|ROGER PENROSE & TED HONDERICH ON THE
SUBJECT OF CONSCIOUSNESS
BBC IN OUR TIME PROGRAMME
CHAIRMAN MELVYN BRAGG
Melvyn Bragg : Well, we could have had a better start than hearing about England cricket to tell you the truth! Anyway.....erm one of the greatest mysteries facing science and philosophy today is the problem of consciousness. Can we explain our perception of colour, smell or what it's like to be in love, in purely physical terms? Can memory , conviction and reason, be explained primarily in terms of neural firing sequences in the brain? Three centuries ago, Descartes famously believed that the problem was best solved by being ignored, was he right? Could it be that that the human mind is just not built to understand its own basis?
With me to try to unravel the complexities of consciousness are the philosopher, Ted Honderich , recently retired from his post as Grote Professor Emeritus of the Philosophy of Mind and Logic at University College, London, and the eminent physicist and mathematician, Sir Roger Penrose, author of, amongst many other books, "The Large, The Small and the Human Mind", he's the former Rouse-Ball Professor of Mathematics at Oxford.
Is it possible, elliptically, or briefly, to say, what consciousness is, Roger Penrose?
Roger Penrose : Well, that's a difficult question (Mel laughs), but I mean, by consciousness I would tend to mean, basically awareness, er...but also...that's the sort of passive aspect of consciousness, but also freewill, whatever these things mean, I would say, is included in, sort of, the active aspect of consciousness. But basically being aware, it's hard to define, because I don't think we really know what it is yet.
Melvyn Bragg : Ted Honderich?
Ted Honderich : I think consciousness is at bottom, something you can call perceptual consciousness, that is, being aware of the room you are in, or perhaps aware of the car you are driving, and if one asks the question, "what is it it be aware of one's surroundings, what is it to be perceptually conscious?", I think the proper answer is essentially this, it's for a world, in a way, to exist. That answer isn't this one, that the world exists and you're somehow you are aware of it, Rather, the claim is that what it is to be aware of a world is for the world to exist. That's my own view, and not popular, but it might be true, anyway.
Melvyn Bragg : Roger Penrose, why does this consciousness.....why is it so fascinating for both philosophers and scientists?
Roger Penrose : I think it's something that people have been of course, interested in since we begin to think about things at all, but I think the main question is why scientists have become interested in this......
Melvyn Bragg : Indeed.
Roger Penrose : ...... and I think it is a bit of a new phenomenon that scientists have taken this subject seriously. I think it's partly a matter of being able, much more accurately, to tell where different things are happening in the brain, are these techniques like PET scans, and so on, which can pinpoint thoughts and things of that sort. It doesn't tell us much more, because to know where something is happening, doesn't really tell us what's going on, which makes the phenomenon of being aware...... what is it that does that? Errr......
Melvyn Bragg : What sort of pinpointing, to be more specific for our listeners, what sort of pinpointing would you give as an example of .......
Roger Penrose : Well....
Melvyn Bragg : ....scientists developing in this area, and therefore thinking they can have an interest in this area?
Roger Penrose : Well, there are certain very clear cut things like perception of motion or perception of colour, which are in quite two.......two quite different parts of the brain. I mean this is one of the big puzzles that neurophysiologists have about understanding how it is we form a mental image of something, because the different ingredients to that mental image are involved.....different parts of the brain are involved, and they can be quite different, you know quite widely separated regions in the brain, but yet one doesn't have this somehow image of different things, separate. So there's this problem of how we find...form one image. But the fact that these different aspects of an image, in a sense, registered in different parts of the brain, is something that's known now, from these kinds of scans that can be done.
Melvyn Bragg : Ted Honderich.
