Episode 5The Origins of Life: Do we need a new theory for how life began?

Episode Transcript:

JB: Justin Brierley

JE: Jeremy England

PD: Paul Davies

JB: Hello and welcome to the Big Conversation from Unbelievable brought to you in partnership with the John Templeton Foundation. I’m Justin Brierley and the Big Conversation is all about exploring the biggest questions of science, faith, and philosophy with leading thinkers across the religious and non-religious spectrum, and today we’re exploring the origins of life and asking do we need a new theory for how life began?

This season is being recorded remotely for obvious reasons, but the silver lining is that it allows us to bring fascinating voices together from all over the world. And joining me today are Paul Davies and Jeremy England. Paul Davies is professor of physics at Arizona State University, as well as being the director of Beyond: The Centre for Fundamental Concepts in Science. He spent a lifetime probing the big questions of origins and his most recent book, ‘The Demon in the Machine’ explores the way that hidden webs of information may be solving the mystery of life.

Jeremy England is a physicist who’s currently senior director in artificial intelligence at GlaxoSmithKline, and principal research scientist at Georgia Tech. And Jeremy is at the forefront of researching how the science of thermodynamics may provide an answer to life’s origins. Fascinatingly, he’s also an ordained rabbi and brings both the Torah and his science together in his recent book, ‘Every Life is on Fire’.

Well, the first microbial forms of life arose on earth perhaps 3.5 billion years ago, but how? And why would inanimate matter, go to the trouble of becoming a living, self-replicating organism with the potential to ultimately produce conscious intelligent humans able to explore our own origins? Well, Paul and Jeremy are both working at the cutting edge of this research but are also open to those wider questions of whether the deep principles in the universe that seem geared towards life may reflect an ultimate purpose or even creative intelligence that transcends even the science they do.

So, Jeremy and Paul, welcome along to the show. Great to have you both with me.

PD: Great to be here.

JE: Great to be here.

JB: Great to have you both. Jeremy let’s start with you, you’ve got the rare honour, I think of being used as the basis for a character in a Dan Brown novel. Tell us about that, and whether it was an accurate picture of you and your science.

JE: So, the context for that, I guess is that some work that I had been doing in my lab, while I was still in the physics faculty at MIT, had gotten some popular attention over the years in kind of the broader press. And I guess Mr. Brown picked up on that and decided that it was an interesting thing to work into a book that he was writing. He told me that he had done this, I think, a month before the book came out, or something roughly, on that timescale, asked if I wanted to get lunch out of the blue, and I wasn’t really sure why and told me it was happening. So, I didn’t really have any role to play beforehand in any kind of discussion about how I’d be portrayed. And I discovered, when reading the book, how, I guess, ideas that I put out in the world had influenced his thinking about things a bit. I wouldn’t say that it ultimately came out very accurately, although I think maybe the standards for science fiction or whatever you would call it, have to be forgiving in that regard. But I would rather make my own account of what I think both on topics of the science, and also maybe broader topics, like some we’ll end up discussing today, rather than I think stick with the one that he put in there.

JB: Yes, I mean, there was some fairly non-religious sort of conclusions in a sense to that novel and indeed, to the character, and obviously, that doesn’t actually reflect your own personal beliefs on that level. But in a way that book was tied into some of the issues we’re going to be discussing today, the origins of life and so on. And how much has in your own life, the science you do, the physics you do, has ever been in conflict with, obviously, the faith that you hold, which I believe was really discovered afresh while at university for you?

JE: Yeah, I think that perhaps in part because of the strange trajectory I ended up taking personally with respect to this, it’s mixed together and in a different way than sometimes what we think of as being more common. So, I grew up in a home where I had a sense of Jewish identity, but not a strong sense of religious faith connected with that. And I really only took an interest in those kinds of questions when I started reading, having a bit more time to explore new horizons, actually, when I was studying as a Rhodes Scholar in Oxford after my undergraduate years. And that was the first point where I started to read the Hebrew Bible and really engage with what was in it and ask questions about it. And I was already quite grown up as a scientist by that point and had really learned a lot of things and was quite convinced of the value of scientific reasoning and figuring out things that are true and predictable and understandable about the world. And so, I think I felt very sure, as I started getting into the Jewish tradition and the Torah and the Bible that I didn’t want to let go of that. But at the same time, I was also interested to see what else I could learn from that different way of talking about the world. And so, I think I haven’t ever encountered a conflict, because I’ve kind of insisted from the beginning that there can be a way to find a combination of these perspectives that really has an enriched understanding of everything.

JB: We’ll come to that more obviously, later on in the show. It’s such a pleasure to have you with me, and I’m really looking forward to the engagement today with my other guest, Paul Davis. Paul, I don’t think you’ve so far featured in a Dan Brown novel, would that be fair to say?

PD: No, I featured in a couple of novels, but not a Dan Brown one. The first one was called ‘Timescape’, by Gregory Benford, a science fiction writer. And it was many, many years ago and the nature of time is a long-standing research interest of mine. And he worked me into that. And the sad thing is that the time we met, which was in the mid 70s, I was working at King’s College in London, in the book, which takes place in 1999. I’m still there, beavering away at the same old problems. By then I’d actually moved on. But of course, it was a something of a thrill to discover myself as a character in a novel.

JB: Yes, I’m sure. That’s one way to sort of go down in history, isn’t it? To be immortalised in fiction. I mean, a lot of what we’re talking about today has, to some extent featured in science fiction in various ways, people trying to think about where we’ve come from, and that kind of thing. I mean, Paul, what led you to start engaging with the origins of life, because you’re a physicist by background. And normally people say, we stick to our areas, and most people think origins of life, well, that’s biology, right?

JE: Well, like many people, I was drawn to the subject by reading Schrodinger’s little book, ‘What is Life?’ as a student, and that coincided with the work that Brandon Carter, who is an astrophysicist and cosmologist, had done on the so called ‘fine-tuning problem’ – the fact that if the laws of physics were a little bit different then there could be no life in the universe. And so, these things both intrigued me, but the origin issue itself was propelled to the forefront of my consciousness by Martin Rees, now, Lord Rees, former president of the Royal Society. In 1983, he held a conference in Cambridge called ‘From Matter to Life’, and I attended that conference. There were all sorts of luminaries from across the physics, biology, mathematics divide. And I began to think really, rather deeply about it. I must say, I’d also been influenced as we were talking about science fiction by Fred Hoyle’s novels. So, Fred Hoyle was a great British cosmologist, a somewhat prickly character with unusual views, but also very brilliant in many ways. And he wrote a book called ‘The Black Cloud’, which features a cloud of gas that is, in effect, a living, thinking agent. And I remember at the time being sort of mystified, how can a gas be an agent, because clouds of gas just obey the laws of physics, they just do what clouds of gas have to do. And then I thought, hold on a minute, we’re all made of molecules and molecules have got to do what molecules do, so what’s the difference really? And all of these began to come more and more in my consciousness, and when I moved to Australia in 1990, I then started getting interested because I had been in the University of Newcastle-upon-Tyne in the physics department, that had lots of geophysicists, and people interested in meteorites and comets and impacts and things like that. I became interested in the idea of comet an asteroid impact on earth propelling material from Earth to Mars, or in the other direction and the possibility of life being transported in that manner between near neighbour planets, and I began lecturing and writing about that in the early 90s. And everybody laughed and thought it was an absurd idea. And all that change when Bill Clinton stood on the White House lawn in August of 1996 and announced that NASA had a meteorite from Mars with evidence of possible fossil life in it and so suddenly, that whole subject took off and that was really my entree into what we now call astrobiology.

