Some of my favorite Christian works are all about doubt, but the conclusion tends to be faith is the only way. The Catholic priest in the movie may raise his hands during the thunderstorm and shout angrily at God to show himself, but what saves him is the "leap of faith" where he realizes that God will never give you proof of his existance - it's more sophisticated, but it's still the folksy blind faith.

Many Christians believe that you must believe in Jesus to get into heaven. I prefer what Proust said (paraphrasing - the actual quote I can't find and is far more beautiful): "Who is more likely to get into heaven - someone who believes in god, despises and judges the world and mankind or someone who loves all of gods creations without judgement but doesn't believe in him?" I refuse to think a loving god would make the litmus test such an arbitrary thing.