property house logo

>>neil degrasse tyson: welcome back. thisis the 17th annual isaac asimov panel debate. and we’ve been going strong ever since theyear 2000, when an idea surfaced in the hearts and mindsof the family of isaac asimov, exploring a way for his memory to be preserved in the programs ofthis institution. and isaac asimov was a friend of the american museum of natural history. much of the research for so many of the booksthat he wrote took place in and around the halls and in our libraries. and so perhapsthere’s no more fitting tribute to him and to his memory, than tokeep 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. rosedirector of the hayden planetarium. [applause] just a couple of newsy notes. this year we sold out in three minutes. andit’s not a particularly sustainable model. so, we’re going to have top people lookingat how to improve that next year. we don’t know how yet, but the least wecan do is offer it live streamed on the internet on amnh.org. so, i welcome everyone

from the internet universe, as well as theuniverse gathered here. tonight’s topic is: is the universe a computersimulation? yeah. [laughter] do you want it to be a computer simulation? i mean, this topic is—we’re going to—you’llsee. we’ve got some highly thoughtful, talented, respected people to weigh in on this. i willintroduce them individually, and then we will start the panel. by the way, unlike most debates you mighthave heard about or read about, where there’s

point/counterpoint and an argument is presentedand 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 conferenceon this topic. so, we’ll all be sort of arguing with one another, and you’re listeningin. that’s really what’s going on here. and you get to see how scientists think. youget to see how arguments are contested. you get to see how resolution arrives, ifit arrives at all. so, afterwards we will have a brief time forquestion and answer before we adjourn before 9:00 eastern time zone—eastern daylighttime.

so, join me in welcoming my first panelistthis evening. he is a professor of philosophy at new york university, where he’s alsodirector of the center for mind, brain and consciousness, david chalmers. david, comeon out. >>david chalmers: hey. looking forward tothis. >>neil degrasse tyson: thank you. next wehave a nuclear physicist, who’s a post-doctoral research associate at mit up in cambridge, massachusetts. and let’sgive a warm welcome to zohreh davoudi. zohreh. next, we have someone who is actually no strangerto 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 coupleof years ago. and i said, man, we could do a whole subject on that alone. let’s give a warm welcome back to jamessylvester gates. another non-first timer is professor of physicsup 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, lisarandall. did i do this out of order? no, we didn’t.good. and last among the five—yeah, i did do itout of order. my bad. yeah, sorry. you guys

know where you need to sit. talk among yourselveswhile i do this. there’s a friend and colleague, an astrophysicist,also from mit, who’s done some deep thinking about thisvery subject and has even written a book on the topic. let’s give a warm new york welcome to maxtegmark. [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 wantto 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 interestsyou? 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, andat the moment, is trying to use the knowledge of the laws of nature and, in particular, strong interactions to startfrom a bottom-up approach and try to see what comes out in a physical system. and that’s actually relevant to why i gotinterested in the simulation idea. and, in fact, by just watching the progress that researchersin this field of simulating a strong interactions

have made in several past few years, we started to wonder how could we not thinkabout the universe itself based on the laws that we’ve discovered not simulated. so, that the way that we actually simulatethe universe, it might actually give us hints that the universe itself could be a numericalsimulation. and then you would start thinking, well, let’s makeassumption that if that scenario is the case, and if that simulation is actually—has similaritieswith what we do in our research and just drawing parallels between our algorithmsand techniques that we use to simulate laws of nature, and making assumption that theyare similar,

then what can we actually conclude about theuniverse as a simulation. can we actually make predictions for the signaturesthat we should go after and test? so, that’s that approach we took. and itwas a fun idea and fun paper became of it with my collaborators martin savage and silasbeane at the university of washington. and that’s basically why i’m here. i’mtrying to— >>neil degrasse tyson: so, the prospect ofthis being true didn’t freak you out at all? >>zohreh davoudi: no, i think it’s a funidea. >>neil degrasse tyson: okay. just it’s funfor 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 kidi 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 betweentwo 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 iwas that when you get deep down under the hoodabout 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’snot just us. yeah. looking at you as a quark, no, you would comeunder 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 questionsabout my game world, i would also discover eventually that therules seemed completely rigid and mathematical. i would just be discovering the computer programin which it was written. so, that kind of begs the question: how cani be sure that this mathematical reality isn’t actually some kind of game or simulation? >>neil degrasse tyson: so, you’ve analogizedyourself to super mario in a—that’s who you are? >>max tegmark: i don’t know if that’sa good thing or a bad thing. >>neil degrasse tyson: so, jim, i just rememberedyou started all of this a few years ago, in

