WEBVTT - Ep110 "Is consciousness related to quantum physics?" (with Roger Penrose and Stuart Hameroff) 0:00:05.040 --> 0:00:09.280 Why do we have the experience of being conscious? Can 0:00:09.320 --> 0:00:12.840 you build consciousness just by putting together lots of neurons 0:00:12.840 --> 0:00:17.320 in the right way, or might there be deeper principles 0:00:17.360 --> 0:00:21.160 at work. Could quantum physics have something to do with 0:00:21.200 --> 0:00:25.600 the brain and specifically with consciousness. Is it possible that 0:00:25.680 --> 0:00:30.280 consciousness is actually something that predates biology and there's a 0:00:30.360 --> 0:00:33.320 sense in which biology evolved to take. 0:00:33.200 --> 0:00:34.120 Advantage of it. 0:00:34.280 --> 0:00:37.000 And what are the right ways to make new theories 0:00:37.000 --> 0:00:41.640 in neuroscience when we don't know the answers. 0:00:42.720 --> 0:00:45.000 Welcome to Inner Cosmos with me David Eagelman. 0:00:45.159 --> 0:00:48.000 I'm a neuroscientist and author at Stanford and in these 0:00:48.040 --> 0:00:52.120 episodes we sail deeply into our three pound universe to 0:00:52.280 --> 0:01:11.000 uncover some of the most surprising aspects of our lives. 0:01:12.120 --> 0:01:17.160 Today's episode is about consciousness and quantum mechanics and the 0:01:17.319 --> 0:01:21.600 question of whether there could be even possibly. 0:01:21.440 --> 0:01:23.000 Any connection between them. 0:01:23.560 --> 0:01:25.560 So to get at this, I'll be talking today with 0:01:25.920 --> 0:01:30.360 Roger Penrose, mathematical physicist and polymath and winner of the 0:01:30.400 --> 0:01:34.640 twenty twenty Nobel Prize in Physics, and also Stuart Hammeroff, 0:01:34.680 --> 0:01:38.840 an anesthesiologist who has collaborated with Penrose for many years 0:01:38.880 --> 0:01:42.200 on a theory. Before we dive into those interviews, I 0:01:42.280 --> 0:01:44.640 want to set the table by saying that what we're 0:01:44.640 --> 0:01:47.800 going to talk about today are speculative ideas, and many 0:01:47.880 --> 0:01:50.520 neuroscientists don't even like to go near them. 0:01:50.840 --> 0:01:53.960 But the fact is that despite the thousands. 0:01:53.440 --> 0:01:59.200 Of neuroscience journals and textbooks and laboratories, there are still fundamental, 0:01:59.360 --> 0:02:02.640 basic questions that we don't know the answer to. And 0:02:02.640 --> 0:02:06.360 one of the most fundamental is the question of consciousness. 0:02:06.400 --> 0:02:11.080 Why does anything feel like something? In other words, imagine 0:02:11.320 --> 0:02:14.080 that you built a little toy out of pulleys and 0:02:14.160 --> 0:02:15.280 levers and switches. 0:02:15.840 --> 0:02:18.000 Would you say that it is conscious? 0:02:18.240 --> 0:02:22.600 Presumably you wouldn't now double your little toy in size 0:02:22.639 --> 0:02:25.960 with new levers and switches and pulleys. Is it conscious? 0:02:26.000 --> 0:02:26.240 Now? 0:02:26.880 --> 0:02:30.240 There's no particular it's theoretical reason to think. So now 0:02:30.320 --> 0:02:33.200 keep adding to it. Put on another pulley, in another lever, 0:02:33.320 --> 0:02:36.519 and another little door, and attach a wheel, and keep 0:02:36.560 --> 0:02:39.680 doing this until you fill a room and then a stadium. 0:02:40.240 --> 0:02:42.880 Do you have any reason to assume that it becomes 0:02:43.360 --> 0:02:48.480 conscious and has internal experience just because it's more and 0:02:48.480 --> 0:02:52.680 more complex. If you now remove a pulley, does it 0:02:53.000 --> 0:02:56.920 feel pain. And if you put a little molecular detector 0:02:56.960 --> 0:02:59.760 on it such that it can recognize molecules of different 0:02:59.760 --> 0:03:05.440 shit apes, does it have a different experience like displeasure 0:03:05.520 --> 0:03:09.520 for some shapes and pleasure for other shapes, And where 0:03:09.639 --> 0:03:13.920 is that happening. I certainly wouldn't think that your giant 0:03:13.960 --> 0:03:16.440 toy is conscious, or at least let me say that, 0:03:16.480 --> 0:03:20.240 I have no theoretical reason to believe that it suddenly 