Ted Honderich : Could I promote a certain distinction which I think is very necessary here? There's the question of what consciousness is, first of all, and it's the one we began with, and gave our initial answers to, and there's the question of what the basis or explanation or cause of consciousness is, and that second question is, of course, a separate one. Now many people believe that the basis or cause or explanation of consciousness is in the brain, and indeed in particular parts of it, which are well studied. I wasn't quite clear whether Roger Penrose had the view that, not only the basis or cause of consciousness is in the brain, but also had the view, perhaps slightly more remarkable, that consciousness itself is that stuff in the brain. That is essentially electrochemical activity. That second view is perhaps less attractive than the first, sometimes called "eliminative materialism", and usually held in...
Melvyn Bragg : You're going a bit too fast for us, you really are...
Ted Honderich : ....places of strong sunlight......
Melvyn Bragg : ....you really are going a bit too fast for us. You've got to take.....this one step....well, I've got to take this one stage at a time, you maybe have brilliant listeners out there, but....just one point at a time. Do you want to reply to the first part of that, Roger?
Roger Penrose : Well let me say, I don't think it's electrochemical processes in the brain, let me just...(laughs), I mean I can say a bit more what I do think it is, but that's certainly not my view. I think we're a long way to go before we know what's going on. So I think there's something quite different from ordinary physical processes involved.
Melvyn Bragg : Can I go back for one moment? Can you tell us about the theories of functionalism which were one way to understand the modern understanding of consciousness, as I understand it, following on from Gilbert Riles book in the middle of the century...middle of this century, the concept of the mind, initiated behaviourism and then functionalism, which became an idea a way of looking at it? If you could tell us what that was and where it got to.
Ted Honderich : I take it that functionalism might be thought to have its origin in certain truisms. If you tried to explain say what a desire was, a desire in general, it would be impossible to leave out that desires were owed.....are owed to or spring from perceptions or input and they give rise to behaviour or output. The desire for a glass of wine, is very typically the effect of seeing the man with a tray of glasses, and it's the cause of one's arm going out to grasp a glass. So an adequate conception of a desire would include the input and the output. Functionalism takes the radical step of saying that the desire is no more than whatever is in those causal or possibly logical relations.
It's just the state, that is the effect of certain input and the cause of certain output.
Melvyn Bragg : So love is a series of bodily movements for instance?
Ted Honderich : Well functionalism is yet more, so to speak, elusive than that, because what makes the thing a desire, is that it's in those relationships, it needn't be neurochemical, it needn't be silicon and it needn't be anything. Whatever is in those relationships, that is whatever "functions" in this way, is a certain kind of effect and a certain kind of cause, is a desire, and more generally conscious states are things that stand in these causal or indeed logical or computational relations. That roughly is functionalism.
Melvyn Bragg : Roger Penrose, of course you're a physicist and you're coming at consciousness from that point of view, but you've so far...you've been, as you've said publically, well in your books, you've been disappointed because you've spoken of a "missing physics". You've said that physics can deal marvellously with the big problems, Newtonian physics, the tiny tiny problems from quantum physics, but there's a missing physics. First of all, what's that? And secondly, why should that have the answer?
Roger Penrose : Well I think there are two separate issues here. One is...has nothing to do with the mind, or at least it doesn't have to have. Namely that there is something missing, fundamentally missing in our physical picture of the world. Now this just comes from physics, and that the thing I regard as "missing", is the sort of bridge between the quantum level, which describes how atoms, fundamental particles molecules behave, and the large scale classical level, which describe how cricket balls behave, and there is a sort of stop gap way in which this is treated at the moment, but I think this is just a fudge and that we are going to have to have some new physics which bridges that gap, and I just think it's missing. Now whether that has anything to do with consciousness, of course is a separate issue, and I think my main reasons for believing it has something to do with consciousness , or that consciousness depends upon it, put it like that, I don't think it answers the question of what consciousness is. But I think consciousness depends upon this missing ingredient, and the reasons come partly from the belief that the two levels of physics that we do understand, the quantum and classical levels are basically computational , so they're things that we could simulate on a computer as we understand computers today, and I have strong reasons to believe that our conscious thinking is not something of that character. So if we believe it's physical, we have to look to something which is not in our present physical world view, and the most likely place, is this gap between the small and large scales.
Melvyn Bragg : And you've talked about micro tubules being a possible key to understanding.
