2011-09-20 Bloggingheads TV with John Horgan
Duration: 01:07:55
Transcript
John Horgan
Hello, David Deutsch? Are you on the other end there?
David Deutsch
Yes, hello.
John Horgan
It’s great to have you here on Blogging Heads, David. Let me just introduce myself and then I’ll let you do the same. Okay. I am John Horgan. I’m a science journalist and occasional science correspondent for Blogging Heads TV. And I have a really special guest with me today. The physicist, British physicist, David Deutsch, who is now in, you’re in Oxford right now?
David Deutsch
That’s right.
John Horgan
So David, could you just give us a little background on yourself and then we’ll start talking about your wonderful new book.
David Deutsch
Certainly. So my name is David Deutsch and I’m a physicist at Oxford University. And I’m the author of two books, The Fabric of Reality and recently The Beginning of Infinity.
John Horgan
David, you were often described as a pioneer of or even the father of quantum computation. And that’s been a theme in both of your books. Can you just describe a little bit about how you got into that field? Which I think was quite a while ago, a couple of decades ago.
David Deutsch
Yes, it was actually I actually began thinking about quantum computers in the 1970s, although I didn’t call them that then because I didn’t think of them as being anything to do with the foundations of computation. The context there was the so-called parallel universes or many universes interpretation of quantum mechanics. And I had realized that the consensus view that both the proponents and the opponents of this rather controversial interpretation had been taking, namely that it is just a matter of interpretation and that there are no possible experimental tests of it, was actually false. And that this idea that it can’t be tested was simply due to some poor thinking about what would happen when an observer did a measurement on another observer and so on. And so I was trying to clarify this issue of what an observer is in quantum mechanics. And so I thought, well, the simplest way to clarify that is to imagine an artificial observer and what would be called an AI or an AGI, an artificial general intelligence, but running on the hardware that obeys quantum mechanics. Of course, all hardware obeys quantum mechanics, but I was thinking of hardware that obeys it in a way that can be tested in the laboratory. And so I imagined an AI program running on this quantum hardware. And then I added a few extra elementary operations to this computer, which would be sorry, that was OK. OK, they’ll have to cut out this bit.
John Horgan
That’s OK. It’s those little glitches that make blogging heads so charming to some people.
David Deutsch
OK. Yes, so that I had to add a couple of extra operations to this computer because that’s what made the difference between doing this experiment with a computer that obeys quantum mechanics and an ordinary computer, the kind of computer that we know that we’re familiar with. And given those extra operations, it was possible to perform an experiment whose outcome would be one way if there was only one universe, if something like the Copenhagen interpretation, the wave function collapse interpretation or any single universe interpretation of quantum mechanics were true, and would go another way if the many universes interpretation was true. And so as a sort of side effect of this, I realized that quantum mechanical computers would be inherently more powerful than they could perform more qualitatively different computations than classical ones. And then later, yes, later.
John Horgan
Yes, maybe you should just back up. And we can’t assume that our listeners are completely familiar with all the different interpretations of quantum mechanics. Just remind us of what the many worlds or many universes interpretation of quantum mechanics is and how it differs from, say, I don’t know, the Copenhagen interpretation. If that’s kind of the more mainstream view of what quantum mechanics means.
David Deutsch
To explain what quantum computers are, I have to explain what quantum mechanics is from my point of view. And I adhere to what’s called the parallel universes or many universes interpretation proposed by Hugh Everett in 1957. It says that the universe we see around us is just a tiny facet of the whole of physical reality, and so if we want to retain the same word for universe, we have to invent another word for the whole thing. And I favor the word multiverse for the whole of reality. This, in my view, and in the view of its other proponents, is an incontrovertible implication of quantum theory, which is our most fundamental theory in physics. But I always have to warn the viewer immediately that this view is shared by perhaps fewer than 10 percent of theoretical physicists. At any rate, that’s what I take quantum theory to say. And quantum computers are computers that harness quantum theory to perform a different mode of computation, something that cannot be performed by existing classical computers at all.
John Horgan
I see. OK. I want to come back to multiverse theories and the multiple universe interpretation. But let’s let’s talk about your book. Now, I’m holding up the galleys that I got from the Wall Street Journal when I reviewed your book, The Beginning of Infinity. And I should say that the journal, I think, asked me to review your book because it is almost the antithesis of a book that I wrote in 1996, The End of Science. And in fact, at the very end of your book, you mentioned my book and reject its claim that science might be approaching its limits very forcefully. I think the journal expected me to lay waste to your book. They thought that that would be entertaining. And I fully expected to do that when I started reading you. But I ended up really loving your book. I think it wasn’t what I expected at all. It’s a really grand vision of human possibility. And it got me questioning my own pessimism about the future of science and even technological progress. So could you just tell us what where did this where did the idea for this? First of all, say, give us a nutshell version of the book’s theme and then and also say, give us some sense of where the ideas came from.
