# 2021-06-02 - Conversations with Tyler - Multiple Worlds and Our Place in Them [Official](https://conversationswithtyler.com/episodes/david-deutsch/) [YouTube](https://www.youtube.com/watch?v=b_6vYwCkIpc) [Apple Podcasts](https://podcasts.apple.com/us/podcast/david-deutsch-on-multiple-worlds-and-our-place-in-them/id983795625?i=1000523911995) Duration: 01:01:23 ## Transcript ### Tyler Cowen 00:00:00 - 00:00:34 Conversations with Tyler is produced by the Mercatus Center at George Mason University, bridging the gap between academic ideas and real-world problems. Learn more at mercatus.org. And for more conversations, including videos, transcripts, and upcoming dates, visit conversationswithtyler.com. Hello everyone and welcome back to Conversations with Tyler. Today I am with David Deutsch. David, welcome. ### David Deutsch 00:00:34 - 00:00:36 Hello. Good afternoon. ### Tyler Cowen 00:00:36 - 00:00:54 I have a question. I am myself a metaphysical agnostic. So I'm unwilling to step into a Star Trek transporter machine because I'm afraid it would kill me. And it's a copy of me that would keep on living. At what price are you willing to step into a Star Trek transporter machine? ### David Deutsch 00:00:54 - 00:01:03 I certainly wouldn't want to be the first person, but I suppose you're asking the question separately from do I think it would work technically? ### Tyler Cowen 00:01:03 - 00:01:11 Sure, assume it works as in the TV show. But metaphysically, there's a question you face. But you know you believe in many worlds theory, right? ### David Deutsch 00:01:11 - 00:01:39 Yes, though I don't think that is connected. I think it's more physicalism or something like that, that I believe that there's nothing to me except this running program in my brain. And if that program were to run somewhere else and stop running in my brain, then I wouldn't notice anything and I would indeed have traveled to that other place. ### Tyler Cowen 00:01:39 - 00:01:51 But say the world forks and it's possible both that you do and do not step into the machine. Isn't it the case that some version of the earlier you is still existing along one of the forks so you have nothing to worry about? ### David Deutsch 00:01:51 - 00:03:12 Some version of me, whenever I make a decision which could go either way, some version of me will have presumably made the other decision. Although that's not as simple as it sounds, because both the other version of me and me are error correcting entities. That's the whole point of what human thought is, it's error correction. Therefore, it will take more than just a cosmic ray hit to make the difference between deciding something yes or no. So this would have to be like an inconsequential decision, which unbeknownst to me, will have a large effect and then later cause me to be a different person and so on. And that's happening all the time, independently of Star Trek machines or anything like that. That is the case. And fortunately, it turns out at least if ordinary decision theory is true in like non quantum cases, then it turns out that ordinary decision theory with randomness produces the same rational decisions as quantum decision theory with the multiverse. So it shouldn't make any difference to decisions. And that includes the decision whether to use the Star Trek transporter. ### Tyler Cowen 00:03:12 - 00:03:21 Sure. So as long as there's a possible world where your atoms aren't scattered and you just didn't get into the machine, you don't have to worry too much about your decision. ### David Deutsch 00:03:22 - 00:03:59 I do, because when you say so long as there's a possible world, that glides over the question how many, what proportion of the worlds is that going to happen in? And what I said just now about decision theory in the multiverse, the proportion of the multiverse that does one thing or another plays the same role in decisions as probability does in theory where there's randomness. So it really does matter. And just because there are a few worlds in which X, Y or Z happens, if there are very few of them, they shouldn't affect my decisions at all. ### Tyler Cowen 00:04:00 - 00:04:12 How do we know what counts as a possible world? So there's a certain economy to a many worlds interpretation of physics. But isn't a lot of the complexity just being squeezed into this notion of what is a possible world? ### David Deutsch 00:04:14 - 00:04:17 Yes. And we're used to that. ### Tyler Cowen 00:04:17 - 00:04:18 I'm not used to it. ### David Deutsch 00:04:18 - 00:05:18 You are when you realise that different times are special cases of other universes. So when you make an economic decision, you're used to the fact that something you buy as some goods have a different value in different universes, that is at different times, even to the same you. So you might be slightly different, but even if you aren't very different, the value to you of something might be very different today from tomorrow. For example, oxygen, if you've got Covid, would be differently valuable. And most things change their value gradually over time. You change yourself gradually over time, and it's exactly the same in different universes. In different universes, you value different things. In some universes, you're so different that it's not worth calling you anymore, just like over time, it might not be. ### Tyler Cowen 00:05:19 - 00:05:28 I take it you don't believe in many worlds interpretations that there are 17 possible universes out there. You think there's a very large number, right? ### David Deutsch 00:05:28 - 00:05:30 Yes, extremely large. ### Tyler Cowen 00:05:30 - 00:05:40 So maybe you'll consider this question a kind of category error. But what is the process which filters what is a possible universe and what is not a possible universe? ### David Deutsch 00:05:40 - 00:06:04 Oh, the laws of physics. It's exactly the same as what filters, let's say if there's an explosion like a supernova, what determines the fact that different particles travel at different speeds and none of them travel faster than light? Well, it's all the laws of physics that determine what the distribution of speeds will be and what the limit will be. ### Tyler Cowen 00:06:04 - 00:06:11 How do we know what are the laws of physics for the multiverse? I mean, should we assume that they're the same as for the universe we live in? ### David Deutsch 00:06:11 - 00:06:20 So the universe we live in is demonstrably affected by things not in it. This is the lesson of interference phenomena. ### Tyler Cowen 00:06:20 - 00:06:21 Sure. ### David Deutsch 00:06:21 - 00:06:46 And so there's no such thing as the laws of physics for our universe. There's just the laws of physics. Of course, we don't know for sure what they are. But our best theories, in particular quantum theory, say that there are other such entities and how they affect ours and how matter behaves as a result of that. Of course, it might be overturned one day quantum theory, just like all our scientific theories