Wednesday, November 19, 2008

Mind-body panel 2: Bruce Greyson - "Brain and mind don't seem to be the same thing"

Dr. Bruce Greyson is the Chester F. Carlson Professor of Psychiatry and Neurobehavioral Sciences and Director of the Division of Perceptual Studies at the University of Virginia Medical School, and author of The Near-Death Experience: Problems, Prospects, Perspectives. He is also the editor of the Journal of Near-Death Studies.

Philosopher Elie During asked Greyson,
I think it's clear that what is being tested by those who, like yourself, are investigating cases of near-death experiences is not so much survival as much as it is the degree of dependence of consciousness on the brain. The functional relation between consciousness and brain activity can be probed within this limited temporal lapse, when things happen that seem to loosen up the ordinary connection between the two. Again, the hypothesis being tested is not a straightforward metaphysical hypothesis—that of the substantial existence of a conscious entity fully independent from the body. And yet, we cannot help but try and interpret such phenomena along realistic lines, sometimes in a very naive way, as if “something,” some kind of mind-stuff, was wandering around in the emergency room floating above the body. In other words, it is difficult when sensory experiences are at play not to take the patients’ reports literally.
He replied,
Sometimes, when you talk to many near-death experiencers who assume they left their bodies and therefore their brains behind, you start wondering where we ever got this crazy idea that brains were involved in thinking. Where did this idea come from? Obviously it comes from our everyday lives. In our everyday lives, it seems as if the mind and the brain are the same thing. When you get knocked on the head, you don't think very clearly. When you get drunk, you don't think very clearly. It seems very obvious that the state of our brains affects the state of our thinking, our emotions, our thoughts, our feelings, our desires. And that seems to hold true for much of our daily lives. It doesn't seem to hold true in the extremes. Let me give you an analogy.

This morning Henry Stapp talked about Newtonian mechanics, which was accepted for 300 or 400 hundred years as a description of this wonderful clockwork world we live in, which was perfectly acceptable. Newtonian Mechanics treated the world as if it were billiard balls, which works very well for most of our daily lives. When you throw something up, it falls down, all the time. The harder you throw it, the faster it goes. Newtonian Mechanics works fine for everyday life. It is only when you get to the extremes of measuring extremely small particles, or extremely fast speeds, that the Newtonian model breaks down. It's not that Newton was wrong; it's just that the formulas he was using are a limited case. When you get to the extreme examples, his formulas no longer work and you need relativity to make the corrections.

In normal everyday life, the corrections relativity adds don't make much of a difference, and Newtonian formulas are a good approximation. I think the same thing is going on between the brain and the mind. In our everyday life, assuming the brain and the mind are the same thing works perfectly fine. It's only when you get to the extreme cases, such as when the brain stops functioning, that you see the analogy breaking down, and brain and mind don't seem to be the same thing. The most common example that's talked about now is the near-death experience. We have people who seem to be clinically dead, a few people who have actually had flat brain waves documented, who come back saying not only was I thinking, but I was thinking more clearly than I ever had before. But we also have other examples of cases in which the brain is compromised and yet people think more clearly. There are exceptional cases of people who have irreversible dementia or severe mental illness, who in their dying moments before they die become perfectly lucid: they start recognizing family members, they start talking coherently, they lose their delusions. And then they die.
It's quite possible that one of the brain's actual purposes is to restrict thinking - to narrow it to channels suited to the reality in which we live.

If we were conscious of everything going on around and within us, and fully realized the significance of all that we actually know, who could handle it? We would go mad and jump out of windows. We don't, because our brains restrict us to thinking about the deadline we must meet this afternoon, what's on the menu tonight, and whether we remembered to lock the back door. In other words, the stuff that keeps us on track in our ordinary lives. Only at the margins does that stream of everyday consciousness dissolve in favour of a larger one.

That may help us understand why many people change their priorities following a near death experience. Anyone can repeat the ironic mantra "No one ever said, on their deathbed, I wish I had spent more time complaining." We go on spending too much time complaining.

But suppose a person has a near-death experience in which she experiences a higher level of consciousness. So she changes. But what changed? Her normal stream of consciousness was interrupted, and she saw what that stream had prevented her from seeing clearly: She is the only person who is stopping her from living n the way that she thinks is right.

That might be a model for understanding serious life change in older people. However. Greyson also offered a caution about models:
William James was living in the steam era and he used the reducing valve, a model from the steam engine. And people since then have used the television analogy that the brain is like a receiver for the television signals—we keep changing our models. Now, the mind is software and the brain is hardware. The point is that the brain is not producing thought, it’s receiving thought or limiting thought in some way. And in that model, the brain is the way in which the mind has a function in the normal world. I’m not going to embrace any of these things because I think they’re all so locked into very limited models.

Let me connect with something that was mentioned this morning, and that’s the role of language in all this. If you ask near-death experiencers to describe what happened, they will usually start off by saying, “I can’t, it was ineffable, there are no words to describe what I went through.” And then we say, “Great, tell me about it,” and we force them to use words. And then we write down what they said as if that were the truth. But the fact that we make them use words doesn’t mean the words were accurate. And in fact, if you look at cross-cultural comparisons, there’s a core near-death experience that is the same all over the world. But you don’t have the same vocabulary described all over the world. Here people talk about tunnels; people in third-world countries don’t talk about tunnels, they may talk about a cave or a well, or one person told me about going through the stem of a flower. I had one truck driver who told me about going through a tail pipe. So your cultural background determines what words you use. People who come from a culture where you have a belief in a god will talk about seeing God. People from cultures where there isn’t a god, such as the Buddhist cultures, don’t talk about seeing God in their near-death experiences. They may talk about seeing deceased relatives, they talk about a warm, loving sense of whatever it is. When the Star Wars movies came out, a lot of near-death experiencers said, “Yes, the Force, that’s it, it’s the Force.”

I think it goes deeper than just our language. There’s a problem in how the culture makes us think that distorts how we describe things. As Sam mentioned this morning, so much of the way we think about things came from the ancient Greeks, and in fact our system of logic, of how we deal with ideas, is determined by Aristotle’s, it’s called a two-fold system of logic, where things are either true or false. He postulated the law of the excluded middle. Things can’t be both true and false, they have to be true or false. And that type of logic leads us to have what we’ve called “mysteries,” things we can’t explain, so we can choose between trying to reduce them to things we can explain, or to saying it’s a mystery that we can’t solve. That’s because we are locked into this yes-or-no law of the excluded middle. Other cultures don’t have this. There is a Hindu system of logic that was developed by Nagarjuna, in which there are four different types of logical statements: things can be true, or they can be false, or they can be true and false, or they can be neither true nor false. And all those are logical statements in their system. And when you think about what physics is doing these days—remember what Henry was talking about this morning—we have things that don’t fit into our logic. So philosophers can say, “Well, quantum physics is illogical.” Maybe it is by our Aristotelian logic, but not necessarily by another type of logic. Is a photon a wave or a particle? According to Aristotle, it has to be one or the other; it can’t be both. But in other forms of logic, it can be both or it can be neither. So maybe what science has to do, what scientists have to do, is get beyond our own prejudices and start using not only other languages, but other ways of evaluating the language, other ways of thinking.
Next: Mind-body panel 2: Christina Puchalski - "We know maybe forty percent"


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