David Deutsch
Yes, the basic theme of the book is that all human progress in the past has been fundamentally caused by a single kind of activity, which I call the quest for good explanations. Explanations being accounts of some kind of reality and how it works and why. And pursuing this theme of what an explanation is, why the quest for good and good explanations can work and so on. It makes contact with the whole lot of other bits of science and philosophy and so on, which together imply that this process need never come to an end. That is, we could bring it to an end if we destroy ourselves or decide not to or whatever. But there are no inherent limits to the growth of knowledge and therefore to progress. And by the way, you mentioned your review of my book. I thought it was exceptionally nice, generous review. But it’s funny you should mention your feelings on reading it because they were exactly mirrored in my feeling on reading your book. I was expecting to hate everything in it, but instead I merely disagreed with the conclusion. It seemed to me, correct me if I’m wrong about this, but it seemed to me that in every argument in your book, there is a sort of reluctance. There is a wish that it were otherwise and that your arguments about these limits, you are forced to them because you think that that is the logic of the situation. But you would rather that it were otherwise. And that’s that’s what I got from your book.
John Horgan
Well, of course, I mean, I became a science writer because I see science, as I think you do, as by far our most powerful way of understanding ourselves and understanding all of reality. And I actually got into science journalism in the early 80s when there was talk of a theory of everything. Stephen Hawking had predicted the end of physics. There would be this great revelation at the end of our quest to understand everything. And I was enormously disappointed when, after a period of time, I started suspecting that maybe science was already bumping into walls and we wouldn’t get these great revelations in the future. So you’re absolutely right.
David Deutsch
I think these walls are of our own making. They’re not inherent in the subject. I mean, this is my subject. The book covers all subjects. And by the way, not only science, I think this thing about the quest for good explanations has been responsible for all progress, such as moral progress, political progress, artistic progress of every kind. But science is my field and physics in particular. And it is true that progress in fundamental physics reached an all time high in the early 20th century. And although it hasn’t, it’s by no means gone to zero now, it is lower now than it has been at any time in the past. And this has caused some people to think that we may be running out of either we may be reaching the end as you I mean, in your book, you give both possibilities. Either we’re reaching the end of all knowledge so that we’ll understand everything, or we’re reaching the end of the capacity of science to create knowledge. And either way, we’re heading for a brick wall. Now, I think this apparent brick wall, as always in the history of knowledge, was not caused by anything in the subject. It was caused by what people have chosen to do. And you mentioned the theory of everything. To me, which is the proposed or hoped for theory of all elementary particles, space, time and gravity. That theory to me, it should not be called the theory of everything. That is a very tiny facet of physics from my perspective, let alone everything. It’s just the theory of how objects behave. But beneath that, you see, all such theories are formulated within a certain profoundly significant language and conceptual framework, namely quantum theory. And the theory of everything just assumed that quantum theory would survive, would be exactly the same theory after we have discovered this great unification. And also that essentially that the theory of gravity also would and that unifying them would simply be finding a way of writing either of them in the language of the other. And that has been the technique of elementary particle physics for the past several decades. And to me, that is simply what they’re doing is they’re trying to formulate a classical theory, not counting quantum mechanics, as if it was all in one universe, as if there weren’t interference phenomena and tunneling and all those things, just a classical theory. And then they apply a process that physicists call quantization, which is a way of transforming a classical theory into a quantum theory. And so you turn the handle. It’s just a mechanical process. And this worked for electrodynamics. That was that was the great achievement of Richard Feynman and Julian Schwinger and others. And it really hasn’t worked since. And I don’t think there’s any reason to believe that this process will ever work again.
David Deutsch
It was just a stroke of luck that quantum electrodynamics can be obtained from classical electrodynamics by a mechanical process of quantization, plus a whole load of cleverness.
John Horgan
But I don’t see why you’re skeptical of I assume that that would lead you to be skeptical of string theory and even loop quantum gravity and some of the main contenders for a theory that could unify relativity and quantum mechanics.
