Great. But how do people manage to have differing ideas to begin with? I can't assume they're just dense and incapable of reasoning out the "right" answer; some of the most brilliant people I know disagree on some very basic things.
Consider the O.J. Simpson trial. Those jurors brought some non-rational baggage with them. Emotion, presupposition, prejudice, bias, agenda, policy, moral and aesthetic value unfortunately play too large role in our determinations of fact at times. Our failed attempts to find the truth in a reasonable, objective manner, without passion or prejudice, does not mean that there is no truth to find or that we can't know with confidence what the truth is.
Anyway, smart people differ on the question of God, for example, not because there isn't a right answer. God either does or does not exist, be sure. They differ at times due to both rational and non-rational factors. This is why it is better to be honest than intelligent when you approach a question of great existential import like the question of God.