Pod Insights StarTalk Podcast Cosmic Queries – Living in a Simulation with Nick Bostrom About this episode Are we in a simulation? On this episode, Neil deGrasse Tyson and comic co-host Chuck Nice take a deep dive into simulation theory, consciousness, and free will with Oxford theorist Nick Bostrom. Is this The Matrix?
Transcript Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.
0:01 Neil deGrasse Tyson? Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk Cosmic Queries Edition. Neil deGrasse Tyson here, your personal astrophysicist. I got Chuck Nice with me, of course. Chuck, my-
0:24 Chuck Nice? What's up, Neil?
0:25 Neil deGrasse Tyson? -faithful co-host. You know, we need you for the Cosmic Queries so that you can mispronounce everyone's name.
0:33 Chuck Nice? Well, that's my purpose in life, Neil. I live to butcher names.
0:41 Neil deGrasse Tyson? Those poor questioners.
0:43 Speaker 02 How would you attack my name?
0:45 Chuck Nice? Oh, my goodness. So, Nick Bostrom? Is that what you- Is that how-
0:52 Speaker 02 It's-
0:52 Chuck Nice? That's pretty good.
0:54 Speaker 02 It's-
0:55 Chuck Nice? Is that all right?
0:56 Speaker 02 In Swedish, it would be Niklas Bostrom, but that was close.
1:00 Chuck Nice? All right. And listen, I'll take "close." As far as I'm concerned, names are like a game-
1:05 Neil deGrasse Tyson? Close is better than-
1:06 Chuck Nice? Yeah, that's like a game of horseshoes for me. "Close" is good enough.
1:12 Neil deGrasse Tyson? Good enough. So that was indeed Nick Bostrom chiming in. Nick, welcome to StarTalk. Dude, you started something that has got the whole world, you know, spinning in a tizzy for birthing the concern that we all live in a simulation. And let me just give a fast bio on you. You're a professor at University of Oxford in the Future of Humanity Institute.
1:42 Chuck Nice? Oh, that doesn't look very bright.
1:44 Neil deGrasse Tyson? You know, it doesn't look very bright.
1:48 Chuck Nice? Sorry. Sorry, Niklas. Not a lot of job security in that, buddy.
1:52 Neil deGrasse Tyson? No future for humanity.
1:55 Chuck Nice? Looking at the future of humanity, yo.
1:59 Neil deGrasse Tyson? So you think about artificial intelligence, the ethics of artificial intelligence, biosecurity, what have you, macro strategy? We'll ask you what that is in a moment. Just policy, ethics, foundational questions about-
2:18 Neil deGrasse Tyson? Serious challenges that civilization faces, not in the distant future, but in the very near future. I like the fact that you have a background in theoretical physics. So put you in the physics club here, that's good. Also computational neuroscience. We have some of those at my home institution at the American Museum of Natural History. That's quite the frontier as well. And you had a rather influential paper, research paper titled, "Are You Living in a Computer Simulation?" And for me also, I remembered your book, "Superintelligence", which all of these got people thinking, as any good philosopher should do, is to get people thinking.
3:01 Neil deGrasse Tyson? And so could you just start us off? Why do you think we might be living in a simulation?
3:09 Speaker 02 Well, I have this thing called the simulation argument, which doesn't actually prove that we're in a simulation, but it tries to show that at least one of three propositions is true.
3:20 Neil deGrasse Tyson? So let's, we want to hear your line of reasoning, which ought to be good, given your sort of logical background in this universe. So let's, let's hear what you've got.
3:29 Speaker 02 Well, I mean, you probably would be able to explain it better. But yeah, my story is that the simulation argument tries to show that one of three propositions is true. So let's, let's first look at what the conclusion is, and then we can see how we get there. So the conclusion is that either almost all civilizations at our current stage of technological development go extinct before they become technologically mature. So that's like one alternative, right? The second is that amongst civilizations that do become technologically mature, there is a very strong convergence. They all lose interest in creating a certain kind of computer simulation. I call them ancestor simulations. These would be
4:11 Speaker 02 Detailed simulations of people with the kind of experiences that their historical forebears had. So that's the second alternative. And then the third alternative is that we are almost certainly living in a computer simulation. So that's the kind of conclusion. Now, how does one get to that? Well, suppose that the first of these alternatives does not obtain. So that means it's not true that almost all civilizations at our stage failed to reach technological maturity. Some non-trivial fraction make it through, okay? Then let's suppose that the second alternative is also false. So amongst those who do become technologically mature, some non-trivial fraction remain interested in using some of the resources to create these kinds of ancestor simulations.
4:56 Speaker 02 Then you can show that the kind of computational resources a mature civilization would have would suffice to create millions and billions of detailed simulations, ancestor simulations, runs of human history. And so that if the first two alternatives are false, then there would be many, many more simulated versions of people with our kinds of experiences. Then there would be original, implemented in a basic physical reality, people with our experiences. And conditional on that, if almost all people with our experiences are simulated, we should think we are probably one of the simulated ones
5:40 Speaker 02 rather than one of the rare, non-simulated ones. So that means that if you reject the first two alternatives, you would then have to accept the third one. And then that shows that it's not the case that all three of them are false. So hence, at least one of them is true. So that's the structure.
5:57 Neil deGrasse Tyson? Why can't there be a fourth other truth? That no one gives a rat's ass about simulating anything, anywhere?
6:04 Speaker 02 Well, so that's the second, right? I mean, so if all of these technologically mature civilizations are completely uninterested in simulating...
6:13 Speaker 02 Then that would be possibility number two. But but note that for the second alternative to hold, it's not sufficient that most of them are not very interested. Because even if it were just a one percent of these mature civilizations that were even a little bit interested.
