"if life is common through the universe that would be evidence for atheism" > I disagree. I understand your point about chance and probability but a discovery that life is teeming would simply confirm that this is a life-producing Universe. We know that already. On the contrary, it could just as easily be an argument for theism: why would the Universe be (reatively) full of life-forms if there was no point to it all? - If one accepts human 'exceptionalism' then life isolated to the Earth makes a strong argument for theism. If life is everywhere then it is not unusual and it is simply the anthropic principal at work, and to me that perfectly fits atheism.