JB: Yes, indeed. So, you’ve been sort of cross disciplinary in that way for quite a while. What have people made of your entry into the sort of physics entering into the world of biology, by looking at the whole origins question yourself, Jeremy?

JE: I guess for me, I started my academic career, not being able to decide whether I was more interested in biology or in physics. So, I majored in biochemistry as an undergraduate, but sort of use that as a way of cheating and only taking the physics classes that I wanted to, but still largely studying physics. And then from there, I was always trying to kind of do both things, because I didn’t want to give up on the one hand on the sort of beautiful simplicity of physical theories, and how you can explain lots of things with a few assumptions. And on the other hand, the kind of functional complexity and particularities of living things that you can’t get unless you get into how living things work. I wanted to work in both of those things, and I think through my whole career, I was trying to find theoretical problems, where physics had something to say that was important to understanding something in a biological system. And initially, that took more of the form of a very common and important and interesting form of theoretical biophysics, which is taking a piece of a living thing and saying, well, how does this work according to our understanding of the laws of physics? And how does that allow it to accomplish its function? But then there’s a different kind of question, which pertains more to what Paul was referring to, and that’s more of the question of if you start with matter, that doesn’t impress you as having what you think of as the distinctive properties of life, and why would it get that way? And is that even a question you can pose within the framework of physics? And if so, what does physics have to say about it? And then I think that I got more drawn in that direction as time went on. So that, by the time I was starting my lab at the beginning of my professorial career, when I was at MIT, I sort of said, okay, let’s try to see what we can do to make a dent in that. And for a while, I think I didn’t really have an idea of how to go about it. But over time, it started to seem like there were these relatively new ideas and non-equilibrium thermodynamics that that could be relevant. And so, it all kind of germinated from there.

JB: Well, we are going to be using some technical jargon, no doubt, in the course of today’s show. You’ve already said the word ‘non-equilibrium thermodynamics’, and many people will be wondering what that is. We’ll come to all that including other phrases like ‘dissipative adaptation’ if I’m even saying it correctly. But we’re going to try and keep this at a level where frankly, I can join in as a lay person. But at the same time, obviously trying to elucidate these concepts, and it is just one of the most fascinating areas, why is their life? Why was there this propensity for inorganic stuff to become living, breathing organisms and eventually us, of course? We’ll come to Schrodinger in a moment’s time, because you both really in both of your books, that’s a starting point for you both. But let’s talk about life, first of all, and whether we can even define that. What are some of the key aspects of what you would, Paul, see as defining something as having life, as being a living thing?

PD: Yes, of course, this could be a very long conversation. It’s notoriously hard to define life and part of the reason for that is we only have one sample of it. If we can find just one other sample of life, we will be able to separate the essential features from the incidental features. Now, a few things, of course, in all the textbooks like reproduction, for example, and metabolism and so on, but I like to boil it down at the end of the day, to what I prefer to call hardware and software. That life is complex chemistry. So, we have a complex physical system, far from equilibrium, we can’t avoid getting into that. And that does sort of surprising things has an advanced predictability to it. And all that is true of many systems we wouldn’t normally think of as being living like hurricanes, for example. But the key feature of life is that it’s not just hardware, it’s software as well. It is full of information processing, storing, and replicating systems. So, it’s information managed, if you like, complexity, and it’s putting that hardware and software together that, for me is the real challenge of explaining the origin of life. You can explain how complex chemistry comes to exist; how non-equilibrium systems come to exist. But how do those systems develop information management overview and so from that emerges agency, understanding and all the other things I’m sure we’re going to talk about. So, I think for me, the definition of life is, just to boil it down to a pithy phrase, it’s sort of chemistry plus information.

JB: That’s interesting. Would you broadly agree with that yourself, Jeremy?

JE: Certainly, if we think about, as Paul mentions, the examples of life that we know, they are all really excellent, and in a sense, extreme examples of really beautiful and marvellous information processing, and it’s hard to remove that from our idea of what they’re doing. And so, I wouldn’t disagree with that characterisation. I think in the approach that I’ve tried to take in thinking about this problem, part of what I’ve tried to advocate for, is trying to divide and conquer to some degree. So, if we think about the things that living things do, can we define different behaviours that we would call distinctive of life, but not unique to life, and where each of them may be, there’s kind of a spectrum in terms of how extremely good at them that you might be. So, there are things like copying yourself or predicting your environment, or perhaps harvesting energy from a difficult to access source. There are things that living things do, where if we picked each one of those things, we could list many examples of stuff that matter does that you might call self-copying, or you might call in the limited way predicting its environment to some degree, but where you wouldn’t want to call it alive. And clearly the best examples of what we would call life are these extreme agglomerations of many of these different behaviours. But I think it’s helpful, not so much in let’s say, describing life as we know it, which are all these very highly optimised and extreme examples, but in defining this grey spectrum back to the point where you’d say something is totally lifeless, to start thinking about how you start dialling down with various separate behaviours. And what’s interesting is, you could start to say, maybe I have something that’s extremely good at predicting, but it’s not a self-copier, or maybe something that’s extremely good at self-copying, but it’s not necessarily doing something that looks like very successful and challenging energy harvesting yet, etc, etc. As a result, with regard to your question, being good at information processing, I think ends up being a pressure that the system comes under, when it wants to be extremely good at many of these behaviours and so they kind of get wrapped together at the endpoint in what we call definitely alive, as having that ability, quite strikingly. But I think maybe it’s still helpful when building physical models also to kind of have the playbook that allows you to fill in the grey spectrum of things that are starting to self-copy, are starting to sense and predict, and that also involves information processing, but where you don’t have to be as good as something that has a DNA that it copies and uses to transmit information in a way that looks much more like a computational process or a code.

JB: We’ll come to talk about this a bit more in a moment’s time, but let’s talk a little bit about what life looks like at that small level, which you do so well, in your book, The Demon in the Machine. I mean, Francis Crick, obviously who first proposed the DNA molecule described the origin of life as almost a miracle and when you do look at the complexity of what’s happening inside living cells, the apparatus, the processes involved, even in the very simplest of biochemical machines. You describe in the book a kinesin walker, a sort of raptured engine, and other things. Obviously, the way DNA and RNA replicate and the error correction going on. These are incredibly complex processes, aren’t they? I mean, do you want to just describe some of what’s going on in the cell that many people obviously are completely oblivious to, how complex it all is?

PD: Yes, because while you’re quite right, it is staggeringly breathtakingly complex, so, even the simplest living thing, as simple as bacteria, about the simplest autonomous living thing is just beyond any capability of human technology to match. People often talk about, oh, we’re making life in the lab, but they’re not talking about this. They are talking about re-engineering life. And so, what we have is this enormous complexity and one way of thinking about this, if you want to take an engineering approach is that the living cell is like a bag of nanomachines, incredibly efficient in most cases, coupled together in a way, and I can’t avoid it, that is under some sort of information management. So, there’s an entire network of command and control. So, this isn’t just sort of arbitrary chemistry and blundering around. Although there’s a fair amount of randomness, what we call stochasticity driving this, but nevertheless, there’s a directionality to it that emerges. But at the level of complexity, it’s been mentioned the kinesin walker. So, there are many little nano devices or nano machines that operate with extraordinary thermodynamic efficiency, very close to what is perfection. And this particular molecule we mentioned, it literally walks along fibres in cells delivering cargo. And there are many examples of this, and it all has to be choreographed with very great precision to work properly. And so, I suppose, if you’re an engineer or a physicist, and you drill down into this like an entire city of complex processes going on all interlinked and coordinated with a coherent outcome, it just looks really extraordinary. And if we could just come back to the origin of life question, and Jeremy quite correctly said that there’s a whole bunch of properties and the sort of information management is like, in a way, the refinements and honing of those properties, I think the real issue that we have to deal with, in the case of the origin of life is, is it a long pathway of increasing complexification, where this property begins to be manifested, then that one, then that one and it all sort of comes together at the end? Or was it more like a phase transition in physics where everything would spring into existence all in one go and suddenly there will be like, gas bursting into flame. We don’t even know whether it was a gradual pathway or an abrupt transition. And when we talk about the origin of life, I think most people have the impression that there’s a mishmash of chemicals, and then suddenly, something amazing happens and hey, presto, it’s alive.

