Most of what you know, you learned from other people, directly or through books or something. Proving things like "the Earth goes around the Sun" are very difficult if you don't take other people's word for it. You've heard that there are experiments you could run and calculus you could do to show that the Earth going around the Sun fits a model, but odds are you haven't done them and if we pick the right experiment, you won't even know how you would go about proving it. That's not an insult. I just think that human knowledge is too broad for there to be any Renaissance men anymore. Usually, when I say this, someone gets upset about the fundamental difference between testable and untestable ideas. I get the difference. But we actually, personally test such a small fraction of the things we believe, I don't think it's right to act like our personal knowledge is entirely based on logic, reason, and the scientific method. Believers and nonbelievers are both human beings and they come to their beliefs by the same mechanisms - one of those mechanisms is faith. Somethings works for you or you been told it works, so you have faith that it will keep working.
