Professor Brian Greene: "Science Has Been Wrong About Reality" (String Theory & God)

1. 0:00 – 2:42

   Intro

   1. BGBrian Greene0:00

      And I can't convince you that we're not in the matrix. Why? We could be. Is this table real? Am I really here? Am I a simulation sitting inside some computer? Or maybe there's a kit on 29th century Earth, and they happen to allow you and I to exist sitting at this table. And here's a big assumption. Can you create a computer program that has consciousness? Nobody knows the answer to that. But I've spoken to some of today's AI researchers who think that ChatGPT is conscious. And in the back of my mind, I do think it's possible.

   2. SBSteven Bartlett0:30

      But if we considered robots to be conscious, would they then get rights?

   3. BGBrian Greene0:34

      I think that's something we should think about now, actually.

   4. SBSteven Bartlett0:36

      Professor Brian Greene, what is the ultimate question that you're seeking to answer?

   5. BGBrian Greene0:40

      We find ourselves thrust on this planet, and we're trying to figure out why we're here. Is there some ultimate purpose? We're a little dot on planet Earth, and you begin to see our sun, one of many stars within the galaxy. You can look at our Milky Way galaxy within the setting of the entire universe.

   6. SBSteven Bartlett1:00

      And what's beyond?

   7. BGBrian Greene1:01

      Well, if the universe is infinite, if you go sufficiently far out into space, you're virtually guaranteed to find a copy of yourself out there.

   8. SBSteven Bartlett1:08

      There's a version out there of me that just loves wine.

   9. BGBrian Greene1:11

      [laughs] There you go.

   10. SBSteven Bartlett1:12

       So should I feel insignificant?

   11. BGBrian Greene1:14

       I would urge you not to, because fact that we can understand that we are so small, that's what gives us a sense of connection to something larger.

   12. SBSteven Bartlett1:23

       Do you think it could lead us to God?

   13. BGBrian Greene1:24

       If you mean the kind of God our forebears often have spoken, that feels to me very much a human creation. I will tell you why I'm skeptical of that. But another thing we should think about is the end of the Earth. Because if we go arbitrarily far into the future, the Earth is gonna spiral.

   14. SBSteven Bartlett1:41

       It's about to get scary.

   15. BGBrian Greene1:42

       Well, it's scary the whole way.

   16. SBSteven Bartlett1:48

       This is super interesting to me. My team give me this report to show me how many of you that watch this show subscribe, and some of you have told us, according to this, that you are unsubscribed from the channel randomly. So favor to ask all of you, please could you check right now if you've hit the subscribe button if you are a regular viewer of the show and you like what we do here. We're approaching quite a significant landmark on this show in terms of a subscriber number. So if there was one simple free thing that you could do to help us, my team, everyone here, to keep this show free, to keep it improving year over year and week over week, it is just to hit that subscribe button and to double-check if you've hit it. Only thing I'll ever ask of you. Do we have a deal? If you do it, I'll tell you what I'll do. I'll make sure every single week, every single month, we fight harder and harder and harder and harder to bring you the guests and conversations that you wanna hear. I've stayed true to that promise since the very beginning of The Diary of a CEO, and I will not let you down. Please help us. Really appreciate it. Let's get on with the show. [upbeat music]

2. 2:42 – 4:09

   The Big Question Science Is Trying to Answer

   1. SBSteven Bartlett2:43

      Professor Brian Greene, what is the ultimate question that you're seeking to answer?

   2. BGBrian Greene2:50

      The ultimate question I would say is what is the true nature of reality? We find ourselves thrust on this planet, and we look out, and we're trying to figure out why we're here, what it's made of. Is there some ultimate purpose, or is it just some interesting accident that allowed us to have self-awareness and ask these kinds of questions about the nature of the world? And I think that, to me, is the, the deepest kind of question that we humans can ask.

   3. SBSteven Bartlett3:21

      Do you feel like over the last 30 years of your career you've gotten closer to understanding the answer to that question?

   4. BGBrian Greene3:27

      Yes, but, you know, it's kind of like picking up grains of sand on a beach, right? You pick up more and more, and that, that pouch of sand gets heavier, so your understanding is, is deeper, it's weightier, but you look out, and there's just almost infinitely more grains of sand that are out there. We understand the world better than we once did, but does that really take us some significant way toward assessing the big, deep questions of, say, why is there something rather than nothing? Maybe that's the deepest question of all. By which I don't mean empty space. I mean nothing. Nothing at all.

3. 4:09 – 5:04

   How String Theory Could Explain Our Universe

   1. SBSteven Bartlett4:09

      Well, we'll, in this conversation, go in the pursuit of that answer. To tell people who you are and to let them understand the journey you've been on academically and through your career, where did you study? Where have you worked over the last couple of decades?

   2. BGBrian Greene4:22

      Yeah, sure. Well, I grew up in Manhattan right across from the Hayden Planetarium. I would wander the hallways of the planetarium and come upon a meteorite, and the universe was sort of my backyard because of that. And that really set me on a trajectory that I continued following when I went to college. I went to Harvard and studied mathematics and physics. Then from there it was to, uh, Oxford, where I got my doctorate, pursuing work in a field called string theory. And then through the academic ladder, Cornell and ultimately Columbia, where I've been a professor now for 30 some odd years, you know, director of the Center for Theoretical Physics at Columbia University.

4. 5:04 – 6:37

   How Could We Ever Prove String Theory Is Real?

   1. SBSteven Bartlett5:04

      If you were to explain string theory to me-

   2. BGBrian Greene5:06

      Yeah

   3. SBSteven Bartlett5:06

      ... like I was 12-

   4. BGBrian Greene5:07

      Yeah

   5. SBSteven Bartlett5:07

      ... how would you do it?

   6. BGBrian Greene5:08

      Yeah, I would simply say this: Your 12-year-old self probably knew that matter was made up of stuff called molecules that themselves are made up of atoms that are stuck together, and the, the atoms are made of smaller things. Electrons in orbit around a nucleus that has neutrons and protons, and neutrons and protons, they even have smaller particles, particles called quarks. The question is, is that the end of the story? Is it electrons and quarks and you're done? Everything is made up of them. Or might there be a finer level of structure inside the electron, inside the quark? You take a powerful microscope and you look deeply, would you see anything else? And the idea of string theory is, yeah, you would. Inside an electron or inside a quark, you'd see a little tiny vibrating filament, and the different vibrations of the string yield the different particles. So much like a string on a violin when it vibrates in one pattern, you hear it as a C or a, or an A sharp.

   7. SBSteven Bartlett6:09

      Mm-hmm.

   8. BGBrian Greene6:09

      The different vibrations of the strings in string theory, they don't produce different musical tones. They produce different particles. So a string vibrating one way, electron. A string vibrating another way, a quark. So matter at its most fundamental level, if you were to take a powerful microscope and look deeply inside of any piece of matter, you'd see all these little vibrating filaments, these vibrating strings. That's the idea of the theory.

5. 6:37 – 8:12

   What Makes the Strings in String Theory Vibrate?

   1. SBSteven Bartlett6:37

      So I have two questions come to mind when you say that, which is how do you know? And the second one is what if you zoomed in even further?

   2. BGBrian Greene6:43

      Yeah, good. Both good questions. How do we know? We don't. Everything I just said could be utter nonsense. I don't think it is, but the only way that you know if an idea in science is correct is you need to make predictions that you can go out and test, measure, and see whether you can confirm the ideas. We don't have the technology to look sufficiently deeply into matter to see the strings. We don't have the particle accelerators, the particle colliders with enough power to slam things together to access this finer level of structure that the theory's suggesting. So you might say then where do these ideas come from, right? Answer, mathematics. The power of mathematics is that it can take us to places that we can't yet go literally using equipment. When we look at the mathematics of quantum mechanics, the mathematics of general relativity, and we put that math inside the math of string theory, all of a sudden the equations work. They come together harmoniously, and we're like, whoa. The math of quantum mechanics, we're confident in that. We have predictions and observations. The math of general relativity, we're confident in that. It makes predictions we've confirmed through observations. Now we're willing to go where the math takes us, and the math takes us in this approach to these vibrating filaments.

   3. SBSteven Bartlett8:10

      These vibrating strings.

   4. BGBrian Greene8:11

      These vibrating strings.

6. 8:12 – 9:36

   Can String Theory Explain Why We’re Here?

   1. SBSteven Bartlett8:12

      So if you pass me this string here.

   2. BGBrian Greene8:13

      Yeah, sure.

   3. SBSteven Bartlett8:14

      So essentially if you zoom into every cell in my body-

   4. BGBrian Greene8:17

      Yeah

   5. SBSteven Bartlett8:18

      ... you will find that there's different shaped strings vibrating?

   6. BGBrian Greene8:21

      That's the prediction.

   7. SBSteven Bartlett8:22

      That's the prediction.

   8. BGBrian Greene8:23

      Correct.

   9. SBSteven Bartlett8:23

      And what is causing them to vibrate in a certain way?

   10. BGBrian Greene8:27

       Yeah.

   11. SBSteven Bartlett8:27

       Who's telling them?

   12. BGBrian Greene8:28

       Yeah, yeah. The idea is we recognize that the universe has energy. If you were to ask me where does the energy come from, nobody can answer that. That is the question of why there is something rather than nothing. The something is a fundamental currency called energy. If string theory is correct, then that energy manifests as these vibrational patterns of the strings themselves. If the theory's wrong, then the energy manifests through other things like motions of particles and the way in which spacetime warps and curves. But if string theory's correct, the energy of the universe is manifested into vibrational patterns of strings. Now, when you say, like, who mandates that that string vibrates in one pattern and that string vibrates in a different pattern? If we go back to the Big Bang, the energetic explosion that resulted in space expanding, the detailed way in which that happened ultimately dictates how this or that string vibrates in the aftermath of that rapid cosmological explosion.

7. 9:36 – 11:43

   What If We’re Living in a Simulation?

   1. SBSteven Bartlett9:36

      Does this string theory idea tell us anything about why we're here?

   2. BGBrian Greene9:42

      I would like to think that it does. It's very indirect, and we are aggregates of a huge number of particles, or if string theory is correct, of a huge number of strings. I mean, inside your body you've got something like a billion, billion, billion particles, and if string theory is correct, each of those particles is a vibrating filament. It is a gargantuan challenge to understand why those billion, billion, billion particles came together to yield you or me or somebody else. But again, that's a historical progression, and I think we understand the broad outlines of that narrative, that there was some initial event called the Big Bang that resulted in space expanding. The energy of that Big Bang ultimately transmuted into particles. Those particles were wafting through space. Gravity caused collections of those particles to clump together. Some of them clumped together into stars like our sun. Some of them clumped together into planets like our Earth. And on our Earth, some of those particles began to coalesce into more exotic and refined forms, giving rise to atoms, giving rise to molecules. And over the course of billions of years on our planet, those little molecules grew into more complex structures, ultimately giving first cells. And once you have a cell, cells divide, and they come together into larger multicellular aggregates that gave rise to the beginnings of life in the ocean, and those life forms evolve further until they can walk out of the ocean and begin to live on land, and they begin to stand upright. And after a billion more years, you and I are sitting here at this table. And so, yeah, there is a story. That's the brief version that takes us from the Big Bang to us on planet Earth.

8. 11:43 – 17:43

   How Can Physics Explain Human Emotions?

   1. SBSteven Bartlett11:43

      Is it theoretical that this is all just a... I was gonna say perception, but the other word might be a simulation of sorts. Theoretically, we don't even know if yesterday exists-

   2. BGBrian Greene11:53

      Yeah

   3. SBSteven Bartlett11:53

      ... or if it was just, we were just implanted with the memory of it. You know?

   4. BGBrian Greene11:56

      Absolutely right.

   5. SBSteven Bartlett11:57

      We're in this age of AI now, and I wondered if this insurgence of AI And how powerful it is. And if you imagine it on a sort of an exponential curve, has it made you question some of your like fundamental assumptions about that overarching question of why we're here?

   6. BGBrian Greene12:16

      Well, yeah. In fact, even before AI, we were tussling with the very notion that you mentioned, which is all we ever have access to is now, right? We can try to remember yesterday's now, but as you say, that's happening right now through patterns that are in my brain or yours that we think reflect something that happened yesterday or the day before, but that's a leap of faith, right? So there's a kind of, you know, skeptical nightmare scenario where we begin to question everything. You know, is this table real? Am I really here? Am I a simulation sitting inside some computer right now? Are we in the matrix right now? These are the kinds of things which you naturally can come to when you take a deeply skeptical attitude to the nature of reality. Bottom line is, I can't convince myself, and certainly I can't convince you, that we're not in the matrix. Why? We could be. It is logically consistent and sensible to imagine that you and I are sitting in some computer. Maybe it's not, you know, some dark dystopian computer the way it was in the matrix. Maybe there's a kid in, you know, twenty-ninth century Earth who's in his or her garage right now, and they came up with this wonderful computer program, and they're simulating historical episodes in the past, and they happen to allow you and I to exist sitting at this table. I don't know how to prove that that's not the case. What I can say is, if I'm willing to buy into that, everything falls apart. I can't trust any... I can't trust my reasoning. I can't even trust my thinking that it's logical to imagine that individual, because that individual may have implanted the false reasoning that it could be logical for us to be sitting here. What do I do at that point? And so as a scientist, what I say is, "I'm gonna allow that as a possibility, and then I'm gonna park it right over here." I allow it. I look at it every so often. I say, "That's scary, that possibility that we're in a simulation, but I'm not gonna let it overwhelm me because then I'll be stuck."

   7. SBSteven Bartlett14:34

      The simulation argument popularized by philosopher Nick Bostrom relies on probability.