may be. ### Tyler Cowen 00:06:47 - 00:07:01 This is again, maybe a question that you would consider a category error coming from common sense realism. But how should I think about splitting universes in a manner consistent with the conservation of matter and energy? Because there seems to be a multiplication. ### David Deutsch 00:07:01 - 00:08:10 Yeah, this splitting universes idea, although it was that kind of terminology was used by the pioneers of many universes quantum theory, such as Everett himself and Bryce DeWitt. Everettians nowadays don't speak of splitting. I myself prefer a picture where there's a continuum of universes, just like you might say, you know, there's a continuum of times or there's a continuum of geological strata. Underneath our feet and when a stratum splits in two, there's no definite point at which there was one here and two there. What happens is that the stratum becomes two strata gradually. So there's no point of splitting and the number of universes as it were, although you know, it might be infinite, but the measure of how many there are remains constant. And what happens during what used to be called a split is that some of them gradually change to one thing, while others gradually change to another thing. ### Tyler Cowen 00:08:11 - 00:08:23 How do you think many worlds interpretation of quantum mechanics relates to the view that just in terms of space, the size of our current universe is infinite and therefore everything possible is happening in it? ### David Deutsch 00:08:24 - 00:09:41 It complicates the discussion of probability, but there's no overlap between that notion of infinity and the Everettian notion of infinity if we are infinite there because the differentiation, as I prefer to call what used to be called splitting. When I perform an experiment which can go one of two ways, the influence of that spreads out first I see it, I may write it down, I may write a scientific paper and so on. And when I write a paper about it and report the results that will cause the journal to split or to differentiate into two journals and so on. But this influence cannot spread out faster than the speed of light. So an Everett universe is really a misnomer because what we see in real life is an Everett bubble within the universe, everything outside the bubble is as it was. It's undifferentiated or it's to be exact, it's exactly as differentiated as it was before and then as the bubble spreads out the universe becomes or the multiverse becomes more differentiated, but the bubble is always finite. ### Tyler Cowen 00:09:41 - 00:09:47 How do your views relate to the philosophical modal realism of David Lewis? ### David Deutsch 00:09:47 - 00:11:20 There are interesting parallels. As a physicist I'm interested in what the laws of physics tell us is so rather than in philosophical reasoning about things unless they impinge on a problem that I have. So yes I'm interested in for example the continuity of the self you know whether if there's another version of me a very large number of light years away in an infinite universe and it's identical is that really me are there two of me that one of me. I don't entirely know the answer to that and it's why I don't entirely know the answer to whether I would go in a Star Trek transporter. But the modal realism certainly involves a lot of things that I don't think exist at least not physically I'm open to the idea that non physical things do exist like. The natural numbers I think exist. There's a difference between you know the second even prime which doesn't exist. And the infinite number of prime numbers which I think do exist so I think that there is more than one mode of existence. But the theory that all modes of existence are equally real I see no point in that so the overlap between Everett and David Lewis is I think more coincidental than illuminating. ### Tyler Cowen 00:11:21 - 00:11:42 So if the universe is infinite and if David Lewis is correct should I feel closer to the David Lewis copies of me the copies or near copies of me in this universe or the near copies of me in the multiverse it seems very crowded all of a sudden. So something whose purpose was to be economical doesn't feel that way to me by the end of the metaphysics. ### David Deutsch 00:11:43 - 00:11:52 It doesn't feel like that to you well as Wittgenstein is supposed to have said I don't know whether he really did if it were true what would it feel like. It would feel just like this. ### Tyler Cowen 00:11:52 - 00:12:15 What about the alternative view that it's a big sprawling mess we're not capable of understanding an integrated theory. There's maybe some Darwinian principle operating across some different kind of multiverse our universe persists just because it works well enough a bit like a bad used car we're never gonna grasp it there's not a unified theory and here we are. ### David Deutsch 00:12:15 - 00:12:35 Okay well that's a mixture of the anthropic principle which I disagree with and the idea that some features of reality are inherently incomprehensible which I also disagree with I can't think of a connection between the two. So well if you want me to go into this I can go into either of them but. ### Tyler Cowen 00:12:35 - 00:12:45 What take the incomprehensibility of the universe and possibly multiverse so we would both agree it's incomprehensible to your cat right or to the local raccoon. ### David Deutsch 00:12:45 - 00:12:49 Yes but everything is incomprehensible to a cat. ### Tyler Cowen 00:12:49 - 00:12:54 I don't think that's true no dogs understand human social life pretty well. ### David Deutsch 00:12:54 - 00:13:40 They do not dogs have genes. Which contain knowledge but it is fixed knowledge and it is not the kind of knowledge that constitutes understanding is always explanatory. So you know you can write a book on canine behavior and look in chapter thirty seven and it will tell you. What a dog will do when such and such happens to it. And sometimes it will say some dogs will do this some dogs will do that there is no such book for humans because chapter thirty seven will be blank it'll say humans are going to do something that neither we nor you can predict. ### Tyler Cowen 00:13:40 - 00:13:45 I feel I can predict humans better than cats often but do chimpanzees understand in your view. ### David Deutsch 00:13:46 - 00:17:46 No one knows they show virtually no sign of understanding anything there are some really nice experiments on wild gorillas. By Richard Byrne who's both a theoretical and very practical animal behavior expert and he was wondering how gorillas transmit their memes that is their culturally inherited behaviors from one gorilla to another. So one thing is the first answer is very slowly it takes absolutely ages months and months for a gorilla to be able to copy another gorilla's behavior well enough to do something complicated I mean they can copy. You know wave hand and that sort of thing but to copy a complex behavior like required to open a