I will start with the assumption that logic itself is valid, because as a human being I cannot do otherwise. There is technically no reason whatsoever to make this assumption, because if logic is invalid, then logic could be both valid and invalid with no contradiction whatsoever, because any contradiction would be solely a logical contradiction, and logic is invalid. To argue that logic “makes sense,” or that we see it happening all around us, and that it agrees with the outside world are all simply begging the question. These arguments use logic to prove that logic is valid, but if logic itself is on trial, logic cannot be entered into evidence. However, if logic is invalid, both sides of this argument fall apart, and I have no clue whatsoever of how to proceed with an argument if logic is invalid, so it must be assumed, if for no other purpose than for the sanity of the human race.
Thus, starting from logic alone, we know that either the universe exists or it does not. There is no third alternative. We perceive that the universe exists. If the universe exists, then either it has always existed or it has not. If the universe has always existed, either nothing has ever happened or every conceivable possible occurrence has already occurred an infinite number of times, and the mere thought of a “present” is mere nonsense, because there is no way to point to a specific point along an infinite line as viewed, theoretically, in its entirety. Infinity is infinity, and any finitude associated with it is simply nonsense. An infinite yet changeable being is thus a nonsensical construction (sorry Hindus). Thus, the universe must have had a beginning.
Now, so far, I have only proven that which is already commonly accepted, or at least given lip service to. However, the evolutionary hypothesis is that a tiny speck (presumably a singularity) once contained all mass in the universe, and it exploded into the universe. This returns us to the argument of finitude or infinity: either this singularity has existed for eternity or it has not. If it has, then the Big Bang has happened an infinite number of times (we can say for certain that it didn’t not happen, because the world exists), and the thought of “this particular occurrence,” and thus a “present,” and therefore time in general, is completely meaningless. If it hasn’t, then the logical law of causality states that something else must have caused it. If this singularity represents the entirety of the universe at this point (which it both does by hypothesis and must, due to the previous argument of finitude and infinitude, which I will not repeat yet again), then this cause must be outside of the universe. In this case, there is really no point in developing the idea of the Big Bang, because there must still be a “super-natural” cause of the universe.
So the universe is finite, with a beginning and end, and as such requires that something have created it. Now, I could stop there, and just leave it as yet another modified version of the law of causality, but all this has actually just been setup for the “real” thing I have been trying to get to: this whole argument applies to any object to which time can be applied. If a thing is temporal, it is either eternal and unchangeable (in which case it also could not affect anything outside of itself, because that would require it change–it would have to be a completely passive object, completely disconnected from the outside world, and it is strongly questionable that such a concept even makes sense to coexist with any other entity, unless every other entity with which it coexists is precisely such as it), or it is finite, in which case it had a cause. Thus, the fact that the universe exists today means that it had a first cause, and that first cause must, by necessity, be outside of time, or it itself would need a cause. Thus, the mere existence of the universe, or even my own existence as a being (apart from any sensory data, just the raw fact that cogito ergo sum) requires the existence of a being that exists outside of time, that created this universe. And any being that creates a self-contained universe will, automatically, have complete and total control and knowledge of everything that occurs within that universe (think of an author writing a book: nothing happens in a book without the author’s knowledge, consent, and active causing, and if the author stops writing the book, the universe in the books simply ceases to exist at the point at which the author stopped writing).
Conclusion: the universe is finite, God exists and created the universe, He is outside of time and the universe, and He is omnipotent and omniscient with regard to the universe.
I could go on to derive other characteristics of God, but I will stop there, because that is all that comes to me spontaneously, without me specifically trying to intuit other characteristics of the Author Being.