I’m replying to a request for more information on proofs of God’s existence.

First, let me point out that these are not “proofs” of God in the mathematical sense. There are no “proofs” of either God’s existence or non-existence, because proofs are always based on fundamental assumptions, and the question of God’s existence is so fundamental that no one can agree on a set of more fundamental assumptions. Rather, I am offering you arguments for God’s existence. Each argument offers you a choice; you are free to choose the alternative, if you can live with it. You’ll see what I mean as I continue.

I. The Cosmological Argument, or the Argument From First Cause

1. It is our universal experience that everything that springs into existence has a prior something that caused it to come into existence; that is, every effect has a cause.
2. It is now generally agreed that the entire universe, i.e. all of nature, including all space and time, sprang into existence at a specific point in the past.
3. Therefore, the universe had a cause, and that cause was necessarily not a natural cause, since all nature was the effect. Since the cause was not natural, it must be the only other possibility: supernatural.

You are left with several choices:

• You can reject premise #1, and claim that the universe sprang into existence from nothing!
• You can reject premise #2, and claim that the universe has always existed into the eternal past, a claim that rejects much of our current understanding of the cosmos.
• Or, you can accept that the universe had a supernatural cause. This cause can be called God, on the basis of its exhibiting the characteristic of omnipotence, or being all-powerful. This is far from the God of the Judeo-Christian Bible, but it does establish one of the fundamental features of the God of the Bible: His role as the creator of all things.

II. The Rational Argument

There are two classes of thinking: rational and irrational. Rational thinking is thinking that correctly relates to reality and truth; that is, rational thinking draws correct conclusions from correct data, where correct conclusions are conclusions that accurately correspond to reality. Irrational thinking, on the other hand, does not consistently draw correct conclusions from correct data, although even irrational thinking may “accidentally” arrive at a correct conclusion. For example, an irrational person may give the answer “five” for any mathematical question, but if that person is asked, “What is 2 plus 3?”, his answer will “accidentally” be correct.

Now, are the laws of nature rational? Clearly not, because no one claims that irrational people must be violating the natural laws. If anyone violates natural laws, it would be the rational thinker that overcomes the irrelevant forces of nature and, in spite of them, arrives at correct conclusions. So, it can be argued that rational thinking, if it ever occurs, must be driven by non-natural (supernatural) forces. That is to say, every rational thought has a rational cause, and that causal chain must extend back to the Original Rational Cause, which must be supernatural, since nature mechanistically obeys the irrational laws of nature.

Now, we humans are certainly not perfectly rational. We all think irrationally at times. But are we totally irrational? That is, do we ever use thought processes that draw correct conclusions from correct data?

Oh, oh. We’re in a quandary here. If we say that our thoughts are totally the product of mere irrational natural causes, and thus we are totally irrational, then our conclusions are also totally without merit. That leaves me unable to formulate a rational argument, and even if I were able, it leaves you unable to recognize a rational argument! So, it clearly is self-defeating to claim that we are totally irrational.

But if we exhibit any tiny modicum of rationality, that rationality requires a rational First Cause, which we call God.

III. The Moral Argument

For an excellent treatment of this topic for the layman, I would recommend the book “Mere Christianity” by C.S. Lewis. I credit that book with providing me with the foundation I needed for my Christian conversion. The following is my meager summary of that book’s thesis.

There are physical laws, and there are moral laws, and they are quite different in quality. Whereas the physical laws describe how things always behave (apart from the miraculous, which by definition violates the physical laws), the moral laws describe how things ought to behave. We don’t say that for every action there should be an equal and opposite reaction; we say that there is one. Likewise, we don’t say that everyone is kind to others; some moral systems say that they should be. But who gets to decide what the moral laws are? If we want to apply moral law to ourselves only, then I guess we could each make up our own set of moral laws (but if we’re each free to make our own moral laws, why would we? Why not leave ourselves free to do as we please?). But we’re more likely to apply our moral laws to everyone else, saying how unfair or corrupt others are. And we denounce whole cultures for their inferior morality, such as the Nazis or the Muslim extremists, or some primitive aboriginal tribe. But to claim that one moral system is superior/inferior to another, there must exist a universal moral standard against which to compare the two moral systems.

However, the natural world does not offer any help here. Nature does what nature does, period. There is no reason that it should do otherwise. No, if we want to find any basis for claiming validity for any universal moral system, we must claim that it is instituted from outside nature — from the supernatural. Once again, this would be the responsibility of God, the ultimate moral lawgiver.

Now, once again, this does not prove that God exists. You are free to renounce any obligation for anyone to do anything on the basis of morality, but if you want to impose a moral system on others, to be consistent, you must claim that your moral system comes from God.

IV. The Argument From Design

As a computer designer and one who is highly familiar with Information Theory, I find the Argument from Design to be among the most compelling.

Science is an inductive exercise. Induction is the process of taking as set of specific details (“the cats I have examined all have four legs”) and formulating a general rule (“all cats have four legs”). Deduction is the opposite; deduction takes a general rule (“all cats have four legs”) and deduces a specific conclusion (“Bob’s cat has four legs”, even if I’ve never seen Bob’s cat). The scientific method of induction is inherently error-prone, and thus all scientific conclusions are considered tentative; nevertheless, the application of the scientific method has yielded all manner of wonderful innovations that have improved our lives tremendously.

My experience, and the expeience of many others, is that whenever an entity asumes a highly improbable configuration, and that configuration performs an unrelated function, that entity is designed. Furthermore, it is universal experience that whenever the cause is known, such entities that exhibit design are caused a designer, and that designer is an intelligent agent such as a human. For example, when archaeologists find an object that clearly shows that it was fashioned to perform a function (such as scissors), that object is the product of an intelligent designer — a human.

Well, the fact is that we find huge numbers of examples in nature of items that exhibit this kind of specificity. DNA and proteins, which are the basis of every known form of life, are but one example of this kind of improbable specificity that we find in all life. DNA alone is sufficient to convince any open-minded observer that life is designed and thus the product of a Designer. That Designer cannot exist within random and undirected nature, and thus must be supernatural — once again, God.

V. The Ontological Argument

There is another argument type, called the ontological argument. Although many casual observers find it to be unconvincing, it is actually said to be the most iron-clad argument. In fact, Kurt Gödel, the man who upended the mathematical world in 1931 by proving that our practical mathematics is either inconsistent or incomplete, also formulated an ontological proof of God’s existence! He never published it during his lifetime, but his wife did so after his death.

I am not elaborating on the Ontological Argument here, for two reasons: you likely will not find it convincing, and I don’t fully understand it. if you wish to pursue it, you can find it here.

There are other arguments, such as arguments based on the historical evidence of the New Testament and the efficacy of prayer, that I must leave for another time.