JB: I think, in all honesty, a lot of people even confuse it, people who aren’t familiar with the area that, oh, I presume Darwinian evolution sort of accounts for the origin of life. But of course, you don’t get an evolutionary process until you’ve got a self-replicating molecule, something that evolution can then go to work on.

PD: That’s a really important point because Darwin himself would not be drawn on the origin of life. He said, one might as well speculate about the origin of matter. So, it’s a wonderful quote, particularly as physicists have now explained the origin of matter. So, you know, can we now explain the origin of life? He did speculate about a scenario. But of course, you’re absolutely right, he gave us a theory of evolution about how life has evolved over billions of years from simple microbes to the complexity of the biosphere we see today, but he didn’t want to tangle with how you go from non-life to life. And for me, that’s a much bigger step. Because when people say, well explain today’s biosphere. It’s amazing. But the transition from the earliest microbes to what we see today, of course, it’s an enormous amount of complexification. But it’s got nothing on that first step of going from a mishmash of chemicals to the first living thing, because almost all the complexity in the biosphere is in the individual organisms, not in the subsequent ecology and everything else. Marvellous though that is.

JB: And this, Jeremy is why it is such a hard problem, isn’t it? Because it feels like your most you need the stuff in place to start with, but it just doesn’t seem at all, likely, parsimonious that it all just happens to come together in some fluke accident. The odds seem massively stacked against that idea that it was just some jumble of chemicals. Where do you think, before we go into your own research and we want to dig into this, where do you think that generally efforts have been concentrated up to now in origins of life research and are they in any way fruitful? I mean, you’ve had the called Yuri Miller experiments back in the 50s, or whatever. And I hear lots of people say, well, they really haven’t got anywhere beyond that, you know, managing to produce a few basic building blocks, a few simple amino acids, you know, when they mixed the chemicals together and put some electricity through it. No one’s really progressed a great deal if we’re just looking at the chemical constituents from that side of the origins of life research.

JE: Well, I think that there are a lot of different pieces of elephant that you can grab on to and so if you take different things that are part of what life is, you can focus on one of them and then I think there has been progress to some along many different directions in saying, do we understand a little bit more maybe how you start to get membrane enclosed objects emerging in a certain setting? Or do we understand a little bit more how maybe you might start developing polymers that contain in the sequence of building blocks that are constructed out of something that could be used for the transmission of information. There’s been a lot of different efforts along those lines, where I would never want to say, no one’s made any progress and thinking in those terms. But I think what’s quite challenging is that life is such a collection of different things that work so well together, not just different components, but different. separate behaviours, or separately striking successes in the overall accomplishment of the thing as a whole. Whether it’s self-copying, whether it’s modularity, you know, meaning you can break it into different separate functional parts. Lots of different things, you could list that it always seems like tackling one of those things maybe feels a little bit incremental, like a membrane enclosed droplet of oil is not the same thing as a cell and a polymer that maybe can kind of sidle up a long time alongside another polymer and stick to it in a way that seems to be sort of a template, like DNA is a template, is not the same thing as a cell that makes proteins according to rule that are kind of computational, specified by the DNA. So, it always feels like there’s a very big standing leap from where you are to where you need to get. But I do think that there was a comment you made earlier, Justin, which I think it is worth pulling on the thread a little bit, the question of, can you get something evolutionary that happens before you have self-copying things that allow for a Darwinian mechanism. And I do think that is something that we should look at carefully, because the naive scenario of, everything was just kind of a random mess and then once you get the Darwinian mechanism going, you can really start seeing adaptation and optimisation to happen. We have to chip away at that and ask how naive or how messy or how random was the rough cut, was the starting toolbox before you got to put something together into a self replicator that can really start experiencing Darwinian pressures. And I think that’s where it gets, I would argue, interesting, because you can start making physical arguments for why there’s certain kinds of optimisation or adaptation, you should be able to see, even in a pre-Darwinian setting, and it maybe doesn’t get you life, but it could get you a relatively rich toolbox of things that already looked like they’ve evolved or been adapted or optimised to accomplish certain tasks, just lying around, so to speak, for life to be born from.

JB: Well, we’ll come back to that and in the next section of today’s show, I want to start digging into both of your specific theories as laid out in your books. And that’s where we’ll start with Schrodinger and his essential point about the fact that life seems to contravene the second law of thermodynamics. We’ll explain what that is, and why life seems to push against it. And some of the theories you’ve both come up with of just how life managed to do that. We’re talking about the origins of life today on the Big Conversation from Unbelievable, my guests are Paul Davies and Jeremy England.

Welcome back to today’s edition of the show. We’re asking, do we need a new theory for how life began? Today my guests are Paul Davies and Jeremy England. They’re both at the forefront of looking at origins of life research, and both have got great books out on that subject, The Demon in the Machine from Paul, and Every Life is On Fire from Jeremy England. And we will get to talk about some of the theological ramifications of this as well as the programme goes on. Right now, though, folks, I want to dig into your actual theories. Now, I mentioned already Schrodinger, very famous physicists, obviously, when it comes to quantum physics and his famous cat analogy has gone far and wide and has spawned a whole number of thought experiments involving doing not very nice things to animals. But one thing that you both picked up on is that Schrodinger wrote a little sort of book or essay called What is Life? Again, a physicist trying to look at a biological subject. But one of the things that he struck on was this idea that life seems to contravene the second law of thermodynamics. Now, do you want to explain what that is, first of all, Paul, and why life seems to push against it?

PD: Yes, well, first of all, I should say that the second law of thermodynamics was developed in the 19th century, largely to deal with practical problems of heat engines and efficiency of things like that, but it was soon found to have a very general applicability. And so, in one sense, it’s the most fundamental law of physics that we know. And it has many different forms. But one way of thinking about it is that there’s a natural tendency in all living systems to become disordered, or more chaotic. And any in the audience who have teenage children will, I think know exactly what I mean by this.

