The Cosmological Argument is based on scientific evidence for a Creator:
Premise: That which begins to exist must have a cause.
Premise: The universe began to exist
Conclusion: The universe has a cause.
There isn’t much room to maneuver here. The first premise is simply logical. Every event in our existence has a chain of causality. We may not always know what the cause is, but we know that there must be one. Further, if you deny the law of causality, then science is impossible. Intuitively, we know that if a major event like the Big Bang happens, there must be a cause.
The second premise is a relatively recent scientific discovery. Most scientists favored a steady state theory of the universe. Even Albert Einstein thought that the universe should be eternal. He introduced a cosmological constant into his theory of relativity that he later called the biggest blunder of his career. The equations of the Theory of Relativity pointed to a non-static universe and he added a constant to make them static. Modern science points to a non-eternal universe. Our universe began during what scientists call the Big Bang. The first evidence for this was discovered by Edwin Hubble. He found that the farther away a galaxy was, the faster it was moving away. Georges Lemaitre realized this was consistent with an expanding universe. Scientists realized the obvious implication of this is that if you go back in to history far enough, it all started out at the same point.
Another piece of evidence that supports a finite universe is the Second Law of Thermodynamics. The gist of it is that in a closed system energy always flows in one direction, from low entropy to high entropy. You can make it go the other way, but you must expend even more energy to do so. The sun is radiating energy out into space. This radiation supports all life on earth, but we know that it will run out some day. Like putting toothpaste back into a tube, it would be impossible to get that solar radiation to flow the other direction. That is increasing entropy. The implication is that the universe cannot be eternal, because if it were, the universe would have run out of energy long ago. If you walked up to a car with the engine running, you wouldn’t assume it had always been there, because it would have run out of gas. The Second Law of Thermodynamics is as close to you can get to what is known as “settled science”. The Second Law also rules out an eternal cycle of big bang followed by big crunch, or an expanding universe that slows down and eventually collapses, starting the cycle over again. This is reinforced by modern cosmology. Not only is the universe expanding, but is is accelerating, not slowing down.
It is almost certain that the universe had a beginning. Therefore, the universe must have a cause. There is nothing in the known laws of physics that allow for the universe creating itself.
The conclusions that can be drawn about the cause will be the topic of Part 2.