The Origins Podcast with Lawrence Krauss - Martin Rees

Episode Date: October 24, 2019

In London, Lord Martin Rees joins Lawrence to discuss cosmology, science writing, politics, and the role of religion (and religious figures) in modern society. See the exclusive, full HD videos of all episodes at www.patreon.com/originspodcast immediately upon their release. Twitter: @TheOriginsPod Instagram: @TheOriginsPod Facebook: @TheOriginsPod Website: https://theoriginspodcast.com Get full access to Critical Mass at lawrencekrauss.substack.com/subscribe

The Origins Podcast is supported by listeners like you. If you enjoy the show, please consider supporting it on Patreon. Subscribers also get access to full video of each episode, as well as bonus content and exclusive perks, science and culture. Together, visit us at patreon.com slash origins podcast. Hello, and welcome to the Origins Podcast. I'm your host Lawrence Krauss. Lord Martin Rees is one of the most distinguished astrophysicists in the world.

When I entered cosmology after a background in particle physics, I had to quickly determine who I could best learn from and which papers were reliable. And I honed in on Martin for both purposes. As I got to know Martin more, I discovered what a voracious reader he is. He seems to read everything that comes out in science. And he's devoted some of his own time as well to popularizing the field. Beyond his remarkable scientific career, he's taken on many tasks to serve society. He's been the Astronomer Royale, master of his work.

Trinity College, president of the Royal Society, and now he's a member of the House of Lords. Clearly, his interests are very broad, and we are able to have a detailed discussion of modern issues in cosmology, but also about the political situation in the United Kingdom and the United States, and public science writing, and even the role of religion and religious figures about which we don't see eye to eye at all, and you may catch a glimpse of that. Whether we agree or disagree, I come away from every conversation with Martin, both in light, and motivated. I hope you will too. Patreon subscribers can find the full video of this program and all our programs

immediately upon the release at patreon.com slash origins podcast. I hope you enjoy the show. Well, Martin, it is always a pleasure to talk to you. I always learn things and am enlightened. And so I'm going to enjoy being enlightened over the next little while as we chat. And I want to ask you some questions. I've never, remarkably, never asked you in our times together. First of all, I've never asked why you became an astronomer, what interested you as a child or what determined that path? I didn't have that vector early on. As a kid, I was keyed on numbers and nature, etc. And in the English schools, you have to specialize in your last two years in high school. And because I was bad at languages, I specialize in science.

and then I proved you quite good at maths and so when I went to university that's a subject I did and I realised I wasn't enjoying it there were some other students who clearly had the mindset of mathematicians and I didn't and so when I got my bachelor's degree

I tried to think of some way in which I could use it in a more synthetic and synoptic style of thinking which is the way I like to think and I thought quite seriously doing economics because I had two friends who are still friends who started it and they went that way. And just by a chapter of accidents,

I ended up doing after physics in Cambridge. And this was lucky for two reasons. First, I had an excellent advisor, who was a very good scientist and an absolutely great coach, a great coach, if not a great player. He has some very distinguished students. Well, he was lucky, and we all learned from each other, of course. And also, this was a very good time to go into the,

because I started in 64, and that was before the microwave background, first black hole, etc. And I always like to say that if you're picking a subject, pick something where new things are happening or new techniques, because then the experience of the old guys is at a heavy discount. And if you're young, you can start and make an impact fairly quickly. And I was quite lucky in that sense. It's interesting. Let me ask you about I did a degree in mathematics and one in physics when I was an undergraduate.

Yes, I didn't do physics, and I picked that up as I went along. You picked it up pretty well, let me say. I'd done better if I'd done physics and not mathematics at Cambridge. Yeah, well, as a preparation for astronomy, I think, on the other hand, as I tell people, I've learned more since my PhD than before. Well, I think that's true, and I think I was badly taught because no one explained why you might want to diagnose a matrix, for instance. And so it didn't relate to anything that I might have wanted to apply it to.

So I think bad teaching, but I did realize that I didn't have the mindset or the ability of the people who ended up being professional mathematicians. It's interesting to say that. I often say that when I was chairman of the apartment once that people talked about whether it was okay to move the physics earlier because people hadn't taken something called differential equations and a vector calculus. And the experience of all the students who I talked to, including myself, is that you could do that in mathematics. but until you saw it in physics, you really never understood why you were doing it or what. So doing it coincidentally at the same time, seeing how it's applied in the real world,

makes it much easier to understand the mathematics, I think. I think so, except some mathematics people appreciate it for its own sake. Yeah, yes. And I didn't get to the stage of having that appreciation. Did you ever know Dirac when he was at Cambridge? Did you ever, because he was one... I went to his lectures. You went to his lectures?

Yes, in the about 1969, about it last year. and no, 64 might be it. And he lectured for a proof copy of the latest printing of his classic book. He thought he'd said it very well then, why change it? And he spoke in a Raudulway and wrote rather clearly on a blackboard, etc. So he was not inspirational, but it was a living fossil who was great to see. Yeah, great, amazing. But he was one of the, I think one of the few, well, I've known a few physicists who basically

viewed the mathematics and the mathematics illuminated for him rather than the sort of... Obviously, it's very important physics, and his intuition ended up being great, but he was driven by the mathematics and the allure of the mathematics. Well, that's right. He famously said

that the beautiful mathematics was likely to lead to something, and you should follow through the implications of the mathematics, and that may predict some new physics, and of course it did. It did in his case. The positron for him, yes.

Yeah, and you mentioned actually in your recent book, I was reading that. And as we all, that famous essay by Vigner on the unreasonable effectiveness of mathematics, which I sense now we have a better understanding of why mathematics works well for the world. But maybe at the time it seemed more serendipitous. But now when we think of, at least for a fundamental perspective, that we don't think, at least as physicists, we don't think of the equations as so much as the symmetries

that govern the nature of the equations and the symmetries are described by mathematics. So it seems to me to be less, less. surprising or unexpected. But one of the things I learned about you just that I didn't know was your parents started a new school and you went to it when you were younger. I did, yes. And it had a modern, sort of a quote, modern,

what was their modern curriculum or whatever? Not especially modern, actually. It was a school. I had a really fortunate childhood, not so much with the education, although I was well taught, but it was in the wonderful surroundings in the country. So I grew up in a village and having the freedom to roam in a beautiful countryside.

Yeah, which you maintain, right? You now live in a converted farmhouse, right? Right, yes. So you maintain that the rural, the Roussonian. Yes, I could never have it in an apartment. Yeah, yeah, the love of nature, the primal man and the beauty of nature. Okay, well, when did you know? Did you know even when you're pursuing your PhD that this was the direction,

that you were going to become an academic, or was there, at the time, did you think it was a stepping dose on to potentially something else? No, I think when I started, I was diffident and uncertain. But after a year of working as a graduate student, I got enthusiastic and I was convinced that I was going to enjoy it. And therefore, when I got my PhD, I did try to get some. postdoctoral position, and I was glad I did. Yeah, it would manage to do. Was it any specific thing that turned you on, that turned you on and said, this is the right path for me?

I don't think so, because it was interesting, because the micro-backgrounds discovered, and it was possible to have some new simple ideas which were relevant to these. For some listeners, I guess that there was a sea change, and even it was a little early for me, although, yeah, so in terms of understanding the significance, but one of your, I guess, someone who was potentially a mentor of some sort, Fred Hoyle, there was a big debate about whether there was a big bang. And I mean, while the microwave background was discovered, which is the remnant of the Big Bang,

that we now recognize as a Remnant of the Big Bang, was it immediately, I mean, in retrospect, we often make it sound like something immediately changed, there was a paradigm shift. Was there a paradigm shift at the time? Was it immediately recognized as unambiguous, did people change their minds or not? Well, I think in a year or two,

they had had data at different wavelengths to see if the spectrum was thermal, but I think it did convert almost everyone at that time. Fred Hoyle himself was never fully converted. He tried to have elaborate theories, and I would say ended up believing what I call a steady bang, some compromise. Yeah, yes. And, of course, I hugely admired Fred Hoyle,

but I never really work with him because he started to go off in slightly eccentric directions at the time when I'm. I started to be in the subject. But he was a really great figure in the subject. If you look back at all the things he did. He had an immense impact. And certainly, well, these things are always,

I know your view about awards and I share it in many cases. But he certainly, he did work that certainly was on par, and many people could say worthy of a Nobel Prize. Of course. He should have got it for his work with Fowler. But more generally, he was a real polymath and very inventive and made lots of contributions to all branches of astronomy. And of course, but he also enjoyed debate.