0:03:20.320 --> 0:03:26.760 experiences pain or hunger or longing or pleasure, because it's 0:03:26.840 --> 0:03:30.560 just pieces and parts. So this is a fundamental question 0:03:30.600 --> 0:03:34.720 about the brain. We look at your eighty six billion neurons, 0:03:34.880 --> 0:03:38.280 which are generally thought of, especially now in this era 0:03:38.400 --> 0:03:42.040 of AI, as being units that are popping either on 0:03:42.200 --> 0:03:44.600 or off one or zero. And so it's not clear 0:03:44.600 --> 0:03:48.160 to any of us in neuroscience why we have private 0:03:48.360 --> 0:03:51.840 subjective experience. And this is true whether you have eighty 0:03:51.880 --> 0:03:54.880 six neurons or eighty six billion or eighty six gajillion 0:03:54.960 --> 0:03:58.280 of them. Why do these little electrical signals and chemical 0:03:58.320 --> 0:04:03.160 releases give us the the experience of eating a lemon, 0:04:03.360 --> 0:04:07.040 or the pleasure of an orgasm, or the pain of 0:04:07.120 --> 0:04:12.600 stubbing your toe. Now, we don't know the answer. But 0:04:12.680 --> 0:04:16.960 here's a speculation that some people have put forward. Could consciousness, 0:04:17.360 --> 0:04:22.760 the most intimate, subjective, elusive feature of our existence, have 0:04:23.000 --> 0:04:26.760 something to do with quantum physics. Now, this is not 0:04:26.800 --> 0:04:30.040 a mainstream idea in neuroscience. You're not going to find 0:04:30.080 --> 0:04:34.920 it in the standard textbooks most cognitive scientists, if asked 0:04:35.040 --> 0:04:40.040 to explain consciousness, we'll talk about neurons and synapses and 0:04:40.120 --> 0:04:44.840 the emergent properties of complex systems. The language will be 0:04:45.200 --> 0:04:50.719 biological and electrochemical and computational. But a few scientists have 0:04:50.800 --> 0:04:54.559 suggested a hypothesis that there's something deeper going on, something 0:04:54.680 --> 0:04:57.320 much stranger, and that's what we're going to explore today. 0:04:58.120 --> 0:05:02.599 I'm not presenting an argument that auto mechanics does explain consciousness, 0:05:02.600 --> 0:05:06.000 but it's worth understanding why some serious minds are entertaining 0:05:06.080 --> 0:05:10.080 the hypothesis. So we'll begin with Roger Penrose, who is 0:05:10.360 --> 0:05:14.000 perhaps an unexpected figure in this conversation because he's not 0:05:14.040 --> 0:05:18.400 a neuroscientist. He's a mathematical physicist. He's done so many 0:05:18.400 --> 0:05:22.159 amazing things in his career. He worked with Stephen Hawking 0:05:22.320 --> 0:05:25.360 on black hole singularities, or he might know him for 0:05:25.440 --> 0:05:29.279 his geometrical shapes called Penrose tiles. And you certainly know 0:05:29.360 --> 0:05:31.640 him because in twenty twenty he won the Nobel Prize 0:05:31.640 --> 0:05:36.200 in physics for showing that black holes result naturally from 0:05:36.240 --> 0:05:39.400 Einstein's general theory of relativity. And by the way, he's 0:05:39.440 --> 0:05:43.640 also the one who mathematically described black holes in detail, 0:05:43.839 --> 0:05:48.520 including their singularity where all known laws of nature dissolve. 0:05:48.680 --> 0:05:49.560 But especially in. 0:05:49.520 --> 0:05:53.159 The nineteen eighties and nineties, Roger Penrose turned his attention 0:05:53.640 --> 0:05:56.320 toward the brain, not because he wanted to build a 0:05:56.320 --> 0:05:59.679 better theory about cognition, but because he had a concern 0:05:59.680 --> 0:06:05.680 about out algorithms. Penrose felt that consciousness just can't be 0:06:05.800 --> 0:06:09.320 explained by any rule based system. He pointed to an 0:06:09.320 --> 0:06:13.640 idea called Girdle's incompleteness theorem, which said, look, there are 0:06:13.760 --> 0:06:16.640 mathematical truths that we can see to be true, but 0:06:16.720 --> 0:06:21.000 they can't be proven within mathematics. In other words, there 0:06:21.000 --> 0:06:23.520 are many systems where we can see things to be true, 0:06:23.520 --> 0:06:26.520 but the system itself can't prove them. You need to 0:06:26.560 --> 0:06:30.400 somehow step outside of the system. Now, to Penrose, this 0:06:30.520 --> 0:06:35.159 was a sign that human understanding operates in a way 0:06:35.600 --> 0:06:40.719 that transcends computation. In other words, he said, brains aren't 0:06:40.800 --> 0:06:44.680 just computers, and if they're not just computers, then the 0:06:44.720 --> 0:06:49.039 mystery of consciousness might demand a different kind of physics. 