Carlo Rovelli, the globally celebrated physicist and bestselling storyteller of science, talks to Niki Seth-Smith about the history, and sheer wonder, of quantum theory. How did a feverish young man named Werner Heisenberg, working alone on the North Sea island of Helgoland in 1925, develop a radical insight that would shake the world of physics? What’s its legacy for how we think about the nature of reality and perception itself? And how might the ‘relational’ interpretation of quantum mechanics transform the way that we might see not only the physical world, but our relationships and politics, too?

A fascinating conversation about collaboration and mentorship, our attachment to truth and certainty, and the humbling power of science.

Podcast listeners can get a year's subscription to New Humanist magazine for just £13.50. Head to newhumanist.org.uk/subscribe and enter the code WITHREASON

Hosts: Niki Seth-Smith and Samira Shackle

Exec producer: Alice Bloch

Sound engineer: David Crackles

Artwork: Christopher Wahl (photograph), Ed Dingli (artwork)

Music: Danosongs

Transcript:

Niki Seth-Smith:

Hi and thanks for joining us here at With Reason from New Humanist magazine. I'm Niki Seth-Smith.

Samira Shackle:

And I'm Samara Shackle, and With Reason is where we talk to exciting critical thinkers about their research and ideas to consider questions of reason and unreason, belief and disbelief, criticism and debate.

NSS:

We’re about philosophy, culture and science. And in this series, we're digging deep with people like the anatomist Alice Roberts, who's written about ancient burials and what they tell us about human life. And we're looking way beyond Planet Earth with the journalist Nick Schmidle, who has written a new book about contemporary space travel. So we're covering a lot of ground.

SS:

Today we're going to hear from a man whose work gets to the very nature of reality itself, the theoretical physicist Carlo Rovelli. And if you were not a fan of physics at school, or it's not something that you've engaged with, stay right where you are. Because Carlo is an absolutely genius at science communication. His books have been translated into dozens of languages. And in 2019, Foreign Policy magazine named him as one of the world's 100 most influential thinkers.

So Niki, you'll be talking to Carlo. And I'll just be listening in in the background. But I know that when I spoke to Alice Roberts recently, she spoke really interestingly about the importance of narrative to science. And I think that's something that Carlo talks about, too, isn't it?

NSS:

Yes, Carlo has been called the poet of physics. And it's clear to see why when you read his work, he has a real gift for bringing science to life. And it's testament to his thirst for a challenge that he set his sights on explaining to the public, what is actually his field of expertise, and maybe the most mind bending field of all: quantum mechanics.

So Carlo notes that the word “quanta” derives in part from the word “grains”. So when I met him, I started by asking him how we can define quantum physics in the most simple way possible. Samira, sit back, enjoy, take notes, and we'll catch up for a chat at the end of the show.

Carlo Rovelli:

Quantum physics is today essentially basic physics: namely, it's the form, the elementary description of nature, the best one we have, the fundamental way we have found today to describe the physical world, how everything works. It’s useful [to understand] atoms and molecules, for things happening in the sun, for computers… It’s not used for cars and aeroplanes, because for cars and aeroplanes one does not need quantum physics, one uses classical physics, which is an approximation to quantum physics. So the older Newtonian physics is still very good. But we use quantum physics in the specific domains where we can’t neglect its peculiarities.

NSS:

You started to talk about some of the practical reasons that we might be using quantum mechanics. Can you go into some specific examples of practical applications?

CR:

As soon as we deal with things which are outside the approximation of classical physics, typically small things like atoms and molecules, but also the microchips of a computer, we need quantum physics. So if you and I can talk now through electronics and computers, this is thanks to little devices that have been designed by engineers and physicists using quantum physics. So quantum physics is all over. It's in all our technology.

Plus, for instance, the basics of chemistry are now understood in terms of how atoms and molecules interact with one another, using quantum physics. So today, we use quantum physics in applications, lasers, photoelectric trials, computers, chips, and so on. We use it for understanding phenomena in the universe, for instance, how the sun works, how is the burning inside the sun happening? It’s not burning, like, like a piece of wood burns, it’s burning of hydrogen into helium. And we understand that phenomenon using quantum physics. It’s a basis of so much of modern technologies, so much of our understanding of the universe. It sort of the best physics has produced so far for understanding the universe. And yet it has a mysterious side.