my mind at least, just triggering the idea that in your researchyou found things that forced you to consider the likelihood that somebody programmed us.could you— >>james gates: well, first of all, i woulddisagree with you. i’m not sure somebody programmed us, but that’s—you and i had a conversationwhere 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, isby solving equations. and so i was just going

through solving equations, and i was thendriven 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 thati was studying about quarks and leptons and supersymmetry? and that’s what brought me to this verystark realization that i could no longer say that people like maxwere crazy. >>max tegmark: okay. >>james gates: or stated another way, if youstudy physics long enough, you, too, can become crazy.

>>neil degrasse tyson: that’s a corollaryto that idea. yeah. >>james gates: and i’m also a science fictionfan like max, who talked about his encounter with asimov. i was reading at age eight, as opposed to13, 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 eighta science fiction book by an author named paul french. and some people in the audiencemight know

that’s a pseudonym for isaac asimov. >>neil degrasse tyson: oh. >>james gates: so, science fiction drove meinto science in some sense. and then now in my 65th year of life, i find out i have tomake friends with max and people like that. >>neil degrasse tyson: so, lisa, i kind ofbrought you on the panel because i knew you—i mean, you’re a rationalist in allthis. and so i was expecting—i don’t know what to expect. i just needed to anchor this in somebody whoi 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, andthey were like, “thank you for agreeing to be on the panel.” but i have to say i’m curious not so muchabout 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, verymuch 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 interestingquestion. like why is the audience here? why is this panel here?

because really to first approximation we can’treally distinguish it. so, i think the interesting question is: whydo we feel compelled to want this to be true, or even think thiscould be true? and how do the laws of physics operate? and are there really ways that wecould eventually test whether there is something that distinguishesjust a true universe? but i have to just say if the inference issimulation, i don’t understand why it gave me a cold today. >>neil degrasse tyson: okay. >>lisa randall: so, my voice might go. buti 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 youfor that. now, we couldn’t have a panel without a philosopher. david, we needed somephilosophical— >>david chalmers: i know how you love philosophers,neil. >>neil degrasse tyson: i’m on record forsome comments about philosophers that got him a little ticked off. buy, anyhow. so, david, what do you—philosophershave 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 liketo 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 mycase. i got into thinking about these big questionswhen i was a kid. i read just about everything that asimov was writing. not just the sciencefiction, but the science fact, the history, the detective novels. i read multiple volumes of his autobiography. but throughout asimov’swork, this was a guy that was just interested

in the big questions about the nature of realityat all levels. and that, ultimately, drove me to think about questions about consciousnessand the mind, which i could approach as a philosopher because philosophy allows you to step backand say what is the science here telling us. but this question about the simulation correspondsto another of the great questions of philosophy, which is basically how do we know anything about the external world at all [unintelligible15:46] said how do you know you’re not being fooled by an evil genius into having an impression of this world aroundus? even though none of it really exists.

well, the contemporary version of that questionis: 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, thatquestion is just extremely interesting because it seems nothing we could know could rule out the hypothesisthat 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, wherethe 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 thesimulation. all the math is there. all the structure isthere 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 feelthat. >>david chalmers: yeah.

>>neil degrasse tyson: okay. so, that’sreal. that was a real punch. yeah. so, zohreh, let me ask you, i see you comingto this almost from the most pragmatic side. you’ve done experiments with your colleagues.or you’ve had hypotheses with your colleagues. could youjust detail for me where you landed in one of those papers that you guys published? >>zohreh davoudi: sure. so, what we did isnot actually doing the experiment. we proposed that experiments could go and look for the signs of possible underlyingsimulation for the universe. and the reason we thought about this, as isaid, is because we’ve been simulating strong

interactions, which means that instead of just looking at the larger structures,we’d start from the underlying degrees of freedom of our theory, the quark, gluons, and that we understand. and there are verysimple laws governing the interactions among these particles. however, when you think about all these complexsystems of atomic nuclei and larger systems in theuniverse, the ordinary matter in our universe, it all emerges from those simple, fundamental building blocks and theseinteractions.

