1 00:00:01,280 --> 00:00:03,320 Speaker 1: Hey, it' Jorhan Daniel here, and we want to tell 2 00:00:03,360 --> 00:00:06,840 Speaker 1: you about our new book. It's called Frequently Asked Questions 3 00:00:06,960 --> 00:00:09,719 Speaker 1: about the Universe because you have questions about the universe, 4 00:00:09,760 --> 00:00:12,360 Speaker 1: and so we decided to write a book all about them. 5 00:00:12,440 --> 00:00:14,800 Speaker 1: We talk about your questions, we give some answers, we 6 00:00:14,880 --> 00:00:17,560 Speaker 1: make a bunch of silly jokes as usual, and we 7 00:00:17,600 --> 00:00:20,159 Speaker 1: tackle all kinds of questions, including what happens if I 8 00:00:20,200 --> 00:00:22,880 Speaker 1: fall into a black hole? Or is there another version 9 00:00:22,920 --> 00:00:25,480 Speaker 1: of you out there that's right? Like usual, we tackle 10 00:00:25,600 --> 00:00:29,960 Speaker 1: the deepest, darkest, biggest, craziest questions about this incredible cosmos. 11 00:00:29,960 --> 00:00:31,800 Speaker 1: If you want to support the podcast, please get the 12 00:00:31,800 --> 00:00:33,879 Speaker 1: book and get a copy not just for yourself, but 13 00:00:34,120 --> 00:00:39,320 Speaker 1: you know, for your nieces and nephews, cousins, friends, parents, dogs, hamsters, 14 00:00:39,400 --> 00:00:42,640 Speaker 1: and for the aliens. So get your copy of Frequently 15 00:00:42,720 --> 00:00:46,440 Speaker 1: Asked Questions about the Universe is available for pre order now, 16 00:00:46,560 --> 00:00:49,239 Speaker 1: coming out November two. You can find more details at 17 00:00:49,240 --> 00:00:53,160 Speaker 1: the book's website, Universe f a Q dot com. Thanks 18 00:00:53,159 --> 00:00:55,000 Speaker 1: for your support, and if you have a hamster that 19 00:00:55,040 --> 00:00:57,240 Speaker 1: can read, please let us know. We'd love to have 20 00:00:57,320 --> 00:01:10,320 Speaker 1: them on the podcast. We all know that quantum mechanics 21 00:01:10,560 --> 00:01:14,920 Speaker 1: can't be quite right. I'm not talking about the counter intuitive, 22 00:01:15,160 --> 00:01:18,440 Speaker 1: probabilistic aspects of it that it forced us to accept 23 00:01:18,520 --> 00:01:22,240 Speaker 1: that the world we live in is fundamentally weirder than 24 00:01:22,319 --> 00:01:27,080 Speaker 1: we have ever imagined. Probabilities and correlations and uncertainty is no. 25 00:01:27,480 --> 00:01:30,800 Speaker 1: Those bits are probably right, But there's a problem at 26 00:01:30,840 --> 00:01:34,720 Speaker 1: the heart of quantum mechanics, one that has baffled physicists 27 00:01:34,720 --> 00:01:38,320 Speaker 1: and philosophers for nearly a hundred years, and that may 28 00:01:38,360 --> 00:01:42,840 Speaker 1: take another hundred years to solve. But some recent ideas 29 00:01:43,120 --> 00:01:46,240 Speaker 1: maybe showing us a path forward, even if it's a 30 00:01:46,360 --> 00:02:05,000 Speaker 1: stranger path. Then we imagine, Hi, I'm Daniel. I'm a 31 00:02:05,000 --> 00:02:08,280 Speaker 1: particle physicist and a professor at u C Irvine, and 32 00:02:08,400 --> 00:02:13,560 Speaker 1: I'm still confused by quantum mechanics. Confused but not frustrated, 33 00:02:13,919 --> 00:02:17,200 Speaker 1: You might say, I'm deliciously confused. What could be more 34 00:02:17,240 --> 00:02:20,639 Speaker 1: delightful than grappling with the deep mysteries of the nature 35 00:02:20,680 --> 00:02:24,080 Speaker 1: of reality, seeing the truth written down in cold black 36 00:02:24,120 --> 00:02:27,440 Speaker 1: and white and mathematical equations, and struggling to gain an 37 00:02:27,440 --> 00:02:32,520 Speaker 1: intuition to incorporate those alien concepts into our human brains. 38 00:02:32,600 --> 00:02:36,720 Speaker 1: After all, that is the deepest goal of physics, and 39 00:02:36,760 --> 00:02:39,960 Speaker 1: that's the goal of our podcast. Daniel and Jorgey explain 40 00:02:40,040 --> 00:02:42,960 Speaker 1: the university production of My Heart Radio, in which we 41 00:02:43,040 --> 00:02:46,760 Speaker 1: tackled the biggest and hardest and nastiest and funnest of 42 00:02:46,880 --> 00:02:50,600 Speaker 1: questions of the universe, the ones that make your brains twist, 43 00:02:50,639 --> 00:02:53,080 Speaker 1: the ones that slip away from you just as you 44 00:02:53,160 --> 00:02:55,440 Speaker 1: thought you had figured them out, the ones that might 45 00:02:55,480 --> 00:03:00,240 Speaker 1: elude humanity for centuries or forever. We don't show away 46 00:03:00,280 --> 00:03:02,800 Speaker 1: from any questions on the podcast, but we seek to 47 00:03:02,840 --> 00:03:06,880 Speaker 1: approach them and explain our knowledge and our ignorance to you. 48 00:03:07,200 --> 00:03:09,440 Speaker 1: My friend and co host Jorge is on a break, 49 00:03:09,440 --> 00:03:12,040 Speaker 1: but I have a special treat for you. We are 50 00:03:12,200 --> 00:03:14,480 Speaker 1: very lucky to have as a guest one of my 51 00:03:14,639 --> 00:03:18,600 Speaker 1: favorite physicists, one of my favorite writers, and one of 52 00:03:18,639 --> 00:03:23,120 Speaker 1: my favorite writers about physics, truly a poet of science communication. 53 00:03:23,200 --> 00:03:26,680 Speaker 1: Today we'll be talking to Carlo Rovelli about some of 54 00:03:26,720 --> 00:03:29,919 Speaker 1: the problems at the heart of quantum mechanics and explaining 55 00:03:30,000 --> 00:03:35,600 Speaker 1: a lesser known but absolutely fascinating alternative version of quantum mechanics. 56 00:03:35,640 --> 00:03:38,240 Speaker 1: So today on the podcast, we'll be answering the question 57 00:03:43,240 --> 00:03:47,840 Speaker 1: what is relational quantum mechanics? So it's my great pleasure 58 00:03:47,840 --> 00:03:51,080 Speaker 1: today to introduce Professor Carlo Rovelli. He's a professor of 59 00:03:51,080 --> 00:03:53,440 Speaker 1: physics in Marseille, and he cut his teeth and made 60 00:03:53,440 --> 00:03:56,720 Speaker 1: his name for himself developing theories of quantum gravity, mostly 61 00:03:56,800 --> 00:03:59,840 Speaker 1: loop quantum gravity. If I understand correctly, he also became 62 00:03:59,880 --> 00:04:02,000 Speaker 1: a household name. Is the author of the book Seven 63 00:04:02,040 --> 00:04:04,440 Speaker 1: Brief Lessons on Physics, which sold more than a million 64 00:04:04,480 --> 00:04:07,920 Speaker 1: copies and was translated into forty one languages. I've read 65 00:04:07,920 --> 00:04:10,680 Speaker 1: it and enjoyed it immensely and heartily recommended to you. Today, 66 00:04:10,680 --> 00:04:12,600 Speaker 1: Professor Rivelli is here to talk to us about his 67 00:04:12,640 --> 00:04:16,240 Speaker 1: new book, Hell Go Land and a fascinating alternative take 68 00:04:16,400 --> 00:04:19,920 Speaker 1: on the measurement problem in quantum mechanics. Professor Velli, welcome 69 00:04:19,960 --> 00:04:22,200 Speaker 1: to the podcast, and thank you for joining us. Thank 70 00:04:22,240 --> 00:04:24,440 Speaker 1: you question that it's a pleasure in the honor of 71 00:04:24,480 --> 00:04:28,240 Speaker 1: being here, wonderful. Well. I always love talking about quantum 72 00:04:28,240 --> 00:04:31,080 Speaker 1: mechanics and puzzling over it with other people. I feel 73 00:04:31,120 --> 00:04:33,440 Speaker 1: like every time I talk about quantum mechanics with somebody else, 74 00:04:33,720 --> 00:04:36,240 Speaker 1: I think of a new question I've never thought of before, 75 00:04:36,680 --> 00:04:38,760 Speaker 1: or a new angle on it, or a new mystery 76 00:04:38,800 --> 00:04:41,320 Speaker 1: frankly like a new corner of my mind that I 77 00:04:41,360 --> 00:04:44,040 Speaker 1: haven't ever really examined, and I get confused, and so 78 00:04:44,080 --> 00:04:46,120 Speaker 1: it's always fun to figure things outside of on the fly. 79 00:04:46,520 --> 00:04:48,719 Speaker 1: So today we wanted to talk about your new book 80 00:04:48,880 --> 00:04:51,640 Speaker 1: and Hell Go Land, And the book essentially lays out 81 00:04:51,720 --> 00:04:56,240 Speaker 1: for lay audience this idea of relational quantum mechanics, sort 82 00:04:56,279 --> 00:04:59,040 Speaker 1: of a new interpretation on quantum mechanics. And the first 83 00:04:59,080 --> 00:05:01,719 Speaker 1: question for you I have is if you could describe 84 00:05:01,720 --> 00:05:06,040 Speaker 1: for us what is the problem that relational quantum mechanics solves, Like, 85 00:05:06,160 --> 00:05:09,920 Speaker 1: why do we need another quantum mechanics interpretation? What is it? 86 00:05:09,960 --> 00:05:12,880 Speaker 1: At the heart of relational quantum mechanics is trying to 87 00:05:12,960 --> 00:05:16,479 Speaker 1: do One of the difficulties the problem of quantum mechanics 88 00:05:16,720 --> 00:05:21,080 Speaker 1: is to say exactly what the problem is. So quass mechanics, 89 00:05:21,080 --> 00:05:24,960 Speaker 1: on the one hand, it's extraordinary successful, is used in 90 00:05:25,440 --> 00:05:28,400 Speaker 1: a lot of our technology, is used a lot of 91 00:05:28,440 --> 00:05:31,719 Speaker 1: our understanding of the world world. We explain with quantum 92 00:05:31,720 --> 00:05:37,800 Speaker 1: mechanics the basics of chemistry, basic apastrophysics, all sorts of stuff, 93 00:05:37,839 --> 00:05:40,440 Speaker 1: and it works. It works fantastically. On the other hand, 94 00:05:40,680 --> 00:05:45,200 Speaker 1: there is a persisting, mysterious aspect about this theory. It's 95 00:05:45,200 --> 00:05:47,799 Speaker 1: a theory that it's a it's sort of formulity differently 96 00:05:48,080 --> 00:05:53,720 Speaker 1: than previous basic physical theories. This difference puzzles everybody, and 97 00:05:54,120 --> 00:05:57,600 Speaker 1: this is where the problems can in because the scientists 98 00:05:57,680 --> 00:06:01,479 Speaker 1: disagree about how to think abou quantum mechanics. If you 99 00:06:01,640 --> 00:06:03,839 Speaker 1: if you want to, if you go to a physicist 100 00:06:03,920 --> 00:06:07,760 Speaker 1: conference and you want to really start a furious discussion, 101 00:06:08,279 --> 00:06:11,120 Speaker 1: just like drop the question at the banquets, say oh, 102 00:06:11,160 --> 00:06:14,120 Speaker 1: by the way, what do you think going to mechanics, 103 00:06:14,200 --> 00:06:16,960 Speaker 1: And ten minutes later everyone's screaming against everybody. But is 104 00:06:17,000 --> 00:06:20,320 Speaker 1: this a conference of philosophers or physicists in your mind? No, 105 00:06:20,440 --> 00:06:23,520 Speaker 1: No physicist physicist physicism, including the one to say there's 106 00:06:23,560 --> 00:06:25,640 Speaker 1: no problem at all, what are you talking about? And 107 00:06:25,680 --> 00:06:29,240 Speaker 1: that they say, of course there's a problem. You know, 108 00:06:29,320 --> 00:06:31,039 Speaker 1: where is the problem? I mean, how how can we 109 00:06:31,120 --> 00:06:35,119 Speaker 1: characterize the problem? Well? Sort of all physical theories from 110 00:06:35,560 --> 00:06:38,560 Speaker 1: saying Newton or maybe even before from the card or 111 00:06:38,560 --> 00:06:42,479 Speaker 1: even from Aristotle all the way to Maxwell and Twinstein, 112 00:06:43,520 --> 00:06:48,680 Speaker 1: special activity, general activity, electro dynamics. The theories describes the 113 00:06:48,839 --> 00:06:52,280 Speaker 1: systems and just the sens the system with some variables. 