Joe Rogan Experience #1216 - Sir Roger Penrose

1. 0:00 – 15:00

   All right, here we…

   1. JRJoe Rogan0:02

      All right, here we go. Three... (clears throat) Boom, and we're live. How are you, sir?

   2. SPSir Roger Penrose0:09

      I'm fine, pretty good.

   3. JRJoe Rogan0:11

      Thank you for doing this. I appreciate it.

   4. SPSir Roger Penrose0:12

      That's fine. My pleasure.

   5. JRJoe Rogan0:14

      Who roped you into this?

   6. SPSir Roger Penrose0:16

      I think, I suppose James Tagg, probably. (laughs)

   7. JRJoe Rogan0:19

      (laughs) I, uh, am a big fan of your work. I've read much of your work. I've seen many of your interviews and videos online. And, uh, one of the things that I really wanted to talk to you about, that I find quite interesting is consciousness.

   8. SPSir Roger Penrose0:33

      Mm-hmm.

   9. JRJoe Rogan0:33

      And your belief that consciousness is not simply calculation, but that there's something more to it, and what, what you think this more could possibly be from a scientific perspective, which is unusual 'cause a lot of people have some theories about consciousness, but they're usually crazy people like myself.

   10. SPSir Roger Penrose0:53

       (laughs) Well, I mean, we're all conscious, and so we may have theories about it.

   11. JRJoe Rogan0:58

       Yeah.

   12. SPSir Roger Penrose0:59

       But, uh, no, the ideas came by somewhat roundabout route. Uh, I, I went to Cambridge to do graduate work. It was mathematics. I was working on pure mathematical subjects, algebra, geometry. But I thought, you know, "We got three years, I'll spend some of the time going to other talks that might be interesting." So I went to three talks particularly, which had a big influence on me. One was a talk by Hermann Bondi. It was on general relativity, cosmology. Wonderful talk with very sort of animated presentation he had. And then there was a talk by Paul Dirac, one of the founders of quantum mechanics. And his talk... well, his complete... wonderful talk, too. It was... Wonderful lectures as well, but in a completely different style. He was very quiet and precise in what he said and everything. And in the very first lecture, he was talking about the superposition principle in quantum mechanics. So if you have a particle and it could be in one spot, or it could be in another spot, then you have all sorts of states where it can be in both places at once. And he... That's sort of strange, but you got to get used to that idea. And he illustrated with this piece, a piece of chalk, and I think he broke it in two to illustrate it could be in one spot or in the other. And my mind sort of wandered at that point. I don't know what I was thinking about, but I wasn't concentrating. And about a few minutes later, he'd finished his description, his explanation, and I had some vague memory of something about energy, but I didn't understand what he said and I've been totally mystified by this ever since. So I, I suppose if I'd heard what he said, he would have said something to calm me down and, and make you sort of accept it in one way or another. But as it was, it seemed to me this was a, a major issue. How on earth do you have things that don't behave according to what quantum mechanic says? Like cricket balls and baseballs and things like that. Anyway, that's two of the talks. The other course was a course by a man called Steane, who talked on mathematical logic and he explained things like Godel's theorem and Turing machines, Turing machines being the mathematical notion upon which modern computers are based, or all computers basically. And, uh... (clears throat) Uh, the thing about Godel's theorem... You see, I'd heard... I used to have a colleague when I was an undergraduate, Ian Percival, who also became a scientist later on, and we talked about, uh, logic and, you know, how you could make these kind of mathematical systems which worked out logic. And I'd heard about this Godel's theorem, which seemed to say that there were things in mathematics that you just couldn't prove, and I didn't like that idea. But I... when I heard the... when I went to this course by Steane, and he explained what it really says. And what it says is, suppose you've got a method of proving things in mathematics, and when I say things, I mean things with numbers. The one famous example is Fermat's Last Theorem. Uh, there's the Goldbach conjecture, which isn't yet proved, that every even number bigger than two is the sum of two prime numbers. That's the sort of example of the thing. It's just sort of mathematical things about numbers, which you can see what they mean, uh, but it may be very difficult to see whether it's true or untrue. But the idea i- often is in mathematics, you've got a system of methods of proof, and the key thing about these methods of proof is that you can have a computer check whether you've done it right. So you... these rules, you know, they could be adding A and B, it's the same as B and A and things like that.

   13. JRJoe Rogan4:54

       Mm-hmm.

