01 October 2010

Rebirth and the Scientific Method

I've been involved in a desultory discussion via comments on the blog Buddhist Geeks on the subject of reincarnation and the scientific method. This was sparked by a blog post entitled An Evidence Based Spirituality for the 21st century. In it Charles Tart argues for a scientific approach to ESP and reincarnation (Tart seems to prefer this term to 'rebirth') based on what he considers to be "solid evidence". I have a life-long interest in science, and studied it at school and university. Having invoked the scientific paradigm I think that Mr Tart needs to follow through on the implications of it, and here I will explore some of the them. I want to look particularly at reincarnation from two different points of view - methodological and philosophical - and show that we are far from having a scientific account of reincarnation.

The Problem of Method.

Mr Tart cites some 4000 cases collected at the University of Virginia Medical School, where research and publication continues on this subject, especially by Dr Jim Tucker. Tucker's informants, as Tart says, are children between the ages of 3 and 6; and the 'evidence' is the testimony of these infants. So already we must register some concerns. The theory of mind, the ability to distinguish others as self-conscious individual beings, only develops at around 3 or 4 years. Very young children like this have some difficulty distinguishing self from other; truth from fantasy; memory from imagination; overheard conversation from their own thoughts. So we must doubt their reliability as witnesses. As in legal cases, how one questions very young children has a strong determining effect on the answers you get. We could not accept this kind of 'evidence' without detailed scrutiny of the method - something which would be time consuming and beyond the scope of a blog post. For instance one group of researchers looking at children's evidence in sexual abuse cases conclude:
"It is now acknowledged that persistent suggestive questioning can lead children to provide accounts of events that never occurred, even when they first denied them. Sometimes the questioning results in the child developing a subjectively real memory for an event that never happened."
Such conclusions are widely replicated across a number of different disciplines over the last couple of decades. Even in adults memories are very plastic and subject to change; and subject to invention; imagination can come to seem like memory. Stories repeated by family members can come to seem like personal recollections, even when we weren't there, or born yet. Often the way we recall a situation depends on the emotions associated with the memory. This is why anecdote is seldom invoked as evidence by scientists. The fact that most of the informants are under six may well mean that after that age the distinction between fantasy and fact becomes clearer, or that the children are less able to be lead by enthusiastic researchers with something to prove.

The claim is often that the person could not possibly have known the details of their account from personal experience in this life. Having just trashed anecdote, I'll risk hypocrisy by sharing something from my own life. For years I had memories from childhood which involved an unaccountable knowledge of and respect for Buddhist monks. As a child I understood what meditation was, and once or twice sat down to meditate. It has a lot to do with why I was attracted to Buddhism as an adult. I grew up in a small town in New Zealand and I could not possibly have had contact with Buddhism in my childhood, as far as I know there were no Buddhists within a hundred miles. There was no way for me to have such knowledge from this life. Or so I thought. Last year I started re-watching the old TV show Kung Fu, and realised that this was the source of my 'memories' - it all came flooding back. I'd loved the show as a kid, 30+ years previously, but had simply not made the connection partly because so many years had passed.

If someone, especially a young child, says that they remember a past life, or even if they only appear to have a memory which cannot be explained, that is not the same thing as them actually having had a past life. How would one establish beyond any doubt that a so-called memory was of a past-life? We can easily accept the idea that people have a memory that they cannot account for; but why assume a past-life is the best explanation for this?

I propose this test: one of these people who recalls a past life could predict some previously unknown historical fact, that could then be shown to be true by previously unknown archaeological finds. Get the subject to make a prediction, publish it well in advance of the search, and then go off and dig and find some previously unheard of city or civilisation which substantially confirms the predictions of the person. A variation on this procedure might including getting the person to predict the discovery of the previously unknown species recorded in the fossil record, and then discover a fossil just as described. Or they might show how to read a previously undeciphered script. Something that only a person living in that time and place could know, and that is entirely unknown to us now.

The value of a scientific theory is in the predictions it makes. I would be very interested to hear about any peer-reviewed publication in which a past-life recollection told us something new about the world in the way that I've outlined.

[7 May 2014 - a thorough assessment of the methods and conclusions of another reincarnation enthusiast, Dr Ian Stevenson can be found at the Skeptics Dictionary.]

Philosophical Problems.

The basic contention of Tart et al is that empirical methods can be used to demonstrate metaphysical ideas or perhaps we should say 'abilities' such as extra-sensory perception or recollection of past lives. They are saying that such ideas are demonstrable and measurable, and therefore not really metaphysical, i.e. not beyond physics. However there is a kind of placebo effect at work: ESP is only detectable if you believe in it in the first place. Presumably this is what has gone wrong in all of the properly controlled studies which have shown absolutely no evidence in support of ESP and the like. On the other hand there is also the fact that a desire to believe has allowed charlatans to pull the wool over the eyes of the credulous in a number of cases. The best known, and funniest, of which is the Project Alpha, a hoax perpetrated by some (sleight of hand) magicians which exposed the credulity, and poor methods, of ESP researchers.

