Joe no longer fears death. In fact the last time it happened he rather enjoyed the ride. First he was plunged into darkness, then came a bright light, a field of flowers, and a man in white who told him about his future. Later doctors informed him that his pulse had been flat for 44 seconds.

For Joe his near-death experience (NDE) was a very real preview of what is in store for him after death. Science has a different take: NDEs are real, but they have nothing to do with the afterlife. Instead, they are illusions created by a fading brain. But despite numerous attempts, no one has been able to scientifically explain all the elements of an NDE.

Now one researcher thinks he can. For Kevin Nelson, a neurophysiologist at the University of Kentucky in Lexington, NDEs may be little more than dream-like states brought on by stress and a predisposition to a common kind of sleep disorder. If he’s right, as many as 40 per cent of us could be primed to see the light.

Written accounts of NDEs go back more than two thousand years and have been reported all over the world. Most include a “point of no return” that if crossed will lead to death, and a person who turns you away from it. The identity of the person seems to depend on your religion. Christians, for example, often meet Jesus or a dead relative while Hindus may see Yamraj, god of the dead.

For Nelson, this suggests that NDEs stem from something fundamentally human. “People say that because there’s a common thread running …