114 00:06:52,560 --> 00:06:55,200 Speaker 1: I don't know a pendulum. It's a physical object and 115 00:06:55,279 --> 00:06:58,360 Speaker 1: the variable is the angle with the vertical and tell 116 00:06:58,400 --> 00:07:03,600 Speaker 1: you how this variable ease and evolves. Given something that 117 00:07:03,640 --> 00:07:05,520 Speaker 1: you know at the beginning and you know where it is, 118 00:07:05,600 --> 00:07:07,320 Speaker 1: you know the velocity, and then you have you have 119 00:07:07,360 --> 00:07:10,200 Speaker 1: any questions that tell you how the variable changes continuously 120 00:07:10,200 --> 00:07:13,680 Speaker 1: in time. So of course this allows assume ex predictions 121 00:07:13,680 --> 00:07:17,000 Speaker 1: because we can measure the position. The velocity doesn't close 122 00:07:17,000 --> 00:07:20,960 Speaker 1: our eyes with two seconds, open again and the new position. 123 00:07:21,000 --> 00:07:24,480 Speaker 1: New velocity can be predicted by the theory because they 124 00:07:24,560 --> 00:07:27,400 Speaker 1: tell us exactly how it moves in time. So that's 125 00:07:27,440 --> 00:07:31,400 Speaker 1: how Newton physics works, or Maxwell theory works of ice. 126 00:07:31,440 --> 00:07:34,200 Speaker 1: Since theory works well probamical, it does not work this way. 127 00:07:34,440 --> 00:07:37,640 Speaker 1: That's the point. It works in a completely different manner. 128 00:07:38,560 --> 00:07:41,840 Speaker 1: It does not tell us what happens at the pendulum 129 00:07:42,160 --> 00:07:47,880 Speaker 1: while he's moving. It only tells us the prediction without 130 00:07:47,880 --> 00:07:50,920 Speaker 1: saying what is in between. And if you try to reconstruct, 131 00:07:50,960 --> 00:07:53,960 Speaker 1: what is this in between? So the data that you 132 00:07:54,040 --> 00:07:57,600 Speaker 1: know and the prediction that you make, all devils go loose, 133 00:07:58,040 --> 00:08:02,280 Speaker 1: namely every stray. Things happen, and people disagree about what 134 00:08:02,400 --> 00:08:05,560 Speaker 1: happened in between in between, you mean that moment when 135 00:08:05,600 --> 00:08:07,600 Speaker 1: you close your eyes and you're trying to use physics 136 00:08:07,640 --> 00:08:11,720 Speaker 1: to predict the future exactly. So typically think about quantum 137 00:08:11,720 --> 00:08:13,680 Speaker 1: mechanics in this way. I mean, you make a measurement, 138 00:08:13,800 --> 00:08:17,760 Speaker 1: that's the language which is used. They'll certainly makes a measurement, 139 00:08:18,000 --> 00:08:20,160 Speaker 1: and you make a prediction of what's going to happen 140 00:08:20,520 --> 00:08:24,840 Speaker 1: at the next measurement sometime later, and the prediction is binger. 141 00:08:25,120 --> 00:08:28,160 Speaker 1: It works. I mean, it tell us exactly what we see, 142 00:08:28,280 --> 00:08:31,680 Speaker 1: but if you ask what happened in between, it's confusing. 143 00:08:31,680 --> 00:08:34,680 Speaker 1: And the reason it's confusing one way of presenting it, 144 00:08:34,840 --> 00:08:37,040 Speaker 1: one of the many ways of presenting it is the following. 145 00:08:37,480 --> 00:08:40,000 Speaker 1: If you have a particle, an electron, or a little 146 00:08:40,040 --> 00:08:42,840 Speaker 1: mole for that, or an atom remocal, and you throw 147 00:08:42,920 --> 00:08:45,840 Speaker 1: it in some way, then going to mechanics tell you 148 00:08:45,960 --> 00:08:48,600 Speaker 1: where it's going to be, or at least probility distribution 149 00:08:48,600 --> 00:08:50,360 Speaker 1: of what's going to be. Because the prediction about the 150 00:08:50,360 --> 00:08:53,400 Speaker 1: mechanics and probabilistics are not not exactly that's one of 151 00:08:53,400 --> 00:08:55,920 Speaker 1: the corrector is still going to mechanics, but it's telling 152 00:08:55,960 --> 00:08:58,360 Speaker 1: me the sort of probility going to be here that 153 00:08:58,360 --> 00:09:00,280 Speaker 1: you're probably going to be here, to be going to 154 00:09:00,360 --> 00:09:04,679 Speaker 1: be here. Then in between, what happens to the mathematics 155 00:09:04,840 --> 00:09:09,040 Speaker 1: is the particle opens up in a wave. It's it's everywhere, 156 00:09:09,520 --> 00:09:13,120 Speaker 1: and with this way you compute the different probabilities, so 157 00:09:13,640 --> 00:09:17,640 Speaker 1: the particles at the same time many positions in the mathematics. 158 00:09:18,080 --> 00:09:21,199 Speaker 1: So some people say, okay, so the particle isn't many, 159 00:09:21,320 --> 00:09:23,840 Speaker 1: it's a wave, it's all over. But then when you 160 00:09:23,880 --> 00:09:25,840 Speaker 1: look at the particle is not a way. It's in 161 00:09:25,880 --> 00:09:28,680 Speaker 1: a single position. So other people say, no, come on, 162 00:09:28,880 --> 00:09:30,880 Speaker 1: I mean, we look at the particle is always a particle. 163 00:09:30,920 --> 00:09:33,000 Speaker 1: When we look where it is, it is always in 164 00:09:33,120 --> 00:09:37,040 Speaker 1: one point. But when you compute how it goes from 165 00:09:37,040 --> 00:09:40,240 Speaker 1: from here to here, it's not in one point. And 166 00:09:40,280 --> 00:09:43,000 Speaker 1: if you assume that it is in one point, you're 167 00:09:43,080 --> 00:09:45,560 Speaker 1: led to make some kind of mistakes and things like that. 168 00:09:45,840 --> 00:09:49,760 Speaker 1: So it's capable of making predictions, concrete predictions, or be 169 00:09:49,800 --> 00:09:52,680 Speaker 1: can compared to measurements. But to make those predictions you 170 00:09:52,720 --> 00:09:56,600 Speaker 1: need this intermediate step, which seems sort of nonsensical and 171 00:09:56,920 --> 00:09:59,040 Speaker 1: conflicts with our sense of like what is real in 172 00:09:59,080 --> 00:10:02,840 Speaker 1: the universe around exactly. So, but the real problem, it's 173 00:10:03,679 --> 00:10:06,000 Speaker 1: the thing people are debating with is what does it 174 00:10:06,040 --> 00:10:11,079 Speaker 1: mean that the theory describe what we measure. That's why 175 00:10:11,120 --> 00:10:14,000 Speaker 1: it's called the measurement problem. In a sense, it's like 176 00:10:14,120 --> 00:10:18,640 Speaker 1: when we measure something special happened, But we are not special, right, 177 00:10:18,720 --> 00:10:21,200 Speaker 1: We are just you know, piece of the universe like 178 00:10:21,240 --> 00:10:25,040 Speaker 1: any others. So the standard formulation of quantum mechanics, the 179 00:10:25,080 --> 00:10:28,920 Speaker 1: one reading textbooks, it's only in terms of the observer 180 00:10:29,120 --> 00:10:31,320 Speaker 1: and the measurement, which is fine as long as you 181 00:10:31,360 --> 00:10:34,640 Speaker 1: don't ask, what about the physics of the observer? What 182 00:10:34,720 --> 00:10:39,199 Speaker 1: about the observer itself isn't to observe itself a quantum system, 183 00:10:39,400 --> 00:10:42,000 Speaker 1: so it should be described the quantum mechanics as well, 184 00:10:42,280 --> 00:10:44,160 Speaker 1: so it should also open up on it like a wave. 185 00:10:44,920 --> 00:10:47,959 Speaker 1: But that's it, and that's where people start disagree. And 186 00:10:48,360 --> 00:10:51,200 Speaker 1: some physicists thinkly, yes, we do. We do our waves 187 00:10:51,679 --> 00:10:55,320 Speaker 1: the multiple copies of Daniel and me and Carolo and 188 00:10:55,440 --> 00:10:58,520 Speaker 1: some versions of us, some some some answers are given, 189 00:10:58,520 --> 00:11:01,280 Speaker 1: is some other versions of different. It is given because 190 00:11:01,320 --> 00:11:05,640 Speaker 1: we're a wave of different configurations of ourselves. Other people think, no, 191 00:11:05,760 --> 00:11:07,880 Speaker 1: come on, that's not a good way of thinking about reality. 192 00:11:07,960 --> 00:11:12,120 Speaker 1: And that's where the the disagreement start. So the disagreement 193 00:11:12,600 --> 00:11:15,400 Speaker 1: is realized in the number of so called interpretations of 194 00:11:15,440 --> 00:11:18,680 Speaker 1: quanto methadnics ways to make sense about this funny story 195 00:11:18,720 --> 00:11:22,120 Speaker 1: about the observer and the measurement and on the market 196 00:11:22,240 --> 00:11:26,079 Speaker 1: that there are many but maybe three or four or 197 00:11:26,120 --> 00:11:29,480 Speaker 1: four or five which are dominant, and many variants of 198 00:11:29,559 --> 00:11:32,040 Speaker 1: these which is pretty different from one another, and give 199 00:11:32,080 --> 00:11:34,959 Speaker 1: a profoundly different picture of reality. And that's the beauty 200 00:11:34,960 --> 00:11:37,559 Speaker 1: of the story. It's not just a technical thing about 201 00:11:37,640 --> 00:11:39,320 Speaker 1: using the theory. In fact, it's not the technical thing 202 00:11:39,360 --> 00:11:41,880 Speaker 1: about using Everybody agrees on using the theory, but everybody 203 00:11:41,920 --> 00:11:45,439 Speaker 1: disagrees on if you want on what happens between the measurements, 204 00:11:45,480 --> 00:11:47,280 Speaker 1: that's what way you're putting it. So I think it's 205 00:11:47,280 --> 00:11:50,679 Speaker 1: really fascinating that it's so important to us to understand 206 00:11:51,080 --> 00:11:55,040 Speaker 1: what happens when we're not looking. Right. Clearly, physics takes 207 00:11:55,080 --> 00:11:57,440 Speaker 1: it very important to predict what happens when we look, 208 00:11:57,520 --> 00:11:59,800 Speaker 1: because it's very practical. We need to know how trans 209 00:12:00,000 --> 00:12:02,959 Speaker 1: star's working, whether our airplanes will fly. But when we're 210 00:12:02,960 --> 00:12:04,960 Speaker 1: not making measurements, where we're not looking, when we're not 211 00:12:05,000 --> 00:12:08,040 Speaker 1: watching the universe, we still want to know what is real, 212 00:12:08,120 --> 00:12:09,760 Speaker 1: what is going on? We want to have like a 213 00:12:09,800 --> 00:12:13,199 Speaker 1: model in our minds of how the universe works. Are 214 00:12:13,240 --> 00:12:15,439 Speaker 1: we still doing physics in that case there's that philosophy 215 00:12:15,520 --> 00:12:17,559 Speaker 1: or do you think they're you know, forever intertwined. I 216 00:12:17,600 --> 00:12:20,480 Speaker 1: think they're forever intertwined, and I think they should be 217 00:12:20,520 --> 00:12:24,719 Speaker 1: forever intertwined, because it's precisely by asking those kinds of 218 00:12:24,800 --> 00:12:31,920 Speaker 1: questions that in the past physics has made the big jumps. Um, 219 00:12:32,040 --> 00:12:34,480 Speaker 1: let me make an example of maybe two. What example 220 00:12:34,600 --> 00:12:38,440 Speaker 1: is is the Earth the center of the universe. This 221 00:12:38,600 --> 00:12:41,959 Speaker 1: was a huge debate at the time of between Copernicus 222 00:12:42,040 --> 00:12:45,360 Speaker 1: and Newton. It's it's it's a center of debate, and 223 00:12:46,040 --> 00:12:48,600 Speaker 1: nobody could say that this was not a scientific debate, 224 00:12:48,880 --> 00:12:52,560 Speaker 1: because that's the debate that started that allowed Newton to 225 00:12:52,559 --> 00:12:56,439 Speaker 1: do new to mechanics and allowed Galileo to understand the 226 00:12:56,480 --> 00:13:00,720 Speaker 1: Gali little relativity, and this debate on on which Kepler BILLT. 