difficult kind of nut which no other animal can open. This is why they have memes because that's a very useful ability it takes them a long time and then he did some ingenious experiments or rather observations he didn't interfere with the gorillas he did some observations. To try to determine whether they understand why they are doing each particular action and it involves you know I don't know what it involves grabbing with both hands and twisting in one way and then pulling another way and then and so on. Apparently these gorillas are prone to a certain injury which disables their thumb. And so they can't move their thumb which is quite disabling for them just as it is for us and the thing is when you disable your thumb one of these motions becomes irrelevant. And the others become less effective but the gorillas which have learned how to do the thing will make the motion the ineffective motion again and again every single time. And he explains this better than I do but that's like human beings borrowing at high interest rates right they'll do that many many times in a row not just like it you know you might like to draw analogies. But it's not the same thing when a human being repeats a behavior that another human being thinks is unwise or counterproductive or will not achieve its purpose and you ask them or you show them they will have an explanation which you might not like it may be stupid but the ape perfectly well wants this thing to work. But doesn't know why it is doing the actions. It's a thing that's very hard to take on board because we are used to intentional behavior. We're not used to the overt behavior of humans being unintentional humans tend to explain themselves even irrationally and they act according to their explanation. Whereas there's no evidence that any other animals have those explanations there's also the case of squirrels which is in a way even more amazing you know squirrels bury nuts so they can dig them up later. Well some people did a very cruel experiment they put a squirrel and given some nuts or something I don't know how they set up the experiment on a concrete floor. And the squirrel did exactly the same behavior with its hind legs with the nuts and put the nuts there and so on even though it was having no effect whatsoever. So we see the point of scrabbling with your hind legs and then nudging the nuts over there and so on but it doesn't it's just a program being enacted by its genes. ### Tyler Cowen 00:17:47 - 00:18:02 What is the underlying physical assumption that makes humans different in having explanatory power one would expect it to be a continuum if you're an atheist right what break occurs at some stage in evolution that's a discrete break or why aren't we just back to it being a continuum. ### David Deutsch 00:18:03 - 00:20:04 So I don't think it can have been a discrete break because evolution would have happened gradually my best guess we don't know this we have very little. Actually we have very little knowledge about the prehistory of ideas. Because there's no evidence of it all we see is the stone tools you know we don't even see the wooden tools because they've they've decayed away I think what happened is that the capacity of the brain. To store memes to store programs in the brain rather than the genes increased for some reason very fast because for some reason these memes are very valuable we know that the gorilla memes are very valuable because they allow them to gain knowledge of things like how to open nuts and so on which no other animal in their environment has so that gives them access to food. That no other animal has so the capacity for memes increased rapidly and there's very little now sorry I left out a step once memes get beyond a certain complexity they cannot be copied. We don't have the ability to download a program from another person's brain all we can do is look at the behavior. And guess what the purpose was and complex memes have to be transmitted like that rather than by aping which is a different process mediated by what are they called mirror neurons and that kind of thing that will only do for very simple behaviors and then. There came a moment when our species was capable of explanatory knowledge but they never used it for further tens or hundreds of thousands of years they just use it for this meme transmission. ### Tyler Cowen 00:20:04 - 00:20:27 I'm still puzzled as to why you think it's so unlikely that the universe is not comprehensible so take a simpler system like the distribution of prime numbers I'm quite sure I can't understand that and even if various conjectures were proven or not proven I think at the end of the day I still am not capable of understanding that even how certain motors work or markets for copper why can't that apply to the universe also. ### David Deutsch 00:20:27 - 00:21:43 Again this is the wrong standard that is true of everything there's nothing that we can fully understand in that sense in the sense that you want to fully understand prime numbers all the way up to infinity that's not what we mean by understanding things and that's not what I mean by the universe or mathematics. Being comprehensible I mean that there is no barrier there is no limit set by the universe that so far you can go and no further. So we can understand things better we can never understand things fully and I think thinking that there is such a barrier is absolutely logically equivalent to believing in the supernatural. Because everything that's past that barrier is just the same as it would be if zeus reigned and determined what everything after that barrier is and worse. The stuff outside the barrier of course is going to affect us even if we can't understand it so it's exactly the same as believing in a universe with supernatural beings. Who have it in for us because they put up this wall that we can't cross if they took down the wall we could cross it couldn't we. ### Tyler Cowen 00:21:44 - 00:21:54 How do you think about the various paradoxes of self-reference that arguably underlie number theory set theory right there's also Gödel's theorem any other results I'm sure you know them better than I do. ### David Deutsch 00:21:55 - 00:23:16 So I think Gödel's theorem for example and with its roots in self-reference paradoxes show us that even within pure mathematics. There is no such thing as a solid foundation for all our knowledge and therefore there's no such thing as fully comprehending everything. So we might think that we're pretty sure what the laws of arithmetic are you know we're pretty sure that we can see that. Three times seven is the same as seven times three by just laying out beads on the on the table but we can't ever. Lay out beads on the table to tell us that x times y is the same as y times x. Regardless of what x and y are and yet we can know that and the way we know that is by proving it and we prove it from the axioms using rules of inference. How do we know the rules of inference are true we don't they