It is commonly assumed that there is no compelling argument for the existence of God. However, the argument for the existence of God is more compelling than almost any other argument about the fundamental nature of reality. The existence of God is more easily and convincingly demonstrated than the existence of other minds; the independent or objective existence of objects; or the real existence of subatomic particles.

In order to back up these claims, it is necessary to set out an argument for God’s existence. This is the first in a series of posts setting out an argument for the existence of God. The argument I will present is a form of the cosmological argument. The cosmological argument is hardly new. It dates back to ancient Greece, and its characteristic reasoning was set out in the Medieval period.

The form of the cosmological argument I will present, however, is primarily derived from the work of Robert Spitzer and W. Norris Clarke. Spitzer and Clarke both offer stripped down forms of the cosmological argument, which require less philosophical background knowledge than the more classical formulations of the arguments. This has the benefit of being more convincing to those who don’t want to spend years studying metaphysics. But it also has a downside: the arguments, though they do demonstrate the existence of a divine creator, say less about that creator than do the classical arguments.

The next post will give the first step of the proof. Before considering the proof itself, we should think about the nature of the certainty of arguments in general. Here are several levels of certainty an argument can attain.

A: Absolute certainty. No rational person could harbor any doubt, however small, as to the argument’s conclusion.

B: Satisfactory certainty. The argument is so convincing that no rational person could be unpersuaded. A reasonable person may be able to identify some doubts about the conclusions of the argument, but those doubts are so small, and the weight of the argument so great, that it would be irrational to deny the conclusion.

C: Relative certainty. A reasonable person can be certain that conclusion of the argument is better supported than any alternative. The argument is not airtight, but it is sufficient to establish that the conclusion is superior to any alternative.

D: Reasonable disagreement. The argument is sufficiently compelling that a reasonable person could reasonably believe the conclusion of the argument to be true. It is not so compelling that it would convince every rational person.

E: Moderate support. An argument does not compel one to a conclusion, but it nevertheless furnishes grounds that tend to support a conclusion.

F: Bad arguments. The argument does not establish its conclusion, nor does it furnish any ground that might lead a reasonable person to think the conclusion more likely.

Arguments can be more or less certain. It is a strange feature of the debate about the existence of God that many people presume that the arguments must be A-type arguments. For almost all other issues, however, we accept B or C type arguments as sufficient. Let me give an example.

Suppose that the argument from contingency presents a dilemma. Let us suppose, for the sake of argument, that the theist shows that either there is a God or things in the world came into existence without a cause. But the atheist, who accepts the dilemma, concludes that the theist has not show to an absolute certainty that the world didn’t just pop into existence without a prior cause. The atheist then concludes that the theist has not demonstrated the existence of God.

Let’s assume arguendo that the dilemma holds and that the theist has not established the first possibility to an A-level certainty. There may still be very compelling reasons to suppose that things cannot come into existence without a prior cause. Even if there is no mathematico-deductive proof of that thesis, it could still be the case that the theist show the conclusion to be compelling enough to convince any rational person.

The point is this. A possible objection does not mean that the argument is not convincing. One cannot offer an absolutely certain argument that we are not brains in a vat, for example. But arguments do not have to be absolutely, deductively certain to establish their conclusions. No major scientific theory rises to A level (or even B-level) certainty, for example. That does not mean they should be rejected.

In my view, an argument can be made that establishes that the existence of God is satisfactorily certain (B). Parts of the argument, such as the argument for the existence of an absolute, non-physical reality, rise to A-level certainty. But I will leave it to the reader to judge how certain the argument is as the series proceeds.