227 00:13:00,840 --> 00:13:05,240 Speaker 1: Kepler was a strenuous defender of the idea that there 228 00:13:05,400 --> 00:13:07,320 Speaker 1: is not the center the universe. The universe is not 229 00:13:07,400 --> 00:13:09,679 Speaker 1: the center. Going around the said, but if you think 230 00:13:09,720 --> 00:13:12,840 Speaker 1: for a moment, is this Earth as the central universe? 231 00:13:13,200 --> 00:13:16,840 Speaker 1: A scientific question in the sense of something we can 232 00:13:16,880 --> 00:13:20,320 Speaker 1: test them, of course not. There's no way of testing. 233 00:13:20,360 --> 00:13:23,920 Speaker 1: There's no there's no operational meaning, there's no measurement that 234 00:13:23,920 --> 00:13:27,480 Speaker 1: I can make that can distinguish if there Earth is 235 00:13:27,520 --> 00:13:30,000 Speaker 1: the central universe. So it is not because you know, 236 00:13:30,040 --> 00:13:32,440 Speaker 1: I mean it can stay somewhere and see moving. But 237 00:13:32,559 --> 00:13:34,560 Speaker 1: what does it mean if I am moving, I see 238 00:13:34,600 --> 00:13:38,360 Speaker 1: I I see the center moving. So it's really a 239 00:13:38,559 --> 00:13:43,920 Speaker 1: non empirical question. And yet it's a profound way scientific question. 240 00:13:44,400 --> 00:13:48,320 Speaker 1: Why because it gives a different way depending if you 241 00:13:48,360 --> 00:13:50,880 Speaker 1: answer one way or the other. If you start by 242 00:13:50,920 --> 00:13:53,319 Speaker 1: thinking there Earth is the center, everything goes around that all. 243 00:13:53,360 --> 00:13:55,200 Speaker 1: If you start by allowing there is to be one 244 00:13:55,280 --> 00:13:57,280 Speaker 1: of the things moves, so you go to a completely 245 00:13:57,320 --> 00:14:02,120 Speaker 1: different way for conceptualizing reality, and one which worked very well. 246 00:14:02,600 --> 00:14:04,520 Speaker 1: The other was bad. It was not the good one. 247 00:14:04,720 --> 00:14:07,920 Speaker 1: So I think this is one of the aspect of 248 00:14:07,960 --> 00:14:11,560 Speaker 1: science which I think is often misunderstood. They would say, 249 00:14:11,760 --> 00:14:15,080 Speaker 1: sciences is not just about you know, close your eye, 250 00:14:15,160 --> 00:14:18,520 Speaker 1: make make a model, make mathematics, make a measurement, make 251 00:14:18,559 --> 00:14:22,560 Speaker 1: a prediction, and that's it. Science is about understanding reality, 252 00:14:22,600 --> 00:14:27,200 Speaker 1: meaning building up a conceptual structure, the way you're thinking reality, 253 00:14:27,600 --> 00:14:30,760 Speaker 1: how to put things in cases. One way of putting 254 00:14:30,760 --> 00:14:32,840 Speaker 1: things in cases is in one case there's the Earth 255 00:14:33,640 --> 00:14:36,840 Speaker 1: and in the other the celestial bodies, the sound, the wound, 256 00:14:37,160 --> 00:14:40,120 Speaker 1: the planets, the stars, and then you throw that away. 257 00:14:40,280 --> 00:14:42,920 Speaker 1: That's that's that. That's not the right characterizasue. The right 258 00:14:42,920 --> 00:14:46,040 Speaker 1: way is there are stars, the planets, and then there 259 00:14:46,040 --> 00:14:49,800 Speaker 1: are satellites. Do something different and that's works really different, 260 00:14:50,040 --> 00:14:53,200 Speaker 1: and boom, we understand the universe better. So I think 261 00:14:53,280 --> 00:14:58,400 Speaker 1: there are questions which are not directly empirical but are scientific, 262 00:14:58,400 --> 00:15:01,280 Speaker 1: and I think the interpetitional quantum mechanics turn out something 263 00:15:01,360 --> 00:15:04,200 Speaker 1: like that, Namely, one way you're thinking about the story 264 00:15:04,280 --> 00:15:07,560 Speaker 1: will turn out to be useful on the long run. 265 00:15:20,320 --> 00:15:23,680 Speaker 1: So then let's dig into the details of the different interpretations, 266 00:15:24,000 --> 00:15:26,320 Speaker 1: just to recap for our listeners, what exactly is the 267 00:15:26,320 --> 00:15:28,200 Speaker 1: problem that we're trying to solve here. The way I 268 00:15:28,240 --> 00:15:30,920 Speaker 1: think about it sometimes is that we have these particles, 269 00:15:30,920 --> 00:15:33,720 Speaker 1: and our mathematical model of them is that they are probabilistic. 270 00:15:33,800 --> 00:15:35,800 Speaker 1: They can have the probability to be doing one thing 271 00:15:35,960 --> 00:15:38,120 Speaker 1: or another thing. But of course that's not what we 272 00:15:38,160 --> 00:15:40,680 Speaker 1: measure when we measure something, it does either one thing 273 00:15:41,120 --> 00:15:43,160 Speaker 1: or the other. And the question is, how do you 274 00:15:43,200 --> 00:15:46,760 Speaker 1: go from being probabilistic to being sort of classical. And 275 00:15:46,840 --> 00:15:49,680 Speaker 1: you know, it seems arbitrary to say I'm making a 276 00:15:49,720 --> 00:15:52,400 Speaker 1: measurement now or I'm not making a measurement, And you 277 00:15:52,400 --> 00:15:55,400 Speaker 1: can ask questions like, well, when it interacts with other particles, 278 00:15:55,440 --> 00:15:58,080 Speaker 1: why isn't that a measurement? Or if I'm making a 279 00:15:58,120 --> 00:16:00,480 Speaker 1: measurement and I'm using a stick, and you know the 280 00:16:00,520 --> 00:16:03,440 Speaker 1: tip of that stick is made of quantum mechanical particles, 281 00:16:03,440 --> 00:16:05,520 Speaker 1: So why doesn't it just interact with my stick the 282 00:16:05,520 --> 00:16:08,240 Speaker 1: way it interacts with other quantum mechanical particles and maintain 283 00:16:08,320 --> 00:16:11,000 Speaker 1: it's probabilistic nature. And you know, people think about like 284 00:16:11,320 --> 00:16:13,880 Speaker 1: do you have to have a conscious observer involved? But 285 00:16:13,920 --> 00:16:15,880 Speaker 1: there's all sorts of fun things that you can dig 286 00:16:15,920 --> 00:16:18,560 Speaker 1: into there. And had a fun conversation with the author 287 00:16:18,600 --> 00:16:21,160 Speaker 1: of What is Real, which people can also dig into 288 00:16:21,280 --> 00:16:23,320 Speaker 1: if they're interested in more details on what the measurement 289 00:16:23,320 --> 00:16:26,520 Speaker 1: problem is. And the classical approach to people take this 290 00:16:26,600 --> 00:16:30,680 Speaker 1: Copenhagen interpretation seems sort of arbitrary. It says that you know, 291 00:16:30,760 --> 00:16:33,320 Speaker 1: the wave function moves by the shorting air equation, and 292 00:16:33,320 --> 00:16:36,120 Speaker 1: it's smooth and continuous, and then boom, all of a sudden, 293 00:16:36,240 --> 00:16:38,920 Speaker 1: when there's a measurement, everything collapses. But it doesn't tell 294 00:16:38,960 --> 00:16:41,640 Speaker 1: you what a measurement is, right, And so there's this 295 00:16:41,760 --> 00:16:45,040 Speaker 1: deep question still the heart of the most common interpretation. 296 00:16:45,200 --> 00:16:47,480 Speaker 1: And let's listener as the podcast can also check out 297 00:16:47,480 --> 00:16:50,080 Speaker 1: our episodes on the Many World's interpretation. But today I 298 00:16:50,160 --> 00:16:52,800 Speaker 1: want to talk about your idea or this concept of 299 00:16:52,840 --> 00:16:56,400 Speaker 1: relational quantum mechanics. So how does relational quantum mechanics deal 300 00:16:56,480 --> 00:16:59,080 Speaker 1: with the measurement problem in a way that's different from 301 00:16:59,080 --> 00:17:03,600 Speaker 1: this our try obviously unworkable approach of the Copenhagen interpretation. 302 00:17:03,760 --> 00:17:06,400 Speaker 1: Yea very good and I think this is a nice 303 00:17:06,440 --> 00:17:10,120 Speaker 1: way of putting the question. Let's take a let's take 304 00:17:10,119 --> 00:17:13,960 Speaker 1: a concrete case. Was simplest the quantum mechanical experiment and 305 00:17:14,000 --> 00:17:16,159 Speaker 1: measurement that we can make. We can take an atom, 306 00:17:16,440 --> 00:17:19,879 Speaker 1: radioactive atom, right, just a piece of a block of 307 00:17:21,160 --> 00:17:25,479 Speaker 1: radius radius uranium. They waited there and you put around 308 00:17:25,520 --> 00:17:29,679 Speaker 1: it some detectors of radiation, you know, the guide detector, 309 00:17:29,680 --> 00:17:32,840 Speaker 1: the click when when a radiation arrives to wait for 310 00:17:32,880 --> 00:17:35,159 Speaker 1: a while and after a while, one of these clicks 311 00:17:35,280 --> 00:17:38,399 Speaker 1: flink okay, and then you say, okay, the atom has 312 00:17:38,400 --> 00:17:42,240 Speaker 1: emitted a radiation and it has been detected by these detectives. 313 00:17:42,280 --> 00:17:44,920 Speaker 1: This is the fact. Now, how do we describe this 314 00:17:45,600 --> 00:17:48,920 Speaker 1: in the equations? What we do when we do want 315 00:17:48,960 --> 00:17:52,400 Speaker 1: to mechanics, we pretend that this radiation is some particles 316 00:17:52,480 --> 00:17:56,080 Speaker 1: that are inside trapped inside the atoms, and they have 317 00:17:56,080 --> 00:17:58,800 Speaker 1: a wave that describe them is a wave the way 318 00:17:58,800 --> 00:18:02,359 Speaker 1: functions describes them and never automatics. These waves leaks out 319 00:18:03,400 --> 00:18:07,480 Speaker 1: from the atom or from the nucleus of the atom 320 00:18:07,640 --> 00:18:11,520 Speaker 1: slowly and continuously, and it's all over so and slowly. 