The Intuition Network, A Thinking Allowed Television Underwriter, presents the following transcript from the series Thinking Allowed, Conversations On the Leading Edge of Knowledge and Discovery, with Dr. Jeffrey Mishlove.


JEFFREY MISHLOVE, Ph.D.: Hello and welcome. I'm Jeffrey Mishlove. Our topic today is "The Scientific Search for the Soul." With me is one of the great scientific minds of the twentieth century, Dr. Francis Crick, who received the Nobel Prize in 1962 for his discovery of DNA. Dr. Crick is the author of Life Itself, What Mad Pursuit?, and The Astonishing Hypothesis. He is a faculty member of the Salk Institute in San Diego, California. Welcome, Francis.

FRANCIS CRICK, Ph.D.: Well, thank you for asking me.

MISHLOVE: It's a pleasure to be with you. I'm sure members of our audience would be very interested in knowing how you began to develop an interest in solving the mystery of human consciousness, after you'd already made quite a reputation for yourself as probably the individual who would be credited for solving the mystery of life.

CRICK: Well, my interest goes back a long way. During the war I worked for the British Admiralty, the Second World War, and after that I had to decide what field I would go into. And that wasn't easy, because by that time I was about 30, and I hadn't got much of a scientific background. I had a degree, of course. So I had a fairly free choice, and like the kids in the sixties, that sometimes makes a problem, if you have too many things to choose from. So I took some time trying to work out what I was really interested in, and I invented what I called the gossip test: What you're really interested in is what you gossip about. Gossip is things you're interested, but you don't know much about. And I was talking to naval officers, and I found I was telling them about penicillin. Well, I didn't really know much about penicillin. And so I used this gossip test, and I found what really interested me were two regions -- the borderline between the living and the non-living, what we nowadays call molecular biology; and the brain and the problem of consciousness. Well, then I had to decide between them, and after much thinking I decided that I perhaps knew a little bit more about things like molecular biology, so that's how I became a molecular biologist. But I always had this long-term interest in the other problem, and when in 1976 I went to the Salk Institute, I decided it was now or never, so I decided to change over and become interested in the brain.

MISHLOVE: Well, I suppose it's fair to say that very few scientists can say that they've been able to devote large portions of their career to these two most fundamental of problems.

CRICK: That's probably true. I think of course what happens usually with young scientists is they get into something which they're sort of somewhat interested in, and then they start doing research, which often is on the advice of their professor, and by the time they're 30 they're sort of trapped in their expertise, and it's not easy to make a change. I made the change because I thought, when I'd reached that age, which was 60, I was entitled to do what I wanted, and that's what I felt I was most interested in.

MISHLOVE: When you began to work on DNA, it was at a time, I think, when most people in the field of molecular biology -- or biology; there wasn't much of a discipline of molecular biology then, I suppose -- would have been astonished at the idea that a single molecule like that would be found to be so fundamental to life and reproduction.

CRICK: I think there were people going back to the twenties. Muller used to give lectures on the chemical nature of the gene. What we were interested in is what is the chemical nature of the gene. Not so many people, when we started, would think it was DNA; they thought it would be proteins that were involved. And nobody, not even us, thought the structure was going to be such a giveaway -- that looking at the structure you could deduce how it might replicate and what it did.

MISHLOVE: The double helix.

CRICK: Yes -- well, the fact that the bases pair, essentially.

MISHLOVE: But now you've moved into the field of human consciousness, and in your book The Astonishing Hypothesis you maintain that the astonishing hypothesis is fundamentally that the neuron is the basis of consciousness, just as DNA would be seen as the basis of life.

CRICK: It's the basis, but remember it isn't just a single neuron. It's the interaction between the billions of neurons we have in our heads, or possibly, probably in animals' heads as well, which is producing the process, because consciousness is a process, not a thing, and the neurons are the actors.

