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1. Introduction to Scientific Theories of the NDE
Although there are mechanisms in the brain involved in the dying process, science cannot conclude that consciousness is solely a product of the brain which ceases to exist upon permanent brain death. Science is unable to reach this conclusion because of the large amount of scientific evidence from near-death experience (NDE) research of consciousness functioning far removed from the body — a paranormal phenomenon called “veridical perception.” Although science cannot prove consciousness survives death, there has been important research on veridical perception (the AWARE II Study) which provides scientific evidence of consciousness surviving death and existing outside of the body.
A current theory of consciousness supports survival of consciousness after death by assuming consciousness is not localized in the skull at all. Consciousness could theoretically exist in the air waves much like an audio-visual signal which is received and processed in a television, for example. When a television is turned off, the audio-visual signal still exists in the air waves. In the same way, when the brain dies, consciousness may continue to exist outside of the brain. In other words, consciousness is not produced by brain, but is mediated by the brain. Continuing with this analogy, current materialist theories claim NDEs are only a product of the “television set” (the brain). Materialists assume that death is the end of consciousness much like shutting off a television ends a television program on the screen. But our analogy assumes the television show (consciousness) continues to exist in the air waves without an actual television to mediate it. Some of the top consciousness researchers, such as Dr. Stanislav Grof, believes this analogy fits. The following are some of these materialist scientific theories concerning the phenomenon of NDEs and why such theories fail to explain the phenomenon itself.
2. The Dying Brain Theory
This theory is one that has been popularized by Dr. Susan Blackmore in her book Dying To Live. (Read a critique of this theory). One of the greatest strengths of the afterlife theory and the argument that NDEs are real is also one of its greatest weaknesses. The fact that all those who had an NDE follow the same path toward the light, going through similar stages on the way, makes a powerful case for the whole thing being a profound spiritual journey to an afterlife where everyone, from all ages and cultures, is welcome. But that same case, the “sameness” evidence, is also a fundamental part of the argument that NDEs are not real experiences, not spiritual voyages, but a function of the dying brain. All brains, regardless of where in the world they come from, die in the same way, say the skeptics. And that is why all NDEs have essential core elements which are the same. The dying brain theory holds that these elements are not because the dying person is traveling toward a beautiful afterlife, but because the neurotransmitters in the brain are shutting down and creating the same lovely illusions for all who are near-death.
But why? Why should the dying brain do this, if it is just a highly sophisticated lump of tissue? That question is one of the most fundamental questions in the whole of human thinking. It boils down to asking, are we individuals with “personalities” and “souls” and “minds” that are exclusive to us? Or are we simply bodies controlled by very clever computers, or brains, each of which works a little differently from the rest, thus making each of us unique, just as an Apple computer is different from a PC, although there are far more similarities between them than there are differences?
Scientists and researchers are divided. There are some who want to reduce NDEs to nothing more than a series of brain reactions. Others, who accept the realness and validity of NDEs, are nonetheless quite happy to see it put into a scientific context. In other words, they are not frightened of researching the experience rigorously, of finding out everything that we possibly can about it, perhaps even being able to explain aspects of it. But they can happily let that scientific aspect sit alongside the deeply personal, life-enhancing evidence of those who have actually been there.
There are very few people around, even among the skeptics, who would deny that people have NDEs, and that they are deeply affected by them because so many obviously sane and well-balanced people have now come forward and talked about what happened to them. What they do dispute is what causes an NDE and what it means. There are two main strands of research: one takes the psychological approach, which looks for reasons for human beings to behave the way they do, and to think and possibly to hallucinate the way they do. The other is the straightforward physiological approach, which is searching for that part of the brain which malfunctions and causes an NDE. Increasingly, as in all brain research, not just that connected with NDEs, the two approaches overlap.
The ruthless, depersonalized argument – that an NDE is just the result of the brain beginning to die – is not acceptable to the vast majority of people who had an NDE. To reduce what was a profound and transforming experience to nothing more than a set of neurotransmitters going on the blink is a bit like seeing Michelangelo’s statue of David as nothing more than several tons of marble.
If there is no afterlife, and NDEs are just the last throw of a fevered and dying brain, why does it bother? If everything, including the soul and personality, is going to dust and ashes, why does the brain lay on this last wonderful floor show for people near-death, or facing actual death, who relax into peacefulness and describe their wonderful visions?
If NDEs are just a hallucination, why do a great many people report being told, “Your mission has not been completed,” or, “The time for your death is not yet,” during their NDE? If NDEs are just hallucinations, how can so many people be told the same thing in their hallucinations? Isn’t it odd that so many people are being told the same thing? Are they all hallucinating identical responses? For many people, it is easier to believe that NDEs are a real afterlife experience and not mass hallucination.
- Read an article supporting Blackmore’s theory. Read an excellent rebuttal of Susan Blackmore’s theory.