   8. BGBrian Greene14:38

      Yeah.

   9. SBSteven Bartlett14:39

      Um, it essentially says that if an advanced civilization, which I would argue we're an advanced civilization, ever develops the technological capacity to run conscious, high-fidelity computer simulations of their ancestors, they will likely run millions of or billions of them. And because these simulated realities would vastly outnumber the single raw physical universe, any given conscious observer is statistically almost certainly living inside a software code rather than base reality.

   10. BGBrian Greene15:08

       The big assumption is, can you create a computer program that has self-awareness, that has consciousness? You know, nobody knows the answer to that. I've, I've spoken to some of today's AI researchers who think that ChatGPT is conscious, that, who think that Claude is conscious. Now, I lo- I, I talk to them and I'm respectful. That's the kind of person I am. But in the back of my mind, I'm like, "Are you kidding me? You really think that ChatGPT has feelings? That it thinks about its own existence and has anxieties?" I think it can simulate that, but regardless, I don't think today's technology is there. Is it possible that tomorrow's technology, broadly defined, a year, five years, a hundred years, really will yield self-aware, sentient artificial systems? Yeah. I do think it's possible. Now, not everybody agrees with that. I mean, no one knows, right? It's a logical possibility, but we don't know. Let us assume, following Nick Bostrom, that consciousness can be created in a mechanical box. If that's possible, then Nick simply says, "Look, our progeny in the future, they're gonna be fascinated with creating sentient systems. And so they're gonna create millions and billions and trillions of, of sentient systems in the box. And they're gonna get really elaborate and create a version where the sentient beings are led to think that they're on a planet. And in fact, they're gonna do it a thousand billion trillion different ways. Some are gonna be a planet like Earth. Some are gonna be on a planet like Mars. Some are gonna be a planet like around some star in the Andromeda galaxy. There are gonna be an enormous number of simulated beings, enormous number of universes that are simulated." So the question is, if we have one real universe, let's say this is real, and a gazillion artificial ones that are created in various laptop computers of the future, we're one of a billion trillion zillion instantiations of people who think that they're real. Now, one truly is real, the other are not real. So if you're just talking about odds, the odds are anybody who thinks they're real is not. The odds are anybody who's got a self-aware sense of the world is probably in a simulation.

9. 17:43 – 19:13

   Could Humans One Day Manufacture Emotions?

   1. SBSteven Bartlett17:43

      You used anxiety as a sort of, of a proxy for consciousness, almost like the be- being able to feel these things.

   2. BGBrian Greene17:48

      Yeah.

   3. SBSteven Bartlett17:48

      I guess the question then becomes like, what is, what is it? [chuckles] What is anxiety?

   4. BGBrian Greene17:52

      Yeah.

   5. SBSteven Bartlett17:52

      Is it an electrical signal going through from-

   6. BGBrian Greene17:54

      I do think it is. I think that love and hate and anxiety and jealousy and gratitude and grief and all human emotion is nothing but ... electrical impulses going through our brains. And an electrical impulse is just particles moving or strings moving along various connections. I think that is all that it is. Now, some people hear it and they're like, "Wow, that is a pretty bleak way of looking at life. We're these wondrous beings who can have all this emotion, right? The emotion captured by Shakespeare in the sonnets, right? The emotion captured by Beethoven in the Ninth Symphony. You can't reduce that to electrical signals in the brain." And I say, "Yeah, I, uh, you can. I really do think that you can." I don't think that diminishes the wonder of what we can feel and sense and articulate and express through the various ways that we have, be it through music or theater or art or literature or poetry. Yeah, I am as awestruck by our capacity to create as, as anybody else. But in the end, I think it all does reduce to electrical impulses going through this gray piece of meat in this bone cage that's sitting on

10. 19:13 – 20:44

    Would Knowing We’re in a Simulation Change Anything?

    1. BGBrian Greene19:13

       our shoulders.

    2. SBSteven Bartlett19:14

       And if you imagine any rate of improvement from today, presumably at some point in the future, our future ancest- our future progeny, you called them-

    3. BGBrian Greene19:21

       Yeah

    4. SBSteven Bartlett19:22

       ... would be able to create that.

    5. BGBrian Greene19:24

       Why not? That's my view. I don't think there's something special about the brain as a substrate. I think as long as you have the same electrical impulses, if they're housed in silicon inside a metallic box, I don't think that makes them fundamentally different than what's happening inside of our heads. Now, philosophers argue this, you know, psychologists argue this. They say, "No, no, no, no. It's not just the brain, it's the brain, it's the connection to the body. It's the tactile sense of the world. It's the olfactory sense of the world. It's the visual sen- it's only when you put it all together that you get the full experience of what it means to be self-aware, a self-aware human being." And my view is, well, maybe that's true, but if so, give the artificial version tactile sense and olfactory sense and visual sense. We will have the capacity to do this. At that point, I just don't see a fundamental difference between the artificial version and, shall we call it the organic. And so, yeah, I think there's a really interesting argument to be made that simulations will outnumber real worlds, and therefore there's a chance that right now we are in one of those simulated worlds.

11. 20:44 – 21:19

    Could Humans and AI Eventually Merge?

    1. SBSteven Bartlett20:45

       Does it change anything, even if that's true?

    2. BGBrian Greene20:48

       No, I don't think it does, and I think that's the beauty. If I'm in a simulation, I'm gonna live out my life in this simulation to the fullest.

    3. SBSteven Bartlett20:56

       Yeah. [chuckles]

    4. BGBrian Greene20:56

       Now, I'd like to think that as a physicist, what I do, what my colleagues do, is try to figure out the laws of the universe writ large. But if we're in a simulation and all we're doing is figuring out the laws that the 15-year-old futuristic kid decided to impose on this artificial world, hey, that's not a bad way to spend your time too.

12. 21:19 – 25:17

    Could Humans Ever Achieve Immortality?

    1. SBSteven Bartlett21:19

       On this subject of AI, do you-- I mean, a lot of people that have sat here, people like Geoffrey Hinton, have told me that it's quite inconceivable that when there is a more intelligent life form on this planet, i.e. AI, which is accelerating in its intelligence towards super intelligence and AGI and all these terms that these smart people use, um, it's inconceivable that we will remain in control.

    2. BGBrian Greene21:39

       Yeah.

    3. SBSteven Bartlett21:40

       Logically, that kind of also stacks up.

    4. BGBrian Greene21:41

       It does, but, but I think there are alternatives. We tend to speak very much at the extremes, right? Humans are in control. AI is in control. AI wipes us out for reasons that might be benign or might be dystopian. It seems to me that what will likely happen is something more in the middle, which is we are going to work with artificial systems. We're doing it right now, and look how quickly we have acclimated to a world that would be unthinkable in 2021. There are many examples now, but there's a beautiful one that's on my mind. An 80-year-old mathematical conjecture, I think it's called the Jacobian conjecture, was solved very recently by a mathematician using AI. I see us blending with AI, not necessarily that we have implants, but maybe we will, but there will not be as sharp a distinction between the biological intelligence and the artificial intelligence. And that to me, if that ultimately yields a new life form that no longer, mm, can be called human, that may be the way things evolve. And so evolution is something that is inherent to how we got here. Why would we think that this moment in the evolutionary progression was the end of it all? We weren't gonna continue to evolve, and maybe the continuation of our evolution is in partnership with the artificial intelligence systems that we ourselves create.

    5. SBSteven Bartlett23:34

       That we give birth to.

    6. BGBrian Greene23:35

       Yeah. It's us, right? It's our creation. You know, it's not an alien. We haven't been taken over. And so, yeah, I think that is a, a real possible way that this story plays out.

    7. SBSteven Bartlett23:48

       How do you feel about it?

    8. BGBrian Greene23:50

       I am fine with it. You know, I think that we tend to become very attached-

    9. SBSteven Bartlett23:58

       Mm

    10. BGBrian Greene23:58

        ... to the way things are, and we gain a sense of the way things are is the way it will always be. I think that's a natural way that we humans have lived our lives. Why? Because the timescales for change in our past have been relatively slow.

    11. SBSteven Bartlett24:19

        Right.

    12. BGBrian Greene24:19

        Right? We live, what, 30, 40, 50, call it 80 years, 100 years, whatever, but the timescales for change were typically much larger than that, the timescales for political change and the timescales for technological change much larger. So as a species, we've grown accustomed to the thought that, yeah, what we see is how it will always be. But of course, as we look back through history, we can see the changes. And so we're uncomfortable with change because we're unused to living through that kind of change at the kind of speed that we are and will continue to encounter. But I think we just have to get with it. Now, look, I don't want AI system to wipe us out, don't get me wrong, but I think if we recognize that change is happening, will happening, we can embrace it in a way that will have an outcome that will be acceptable, that will in fact be wonderful in the things that it will allow us to do.

13. 25:17 – 27:19

    How Knowing We’ll Die Shapes Every Decision We Make

    1. SBSteven Bartlett25:17

       I, I'm quite curious, you talked about AI being able to solve that complex math problem.

    2. BGBrian Greene25:21

       Yeah.

    3. SBSteven Bartlett25:21

       I'm wondering if with accelerating ever more intelligent AI, there's a bunch of other things within physics that you think might become possible-

    4. BGBrian Greene25:30

       Oh, yeah

    5. SBSteven Bartlett25:30

       ... in the near term. I mean, one of them I was thinking about, we can talk about some of the others that I have in my mind, but, um, and any others that you think are interesting, but one of them is us being able to live forever.

    6. BGBrian Greene25:38

       Yeah. Yeah, yeah.

    7. SBSteven Bartlett25:39

       Do you think we're gonna be able to live forever?

    8. BGBrian Greene25:41

       Yeah, that would be a, that would be a good one. I don't think that death is inevitable in the sense that death can be thought of as the increase in entropy, the increase in disorder in a physical system, and when the entropy gets too large, the system can't function the way it once did, and that's really what we call death, right? That's really what it means. And so in principle, we can imagine harnessing some of the processes that have caused the degradation in the human body that have naturally resulted in us typically not living more than 100 or 120 years. I mean, people like, you know, David Sinclair, who I've spoken to about things like this, yeah, you know, I think we can forestall the kinds of degradation. Now, if you're talking to me, I think on timescales that are so much longer than a human life. I think about timescales that speak to the entire timeframe of the cosmos from beginning to the closest that science can take us to the very end. And on those scales, I don't think that we'll be able to forestall death. But please note, the timescales I'm talking about are ludicrous compared to any timescale that we are familiar with. 100 more years, 200 more years, maybe 500 more years, I don't think anybody can really say for sure. I do think that is within the possible range of what science and medicine will ultimately be able to accomplish.

14. 27:19 – 30:44

    Why Are We Here? The Optimistic and Pessimistic Answers

    1. BGBrian Greene27:19

       And I will say though, you know, I, I read a book, I don't know, it was about in my 20s, called The Denial of Death by Ernest Becker. He was a social psychologist, I guess sociologist, who believed strongly that so much of what we do in our lives is driven by our awareness of our own mortality. And as I began to think more and more about that, it made more and more s- sense to me, which had a dual effect on me. Very interesting framework to think about your life within the context of recognizing its finite nature. But the flip side of that is you're constantly thinking about your own death [laughs] you know, which, you know, is a, a curious way to go about your life. But I don't think the denial of death, that human motivation, would go away if we lived 200 years or 300 or 500. Yeah, we'd have longer lifespans. We'd be able to do more things. But, you know, if we live to 500, you know, as we approach 450, 475, we'll be thinking the exact same thoughts that we think now as we approach 70 or 80. It'll be no different. And so from a fundamental perspective, yeah, I would choose to live longer, but I don't think it changes anything fundamentally.

    2. SBSteven Bartlett28:37

       Uh, I find it quite interesting. I was actually writing a, a letter about this, sort of an, an article to myself really about this yesterday, about this idea of long-termism and how when you just change the time horizon of something, the decisions you make today are different.

    3. BGBrian Greene28:49

       Yeah.

    4. SBSteven Bartlett28:49

       And a simple way of explaining this through the context of, like, business would be if I told you to build a business and I gave you one year-

    5. BGBrian Greene28:56

       Yeah

    6. SBSteven Bartlett28:56

       ... and unlimited resources, but you had to build it as big as you could, you would take certain shortcuts-

    7. BGBrian Greene29:01

       Yeah

    8. SBSteven Bartlett29:01

       ... and you would m- maybe not think about the foundations. But if I gave you t- 20 years, you'd really make great foundations, and then, you know, you'd-

    9. BGBrian Greene29:08

       Yeah

    10. SBSteven Bartlett29:08

        ... build up from there. And I think about the same in our lives because we do have this sort of, sort of inbuilt time horizon, okay, I'm gonna live maybe 80 years, and then I'm 30 and then 40 and then kids, and then I start to g- you know, change. And, um, maybe at some deeper level we are making a certain set of decisions based on that time horizon that we wouldn't make otherwise.

    11. BGBrian Greene29:25

        Yeah. I mean, when I was 20 or 30, you know, even though I had this mindset that was inculcated by reading Becker's book, there was a certain sense of an infinite horizon that somehow was infusing your decisions, you know, to write a book. Well, that's like a four-year undertaking. But, you know, when you're 30, you're like, "Yeah, sure. Yeah, yeah, yeah. I'm gonna do that." Now, I'm gonna choose those books with a certain [laughs] kind of care, right?