MISHLOVE: There are of course many people who are now coming into the arena of the science of consciousness with theories ranging from computer models to quantum physics. Let's focus in a little bit more on the neuron. It seems to me that the fundamental philosophical question would be: even if we talk about billions of neurons, or many neurons, interacting together, how is some kind of a physical system like that going to generate my experience of you sitting across from me at this moment?

CRICK: Well, your experience of me has a number of different aspects. One is that you're taking in information from your eyes and your ears and so on, taking in a lot of information, so that your brain is really a machine which is processing information. So it isn't too surprising that neurons can do that. After all, chips in computers process information. There is a much more difficult problem, of what philosophers call qualia -- the redness of red, and the painfulness of pain. But I think one should regard these as two aspects of the problem we're trying to solve.

MISHLOVE: Right. In other words, on the one hand, if I were a computer I might be able to register that there's another machine in front of me, without actually seeing, the way a human being sees.

CRICK: Well, that's true, but I wanted to say that the actual mechanisms, which are probably not the ones we have in computers, because there's a lot going on at once, and you unify it in some sort of way -- that's probably what makes you conscious. But if you want to convey to me what red looks to you, you've got to translate that into several stages -- into language, and then into movement, even if you just point. And you've got to recode it, and that recoding is a personal property, probably, and therefore you can't convey to me the exact redness of red, and therefore it's difficult to do scientific work on that aspect of it. But to know which part of your brain is signaling which is red, and what makes you aware of what is red -- because you can have the what you might call red neurons going on in your brain even when you're in a deep sleep, you see. It's not just because there's some activity; there has to be some special activity, and that's what we want to find out.

MISHLOVE: You seem to be saying that when it comes to my experience, there's going to be a level which is so unique to me that it's beyond the scope of science, but that science can still explore quite a bit about human consciousness and experience.

CRICK: Yes, but it's very rash to say that things are beyond the scope of science, because it could be argued that in some period, along sometime in the future, it will be possible to connect in some fine detail your brain to my brain, so that I could experience the way you were seeing red. Now nobody knows what we need to do to do that; we know virtually certainly we can't see how to do it at the moment, and maybe it will always be impossible. But it would be rash to say it could never be done.

MISHLOVE: It's certainly an idea that's been in science fiction for a long time.

CRICK: That's right. But they always think it's just easy. You just take a few wires and plug it in. It's certainly going to be more difficult than that.

MISHLOVE: Well, perhaps I might ask you bluntly, what is your assessment of the state of neuroscience at this point in time?

CRICK: Well, I think one has to say two things. Neuroscience has developed remarkably in the last 10 or 20 years. You can see this for no other reason than the increase in the numbers of neuroscientists. When they have their annual meeting, I think the last meeting there were 23,000 of them, something like that. When they started it was only 1000. So the large increase in people working on it. There's a very considerable increase in our knowledge, which is why we can start thinking about experiments and ideas. But when you look how far you've got to go to explain this very complicated thing which is our brain, and all the processes which are very transient and interacting in very intricate ways, we're clearly only just beginning. But nevertheless, we have made a solid beginning, but only a beginning.

MISHLOVE: You seem to like the idea of reverberating neural circuits as a basis for mental experience, for mental images or consciousness.

CRICK: Well, that's not, of course, my idea. It's the Canadian psychologist Hebb who put it forward, and others may have done it before.

MISHLOVE: Donald Hebb.

CRICK: Yes. We think we should look out for that. We don't necessarily believe it has to be that form, and it's not at all clear which circuits would reverberate, because things are so interconnected in the brain that to get a reverberation which doesn't spread all over the place is not easy. And if you do get a reverberation which spreads all over the place, you have epilepsy, you see. So it's one of our speculative ideas, but not something which we feel deeply about, shall we say.

MISHLOVE: OK, but when we talk about visual processing in particular, which is an area that you've specialized in, you seem to favor the idea of a reverberating circuit between the cortex on the surface of the brain and a deeper area called the thalamus.

