There is nothing that comes into existence without a cause. From your innermost creative thoughts to a spot of mold on bread, to a new leaf on a tree, to the seemingly random emergence of a rain storm - all have a beginning and all have a cause.
Have you experienced something different?
But anyway, if there's a singularity (or suitable singularity-replacement) in both the future and the past you might be able to use something like Hawking's No-Boundary Condition theory to claim P2 is false.
Not that I do, but P2 is not rock-solid from a logic standpoint.
2) Since we exist, something had to have lead to us
3) The thing that lead to us was either lead to in turn, or "just existed"
4) If you don't accept that something can "just exist", that leads to infinite regress (before A there was B, before B there was C... on to infinity)
5) It's not too presumptuous to prevent infinite regress by saying "the universe" is what "just existed".
Since the possibility of the universe "just existing" was established by the previous reasoning, you can think if that's a reasonable stopping place when it comes to predictive power.
Hawking suggested it was though the "projection" he used for making the argument was complex and and don't fully understand it.
As far as I can tell, his argument was that the universe appearing to have a beginning was "merely" thermodynamic, and in the final quantum theory the beginning and the end would be closed, making the universe fully self contained. (Something about gravitational entropy fully canceling out all other entropy, making the universe sum to zero, with both the "beginning" and the "end" summing to the exact same value as each other (zero)).
Regardless, P1 is still required to make Craig's KCA work, because P2 is compatible with the universe just happening.
Editing to account for your later comments:
>There is nothing that comes into existence without a cause. From your innermost creative thoughts to a spot of mold on bread, to a new leaf on a tree, to the seemingly random emergence of a rain storm - all have a beginning and all have a cause.
That isn't quite the same scenario. The sort of causation we observe (which is actually compatible with no causation, a la Hume) is more like shuffling around of existing matter and does not translate to direct evidence for or against the hypothesis that something can come into existence uncaused.
I think when you combine the scientific evidence with the logic and continue down that line, you can make a good faith argument for an intelligent creator.
If you take quantum field theory, all reality spawns somehow out of immaterial fields without any cause.
Others from Advaita stream of thought have arrived at a place where the absolute is not God at all and don’t need physics to reason about that. In their terms we are all God with a problem of mistaken identity. Reality is already timeless, deathless.