And before the microwave background was discovered, there was, as you say, the Steady State Theory was advocated by him and Bondian gold. There were three sort of very noisy and articulate people. I don't think they carried much resonance outside the UK. Oh, really? Certainly not in Russia or not in America either. But in the UK, it was an important debate. And the debate involved the race.

radio astronomers, because they were the first people who found evidence that the universe couldn't be in a steady state, because they found that there was more evidence that radio sources were strong, and that radio galaxies existed, spewing out radio waves in the past than now, contrary to what you'd expect in a steady state. And this was a debate where Martin Ryle was correct, and I listened to these debates and the 60s, and I felt that Hoyle was perverse not to take them seriously. But then I read more history of the subject. I realized that in the 50s, Ryle had been equally dogmatic when he'd been wrong. Oh, I see. And so I understood that Fred had a reason for being somewhat skeptical,

whereas I came fresh on the scene, and Ryle seemed to be talking a great deal of sense, and indeed he was at that time, but he had been dogmatic and wrong. I see. So you It has earlier standoffs with Hoyle and gold. Well, that, you know, brings to mind a bunch of things, but not least that someone told me really wasn't Max Planck that said this. I've always attributed to Max Planck, the famous statement that physics precedes one funeral at a time. Do you know if you're a scholar?

I've attributed to him. Yeah, yeah, yeah. So that young people are not burdened by the biases or prejudices that have come up over time in the past. But, of course, this does raise a question. question of what happens to scientists when they get old. Yeah. Something which is of concern to me and even to you.

And to me, yes. And I think there are three routes. Many of them just do less science, become administrators or synch to torpor in some form. Some overreach themselves and go to new fields. And a Hoyle, Shockley, Pauling and others, Eddington, they're people who they would still say they're motivated by trying to understand the world, but they no longer get satisfaction from the routine stuff they're good at. And they try and do something where they're not experts. So, of course, Fred Hoyle did this sort of thing in his old age, attacking Darwin,

saying that flew up with Debby's came in on comets and things like that. So that's the second way. And the third way is, of course, to go on doing what you're good at and realizing that your work will be on a plateau and you won't get better. And I think it's interesting to see why it's the case for many artists, certainly painters and composers, that their last works are their greatest. But you wouldn't say this of many scientists. The best they could do is say on a plateau. And I think the reason is that if you're, say, a composer,

then you're influenced by the musical environment when you're young. But thereafter, it's just internal development. Okay. Whereas in science, it's a collective activity. You've got to be able to absorb new techniques and new data and new ideas. Exactly. And that's what we get less good at when we get older. Absolutely.

And I mean, they're rare exceptions. Of course, to everything like this, there are exceptions. But, you know, an example of being a famous example is Einstein, who was incredibly in tune with what was current at the time. That's right. But then later on, sort of refused to accept or at least refuse to be in touch with with the key experimental things that were going on. His obsession with unifying electricity magnetism became an anachronism

because already in the 30s we knew there were other forces in nature and it was kind of it was not the you couldn't unify. It was premature to do it. Yeah. But also he didn't really follow through on the implication of his own theory. Yeah, yeah. He didn't work on black holes. Yeah.

And he was in the same place as Oppenheimer for 10 years. Yeah. And Oppetheimer had done this wonderful paper in 1939. which was a step towards understanding gravitation collapse, and they never discussed it, I don't think. That is fascinating. Well, so I guess the idea is to try and keep an open mind and listen, but it gets harder because I think the other problem...

Keep a mind of jarl and not completely vacant. Yeah, exactly. But also, the more accomplished one is that sometimes the sense, I've seen people get the sense that they should, therefore, only be working on things that are profound and important when in fact most of the time when you're a scientist you're working on little things that are interesting you and my friend shelley glasho calls him pieces of grizzle but but but so if you if you're always trying to solve grand problems you rarely make any progress right but only cranks and geniuses

work on the big problems in one go you've got to work in a piece me away yeah yeah although the other thing about hoyle that i do appreciate is he he was a good science fiction indeed he was yes and i mean his first book the black cloud yeah he took more trouble over that and the here is a handsome version of him, of course. Okay, excellent. Well, I first learned about that when I was from Freeman Dyson when we were debating the long-term future of the universe, and he was the first one that we talked about whether intelligence could survive

and a black cloud was an interesting example that he tried to present as a counter-example to our debate. Right, it's the only kind of terms you could have in a universe that was nuclear-free with only hydrogen. Yeah, exactly. Although we both agreed in the end that the future of the universe in the universe that we think we live in now, Black Cloud, you still couldn't have life forever, even in the form of Black Cloud. But we don't know. Good thing too slowly.

Yeah, yeah, exactly. Well, what is the, what was the biggest surprise? What's been the biggest surprise to you in your career in studying astronomy and cosmology? What unexpected thing changed your thinking of the world more than anything else? Well, of course, I came in fresh when the microwave background and quasars were being discovered. I mean, I suppose the biggest thing is really exoplanets. Interesting. I think.

And it's not fundamental because, of course, what's happened is that we understand the Big Bang back to a nanosecond. Before that, the physics is uncertain. And we understand the formation of structure. But we don't understand all the complex structures that form. And I think exoplanet. and it's make the night sky far more interesting and also open up the possibility that we can make exobiology a real science with real data.

With real data, which it isn't yet. That's right. There's a lot of heat, a lot of heat, not yet so much light. Yes, but some of serious experimenters and theories have been motivated to think about the subjects. Exactly, which proceeds a lot of... Because people don't realize that, although we've got Darwinian evolution,

we still don't know what causes the transition. from complex chemistry to the first replicating, metabolizing entities we call alive. My sense is that before we can make extreme progress in understanding life in the universe, we have to understand nature of life here on Earth. I'm not sure. Do you think that what we see and learn from exoplanets will illuminate and help us understand the evolution of life here on Earth? Well, I think we've got to do both. First, I think that the people think about the horizon of life on Earth, which is, of course, a problem that even the most firmly ground-based biologists cares about, they ought to be able to tell us, was it a rare fluke or not?

Yeah. And also, was there something really special about the DNA-R- and a base that we have? Or could there be other quite different forms of life? So I think we'll know that in 10, 20 years. And I also think that we will have some clues as to whether the biosphere as well. We may find something under the ice of Enceladus or even on Mars, but we will, I think, with the next generation of telescopes, have some spectral evidence about some of the Earth-like planets orbiting nearby stars, which will tell us, you know,

are they green, is evidence for an unequilibrium atmosphere, etc. And so I think within 20 years anyway, it's not absurd to think we will have some evidence as to whether there is a biosphere on another planet. Whether we're unique. I can't imagine that the answer won't be yes, but do you agree? Well, I think I bet that there will be a lot of biospheres. It may be more than 20 years before we are convinced of that. Yeah.

