonder that many thinkers become suspicious as soon as natural law is referred to.

      Yet it would be a serious blunder to ignore the fact that all the varieties of the doctrine contained a sound idea which could neither be compromised by connection with untenable vagaries nor discredited by any criticism. Long before the Classical economists discovered that a regularity in the sequence of phenomena prevails in the field of human action, the champions of natural law were dimly aware of this inescapable fact. From the bewildering diversity of doctrines presented under the rubric of natural law there finally emerged a set of theorems which no caviling can ever invalidate. There is first the idea that a nature-given order of things exists to which man must adjust his actions if he wants to succeed. Second: the only means available to man for the cognizance of this order is thinking and reasoning, and no existing social institution is exempt from being examined and appraised by discursive reasoning. Third: there is no standard available for appraising any mode of acting either of individuals or of groups of individuals but that of the effects produced by such action. Carried to its ultimate logical consequences, the idea of natural law led eventually to rationalism and utilitarianism.

      The march of social philosophy toward this inescapable conclusion was slowed down by many obstacles which could not be removed easily. There were numerous pitfalls on the way, and many inhibitions hampered the philosophers. To deal with the vicissitudes of the evolution of these doctrines is a task of the history of philosophy. In the context of our investigation it is enough to mention only two of these problems.

      There was the antagonism between the teachings of reason and the dogmas of the Church. Some philosophers were prepared to ascribe unconditional supremacy to the latter. Truth and certainty, they declared, are to be found only in revelation. Man’s reason can err, and man can never be sure that his speculations were not led astray by Satan. Other thinkers did not accept this solution of the antagonism. To reject reason beforehand was in their opinion preposterous. Reason too stems from God, who endowed man with it, so there can be no genuine contradiction between dogma and the correct teachings of reason. It is the task of philosophy to show that ultimately both agree. The central problem of Scholastic philosophy was to demonstrate that human reason, unaided by revelation and Holy Writ, taking recourse only to its proper methods of ratiocination, is capable of proving the apodictic truth of the revealed dogmas.³ A genuine conflict of faith and reason does not exist. Natural law and divine law do not disagree.

      However, this way of dealing with the matter does not remove the antagonism; it merely shifts it to another field. The conflict is no longer a conflict between faith and reason but between Thomist philosophy and other modes of philosophizing. We may leave aside the genuine dogmas such as Creation, Incarnation, the Trinity, as they have no direct bearing on the problems of interhuman relations. But many issues remain with regard to which most, if not all, Christian churches and denominations are not prepared to yield to secular reasoning and an evaluation from the point of view of social utility. Thus the recognition of natural law on the part of Christian theology was only conditional. It referred to a definite type of natural law, not opposed to the teachings of Christ as each of these churches and denominations interpreted them. It did not acknowledge the supremacy of reason. It was incompatible with the principles of utilitarian philosophy.

      A second factor that obstructed the evolution of natural law toward a consistent and comprehensive system of human action was the erroneous theory of the biological equality of all men. In repudiating arguments advanced in favor of legal discrimination among men and of a status society, many advocates of equality before the law overstepped the mark. To hold that “at birth human infants, regardless of their heredity, are as equal as Fords”⁴ is to deny facts so obvious that it brought the whole philosophy of natural law into disrepute. In insisting on biological equality the natural law doctrine pushed aside all the sound arguments advanced in favor of the principle of equality before the law. It thus opened the way for the spread of theories advocating all sorts of legal discrimination against individuals and groups of individuals. It supplanted the teachings of liberal social philosophy. Stirring up hatred and violence, foreign wars and domestic revolutions, it prepared mankind for the acceptance of aggressive nationalism and racism.

      The chief accomplishment of the natural law idea was its rejection of the doctrine (sometimes called legal positivism) according to which the ultimate source of statute law is to be seen in the superior military power of the legislator who is in a position to beat into submission all those defying his ordinances. Natural law taught that statutory laws can be bad laws, and it contrasted with the bad laws the good laws to which it ascribed divine or natural origin. But it was an illusion to deny that the best system of laws cannot be put into practice unless supported and enforced by military supremacy. The philosophers shut their eyes to manifest historical facts. They refused to admit that the causes they considered just made progress only because their partisans defeated the defenders of the bad causes. The Christian faith owes it success to a long series of victorious battles and campaigns, from various battles between rival Roman imperators and caesars down to the campaigns that opened the Orient to the activities of missionaries. The cause of American independence triumphed because the British forces were defeated by the insurgents and the French. It is a sad truth that Mars is for the big battalions, not for the good causes. To maintain the opposite opinion implies the belief that the outcome of an armed conflict is an ordeal by combat in which God always grants victory to the champions of the just cause. But such an assumption would annul all the essentials of the doctrine of natural law, whose basic idea was to contrast to the positive laws, promulgated and enforced by those in power, a “higher” law grounded in the innermost nature of man.

      Yet all these deficiencies and contradictions of the doctrine of natural law must not prevent us from recognizing its sound nucleus. Hidden in a heap of illusions and quite arbitrary prepossessions was the idea that every valid law of a country was open to critical examination by reason. About the standard to be applied in such an examination the older representatives of the school had only vague notions. They referred to nature and were reluctant to admit that the ultimate standard of good and bad must be found in the effects produced by a law. Utilitarianism finally completed the intellectual evolution inaugurated by the Greek Sophists.

      But neither utilitarianism nor any of the varieties of the doctrine of natural law could or did