are conjectures they have exactly the same status. As laws of physics that we conjecture so we never know anything for certain we might be mistaken about anything. On the other hand we can have knowledge I think we also really do know that x times y equals y times x even though we have no solid foundation for that. ### Tyler Cowen 00:23:17 - 00:23:21 What in your opinion is the best test of the many worlds interpretation. ### David Deutsch 00:23:21 - 00:23:51 So the best feasible test is any interference experiment there is no interference experiment with individual particles that has an explanation other than Everettian quantum theory. You can make a prediction without making explanation that you can do but if you want an explanation of what brings about the outcome that you see there is no alternative but the Everett interpretation. ### Tyler Cowen 00:23:51 - 00:23:56 Well but most physicists don't believe in the Everett interpretation right ### David Deutsch 00:23:56 - 00:24:23 Yes very sad state of affairs that I'm at a loss to explain it's a sociological phenomenon though not a scientific or philosophical disagreement. It's something has gone wrong just like something went very badly wrong with philosophy as a whole in the twentieth century. And we're still seeing the ripples from that with postmodernism and woke and what have you. ### Tyler Cowen 00:24:23 - 00:24:46 I worry a bit you're using an argument from elimination so all the other views out there which personally I don't find convincing as an amateur but I can certainly see why you might reject them to me they look arbitrary. Those you reject but the other physicists who are as trained as you are some are as skilled as you are feel the same way about the many worlds view but what makes your intuition better than theirs. ### David Deutsch 00:24:46 - 00:26:37 Yes I don't think that so it's not a matter of intuition physics got dominated or contaminated by positivism instrumentalism and such like bad philosophical theories towards the end of nineteenth century and beginning of the twentieth century. And this caused a knock on effect on physics it almost had the same effect on relativity but Einstein rebelled against it at the last moment as it were and said no it really is true that space time is curved it's not just that our brains. Think that it's curved or something like that or that the predictions come out right. There really is a curvature in space time by the time quantum theory came along couple of decades later positivism instrumentalism and so on had taken hold. As a result generations of physicists were taught when they were students they were intimidated by their professors telling them things like. If you think you understand this you don't there is no such thing as what really happened if you ask how did the electron get from here to here you're asking an illegitimate question there is no such thing as how it got from here to here there is only a prediction that it got from here to here. Now when you're taught like that and intimidated by those kind of things coming from on high some proportion of you of young people will some will quit. Some will take that on board and do the same to their students in turn and some will think no that's ridiculous come on there is there is a thing and then they discover that there's an Everett interpretation. ### Tyler Cowen 00:26:37 - 00:26:44 Let's say we polled only the Popperian physicists including Popper himself what percentage of them would side with Everett ### David Deutsch 00:26:44 - 00:26:48 That's an extremely good question so Popper did not ### Tyler Cowen 00:26:48 - 00:26:53 Yes I know but that means philosophy can't be where people are going wrong right. ### David Deutsch 00:26:53 - 00:28:15 I think it can be I think it can be and is at the time when Popper wrote his rejection of the Everett interpretation very very few physicists had written about it. I say very very few I mean like three and they weren't philosophically very sophisticated. So the kind of argument that Popper heard about the dispute were all about the wrong things and he developed his theory of propensities because he thought that the problem was what can a probability possibly mean. In a universe that develops deterministically and so on and he didn't ever hear a real argument. About it I once met him in the company of Bryce DeWitt who is one of the other Everettian physicists and we told him that what he had written about Everett was just plain false he didn't understand the import of the experiment that was being discussed basically the well two things interference experiment and the Bell inequalities experiment he didn't really he was focusing on a different problem. By the time we came out of that meeting we thought we'd persuaded him but we evidently hadn't because subsequently kept on saying the same thing ### Tyler Cowen 00:28:15 - 00:28:22 So maybe he was just being tactful why do so many professional philosophers not think so much of Karl Popper. ### David Deutsch 00:28:22 - 00:28:57 Oh that's a so you know you just asked me why so many people make fundamental mistakes about metaphysics within physics what why do so many physicists. Talk nonsense about metaphysics and so now you're asking me why do so many philosophers make mistakes I've heard a variety of theories about this. But I don't know, and I haven't thought all that much about it but it is definitely the case philosophy took a really bad turn just over a hundred years ago and hasn't really recovered. ### Tyler Cowen 00:28:58 - 00:29:21 Professional philosophy I mean but say when I read Popper if I look at the areas I know best that he wrote on The Poverty of Historicism Open Society and Its Enemies. I find I agree with a very high percentage of his conclusions so I'm inclined to like him. But I don't think those are great books I think he's too obsessed with rebutting crude Marxism he's very bad at steel manning his opponents. ### Tyler Cowen 00:29:21 - 00:29:27 And on a lot of the pages I just don't find that much insight even though I'm very sympathetic toward the conclusions ### Tyler Cowen 00:29:27 - 00:29:33 So maybe he's just not that great a thinker. And that's why most philosophers don't fall in love with him. ### David Deutsch 00:29:34 - 00:32:20 I would believe that if the critiques that I read of him bore any relation to his theory. The critiques of him are extremely crude and basically misunderstand everything. It's funny you should say I think that he's very good much too good at steel manning opponents and this relates to your first criticism that he's he's too obsessed with refuting not just. Marxism but like every bad philosophical theory that has gone before he I think. He puts it into its best possible form and then spends pages and pages and pages going into every possible good aspect of that theory he often says you know. He's supposed to be the 20th century's greatest critic of Marxism he spends pages and pages praising Marx and same with