It is common to say that God’s existence can’t be proven even among those who believe in God. But is this belief really as obvious as people seem to think. What does it mean for a proposition to be provable? Can anything be absolutely proven? People do not seem to question the possibility of mathematical proofs, and so it would be strategic to examine the nature of these proofs. If a>b and b>c, then a>c. This is a principle known to be true by any rational mind, and this identity can be used to demonstrate that other identities are true. I think a practical definition of a proof is a system that shows that a proposition is true by demonstrating it is logically equivalent to a proposition that is known to be true. Let’s see how this definition might apply to matters of existence. If I experience via sight the existence of a chair and also that of a table, I can know that these experiences are different. I can use logic to prove that the number of things that I experience is greater than zero. This is simply because 2 experiences is greater than 1, which is also greater than 0. This logic follows from the identity above (i.e. a>b>c). It seems then that at least some propositions can be proven about existence. However, the practical nature of a proof ought not to be exclusively knowable to only one person (the person with the experience). How can the proof that "I" experience more than one thing be known by someone who isn’t experiencing what I’m experiencing? This I think is the troubling question which underlines the reason that people think God can’t be universally proven. For the existence of God is a question of existential matters, and such matters are experienced differently by different people. Even more troubling is the question, how can anyone even conclusively prove to himself that God exists without the ability to experience an infinite and eternal experience? For surely a finite mind can’t conceptually experience an infinite being. Are these problems insurmountable?

I’m not convinced that they are. For it may not be necessary to experience a "thing" in order to know that that thing exists. For instance, what if the content of an experience included the knowledge that that experience can’t exist without being explained by another existing thing? If the proof for God is to be universal, then this experience must be immediately accessible to any rational person. The only experience that is readily accessible to anyone is the experience of personal existence. I experience that I exist and that the way I exist is finite, temporal, and changeable. If I have any doubts about the attributes of my existence, I only need to reflect on the meaning of infinite, eternal, and changeless, and it becomes obvious that I experience none of these qualities in my being. Since every rational person can immediately know the experience of her own existence and that it is changeable, finite, and temporal, it follows that a very basic proof can be made for the existence of something changeable, finite, and temporal. We’ll call this thing being A. Now if it can’t be proven that God exists, then that means there is no way to demonstrate that reality containing being A is equivalent to reality containing being A and God. In other words if God can’t be proven, then it can’t be the case that the existence of God is knowably necessary for the existence of being A. But it doesn’t seem obvious to me that being A can exist without God. It seems possible that there might be some logical analysis that can demonstrate that God is necessary for being A.

As a result, I don’t see why rational people should accept the idea that God’s existence can’t be proven without question. For even if no proof has yet been discovered, that certainly doesn’t mean a universal proof is undiscoverable.

Even if no universal proof is possible, that doesn’t mean that a person can’t know that God exists based on unique, personal experience. But even if this knowledge is also impossible, that still doesn’t mean that God’s existence can’t be known to be probable given a universal or even a unique, personal experience. However, this essay isn’t an investigation of the reasonableness of theistic belief. For theism might be reasonable for a person to believe even if no universal proof is possible to realize by human minds. Rather, this essay is an investigation of the possibility that theism can be universally proven.

Since I’m not aware of any arguments that directly show that being A can exist independently of God, I think it might be worth exploring what a universal proof for God’s existence might look like if it existed. God is minimally defined as a being that is eternal, infinite, and changeless. This definition leads me to propose the following format for a theistic proof.

1. Something changeable exists (a posteriori)
2. Whatever is changeable must be caused by another (a priori)
3. An infinite regress of causation of changeable things is impossible (a priori)
4. Therefore, an unchangeable thing must exist to cause the first changeable thing (a priori).
5. Whatever is not changeable must also be eternal and infinite (a priori).
6. Therefore, the changeless, eternal, and infinite God exists.

Now, (1) is known immediately a posteriori, and I don’t know of any rational person who would question its validity. (2) is definitely open for debate. Some people claim to know that (2) is true, while others think its validity is merely epistemologically reasonable or even unreasonable. (3) suffers from the same controversy as (2), and (5) doesn’t seem to be known directly. If this weren’t challenging enough to the notion that God’s existence is provable, this proof in its general form seems to be the only way a universal theistic proof could possibly be developed. For nothing can be known about existence strictly a priori, and so (1) is necessary. I of course am assuming that all ontological type arguments for God’s existence which are based strictly on logic fail. I can’t see how the existence of anything could be logically necessary. But some philosophers think that a perfect being is the kind of thing whose existence is logically necessary since the meaning of perfection must include existence. But apart from an ontological type proof, I think the form described above is the only option for a theistic proof. God’s existence can’t be directly experienced and so some form of (2) is required to demonstrate the existence of an unexperienced thing indirectly. Some form of (3) is necessary to know that the other being that must exist is a being different in nature than the one I experience. This step is necessary if we are ever going to get to knowing that God exists. (4) follows from the first 3 steps, and 5 is necessary to demonstrate that the thing that is different which must exist is indeed God. And so if any of the steps in this proof can’t be known, then it is reasonable to conclude that God’s existence can’t be universally proven. However, I am not convinced that any of these steps are known to be false, and therefore, I’m not convinced that theism is unprovable. On the contrary, an analysis of (2), (3) and (5) seem to indicate that these steps might be knowably true.

A thing that is changeable is a thing that has potential in its being. As a result, it must be possible for such a being not to exist. Since potentiality and actuality aren’t logically equivalent, it seems necessary for a distinguishing cause to exist in order to cause a potential being to become actual.

If every member in a set requires an actualizer to give actuality to that member, then every member would have to be an actualizer, and thus already have actuality. But a potential can’t have actuality without receiving it, and therefore it can’t be the case that every member already has actuality. Therefore, not every member can be a potential thing; there must be something without potentiality, something unchangeable.

If a thing can’t change in its being, then that thing can’t change from a mere conceptual potential to an actual potential. Thus, if it is actual, then it must not be a potential, and couldn’t have received its actuality. Neither can it stop existing since it is changeless. Thus, it must be eternal. If it were finite, then it would have potential to transcend its limits, but a changeless thing doesn’t have potential in its being. Thus, it must be infinite.

Now my cases for (2), (3), and (5) might seem a little confusing to someone new to these ideas, and indeed it might not be that even an expert really "knows" the validity of my reasoning. However, the nature and existence of my reasoning suggests that further scrutiny might yield a highly detailed proof for God’s existence, where each of the steps are readily known to be true by any rational person. As a result, I will conclude this essay by affirming that from my understanding of logic and ontology, it seems unreasonable to assume that no form of theism can be universally proven so that any rational person would know its validity by merely understanding it.