Roger Penrose : Yes and again it's a somewhat negative argument in the sense that I don't see any role for this gap being sort of relevant in ordinary nerve signal propagation. You have to look down more deeply into smaller structures, more organised structures, things of a more crystal like nature, which could possibly support the quantum level, and you need to go both sides if you like. You need something which could support quantum level activity and something classical, so that you can make use of the bridge between the two. But it is a somewhat negative argument.
Melvyn Bragg : Yeah. Ted Honderich, what do you think of this argument?
Ted Honderich : Well, I'm afraid Melvyn, possibly to your irritation, I would like to go back to the two questions.....
Melvyn Bragg : No, No I wasn't irritated.......
Ted Honderich : ...which I wanted to separate.
Melvyn Bragg : ....I was just trying to sort of get a cleaner line. It was.....
Ted Honderich : And the....and the two questions are, what is consciousness, and secondly, what is it's cause or basis, and they are distinct. Now it's very unclear to me, whether Roger thinks consciousness is micro tubules or micro tubular activity......
Roger Penrose : I said.....no....
Ted Honderich : ...that is neurophysiological activity of some sort, or whether he thinks that that neurophysiological activity is the basis or ground or cause of consciousness. Now, if he thinks the second thing, that is a fairly conventional view. A version of the though that consciousness is somehow based in the brain, but doesn't give us any answer to the first and fundamental question, what consciousness really is.
Roger Penrose : Can I perhaps comment? Because I think the important thing is we need to know more about what the world is like. I mean when you ask questions like what consciousness is, we don't even know what an electron is. I mean until we know better what the physical world is like, we're not going to know how we can fit the phenomenon of consciousness in together with that physical picture. So I think... I think.... I have a feeling you're looking at this rather, in , if you like, and old-fashioned way, in which physics is viewed, we're going to have to know more about the physical world before we can attempt seriously to answer this kind of question.
Ted Honderich : But still, could I ask the question, once more? You mentioned micro tubules, which are...they are a neurochemical fact. Do you take consciousness to consist in them, or to be based on them?
Roger Penrose : No the micro tubules are just a vehicle, I mean they're not the important phenomenon. The important thing is to tap into something in the physical world which is much deeper than those things we know about the physical world already. We have some feeling about the quantum level of the world. We have some feeling about the classical level of the world. We have almost none about the bridge between the two, and I believe you need to tap into that bridge in order to sort of manifest consciousness.
Melvyn Bragg : Can I ask you, Roger, you've always claimed that consciousness can't be simulated on by computers, given apparent advances in artificial intelligence. Why do you feel so strongly about that?
Roger Penrose : Well....
Melvyn Bragg : What's your evidence?
Roger Penrose : ....(laughs)...
Melvyn Bragg : (coughs) Excuse me. What's your evidence?
Roger Penrose : I think there's more than one piece of evidence there. I mean computers certainly do wonderful things, and of course one famous example is Deep Blue and its Chess match against Gary Kasparov, where it did win the match, lucky it might have been, but it did win the match. However, there are Chess positions that you can give to Deep Blue and it simply makes completely stupid moves, and you can understand why it makes those stupid moves, and you can understand what the right moves are, and the reason is it has no understanding. Now I would say, that the word "understanding" more or less characterises what I regard the things that computers can't do. They don't have any understanding. You can see why they do well in the tasks that they do well. It's human understanding that is being, you know applied again and again and again, but there's no understanding that the computer has.
Melvyn Bragg : So therefore the computer model doesn't take you very far. You use the example of children's grasp of natural numbers here don't you?
Roger Penrose : That's.....yes, I think that's rather a good example. The trouble with Chess is that it's a finite game, and you could ultimately design a computer which by brute force computation could do as well as you like, in principle, I mean it's beyond present day capabilities. But, in mathematics, and the natural numbers, 0, 1, 2, 3, 4 is an infinite family, and there is no way to encapsulate all the properties of the natural numbers simply in terms of rules, or mechanical procedures , and that I think, reveals the phenomenon of understanding more clearly than something like a finite game like Chess.
