A near death experience (NDE) consists of a variety of sensations reported by people who have nearly died or have been revived after being clinically dead (clinical death being defined as lack of blood flow to the brain and subsequent shutdown of cerebral cortex function).

The following description of a Western NDE is a composite construction that is intended to give the reader a general idea of the basic elements that can be found in the experience:

I could see myself lying on the operating table and heard the doctors say that I had died. A tunnel opened up before me and I felt myself rushing towards a place of light. I entered the light and was overcome by a great sense of peace. Here I met God who passed judgment on my life as it flashed before my eyes. I felt I had a choice of either staying or returning to life, and decided to return because my family needed me. I then felt myself re-enter my body.

NDEs are reported in approximately one-fifth of persons who experience clinical death (usually from cardiac arrest) and, as shown in the above generalization, can be broken down into eight broad stages:

Obviously, those who survive and can relate their NDEs have had brain activity occurring at some level and, in my opinion, this is the most likely explanation for the phenomena.

I shall begin by giving an outline of probable factors res-ponsible for the basic elements of the experience. This shall be then followed by an explanation of why NDEs are coherent rather than fragmentary phenomena.
 

Auditory awareness is not dependent on cerebral cortex function as it occurs at lower level brain areas that remain functional when higher brain areas are not. Consequently, it is still possible for an unconscious person to hear and remember conversations. Indeed, several experiments have been conducted where doctors have acted out surgical crises, and the patients under anaesthesia have been able to recall what was said with various degrees of accuracy.
 

People who are undergoing a traumatic event can mentally separate themselves from the experience in order to protect their psyche. This defensive mechanism may have a chemical basis – some features of NDEs can be engendered by the anaesthetic ketamine, and this may indicate that the brain produces a chemical (possibly encephalin) with similar effects during traumatic events.
 

This effect may result from the random firing of neurons in the visual cortex due to anoxia (lack of oxygen in the brain). Computer modelling shows that this results in a white light appearing in the central visual field that expands in size as oxygen deprivation continues, thus creating the impression of movement towards the source.
 

Anoxia can also affect the limbic system (amygdala, hippocampus and hypothalamus), the seat of emotion. It is possible that the sense of peace and euphoria experienced during an NDE may be the result of changes occurring in this area of the brain.
 

The perception of other worlds and beings upon reaching the light may arise from the brain’s attempt to make sense of the effects of anoxia (see "coherence"). Under conditions of near death the brain is virtually isolated from the external world, and consequently the inner world of the mind is now the only reality. These factors combined with the prevalence of belief in some kind of afterlife and judgment of one’s actions may account for the phenomena.
 

Experiments where the temporal lobes (a region of the brain involved in memory) have been stimulated with electrodes has induced in many subjects the experience of reliving memories, out of body experiences, and even the sensation of moving through a tunnel towards a light. When the temporal lobes of the brain are subject to anoxia, neuro-transmitters are released and massive electrical activity ensues. This increased electrical activity may play a role in the generation of NDEs.
 

Why do people experience NDEs as a coherent event rather than as random sensations and images? First of all it is important to keep in mind that several areas of the brain are probably involved. For example, experiments involving the stimulation of the amygdala, hippocampus and temporal lobes – all of which are interconnected – produced feelings of depersonalization, hallucinations and dream-like states infused with religious themes, visions of God, demons and ghosts.

Dreams may provide some insight as to why NDEs are coherent. Dreams are caused by the random activation of thoughts or ideas that have usually been prominent in the mind of the individual during the day, and it is the neocortex that attempts to make sense of this data by putting it into a coherent form, thus giving rise to a kind of theatre of the mind in which the dreamer can participate.

With NDEs an individual may have an awareness of the possibility of death at a conscious or subconscious level at the time of illness or danger. Consequently, ideas associated with death, the afterlife, and God etc. may come to the fore. The neocortex then orders the hallucinations produced by anoxia, neuro-chemicals such as encephalin, and sensory deprivation into a coherent pattern based on the individual’s cultural background and personal expectations concerning the afterlife.

That these hallucinations seem real may be, as previously suggested, due to a lack of sensory input from the external world – the brain is deceived because it has lost contact with the external world and has no reference point for reality.

The above explanations rely heavily on the assumption that anoxia is the primary trigger for NDEs. This, however, may not be totally correct. For example, psychologists Emily Williams Cook, Tan Stephenson and Nicholas McClean-Rice at the University of Virginia examined the medical records of forty NDE cases, and found that less than half of these people were actually in a truly critical condition. Their conclusion was that the fear of death might trigger these experiences. In view of these findings, the affects of anoxia may be only a partial explanation for what is a very complex phenomenon.
 

One problem with the idea that NDEs are perceptions of an extant transcendental reality is the observation that people's religious traditions and personal expectations appear to influence what they perceive.