6:28 Neil deGrasse Tyson? It's a big number.
6:28 Speaker 02 They still could produce millions of them. And so that would have to be this extremely strong convergence, like almost all of them would completely have to lose any interest in doing this in order for the second alternative to be there.
6:40 Neil deGrasse Tyson? Okay, so so I have publicly mildly butchered your line of argument there. So let me first apologize. What I had been noting is that we do not have the power yet to create a perfect simulation of a world such as the one we're living in. And so I wasn't thinking that everyone would make these ancestor simulations, which we would be. And so an ancestor civilization in a in a cinematic a parallel would be a movie about Spartacus or Cleopatra.
7:23 Neil deGrasse Tyson? Just some something, a movie, which is modern technology, telling a story set in a time when they didn't have movies. Right, so that would be like an answer. I'm guessing that's what you mean by an ancestor simulation. And so so I was thinking that every simulation would ultimately be able to duplicate themselves as a natural evolutionary arc. If that's the case, then we would either be the original universe that hasn't yet simulated anybody yet, or we'd be sort of the last one simulated, still working our way towards the power of simulating ourselves, which would be slightly better odds, well, a lot better odds,
8:06 Neil deGrasse Tyson? than throwing a dart and landing in all the simulations that had enough power to create simulations of themselves.
8:14 Speaker 02 Yeah, well, I
8:15 Neil deGrasse Tyson? I think that makes sense.
8:16 Speaker 02 Well, so, so first of all, I don't claim that the only simulations that might be made are ancestor simulations. I mean, that, I mean, if you imagine you're a technologically mature civilizations, you might simulate all kinds of things like real histories as close as you can get, fantasy worlds, counterfactual histories, imaginary alien civilizations, I mean, you could, maybe there are like lots of all of these kinds of simulations. Um, the argument focuses on ancestor simulations just because that's the easiest way to get to the conclusion that one of these three is true. But it doesn't imply that there wouldn't be a lot of other simulations as well.
8:52 Neil deGrasse Tyson? Okay, so we, we have some data with our own history of cinema. And it's some very small percent of movies are set in a time before movies were invented, which I would, again, I would classify as sort of ancestor storytelling.
9:07 Speaker 02 Yeah, so I mean, I guess when we extrapolate to these technologically mature, presumably post-human civilizations. Well, first of all, I'm not sure how much we can infer from the kinds of movies we create to what types of simulations they would run. But let's suppose for the sake of the argument that the majority of simulations they run are of people in their contemporary society. So, I don't know, some super advanced space colonizing thing with super intelligences or whatnot. And that that's maybe the majority of what they do. But that they assign some, some smaller fraction of their computational resources to doing these ancestor simulations. So let's, let's assume that.
9:48 Speaker 02 Um, I still don't think that would defeat the simulation argument. Um, or indeed even the alternative that we are in a simulation. Because, um, we kind of already know that we are not one of the post-humans. I mean, you just look around, you don't see a lot of starships whizzing by outside your window. And we are not currently running any simulations ourselves. So we can kind of cross those out. Like all the actual post-humans, we know we're not one of those. And we also know we are not in a simulation of a post-human. That's not the world we experience. Then that leaves only, A, the people in original history at the human level of development, and also whatever ancestor simulations are at that level of development.
10:33 Speaker 02 And so my claim would then be that, you know, if the first two alternatives of the simulation argument are false, the simulated ones. At our current level of development would still vastly outnumber the original ones at our stage of development.
10:48 Chuck Nice? So what is the likelihood that, not likelihood, because that's the wrong word. Is it possible that it could just be the way that we create with our limited technology, what we feel are simulations of our lives, okay? And that's computer games and video games and things like that. Could it be that a civilization so advanced that they have the computational power to create all of this just for the hell of it? Just because, like, the same way we do it. We do it for entertainment. Could it just be that? Or is that just not a part of the philosophy?
11:25 Speaker 02 It could be. I mean, so the simulation argument itself is agnostic as to what the motivation would be of the simulators. And you could indeed imagine many possible motivations. One would be just entertainment, right? And you could imagine other, like, maybe some kind of research, like historically. Maybe it would be interesting to explore counterfactuals of history. Or you could imagine art projects, or you could imagine moral reasons for. I think we know rather little about the psychology and motivations of these hypothetical post-human civilizations and why they would make simulations.
12:02 Neil deGrasse Tyson? Okay, so Nick, I guess you're allowed to say all this, like, from your armchair. But at some point, somebody wants to walk into a lab and make a measurement that says, here's the evidence that supports Nick's argument. Is there such a...
12:21 Neil deGrasse Tyson? Anything we can look for? Is there a sign? Is there some experiment we can conduct to say, yep, we're not in charge of what's happening here. This is a simulation.
12:34 Speaker 02 There certainly is sort of empirical premises that flow into the simulation argument. And so evidence for against the truth of those assumptions.
12:44 Speaker 02 You know, would be relevant to evaluating the argument. So one empirical premise is that a technologically mature civilization would indeed have the capability of creating ancestor simulations, and indeed to create lots of them. And so the kinds of evidence that would be relevant for that is evidence, say, of the kinds of computational performance you could get from physically possible systems. We're not able to build them currently, but we can kind of do first principle modeling of different computational systems based on nanotechnology and so forth, and we can place lower bounds on the kind of compute power that they would unlock. So that would be one, like, element that would flow into this.