3. Charles Darwin’s Theory
One theory is that it is a deliberate ploy of the human race to help those behind adapt better to the inevitable ending of their lives. Charles Darwin‘s simple theory of the survival of the fittest holds that every species is struggling to increase its hold on this planet and guarantee the survival of its descendants. That is our greatest primary urge. Other animals help their peers to survive: the dying elephant, for example, trails away into the bush so that he does not slow down the herd. Are the dying just “helping the herd” by putting out propaganda that death does not contain a sting? But this theory does not explain why NDEs are erratic, or why we shunted down an evolutionary sidetrack for years by making them something that people were reluctant to talk about. After all, in Darwinian terms, humans are the most highly evolved intellectual life forms on Earth.
- Read an article that supports Darwin’s theory applied to NDEs. Read a critique of that article.
4. The Hallucination Theory
Some scientists from the camp that believes that NDEs are one day going to be explained by brain functions have suggested that the dying secrete endorphins, hormones which act on the central nervous system to suppress pain and which are known to create the “runner’s high“, which happens when long-distance runners go through a pain barrier and find themselves running with ease and without tiredness, and with a feeling of elation. But endorphins are not hallucinogens and cannot re-create a state similar to NDEs, so although they may be involved in the process as a painkiller, they are not responsible for the whole experience.
Research on neurotransmitter receptors is highly complex and, in terms of our understanding of the functioning of the brain, in its infancy. It is known that a powerful anesthetic called ketamine can produce many of the features of an NDE, particularly the out-of-body element, and one theory is that a ketamine-like substance may be released by the body at the time of an NDE, and may attach itself to certain neurotransmitter receptors and be responsible for producing the whole NDE by blocking those receptors.
A psychology professor named Dr. Ronald Siegel from UCLA rejects the spiritual and mystical importance of NDEs. He claims to have reproduced NDEs in his laboratory by giving LSD to volunteers, but, other researchers say that although drug-induced hallucinations may have some resemblance to NDEs, they are not the same. For one thing, drug induced hallucinations often evoke fearful and paranoid experiences which are not generally found in NDEs. Drug induced hallucinations distort reality while NDEs have been described as “hyper-reality.”
- Read more about Dr. Ronald Siegel’s hallucination theory. Read a critique of the hallucination theory.
5. The Temporal Lobe Theory
Some features of the NDE are known to occur in a type of epilepsy associated with damage to the temporal lobe of the brain, and researchers have found that by electrically stimulating this lobe they can mimic some elements of NDEs, such as leaving oneself behind, and the sense of life memories flashing past, although this is actually a common feature of NDEs. They believe that the stress of being near-death, or thinking that you are near-death, may in some way cause the stimulation of this lobe. There is some evidence to support this theory in the lower numbers of NDEs reported by people who suffer strokes which affect this part of the brain, or have tumors in this area. But there is also a case against: the characteristic emotions that result from temporal lobe stimulation are fear, sadness, and loneliness, not the calm and love of an NDE. Also, scientists may be simply discovering the mechanism connected with the mind/body separation thought by some to occur at death. Because a chemical mechanism is present in the brain, this does not mean NDEs are strictly chemical reactions. Science may only be describing the aspect of dying that deals with the brain.
- Read more about support for the temporal lobe theory. Read a critique of this theory.
6. The Lack of Oxygen Theory
Other possible explanations are a lack of oxygen in the brain, or too much carbon dioxide. But these would not explain why some patients are able to give full and cogent reports of things that went on around them during their NDE. Cardiologist Dr. Michael Sabom has reported one patient who, while having an NDE, watched his doctor perform a blood test that revealed both high oxygen and low carbon dioxide. Comparisons between NDEs and hallucinations produced by an oxygen-starved brain show that the latter are chaotic and much more similar to psychotic hallucinations. Confusion, disorientation, and fear are the typical characteristics, compared with the tranquility, calm, and sense of order of an NDE. There are some features in common: a sense of well-being and power, and themes of death and dying. But people who have experienced both at different times say that there is an unmistakable difference.
Hallucinations, whether deliberately drug-induced, the result of medication, or caused by oxygen deprivation, almost always take place while the subject is awake and conscious, whereas NDEs happen during unconsciousness, sometimes when the subject is so close to death that no record of brain activity is recorded on an electroencephalograph, the machine that monitors brain waves. Also, the medical conditions that take subjects to the brink of death, and to having an NDE, do not necessarily include oxygen-deprivation, or any medication. This is particularly true of accident victims. NDEs appear to occur at the moment when the threat of death occurs, not necessarily at the time, maybe hours later, when death is close enough to be starving the brain of oxygen.
- Read more about the lack of oxygen theory. Read a critique of this theory.
