Quentin – had you read my previous post on this thread you would have noticed what you are stating here is a fallacy. There is a perfectly valid scientific experiment you can perform to prove that God exists, but atheists are unwilling to perform such an experiment. There is no point at which reason must be abandoned per se, although reason can be misused to explain away everything and deny evidence in which case it is not “reason” you mean but stubborn blindness. A leap of faith is not beyond reason per se either.