But, of course, whether those biospheres evolve into anything like what happened here. Yeah. Anything interesting. Certainly anything intelligent is a quite separate question. Yeah, because we're here by, I mean, there's no evidence that intelligence is an evolutionary puritive or, I mean, we took four billion years on Earth before we had. this kind of intelligence. So yeah, I agree. That may be much more special. But it's hard to imagine given that, at least to me, given that life evolved on Earth about almost as soon as the laws of physics could have allowed, and that the fundamental constituents, water, organic molecules,

and sunlight and energy is kind of ubiquitous throughout the galaxy. I have a hard time believing that life itself. That kind of life itself is. No, so do I. I mean, logically, it could be it was unique here, but it does seem unlikely, I agree. But at the same time, I'm always, I'm a little worried by claims about habitable planets, which are, every time a new planet is discovered and people talk about it being habitable. We really, it's, and the habitable zone is described just sort of where liquid water could survive. But as I like to point out, even on Earth, there were times in our history when certainly the Earth is a habitable zone. You know that, but it's been, but it's been frozen over solid. And so the detailed, the detailed climate,

and it depends on continents, all sorts of things. things which are sort of far too complicated right now to put in the models of exoplanets. So I think it's a, it indeed is a little premature from my point of view. I did make a bet actually with a public bet now, I think, with Richard Dawkins, I can ask you, my bet is that if we find life, not so much I'm worried about Mars because we can pollute, I mean, we're not sure if we're not Martians or vice versa, because life will polluted each other. But if we found evidence of some life under Encelotus or you pick up your plant famous moon,

that I suspect it would be almost identical. I kind of think that life is governed by chemistry so much that even the base pairs, that even the genetic code, I think would be the same four sets. And he thinks it's impossible, but I made him a bet. Well, I don't know why I said that's the second thing we may learn. Yeah. for these others. But of course, if we did find life on a moon around Saturn or Jupiter,

that would be crucially important. Yes. If it evolved twice within one solar system, then it's everywhere. That immediately says it must have happened millions of times in our galaxy. Do you want to take up the bet with me because he's promised an extremely expensive bottle of wine? I'll stay out. No, it'll be interesting to me. I mean, there'll be so many fascinating things.

But on the other hand, if we discover extant or... extinct evidence of life on Mars, I think, and if it was identical, most of us would not say it's independent. I think, in fact, well, there's a possibility that it went from one and the plan to the other. Yeah, I think, well, I think Annie Noel, who's a, who's a, evolutionary biologist, early studies early life on Earth, had said once that he, he would be amazed to not find evidence of our cousins at some level on Mars, but simply because microbes can can travel back and forth. And if they arise on one planet,

they can pollute, they will naturally, I think, pollute other planets. So it'll be interesting to see. The men will survive. Yeah, exactly. Yeah. So, okay, well, that's fascinating. The exoplanets, I think it's really interesting.

So would you say that, well, one of the things we've learned that's most surprising in me about exoplanets and maybe, I don't know you, is that all of our, almost all of our wisdom about solar systems and what it's possible in solar systems has been wrong in the sense that,

things that we thought couldn't exist. Giant, gas giants, near stars. And everyone thought, I mean, the kind of a presumption always is that you're typical. And that, therefore, our solar system is typical. But now we see that not necessarily that at all. That, well, that far more things exist in heaven than it dreamt of our imagination, I think. That's right. And data gathering is going to hugely clarify, allows to classify,

planetary systems. And as they at least, to chemistry and complex, biology perhaps. So I think that's a fascinating subject. But of course, going back to fundamental cosmology, I hope we will understand better the first nanosecond and why the universe expand the way it is, has a mix of constituents, what the dark matter is, etc. And of course, whether our Big Bang is the only one. Yeah, those are big, those are the big questions. And I've become a little more optimistic. In spite of the fact I'm generally pessimistic by nature, I think, although as my friend Cormac McCarthy said,

that's no reason to be gloomy. I used to think there'd be no hope of having any empirical answer to many of those questions in my lifetime. I'm now not convinced. Even the possible existence of other universes, which I thought would always be metaphysics. I think if we, you know, I've written about this too, as you probably know,

that if we can discover evidence of primordial gravitational waves, it may give us enough evidence to understand a theory that tells us, even if we'll never know about them, that the theory tells us how the universe is buying this thing called inflation, we're created. Well, that's one way. But the other point is if we have a theory that applies that tends to 16 G.E.V.

Yeah. Which is about, just for the listeners, it's about 16 orders of magnitude in energy, greater than the energy associated with the nuclei of atoms. Right. And it's the energy which particles had at the epoch of inflation, if you understand the pictures. And if the physics had the properties that are needed to give

rise to Andrei Linday's eternal inflation model, which is specific, then, of course, we would take that seriously if that physics had been corroborated in other ways. Yeah. And so the question is, it might be corroborated by primary world of gratulation ways, but better still, obviously, would be if it does explain things in the low energy world. Of course. Why the three kinds of eunos and things like that. All the things we don't understand.

And if it maybe could be corroborated by trestable experiments underground looking at properties of protons, which I won't go into it yet. But yeah, it'd be nice. Well, actually, it would be really nice because one could point to the other. If a discovery and cosmology is made associated with that, it might point to the kind of physics that one would look for under large underground.

There's a great symbiosis there. You know, I'm still, I think it's a long shot, but it's amazing to me that it's even possible that we might know, without clearly ever being able to measure the existence of other universes, that we might have enough confidence, just as perhaps in 1905,

by 1905 or a little bit after people accepted the existence of atoms, when at the time I think everyone thought we'd never ever be able to see them, but it was pretty well accepted, not 1905, but by 906 or 8. And it's amazing to me that metaphysics, in that sense we become physics, that's always progress. Anytime we can reduce the domain of metaphysics and increase the domain of physics. It's a big jump to get from the scale of atoms to the scale where space and time have granularity. which is a trillion, trillion,

a smaller. Yeah, it's a long shot, but it's... But it's certainly possible. And I think if that's the case, then there are two big questions. You want to ask, does this physics indicate the light of many big bangs? And then also, the other related question is,

do the different big bangs cool down to be governed by the same physics, or are there really many vacuahua? That's the other big question. Yeah, because that changes, it seems to me, the whole question of fundamental physics. When I was growing up, I wanted to do physics because I wanted to understand why the universe has to be the way it is. But in fact, it may be, that could be just the wrong question.

Our universe just the physics may be what it is just for no real, you know, because it could be anything. And we just happen to live in a universe in which we could evolve. Yeah. Just like we happen to be in a solar system of the planet as they are. Yeah. In fact, there may be nothing more fundamental about that than there is about the famous radii of the planets around the sun, which early on Kepler and others thought had some profound significance. It's just largely an accident.

But I think it's interesting that of all the things that I'm fascinated by the exoplanets, which indeed are not from a fundamental physics perspective, surprising, is your biggest surprise because that's fascinating. Would you say that we should then... Perhaps I suppose neutron stars in a sense were a big surprise, weren't they when they came? Yeah, yeah. They were a huge, to find they existed. And, of course, they've kept on for last 50 years revealing amazing new things.

In fact, actually, you've made a perfect segue because I was going to say, recent news, in some ways, is more intimately related to the, to the, some of the, I mean, you made profound, had a profound impact in a wide variety of areas of astrovisic and cosmology. And I've always, I used to, as a, I'll tell you this, and I'll tell you it publicly, when I was a particle, when I didn't know much astronomy and cosmology, I decided, that, you know, there's lots of stuff being written. And what you have to do if you're a young scientist is learn who you can,

who's more likely to be trustworthy and maybe, there's so much you can read. And I always told myself, well, I'll read Martin Reese because, yeah, so just so you know. But getting back to a subject, which, as I say, I think is more related to fundamental work of yours

and this new, I wanted to kick your take on the significance of the new observation, of black hole, which is captured at least among the public fascination, a picture, a reconstruction, not a real picture, but a reconstruction of the image of a black hole. Yes. How did it impact on you? Well, I think it was a huge technical achievement to be able to link together the data from eight telescopes around the world and recover the fringes and all that.

It's great technical achievement. And it's very nice to see the picture. So in terms of evidence for black hole, I think to be honest, it's just a marginal step forward. Indeed, already from X-ray astronomy, we had evidence of hugely Doppler-shifted and gravitated red-shifted broad lines. And well, and also, I mean, one of your fundamental discoveries, if I could call it that, is the fact that basically black holes in collapsing systems would produce incredibly energetic jets, which have also been observed. Well, but they could have come from other things than black holes.

Yeah, but... So we don't know. And indeed, incidentally, if they hadn't found the dark circle in the middle, then the explanation I would have given would be that the jet is... It's pointing to... We know that in this galaxy. Yeah. The jet is 20 degrees away from the line of sight.

And the one thing I was hoping we'd learn from these particular observations was something about the base of that jet. in particular was it wider than 20 degrees. So some is coming towards us. And had that been the case, it would have sort of blinded us to the extent that it would have filled in the hole. Yeah, sure.