0:06:49.400 --> 0:06:52.920 So he wrote a very interesting book called The Emperor's 0:06:53.080 --> 0:06:57.760 New Mind, which asserted that the brain can't just be 0:06:57.880 --> 0:07:01.320 a computer. So in your Book's New Mind, which I 0:07:01.400 --> 0:07:05.120 read as a young person and really loved, so you 0:07:05.560 --> 0:07:09.440 argue that consciousness can't be explained by algorithms. 0:07:10.080 --> 0:07:11.840 So help us to understand that. 0:07:12.240 --> 0:07:14.640 But it really means, you see, an algorithm is just 0:07:14.640 --> 0:07:17.840 the sort of technical word for a computer program. I 0:07:17.840 --> 0:07:20.360 feel like maybe people use that term. It just means 0:07:20.400 --> 0:07:24.520 that you have a rule which is a computational rule. 0:07:25.080 --> 0:07:28.679 Right, And why what made you feel that consciousness can't 0:07:28.720 --> 0:07:30.360 be explained by algorithms? 0:07:30.600 --> 0:07:33.400 Well, it goes back to the Girdle the lecture that 0:07:33.520 --> 0:07:38.080 Stein gave about Girdles theorem. And I realized that you see, 0:07:38.080 --> 0:07:42.960 if you see mathematical proof, you could have a set 0:07:42.960 --> 0:07:48.360 of rules, axioms and rules of procedure. These are of 0:07:48.520 --> 0:07:50.560 a nature that you could put them on a computer. 0:07:51.080 --> 0:07:56.400 You think there are forms of human insight that fundamentally 0:07:56.400 --> 0:07:59.800 cannot be replicated by algorithms. 0:08:00.480 --> 0:08:01.480 Is that that's correct. 0:08:01.720 --> 0:08:03.840 Okay, yes, absolutely right. 0:08:03.680 --> 0:08:06.160 Okay, great, and so and so that made you think 0:08:06.160 --> 0:08:10.600 that maybe this mystery of consciousness needed to be taken 0:08:10.720 --> 0:08:16.680 seriously by physicists and mathematicians. So, yes, So how did 0:08:16.760 --> 0:08:19.440 you how did you start addressing this? 0:08:20.080 --> 0:08:21.960 I was trying to think about the laws of physics 0:08:23.240 --> 0:08:28.000 that we sort of understand, and some of them are 0:08:28.160 --> 0:08:32.280 very powerful. Well, even you turn in mechanics explains an 0:08:32.280 --> 0:08:38.000 awful lot and science general theory of relativity explains a 0:08:38.000 --> 0:08:42.440 lot more, and it's more difficult to apply things, but 0:08:42.480 --> 0:08:45.440 it's still computational. What about quantum mechanics? 0:08:45.640 --> 0:08:47.360 Now, before we go further, I just want to give 0:08:47.400 --> 0:08:51.120 a reminder about what quantum physics is. It's the branch 0:08:51.120 --> 0:08:54.720 of physics that describes the behavior of matter and energy 0:08:54.840 --> 0:08:58.479 at the smallest possible scales, at the level of atoms 0:08:58.600 --> 0:09:03.880 and subatomic particles, and down there the world behaves nothing 0:09:04.000 --> 0:09:07.439 like what we're used to. Particles can be in more 0:09:07.520 --> 0:09:10.800 than one place at once. This is what's known as superposition. 0:09:11.080 --> 0:09:16.600 Particles can become mysteriously linked across space in what's called entanglement. 0:09:17.160 --> 0:09:19.559 And the most bizarre feature of all is that the 0:09:19.600 --> 0:09:24.240 mere act of measuring a system seems to affect its outcome. 0:09:24.400 --> 0:09:27.600 This is what's called the observer effect. In our current 0:09:27.679 --> 0:09:31.760 understanding of quantum mechanics, the story is that until a 0:09:31.880 --> 0:09:36.680 particle is observed, its properties don't exist in a definite way. 0:09:36.720 --> 0:09:38.760 They exist only in probabilities. 