    12. SBSteven Bartlett29:56

        Yeah. [laughs]

    13. BGBrian Greene29:56

        Y- you know, there's a different kind of mindset that, that is brought to bear. So I certainly agree that the time horizon has a profound impact on the moment-to-moment choices. But the pattern that we humans go through from birth, you know, to adolescence, uh, adulthood, middle age, to ultimately old age if we're lucky, and then, you know, we disappear, that pattern will persist regardless of what the ultimate scale of it is, whether it's eighty years-

    14. SBSteven Bartlett30:26

        Mm-hmm

    15. BGBrian Greene30:26

        ... or eight hundred years. I think that we would go through a very similar kind of rhythmic variation in how we approach the world. If we were immortal, that would change a lot. But I don't see immortality in our future.

15. 30:44 – 33:53

    How Did Gods and Religions First Emerge?

    1. SBSteven Bartlett30:44

       What is the sort of l- l- the least inspiring possibility of the sort of answer to the big question of why we're here? And then I'll ask you the, the-

    2. BGBrian Greene30:51

       Yeah

    3. SBSteven Bartlett30:51

       ... most optimistic possibility.

    4. BGBrian Greene30:54

       Yeah, I think the least inspiring would be if, what if in the end of the day, it's all just an accident? There is no deep explanation for why the world is the way it is. There's no deep explanation for why there's something rather than nothing. And if that's the truth, I'm on board. But it wouldn't feel as enriching as it might be, if I can now jump to the other side [chuckles] of your question, you know, if there is a true fundamental answer to the question of why there is anything at all, and I recognize that that answer dovetails with everything else that we've been developing. That answer ultimately yields quantum mechanics, and yields the general theory of relativity, and maybe even yields string theory. That would feel deeply satisfying. Why did our brain evolve? So we could get the next meal. So we could get shelter. So we could get a mate and have progeny, allowing our genetic material to propagate into our descendants, right? This is what the brain was meant to do, and yet this brain can do so much more than that. It can figure [chuckles] out the equations of physics. That's, that's a miracle right there. And so the deep gratification would come from this brain being able to figure out some stuff, and then it dovetails with the deep explanation for why there's anything at all, giving us a coherent narrative from the beginning until today, and perhaps on into the far future. Yeah.

    5. SBSteven Bartlett32:28

       Do you think it's gonna happen? Do you think we're gonna answer that question?

    6. BGBrian Greene32:30

       You know, I, I don't know. Nobody does. I think all vectors are pointing in a direction that suggests that there are real explanations, that it's not just happenstance. There are these particles we mentioned before called electrons. Here it is, my spinning electron, right? And so when an electron spins, it gives rise to a little magnetic field, sort of like a trillionth of the strength of the magnetic field of a magnet on your refrigerator. We can use the math of quantum mechanics to predict the strength of that magnetic field, and we can do it, and it comes out two point ba-ba-ba, fifteen decimal places long. We can do the math. We then can measure the magnetic field, and it agrees digit by digit by [chuckles] digit by digit by digit with what we calculate. Our prediction is borne out by our observations to fifteen decimal places. I mean, that's breathtaking. We should not have been able to [chuckles] do that in some sense, to understand the world that deeply with a brain that really was focused upon, you know, getting the bison. And so the fact that we can do that suggests to me that there are these deep patterns in the world that will ultimately stitch together into a coherent story.

16. 33:53 – 37:01

    What’s the Most Compelling Case for a God?

    1. SBSteven Bartlett33:53

       Do you think it could lead us to God?

    2. BGBrian Greene33:56

       Well, it depend-

    3. SBSteven Bartlett33:56

       Or religion?

    4. BGBrian Greene33:57

       Yeah, it depends what you mean by God. You know, if you mean the kind of God that our forebears often have spoken of, and people today as well, a, a kind of anthropomorphized being, you know, sitting on the throne in some heavenly place, I suspect not. Uh, that feels to me very much a human creation, and a wondrous human creation. I'm not of the mindset as some of my science colleagues are, that religion is an enemy of science and needs to be wiped... It can be, but anything can be an enemy of anything else. It depends how you use it. I see religion not as a structure that tries to explain the world in terms of its workings. I see it as a structure that tries to quell our anxiety, our existential anxiety. Where did religions come from? They came from our forebears recognizing that they would die. So, you know, our forebears had these elaborate rituals of burying their dead. There are these wonderful caves, um, in various parts of the world that have been excavated, where the grave goods, as they call it, involving, you know, animal teeth stitched together care- It would take a single individual years to create the grave goods that are buried with an individual. Why would they spend the time on that? Well, they were imagining that death is not the end, that that individual needed those grave goods for their next journey into the afterlife. And why were they thinking about that? Because it's too terrifying to imagine that death is truly the end. And so from that, you can see the glimmers of a religious sensibility emerging, where we want to have something that suggests that death is not the end. So we invent these beautiful structures called religions. And I say that even from a personal standpoint. I don't believe in any of the traditional religious practices, right? I'm Jewish. I was raised sort of Jewish, more culturally than religiously. Do I pray on occasion? Yeah, I do. Do I believe that I'm praying to an actual god? I do not But the act of going through the kind of ritual that our ancestors did and giving yourself over momentarily to something that you imagine as being more powerful, I think it's deeply in our nature.

    5. SBSteven Bartlett36:33

       So who are you praying to?

    6. BGBrian Greene36:34

       I am praying to the universe, if I have to give a word to it, recognizing that this prayer is going to fall on deaf ears because there's nothing else out there to hear it, but it makes me feel better. And so there's a part of my mind that's willing to allow the scientific understanding to have its place, but the irrational human side to have its place, too.

17. 37:01 – 40:32

    How Can We Comprehend Billions of Years?

    1. SBSteven Bartlett37:02

       What is the, the most compelling argument or idea or experience you've ever encountered for a god, like the ones we read about in the Bibles?

    2. BGBrian Greene37:10

       Very little. Very little. You know, somebody died in the operating room, and they were able to, uh, leave their body and see things that they could not possibly have seen, and then they reported back when they were revived, and people were like, "Oh, you must have died and left your body. That's the on-" No. No, no, no. The human brain has this wonderful imaginative capacity to see things inside of its head that it doesn't literally see. That's what we can do. And so I've never seen a single example where I couldn't feel that I could give a logical explanation which was more compelling than the supernatural explanation.

    3. SBSteven Bartlett37:47

       What about the Big Bang, then?

    4. BGBrian Greene37:48

       Good. So the Big Bang is a question of how it got started.

    5. SBSteven Bartlett37:54

       Yeah.

    6. BGBrian Greene37:55

       And over time, we have been able to push our understanding ever further back. So in about 19, uh, call it '29 or so, Edwin Hubble, who was a great astronomer, noticed through powerful observations through the telescope at Mount Wilson Observatory in California that the distant galaxies all seemed to be moving away. Interesting. Others, Georges Lemaître, who was a Belgian priest, as it turns out, who also knew Einstein's general relativity, said, "Well, look, if all the galaxies are moving away, just wind that cosmic film backwards. Back in time, they must have been closer and closer and closer together. Way back in the beginning, they must have all been on top of each other. And then everything running the film forward must have swelled outward in a Big Bang-like explosion."

    7. SBSteven Bartlett38:47

       Let there be light.

    8. BGBrian Greene38:47

       Let there be light, yeah. And so starting in 1929, we began to have a scientific account of how it is that the universe may have been billions of years ago. And in our era, other scientists took the story even further, suggesting that there was an earlier era when the universe was just infused with a kind of uniform energy. You could say, where did the energy come? I don't know. But if it was infused with this uniform energy, they showed that the math required that the universe underwent this rapid swelling, the Big Bang. And so era by era by era, my point is we can push our understanding ever more deeply, trying to get at cosmic origins. We have not been able to push back to time zero itself, but because we're able to push our understanding further back and make predictions about, for instance, what's known as the cosmic microwave background radiation. This is heat that we can observe today that was left over from the Big Bang. Big Bang was very hot. The universe has cooled ever since for 13.8 billion years. We can detect the residual heat from the Big Bang. And so this gives me confidence that we're inching toward the answer to the question that you asked. Now, will we require God at some point? By which I mean, will we say, "We've gone as far as we can." Will we have to invoke something else? I can't say no, but I don't see any reason at this point to envision that we won't be able to push all the way to a full understanding.

18. 40:32 – 43:08

    Does Our Place in the Universe Make Us Insignificant?

    1. SBSteven Bartlett40:33

       Most of us don't really understand, um, I guess how scale-

    2. BGBrian Greene40:39

       Yeah

    3. SBSteven Bartlett40:39

       ... and time have a relationship.

    4. BGBrian Greene40:42

       Yeah.

    5. SBSteven Bartlett40:42

       Which means that, you know, I've been alive for 33 years now, and it feels like a long time.

    6. BGBrian Greene40:45

       Yeah.

    7. SBSteven Bartlett40:46

       But I'm presuming the further and further you zoom out and the sort of the bigger, the wider the scale gets, time is experienced differently. So actually, I could have been here for a second in a toddler's universe who's created the simulation.

    8. BGBrian Greene40:59

       Yes, all of this is possible when simulations are part of the story. But if you put that to the side and just look at our universe, yeah, the timescales even there are shocking. I mean, Carl Sagan used an analogy. He said, "Look, if you want to understand the timescales of the universe from the beginning until today," which is billions of years, like 13.8 billion years, he said, "Here's one way to do it. Imagine that all of cosmic history from the beginning until today, you compress it down to one year."

    9. SBSteven Bartlett41:31

       Right.

    10. BGBrian Greene41:33

        Now, in that scheme, that means each day is about 40,000 years. But you can then put all of the milestone moments in the evolution of the universe on the calendar. So imagine you have the Big Bang as January 1st. Then the Milky Way galaxy forms, like, something around, you know, March 15th or something like that, and the Sun and the Earth form sometime, you know, in May, you know. And then the first, you know, life on Earth is sometime in December, like December 2nd. And then, you know, the first modern humans, they appear, like, on New Year's Eve, right?

    11. SBSteven Bartlett42:10

        Really?

    12. BGBrian Greene42:10

        And then all of civilization takes place in the last 10 seconds, right? So at, like, 11:55, you know, it's the, it's the rise of the Buddha. 11:56, the fall of Rome. 11:58, the Renaissance. 11:59, like one second to the stroke of midnight, you get modern science. So, like, modern science is, like, one second in this cosmic calendar. And so that helps you get a feel for the timescales that are involved when you're talking cosmologically. 'Cause you're right, 33 years in a lifetime, you know, I'm, I'm gonna posit you're gonna live to 99, let's say. That's one-third of your life. You know, that's, that's not small, it's not big, but, you know, it's a significant part of it. On cosmic terms [laughs] , 33 years? It's zero. It doesn't register. That's how tiny it is on the scales that we're talking about cosmologically.

19. 43:08 – 47:19

    How Big Is the Observable Universe, Really?

    1. SBSteven Bartlett43:09

       So should I feel insignificant?

    2. BGBrian Greene43:11

       You can. I would urge you not to. One of the reactions to all this certainly can be, look, we're a little tiny speck in space, right? I mean, you can give the same kind of context for space itself, right? Because we're on a planet around the Sun. The Sun is one star of 100 billion others or so in the Milky Way galaxy.

    3. SBSteven Bartlett43:35

       Have you got a-

    4. BGBrian Greene43:35

       Yeah, I think there's a, a little version of this thing here if we can get this guy to go on. Right, yeah, so if you sort of start, like, here, right? Here we are [laughs] in the studio, right? And if here we then begin to pull out to planet Earth, like, we're a little dot on planet Earth. And then if you pull out from there, this is Earth within the solar system. You begin to see how tiny we look even on the scale of the solar system. But of course, here you can pull out further, and you begin to see our Sun, one of many stars within the galaxy. You only see a few here, but, you know, there are 100 billion stars in our galaxy. And then you can go even further than that. You can look at our Milky Way galaxy within the setting of the entire universe that has at least 100 billion other galaxies. So we, as a little tiny speck around our star, our star is one of 100 billion stars in a galaxy that's one of 100 billion galaxies. That can certainly make you feel small in space. The beauty, though, is that our minds can reach out to the edge of the cosmos. The fact that we can understand that we are so small is what gives us heft. That's what gives us a sense of connection to something larger. I imagine that fish don't realize that they're, like, in one ocean of many oceans on the Earth that's one planet. I, I don't think, maybe I'm wrong, and maybe the fish [laughs] are like, "Ah, yeah, yeah, yeah."

    5. SBSteven Bartlett45:09

       [laughs]

    6. BGBrian Greene45:09

       You know. But, but assuming that the fish don't know that, they don't know that they're insignificant. They don't even really think in those terms, per se. But the fact that we can do that, the fact that we can realize how insignificant we are when you talk about the expanse of space, you realize that there are other measures of significance. And one measure of significance is your ability to understand your own predicament. And the fact that we can do that is what, to me, is wondrous.

    7. SBSteven Bartlett45:39

       How do we know we're not just, that whole universe there isn't just a, we're just a, a, a microbe in the, in the gut of a f- of a fish? [laughs]

    8. BGBrian Greene45:46

       Yeah, we, we could. And again, that's much like the simulation argument. But let me give an example on here that helps give you a sense of why we believe this stuff. This here is the cosmic microwave background radiation. This is the heat left over from the beginning. Now, it's color-coded. The different colors correspond to different temperatures in space. This is a picture of space with a device that measures the temperature at each location and assigns it a color.

    9. SBSteven Bartlett46:18

       How much of space, or just a segment?

    10. BGBrian Greene46:20

        This is a segment of the observable universe.

    11. SBSteven Bartlett46:22

        Okay.

    12. BGBrian Greene46:22

        The segment that we can see. Now, space can be much larger than things that we can see. That's absolutely the case. But my point is these tiny color variations correspond to tiny temperature differences. We can use mathematics to predict the pattern of the temperature variations, and what we predict matches this image to incredible precision. And so the fact that we can do a calculation right at this table with a piece of paper, a pencil, and a computer and generate an image that agrees with what we see, we say, look, yeah, we can be skeptical. Maybe we don't have the full answer, but that agreement gives us confidence that we've got something in the direction of truth. And that, to me, is what gives us something that counteracts the feeling of insignificance.