13:29 Speaker 02 And another would be some estimate of the computational cost of running an ancestor simulation. I think the largest part of that cost is the cost of simulating human brains at the sufficient level of detail that the simulation would be conscious. And we can obviously not precisely determine what the computational expense of simulating a human brain is, but we can place some upper bound on that. We have various views about what computational tasks the human brain is capable of performing. We know how many neurons there are, how many synapses, how often they fire, we can roughly estimate that. Now, it turns out that if you estimate the amount of compute power available, even if you make rather conservative assumptions about that, and then you make conservative
14:14 Speaker 02 assumptions about how much it takes to simulate one human brain, and therefore how much to simulate all of the human brains, you just multiply that by 100 billion or something to all of the human brains in history, there are a number of orders of magnitude gap between these two. So even if you are off a little bit in these estimates, it still seems like the argument holds. But so those would be empirical premises that we could, you know, theoretically obtain evidence against. Like if we discovered the human brain uses some kind of weird quantum computation that is a lot more expensive than that would point to. Then if in addition you want to conclude not just that one of these three alternative is true, which is all the simulation argument itself says, but if more specifically you want to conclude that we are in a simulation, that the third alternative is true, then
14:57 Speaker 02 there is an additional range of empirical questions that become relevant, like anything that gives you evidence against the first two.
15:05 Speaker 02 Or in favor of the first two would be the unrelevant evidence for evaluating the third, right? So if we discover that there is some kind of big risk, some doomsday mechanism that we can, ah, now we realize this, all sufficiently advanced civilizations will stumble on this new technology and destroy themselves. That would be argument against the simulation hypothesis, because it would make the first alternative more likely. So that, I think, is actually the main.
15:27 Neil deGrasse Tyson? That would be a really sad argument. But that'd be a really sad argument against it, because it would say, here's our proof we're not simulated. We're about to destroy ourselves.
15:36 Chuck Nice? We're gonna blow everything up.
15:38 Speaker 02 Yeah.
15:38 Chuck Nice? Now, Nick, let me ask you this. Let me ask you this, Nick. Is it possible that you are so smart that you are constantly high and you don't know it?
15:54 Speaker 02 I think in some more or less metaphorical sense, I think that's very likely to be true. If you, it's kind of the pessimistic meta induction, right? So if you look at all humans who have ever been alive, all eras going back in time, we can now see from our current vantage point, basically, they were all very wrong about some big thing. I mean, like, starting with simple physics, they thought Earth was in the center and then like, but basically, we can see, if we look back more than 100 years, we see that they all got a whole bunch of really core things wrong. And it would kind of maybe be a little bit presumptuous to think that now, finally, we've gotten all of these basic things, right?
16:35 Speaker 02 It seems more likely that if people 1,000 years from now look back at 2021, they will probably also see big, not just gaps in our understanding, but like, things we were fundamentally confused about. And so.
16:49 Neil deGrasse Tyson? Yeah, they'll laugh their ass off at everything we're talking about right now.
16:52 Speaker 02 Yeah, or, yeah, or Christ or Adad or whatever. So I do think we are, in a fundamental sense, very much in the dark about the really biggest picture.
17:02 Neil deGrasse Tyson? Well, we gotta take a quick break. And when we come back, we'll transition to our questions that we've solicited from our Patreon members. So we'll be right back on StarTalk.
17:21 Speaker 03 Hey, I'm Roy Hill Percival and I support StarTalk on Patreon. Bringing the universe down to Earth, this is StarTalk with Neil deGrasse Tyson.
17:38 Neil deGrasse Tyson? We're back, StarTalk. I've got the one and the only Nick Bostrom. I generally regard it as the person who birthed all of our sleepless nights wondering whether we are in a simulation, not only from his research papers but from his books on the subject. And he's a professor at the University of Oxford. And Chuck, what did we call it? What is the name of his thing here? The Future of Humanity Institute, which Chuck and I are pretty sure will be very short-lived, because there's no future for humanity at all. Just before we get to the questions that Chuck has collected, Nick, it's one thing
18:19 Neil deGrasse Tyson? to simulate all of the brains, I get that. But it's another thing, the fact that I can go into a garden and then look at a flower, or dig through the soils, and keep digging and reach the mantle of the Earth. Whoever's simulating us has to simulate not only what my brain is doing, but it has to simulate all the things my brain is experiencing. And that's not just for me. Someone else could dig that same hole and they should be finding the same thing. So isn't the total complexity of the world, doesn't that have to be part of this simulation? Even the fact that I, as an astrophysicist, look out to the edge of the universe, decoding the nature of the Big Bang and all time and space that followed
19:04 Neil deGrasse Tyson? it. So why just limit your estimates to the power of the human brain if everything and the unfolding of the great cosmic story has to also happen alongside it?
19:16 Speaker 02 Yeah, I think you do need some computation assigned to simulating relevant parts of the environment. I think the biggest part will be the brains, but certainly if you had to simulate the all of the environment
19:32 Speaker 02 at subatomic detail continuously, I mean like quantum simulation of the entire universe would be completely infeasible. If the simulators have anything comparable to the compute power that we could realize in this universe.
19:44 Chuck Nice? You know what, I'm gonna disagree. I'm sorry, I know you're a genius, but here's the deal. Here's why I'm gonna disagree, Nick, because when movie makers make movies, they do not render the detail in every single little thing. What they have... He didn't get there yet. That was the next thing he was gonna talk about. Aw, man. Now, see, you already thought of this. Like I said. Jesus Christ, here I am, here I am making a discovery, man!
20:19 Neil deGrasse Tyson? Okay, Chuck, okay, continue. Wait, Chuck, finish the point and then we'll pick it up there.
20:24 Chuck Nice? Both of you already knew where I was going, but the deal is this. If you actually create a background, that background will pretty much be the same for all the characters that are mapped onto that background. So that's all I would say.
20:38 Speaker 02 I mean, I think that's the key to understand this whole simulation argument stuff. That if you had to simulate all of the environment in subatomic detail continuously, it probably would be completely infeasible to do that. But I claim that's not needed. All you would need to do is to simulate enough of the parts that we are observing when we are observing them, that to the simulated creatures, it looks real and that they can't tell the difference. And that's a lot less.
