Much of the debate surrounding near-death experiences concerns veridical cases – instances in which the patient reports events that occurred around him while he was unconscious or even clinically dead. When these observations can be verified, they stand as strong evidence for some form of extra-bodily perception.

There is, I think, less debate about the non-veridical parts of NDEs – the celebrated trip through a tunnel or some other passageway toward a bright light, the reunion with deceased relatives in a paradise-like environment, the encounter with a Being of Light, the life review, and the decision (or command) to return.

Since these elements of an NDE cannot be verified by an outside observer, they are often seen as non-evidential. When a skeptical explanation is called for, the usual one is that the whole experience was a hallucination. We are told that the patient naturally hallucinated all this because he understood he was on the verge of death, a realization that triggered imagery based on his beliefs and expectations about life after death. In support of this theory, skeptics point out that there are variations in the reported experiences, and that these variations not infrequently involve cultural norms – precisely the sort of thing we might expect if the whole experience had been dreamed up.

I don't find this line of argument very convincing. I think it overlooks key facts and relies on implausible assumptions. Let's take a closer look.

First, is it true that everyone who has a near-death experience knows or believes he is on the brink of death? Actually, no. There have been numerous cases in which a person simply collapsed on the spot, with no warning and no idea of what was happening. These people were not in the hospital, they were not recovering from a serious illness, they had no particular reason to be thinking about their mortality. They blacked out instantaneously and then found themselves having a near-death experience. If they had no idea that they were in a medical crisis, why would their thoughts immediately move to imagery of the afterlife?

Perhaps it could be argued that people in a state of unconsciousness just naturally hallucinate about leaving their body and having a mystical experience. But why should this be? The spectrum of things about which we can fantasize, daydream, or hallucinate is unlimited. If NDEs were nothing but hallucinations, we would expect many of them to run along totally different lines from the classic NDEs that have generally been reported. We would expect the resuscitated patient to report that he was playing the piano at Carnegie Hall, or waterskiing, or delivering the valedictory address at his high school, or seducing a supermodel, or winning Wimbledon, or doing countless other things that people think about when their thoughts wander.

The range of possible hallucinations is probably no less broad than the range of subject matter for dreams. While certain types of dreams do tend to recur across the general population, there is also tremendous variety in people's dreaming. The same range and variety are not seen in NDEs. For the most part, NDEs fall into a much narrower range of categories, with obvious overlaps.

Moreover, even if we assume that the person's expectation plays some role in the experience (as I think it does), we are hard pressed to explain the many NDEs in which elements foreign to the person's beliefs crop up. Atheists with no expectation of life after death nevertheless have had "classic" NDEs. Some traditionally religious people have had NDEs that were largely or entirely devoid of religious imagery such as pearly gates, choirs of angels, and the figures of saints or Jesus. Often, the NDE is sufficiently different from the person's expectations that, upon recovering, he makes major changes in his belief system and lifestyle.

This is not to say that the NDE always surprises the experiencer. There are, for instance, a few well-publicized cases of traditional Christians who did indeed find themselves at the pearly gates. But this kind of thing seems to be the exception, not the rule. Don Piper, who had one such NDE and wrote a book about it, remarks at the end of his book that while he is sure his NDE was real, he is doubtful of most others, because they include "non-Biblical" ideas and images. And while his closed-mindedness is unfortunate, he is right that most NDEs are not Biblical or traditionally religious, even when the patient's own religious beliefs are highly traditional.

Perhaps most notable is the overall consistency of these reports. Skeptics, naturally, like to focus on differences among various NDEs. And there certainly are differences. Some people go through a tunnel, and others do not. Some people have an out-of-body experience in the hospital room or ambulance, and others remember no such thing. Some people encounter religious or spiritual figures, while others encounter deceased relatives. Some people have a life review, and others apparently don't. Etc.