0:09:39.160 --> 0:09:42.560 In other words, a quantum particle doesn't have a precise 0:09:42.640 --> 0:09:46.200 location until you look at it. Until that moment, it's 0:09:46.559 --> 0:09:51.200 smeared across a range of possibilities, and then those possibilities 0:09:51.679 --> 0:09:55.720 collapse to one outcome when you observe. Now, this isn't 0:09:55.760 --> 0:09:59.120 just a metaphor. This general idea has been tested and 0:09:59.320 --> 0:10:02.679 confirmed for over a century, and it's built into the 0:10:02.720 --> 0:10:06.800 fabric of our technology. Quantum mechanics is the science that 0:10:07.040 --> 0:10:10.880 allows the transistors in your cell phone, and the lasers 0:10:10.880 --> 0:10:14.439 at the grocery store scanners and the GPS in your car. 0:10:14.840 --> 0:10:18.520 Quantum mechanics is real, and it's very countereteitive, and it 0:10:18.559 --> 0:10:21.199 seems to tell us that at the heart of reality 0:10:21.640 --> 0:10:26.640 is a kind of indeterminacy, a fuzziness that only collapses 0:10:26.679 --> 0:10:31.160 into certainty when it's observed. So think of it roughly 0:10:31.200 --> 0:10:33.800 this way. You toss a coin in the air and 0:10:33.920 --> 0:10:37.040 while it's spinning. It's not heads or tails. It's sort 0:10:37.080 --> 0:10:39.560 of like it's both at once, but the instant you 0:10:39.800 --> 0:10:44.560 catch it and look, it becomes just one heads or tails. 0:10:45.040 --> 0:10:48.640 That moment of catching it is like the wave function collapsing. 0:10:48.800 --> 0:10:50.679 Now here's the thing. In quantum mechanics. 0:10:50.720 --> 0:10:53.320 There's no way to predict what the coin's going to be, 0:10:53.480 --> 0:10:59.160 heads or tails, and so that non computable strangeness, that's 0:10:59.200 --> 0:11:04.520 what Penrose was interested in. He wondered, what if that indeterminacy, 0:11:04.559 --> 0:11:09.120 that collapse of possibilities into one real outcome, wasn't just 0:11:09.240 --> 0:11:13.120 a physical process but also has to do with a 0:11:13.200 --> 0:11:16.360 mental one. In other words, what if the flicker of 0:11:16.600 --> 0:11:20.680 consciousness is related in some way to the collapse of 0:11:20.720 --> 0:11:41.280 the quantum wave function. So back to Penrose talking about 0:11:41.320 --> 0:11:45.600 his search for something non computable and getting interested in 0:11:45.640 --> 0:11:46.559 the collapse. 0:11:46.960 --> 0:11:49.319 What about quantum mechanics? Then I thought, wow, I was 0:11:49.360 --> 0:11:51.800 shruding no equation, that has no problem about putting that 0:11:51.880 --> 0:11:55.640 on there. Maybe lots of parameters involved, it's make it tricky. Well, 0:11:55.840 --> 0:11:58.360 that's a well determined determined It is a good question. 0:12:00.080 --> 0:12:03.439 Roading equation doesn't give you what happens in the world. 0:12:03.760 --> 0:12:06.680 Why doesn't it give you what happens. Schrodering himself was 0:12:06.800 --> 0:12:10.920 very keen on explaining these things and his well known cat. 0:12:11.360 --> 0:12:14.640 He was making this is an absurdity. To have a 0:12:14.679 --> 0:12:16.720 cat which is dead and alive at the same time 0:12:17.080 --> 0:12:20.679 is a nonsense. This is point of what he was 0:12:20.720 --> 0:12:23.280 trying to make. He was saying, this is an absurdity. 0:12:24.000 --> 0:12:27.480 His equation he was trying to say. He was saying, 0:12:27.840 --> 0:12:32.080 roughly speaking, my equation does not describe reality. There is 0:12:32.120 --> 0:12:36.320 something more. And this something more is what we tend 0:12:36.400 --> 0:12:38.960 to call the collapse of the wave function. You're a 0:12:39.000 --> 0:12:42.480 wave function drugs along and behaves according to the Schroding 0:12:42.600 --> 0:12:47.240 equation very reliably and honestly, and then from now time 0:12:47.280 --> 0:12:49.760 to time it says, whoops, I'm going to do something else, 0:12:50.559 --> 0:12:54.240 and then it becomes probabilistic, and it's all hidden in 0:12:54.280 --> 0:12:58.160 all sorts of man and manical schemes. 