Since publishing my essay on the existence of God, I have wanted to provide a concise summary of the argument.
Why do I do this? It is because when I see the trees and the stars, realizing the transcendent genius which was required in order to create them, I hear a voice saying to me, “I love you.”
The classic cosmological argument for the existence of God rests on the premise that whatever begins to exist – that is to say, anything which is not past-infinite, anything which is not eternal – must have a cause for its existence. But even before one considers whether or not to accept that premise, it is useful to observe that there are really only four possible scenarios for the origin of the universe. This can be clearly seen from the following set of necessary propositions.
Either the universe had a beginning, or it didn’t.
If the universe had a beginning, then either it had a cause or it did not have a cause.
If the universe did have a cause, its cause likewise either had a beginning, or it didn’t.
Those three binary possibilities are exhaustive; that is, there are no other possibilities. This leads to four possible origin scenarios.
- Possible scenario #1.: The universe did not have a beginning; that is, it has always existed.
Modern science has shown this simply not to be the case. There is a scientific consensus, based on extensive observation, that the universe had a beginning approximately 13.8 billion years ago.
- Possible scenario #2.: The universe had a beginning, and it popped into existence out of nothing, uncaused.
This is not logically impossible, but it is implausible because it violates the principles of causation, which affirm that nothing happens without a cause.
- Possible scenario #3.: The universe had a beginning, and it was caused by some separate entity which itself also had a beginning.
This too is logically possible, but it entails an infinite regress of non-eternal causes, since one must then ask, what caused the cause, and then, what caused that cause, etc., etc. If the regression is infinite then it begs the question: how did the regression begin if it did not begin with an eternal cause? The only way for the regression not to be infinite is for it to come sooner or later to a cause which had no beginning, which is equivalent to the fourth scenario.
- Possible scenario #4.: The universe had a beginning, and it was caused by some separate entity which did not itself have a beginning – that is, the cause of the universe was some eternal entity. This is one step from theism. Theism does not entail any of the difficulties inherent in the other possibilities: it has not been falsified empirically, it does not violate the principles of causation, and it does not beg the question. Thus, theism is truly the only plausible explanation for the existence of the universe.
Scientists believe that all matter and energy, along with space and time themselves, came into existence about 13.8 billion years ago. If so, and if the universe had a cause, then the cause must have been immaterial, timeless, and immensely powerful. The Fine-Tuning of the universe shows that the cause was a conscious, purposive Agent of incomprehensible intelligence. These are some of the attributes which science shows the Creator possesses, to a virtual certainty, and now we have come all the way to theism. God exists.
There is another basis for concluding that the Creator is a personal entity. If that were not the case – if the cause of the universe were some physical state of affairs existing from eternity past, then all of the conditions needed for the universe to come into existence would themselves have existed from eternity past; and if so, then there would have been nothing to prevent those conditions from producing the universe at some time in the infinite past. And if that had occurred, then because of the Second Law of Thermodynamics, which states that in a closed system entropy (disorganization) always increases with time, the universe would already have reached heat death. It has not done so; therefore, the cause of the universe could not have been a purely physical state of affairs existing from eternity past.
 This is the first premise of the cosmological argument. For a more complete analysis of this premise, see joshualetter.com/blog, June 28, 2018, page 11.