Man should not believe in any notion which he is unable to disbelieve. For example, he who cannot disbelieve in god, should not believe in god. Such belief holds no value.
When I discuss religious or ethical matters with someone, I like to ask them: Are you capable of disbelieving? If you were proven wrong, what would that do to you?
Sometimes, belief seems like such a stupid thing. We use it to impose upon how things actually are with how we want them to be.
Otherwise, why believe?
If what is, is enough, then what remains to believe in?