If you take the outside view, and account for the fact that sixty-something percent of people don’t believe in Christianity, it seems like (assuming you just learned that fact) you should update (a bit) towards Christianity not being true.
If you did know the percentages already, they should be already integrated in your priors, together with everything else you know about the subject.
Note that the majority of numbers are not prime. But if you write a computer program (assuming you’re quite good at it) and it tells you 11 is prime, you should probably assign a high probability to it being prime, even though the program might have a bug.
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.