My Catholic father has really been hurt that I espouse atheism. He likes to say things like "You're not REALLY an atheist, because you celebrate Christmas. You put up a nativity scene!" When I say "Yeah, but I decorate with Santa Claus's, too, and I don't believe in him either." he (understandably) gets a little offended, and starts to go off on how Saint Nicholas was real.
Anyway, when I questioned him on "Why YOUR God, and not Hindu? or Allah? or Ra?" his response was that there are no other gods. All these different cultures are just worshiping the same ONE god in different ways. Kind of like a much much broader view of Islam, Judaism & Christianity all descending from Abraham.
How do you argue against that sort of approach? He was a biology teacher, and finds zero conflict between his faith & science. He believes that evolution is how god created us. He believes that science is the language with which god made the universe. He comes back to the "ultimate cause" argument (why something instead of nothing?). When I come from the perspective of a lack of evidence FOR belief, he goes to the argument from personal experience.
I've debunked a lot of his approaches about argument from design (that 'random' chance couldn't build a complex eyeball, it must have been designed to evolve that way - mental contortions anyone?).
Any thoughts on an effective way to support atheism in the face of generic "everyone is right" theism?