I am going to agree and disagree with you. That is not as fence-sitting as it may sound. I do agree that we do not need to prove empirically the existence of God. I believe (by the testimony of Paul in Romans and other places) that God reveals himself to everyone. Therefore, it is the denial of that revelation that marks the unsaved. Further then, testimony and life experience should have persuasive influence. However, the unregenerate mind thinks it holds to a higher standard when demanding a reasoned proof rather than testimonial proof. That's where Copleston and others shine. What the reasoned debate proves is not necessarily the existence of God, but rather the futility of the unsaved claiming a higher standard in reason. Even the best of non-Christian reasoned arguments cannot destroy the reasoned understanding of belief in God (or Christianity for that matter). To knock out a pillar upon which the unsaved mind is resting forces that non-Christian to grapple further with the idea of God. And that further grappling is what often leads to surrender and acceptance of God (e.g., C.S. Lewis).