   14. SPSir Roger Penrose4:54

       And you, um... if you give... you, you say to the computer, say, "Here is a theorem," like Goldbach conjecture, and you see whether it can be proved and you say, "Maybe I've got a proof, and this follows these steps." And you give it to the computer and it says, "Yep, you've done it right. It's true." Or maybe it will say, "You've done it right and it's not true," or it may not say anything. It might just go on forever. But these are the sort of outcomes, and the point about it is that if you believe that these procedures do give you a proof, in other words, that if the algorithm says, "Yeah, it's true," then you believe that it is true because you've understood all the rules. You looked at the first one and said, "Yeah, that's okay." You looked at the second one and said, "Um, oh, yeah, I see. Okay, that's great." And you go all the way down, and as long as you're convinced all those rules work, then if it says yes, that's something you believe. Okay. Now, what Godel shows as he constructs a very specific sentence, a statement which is a number thing, like, like the Fermat's Last Theorem or something, a thing about numbers which-What he shows is if you trust this algorithm for proving mathematical things, then you can see by the way it's constructed that it's true. But you can also see by the way it's constructed that it cannot be proved by this procedure. Now this was amazing to me, because it tells me that, okay, you cannot f- formalize your understanding in, in a, a scheme which you can put on a computer. The, you see, this statement which Godel comes up with is something you can see on the basis of the same understanding that allows you to trust the rules that it's true, but that it's not actually derivable by the rules. It, you see it's true by virtue of your belief in the rules. And this, to me, was amazing. And I thought, "Golly, you know, what's understanding? What does it mean? Is it something following rules? Is this an algorithm?" Well, this more or less says it's not an algorithm, because whatever it was, there will be something that you can still see as true even though you don't get it through the algorithm that you had in the first place. So this was a, oh, there are a lot of subtleties about this too, which people argue about endlessly, but it was pretty convincing to me that this shows that we don't think when we understand something, th- that what's going on in our heads is not an algorithm, it's not following rules. It's something else. It's something that requires our conscious appreciation of what we are thinking about, um, thinking as a conscious thing and understanding is a conscious activity. So I formed the view that conscious activities, whatever they are, not just that kind of thing, but, you know, um, playing music or, or falling in love or whatever these things might be, are not computations. There's something else going on. And then I thought because I, you know, I'm... Like to think of myself as a scientist and I think that what's going in, in our heads is according to the laws of physics, and these laws of physics, um, pretty good. They seem to work well in the outside world, and so I believe that the laws that work in our heads are the same as those laws. So I began to think about it. Well, what about Newton's mechanics? Well, you could put that on a computer. What about Einstein's special relativity? You could do that. What about Maxwell's wonderful equations, which tell you how elec- electricity and magnetism operate, and light, and radio waves, and all these things, that all follows this beautiful set of equations that Maxwell produced. You can put that on a computer. Okay, you may have to worry about approximations, and, you know, these depend on continuous numbers rather than discrete things, but I didn't think, "That's the answer." Then I thought, what about general relativity, Einstein's theory of gravity with curved space and all that. Well, y- y- we're familiar now with LIGO, this detector which has detected black holes spiraling into each other from distant galaxy, and how do we know that those signals are black holes spi-... well, because of calculations. People have put this thing on an algorithm, and you know what those signals look like. So Einstein's general relativity, sure, you can put that in a comp- on a computer. What about quantum mechanics? Well, there's the famous equation of Schrodinger which tells you how a quantum state evolves. You could put that on a computer too. It's difficult in many ways, there's many more parameters you've got to worry about, but it's just as computable as these other things. Well, you see, I then remembered Dirac's lecture, you see, and how it is that these things that work in the quantum world don't seem to work a- at the level of classical big things, and it all depends on this process of what's called measurement in quantum mechanics. And the measurement process is something you learn how to do, but it's not the Schrodinger equation. It's something else. And Schrodinger himself was very intrigued by this fact, that his own equation gives you nonsense, and y- y- the famous Schrodinger's cat where he produces a situation in which the cat would be dead and alive at the same time, he produced that in an example simply to demonstrate that, roughly speaking, his equation gives you nonsense under these circumstances. So there's something else, and the something else goes beyond our current quantum mechanics, and it tells you what happens when the quantum state makes a decision between, well, it doesn't follow the Schrodinger equation, it's one thing or the other. Now, everybody knows that who does quantum mechanics, but they think, "Oh, it's what's called making a measurement and you're allowed to do something different," but that didn't make sense to me. And so I had the view that, okay, there is a big gap in our understanding, and if there's something in the world which isn't something you could put on a computer, that's where it is. So the view, I've held that for a long time, and, uh, that there's something non-computable, something beyond computation involved in our understandings of things. So that's a view I held for ages. I didn't do much with it, I just held the view until... Now, I think there was a, a radio talk between Marvin Minsky and Edward Fredkin, and they were explaining about what computers can do, and they were talking about, okay, you have a computer, two computers talking to each other over there, and you walk up the room. In the time you've walked up the room to the computers, they have comput- commun- communicated with each other more thoughts than the human race ever has done, you see. And I thought, "Well, I see where you're coming from, but I don't think that's what's happening." In, in human communication, human understanding is something different from what computers do, and consciousness is the key thing. Consciousness is something different from computation. So I've held that view, but then when I heard this talk by Minsky and, um, and Fredkin, I thought, "Well, I had ideas of writing a book sometime in the long time in the future when I'm retired." This was some while back, I say. (laughs) And I thought, "Well, may-... this gives it a focus."And so I wrote this book called The Emperor's New Mind, which was supposed to be saying, "Well, you know, we, um... uh, l- everybody seems to be thinking one thing, but, uh, the little kid notices that" (laughs) -

   15. JRJoe Rogan12:46

       (laughs)

   16. SPSir Roger Penrose12:46

       "that the emperor doesn't have any clothes." So it was the, uh, that theme of that story which was the basis of the book. So, I say, "Okay, maybe lots of people think that what we're doing is computing, but if you stand back and you say, 'Well, no, there's something else going on.'" So that was the basis of my thoughts about consciousness, but I wrote this book thinking that by the time I got to the end of the book... You see, it was, it was all about, mostly about physics and mathematics and things like that, but I was really aiming for this thing about what's going on in conscious thinking. And I thought, "Well, I'll learn a bit about neurophysiology and so on, and by the time I get to the end of the book, I'll know pretty well wh- what it could be." I didn't. (laughs) I got to the end of the book, and I just sort of tapered off, rather, with something a little bit unbelievable, and that was the end. Now you see, I'd hoped that this book would stimulate young people to get interested in science and that sort of thing, that mathematics, and that was fine. And when the book was published, I didn't get letters from y- young kids. I got letters from old retired people who... the ones who'd (laughs) had the time to read my book. Okay, well, that was a little disappointing, but okay, I'm glad the old retired people liked my book. But the other thing was, I got a letter from Stuart Hameroff and this letter said, more or less, "I think you don't appreciate that there's something else going on." Not neurons. I mean, the neurons, I could see, you couldn't isolate the quantum effects and the, the, the... you get the... what's it called? The environmental decoherence would happen, and you'd get no way of keeping the quantum state to the level that you need in this picture, so I realized I didn't have it. But Stuart Hameroff pointed out to me these little things called microtubules, and he'd built up a theory that microtubules were absolutely fundamental to consciousness. He had his own reasons for believing that. I'd never heard of them at that time, but then I checked up... You know, I get lots of letters from people who maybe don't make sense sometimes, the letters. And this one, I thought, "Well, is this another one?" (laughs) But then I realized these microtubules are there, and they

