Someone in my CFI online class asked me what the best strategy is for discussing faith with a Christian. What would you say? My response:
There are so many Christianities there is probably no one single way to proceed. You just have to start listening. I like to provoke at least enough doubt that they will read a book or two on it by atheists. I like to quote other Christians against each other. That has shown itself to be effective since it's not pitting their particular faith against atheism.
I like to show weaknesses in the Bible and the theology that comes from it, most notably its superstitious nature and the barbaric nature of Yahweh. My claim is that once the brain of the believer is divorced from the Bible he or she probably wouldn't believe at all.
One guy sent me a supposedly new cosmological argument for the existence of God. I responded by asking him if this is the reason he became a believer in the first place. He had to say no. So I asked him what were his initial reasons for believing in the first place, saying this question is much more important to me than anything else. He didn't like this at all. He wanted to debate this new argument of his. I asked because people who became believers in their different religions probably stated out young in their faith as taught by their parents in their respective cultures. Since the adult attitude is skepticism they ought to re-examine these reasons as an outsider or non-believer would. For if one's faith cannot be accepted by an outsider with such a perspective, then that particular God would be found condemning people for simply being born in a different culture, and that's unreasonable for a reasonable type of God.