Tuesday, December 30, 2014

Near death experiences and evidence in support of the theory of life after death

A recent edition of the Unbelievable radio show (on 6th December 2014) looked at near death experiences and out of body experiences. Unusually, for the Unbelievable show, there was no Christian guest on the show. This made the discussion and debate somewhat different from usual, in that there was no defence of the Christian viewpoint in the show. And there was no anti-apologetic either.

The show featured Eben Alexander, a former non-believing neurosurgeon who had a "near death experience" (NDE) while in a coma and has written a couple of books about it. The experience has convinced him that consciousness does not require a functioning brain to exist in, that is, that the conscious mind will exist after the brain ceases to function. In other words, the experience has led him to believe in life after death. But he isn't a Christian. 

Also on the show was sceptical psychologist Jane Aspell, who thinks that Alexander's experience was purely a creation of the mind, and not evidence of consciousness outside the brain. Aspell contends that Alexander's 'journey' was, essentially, a creation of his subconscious mind as he was coming out of coma, not an experience he had during the time he had "no brain function".

Apparently (according to Eben), the visions he had must have coincided with the time he had "no brain function" because the vision included six people who were there when he was in the coma, and who weren't there at a later stage. Well, actually, only five of the six were there during his coma, the sixth wasn't there, but is apparently relevant, for some reason not explained in the show. I'm afraid this sounds a bit like special pleading. A vision of six people which supposedly corresponds to a visit of five of them doesn't sound like great evidence. Maybe it is, but Eben's response to questioning on this issue was "buy my book, I've discussed all the evidence there", which doesn't make for great debate.

So the discussion was inconclusive. Alexander had a vision, but didn't manage to persuade the audience that it had to have been during his "no brain function" period, so the jury has to be still out on that one. Meanwhile Aspell's explanation for the whole thing sounds compelling and really quite reasonable.

Also on the show was Graham Nicholls, an out of body experience (OBE) researcher who claims to have been having out of body experiences all his life. He is also not a Christian. He gave some hand waving examples of 'real' out of body experiences he has had, but came across as quite a credulous chap. Basically, willing to believe almost any story of 'evidence' that is presented to him.

What he (and Alexander) seem to think is that evidence which is consistent with a hypothesis necessarily lends support to that hypothesis. For example, Nicholls' remote viewing of a cathedral in Tallinn (I think that's where it was) was taken by him as 'proof' that OBEs are real.

The issue is that this is only half of the rigorous scientific method. In order to count as 'evidence' for any given hypothesis, an event or observation must also count as evidence against any and all rival hypotheses. If an observation is equally consistent with all possible hypotheses, then it lends no weight to any of them. This is the essence of Bayes's Theorem, which I've blogged about before.

In other words, if someone claims to have had an OBE, the story of their experience only counts as evidence if it contains elements which are inexplicable by 'natural' explanations. In Nicholls's story of the OBE involving Tallinn cathedral, the 'observation' of the scaffolding on the hidden side of the cathedral could only count as evidence in favour of OBE if there was no physical way that Nicholls could have seen the scaffolding before, and no way that anyone could have mentioned it, and no way he could have seen something about it on TV or the internet, etc. Given that it is almost impossible to prove that one doesn't know something, or didn't know about it before a given point in time, this hardly counts as evidence.

The possibilities in this case are (a) that Nicholls had a genuine OBE, and therefore OBEs are real, or (b) that Nicholls hallucinated the whole thing, possibly based on things that he 'knew' prior to the hallucination (perhaps he only knew these subconsciously), or (c) that Nicholls is an intentional fraudster. Note that neither (b) nor (c) entails that OBEs are either true or false.

The 'evidence' of the story as presented in the Unbelievable show is entirely consistent with all three hypotheses, so really counts as evidence in favour of none of them. Given that we have quite a lot of other evidence for people being fraudsters or deluded, but limited evidence in favour of OBEs, our reasonable conclusion cannot be in favour of the existence of OBEs based on this. Maybe other evidence will present itself, but certainly nothing presented in this radio show was strong enough to give support to the OBE hypothesis.

No evidence is not proof against any theory. No evidence is simply no evidence.

Finally, I have to comment about the flawed reasoning behind the premise of the show. It seemed to be taken as read that evidence of out of body experiences, or brain activity during the "no brain function" period, or other 'near death' experiences would in some way count as evidence for the possibility of life after death. Why should this be? The thing is that NDEs are always recounted by people who return to conscious life after the experience, similarly with OBEs, the people telling the stories are always back in their own bodies and clearly not dead. The conscious mind is always tied to the body which it inhabited before the experience. We know nothing, precisely nothing, about what happens once the link between conscious mind and living body is actually severed. Maybe the conscious mind can continue (somehow) after this, maybe not, but as far as I know, we have no way of investigating this. Well, not by talking to the living anyway...

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