NSS:

And we'll go into that mysterious side of the science later, but you've said that studying quanta is a psychedelic experience. Can you just say a bit more about why it feels psychedelic to you?

CR:

It is! Perhaps because the Newtonian physics, the physics of Einstein, also Maxwell, Boltzmann, has become very intuitive for us. And it sort of fits this to some extent with our naïve, common sense understanding of the world. Quantum physics is based on a way of describing nature, which is not intuitive, and it looks strange. And it requires us to make some conceptual steps.

Let me tell something more on why it is so strange. In Newtonian physics, we describe how things are. So the typical explanation: you have a stone moving, and then you have some equations that tells you how this stone moves where it goes, which you can compute on the basis of, you know, knowing where it is, and what speed it has. At some moments, the equation tells you “Well, the stone is here, then this stone is there, then the stone is there,” it moves in some way in space-time. And this fits with you know, we see stones falling and it sounds reasonable.

Quantum Physics does not work this way. It works by telling us where we are going to see the stone when we look at it. And it forbids us to think that the stone is always somewhere. So the way you do a calculation, for instance, take a stone moving, is that: imagine you see it somewhere with some precision, or some speed with some precision, and you want to compute where it goes, then you do a calculation. And quantum physics tells you where it's going to go – or more precisely it tells you the probability of finding it here or there. But it doesn't tell you how to get there. It doesn't tell you what this stone does in between. And if you look in the calculation, what you do is to imagine that the stones opens up in a sort of wave, it's all over [the place] and then, when you look at it, it collapses into a point, so to say. And that's very strange, because it seems like the theme is telling us that things are different when we look at them, and when we don't look at them. And that's a mystery. Instead of describing how the world is, it describes how the world manifests itself to us when we interact with it.

NSS:

So that leads on quite nicely to your book, because your latest book tells the story of quantum mechanics beginning in 1925, when a young man named Werner Heisenberg retreated to a windswept Island named Helgoland, which is the name of your book. And it's there that he arrived at that key insight behind quantum mechanics. And you were talking about basing your findings only on what could be observed. And as I understand it, that was the sort of radical idea that Heisenberg came to on that island. Is that correct?

CR:

That's exactly correct. Heisenberg was very young at the time, in his early 20s, he was immersed in the discussion about how to understand atoms, how they work, at the time. But he was also aware of a lot of philosophical discussions about the nature of reality that were going on in Germany and in Europe at the time. And while everybody else was trying to write equations, and imagining forces, that would move electrons and atoms in a way that would make sense of what we see, he took this extraordinary radical step under the influence of some philosophical ideas, of just giving up describing what happens inside the atoms, and in his words, just describe what we observe.

And on the basis of that, he devised some different kinds of mathematics, not the mathematics that describes where the electron is moment by moment, but a mathematics that describes the possible sort of jumps from one observation to the other of the electron. And he says that, in his fundamental article that he wrote in 1925, the article opens by saying: I'm going to do a new form of mechanics, quantum mechanics, which is only based on what we observe. On the one hand, it's mysterious, and on the other hand, spectacularly, it works. Namely, his equations, or more precisely, the equations that he and his colleagues developed in just a month immediately after the first article, are still the equations we use to design a new computer or to understand what happened in the distant star.

NSS:

And that has interesting implications for questions around how we do science. Because we think of science being done in a team. And obviously Heisenberg worked later with, with many people, you say philosophers as well as scientists. But he was really in isolation when he came to this discovery. Can you tell us a little bit more about the island? And was it important that he was isolated there at the time?

CR:

It’s a beautiful story, because science clearly is a collective of the private enterprise. Nobody can do science alone, right. So it's not that Heisenberg created new science from nothing. He was immersed in all the rich and, and very wide knowledge about atoms and ideas that were around. However, they're always these steps, then often a single person or a single small group, sometimes that, that make a step that somehow brings together the different pieces and has a new idea.