20. 47:19 – 48:16

    What Exists Beyond the Observable Universe?

    1. SBSteven Bartlett47:19

       And on that, if you just pull that up again.

    2. BGBrian Greene47:20

       Yeah, sure.

    3. SBSteven Bartlett47:20

       So h- this is the observable universe.

    4. BGBrian Greene47:22

       Yeah.

    5. SBSteven Bartlett47:22

       Which is, I mean, how big is that?

    6. BGBrian Greene47:24

       The universe is about 13.8 billion years old, so you'd think that the univ- the distance we could see would be about 13.8 billion light-years, the distance light can travel in one year. We can actually see a little bit further, more like 45 billion light-years. So you can think about this as here we are, we look out billions of light-years that way, billions of light-years that way, billions of light-years in every direction, and this is like a big sphere that surrounds us, and we're measuring its temperature, the temperature of space, the photons that have traveled to us from about 300,000 years after the beginning. So this picture is a snapshot, in essence, of what the universe was like a mere moment, in cosmological terms, 300,000 years after the beginning. That is an amazing picture.

21. 48:16 – 52:05

    Why Are Humans So Obsessed With Aliens?

    1. SBSteven Bartlett48:17

       And what's beyond?

    2. BGBrian Greene48:19

       I don't know. I don't have any reason to suspect that reality radically changes just beyond the place that we can see. I think it's incredibly unlikely that the world is so consistent with our scientific understanding for it to all be a ruse.

    3. SBSteven Bartlett48:39

       So is it infinite?

    4. BGBrian Greene48:41

       It could be. And if it is infinite, there are some really weird things, if what we have been talking about isn't weird enough, right? You know, if the universe is infinite, if you go sufficiently far out into space, you're virtually guaranteed to find a copy of yourself out there and a copy of the Earth out there and a copy of our galaxy out there. It's virtually impossible to imagine a universe that goes on infinitely far and doesn't repeat. You know, in fact, I see a prop here. I can sort of tell you why, right? So here's a deck of cards, right? And I think it's a new deck. Yeah. So everything is in order, right? It's all perfectly ordered like that. Now, if I was to take this deck of cards and I start to shuffle it, right? So, you know, I'm not a particularly good shuffler, but, you know, you get the basic idea. You know, I keep shuffling, and of course, the order changes every time, right? So if I now-- You know, I'm not a great shuffler, so there are probably still, you know, some things that are still, you know, in numerical order, but it's more mixed up than it was before. And I can keep on doing this. Now, sooner or later, if I continue to shuffle these cards over and over and over and over and over and over again, sooner or later it will get back to the completely ordered arrangement. Why? Because there aren't enough different arrangements to go around, right? That idea applies in the universe in the following way. In any region of space, there are particles. Those particles can be arranged in a variety of different ways. Here they're arranged so that you and I are sitting at this table, and we got the cameras and everything. This is just a particle arrangement. There are only a finite number of arrangements of particles in any given region of space. This you can establish from the laws of quantum physics. So if you go out far enough in space, region by region by region, the particles will have different arrangements, but they have to repeat, much like the order of the cards has to repeat. So there has to be a place out there. In fact, if it goes on infinitely far, if you imagine that I shuffle these cards infinitely many times, I'll get that nice ordered arrangement infinitely many times, too. Similarly, there are infinitely many copies of you, of me, of everything we're familiar with out there in the cosmos. And so if the universe is infinite, it kind of challenges a little bit our sense of self, right? Like, what does it mean to be who you are if there are other versions of you having the exact same thoughts, they had the same childhood, they had the same history? Because again, that's just an arrangement of particles over time, and it has to repeat.

    5. SBSteven Bartlett51:24

       There's a version out there of me that just loves wine.

    6. BGBrian Greene51:27

       [laughs] There you go, right? In fact, it's even easier, I should say, for the particle arrangement to almost but not quite exactly replicate what we're familiar with, which would mean there's a universe out there in which you and I are interchanged, or you grew up in New York City and I grew up some-- you know, because those are, again, almost replications. You got the Earth, you got the Sun, but the detailed particle arrangement is close to but not identical to what we are used to. So yeah, an infinite universe brings in some fairly strange ideas.

22. 52:05 – 54:46

    Ads

    1. SBSteven Bartlett52:06

       But even in the observable universe, I mean, this transitions nicely to the subject of aliens, which people are-

    2. BGBrian Greene52:10

       Yeah

    3. SBSteven Bartlett52:11

       ... very obsessed about. I guess there's two questions here, which is why do we care so much, I guess philosophically, about aliens?

    4. BGBrian Greene52:17

       You know, I think we, at least in this country and elsewhere, too, we love the idea of conspiracy. We love the idea that the deep state is hiding things from us. And by we I don't mean me. I sort of mean the zeitgeist, you know, loves the idea of this Area 51. You know, so I think there's a, a, a, a desire for there to be more than what's apparent on the surface. And wouldn't it be exciting if, you know, we've long known that there are these aliens, they've visited us, and it's been kept under wraps. That's like the deep conspiracy. That feeds that hunger for there to be something that is being hidden from us. Now, I think the other reason is we're deeply lonely as a species. Sure, we've got people around, but, you know, I think this sense, the desire for a god I don't think is that much different from the desire for there to be other life out there. It's the desire to be part of something bigger. Now, if you ask me, do I think there are actually other life forms out there, I'd like to think of it in two ways. One, yeah, I think it's hard to imagine that we're the only life. I mean, the more we look, the more we find the organic molecules necessary for life. You know, amino acids, nucleic acids. You know, the, the raw material seems to not be too hard to come by in the cosmos. So to imagine that there's other, you know, bacterial life or viruses out there, that seems to me a reasonable working hypothesis. But if you then say, "But what about intelligent life?" And by intelligent life, let's just call us intelligent. It's debatable, but let's just say that. You know, that is a harder question. I mean, even on our planet, right, it was an asteroid 65 million years ago that wiped out the dinosaurs and in that way opened up the evolutionary pathway by which we came to dominate in the way that we do. Without that, it could still be the dinosaurs are grazing around on various plant life and other life forms on the surface of this Earth. And without that kind of accident on some other world, maybe intelligent life is rare or even so rare that we're the only example. So I don't consider that an absurd perspective as well, that there is life, but there may not be any intelligence beyond us.

23. 54:46 – 56:46

    What Is the Meaning of Life?

    1. SBSteven Bartlett54:47

       Much of the reason most people haven't posted content or built their personal brand is because it's hard and it's time-consuming, and we're all very, very busy. And if you've never posted something before, there's so many factors in your psychology that stop you wanting to post. What people will think of you. Am I doing this right? Is the thing I'm saying absolutely stupid? All of these result in paralysis, which means you don't post and your feed goes bare. I'm an investor in a company called Stan Store, which you've probably heard me talk about, and what they've been building is this new tool called Stanley that uses AI, looks at your feed, looks at your tone of voice, looks at your history, looks at your best performing posts, and tells you what you should post, makes those posts for you. You can also just use it for inspiration. And sometimes what we need when we're thinking about doing a post for our social media channels is inspiration. Building an audience has fundamentally changed my life, and I think it could change yours too. So I'm inviting you to give this new tool a shot and let me know what you think. All you have to do is search coach.stan.store now to get started. Whenever I talk to new founders, they all carry the same belief, that the biggest threat to their small business is having a bad product. It's not. The biggest threat they face is hiring the wrong person for their small team because bad hires put the handbrake on growth and rapidly infect company culture. And I get it. When you're starting out, you need A players to grow your company, but you don't have 40 spare hours to spend sifting through interviews, so you hire fast to fill the seat, but this ends up costing you even more in the long term. What any small business actually needs is a reliable and efficient way to find the right talent without stalling momentum. That's where our long-term sponsor LinkedIn and LinkedIn Hiring Pro can help you. It streamlines the entire hiring process from drafting a job description to shortlisting candidates and conducting AI-powered interviews for initial screenings. Nearly 60% of hirers who've used this tool have found a candidate to interview within a week. Hire right the first time around, and get started by posting your first job for free at linkedin.com/DOAC. That's linkedin.com/DOAC and terms and conditions apply.

24. 56:46 – 1:01:01

    Is Free Will Actually Real?

    1. SBSteven Bartlett56:46

       If one of your children came to you and said, "Dad, um, what is, what is the meaning then of this life? If we're, we're alone in this universe, it's a gazillion miles away from anything interesting in the cosmic spectrum of things. What is the meaning of all of this, Dad?"

    2. BGBrian Greene56:59

       Yeah. Well, they do ask. [chuckles]

    3. SBSteven Bartlett57:01

       Oh, they do?

    4. BGBrian Greene57:01

       You know, un- unfortunately or fortunately, because I spend a lot of time thinking about this stuff and writing about it, it's sort of in, in the familial zeitgeist at home, if you will. But, you know, my answer generally is, I don't think that hovering out there in the depths of space, there is the answer. You know, I, I think, you know, this, this urge to look out and have the answer brought to us, I think that's ... needs to be inverted. I think that we need to come to the universe with our answer to that. And I think the charge of every sentient living being is to come to their own rationale for their life, their own answer to your question, their own set of activities and desires and achievements and relationships that gives their life meaning and combine to make me feel connected.

    5. SBSteven Bartlett58:01

       One of the things that does make me feel connected is just knowing that the particles that I'm made out of existed at the Big Bang.

    6. BGBrian Greene58:08

       Yes, exactly. Isn't that wondrous? You are the universe constructed in a way that you can reflect on the universe. Now, some would say, "No, no, no, we're special. We're like these divine offspring, you know, made in the image of God." And sure, I mean, I like the way that that sounds, but I find it much more satisfying to describe it the way you did. There were particles that emerged from the Big Bang that coalesced into a form that allowed us to momentarily, 'cause we're here for a brief flicker of cosmic time, to momentarily reflect on our own existence. That's a connection.

    7. SBSteven Bartlett58:51

       One of the things that actually helped me a lot through my life, funnily enough, is, um, is kind of watching what you just showed on the screen there, which was I watched a video when I was younger of them just zooming out from Earth.

    8. BGBrian Greene59:01

       Yeah.

    9. SBSteven Bartlett59:01

       And we talked about feeling insignificant earlier. Um, I mean, there's some of them here. I'll just pick one at random, like this one here, where it's just a, a lady sat on some grass and-

    10. BGBrian Greene59:10

        Yes

    11. SBSteven Bartlett59:11

        ... she, she zooms out further and further and further. And when I saw this, I must have been, hmm, it was a video like this one. I must have been about 14 years old. And at first I had the thought that a lot of people might have, which was, oh, like, none of this matters because we're so insignificant on the grand scheme of things that, like, what's the point? And then I, I had this other thought, which has stayed with me ever since, which is ... It liberated me from worry.

    12. BGBrian Greene59:35

        Yeah.

    13. SBSteven Bartlett59:36

        Because if, if all of my worries are just a speck in this bigger thing, which are a speck in a bigger thing and a speck in a bigger thing, it meant that I could take more risks in my life-

    14. BGBrian Greene59:47

        Yeah

    15. SBSteven Bartlett59:48

        ... and not be encumbered by what will happen if and what will people think and et cetera, et cetera, et cetera, which kind of liberates one to go and pursue whatever they wanna pursue.

    16. BGBrian Greene59:56

        Yeah. Carl Sagan with the Pale Blue Dot, you know, if you're familiar with that terminology, he, he had the, uh, Viking spacecraft, when it was going by Saturn, turn around and take a shot of planet Earth through the gossamer rings of Saturn. And in that photo, the Earth is this little tiny pale blue speck, sort of as we saw in the film as it went by there. And he, in this wonderfully poetic passage, described how everything we care about, everything we love, everything we fight, the rivers of blood that have been spilled to conquer a tiny little fraction of a pixel in space. That gives you a setting where the concerns that you're mentioning of an individual human life, of, of countries, of nations, you realize how utterly small it is in the cosmological setting. And again, um- That to me isn't insignificance, as you were saying, it's liberation

25. 1:01:01 – 1:08:25

    What If Consciousness Is the Foundation of Reality?

    1. SBSteven Bartlett1:01:01

       We have this, um, this spectrum of, I guess, confidence-

    2. BGBrian Greene1:01:05

       Yeah

    3. SBSteven Bartlett1:01:06

       ... in front of us here. And on one end of it, it says low confidence, on this end it has high confidence. And there's five little, uh, figurine type things there next to you.

    4. BGBrian Greene1:01:15

       Yeah.

    5. SBSteven Bartlett1:01:15

       And what I would like you to do is to place them in line with your confidence that the thing is real. So the first one that I'm gonna ask you to place is those mini scales which represent free will.

    6. BGBrian Greene1:01:24

       This guy here, free will?

    7. SBSteven Bartlett1:01:25

       Yes. That's free will.

    8. BGBrian Greene1:01:26

       Yeah.

    9. SBSteven Bartlett1:01:26

       Do you think humans have free will? Are you low confidence or high confidence? I'll push that a further towards you so you can-

    10. BGBrian Greene1:01:31

        Uh, well, uh, I do not think we have free will, and I have high confidence in that assessment, which I guess means low confidence that we have free will.

    11. SBSteven Bartlett1:01:43

        What is free will?

