字幕表 動画を再生する 英語字幕をプリント >>NEIL DEGRASSE TYSON: Welcome back. This is the 17th Annual Isaac Asimov Panel Debate. And we’ve been going strong ever since the year 2000, when an idea surfaced in the hearts and minds of the family of Isaac Asimov, exploring a way for his memory to be preserved in the programs of this institution. And Isaac Asimov was a friend of the American Museum of Natural History. Much of the research for so many of the books that he wrote took place in and around the halls and in our libraries. And so perhaps there’s no more fitting tribute to him and to his memory, than to keep this celebration going. So, thank you for attending. We are also streaming live on the Internet. And I’m your host for this evening, Neil deGrasse Tyson. I’m the Frederick P. Rose director of the Hayden Planetarium. [applause] Just a couple of newsy notes. This year we sold out in three minutes. And it’s not a particularly sustainable model. So, we’re going to have top people looking at how to improve that next year. We don’t know how yet, but the least we can do is offer it live streamed on the Internet on amnh.org. So, I welcome everyone from the Internet universe, as well as the universe gathered here. Tonight’s topic is: Is the Universe a Computer Simulation? Yeah. [laughter] Do you want it to be a computer simulation? I mean, this topic is—we’re going to—you’ll see. We’ve got some highly thoughtful, talented, respected people to weigh in on this. I will introduce them individually, and then we will start the panel. By the way, unlike most debates you might have heard about or read about, where there’s point/counterpoint and an argument is presented and attacked, that’s not what’s going to happen here. We’re using the word debate loosely. Think of yourself as eavesdropping on scientists at a break-out room in a conference on this topic. So, we’ll all be sort of arguing with one another, and you’re listening in. That’s really what’s going on here. And you get to see how scientists think. You get to see how arguments are contested. You get to see how resolution arrives, if it arrives at all. So, afterwards we will have a brief time for question and answer before we adjourn before 9:00 Eastern time zone—Eastern daylight time. So, join me in welcoming my first panelist this evening. He is a professor of philosophy at New York University, where he’s also director of the Center for Mind, Brain and Consciousness, David Chalmers. David, come on out. [applause] >>DAVID CHALMERS: Hey. Looking forward to this. >>NEIL DEGRASSE TYSON: Thank you. Next we have a nuclear physicist, who’s a post-doctoral research associate at MIT up in Cambridge, Massachusetts. And let’s give a warm welcome to Zohreh Davoudi. Zohreh. [applause] Next, we have someone who is actually no stranger to this panel. This may be his third visit to it. In part, the topic of this year was selected because he brought it up a couple of years ago. And I said, man, we could do a whole subject on that alone. Let’s give a warm welcome back to James Sylvester Gates. [applause] Another non-first timer is professor of physics up at Harvard, a specialist in nuclear particle physics. Give a warm New York welcome to one of our own, a graduate of Stuyvesant High School, Lisa Randall. [applause] Did I do this out of order? No, we didn’t. Good. And last among the five—yeah, I did do it out of order. My bad. Yeah, sorry. You guys know where you need to sit. Talk among yourselves while I do this. There’s a friend and colleague, an astrophysicist, also from MIT, who’s done some deep thinking about this very subject and has even written a book on the topic. Let’s give a warm New York welcome to Max Tegmark. [applause] [technical difficulties] How about now? There we go. Oh, by the way, we are lit for live streaming. And the intensity of the lights on the stage is such that two of our panelists—I think they just want to look cool, but they said they need to wear sunglasses for this event. And that’s cool. Later on I might join you. I brought my pair with me as well. If I’m feeling cool I might do just that. So, Zohreh, I’d like to start with—no. who should I start with here? Yes, let me start with you, Zohreh. Could you tell me why this topic interests you? Just give a couple of minutes just as an introduction here. >>ZOHREH DAVOUDI: Sure. So, as Neil said, I’m a theoretical physicist. My interest is in nuclear physics. In fact, I got my PhD in 2014 from Institute of Nuclear Theory in University of Washington. And the research I was focused on there, and at the moment, is trying to use the knowledge of the laws of nature and, in particular, strong interactions to start from a bottom-up approach and try to see what comes out in a physical system. And that’s actually relevant to