William James calls that error "medical materialism". This "too simple-minded system … finishes up Saint Paul by calling his vision on the road to Damascus a discharging lesion of the occipital cortex, he being an epileptic. It snuffs out Saint Teresa as an hysteric." Paul may well have had an epileptic episode. But that's only to say that there is a biological component to all human experience. "Scientific theories are organically conditioned just as much as religious emotions are; and if we only knew the facts intimately enough, we should doubtless see "the liver" determining the dicta of the sturdy atheist as decisively as it does those of the Methodist under conviction anxious about his soul."
http://www.guardian.co.uk/commentisfree/belief/2010/oct/25/william-james-religious-experiences
