I am a normal non-drug taking guy, and have never seen anything that has suggested that ghosts (or similar) exist, but I am open to the possibility that something that could give the illusion something like this exists could be there.
After all science does not explain everything and I think we are naive to say that just because we can't prove something exists that it does not.
I will explain the reasons of my post after some posts and votes.
One time I was trying to fall asleep and all of a sudden there was this flash of light and my face got all hot. I was freaked out and just kept lying there, then after a while it happened again. I actually went down to my parents' room and my dad was like 'Flashes of light? It means you're really tired. Go to sleep moron.'
It turned out that the light switch was kind of in the middle between on and off, and the window was open and the wind pushed the switch on every now and then. Or ghosts. My face getting hot was just a reaction because of the surprise I guess.
I have been to one of the most haunted places in Britain (Archcliffe fort) where loads of scary [censored] is meant to have happened. We went around at midnight with a load of people in to the depths of the fort with nothing but a lamp light.
They blatantly hustled us all. Complete FA happened.
You say in the OP that science can't explain everything and just because we can't prove something exists, its naive to dismiss it. You have this exactly backwards. Science can't explain everything, and just because we can't entirely DISPROVE something doesn't mean we have to give it credibility. No one is out trying to disprove ghosts because its impossible, many people are trying to show ghosts exist and none of them have. This is a lot of evidence that they don't exist, but either way, its far more reasonable to just refuse to believe in things until there is evidence, rather than believing in things until they are proven false.
/srsbiz
ZOMG like totally, I popped the ghost of your mom's cherry last night.