And so we've learned something about constraints on the theory of the jets. Was the prediction that it would be not less wide that you, would it surprise you if it had blinded us? Would it have surprised you if the jet was so? Let's make it clear that what we're talking about is that so there's this dark, there's this dark hole. But of course, if there was any,

energetic radiation being emitted outside the black hole, and it was pointing our direction. Of course, it would blind us to what's behind it, which is the black hole itself. Well, I mean, a different theory. And we've done by a number of people. And some would have this property and others wouldn't. Okay. The extent to which the... So something's been ruled out, I guess.

Yeah. Well, then it's made an impact. But what's been ruled out is something which is not sort of deeply relevant to black hole horizons, but it's something which is relevant to astrophysics. and perhaps JET is something I have worked on a lot and one of the reasons why I feel a dinosaur in much of my scientific work is that many of the things that I did were done at the time when the best you could do

is have some simple symmetrical models whereas now because of the far greater power of computers is possible to do realistic simulations of many of these problems and indeed to think of what happens if magnetized gas flows around and falls into a black hole, etc. And that's been a huge advance in the subject. And that's why, if people ask, should they work with me on this? I say, no.

Work with someone who's more adept at coding and understanding this sort of competition. Since we can't do any experiments in astronomy, we can, in the virtual world of our computer, do experiments. And they've hugely advanced our subject. In every way. In fact, I mean, once again, the other major, major advance, the direct discovery of gravitation, the direct, the direct, would have been impossible if you couldn't have, if you didn't have computers that could produce models that would give you what you'd expect to see. So you could compare it against observation. That would

have been totally impossible. So I'd like to say that these observations were not, couldn't have been more timely or even done earlier, not just because the experimental apparatus was only required the advances in optics and everything else we need. But the theory wasn't, adequate. Well, that's right to actually compute objects in a non-fixed space time. Yeah. And it's a big challenge. They came together always.

Well, you know, I think it's nice that it's, I sort of, of course, agree with you. I think it's nice that's captured people's imagination. And anytime people get excited about this, it causes them to think and ask lots of questions, which is good. I think I tweeted that it was a triumph of human ingenuity, which I think it's not a triumph in the sense of changing the forefront of physics.

but the fact that people could do it and were willing to do it and thought they could do it and devoted years of time to doing it and it worked is it just amazing as a it's a big step forward in the thrometry yeah as someone as a theorist who works on a paper that sometimes you know sometimes they take months or years but usually you can do it in a few months and it's compared to the time the dedication that's required i always find that amazing yeah i couldn't do that myself i think it would be it's not the the way the way i work and going back to right to Ryland Hoyle, we mentioned earlier. Hoyle loved debates, and Ra got genuinely upset and didn't enjoy debate.

But there's an excuse, I think, and that Fred Hoy, if one theory was shot down, he'd think of another one the next day. But Martin Rihler spent years building instruments. Oh, I see. And people who've done that, they've got to feel it's going to discover something important. Yes, well, you can't, if you don't feel that, you wouldn't spend the time for that. That's right. That's right. And it's true to some extent for theorists who've worked for 20.

The string theorist, if you work for 20 years on, you have to feel that it's going to, it's got to be right, whether it is or not. The hallmark of a true scientist, of course, is being willing to throw, even if you spent 20 years being willing to throw it out when the experiment is agreed with, that's harder. But because in string theory, will they know it's wrong? No, I don't. I think it may be a case when we need AI. Yeah. Because it's just like the AI that can play games. It might be able to do the mathematics.

Oh, yeah. And tell us if a string theory is right. And if it spews out the right mass for the proton at the end. then you have confidence in the theory. I've often talked with my friend Frank Wilczek, who, you know, when I was, you're even writing about him in your new book. But we've agreed that many people are afraid of AI,

but one of the things that I find quite exciting is that it'd be interesting to see how it does physics, not just what it can teach us, but whether what AI thinks is important, the questions, you know, those things. And so it's fascinating to... I think that'll be what humans can do, but it'll be able to work through

these. And just like already they can test for drugs by simulating lots of chemicals and high TTC superconductors and things like that. Well, it'll be, I mean, of course, what's interesting about it at least right now, much of AI, is it's a black box. So it can play Go better than a goal player, but you don't know how. That's right. It just does it. And so

would we worry some, I guess, if you had an AI trying to solve these problems and it's spewed out 42 and to tell you why. Well, that's right. And that's, I guess that's possible. You know, that's possible. They could, you know, and they could, it's possible that you would never be able to fathom why, even say string theory or whatever it is. There could be no explanation in terms of that we could understand directly that it might say, yes, this is an accurate theory and this is the prediction. But I can't explain to you how I've done it.

No, you'd have to be able to understand how it did it. Yeah, well, in hopes we would. But it may, we may have always said, well, it just works. But I don't know. It'll be interesting to see how that sort of thing transpired. Well, you'd have to gain confidence in doing lots of things right, which you could check before you... Well, and, you know, interestingly, much of, I mean, one of the hopes of AI are some people is that quantum computing will potentially revolutionize what computers might be able to do. and Feynman, of course, was interested in quantum computing precisely, well, one of the reasons

he said he was, was because then computers would be, if you wish to call it that way, their thought process would be directly dependent on quantum mechanics, and therefore they may understand quantum mechanics better than us and might be able to explain it to him. Right. Yeah, which is, which I found very, since he, since quantum mechanics was pretty good to him, I found, I thought that was pretty interesting. Now, one of the things that are pressed as me, when we communicate relatively often by email. And it seems to me you read virtually everything. And I'm wondering whether that is always a case,

whether you always read voraciously from the time of a young man. But I'm always impressed that whatever I know it's happening, whether it's popular books or the media, you seem to be aware of it. Well, I'm aware. I don't necessarily read it at all. But I suppose I'm addicted to newsprints. so I read newspapers and...

Do you read, you read hard copies more than online? Never online. Really? Yeah, except when I'm traveling. But online and I look at the archive of astronomy papers every morning. There you go. So I read the abstracts, but I don't print out very many times you read. No, no, but that's very good that you dedicate and read.

But again, for listeners, all physics papers and astronomy papers... Even though I wouldn't say I spend more than 25% of my time on astronomy now. But it's nicely... So all physics... It's a wonderful thing that now it's changed the way science has done. Astronomy and cosmology and physics papers all appear, even before they appear in journals, appear online in something called the archive. And people who like to keep, therefore it allows you in a way that was not possible to

before to keep in touch with what's at the forefront. And actually, it's changed the sociology of science a little bit. It used to be when I was young and I was at Harvard, you used to get preprints. That's right. And you'd get preprints before anyone else. Yes. And it gave you a big leg up if you wanted to do work. That's right.

But now if you're in India, you get them at the same time. Which is wonderful. It's democratized science in a really important way. Oh, I'm glad you agree with me that. I think journals are on the way out, I think. Yeah, absolutely. I often, I found... Books are not, I don't think.

Yeah, I hope not. I just worry that people can't read things longer than a tweet anymore. And, but I don't know if you've ever done this, but I found journals are so anachronistic for me that I've had papers on the archive that when I submit them a journal and I find a particularly contentious referee who doesn't agree, I sometimes just said,

I don't care, I'll just leave you on the archive because it's there and it's lots of people refer to it and it's really archival which is really all journals are now in any case. But I don't know if you've ever done that.

I agree with that. I think the only case where you need refereeing obviously is if the publication is misleading. Yeah. If it's trivial, then it won't waste anyone's time. Yeah, yeah. So trivial.

papers. Yeah. You can read in the archive. But if it's something which can play, is based on wrong data, or something which is pretentious and might waste lots of time of some research duties in India or something trying to understand it, it's not worth it. Then I think for protection of those people, there should be refereeing. Yeah.