2. 15:00 – 30:00

   And microtubules, they're inside…

   1. SPSir Roger Penrose15:00

      look like just the kind of thing that could well be supporting the kind of level of quantum mechanics up to a level where you, you could expect the, the quantum state to sort of collapse. That's the terminology people use in quantum mechanics.

   2. JRJoe Rogan15:14

      And microtubules, they're inside brain neurons?

   3. SPSir Roger Penrose15:17

      They are indeed.

   4. JRJoe Rogan15:18

      And this is a recent discovery? Fairly recent?

   5. SPSir Roger Penrose15:19

      No! We've been going on for... They're actually in lots of cells, you see. People often complain, "Oh, they're in your liver too, not just-"

   6. JRJoe Rogan15:25

      Mm-hmm.

   7. SPSir Roger Penrose15:25

      "... your brain, so-"

   8. JRJoe Rogan15:26

      Right.

   9. SPSir Roger Penrose15:26

      "... why isn't your liver conscious?" And all that. But this has to do with the organization of them and the nature of them, the particular kind of microtubules, how they're- how they're arranged, which is different in the brain.

   10. JRJoe Rogan15:36

       How, well, how does it vary in the brain compared to other cells?

   11. SPSir Roger Penrose15:39

       I think one big difference, although I'm not... Stuart emphasizes it so much, there are two kinds of microtubules. They're the ones called the A-lattice and the B-lattice. And the A-lattice ones are the very symmetrical ones, they're tubes and, and they look the same all the way around. They've got a very beautiful arrangement of these proteins called tubulin, and they make a very nice arrangement, which is connected with Fibonacci numbers and things like that. So, they look a bit like fir cones, but they're all parallel, they're not... they don't, um, taper off. But, um, uh, the thing is, in the brain, I think most microtubules are probably what are called B-lattice ones, and they don't have so much symmetry. They've got a l- a, a sort of seam down the... one side, and they're very important in transporting su- substances around cells and so on. And microtubules, all sorts of things, they don't just do what, what Stuart and I think they may be doing in the brain. So, the idea is that, in the brain, they're organized differently and they... probably the ones that are important are the A-lattice ones, which are the very symmetrical ones. And f- for a long time, people couldn't see the difference in... um, because they look very similar. Um, and they may well be the ones that happen to be in pyramidal cells as a particular kind of cell. So, you know, one of the things int- interested me a lot is how it is that not all parts of the brain are the same in this respect. You see, you've got the cerebrum, this is the part at the top and, you know, divided down the middle and that... when you see brains, that's what you normally see with the convolutions in, in, in it. But right underneath and at the back, there's a thing called the cerebellum, which more... looks more like a, like a ball of wool or something, and the cerebellum, I don't... I... there may still be argument about this, but it seems to be that it's completely unconscious, and it has comparable number of neurons, far more connections between neurons than the cerebrum, and it's what takes control when... maybe when you're driving your car and you're thinking about something else, and you, you don't... you're not thinking what you're doing, because it's unconscious, and the unconscious control... You know, a pianist who's very expert and moves the fingers around and plays a note with her little finger, that pianist doesn't think, "Well, I gotta move that muscle this way and this bone that way," and so on. And it's, it's all controlled unconsciously, and a lot of this unconscious control is done somewhere else in the cerebellum when you, when you get really skilled. So, uh, it seemed to me, okay, you've got different kinds of structures, different... And it could well be that these pyramidal cells, which have a particular organization of microtubules, are the ones that... where the consciousness is really a- coming...... coming to light mainly. I don't know. There's a lot which is, which is not known about this, controversial and all sorts of things. But the cerebellum seems to be different and organized differently. So it's not just how many neurons, how many connections are there, because there are more in the cerebellum. So it's not that, it's something else.

   12. JRJoe Rogan18:41

       And do they know this from observing the brain through FMRI or something like that during particular activities, like how-

   13. SPSir Roger Penrose18:47

       Uh, I don't know. I would imagine partly just examining it when... from dead people and looking at brains and trying to estimate how many neurons there are in it.

   14. JRJoe Rogan18:56

       Right. But how would they know what... which part, portions or act during these particular activities-

   15. SPSir Roger Penrose18:58

       Oh, which is conscious. Well, I, I don't know that they do know that well, I guess. (laughs)

   16. JRJoe Rogan19:03

       Hmm.

   17. SPSir Roger Penrose19:04

       But the co-... the cerebellum, there is a bit of an argument about that, uh, th- whether it's completely unconscious or not, but it seems that actions that's, that are carried out by the cerebellum, you, you don't... you're not aware of what you're doing.

   18. JRJoe Rogan19:17

       Hmm.

   19. SPSir Roger Penrose19:18

       But I mean, s- you know, if you're the tennis player who has to think very carefully about where the, you know, what, where to tilt the ball. Now, the control of what you're doing, so overall control, is probably done with the cerebrum. But the cerebellum is controlling the detailed motions, how the fingers move and all that kind of thing, and then you make sure that if you... the player thinks they're gonna hit the ball down, down the line there, and then the, the rest is done under the con- uh, control of an unconscious procedure. I may, I, I may be simplifying, but that's also-

   20. JRJoe Rogan19:51

       I, I understand what you're saying.