so, we’ve been trying to just input thosesimple mathematical structure with a few degrees of freedom, these quarks and gluons, and then see how these, for example, atomicnuclei emerge from these simulations. >>neil degrasse tyson: so, you’re buildingthe universe from the ground up? >>zohreh davoudi: exactly. but what are thelimitations? we don’t have infinite computational resources. we have very large super computers in the nationallabs, for example, that we can compute these interactions basically and build up these systems.

however, we are still limited. and the reasonis that if you’re interested in simulating the universe, and you don’t know what thesize is— it could be finite or infinite. however, weare limited to a finite size. on the other hand, if you think about evena finite side, there are infinite numbers of points on these in this finite size that you have to simulateto get the physics right. however, we are not capable of inputting infinite number ofinformation in our computers. also, we want the simulations to be quantum,which means that there is not just one single path of evolution from one point to the other.there are infinite number of paths.

some are more important than others. and,therefore, there’s another type of infinities that we have to implement in our simulationsto get the answer right. >>neil degrasse tyson: yeah, but just becauseyou can’t—we can’t do it because we’re limited, why should that mean the whole universe islimited? >>zohreh davoudi: so, wait. so, this is thepoint. >>neil degrasse tyson: i’ll wait. i gottime. >>zohreh davoudi: all right. so, we can doit, and then you—based on assumption that ifthere is an underlying simulation for the

universe that has this problem, that has the problemof finite computational resources—just as we do—then what happens? then the laws of nature, the quantum mechanicsand whatever interactions have been going on, has to be put on a finite set of space-time points ina finite volume, and then just a finite number of quantum mechanical paths to a process canbe evaluated. so, these are the assumptions. so, if thesimulator of the universe, in whatever form it is, is just finite computational resourceand not infinite,

then it’s limited to simulate the universein this kind of limited scenario, just as we do. and then by making that assumption,and then going back and look at our simulation and see what kind of signatures we see inthe observables we calculate, that could tell us that we started from anon-continuum space-time. then apply it to an underlying simulationof the universe and make the same assumption, then what would you see? and that’s basicallywhat we look for, and list a few observables in our universethat might lead to actually constrain this scenario under this assumption. and one of which is looking at the spectrumof cosmic rays. because what happens if these

very high energy cosmic rays that approachthe earth, they are actually traveling in a discretespace-time, as opposed to a continuum. then their equations that basically special relativity that woulddescribe the relation between the energy and momentum of this particle is modified. and then you would ask what would that modificationmean in terms of the observation we make in ourobservatories, for example, spectrum and distribution of these cosmic rays. and if we see something that would be hint,that would be consistent with the scenario

of a limited computational resources of theuniverse. and then you might think about other signatures and maybe taking this scenariomore seriously and think about [unintelligible 22:23]— >>neil degrasse tyson: so, cosmic rays, itwould be your pathway to the limits of what has ever been measured. >>zohreh davoudi: exactly. >>neil degrasse tyson: and then seeing atthat limit you’re probing the limits of the programmer of the universe. >>zohreh davoudi: right. because these cosmicrays are the most energetic particles that

we’ve ever been able to observe. we can’t even produce them in laboratories.these are very high energy cosmic rays. >>neil degrasse tyson: they’re higher thananything we produced in our particle accelerators. >>neil degrasse tyson: yeah. >>zohreh davoudi: yes. by orders of magnitude.and, therefore, because these are very energetic, they can actually probe the fabric of space-time. this is our wayof probing if the universe—if the underlying space-time is discretized or just a continuum. >>neil degrasse tyson: so, max, like i said,you’ve written a book on this. yet, you

told me offline that you have an argumentthat would argue that— >>max tegmark: that maybe we’re not simulatedafter all? >>neil degrasse tyson: yeah. maybe we’renot a simulation after all. so, where does that land? >>max tegmark: yeah. so, before giving a counterargument, let me give the pro argument. of course— >>neil degrasse tyson: so, you can give argumentsin both directions here? >>max tegmark: it’s fun to argue with yourself. >>max tegmark: of course, we all—as davidmentioned—have seen the argument,