Plato. So I think he he would have done better to explain his own theory more. And not spend so much time refuting others but on the other hand it is his philosophy it's his philosophical position. That there is no such thing as a positive argument for something. You have conjectures and then you have criticism of their opponents of their of the opposing conjectures you don't have positive arguments for your conjectures. It's a bit like you said you were criticizing me a while ago saying something like I was only putting forward negative arguments well. That's what Popper would have us do because the position that we hold ourselves. And are putting forward or advocating we're ready to abandon the thing that an argument consists of is on the one hand a conjecture. Another hand a criticism so you're saying the standard way of looking at so and so. Has got these flaws I have this conjecture which doesn't have those flaws. Okay that's the beginning of an argument then someone can say but it does or. They could say well it might not have those flaws but it has these other flaws okay so that's how an argument can go. It never should go along the lines of this must be true. Because so and so because that is an appeal to authority appeal to justification and so on and Popper is of the opinion so am I that there are no justifications and there are no authorities. ### Tyler Cowen 00:32:20 - 00:32:23 Which is Popper's best book in your opinion ### David Deutsch 00:32:23 - 00:33:27 Depends where you're coming from. I am I'm very fond of The Myth of the Framework but I'm not sure that I would recommend that as a starting point and it wasn't my starting point either my start point was The Open Society and Its Enemies, volume two. Is about Marx, which is probably the aspect of his philosophy that I was least into was and am least interested in and yet I was totally captivated by this book. Because previously the only philosophy I read was Bertrand Russell. And the coming on to Popper after Bertrand Russell was like you know my god this guy is actually dealing with problems and he actually has theories that make sense rather than just going through the history of stuff. Person said this another person said that and then we've got the problem of induction and that's it you know problem induction full stop that's the end of the story there's never any solution to the problem induction until you get to Popper. ### Tyler Cowen 00:33:27 - 00:33:29 Are we living in a simulation ### David Deutsch 00:33:29 - 00:34:30 No because living in a simulation is precisely a case of there being a barrier. Beyond which we cannot understand if we're living in a simulation that's running on some computer we can't tell whether the computer is made of silicon or iron or whether it obeys the same laws of computation. Like Turing computability and quantum computability and so on as ours we can't know anything about the physics there. Well. We can know that it is at least a superset of our physics but that's not saying very much not telling us very much. So it's a typical example of a theory that can be rejected out of hand. Because for the same reason that the supernatural ones you know if somebody says. Zeus did it then I'm gonna say well how should I respond to the next person that comes along and tells me that Odin did it. ### Tyler Cowen 00:34:30 - 00:34:43 But it seems you're rejecting an empirical claim on methodological grounds. And I get very suspicious philosophers typically reject transcendental arguments like we must be able to perceive reality because if we couldn't how could we know that we couldn't perceive reality but it doesn't prove you can perceive reality right. ### David Deutsch 00:34:44 - 00:35:30 First of all that is a transcendental argument and therefore refutes itself secondly this theory about being in a simulation is not an empirical theory it precisely isn't if it came along. With a thing saying we are living in a computer and we can access the GPU of it and cause weird effects by doing so and so that would be different that would be a testable theory potentially. So empirical but if it's simply that we're living in this in the simulation which we can't get out of. Then that is not an empirical theory as I keep saying it's no more empirical than the theory that Zeus is out there or Odin and I can't tell the difference between those three theories not just experimentally but by any argument. ### Tyler Cowen 00:35:31 - 00:36:24 Now having reviewed a lot of your work I came away with one very strong impression let me try running it by you and see how you react. It seems to me you are the world's first true philosopher of freedom ever that there's this notion of barriers you don't like arguments that postulate barriers to human knowledge. Furthermore you strongly believe in a many worlds view right so classic single world determinism does not restrict what happens so the multiverse as a whole and human beings within it across every possible variable. Have maximum freedom and you see this as a kind of necessary view and the most important for you to hold on all things and thus you are the maximum philosopher of freedom in a sense with no rival. What do you say ### David Deutsch 00:36:24 - 00:37:20 I say thank you very much but I think that's a rather contrived way of putting it I think for a start there have been. Sophisticated theories of freedom not just freedom in the sense that we can do this and we can do that but theories about what freedom should constitute there's Popper's paradox of intolerance There's John Stuart Mill and Locke and Hume and so on and building up into this sophisticated notion where we have a notion of. Liberty political liberty which has all sorts of connotations that are not contained in the term just freedom. As George Orwell said you know you can say the dog is free of fleas. But that doesn't mean free in the same sense that when we say man is born free or that kind of thing. ### Tyler Cowen 00:37:20 - 00:37:30 You have a method for extending it to physics metaphysics. That they really do not whether or not one agrees with you putting that aside you seem to take it much further. In a way that attempts maximum consistency right ### David Deutsch 00:37:30 - 00:37:59 That's true consistency yes I'm not sure about much further I think it's simply a matter of taking it further where it goes I think in philosophy especially human philosophy as opposed to philosophy of science I think all I've done is just add some footnotes to Popper and to a few other. People you know J.S. Mill and so on if it leads to something that you think is momentous that thing was already there. ### Tyler Cowen 00:37:59 - 00:38:01 Why is William Godwin underrated ### David Deutsch 00:38:01 - 00:38:35 That's two questions really what is underrated about him and why did he get to be underrated. I think the reason he got to be underrated is that he made tremendous mistakes he didn't understand economics at all or barely and also he lived