CRICK: Yes, that's perfectly true, but what we want to explain is the fact that you have to have some form of very short-term memory. If you couldn't remember at all what had immediately happened, it's difficult to see how you could be aware of anything. So there has to be some form of very short-term memory, but it could take other forms. That's just one of the possibilities, and it's certainly most unclear which circuit. We suggest that circuit for certain technical reasons, but most of the experiments that have been done on this have been done on the animals under an anesthetic. So it isn't too surprising we haven't seen the actual reverberation.

MISHLOVE: I notice that when you answer my questions, as you wrote in your book The Astonishing Hypothesis_ every answer needs to be qualified. The field of neuroscience is so complex that it seems as if there is no way to state a simple and obvious theory about any of it.

CRICK: Well, say it would be if you talked about genes, if you talked about genes and what they are. In fact if you ask anybody in the field to define a gene, they have great difficulty finding a definition. And that's because basically we believe it's all evolved by natural selection, and it's a lot of molecular gadgetry and so on, and you don't expect it to be a simple, crisp answer as you get, say, in the Newtonian mechanics. Biology is very different from physics in that respect, at least from fundamental physics.

MISHLOVE: Well, I'm puzzled a little bit, because since the field is so complex and amorphous and ambiguous, and no one theory seems to exist without many objections popping up along the way, why do you hold that neurons are so primary?

CRICK: Well, it's difficult to see unless you want to go to something which is immaterial; it's difficult to see. And we wouldn't want to say that certain of the molecules associated with neurons, or even what's called the glial cells -- the point about neurons is that they're very good at sending information over long distances or you couldn't waggle your toes, for example. That's why we concentrate on neurons. It's just a natural place to focus, but it doesn't mean to say we don't look at groups of neurons, and we also look at the components of neurons and the things affiliated with neurons. It's just to focus attention.

MISHLOVE: One of the big philosophical arguments in the field of consciousness is the mind-brain problem, and you're suggesting that if we look at neurons, that will be the way to resolve that problem. Another major philosophical controversy is then the question of free will, and you seem to have a unique approach to that question as well.

CRICK: Well, I'm not sure it's unique. There is a postscript to the book, which is written in a rather lighthearted manner, because a friend of mine, a scientist in South America, wrote to me about free will, and I could see that his ideas were very different from mine. I didn't know I had any ideas about free will. So I then wrote them down, what they were, in a sketch way. But the point of that postscript really is to say -- it does suggest a sketch of an idea about free will. But the real point of that is to say that any explanation probably depends on the distinction between the conscious processes in your brain and the unconscious ones, and it would be wise to understand that first before you got too deeply into free will. I mean, you must have noticed that, for example, among your friends, that they sometimes don't always give the reasons for what they're doing, that they think it is quite genuinely. And you can sometimes predict what they're going to do before they actually do it, you see. So you have to incorporate all that, and that's because what comes out as free will has got a lot of unconscious processing going on before that, and if you don't know how to make that distinction it probably won't be easy to explore free will scientifically.

MISHLOVE: Then you suggest that we have perhaps a part of our brain which might be the seat of where we make decisions, that at least seem to us decisions based on our free will.

CRICK: Well, yes. Of course one mustn't oversimplify. It isn't possibly one single part; it will be probably a number of parts interacting together. But a key part is somewhere about here, and if people have damage to that -- it usually has to be partly on both sides, because you in general only have one free will because of the connections between the two parts of your brain -- you can have damage such that if some object like that, or perhaps a glass of water, were put there, the person with damage, say, here, the hand will reach out and grasp the water, a simple, automatic sort of action, and the person will say, "I didn't will that." And sometimes they can't get their hand to let go, and this hand has to do it. One man found he'd get his hand to let go by saying, "Let go" in a loud voice; it would let go, you see. So you can have limited but restricted behavior which you deny you willed, you see. So since the damage is there, we think that must be part of the system involved. It's very unlikely to be at the back. The back is of course mainly visual, and the cerebellum at the back of that.