321 00:18:11,720 --> 00:18:15,600 Speaker 1: The imagine that this this wave continuously leaking out. So 322 00:18:15,640 --> 00:18:19,840 Speaker 1: there's this continuously wave that around spherical and go out. 323 00:18:20,080 --> 00:18:23,440 Speaker 1: So each one of the detectors is touched by these waves. 324 00:18:23,480 --> 00:18:27,160 Speaker 1: Goes on. Then at some point the measurement happened. As 325 00:18:27,200 --> 00:18:32,119 Speaker 1: you say, something happens. We go from this quantum wave 326 00:18:32,320 --> 00:18:35,600 Speaker 1: to a classical factor, which is one single detector that happened, 327 00:18:36,240 --> 00:18:40,040 Speaker 1: and this is a measurement. Now, different interpretation try to 328 00:18:40,080 --> 00:18:42,320 Speaker 1: fill up the story in different way. Let me just 329 00:18:42,600 --> 00:18:46,960 Speaker 1: compare to one or two interpretation. What is the many 330 00:18:47,000 --> 00:18:49,040 Speaker 1: world interpretation that you mentioned, and the other is the 331 00:18:49,080 --> 00:18:52,880 Speaker 1: Copenagen interpretation that dimension the many world, in a sense 332 00:18:52,960 --> 00:18:55,840 Speaker 1: is the most radical idea of taking away very seriously, 333 00:18:56,000 --> 00:18:58,479 Speaker 1: the Copenaga interpetition is the one we study at school, 334 00:18:58,680 --> 00:19:00,800 Speaker 1: the one the teacher tell you tell you how to use. 335 00:19:01,000 --> 00:19:04,359 Speaker 1: So the many one interpretation says that there's this wave 336 00:19:04,400 --> 00:19:08,640 Speaker 1: that come out and you see only one detector clicking. 337 00:19:08,800 --> 00:19:11,080 Speaker 1: But why do you see one the technical clicking, Because 338 00:19:11,080 --> 00:19:16,080 Speaker 1: in reality, you yourself are a wave. Okay, So you, 339 00:19:16,080 --> 00:19:20,400 Speaker 1: yourself are a superposition of different you like the particle 340 00:19:20,440 --> 00:19:23,640 Speaker 1: and different positions in a superposition different positions. So it's 341 00:19:23,680 --> 00:19:26,000 Speaker 1: not true that there is one detector that clicks. All 342 00:19:26,000 --> 00:19:30,200 Speaker 1: the detectors clicks, but you yourself interacting with these detectors 343 00:19:30,320 --> 00:19:35,160 Speaker 1: split up in one you that sees this the technical clicking. 344 00:19:35,240 --> 00:19:38,119 Speaker 1: One UITs is that the tector clicking. One U that 345 00:19:38,440 --> 00:19:41,199 Speaker 1: is that the technical clipping, and so on. Okay, So 346 00:19:41,280 --> 00:19:45,960 Speaker 1: now you would imagine that the wave contains copies of you, 347 00:19:46,960 --> 00:19:48,800 Speaker 1: and the reason you've seen one and not the others 348 00:19:48,920 --> 00:19:51,639 Speaker 1: is only because you happen to be one copy of 349 00:19:51,640 --> 00:19:53,439 Speaker 1: you and not the other copies of the other. Now 350 00:19:53,480 --> 00:19:56,639 Speaker 1: does this work. Yes, it works. Is it plausible, Well, 351 00:19:57,160 --> 00:20:01,320 Speaker 1: it sounds very implausible, extremely implosed. Well, the problem is 352 00:20:01,359 --> 00:20:03,720 Speaker 1: everything you do with pant the mechanics sounds implausible. So 353 00:20:03,760 --> 00:20:06,199 Speaker 1: many people say, Okay, we have to accept this, that 354 00:20:06,600 --> 00:20:09,199 Speaker 1: in reality we live in immense waves, that the copies 355 00:20:09,240 --> 00:20:12,600 Speaker 1: and copies of ourselves, and that's the many world interpetation. 356 00:20:12,720 --> 00:20:14,640 Speaker 1: Can I ask you a question actually about that many 357 00:20:14,640 --> 00:20:17,000 Speaker 1: world interpretation? There is something about that that's never set 358 00:20:17,080 --> 00:20:19,679 Speaker 1: right with me. But maybe it's very naive and and 359 00:20:19,760 --> 00:20:21,920 Speaker 1: that's this you say that there are many, many copies 360 00:20:22,040 --> 00:20:25,120 Speaker 1: of me, And so it breaks the problem of why 361 00:20:25,200 --> 00:20:27,760 Speaker 1: is this one detector clicked by saying it's not just 362 00:20:27,840 --> 00:20:29,800 Speaker 1: that one detector clicked, all of them have clicked, just 363 00:20:29,880 --> 00:20:33,440 Speaker 1: in other versions of the universe. But that doesn't make 364 00:20:33,560 --> 00:20:35,679 Speaker 1: all the versions of the universe equal or on the 365 00:20:35,720 --> 00:20:38,840 Speaker 1: same footing. Because I'm in this one, you know, this 366 00:20:38,960 --> 00:20:41,159 Speaker 1: is the one that I feel is the truth that 367 00:20:41,280 --> 00:20:44,000 Speaker 1: I'm making the measurement in. And that's different from the 368 00:20:44,000 --> 00:20:46,159 Speaker 1: other ones because I'm not in those other ones. And 369 00:20:46,160 --> 00:20:48,439 Speaker 1: maybe there are other means in the other ones. And 370 00:20:48,560 --> 00:20:51,320 Speaker 1: let's say that they're you know who I actually am. 371 00:20:51,400 --> 00:20:53,199 Speaker 1: But this is the one that I'm experiencing, and so 372 00:20:53,240 --> 00:20:56,160 Speaker 1: it still feels to me like it has a special place. 373 00:20:56,400 --> 00:20:58,600 Speaker 1: Is that a naive concern or is that something that 374 00:20:58,640 --> 00:21:01,760 Speaker 1: you think many worlds can address. It is a concern 375 00:21:02,359 --> 00:21:05,680 Speaker 1: because about many words plays exactly on the fact that 376 00:21:06,480 --> 00:21:09,639 Speaker 1: there is a contingency in who you are, which is 377 00:21:09,720 --> 00:21:14,840 Speaker 1: hard to making, not either informals or in words, and 378 00:21:15,240 --> 00:21:18,760 Speaker 1: it is left a little bit vague into that. So 379 00:21:19,600 --> 00:21:23,080 Speaker 1: it is a concern that some philosophers have raised about 380 00:21:24,200 --> 00:21:26,800 Speaker 1: about many worlds. All right, Well, as long as philosophers 381 00:21:26,840 --> 00:21:31,760 Speaker 1: agree with me, then i'm solid. Okay, Yeah, but you know, 382 00:21:31,960 --> 00:21:35,840 Speaker 1: you can always find a philosopher that has a low 383 00:21:35,880 --> 00:21:39,560 Speaker 1: bar apparently. All right, so that's the many worlds interpretation. 384 00:21:39,840 --> 00:21:41,720 Speaker 1: Let's go to the cobanagen which is what you said 385 00:21:41,760 --> 00:21:44,760 Speaker 1: at school, okay, The communities says, well, there are special 386 00:21:44,760 --> 00:21:50,440 Speaker 1: things which observers, okay, which are classical, namely a big, 387 00:21:50,840 --> 00:21:54,960 Speaker 1: big compared to to the quantum phenomena. It's when you 388 00:21:55,000 --> 00:21:58,359 Speaker 1: don't see quantum phenomena because they're too subtle for you. 389 00:21:58,440 --> 00:22:00,800 Speaker 1: They are not visible to you there because you're too 390 00:22:00,840 --> 00:22:03,760 Speaker 1: heavy to see quant phenomena. To isolate things, you go 391 00:22:03,880 --> 00:22:06,600 Speaker 1: to small things, so they are classical ob genia many 392 00:22:06,880 --> 00:22:09,120 Speaker 1: all the ones around us, and there is a classical 393 00:22:09,160 --> 00:22:12,359 Speaker 1: So forget quantum mechanics. About this. When a quantum system 394 00:22:12,440 --> 00:22:17,400 Speaker 1: interacts with the classical world, bingo, that's a measurement. And 395 00:22:17,760 --> 00:22:22,199 Speaker 1: this works in practice very well. That's what we do 396 00:22:22,240 --> 00:22:25,560 Speaker 1: in the laboratory. But in theory it obviously does not 397 00:22:25,680 --> 00:22:28,960 Speaker 1: work because what is a classical system? But we I 398 00:22:29,080 --> 00:22:32,440 Speaker 1: am many electrons and protons, and each one of them 399 00:22:32,600 --> 00:22:35,240 Speaker 1: it's a quantum particle, so each one has a wave, 400 00:22:35,400 --> 00:22:37,800 Speaker 1: so I have a big wave. I am a quantum 401 00:22:37,840 --> 00:22:43,479 Speaker 1: system in a sense copenagen it's a works with an 402 00:22:43,480 --> 00:22:47,840 Speaker 1: approximation saying, well, imagine that your theory is wrong for 403 00:22:48,040 --> 00:22:51,119 Speaker 1: big things, forget about it, and still use it for 404 00:22:51,280 --> 00:22:54,719 Speaker 1: small fixed And you know that's why it appeals to 405 00:22:54,800 --> 00:22:58,400 Speaker 1: everybody who does not want to ask questions. And you can, 406 00:22:58,920 --> 00:23:01,120 Speaker 1: but if you don't ask sans, you don't get answers. 407 00:23:01,160 --> 00:23:03,879 Speaker 1: I mean, on those sides of scientists about asking questions, 408 00:23:04,400 --> 00:23:06,120 Speaker 1: A lot of scientists who say, as well, I don't 409 00:23:06,119 --> 00:23:08,639 Speaker 1: want to care about that. There were more in the past, 410 00:23:08,920 --> 00:23:11,879 Speaker 1: in the sixties and the seventies, in the eighties, I 411 00:23:11,880 --> 00:23:15,200 Speaker 1: would say the majority of physicists would have said, oh, 412 00:23:15,240 --> 00:23:17,360 Speaker 1: come on, just use the theory. It works very well. 413 00:23:18,200 --> 00:23:20,320 Speaker 1: Nowadays there are less and less people who do that, 414 00:23:20,520 --> 00:23:24,040 Speaker 1: so I would say the large majority of people agree 415 00:23:24,119 --> 00:23:26,480 Speaker 1: that there is something to say better here. So let's 416 00:23:26,480 --> 00:23:29,639 Speaker 1: come to relationship quantum mechanics. What does the relational quantum 417 00:23:29,680 --> 00:23:33,680 Speaker 1: mechanics says about that? It says that all systems are quantum, 418 00:23:33,840 --> 00:23:38,880 Speaker 1: and that's the first assumption. Let's see that we're, as 419 00:23:38,880 --> 00:23:40,760 Speaker 1: far as we know, quantum mechanics the best ecup, but 420 00:23:40,840 --> 00:23:43,920 Speaker 1: we haven't about the world. So after to disconfirm all 421 00:23:43,960 --> 00:23:47,119 Speaker 1: systems have led to So that's already in contradiction with 422 00:23:47,200 --> 00:23:50,040 Speaker 1: Copenhagen interpretation that says like I am classical and you 423 00:23:50,080 --> 00:23:53,000 Speaker 1: are classical. It says everything is made of quantum. Even 424 00:23:53,040 --> 00:23:56,399 Speaker 1: classical objects are just like massive quantum objects. This is 425 00:23:56,440 --> 00:24:00,000 Speaker 1: just what quantum objects look like when they're really big, exactly. 