JB: In their bedrooms. [laughs]

PD: In their bedrooms. It’s much easier to mess things up than to clear things up. And that’s a general principle of nature. And if you want a rather more concrete example, imagine taking a pack of cards newly purchased, and you open them, I’ve never actually checked this, but I understand that they come in suit and numerical order, and then you shuffle them, then, of course, they’re going to become disordered after that. If you gave somebody a disordered pack of cards, and they shuffled them for a few moments and gave them back to you and they were in an exact ordered state you, you’d know, you’d been tricked by a magician. And so, in nature, there is that general and unsurprising tendency for order to give way to disorder. And so that’s the one statement, the second law of thermodynamics. It’s very, very well established, well, Schrodinger pointed out, and I think many people have recognised this that life seems to buck that trend, it seems to go not from order to disorder, but from order to more order. Both in individual organisms, the way they take in disordered stuff from their environment and do things with it, but also from one generation to the next. If we look at how life has evolved, the degree of complexity we were talking about earlier, one way of thinking about that is a greater degree of order today than in the past. So, it does seem to buck the trend. When you look at the letter of the law, there’s no real contradiction and I think this is really important for people to understand that it’s not that life is violating the second law of thermodynamics, it transcends its simple picture. Because what I said earlier, of a natural tendency from going to order to disorder. That’s in a closed system. So, when I was talking about in the 19th century, people had in mind a box of gas, for example, which was closed off from its environment. And if you start the gas off in an ordered state with, say, all the fast molecules at one end and the slow molecules at the other, they’d soon intermingle. And it reaches some sort of equilibrium. And life is not like that. Life is an open system, there’s a throughput of energy, and export of chaos, or entropy is the quantity we talk about it. And so, it maintains its internal orderly state by exporting the trail, if you like, to the environment, and that’s the absolute key. You see it also in the history of evolution, life on Earth, that for every more successful, more complex, mutant variant that you get, there’s a trail of destruction for all of the others that were sacrificed in order to achieve that. And so, there’s a trail of disorder in biology, both around individual organisms and in the deep evolutionary history. And so, when you do the numbers, the books balance okay, that the second law of thermodynamics still survives. But and I just want to make this important point, because we may come back to this later, just because life doesn’t violate the second law of thermodynamics absolutely does not mean that the second law of thermodynamics explains life. A lot of people have fallen for that. Some scientists have said, oh, there isn’t the problem when you look at it carefully. Life is explained by the second law of thermodynamics. It doesn’t contradict it. But the second law doesn’t explain it. We need much more than that.

JB: Yes, well, obviously, Jeremy, this is where we’ll bring you in, because you have been attempting to show why there may be a way in which we can look at thermodynamics, the second law of thermodynamics and other aspects and begin to understand how, rather than going towards disorder, systems could actually start to create order in the midst of otherwise disordered systems. Because this is what life is, it’s about increasing order and complexity, and moving towards these different aspects that we said earlier that life seems to exhibit of being able to do adapt to its environment, being able to replicate, being able to harness energy. And that’s one of the key things that you’re working on. So, tell us about this, what is it that you think you’ve discovered from the physics you’ve done that can be applied, you think, to the very first moments of when life may start to assemble? What was this key insight that you had?

JE: I think that responding to the context, you’re talking about the second law of entropy and disorder, the way forward that I’ve tried to argue for, which I think is really just born out of a renaissance that we’ve seen in how theoretical physics has been talking about thermodynamics in the last 20 years or so, is to maybe shift in the direction of talking about the probability of things happening in, as Paul points to an open system, and not get too wound up in the question of thermodynamic functions like entropy, that as again, Paul referred to, date from a period when people were thinking about thermodynamics, in very different terms, in very macroscopic terms, you know, big heat engines that you can grab on to, as opposed to the somewhat random but somewhat predictable, likely, or unlikely events of what molecules are doing when they’re bouncing around together. And I think what’s very helpful when you start talking about likelihood of things happening in an open system, in a system where you have energy and matter are constantly flowing through it, is, you end up having to think in particular about how the matter that’s in the system, which is what you’re interested in, that’s where the order you’re trying to explain is going to occur, how that matter receives the energy that’s flowing through it, and how that impacts how it changes over time. How would that impact its evolution. And so, this is a different way of talking about the same physics, which is totally consistent with other languages that we’ve developed, that maybe are better suited to other kinds of systems and which I think really maybe makes it more intuitive to pose the same kind of question and see a way forward. The basic idea is just that when you have a system, an open system, where there’s some source of energy in its environment, or that’s driving it, that’s pushing energy through the system, energy is just either motion, or the potential for motion. The whole concept of energy was invented in Newtonian mechanics to explain how things can cause each other to move. And so, you don’t need to think of it as something more than that in these terms. But what is really key is to recognise that the same matter, the same collection of particles will be a different receiver for energy in its environment, depending on what shape it’s in and also, depending on how it’s moving. So, if I, if I think of my working material in my system, I’m trying to understand is having a library of different combinations, we were talking about complex chemistry before, there are many different ways I can put the same building blocks together. I can use the same atoms to make a whale, or a pine tree and I just have to put them together differently, right? So those different ways of putting them together make them differently constructed receivers for energy in the environment. But the key thing is that energy not only gets injected into you in a way that depends on your shape, but it also helps you change your shape. It also is the catalyst for transformation. So, when you have this vast space of possible combinations of building blocks, and you have an open system where there’s a source of energy in the environment, that’s going to be dumping energy into the system differently depending on the system’s shape, that’s going to allow for a biased evolutionary exploration of the space of possible shapes where you start in some random shape, some inanimate shape, but then how you’re shaped affects how you absorb energy and how you absorb energy affects how you change your shape. And when you close that loop, it actually has some of the same character of what we think of as the Darwinian process. In fact, it’s a physical generalisation of the Darwinian process, which is a special case of this picture. So, you can still end up with a specially fine-tuned relationship between the pattern of the environmental energy source and the shapes of structures that form once you start thinking about in thermodynamic terms, how energy flow is going to affect the probability of the exploration of the space of shapes.

JB: So, Paul, what do you take away from that? You’re familiar, I think with Jeremy’s work, but how would you explain this to a lay person? What would be the sort of language you would use for that?

PD: Well, I think the most important message that we take away from what Jeremy just said, is that although at the molecular level, we tend to think of it as being chaotic. We have these fluctuations, that life is anything but chaotic, it’s constrained energy flow. And when you look at these more subtle and complex processes at the molecular level, you see that in this great space of possibilities, which seems almost infinite, it’s actually narrowed a great deal just by the physics. Now, for me, this is an important part of the story. But the part that I’m interested in, as I said at the outset, is how the information management, the information flow, and replication comes to exist. And in particular, how encrypted information, because life as we know it is based on two very different classes of molecules. We have nucleic acids, DNA, the famous double helix molecule has the genetic information needed to construct the organism. And then we have the amino acids, which are the building blocks of the proteins, which sort of carry out all the work. And these are different classes of molecules, and they don’t deal directly with each other. There’s an information channel between them. And so, DNA is written in a four-letter alphabet: A,C,G and T. And people are generally familiar with that these days and 20 amino acids that make up proteins, and there’s a mathematical code that the genetic information is encrypted in and is decrypted when it comes to the formation of the proteins. And all of that, it seems to me, requires something in addition to just the physics that we’re familiar with going on at the molecular level. For most of my career, I should say, if you’d put me on the spot, I would have said that known physics explains life. This is an important point when I say known physics, because if you ask a physicist, most physicists, can physics explain life, they will almost always say, yes, and I agree with that. Physics can explain life but can known physics explain life. And I have come out in this book with the point of view that we do need some new physics. There is new physics lurking in living matter and if you ask me to characterise the physics, it is something that is interweaving the hardware and software aspects. It is fundamental physics that is bringing in information as a key physical quantity, not as an abstract thing that we can talk about in human discourse, but actually is a physical variable, entering into not just a new law of physics, but as Schrodinger described it many years ago, a new kind of physical law. He said, we must be prepared to find a new kind of physical law prevailing in it. And I believe that there is a new kind of physical law, I don’t think we’ve got all the details worked out. And I just give so I ideas in, in the book as to the type of physical order that might be, and I’m open to the fact that might involve quantum mechanics and other things. So, I don’t disagree with anything, Jeremy said. I think it’s important that we get away from this idea that there’s sort of an infinite universe of possibilities and life does something miraculously restrictive, like that, I think there will be natural restrictions arising from the physics, but at some stage, we have to get the software into the picture.