21:01 Chuck Nice? All right, wait a minute, I just thought of something else in support.
21:04 Neil deGrasse Tyson? So what that would mean, Chuck, Chuck, wait, Chuck, what that would mean, whole sections of the Pacific Ocean, where there isn't a boat, right, then no one has, so it doesn't exist until someone has to then see it and process it.
21:20 Speaker 02 So procedural content generation, so we use it in our computer games today a lot. Like you often only render the parts that some character in the game are observing. And maybe you have some very coarse grain simulation of the whole thing continuously, but you may fill in details if and when is needed. So if like right now, I don't have any idea what the atoms in this desk in front of me are doing, right? But if I took in principle, an electron microscope or something, I could look and I better see atoms there, right?
21:49 Neil deGrasse Tyson? The program would know, programmer would know you're about to bring out an electron microscope.
21:53 Speaker 02 Right.
21:53 Neil deGrasse Tyson? So they could see that. The calculation right in the beam, right there.
21:57 Speaker 02 Right. And if, if necessary, I mean, they could even pause the simulation or edit it or erase memories if they really screwed it up. But yeah, I think the kind of, um, the, the, the kind of capability would need to even create anything resembling this kind of simulation is very advanced. And I think with that advanced capability would also come the ability to edit and to monitor human thoughts and intentions and then kind of be able to do this kind of procedural generation that even we do in our computer games today.
22:30 Chuck Nice? That could explain why, um, I've heard Neil say this, that we are terrible data takers. Like as human beings, we are awful at taking in information. Well, if I'm programming a simulation, I would certainly want to program the people in that simulation to be like that because that way I wouldn't have to program all this detail into stuff.
22:55 Neil deGrasse Tyson? It protects.
22:56 Chuck Nice? It protects the integrity of my simulation.
23:03 Speaker 02 Yeah. Although I think to be fair, I think the difference between one human and another from the point of view of the simulators, it's like, well, there is one ant. It's got a few more neurons, it's this genius ant, but I mean, we are, we are all like ants, I think. Uh, so I don't think the difference in cost is that big.
23:22 Chuck Nice? Uh, cool. Very cool.
23:24 Neil deGrasse Tyson? Uh, all right. All right, Chuck, bring up, bring on a question. Let's see.
23:27 Chuck Nice? All right, here we go. Let's, uh, let's jump into this. This is Dennis, uh, Ghislain and Dennis says this.
23:35 Neil deGrasse Tyson? What's the spell of that?
23:35 Chuck Nice? Uh, G H I S L A I N. I said Ghislain.
23:42 Neil deGrasse Tyson? It's probably Jislane.
23:44 Chuck Nice? Jislane.
23:45 Neil deGrasse Tyson? Okay.
23:45 Chuck Nice? Yeah.
23:46 Neil deGrasse Tyson? Jislane.
23:47 Chuck Nice? My minute would be Denis Jislane, okay.
23:53 Chuck Nice? Denis Jislane, we'd like to know.
23:58 Chuck Nice? He says, he says in his papers, Dr. Bostrom talks about post-human stage civilization. Could you please develop on that and situate it in, listen, uh, Kardashian scale? Now, I don't know what any of that means.
24:16 Neil deGrasse Tyson? Okay, I can tell what the Kardashian scale is.
24:18 Chuck Nice? What is the Kardashian scale?
24:19 Neil deGrasse Tyson? Yeah, when I lead off with that, and I'll hand the baton over to you, Nick. So the Kardashian scale is a scale of how much energy you have access to and can exploit.
24:31 Chuck Nice? Oh, okay.
24:32 Neil deGrasse Tyson? Okay, so I think there are five levels. So one of them is, um, do you have access to all of the energy sources in your host planet? And if you do, and you can exploit them, you're civilization level one. So that means you can go into a volcano and tap the energy, you can tap the volcano the way you tap a cake. You could use the energy in the crust of the earth that would otherwise make volcan- um, earthquakes. You can tap that and use that for your own means, uh, storm systems, this sort of thing. So a, a level two civilization would control all of the energy that comes from its host star.
25:12 Chuck Nice? Okay.
25:13 Neil deGrasse Tyson? Okay, that's way more energy than what is embedded in your planet. A level three civilization would control all the energy of your galaxy that you happen to live in.
25:24 Chuck Nice? The massive black hole at the center of the galaxy, you could use that?
25:27 Neil deGrasse Tyson? Yeah, oh, yeah, exactly, exactly. And you wield this, and the history of, of, of, of civilization reveals that the, the nations, or the nation-states that had the most power, power, political power, cultural power, were those that, that actually wielded the most energy per capita.
25:50 Neil deGrasse Tyson? In the world at that time. So when people say, "United States, we're such energy hogs. We use, you know, four times or five times the energy as anybody else." Well, that correlates with other measures of power that exist in it. So let's keep going. So one more, uh, this level four, level five. If you control all the energy of the universe and then, you know, you're indistinguishable from a god that anyone would have, uh, uh, suggested. Now, so what are we? We're digging fossil fuels out of the earth with
26:22 Chuck Nice? So we're, we're level point five. We're level point three.
26:26 Neil deGrasse Tyson? They don't know. We're level zero. Okay. We're level zero. Okay. So Nick, if there's a super intelligence, presumably they have better access to energy, especially the kind of energy you're talking about that might need this simulation. So have you thought about where a super intelligence might fit on the Kardashian scale?
26:45 Speaker 02 Yeah, I mean, I think that would be higher up just because at that level you would be able to run a lot more of these simulations.
