faith.

"There's a reason we refer to "leaps of faith" -- because the decision to consent to any notion of divinity is a mighty jump from the rational over to the unknowable, and I don't care how diligently scholars of every religion will try to sit you down with their stacks of books and prove to you through scripture that their faith is indeed rational; it isn't. If faith were rational, it wouldn't be -- by definition-- faith. Faith is belief in what you cannot see or prove or touch. Faith is walking face-first and full-speed into the dark."
-Elizabeth Gilbert from Eat, Pray, Love