And Heisenberg, it's almost a prototype of this, what he did in 1925 – this moment of, I would say, genius taking a step. He went to this island, mainly because of medical reasons, he was suffering from hay fever allergy. And the island has no vegetation. So it's perfect if you want to stay away from pollen that gives an allergic reaction. But I imagine he went there also to be alone, I think. And the islands is, is traditionally considered the hiding place of a famous pirate that kids in Germany loved at the time. So I cannot resist the idea that he was also attracted by this sort of pirate image of solitude in a hiding place. The island is very wild, windswept, with no vegetation.

And so this young guy goes there and spend the time doing calculations. And with a sort of fever, also, because of this allergy, completely immersed into the problem, he tries everything like no other scientists had tried. And then he comes out with his extremely radical ideas, he does his calculation, and the calculation seems to work. Namely, they seem to give exactly the kind of results which were observed in the laboratory. And there are beautiful pages by him about the day specifically in which everything suddenly seems to be working. And he works late in the night and he says he's all excited. So he makes mathematical mistakes in calculation because of his excitement. So he has to work even more late in the night and he gets more and more excited until everything sort of works. And it's three o'clock in the night, he goes out in the island, he climbs the rock, there are big high rocks, and he waits for the sun coming up over the ocean.

He says he was aware that the nature had been so kind to him, to allow him to take a glimpse into some hidden aspects of reality. And he’s the first one to have seen a new a new layer behind the veil of the usual appearances. It's an intense moment. It's a moment in which the key step for unravelling the quantum phenomenon has been taken. He's the only person who has got the Nobel Prize for the invention of quantum mechanics. But still, I think that the theory is so strange that people outside the science community, and even inside the science community, have not yet digested the extreme radicality of the steps taken by Heisenberg, which is a right step for understanding nature: giving up the idea that things always have properties when they are not interacting with anything else.

NSS:

I will come back to how far we've absorbed that idea, even in our own contemporary times. But just for now, I'm sticking with Heisenberg. When he does come back after having this revolutionary experience on the island, can you tell us a bit more about who he works with then? And I think I mean, he was surprisingly young, but I think that that group was also quite young. It was called “boys’ physics” at some point. And I'm interested in that, that there's a group of these surprisingly young men and I think they had a mentor as well. So can we can you tell us a little bit about that maybe and how they were received at the time?

CR:

Yeah, the mentor was older, in his early 40s. All the other kids, namely the in the early 20s Heisenberg, Jordan and Dirac in the UK, and Pauli. Pauli was a friend of Heisenberg’s. And these are the people who put up the theory. I mean, Heisenberg comes back from the island, sort of feeling that he has got something, but also afraid and confused because his ideas were not clear at all. At that point.

He has a draft, he gives a draft to his mentor, this “old man” who's in his 40s, who is Max Born, who was the professor of physics in in Gottingen, where Heisenberg was working. And Max Born – who has a major role in the creation of quantum mechanics, perhaps a role which is still underestimated today I believe – immediately understands and recognises that this is important. And Heisenberg doesn't have the courage to send his calculations to a journal, because it's very confusing. It’s new and strange. I mean, that paper is a very strange paper, and it's completely incomprehensible. But Max Born immediately recognises that the key idea is there and Max Born himself sends the paper of Heisenberg to the journal. It's rapidly published, and Max Born brings together Jordan and Heisenberg and himself and in Gottingen, and they start a furiously to sort of try to clarify that and put together the new theory, what we call quantum mechanics today.

And it's quite remarkable because in a few months, they come out with two or three papers that basically have all the theories that we study today at school. And to their great surprise, they receive a letter from England, where a young unknown kid, also in his early 20s, whose name is Paul Dirac, who had heard Heisenberg talking and who had received the first draft advisory paper, independently comes out with the same theory based on the Heisenberg first input. So somehow, quantum mechanics is born twice in the UK and in Germany, in the same form.