the idea, of us being simulated in the matrixand in science fiction going even far beyond that. but the guy who really started foreseeing scientists to take this a bit moreseriously, and gave this idea a bit more scientific street cred, i think, is nick bostrom, my fellow swede—nick bostrum—whopublished this very dry academic article that’s pointing out that— >>neil degrasse tyson: he’s a philosopher? >>max tegmark: indeed, indeed. and he pointed out that it seems like thelaws of physics allow us to build amazingly

powerful computers way beyond what we have now; solar system-sizedthings, which could simulate minds that would feel just like us. and then he went on tosay it seems overwhelmingly likely, if you don’twipe out here on earth, that in the future the vast majority of all computations andall minds will be inside of such a computer. and, therefore,he said if almost all minds are simulated, we’re probably simulated. so, that’s thepro argument. now, it sounds good, but— >>neil degrasse tyson: so, just to clarify,so what you’re saying is

if simulating universes becomes a pastimeamong those who have access to high powerful— to highly powerful computers, and we are ina universe, we’re probably in a simulated universe, even if one of those universes isactually real. >>max tegmark: right. that’s basically— >>neil degrasse tyson: is that a fair— >>max tegmark: that’s a fair summary, yeah.and if you’re not sure at the end of the night whether you’re actually simulatedor not, my advice to you is go out there and live really interesting livesand do unexpected things so the simulators don’t get bored and shut you down.

>>neil degrasse tyson: is that the cause ofdeath? okay. >>max tegmark: but now in terms of the counterargument,if you just take nick seriously— >>neil degrasse tyson: that’s the causeof death. >>max tegmark: there’s something fishy here.because suppose you buy into this and you’re like, okay, i’m sold on nick’s argument. we are simulated. let’s talk then about our simulated universe.we’re measuring the laws of physics here in the simulated world. and we find that inthe simulated world we can build all these supercomputers in the future,

and there’ll be all these simulated mindsand so on. and we can make the same argument all over again and convince ourselves thatactually we’re doubly simulated. and then we’rea simulation in the simulation, and then you can repeat the argument again and say, well,okay, we’re in a simulation in a simulation. but in the future, there’re going to beall these simulated, simulated computers and they’re going to have all these minds. so,we’re actually triply simulated. no, we’re quadruple simulated, and it goes on and on all night. >>neil degrasse tyson: so, the turtles allthe way down.

>>max tegmark: turtles all the way down. andat this point, i get this sinking feeling that there’s something rotten at the core of this argument. >>david chalmers: the answer is we’re atlevel 42. >>neil degrasse tyson: good answer. >>james gates: no, no, 137. >>neil degrasse tyson: one-thirty-seven. that’sthe fine structure constant. >>james gates: of course. >>max tegmark: and i think where the problemlies

is that when you make this argument aboutwhat kind of minds are really the most common, the most simulated and non-simulated, it assumes to answer that you have to knowwhat the actual laws of physics are. but if you start making these other arguments,we have no clue as to what the laws of physics are. it doesn’t matter what the laws herein our simulation— if it is one—are. we need to know what thereal laws of physics are in the basement universe that’s the foundation. and, if so, we don’treally have access to that. so, that’s the philosophical nitpick, whichseems to be swept under the rug here. >>neil degrasse tyson: jim, where—

>>james gates: where am i? >>james gates: well, first of all, i havea finger. and i look at it, and it seems to be real. and so my point of view is very conservative.it was carl sagan who once said that, “extraordinary statements,” and i’m paraphrasing— >>neil degrasse tyson: claims, yeah. >>james gates: right. “extraordinary claimsrequire extraordinary evidence.” now, zohreh has told us about a kind of evidence.and that’s the kind of evidence that would convince me as a physicist. but what i do

is sort of a mathematical model of physics.and in our previous encounter here on this stage, i had a chance to tell you about theseerror-correcting codes, which are very specific kind of digital data.it’s not just general digital data. it’s a very specific kind that seem extraordinarilyunlikely. and i have to tell you that one of the reasonsi enjoy talking to audiences like this is they get us experts out of our comfort zone.and so one of the first non-physicists that i talked to, or that i read reflected on my comment, saideffectively— this is not exact words, but effectively hesaid if the simulation hypothesis is valid,

then we open the door to eternal life and resurrection and thingsthat formerly have been discussed in the realm of religion. and the reason is really quitesimply. because if you think about a computer— if we are a simulation, then we’re likeprograms in a computer, as long as i’m a computer that’s not damaged, i can alwaysrerun the program. so, if you really believe that we are in a simulation, and there’ssome structure that runs that simulation, unless something damages that structure, thenwe can be repurposed. and so it starts to break down a very funny barrier between what people often think as the conflictbetween science and the conflict between faith.