0:12:58.360 --> 0:13:04.200 So you mean is that classical computation can't explain consciousness, 0:13:04.679 --> 0:13:07.800 and so the question is then what can? And this 0:13:07.840 --> 0:13:11.760 is where you make the fascinating proposal that quantum mechanics, 0:13:11.760 --> 0:13:15.760 and specifically the collapse of the wave function, might be 0:13:15.880 --> 0:13:17.640 involved in consciousness. 0:13:17.880 --> 0:13:20.160 See people say sometimes I'm just not say, well, here's 0:13:20.160 --> 0:13:22.319 the problem, and here's a problem. So they're the same thing. 0:13:22.600 --> 0:13:25.920 It's not that it's that we need something which is 0:13:26.000 --> 0:13:28.880 not a computable part of physics. What is it in 0:13:28.960 --> 0:13:32.160 the physics that we know it would not be possible 0:13:32.160 --> 0:13:34.760 to put on a computer. Well, you see, if the 0:13:34.760 --> 0:13:38.360 collapse of the wave function is purely random, then you 0:13:38.559 --> 0:13:42.040 could put it on a computer source off. And it's 0:13:42.080 --> 0:13:46.560 not perhaps really random, it's something very subtle, and you 0:13:46.720 --> 0:13:50.000 need that for the collapse of the wave function. And 0:13:50.320 --> 0:13:53.559 the story has developed in other ways beyond what I had. 0:13:53.559 --> 0:13:55.679 Then you see, this was the beginning of the story, 0:13:55.679 --> 0:13:58.200 and you're asking me about the beginning. The beginning was 0:13:58.240 --> 0:14:00.839 the story. It was a little bit in the sense 0:14:00.920 --> 0:14:03.400 that I didn't know really much about what to do. 0:14:04.000 --> 0:14:08.079 I could see that in according to my new point, 0:14:08.360 --> 0:14:12.360 the collapse of the wave function had to be a 0:14:12.440 --> 0:14:18.439 major part of the physics which is responsible for evoking consciousness. 0:14:18.559 --> 0:14:21.640 So to summarize where we are, Roger felt certain that 0:14:21.680 --> 0:14:27.120 consciousness couldn't be explained just by classical computation. Again, most 0:14:27.120 --> 0:14:30.000 of quantum mechanics you can easily model on a computer, 0:14:30.280 --> 0:14:33.600 like the evolution of the Schrodinger wave function, but there's 0:14:33.640 --> 0:14:37.040 something very weird about the collapse. That's the part you 0:14:37.080 --> 0:14:41.120 can't compute. So Roger felt he was onto something interesting there. 0:14:41.280 --> 0:14:43.920 So he sat down and wrote The Emperor's New Mind, 0:14:44.160 --> 0:14:46.760 and the title, as you might guess, was a reference 0:14:46.800 --> 0:14:51.080 to the story of the Emperor's New Clothes. The idea 0:14:51.160 --> 0:14:55.880 being that everyone is assuming we can explain consciousness by 0:14:56.120 --> 0:14:59.600 putting together enough neurons, but in fact, in his view, 0:14:59.640 --> 0:15:04.520 the burr is naked consciousness possibly can't be explained by 0:15:04.680 --> 0:15:07.400 just a bunch of neurons. So I asked Roger what 0:15:07.560 --> 0:15:10.960 happened just after he published the book In nineteen eighty nine, 0:15:11.080 --> 0:15:11.680 I wrote. 0:15:11.440 --> 0:15:14.840 My book Them Prisoner Mind and hoping some young people 0:15:14.920 --> 0:15:17.360 might be stimulating, and only got old retired people. I 0:15:17.440 --> 0:15:19.160 thought I'd done lo It was sort of a fairly 0:15:19.240 --> 0:15:22.600 reasonable job as an ignoramus, but not too bad at 0:15:22.600 --> 0:15:27.600 a job of trying to learn the main features of neurophysiology. 0:15:27.720 --> 0:15:30.280 So Roger started studying up on the brain, really as 0:15:30.320 --> 0:15:32.800 a side gig to his mathematical physics career. But the 0:15:32.840 --> 0:15:35.239 more he looked at it, he thought that maybe the 0:15:35.280 --> 0:15:38.040 macro level at which we were able to study. 0:15:38.080 --> 0:15:41.040 The brain wasn't really revealing its secrets. 0:15:41.240 --> 0:15:46.520 And I would say that it has a genuine, deep purpose, 0:15:47.960 --> 0:15:51.960 and that purpose is not clearly revealed in the structures. 0:15:52.040 --> 0:15:55.560 But it's not something which is obviously like a computer. 