It's a beautiful, beautiful formulation theory, the very first formulation theory, not the one which is usually taught first in the universities, the one which is taught first was born later in Switzerland, by Schrodinger, and is based on a wave equation. But the original formulation by Heisenberg and Born and Jordan and Dirac, it has no waves. It just gives the predictions of what we're going to observe on the basis of what we have observed. First, people are immediate surprised. Einstein writes, in a letter to Born, who was a friend of him, that everybody in fundamental science, who was interested in fundamental things, is following this calculation with enormous interest.

And I think it's amazing. He calls this witchcraft calculations. It still looks like witchcraft calculations, because this is a strange way of computing things, which it's a completely different logic from the previous one, right? Once again, instead of describing how things move, it describes sort of a black box. If you see this, and then you compute, you compute … bingo, you got to see that it works. And it described nature's very, very well. It was called Knabenphysik physics in German at the time, because they're all kids, the “physics of the boys”, but let's not forget that not many years later, it's the physics that is the use to construct the atomic bomb.

So the power of this new physics is without question. Thanks god, it’s not just bombs that have been made with it. Bad things, and good things have come out from this immense power that has been this discovery of quantum theory.

NSS:

And can I ask you, Carlo, because you're interested in physics and also philosophy, and you describe in the book how you had that adolescent curiosity and sense of wonder around this subject … what led you to it? And do you think there's something about open minds and fresh eyes and philosophical outlook that brings people here?

CR:

I think that science is fascinating. I find science fascinating. Not because it gives me explanations about how this little thing works or this other little things works, but because it's the path of discovery of humankind, which is very awesome. And figuring out that the world is not the way we thought it was. So science grows by unlearning what we previously learned more than by learning new things. And this is beautiful. I know some people were attracted by science because it's solid and gives certainty, I am attracted by science for the opposite reason, because it questions all our certainties. And quantum mechanics is a typical, it's a prototypical example of that, but there are many, many other examples: when we discover that the earth is flat, or is not the centre of the universe, or so on, solid things are not so solid as they look, if we go into details they are sort of empty, with the moving atoms, and so on and so forth. The science constantly changes the picture of the world, in front of us, and it’s a constant path of rethinking reality, finding new conceptual structures for thinking reality.

This is what has fascinated me as a young man, when I said, “Wow, this is science is great.” And this is still what I like in times of quantum gravity, which is trying to understand the quantum mechanics of space-time itself, something we don't know. So there's nothing as humbling as doing fundamental science. There's an image you know of the scientist as somebody who pretends to know, he knows everything. The reality is the opposite. I mean, the more you do science, the more you realise that you're ignorant, because we don't know how things are, and stupid, because you spend your time thinking, “boy, if I was smarter, perhaps I could understand that, and why I am confused? I don't understand that.” So it's a very humbling experience. Fundamental science, I believe, is constantly comparing ourselves with the weakness and the incompleteness of our understanding of the world.

In these moments, we human realise what we thought [we knew] is only an approximation. Oh, it was good. I mean, Newtonian physics is very good. We still use it to build aeroplanes and houses. But it's not that we have understood the world. We have understood a little thing. And this step by step, going into the unknown, it's what for me is the fascination of science.

Alice Bloch:

Hi, there. I'm Alice Bloch, producer of With Reason, and we're coming to you from the Rationalist Association and New Humanist magazine, where deputy editor Niki Seth-Smith is talking to the physicist Carlo Rovelli, about the world of quantum physics. It’s a conversation about reality research, and in, a moment, relational theory.

If you like what you're hearing, please do press pause and click subscribe in the app that you're using to listen to this right now. Or leave us a review or a whole five stars. It costs nothing, and it helps us to make more episodes that are free for you to download and enjoy whenever you choose. Back now to Niki's conversation with Carlo.

NSS:

So Carlo, you're a proponent of the relational theory of quantum mechanics. Essentially, objects only exist in terms of their interactions with each other in this theory, is that right?