MISHLOVE: It seems, too, in your discussion of free will, that you suggest that part of the brain is responsible for planning and developing strategies, which at some point along the way become incorporated into decisions. And if our behavior is based on plans that we have made, you could view that in a way which doesn't necessarily defy scientific restrictions against what is called teleology, or free will, in science. Am I understanding you correctly?

CRICK: Well, we don't understand these parts of the brain very well. They're the least understood parts. We do know that probably when you're planning things, you do it at different levels. You make long-term planning things about your career. You make plannings about when you're going, say, on vacation; that's a shorter time period. You make plans what you're going to do when come in the morning, and then of course actually to the stage where you're going to plan, "Touch that," and so on. So there's probably a whole series of these things involved. And it's also true, of course, that you do plan. You don't just act spontaneously, if you're wise, everything that comes on into your head. The real problem is, how is that all organized on a neural basis? And that is probably one of the least understood parts of the brain.

MISHLOVE: I'd like to ask you another question about something that is surely least understood, but you did say earlier that you began exploring the questions of life and death, and of course you're a pioneer in our understanding of life. But I wonder if your explorations have given you any insight into the nature of death itself, either biologically or neurologically.

CRICK: I don't think any special one. I mean, obviously if you believe in the astonishing hypothesis, namely, that it's all due to neurons, if your brain dies, essentially you as a person would be considered dead, whereas the more conventional, and often the religious, interpretation is that in some sense some immaterial spirit survives. But beyond that I don't think I have anything special to say.

MISHLOVE: One of the things you have written about is that the conventional religious views of looking at consciousness have generally not held up over time, and in your view are not likely to be fruitful in future explorations.

CRICK: Well, I would perhaps put it a slightly different way. I would say the religious views historically, about different aspects of science, not consciousness -- like the size of the earth, or the age of the universe, and so -- many religions thought, and some still do think, that they have answers to that. And those are the ones that haven't stood up. But when we come to consciousness, science hasn't developed far enough for us to say whether it's stood up or not. And that's why it's called an astonishing hypothesis, because it's a working hypothesis that it's not the same as the conventional religious views. So we have to wait and see. After all, it may turn out that they're right in their views. We can't say that yet.

MISHLOVE: Actually, it's interesting that you would even call it a hypothesis. Many people, I suppose, in the field of neuroscience consider it a given.

CRICK: Many people do. Many medical people do. A lot of scientists do. And quite a lot of people who aren't scientists also feel it isn't astonishing, including my editor, incidentally, who said it wasn't astonishing. But what such people don't realize, if they talk around to other people in this city or anwhere else, it's often surprising how you find a different view. It just doesn't always come up. Most politicians, at least nominally, for example, don't agree with it. They're mostly Christians, and the Christian faith says yes, your soul survives after death -- just to give you one example. But there's another facet to this. Many neuroscientists and people in general say, "Yes, of course, I do believe that it's all in my head." But they haven't seen the implications of that. They haven't seen the way you have to think about it when you adopt this point of view, because it isn't straightforward at all. And most people manage to think in two modes. They impose the idea that there's a little person there on the activity of the neurons, and of course that sort of mixed theory, which is what most of us do most of the time --

MISHLOVE: It's called the ghost in the machine, or the homunculus.

CRICK: That's right, that's right. Most of us act as if there's a ghost in the machine, because it's the best way which we can approach the problems of everyday life.

MISHLOVE: Well, how do you feel when you wake up in the morning, yourself, and you think --

CRICK: I think I feel just like you, Jeffrey. I don't think it's very different, I mean. Of course, as you may notice, people now do realize that taking various chemicals -- the one most often mentioned to me now is Prozac, but of course there was Valium and all those things -- will alter your mood behavior; in other words, the way you process the information. It doesn't necessarily make you hallucinogenic, which would be a change in the information, but it does alter the mood in which you do it. And to some people that has been a surprising idea. They feel that isn't it remarkable that their character is changed by chemistry. They've forgotten about alcohol, of course, which has been known for several thousand years, that that has an effect on character.

