No sooner was [Abraham] weaned -- and he was but a small child -- that his mind began to seek and wonder: How do the heavenly bodies orbit without a moving force? Who moves them? They cannot move themselves! Immersed amongst the foolish idol-worshippers of Ur Casdim, he had no one to teach him anything; his father, mother and countrymen, and he amongst them, all worshipped idols. But his heart sought, and came to know that there is one G-d... who created all and that in all existence there is none other than Him. He came to know that the entire world erred...
Maimonides