Well, I suppose it's technically possible. It's odd that no psychics have ever managed to heal anyone in the past, so I don't think it's worth banking on.
If you're healed, of course it can be proven to others. That's how we know psychics have never managed to heal anyone. They're like homoeopaths in that respect.
How is it proven except solely to the person done too? given word spreads of it, the 'psychic' wouldn't have a minute to him/herself and rather keep it on the down-low (omg he/she has the power to heal but they are just watching tv now!! when im really sick and need to be healed, like the other billion out there).
The 'psychic' works their magic and presdo they are healed. The person who is healed rings his friends n family saying a 'psychic' healed me, they either;
a: say bs, where did u go
b: bs, you're just lucky
c: see i told you it would just go away
d: ok whatever, a psychic healed you.. can i get a prescription of the drugs your on too?
and finally maybe
e: holy **** i dont believe it, your actually better, a psychic has this power? take me to them please!
probably some more i missed too lol.