   21. SPSir Roger Penrose19:52

       Yes.

   22. JRJoe Rogan19:52

       So you're saying that th- there's... we don't totally understand, but w- we know that there's different parts of the brain that are responsible for different activities.

   23. SPSir Roger Penrose20:00

       Yes.

   24. JRJoe Rogan20:00

       And some activities don't seem to be conscious.

   25. SPSir Roger Penrose20:03

       Yes. Yes. I mean, I think it's probably the case... no, I'm, I maybe... I don't know. I, I shouldn't make a statement when I don't really know. But certainly, there are lots of different parts of the cerebrum which may be, which may be not conscious too.

   26. JRJoe Rogan20:19

       Mm-hmm.

   27. SPSir Roger Penrose20:19

       So I'm not saying that the whole thing is capable of being conscious. It's they seem to be differences in different parts.

   28. JRJoe Rogan20:26

       But are you convinced that microtubules are responsible for consciousness or it's, uh, a primary theory?

   29. SPSir Roger Penrose20:34

       (laughs) I think they're the, one of the best candidates. Uh, you see, I don't think it's only microtu-... I don't know.

   30. JRJoe Rogan20:41

       Mm-hmm.
3. 30:00 – 45:00

   (laughs) …

   1. SPSir Roger Penrose30:00

      uh, I think I heard the description or I read it. I, I think I read it, about there were some experiments on testing the intelligence of octopuses or... And they had a, a little thing. They, they had to pull a chain and then open a door and get food out. And this octopus was thinking, "Uh, I'm getting fed up with this thing." And so he yanked the chain and it came right off, and then it rose to the top and started squirting all the people in their white coats. (laughs)

   2. JRJoe Rogan30:23

      (laughs)

   3. SPSir Roger Penrose30:23

      So (laughs) I thought that was pretty good, you know. There's something else going on than just-

   4. JRJoe Rogan30:28

      There is something going on.

   5. SPSir Roger Penrose30:29

      Yeah. Absolutely.

   6. JRJoe Rogan30:30

      Now, when you, uh, uh, if you weren't pressed for, to, to, to put, uh, to figure this out in some sort of a, uh, a paper that you had to display in front of scientists. If you were...

   7. SPSir Roger Penrose30:41

      (laughs)

   8. JRJoe Rogan30:41

      If you were like, you're trying to figure out, like, what do you think it is? Like, what d- what do you think consciousness is?

   9. SPSir Roger Penrose30:49

      Well, you see, I, I mean, to... It's going too far to think, you know, I know what the, what the answer is or anything like that.

   10. JRJoe Rogan30:54

       Of course.

   11. SPSir Roger Penrose30:55

       I just, I just think that this-... issue of having some kind of quantum state which preserves itself up to a certain level, and the microtubules at least suggested something where you could isolate them from the outside and the symmetry of these things is important, and there are other structures. It's, I suspect it's not just microtubules. I suspect ... There are these, um, thing called clathrins. These are, are molecules which inhabit the synapses, and, um, you can ... And the thing about these ones is that they're incredibly symmetrical. They're like a, a soccer ball, you know? They ... You have these pentagons and hexagons and at each vertex, you've got a protein, it's called a triscalion, and they join themselves along the edges of the, of the pattern of the soccer ball. Okay, but it's just a, it's just a, a, a, a substance. I mean, it's made of these proteins, and what are they doing hanging around in the synapses? I don't know, but they ... The symmetry has a key role. There's a thing called the Jahn-Teller effect in quantum mechanics which tells you that when you have a, a, a s- highly symmetrical structure like that, then there can be a big gap between the lowest energy level and the next one, and there can be information in this lowest energy level which can be s- shielded from the higher energy levels. So this is a sort of suggestion that some kind of quantum phenomenon is going on in a serious way, uh, and there's a lot to understand there. I mean, synapses themselves are kind of strange things, you might think. If you were going to build a brain, why don't you just solder the wires together at the connections, you see?

   12. JRJoe Rogan32:36

       (laughs)

   13. SPSir Roger Penrose32:36

       What are you doing having this thing with all the chemist- chemicals transferring this information from one side to the other?

   14. JRJoe Rogan32:42

       Yeah.

   15. SPSir Roger Penrose32:42

       I don't know, but it's something very needed for, by the system, and it's all tied up with these clathrins there and, and cytoskeleton structures, which microtubules are one of the main constituents, so you see ... I don't know. There's a lot to learn, I'm sure.

   16. JRJoe Rogan32:59

       So it seems like there's, uh, a bunch of different factors. There's the biological understanding of the brain itself.

   17. SPSir Roger Penrose33:04

       Yeah.

   18. JRJoe Rogan33:04

       And then there's the understanding of the, the actual s- nature of cells and of reality itself.

   19. SPSir Roger Penrose33:11

       Yes, yeah.

   20. JRJoe Rogan33:11

       That this is being more illuminated by science with every new discovery.

   21. SPSir Roger Penrose33:16

       Yeah.

   22. JRJoe Rogan33:16

       You know, we're getting a better understanding, deeper and deeper-

   23. SPSir Roger Penrose33:19

       Yeah.

   24. JRJoe Rogan33:19

       ... as to the, the very nature of matter and of, of the, the, of these structures themselves.

   25. SPSir Roger Penrose33:24

       I, I think it is getting deep into the, into the way the physical world operates and things that we don't understand about it just yet. Yes. I mean, the biology is one side of it, and I ... You know, coming as an outsider, I get struck by certain things. I mean, quite familiar with the fact that the right side of the cerebrum controls the left hand and the left hand, the right hand.