MISHLOVE: We have long known that drugs affect the mind. That's probably one of the earliest discoveries of our species.

CRICK: But it's very peculiar that people who worry about Prozac don't think about alcohol as a precedent. Of course there are are differences.

MISHLOVE: Indeed. Yes. Well, let me just jump around another moment with you, because I'd like to hear your comments about cognitive science from the point of view of artificial intelligence, and people who say, "Well, we will soon have computers that will be conscious as humans."

CRICK: Well, I think that's difficult to answer. Personally -- I mean, it's just conceivable -- we have computers now, and we'll be able to look back and say in a very weak and feeble way they have something which we might describe as consciousness. I don't think they feel pain, for example. But that may be the case. But until we know what it is we're talking about -- remember, the ideas in this field are being developed, and the reason we need to do more experiments is to check our ideas and to improve our ideas. When we have a clear idea of what we mean, what we're talking about, and what's going on in our heads, then we can ask, are there analogous operations, not only in computers, but we have the problem as you go down on the biological scale. We think most mammals are, and so on, but what happens when you get to a fruit fly, or an ant, or something like that? We all have these problems, and I don't believe they'll be answered until we really understand the problem better.

MISHLOVE: One of the things you did write about were what are now known as neural networks -- certain types of computer programs that are designed to simulate the interactions of neurons. And some of them, as I understand it, have shown a remarkable ability to learn and integrate data in ways that even the designers of these networks don't understand.

CRICK: Well, they understand them, but they've been surprised, I think, at the results. The basic difference is, when you take a computer, broadly speaking, you have to put in a program. You have to think in advance. You know -- if this, then that. You have to work out -- suppose you're doing medical diagnosis. If they've got spots here, and they've got a temperature, and so on, then that. And that all has to be precoded. Now of course that's not the way, for example, that children learn a language. They learn the rules of grammar, but they don't know what the rules are. They have tacit knowledge of it. These neural networks, which work in parallel, aren't programmed. They have rules for learning, and the learning rules allow them to grasp; they have tacit knowledge of the rules in the way they alter their connections. So they are more brain-like, but one has to say that they're still extremely simple. They don't at the moment have attentional mechanisms, which you mentioned earlier, and so on. And the neurons, the individual units, are simple caricatures of individual neurons. So people are now trying to make improved neural networks, to think about the theory of them, to understand more about neurons and put more complicated ones into networks. But it's got a very long way to go; but it has got off to a good start.

MISHLOVE: One of the comparisons that you've drawn between the computer and the human brain is that neurons operate much more slowly than computer circuits do, but there are billions of them operating in parallel.

CRICK: Absolutely. That's right. Clearly it pays an animal to be able to react pretty promptly, or it's going to be eaten, or won't be able to get its dinner. There's a lot of reasons. And we start with these relatively slow components. They only work in the time scale of a thousandth of a second, whereas the chips in the computer go almost 100,000 or a million times faster. And the trick, as you say, is to make them work in parallel, so that when you have a TV screen, for example, a TV camera, you scan the image, and you send out the picture as a series of scan things, and then you scan it again. But when you have something coming from your eye, there are a million nerve fibers going from one eye to the brain, and if they're active they all send their information in parallel. So that probably puts it in a very concrete way, the difference.

MISHLOVE: Yes. Dr. Crick, we're just about out of time. It's been such a delight exploring with you these issues of consciousness and science. I think it's striking that you're willing to treat consciousness in sort of a matter-of-fact way, whereas other scientists are kind of afraid of it.

CRICK: Well, of course one of the reasons for writing the book was to try to get them to think about it my way, not their way.

MISHLOVE: Thank you so much for being with me. It's been a pleasure.

CRICK: I've enjoyed it. Thank you, Jeffrey.

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