David Deutsch
Yes, unfortunately, I although I wouldn’t say these things aren’t worth doing, because if nothing else, we learn from them even when they fail. But it seems to me that progress, because progress comes from good explanations, it has to come from problems, because an explanation is an explanation of something like how a thing can possibly be. And that means that the prevailing way of trying to find fundamental theories in physics is unlikely to succeed because it is looking for mathematical models and then trying to understand what that could possibly mean if it were a theory in physics. And I mean, even if you found the right theory that way, I think the chances are fairly low that you’d recognize it. Because how do you know which of those mathematical objects correspond to which objects in nature? We’re assuming that the future theory is going to still be based on things like particles, space, time, fields, and so on. But why should it be? Fundamental progress in the past has always involved new kinds of entity, new modes of explanation that weren’t thought of before. So, yes, I’m skeptical that these approaches, any of these approaches can work. And I think that’s why there hasn’t been this fundamental progress.
John Horgan
David, let me raise an objection to your optimistic vision of the future of science, which is actually based on my reading of what quantum mechanics has done in physics. You have a passage in your book where you recall, I think it’s Niels Bohr saying that anybody who thinks he understands quantum mechanics obviously doesn’t. And you reject that as a kind of know nothingness, which is surprising for someone like Bohr. But it seems to me that if you look at, sort of in a sociological sense, all the different competing attempts to understand what the hell quantum mechanics means, that you’d have to grant that even for the experts, the theory is quite confusing. On the other hand, it’s powerful. It does anything that you could want from a theory in terms of being able to predict experiments and lead to all sorts of amazing applications and so forth. And so it seems to me that you’re getting a split between science as giving us power over nature and science as a mode of understanding. And the understanding, and especially then if you look at the rest of physics as well, which has become for the average person extremely difficult to understand, very esoteric. I see science as really beginning in the 20th century becoming more and more distant from the comprehension of the average person. And I just wonder where your optimism comes from that somehow in the future, I don’t know, as a result of new ideas in physics, new ideas about how unification should take place or whatever, why we should get the comprehension that seems to be retreating now in the past.
David Deutsch
Yes. In my view, this split that you talk about between quantum theory as a powerful technique for building things and making predictions and quantum theory as a way of understanding nature, this split is not a feature of quantum theory. It is a feature of the sociology of science during the 20th century. The split was introduced as a matter of philosophical dogma in order to protect from criticism the bad explanations that the founders of the theory and subsequent physicists have favored for quantum theory, which, by the way, from the many universes point of view, they are all equivalent to saying, well, at some point when we’re not looking, all the universes but one suddenly disappear. And we can’t notice this because we’re not looking. And that sort of thing. And when the response to careful, considered criticism of this view is to say, oh, well, you don’t understand quantum mechanics. Now, the thing is we’ve been here before. As Hugh Everett, the founder of the many universes theory, pointed out in a famous letter, we have been here before. A radical change in worldview was occasioned by the discovery of the heliocentric theory that the sun and not the Earth is the center of the solar system, what we now call the solar system. And Galileo championed this theory. And in the famous conflict between him and the Inquisition, they tried to force him to renounce the theory. But if you look in more detail, what they were asking him to renounce was not the power of the theory, not its ability to predict that they were quite willing to allow him to espouse and to teach and so on. What they wanted him to reject was the claim that this described reality, that this described the solar system. And the new vision of the solar system that was entailed by the heliocentric theory was a jarring change from what had gone before. Because, for example, it meant that the Earth beneath our feet, which is the paradigm of something fixed in common sense, is actually moving very fast. It’s moving at a thousand miles an hour around the Earth’s axis and also moving around the sun. And we can’t feel this because the laws of physics are constructed in precisely such a way as to cancel out any feeling that we might have about this motion. And people who at first sight, this is a ridiculous idea because it’s like what Lewis Carroll said. I was thinking of a plan to dye one’s whiskers green and always use so large a fan that they could not be seen. It was accepting one thing just in order to make it invisible and then explain something else and so on. And it’s only when you look very carefully at what the theory says that you see how much and how enormously better an explanation it is of the observed motion of the planets and so on. And then it allowed further unifications by Newton of celestial mechanics and terrestrial mechanics and so on. And so this split at that time was an invention of the Inquisition.
David Deutsch
The split in quantum mechanics, regrettably, was an invention of its very founders. They didn’t want to take the theory seriously as a description of reality.
John Horgan
Do you think that Einstein, if he was alive today or had lived long enough to see Everett’s theory, would have embraced it or would have made him even more frustrated with quantum mechanics and convinced that it had to be incomplete or wrong in some way?
