As I established in previous blog entries, the Near Death Experience (NDE) is no mere delusion. But neither is it a glimpse into Heaven. It is entirely subjective, occurring within the brain of the person experiencing it. It is a highly structured, detailed, and intense subjective experience. It is something that the brain does in extremis, that is, when imminently threatened with death.
This immediately raises the question of how the capacity for humans to have such a highly structured set of brain experiences could have evolved. Natural selection cannot, after all, favor something that occurs just before death, since the person who experiences them cannot leave offspring.
I wish to suggest that the Near Death Experience evolved because it offered a fitness advantage to people who experienced them and then returned to life. Consider what would have happened back in cave man days. A warrior was killed. Then he came back to life! And he had such things to report! Such visions! Clearly, he had some special contact with the gods. He would be rewarded with high social status and all of the additional mating opportunities that this would afford. Something similar could have happened to any shaman, male or female, who might have gone a little bit too far with the Salvia divinorum or the mushrooms.
Someone who had mere delusions from a brush with death would not be nearly as credible as one who had specific and credible visions such as those associated with the Near Death Experience—credible enough that people still believe them, and books about them are best sellers even in an age of science.
It has been noted that people from many different cultures have similar near death experiences. While it is possible that this is because they have all seen Oprah, it could also be because the brain-based capacity for experiencing a near-death experience had already evolved before the common ancestral populations of all modern races left Africa about 100,000 years ago, before modern races had differentiated.
I have, therefore, offered in this series of blog entries first a medical then an evolutionary explanation for the Near Death Experience. It is neither mere delusion, as skeptics often claim, nor is it a glimpse into heaven.