>>neil degrasse tyson: so, what you’re sayingis that if we are simulated, that means there’s a code that’s doing it, and that code was started at some point. andin principle, it could just be rebooted, and then all of this would happen exactly theway it happened before because it’s running the same computer program.in principle. >>james gates: if one accepts the simulationhypothesis as an accurate description of nature— >>zohreh davoudi: i would say that’s a uselessexercise. what would be more interesting is to actually— >>neil degrasse tyson: the word was useless,jim, in case you missed that.

okay, you heard that. okay. emphasis on useless exercise. go, zohreh.go. >>zohreh davoudi: trying to repeat what you’vealready done with huge computation resources is useless. what is more interesting is to go and change the parameters of thesimulation—the input parameters. just put the same laws of nature, and then just changea little bit the value of the parameters—the very fundamentalparameters of our universe. and then let it run and see what happens. it’s actuallyvery interesting idea— >>neil degrasse tyson: it’s a fun thingto do, as a scientist.

>>james gates: but in changing those parameters you might cancel out my existence, in whichcase i don’t think that’s very useful. >>neil degrasse tyson: the universe withoutjim. so, lisa, isn’t this some of the foundation— couldn’t we account for a multi-verse inthis very way? that multiple-verse is multiple universes as i understand them will have slightly different laws of physics.maybe they are themselves the experimenter’s search. >>lisa randall: okay. so, let’s slow downa bit here. so, first of all, i actually want to addresssome of the things that have come up already.

one of the questions is probability; bostrum’s argument or whatever, that we’re likely to be in a simulation.i mean, part of the problem is that probabilities have to have a well-defined meaning, or areonly useful when they have a well-defined meaning. so, among all possible scenarios we can actuallysay which one is more or less likely. when we run into infinities, when we run into— it stops making sense. i mean, i could sayreally by probability i’m very likely to be chinese

because there’s a lot more chinese thanamericans. but i’m clearly not chinese. so, probabilities are tricky, and you haveto be careful what you mean when you’re saying them. another thing is i actually find the egotismof thinking that if there was simulators around that they’d come up with us kind of audacious and ridiculous. i mean,i think it’s a very self-centeredness to this whole thing that kind of i find hilarious. but in terms of feedback—in terms of error-correctingcode, i think it’s very likely that there weregoing to be feedback mechanisms in whatever

universe survives because if there aren’t,i mean, there’s always going to be mistakes. and if mistakes can propagate and just cutthings off, those universes don’t survive. so, therehave to be—i mean, for any universe, simulated or non-simulated, there has to be error correction.so, that has to be part of it. >>neil degrasse tyson: right. that assumesthat the programmer makes the same kind of programming—is susceptible to programmingerrors and programming bugs that we are. >>lisa randall: it’s not even intentional.it could be just that the computer itself is subject to error. i mean, it’s only firingthings somewhat random—i mean, ultimately, there’s uncertainty in everything. nothingis created perfectly.

>>neil degrasse tyson: quantum uncertainty. >>lisa randall: so, [unintelligible 32:51]. >>james gates: can i jump in here? >>neil degrasse tyson: what? >>james gates: because she’s raised—infact, i think an incredible point about this. >>lisa randall: as long as you come back tome afterwards. >>james gates: maybe i take a few times? i’ll[unintelligible 32:59] minutes back later. >>neil degrasse tyson: yes, okay. >>james gates: this point about error correctionis something that

when people have—general public has lookedat my work, they say, “oh, you must believe in simulations.” and i’ve said, no, actuallyi don’t. and the reason is because precisely the pointthe lisa points out. if you look in all of nature and ask are thereany other places in nature—not in engineering, not in computers, not in the things that webuild, but in nature herself, is there a discussionin science about error-correcting codes? it turns out there’s one place and one placeonly that i have been able to identify. that’s in evolution and genetics. and there’s beena discussion— >>lisa randall: or any biological system.