why I got interested in the simulation idea. And, in fact, by just watching the progress that researchers in this field of simulating a strong interactions have made in several past few years, we started to wonder how could we not think about the universe itself based on the laws that we’ve discovered not simulated. So, that the way that we actually simulate the universe, it might actually give us hints that the universe itself could be a numerical simulation. And then you would start thinking, well, let’s make assumption that if that scenario is the case, and if that simulation is actually—has similarities with what we do in our research and just drawing parallels between our algorithms and techniques that we use to simulate laws of nature, and making assumption that they are similar, then what can we actually conclude about the universe as a simulation. Can we actually make predictions for the signatures that we should go after and test? So, that’s that approach we took. And it was a fun idea and fun paper became of it with my collaborators Martin Savage and Silas Beane at the University of Washington. And that’s basically why I’m here. I’m trying to— >>NEIL DEGRASSE TYSON: So, the prospect of this being true didn’t freak you out at all? >>ZOHREH DAVOUDI: No, I think it’s a fun idea. >>NEIL DEGRASSE TYSON: Okay. Just it’s fun for you? >>ZOHREH DAVOUDI: Yes. >>NEIL DEGRASSE TYSON: Okay. Fine. So, Max, you’ve got a book on this, too, right? So, what’s going on with you? >>MAX TEGMARK: Yeah. Well, already as a kid I was always very fascinated by these very big questions about what’s really going on with this reality. I remember actually lying in this hammock I had put up between two apple trees back in Stockholm, Sweden when I was 13, reading Isaac Asimov actually. I’m very honored to get to be here. It really makes you think about these big, big questions. And the more I learned about later on as a physicist, the more struck I was that when you get deep down under the hood about how nature works, down to looking at all of you as just a bunch of quarks and electrons, the rules— >>NEIL DEGRASSE TYSON: And you, too. It’s not just us. Yeah. Looking at you as a quark, no, you would come under this category as well. >>MAX TEGMARK: Yes. I am a quark blob, too, I confess. But if you look at how these quarks move around, the rules are entirely mathematical as far as we can tell. And that makes me wonder, if I were a character in a computer game, who starting asking the same kind of big questions about my game world, I would also discover eventually that the rules seemed completely rigid and mathematical. I would just be discovering the computer program in which it was written. So, that kind of begs the question: How can I be sure that this mathematical reality isn’t actually some kind of game or simulation? >>NEIL DEGRASSE TYSON: So, you’ve analogized yourself to Super Mario in a—that’s who you are? >>MAX TEGMARK: I don’t know if that’s a good thing or a bad thing. >>NEIL DEGRASSE TYSON: So, Jim, I just remembered you started all of this a few years ago, in my mind at least, just triggering the idea that in your research you found things that forced you to consider the likelihood that somebody programmed us. Could you— >>JAMES GATES: Well, first of all, I would disagree with you. I’m not sure somebody programmed us, but that’s—you and I had a conversation where I pointed out that in my research I had found this very strange thing. Physicists, I like to say we all belong to a company called Equations-R-Us because that’s how we make our living, is by solving equations. And so I was just going through solving equations, and I was then driven to things that Max knows about, these things called error-correcting codes. Error-correcting codes are what make browsers work. So, why were they in the equations that I was studying about quarks and leptons and supersymmetry? And that’s what brought me to this very stark realization that I could no longer say that people like Max were crazy. >>MAX TEGMARK: Okay. [laughter] >>JAMES GATES: Or stated another way, if you study physics long enough, you, too, can become crazy. >>NEIL DEGRASSE TYSON: That’s a corollary to that idea. Yeah. >>JAMES GATES: And I’m also a science fiction fan like Max, who talked about his encounter with Asimov. I was reading at age eight, as opposed to 13, sir. >>MAX TEGMARK: I hang my head in shame. >>NEIL DEGRASSE TYSON: Snap. >>MAX TEGMARK: Got off to a slow start. >>JAMES GATES: I was reading at age eight a science fiction book by an author named Paul French. And some people in the audience might know that’s a pseudonym for Isaac Asimov. >>NEIL DEGRASSE TYSON: Oh. >>JAMES GATES: So, science fiction drove me into science in some sense. And then now in