David Deutsch
It’s hard to predict what an actual person would have said. But if we look at what Einstein wrote about quantum theory and wrote about his famous criticism and his great debate with Niels Bohr about quantum theory, all his criticisms are straightforwardly met by the many universes interpretation. So he only missed it by two years and it’s very, very frustrating. And Bryce DeWitt in his famous article introducing the many universe interpretation, in a footnote, he says that Einstein would surely have liked this. I think he would as well, because what was driving Einstein both in theory of relativity and in his critique of quantum theory as it was in his day was realism. He understood science and physics as being the study of what reality is like. And these equivocations that the quantum theory appeared to bring, namely, well, what do you really mean by real? And we can’t really say what’s real. We can only say what we observe about the reality and so on, in which case science becomes the study of us. It becomes the study of our perceptions and everything else is just a sort of fiction that he rejected rightly. Having, by the way, believed stuff like that in his youth and rejected it in order to make progress with relativity. He then applied that idea of realism to the whole of science and insisted on that and rejected the quantum theory of the time as not being realistic, whereas the Everett theory is entirely realistic. In fact, you can define many universe quantum theory as just the statement that the equations of quantum mechanics describe reality. That’s all it is.
John Horgan
Let me bring up another possible objection that Einstein might have had. Einstein has this wonderful phrase. I have no idea when he said it, but that the goal of physics is to determine whether God had any choice in making the universe. So it’s a way of getting at the question of why do we, okay, even after we figure out the laws of the universe and its history and so forth, we still have to ask why this universe? Why do we find ourselves living in a universe that allowed our existence and so forth? And it seems to me that, and there was a hope, Steven Weinberg has also talked about this, that there would be a theory at some point that would be kind of logically inevitable or necessary. And if you tried to tweak it, it would fall apart and it would and it would make this universe that we live in also necessary or inevitable in some sense. And what has happened over the last couple of decades is that things have gone completely in the opposite direction. And now you have theories that predict basically an infinite number of other universes. So you’re sort of back to the arbitrariness of this one. And the problem, as far as I can tell, has gotten even worse. So I wonder how you respond to that issue.
David Deutsch
So, first of all, if one interprets Einstein’s view, that quote of Einstein’s, as saying that we need an ultimate explanation, then I think that that is a chimera. I think that that will never be found and can never be found. And if such a thing could be found, it would be a catastrophe because it would be the end of progress. And progress in science is intimately connected with all the other kinds of progress. So it would also lead to the end of progress in the other ways that we like, such as morality, politics and so on. But I think there is nevertheless a truth in it, which is the truth about good explanations. What we want from a good explanation in the way I describe in the book is that it be hard to vary. That is, if you displace one note, as Shaffer said in the play Amadeus, then there’s diminishment. And if you displace a phrase, then the whole structure falls apart. So in that sense, a good theory must have a certain inevitability about it, with hindsight, of course. So with hindsight, you see that it couldn’t have been in any other way. But what saves us from the evil implications of an ultimate explanation is that good explanations solve the problems that they address, but they always raise new and better problems. So the problems that we have today, for example, in cosmology about what the dark energy is that’s making the universe expand at an accelerating rate, one of the most startling discoveries of science in recent times, that discovery depended on the previous discovery of the general theory of relativity and cosmological models in that theory and so on. It’s only in the light of those theories that we can even know that the expansion of the universe is accelerating and know that that’s amazing. So the solution in solving the problems that Einstein solved, namely how things like the motion of light and the existence of gravity could be reconciled in his general theory of relativity, that opened up problems that were simply inconceivable before. One couldn’t have expressed them even in the language of physics or in the language of common sense. They were problems that opened up because of the solution of previous problems. And that’s the solution to the conundrum, how we can get our hard-to-vary good explanations without grinding to a halt as a result. It’s because good explanations open up new problems.
John Horgan
Let me bring up another figure who’s very prominent in your work, the philosopher Karl Popper, who I was fortunate enough to interview a few years before he died. Obviously he’s been a very big influence on you. He has. And I just wonder how Popper would have reacted or did react. I don’t know if he ever wrote on multiverse theories. But I would suspect that Popper would have been a skeptic of multiverse theories because he was so insistent on testability. And it seems to me that multiverse theories are at the very least extremely difficult to test, and that any kind of evidence you would have of their existence would be circumstantial at best.