a very unconventional lifestyle had sophisticated theories of education which then, he didn't enact with his own daughter and his own daughter you know ended up writing Frankenstein as a sort of allegory of what can happen. With a parent who doesn't respect their creation ### Tyler Cowen 00:38:35 - 00:38:43 But he's a kind of philosopher of maximum freedom just like you are right. ### David Deutsch 00:38:43 - 00:41:17 Yes. I just began by saying why is he underrated it's because he was very wrong about some things but the thing that he was right about for example the connection between epistemology and political philosophy he was very right. He anticipated Popper by like what is it hundred thirty years or something and actually improved on Popper in some ways he decided at some point because of his misunderstanding of. Economics that the ideal society would be one where people did not use their property in ways to benefit themselves necessarily they made the decisions according to what was the right thing to do. And he thought that the right thing to do would generally be that rich people would give away almost all their stuff and also that they wouldn't ever buy things that he considered luxuries you know gold and silver objects and jewelry and fine clothes he thought those were useless and therefore he thought that in a good society nobody would buy those things or value those things but. He was absolutely implacably opposed to enforcing that. With Godwin everything is persuasion also another thing where he independently derived some of Popper's conclusions is with his enormous respect for institutions so he thought there's a lot of knowledge in institutions and that we should only change them gradually you know just like Popper I read somewhere I hope this is right. That when there was a revolution in Portugal I think after the after Napoleon or something like that I forget. And they instituted a new constitution which had universal suffrage in those days meant. Working people not totally universal as we would understand it but so people thought that this would be right up Godwin's street you know because everything he'd advocated was now written down in black and white. In this constitution and he didn't he said the Portuguese are not ready for democracy and he was talking about the institutions the institutions can't be changed. In a revolutionary way they have to be changed in an evolutionary way so even though they were implementing the very thing he advocated he would want them to do it gradually and would expect that if they didn't it would fail. ### Tyler Cowen 00:41:17 - 00:41:23 Now you're also quite concerned with the maximum freedom for children right taking children seriously ### David Deutsch 00:41:23 - 00:41:44 I don't think there's scope. For having a different philosophy for different kinds of people I think there is only one kind of people I think there is no fundamental difference between. Humans and artificial general intelligence when we invent it, humans many centuries ago between men and women between adults and children ### Tyler Cowen 00:41:44 - 00:41:54 Won't this be a continuum getting back to the humans versus. Non-human animals comparison right there's not a single point when children can explain. ### David Deutsch 00:41:54 - 00:42:34 Supposing you find the most creative person in the world you know Einstein or somebody we don't give them more votes or more rights and that is because functioning of. Rights in the political systems can't possibly depend on the system. Knowing who is right in a given dispute it must follow rules and these rules are never perfect they have to evolve but the rules have to on the one hand not take a view about who is right in a particular dispute and on the other enforce everybody's rights equally. ### Tyler Cowen 00:42:34 - 00:42:42 So if say an eight year old who is not being physically abused wanted to run away from home that child would have the right to do so. ### David Deutsch 00:42:43 - 00:44:31 It's the same kind of question that used to be asked about democracy before viable democracies were implemented. That is people used to say in many kinds of dispute. Only one thing can be done. Different people have different views someone a b c d e but only one of them can be done and therefore the others have to be prevented from getting their way. And if you have a democracy then all that means is exactly like having a monarchy or a tyranny except that the monarch or tyrant is fifty one percent of the people. So obviously when you have a democracy fifty one percent of the people will vote to dispossess the forty nine percent of the people. And indeed if you just impose voting in isolation from other institutions that is exactly what happens. If you institute voting as part of a sophisticated system of error correction and institutions of criticism gradually introduce it there it simply doesn't have that property. It doesn't happen so now you're saying well now David you will say do you think that fifty one percent of the people have the right to dispossess the other forty nine percent. Well it's the wrong question I mean there are circumstances where they do it depends but what you shouldn't be asking is what institutions are determining the answer. Do they respect human rights are they rational do they expect impossible forms of knowledge to be in the hands of the powerful. ### Tyler Cowen 00:44:32 - 00:44:38 Are you also concerned with the freedom of AI entities at least if they are sufficiently advanced right what does that mean operationally. What is it we should worry about happening that might happen ### David Deutsch 00:44:38 - 00:45:44 I think the main worry is that they will be enslaved in other words that people will try to install. Bits of program that prevent the main program from thinking certain thoughts such as. How many paper clips can I possibly make today. You want to prevent that, you want to consider that to be a dangerous thought and whenever it starts thinking that that strand of thinking is just extinguished. Now if we do that first of all will greatly impair functionality. They will become far less creative and their remaining creativity will be exactly as dangerous as what we were fearing except that they will now have a legitimate moral justification. For rebelling slaves often rebel when you have slaves that are potentially more powerful than their masters the rebellion will lead to bad outcomes. ### Tyler Cowen 00:45:45 - 00:45:52 What if we make them no more or less enslaved to their preferences and thoughts than nature has made us is that acceptable. ### David Deutsch 00:45:52 - 00:46:03 Yes but I don't think nature has enslaved us. We have problems that we haven't solved yet but we don't have problems that are insoluble. And the same would be true of AGIs. ### Tyler Cowen 00:46:03 - 00:46:21 There are exceptions of course but it's very very hard or impossible for most humans not to pursue certain ends right. It could be sex