That's the nature of the scientific enterprise. As Isaac Asimov put it, people once thought the world was flat, then they thought it was a sphere, but if you think the latter is just as wrong as the former, you're more wrong than both. Aw jeez, not that old argument again. Atheism is not a leap of faith, it has no real content at all, it's just a refusal to accept a claim on insufficient evidence. Everybody's an atheist to some degree. I suggest , for instance, that nobody believes in Zeus or Thor anymore, but in their day they had followers just as convinced as any contemporary Jew, Christian, or Muslim, and each of those groups bears a degree of atheism toward the claims of the others. By far the simplest explanation for such things is that all religions are human inventions and none of them are right. When you truly understand why you don't believe in Zeus and Thor, you'll also understand why I don't believe in the deity claimed to be common to Judaism, Christianity, and Islam. We're all atheists, I just reject one more deity than most people do.