   26. JRJoe Rogan33:45

       Mm-hmm.

   27. SPSir Roger Penrose33:46

       But then you look at this, and it's not just that. What about the soles of your feet? Right at the top. What about your eyes? The, the signals right at the back.

   28. JRJoe Rogan33:54

       Hmm.

   29. SPSir Roger Penrose33:55

       You'd think this is the most ridiculous construction. You, you've gone to the worst possible place.

   30. JRJoe Rogan34:00

       Yes.
4. 45:00 – 1:00:00

   Mm-hmm. …

   1. SPSir Roger Penrose45:00

      originally I guess Chandrasekhar, an Indian scientist, when he was not quite 20 I think, I can't remember if it was 19 or 20, and he was, uh, going to England to study physics, astronomy and so on. And he worked on this problem about what holds white dwarfs apart. These are these very massive stars, the companion of Sirius. Sirius is a white dwarf. And, uh, he was doing calculations to find out, uh, whether they, uh, what... The interior is a very particularly struc- structure of matter, and he came to the conclusions if they had a bigger mass than a certain amount, which is about, uh, a bit less than w- one and a half times the sun's mass, they wouldn't be able to hold themselves apart, and so they would collapse. And he didn't speculate on what had happened, he just went on his list. I think it was some very modest comment he made, is when, uh, we are left speculating on possibilities (laughs) or something.

   2. JRJoe Rogan45:57

      Mm-hmm.

   3. SPSir Roger Penrose45:57

      But then that was in the 1930s, I guess, around about 1930, and much later just before the war, um, Second World War, 1939, well I say a bit later I guess, 19, um, 39, there was a paper by Oppenheimer of atomic bomb fame and Snyder which is a student of his, Hartland Snyder, and they produced a model which was a, well, a solution of the Einstein equations which describes a- a cloud of dust which collapses and becomes what we now call a black hole. So this was the first clear picture of collapse to a black hole. Now, in their picture they made two huge assumptions. Well, one of them is dust, the material, that means it didn't have any pressure and so you could imagine when it gets close to itself it might push away if it had pressure on it in any way, but this was just dust. That was one thing, but more important that their model was exactly symmetrical, so it was just spherically symmetrical, all the matter falling in, the dust particles would be focused right into the central point. And so it's not so hard to believe that you get a singularity where the density goes infinite, the curvatures go infinite, and your equations go crazy. So at that point when the dust reaches the middle point, okay, it's not so surprising because it's a very contrived situation. So I think a lot of people thought, "Well, perhaps we shouldn't take it seriously." They, I think they weren't sure. But then there was a paper by two Russians called Kalatni- Lifshitz and Kalatnikov, and they seemed to have proved that you didn't get singularities in the general case, that somehow it would swirl around and swish out again, you see? So that was a possibility. And then there was this discovery I think in 1962 when Maarten Schmidt, a Dutch astronomer, okay, Dutch-American I think he, where he was living there at the time, I don't remember, but he observed what became what we call the, the first quasar. So this was an object which was irradiating an awful amount of energy, far more than a- an entire galaxy, but it seemed to be a very small thing. It couldn't be much bigger than the size of the solar system, if even that big, because it, variations in brightness indicated that they had hit the speed of light could... Size of it had to be comparable with, uh, the speed at which the variations in- in- in, um, in brightness came about. So it seemed to be an object that was enormously energetic, producing more energy than a whole galaxy and varying with such a degree that it must be fairly small, and this raised the question of whether it was small enough to be what we now call a black hole. In other words, its, um... There's a thing called the Schwarzschild radius...... Schwarzschild was the man who first discovered the solutions of Einstein's equations, which described this spherical body. But he didn't extrapolate it inwards to what's called this horizon. We call it a horizon now, it used to be called the Schwarzschild singularity and people began to realize that it wasn't really a singularity, it's more something you could imagine falling through. I guess it was Lemaître who first made clear... that clear, but not many people paid attention. But that was the idea of a black hole and it looked then is that these quasars could be having some black hole in the middle of them and I remember John Wheeler, who was at Princeton then, very distinguished scientist, and he got very worried about these things and he talked to me and he got worried about it and, "Do we believe? Is there a singularity in the middle? Do we believe? Lifshitz and Kleinkraft that they sort of swirl around and bounce out, what are we supposed to think?" So I started thinking about this problem and since... at that time, well, you see either people... when you want to solve the Einstein equations, either you make a lot of assumptions and it's a symmetrical... li- like the Oppenheimer-Schneider model, you assume it's got very special properties and then you can maybe solve the equations, but only very, very special cases and the computers weren't powerful enough to tell you very much about what happened. So I started thinking about this problem and realizing that I'd have to think about it in a different way and so I used ideas which involve ideas from topology and things like that to show that there had to be a singularity in the middle, provided that the collapse had reached a certain point of no return. I guess, uh, to get some idea of... I don't know, it's just not too misleading (laughs) , there's a- a mathematical theorem called the- the Hairy Dog Theorem (laughs) .

   4. JRJoe Rogan50:48

      Hairy Dog Theorem?

   5. SPSir Roger Penrose50:49

      Yes. I mean, that's just a jocular terminology.

   6. JRJoe Rogan50:53

      Right.

   7. SPSir Roger Penrose50:53

      But you think of, uh, something which is topologically a sphere, that means, you see, i- you imagine a dog shape, but you could sort of move it around with a piece of plasticine until it looked like a sphere. It doesn't have holes in it. Okay, forget about his digestive system, you see? You're thinking about the surface outside.

   8. JRJoe Rogan51:10

      Mm-hmm.

