Skeptics dismiss such stories as the effect of oxygen deprivation on the brain or some such thing. While some NDEs will admit of such an explanation, there persist in the literature some NDEs which defy natural explanation. As I mentioned in my post on the Unexplained, NDEs were one of the factors that led former outspoken atheist Patrick Glynn to abandon his atheism and believe in the existence of God and of the afterlife.
In The Spiritual Brain, Mario Beauregard and Denyse O’Leary shed some more light on this topic. They describe documented cases where people who were clinically dead said afterwards that they had an out-of-body experience (typical of many NDEs) in which they were able to accurately describe details of things that were happening to them while they were clinically dead. Detailed studies have shown that NDEs are more common than you might think. One study by Dutch cardiologist Pim van Lommel found that of 344 patients, all of whom were clinically dead, 18 percent afterwards reported having some sort of NDE, and 7 percent reported some sort of very deep experience.
But can an NDE transform a skeptic? Perhaps not. Philosophical atheist A.J. Ayer had an NDE, one which was somewhat negative (some cases of NDEs are negative rather than positive experiences for the person involved). When he died for good the following year he was still apparently an atheist. He did, however, exhibit some changes in his life after his NDE, another common effect of NDEs. Such changes often include greater compassion towards others and becoming a nicer person.
One philosopher, Neal Grossman, was arguing with a committed naturalist about NDEs. Beauregard and O’Leary record the exchange thusly:
Exasperated, I asked, “What will it take, short of having a near-death experience yourself, to convince you that it’s real?”
Very nonchalantly, without batting an eye, the response was: “Even if I were to have a near-death experience myself, I would conclude that I was hallucinating, rather than believe that my mind can exist independently of my brain.
Essentially, for the committed naturalist there is no amount of evidence, not even their own experience, that would persuade them to give up their belief in naturalism. In this sense naturalism is perhaps not that unlike a very fundamentalist religion.