ATHEIST: Well, as Carl Sagan said, why not just save a logical step and say that the Universe is eternal and has always existed. It had no beginning and thus no need for a beginner.
THEIST: As I said, the overwhelming scientific evidence points to the Universe having a beginning.
ATHEIST: Then, your “evidence” for a god or gods becomes dependent on scientific understanding, which is, by definition, subject to change. Suppose science finds that the Universe is oscillatory. This Universe ends and another begins in an infinite cycle into the future and the past.
THEIST: So, crudely we could imagine time being bent into a circle in your picture of the Universe.
ATHEIST: Yes, although I prefer the image of a Mobius strip.
THEIST: Whatever geometry you choose, I still ask who made the circle or strip?
ATHEIST: Whatever answer I give does not solve the problem, it only moves it around; the question still remains: Who made the maker?
THEIST: Well, I believe God is eternal; he has always existed. We know our observable Universe well enough to know that everything here has a beginning, but God is transcendent. He is outside of our Universe, so we cannot just assume that he had a beginning.