    12. BGBrian Greene1:01:44

        To me, free will is really just the everyday sense that you are the ultimate author of your actions, that the buck stops with you when it comes to the decisions that you make for how you are going to respond one way or another in the moment to moment existence of life. I don't think that freedom of the will is real. And I can give you a quick sense why. It really is an extension of everything that we've already spoken about, which is, you know, when I look at you, I see a man, but I also imagine that I'm looking inside you, and I see your particles. And so you are a man-shaped collection of particles. That is what you are. And each of those particles, and the agglomeration of those particles, are fully governed by the laws of physics. I don't say that we have those laws yet. We have an approximation to them with Schrödinger, and Einstein, and all those folks. But I do believe that there is an ultimate set of principles that guide how your particles behave. You do not have the capacity to intercede in the lawful progression of your particles. So if you raise your hand, it is not you who's doing that, it is the laws of physics guiding the particles in your brain, sending an electrical signal down your arm, causing your muscle to contract or expand, resulting in your hand going up. You don't control the laws that govern those particles. You di-

    13. SBSteven Bartlett1:03:19

        I didn't make the decision?

    14. BGBrian Greene1:03:20

        You did not. You felt that you did. And so the feeling that you and I and everyone else have, that we make decisions and those decisions result in our action, it's a powerful, it's a seductive sensibility. But no, I do not think that you are the place where that choice, if you will, occurred. The choice is actually within the lawful unfolding of the particles. And I can't control that particle motion, therefore, I can't control the decision, therefore, I don't control the motion of my arm.

    15. SBSteven Bartlett1:03:54

        Therefore, I don't control my life?

    16. BGBrian Greene1:03:56

        You don't, in some sense. If you buy into it fully, it can be paralyzing, or you can recognize it, which I do, and I say, "Okay, within that structure, I'm gonna live my life as fully as I can." And I am able, not always, 'cause I'm a human being, but in the best of moments, I can pull back and have a certain objectivity about the things that happen in my life, and I observe them at a remove, as opposed to being completely wrapped up in the moment to moment. Now, that doesn't make me an aloof person. It doesn't make me somebody who somehow is detached, no. It's just, I can analyze the world at multiple levels.

    17. SBSteven Bartlett1:04:44

        So who is and what is guiding those particles to make the decisions that those particles are making?

    18. BGBrian Greene1:04:49

        The best I can say, and I think the best that we can say right now, is that there is some body of law. Now, what does that mean, a body of law? There is some patterns that repeat in the world. Now, you drop an apple, and it falls on Newton's head repeatedly. You can rely upon certain kinds of particle motion because there's certain regularities in the world, and the regularities in the world are what I mean by the laws of physics. They may be articulated mathematically. Our best guess is, as of today, that math is the best language we have for describing those laws. But out there, I think there are some fundamental patterns, and those patterns ultimately are what determine how the particles move. And so that's all that we are. We are a body of particles that move, and that's responsible for why things do what they do. And remarkably, our brains allow us to self-reflect, to look at what we do and analyze it, and when we do that, we tend to ascribe authorship to ourselves. But that's a story that we tell ourselves. It makes us feel good. It makes us feel part of the unfolding. It perhaps has an evolutionary utility that if you feel responsible for what you're doing, maybe it helps you to survive. Maybe that's why this way of thinking was inculcated over the course of generation upon generation. Maybe there's an evolutionary explanation, but fundamentally speaking, I don't think it's real.

    19. SBSteven Bartlett1:06:25

        I was gonna say then, well, maybe the, the particles are trying to survive in this form. But even as I thought about that, I thought, so maybe my particles in making the decisions they make to raise my hand, to go on a holiday with my fiancée, to have kids because they want to survive in this form. But actually, I disappear at some point.

    20. BGBrian Greene1:06:46

        Yes.

    21. SBSteven Bartlett1:06:47

        But my particles don't.

    22. BGBrian Greene1:06:48

        Right.

    23. SBSteven Bartlett1:06:48

        They then become dirt, or someone else, or whatever-

    24. BGBrian Greene1:06:51

        Yes

    25. SBSteven Bartlett1:06:51

        ... or a child. It doesn't seem that they care much about necessarily being in this form.

    26. BGBrian Greene1:06:54

        They don't. I don't think they do. So I don't think they care. I don't even think the word care is applicable to them. The notion of caring is a high level construct That only emerges when the particles are configured sufficiently to yield a complex information processing system called a human brain

    27. SBSteven Bartlett1:07:14

        And consciousness

    28. BGBrian Greene1:07:15

        And consciousness. Now, if you ask me where consciousness comes from, I don't know, sort of as we discussed before, I think it's just physical processes. Let's go with that. Assuming that's the case, this conscious self-awareness invents the idea of caring because it's a useful concept for us to organize our lives and our experiences. This conscious self-awareness inve- invents all the other words, happy, sad, meaning, purpose, morality, activity, action, choice, decision, freedom, will, all human-made. These concepts don't exist out there in the universe. There's no notion of freedom of the will floating in space outside the Andromeda galaxy. This is a selection of ideas that we humans as a species have found to give us utilitarian advantage in organizing our experiences. That's all that it is. That doesn't diminish it. I don't go around trying to erase my sense of self. I accept my sense of self, but I also see it for what it is, a human construct.

26. 1:08:25 – 1:10:31

    Are Animals Conscious Like We Are?

    1. SBSteven Bartlett1:08:26

       Does that mean that consciousness and everything that I am could theoretically just be, as you said earlier, in the sort of pessimistic version of events, random, totally random, like consciousness itself was just the particles came together over a long enough period of time, and then they-

    2. BGBrian Greene1:08:41

       Yeah

    3. SBSteven Bartlett1:08:41

       ... they found this form, and now I can-

    4. BGBrian Greene1:08:43

       It could, and maybe it was random and happened only once on this planet, right? I mean, again, maybe there is life out there, and maybe there's even complex life out there, maybe even, like, as big as us or bigger. But maybe when we encounter those life forms, they have no idea of what it means to have an inner world.

    5. SBSteven Bartlett1:09:04

       This, um... I think it was a physicist said to me that it was a bit of a spiritual, esoteric idea, but they basically said to me that they think consciousness could be, it could come from this sort of original source, and it's divided itself up into the humans-

    6. BGBrian Greene1:09:17

       Yeah

    7. SBSteven Bartlett1:09:17

       ... the bees, the birds to go out there and understand the nature of the universe.

    8. BGBrian Greene1:09:22

       Yeah.

    9. SBSteven Bartlett1:09:22

       And that when we die, we kind of return to the source. But, you know, I'll give birth to a baby. They'll go off into different corners of the, the Earth and look at different things and have different experiences, and it's all feeding back into this central consciousness, which its sole objective is to understand itself. And-

    10. BGBrian Greene1:09:36

        Yeah

    11. SBSteven Bartlett1:09:36

        ... it's funny 'cause I heard this idea from this physicist, and then I, I was in a, uh, somewhere in Europe, and I was driving down the road, and I saw all of these tourists just, like, looking up at a mountain, and they were just, like, looking out at the sea, and they were looking at things that were interesting-

    12. BGBrian Greene1:09:50

        Sure

    13. SBSteven Bartlett1:09:50

        ... which is what we do as humans.

    14. BGBrian Greene1:09:51

        Yeah.

    15. SBSteven Bartlett1:09:51

        And I thought [laughs] kind of makes sense-

    16. BGBrian Greene1:09:53

        Yeah, yeah, yeah

    17. SBSteven Bartlett1:09:54

        ... that we're like, we're actually just like [laughs] consciousness is observing something.

    18. BGBrian Greene1:09:56

        Yeah. No, there's a philosophical position called idealism, and idealism holds that the fundamental truth of reality is consciousness. But fundamentally, everything that I've seen throughout my life suggests to me that that's not how it is. I can't prove it. I hope it's true. But if you ask me what I think is really true, I think that consciousness is something that emerges when there's a sufficient amount of information processing that itself is carried by the motion of particles through various interconnected structures.

27. 1:10:31 – 1:12:32

    What If the Universe Isn’t Infinite?

    1. SBSteven Bartlett1:10:31

       Is my dog conscious?

    2. BGBrian Greene1:10:32

       It is, but I think it's got a different level of consciousness. You can tell when they're feeling good, happy, or sad or frustrated or intrigued. The ears change, the eyes change, the shape of the face. You can't help but ascribe an inner world to that. And again, I always worry that the dogs, like the fish, are like, "These [laughs] humans think they're so damn special, but we actually are well developed, well beyond them, and we're just playing along." In fact, in New York City, who picks up the poop, right? We pick up the poop, so the dog walks along as, like, this, you know, king-like being, and we behind them with these little plastic bags. So who's really in charge? But putting that to the side, I do think that the dogs and the cats have a level of conscious awareness, and I think you go down through the animal kingdom. If you were to ask me, "Does an insect have consciousness?" Mm, then I'm less clear. I suspect not. If you ask me whether a virus or a bacterium has consciousness, I don't think so. I don't think there's adequate information processing capacity in those structures to have the kind of rich inner world that we would normally ascribe to a conscious being, but that's all that I think it is. I don't think that there's some uber universal consciousness that's out there that we go back to when we die. Not that I wouldn't like it. I just don't think it's true. Moreover, I can understand why humans would introduce this idea. Again, it's Ernest Becker and the denial of death. How wonderful to say, "Yeah, our bodies die, sure, but our consciousness, it doesn't die. Our consciousness, it floats off, and it rejoins the universal co-" Wow, that makes you feel good. And we tell these stories that make us feel good, and there's nothing wrong with that. However, I do think it's important that we see them for what they are, which are human-authored stories to compat our own recognition that we are mortal beings.

28. 1:12:32 – 1:13:23

    Could Aliens Have Already Visited Earth?

    1. SBSteven Bartlett1:12:32

       Moving on to the next one-

    2. BGBrian Greene1:12:33

       Yeah

    3. SBSteven Bartlett1:12:33

       ... is the universe there on the little card. We talked about this a little bit, and you've given your answer already, but do you think the universe is infinite?

    4. BGBrian Greene1:12:41

       I don't know, but I'm gonna put it sort of around here. You know, in fact, lately, I should tell you, the work that I've been doing has imagined that the universe is not infinite. So I've been doing a lot of scientific exploration with mathematics with a handful of colleagues and the kind of weird things that can happen if it's not infinite, and it's very interesting. There's a lot of mileage that you can extract from a universe that you go off in that way, and you wind up coming back to your starting point, much like you would on the surface of the Earth. It's a finite extent. But if you ask me in my heart of hearts if I was forced to make a choice, I would say infinite with a medium level of confidence.

    5. SBSteven Bartlett1:13:22

       What

29. 1:13:23 – 1:16:13

    Could Humans Ever Travel Across the Universe?

    1. SBSteven Bartlett1:13:23

       about do you think life Could exist outside of Earth, and I'll say intelligent life.

    2. BGBrian Greene1:13:29

       Intelligent life.

    3. SBSteven Bartlett1:13:30

       Do you think intelligent life exists outside of Earth?

    4. BGBrian Greene1:13:33

       Yeah. So for intelligent aliens, I'm gonna definitely go a little bit more over here. You know, I put it as, uh, it's possible. Obviously, it happened once, therefore it could happen again. You know, obviously intelligence is not somehow contradictory to the way the universe evolves. It can support conscious and intelligent beings, but I think it may be special.

    5. SBSteven Bartlett1:13:55

       Is there not-

    6. BGBrian Greene1:13:56

       Yeah

    7. SBSteven Bartlett1:13:56

       ... a bit of a contradiction here, though-

    8. BGBrian Greene1:13:57

       Yeah

    9. SBSteven Bartlett1:13:57

       ... with these two things, that you think the universe is infinite?

    10. BGBrian Greene1:14:00

        Oh, when I say this, I should say within the observable universe.

    11. SBSteven Bartlett1:14:04

        Oh, okay.

    12. BGBrian Greene1:14:05

        Yeah. So in the entire expanse of the universe as opposed to the observable part, which again is a part that even in principle we could have connection with, then yeah, I would absolutely put it in exactly the same place because there'd be copies of us out there. But if we talk instead about are we gonna get a signal? Are we gonna be visited? Then I put that at much lower confidence. And in fact, I, I would say one thing about the visitation, because you mentioned the interest that people have on aliens. I find it really odd that people are taken with these photographs that are meant to sort of just catch the alien ship as it was racing. If an alien could travel across the galaxy, say, to reach us, they are so technologically advanced that the idea that our archaic airplanes and their cameras could capture a photograph of them is ludicrous. They will be able to evade us in so simply that the idea that we just barely caught them on our cameras is, is absolutely ridiculous. Moreover, if they could travel to us, again, I'm talking about traveling across light-years, right? I mean, our galaxy, 100,000 light-years end to end, right? To be able to traverse that requires a level of technological sophistication that is so beyond anything that we can do. To imagine that beings that advanced would be interested in us, so interested that they would, like, kidnap us, that'd be like saying, "I was walking to the park yesterday. Don't tell anyone, but I kidnapped an ant. There was an ant walking along and nobody was looking, and I sort of kidnapped it to..." We don't do that because it's not interesting. Similarly, we would not be of interest to the aliens because they're so incredibly advanced that this idea that they're abducting us is just ludicrous.

30. 1:16:13 – 1:19:15

    How Time Travel Could Actually Be Possible

    1. SBSteven Bartlett1:16:15

       Is it gonna be possible-- You know, we were talking earlier on about the, the possibilities that artificial intelligence is gonna unlock. Is it possible within the laws of physics for us at some point when we get sufficiently intelligent to travel across the universe?