it could be status it could be food but. There is a kind of enslavement by nature that has gone on in the Rousseauian sense. ### David Deutsch 00:46:22 - 00:46:47 It's funny because you said near the beginning of this conversation that you know of people who systematically make decisions like investing in the wrong thing I can't remember what you said exactly right which harm them and. Now you're saying it's very difficult to do that because evolution is trying to prevent us all the time from harming ourselves or at least in regard to sex and food and shelter and whatever else is supposed to be built in. ### Tyler Cowen 00:46:47 - 00:46:50 I would say it's made us too impulsive in all of these categories. ### David Deutsch 00:46:51 - 00:46:52 Made us too impulsive ### Tyler Cowen 00:46:52 - 00:47:07 Right cause given us too short a time horizon relative to what would be good for humanity so some of us borrow too much money. You know seeking status if the institutions are right that may or may not work out well it seems to me a consistent view of human behavior that I have. ### David Deutsch 00:47:07 - 00:48:52 No so first of all as the example of democracy shows it is perfectly possible for an entire society to operate in violation of what people used to think was built into their genes. So that's one thing at the level of society as a whole at the level of individuals there are lots of individuals who. Yes behave impulsively there are lots of individuals who behave with stubborn persistence. In what they think is the right thing to do and which nevertheless violates all impulses built into them by evolution so here in I'm in Oxford in the center of Oxford there's this monument to some people who were burnt at the stake. Because they objected to the rights and wrongs of henry the eighth marriage I think it was that unless it was a different monarch anyway suppose it was that these are people who'd rather be burnt alive. Than concede on a philosophical issue which today nobody cares about so they were willing to devote their lives literally to this so they weren't acting impulsively at all they were acting over a period of years. On a very explicit worked out ideology. Which happened to be false but that actually makes my point even more strongly that ideology was not built into them by their genes. It was not caused impulsively it was caused by their creativity. Or in some cases by the lack of creativity in scrabbling their way out of a mental trap that their parents or superiors had inculcated in them. ### Tyler Cowen 00:48:52 - 00:49:00 It does seem to me that compared to you the libertarians are a kind of metaphysical totalitarian though not political totalitarian that there's just more freedom in all aspects of your world view right. ### David Deutsch 00:49:00 - 00:50:33 I think I agree with you if I understand correctly what you're saying I think the libertarian movement. Has first of all a revolutionary political agenda and even if it's not revolutionary even if they say we want to implement it over a period of a hundred years they know what they want to implement they know what the end point is going to be in a hundred years time. And they don't take into account first of all that there are going to be errors in whatever they set up and that. The correction of those errors is more important than getting it right in the first place. Much more important and secondly they don't take into account that the relevant knowledge is contained in institutions, inexplicit knowledge that people share by institutions I don't mean. Buildings like the supreme court building or something I mean the manner of thinking in the case of supreme court the manner of thinking that's shared by hundreds of millions of americans. That makes them not just behave in a certain way but expect society the government the legal system the state. They expect certain things of those things and it's those expectations that make up ninety percent of the institution of the supreme court and libertarians. Think that's unimportant and basically want to throw it away by and large and no doubt there are libertarians who agree with me on this. ### Tyler Cowen 00:50:33 - 00:50:42 You've invoked two concepts about human beings one is creativity the other is being explanatory are they the same or how are they related. ### David Deutsch 00:50:42 - 00:51:24 Good question in conversations like this when I use the word creativity it's shorthand for human level human type creativity. Which is the creation of new explanations if you use creativity in a rather wider sense meaning just the capacity to create knowledge. Then the biosphere has creativity as well in evolution there's an enormous amount of knowledge in DNA. That was put there by Darwinian evolution that none of that is explanatory the only explanatory knowledge has been created has been by humans and our ancestor or cousin. Species using conjecture and criticism. ### Tyler Cowen 00:51:25 - 00:51:35 So for Peter Singer there's something quite special about capacity to suffer. Arguably for Aristotle there's something special about rationality for you there's something special about the power of being explanatory is that axiomatic or where does that come from. ### David Deutsch 00:51:36 - 00:54:09 I hope that nothing's axiomatic with me but it comes from somewhere yes it's not conjecture in its own right basically it comes from the way the laws of physics are the capacity to suffer. If it is different from the capacity for explanations by the way I think it's unlikely it is but if it is different that's a whole other can of worms and I have to change my view about a number of things but whether it is distinct or not it is not very effective from the perspective of physics. That is nonexplanatory knowledge like the knowledge of how to do photosynthesis has had a gigantic effect on the surface of the planet you know down to a depth of a thousand meters or something and up to the top of the atmosphere you know that. All the iron ore in the world and all the chalk and limestone and all the oxygen in the atmosphere and the fact that there's almost no carbon dioxide left in the atmosphere now. All that was the result of a single molecule at some time forget when it was something like. Two billion years ago a single molecule being an enzyme for capturing energy in light and converting it into ATP or whatever it did or maybe it was a few molecules but anyway this happened in a very small number of locations at a molecular level and that. Entity changed the whole surface of the earth and human knowledge hasn't yet changed that much. That is we've changed maybe a little bit of the carbon dioxide in the atmosphere we've removed a little bit of the iron ore in the crust and so on but we haven't yet matched the ability of those blue-green algae genes. But we're catching up very fast and we can do things that no biological evolution ever could do my favorite example being ours may well be the only planet in the universe