I've devoured everything I can get my hands on over the last 20 years pertaining to Near Death Experiences and am convinced it is not a hallucination. People pronounced clinically dead have reported too many verifiable facts that they could only have known had they indeed been witnessing events transpire in an out-of-body state, such as the actions of relatives and the specific procedures performed by doctors and nurses. While I have never had a NDE I have had several Out-of-Body Experiences and I proved to myself that it was not just a lucid dream. I saw people doing things in another room while out-of-body and after returning to my body, I got up physically to verify what I had seen. This could not possibly have been a hallucination, but people are going to insist that it must be a brain phenomenon because there could not possibly be such a thing as a "spirit". I've heard all about the neuro-scientist tickling the brain and producing hallucinatory sensations of light etc., but I don't think that explains it all. It certainly doesn't explain the reports of surgical procedures witnessed out-of-body that were later corroborated by the surgeons. It can't be a hallucination.