It is only necessary to be authentic in response. If I am worried about being faced with questions I cannot think of an answer to and that I will bumble and stutter an incoherent response, I just decide to let that happen, because that is a genuine response. It doesn't particularly matter if it happens, I still have the freedom to be an atheist even if I've argued my position badly. Atheists are under no more obligation to be rational, well-argued, or particularly articulate than anyone else. After any conversation with people who believe in god, it is highly unlikely that any of them will convert to atheism. And so what if they convert you? It's equally unlikely though. The important thing is that the decision is the individual's, not one forced onto the individual because they haven't performed particularly well in a debate.
The whole proof/no-proof debate is a bit of an irrelevance really. You could be presented with a valid proof of the existence of God and yet still decide for yourself that such proof must be an illusion, or indeed that your own identity is an illusion. We don't particularly need reasons for the positions we adopt, we just need to be reasonably comfortable in ourselves with them. The reasons and rational justifications tend to follow the position we take, not precede it. Take me for example, I'm an existentialist but I expect it'll be some years before I can robustly argue why.
The whole proof/no-proof debate is a bit of an irrelevance really. You could be presented with a valid proof of the existence of God and yet still decide for yourself that such proof must be an illusion, or indeed that your own identity is an illusion. We don't particularly need reasons for the positions we adopt, we just need to be reasonably comfortable in ourselves with them. The reasons and rational justifications tend to follow the position we take, not precede it. Take me for example, I'm an existentialist but I expect it'll be some years before I can robustly argue why.
