Morality is governed by a law built into the nature of man and knowable by reason. Man can know, through the use of his reason, what is in accord with his nature and therefore good. Every law, however, has to have a lawgiver. Let us say up front that the natural law makes no sense without God as its author. "As a matter of fact," said Hans Kelsen, probably the foremost legal positivist of the twentieth century, "there is no natural-law doctrine of any importance which has not an essentially religious character." The natural law is a set of manufacturer's directions written into our nature so that we can discover through reason how we ought to act. The Ten Commandments, and other prescriptions of the divine law specify some applications of that natural law. Charles Rice, 50 Questions on the Natural Law (San Francisco: Ignatius Press, 1995), 28-29.