I’m listening to an audiobook on Saint Thomas Aquinas, narrated by Chartlon Heston. I have never read Aquinas’ greatest work, Summa Theologica. However, I did read the wikipedia entry.
Here is a summary of Aquinas’ view of the law.
According to Question 90, Article Four of the Second Part of the Summa, law “is nothing else than an ordinance of reason for the common good, made by him who has care of the community, and promulgated.”
All law comes from the eternal law of Divine Reason that governs the universe, which is understood and participated in by rational beings (men and angels) as the natural law. The natural law, when codified and promulgated, is the human law.
In addition to the human law, dictated by reason, man also has the Divine law, which, according to Question 91, is dictated through revelation, that man may be “directed how to perform his proper acts in view of his last end,” “that man may know without any doubt what he ought to do and what he ought to avoid,” because “human law could not sufficiently curb and direct interior acts,” and since “human law cannot punish or forbid all evil deeds: since while aiming at doing away with all evils, itwould do away with many good things, and would hinder the advance of the common good, which is necessary for human intercourse.”
It should be noted that human law is not all-powerful; it cannot govern a man’s conscience, nor prohibit all vices, nor can it force all men to act according to its letter, rather than its spirit.
Furthermore, it is possible that an edict can be issued without any basis in law as defined in Question 90; in this case, men are under no compulsion to act, save as it helps the common good. This separation between law and acts of force also allows men to depose tyrants, or those who flout the natural law; while removing an agent of the law is contrary to the common good and the eternal law of God which orders the powers that be, removing a tyrant is lawful as he has ceded his claim to being a lawful authority by acting contrary to law.
The idea that law today comes from Divine Reason, or Natural Law would be naive at best. Our laws are merely favors that the political class bestows on the those (lobbyists etc) that keep them in power. Quid pro quo has replaced natural law.
Thomas was right that law can not prohibit all vices. The idea that we can legislate morality is as misguided now as it was in 1274.