426 00:24:00,160 --> 00:24:02,520 Speaker 1: So therefore there is nothing which is an observer, but 427 00:24:02,640 --> 00:24:06,640 Speaker 1: by itself, nothing that separates an observer in the sense 428 00:24:06,640 --> 00:24:11,200 Speaker 1: of quantum mechanics from a piece of stone. Of course, 429 00:24:11,720 --> 00:24:16,680 Speaker 1: you know, there the people who have eyes, the machines, 430 00:24:16,840 --> 00:24:21,040 Speaker 1: there are things that store information, but that's irrelevant here. 431 00:24:21,160 --> 00:24:24,600 Speaker 1: The point is in a relational quantum mechanics. That's the 432 00:24:24,640 --> 00:24:28,720 Speaker 1: suggestion of relational quantum mechanics that the measurement happens in 433 00:24:28,760 --> 00:24:34,080 Speaker 1: some sense every time two systems interact. But the actual 434 00:24:34,560 --> 00:24:37,639 Speaker 1: element of reality which is realized in the interaction, so 435 00:24:37,680 --> 00:24:41,359 Speaker 1: that when the detector clicks or the particle is here 436 00:24:41,600 --> 00:24:45,400 Speaker 1: is here because they see here, the particle hits another particle, 437 00:24:45,440 --> 00:24:48,199 Speaker 1: and therefore it has a specific position that has to 438 00:24:48,240 --> 00:24:53,080 Speaker 1: be soked, not as a property of the particle by itself, 439 00:24:53,520 --> 00:24:56,760 Speaker 1: but as a proper relational property of the particle and 440 00:24:57,080 --> 00:25:00,639 Speaker 1: the system it is interacting with in relation to the 441 00:25:00,640 --> 00:25:03,720 Speaker 1: thing during the measurement, exactly innovation to the same door 442 00:25:03,760 --> 00:25:05,520 Speaker 1: and literally which could be anything. We can be another 443 00:25:05,520 --> 00:25:09,840 Speaker 1: party in a sense. So therefore, the central idea of 444 00:25:10,480 --> 00:25:13,840 Speaker 1: religion wanto mechanics is, let's be radical in the following sense. 445 00:25:14,080 --> 00:25:17,520 Speaker 1: We describe the world in terms of systems, particle, electron, 446 00:25:17,880 --> 00:25:22,480 Speaker 1: et cetera. And these have the properties variables that describe them, 447 00:25:22,520 --> 00:25:26,480 Speaker 1: But these variables don't describe how the system is, it interacts, 448 00:25:26,480 --> 00:25:29,280 Speaker 1: how the system interact with something else. Okay, so for example, 449 00:25:29,320 --> 00:25:32,080 Speaker 1: we have a particle and it's flying along and it 450 00:25:32,160 --> 00:25:34,440 Speaker 1: has a certain way function for things that might do, 451 00:25:34,960 --> 00:25:39,840 Speaker 1: and Copenhagen interpretation says it stays probabilistic until something classical 452 00:25:39,920 --> 00:25:43,880 Speaker 1: interact with it. Relation or quantum mechanics says it can 453 00:25:43,920 --> 00:25:47,119 Speaker 1: collapse when it interacts with anything, but that collapse is 454 00:25:47,160 --> 00:25:49,680 Speaker 1: different for depending on who is interacting with it. So 455 00:25:49,720 --> 00:25:52,160 Speaker 1: if it interacts with this particle might collapse in this way. 456 00:25:52,160 --> 00:25:54,320 Speaker 1: If it interacts with somebody else, that might collapse in 457 00:25:54,359 --> 00:25:56,679 Speaker 1: another way. In that sense, it's also sort of like 458 00:25:56,840 --> 00:26:00,119 Speaker 1: a branching of what reality is real, because what is 459 00:26:00,160 --> 00:26:02,600 Speaker 1: real now depends on who is doing the measurement. Is 460 00:26:02,640 --> 00:26:05,760 Speaker 1: that right? That's exactly correct. So the so called collapse 461 00:26:05,800 --> 00:26:08,639 Speaker 1: of the way function is by itself, something which is 462 00:26:09,040 --> 00:26:13,639 Speaker 1: relative to the system against which the particles is interacting, 463 00:26:13,920 --> 00:26:17,400 Speaker 1: which doesn't need to be a macroscopical object, doesn't need 464 00:26:17,480 --> 00:26:22,920 Speaker 1: to be anything special. It's anything but this. The subtlety 465 00:26:23,119 --> 00:26:25,879 Speaker 1: is the following. I suppose the particle interact with my machine, 466 00:26:25,920 --> 00:26:31,119 Speaker 1: my detector, okay, and I am I am a distance 467 00:26:32,040 --> 00:26:35,160 Speaker 1: and the two are not interacting with me. So with 468 00:26:35,240 --> 00:26:40,000 Speaker 1: respect to me, there is no collapse happening. So the 469 00:26:40,119 --> 00:26:44,440 Speaker 1: way the particle and the machine are gonna manifest themselves 470 00:26:44,440 --> 00:26:47,720 Speaker 1: to me later on if they interact with me is 471 00:26:47,760 --> 00:26:50,840 Speaker 1: still computed with quantum mechanics. So if I want to 472 00:26:50,880 --> 00:26:54,320 Speaker 1: compute what happens with respect to me, I still use 473 00:26:54,400 --> 00:26:57,119 Speaker 1: the way function of the particle and the way function 474 00:26:57,160 --> 00:27:00,240 Speaker 1: of the machine, because the machine is quite mechanical, I think. 475 00:27:00,280 --> 00:27:03,200 Speaker 1: So for example, I'm here talking to you, so I'm 476 00:27:03,359 --> 00:27:06,720 Speaker 1: measuring you. I'm collapsing your way function. But our listeners 477 00:27:06,720 --> 00:27:09,120 Speaker 1: have not yet heard this podcast, so from their point 478 00:27:09,119 --> 00:27:11,840 Speaker 1: of view, you and I are still in some uncollapsed 479 00:27:11,960 --> 00:27:15,000 Speaker 1: quantum state, and only when they hear this does it 480 00:27:15,080 --> 00:27:18,120 Speaker 1: collapse into an actual stream of words. So for us 481 00:27:18,600 --> 00:27:21,920 Speaker 1: it is collapsed, but for them it's not yet collapsed exactly. 482 00:27:21,920 --> 00:27:24,000 Speaker 1: So I believe that this is coherent. This can be 483 00:27:24,040 --> 00:27:27,160 Speaker 1: made clearing by going into details. It offers a possible 484 00:27:27,200 --> 00:27:31,119 Speaker 1: solution of the puzzle quantum theory. This is a relation 485 00:27:31,200 --> 00:27:34,680 Speaker 1: with dempetition. It does require it has a cost. There's 486 00:27:34,680 --> 00:27:38,000 Speaker 1: a conceptual cost, because as you said, reality is a 487 00:27:38,040 --> 00:27:42,680 Speaker 1: little bit more subjective. No subjective relative. I'll come back 488 00:27:42,720 --> 00:27:47,080 Speaker 1: to the difference subject in relative. So it weakens realism 489 00:27:47,280 --> 00:27:50,440 Speaker 1: in a sense, but it's still a realistic interpetation. So 490 00:27:50,760 --> 00:27:56,639 Speaker 1: I think that this cost is more worthwhile paying for 491 00:27:57,440 --> 00:28:01,439 Speaker 1: being fruitful for the future of physics than imagining that 492 00:28:01,480 --> 00:28:05,000 Speaker 1: there are many copies of myself, or than not asking 493 00:28:05,000 --> 00:28:07,359 Speaker 1: the question when you come to the subtle team. In 494 00:28:07,440 --> 00:28:10,960 Speaker 1: your example, you talked about you and me and the 495 00:28:11,040 --> 00:28:17,720 Speaker 1: listeners all people. Okay, that's fine, but the key intuition 496 00:28:17,760 --> 00:28:19,720 Speaker 1: of relationship about the mechanics that this has nothing to 497 00:28:19,720 --> 00:28:22,199 Speaker 1: do with people. That's the key point. And that's a 498 00:28:22,240 --> 00:28:26,840 Speaker 1: big difference with respect also with coping again in a sense, right, 499 00:28:26,920 --> 00:28:29,280 Speaker 1: this is nothing to do with subjectivity. That's it to 500 00:28:29,280 --> 00:28:32,239 Speaker 1: do the subject. But factly you and I are are 501 00:28:32,400 --> 00:28:34,720 Speaker 1: subject of perceptions as need to do. You would also 502 00:28:34,760 --> 00:28:39,560 Speaker 1: work if you and I were dogs or bananas or particles, right, exactly, 503 00:28:39,560 --> 00:28:42,440 Speaker 1: the same mathematics work, exactly as I'm the same story 504 00:28:42,480 --> 00:28:45,600 Speaker 1: would work. And to make an example of this, because 505 00:28:45,720 --> 00:28:51,600 Speaker 1: I think that you know, relative to observer observable are 506 00:28:51,640 --> 00:28:57,640 Speaker 1: often misinterpreted as subjective while it's just relational. For instance, 507 00:28:57,840 --> 00:29:01,600 Speaker 1: there's a very well known example of relational notion in 508 00:29:01,680 --> 00:29:06,320 Speaker 1: physics which students struggle at the beginning when they encounter 509 00:29:06,400 --> 00:29:09,160 Speaker 1: it the first time, because it's very contin intuitive if 510 00:29:09,200 --> 00:29:11,160 Speaker 1: you think at the beginning, which is velocity. When we 511 00:29:11,200 --> 00:29:17,600 Speaker 1: study Galian theory a Newton theory, we learn that velocity 512 00:29:17,680 --> 00:29:20,920 Speaker 1: is not absolute, velocity is relative. So what is the 513 00:29:21,000 --> 00:29:26,200 Speaker 1: velocity of the moon. Well, depend there's the velocity of 514 00:29:26,200 --> 00:29:28,560 Speaker 1: the moon we respect to this Earth, the velocity of 515 00:29:28,560 --> 00:29:30,760 Speaker 1: the moon we respect to the Sun. The velocity moon 516 00:29:30,840 --> 00:29:33,920 Speaker 1: we respect to the center of the galaxy, the loscy 517 00:29:33,920 --> 00:29:38,360 Speaker 1: moon respect to the cosmic microwave background average. Which one 518 00:29:38,400 --> 00:29:43,200 Speaker 1: is the true one? Well, no, it's a velocity. It's 519 00:29:43,240 --> 00:29:46,240 Speaker 1: a notion that pertains the two objects, the moon and 520 00:29:46,320 --> 00:29:49,040 Speaker 1: something else. It's always velocity of the moon with respects 521 00:29:49,080 --> 00:29:51,680 Speaker 1: something else. We sort of know that, right, because when 522 00:29:51,720 --> 00:29:55,320 Speaker 1: we say don't move, we know that don't move is 523 00:29:55,400 --> 00:29:58,400 Speaker 1: relativitally to something. For instance, if you're in a train 524 00:29:59,480 --> 00:30:02,200 Speaker 1: and your little daughter is jumping around and you say 525 00:30:02,240 --> 00:30:04,880 Speaker 1: don't move, you don't mean that you little daughters to 526 00:30:05,040 --> 00:30:07,080 Speaker 1: jump out of the train and don't cove with respect 527 00:30:07,120 --> 00:30:11,160 Speaker 1: to the earth. Right, you mean don't move respect to 528 00:30:11,240 --> 00:30:14,400 Speaker 1: the train. And she understand correctly right that she should 529 00:30:14,400 --> 00:30:17,200 Speaker 1: soon move respect the train and she's just still moving 530 00:30:17,280 --> 00:30:20,240 Speaker 1: very fast because the train is running. So we understand 531 00:30:20,360 --> 00:30:24,240 Speaker 1: that velocities are it's it's a relational notion. But this 532 00:30:24,360 --> 00:30:26,680 Speaker 1: is nothing to do with subjectivity, right because if I 533 00:30:26,760 --> 00:30:29,160 Speaker 1: say that the moon has a velocity respect to the sound, 534 00:30:29,880 --> 00:30:33,200 Speaker 1: I'm not saying that the Sun is a subject that 535 00:30:33,320 --> 00:30:35,920 Speaker 1: sees the moon and perceives something. Is nothing to do 536 00:30:35,960 --> 00:30:39,720 Speaker 1: with that, nothing to do with mind subjectivity, Just physics, 537 00:30:39,840 --> 