Bahnsen on Aquinas

Hello everyone and welcome back to Deeper Waters where we are diving into the ocean of truth. I’d like to continue tonight examining the position of presuppositionalism. I have before me Greg Bahnsen’s book which I have read called “Van Til’s Apologetic.” In looking at natural theology, Bahnsen has a few criticisms of Aquinas, but upon looking at the criticisms, it seems that Bahnsen is not really familiar with the works of Aquinas. For one thing, not one of Aquinas’s writings is ever directly cited that I know of. That having been said, let’s look at those points to be examined.

On page 557, Bahnsen says that Aquinas and Joseph Butler, who I will not be talking about, both say a great deal about what man is and what reality is before discussing the existence of God or the truth of Christianity.


I simply ask anyone to go to the Summa Theologica. Here in order are the main sections.

Sacred Doctrine.

The One God.

The Blessed Trinity.


The Angels (Spirit).

The Six Days (Matter).

Man (Spirit and Matter).

In fact, the very first question raised about man directly is question 75.

Yes. Aquinas obviously spent a great deal on man before getting to God. Had the Summa simply been picked up and looked through, this statement would not have been made.

Much of the condemnation of natural theology is the belief that man can know God as He is by reason alone. At least, that is what we are often accused of saying. However, let’s see what Aquinas himself really says about the importance of sacred doctrine in the very first question of the Summa.

I answer that, It was necessary for man’s salvation that there should be a knowledge revealed by God besides philosophical science built up by human reason. Firstly, indeed, because man is directed to God, as to an end that surpasses the grasp of his reason: “The eye hath not seen, O God, besides Thee, what things Thou hast prepared for them that wait for Thee” (Isaiah 64:4). But the end must first be known by men who are to direct their thoughts and actions to the end. Hence it was necessary for the salvation of man that certain truths which exceed human reason should be made known to him by divine revelation. Even as regards those truths about God which human reason could have discovered, it was necessary that man should be taught by a divine revelation; because the truth about God such as reason could discover, would only be known by a few, and that after a long time, and with the admixture of many errors. Whereas man’s whole salvation, which is in God, depends upon the knowledge of this truth. Therefore, in order that the salvation of men might be brought about more fitly and more surely, it was necessary that they should be taught divine truths by divine revelation. It was therefore necessary that besides philosophical science built up by reason, there should be a sacred science learned through revelation.

Note that God is seen as one who surpasses the grasp of the reason of man. Aquinas says that there are truths that exceed human reason which God Himself must have revealed if they are to be known.

Second, Aquinas does say there are truths about God that can be discovered by reason unaided by special revelation, however, these would only be found by a few, because only a few would be intellectually capable, it would be after much time, because it would take a long time to work out the doctrine, and it would contain many errors, due to the difficulty of the subject.

Third, the reason these were revealed was that it was necessary for our salvation. Note that Aquinas says that if all you have is reason, you will not reach salvation. This is a far cry from the way that traditionalism is usually presented as having a low view of Scripture.

On page 629, Bahnsen tells us that if Aquinas wants to say he knows God exists, he is obligated to tell us everything about God. Why? Note that Aquinas does say there are several aspects of the nature of God that can be known. However, there are several that cannot be known.

Bahnsen tells us on the same page that if Thomas the theologian hears that God created the universe out of nothing and tells this to Thomas the philosopher, that the philosopher will say that this cannot be known.

Bahnsen is not treating Aquinas fairly here again. Let’s see what Aquinas says in Question 46 of the Prima Pars of the Summa in the second article.

On the contrary, The articles of faith cannot be proved demonstratively, because faith is of things “that appear not” (Hebrews 11:1). But that God is the Creator of the world: hence that the world began, is an article of faith; for we say, “I believe in one God,” etc. And again, Gregory says (Hom. i in Ezech.), that Moses prophesied of the past, saying, “In the beginning God created heaven and earth”: in which words the newness of the world is stated. Therefore the newness of the world is known only by revelation; and therefore it cannot be proved demonstratively.

Note here what Aquinas says. Aquinas does not say that the truth that God created the world cannot be known. He says it cannot be proven by demonstration. There is nothing wrong with such a statement. Consider what he says right after that:

I answer that, By faith alone do we hold, and by no demonstration can it be proved, that the world did not always exist, as was said above of the mystery of the Trinity (32, 1). The reason of this is that the newness of the world cannot be demonstrated on the part of the world itself. For the principle of demonstration is the essence of a thing. Now everything according to its species is abstracted from “here” and “now”; whence it is said that universals are everywhere and always. Hence it cannot be demonstrated that man, or heaven, or a stone were not always. Likewise neither can it be demonstrated on the part of the efficient cause, which acts by will. For the will of God cannot be investigated by reason, except as regards those things which God must will of necessity; and what He wills about creatures is not among these, as was said above (Question 19, Article 3). But the divine will can be manifested by revelation, on which faith rests. Hence that the world began to exist is an object of faith, but not of demonstration or science. And it is useful to consider this, lest anyone, presuming to demonstrate what is of faith, should bring forward reasons that are not cogent, so as to give occasion to unbelievers to laugh, thinking that on such grounds we believe things that are of faith.

The very first sentence is of utmost importance. He states that the knowledge that the world was created cannot be known by reason alone much like the Trinity. Philosophy cannot prove that Christianity is true. If you disagree, use nothing but reason alone and prove that God is triune and that he sent his Son to die for our sins and that the Son rose on the third day.

At the end, Aquinas also says the reason that we do know that this happened is because of revelation. Aquinas does not downplay Scripture at all. He sees it as essential to having a more than just cognitive knowledge of God. It is essential to having a salvific knowledge of God.

Now what does that mean for philosophy. Is it totally useless? Far from it. Philosophy is the handmaiden to the knowledge of God. Philosophy cannot prove the Trinity or Christianity, but once we have had those truths revealed, they can be defended by philosophy. So, Thomas AS a theologian can know that God created the world, but Thomas AS a philosopher would say, “Using reason alone, I cannot demonstrate that God created the world.” Precisely.

You would think that for those who are making a deal about man supposedly following autonomous human reason that they would want to embrace such a position. It is one that admits that man by reason alone cannot reach to a saving knowledge of God. This is not the view usually presented and when listening to them or reading them, I urge the reader to consider checking on the people that they criticize in the traditionalist camp.

Now it could be Aquinas is wrong in all that he said. However, what is important tonight is that Bahnsen is wrong in what he says about Aquinas.