"Not every theory has a proof but is still a valid theory that many yet be proven."

Perhaps we should be more careful with our vocabulary. In Math, a Theory holds an extremely exalted station in the Book of Laws *precisely because _it has been proven_*. It's much more certain and unquestionable - verily, by its proof it is unquestionable - than when we say more colloquially, "I have a theory about that." Most people, when they say that mean that they have something more like a Hypothesis.

And by Belief, I think you could say that you believe in gravity despite the fact that you likely don't have full knowledge of the subject. But that doesn't mean that it must be taken on Faith because there's a pretty significant body of evidence demonstrating its existence, and that it pretty well behaves precisely as, well... Theory predicts that it does.

You Believe gravity works. I Know it does. Fortunately for us, we're both right.