my 65th year of life, I find out I have to make friends with Max and people like that. >>NEIL DEGRASSE TYSON: So, Lisa, I kind of brought you on the panel because I knew you—I mean, you’re a rationalist in all this. And so I was expecting—I don’t know what to expect. I just needed to anchor this in somebody who I knew was not going there. So, where— >>LISA RANDALL: Yeah. So, actually—well, I can’t say I decided to be on the panel because I think I said what date is it, and they were like, “Thank you for agreeing to be on the panel.” But I have to say I’m curious not so much about the question of whether we’re a simulation because I think it’s only interesting insofar as there are ways to test it. And we can come back to that, I think, very much in terms of how the laws of physics operate and whether we can actually distinguish that. But I actually am very interested in why is so many people think it’s an interesting question. Like why is the audience here? Why is this panel here? Because really to first approximation we can’t really distinguish it. So, I think the interesting question is: Why do we feel compelled to want this to be true, or even think this could be true? And how do the laws of physics operate? And are there really ways that we could eventually test whether there is something that distinguishes just a true universe? But I have to just say if the inference is simulation, I don’t understand why it gave me a cold today. >>NEIL DEGRASSE TYSON: Okay. >>LISA RANDALL: So, my voice might go. But I also think sometimes some of the ridiculous things in the universe and think, really, why would that be part of the simulation? And I realized that if I was doing a simulation, I would definitely put those things in. So, there you go. >>NEIL DEGRASSE TYSON: Okay. Well, thank you for that. Now, we couldn’t have a panel without a philosopher. David, we needed some philosophical— >>DAVID CHALMERS: I know how you love philosophers, Neil. [laughter] >>NEIL DEGRASSE TYSON: I’m on record for some comments about philosophers that got him a little ticked off. Buy, anyhow. So, David, what do you—philosophers have been at this for a while, yourself included. So, how do you see all of this happening or fitting in to the worldview? >>DAVID CHALMERS: Well, philosophers like to ask the big questions about the world; the foundational questions. And this is one of them. Actually, I blame Isaac Asimov for all this, at least in my case. I got into thinking about these big questions when I was a kid. I read just about everything that Asimov was writing. Not just the science fiction, but the science fact, the history, the detective novels. I read multiple volumes of his autobiography. But throughout Asimov’s work, this was a guy that was just interested in the big questions about the nature of reality at all levels. And that, ultimately, drove me to think about questions about consciousness and the mind, which I could approach as a philosopher because philosophy allows you to step back and say what is the science here telling us. But this question about the simulation corresponds to another of the great questions of philosophy, which is basically how do we know anything about the external world at all [unintelligible 15:46] said how do you know you’re not being fooled by an evil genius into having an impression of this world around us? Even though none of it really exists. Well, the contemporary version of that question is: How do you know you’re not in a simulation like The Matrix? In which case, allegedly, none of this really exist. And, to me, that question is just extremely interesting because it seems nothing we could know could rule out the hypothesis that we’re in a simulation. But you also want to think about what follows. Some people think if we’re in a simulation, then none of this is real. I think if you adopt the kind of perspective which, say, Max was suggesting a second ago, where the universe is all mathematical or informational, this allows us to reorient our attitude to this question and say, okay, maybe we’re in a simulation. But if we are, all this is perfectly real because all the information is there in the simulation. All the math is there. All the structure is there in the simulation. So, I’d say, well, maybe we’re in a simulation. Maybe we’re not. But if we are, hey, it’s not so bad. >>NEIL DEGRASSE TYSON: If I do this, you feel that. >>DAVID CHALMERS: Yeah. >>NEIL DEGRASSE TYSON: Okay. So, that’s real. That was a real punch. Yeah. So, Zohreh, let me ask you, I see you coming to this almost from the most pragmatic side. You’ve done experiments with your colleagues. Or you’ve had hypotheses with your colleagues. Could you just detail for me where you landed in one of those papers that you guys published?