The British newspaper, The Independent, reported the death experiences of a man who "died" twice, once after a motorcycle accident and once after a drug overdose. In both cases, his experience was exactly the same.
On the sensation of death itself:
"I had no idea, it was just black emptiness. No thoughts, no consciousness, nothing.
"Both times I was just "not there". It was just all black. I would
describe it as when you take a nap. A short nap with no dream, you wake
up and it feels like you've been sleeping a long time, when in reality
it's only been about 15 minutes.
"The only reason I know is because the doctors were obligated to
share the information with me. "So yeah, you were dead for a couple of
minutes, just FYI" hahaha.
"So if the doctors wouldn't have said anything I would've just thought that I took a dreamless nap."
On the experience itself:
"It was definitely not just a gap. Much like a dreamless nap, you
don't just wake up and feel like time just jumped ahead. You know that
you've been asleep for a while. At the same time, you can't really
remember experiencing anything at all, unless you had a dream.
"So yes and no. I experienced something, and that something was nothing."
On his religious viewpoint and his experiences being dead:
"I have always been an atheist, but I have always had a part of me
that hoped there was a God or Heaven or something greater than us. I
mean, who wouldn't want there to be a Heaven?
"I am still an atheist, and now I know that there is no such thing as
God or Heaven. At least not for me. My reasoning behind that is no God
would ever put a person and family through such a experience.
"I am an Atheist, and always will be. But I believe that your belief
is your belief. The only thing we can share is our own experiences and
let people make up their own mind. People need to stop forcing their own
beliefs onto others."
On death itself:
"Death is death. Once your dead, that's it, it's over."
This is an report of one person, whose statements cannot be confirmed by science. However, when dealing with such experiences in the past, medical providers have been told by other "dead" patients of seeing a white light and a sense of being floating upward.
It may be a question of subconscious belief memories kicking in as a defense mechanism.
But if this man's account is taken as fact, then the premise of LOST, with its life and death symbolism such as the sideways world, is totally false. It would bring the premise of the series more in line with the dream state or coma theories, where the brain is still processing information to the conscious self.