26:55 Speaker 02 And so even if there were some simulations run by, I don't know, Kardashian scale one civilization, like with the Dyson sphere around their southern, that's all they did. You know, once the civilization expands beyond that, they could run billions of times more. And there would be plenty of time for them to expand beyond that. So you could imagine almost all simulations that are run are being run by civilizations that have reached the limits of whatever space they have to expand into. That, that would presumably be Kardashian four or something, unless the universe is so crowded that each one only manages to, to get the sort of galactic level volume before it bumps up against its neighbors.
27:36 Neil deGrasse Tyson? Yeah, that's a good point because you can only have one galactic Kardashian scale civilization. Because anyone else who wants it, too bad, we're using all the energy. It's like, uh, in, in the United States right now, there's fights over the Colorado River basin. Because it's a water source, that, that river flows through multiple states. And each state has a pact with the other state, how much water they're supposed to use. And there, and there'll be future fights on access to this one source of fresh water. And so that's an interesting point. You can't have a universe filled. With high Kardashian level civilization because they would implode rapidly. It seems to be.
28:15 Chuck Nice? And what level is Death Star? What, what, what level is Death Star on the Kardashian scale?
28:20 Neil deGrasse Tyson? Oh, well, in, in, in Star Wars Episode VII, it controlled the energy of a star. So that would be, I guess, level two.
28:28 Chuck Nice? That's only level two. Wow. Awesome. Okay. Here we go. Let's, uh, let's jump right back in here.
28:34 Neil deGrasse Tyson? By the way, in Star Trek, the Borg were, that's a super intelligence that, that was cosmic in its influence. And so that would be a even, even higher here.
28:48 Chuck Nice? Right, yeah.
28:49 Neil deGrasse Tyson? Just to put that in context.
28:50 Chuck Nice? That's cool.
28:51 Neil deGrasse Tyson? So Chuck, give me another one.
28:52 Chuck Nice? Okay, this is William D A. Uh, quite easy. Nothing but letters. Here we go. He says, where do you stand on the concept of consciousness? And where do you draw the line? Would a simulated reality change your definition of what possesses consciousness?
29:14 Neil deGrasse Tyson? I like that. So Nick, is panpsychism, I presume that means that somehow consciousness is a shared entity? That we all participate in as one?
29:25 Speaker 02 Panpsychism, I mean, there are different sort of definitions, but it's broadly the view that everything is conscious.
29:30 Chuck Nice? Oh, wow.
29:31 Neil deGrasse Tyson? And, and so how do you, how do you put consciousness in? Is that a natural outflow of a sufficiently complex computer simulation of the brain?
29:42 Speaker 02 That would be my sort of default assumption. Yeah, yeah. I mean, I think for the simulation argument, you could kind of plug in whatever your favorite theory of consciousness is, and most of them would work.
29:53 Speaker 02 There might be some theories of consciousness which would not work. The simulation argument, one of its assumptions is what I call the substrate independence thesis, which is just the idea that in principle you could implement consciousness, not just on
30:11 Speaker 02 You know, carbon-based biological structures, but on any suitable computational structure. That what makes us conscious is not that we're made of carbon, but that our brains perform a certain type of computation.
30:23 Chuck Nice? Whoa. Holy crap. Wait a minute, so.
30:27 Neil deGrasse Tyson? Yeah, Max Tegmark has written on that very subject.
30:30 Chuck Nice? Yeah, your buddy Max.
30:31 Neil deGrasse Tyson? He's a friend of StarTalks.
30:32 Chuck Nice? And his thing is like, the entire universe is made of math because it goes down to particles and these particles have spin and, you know, so you can assign a value to them.
30:43 Neil deGrasse Tyson? Mathematically constructed entities. Yeah, there's good overlap there. Yeah, yeah.
30:49 Speaker 02 But as to where to draw the line, like, I don't really have a very good account of exactly, so I mean, I think humans are conscious and rocks are not conscious, but like exactly where, sort of in the hierarchy, that we would be caught up, I'm not sure. Or I'm not sure either that there is a sharp line there, it might more be that there is kind of diminishing or more and more strained senses in which lower order organisms have some kind of consciousness and it kind of fades out rather than there being a sharp threshold is what I would guess, but.
31:21 Chuck Nice? Now, all I can think about is a conscious rock. I just love the idea.
31:26 Neil deGrasse Tyson? So here's, here's what I wonder, Nick. I just have a, a not deeply thought out hypothesis that having thoughts such as we do, that are incomplete and that we wonder and we don't have good memory of things, we make stuff up, the fact that it's not perfect, we interpret as consciousness. Because if it were perfect, it's just data and our brain is a storage disk that occasionally puts information together with a new result. But the fact that we, we can sit there and say, oh, I feel this and I don't, and it's
32:05 Neil deGrasse Tyson? mostly how we reckon our, with our ignorance of our environment, even when we probe it for knowledge. I'm just putting it out.
32:14 Speaker 02 Yeah, well, I mean, I guess first of all, you could have a lot of artificial, even simple systems that would be imperfect in various ways. You could have some faulty hard drives that. Randomly erase various things. Um, you can also have kind of compressed representations. That's what you have to do if you're trying to do anything with AI is there's a lot of data coming in and you have to extract some important features based on that and throw the rest away.
32:42 Neil deGrasse Tyson? Wait, Chuck, what Nick just said, I can't stop thinking about it. So Chuck, every time you and I forget something, the aliens hard drive messed up.
32:55 Chuck Nice? So every time you go, what did I come upstairs for?
33:02 Neil deGrasse Tyson? It's a read, write error, an I/O error in the programmer's disk.
33:09 Speaker 02 Well, so I don't, I don't think so. No, I was just exploring your account of consciousness. That somehow what's necessary or sufficient for consciousness is that there is some kind of faulty or limited information processing.