CR:

That's exactly right. The relational perspective, the relational view of quantum theory, is one of the attempts to make sense of string theory. It's part of a group of similar attempts. I've been working on it since the ‘90s. There are many other people who have worked on it. And the problem is, what does it mean that we have a fundamental theory of the world that doesn't tell us what happens, it only tell us what we see? And the central idea of the relational interpretation is that quantum mechanics has nothing to do with us, specifically. The observer who observes is not special in any sense. It's just one part of nature.

So the way to think about that is not that the theory is about that we describe nature in terms of, you know, where is a stone when we look at it. The way of taking us out from that is to realise that the best way of describing nature is to think about how the stone interacts with anything else. So we are just one piece of nature, like any other piece of nature. Of course we're complicated, with a brain, we take notes, some of us are scientists. But what is going on fundamentally is not because we have a brain or we take notes or anything like that. What goes on fundamentally, is that nature can be broken into systems: A stone, men, woman, villages, sand, photon electrons …. and these interact with one another. And we should not describe reality in terms of how each one of the systems is at any moment, but in terms of how each one of the system affects the others.

So, a stone that hits another stone manifests itself in this hitting, okay? A stone that we look at, it manifests itself, you know, by sending a photon to us that we receive. So, instead of thinking of reality as a set of object with properties, we should think of reality as a set of things interacting with one another that have properties when they interact, the properties or the ways they affect one another. And therefore, a property is always relational. This is the name: relational quantum theory, relational interpretation quantum mechanics. Namely, the position of a stone is always relative to something else, it's a way we call the fact that the stone can affect something else. When it’s not interacting with anything, not hitting anything, it does not make sense to ask, what is the position of the stone? Because in a sense, as Schrodinger said: Look, we should not think of the electron as always there, we should think of it as a sequence of snaps of interactions with other things. And that I think, is the right intuition. So no subjectivity, nothing to do with humans, with observation, with consciousness, with minds, or anything like that. Pure physics, but not physics of object with properties, physics of interactions between systems.

NSS:

We were talking before about how science undoes - or we have to unlearn much of what we would find intuitive. But that's a deeply unsettling proposition, because it seems to indicate that truth is relative.

CR:

Well, truth. Truth is, it's a big word that can mean all sorts of things. And it can be used in different ways. To some extent, we know that a lot of tools are relative, right? Fine. I mean, there are things which are true in one sense and not true in another sense. There are a lot of aspects of nature that are true in one sense or not true in another sense, and we have accepted them. Even if it is not easy. Let me make an example. What does it mean “I don't move?” Okay, I'm not moving right now. I stay completely still. But however, we also have learned that not to move, it only makes sense relative to something else, right? Because the earth itself is moving. So when I say “I'm not moving,” I'm actually moving with respect to the Sun. And if we think about that, I mean … when a mother tells her little kid on a train “Don't move”, she does not mean that the kid should jump out of the train. So that's it. To be not moving is a relative truth, it’s not an absolute truth. Does this question our sense of possibility of knowing the world? No, it doesn't. It just articulates it, it makes more clear that things are more subtle sometimes. So if I see a pen here, I know that the pen is here. But if physics tells me “look, the fact that the pen is here is relatively to you as a physical system, and it might be with respect to something else that the pen is not exactly here,” well, that's a more subtle way of understanding reality. I don't think we should be afraid of that.

And in particular, if I might talk a little bit more in general, we should not be afraid that they’re not truths, with capital T, or certainties, with capital C. The entire history of science is a sequence of demolishing tools with capital Ts, and certainties with capital Cs. We can still live perfectly well, with our very partial understanding of the world, with partial tools, with partial certainties, and complete certainties. And life is very good.

NSS:

And you're quite a vocal proponent of relational theory, but can you just give us a really brief map of the different theories out there?

