The Council refers back to the classic teaching on God’s eternal law. Saint Augustine defines this as “the reason or the will of God, who commands us to respect the natural order and forbids us to disturb it”. Saint Thomas identifies it with “the type of the divine wisdom as moving all things to their due end”. And God’s wisdom is providence, a love which cares. God himself loves and cares, in the most literal and basic sense, for all creation (cf. Wis 7:22; 8:11). But God provides for man differently from the way in which he provides for beings which are not persons. He cares for man not “from without”, through the laws of physical nature, but “from within”, through reason, which, by its natural knowledge of God’s eternal law, is consequently able to show man the right direction to take in his free actions. In this way God calls man to participate in his own providence, since he desires to guide the world – not only the world of nature but also the world of human persons – through man himself, through man’s reasonable and responsible care. The natural law enters here as the human expression of God’s eternal law. Saint Thomas writes: “Among all others, the rational creature is subject to divine providence in the most excellent way, insofar as it partakes of a share of providence, being provident both for itself and for others. Thus it has a share of the Eternal Reason, whereby it has a natural inclination to its proper act and end. This participation of the eternal law in the rational creature is called natural law”. (VS 43)

The Church has often made reference to the Thomistic doctrine of natural law, including it in her own teaching on morality. Thus my Venerable Predecessor Leo XIII emphasized the essential subordination of reason and human law to the Wisdom of God and to his law. After stating that “the natural law is written and engraved in the heart of each and every man, since it is none other than human reason itself which commands us to do good and counsels us not to sin”, Leo XIII appealed to the “higher reason” of the divine Lawgiver: “But this prescription of human reason could not have the force of law unless it were the voice and the interpreter of some higher reason to which our spirit and our freedom must be subject”. Indeed, the force of law consists in its authority to impose duties, to confer rights and to sanction certain behaviour: “Now all of this, clearly, could not exist in man if, as his own supreme legislator, he gave himself the rule of his own actions”. And he concluded: “It follows that the natural law is itself the eternal law, implanted in beings endowed with reason, and inclining them towards their right action and end; it is none other than the eternal reason of the Creator and Ruler of the universe”. (VS 44)

In the classic restatement of the five primary precepts below, Veritatis Splendor mentions the synderesis rule “do good and avoid evil” and then redefines the primary precept “worship of God” as “appreciation of beauty”.  How absolute does this make natural law? And what else does the document slip in? PB

Precisely because of this “truth” the natural law involves universality. Inasmuch as it is inscribed in the rational nature of the person, it makes itself felt to all beings endowed with reason and living in history. In order to perfect himself in his specific order, the person must do good and avoid evil, be concerned for the transmission and preservation of life, refine and develop the riches of the material world, cultivate social life, seek truth, practise good and contemplate beauty. (VS 51)

Consequently the moral life has an essential “teleological” character, since it consists in the deliberate ordering of human acts to God, the supreme good and ultimate end (telos) of man. (VS 73)