Melvyn Bragg : Does that help in the search for consciousness Ted Honderich?
Ted Honderich : I 'm afraid it darkens the scene, absolutely in several ways. Roger Penrose has an idea.....
Roger Penrose : (indistinct) (laughs)
Ted Honderich : .......has an idea that somehow understanding or insight is going to be particularly enlightening with respect to the subject of consciousness, and I fail to see that. If one thinks about organisms from the amoeba up, at some point consciousness becomes a fact of such a an organism, a very low grade organism, but it is conscious. It's a long way off the understanding or insight or whatever which Roger Penrose associates with consciousness, that's one point. I have another, but maybe I'll wait for that one.
Roger Penrose : Can I address that one?
Melvyn Bragg : Address that one first.
Roger Penrose : Well...
Melvyn Bragg : One at a time it's easier.....
Roger Penrose : (laughs)
Melvyn Bragg : In this sort of linear discussion, it does work better, yes if you answer that!
Roger Penrose : Yes, I think there's a misunderstanding here . I'm not saying that this is the only manifestation of consciousness, I mean the perception of the colour red is a manifestation of consciousness. There are all sorts of things which.....where consciousness is involved. I'm just not talking about those particular things, and if I want to show that something lies outside computation, then if I can show it in one example, then that's sufficient, that means that you can't do it with computation. Now I'm not...... I just think that you can't make a computational device perceive red either, but that's not something where I can apply mathematical arguments. So I'm certainly not saying this is the characteristic of consciousness, that consciousness is only understanding. There are many other aspects of consciousness, certainly. But it's the only one I can get a handle on, and to show that it is clearly, from mathematical argument, something outside a purely computational activity.
Ted Honderich : Well.....
Melvyn Bragg : Can you take us to your next question?
Ted Honderich : ...I remain baffled about what Roger Penrose thinks consciousness is, but let me say just something about computation and computers. Certainly it's the case that present computers only compute. But I think Roger Penrose also holds the view that mechanical devices or artefacts couldn't do this shishi (??) thing, that is understanding or insight. It's not at all obvious that you shouldn't have a mechanical device which did that, non-computationally, and indeed, I think he actually allows that in his book , rather late on. In which case, I'm not quite sure why he's so condescending about the poor computer.
Roger Penrose : The....the....to have a device which behaves non-computationally, would have to...we'd have to build it out of something we don't know about how to do at the moment. Ordinary.....I mean that's part of my argument. If you used simply classical physics, some use cogs, balls running around things like that, that wouldn't do it. If you used purely quantum end of things, that wouldn't do it either. So this is the reason I say you need something beyond the present physical picture.
Melvyn Bragg : Can I just go back a little bit, in order to go forward? There have been lots of people writing....we've mentioned Descartes, far too briefly. Hobbe's idea that there was no fundamental difference between our minds and our bodies, is that a view which has any sort of currency at all today still, Ted Honderich ?
Ted Honderich : Well it does have currency in Southern California and Australia, those places have strong sunlight, which may affect philosophical reflection! That is there is the view that the mind is nothing but the brain, where that means that consciousness consists of nothing but electrochemical activity. But it's very much a minority view. Functionalism, the view that you mentioned earlier has, so to speak, replaced eliminative materialism, but seems open to as serious an objection as eliminative materialism, that is we intuitively say, both of those views leave something out. If somebody says consciousness is merely electrochemical activity, we're convinced that they've left something out in their account of consciousness, and so with the functionalist picture.
I might add, that if it turned out, at some future date, that micro tubules in the brain were identified with consciousness, where their stuff was said to be consciousness, we would feel as strongly that something had been left out. But since Roger Penrose refuses to say whether he' s characterising consciousness in terms of this stuff, or merely saying that consciousness is based in this stuff, I don't know whether that point applies to him.