CR:

There are a number of theories, but they're often variants of the same few ideas. And I would say that maybe the interpretations that are most discussed, those that are central, are three or four, no more than that. So the relational interpretation I just mentioned, is the idea that properties of objects are relative to something else. And it's rooted in the original Heisenberg idea that an electron doesn't have an orbit by itself, it has only a way of affecting the world outside. A completely opposite perspective is called the Many Worlds Interpretation. And it goes the opposite direction. It says that everything is a wave, okay, so the electron is never in a position, the stone is never in a position. It's always in a wave of different positions – you know, technically, we say, in physics, a quantum superposition of different positions – it’s here and also there. And that's, in my opinion, even more radical than relational quantum mechanics. But it's a very realist interpretation. So it doesn't have these relative tools that you hinted a little bit ago, because you have to imagine this huge wave.

Now, what is it? What's the cost of that? The cost of that is that one has to make sense of why we see the electron in one position, or we see the stone in one position, and not in many positions. And the story in this interpretation is that a stone can be in many places at the same time. But when I look at the stone, I myself spread, in many superpositions of myself, in many different versions of myself, each one of which sees the stone in a different position. So I, myself, am a wave. And I think I'm only in one position, and I see the stone in one position, because I'm one component of this wave. So if one want to go that way, one has to sort of imagine that there are many worlds, not just this one in which things have these positions, but many others in which things have always held a position. And I myself have all sorts of positions.

A third alternative is called the hidden variables. And that’s a sort of mixture of the two. I mean, hidden variables people think that one can make sense of one mechanics by assuming that there is this wave, but also out of the many positions of things, one is privileged. So there's a wave, but also the particle which is in a position, so they multiply entities. And for technical reasons, this actually works and allows us to make sense of what happens and have a more sort of traditional picture of the world. I mean, the stone is moving, but also there is a wave that tell us where to go. So it's more reassuring philosophically, but it has a big cost in terms of adding things we don't see.

Then there is an attitude, and I would say this is the fourth one, which is not really an interpretation, but it's an attitude, which is common among many physicists, which is to say, “Well, whatever happens, whatever you do at the fundamental level, after all, the big things like you and me and the stone and the mountain and the car, [with these things] the quantum phenomena are negligible. So why don't we forget that they are quantum and we use them as references and we use quantum mechanics only for the things which really manifest quantum phenomena, like small electrons? And then we say, okay, so when they interact with big macroscopic things, that’s when the theory is not very convincing, because you know, it's basing individual theory on something which a theory says is wrong. Because I am quantum, you are quantum, everything's quantum. But practically, it works perfectly. Because I mean, forget the problems, don't think, and just use the theory when it's needed. So many physicists are less interested in posing basic questions in a perfectly legitimate way. They just use quantum mechanics without asking these questions.

NSS:

It's quite extraordinary that the basic principles of this fundamental basis of reality were discovered a century ago, and we're still kind of struggling to grasp it. You make a plea at the end of your book for people to try to fully absorb this vision of reality. What do you think would change if we were to see more clearly?

CR:

First of all, quantum mechanics, as a huge scientific revolution, does change the way we think about reality. There is another major revolution in physics that everybody knows, which is the Copernican revolution, which started with Copernicus, and sort of lasted, the change took a century or more, because it was only in the time of Galileo and of Newton that it became clear that Copernicus was right. Namely, that the Earth is not the centre of the universe and that not everything goes around the Earth. But it's better to think that the Earth is just one planet that goes around the Sun. So the Earth is moving. And on the one hand, that Copernican revolution, took long to be absorbed by the culture, and people were very confused. At the beginning, it was very hard to accept the idea that we're moving very fast with respect to the Sun. And in a sense, people could say, “well, who cares?” I mean, you wake up and have your breakfast and do your things. Whether the Earth is moving or not, it doesn't, doesn't concern us. But still, the Copernican revolution changed our view of ourselves in a very profound way. I mean, the fact that we're not the centre of the Universe, but we live in a little planet, a little spinning rock, one of the many, many stars in one of the many, many galaxies, changed our view of ourselves.

