At a point in human history, we developed a spiritual belief system based largely on geographical cirstance?

If only one of those belief systems is correct, does it not render all of the others useless? Human beings make mistakes...say you're a legal defender of your belief system in a court of law, and prove to me that your belief system is correct, beyond the shadow of any doubt, by using education, common sense, science and reasoning only--no quotes from any doctrine of any kind--like a real courtroom with real world evidence.