Hallucinations:
Hogan
1. Incredibly accurate and verifiable information results from the NDE that would not result from a hallucination.
2. People on drugs who have NDEs actually see fewer deceased relatives when they travel out of body. This suggests that people who do see relatives are clear minded, not hallucinating.
3. People see deceased relatives but not living relatives in their NDEs. In some cases, children see dead relatives whom they had never met or seen pictures of. That could not result from a hallucination.212
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Turning to the question of whether the NDE was a hallucination (the most common skeptical argument), they [Sabom and Ring] both noted that a hallucination is accompanied by heightened brain activity. But their studies produced data showing that NDEs happened more often when neuroophysiological activity was reduced, not increased. Sabom also found that NDEs were more likely when the person was unconscious for longer than 30 minutes; Ring found that the closer people were to physical death, the more extensive the NDE.213
near-death.com See section below on brain chemicals.
Long
The percentage of time that people encounter deceased relatives is extremely high. It was actually 96% in the NDERF study and only 4% of near-death experiencers met beings who were alive at the time of the near-death experience. That’s actually corroborated by another major scholarly study which found it was 95% of the time that they encountered beings they knew from their earthly life that were deceased.
The important thing is that any other experience of altered consciousness that we experience on earth, dreams, hallucinations, drug experiences, you name it; all of these other types of experiences of altered consciousness, a vastly higher percentage of people are going to be alive at the time of their experience.
You're going to remember the banker that you did business with that day or your family member you said hi to as you were walking into the house. This is what's in the forefront of consciousness. So for people to so consistently encounter deceased relatives is very, very strong evidence that they are, indeed, in an unearthly realm and it certainly points to evidence of an afterlife.
...
People in general, all other hallucinatory events, dreams, all other temporary, transient, even pathological alterations of consciousness are essentially never going to result in that high a percentage of people experiencing them going on and have those types of profound life changes that we see in near-death experiencers.
And moreover, what you see in the life changes of near-death experiencers is markedly consistent. In other words, it’s not just that they have life changes; it’s the consistency of those life changes. The substantial majority, if not overwhelming majority of near-death experiencers believe that there’s an afterlife. They believe that there’s a God. They no longer fear death. They’re less materialistic. They value loving relationships more. The list goes on and on. I consistently observed, not only in the NDERF study but from scores of prior scholarly studies of this phenomenon over 30 years.