>>james gates: right. or any biological—right. and it’s not that we think life is somekind of programmed simulation. it’s because the universe itself, as lisa had said, has to have feedback mechanismsthat basically sustain a structure that propagates faithfully forward in time. and i think that’sin fact the most critical point. and you have your time now. >>lisa randall: thank you. and anyone whowants to take my time to agree with me— [laughter and talkover] >>lisa randall: but as far as the multi-versetheory goes,

so we have to be careful by what we mean bythat. i mean, at some underlying level we still think it’s physics in action. now, what might changein different universes, we might actually have different forces. we might actually havedifferent strengths of interactions; the kind of thing that gets simulated. i mean,we simulate strong interactions the way that were described. >>neil degrasse tyson: just to be clear, stronginteractions are the forces that bind atomic nuclei. >>lisa randall: so, protons.

>>neil degrasse tyson: yeah, protons thatare the same charge that are sitting right next to one anotherin a nucleus. and how’s that even possible when we were taught that like charges repel? so, there’s got to be a really strong forcedown there holding it together. and there is a really strong force. it’s called thestrong force. okay, so go on. >>lisa randall: which is strong. >>neil degrasse tyson: yeah. okay. just to be clear. >>lisa randall: so, and there can be differentpossibilities for what these parameters can

be. it’s still underlying you still believethat there’s the laws of physics that are operating. so, the question—i mean, so it’s not asimulation. it’s just— i mean, it’s in principle possible thatthere are universes we don’t communicate with that are so far away we’ll never send asignal, they’ll never send a signal. so, for all intents and purposes, there just are different universes. that doesn’t mean they’resimulated. it just means they’re different from ours and they can have different properties.

to really distinguish a simulation, you reallydo have to see just our whole notion of the laws of physicsbreaking down, or some of the fundamental underlying properties. so, it would be extremelyinteresting to look for the kind of violations of [unintelligible 35:43] thatwere discussed earlier, or things like quantum entanglement no longer hold it. not becauseof interaction of the environment, but just the computer just couldn’t keep track ofstuff. i mean, that’s stuff that gets so— i mean, a lot of the simulation idea—i mean,to simulate the universe, you need the computational power of the universe. so, all of the simulationsare based on the idea that there are some approximations that we don’t see,

but you have to be able to hide them. so,what we’re really looking for is the breakdown of the assumption that those approximations are valid. >>neil degrasse tyson: but, david, what doyour philosophical circles say about proposing an experiment that might falsify these ideas? >>david chalmers: look, i don’t think you’regoing to get conclusive experimental proof that we’re—we’re certainly not goingto get conclusive experimental proof that you’re not in a simulation. i suppose wecould get some kind of various— >>neil degrasse tyson: well, why not? youjust declared something. why can’t a clever person come along and—

>>david chalmers: because any evidence thatwe could ever get could be simulated. that’s basically the reason. sorry. maybe— >>neil degrasse tyson: so, if i find evidencethat we’re not simulated, the great simulator— >>david chalmers: they could have just plantedthat for you. >>neil degrasse tyson: —put that in. >>david chalmers: yeah. they’re one stepahead. however— >>neil degrasse tyson: we’re done. we’redone here. >>david chalmers: maybe we—we probably couldget pretty strong evidence that we are simulated. if someone wrote upin the sky, “sorry, guys”—the stars

suddenly rearrange themselves into, “sorry,guys, it’s all a giant simulation.” and then they took over the internet and— >>neil degrasse tyson: except it would bein chinese to get the most number of people to read it. >>david chalmers: then we’d probably havea pretty good reason to think we’re in a simulation. either that or theweirdest non-simulated universe that anyone ever imagined. so, for a philosopher anyway, it’s not fundamentally a matter of experimentalproof. it’s cool. i really like zohreh’s experimental evidence that we’re in a simulation.but i think around here it’s really important

to make a distinction that there’s a hypothesis that we’re ina simulation. there’s a hypothesis that the universe is computational. those are closely related. if we’re in asimulation, the universe is fundamentally computational. but it’s not true that thisuniverse is fundamentally computational we’re necessarily in a simulation. because the simulation hypothesis is a combinationof two things. >>neil degrasse tyson: that’s an officialthing, the simulation hypothesis. >>david chalmers: yeah. the simulation hypothesissays we’re in a computer simulation. a computer