I think it's a little bit the same with quantum mechanics. It asks us to rethink what it means to be real, what it means to be an object, it pushes us toward thinking in terms of relations rather than in terms of objects. We can still wake up in the morning, have breakfast, and think that, “you know, my croissant, my French croissant, is a very good object. I eat it, period. It has its own properties, whatever quantum mechanics says.” But if we digest it, and if the culture absorbs it in the way the Copernican revolution was absorbed, I think it's going to change. But it's not going to change in a way which is after all, so dramatic, because there are many other aspects of culture which tell us that thinking in terms of relations and interactions works better than thinking in terms of objects. It's a lesson that we have learned from anthropology, from psychology, from linguistics, from a lot of other disciplines, even biology. You don't understand a living being as it is by itself, you understand it through its interaction with the rest. And the fact that even physics, which was supposed to give the ground for everything else, even physics is so relational, pushes us towards and gives more centrality to relations, to interactions, rather than to objects. And I think this is a lesson that could be useful for us at every level, including our psychology, and including politics.

NSS:

That's a beautiful lesson. Carlo Rovelli, thank you so much for joining us.

CR:

Thank you very much.

NSS:

Carlo Rovelli, theoretical physicist and author of, most recently, the book Helgoland. And we didn't have a chance to dig into our archive there, as we often do. But if you want to read more on physics from New Humanist, do head to our archive online where you can find an interview with the theoretical physicist Frank Wilczek, from 2015, that looks into his ideas on the relationship between physics and beauty.

So I'm back now with Samira, who's been listening along to my chat with Carlo. Samira, I learned a lot from that. I don't know about you.

SS:

Yeah, much the same really, it was such a wide ranging conversation and so lively in a way that I think we might not assume a conversation about quantum physics is going to be. So that was brilliant. And something that jumped out at me is something we actually touched on at the very start of this episode, this question of narrative. I loved the way that Carlo brings to life the theories with the stories of the people who came up with the theories and developed them and so on. I particularly like that because I guess we can easily think, particularly as non-scientists, of these abstract theories as being just that – sort of abstract and conceptual, and you forget that they come from living breathing people, and they have all these sort of human inputs to them.

NSS:

I think it was captured in the interview, but also in his book, he just writes incredibly lyrically, especially about this island Helgoland. He uses those metaphors of the sea, and waves, the waves crashing on the rocks, actually to kind of illuminate and help describe wave theory – and also just this feeling of being kind of fluid and all at sea, which is the experience of trying to understand this relational theory.

SS:

Yeah, it's all quite mind-boggling to get your head around and it makes me think about that part of your discussion where you were talking about truth and certainty, and that really stood out to me, I think, because we've just had this last 18 months, where “follow the science” has been a sort of government mantra, as if it's an end to the conversation or argument in itself, this idea that science is a sort of full stop because it's immutable and is definite and it can't be argued with. And that's the opposite of what Carlo is saying from his study of this. I like the way that he talked about science being humbling, or science being accepting the unknown, which I think is often the opposite of how it's represented. But there's something very, very resonant in that, sort of thinking of it in this different way, that science is about what we don't know as much as what we do know.

NSS:

Yeah, I mean, opening up as many questions as there are answers, but still incredibly fascinating as a discussion. And that's it for today. But remember, you can find transcripts and reading list of all episodes of With Reason on the new humanist website.

SS:

And if you go there to newhumanist.org.uk/subscribe and enter the offer code WithReason, you can get a year's subscription to the magazine for just £13.50. That's half price, and it means you'll get a beautiful quarterly magazine and access to our full digital archive which goes back over 100 years.

NSS:

This podcast is presented by me, Niki Seth-Smith, with Samira Shackle. The executive producer was Alice Bloch and the sound engineer was Dave Crackles. See you back here soon. Goodbye.

Further reading:

'Helgoland' (2021), Carlo Rovelli

'There Are Places in the World Where Rules Are Less Important Than Kindness' (2020), Carlo Rovelli

'The Order of Time', (2018), Carlo Rovelli

'Reality Is Not What It Seems: The Journey to Quantum Gravity' (2016) Carlo Rovelli

'Seven Brief Lessons on Physics' (2015), Carlo Rovelli

'‘‘The beauty in physics is the kind of beauty that people have embodied in art’’ , a Q&A with Frank Wilczek (2015) by Daniel Trilling, New Humanist magazine.