Of very difficult pretentious papers. Okay. Well, I know. I absolutely agree. And I've often even said in journals, when I was at Harvard, one of my colleagues was an editor of a journal. And he said, if he had his preference, he would publish everything he got along with the referees report beside us. And then you could read both and decide what you, and it'd be an interesting way of doing things. Yeah. Let me ask you something else. You read in only,

you only read in print, not on the computer, at least in the newspapers. Well, I mean, in the news. The newspapers, yeah. Well, I look at the BBC website, but I enjoy my newspapers. Yeah, no, me, me too. But it's interesting, because I wonder if that's a property of our age, well, whether, for example, I remember kind of a phase transition from me. When I first started writing scientific papers or anything, I could only write them if I wrote them down by hand on a piece of paper first and then then typed them if I had typed them myself on a computer. Now I could never do that. I can only write on the computer and I can't. Have you? Have you? I've made that transition too, yes. Okay, because there's some people who haven't. So I went. Now, speaking about

whether we're dinosaurs, as long as we go into that, there's a controversy. There's a controversy one, a quote-unquote controversy one hears about in cosmology, having to do with what's called the Hubble constant, the expansion rate of the universe. And many people seem to think that some radical new physics is required because the rate of which the universe is expanding by different measurements is somewhat different. And those measurements measure the expansion rate of the universe at different times. And within the statistical accuracy of those experiments, they differ and they're in disagreement. And some people say, well, that's, that requires a profound change in cosmology.

I'm old enough to remember when this expansion rate was measured in some units to be 100 plus or minus five, and other people would measure it to be 50 plus or minus five, and that meant they both couldn't be right. And not surprisingly, it came out to be sort of in the middle. Do you think it's gotten a lot of press, this potential controversy. Do you think it's, where do you fall on this? Well, if you asked me to bet, I'd bet it would be reconciled. Yeah, okay, good, we agree.

But obviously, I hope not, because if there was something fundamentally new, and of course you know there are very explanations of some little phase transition in space or something like that, that would be very exciting. But I think if you asked me to bet, I would speak about this just this week. And I would bet that probably there will be some recommendations. Well, that's one bet we both be on the same side of it. Because after all, I think the point is there's a lot of, I mean, there's a long history in astronomy. And as you point out, we can't do experiments.

we can only do observations, which means your subject, not only they are difficult to do, but you're subject to things you can't control. You can't twist the knobs in an observation. And therefore, what are called systematic uncertainties, namely things that you might not anticipate that might be biases in the experiment or in what you're observing that you can't control. And the history, there's a long history. If history is any guide, there's a long history of people seeing problems that went away

because we realized that things were just a little more complicated than the thought. That's right, yes. and indeed many false observations have been similar to theorists, which you've come up for new ideas. But exactly, the false observations have driven people sometimes the right fiction. I remember when I was a young assistant professor at Yale, an astronomer, Gus Omler, who was a distinguished astronomy colleague of mine, argued at the time, based on what he saw,

and this was probably in the early mid-80s, that astronomy would conspire so we could never measure the fundamental constants. There would always be some systematic concerns. go we'll never measure the expansion rate, we'll never measure it. And it's so amazing to see 30 years later how it's not just a factor two, but measured to five decimal places. That's right. It's just, to me, that is, I guess I was, I never would have, I really never had confidence that we

would be able to do cosmology, the precision we can do it now, even, even though I was pursuing it at the time. Well, it's much better data, of course, and also computers. And I think the microwave background data and, uh, and, You know, the funny curve with all the wiggles, which is due to oscillations. It's wonderful that we can observe those things on the sky with high precision and matched into a theory. And that theory, if you calculate forward, predicts, roughly speaking, the galaxies and the cluster in the Vs today. It really is amazing.

That's a huge triumph. I think that that in particular should be, when the history of this period in science is written, up there with plate tectonics and the genome. Yeah, I agree. I mean, this is a big, not just an astronomer, but in this. whole of science. Yeah, it's really remarkable that one can start more or less from first principles and produce a picture that looks, you know, of something that one people might think is complex, but the structure in the universe that we see that is remarkably similar that we see. It's just, it really is a triumph. And they're getting together observations made of when the

universe was tens of minus four, its present age, with what you observed today. You're combining them together. It's a triumph, but at the same time, I think it's worth pointing out something you said earlier. Because you hoped the Hubble constant, I mean, it would be nice if these measurements say that there's something fundamentally wrong with theory. I think many people don't understand that scientists like you and me are all scientists, really hope that we're wrong ultimately. Because then there's work left to do that it's much more exciting if an experiment disproves some fundamental assumptions because it really means that we have to go a new direction. Well, that's right, or something unexpected. like if there were big circles on the sky and like her background.

It's exciting. Absolutely. Well, I often tell people, and they don't believe me, that I do, you know, physics and cosmology because it's easier than, say, biology or it's certainly easier than the social sciences. And I want to make a segue now because your career has said you have many aspects. And both institutionally and personally, you've moved beyond. As you point out, you spend less than 25% of your time now on, on, uh, on, uh, on

knowledge and astrophysics. And in your career, you've had, yeah, besides being the Astronomer Royale and the Master Trinity College, president of the Royal Society, involved now in the Center for Existial Risk, and a Lord in the House of Lords in England, and therefore been progressively more involved in the nature of science and society far more generally. And you've been writing about that much more. And so is that a recent development of your life that you've been driven towards that. Have you always sort of had that fundamental interest? Well, I've always hoped for that, but I've been lucky than I thought I would be in having the opportunities. I mean, I've always been engaged with politics and going back to anti-nuclear

campaigns in 1960s and all that. And I went to Pugwash Conference in 1980s and indeed the first existential risks I started to worry about were, of course, the nuclear threats during the Cold War, which of course were far greater than any. people realized at the time. And still, I think, far greater than many people realized today. Well, except there are a few of weapons around. A few, but 5,000 can still do almost as much harm as $50,000. That's right. But then I had the chance to get involved in the science policy, et cetera, and more general. And so, and I've been very lucky in this. And that has indeed led me to write and talk quite a lot about these general themes and about the way science is going and about, you know,

big long-term issues like climate and environmental extinction and all that. I want to talk about a lot of those things. And it's interesting you say that because young people often ask, how can I have a trajectory like yours, you know, writing or speaking or being involved in these issues, speaking out. And what I tell them, and if I look at your life, I'd say exactly the same thing. The best thing you can do if you're a talented young scientist is do science. And then the more recognition or the more significant your contributions of science are, the more the more opportunities you'll have, if you're interested in those issues, to have an impact. The broader the effect will be, too. Do you find that? I mean, if you...

I think that's true, because, I mean, I'm not very good at any of the other things, and I've only been given the advantages because I'd established a reputation in my science. Yeah. Because one must exploit that, because we're all used to scientists who sound off about things they know nothing about in a dogmatic way. In a dogmatic way. I don't do that. Well, I think that, and we all have to worry about that for everyone. And scientists are, there's a fundamental difference in science and scientists, and we have to remember that. That scientists are human. And I think that that is, well, the question I would ask you, do scientists who have achieved some prominence have a responsibility, do you think, to speak out or at least making an effort to have an impact or not?

I mean, on science policy, on the public, etc. Well, I think if their work has a direct relevance to policy or welfare, and they should, they have an obligation to tell those in authority and ensure that if they've discovered something, that it is benignly applied and we minimize the risk of the downsides if it has those. And, of course, the atomic scientist of World War II, they were prime exemplars because they thought they were in the right, thing at the time. But when they returned to civilian life, they felt they had obligation to

try and harness the powers they'd helped unleash. And so those great men, we both were fortunate to know in the later years, you know, rockblatt, beta, and piles, people like that. They, I think, set an example, which now needs to be followed by scientists in other areas, climate and environment, certainly biologists. Yeah, exactly. I think, yeah, the scientific community in some sense has an obligation to advise on issues, as you say, that are relevant to policy. And we're both involved in the Bolton atomic scientists. I was very proud to chair it for a while and in the tradition that the atomic sciences, Sophenheimer and Einstein had created. But I think that at the same time, I think what's implicit in what you say is that if you're, it's not,

the other thing that worries me is that often when young people are writing grant proposals, they have to have to have an educational component or a social component to what they're, when in fact there may be none. And so by creating sort of artificial need for people to do something that they're not interested in, I don't think it's very productive. I think scientists who are interested obviously should use that opportunity in the soapbox that they may get. But it's not an necessity.

But if a scientist just wants to do science, to me that's, that's absolutely fine. Right. And I think, well, obviously, it's good if they do something educational, because in a democracy, it's important that everyone has a feel for science. Because lots of the issues, they have to address, be it on energy, environment. I would argue every single issue of politics. There's nothing that doesn't, and that does worry me.