   9. SPSir Roger Penrose51:11

      And then you're... uh, the problem is you try to comb the hair on the dog all the way around and the theorem says there's got to be somewhere where the hair doesn't lie flat. A- a- and you try it on a sphere, there's got to be a point where- where the hair makes a kind of singular point. So it's a bit like that. You have no idea where the singularity is but you know from general topological reasons that there's got to be one somewhere and that was the sort of argument that- that I produced and, uh, I guess a lot of people had a little bit of trouble because they'd never seen this kind of argument (laughs) and a lot of people picked up on it, in particular Stephen Hawking and, uh, i- it became, for a while, a l- uh, many people were working on it. I guess it's not so popular now because probably we've run out of theorems (laughs) .

   10. JRJoe Rogan52:00

       Uh, uh, uh, the idea of a singularity, like, uh, is... when you see something like a- a quasar or th- the- the center of a- a galaxy-

   11. SPSir Roger Penrose52:12

       Mm-hmm.

   12. JRJoe Rogan52:13

       ... um, and we- we're talking about a black hole, when you say a singularity, what- what exactly are you- do you mean by that?

   13. SPSir Roger Penrose52:20

       Well, the normal expectation is that you have a place, like in the middle of the Oppenheimer-Schneider dust cloud, that a point there where the density becomes infinite and so the curvature of spacetime becomes infinite. So you have a place where the equations run away and they go to infinity and you say, "Well, something's gone wrong." But maybe initially it was in these very symmetrical cases, but- but you could show by these indirect arguments that somewhere something's got to go wrong. You can't continue the equations of Einstein and they get stuck-

   14. JRJoe Rogan52:58

       Right.

   15. SPSir Roger Penrose52:58

       ... to the place where they go infinite or... What in detail happens, the theorems don't tell you, they just say that something goes wrong and that's what we call a singularity.

   16. JRJoe Rogan53:08

       And if a black hole is larger or smaller, the singularity remains constant?

   17. SPSir Roger Penrose53:13

       It- it remains in- in there, it's-

   18. JRJoe Rogan53:15

       Remains in there, but it's not measurable in terms of its actual size?

   19. SPSir Roger Penrose53:18

       Yeah, I don't know whether you can measure its size very well 'cause the size... that's (laughs) , that's an intriguing question. You might say the size has gone to zero-

   20. JRJoe Rogan53:27

       Right.

   21. SPSir Roger Penrose53:27

       ... but it could be quite com- complicated and irregular, not like the original Oppenheimer-Schneider one which saw just a... Even then, a point is the wrong point of view, but let's not go into that (laughs) .

   22. JRJoe Rogan53:38

       Mm-hmm.

   23. SPSir Roger Penrose53:39

       No, it- it... there is something about the structure of these things you can say. They're not all the same, no.

   24. JRJoe Rogan53:44

       The- the singularities are not all the same, but the black holes are not all the same, right?

   25. SPSir Roger Penrose53:47

       They're not all the same, but they... that's one of the strange things about black holes, is that if you let them settle down, they're not all the same to begin with, but there are not many different things they can settle into. They can have rotation, they can have a certain mass th- and the mass translates into the size of the diameter of the hole, and you've also got rotation, so they can rotate. And these are... Schwarzschild found the non-rotating ones and it was Roy Kerr, an Australian, who first produced the solution for a rotating black hole.

   26. JRJoe Rogan54:21

       Rotating?

   27. SPSir Roger Penrose54:22

       Yes, a rotating one. But then, you see, the remarkable thing is that's what they settle down to. So there are good theorems which tell you that a general black hole, which should be very complicated, fairly rapidly will settle down and become one of these Kerr solutions, a rotating black hole.

   28. JRJoe Rogan54:38

       I remember when I first saw that documentary and I saw the- when they were discussing the- the shape of these galaxies and that the center of it had this super massive black hole that was slowly devouring the galaxy-

   29. SPSir Roger Penrose54:50

       Yeah. Yeah.

   30. JRJoe Rogan54:50

       ... I mean, it's... (sighs) it- it is an unbelievably beautiful yet simultaneously terrifying idea is that there's this-
5. 1:00:00 – 1:15:00

   Mm-hmm. …

   1. SPSir Roger Penrose1:00:00

      expands and expands and expands, it gets colder than the black holes and so those black holes get, become the hotting f- hottest things around and so they radiate away very, very slowly this Hawking radiation. And that carries energy and so they shrink, and they shrink, and they shrink, and finally they disappear with a pop. When I say a pop it's probably a pretty big explosion but, but, um, n- n- n- not that big from a cosmological, astrophysical scale. So they disappear. Well, it may have been pretty boring when you're sitting around waiting for the black hole to go pop, but afterwards that's really boring. So this was (laughs) a picture I thought of, being rather depressed by it, thinking that's, that's our, the fate, you see?

   2. JRJoe Rogan1:00:43

      Mm-hmm.

   3. SPSir Roger Penrose1:00:43

      The fate of all the interesting things happening, ultimate fate, is this unbelievably boring final state. Okay, this is an emotional argument but l- give me a bit of leeway. (laughs)

   4. JRJoe Rogan1:00:54

      Okay.

   5. SPSir Roger Penrose1:00:54

      So I began to think, "Well, it's not gonna be us who are going to be bored because we're not gonna be around. The, the main things that'll be around will be photons."... and it's pretty hard to borrow a photon-

   6. JRJoe Rogan1:01:07

      (laughs)

   7. SPSir Roger Penrose1:01:08

      ... for two very good reasons. One is, it probably doesn't have conscious experience, there's no way that's sure, so... But the other is more the science point, that the t- they don't measure time 'cause a photon has no mass, it travels at the speed of light, and c- w- the way relativity works, it means that clocks stop, if you like. So if it had experiences, it would... the moment of its creation would be one moment and the next moment would be infinity. And so they just zip out to infinity without noticing a thing. Now you see, I'd been doing work on this kind of thing, thinking more about gravitational radiation and how you measure its energy and things like that, and it was a very useful picture to squash down infinity. A useful thing to think about here, if you've seen these pictures by the Dutch artist MC Escher-

   8. JRJoe Rogan1:01:57

      Mm-hmm, yes.

