Ok, perhaps English is not your first language, Hettie? In any event you seem very good at selecting parts of people's posts and being all arsey based on that, whilst failing to grasp the overall argument.
Sorry to cut and paste, but I really can't be arsed with typing it all again.
I don't believe ghosts are the spirits of the dead. But I believe people see "ghosts". "Ghosts" are either imagination, atmospheric/environmental conditions, electromagnetic fields, low frequency sound, drugs, alcohol, being asleep/semi-conscious, collective hysteria, grief, or another function of the brain.
I don't believe mediums receive messages from spirits of the dead. I think some of them have a gift of sorts which is being very good at noticing things and 'reading' people.
I think some of them know their gift for exactly what it is, deliberately make it all "woo" and exploit people - proper charlatans.
Others have the same ability but genuinely believe they are receiving messages from the dead and don't deliberately set out to defraud or take advantage of people.