cannot alter that law which we call the natural law comes merely from the fact that His will cannot do away with His most perfect essence, that God cannot be at variance with Himself and cannot, as the Apostle says, deny Himself” (Kleutgen). This is the fundamental reason for rejecting moral and legal positivism. The will is not the law; on the contrary, it can only be right law when it is guided even in God by reason and intellect. “But to say that justice depends upon mere will is to say that the divine will does not proceed according to the order of wisdom, which is blasphemy.”13
Good is to be done, evil is to be avoided: this basic norm of the natural moral law has thus the character of an axiom. The real question, however, is that of its application to the concrete case. As another expression for the first rule of the lex naturalis, as general principles known to all, St. Thomas mentions love of God and of one’s neighbor. Man knows other principles only through deductive reason, yet not with altogether unerring certitude. For, in contrast with the speculative reason, the knowledge of the practical reason is more severely menaced in its clarity by the passions, by sinful inclinations. These conclusions from principles are for St. Thomas, as he explains in a searching inquiry into the problem, identical with the Decalogue, or Ten Commandments. The Decalogue contains the most essential conclusions for the simple reason that its precepts do not result from an arbitrary arrangement made by God, but from the fundamental distinction of good and evil. The first table of the Decalogue (first three Commandments) embraces the moral norms that relate to the worship of God; these required a special promulgation, in the view of St. Thomas, because they are not so evident as the laws found in the second table. The latter (the last seven Commandments), which are derived from the mutual relations among men and from the essence and goal of human nature, are, on the other hand, known more readily and with greater evidence. Human society in all its groupings ought to be built up in accordance with justice.
The Decalogue (second table) presents the norms that follow from the essential relationships which in their turn are given in the essential nature of man as a rational, free, and social being. These precepts, as norms with a material content, protect the family and parental authority (Fourth Commandment), human life (Fifth Commandment), the person in the capital sense of husband and wife (Sixth Commandment), property (Seventh Commandment), and honor (Eighth Commandment); lastly they forbid (Ninth and Tenth Commandments) inordinate, illicit longing for those goods which are especially exposed to covetousness and, moreover, whose wrongful appropriation does not arouse that natural abhorrence which infractions of the Fourth, Fifth, and Eighth Commandments do.14 St. Thomas regards it as self-evident that the further deductions from these conclusions do not possess the same evidence, since they necessarily lose, in favor of particular prescriptions, the universal character required for evidence. Furthermore, they are not so unmistakably recognizable that errors about them may not arise in the minds of individuals as well as among groups.15 Moreover, they do not share in the prerogative of immutability enjoyed by the principia communissima as well as by the conclusions which make up the contents of the Decalogue.
For instance, from the nature of the legal institution, from the agreement with reason and from the right of property, which in the general sense is protected by the Seventh Commandment, it follows that goods held in trust should be restored to their owner. Nevertheless, as St. Thomas points out, such goods may be withheld from their owner in case they are to be used for treasonable purposes.16 Here the further conclusion does not hold good, although the universal norm of acting according to reason, the suum cuique, continues absolutely to govern the case. Some “matters cannot be the subject of judgment without much consideration of the various circumstances. Not all are able to do this carefully, but only those who are wise.”17 “In the very application of the universal principle to some particular case a mistake can occur through an inadequate or false deduction, or by reason of some false assumption”;18 and in the matter of its secondary precepts, “the natural law can be blotted out from the human heart, either by evil persuasions … or by vicious customs and corrupt habits.”19 Therein, moreover, practical reason differs significantly from theoretical reason, which is less subject to such disturbing influences.
This does not, then, mean merely that there is in St. Thomas no trace whatever of the extravagances of the rationalistic natural law current in the seventeenth and eighteenth centuries, since according to him only the Decalogue belongs to the contents of the natural law. It further means that the lex naturalis or ius naturale does not render positive laws superfluous, but actually calls for them. St. Thomas gives scarcely any attention to the doctrine of a state of nature, because he has no need of the latter for establishing the natural law. Now, the farther removed the conclusions are from the principia communissima, the more numerous and varied become the possible decisions. Hence a positive law must determine, must decide with greater exactness for concrete cases, what the correct application and conclusion are. There is all the more need of such determination because human nature, deprived and hence wounded somehow (though not destroyed or depraved) by original sin,20 must be—and in conformity with its inner goal also ought to be—constrained to good and restrained from evil. Self-education or addiction to goodness does not pertain to man as such. Consequently men stand in need of a clearly prescribed and adequately sanctioned system of norms, which emanate from an authority and power that in their inmost reality serve justice, and in the individual serve to perfect the essential nature of man. They are therefore ethical. St. Thomas is no romantic optimist like Rousseau.
Furthermore, it is precisely the object of the positive law to render the citizen virtuous. It is not merely a question of maintaining order, or external peace; the law should rather act as a medium of popular education to transform those who live under common legal institutions into perfect citizens. For this very reason positive norms, determinate coercive measures, and a more exact definition of the circumstances in which the general principle shall be applied, are imperative. Thus the definition of what theft consists in is given with the lawfulness of private property. But the punishment which should follow theft, if arbitrariness is to be avoided, requires, with respect to the procedural verification of the theft as well as to the sentence and its execution, exact legal provisions which vary with times, cultures, and individual peoples.
Here, in connection with the positive law which is therefore always “something pertaining to reason,” St. Thomas arrives at the nature of law. It has to do essentially with community life. On the other hand, it is distinguished from and contrasted with social ethics through its being directed to external order. The law wills that man conduct himself in such and such a manner; it concerns the external forum (vis directiva). It is the norm to be enforced: compulsion (vis coactiva) is proper to law, not to morality.
From this inner connection of every positive law with the lex naturalis St. Thomas rightly concludes that the positive law may not conflict with the natural law. So far as it is in conflict with the latter, i.e., with the unchangeable norms, it is not law at all and cannot bind in conscience. For the force and significance of the law consist precisely in the obligation in conscience. Yet it may at times be right to obey even an unjust positive law (one that is not against the natural law: e.g., a law that imposes an unjust tax burden), because the higher natural-law norm enjoins in individual cases the sacrifice of a particular good to a more general good. For instance, the general goods of security under law and the external order of peace constitute a higher value than does the individual right to just treatment in the levying of taxes. It is consequently not the unjust law that binds, but the higher norm of peace and of maintenance of the community.
In this fashion, then, all law, down to and inclusive of its positive individualization, is connected by means of the natural moral law with the eternal law and lives on the latter. Thus rectitudo practica, reasonableness or the relation to human nature still is, and ought to be, the essential element even in the positive law. For St. Thomas the law is somehow reason, not mere arbitrary will.21 The natural law remains the measure of the positive law. But this position is intimately connected with the doctrine of the immutability of the natural law and the enduring essential nature of man, as well as with the primacy of the intellect over the will in both God and man.
But can God, by His absolute power, dispense from the precepts of the Decalogue? St. Thomas unqualifiedly answers that the Ten Commandments admit of no dispensation whatever. “Precepts admit of dispensation