David Deutsch
Okay, yes, there are two issues there. One about the testability of the many universe interpretation and the other one about Popper. I was also privileged to meet Popper on one occasion when I was a student, and I was lucky enough to be invited along to a meeting between Popper and my mentor, Bryce DeWitt, my physics boss, Bryce DeWitt. And basically at that meeting, DeWitt told Popper that he had misunderstood what the fundamental problem is in quantum theory. And Popper thought it was to give a meaning to probability statements, and he’d kind of missed the deeper problem of things like entanglement and interference and the measurement problem. And Popper said that he had realized that he had an inadequate understanding and had held up publication of one of his books in order to try to improve it. Now, I’ve looked at his subsequent books and they all contain the same misunderstanding of quantum theory, unfortunately. He does occasionally mention the many universe interpretation, but only to dismiss it for kind of non-philosophical reasons, just to say, well, you know, we can’t have that and therefore I’m going to concentrate on this other thing. So Popper, unfortunately, like Einstein, died too soon, but not too soon chronologically. He just died too soon for the right understanding to have reached him. I suppose that is not a coincidence either, because 90% of the physicists whom he might have asked about the foundations of quantum theory would have given him nonsensical answers. Now, as for the testability of the many universes interpretation, as I said, there are in principle tests that would test it against the rival theory that there is only one universe, but really that is grossly understating the scientific status of the theory. The reason that one doesn’t normally test an interpretation. Normally in science one says that yes indeed the equations of the theory do describe reality. And it’s really only in the case of quantum theory within physics that somebody has said, how can we test the interpretation by itself? Namely, how can we test the statement that these equations, though we’re not disputing that they correctly predict experiments, how can we test the statement that in fact they represent reality rather than just what we see in reality? Now, as I said, we’ve been here before in physics, namely at the time of Galileo and the Inquisition, but in the present day there is a very close analogue of this, and that is the creationists who say that fossils, no one’s ever seen a dinosaur just like no one’s ever seen a parallel universe, all we have is the circumstantial evidence of fossils and the interpretation of fossils as being the remains of dinosaurs. Now similarly, we have no one’s ever seen parallel universes, but what we have seen is interference phenomena and the interpretation of interference phenomena as being due to the interaction of different universes, and there’s no other explanation. So if you want to say the other universes don’t exist, you have to do it by fiat, rather like the people who say that the world was created 6,000 years ago with fossils. So similarly, the conventional interpretations of quantum mechanics say that at the moment of a measurement, all the universes except one disappear, don’t exist, and no one can contradict this because no one can see them.
John Horgan
David, I’ll just tell you, I think that’s a stretch to compare doubters of parallel universes to, and I count myself one, not a doubter but more an agnostic and someone who thinks that it’s kind of a moot issue because we’ll never have good evidence, doubters of these things to creationists who aren’t sure that dinosaurs really exist. But listen, I want to get on to another really big topic that you raise in your book that I love.
David Deutsch
By the way, I was only saying that the logic is the same. The psychological motivation is not the same, but the logic is the same because of the existence of good explanations in both cases. But okay, continue.
John Horgan
All right. A really wonderful theme that emerged at a number of places through your book was, and I’ll put it into my own words and you can tell me if I’ve gotten it wrong, was a kind of critique of simple reductionism or materialism, which obviously is the kind of prevailing philosophy of physics that good answers will come from going to smaller and smaller scales and also focusing on things, on objects, on particles and so forth. Yes. And you seem to be, you are to my mind, saying that that is a much too restrictive form of explanation and that we have to recognize that what we might even call immaterial phenomena that aren’t reducible to specific physical objects or processes can have a profound impact and have had a profound impact on reality, particularly our human reality, human history, the world of politics and culture and so forth. And it seems to me it’s almost a rebuke of physics as kind of the really the best mode of understanding the world. And you’re emphasizing how important mind is and ideas are and thoughts and so forth. So talk about that a little bit.
David Deutsch
Yes, of course I am a physicist and I’m profoundly opposed to any idea of non-physical explanations that contradict physics. So that’s a no-no and really doesn’t make sense. However, there are ways in which both emergent properties such as minds and life and so on have an effect. And as you said, also abstractions. Now this, the fact that the theory of good explanations led to the idea that abstractions are real things was slightly surprising to me. I wasn’t expecting the link, at least wasn’t expecting it to be so strong as it is. But the thing is, if you think about how to explain events, physical events like a footprint on the moon, how do you explain how that happened? Well, it happened because of human ideas, of science and human ideas. You could say in this reductionist sense that, as you rightly say, is the prevailing mode of explanation and the prevailing idea is to look down on other modes of explanation, that those ideas are nothing more than configurations of atoms. So some physicists, some rocket scientists put their brain into certain configurations of atoms and those atoms then acted on other atoms which acted on other atoms which then ended up making a footprint on the moon. Now what that misses is the explanation of why certain configurations of atoms put footprints on the moon while others, the overwhelming majority of configurations that human brains, even human brains have been put into in history, do not have that effect and it’s because of, there’s a certain type of information. And this information can’t in my view be reduced to statements about atoms because if you think about what that information does, it is in brains but the same information then gets transferred into let’s say sound waves in air and then it gets transferred into ink on paper and then it gets transferred into magnetic domains inside a computer which then control a machine that instantiates those ideas in bits of steel and silicon and so on and so on. There’s an immense chain of instantiations of the same information and it’s only special kinds of information that have this property that they are preserved and instantiated in successive physical modes. So what is being transmitted, what is having the causal effect is not the atoms but the fact that the atoms instantiate certain kinds of information and not other kinds. So therefore it is the information that is having the causal effect. If a particular instantiation of that information were damaged then processes would come along to fix it, whether or not they could fix the physical instantiation, for example if the computer goes wrong then we don’t use the corrupted information, we go back and rescue the information from a different computer and we throw away the atoms that at one point instantiated it. So the information causes itself to remain in existence.