00:30:44,840 Speaker 1: pure physics. There is a quantity to velocity which doesn't 538 00:30:44,840 --> 00:30:47,280 Speaker 1: depend on one thing. It depends on two things, the 539 00:30:47,320 --> 00:30:50,480 Speaker 1: Moon and the Sun. And it's velocity the relative velocity 540 00:30:50,480 --> 00:30:52,160 Speaker 1: of the two, say how they move respect one of that. 541 00:30:52,440 --> 00:30:54,760 Speaker 1: So that's a big philosophical step, right, You've sort of 542 00:30:54,760 --> 00:30:57,320 Speaker 1: taken away from the moon the fact that it can 543 00:30:57,360 --> 00:30:59,920 Speaker 1: have a property called velocity. Say, you can't have a 544 00:31:00,000 --> 00:31:02,719 Speaker 1: property called velocity. Only a pair of things can have 545 00:31:02,800 --> 00:31:06,160 Speaker 1: this property. A single object cannot. And the sort of 546 00:31:06,320 --> 00:31:08,320 Speaker 1: the mental game i'd like to place to imagine, like 547 00:31:08,360 --> 00:31:11,600 Speaker 1: a particle in an empty universe, can it have a velocity? Well, 548 00:31:11,680 --> 00:31:13,480 Speaker 1: it has no meaning to have a velocity if you 549 00:31:13,480 --> 00:31:16,200 Speaker 1: are the only thing in the universe, right, And so 550 00:31:16,520 --> 00:31:18,840 Speaker 1: I want to also ask you about this concept of cost. 551 00:31:18,960 --> 00:31:21,080 Speaker 1: You're talking about the cost of a theory, and so 552 00:31:21,200 --> 00:31:22,960 Speaker 1: here is that the cost you mean that you're like 553 00:31:23,360 --> 00:31:26,760 Speaker 1: now changing philosophically what it means to be real that 554 00:31:26,800 --> 00:31:28,880 Speaker 1: no longer can you include in your sort of you know, 555 00:31:29,040 --> 00:31:32,320 Speaker 1: category or your index of what it means to be 556 00:31:32,600 --> 00:31:35,080 Speaker 1: that you have a certain velocity that you've like taken 557 00:31:35,080 --> 00:31:37,680 Speaker 1: that away from objects. Yes, this is the course, and 558 00:31:38,000 --> 00:31:41,120 Speaker 1: I think you said it very cleanly. It's a deep 559 00:31:41,120 --> 00:31:45,480 Speaker 1: philosophical point when we realize that velocity is not a 560 00:31:45,560 --> 00:31:48,240 Speaker 1: property of an object you need another object, is a 561 00:31:48,280 --> 00:31:52,280 Speaker 1: property of two objects. A quantum mechanics in a sense. 562 00:31:52,520 --> 00:31:54,760 Speaker 1: The phone suggestion that we in this em better quantum 563 00:31:54,760 --> 00:32:00,200 Speaker 1: mechanics if we just interpreted all properties, all variable in 564 00:32:00,240 --> 00:32:05,800 Speaker 1: this way, not just velocity. Okay, any variablity, even think 565 00:32:05,880 --> 00:32:11,280 Speaker 1: about a system only makes sense if you if you 566 00:32:11,320 --> 00:32:14,320 Speaker 1: have another system. You're saying it's this is a variable 567 00:32:14,360 --> 00:32:16,480 Speaker 1: with suspect to this other system. And what you mean 568 00:32:16,560 --> 00:32:18,800 Speaker 1: is that there was an interaction to these two systems 569 00:32:19,040 --> 00:32:23,280 Speaker 1: and that variable was realized in this interaction. Namely, describe 570 00:32:23,360 --> 00:32:25,760 Speaker 1: the way one system affected the other one. And can't 571 00:32:25,760 --> 00:32:27,760 Speaker 1: you use even the same language. Because now we talked 572 00:32:27,760 --> 00:32:31,000 Speaker 1: about velocity. We say velocity of the moon as measured 573 00:32:31,040 --> 00:32:33,040 Speaker 1: by an observer on the Sun, or as measured by 574 00:32:33,080 --> 00:32:36,240 Speaker 1: observer on the Earth. Now you can say the location 575 00:32:36,280 --> 00:32:38,720 Speaker 1: of this particle or the color of this particle as 576 00:32:38,760 --> 00:32:43,120 Speaker 1: measured by this observer versus as measured by that observer exactly. 577 00:32:56,080 --> 00:32:59,440 Speaker 1: Now you went strongly in saying, does this mean that 578 00:32:59,560 --> 00:33:06,360 Speaker 1: reality itself it's relative to um? I hesitate. Namely, the 579 00:33:06,600 --> 00:33:12,360 Speaker 1: same reaction could have been raised against the Galileo and 580 00:33:12,520 --> 00:33:17,959 Speaker 1: Newton when they started using velocity. In this sense, I 581 00:33:18,000 --> 00:33:21,240 Speaker 1: think that the reality of the motion of the moon 582 00:33:21,320 --> 00:33:24,480 Speaker 1: and velocity of the moon and the Sun and things, 583 00:33:24,600 --> 00:33:28,480 Speaker 1: in spite of what we have understood about relativity velocity 584 00:33:28,600 --> 00:33:31,640 Speaker 1: is still very solid. Still we still have a realistic 585 00:33:32,080 --> 00:33:36,560 Speaker 1: interpretation of motion, and so I would like to think 586 00:33:36,560 --> 00:33:41,480 Speaker 1: about relational quantum mechanics as a realistic picture. So reality 587 00:33:41,520 --> 00:33:44,880 Speaker 1: is there, it's I mean, things are there, and then 588 00:33:44,920 --> 00:33:47,200 Speaker 1: there's nothing to do with us. Of course, we are 589 00:33:47,280 --> 00:33:49,080 Speaker 1: just a part of nature. Is not that nature is 590 00:33:49,120 --> 00:33:53,960 Speaker 1: a part of our mind. That's my naturalism if you want. 591 00:33:54,240 --> 00:33:57,560 Speaker 1: But the way reality is is subtle. According to quantum 592 00:33:57,600 --> 00:34:01,480 Speaker 1: mechanics can be described. Reality can be described by systems 593 00:34:01,520 --> 00:34:05,560 Speaker 1: that have a properties relative to other systems. So then 594 00:34:05,680 --> 00:34:09,040 Speaker 1: can you have something which exists by itself like imagine, 595 00:34:09,200 --> 00:34:11,440 Speaker 1: you know, the sort of simple example I mentioned earlier. 596 00:34:11,440 --> 00:34:14,840 Speaker 1: For velocity, a single particle an empty universe can't have 597 00:34:14,880 --> 00:34:18,080 Speaker 1: a velocity. Now you said that everything is relation on 598 00:34:18,120 --> 00:34:20,840 Speaker 1: the way velocity is. Does that mean a single particle 599 00:34:21,120 --> 00:34:24,560 Speaker 1: in an empty universe does not exist or cannot have 600 00:34:24,600 --> 00:34:27,560 Speaker 1: any properties because it would need something else in order 601 00:34:27,600 --> 00:34:30,600 Speaker 1: to measure it. Can a single particle universe exists? No, 602 00:34:30,880 --> 00:34:33,760 Speaker 1: if quantum mechanics max is the correct description of the units. 603 00:34:33,960 --> 00:34:35,720 Speaker 1: And in fact that can be said in a beside 604 00:34:35,719 --> 00:34:38,759 Speaker 1: the way. There's a philosopher which is Madorato who is 605 00:34:39,080 --> 00:34:43,440 Speaker 1: elaborated much on that, saying, if we take relationhp quantum 606 00:34:43,400 --> 00:34:46,080 Speaker 1: mechanics correctly, we cannot talk about the quantum state of 607 00:34:46,120 --> 00:34:49,200 Speaker 1: the universe. We cannot state of the quantum state of everything. 608 00:34:50,040 --> 00:34:53,560 Speaker 1: We cannot even talk about the description of the universe 609 00:34:53,719 --> 00:34:57,160 Speaker 1: because the scripture universe needs to be if you use 610 00:34:57,239 --> 00:34:59,880 Speaker 1: this way of thinking, a point of mechanics scripture relatively 611 00:34:59,880 --> 00:35:02,080 Speaker 1: to something else. So in the moment in which you're 612 00:35:02,160 --> 00:35:05,359 Speaker 1: saying the description units, so you're assuming there is something 613 00:35:05,400 --> 00:35:08,160 Speaker 1: outside that is looking at the universe. Well you can, 614 00:35:08,520 --> 00:35:10,920 Speaker 1: but then in your reality there is something else in 615 00:35:10,960 --> 00:35:13,680 Speaker 1: addition to what you just called the universe a moment ago. 616 00:35:14,000 --> 00:35:17,520 Speaker 1: For instance, the famous way functional units, what is it 617 00:35:17,560 --> 00:35:22,319 Speaker 1: is a mathematical object that allows you to predict what 618 00:35:22,440 --> 00:35:25,160 Speaker 1: you would measure if you are outside the universe to 619 00:35:25,280 --> 00:35:28,280 Speaker 1: interact with it. But then it's not the universe anymore 620 00:35:28,320 --> 00:35:30,839 Speaker 1: because there is something else outside the universe interacting with it. 621 00:35:31,760 --> 00:35:35,520 Speaker 1: So there's the way functional use is meaningless. It's always 622 00:35:35,520 --> 00:35:38,880 Speaker 1: the way function of something. I was hoping to use 623 00:35:38,960 --> 00:35:41,120 Speaker 1: that example to lead you down the garden path to 624 00:35:41,200 --> 00:35:43,480 Speaker 1: admit that means the universe can't exist, but you just 625 00:35:43,520 --> 00:35:47,399 Speaker 1: went straight there and said, if this is true, then 626 00:35:47,760 --> 00:35:51,359 Speaker 1: we don't have a meaningful concept of what the universe is. 627 00:35:51,440 --> 00:35:53,600 Speaker 1: I mean, isn't that a problem? I mean, if we 628 00:35:53,640 --> 00:35:56,400 Speaker 1: want a theory of reality that tells us what is happening, 629 00:35:56,719 --> 00:35:59,239 Speaker 1: doesn't it need to also allow us to think about 630 00:35:59,239 --> 00:36:02,520 Speaker 1: what reality is. I think that it's a deeper point 631 00:36:03,160 --> 00:36:06,240 Speaker 1: one of the things we have understood more and more 632 00:36:06,280 --> 00:36:09,760 Speaker 1: in modern physics, but also another realm of modern culture 633 00:36:10,560 --> 00:36:13,640 Speaker 1: is that we're always part of the story. So we 634 00:36:13,719 --> 00:36:17,320 Speaker 1: see reality from we think, not from outside in completely 635 00:36:17,360 --> 00:36:20,360 Speaker 1: different parts of our culture. First this this was famously 636 00:36:20,760 --> 00:36:23,920 Speaker 1: an immense issue and toropology, right, you want to describe 637 00:36:23,960 --> 00:36:26,800 Speaker 1: a society. When the Europeans went around the world to 638 00:36:26,880 --> 00:36:33,440 Speaker 1: try to describe societies objectively, um, non European societies, maybe 639 00:36:33,480 --> 00:36:36,560 Speaker 1: I don't know some people in their matson and then 640 00:36:36,600 --> 00:36:40,120 Speaker 1: they re allies that they were not doing nothing objectively. 