Kalam cosmological argument
The Kalam cosmological argument is an ancient proof that God exists. It says that everything that comes into existence has a cause. The universe came into existence. Therefore the universe had a cause. That cause had to be outside the universe. Therefore that cause is God. Therefore God exists.Another way to look at this is that there had to be a beginning of time. If there was no beginning to time then time stretches out behind us infinitely, and if time before us is infinite then it is impossible for the universe to have moved through infinite time to get to where we are now. Time had to have a cause. That cause had to be outside time. Therefore God caused time to come into existence.
These are pretty robust arguments. I have asked many atheist about them but never heard a good resolution of them.
I am familiar with the Kalam cosmological argument (everything that begins to exist has a cause, the universe began to exist, therefore the universe has a cause), but I don’t know if I’d say that it’s a proof that God exists. It is, at best, proof that a deity of some kind exists, and to be picky, Kalam is a branch of Islamic philosophy so you might want to say “Allah” instead of “God” if you want to get that specific.
I am also familiar with the argument for a creator from the impossibility of an infinite. I’ll try and deal with both arguments at the same time.
First, let’s define our terms.
When we talk about our universe, I assume that you are talking about our universe — everything that science has, in principle, access to, or everything that came into existence after the Big Bang (assuming you recognize the existence of such an event). We are pretty certain that our universe came into existence, in that it apparently had a starting point. But if there is a universe (or some kind of physical reality, however you want to refer to it) outside of or before our universe, it is very hard to make statements about it. It would be difficult to prove that our universe is all that possibly exists or that any universe outside our universe must have begun to exist.
A cause is an action that precedes and leads to another action. We should take care when using “cause” in this context that we are not implying that anything which causes something else is doing so willfully. There can be unintelligent causes (as when lightning causes a fire).
Now, on with the discussion.
The crux of the matter, to me, is the assumption that there are no infinite series. Personally, I can’t see a logical way to escape the reality of some infinite series or another. Let me explain.
It is agreed that time in our universe began when our universe began. But did time exist elsewhere before our universe existed? Some people avoid the apparent paradox of an infinite past by saying that God is timeless. But this raises two problems.
First, I don’t see how the phrase “God is timeless” is meaningful. I don’t know that we can conceive of anything that exists without a time dimension. If you think such a thing is possible, then you need to explain.
Second, if God exists without time and time didn’t exist before our universe, then God could not have caused our universe. This seems obviously true when you remember that a cause must precede its effect, and until time exists it is impossible for anything to precede anything else. Putting it another way, saying “A happened before B” is a meaningless statement if time doesn’t exist. It’s like saying that an object with no dimensions is two feet tall.
So given this, either God must have a time frame of reference, cause does not have to precede effect, or the Kalam argument is wrong. If God has a time frame of reference, then it is infinitely long and we might as well posit the existence of a natural cause of our universe, one that has always existed.
There are possible solutions to the infinite-time problem that involve a time dimension that is circular instead of linear, but I’m not knowledgeable enough about theoretical physics to discuss them.