JB: Jeremy, coming back to you, given that the large issues that exist around, how do we get to this point where we’ve got this extraordinary complex code and everything else that that’s required for life to get going. Again, this will have to be in bite sized layperson’s terms, but how do you see what you’ve seen in terms of the way that physical systems can in some sense learn to adapt when it comes to shapes that are more energy efficient and start to use energy more efficiently? How does that kind of get you to that point because it feels like that might be the very starting points of something that might turn into life, but it still feels quite a long way to me from the complex sort of processes that Paul’s been describing in the code that’s involved there?

JE: I think it’s tremendously challenging to take life as we know it and look at what it’s good at, and try to turn the clock all the way back, because it’s so extremely optimal, optimised or made to be extremely good at a particular kind of activity that is in a particular sort of niche, where a bunch of things work together at this point, that it takes great imagination to go back to the full range of options that might have been tested or explored when things were much less settled. And I mean, you can think of analogies to that like looking today and how we use laptops or smartphones to communicate, and all the ways it’s possible even to communicate, right? You can use smoke signals, you can use knots, you can talk to people, you can write them letters. And if you look today, at the amount of communication being done, using the most advanced technologies that we have for that, it could easily kind of drown out your sense that there are other, and in some cases less complex or lower bandwidth ways of communicating. But there are, in fact, a great diversity of such ways. And I think that turning the clock back on life and sort of trying to roll things back before DNA, obviously, it might strain our imagination a bit. But I think that DNA is an interesting example because even the question of what DNA is for, we bring our own end of state biases in thinking about what it’s doing. Because when we think about DNA, as it was discovered, it was a message that was supposed to be copied. And we think of it as sort of the instruction, or the plan for how the living thing is to be built, that has to be communicated from one generation to the next. And we discovered it as the heritable message. And so, we correctly talk about that a lot when we are talking about the functional purpose of DNA. But it’s also interesting to think about DNA and the role that it plays in a single cell. That even if there were no other cells in the world, and you never heard of self-copying, DNA is also remarkable in a different way that I think Paul is quite aware of, and is really getting at by bringing information into it, because of its role as a coordinator of what’s going on, right? That it’s a very small number of atoms in the cell, which if you make small changes, seemingly to the whole overall structure, you can have huge consequences for all the other molecules in the cell are going to do. Whereas if you took the proteins of the cell and made analogously big changes in their structure, you wouldn’t even notice it would be like a fly buzzing in a hurricane. So, DNA has this outsize controller, or sort of regulatory influence. And there’s a very regimented structure to how it exerts that influence. But I think it is interesting to think about how you could see more primitive versions of that kind of emergent relationship between a subset of the atoms or pieces in the system, to what the collective as a whole is doing, that you could get well before maybe you have something that lends itself to self-copying, and to being part of the whole evolutionary process that includes Darwinian selection so well. And it’s a very big chasm to bridge essentially. And it looks very different if you start from inanimate and try to look at like, what’s the first thing that kind of resembles what DNA is doing, even before I have a self replicator, versus if you’re trying to come from the other side and say, let me look at living things. Let me think about what comes right before DNA when I just am about to get what I would call a full-blown living thing. That is a very big bridge to build. But I think it’s something that we should be thinking about. And the last thing I’ll say, on the topic is that I very much agree with the idea that Paul’s bringing into this that information processing is going to keep on being an important way of carrying forward our understanding of this topic because, in what I was talking about before with transduction of energy flow, and how it’s important to bring about organisation in the system, the whole question of how much information there is to process and how much predictability there is to compute about the environment that’s dumping energy into you, is quite important to the question of whether systems by the mechanisms that I’m proposing are able to get into orderly states. We had a paper that came out in Science Magazine a few weeks ago actually with piles of simple robots that are just kind of flapping their arms and banging into each other. And they get into these organised dances. But how organised the dances are able to be, although they’re very kind of emergent and evolved and discovered in ways that you can describe and define clearly in the context of the paper. How organised they’re able to be depends on how much information essentially there is in the pattern of the way the robots are flapping their arms. And so, it does pose this question of where the kind of first seed of structured information is going to come from, that’s going to bring about fine-tuned response and the organisation of the matter that it comes into contact with. And I think there’s more to be said about that. But I agree that it’s a very key issue.

PD: Jeremy raised a very interesting issue, which is that something must have come before DNA. That we can imagine systems which are simpler, systems and molecules which is simpler, which might be easier to understand, which would be some sort of precursor or intermediate intermediary state on the pathway from chemistry to life. And one very popular idea is called the RNA world. So, RNA is a molecule much used in life, and at the moment famous because of the vaccines being developed for COVID. And some origin of life people think that RNA preceded DNA, and this is called the RNA world theory. And I don’t think myself that that really is quite easy. But the point about RNA is that it has this very interesting property. I mentioned that life is based on these two classes of molecules, you’ve got like DNA is the informational molecule in a four-letter alphabet and then the amino acids build the proteins that sort of do all the work. And that’s where the functionality lies and that’s a 20-letter alphabet. And it’s famously, this chicken and egg problem famously said, you can’t have one without the other. But how do they both spring into existence together? Well, RNA has some protein likeability, as well as some information on the mobility. So, it’s got the hardware and the software in the same class of molecules. And so now we can begin to think of some sort of chemical feedback system where the hardware and software feed back into each other, and sort of bootstrap each other. And, I said earlier that I think that somewhere along the line, there has to be some new physics of work, where we bring information as a physical variable into the system. And I think it’s something like that setting, where we have an ensemble of molecules, a whole class of molecules, representing both hardware and software, where we will find emergent laws that entangle the two and I’m using that word not in the quantum sense, the technical sense, but just that the hardware and software are feeding back on each other. So that was an important point, I don’t think DNA just sort of sprang into existence. Something, a lot of things must have come before it.

JB: This information issue seems quite critical, Jeremy, and one particular group that is interested in the questions of origins of life are those who are involved in the intelligent design movement. Now, we’ll maybe come on to talk about theological aspects of this whole debate as well in a moment’s time. But I have read some friendly critiques of your work from that particular side of the aisle, suggesting that maybe there are some ways in which simply thermodynamic forces and the way it interacts with different molecular structures can get you to something that starts to approach some sort of organised systems and so on. But, as one person said, it’s possible in principle, but impossible in practice, you simply aren’t going to get the kind of environment in an early Earth situation where you would be able to sort of amass the kind of amount of information before it quickly degrades again, for life to get going. Now, I don’t know, is this the kind of thing where again, it is possible in principle, but are the odds stacked against it? What’s your sort of answer to those who say, you can’t get information just from a physical process in that way?