33:21 Neil deGrasse Tyson? Right.
33:22 Speaker 02 And so I was beginning to.
33:22 Neil deGrasse Tyson? Otherwise, it's a perfect computer.
33:24 Speaker 02 Well, um, I'm saying that computers are also imperfect in certain ways. And um, I'm not sure that the closer you get to perfection, that you would lose consciousness. I'm thinking anything, it might go the other way around, that you might become more conscious if you want more. But um, yeah, you might have to, if you wanted to sort of elaborate on that, you might want to try to say like, which types of imperfection are the ones that are supposedly making a system conscious? Um, and maybe, maybe exploring that line of thought further, maybe you would get to something that would be uh, some kind of plausible account of consciousness, I'm not sure.
34:02 Neil deGrasse Tyson? Oh, wow. Yeah, in the film, in the film I, Robot, forgive me for not having read the original series of short stories, but in, by Isaac Asimov, but in the film, they hypothesize what could account for free will in a programmed robot. And they were describing how many generations of operating systems. Are layered on top of one another and there's always these dangling parts that, you know, you don't always clean it up after because it's, evolution is like this too. They're dangling parts that worked at some point, now you don't need them, or that they could get in the way, or they can end up killing you, but programmatically, there
34:41 Neil deGrasse Tyson? could be lines of code that have long lost their utility, but could manifest under certain combinations of stimuli that look like the robot just thought of a new idea. And I was intrigued by that suggestion when I heard it in the film, that that could be the way you end up with what we call consciousness. But anyway, we gotta take another break. When we come back for the third and final segment, we're gonna go through a lightning round with our questions, and it's Nick Bostrum, just schooling us on whether or not we're in a simulation, and spoiler alert, it sounds like we kinda are.
35:23 Neil deGrasse Tyson? It sounds like, yeah, okay, when StarTalk returns.
35:40 Neil deGrasse Tyson? We're back, StarTalk. I've got Nick Bostrom in the house. Actually, he's in the UK right now, but he's in our Zoom house, and we're talking about the simulation hypothesis, and which he's largely started, okay? And so we blame him for all of our lost sleep at night. At least, Nick, I blame you, if no one else does. So Nick, the simulation hypothesis requires that every simulation has computers, right? Why is that an obvious thing? In fact, we've only had computers for like half a century, and we've been human for a couple hundred thousand years in our current form. Why should it be inevitable that a computer is the thing that gets invented that then
36:25 Neil deGrasse Tyson? people want to simulate on?
36:26 Speaker 02 I mean, I don't know that it is inevitable. Maybe there are a lot of humanoid species that never developed computers. I don't know. I mean, it suffices that some civilizations do develop computers, and then more advanced computers. Of the type we can already see are physically possible, although we cannot build. But certainly it's consistent with a lot of civilizations failing to reach even our stage of development. I mean, I think if you're asking about inevitability, even if it's not relevant for the simulation argument, it's kind of interesting. Like, you want, I guess, to find what point in time, if it's inevitable, like, it seems
37:08 Speaker 02 like the further back you go, if you sort of reran evolution from that point, the less likely that you would get something similar to what we have today. If you started with just bacteria, like, and who knows, maybe the chances would be very small, perhaps, that you would get an intelligent technological species. But if you started like 50,000 years ago, then, I mean, my guess would be we were already pretty well underway, and it was just a matter of time.
37:32 Neil deGrasse Tyson? Oh, that's an interesting, interesting point. Okay. Because the contingencies of evolution, right, it would take, in fact, if the asteroid didn't hit 65 million years ago, the dinosaurs would be here and we wouldn't, for sure. You take it late enough, Nick, that's a good argument. Start it 50, 100,000 years ago, it's, I'm good with that. We surely, there'd be some evolutionary path. And just for those who are ET fans, consider that we all would judge the Roman Empire to be an intelligent civilization, yet aliens trying to communicate with them with radio waves would conclude that there's no technology on Earth. Right?
38:14 Neil deGrasse Tyson? So we spent a lot of time being smart, but without the technology. And so that's the real question. How much longer do we have technology before we exterminate ourselves? But anyhow, Chuck, this is Cosmic Queries, bring it on. And Nick, we're gonna try to bang out a whole lot in this, in this third and final segment, so let's try to keep the answers tight.
38:36 Speaker 02 All right, bring it on.
38:37 Chuck Nice? All right, this is Dylan and Gordon Vu, gonna mash up their questions. Hello, everyone, from Albuquerque, New Mexico. I'm a senior in high school, and this question has been bugging me forever. Do we have free will, or is everything set in stone? Are we living a predetermined life if we are in a simulation? And then Gordon Vu says on top of that, if we manage to prove that we are living in a simulation, does that mean there is or is not a God? Thank you. Wow, talking about some philosophical, big, big, big-gun questions.
39:10 Neil deGrasse Tyson? Theological, philosophical. So Nick, I love those questions.
39:13 Speaker 02 Well, yeah, well, I mean, on the latter, I think it wouldn't prove or disprove God. I think it's an independent question whether we are in a simulation versus whether God exists. So I don't see any necessary connection there. On the free will, I think we would have as much free will in the simulation as we would without the simulation. I'm a compatibilist myself, so I think that even if we are living in a deterministic physical universe, that that would be consistent with us having, in the relevant sense, free will.
39:50 Speaker 02 But you might have a different view on the metaphysics of free will, but I don't think the fact that we would be in a simulation would necessarily change that.
39:58 Neil deGrasse Tyson? Would that mean that the programmers of that simulation would program into our brains a perception of free will, even if they know the outcome in advance at every moment?
