The problem is, logical argumentation regarding the question of the existence of God ALREADY presupposes HIS existence. In order to logically argue about the existence of God, one would have to, among other things, assume the universal, abstract, invariant laws of logic, which cannot be accounted for outside of God (and which are accounted for in the Bible). Please, however, feel free to posit another source for these laws, I shant hold my breath :-)