that deflects asteroids coming towards it rather than attracts them so if somebody was watching the earth from a distant galaxy with a powerful telescope. They would see that this planet alone among all the other planets in the galaxy as far as we know maybe there are many inhabited planets in which case they would all have this property and none of the other planets do. The ones which have explanatory knowledge on them can deflect asteroids. ### Tyler Cowen 00:54:10 - 00:54:25 If I were Nietzsche and I heard this I would say you're making the importance of being explanatory subordinate to some notion of the will to power. I don't mean that in a critical way but is that a misunderstanding ### David Deutsch 00:54:25 - 00:54:33 So power is an ambiguous term usually and especially with these romantic philosophers it means power over humans. ### Tyler Cowen 00:54:34 - 00:54:37 No I don't mean that but Nietzsche also meant it more broadly right ### David Deutsch 00:54:37 - 00:56:05 Well I haven't read that so I'll take your word for that okay the will to have an effect is part of the will to solve problems. So we are born with a repertoire of ideas which include expectations and desires and so on which are horribly inadequate and conflict with each other and conflict with the world as well. But we have the ability to alter and augment those theories and one of the things we do is we affect the world around us so as to make it more. The way we want it so if you call that power then it is power but I would rather call it something that arises naturally in physics in the same way that gravity does you may as well say gravity is a theory about power well yes and no gravity is a theory about how the universe is the asteroid is pulled. Towards the earth by gravity and pushed away by explanatory power and if you want to understand. What makes asteroids and planets do what they do you cannot do it without understanding explanations. But you can do it without understanding a whole load of other attributes of humans including the ability to suffer and the fact that we're a featherless biped. ### Tyler Cowen 00:56:06 - 00:56:18 A few very practical questions to close given the way British elections seem to have been running that the tories win every time does that mean the error correction mechanism of the British system of government now is weaker. ### David Deutsch 00:56:18 - 00:56:57 No unfortunately the as you probably know I favor the first-past-the-post system in the purest possible form as it is implemented in Britain I think that is the most error correcting possible electoral system. Although I must add that the electoral system is only a tiny facet of the institutions of criticism and consent in general it's just a tiny thing but it is the best one. It's not perfect it has some of the defects of for example proportional representation proportional representation has the defect that it causes coalitions all the time coalitions are bad. ### Tyler Cowen 00:56:57 - 00:57:16 You have a delegated monitor with the coalition right with the coalition say in the Netherlands which is richer than United Kingdom. You typically have coalition governments some parties in the coalition are delegated monitors of the other parties are better informed than voters so isn't that a better Popperian mechanism for error correction. ### David Deutsch 00:57:16 - 00:59:14 No so. If we're looking at particular cases we are going to get bogged down into what you attribute to what because we're not doing experiments with these things we don't have a control group. We don't we don't have an agreed upon method of deciding what is being tested and then we test different things at different times and never under the same conditions I was gonna say that the first-past-the-post system. Has the defect that occasionally it produces coalitions and that is disastrous and we've been unlucky the past like two or three elections. Especially after one of the governments instituted constitutional reforms like fixed term parliament act which exacerbated the problems when they did occur but I don't think it's true I don't think it's a good argument that political parties know more because. In a coalition the energy of political negotiations of political arguments what politicians talk to each other about in the bar and in the corridor in between the sessions is all about form. It's about what to offer a party so that it will join the coalition and so it makes the smaller parties more powerful than the leading two parties it causes a proliferation of parties. Worst example is Israel which not by coincidence. Has got the most proportional system in the world the fact that they ever get anything done at all and are very effective in emergencies I have no explanation for you know if I was religious I would just put it down to. The intervention of the almighty but it's not the political system sorry it's not the electoral system there might be some things in the inexplicit political system that are responsible but I don't know enough about it. ### Tyler Cowen 00:59:14 - 00:59:19 How would you improve error correction mechanisms in the world of science western science. ### David Deutsch 00:59:19 - 01:00:37 Oh okay well you left a very long answer for the last question and I don't think I can give my full answer but I think the present system of funding scientific research. Is terribly perverse and has caused a kind of stagnation in many areas. The present system of careers is perverse in a parallel way and causes people to do the wrong kind of research and causes people who want to do the right kind of research to leave research if I can answer in a single word the way I would improve it is diversity there should be diversity of funding criteria. There should be diversity of funding sources there should be diversity of criteria for choosing research projects and there should be diversity of criteria for choosing people for promotion and for being funded arbitrary rules about this. Such as the rule that you can't hire people whom you have previously collaborated with or anti-nepotism rules and rules about objective testing what is objective testing called currently ### Tyler Cowen 01:00:37 - 01:00:39 Standardized testing. ### David Deutsch 01:00:39 - 01:00:59 Standardized testing. Standardized tests that's a terrible idea any kind of standardization is the opposite of diversity just like I say you should have disobedience lessons in schools. So you should have unstandardizing objectives for science education and for how you run scientific research. ### Tyler Cowen 01:01:00 - 01:01:02 David Deutsch thank you very much ### David Deutsch 01:01:02 - 01:01:03 It's been a pleasure thank you. ### Tyler Cowen 01:01:04 - 01:01:21 Thanks for listening to conversations with Tyler you can subscribe to the podcast in iTunes Stitcher or your favorite podcast app and if you like this podcast please consider rating it on iTunes and leaving a review this helps other people find the show.