I used to go with my grandma, years ago when I was a kid at primary school. What I remember is it was dead dull and not a bit like the seances you see on TV. Actually, that is the point - it should be dead dull. I actually used to find 'real' church more interesting. At least you sometimes got an interesting sermon.
All beliefs about the supernatural are impossible to 'prove'. For example, if you could prove beyond doubt that by being a good Catholic you would definitely go to heaven, everyone would be a good Catholic. (Or whatever.) Faith is something you have or have not, and if you have, no amount of logic will destroy it. It's a bit like supporting City.