JE: I don’t want to speak in too much generality, because I guess the devil often is in the details with these kinds of arguments. But I think when that argument is made, with an appeal to intuition, it’s easy to make it sound like a reasonable claim that maybe it’s just too unlikely. But in the examples that I’ve encountered thus far, where it’s possible to dig into the details and try to develop a more specific theoretical study of that question in a particular context. It doesn’t seem to me like that’s the difficult thing. And I think that one of the things that maybe is hard here is, and this gets back to what I was saying before about the question of where the sort of first information comes from that brings about order in the rest, is that one person’s information is another person’s noise, right? That if I showed you 100 randomly chosen barcodes. those randomly chosen barcodes are clearly in one sense, very different than most other possible barcodes of that same kind that you could make, right? A barcode let’s say has 100 choices of whether to be a black line or a white line. So that’s, you know, 100-coin tosses if you’re making random barcodes. So, you could have two to the 100 different possible barcodes, which is a very big number. And if I only showed you 1000 of them, or even a billion of them, that’s a tiny fraction of all possible barcodes. So, on the other hand, if I just start showing you a billion randomly chosen barcodes, you’re not going to be able to see much that’s interesting in them. They will seem like they were chosen randomly because you don’t have kind of a theory of what they all have in common with each other. So, you have many situations where something on the one hand, can be highly correlated, highly specialised, highly separate, and different than a truly random sampling from all the space of possibility. But where, unless you have already kind of latched on to what’s particular and special and different about that subgroup, it’ll appear to be random to you. And I think that often is hiding in the background in some of these discussions, because really, when we’re talking about information and fine tuning of relationship between that or in an environment or adaptation or things like that, what we care about is the likelihood of being in some shape over here with the matter that we’re interested in with respect to the particularity of the environment, or the source or the driver that’s bringing that about. And so that driver could be randomly chosen at the outset. And then we actually have a paper that’s really about this, you take a bunch of random barcodes, but they’re still a small fraction of the total possible random barcodes, right? You take a small fraction of that, but still many random barcodes, and you start showing them to a collection of interacting matter. And over time, the dynamics of that as it sort of bangs around with the forces barcoding it over and over again and pushing on it in different random ways, becomes adapted to that particular set of barcodes such that if you now start showing new barcodes to the system, you get this big spike in activity and the energy absorption changes. And in a sense, the system has learned that its environment has a certain pattern to it. And then when the environment has changed in a way that we wouldn’t recognise, because it would just look like another random barcode, the system that’s evolved in that environment has a response that demonstrates its detected the difference. So, the barcodes at the outset can be randomly chosen, they don’t have to be specially designed or have a particular pattern to them. As long as they just have some, what within a physics term we call quench disorder, that there’s some randomly chosen initial factors that have gotten nailed down and now that’s sort of like a knobbly substrate of a particular random shape that the rest of the matter has to deal with. And I think that’s the thing that we can start to think about in terms of, you know, the origins of life kinds of discussions as well, because it’s true that once you live in a world with DNA, and RNA, and there are all these relationships that form among those pieces, we can say that the DNA sequence here looks highly specialised to accomplish this, and the RNA sequence there looks highly specialised to accomplish that. But at the outset, it might be that all you need to kind of catalyse the first process of deepening of fine-tuned relationship on the molecular side on the DNA/RNA side, you might just need an environment that has particular fixed facts about it that could have been generated, so to speak much more at random, like there were some supernovas, and you got this much carbon and this much nitrogen, etc.

JB: I’ll be interested in Paul’s response to this as well, but even as you’re speaking there, it’s very natural, isn’t it, when we’re talking about this to almost anthropomorphise the process, and say the environment wants to find, all the chemicals want to do this. And that’s where this whole thing causes me so much confusion because there’s nothing about inert chemicals and physical forces that says, we want to get life at the end of this process, and yet, that’s what the process is, as far as you’re concerned, Jeremy seem to drive it towards. It wants to find ways to harness the energy and to become more efficient, and to then start to replicate itself in these patterns and so on.

JE: Well, just to comment on that, I think what it’s about is whether you can argue for something that looks like an optimisation principle that comes from simpler rules of how everything is behaving. So, in the Darwinian case, the optimisation principle we have is, we have things that copy themselves and so if they’re able to successfully reproduce, and that happens over and over again, and then they pass on their traits to their progeny. And so, you end up getting this optimisation principle where you’re optimising being good at surviving and reproducing, right? In the material context, in the more primitive kind of physical context, you don’t have an argument for doing that, but you do find that from very generic physics, you can get optimisation principles, that also end up producing behaviours that in their endpoint end up looking like they wanted to do something. So, you can take very primitive physical circumstances and say this thing is trying to minimise the amount of energy per unit time it absorbs from its environment. It’s very easy to make a physical system that works that way. So, if you have many building blocks, you have a complicated pattern in some external forcing that it’s getting from the surroundings, then being good at not absorbing energy is actually a pressure to find a very special particular shape that has that property and that looks in a sense, like machine learning, right? Machine learning is just a different way of searching a high dimensional space of possibilities to optimise an input output relationship. So, if you have a particular pattern, in your environment, and you’re trying to adapt a relatively primitive physical property to that pattern, but you have a big library of combinations of building blocks that can do that. You can get something at the end, it looks like you’re just trying to do that. And so, it evokes the idea of function or design almost automatically.

JB: You obviously Paul, also believe that there’s some kind of physical principle you say, it might require finding a new physics, but there’s a principle at work in the universe that seems to drive things in the direction of life. Things won’t just remain inanimate matter if it’s possible, if you like, for the circumstances to allow them to go towards life now. Now what is that for you? What is it that’s doing that? What’s at work in that case?

PD: I should say right at the outset, that we know of no such principle of directionality in the universe. So, these days, there is an assumption that many scientists make that life is somehow written into the laws of the universe, that the universe is rigged in favour of life. And so, give them enough planets and enough time and so on and life will out. That the universe will be teeming with it. That wasn’t the case when I was a student incidentally. Then the assumption was that life was a stupendously improbable accident, it would have happened only once in the universe, and we are it. Now, from my point of view, I would like to believe that we live in a universe which is rigged in favour of life, where there is a life principle where there is something that coaxes matter to life against the raw odds that you will get just from shuffling molecules, but we haven’t found it yet. And that’s why I put such importance with things like this interface of the hardware and the software because there is a principle like that, that’s where we’re going to find a new physics, that’s where we will find the life principle. And that’s one way of finding it. The other way is to discover a second sample of life. So long as we’ve only got one type of life, it’s possible to argue, well, it was just an incredibly unlikely accident. But of course, we’re witness to it, because we’re the product of it, and you can’t conclude from the existence of life on Earth, that there’s going to be life throughout the universe, it just might be an accident. But if we discovered just one other sample of life, just a single microbe of life, but not as we know, that would establish that there is a high probability of non-life turning to life. We don’t even have to go beyond Earth. Obviously, if we ET, or if we even find a living cell on Mars, which didn’t get their Earth, then the case will be made. But we can find life on Earth which is so fundamentally different from life as we know it, that we would attribute a separate origin. So, if the transition from non-life to life is indeed something that occurs from high probability, we would expect it to have occurred many times over right here on our home planet. And how do we know it didn’t? Has anybody actually looked? And it turns out that almost nobody has bothered to look for – I’m talking microbial life only – for microbes, which are not based on the usual sort of DNA, RNA, protein at least not on the alphabet, not on the genetic code that known life uses. And that would establish the point. We’d have two forms of life on Earth, and we’d say, right, there must be some sort of life principle. So, this is why I attach such enormous importance to discovering either a second form of life on earth or life beyond Earth, which has arisen from scratch independently of life on Earth, because then it establishes existence of a principle that is not there in physics, there is nothing in physics, there’s nothing in chemistry that says, that matter has to organise in the direction of goal-oriented behaviour, which is just what existence described.