We need a scientifically literate populist at some sense. If they're going to choose in a democracy, democracy won't work without an informed electorate and they need to be enforced. But we shouldn't moan too much. It's just as bad if they don't know the history of their country. Of course. Oh, yeah, yeah. What I mean is they should be literate.

So then literate means what literate used to mean, it seems to me, in the turn of the end of the 19th century, where you'd be able to have some general appreciation, you know, even then it's changed. But then a literate individual would have to have some cocktail party knowledge of what was going on in science. Now you could be proud to have none in some sense. You'd say, well, that just doesn't interest me. I think it's a shame. So I think everyone needs to take part in education.

But as far as public stances, then I agree it should be only those who are good at it. But I think there is a point that is important, which is that the scientists who I know, I guess you know, who've been political advisors have often felt rather frustrated. Yes. Because politicians have an agenda where there are urgent issues and issues which are local and to get them to worry about something like climate change, which is long term and which will affect people in Africa more than their own constituents, that's a big cell. And I think the only way in which one can get them to engage with these issues is if they know the voters are behind them. Exactly.

And that's why those charismatic figures who can influence the public are so important. And Carl Sagan was a prime example in our field. And I quote two recent examples where this has happened and doesn't have to be a scientist. I mean, I think the Pope's encyclical on climate change and the environments in mid-2015. That made a huge difference to the forgy consensus at the Paris conference because he got a standing ovation at the UN and he's got a billion followers in Latin America, Africa and East Asia. and that had a big effect. And the politicians, if they know that the public is behind them, will do this.

And a more recent parochial example in the UK, there's been a proposal by a fairly nondescript minister to legislate against non-reusible plastics, drinking stores and things like that, motivated by the concern of plastics in the ocean. And what's motivated that is the BBC Blue Planet programs fronted by our seconder Pope David Attenborough, and showing the stomachs of fish with this in,

and the albatross were turning from wandering and coughing up the plastics. That's an iconic image like the polar bear on the melting ice flow. And I think our British politicians would not have invested political capital in this legislation, had it not been for knowing that millions of people had watched this. started to care about it. So I think it's those sorts of people, Attenborough and Sagan and a few people now who are very important. Well, I think, I mean, one thing that's absolutely clear, and one of the reasons

why I sort of got involved in the bolt and it's atomic, and it's Tuesday clock, is that politicians don't lead, they follow. That if, I mean, every major change I know of, including when I was growing up at the Vietnam War, was driven not by the last people to be involved. were the politicians. You had to have a social movement at some level. And in terms of climate change, I've been wondering, and nuclear weapons, what will be the Sputnik moment, what will be the moment where there's enough public, how can we get a public because if the politicians know, and it doesn't matter whether it's a democracy or not, if leaders know that the vast majority of their population feels a certain way, it has an impact,

and they get led by that. Well, and of course, anti-slavery, civil rights in the U.S., gay rights and all these things. They've started with a few people, then they've gained public support, and the politicians take it up. And there's a nice quote from Margaret Mead, saying it takes only a few to determine of people to change the world.

Indeed, nothing else ever has. Yeah, yeah. And that's very true. I think it's true. And I hope it gives hope to those, because these problems seem so grand that most people say, what on earth can I do about it?

But we can all be evangelists in our own, in our way, we all have effect our children, or their schools, if you go to church, the churches, et cetera. Let me, interesting, you brought up the Pope, because I do want to, I have a, we differ a little bit there, but I want to, you know, in your most recent book, The Future of Humanity, you talk about a lot of issues,

both problems and perspectives and hopes, both from the nature of humanity and the nature of science, which was enjoyable for me to read. Obviously, I share many of your opinions. It covers a lot of things, and those who don't like it, we'll call it a dog's breakfast. Those who like it more was there's a smorgasbord. Okay. Well, I guess I would call the smorgasbord based on what I saw. And maybe partly because most of the things I agree with there.

So maybe that's always a fact. But there are things I kind of, well, I want to ask you questions about. One of the issues you point out that is understated is the issue of population and the concern about a world where there could be between, say, 9 and 20 billion people, depending upon how it goes in Africa and the ability to have a world where everyone has at least the opportunities to live a life that we like to think we should, we have. I mean, without excesses of, you know, big cars and wasting energy, but a quality of living that is comparable to what we have now and whether it's possible on this planet to have 20 billion people that have a quality of living.

And it also, when it comes to climate change and pollution, the major negative feature in terms of climate change pollution is the number of people because the more people. And that, and that, rarely gets discussed, I think for a number of reasons, partly for the fact that at least one religion is not in favor of population control at all. And so I wanted to point out, you point out rightly in the book that, you know, wheat requires 1,500 kilograms of water, whereas beef, it requires at least 10 times that much. Are you a vegetarian? I'm only, I don't want to put you in spot. No, I mean, I always choose fish if there's a choice. Yeah, no, and I don't mean to put it that way, Because I know the same things as you and I'm not either.

But I do think that vegetarian is going to catch on. Two things by 2050, I predict firmly. One is more vegetarians, and there's more euthanasia. Oh, okay. But if you get on to that later, perhaps. Okay, we'll get to that later. I know that when I told him I moved to Oregon, you said one of the great things, but you might want to come visit because one of the great things about Oregon is it has assisted suicides.

That's right. So it's the last place I want to go to. The last place in that sense. Okay, yes. But now let me hit you on the, the thing where I think I disagree with you a little bit. You know, I'm often disappointed in the Pope. In fact, rarely am I not.

Although, I will say, and to be fair, we should point out that you're on the, what is it, the board of the Pontifical Academy of Sciences. By the way, to me, the Pontifical Academy of Sciences is an oxymor on that term. Anyway, I don't view the church as the bastion of science. I never have. But although they support it, and there's no doubt, and I visited because of you. The only time I've ever been there is a conference that you, I think, helped organize the long-term future of the universe. And I got to the pleasure of being there.

And thank you for that. And there's these events they have people of all faiths and none. Oh, okay. No, no, exactly. It's not as if they try and impose that. But at the same time, in this, the Pope's encyclical on this subject, where you, it's in the chapter of book on population that you actually discuss it. The whole point is that the church is opposed to the very thing that's never. necessary, which is contraception, family planning, and in some sense the ability of women in the

third world to protect themselves against AIDS. And I think so at this, I just found it hollow in the sense of- I disapprove of that. But so, I mean, I think you're just, so you like, I know that you're more generous in your, in your assessment of things. I thought that how can you be taken seriously as someone who's promoting a huge problem as a problem when you, when you're, when you're, when your whole church is invested in promoting that problem. And I have less sympathy. Well, I mean, going back to the population, I think the population is leveling off.

I mean, there's a special problem in Africa. Well, there is, but that's exactly where the church is working so hard to counter what's necessary to be done in Africa, more than any other group. Along with your President Bush. Or President Bush and Trump, you mean, yeah. No, oh, absolutely. I'm not, but, but, but, and I can despise them. But, but they are the, they are, in my opinion,

That very church, which is directly responsible for most of the negative things that are related to population in Africa, along with misplaced political leaders. There's no doubt. Many of whom base their ridiculous notions on religious grounds, right, on the notion that somehow either contraception is a sin or homosexuality is a sin and people deserve to die. And so those misplaced notions, which are, frankly, religious ones, are holding us back from progress. Well, they're not all misplaced, and I would say they do more, the church does more good than harm. I know, that's where we disagree. And we've written, and you've written about that. And you've won the temple the prize. I don't have any religious beliefs.

Yes, I know. But I'd be sad to see the church getting weaker, and I'm happy to participate, just. as lots of Jews who are atheists like their candle on Friday night because they want to preserve the traditions. And I'd be very sad if our cathedrals fell down, if there was no church music and all that, and if I couldn't be buried in the churchyard. So you're, I was reading about this.

You don't call yourself a cultural Christian. A lot of us called, a lot of my, I'm Jewish background. A lot of my friends will call themselves cultural Jews in the sense that they're atheists, but they like the tradition. And it's the tradition of the church you like. Yes, I do. I grew up in that. And if I was in Iran, I'd probably go to the mosque in the same spirit.