David Deutsch
Now I think there’s no way out of that mode of explanation and if explanation is going to be the fundamental thing about our criterion for example about what is or isn’t real then we have to say that information and this particular kind which we call knowledge is real and really does cause things.
John Horgan
It seems to me you bring up the word choice at a number of places in your book and you emphasize the power of human choice. It seems to me that what you are really doing is defending the concept of free will. Maybe you can tell me if I’m wrong here and as some of the listeners out there know I am a free will fanatic. I’m very upset that some prominent scientists recently have said that free will probably doesn’t exist. It’s an illusion. Stephen Hawking has said as much. Einstein in a couple of his quotes suggests that free will probably doesn’t exist. So you believe in free will I take it?
David Deutsch
I certainly do and I think that the argument against free will from reductionism is just a mistake. It’s a fundamental mistake. It’s the idea that all explanation must be in terms of microscopic things. There’s no philosophical argument in favor of that that I’m aware of. It’s just an assumption. It has historical roots in how science centuries ago escaped from the clutches of the supernatural. And as I said earlier certainly I’m opposed to any kind of modes of explanation in terms of things like immaterial things, in terms of abstractions that contradict physics. But the idea that all such explanations by their very nature contradict physics is simply false. I just gave an explanation of footprints on the moon in terms of the ability of certain types of information to preserve themselves in existence and so on, whereas other kinds don’t, and I defy anyone to reproduce in terms of atoms. And I also defy anyone to show how that contradicts an explanation in terms of atoms. So we have to accept the physical world as we find it. We have to find the best explanations that explain it rather than impose by dogma a criterion that explanations have to meet other than that they explain reality. So I think this reductionism, the fashionable reductionism is just a mistake. I’m sure that free will exists. However, I think free will is one of a constellation of emergent abstract, we’re not sure exactly what proportion of free will is abstract or emergent properties that are not yet understood. Things like consciousness, creativity, choice, free will and so on. We do have good explanations about them at the emergent level, but we don’t understand them well enough to make artificial ones. And I say in the book that my criterion for judging any theory of consciousness, free will and so on is can you program it? And if you can’t program it, then I cannot take seriously your theory of it. Now, I don’t have a theory of it. I only have a theory that it exists. Now, if someone says that it doesn’t exist because we can explain everything without invoking it, I want to see those explanations.
John Horgan
Roger Penrose, I assume that you know him, has proposed a solution to the mind-body problem involving quantum mechanics working in some way. Yes. To me, the mind-body problem and free will, which is obviously a big part of it, is the biggest unsolved problem in science. And people are just grasping at straws right now. So I just wonder if you see any even blue sky ideas that might provide a kind of framework for understanding it. Maybe also information theory, which some people have also tried to bring into physics.
David Deutsch
Well, as you said, Roger Penrose is looking for a new theory to replace quantum theory, which would not only be a better theory in physics than quantum theory is, but would also solve problems like the existence of free will and creativity and so on. I’m pretty skeptical, for the same reason that I’m skeptical of the mathematical approaches that are currently fashionable in fundamental physics. I think that one solves problems in physics by addressing problems that are in physics, rather than hoping that they have certain attributes, finding a theory with those attributes, and then hoping that it applies to physics. But, you know, I could be wrong, but at present there are no such theories. I think existing approaches to AI, artificial general intelligence, are all philosophically flawed. And I think that’s why they haven’t succeeded for decades, because they are… A philosophical advance is needed, and they are trying to get the answer without making any philosophical advance. And that leads them essentially to sort of behaviorist models of what… And behaviorist models are non-explanatory models. They are models that just try to relate output to input without explaining why the output comes from the input and so on. And I think that approach can’t succeed, and it’s the reason that this quest for AI has not got anywhere during the last decades. What we need is first philosophical progress in understanding how creativity, I think that’s the key thing that relates all these unsolved problems about free will, consciousness, and so on, how creativity is implemented. And it has to be implemented… We know a few things. It has to be, in the broadest sense, an evolutionary process. It has to work by variation and selection, or as Popper calls it in the case of science, conjecture and refutation, or conjecture and criticism. But we need to know the details, and the devil will be in the details. My guess is that once we understand what it is, we will be able to program it. I think there’s an analogy here with Darwin’s theory of evolution. Darwin’s great contribution, in my view, is not his scientific theory of evolution. It is the philosophical progress that he made in inventing a new mode of explanation. Not just a new explanation, but a new mode. Obviously, everyone who had addressed the question, why are animals the way they are? Why are there adaptations there? People try to address this by supernatural explanations and also by scientific explanations, but all of them took for granted that what you had to do is find a reason why there are elephants. Why elephants have long trunks, that kind of thing. Darwin realized that that is a bad way of approaching the problem. To understand why elephants have long trunks, you must not ask why they have them as your initial question.