Roger Penrose : I think.....you.....I have never claimed I know what consciousness is, and I think that the programme is to try and understand what consciousness is through various reasons, okay philosophical argument, logical argument, mathematical argument, physical argument, psychological argument, and so on, neurophysiological arguments. But I'm not saying I know what it is, so I don't think it's fair to ask me this question (laughs) to define it, or anything like that. I don't think it's micro tubules, that's not the point. The point about the micro tubules is that they are the best bet that I know of in making use of the various aspects of the physical world that I think we're going to need to call upon.
Melvyn Bragg : Ted Honderich can I ask you, do you think that physics at the level practised by Roger Penrose and people, has got absolutely nothing to offer to the philosophy of consciousness? Because you seem to be banging down on it all the time.
I mean I'm an outsider, I'm in....but the impression I'm getting....do you think there is nothing to offer? Do you think that....do you think that the mind is not available to the sort of investigation which Penrose has claimed -no more than an investigation -that he is conducting? That there is something that philosophers can discuss, assume, take as their agenda, which is the agenda of themselves alone.
Ted Honderich : I think, I thought with just about everybody else, that consciousness or mental activity, let me simply say consciousness is related to the brain, that is part of the explanation of somebody's being conscious, is brain activity, and indeed this is a well held and well researched view. But while it's the case that physics will contribute more and more to that account of the basis of consciousness, I think nobody thinks that consciousness consists in electrochemical activity. Roger Penrose doesn't say so.
Melvyn Bragg : D'you think that consciousness....?
Ted Honderich : So if it's the case that consciousness is other than brain activity, then no matter the amount of science that goes into investigating activity you won't have got a conception of consciousness from it.
Melvyn Bragg : But you seem to me to be very close to saying that no "matter" that can be discussed or described, can describe consciousness. That it's not ...it not something that we can.....that can be discovered through discovery of matter. Whatever matter, however tentatively, Penrose has put forward as a possible explanation for consciousness, you say "Well no that doesn't get us anywhere".
Ted Honderich : I think that his view is...his view...well I'm not quite sure what his view is. It's a little hard to pin it down. But I think...
Melvyn Bragg : But I think the fact that it's hard to pin it down, is part of his view.
Roger Penrose : Yep.
Ted Honderich : Mmmmm, well....
Roger Penrose : We don't know what it is.
Ted Honderich : ...maybe I'd have pinned it down before he arrived at for discussion then and before he wrote his book!
Melvyn Bragg : No, no, no, no, no, that is....
Roger Penrose : (laughs)
Ted Honderich : But does need pinning down.
Roger Penrose : (indistinct)
Melvyn Bragg : One is allowed to have honest doubt in religion, I don't see why it shouldn't apply to physics as well.
Ted Honderich : Well honest doubt is alright, mean I'm very happy that he should have honest doubt, and I certainly have honest doubt about his views. But it is....it is.....
Melvyn Bragg : Well do you have any honest doubt ....do you have any honest doubt about your own views, as a matter of interest?
Ted Honderich : I have great honest doubt about my own views, but let me tell you what the view is and perhaps you'd like to bat it around a little bit. Alright?
Melvyn Bragg : Sure.
Ted Honderich : Erm, if you ask me, what it is for me, or Roger or you now to be conscious, or conscious of this room and we reflect on that, and we all do have a grip of what it is , and we all think incidentally that it has a lot to do with the brain , it seems to me that the most persuasive first answer you can come to, is that what it is for me to be conscious of this room, is for this room, in a way to exist, yes?
Now you're perhaps likely to hear that sentence in a way that suggest something like this -I'm not making any advance, I'm not giving any analysis of what it is to be conscious of this room, because I'm merely saying that a world exists in some metaphorical sense, and so there's no real explanation of what consciousness is in talking about the existence, in a way of a world, and they are perceived by us, and the atoms are in space, not perceived by us, but they are causal with respect to the sulphurs. Now if you think of the perceived part of the physical world, the sulphurs, that world, in a sense, depends on our perceptual apparatus. Bats for example don't have the capability of .......having an appreciation of visual properties of the world.