JB: And if we did discover some evidence that there is life elsewhere and that life was something that happens for some reason in the universe, and that life on Earth isn’t just some massive cosmic fluke, where would that take us? Would we have to say, well, we just need to find the physical principle, the materialistic explanation of this? Or does the door open potentially to those who would say there has to be some kind of purposive agency, some kind of life-giving essence or mystery at the centre of the universe that maybe takes us beyond the bounds of physical science?

PD: I think I would go as far as saying that if the universe is teeming with life and we may not be the best representative of it, but it would mean that life is a cosmic phenomenon that we ourselves are part of a grander scheme of things, and words like meaning and purpose come to mind. But of course, you have to be very careful as philosophers will tell you about how you use those terms. We’ve come from the realm of human discourse and we’re projecting them onto nature. But nevertheless, it’s that sort of thing I have in mind. What I usually say is that if there is this sort of pro-life principle, then there is a coherent scheme of things of which our existence is a part. So, it embeds us in the cosmos in this broader context. Now, that’s not quite the same as religion, some people say it’s a sort of religious flavour to it. But I think it’s something that gives human life meaning in a rather abstract sense, but it gives us a cosmic meaning. But I would fall short of labelling that purpose. But no, I think it’s really important if we can establish the principle of life.

JB: Coming back to Jeremy, you’re obviously an orthodox rabbi, and you do believe in God. But in a way, I could imagine people, you know, a naturalist, an atheist seizing upon your work and saying, well, look, Jeremy’s showing that there’s a sort of very naturalistic principle at work here an organising principle embedded in the basic physics, if you like. So once again, no need for any additional explanations like God for life or anything like that. How do you approach that whole question?

JE: So, that’s another one of those where it could be a very long discussion if we wanted it to be. I think maybe the first thing to say is just getting back to what you mentioned at the beginning with the funny story with the Dan Brown novel, I think because of the plot of that novel was geared at essentially taking the idea of a physical notion of the origins of life and running with it in the direction of saying, science has disproven the value or meaning of biblical religion, and now what does the world do afterwards? What that experience, one of the things that it did was it kind of goosed me a little bit into thinking about how I would write about some of these ideas, if I were going to talk to the broader public in long form, and try to teach about them, because I think I had already been mulling over the idea of writing a book. And then I think what it really reminded me of is that I shouldn’t pretend to be naive about what people are going to do with ideas like this, and that there will be a lot of interest in in saying, oh, so we have yet more proof that God is dead, because someone has moved the marker forward in a certain kind of line of scientific inquiry. And so, I thought, then, what I want to make sure to do is when I wrote a book about this, I don’t want to pretend that I don’t have thoughts about it, or I don’t have other kinds of commitments or other sources that I want to bring into that discussion. Because it is a broader one, it’s not only the narrow scientific discussion. So, in this book that I wrote and that came out, I guess, in the last quarter of 2020, that you referred to at the beginning, every life is on fire. I tried to, on the one hand, write a book about the physics of life, like self-organisation and try to do that sort of straight down the line and talk about it as I would being a physicist trying to explain these concepts in ways that are accessible, maybe to a broader audience. But at the same time, I deliberately interwove it with a parallel set of commentaries on a passage in the Hebrew Bible that I think actually contains a reflection on what living things are as combinations of inanimate materials, and how lifelike behaviour comes out of that. And so, I wouldn’t want to say, oh, look here, you know, if you peer into the Torah in the right way, you can kind of extract scientific conclusions from it. I don’t think that that’s a sensible way of reading the Hebrew Bible. and I also don’t think it’s a good way of doing science. But it was important to me to try to provide an example of how you can take both ways of contemplating the material basis of life seriously, and do so in a harmonious way where maybe the perspective of the biblical commentary almost gives you an opportunity to teach some of the concepts more clearly, and at the same time also helps you situated in a context of broader discussion, and reminds you that science isn’t going to give you the answers to some of the questions you might be inclined to ask.

JB: Yeah, I mean, in that sense, when you see evidence that life could have arisen by some natural process, that we don’t have to have a God who is sort of tinkering with the parts as a miracle essentially, in order for life to arise, that doesn’t in any way impact your belief that there is a God behind the whole of creation? How do you put those together? Do you just say, God is the one who instantiated this kind of a universe in which physical processes will eventually produce living organisms?

JE: I guess again, big, long discussion that could follow such a question. And I don’t want to pretend that anything I could say could exhaust even what I might have to say on the subject, but I think there are at least two things that one could say in brief. One is that, to me, if I think of the use for which the text of the Torah and more generally the Hebrew Bible was created, one has to think about what kind of an activity it’s trying to get someone to engage in. So, I can look at the digits of pi and say they’re true, if I am using them for the right purpose, right, if I’m trying to compute the area of a circle, that’s going to help me if I’m trying to use them as a phonebook, that’s kind of an absurd way to use the digits of pi. It’s also absurd to use the Torah as a phonebook. And I think sometimes when we get into these confused discussions about science and religion, there are similarly absurd uses that people are taking as the intended use of the text. And then there’s sort of confusion about the use of the text that’s agreed upon by both parties to that dispute. So, they kind of draw a line of scrimmage, and agree to misuse the text and get confused about it. Or at least, sometimes the most fractious kind of versions of that discussion appear that way to me. I think the way to understand the goal that the Torah and more generally, the Hebrew Bible has is that it’s trying to catalyse the mission of a servant of God. That it’s trying to advocate a way of talking about human experience and say, take the data of experience, take what you perceive in the world, and put this interpretive frame on it and let that be a way of guiding your activity. And if you’re going to use it for that purpose, this is the language in which it’s going to talk about what the world is. This is the language that’s going to enable you to navigate that mission or to pursue that mission and navigate the world in which it’s going to be pursued most effectively. That doesn’t mean there aren’t other languages with which you could talk about the same world. And in fact, we’re even told that at the beginning that when God says, let there be light, and there was light, one of the points there, the speech coming before the light itself is that the light by which we see the world comes from the way we talk about it, right? So, we have different ways we can choose to talk about the same world, even physics and biology fit that description. And we’re going to succeed depending on what we’re trying to do, depending on whether we match the activity we’re undertaking with the language we use to characterise things. So that’s a very kind of high-level reaction. And the thing I would just add in brief on top of that, is that I also see particularly within the Jewish tradition, and the relationship that it has, since ancient times sought to have in large part with its text, the notion of whether God is there is not so much a fact to be empirically tested, but more like a covenant or a commitment that you choose to become a party to. And so, I think that it’s not a matter of proving or disproving the existence of God, but more saying, let me walk the path of someone who has chosen to use this as an interpretive frame for experience, and then ask the question, do I find that this is guiding me as I walk that path? Am I finding it a useful interpretive frame, in the same way that assuming that other human beings have conscious intentions, and that they’re possible partners in communication is actually an interpretive frame I could choose or not choose to impose on my experience, I also can make that choice with respect to seeking a relationship with the creator of the world and it’s not as easy, and it’s much more complex, and one needs guidance that I think these traditions seek to try to provide. But that’s the opportunity there.

JB: Paul, we are starting to approach the end of our discussion. But one thing that I’ve been wanting to ask you the whole time really is, is where you feel you stand on the sort of religious spectrum, I think you’ve described yourself as not conventionally religious, but that doesn’t seem to rule out a sort of religious dimension to you. Because I don’t get the sense that you’re a sort of reductionist atheist, you know, it’s all got to be explained by pure physical material laws. You do sense that there’s some great mysteries, but what might that actually look like when it comes to, I don’t know, is there some kind of an agency behind the universe, is there something pushing things towards this to consciousness and life and everything else? Would you be willing to share?