David Deutsch
You must ask what kind of process could give rise to trunks. Then, that they have purposes, and some biological features have purposes, some have anti-purposes, like the peacock’s tail, and so on. That all comes out in the sophisticated elaboration of the basic theory of how it could possibly happen by variation and selection. By random variation, that is, undirected variation and then directed selection. Now, free will, consciousness, and so on, definitely involves that as well, but it involves something else that we don’t yet understand, which it will take a new Darwin to realize. And once a new Darwin has realized it, it will be… Well, it took many decades between Darwin and DNA. I think it would be much faster. The time between the person who discovers the correct philosophy of AI and the programming of AI will be a matter of months, not decades.
John Horgan
I hope I live long enough to see that. I also. That would be very exciting. In the limited time we have left, I want to make sure that we touch on some of the political themes that you raise in your book. I mean, it really is part of what I enjoyed about the book was that it was so broad, and you had these very powerful ideas, especially about accepting our fallibility as kind of a mode of constant self-improvement and applying that in all these different fields, science, culture, and politics. So when it comes to politics, I wanted to ask you whether or not you think that… You know, Francis Fukuyama had this… I had a book called The End of History where he’s saying that in a very broad sense, democracy plus free market capitalism represents the best we can do as far as finding a way of organizing ourselves. And I just wonder, although, you know, of course, there’s a lot of tweaking we can do. I just wonder if you agree with that or if you think that there could also be infinite progress in the realm of politics.
David Deutsch
The same arguments that I use in the book for everything else apply automatically to politics and imply that infinite improvement, unlimited improvement is a better word, is possible there too. The liberal democracy plus free market capitalism is the best known, our best existing knowledge of this. And so I would guess that Fukuyama, despite recent hiccups in his predictions, is right that the ideas that had been the main rivals to those ideas during, let’s say, the early 20th century, such as totalitarianism, communism and so on, that those are going into the dustbin of history. I think that is very different from saying that our best guess as to how to create new political knowledge is going to be just our current institutions. I’m sure that unlimited improvement is possible there too. For one thing, we haven’t solved the enormously important problem of how to transmit this knowledge to political cultures that don’t yet have it. And it seems that there’s something about our existing political culture that is actually antagonistic to transmitting it outside its natural home. So that will be a major improvement because, as Martin Rees said in his recent book in which he predicts that there’s only a 50% chance of civilization surviving the next century, progress in other areas, especially technological areas, means that smaller and smaller numbers of people are going to be able to do larger and larger amounts of damage. And so unless the means of promoting the resolution of disagreements without violence can be propagated to basically the whole world, we’re going to be in increasing danger from things like weapons of mass destruction in the hands of terrorists. By the way, I think this is not just a problem with improving our political system. It’s a general problem to do with technology and everything else because apart from trying to… I should say that our civilization, the civilization of the West, of liberal democracy and capitalism and so on, is within itself, inside itself, it is by far the most peaceful as well as the most rapidly progressing civilization that’s ever existed. But I think that apart from having to improve it further in order to allow it to survive, there’s another thing we have to do. And this is a big theme of my book as well. We have to continue to make rapid progress. And it’s not just for its own sake, but in this context, in this political context, it’s because rapid progress is the basic means by which the good guys can defend themselves against the bad guys. I’ve said that technology makes a smaller and smaller number of people able to cause larger and larger effects. Well, that has to be offset by the larger number of people, the good guys, making at least as much progress as that in order to be able to cause even larger effects in self-defense. So it’s rapid progress that is our only, our major means of self-defense against the instabilities caused by small numbers of bad people.
John Horgan
Okay, wait a minute. I’ve got to stop you there. That sounds to me like more arms races in the future. I, you know, we’ve already been down that path and produced nuclear arsenals capable of destroying all life on Earth many times over.