641 00:36:40,239 --> 00:36:42,680 Speaker 1: They were just comparing their own culture with the culture 642 00:36:42,680 --> 00:36:45,560 Speaker 1: of these people. In some of they were interacting with 643 00:36:45,640 --> 00:36:49,920 Speaker 1: these people and not being outside a cultural scheme, but 644 00:36:50,880 --> 00:36:55,800 Speaker 1: doing something and olmously interesting, not something that lacked value, 645 00:36:56,360 --> 00:37:00,680 Speaker 1: but that was not a stepping out from what is 646 00:37:00,920 --> 00:37:04,839 Speaker 1: being described. And I think physics to some extent has 647 00:37:04,960 --> 00:37:09,680 Speaker 1: encountered the same set of problems. Namely, we described the 648 00:37:09,760 --> 00:37:12,160 Speaker 1: universe from within. We are part of the universe. What 649 00:37:12,360 --> 00:37:17,000 Speaker 1: physics tell us is if I encounter this, I know 650 00:37:17,440 --> 00:37:21,080 Speaker 1: what I can expect, and I know what a what 651 00:37:21,200 --> 00:37:23,719 Speaker 1: I can expect, what kind of things aide around me. 652 00:37:24,719 --> 00:37:28,000 Speaker 1: But the idea that physics give a list of all 653 00:37:28,160 --> 00:37:32,080 Speaker 1: or everything existing with the state, it's a first of all, 654 00:37:32,200 --> 00:37:36,240 Speaker 1: totally unplausible by itself, right, I mean, how many stars 655 00:37:36,360 --> 00:37:39,160 Speaker 1: there are in the universe, and how many atoms in 656 00:37:39,200 --> 00:37:42,080 Speaker 1: each one of these stars? So it's just totally outside 657 00:37:42,120 --> 00:37:45,319 Speaker 1: or a capacity. But even in principle, what does it mean. 658 00:37:45,640 --> 00:37:48,680 Speaker 1: I mean, physics is all in the form if this, 659 00:37:48,880 --> 00:37:52,839 Speaker 1: then that, right, If I found this pendulum in this way, 660 00:37:53,000 --> 00:37:56,320 Speaker 1: then it's going to move that like that. It's model, 661 00:37:56,440 --> 00:37:59,800 Speaker 1: as the philosopher says. So it's always a story of 662 00:38:00,040 --> 00:38:03,520 Speaker 1: out given some initial conditions, this is what I expect 663 00:38:03,680 --> 00:38:07,280 Speaker 1: to happen, given some data, this is what comes later, 664 00:38:07,560 --> 00:38:09,600 Speaker 1: and then it tells what kind of atoms are around, 665 00:38:09,600 --> 00:38:12,880 Speaker 1: the forces are around. But we shouldn't expect from physics 666 00:38:13,280 --> 00:38:17,000 Speaker 1: the total novel of the universe. That's what everything is 667 00:38:17,040 --> 00:38:19,400 Speaker 1: in the universe. That's at all the state of the universe. 668 00:38:20,560 --> 00:38:24,920 Speaker 1: Why it's not that's far outside our capacities, And probably 669 00:38:26,120 --> 00:38:30,000 Speaker 1: I would say it's meaningless because of what we said before, 670 00:38:30,040 --> 00:38:33,560 Speaker 1: because that would be an issue that God might have 671 00:38:33,840 --> 00:38:37,279 Speaker 1: if he or she exists seeing from the units from 672 00:38:37,320 --> 00:38:39,680 Speaker 1: the outside, not of all our business. And I think 673 00:38:39,760 --> 00:38:42,760 Speaker 1: this makes exactly the point that you were talking about earlier, 674 00:38:43,040 --> 00:38:45,960 Speaker 1: that we want to know the answers these the philosophical questions, 675 00:38:45,960 --> 00:38:49,040 Speaker 1: because they tell us which questions then makes sense to 676 00:38:49,239 --> 00:38:52,479 Speaker 1: ask which questions have answers, and which questions are even 677 00:38:52,520 --> 00:38:54,960 Speaker 1: relevant to think about. I think that's some of the 678 00:38:54,960 --> 00:38:58,560 Speaker 1: most important reason why physicists need to think about philosophy. 679 00:38:58,719 --> 00:39:00,799 Speaker 1: And I know that you talked about the mechanics a lot, 680 00:39:00,840 --> 00:39:02,839 Speaker 1: and you're quite an expert on this, So I want 681 00:39:02,840 --> 00:39:04,640 Speaker 1: to try to ask you a question that maybe nobody 682 00:39:04,640 --> 00:39:06,799 Speaker 1: has asked you before, put you on the spot, and 683 00:39:06,800 --> 00:39:08,879 Speaker 1: and that's this. Have you thought about what it might 684 00:39:08,880 --> 00:39:13,960 Speaker 1: be like to talk about physics or quantum mechanics with aliens? 685 00:39:14,400 --> 00:39:18,799 Speaker 1: Imagine that we have meet extraterrestrial physicists, right, and we 686 00:39:19,000 --> 00:39:20,960 Speaker 1: go and we we say with to them whole you 687 00:39:21,040 --> 00:39:23,080 Speaker 1: must know the secrets of the universe because you figured 688 00:39:23,120 --> 00:39:25,239 Speaker 1: out how to travel here from distant stars. Do you 689 00:39:25,239 --> 00:39:28,120 Speaker 1: think there's any possibility that we would be asking the 690 00:39:28,160 --> 00:39:31,799 Speaker 1: same questions or that their answers to our questions would 691 00:39:31,840 --> 00:39:33,880 Speaker 1: make any sense to us. Do you think that the 692 00:39:33,920 --> 00:39:35,800 Speaker 1: way that we look at the universe is sort of 693 00:39:35,840 --> 00:39:39,200 Speaker 1: the way Europeans, you know, looked at other cultures. Do 694 00:39:39,239 --> 00:39:41,960 Speaker 1: you think that's deeply imbued with our human bias, or 695 00:39:41,960 --> 00:39:44,919 Speaker 1: do you think that we are probing something universal which 696 00:39:44,920 --> 00:39:47,680 Speaker 1: should be part of sort of like some galactic physics project. 697 00:39:47,880 --> 00:39:49,960 Speaker 1: Great question. A bit of both, but more of the 698 00:39:49,960 --> 00:39:52,560 Speaker 1: first and the second. That's my answer. There is a 699 00:39:52,600 --> 00:39:55,719 Speaker 1: precise sense in which what we discover in science is 700 00:39:55,920 --> 00:39:59,080 Speaker 1: it's just two in universal mean. I don't think this 701 00:39:59,120 --> 00:40:02,279 Speaker 1: can be denied, and people who denied it, I think 702 00:40:02,320 --> 00:40:05,279 Speaker 1: have a toak way of denying it, and don and 703 00:40:05,280 --> 00:40:08,280 Speaker 1: physics in some sense, it's true. It works described reality. 704 00:40:08,280 --> 00:40:11,640 Speaker 1: It's I mean, the fact that everything is made by 705 00:40:11,680 --> 00:40:15,400 Speaker 1: atoms and there are ninety and so kind of different atoms. 706 00:40:15,440 --> 00:40:18,399 Speaker 1: That's a fact. It's like when you you know, when 707 00:40:18,440 --> 00:40:21,080 Speaker 1: you go down the street and you see that you 708 00:40:21,120 --> 00:40:24,360 Speaker 1: know your three friends are in the cafe. That's a fact. 709 00:40:24,600 --> 00:40:28,240 Speaker 1: It's true. And I believe that science is a higher 710 00:40:28,320 --> 00:40:33,480 Speaker 1: level of understanding. Fact is the way humankind organizes an 711 00:40:33,600 --> 00:40:38,279 Speaker 1: understanding of reality better and better. But from this, to 712 00:40:38,440 --> 00:40:43,200 Speaker 1: have the idea that there is a unique, clearly path 713 00:40:43,320 --> 00:40:46,359 Speaker 1: to the perfect description of reality and we are on need, 714 00:40:46,640 --> 00:40:48,840 Speaker 1: or even that we're close to the end of it, 715 00:40:49,600 --> 00:40:54,600 Speaker 1: that seems to me unbelievably full of self pretension, and 716 00:40:54,840 --> 00:40:58,880 Speaker 1: I see no sign that we're close to that. And 717 00:40:59,360 --> 00:41:01,680 Speaker 1: we have a sort of experiment of that because we 718 00:41:02,200 --> 00:41:07,680 Speaker 1: know what asked centurists, scientists thought, and we do know 719 00:41:07,719 --> 00:41:10,040 Speaker 1: that some of the things that we know would be 720 00:41:10,080 --> 00:41:14,480 Speaker 1: meaningless for them, It would not answer their questions in 721 00:41:15,080 --> 00:41:17,920 Speaker 1: really going in a different direction, which does not mean 722 00:41:17,960 --> 00:41:19,920 Speaker 1: that they are better than us. We are better than 723 00:41:19,960 --> 00:41:24,200 Speaker 1: them because we know what they are in some objective sense, 724 00:41:24,239 --> 00:41:27,480 Speaker 1: and the objective sense is that if both one came alive, 725 00:41:27,800 --> 00:41:30,040 Speaker 1: and if I could have enough time also want to 726 00:41:30,040 --> 00:41:32,840 Speaker 1: me sitting here, I believe that I could slowly arrive 727 00:41:32,880 --> 00:41:34,800 Speaker 1: to convince him that there are a lot of interesting 728 00:41:34,840 --> 00:41:36,520 Speaker 1: things he doesn't know. So I think it's the same 729 00:41:36,560 --> 00:41:40,120 Speaker 1: with some aliens. If some millions would come, I wouldn't 730 00:41:40,120 --> 00:41:42,560 Speaker 1: be surprised if they have a completely different story. And 731 00:41:42,640 --> 00:41:44,600 Speaker 1: it might be possible that we just don't understand one 732 00:41:44,600 --> 00:41:48,080 Speaker 1: another because the story is two different. It might be 733 00:41:48,080 --> 00:41:51,439 Speaker 1: different because they have a different way of perceiving reality. Right, 734 00:41:51,520 --> 00:41:53,680 Speaker 1: we view reality on the basis of what useful to 735 00:41:53,719 --> 00:41:56,600 Speaker 1: our They're being an evolution, not on the basis of, 736 00:41:56,680 --> 00:42:00,640 Speaker 1: you know, some contient rationalism or simply even if they 737 00:42:00,680 --> 00:42:04,080 Speaker 1: had the same senses, because culture of them was going 738 00:42:04,120 --> 00:42:08,480 Speaker 1: in other directions. But I believe there is communication, right, 739 00:42:08,520 --> 00:42:14,040 Speaker 1: Cultures communicate, So maybe with this aliens we could learn 740 00:42:14,640 --> 00:42:18,000 Speaker 1: to communicate. And we were very surprised of learning completely 741 00:42:18,040 --> 00:42:20,960 Speaker 1: different perspectives. If they are more advanced than us in 742 00:42:21,040 --> 00:42:24,640 Speaker 1: some sense, or maybe they will be surprised to learn 743 00:42:24,760 --> 00:42:26,879 Speaker 1: something from us, or maybe both. So in other ways, 744 00:42:26,920 --> 00:42:28,480 Speaker 1: I don't think there is a path to tools, and 745 00:42:28,600 --> 00:42:31,400 Speaker 1: they would know everything we know any more. Maybe they 746 00:42:31,440 --> 00:42:33,759 Speaker 1: would never think about quantum mechanics and we teach them 747 00:42:33,800 --> 00:42:38,000 Speaker 1: quanto mechanics. That was fantastic. You're right, it's a relationship. 