PD: When people ask me about my religious position, I normally start out by saying, well, it’s not this and it’s not that and so on. So, I don’t like the idea of miracles. I don’t like the idea of a God who sort of meddles in the affairs of the world. And also, I don’t like the idea of a God who’s sitting around for all eternity and then made the Big Bang, go bang at some arbitrary moment. And so, I think, however, we live in a universe, that is remarkable in many ways. The laws of physics themselves, where did they come from? Why do they have the form that they do? Most of my colleagues just accept them as a brute fact, but it seems to me that there should be a deeper level of explanation, I’m not sure that God is an appropriate term for that. But if part of what is involved in the laws of physics is something like a life principle, then what we’re talking about is something that explains the order of the universe, and our place within it. What is undeniable and you can’t be a scientist without supposing that there is a rational order in nature that is, at least in part intelligible to us. And I just like to say a few words about that second aspect, intelligibility. Einstein once said that the most incomprehensible thing about the universe is that it’s comprehensible. People will often shrug this aside. Scientists themselves will shrug this aside. Of course, the scientists can understand the universe because they’re paid to do that, that’s their job. They find it no surprise. I think it’s absolutely staggering that the human brain, which has evolved to survive in the proverbial jungle, has within it the ability to decode nature in this thoroughly deep manner, that is, typified by theoretical physics. Many animals are better at jumping streams or catching objects than we are. When Newton saw the apple fall, he didn’t just see a falling apple, he saw a set of differential equations that connects the motion of the apple to the motion of the moon. And likewise, in decoding nature through science, through science and mathematics, what we’re finding is hidden linkages that are not apparent to any other organism that we know. In other words that we have tapped into this deeper substructure in nature. Some people call it the cosmic code, we talked about the genetic code, the cosmic code. We can decode the cosmic code and we’ve done splendidly well. Now, that doesn’t mean that we understand everything, there are still some gaps in our knowledge. But when you think about the last 300 years, our advance has been enormous in comprehending the world. So, we were talking earlier about the sort of directionality in the universe going from matter to life, to consciousness, I would add comprehension to that. There’s a sort of an arrow of time in the direction of comprehension. And if that is the case, if this is not just an enormous fluke, a happy series of accidents, if it can be established, that that is a general tendency, then that to me comes very close to something like a meaning or purpose in nature, and certainly a directionality in nature in the certain scheme of things. But it’s a scheme of things that we can come to understand. And so, I set huge store by this ability to do science and do mathematics, the comprehensibility of the world, I think is the absolute key to there being something deeper behind it. And it’s something that we as representatives of comprehending organisms are tapped into in a very fundamental way. So, I think that’s a sort of religious feeling. What Einstein called a cosmic religious freedom.

JB: Yes. In that sense, often obviously people put science and faith at odds with each other, but it sounds like there’s something beyond just the raw natural material of science and so on that you feel needs investigating and perhaps we never will fully understand. But I suppose it’s very fundamental that we are here to do it and that required life to get going and that required us to be here as observers who can ultimately look at our origins and look at our universe and comprehend, and as you say, it’s mind-blowing in a way that we’ve got to this point. And seems you could argue is crying out for an explanation of why the universe does present itself as so intelligible to us. I mean, a cheeky question perhaps to finish with for you, Paul, but what would it take to convince you that this isn’t just a great mystery, but potentially a personal agency, a divine mind, a creative mind behind the universe. I mean that may raise more questions than it answers for you, but what would take you from just this being a huge mystery to be enjoyed to something that could even be experienced as many religious people obviously feel they do?

PD: Yes. I’ve never had a religious experience; I won’t ever have one. What do I say to people who have had them? It’s like, when people say, I’ve never been in love and you say, well, it’s a very real thing, a very real experience. So, you can’t just shrug it aside just because it never happened to you. But I suppose at the end of the day I always put my physicist’s hat on and think, well, the default we’re talking about is something where God or some agency or something supernatural, something that transcends the universe, somehow then zeroes in, and does something, it gives me an experience or if it was a miracle or something extraordinary happening around me, that’s not a type of God that I feel very comfortable with. As one English bishop once described it as like a laser beam God. So, you know, what would convince me? It would have to be some direct experience and at this stage I haven’t had that. So, what more can I say?

JB: Jeremy, any final thoughts to add from yourself, I suppose, speaking as a rabbi, just as much as a scientist, as we conclude today’s show. Obviously, I’m sure you’re very sympathetic to the way Paul sees that there are these deep mysteries in the universe, the way it is so intelligible that seems to sort of suggest some something’s going on that needs a bigger understanding, a bigger picture maybe to put together than just physics alone.

JE: I would agree with that. I think that one of the things that, in this kind of a discussion, I find it important to emphasise is that our capacity for understanding and making sense of things about the world is very powerful. But it always relies in one way or another on our own constructions in how to represent the subject at hand. So, we devise things like laws of physics, in order to, sometimes extremely well, but still, to approximate the predictability of the experience we perceive. And I think that even the greatest successes of theoretical physics should be thought of, like in the category of, let’s say, today’s most powerful microscopes where in order to turn the data that you collect with a raw device into, let’s say, the image of the very tiny thing that you’re looking at. But there’s a huge number of assumptions and interlocking kind of implications and calculations that turn, what you’re getting from interacting with the world into a representation that is sensible, and it seems to represent something that is illuminating in a certain way. And the reason I think it’s important is because what it means is that even our most successful theoretical constructions: general relativity, Newton’s laws, what have you, you should think of them as being very accurate and very successful and very valuable. But they’re nonetheless a choice of a medium of representation, much like taking a black and white photograph of a rainbow, right? So, I could take a black and white photograph of a sky with a rainbow in it. And that could reveal highly accurate information to me about my subject. And yet, it’s obvious to us that in our choice of that mode of representation, we’ve eliminated totally from the medium of communication, or the setting where we’re making the representing the thing, the possibility of seeing other things that also were there if we had just perceived it differently or represented it differently. And so, I think what that points to is just the importance of having humility about the kinds of approaches we can take to making sense of the world. So, physics and mathematics is one kind. And we can make tremendous strides in figuring out certain things about the world. There are other things about the world that are not best predicted or described or understood in terms of mathematics and physics. And the moment we substitute a limited model of our own construction, for a full-blown picture of reality, and all it is, that’s kind of lifting ourselves too high in some sense and thinking too much of our own creations. I mean, I think it’s actually quite related in a sense to the biblical idea of creating an idol and what the problem or the danger of that is, that it’s overly investing authority in your own construction and the work of your own hands. And so, I think that, in one sense, I completely agree that there’s a tremendous amount we can and have understood and more that we still can’t understand with the kind of representation that maths and physics allows. But I would argue for a more expansive view of the kinds of languages we need to capture everything that’s true about the world.

JB: Probably a note of humility is a good place to end this show on. Thank you so much, Jeremy and Paul, for your time. If you want to find out more about these subjects and go into greater detail on issues around the origins of life, The Demon in the Machine is the book by Paul Davies. Jeremy England’s book is Every Life is on Fire. And I’ll make sure there are links from today’s show where you can find out more about both my guests, but for the moment, Jeremy and Paul, thank you very much for being with me.

JE: Thanks very much.

PD: It’s my pleasure. Thank you.

Transcript ends 01:25:55