0:15:56.240 --> 0:15:58.360 Something else going on. But I didn't know what was 0:15:58.360 --> 0:16:00.480 going on. I had no real idea by the time 0:16:00.520 --> 0:16:02.000 I got to the end of my own presuming but 0:16:02.160 --> 0:16:05.080 I just I might. I could have stopped writing in 0:16:05.160 --> 0:16:06.880 this point, and I said, well, that's I've written so 0:16:06.960 --> 0:16:07.480 much so far. 0:16:07.560 --> 0:16:08.320 I better go on. 0:16:09.080 --> 0:16:11.120 And so I'm more or less sort of some idea 0:16:11.120 --> 0:16:14.160 which I didn't really believe. I tried to think of 0:16:14.200 --> 0:16:16.360 something that might be non computable, you see. 0:16:16.480 --> 0:16:19.160 So that's where things were for Rogers' idea. 0:16:19.280 --> 0:16:22.560 He suspected there must be some kind of quantum effects 0:16:22.560 --> 0:16:24.560 in the brain, but he didn't know where to look. 0:16:24.800 --> 0:16:27.280 But at the same time, in America, there was a 0:16:27.320 --> 0:16:32.680 young antesthesiologist named Stuart Hammeroff who was interested in consciousness. 0:16:32.720 --> 0:16:35.600 And I got interested in consciousness, and I went to 0:16:35.640 --> 0:16:39.560 med school and was interested in neurology, neurosurgery, psychiatry. But 0:16:39.600 --> 0:16:43.280 I didn't like those lifestyles, particularly what they got to do. 0:16:43.320 --> 0:16:45.640 They didn't actually get to do the surgency, but the 0:16:45.680 --> 0:16:49.320 neurologists in particularly didn't have much to do. And I 0:16:49.360 --> 0:16:53.000 took a research elective over summer in a cancer lab 0:16:53.040 --> 0:16:55.160 and studied my toasters. I figured just try something different, 0:16:55.600 --> 0:16:58.960 and so we uh studying cell division. And as you know, 0:16:59.040 --> 0:17:02.760 the cell divide, the chromosomes are separated by these spindles, 0:17:02.760 --> 0:17:03.920 which are microtubules. 0:17:04.160 --> 0:17:05.400 That's Stuart hammer Off. 0:17:05.720 --> 0:17:08.880 And while everyone in that lab was interested in the chromosomes, 0:17:08.880 --> 0:17:13.440 where the genes are, he found himself interested in the microtubules. Now, 0:17:13.480 --> 0:17:17.120 what are microtubules. The starting point here is that all 0:17:17.160 --> 0:17:19.760 the cells in the brain, like neurons and glial cells, 0:17:20.080 --> 0:17:24.080 are not empty. Inside every single brain cell is a 0:17:24.280 --> 0:17:27.760 bustling inner world. You've got all kinds of structures that 0:17:27.840 --> 0:17:31.719 help the cell keep its shape and transport materials around. 0:17:31.920 --> 0:17:36.880 And among these structures are microtubules, which are tiny hollow tubes. 0:17:37.080 --> 0:17:40.520 They're part of the cells skeleton. Sometimes people think of 0:17:40.560 --> 0:17:44.240 these like the tracks that guide packages through a warehouse. 0:17:44.800 --> 0:17:47.960 Now these are very very tiny. Each microtubule is about 0:17:48.280 --> 0:17:52.080 twenty five nanometers in diameter, which means you can line 0:17:52.160 --> 0:17:54.840 up four thousand of them across the width of a 0:17:54.920 --> 0:17:58.080 single human hair, and they're long too, so they stretch 0:17:58.200 --> 0:18:02.040 like tiny straws all through the interior of the neuron. 0:18:02.240 --> 0:18:06.240 Now what's amazing is these are constantly assembling and disassembling themselves, 0:18:06.280 --> 0:18:11.080 almost like living legos, and this adjusts the internal architecture 0:18:11.119 --> 0:18:15.200 of the cell in real time. So Stuart got interested 0:18:15.280 --> 0:18:18.640 in these microtubules and wondered if they were more than 0:18:18.840 --> 0:18:20.680 just railroad tracks. 