And I don't mean to put you on the spot here, but it's a conversation that people should be willing to have in respectful way. But you'd be sad if the church became weaker. But of course, the Church of England has become weaker. Yes, I'm sad. And you're sad about that. You'd be happier if the church had more control in education than it had. I mean, you know, one of the quotes that I just learned since I came here is the Archbishop of Canterbury, He said that educating children is like engraving in stone. And that just, when I read that, I just thought, it terrified me to read that because, of course, the education that he's talking about is not one I want children to have.

Well, I don't think our bishop would actually feel that. I think he's very well-remises about these matters. But I think the point about religion is they emphasize what we have in common when so much divides us in modern society. And Because I tend to think that religion Is always in us versus this thing I mean as a

Maybe because I brought up It was brought up in a Jewish tradition And I learned and what I learned there Is that somehow we were better We were always oppressed but we're always better No but fundamentalism Obviously is an evil And I think we need all the allies

To be Sure Against it Against it And I would see the Pope and the aspect of can't be As us allies And that's why I'm against people who rubbish them Yeah, yeah. Well, I don't think we need them on our side.

I think it's, but I think we both agree that nothing is sacred in that sense. And therefore, we should be allowed to disagree with the Pope. Of course. And point out when we think that the Pope could do. Just as I was recently talking to someone here about, someone who disappoints me all the time is the Dalai Lama, although on a scale of things, he's sort of kindler and gentler. Right, yes. So I think it's, but I think it's very important to point out that nothing is about. of sort of a...

No, that's right. But the point is, I can't understand how people can actually believe religious dogmas. Yeah. Okay? But clearly some people do. And you can't dismiss them all as naive or stupid. No, they're not... So there's something that we're missing if we don't appreciate this.

And I think we should not attack them. No, no. But maybe we should... I don't think we should ever attack people. I think ideas are perfectly reasonable to attack. And that, I think, is... And so I think it's important to attack ideas that are wrong. because people, beliefs of influence actions.

And, for example, the belief that homosexuality is a sin influences actions as influence actions. My country and your country that I think are fundamentally irrational. Do you agree? Well, I don't think you use the word rational in the context of morality. Because there's no rationality. This is a sort of fallacy to believe that you can get ethics and reason. And most people who say that, they believe in a naive early 19th century usitarianism.

I know. We've talked about the difference you can't get ought from is. But I do think it's irrational. Let me give you the reason why. If empirical evidence suggests something, and your actions are disagree with empirical evidence, I would argue that's irrational. And the empirical evidence about homosexuality is that in most species,

there's long-term homosexuality, that there's no evidence of immoralism. morality among homosexuals. So, you have to, science can inform your morality. And if the evidence all points towards one thing and you do something else, I would call that a rational. Or it certainly would be uninformed. And do you agree with that?

Well, I mean, I share your views about homosexuality, of course. But I think in principle, I mean, if you tell you, it's, you can't get an art from an is. Well, you can't get an art, but you can go a long way. You can say an art that it's, you can say an art that it's, you can. disagrees with observation. Like, you know, I would like to fly. It might be an ought, you know,

something I wish for, and maybe I can believe I can. But the is is if I step out the window, I'm going to fall. And so I think, I think if our aughts are not informed by what is, then I think we can make, you know, knowing what is may not determine what we should do. That I agree with you completely. And I have to say my discussions with you over time have impacted on my own thinking in that regard. really moderated them and informed them.

But nevertheless, so it's sort of necessary but not sufficient, I'd say. So that even if you know what is, reasonable people can disagree about what the implications of that are. But if your ought is not correlated to what is, I think we can say unambiguously that your ought is wrong. You don't agree? Well, I'm not sure because I think you can't assume there's a progress in ethics necessarily.

No, no progress. But look, I mean, the point is, let's take homosexuality. Once again, it's not unnatural. We know that sheep, 10% of sheep make long-term, you know, homosexual, monogamous, homosexual. That's irrelevant to the ethics. Well, it's irrelevant to the ethics. But if people say it's unnatural and goes against nature, that is wrong. And therefore, if that's what motivates their ought, we can say, sorry, that's not a judge.

I agree with it. If that's their reason, yes. Okay, good. As long as we agree about that. I mean, there are lots of reasons that are subtle. But if you, or if you say, you know, the Earth is 6,000 years old and that determines, you know, what I'm going to do. We can say, sorry, no, no, I don't, I may respect you as an individual, but I don't respect that notion. And I refuse to give it equal time or, you know, and I, yeah, so I think it's really, it's very important to ridicule ideas from Jonathan Swift on.

I think, I think that ridicule is a useful tool. But, you know, I mean, but you're just a kind of a gentler person than me. I know that. I mean, we need to have allies against fundamentalism, and that's why I think we should not criticize the mainstream churches. And also, if you were a teacher and you had some Muslim kids in your class, if you say they can't have their God and Darwin, then they choose their God and be lost to science. That's one reason why I think Richard Dawkins does harm rather than good. I know, and we've had that discussion. I think we can encourage kids to question. I think it's all right to encourage kids to question their faith without telling them they're wrong. But you're absolutely right.

I think if we say, you know, what you think is you can't believe what you believe. Well, we should never do that anyway. I mean, I think we should, as educators, that would be a shame. So I would not want to crusade against religion. That's what I'm saying. I know, I know. And I think it's important that there's many different views of it. But as I say, you know, I don't want to belabor this.

But I'm more willing to criticize influential religious figures. Well, you've traipsed around the world with Richard Dawkins doing just this. Well, I have. I have. And usually trying to trapes against scientific ignorance, which is what I'm really talking about. Parozy atheism. No, I never promoted. I've asked people to think about it.

And the so-called New Atheists. Well, I don't know what new atheists are. Well, the book just comes out at Hard Covers, which is a sort of conversation by those four people 10 years ago, now dignified with hard covers. Yeah. It's sort of a undergraduate-level conversation by, by, you know, It would be small-time Bertrand Russell's saying what other people said 50, 100 years ago. I've said for a long time. And it's hard to beat Bertrand Russell.

I agree. Every time I think of saying something new and I look back, I've discovered it in one way or another, that he said it better and more deeply. That's true. But on the other hand, I'm surprised you use the word new, what do you mean by new atheists? I mean. Well, they use the word. I don't use the word. I don't mean, atheism has been around for a long.

It's certainly the phrase that they use themselves. Yeah, well, I, wow. It's on the cover of the book. really? That's really a shame. Because, yeah, I don't understand what means. Just like I don't understand what Millet's an atheist means. I just, you know, as I say, it means it means I mean you throw pamphlets or books of people. I don't know what it means. Well, you know, I want to, so I want to focus on you now. We've been, we've been having this discussion and giving me my ideas, but let's conclude by talking a little bit about, I was fascinated to read

a number of the statements you made, which were interesting to me or presented things in a, in a different way than I'd been thinking, which is always wonderful. You called yourself a technological optimist and a political pessimist, which maybe explain that. Yes. Well, of course, we wouldn't live the lives we do today, had it not been for the technology of the 19th century and the 20th century, and we have the capacity to provide a decent life for the 7.5 billion people now. And I think, incidentally, probably for the 9 billion, maybe by the...

mid-sensaries, although I agree that we should hope the population goes down rather than up after that time. But I think we can hope that technology can improve us. But I think there's a big gap between the way the world could be and the way it is. And that gap, I fear, is widening. Because I think that the power of science is going up, but I think the problems of governance, and avoiding the downsides and avoiding the mavericks who can produce damage that cascades even globally, that's going to cause big problems. And I think that that gap between the way the world could be ideally and the way it is,

is probably going to widen a lot. It's already wide because I think the reason I'm dubious about claims of ethical progress is that if you look back to the 14th century, life was pretty miserable. But there wasn't much they could have done to improve it. Whereas now life is indeed far better for everyone in terms of life expectancy, education, health and all the rest of it than it was then.

