The Impossible Proof

Josh Rasumssen

Josh Rasmussen is a contributor to

I had a professor who announced to the class that God's existence couldn't be proven. Her belief was stated as a matter of fact as if no one could deny it unless blinded by religious zeal. I challenged my professor: "Why do you think God's existence can't be proven?" I asked. She looked at me incredulously. "No one has proven the existence of God," she said. I responded, "How do you know that? And even if it's true that no one has proven the existence of God, I don't think anyone has proven that the existence of God cannot be proven. So why is it so ridiculous to think that God's existence is provable?" She explained to me that if God's existence could be proven, then we would all know about it, and that it's just clear that we believe in God by faith, not by "proof." As a young college freshman, this was an intriguing conversation for me with my humanities professor. Although her position seemed quite possible, it just didn't strike me as being quite as obvious as she and the rest of the students seemed to think. "How do we know that God's existence can't be proven?" I wondered.

Since then, I've had time to reflect deeply on the question of whether God's existence is provable, where by provable I mean that a rationally inescapable proof can be given to demonstrate the existence of God, such that any rational person who understands the proof, would "see" that its conclusion follows. I'm optimistic about such a proof for the following reasons:

1. I think true statements tend to be provable, and I think it is true that God exists.
2. Contemporary cosmological arguments seem to be closing in on an undeniable proof (I won't go into detail about this point here).

I'm skeptical about the denial of such a proof for these reasons:

1. Philosophical objections by Hume, Kant, and contemporary atheists do not rule out a cosmological type proof.
2. There are strong sociological reasons to explain why skeptics would resist even sound proofs for the existence of God.
3. One need not directly observe God to prove that God exists (empiricism is false).
4. Although faith is more than a belief grounded in reason, it need not be less that that.
5. I've simply never come across a convincing argument against the possibility of proving the existence of God.
6. The sciences and mathematics do not exhaust our ways of knowing what is true.

I want to focus point (6). Math and science are characterized by the analysis of sentences that are "publicly" knowable. What I mean is that the conclusions of scientific and mathematical investigations do not rely on inner feelings, emotions, or intuitions. Rather, they rely on empirical or logical facts that anyone can "see", at least in principle. Arguments that rely on subjective experiences are typically labeled, "opinions." People are free to have their own opinions, but when it comes to objective facts, well, people are expected to believe objective facts. Objectivity is the basis for all secure knowledge and rationality, while subjectivity is the locus of all fantasies and religious superstitions. Thus, proofs must be based on objective facts rather than subjective experiences.

However, the assumption that knowledge is only secure if rooted in objective facts is not only false, but it is obviously false when you think about it. Let me show you. Close your eyes and try to imagine a bouncing ball. Up, Down, Up, Down. Can you see it? It may be hard to get a crisp image of the ball like you might be able to do in a vivid dream. But at the very least you tried to imagine a bouncing ball. You did try, right? So consider the following fact about yourself:

F: I tried to imagine a bouncing ball

You may be surprised to realize that F is not an objective fact. F is not publicly accessible. It is a fact that only you can know for sure. And yet it is clear that you do know F. In fact you can use F to prove other facts. Consider the following proof that you are not a rock:

1. I tried to imagine a bouncing ball
2. Rocks cannot try to imagine things
3. Therefore, I am not a rock

This conclusion may be trivial, but it serves to illustrate that sound proofs can be based on subjectively known premises. Premise (2) may not be known with certainty, but it does seem to be the best scientific explanation for the "behavior" of rocks. If you are concerned that the small chance that (2) is false disqualifies the argument from being a strict proof, then just replace (2) with something more trivial like 2 as follows:

1. I tried to imagine a bouncing ball
2. If X is true, then X is possibly true
3. Therefore, it is possible that I tried to imagine a bouncing ball

Again, it's a trivial conclusion, but it illustrates my point that we can gain real knowledge based on arguments with subjective facts. Notice that the proof is person relative. If you didn't try to imagine the bouncing ball, then premise (1) will not be true for you. Does that mean you might turn out to be a rock after all? Not likely since there are countless other ways for you to know that you are not a rock (just look in the mirror). However, there are some facts that seem to be knowable only by a proof that relies on subjective premises. For example, consider the following proof:

1. I remember thinking about having ice cream twice today.
2. I remember thinking about having ice cream once yesterday.
3. 2>1
4. Therefore, I remember thinking about having ice cream more times today than yesterday.