For example, an analysis of NDEs in Thailand has revealed an absence of those phenomena commonly found in Western verities, as can be seen in the following composite construction (based on case histories) that is intended to give the reader a general idea of some elements that can be found in the Thai experience:

I had been sick for several days, and was lying in bed at home when a yamatoot [a servant of Yama, Lord of Death] suddenly appeared before me. He said he had come to take me for judgment, and it was then that I knew I was dead. Grasping me by the hand, he led me out of my house and along a path.

After some time we came to the house of Yama. We entered the building, and the yamatoot presented me to the god. The Lord of Death looked at me and then opened a book in which the names of those who had died were written. He then spoke to the yamatoot and said "You have brought the wrong man. You must take him back."

I then found myself back in my own bed.

From studying these accounts, the basic differences between Thai and Western NDEs can be listed as follows:

Studies of Hindu NDEs have also revealed basic differences:

Out-of-body experiences are rare, as is the tunnel phenomena (the afterlife is accessed by walking). Intense feelings of joy and ecstasy are absent, and whereas their deceased mother greets most Westerners, Hindus are more likely to encounter a male relative, possibly reflecting the low status of women in Indian society. Also, Hindu deities or beings interpreted as such predominate.

In Japan, researchers at Kyorin University studied the experiences of seventeen patients resuscitated from comas caused by heart attacks, strokes, asthma and poisoning. Eight patients could recall experiences that they referred to as "dreams", many of which featured rivers or ponds. There were no reports of out-of-body experiences, tunnels or a sense of euphoria.

In Melanesia, a similar situation predominates with the Kaliai people of Papua New Guinea: The deceased walk into the afterlife and encounter ancestral spirits or beings derived from traditional mythology. Visions of heaven are consistent with Cargo Cult beliefs – the idea that the spirit world is rich in European technology. There is no life review and judgment often consists of personal vindication with punishment meted out to hated enemies, especially those suspected of being sorcerers.

It is important to note that most of the non-Western NDEs (Japanese reports excepted) did not occur in hospitals, were not triggered by cardiac arrest, and that most recipients revived without medical intervention. In view of this fact, it is probable that many of these individuals were in a death-like trance where pulse and breathing fell to undetectable levels. Indeed, the absence of factors common in Western NDEs seems to indicate that the limbic system may not have played as large a role, possibly due to the absence of anoxia.

Indeed, this variety of experience appears to be induced by the person’s death-like state or possibly their fear of death that, in turn produces hallucinations that are ordered by the neocortex and shaped by indigenous religious traditions and personal expectations.

These natural explanations may be sufficient to account for NDEs, However, no essay on this subject would be complete without considering the possibility that they are supernatural events. Consequently, I shall now address this claim.
 

Supernatural explanations for NDEs rely on the concept of the soul – the idea that human beings possess an immaterial mental essence that is capable of surviving bodily death.

The problem with this idea can be seen when we ask how an immaterial entity can interact with the material world. For example, we can see objects because light is reflected from their surfaces and enters our eyes where an image is formed on the retina and converted to electrical impulses that flow via the optic nerve to the visual cortex of our brains. Indeed, all extant objects are experienced through our sense organs, and without them we can form no impression of the external world. In view of these facts it is difficult to see how a disembodied mind could perceive the body it inhabits from a birds-eye point of view.

Nevertheless, the American cardiologist, Michael Sabom, claims that patients have been able to accurately describe the behaviour of needles on monitoring equipment when they appeared to be unconscious. Unfortunately, experiments by other researchers have failed to confirm the ability of unconscious patients to perceive aspects of the physical world through channels of perception unknown to science:

As previously mentioned, another problem with the idea that NDEs are perceptions of a transcendental reality is the observation that what people experience is influenced by their religious beliefs and personal expectations. Of course, those who believe that these events are more than a variety of hallucination may argue that there are many transcendent worlds – Christians go to the Christian Afterlife, whilst Buddhists go to the Buddhist Afterlife.

The problem with this idea is that no religion is as old as humanity. For example, where did the souls of those people who died 40,000 years before present go? Furthermore, when Buddhism and Christianity arose how did their respective heavens arise? Did a committee of gods decide to construct them, or did they automatically crystallize out of some kind of transcendental Materia Prima due to the collective beliefs of each religion?

If so, does this mean that if I believe the afterlife is a blue void in which floats a titanic crystal pyramid of many levels, each inhabited by golden beings of superlative excellence, that this reality springs into existence, or must I convince a certain number of people before it happens, and if so, then how many?

I have raised all these questions to illustrate the fact that supernatural explanations are inadequate because they raise more questions than they are capable of answering.

Furthermore, investigators cannot objectively test any answers to these questions because transcendental worlds are inaccessible to natural channels of perception, and any experience of these realms is an entirely subjective event incapable of independent verification.
 

Although aspects of NDEs require further elucidation, and those explanations given in this essay may prove to be wrong in the light of further research, the view that they are supernatural phenomena is less likely to be true than natural explanations.

This conclusion is based on the observation that these experiences are moulded by the percipient’s religious traditions and personal expectations. In my opinion, this indicates that they are most likely mental events that bear no relation to any extant transcendental reality.

Bibliography

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