When, in 1915, Einstein proposed that gravity is better understood as the bending of space by masses, it might just have remained another novel idea if Arthur Eddington had not demonstrated in 1919 that it is indeed the case. Eddington's observations of the transit of Venus demonstrated that masses bend light, which itself has no mass, as it passes close by them. In the face of this kind of evidence, the world then accepts this new idea even though it is counter to the prevailing view and even counter-intuitive (how can something with no mass be affected by gravity?). The same thing happened with Quantum Mechanics which was not accepted without some fierce opposition lead by none other than Albert Einstein, and now underpins the technological revolution. The same thing is currently happening in cosmology as empirical evidence accumulates that the universe must contain more mass than we can see or our theories predict (dark matter), and that something is pushing galaxies away from each other (dark energy).

Sometimes paradigm changes can be theory led, sometimes observation led. However the empirical side of things is based on published observations which are then repeated by an independent third parties, who often have a vested interest in proving their rivals wrong! It is the build up of repeatable results that creates the pressure to change a world view - and let's be clear that our views of the world can and do change from time to time. The dark matter/energy observations will eventually change our understanding of the cosmos for instance. So called 'cold fusion' by contrast could not recreated in any of the labs which tried, and it soon became apparent that the announcement had been premature to say the least. ESP has being researched for 200 years without coming up with one uncontestable result, while at the same time many frauds have been exposed.

Reincarnation fans complain that if scientists would only apply empirical methods to the study of reincarnation they would see it is real. But equally if a scientist reports a negative result it is because they are too materialistic, and not open to new ideas (tell that to any astronomer or nuclear physicist of the last century and they might beg to differ). Usually an unequivocal negative result requires a scientist to abandon their theory (e.g. phlogiston, or the æther) and seek a new explanation.

There is a much greater philosophical problem with so-called memories of past-lives, and it is one that plagues all theories of rebirth/reincarnation. Such theories suggests a continuity between lives, over multiple lives, a personal continuity. This raises the question about the nature of that continuity? There must be some aspect of our being, not reliant on our physical body, which goes from life to life, collecting and preserving memories, and then later allowing our present consciousness reliable access to those memories, though apparently only during childhood. What can survive intact through multiple lives and deaths, and accurately preserve memories? I know of nothing which would meet the requirement except a soul of some kind.

Now, if science is to offer any insight into the phenomena at all, then it would be in establishing the existence of, and the mode of functioning of this soul-like phenomena which provides a medium for memory storage external to the body, and particularly the brain. They would show how and where such memories are stored. Of course they must take into account the well demonstrated role of the brain in the formation, storage and recall of memories of living humans - we can lose all of our memories and the ability to make new ones through brain injury. (I recommend Joseph LeDoux's book The Emotional Brain for a survey of the history of this field). The idea that memories survive the death of the entire brain, and surface sometime later in a person with no close genetic relationship, requires explanation. Tart et al, having invoked the scientific paradigm, must seek to explain it within that paradigm. It's up to people like Mr Tart and his colleagues and supporters to come up with the theories that can be tested, with measurements that can be made. As I understand it they do not propose mechanisms for metaphysical memories. They do not propose theories that can be tested. They merely churn out anecdote. It is not sufficient for the idea to be taken seriously to invoke the "50 million Elvis fans can't be wrong" argument.

In Conclusion

I think it is only right to be sceptical towards the idea of recollection of past lives. It is a deeply problematic metaphysical belief. It will not be easy to demonstrate that life continues after the death of the individual, and as far as I know this has yet to happen. My view is that a belief in past-life recollection is more than likely linked to a deep desire for personal continuity. It's poignant, it's understandable, but it is entirely unscientific. By invoking science the meta-physicians are caught out. If the phenomena is material enough to be observed then it must either obey known laws, or we must recast those laws to account for it. But if it really is as described in faith texts, then it is not dependent on the material world and will be forever beyond the reach of empirical science. So why invoke the scientific method in the first place? I will have to leave this question hanging, but it is one I must come back to. The conflict between the ancient world views preserved in the amber of religious faith, and the modern empirical world view is on-going.

Update: 10.10.2010
Anyone interested in the way memory works will be fascinated by this story from the Guardian Newspaper: Meredith Maran: Did my father really abuse me? It is an extract from her book My Lie: A True Story of False Memory, which looks at the way one intelligent and articulate woman manufactured 'memories' of incest out of a febrile imagination, on the basis of her deep (and positive) involvement in the issue of sexual abuse, and a culture which demonised men. I don't think this in any way trivialises the issue of sexual abuse, but it does give us insights into the complexity of the mind, and memory in particular.

Thanks to my friend Vidyavajra for bringing this to my attention.

Update 24-7-11
This cartoon on Calamities of Nature is apposite. As it says: either souls interact with the world and are within the province of science; or they do not, in which case why should they concern us?
Update 7 May 2014
Sean Carroll a real scientist talks about life after death: Physics and the Immortality of the Soul
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