Watching death

What happens when we die? Surely everyone wonders about this very human question, and it's certainly caused much dissent between religion and science. While most scientists think that death must be the end of personal consciousness, most religious believers expect their soul or spirit to survive.

How can we find out the truth?

We know that roughly ten per cent of people who come close to death have "near-death experiences" (NDEs) in which they seem to travel down a dark tunnel towards a bright, warm light; see their body from above; experience vivid memories; and even enter another world or meet gods, angels or spirits. A few have mystical experiences of oneness with the universe, or experience the dissolution of the illusory self.

All these experiences can be accounted for, in principle, by disorganised activity in the dying brain. Yet this argument does not convince believers who argue that after all the brain activity stops, the soul or spirit still carries on.

Then there are claims that NDEers have observed details of the accident scene, hospital ward, or medical apparatus that they could not have seen with their physical eyes because they were unconscious at the time. These claims depend critically on timing, with believers saying the experiences happen during unconsciousness or clinical death, while sceptics argue they occur just before or afterwards. But without any means of timing the experiences this cannot be tested.

Some experimenters have placed concealed targets in cardiac care units, hoping that patients close to death may be able to see them, so proving they have really left their body, but no positive results have been obtained. This is what the sceptics would expect but is no proof that they are right.

So the impasse remains.

The most important experiment that's never been done is to take fMRI or PET scans of people as they die; either those who really do go on to die, or those who suffer clinical death but are resuscitated. If this were done we would be able to test theories about how NDEs and mystical experiences are generated in the dying brain, and answer questions about the timing of the experiences. Perhaps even this would not resolve the final question once and for all, but it would certainly bring us a lot closer to knowing what happens when we die.

And why has it not been done? Because when someone is dying it is far more important to try to save their life than to do a scientific experiment. Nevertheless it could be done, and I hope that one day the technology will be so unobtrusive and easy to use that the ethical problem will disappear and we will be able to watch the dying brain as easily as we can now watch the living brain.

I think it would help us face death with more equanimity."

Dr Susan Blackmore is a freelance writer, lecturer and broadcaster, and a Visiting Lecturer at the University of the West of England, Bristol.