But the gap between the way it actually is with still a billion people in abject poverty in the world and 2,000 people whose money could cure that poverty at the other extreme. This surely belies any claim of ethical progress collectively. So interesting. So your attitude towards, say, Steve Pinker's argument about the Enlightenment making, that the world is better now than it's ever been,

is moderated at least by this notion that, well, it may be better, but it should have been, it could be. Well, that's right. I mean, clearly, I think it's a great book, and he's got all these figures about life expectancy, and all that. And he and Hans Rosling and all that. They deploy this very well

and there's no denying what they say. But I think there are two things that he misses out. One is that I think he's lulled into underestimating these new emergent threats, which are rare but would be catastrophic if they haven't even once. And that's what I worry a lot about in my book. And also I think that there is, a big gap between the way things are and the way they could be,

even though there's no gain saying that things are better for most people in the world than they were in the 14th century, even the 19th century. No, when I was reading your book, I think that was the thing that it made me think the most, was your statement that, you know, despite the highly, you know, even the fact that our conceptual horizons about the universe have improved so much. Yes, yes. You know, from thousands of years to billions of years. and in every way our understanding of ourselves and the universe is in Greece.

Despite that, there's a bigger gulf between the way things are. And I thought, wow, I think that's a fascinating claim. Interestingly, less disposition to think long term, because I think of the cathedral builders who built a cathedral which they knew would not be finished in their lifetime. And although their horizons in space and time are limited, that seems paradoxical. The reason is not paradoxical, actually, is that in the medieval period,

they may have thought the world would only last a thousand years, but they thought the lives of their children and their grandchildren would be similar to theirs. So they thought their grandchildren would be there to appreciate the Finnish cathedral. Whereas now we have these huge horizons in astronomy and geology and all the rest. But we can't predict what the life would be like for the next or next but one generation. Because Czech technology has changed so fast. so fast. And so I think that's the

excuses, as it were, for some failures to plan long term. If we don't quite know what it'll be like then. Well, we can be pretty certain that predictions we make would be wrong. Yeah, that's right. In medieval times, they were despite all the uncertainties,

the long-term trends were slow, they thought. Yeah, no, I found that as I always get from you when I discuss with you, new insights that, and that a new insight for me that I think is incredibly profound. And it's a problem. It's at the time when we most need long-term thinking, we're most discouraged from having long-term thinking. By the rapid changes. Yeah, that's a real issue. And I guess it's happening in England too, but in the United States, we've had that problem for a long time in that it's very, science gets

harder and you need projects take longer. Large science becomes big science. And in the United States, there's a yearly approval process so that, you know, for example, in the case of my field, there was a big collider being built in the United States. Three presidents had approved it, but all you needed was one, so it'd been going for 15 years,

like you needed one Congress, and there's always a cycle of economics where there'll be a downturn. And the easiest thing to get rid of is a large-scale science project. That's esoteric because it just, you can say that. And so I am worried about our ability to address as a society

large problems without the public outcry that, yes, we need to spend 20 years and a lot of money solving them. Yes. Of course, that project was a bit different of space, wasn't it? Yeah, the public did care about space. Yeah, they cared about it. Whereas they didn't care about the accelerator. Well, you know, and I think it was a lesson.

I don't know, in my field, what scientists learned the lesson of not courting the public first. Partly because of the Manhattan Project, we'd sort of been guaranteed money in this field and felt we didn't have to explain why we did stuff. huge clouds at that time. Yeah, and we didn't feel I had to explain why. The bucket was open and suddenly I saw a new appreciation for people like me and others, but people who the field felt it was necessary to actually explain why we wanted to do these things to the public, which should be there all along because the public should understand why the money is being spent

and should say, well, you know, it's worth doing. And one of my favorite lines of any scientist, I've written about it many times is Robert Wilson. Did you know Robert Wilson? Oh, that civilization. Yeah, yeah. Whether the Fermi collider would help the defense of the nation, he said, no, but it'll help keep the nation worth defending, which I thought was a...

Well, let's go to something dismal and then maybe optimistic at the end. Yeah. There are, you are concerned about a lot of issues, I mean, obviously climate change population or two, but there are, and we both spent our time, both in your existential risk and future humanity efforts and mine to the Bolton of Atomic scientists, is folk looking at emerging existential risks.

And there are some. And you want to just elaborate what keeps you up at night? Yes, I'm not sure they're existential, but I do worry very much about holding the fabric of society together when it's so easily disrupted by just a few people, empowered by technology. We see it's already with cyber attacks, and it'll be possible by error by design to reduce a pathogen

and cause some biological hazards. which could spread extensively. So I think that it's going to be very hard to control this. And obviously these new technologies need to be regulated. And there are, as we know, attempts to regulate genetics and all that, on ethical and prudential grounds. But even if we have these regulations and they're agreed, then enforcing them is going to be as hard as enforcing the drug laws

or the tax laws globally. We know how hopeless that's been. And I think the point is that it's not like nuclear facilities where they're large, a cosmicuous and you can molliser them and inspect them, etc. It's very, very hard. And this is going to lead to, I think, a growing tension between liberty, security and privacy. And I suspect it's privacy is going to have to give.

And, of course, the younger generation don't mind about that anyway. Yeah, it seems it's already been given. That's right. That's right. We're going to have to give up that. But still, I think we do need to worry because these sort of long-tail risks, which are unlikely but could be catastrophic, are growing. And if we think back, we both know Jared Dahmer's book, collapse. We had five collapses, but none of them were global, whereas now, I think, something bad in one continent is going to spread because of the global. financial system and all the rest of it. No one escaped to be set back globally. And this is something which does make me worried about the bumpy

ride we may have through this century with these technologies. And there's going to be arms race between the defenders and the attackers for cyber effects and all that. But the question is it may be a problem. And also I think

society is getting more fragile. I mean, again, about to the 14th century, half the population of some towns died black death, but the other half went on fatalistically. If we had some sort of pandemic now, then I think before the number of casualties reached 1%, there'd be social breakdown because that would overwhelm the capacity of hospitals and people clamour for attention, et cetera. And similarly, if there was some breakdown in the electric power grid in the eastern United

States where the lights going out is the least of your problems. Then again, you get social breakdown within a few days. In fact, actually, you know, you mentioned something in your book, and it's funny because I've talked to, well, I was actually in a film of a friend of mine, Werner Herzog, called Lo and Behold. Yes. But we are susceptible in ways we weren't before, for example, to get back to a field of ours and yours in particular, but if there's a large-scale solar flare that produces a...

That's right. It could... 500 years ago, it wouldn't have been noticed. No, that's right. But now it could produce an electrical surge that would knock out the internet, knock out, knock, and that, Werner's argued, would produce such social disruption, he thinks it would be, it would be one of the more serious things. I don't know if it is, but if we couldn't, if we couldn't, more and more things tied to the internet, you're referred from your refrigerator to, you know, to getting out of your house. Yes, yes. We are much more susceptible to those kind of problems.

That's right. problems. Now, and for me, in my pessimistic mode, which I, which is, as I say, often there, I tend to think that, I don't take a defeatist attitude, but I think when you talk about these things that may be possible, and you point out that we can't, it's hard to enforce, as you say, with nuclear weapons, there's a big infrastructure, but if you can rewrite DNA in your, in your basement or in your garage, you know, it's a much harder enforce. Or in a small, scale lab, I tend to think we have to think that except for those things which violate universal human morays, and I think there are some, that we have to accept that sort of what's possible

is going to happen. And what we need to do is think about how to deal with it when it does, that fortune favors the prepared money. Which is why I think it's so important that people like you frame these questions, even if they're difficult to listen to and hard to think about, If we don't think about them, then we do it much more of our peril than... Well, that's right. So, I mean, I hope that by thinking about them, we can at least cut the risk by one part in 10,000 and thereby have more than earned our keep for doing it. Well, I think you've more than earned your keep in many ways.

And you've certainly more than earned your keep. Thank you for this discussion. And as always, I told you, I'm always inclined by you. Thank you so much. No, great. We've gone on for hours. We haven't talked about space. Yeah, we haven't even talked about space.

Well, I hope we'll have a chance to do this again. Hope so, yes. Okay, you take care. Yeah, good. The Origins podcast is produced by Lawrence Krauss, Nancy Dahl, Amelia Huggins, John and Don Edwards, and Rob Zeps, directed and edited by Gus and Luke Holwurda, audio by Thomas Amison,

web design by Redmond Media Lab, animation by Tomahawk Visual Effects, and music by Riccolus. To see the full video of this podcast, as well as other bonus content, visit us at patreon.com slash origins podcast.