simulation’s a computation that was created by someone for a purpose.so, basically the simulation hypothesis is that computation hypothesis, plus something else about someone who createdit. and around here is where you might be able to get a little theological and say, okay, well, it’s anaturalistic version of the god hypothesis. but, anyway, my worry about zohreh’s stuff, which is really cool, it’s really evidencefor the much weaker hypothesis that the universe is some form of discrete computation and iscompletely neutral

on the question of whether this is actuallya simulation in the sense of something that was created— >>neil degrasse tyson: with intent. >>david chalmers: —by a simulator. >>neil degrasse tyson: so, max, do you mindif i call you mario from now on? because if you’re mario in the computer game— >>max tegmark: starts with m-a, so [unintelligible38:46] for the two letters, yeah. >>neil degrasse tyson: i imagine mario—someonecoming into a mario game and calculating how high he jumps and howfast he runs and coming up with the laws of

physics of the game, and possibly then questioning why is it that and not something else perhaps.and so, fine, but is there—why would that allow someone in the game to have any understandingof what’s outside the game? >>max tegmark: yeah, that’s a really deepand good question. mario might—if mario can ever—even if he figures out exactlythe rules of his world— >>neil degrasse tyson: then he just figuresout the rules. >>max tegmark: —he won’t even know ifhe’s running on a mac or a windows box or a linux box because all he has access to is this higherlevel of this sort of emergent reality. and

we might, at some level, be stuck in that situation in physics also. it’squite fascinating to think that so much of what we’ve figured out, for example, abouthow a glass of water works with waves and vortexes and things, we figuredout already without having a clue about the substrate. we didn’t even know there wereatoms. but the same kind of questions that you’re asking, which i think are awesome, the kind of questionswhere you ask suppose this is actually somehow simulated, suppose the simulators cutting corners, howwould that show up?

actually, it has been incredibly useful inthe past. if you imagine going back 200 years and trying to simulate this water as an infinitely— a continuous liquid where there’s a pressureand a density that has to be defined with infinitely [many 40:25] decimal places andinfinite points, that sounds horrible to simulate. so, maybewhoever did this cut corners. maybe there’s a smallest kind of chunk of object—let’scall it atom or something— you can figure out then what are the departuresfrom this simplified continuous physics that i’m guilty of teaching my undergrads atmit about this morning? and you would figure out a way there’s thisone little thing, which is different.

>>neil degrasse tyson: he trained down a fewhours ago from cambridge. >>max tegmark: yeah. >>neil degrasse tyson: thank you for comingand for— >>max tegmark: brownian motion that thingsshould jiggle around in a weird way. and einstein found that, got the nobel prize for it importantly. andi think that the sort of thing you’re doing is awesome. look for corner-cutting evidence. i suspectthat whether we’re simulated or not there are a lot of things that are wrong about whatwe assume today.

i am very skeptical that we really have acontinuous space that can be stretched infinitely many times. it seems like some sort of simplificationthat we came up because it was easier to do the math. >>zohreh davoudi: but do you ever ask whyshould that be the case? why do we need a discretized universe? i mean, if you put away the simulation hypothesisor a computational hypothesis, why should we even think about a discretizeduniverse? why not continuum? it’s [unintelligible 41:42]. >>neil degrasse tyson: so, this is an important—

>>neil degrasse tyson: i don’t want to callit a problem in physics, but a reality of physics that our macroscopic world looks continuousto us. and that has a certain simplicity of modeling. and then as you get smaller andsmaller and smaller, it’s no longer continuous and it’s discrete, which may be easier tocalculate than being able to be divisible all the way down to an infinitesimally smallbit. because now you need that much bigger computerto do it. by the way, we have— >>lisa randall: so, you know something thatnone of us actually know. this is actually a real question, whetherspace is discrete at really small scale.

>>neil degrasse tyson: well, we run into thisproblem when we do flyovers in the hayden planetarium. we have a data set for a planetarysurface— let’s say mars—and you had a given distance.and from that distance you can see olympus mons, the biggest mountain around, and vallesmarineris, and you say, fine, now i want to get closer. well, to get closer, and have more informationcome to you, you have to swap in a higher resolution map. and we try to do that continuously,so you don’t realize that. so, you keep doing this, and then you reacha point where we don’t have more resolution to give you. so, we actually hold you back,

so you don’t go closer. but if you did,all of a sudden you see these discretized pixels of the martian surface. and that’s basically because we don’thave the data. we’re not there. it doesn’t exist for us. >>david chalmers: so, anyone’s who’s usedone of these virtual reality devices, like the oculus rift, knows there’s somethingcalled the screen door effect. it’s like you can—if you look closelyenough you can see the pixels, so it’s not a perfect simulation. so, i guess really whatzohreh is doing is saying, well, we can get empirical evidence for a screen door effectin real physics.

