St Augustine said ‘Understanding is the reward of faith. Therefore seek not to understand that you may believe, but believe that you may understand.’ Another way of putting it is not to say, ‘seeing is believing,’ but rather ‘believing is seeing.’ C.S. Lewis said that the year he found faith in God was the same year he learned to dive. On reflection he thought that there was some significance in that. Plucking up the courage to launch yourself headfirst into water is an amazingly difficult thing to do, the first time you do it. Your brain tells you that there is no problem in it, but your fears hold you back. Finally, after numerous feet first jumps and then half-hearted belly flops, you pluck up the courage and you actually do it.
So it is with our faith. We take that first leap and then we need no proof; we just know.