So the physical world, in it's sulphur part depends on us generally, and if you now go back to the world of perceptual consciousness, my world of perceptual consciousness, that depends on me, but the fact that it depends on me, shouldn't turn it into a mental world , any more than the fact that the perceived part of the physical world depends on all of us, or perceptual apparatus, turns that into a mental world. So I really want to say that the answer to the question of what perceptual consciousness is, is that it consists in the existence of a world which has a particular dependence on the perceiver.
Melvyn Bragg : D'you think that that explanation allows your investigation to continue in the way that you're setting about it? Or does it run.......
Roger Penrose : I think.....(laughs)
Melvyn Bragg : ...contrary to what your trying to do.
Roger Penrose : I think I have more trouble understanding Ted's view than he's having understanding mine, here! That I really don't under.....I don't see how our....you can explain what consciousness is from somehow.....I mean you seem to be attributing the existence of the external world to our consciousness of it, which.....I don't think you're saying that are you? But it's the way it sounds, and so what about different individuals? You have two or three individuals all perceiving the same sofa, are there several sofas or is there one sofa?If there's nobody in the room and there's still a sofa, is there still a sofa there?
Ted Honderich : If one asks "What is it to be aware of this room?" and I answer "It's for a world in a way to exist". That world depends in part on the perceiver and in part on that other world, the world of atoms , the physical world in it's other part.
Melvyn Bragg : But how can...... ?
Ted Honderich : It has that dual dependency.
Melvyn Bragg : What are we bringing to bear on our perception? What is our perception? What is the stuff out of which our perception comes? Is there stuff? And if there is stuff, why can't Roger Penrose's investigation be getting somewhere near it?
Ted Honderich : Well....
Melvyn Bragg : Can you answer that Roger? Because I can't.
Roger Penrose : (laughs) Well...yeah...well go ahead if you can say something about that, yes.
Ted Honderich : Perhaps this may or may not help. It's just a direct question to Roger Penrose. Is consciousness in the brain?
Roger Penrose : Well, it's a phenom.....it's a feature of the brains activity, no doubt about that. But you want to identify...you want to locate it in a certain place? Is that the idea?
Ted Honderich : I'm just asking whether on you view it's true that consciousness is in the brain?
Roger Penrose : Well when you say "in" I'm very confused by that, because...I mean it's a phenomenon...
Ted Honderich : Your easily confused.
Melvyn Bragg : Hold on hold on , let him finish.
Roger Penrose : .....it's a part...it's a phenomenon which is an activity of the brain, yes. I mean it wouldn't be there, if the brain wasn't there. But you want me to locate it with spatial coordinates or something is that the idea?
Ted Honderich : Well....
Roger Penrose : Because it's not a local thing, I'm sure it's not localised.
Ted Honderich : It would help me to understand your view if you directly answered that question , because on one understanding of your view, consciousness does seem to be in the brain, it's matter of these micro tubules. Where "a matter" means, it more or less is these micro tubules, and that seems to me.....
Roger Penrose : It isn't the micro tubules. I don't mind it being located......
Ted Honderich : That seems to me to be an extremely unlikely idea.
Roger Penrose : I'm not saying it is the micro tubules, I never said that, I think you keep bringing it back (laughs) to that, and I'm not saying that.
Ted Honderich : But the alternative view is a truism, which is just to the effect that consciousness, whatever it is, and you're know saying you don't know what it is, is somehow based in the brain, we all knew that, it's been true for a century.
Melvyn Bragg : Last word to Roger Penrose.
Roger Penrose : I think we're going to have to learn a lot more about what the physical world is like, this is the trouble. I mean I think you have a very archaic view of what the physical world is like . We've got to know more about that, before we can answer these questions.
Melvyn Bragg : Well that's true (laughter). Thank you very much, well I enjoyed that, and her thank you very much Roger Penrose....
Roger Penrose : Thank you.
Melvyn Bragg : ...thank you very much Ted Honderich, and thank you for listening and there you go! (laughs)
For more on Ted Honderich's theory of consciousness go to Radical Externalism.
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