748 00:42:38,000 --> 00:42:40,359 Speaker 1: But will send you to meet the aliens and how 749 00:42:40,440 --> 00:42:43,360 Speaker 1: they don't eat you. There is a greater novel, The 750 00:42:43,480 --> 00:42:46,520 Speaker 1: Dark Clouds The Black Cloud, in which there is this 751 00:42:47,160 --> 00:42:51,040 Speaker 1: it's a huge cloud that come towards the sermon and 752 00:42:51,239 --> 00:42:55,200 Speaker 1: somebody realizes that it's actually intelligent something down there, and 753 00:42:55,239 --> 00:42:57,520 Speaker 1: it's uh, and somebody realized that it is going to 754 00:42:57,600 --> 00:42:59,880 Speaker 1: be a disaster for the Earth is going to exactly 755 00:43:00,080 --> 00:43:03,759 Speaker 1: edge of the sound. And somehow so the scientists arrived 756 00:43:03,760 --> 00:43:08,200 Speaker 1: to communicate and so gently convinced this cloud to leave 757 00:43:08,280 --> 00:43:12,080 Speaker 1: us alone. But then there is one scientist so too. 758 00:43:12,080 --> 00:43:13,839 Speaker 1: I don't remember. That's the Wait a minute, I want 759 00:43:13,840 --> 00:43:17,359 Speaker 1: to learn everything you know, So the cloud answer, well, 760 00:43:17,960 --> 00:43:22,520 Speaker 1: it's tandrous. I mean your little brain. But they really 761 00:43:22,560 --> 00:43:25,640 Speaker 1: wanted to so they can say, okay, if you really want, so, 762 00:43:25,960 --> 00:43:30,000 Speaker 1: I think it's two of them. They sit around the screen, okay, 763 00:43:30,040 --> 00:43:32,359 Speaker 1: and the screens start flickering, and they just look at 764 00:43:32,400 --> 00:43:34,440 Speaker 1: this at the beginning. At the beginning, they don't understand, 765 00:43:34,480 --> 00:43:38,840 Speaker 1: but then they start understanding, and then finally they start learning, 766 00:43:39,280 --> 00:43:42,239 Speaker 1: and then they're lost because then they're considered fool and 767 00:43:42,280 --> 00:43:45,839 Speaker 1: they're putting all the psychotic hospital and the body knows what. 768 00:43:47,920 --> 00:43:50,360 Speaker 1: That's the danger of talking physics with aliens is you 769 00:43:50,360 --> 00:43:53,040 Speaker 1: can see reality, so clearly the humans can no longer 770 00:43:53,080 --> 00:43:55,279 Speaker 1: relate to you. So let me bring it back to 771 00:43:55,440 --> 00:43:58,840 Speaker 1: one last question about relational quantum mechanics. What you're proposing 772 00:43:58,880 --> 00:44:01,120 Speaker 1: here is really a ratheric of departure on a way 773 00:44:01,160 --> 00:44:05,640 Speaker 1: of seeing the universe, imagining that objects don't contain on 774 00:44:05,719 --> 00:44:09,240 Speaker 1: their own properties, but that these things are just dependent 775 00:44:09,360 --> 00:44:12,319 Speaker 1: on pairs, essentially things that are measuring other things. So 776 00:44:12,440 --> 00:44:14,520 Speaker 1: my question to you is that how could we know 777 00:44:14,600 --> 00:44:17,480 Speaker 1: if this is true. Is there some experiment we can do? 778 00:44:17,520 --> 00:44:20,480 Speaker 1: They could tell us, look, Copenhagen fails here and we 779 00:44:20,520 --> 00:44:23,120 Speaker 1: need relation or quantum mechanics, or we can dispense with 780 00:44:23,160 --> 00:44:25,680 Speaker 1: the many worlds, like is this something which can only 781 00:44:25,719 --> 00:44:29,600 Speaker 1: ever be a philosophical conversation among physicists motivating our questions 782 00:44:29,600 --> 00:44:31,960 Speaker 1: about reality, or is this something we can actually one 783 00:44:32,040 --> 00:44:35,000 Speaker 1: day put to the test. I don't see any way 784 00:44:35,160 --> 00:44:39,000 Speaker 1: it could put to the test. There's some interpretation quantum 785 00:44:39,000 --> 00:44:42,799 Speaker 1: mechanics that assume that quantum mechanics actually wrong, and so 786 00:44:43,440 --> 00:44:45,920 Speaker 1: they can be tested because you can do an experiment 787 00:44:45,960 --> 00:44:47,960 Speaker 1: to see where the quantum mechanic is wrong right, And 788 00:44:48,040 --> 00:44:51,120 Speaker 1: they're very interesting. And so far many of these tests 789 00:44:51,160 --> 00:44:53,600 Speaker 1: have been done and quant mechanics always going to be right, 790 00:44:53,880 --> 00:44:57,040 Speaker 1: and all alternative from the moment have been all eliminated. 791 00:44:57,280 --> 00:45:01,000 Speaker 1: But the various interpretation like many world or de bullyable, 792 00:45:01,160 --> 00:45:04,880 Speaker 1: the pilot wave interpretation, hidden variables or relationship quantum mechanics, 793 00:45:04,960 --> 00:45:08,640 Speaker 1: which I think are the main one. So cubans maybe 794 00:45:08,640 --> 00:45:12,839 Speaker 1: in one sense, they are not distinguishable in an empirical way, 795 00:45:13,040 --> 00:45:14,920 Speaker 1: as as far as I know, nobody has come out 796 00:45:14,960 --> 00:45:18,399 Speaker 1: with experimented distinguished them, and in a sense studying them, 797 00:45:18,719 --> 00:45:22,160 Speaker 1: there's no experiment making a difference, So how would we know, Well, 798 00:45:22,200 --> 00:45:25,359 Speaker 1: I think exactly the same way, which we finally all 799 00:45:25,400 --> 00:45:27,480 Speaker 1: agree that the Earth is not the center of the universe, 800 00:45:28,280 --> 00:45:31,279 Speaker 1: even if there is no experiment that tells us that 801 00:45:31,640 --> 00:45:34,160 Speaker 1: the Earth is or is not the center of the universe, 802 00:45:34,320 --> 00:45:37,960 Speaker 1: because there's no way to measure just what the center 803 00:45:38,800 --> 00:45:43,320 Speaker 1: the center units, namely, the progress of science will work 804 00:45:43,400 --> 00:45:46,400 Speaker 1: better with one conceptual scheme than the other. I do 805 00:45:46,480 --> 00:45:50,239 Speaker 1: quanta gravity my main the reason I got into the 806 00:45:50,320 --> 00:45:54,279 Speaker 1: issue of integrational quantum mechanics, and the mechanic goes back 807 00:45:54,320 --> 00:45:56,680 Speaker 1: to the nineties. In fact, my first papers on that 808 00:45:56,800 --> 00:46:00,040 Speaker 1: in the late nineties, and then other people can and 809 00:46:00,760 --> 00:46:03,360 Speaker 1: have developed it and in recent years have been a 810 00:46:03,880 --> 00:46:08,720 Speaker 1: much stronger increasing interest in it. And it's not isolated 811 00:46:08,800 --> 00:46:11,480 Speaker 1: because there are the people who are very similar ideas, 812 00:46:11,480 --> 00:46:13,960 Speaker 1: So which why is really part of a little group 813 00:46:14,120 --> 00:46:19,960 Speaker 1: of interpretation just similar in some sense, maybe with different emphasis, 814 00:46:20,000 --> 00:46:26,160 Speaker 1: different tone. I'm thinking of writings by Zeilinger, by Chancellor Bruckner, 815 00:46:27,160 --> 00:46:30,640 Speaker 1: by Richard Haley and another. There are a number of 816 00:46:30,800 --> 00:46:33,160 Speaker 1: ways of going in the same direction, so in my 817 00:46:33,200 --> 00:46:35,040 Speaker 1: own work and trying to put up a quantic see 818 00:46:35,080 --> 00:46:38,839 Speaker 1: of gravity, I found that this way of thinking, it's 819 00:46:38,960 --> 00:46:42,680 Speaker 1: much more helpful when you don't have space, you don't 820 00:46:42,719 --> 00:46:45,760 Speaker 1: have time to locate things, you don't have the observer. 821 00:46:46,280 --> 00:46:49,640 Speaker 1: This relational way works well. And one reason it works well, 822 00:46:49,760 --> 00:46:52,760 Speaker 1: it works through well well with general activity, where location 823 00:46:52,840 --> 00:46:56,200 Speaker 1: is relations. Nothing has a position to be somewhere. It's 824 00:46:56,200 --> 00:46:59,680 Speaker 1: only meaningful if you're some well respect to something else. 825 00:46:59,800 --> 00:47:03,920 Speaker 1: And now the things start staying together well, because to 826 00:47:04,120 --> 00:47:07,400 Speaker 1: be next to something is possibility of interacting with something, 827 00:47:07,520 --> 00:47:10,279 Speaker 1: so you can exchange information with something. That's what we're 828 00:47:10,320 --> 00:47:13,360 Speaker 1: talking about in physics, this being next to one another 829 00:47:13,400 --> 00:47:18,239 Speaker 1: and exchanging something, rather than having, you know, it becomevast 830 00:47:18,280 --> 00:47:21,560 Speaker 1: there and placing things and saying that's that's what reality is. 831 00:47:21,760 --> 00:47:25,239 Speaker 1: So I hope that the discussion about indevidual quadema is 832 00:47:25,280 --> 00:47:27,600 Speaker 1: going ahead. It's not blocked, it's not the same as 833 00:47:28,000 --> 00:47:31,280 Speaker 1: thirty years ago. And I think that with the new ideas, 834 00:47:31,320 --> 00:47:34,239 Speaker 1: with the new things being discussed, at some point it 835 00:47:34,320 --> 00:47:37,200 Speaker 1: will become more and more clear that one way of 836 00:47:37,280 --> 00:47:40,840 Speaker 1: viewing things it's productive. It works. It doesn't require us 837 00:47:40,920 --> 00:47:44,360 Speaker 1: to assume things which are absurd, but it does require 838 00:47:44,440 --> 00:47:47,960 Speaker 1: us to assume things which are necessary to make in 839 00:47:48,000 --> 00:47:52,880 Speaker 1: sense of reality. Wonderful. Well, that's a fascinating insight into 840 00:47:53,200 --> 00:47:55,520 Speaker 1: how we might make steps forward. And I agree with 841 00:47:55,560 --> 00:47:58,839 Speaker 1: you that it makes sense to unify quantum mechanics with 842 00:47:59,000 --> 00:48:03,560 Speaker 1: relativity if quantum mechanics itself becomes sort of relativistic, not 843 00:48:03,680 --> 00:48:06,080 Speaker 1: in the sense of things moving at very high speeds, 844 00:48:06,080 --> 00:48:08,360 Speaker 1: but in the sense that the objects and the quantities 845 00:48:08,400 --> 00:48:13,480 Speaker 1: we measure themselves are relational or relative to other objects. 846 00:48:13,600 --> 00:48:15,640 Speaker 1: So that makes a lot of sense. Well, thanks very 847 00:48:15,680 --> 00:48:19,000 Speaker 1: much for this fascinating conversation, really stimulating, you know, about 848 00:48:19,040 --> 00:48:22,719 Speaker 1: quantum mechanics and physics and relativity and of course aliens 849 00:48:22,960 --> 00:48:25,160 Speaker 1: and philosophy. I want to thank you very much, and 850 00:48:25,200 --> 00:48:27,399 Speaker 1: I want to point our listeners to your book Health 851 00:48:27,400 --> 00:48:29,719 Speaker 1: Go Land, which has just come out recently, and it's 852 00:48:29,760 --> 00:48:33,320 Speaker 1: fascinating read on these ideas and how they were developed, 853 00:48:33,440 --> 00:48:35,399 Speaker 1: and people who are interested in digging more deep into 854 00:48:35,440 --> 00:48:38,400 Speaker 1: them might encourage you to check them out. So Carlo, 855 00:48:38,440 --> 00:48:40,839 Speaker 1: thanks you very much for joining us on the program today. 856 00:48:40,880 --> 00:48:51,440 Speaker 1: Thank you. Emaually, that's what's great. Thank you. Thanks for 857 00:48:51,480 --> 00:48:54,400 Speaker 1: listening and remember that Daniel and Jorge explained. The Universe 858 00:48:54,520 --> 00:48:57,839 Speaker 1: is a production of I Heart Radio or more podcast 859 00:48:57,960 --> 00:49:00,640 Speaker 1: for my heart Radio, visit the I Heart a new Apple, 860 00:49:00,880 --> 00:49:04,320 Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows. 861 00:49:06,200 --> 00:49:06,239 Speaker 1: H