CHAPTER V., Part II. Of Those Heretics who are not guilty of the sin of Heresy. Before we speak in detail of this class of heretics we must explain what is meant by LAW and CONSCIENCE.
§ 1. NATURAL LAW. (According to St. Thomas Aquinas)
God governs and directs the material world and all irrational creatures according to the laws of his omnipotence and wisdom, having provided every creature with means proportioned to the end which it has gradually to fulfill in time and place. "Thy Providence, O Father, governeth all." (Wisd. xiv. 3.) " God, with a certain law and compass, enclosed the depth; he compassed the sea with its bounds, and set a law to the waters, that they should not pass their limits." (Prov. viii. 27-30.) As to rational creatures - angels and men - God wishes to govern them by the law of goodness and justice.
The law of God's goodness for men is that they shall always glorify God by doing his holy will; that all their homage and adoration are due to him alone, and are never to be given to any creature; that they are to honor, reverence, and love those who gave them birth and brought them up; that they are not to kill one another, nor live like brutes, nor rob one another, but that every one is to treat his fellow-men as he wishes to be treated by them. To this law of divine goodness, God added for mankind the law of his justice; that is, if any one refuses to obey this law of divine goodness, he shall be subjected to the torments which God's justice has decreed for all rebellious creatures.
This law of his goodness and justice God impressed upon mankind from the very beginning. "See," says St Paul, " the goodness and severity of God: towards them, indeed, that are fallen, the severity: but towards thee, the goodness of God, if thou abide in goodness." (Rom, xi. 22.)
This law of God's goodness and justice is also called Natural Law - Law of Nature, because it is naturally impressed on the mind and heart of every rational being, and makes him know the difference between good and evil.
As man possesses the gift of reason, or, as it is some times called, "the light of nature," no man is left in utter ignorance of God and of his will - of the Natural Law. "God has not left himself without testimony" (Acts, xiv. 16), even among the heathens, who, if they do not have full light and knowledge, may yet, as St. Paul told the Athenians, "feel after him, or find him" (Acts, xvii. 27.) "For when the Gentiles." he says, "who have not the law, do by nature those things that are of the law, these, not having the law, are a law unto themselves, who show the works of the law written in their hearts, their con science bearing witness to them." (Rom. ii. 14, 15.) This light of nature is a participation of the eternal law or wisdom of God. "The light of thy countenance, O Lord, is signed upon us," says the Royal Prophet (Ps. iv.).
Thus indicating that the light of reason, which makes us distinguish between good and evil, right and wrong, is nothing else than the impression of divine light on the soul of man.
As all men have this light of nature as a rule of right and wrong, no man can plead utter ignorance of right and wrong. Hence it is that we find, even in the heathen nations, the obligations of the natural law respected. This eternal, natural law of right and wrong is called moral law, because natural law, or sound reason, is the rule and standard of good morals; it is the rule to guide men in all their actions; it tells them what is good and bad, what they must do or avoid.
All men, without exception, know the light of nature, the first and general principles of right and wrong. But all do not know the necessary conclusions deduced from these principles. A geometrician in Paris comes to the same conclusion as another in London or in any other part of the world, that, for instance, three angles of a triangle are equal to two right angels, etc. Practical reason draws similar conclusions, if we do not lose sight of general principles; but by deviating from these principles, reason varies with circumstances. For instance, if a sum of money was entrusted to you, reason commands you to give it back to the owner. But if you knew he wanted it for the purpose of committing some bad action, as vengeance against his neighbor or country, then reason forbids you to give it to him for such a wicked deed. Still, some may think and act differently, and be, therefore, mistaken in losing sight of general principles, as others fall into error in overlooking the first principles. Natural law, therefore, is invariable for all, as long as they do not lose sight of the first principles of right and wrong.