Given that near-death experiences happen with limited warning, they are almost impossible to test. “We’re dealing with a very short space of time,” [psychiatrist Bruce] Greyson says. A swimmer is trapped underwater, a roofer falls from a ladder, a bystander, peering down at their phone, is struck by a car.
In [his book After], Greyson points out that his career has coincided with advances in brain-imaging technology, including the emergence of fMRI scanners, which help neuroscientists observe thinking in action. But equipment like that requires compliance: an appointment is made, a patient agrees to sit still. What happens when an experience occurs randomly, nowhere near a hospital?
Greyson knows that events in near-death experiences are impossible to corroborate. “We can’t do research on a deity,” he says, drily. But still, he finds it tough to dismiss wackier theories, even if the data isn’t there. When I ask him what his current logical understanding is, he looks resigned.
“It seems most likely to me that the mind is somehow separate to the brain,” he says, “and, if that’s true, maybe it can function when the brain dies.” Then he adds, “But if the mind is not there in the brain, where is it? And what is it?”