    2. BGBrian Greene1:16:28

       It's a, that's a, it's a great question. It's a tough one. So if the technological advancement was simply making our ships faster, no, because even if you travel near the speed of light, which is the ultimate speed limit, you know, to go to the nearest star, Alpha Centauri, would take you four years even at the speed of light to get there, right? And then if you actually wanna go not just to the nearby star, but to actually across the galaxy, again, you're talking 100,000 years to do that. So that brute straightforward approach will not succeed. However, there are exotic ideas of things called wormholes you've probably encountered. These are these ideas of a wormhole is like a tunnel. What is a tunnel? On Earth, a tunnel is a shortcut that gets you from here to here without having to go over the mountain, right? Tunnel it right through. There's an analogous idea that people float in the universe, where to get from here to there, there may be a shortcut, a kind of tunnel that connects them and is a quicker way of getting from point A to point B. We don't know if these tunnels through space exist. We don't know if they existed, whether we could actually get through them. And so it's a highly speculative idea. But if they do exist, and if we one day can create them and manipulate and control them, then at least in principle, we could take two distant locations like this corner and this corner. But imagine that we could manipulate this surface, fold it together to bring the two corners next to each other, and build a little tunnel between them. Then we could go from one end to the other by going through that shortcut. That's a very far-out idea.

    3. SBSteven Bartlett1:18:16

       But there's no evidence of this.

    4. BGBrian Greene1:18:16

       There's no evidence at all. Now, now, let me just say again, much as we discussed earlier, this idea is not just some wild late-night musing of a physicist. It comes out of the math of Einstein's general relativity that these wormholes could exist. In fact, Einstein himself in 1935 wrote a paper with a colleague, Nathan Rosen, where they introduced this idea that we now call wormholes. We're no further along in knowing whether wormholes are real than Einstein was back then. We've analyzed them. We've developed the mathematics. You know, science fiction has taken this idea. You know, in, in Interstellar, I believe Matthew McConaughey goes through a wormhole. Jodie Foster went through one in Contact. You know, they're, they're a ubiquitous feature of science fiction trying to allow for the kinds of travel across the galaxy that otherwise would be impossible. But whether this is actually real, no- nobody knows.

31. 1:19:15 – 1:21:46

    Who Was the Smartest Person Who Ever Lived?

    1. SBSteven Bartlett1:19:15

       What about time travel?

    2. BGBrian Greene1:19:17

       Yeah.

    3. SBSteven Bartlett1:19:18

       Can, can we travel backwards in time within the laws of physics?

    4. BGBrian Greene1:19:21

       Yeah, that is the, the, the way of phrasing it, because if you ask me the reverse question, can we travel to the future? I would say yeah, that kind of time travel we're highly confident of, so I don't have a little thing for that. But let's call, you know, this is time travel to the future, right? I put it very, very high confidence for that.

    5. SBSteven Bartlett1:19:41

       You think we can travel to the future?

    6. BGBrian Greene1:19:42

       Yes, in principle. Executing it, a different story. But one of the things that emerges from Einstein's special and general relativity is that the way time elapses for you and for me is variable depending upon how fast we move and the strength of the gravity that we experience. So for instance, if I want to see what your life would be like 60 years from now, Einstein laid out a blueprint for how I could do that. I build a spaceship. I travel out into space near the speed of light. I go for a certain period of time, maybe about six months. I turn around, I come back six more months. I come back, I'm one year older, six months, six months. But you will be 60 years older if I traveled sufficiently close to the speed of light because my clock would be ticking off slow compared to your clock. Your clock went through 60 years while my clock went through one year. There is no physicist who knows what they are talking about who disputes this. Now, it's not controversial, but if you then say to me, "Well, do it," I'd say, "Ugh, I don't know how to build a spaceship that goes that fast, at least not yet."

    7. SBSteven Bartlett1:20:56

       You would only have aged one year.

    8. BGBrian Greene1:20:57

       Correct.

    9. SBSteven Bartlett1:20:57

       But I would have aged 60 years.

    10. BGBrian Greene1:20:58

        Correct.

    11. SBSteven Bartlett1:20:59

        Could you then go back?

    12. BGBrian Greene1:21:00

        Ah, I don't know. And if you were to ask me to give my confidence on going back, I would say it's pretty, pretty low. People have written proposals for how you could go back. They do involve things like wormholes. That is one possibility because if you have a, have a tunnel from one point in space to another, if you then move the openings at different speeds, their clocks will tick off at different rates. This clock may be before this clock. So if I travel this way, I'm going one way in time. If I'm traveling that way, I'm going the reverse way in time. But again, like we said before, we don't know if wormholes are real. If they are real, you might in principle be able to travel back. But if you ask me do I think that you can, low, low confidence that you can travel back.

32. 1:21:46 – 1:24:57

    Could AI Become the Next Einstein or Newton?

    1. SBSteven Bartlett1:21:46

       You've used the word Einstein a few times.

    2. BGBrian Greene1:21:48

       Yeah.

    3. SBSteven Bartlett1:21:48

       And I think, uh, this generation, you know, we, we exist with AI now and calculators and all this incredible knowledge that has come from sort of standing on the shoulders of so many of these giants. Who do you think is the smartest person to have ever lived in your estimation?

    4. BGBrian Greene1:22:01

       It's a tough one. People often make it an easier question by saying, "Who's smarter, Isaac Newton or Albert Einstein?" And first my answer is, when you're talking about that level, it doesn't matter who's smarter. But if you really press me, I think I'd say Isaac Newton because Newton kind of went from nothing to develop the laws of physics. There were people before, but there wasn't really a mindset that the universe should be articulable in a few mathematical equations. And yet here comes along Isaac Newton, and he writes down the equation that we teach high school kids, F equals MA, force equals mass times acceleration, which governs just about everything in the world around us, non-quantum mechanically. He writes down the law of gravity, F equals GM one M two over R squared, articulating how the gravitational force works, and he was sort of doing this on-- He invents calculus in order to be able to use that as a tool for articulating the laws of physics. I mean, he kind of went from no real architecture of physics to a solid mathematical formulation. Einstein came along, and there was already a lot of physics. I think going from nothing to the first step, that's hard to imagine.

    5. SBSteven Bartlett1:23:24

       Was Newton to some degree like neurodivergent? How could he be so genius?

    6. BGBrian Greene1:23:29

       I wish I knew the answer to a question like that. Like, you know, what is it inside their heads that allows them to do the things that just are superhuman or feel superhuman to us? I have no idea. Now, Newton was a kind of weird fella, right? He was deeply religious, as makes sense for the time. He was ultimately, you know, in the government tracking down counterfeiters and, and hanging them. I mean, there seems to be a certain curmudgeonly side of him that was also part of his genius. Uh, he once reportedly took a, a knitting needle and stuck it in his eye between the ball and the socket to see if he could manipulate sight through mechanical pressure. I mean, who does these kinds of things, right? So he was a different thinker, but clearly one who ultimately was able to see deeper. You know, and as you said, you know, standing on the shoulders of giants, you know. And there was a certain humility that came through him. There's a beautiful quote where he describes himself as a boy playing on the seashore, having found a smoother shell and prettier pebble than most while the great ocean of truth, he said, lay before me all undiscovered. He knew that we were just on the shore, and we'd taken our first baby step into the cosmic ocean, and there was much more to be discovered.

33. 1:24:57 – 1:28:40

    Ads

    1. SBSteven Bartlett1:24:58

       Is it conceivable that the next Newton or I-Einstein is gonna be an artificial intelligence? Could it be Claude?

    2. BGBrian Greene1:25:05

       Yes, it could absolutely be. Look, I, I like to think of scientific creativity or creativity in general in sort of three main buckets. It's a coarse organization, but I think it's helpful. One bucket of creativity is the ability to see the landscape of possibilities more fully than a mortal human being, and there's a lot that emerges from the ability to do that. For instance, you know, if you're a chess player, you, you can see the spectrum of allowed moves that are available to you more than the ordinary chess player. You know, if you're a scientist, you can sort of see the landscape of ideas and equations that you might bring to bear on a puzzle more than somebody else, and that is what allows you to achieve greatness. Artificial systems, they have the entire landscape, right? They've read the entire internet. They've read every textbook. They know everything that we have ever developed. So in that kind of creativity, obviously they're going to excel, and we've seen that. Y- A human can't beat an AI any longer in chess. A human can't beat an AI system in Go, right? I mean, this famous example with, uh, AlphaGo, right? Move 37 has become this sort of iconic move where, you know, Lee Sedol, the world champion, is playing and you can see it on his face. The AI makes a move, and his ... he smiles momentarily, and he's like, "Oh, it messed up." And then his face changes, because he slowly realizes that wasn't a mistake. Even the commentators, if you listen to them, they were like, "Oh my God, the AI has made a mistake. What a blunder the AI has made." And then within 20, 30 seconds, they're like, "Oh. Oh, that was genius." Why? The AI could see the spectrum of possibilities more than a human being. So at that level of creativity, AI will win. Second bin of creativity, second bucket, is putting together divergent ideas in a way that no one has thought of before and in that way making progress. You know, that's kind of what Einstein did in general relativity, put together Riemannian geometry and Newtonian gravity, yielded the general theory of relativity. But again, AIs, since they know everything that we've ever developed, can combine things in a way that we would never have thought of. The final domain is the one where somebody comes up with something that nobody has ever imagined, ever thought of. It's not just putting things together. It is radically new. That's the tough one. We're still able to win in that category. There are examples where people just come up with things that, where did it come from? How did they think of that? If you develop an artificial system and allow it to have a life, allow it to grow up, put it in an environment where it actually has experiences of the sort that an Isaac Newton had, could it be that that system then develops to a place where it can do the things that we'd like to think are exclusively human, coming up with something that is not previously represented in the database on which the AI system has trained? And so even this third, more difficult or more pristine bucket of creativity, could an artificial system do that? I don't think there's

34. 1:28:40 – 1:30:08

    How AI Could Accelerate Science—and Even Tackle Mortality

    1. BGBrian Greene1:28:40

       a barrier. [page flips]

    2. SBSteven Bartlett1:28:41

       I've done almost 700 interviews with some of the most interesting people in the world, and one of the things you learn, which is unexpected, is that vulnerability is the doorway to connection. And after sitting here for two, three hours with a guest, I feel a deep sense of connection to them. And as they leave, what I get them to do is to write a question in The Diary of a CEO. We've taken all of the questions from The Diary of a CEO. We have put the question here on this card with the name of the person that wrote it. So you can sit at home, as I do with my fiancée and my colleagues at work and other people in my life. Whenever we get a minute, we play The Diary of a CEO conversation cards, and it is incredible what happens. These are great if you're in a romantic relationship and you wanna connect your partner more. These are also great if you're in a team and you want to bond your team together. And I have to say, they're also great for families that wanna learn more about each other and that need a good excuse to spend some time in a digital world, in the analog environment, connecting human to human. It is remarkable what the right question at the right time can do. Go to thediary.com and you can get these conversation cards right now. [page flips] There should be a button just down below here, and if it says Subscribe, you're already subscribed. If it says Subscriber, that means you're not yet. And if you're not subscribed, please could you do us a favor and hit that button? It helps the show more than you know, and according to the algorithm, you're someone that watches our show, but you haven't yet hit that button. Thank you so much. [page flips]

35. 1:30:08 – 1:33:07

    Could AI Evolve Faster Than Humans Ever Could?

    1. SBSteven Bartlett1:30:08

       This comes to one of our questions-

    2. BGBrian Greene1:30:09

       Yeah

    3. SBSteven Bartlett1:30:10

       ... which is the skull there.

    4. BGBrian Greene1:30:11

       Yes.

    5. SBSteven Bartlett1:30:11

       Which is, do you believe it will be possible to live forever? And again, I think about this in the context of AI, where you said it'll be able to understand that, take us to the limit. It's hard to, it's hard to understand, um, how that isn't a solvable problem. In fact, a lot of the smartest people on Earth, including, I think Elon Musk said it recently, that living another 100, 200, 300, 400, 500 years-

    6. BGBrian Greene1:30:33

       Yeah

    7. SBSteven Bartlett1:30:33

       ... seems to be within the laws of physics.

    8. BGBrian Greene1:30:34

       Yes. I think that is absolutely within the realm of possibility, but 500 years is so different from forever. Like, when I hear forever, I'm taking it kind of literally.

    9. SBSteven Bartlett1:30:47

       Oh, okay. Yeah.

    10. BGBrian Greene1:30:47

        And, and so if, if forever doesn't mean 500 or 1,000, if it means never ceases, then I have no confidence that that kind of existence will be possible.

    11. SBSteven Bartlett1:31:02

        What about 500 years?

    12. BGBrian Greene1:31:03

        500 years, yeah, I would say, again, not in our lifetime, uh, which is sad. I would, I would put that at, at reasonably high confidence that, you know, hundreds of years will be within our ability.

    13. SBSteven Bartlett1:31:15

        If we are on this sort of exponential of intelligence, then it, you know, and if 2021-

    14. BGBrian Greene1:31:21

        Yeah

    15. SBSteven Bartlett1:31:22

        ... we couldn't solve that math equation-

    16. BGBrian Greene1:31:23

        Yeah

    17. SBSteven Bartlett1:31:23

        ... you're talking about, but in 2026 we can.

    18. BGBrian Greene1:31:25

        Yeah.

    19. SBSteven Bartlett1:31:26

        And you've got trillions of dollars now pumping into these artificial intelligence systems to make them smarter and more powerful. It is, it, it is conceivable that if we're on an exponential curve here, it could be within our lifetimes that there is a discovery made about our telomeres and whatever else it might be that the guests on my show have talked about. That means we can theoretically.

