I have to admit that there probably is a place for belief – in those situations where some deep inner conviction stemming from instinct or intuition convinces you that something is so, even though you can’t prove it. The problem lies with being sure that the conviction really does stem from instinct or intuition, and isn’t simply wish-fulfilment based on something you want to believe.
That’s one of the advantages of not claiming to know things: It’s easy to change your mind and it isn’t even embarrassing to say so. I still dislike earnestness, though. It’s smug.