7. The Depersonalization Theory
The first modern attempt to explain NDEs in psychological terms was made in 1930 by a psychologist who argued that people faced with an unpleasant reality of death and illness attempt to replace it with pleasurable fantasies to protect themselves. They “depersonalize,” removing themselves from themselves – the floating away from their own bodies that experiencers report having. It is a theory that is still sometimes put forward, but it can be countered by the fact that some typical features of an NDE just do not fit into the depersonalization mode, such as the strong spiritual and mystical feelings, and the increased alertness and awareness.
- Read more about the depersonalization theory. Read a critique of this theory.
8. The Memory of Birth Theory
Another popular theory is that NDEs have nothing to do with death at all, but are memories of birth. A baby being born leaves the womb to travel down a tunnel towards a light, and what waits for it in the light is usually a great deal of love and warmth. What happens at the point of death is only a stored memory of what happened when life began. Yet again there are a lot of points that don’t match: a baby being born does not exactly float at high speed down a tunnel, but is buffeted along with difficulty by its mother’s contractions. And how does this model explain the meeting with friends and relatives who have died? The “Being of Light” is supposed to be the midwife or the doctor who rules the delivery room – but many babies are born without a midwife or doctor present, or perhaps with many people present. On a purely practical level, a baby’s nervous system is not sufficiently developed to allow it to assimilate and store memories of the birth process.
Those who support this theory say that the feelings of peace and bliss are a memory of the peace of the womb when all physical needs were met by the mother and there were no stresses and strains. Why should this be any more likely than the feelings of peace and bliss are relief from the pain of illness and injury at the point of death? However, being born is often not a pleasant experience for babies which leaves them crying as if in agony. In contrast, NDEs are more often described as the most pleasurable experience a person can have. The birth process is not pleasant.
- Read more about the memory of birth theory of NDEs. Read a critique of this theory.
9. The Afterlife Hypothesis
This website has a web page with a long list of scientific evidence supporting the Afterlife Hypothesis.
Dr. Melvin Morse, who did all the ground-breaking research with young children, states unequivocally: “There is no explanation for the light.”
Dr. Kenneth Ring, one of the most respected near-death researchers who has done much work of putting the subject of NDEs on the academic map, has this to say about the afterlife theory:
“Any adequate neurological explanation would have to be capable of showing how the entire complex of phenomena associated with the core experience [that is, the out-of-body state, paranormal knowledge, the tunnel, the golden light, the voice or presence, the appearance of deceased relatives, beautiful vistas, and so forth] would be expected to occur in subjectively authentic fashion as a consequence of specific neurological events triggered by the approach of death … I am tempted to argue that the burden of proof has now shifted to those who wish to explain NDEs in this way.”
Those sentences are a couple of complicated sentences, but what Dr. Ring is saying is that there are so many consistent features of NDEs that it is going to be very difficult to find a good explanation for them in terms of the physical working of the brain. And, he believes, that the evidence is so strong for them that sympathetic researchers should no longer feel that the burden is on to them to prove that they happen, but rather, for the skeptics to prove that they don’t.
Perhaps the final word should go to Nancy Evans Bush, an NDEr with the International Association for Near-Death Studies, who said:
“There is no human experience of any description that can’t simply be reduced to a biological process, but that in no way offsets the meaning those experiences have for us – whether it’s falling in love, or grieving, or having a baby” – or coming close to death and having a transcendental experience.
There is a “mountain” of scientific evidence suggesting consciousness can survive bodily death. Some of this evidence has been verified through NDEs involving “veridical perception.” Some of the evidence is spontaneous and circumstantial and of the kind that would stand up in a court of law. Some researchers have pointed out how science has not even been able to quantify consciousness, let alone trying to quantify the NDE. Scientists certainly lack the necessary tools to fully quantify and understand the nature of consciousness. The problem facing scientists in this matter is how consciousness can arise from a lump of goo (the brain) or how a conglomeration of atoms and molecules can produce the mind. Perhaps someday when science has discovered the true nature of consciousness, we may then be on the road to finding conclusive scientific evidence of an afterlife.
- Read more supporting evidence of the afterlife hypothesis. Read a critique of this theory.
10. Conclusion
In the end, science has come up with many ideas to explain NDEs. These include things like brain chemicals, lack of oxygen, and the mind trying to protect itself. But none of these ideas fully explain everything people report. Each one can explain some parts, but they often don’t match how clear and consistent these experiences are. They also struggle to explain how people can seem aware or even notice real things while they are supposed to be unconscious.
What we are left with is not a clear answer, but a deeper mystery. The evidence suggests that consciousness might not depend on the brain as much as we once thought. At the same time, science still doesn’t fully understand what consciousness is. This means our current ideas may simply be too limited to explain these experiences.
Studying NDEs calls for both humility and curiosity. Instead of ending the debate, the evidence shows we need to keep studying and asking questions. We should stay open-minded and be willing to rethink what we believe about the mind, the brain, and what it means to exist. Whether these experiences point to an afterlife or to processes in the brain we don’t yet understand, they make one thing clear: we are still at the beginning of understanding consciousness, and the final answer may be beyond what science can explain right now.