    20. BGBrian Greene1:31:43

        But let me tell you why I'm, I'm skeptical of that. Number one- Right now, we have a certain kind of artificial intelligence. It's basically large language models. And that's a certain paradigm where the system is trained on an enormous number of tokens, an num- enormous number of words, you know, basically the entire internet. And based upon the statistics and the statistics of the statistics of the statistics of how the words are arranged, the system is able to provide answers to questions that are coherent and, and, and insightful and so forth. There isn't necessarily an unlimited capacity of that kind of artificial intelligence to continue to improve, right? And so it's not obvious to me that it's just a matter of pumping billions and billions of dollars, building ever larger data center, putting them in space, wherever you're gonna do, and the more money you put in and the more data you have and the more computer power you have, the better it's going to be. Uh, that's not obvious to me that that will continue up that exponential curve, and that's why I'm hesitant to say in our lifetime. It may take a number of lifetimes to develop the kind of artificial intelligence necessary to advance the s- kinds of scientific problems that you're talking about. But look, I'd be thrilled if it's our lifetime. I'd be thrilled if I'm wrong, and these systems are up to the task.

36. 1:33:07 – 1:41:11

    Could AI Become an Existential Threat to Humanity?

    1. SBSteven Bartlett1:33:07

       One of the terms that has emerged in the world of AI recently, um, is this term recursive self-improvement.

    2. BGBrian Greene1:33:13

       Yeah.

    3. SBSteven Bartlett1:33:13

       Recursive self-improvement is the concept where an AI becomes intelligent enough to write its own software, design its own hardware, or train its own successors without human intervention. And once this loop begins, the upgraded AI uses its superior intelligence to build an even smarter version of itself, which then builds an even smarter version, and so on. Because computer systems operate in seconds rather than human evolutionary timescales, this feedback loop could trigger an exponential, quote, "intelligence explosion," rapidly taking AI from human-level capability to superintelligence within days or hours.

    4. BGBrian Greene1:33:43

       Yeah.

    5. SBSteven Bartlett1:33:43

       And the big AI leaders, Dario at, um, Anthropic, has recently published an article warning that we're edging closer to that. Sam Altman has said the same. Demis has said the same. Um, Elon has talked about this as well recently. And their timelines for this explosion in intelligence, because of the AIs being able to train themselves, ranges from two years to five years, placing them between 2026 and 2029. And Dario, who's, uh, the CEO of the biggest model called Anthropic Claude, um, has stated that AI systems outperforming most humans across all human tasks, including software engineering, could arrive within two to three years. And Anthropic has been warning that full recursive self-improvement could arrive by 2027 to 2028. Demis at Google is citing 2029 as a real possibility. And Sam Altman says this decade. I mean, uh, Brian Johnson tweeted yesterday, "Pace yourself as if you'll live to 500, because you may." [laughs]

    6. BGBrian Greene1:34:38

       [laughs]

    7. SBSteven Bartlett1:34:38

       "Because you, because you may." [laughs]

    8. BGBrian Greene1:34:39

       Look, I'm all for the possibility that these systems will take off in a way that hopefully we are, uh-

    9. SBSteven Bartlett1:34:49

       Hopefully

    10. BGBrian Greene1:34:49

        ... hopefully working in a way that allows the kinds of future that you're envisioning, that we are here and-

    11. SBSteven Bartlett1:34:56

        Would it be a good thing?

    12. BGBrian Greene1:34:57

        Well, you know, uh, it, it would be seductive. I mean, and, and, and if someone was to present you with the opportunity to live for, to 500 years, I think many people would opt in for that. It's very hard to say, "Uh, you know, 100 years is enough," and I just... You know, there are people who do that, who will look at the world and say, "It's enough," you know? "I'm, I'm, I'm done." But back to the prognostications that are, are being made. Look, it's absolutely the case that the AIs will self-improve through the very process that got us here, but on a timescale that's tiny compared to the timescale that got us here. I'm skeptical that by 2029 this'll really be the case. Uh, uh, let's see, right? I mean, this is a very short term, right? So we will know in a few years whether this is the case.

    13. SBSteven Bartlett1:35:51

        How many years has it taken [laughs] living organisms to get from a single-cell microbe or whatever to understanding string theory? [laughs]

    14. BGBrian Greene1:35:59

        Yeah. So, you know, the first life on our planet formed roughly within the first billion years, you know?

    15. SBSteven Bartlett1:36:05

        Okay.

    16. BGBrian Greene1:36:05

        People debate exactly where that is. And, you know, we're now roughly, call it, you know, 5 billion years in. So call it roughly 4 billion years.

    17. SBSteven Bartlett1:36:13

        And the... And, and a computer going from zero to being smarter than every human on Earth has taken-

    18. BGBrian Greene1:36:17

        Yeah. Well, it depends where you-

    19. SBSteven Bartlett1:36:19

        ... decades

    20. BGBrian Greene1:36:19

        ... where you start the gods, right?

    21. SBSteven Bartlett1:36:21

        Oh, true.

    22. BGBrian Greene1:36:21

        Because again, if you think about these systems as we, they needed us.

    23. SBSteven Bartlett1:36:26

        Uh-huh.

    24. BGBrian Greene1:36:26

        Without the internet and all the data, what would they have trained on, at least this version-

    25. SBSteven Bartlett1:36:32

        Sure

    26. BGBrian Greene1:36:32

        ... of artificial intelligence? If it's the computer, the artificial system that's self-tinkering, then yeah, there's this feedback that will yield an exponential growth. And if there's no barrier, and there may be, right? There may be a barrier to the kind of artificial intelligence systems that we have. We may allow it to iterate, and it iterates, and it, sure, it improves, but it doesn't improve like this. It improves like this. It could asymptote. It could approach a maximal intelligence compatible with this version of the artificial system. And so it won't skyrocket. It could do this, and we don't know the answer, which curve is the right one.

    27. SBSteven Bartlett1:37:13

        Give me a rebuttal to that.

    28. BGBrian Greene1:37:15

        A rebuttal to it being the exponential curve?

    29. SBSteven Bartlett1:37:18

        Give me a rebuttal-

    30. BGBrian Greene1:37:19

        Oh, oh, you're asking the system. [laughs]
37. 1:41:11 – 1:45:21

    Can AI Ever See the World the Way Humans Do?

    1. SBSteven Bartlett1:41:11

       So Demis, and I use Demis because Demis is running the biggest AI company, said that since the design of machines is one of th- these intellectual activities, an ultra-intelligent machine could design even better machines. If the exponential continues, which is not certain, but now has a decade-long track record supporting it, then it cannot possibly be more than a few years before AI is better than humans at essentially everything. The combination of intelligence, agency, and unpredictability is a recipe for existential danger-

    2. BGBrian Greene1:41:38

       Yeah

    3. SBSteven Bartlett1:41:38

       ... not because AI is evil, but because it's complex in ways we don't fully understand yet. If a system can improve faster than humans can evaluate those improvements, the normal safety feedback loop breaks down. You cannot catch problems before they compound.

    4. BGBrian Greene1:41:51

       He's absolutely right. You know, the, the problem with exponentials is that they grow so quickly that by the time you see them, it's too late to do anything about it. I mean, what happens with a pandemic? With a pandemic, you know, it starts off slow, nobody cares, nobody's paying... It's a story in the news, a story in the news, starts to get... By the time it becomes a real story, the pandemic is at the part of the exponential curve that makes it very difficult to address the problem itself. And the same thing, you know, could easily happen here, that the increase in intelligence, and I'm glad Demis phrased it that way, it may not be that it's intrinsically evil to have this kind of powerful intelligence. It just may act in ways that are so alien to us, so foreign to us, so unexpected to us, that we don't know how to deal with it, and moreover, it may not necessarily be beneficial to our existence. Now, as I said before, I'm perhaps a minority when I say I can imagine that we work with the AI and co-develop into something that we can't even predict today. That seems to me a real possibility.

    5. SBSteven Bartlett1:43:03

       And that's also the temptation.

    6. BGBrian Greene1:43:05

       Yeah. You know, I have a friend, uh, Michael Douglas, who's a brilliant physicist, and he said to me, "We physicists, we should choose the final problems that we work on because within a few years [chuckles] we'll be out of business because the AI systems will just be doing it all." And that's both exciting and terrifying because as a physicist, you know, your, your lifeblood is looking out at the world and finding puzzles and trying to find the explanations for them, and if you can just put it into an AI system and it generates the answer, yeah, there can be a certain existential angst about what your role is at that point, but it's also exciting because maybe we will get answers to questions that we thought we would never get in our lifetime.

    7. SBSteven Bartlett1:43:52

       Did you say y- you're friends with Yann LeCun?

    8. BGBrian Greene1:43:55

       Yeah.

    9. SBSteven Bartlett1:43:56

       And did you say he thinks we should just pull the plug?

    10. BGBrian Greene1:43:58

        When you confront Yann and say, "Dude, aren't you worried about what's gonna happen with this?" He's like, "Ah, don't worry. Just pull the plug if there's a problem."

    11. SBSteven Bartlett1:44:09

        Oh, oh.

    12. BGBrian Greene1:44:10

        Yeah. His view is the difference between the AI systems that we have today and the AI systems that we need for tomorrow, if you really want this to continue, is they can't just be probabilities and statistics based on words. The AI systems need to have some inner model of the world as we do, right? I mean, if I take this cup here and I push it, I have an inner model of what it would take to move it without spilling, and I have an inner model of what it would take to spill it. I won't actually do it because it would make a mess. That's not just statistics and probabilities of words. That's a model of how reality functions. And that's what he and many others have been developing. A world model together with the probabilities of large language model or some weird hybrid or something else we haven't thought of, that may be the next phase of artificial intelligence. But of course, Demis and others might say the LLMs, through self-improvement, maybe they would develop that world. Maybe they would, on their own, get to the place that you would think that we humans would need to inject something extra.

38. 1:45:21 – 1:47:59

    What Happens to Humanity in an Age of Abundance?

    1. BGBrian Greene1:45:21

       Who knows?

    2. SBSteven Bartlett1:45:21

       'Cause if I, like... If I get this glass here-

    3. BGBrian Greene1:45:23

       Yeah

    4. SBSteven Bartlett1:45:24

       ... and say, if I say to the AI, "What happens to this if I push it in that direction?"

    5. BGBrian Greene1:45:32

       If you push that mug, it'll slide across the table, and depending on how hard you push, it could knock into the plate or slide right off the edge. Now, again, it simply is relying upon the fact that it's read everything on the internet, and there are physics textbooks, there are conversations about things falling, and it bases its response by drawing on those collections of words.

    6. SBSteven Bartlett1:45:55

       Isn't that what I'm doing as well?

    7. BGBrian Greene1:45:56

       I don't know. What is... How does human intelligence work? Certainly, evolutionary psychologists have asked the following question: Are we like a blank slate and we simply learn about the world, people tell us, we experience, and so forth, or is there something more innate? And I think there is strong evidence that we have a kind of innate physical intuition about the world that's really been passed down through the generations, not that you can pass down F equals ma or Newton's laws to your children because you learned. Of course, that's silly. But there is an evolutionary advantage to being able to quickly assess the world and figure out how to act, right? Those of our forebears who could not throw the rock or the spear, they're the ones who didn't get the next meal. Those of our forebears that had a slightly better predilection for ingesting experience and codifying it in some understanding of how the world actually works, they're the ones that survived. And so they can pass down that predilection, and I do think that that's part of how we assess the world. I don't think we're complete blank slates in that sense.

    8. SBSteven Bartlett1:47:06

       Would make sense. Babies are born with some kind of intelligence.

    9. BGBrian Greene1:47:09

       Yeah.

    10. SBSteven Bartlett1:47:09

        They grip fingers. But, but, but that is in part because the, the parent has passed that on. And so-

    11. BGBrian Greene1:47:14

        In part

    12. SBSteven Bartlett1:47:14

        ... an AI could pass...

    13. BGBrian Greene1:47:15

        Yes, that's right. When you talk about the AI systems themselves being evolutionary, yeah, they certainly do pass down the achievements of generation N to generation N plus one. That is certainly part of this iterative process, without a doubt.

    14. SBSteven Bartlett1:47:30

        What a weird world we're living in.

    15. BGBrian Greene1:47:31

        Yeah.

    16. SBSteven Bartlett1:47:31

        It's so crazy. [chuckles] So- sometimes I think, but I imagine through history everyone's thought like, "God, what a time to be alive."

    17. BGBrian Greene1:47:37

        Yeah. We are living through a rapid change that is a little unprecedented.

    18. SBSteven Bartlett1:47:42

        How do you think one should contend with all of this? 'Cause people are concerned. Change is-

    19. BGBrian Greene1:47:45

        Yeah

    20. SBSteven Bartlett1:47:45

        ... not something that we love at this rate.

    21. BGBrian Greene1:47:48

        You know, again, I think people will cope in many different ways. You know, if you can stay open and excited to the possibilities and have the flexibility

39. 1:47:59 – 1:50:49

    Could AI Ever Become Truly Conscious?

    1. BGBrian Greene1:47:59

       of change.

    2. SBSteven Bartlett1:48:00

       Oh, uh, one of the things I've been thinking a lot about lately is Elon's out there saying that we're heading to an age of abundance. He's kind of shifted his perspective from this doomerism to-

    3. BGBrian Greene1:48:07

       Yeah

    4. SBSteven Bartlett1:48:07

       ... age of abundance, and then h- part of his narrative there is we won't need money because when you've got robots and AI and more energy, then we're not gonna have to worry about food and these kinds of things or bills, whatever. But still, humans pursue scarcity.

    5. BGBrian Greene1:48:21

       Yeah.

    6. SBSteven Bartlett1:48:22

       We, we pursue status. We want... You know, humans want the home on the end of Miami Beach with the best plot, and there's, there's a f- there's finite numbers of these things that a lot of humans pursue, even like academic discovery, Nobel Prizes.