David Deutsch
Yes, that’s not the implication of what I was saying. That’s to interpret it in terms of the technology of the past. It’s a sort of reductionist interpretation, if I may say so. The kind of, for example, protecting ourselves against nuclear attack during the Cold War was done and rather imperfectly done by developing ways of nuclear attack ourselves. But protecting against, let’s say, biological warfare attacks has got nothing to do with, well, perhaps it also involves developing weapons as a means of developing antidotes against them. But it’s basically what we need in the case of biological warfare is antidotes, not weapons. I see. And antidotes are, and this is going to be increasingly so, as the complexity and knowledge in society becomes the thing that we need to protect. Once we have, for example, once we are able to download our minds from our brains into computers and so on, then physical protection of them will become much less important compared with protection of them from bad ideas, which would use creativity to destroy all the backups. And that is, I mean, I’m talking about the ultimate extreme of the process, which is already there in the fact that we, that defending against biological weapons involves not biological weapons, but antidotes. That kind of rapid progress is essential to the future of civilization.
John Horgan
One other, okay, boy, you’re just popping open cans of worms all over the place here, David, and we’re basically out of time. But I just wanted to make sure that we touched on at the very end here, your views on our environmental problems, on global warming, the question of sustainability. You, you’re quite critical of the concept of sustainability and also of what you might call, I don’t know, environmental alarmism. You recall hearing Paul Ehrlich give one of his gloom and doom speeches decades ago, and you were pretty dismissive because you thought that Ehrlich wasn’t anticipating any technological progress that might help us overcome these problems. So just give us a quick picture of your view on our sustainable or not sustainable future.
David Deutsch
So I think it’s a great pity that the issue of how to manage the environment has become a political issue, because as a political issue, it has become dogmatic and the dogmas on all sides are simply false. They contradict the arguments of my book, and what more can I say? On the one side, we have people who say that the only way of ensuring our survival in the long run is in damping down our impact on the environment. Now, damping down our impact on the environment is itself an impact on the environment. There’s no fundamental difference between changes that we cause, changes that it causes, or changes that we cause by trying to undo things that we have done. All those things require knowledge, all of them require technology, all of them are going to give rise to unknown problems in the future. And on the other hand, there are people who try to deny that physics is relevant if it contradicts the political dogma. And that’s not true either. It’s rather unfortunate that in the case of global warming, the exact details of how soon this is going to become a major problem depend on supercomputer simulations. The thing is that it is going to become a problem eventually, doesn’t need supercomputer simulations. It’s politically important whether the tipping point is likely to come in 50 years or 150 years. The difference between those is enormously important politically, but it’s not at all important technologically, it seems to me. It seems to me that in both cases, we need a very rapid progress and we need to assume that the solution is going to come from this rapid scientific and technological progress and that this won’t be the last problem that ever faces us. What strange arrogance it is among the opponents of arrogance in technology to assume that global warming is going to be the last major problem that will ever face our species. That seems to me ridiculous. And the task of technology is not to optimize the entire planet to solve one particular problem that we happen to know about, but to give us the means of, first of all, addressing problems that we do not yet know about. And secondly, the means to recover from disasters that will also inevitably happen when we make mistakes. And both those things, dealing with unforeseen problems and recovering, both those things require knowledge. And that’s why we need to increase knowledge as fast as we can.
John Horgan
One final question, and I’m sorry but your answer has to be fairly brief. I just wonder where your optimism comes from. I hope you don’t mind my saying. I don’t mean this as an insult, but it approaches a kind of faith. And I wonder if that faith has anything to do with a kind of spirituality on your part, a belief in, I don’t know, God or something?
David Deutsch
No, so, well, first of all, I deny it. I deny that I have any faith, religious or otherwise, and I deny that I have any spirituality. And I also deny that this optimism is an attribute of me. It’s as if you were saying, what kind of predisposition to multiplicity led you to become a defender of the parallel universes interpretation? That’s not how it happened. The reach comes from the ideas, not from what I want them to say. So I can no more deny the links between the theory of evolution in biology and in, let’s say, the human ideas, than I can deny that they apply to one particular animal. If the theory of evolution is true, then all animals evolved. And if somebody wants to say all animals except elephants, or as historically happened, all animals except humans evolved, then that doesn’t make sense as an explanation. And what I’m about, what my books are both about, is taking explanations seriously and requiring them to be good explanations, not requiring them to meet predetermined, to have predetermined implications.
John Horgan
Well, listen, there are a lot of pessimists out there. As you know, I’m sure you’ve gotten some pushback against your vision of the future. So I urge them all to read your book and give your ideas a chance, and it might even make some of those pessimists out there a little less gloomy.
David Deutsch
Well, that’s great, and I’m glad that you’re not one.
John Horgan
I’m working on it. Thank you very much, David. It was really a pleasure.
David Deutsch
Okay. Nice talking to you. All right. Same here.
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