   9. SPSir Roger Penrose1:01:58

      ... and there are those which are called Circle Limits, and there's a very famous one with angels and devils interlocking, and they get all crowded up onto the edge. Now, what you've gotta think about is that this is a kind of geometry called hyperbolic geometry, and the angels and devils live in that geometry. And the ones right close to the edge think they're the same size and same shape as the ones in the middle. Oh, you got it.

   10. JRJoe Rogan1:02:21

       There it is right there.

   11. SPSir Roger Penrose1:02:21

       Great.

   12. JRJoe Rogan1:02:22

       Yeah.

   13. SPSir Roger Penrose1:02:23

       And so, the, the idea is that if you look at it from the angels and devils point of view, that's infinity, that boundary.

   14. JRJoe Rogan1:02:32

       Mm-hmm.

   15. SPSir Roger Penrose1:02:33

       But from our point of view, we can look at it and we have what's called a conformal map, that picture is a conformal map. What that means is that little shapes are quite consistently drawn, but they can be big or small, and you don't care about whether they're big or they're small, as long as small shapes are accurate, or angles, if you like, are correctly drawn. So it's what's called a conformal map, and that conformal map describes infinity. Now you can do the same thing to, to the universe. When I say do it, um, you can imagine it. (laughs)

   16. JRJoe Rogan1:03:07

       Mm-hmm.

   17. SPSir Roger Penrose1:03:07

       Where this remote future, you can squash it down, just like in the Escher picture, to a finite boundary. And as far as the things with no mass, they don't have a way of measuring how big or small it is. The Maxwell equations don't know the scales, they don't care. It's... they work just as well for small as for big, and you can stretch it in some place and squash it somewhere else, as long as the stretching and squashing is isotropic, so just as much one way as the other way, which means more or less that you keep what are called the light cones there. Let's not go into details here, but it means that, that if you have things without mass, and most particularly the photons, then that boundary is just like anywhere else, and the photons go zipping up to it, and so you might think they've gotta have somewhere to go. Okay, well, that's a... you don't have to think that, but that was the point of view I had-

   18. JRJoe Rogan1:03:58

       Mm-hmm.

   19. SPSir Roger Penrose1:03:58

       ... that the photons need to... need somewhere to enter, in a way, but then where does it go? But then there's the other picture, which is the opposite end, there's the Big Bang. Now you can do a similar sort of trick there, which is stretching it out and making it into a boundary. And that can be done, too. I, I played around with these ideas for a long time, and the standard cosmology models, you can do it with. But the more complicated cosmology models, you might have one which is very complicated Big Bang, the general ones don't look like that at all. So you need a condition which tells you that the Big Bang was a very special kind that it was. It's all tied up with this thing called the second law of thermodynamics, and this all ties together with physics in a way which perhaps we don't have time to talk about. (laughs) But it seemed to me a really good idea to have the condition on the Big Bang that you could continue it in the same way. I should say the idea of doing this was a former student of mine, Paul Todd, who was a colleague of mine, and he used this as continu- a c- conformal continuation as a w- as a nice way of saying what the condition is on the Big Bang to give you what you want. But that's a huge condition, but it... nevertheless, it's what starts our universe off in, in a, a, a very special state, which, uh, is what we live off, in a way. It's the second law of thermodynamics needs that to, to get going. Anyway, l- uh, I don't know if you wanna worry about that. But anyway, the point was that it looks as though it's a good condition on the Big Bang that it also should be conformally like a boundary, which, if you had no mass, you wouldn't notice it. Okay, you've got particles with mass running around near the Big Bang, but as you get closer and closer and closer, the energy goes up, the temperature goes zooning, zooming up. They're zipping around at such a speed that the energy of their motion is much bigger than the E equals MC squared mass, Einstein's mass. E- e- the energy in, in the mass is a certain amount, but when they get so hot, you can forget about the mass.

   20. JRJoe Rogan1:06:10

       Mm-hmm.

   21. SPSir Roger Penrose1:06:10

       So they, like photons, behave like, uh, particles without mass, and so they're just interested in the conformal geometry. So the crazy idea I had, not just only you stretch out the Big Bang and you squash down the infinity, but maybe our Big Bang was a squashed-down infinity of a previous eon. So I'm saying our eon began with a Big Bang, ended up with this exponential expansion. There was another one before us, there will be another one after us, there was another one before that, and so on.

   22. JRJoe Rogan1:06:46

       So it's an infinite cycle of Big Bangs-

   23. SPSir Roger Penrose1:06:48

       That's the picture.

   24. JRJoe Rogan1:06:49

       ... and constant expansion to the point where there's no more energy, and then somehow or another a big bang comes out of that again.

   25. SPSir Roger Penrose1:06:54

       Yes, that's right. Well, that's the tricky part that people have trouble with, yes. (laughs)

   26. JRJoe Rogan1:06:57

       It's universally accepted that the Big Bang was an event. There's no-

   27. SPSir Roger Penrose1:07:01

       Pretty well universally.

   28. JRJoe Rogan1:07:02

       ... conflicting theories that are attractive?