There is no way to prove (4) objectively. Even if we could scientifically find a physical brain state for each kind of thought a person has, there is no way to do determine this correlation without finding out a person's inner thoughts. Thus, not only can subjective proofs give us secure knowledge, often they are our only source of knowledge on certain matters.

Now back to the question of knowing that God exists. First of all, I'm interested in a proof that is universal. A universal proof is a proof with premises that are knowable for any person. This might mean that no proofs about anything are universal since young children (say under a couple years old) may not have the psychological capacity to know that the premises in the Pythagorean theorem, for example, are true. Therefore, I only mean that a premise is "knowable" if any mentally healthy adult has the capacity to recognize the truth of the premise. If there is a proof for the existence of God that is universally knowable, then the truth of its premises will be accessible to any properly functioning adult. Might such a proof be possible?

I suspect that a successful proof for the existence of God is going to be based on premises that are subjectively knowable. The reason for this is that I can only know for sure that I am a person (a being that experiences thoughts, feelings, and decisions) by subjective introspection. One cannot even come up with empirical evidence to show that one acts like a person until one knows how persons typically act, and one cannot know how persons typically act without knowing that there are persons to begin with. So it seems to me that one has to know that persons exist in order to know how persons act, and one has to know how persons act in order to know that there exists a divine Person who has in fact acted. Thus, the arguments for the existence of God typically follow the general pattern:

1. X is true.
2. Only a "supernatural" person can make X true.
3. Therefore, a supernatural person exists.

So for example the Kalam cosmological argument:

1. X = "the universe began to exist".
2. Only a "supernatural" person can make X true.
3. Therefore, a supernatural person exists.

The fine-tuning teleological argument:

1. X = "the universe is within finely-tuned parameters that make life possible".
2. Only a "supernatural" person can make X true (or probably, X results from a supernatural person).
3. Therefore, a supernatural person exists (or probably, a supernatural person exists)

Many other arguments could be given. But are any of these arguments sound? Or if they are sound, are their premises certain. Perhaps not. But perhaps so. Consider the following argument for the existence of God:

1. I have changing thoughts, feelings, and decisions.
2. Therefore, I am a changing person.
3. Therefore, a changing person exists.
4. Whatever changes has the potential to change.
5. Whatever has the potentiality to change has the potential to cease to exist.
6. Therefore, there exists a person that has the potential to cease to exist.
7. Whatever has the potential to cease to exist cannot be eternal.
a. Whatever is eternal has no potential to come to be or to cease to be.
8. Therefore, there exists a person that is not eternal.
9. Therefore, there exists a person that has come to be.
10. Whatever comes to be has a cause of its being.
11. Therefore, there is a person that was caused to exist.
12. A cause cannot be lacking in the essential qualities of its effect.
13. Therefore, the cause of a person is itself a person.
14. There cannot be an infinite regress of persons.
15. Therefore, there is a first uncaused person.
16. Whatever is uncaused is eternal (the contra positive of 10).
17. Therefore, there exists an eternal person.
18. Whatever is finite has the potential for change.
19. Therefore, whatever is finite has the potential to cease to exist (from 5).
20. Therefore, whatever is eternal cannot be finite (7a).
21. Therefore, the eternal person cannot be finite in any of its essential attributes.
22. All persons have at least some value, some knowledge, and some power.
23. Therefore, there exists an eternal Person who infinite in knowledge, value, and power.

Is this proof sound? Well, there are a number of premises that may need explication, but I'm optimistic that sufficient explication and defense of the questionable premises can be given. At least I doubt that it can't be given. If there is a universal proof for the existence of God, I think it is going to be very much like the one above. I'm just not as confident as my professor that no universal proof for the existence of God is possible. I suspect my optimism about proving the existence of God stems from my recognition that secure knowledge is not restricted to math and science but can be built from premises describing subjective knowledge as well.

Copyright © 2003. Used by permission of