40:10 Speaker 02 I don't think that we need to especially program that in. I mean, for the same reasons, we, if we are not in a simulation, would have this notion of free will. People in a simulation would presumably develop that for the same kind of reasons. I mean, it connects, obviously, to holding people accountable for certain things they do. I mean, if you stumble into somebody and bump them, we say, "Well, you're excused because you didn't intend it." But if you go and punch them and achieve the same boost, then you will be held accountable because that's something you did of your own free will. And so, and we make choices that we have to actually internally come up on a certain decision. So all of those things would hold equally true for people in a simulation as people outside a simulation, right?
40:55 Speaker 02 So if you have this view of free will, there wouldn't really be a difference, I think.
41:01 Chuck Nice? Interesting, okay.
41:02 Neil deGrasse Tyson? Why can't just the programmers be indistinguishable from God? If they have power over everything?
41:07 Speaker 02 Sure, yeah. I mean, depending on what you make into the concept of a God, yeah. In many ways, that would be analogous to how some people have traditionally conceived of God, right? In the sense that they would kind of have created our world. Although they wouldn't have created the whole world, just the parts that we see. They would presumably maybe not be omniscient, but they would know a lot. And they would not be omnipotent. They would themselves be subject to the physical constraints operating at their level of reality, but they could intervene in our reality, including in ways that contravene the laws of physics that we perceive.
41:47 Neil deGrasse Tyson? And thereby produce miracles.
41:49 Speaker 02 Yeah, but things that appear to us in this simulation as miracles. So in one sense, there is a kind of structurally similar relationship. On the other hand, they would be subject to all these, they would presumably be finite and subject to all these kind of limitations and constraints. And in that sense, kind of being infinitely far removed from a lot of the traditional conceptions of God, which is like a literally infinite and omnipotent and omniscient being. So I think that whatever the truth is about the simulation hypothesis, it wouldn't settle the question of whether there is this kind of more traditionally conceived, literally infinite God.
42:25 Chuck Nice? Okay, there you go.
42:26 Neil deGrasse Tyson? Perfect, all right. Okay Chuck, keep it going.
42:28 Chuck Nice? Frederick Johansson wants to know, is general AI really a question about hardware and processing speed? If it was, would a computer today be able to simulate a few seconds of AI like it had a thousand years to process?
42:45 Speaker 02 Yeah, it's a good question. I think compute is...
42:54 Speaker 02 A very important factor in driving AI progress over the last eight years or so with the whole deep learning revolution. I think it's maybe two thirds of the progress we've seen is due to we are applying more compute and then maybe one third is algorithmic progress. Even if it were all compute, it doesn't necessarily follow that we would be able to with our current compute run at least a small fraction of a human level mind. Because there are two things you need the compute for. One is to run the AI, right? Like to actually have it do, but you also need to train up the neural network that becomes the AI. So if you don't have enough compute to do the full training run,
43:37 Speaker 02 you might not even be able to develop the system, which then if run would constitute some kind of human equivalent level AGI.
43:45 Neil deGrasse Tyson? Got it. Right, because the calculation of the decision is not made in a vacuum. It's been completely preloaded with the world's life experience to whatever is sitting right behind that one decision. Is that a fair way to think about this?
44:00 Speaker 02 So for humans to arrive at some sort of normal adult level of performance, we need 20 years or 15 years to kind of grow up and learn. And our current neural networks are similar in that, although they are probably less efficient in learning, so they might need instead of 15 years of experience, maybe they need like a thousand years equivalent. But you still need a lot of compute just to be able to complete something analogous to like a human maturation process. So even if we had enough compute to run an AGI, a human level AI, we might not have enough compute to sort of create it.
44:39 Speaker 02 I think also that in addition to more compute, we also need some additional algorithmic insights. But it's not all or nothing, like the better the algorithms, the less compute you need to achieve this result. And right now, the amount of compute you need would be like way more than we can currently afford. And then it comes down as we make algorithmic progress. At the same time as our computers become faster, at some point these lines will intersect.
45:03 Neil deGrasse Tyson? You just made a point embarrassingly clear that humans require like a fourth of our lives just to function as participating humans in civilization. That's embarrassing, but true. Right, right. No one trusts your decisions you make until you're at least 20. And even then, for some people.
45:26 Speaker 02 Yeah, I mean.
45:27 Neil deGrasse Tyson? The brains are really not working even after.
45:30 Speaker 02 As a kind of collective, we have just kind of barely, you know, uh, intelligence to create a technological civilization. I think we look like we're right on the cusp of that. And it's not so surprising, maybe because like, if you imagine our ancestors had a lot less abstract reasoning ability and it gradually improved over biological timescales, right? And then as soon as we became capable of creating a technological civilization, then we pretty much did it or after, you know, 10,000 years or something. So, so we should kind of maybe expect that we are at the lower end of what is needed to do this at all. And that maybe explains some of what we see in the world, that we're kind of stumbling our way.
46:11 Neil deGrasse Tyson? A lot of what we see in the world, yes, yes. All right, Chuck, give me more, more. We got a few minutes left.
46:16 Chuck Nice? Skylar Gravat says, if this is a simulation, why are the people running the simulation so patient? The universe is estimated to be 13 point something billion years old and they waited almost 10 billion years to simulate life.
46:38 Speaker 02 Well, so first, uh, there is no particular reason to think that those 10 million years were simulated. You don't need to do it from the Big Bang onwards. You could start the simulation from a later point.
46:50 Neil deGrasse Tyson? You'd embed the simulation with evidence that that simulation scientist would then interpret as an old universe.
46:56 Speaker 02 Yeah.
46:56 Neil deGrasse Tyson? But it's all just fake.