   29. SPSir Roger Penrose1:07:07

       ... I would say nothing terribly popular. There are certain ideas which say you can continue into the, before the big bang. Paul Steinhardt and-

   30. JRJoe Rogan1:07:16

       And what do they think that was?
6. 1:15:00 – 1:21:13

   Hmm. …

   1. SPSir Roger Penrose1:15:00

      I have a different view, which is that the theory is not quite, quite right, right, and that, um, there is something which makes the, the collapse into a physical process, and, uh, the... There's, there's only one world. Now, the other many worlds view, which is... comes from a different reason, and that is that there he se- there seem to be various accidents, um, in... Well, maybe one of them being that the neutron is just slightly more massive than the proton. That's one. There are lots of other accidents we see that if they were a little different, then life as we know it couldn't happen.

   2. JRJoe Rogan1:15:38

      Hmm.

   3. SPSir Roger Penrose1:15:39

      And so how do you explain this? Well, some people say, "Well, all these universes with different values of these constants all coexist. It's just we only see the one that we're in because the numbers come out right for us." So that's what's called an anthropic argument.

   4. JRJoe Rogan1:15:55

      Hmm.

   5. SPSir Roger Penrose1:15:56

      Okay. I can see the argument. I don't like it much. It's sort of... I think we need a better explanation for why the numbers are what we see and so on. But that's... That, that one makes more sense to me than the other one. So, so I think one kind... maybe has to take that seriously, but it's certainly not the view I'm presenting here with this picture.

   6. JRJoe Rogan1:16:18

      It's... For someone like me, it's so interesting to know that there's still a considerable amount of speculation.

   7. SPSir Roger Penrose1:16:25

      Yes. Oh, yeah. Well, it's, it's... There's a lot of speculation, but a lot of it is pretty off the wall, and a lot of people-

   8. JRJoe Rogan1:16:34

      Hmm.

   9. SPSir Roger Penrose1:16:34

      ... think mine are off the wall, you see-

   10. JRJoe Rogan1:16:36

       (laughs) Right. Well, who's-

   11. SPSir Roger Penrose1:16:37

       ... and they think, "Oh-"

   12. JRJoe Rogan1:16:37

       ... who's to say?

   13. SPSir Roger Penrose1:16:38

       "... okay, I'm, I'm, I'm an old man now, and so it's okay, you know, did thing, decent things in the past, but you shouldn't trust his views now," you see.

   14. JRJoe Rogan1:16:47

       (laughs)

   15. SPSir Roger Penrose1:16:47

       So I, I guess that's what people think. I don't know. But you see, if it was just me, I could understand that, you know?

   16. JRJoe Rogan1:16:52

       Right.

   17. SPSir Roger Penrose1:16:52

       But I've got these poli- And then I've got an Armenian colleague who's done things on this too, and, uh, it can't be that we're all, all off the rails, I think (laughs) .

   18. JRJoe Rogan1:17:02

       No, it can't be.

   19. SPSir Roger Penrose1:17:02

       It's, it's something out there, and now with the Hawking points, there's something people can really go out and look for, and if they don't see them, there's something funny going on somewhere. If they do see them, there's something else going funny on, which, which they'll have to think of another explanation, unless it's my explanation. They'll have to think of a, a different view from the current inflation view, which is in real trouble with these observations, as far as I can see.

   20. JRJoe Rogan1:17:25

       Do you anticipate in any foreseeable time in the future, uh, a better understanding of dark matter and dark energy or, uh, uh, perhaps a better definition of what those things are?

   21. SPSir Roger Penrose1:17:35

       Um, yeah. Well, you see, I think... My, my own current view is that dark energy, as it's called, is the cosmological constant. Now, that's not an explanation, if you like, 'cause why is it go-

   22. JRJoe Rogan1:17:46

       Right.

   23. SPSir Roger Penrose1:17:46

       Why has it got the value it has? Why is it there at all? And there are certainly questions about that which I agree with. Dark matter, I didn't go into this, but in this scheme of mine, it has to be there. When I say "it," I mean that if you want the equations to make sense, which cross over from our remote future to the Big Bang of the next eon, you have to have a creation of a dominant new material which is scalar, and as I said, it doesn't spin, it's just ordinary particles, and that they only interact gravitationally. And that's what we see. But the theory, uh, that I'm putting forward would make these things very massive. They're about what's called the Planck mass. I don't know exactly, 'cause there's some freedom in this, something like the Prank- Planck mass, which people describe as, uh, the mass of a flea's eye. Don't quite know why they make it that. (laughs)

   24. JRJoe Rogan1:18:46

       Whoa.

   25. SPSir Roger Penrose1:18:46

       But that's about 10 to the minus 5 grams, so you're looking at a, a 100,000th of a gram. So it's, it's sort of a, an appreciable size. It's not, you know, it's not like basic particles in physics.

   26. JRJoe Rogan1:18:59

       It's measurable.

   27. SPSir Roger Penrose1:19:00

       It's the sort of measurable thing you could imagine you, you, you could get h- get hold of in some way. But that's huge for, for a fundamental particle.

   28. JRJoe Rogan1:19:09

       Hmm.

   29. SPSir Roger Penrose1:19:09

       So it's a, it's a wild idea from that point of view. But also, they should decay, and they should decay into gravitational signals which maybe could be seen by LIGO, maybe have been seen by LIGO and thrown in the rubbish bin because they'd be different types of signals from what people would expect. I wouldn't like to put my money...... anywhere there, but I'm liking, hoping that these dark matter particles are the ones that come f- from the theory that, that I'm putting forward. So that would be another consequence of this particular point of view.

   30. JRJoe Rogan1:19:47

       And they've observed, correct me if I'm wrong, entire galaxies that they believe are... that consist of dark matter.

Episode duration: 1:36:52