    7. BGBrian Greene1:48:35

       Yeah.

    8. SBSteven Bartlett1:48:35

       There's a finite number of them and we pursue them, so there's... One would argue that there's still gonna be a, a competition. Uh, p- humans are still gonna strive for things, right?

    9. BGBrian Greene1:48:45

       Why do we do that?

    10. SBSteven Bartlett1:48:46

        Yeah.

    11. BGBrian Greene1:48:47

        Right? And part of the reason is if you know that you're gonna die, if you know that your life is finite, there can be an urge to make your mark, to do something special, to be out of the ordinary so that in some symbolic way you continue to exist even after you are gone, right? I mean, you know, Elon Musk, yeah, after he's gone, uh, people are gonna talk about him for a long, long time, right? Because he had a radical impact, and who knows where it will go. He's got many productive years still left. And so, yes, there is this natural tendency to seek something that will allow you to symbolically persist after you are gone. Now, if we all realize that that is part of human motivation, maybe as a species we could begin to shift, right? It isn't the case that we have to always be the way we have been. Historically, that's the way we have been. Kings wanna be kings in part because they have the power. If they have the power, they have the hegemony. They, in a sense, exist even when they are gone. Their progeny. Why do we have descent of monarchies? Because the king continues to exist through the king's progeny. And so, yeah, could we perhaps get to a place where we shed That way of being because we're in a world of abundance where the whole notion of scarcity is artificial and we're only inventing it, we realize, in order that we can feel good and special and maybe we can find other ways to feel good and special. I allow for that possibility. I'm not particularly optimistic that that's what will happen. On the flip side, I'd say it's easy to say that money won't matter when you have a trillion dollars, right? Right. I, I mean, you know, you just have to sort of see this stuff in context. But yeah.

    12. SBSteven Bartlett1:50:42

        We have one more little, uh-

    13. BGBrian Greene1:50:44

        Yeah

    14. SBSteven Bartlett1:50:44

        ... souvenir thing there. And this is kind of what we're talking about, which is robots. Do you think AI

40. 1:50:49 – 1:54:16

    Why Go Vegan? The Case for Rethinking What We Eat

    1. SBSteven Bartlett1:50:49

       can become conscious, is the question.

    2. BGBrian Greene1:50:51

       Yeah.

    3. SBSteven Bartlett1:50:51

       High confidence or low confidence?

    4. BGBrian Greene1:50:52

       Yeah, I'm pretty high confident on that. You know, again, as I'm saying before, I just see consciousness as a physical process, and it's a matter of, in one way or another, achieving that physical process in an artificial system, and I don't see a fundamental barrier to doing that.

    5. SBSteven Bartlett1:51:11

       I was thinking about how laws would have to potentially change if, if we considered robots to be conscious and they lived in our homes.

    6. BGBrian Greene1:51:18

       Yeah.

    7. SBSteven Bartlett1:51:18

       Would they then get rights?

    8. BGBrian Greene1:51:20

       I think that's something we should think about now, actually.

    9. SBSteven Bartlett1:51:22

       Really?

    10. BGBrian Greene1:51:23

        Uh, yeah, it's a, it's a very tricky, uh, idea. I mean, you know, it's one thing, you know, to pull the plug on a, on a light bulb. It's another thing to pull the plug on a sentient system. And we may well find ourselves in that situation. The, the, the challenge, the challenge is it's virtually impossible to ever prove sentience, right? I mean, you know, as we look at each other, we each afford the other consciousness. I believe that you are conscious. You believe that I am as well. Why? We're more or less, you know, we're physically constructed more or less the same way. We're part of the same species. Uh, our body language, our speech is so similar in the grand scheme of things that we afford the other what we internally experience. But we don't know it, right? You don't know that I'm conscious. I could be faking it. I could be a really good artificial zombie that speaks and talks, but there's nothing going on inside. And the same could be true for you. And what that means is when we are with these artificial systems that don't have our lineage, they're not part of the same species, they don't necessarily look like us, they don't have the upbringing that we had, and so on and so forth, will we be willing to agree that they're conscious if they tell us that they are? I mean, if the artificial system says, "I really am. I'm, I'm feeling exactly the thing that I read about in your internet. I'm, I'm, I'm feeling love," or, "I'm feeling depressed," if they say that to us, we say, "No, no, no. You're just mimicking. You're miming the kinds of things that human beings have said. There's nothing going on inside. There's nothing, there's no world inside there." How do we ever get beyond that? And I don't know the answer to that question, even though I strongly believe that there's no logical, fundamental barrier that prevents the system from saying that and from telling the truth.

    11. SBSteven Bartlett1:53:25

        And electrical circuits within that system causing it to behave in such a way, when it's scared, when it's in love-

    12. BGBrian Greene1:53:30

        Yeah

    13. SBSteven Bartlett1:53:30

        ... where it cuddles you and because that's what the electrical circuits told it to do.

    14. BGBrian Greene1:53:34

        Yes, but is there an inner world associated with that or is it just going through the motions? Here's how I think it's gonna likely turn out. We'll have these artificial systems, they'll start to say these things. At first, we'll be like, [laughs] "Come on, come on, come on. It's not, not real." But we'll start to get used to them behaving just like we in the sense of having these inner worlds. And sooner or later, through a process that's so perhaps slow that we don't even notice it, we will afford them consciousness. We will talk to them as if they're conscious, we will imagine that they're conscious, and ultimately, we will treat them as if they're conscious. Now, I hope that we do that in a, in a

41. 1:54:16 – 1:56:58

    What Happens at the End of Time?

    1. BGBrian Greene1:54:16

       good way. We have a terrible history of treating conscious beings in a respectful way, even in the same species, right? We've done terrible things to each other, even though we afford consciousness. We do terrible things to animals. I'm vegan. I don't eat any animal products. I think that's not the way to treat a living system that has some level of conscious awareness. I do eat plants. I don't think plants have a sufficiently high level of consciousness, if at all, that I'm concerned about cutting them and eating them.

    2. SBSteven Bartlett1:54:49

       Have you always been vegan?

    3. BGBrian Greene1:54:50

       I've been vegan since 1993.

    4. SBSteven Bartlett1:54:53

       Oh, damn, since how old?

    5. BGBrian Greene1:54:54

       So I've been vegetarian since I was nine years old. And so that's how I treat living or conscious beings because I don't think it's right to treat them that way.

    6. SBSteven Bartlett1:55:06

       What was the catalyst for that decision?

    7. BGBrian Greene1:55:07

       Well, when I was nine years old, it was very flat-footed. My mother cooked spareribs, and for the very first time, I realized what meat was. I'm a city kid. I grew up where meat was in cellophane. You buy it wrapped at the supermarket. But when the meat came on a bone, I was like, "Wait a second. What is thi-" I was like, "Oh my God, this is like the rib of an animal." And I was like, and, and I said, I'm, I took it and I said, "I'm never gonna eat meat again." Later on, I did eat, you know, cheese and milk. I wasn't vegan at that point. But when I was a professor at Cornell in the 1990s, I went to an animal sanctuary in Watkins Glen, New York, where they showed you what happens to these animals when they are treated like milk factories. You know, what happens to the cows, and it's, it's awful. And within 72 hours after visiting that animal sanctuary, I said, "I'm done. I'm not participating any longer. I'm not gonna eat or drink or imbibe any living, any substance that came from an animal." And so that was the end for me.

    8. SBSteven Bartlett1:56:14

       For some people, it might be somewhat surprising to hear that from a physicist

    9. BGBrian Greene1:56:19

       I agree. It's inconsistent because if I believe, as I do, that you and I are just a collection of particles in one configuration, and the cow or the pig is just a collection of particles in a different con- what does it matter if you eat particles in one configuration that we call a cow or another configuration that we call a carrot? But as a human being, I allow the other parts of me to shine through, and I look at that collection of particles that happens to be a cow, and I say, "It just doesn't feel right to me to eat that collection of particles. It just doesn't feel right, and I don't wanna do it."

42. 1:56:58 – 2:11:43

    What Could Matter More Than What You Value Most?

    1. SBSteven Bartlett1:56:59

       Brian, you've written many fascinating books. I've got some of them here. I th- I think there's an- one other that I'm missing, I believe.

    2. BGBrian Greene1:57:04

       Yeah, there's, uh, more of a kids book, I think. Uh-

    3. SBSteven Bartlett1:57:07

       Nice, a kids book

    4. BGBrian Greene1:57:07

       ... yeah.

    5. SBSteven Bartlett1:57:08

       For my listeners at home, what is the most interesting thing that we haven't talked about that we should've talked about that exists within your works that I guess is relev- either fascinating or somewhat relevant to their everyday life?

    6. BGBrian Greene1:57:21

       Yeah. Well, I'm gonna go more on the fascinating than relevant to everyday life.

    7. SBSteven Bartlett1:57:24

       Okay.

    8. BGBrian Greene1:57:24

       As you know, I'm pretty esoteric [laughs] in these kind of things. But in the book Until the End of Time, I, I try to give the reader a sense of how we got here, but I also then turn to the future and try to give them a sense of what will be if we go arbitrarily far into the future. And yeah, that's it. I used a metaphor of the Empire State Building, which I, I think helps you get a feel for what the universe will be like if you take the current understanding of the laws of physics and extrapolate arbitrarily far into the future. And so w- to try to give people a sense, I ask them to imagine that every floor of the Empire State Building represents an era of time that's 10 times longer than the floor below. So, like, at the, at the ground floor, that's, like, one year, and then the next floor 10, next is 100, 1,000, 10,000, 100,000, and so forth. Exponentially larger timescales as you walk up the stairs of the Empire State Building. Now, in this way of thinking about things, everything from the Big Bang until today takes you to just about here, the 10th floor. We're about 10 to the 10 years from the beginning. And what I do is I take the audience from that point, and I step through the key markers in the far future of the universe to give you a feel for what will happen, and I can sort of take you through-

    9. SBSteven Bartlett1:58:51

       Please

    10. BGBrian Greene1:58:51

        ... a couple milestones, right? So again, here we are today-

    11. SBSteven Bartlett1:58:54

        Stop when it gets scary.

    12. BGBrian Greene1:58:55

        Yeah, well, it's scary the whole way. [laughs] You know, so here we are 10 to the 10 years from the beginning. If you just go up to here, 10 to the 11 years, what happens here is the sun will get bigger and bigger. It swells. It eats up the close planets, Mercury and Venus. It may swallow up the Earth too. We're not sure. But certainly, it will make life on Earth virtually impossible because it would be so hot on this planet. If you go up to the next floor above that, 10 to the 12 years from the beginning, what you find here is that the universe is expanding ever more quickly, driving the distant galaxies away faster than the speed of light, so we won't see them. So a future astronomer here looking out into the deep night sky will see only darkness. In the deep, deep night sky, everything will have drifted beyond the cosmic horizon.

    13. SBSteven Bartlett1:59:50

        Why will it be going faster than the speed of light?

    14. BGBrian Greene1:59:52

        Because we have found, surprisingly, that the expansion is speeding up.

    15. SBSteven Bartlett1:59:56

        And there's no limit to that.

    16. BGBrian Greene1:59:57

        There doesn't seem to be a limit. Now again, there's always assumptions in every prognostication assuming that what we measure and see today will persist. It's like what the AI people are assuming, that the growth that they see today will persist. Is that true? We don't know, but it's our best guess from the laws of physics that it will. If you then go up to about here, the, uh, 20th floor, something interesting happens. If the Earth is still here, if it wasn't swallowed up on the 11th floor by the swelling sun, the Earth is gonna spiral into the dead sun because it will lose energy through gravitational radiation. Ripples in the fabric of space will cause the orbit of the Earth to decay. We will crash in to the dead sun. That will be the end of the Earth, by about the 20th floor.

    17. SBSteven Bartlett2:00:47

        But the end of life itself took place-

    18. BGBrian Greene2:00:49

        Could easily have taken much earlier

    19. SBSteven Bartlett2:00:50

        ... on the 11th floor.

    20. BGBrian Greene2:00:51

        On the 11th floor. If we go up to about the 30th floor, what will happen here is that the stars themselves will spiral into the black hole at the center of most galaxies. So most galaxies have a black hole. We have one in the center of our Milky Way galaxy. And the stars themselves, much like the Earth will spiral into the sun, the stars will spiral into the black hole, which means there'll be only kind of black holes as the remaining macroscopic structure in the universe.

    21. SBSteven Bartlett2:01:25

        Has that happened elsewhere?

    22. BGBrian Greene2:01:26

        Oh, certainly. We see things that can spiral into black holes in, and certainly even in the center of our galaxy, there's evidence that there's activity there, and that activity, in part, is stars being ripped apart as they fall into a black hole. So this is pretty clear that this will happen.

    23. SBSteven Bartlett2:01:44

        Is this the end of all galaxies as they spiral into the black hole?

    24. BGBrian Greene2:01:47

        Yeah, so after 10 to the 30, 10 to the 35 years, it's hard to imagine that galaxies as we know them will persist. The stars will have burned out. I could have even mentioned another milestone. Around the 14th floor, almost all stars will have used up their nuclear fuel.

    25. SBSteven Bartlett2:02:06

        All of them-

    26. BGBrian Greene2:02:07

        Just about all of them will fade to black in the universe

    27. SBSteven Bartlett2:02:08

        ... all of them in the whole universe?

    28. BGBrian Greene2:02:10

        Yeah. Yeah.

    29. SBSteven Bartlett2:02:10

        So they'll be gone.

    30. BGBrian Greene2:02:10

        Or at least the observable universe. I can only really speak to the part that we have direct access to. Yeah. And so by the 30th floor, those, those d- Dark stars will spiral into black holes

Episode duration: 2:11:43