There comes a time in the life of every human when he or she must decide to risk ‘his life, his fortune and his sacred honor’ on an outcome dubious. Those who fail the challenge are merely overgrown children, can never be anything else.
We have our hands, we have our brains, we have the challenge all around us, and we have within (from whatever source) the will to strive. That is enough; there is no need to assert 'belief' in that which we do not, as yet, know.