46:58 Speaker 02 I mean, you probably don't want to sit through like 10 billion years of just gas clouds congealing like that would be a pretty
47:04 Chuck Nice? That's kind of boring, right? Yeah.
47:07 Speaker 02 But even even when you get into the, say they were interested like in all of human history, for the sake of the argument, that that's 10,000 years ago onward. Like, it doesn't mean that for them it would take 10,000 years to do this. They could run the simulation at a higher speed, like maybe, you know, one minute of their time could simulate a thousand years. It depends on how fast the computer is that you run the simulation on.
47:33 Chuck Nice? Gotcha. Wow.
47:35 Neil deGrasse Tyson? Right, so when we had a great revelation when computing power was adopted by astrophysicists in the 1970s, we were early out of the box on this, there were these galaxies in the universe that were kind of funky looking, and we made catalogs called peculiar galaxies. We didn't, you know, maybe just thought galaxies were made that way. Only after we were able to simulate the collision of two galaxies did we realize that this is like the crash scene leftovers of what happens when galaxies collide, and we simulate a billion years in a matter of minutes. And in so doing, we were able to populate the entire catalog
48:15 Neil deGrasse Tyson? of galaxy parts and nasty twisted looking galaxy forms, simply by seeing what happens when they collide and speeding up the time to do so. That's just a little aside.
48:26 Chuck Nice? Wow. Are you prescient or what? This is Nathaniel Mitchell, who says, "If we could ever simulate an exact replica of our universe, down to the spin on the components of quantum particles, could we speed it up and then use it to predict our future, as we now do with simulations for climate and otherwise, but yet on a cosmic scale?"
48:50 Speaker 02 Well, so that kind of thing wouldn't fit into our universe, like a computer that simulated all of our universe.
48:56 Chuck Nice? Okay.
48:57 Speaker 02 It wouldn't be possible to build that in our universe.
49:02 Neil deGrasse Tyson? Oh, that's a philosophical challenge. That's like saying, how detailed do you want your map to be? If you have a map the size of the UK, then it'd have all the detail of the actual island, but then you could just use the island.
49:19 Chuck Nice? You don't need that.
49:20 Speaker 02 Yeah, it would be like that. So, yeah, I mean, so, and yeah, I think it would be very infuseable to simulate our world at the level of, you know, quantum properties. At least if the simulator's universe looked anything like our universe. But maybe the physics at their level of reality is different. I mean, maybe they have more, maybe it's possible to build more powerful computers. You could even imagine hyper computation being possible in some other kind of physics, so that they could run literally infinite computations, and then maybe they could simulate a world like ours at full quantum detail. But that...
49:56 Neil deGrasse Tyson? And then run it forward and watch the future.
49:58 Speaker 02 But, I mean, from our point of view, it would... Presumably not make much difference whether they did it that way or the much cheaper way that would only render things at a sufficient level to be convincing to the people inside. And in fact, even if you imagine that there were some simulators that could do this at full quantum detail, it would cost them so much more compute that it would still likely be the case that almost all simulations would run in the more efficient way, that would only simulate things at the coarsest grade. So even if there were some fully full grain simulations, we would probably be in one of the other ones because that would be a lot cheaper. And so you could create orders of magnitude more of them.
50:42 Neil deGrasse Tyson? And how much of this relates to the fact that it's hard for something to understand itself? Like, can the brain, the human brain actually come to understand the human brain? Is that, or do you need a higher intelligence than the human brain to then study the human brain as a thing outside of itself?
51:00 Speaker 02 Understanding is a matter of degree, right? We understand a bit about ourselves now, we could understand more. I mean, obviously, you couldn't have a full simulation of all the details in the human brain stowed away in a part of the human brain, right? But that's the map of the UK, that would be as big as the UK, yeah, if you wanted all the details.
51:20 Chuck Nice? I've been to paradise, but I've never been to me.
51:24 Neil deGrasse Tyson? Chuck, thank you, Chuck. So we gotta land this plane. Let me just offer my best evidence for why I think we live in a simulation. And I'm just gonna go public on this. I think right when civilization is kinda going smooth, then something happens, okay? A politician rises up, there's a war, there's a world war, there's tsunamis. And I think that the aliens programmed that in for their own entertainment. Because that's what we did in the sim, in the sim games. In SimCity, where you're mayor of a city and everything's going fine.
52:08 Neil deGrasse Tyson? Unannounced Godzilla trounces through your city. And now you have to deal with it, the fire and the police and to rebuild the schools. And that's the programmer sending that in without telling you that's going to happen. I think all of the troubles we have in the world is evidence that the programmers need entertainment. Yeah, well, Nick, like I said, we got to land this plane. Thank you for coming out to StarTalk. This conversation was long overdue. I wanted to get you a few years ago, but you were in high demand and you still are for sure. But if any of us discovers something like a, we part the curtain and we see like a CPU there that when it was supposed to be a couch, I'll call you up.
52:51 Speaker 02 Well, if anybody viewing that does that, contact Neil rather than me. I don't need more.
53:00 Neil deGrasse Tyson? For sure. All right. It's been a delight, Nick. And is Superintelligence the book you would have people sort of check out in terms of the foundations of this thinking?
53:10 Speaker 02 Yeah, well, not specifically on the simulation argument. There, the article is online. Just Google it, simulation argument, you'll find it. But if you want to read a book about the future of AI and stuff, then Superintelligence would be the one I would point to.
53:24 Neil deGrasse Tyson? Excellent, excellent. All right, good. All right, Nick, again, thanks for joining us.
53:29 Speaker 02 I'm glad we could do it finally.
53:30 Neil deGrasse Tyson? Yeah, finally, this Cosmic Queries episode. I'm Neil deGrasse Tyson, your personal astrophysicist. As always, keep looking up.
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