"...of course if you have personal experience of the metaphysical it stops being a presumption....."

nope...it might a dream... or last night's Sauerkraut. Various 'religious' experiences were reported a couple centuries ago that were later shown to probably due to hallucinogenic spores in the air. (I can't find the specific reference right now.)

What is sure is that people 'usually' do not invent these experiences...they HAD an experience, and it is part of their memory and must be dealt with. What is NOT clear is status of the the origin or cause or explanation attributed to them.