But focusing on these differences tends to make us lose sight of the bigger picture. The NDE phenomenon, when viewed from a distance, is actually remarkable for the consistent pattern that emerges. Despite all the variations, the basic trajectory of the NDE is pretty well established and cuts across individual cases and even cultural lines. The person has the sense of leaving his body, approaching a bright and welcoming light, having a profoundly meaningful encounter with spiritual figures or loved ones (or both), and seeing his life from a new perspective (whether as the result of a detailed life review or simply as a result of the experience as a whole). When he finds himself back in his body, he typically feels somewhat deflated, even depressed, at the prospect of continuing his physical existence after having had a glimpse of "heaven." At the same time, he has a renewed sense of purpose, which often leads him to make profound changes in his life, including changes in career, religious affiliation, even his marital partner.

It is an open question whether some NDErs have different experiences than others, or whether some people just remember different parts of their experiences. Perhaps we experience – or remember – only what we need at that particular point in our development. Or perhaps it has something to do with the depth of the NDE, or with our state of mind at the time, or with the degree of physical recovery required after resuscitation.

But surely the general pattern that emerges is of greater significance than the relatively minor, albeit interesting, individual and cultural variations. The pattern is far more stable and consistent than would be be predicted if NDEs were simply the result of hallucinations in a brain gone haywire.

Some skeptics, acknowledging this issue, speculate that somehow the brain is hardwired to produce this experience under stress. There is no evidence to support this speculation. Nor is it clear how such a capability could have evolved in the first place, since it has no clear survival value and only kicks in when the person is dying (or very near death, or in a severe crisis). How could such a capability even be passed on from one generation to another, and what would be the point of it? Are we supposed to assume that, every once in a great while, a human being had a near-death experience but survived, and then produced offspring whose brains were similarly wired, and that this mutation was sufficiently valuable that it persisted and spread throughout the entire population? In what way would such a mutation have any biological utility? How would it increase any individual's chance of survival and reproduction?

Or perhaps we are supposed to assume that this hardwiring is a mere fluke, a random development that somehow took hold across our species even though it offers no particular evolutionary advantage. There are evolutionary developments that seem to be essentially pointless and random, yet persist for no clear reason. But it strains credulity to think that an experience as rich, elaborate, and meaningful as an NDE is a purely random byproduct of evolutionary change. If the experience were indeed random and arbitrary, then its content could be almost anything; yet, as we see, the content tends to be reasonably consistent and to follow the same general pattern or structure. What is more, the content and pattern are consistent with our highest spiritual yearnings and aspirations. If it is a fluke, it is an astoundingly beneficent one.

And there is one more thing. Not only are the general features of NDEs reasonably consistent across the population, but there are striking consistencies in matters of detail. For instance, it is often stated that communication in the next world is carried out by means of thought rather than spoken words. Cities with buildings that appear to be built of glass or some other transparent or translucent material are frequently described. Gardens with flowers in incredibly bright colors, including colors that cannot be described or reproduced on earth, are a common element. Deceased relatives are often seen in their prime, decades younger than they were when they died, and sometimes younger than the NDEr even remembers them. The life review is often described as an interactive experience in which the person feels all the pain or joy he caused others, even down to specific incidents, such as a playground bully experiencing what it feels like to be punched in the nose. People who report out-of-body experiences very often say that their perception was sharper than any earthly perception, that their visual perception was panoramic and covered a 360° range, that they could read minds, that they could pass through walls at will, that they could almost instantly travel to any place they were thinking of. They also frequently describe their confusion and disorientation upon looking down at their own body, which initially they don't recognize because they are accustomed to seeing themselves as a two-dimensional image in the mirror.

Many other details could be cited. The point is that the consistency of these reports goes beyond general patterns and features. Are we really supposed to believe that the brain is somehow hardwired to make us think we have entered a heavenly environment of iridescent flowers and glass cities in which telepathy is the common mode of communication?

It seems clear to me that the hallucination theory fails, even if we set aside the evidence from veridical NDEs. Of course, when these are taken into account, the hallucination theory comes even more untenable. But that's another story.