0:18:20.720 --> 0:18:21.760 Back to Stuart Well. 0:18:21.680 --> 0:18:24.640 Micro teams are found in all cells, including neurons, which 0:18:24.680 --> 0:18:27.120 are full of them, and they are like the skeleton 0:18:27.800 --> 0:18:30.040 and the scaffolding on the cell, but they're also the 0:18:30.080 --> 0:18:33.280 nervous system of the cell. They organize things, and their 0:18:33.320 --> 0:18:36.080 structure I learned back then is a lattice kind of 0:18:36.119 --> 0:18:39.720 like a computer lattice, where you have individual units proteins 0:18:39.720 --> 0:18:43.440 called turbulence that I thought back then can be in 0:18:43.480 --> 0:18:47.880 two states, like flexing like a peanut open and closed, 0:18:48.080 --> 0:18:49.760 and that would be like a bit at one or zero. 0:18:49.960 --> 0:18:52.920 So Hammerff is looking carefully at these and he proposed 0:18:53.200 --> 0:18:57.239 that microtubules might be doing something beyond structural work, that 0:18:57.480 --> 0:19:01.240 instead of just looking at the microtubule as a roadway, 0:19:01.560 --> 0:19:05.159 you might think about the details of the microtubules and 0:19:05.320 --> 0:19:08.679 ask whether this could be a structure that was a 0:19:08.680 --> 0:19:11.800 lot more interesting than it first appeared. So he started 0:19:11.880 --> 0:19:15.560 modeling tubulens, the little bricks of microtubules, and came to 0:19:15.600 --> 0:19:18.480 the conclusion that you could store something like ten to 0:19:18.520 --> 0:19:23.440 the sixteenth bits of information in a single neuron using microtubules. 0:19:23.680 --> 0:19:25.880 And this was essentially the number that people were talking 0:19:25.960 --> 0:19:28.760 about for the storage capacity of the entire brain. 0:19:29.440 --> 0:19:31.520 Now, his colleagues were skeptical. They didn't want to hear it. 0:19:31.520 --> 0:19:32.359 Tell me to get lost. 0:19:32.920 --> 0:19:36.480 So except then one day, fateful day, this guy said 0:19:36.520 --> 0:19:39.040 to me, Okay, why is that asked? Let's say you're right, 0:19:39.080 --> 0:19:43.560 how would that explain consciousness? How would that explain love, feelings, pinkness, joy, 0:19:43.600 --> 0:19:47.200 blah blah blah. Essentially the hard problem five years before 0:19:47.320 --> 0:19:52.520 Dave announces. But you knew the problem, I said, WHOA, 0:19:52.600 --> 0:19:55.000 you're right, I have no idea. I was a reductionist nudgeon, 0:19:55.040 --> 0:19:56.920 and I was ashamed of myself. 0:19:56.960 --> 0:19:58.760 Actually, so we actually just want to say, I want 0:19:58.800 --> 0:20:00.879 to make sure everyone's following. So the hard problem of 0:20:00.920 --> 0:20:03.320 consciousness is you've got all this physical stuff happening in 0:20:03.320 --> 0:20:05.119 the brain, why does it feel like anything. 0:20:05.119 --> 0:20:07.560 Why do we have experience? That's the hard problem. 0:20:07.560 --> 0:20:10.320 Okay, Right, so you were looking at these microtubules which 0:20:10.320 --> 0:20:13.239 are made up of these tubulin peanut shaped proteins, and 0:20:13.280 --> 0:20:17.040 you're saying, hey, there's something really interesting here. But it 0:20:17.080 --> 0:20:18.560 didn't solve the hard problem. 0:20:18.960 --> 0:20:19.240 Right. 0:20:19.320 --> 0:20:23.159 So I was just saying, more computation, more information processing. 0:20:23.320 --> 0:20:25.840 So and the guy had a beautiful point, and I 0:20:25.880 --> 0:20:27.560 was kind of stunned. And he said, you should read 0:20:27.600 --> 0:20:30.320 this book by Roger Penrose called The Emperor's New Mind. 0:20:30.800 --> 0:20:32.600 I said, I've kind of heard of that guy. So 0:20:32.680 --> 0:20:34.439 I bought the book. I read it, and I was 0:20:34.560 --> 0:20:37.040 kind of blown away. I mean, it's an amazing book. 0:20:37.480 --> 0:20:40.840 The first half is about why consciousness is not a computation. 0:20:41.560 --> 0:20:44.640 He used something called Girdle's theorem from mathematics, which said 0:20:44.800 --> 0:20:47.920 a mathematical theorem cannot prove itself. You need somebody or 0:20:47.960 --> 0:20:50.960 something outside the system, like a mathematician, to say yeah, 0:20:51.000 --> 0:20:53.600 it's true or not. And he extrapolated and said it's 0:20:53.640 --> 0:20:56.119 like understanding, you know, to understand something, you need to 0:20:56.240 --> 0:20:59.760 be outside the system, very similar to John Searle's Chinese 0:20:59.840 --> 0:21:02.560 room argument. You know, the guy has the Chinese symbols. 0:21:02.560 --> 0:21:04.359 He looks them up and he translates, but he doesn't 0:21:04.400 --> 0:21:05.359 understand Chinese. 0:21:05.640 --> 0:21:08.720 So that's the sense just doing computer operations, right. 