From his Catechetical Instruction on the Apostles’ Creed, St. Thomas Aquinas writes:
Among all the truths which the faithful must believe, this is the first — that there is one God. We must see that God means the ruler and provider of all things. He, therefore, believes in God who believes that everything in this world is governed and provided for by Him. He who would believe that all things come into being by chance does not believe that there is a God. No one is so foolish as to deny that all nature, which operates with a certain definite time and order, is subject to the rule and foresight and an orderly arrangement of someone. We see how the sun, the moon, and the stars, and all natural things follow a determined course, which would be impossible if they were merely products of chance. Hence, as is spoken of in the Psalm, he is indeed foolish who does not believe in God: “The fool hath said in his heart: There is no God”(Psalm 14.1).
It is tempting to read this passage as St. Thomas’ “endorsement” of Intelligent Design. We must remember that St. Thomas was a proponent that academic disciplines should be divided because each has a methodology that is proper to them. He was also a proponent of the hierarchy of the sciences; that is to say, he believed that some academic disciplines held an elevated position by their very nature and therefore could and should use the finding of the lower subject to advance themselves. The highest of all academic subjects is theology, and a close second is philosophy. So Aquinas would say that whereas the biologist should teach only biology in his classroom, the philosopher and theologian could use the findings of biology for to clarify and make arguments for their own positions.
Now we do see that St. Thomas believes that studying the world leads one to the conclusion that God not only created the world, but also governs the world. Of course, 13-century science is rather primitive when compared to modern science, but it was more advanced than many people think. From my limited reading on the subject, it seems to me that we can say that the seeds of modern science were planted in the 13th century by two men — St. Albert the Great and his student, St. Thomas Aquinas. Both of these men believed in a relative autonomy of the world; that is, they believed that God governs the universe by placing laws in the fabric of nature, and that these laws can be studied apart for any direct appeal to God’s power.
That being said, it is interesting how St. Thomas defines a believer in God: “He . . . believes in God who believes that everything in this world is governed and provided for by Him.” This statement is a flat rejection of the notion of God as the Great Clockmaker — the one who sets things in motion but is no longer active in the universe. Even though St. Thomas believed in the relative autonomy of the world — that God indeed gave laws to the world — he still maintains that to believe in God one must also believe that God actively governs the world.
How is this possible? How can one believe that God actively governs the world while simultaneously believing that God placed laws into the fabric of nature?
The answer lies in St. Thomas’ understanding of God’s creative power. Thomas taught — and the Church herself teaches — that all things are continually held in existence by God’s creative power. To state negatively, if God were to pull back from any piece of existence, that piece would cease to exist. Therefore, everything that happens — from the rotation of the planets to the death of a deer, from a monk kneeling in prayer to a man committing adultery against his wife — is possible only because God’s creative presence holds those things in existence, thereby making their actions possible. This is the basis of St. Thomas’ teaching that to believe in God means to believe not only that God created all things, but that God also governs all things.
But we must ask another question: How does God’s creative power in all things translate into God’s governance of all things?
To answer this question fully would take a considerable amount of time. But the heart of the answer is this: God governs all things by his will. God’s will is that all men be saved. That’s what is called his perfect will. In order to achieve this end, God either directly wills something to happen or permits it to happen because he knows that more people will be saved than if it did not happen.As the authors of Radio Replies says:
We must distinguish between God’s positive will, and His permissive will. He positively wills all the good that happens. Suffering He permits to occur, and this only when he foresees that good can result from it. He positively wills that I should be holy. If He foresees that I will make use of good health to sin and to lose my soul, He may mercifully permit my health to be ruined, and thus lead me to Him where He would otherwise lose me.
So at the heart of God’s governance of the world is our salvation. This is why St. Thomas teaches that to believe in God means to believe “that everything in this world is governed and provided for by Him.” God provides for our salvation by governing the world.