0:21:08.560 --> 0:21:11.800 And so that was the difference and Roger. So the 0:21:11.840 --> 0:21:14.360 second half of the book was Roger's solution, which had 0:21:14.359 --> 0:21:16.520 something to do with quantum physics and collapse of the 0:21:16.560 --> 0:21:19.520 wave function, the measurement problem in quantum Kinnis, which was 0:21:19.560 --> 0:21:22.800 a whole other mystery. But he said, the solution to 0:21:22.840 --> 0:21:25.639 that mystery is the same as is for consciousness. But 0:21:25.760 --> 0:21:29.159 Roger didn't have a biological structure that could be at 0:21:29.200 --> 0:21:31.040 the quantum level. And he said in the book, I 0:21:31.040 --> 0:21:33.399 don't know what it is. Maybe somebody does. So I 0:21:33.440 --> 0:21:35.880 read the book and I said, holy crap, he needs microtubules. 0:21:35.960 --> 0:21:37.280 I've been studying for twenty years. 0:21:37.359 --> 0:21:40.320 So Stuart wrote Roger a letter. 0:21:40.640 --> 0:21:45.120 But then Stuart Haerrov read my book and wrote back 0:21:45.119 --> 0:21:49.320 to me said, evidently you don't know about microtubules. He 0:21:49.400 --> 0:21:53.119 was absolutely right. If I'd known about microtubules, that's it. 0:21:53.200 --> 0:21:57.959 Here's a much better bet. For various reasons, they are 0:21:58.280 --> 0:22:01.919 probably because they're too See. It seemed to me that 0:22:02.000 --> 0:22:06.680 there is a much better chance you could isolate quantum effection. 0:22:06.800 --> 0:22:09.680 So they met up in England and Roger was very 0:22:09.720 --> 0:22:13.960 taken by the geometry of these microtubules. Tell us what 0:22:14.119 --> 0:22:15.840 is special about microtubules? 0:22:16.080 --> 0:22:20.160 Well, what's special about microtubules? There's several things which excited 0:22:20.200 --> 0:22:23.000 me about them. Some of them are sort of peripheral, 0:22:23.119 --> 0:22:28.080 but not so stupid. Maybe they are two to begin with, 0:22:29.000 --> 0:22:33.040 and that struck me as much better chance preserve coherence. 0:22:33.680 --> 0:22:35.119 You see, if you're going to have the collapse of 0:22:35.119 --> 0:22:37.080 the wave function, you've got to have a well defined 0:22:37.080 --> 0:22:41.160 wave function which isn't collapsed by the environment. You see, 0:22:41.200 --> 0:22:44.359 normally what happens is that the environment collapses that and 0:22:44.359 --> 0:22:46.960 that's no use to anybody this standard, As I say, 0:22:47.040 --> 0:22:52.120 Ladi von Neumann arguments, do you say that the collapse 0:22:52.160 --> 0:22:56.120 occurs because the environment gets involved? You have no control 0:22:56.160 --> 0:22:59.920 over the environment and so therefore it behaves randomly in someone. 0:23:00.480 --> 0:23:03.800 In other words, he's pointing out that the environment normally 0:23:03.840 --> 0:23:07.600 collapses the wave function very rapidly. But he appreciated the 0:23:07.640 --> 0:23:12.320 possibility that microtubules might serve as a wave guide, which 0:23:12.320 --> 0:23:15.679 means there's something about the particular structure of these long, 0:23:15.800 --> 0:23:20.000 thin straws that keeps the wave function uncollapsed for a 0:23:20.119 --> 0:23:21.399 longer time. A. 0:23:21.600 --> 0:23:28.760 Their tubes. B. They have a very symmetrical structure of 0:23:28.920 --> 0:23:34.320 the tubulence, and they combined together in this particular structure, 0:23:34.320 --> 0:23:39.720 which I found fascinating because it has, for example, symmetries 0:23:39.880 --> 0:23:43.640 in three different directions. One is along the axis, one 0:23:43.720 --> 0:23:46.320 is twisting one way, and the other is twisting the 0:23:46.359 --> 0:23:49.920 other way. So it just struck me what's funny about 0:23:49.920 --> 0:23:53.440 these microtubules. You have these microtubules which have one direction 0:23:54.400 --> 0:23:59.320 along the tube, and that seems mirror what you get 0:23:59.440 --> 0:24:03.720 in these tubes, that they become super conductive. So this 0:24:03.840 --> 0:24:09.639 suggested to me that maybe there is some quantum super 0:24:09.640 --> 0:24:13.600