>>zohreh davoudi: yeah, i think it’s actuallya deeper question than that. it’s not about not having enough data to resolve those distances,but to some extent that’s true. but the problems is something that even botheredfeynman a lot that why do you need infinite numbers of degreesof freedom, or infinite amount of information, to describe a very tiny chunk of the space-time?that just doesn’t make sense. you can pretty well describe the physics withoutactually needing that infinite amount of information. >>neil degrasse tyson: what i meant to addis that when we’re zoomed down to mars, it’s not only that we don’t have the data, even if we did have the data, you would needthat much bigger

disk space to have it ready and loaded tobe able to go from the bird’s eye view down to any kind of small— i mean, we rapidly run out of capacity tocalculate. >>max tegmark: and that’s a great controversythat even mathematicians have been really arguing passionately about for over 100 years. gauss, one of the greatest mathematiciansever, said—or kronecker actually said god had created the integers and everything else was just the work of man.all this continuous real numbers with decimal places and stuff.

i mean, frankly, as a physicist it feels kindof hubristic to say that you need an infinite amount ofinformation to figure out the height of my wine glass or anything. nature seems perfectlyabout to figure out what’s— >>neil degrasse tyson: there’s water inthat glass, by the way. >>max tegmark: yeah, what to do. and we havethis toy model that you need an infinite amount of information to do things. i think you’re on to something very deep[unintelligible 44:56] and that nature actually—infinity is just something we made up for convenience. and as we dig deeper, we’re going to findthat maybe even space and time itself is at

some level digital. >>lisa randall: so, can i just say somethingby way of clarification? which is just in we don’t actually prove any theory. we canrule out theories. so, we can rule out a lot of alternative theories,but in any case you can always have the possibility that you can dig deeper and find that whatever theory you thought was the mostfundamental has some underlying structure. and so that’s why all the physics we’vedone works. that’s why we really don’t need to have an infinite amount of informationat any time because we don’t have access to an infiniteamount of information. and we can’t even

ask the question or tell whether or not there’sthis underlying infinite amount of information. so, it’s not just we can’t just ask thequestion whether the universe is a simulation. we can’t ask if any physical theory is absolutelycorrect. we’ll never know the answer to that. all we can know is that we’ve tested itup to a certain level, at a certain level of precision, over a certain range. and so these questions all [unintelligible46:05], and that’s why i can describe this glass of water without knowing about atoms, because i didn’t have—wasn’t doing anexperiment where the effects of the atoms

became manifest. and the same might be trueof the universe as a whole. so, we can have in the back of our mind theremay or may not be an infinite number of degrees of freedom. but that’s not what we’reactually testing. >>max tegmark: let’s disagree on one thing,though. i think there’s one fantastic example wherewe can tell it makes a huge difference. i think the biggest embarrassment we have arguably in fundamental physics and cosmologyright now is this fact that inflation, if it goes on forever, makes this multi-verse,and then we can’t calculate probabilities, like you so eloquently said in the beginning.

that comes exactly from the infinity assumption;the idea that you can take a piece of space and just keep stretching it into twice thesize forever. so, i think you should question >>lisa randall: well, it doesn’t have tobe infinite. it could just be a large number. it could be 10 to the 500. i mean, it doesn’treally matter if we say it’s infinite. why don’t we just say it’s a lot? >>max tegmark: but you can calculate probabilitiesas long as it never gets infinite. it’s exactly infinity that [unintelligible]— >>neil degrasse tyson: so, he’s cool with10 to the 500, is what he’s saying, which seems like a really big number.

>>lisa randall: i know. >>neil degrasse tyson: that like equals infinityto me, i think. >>lisa randall: but that’s exactly the point.that’s exactly the point. >>neil degrasse tyson: jim, is there any functionaldifference at all between admitting that we live in a computersimulation and saying that’s basically a secular god? what’s the difference? >>james gates: well, first of all, i’vedecided my name should be morpheus, not jim. >>neil degrasse tyson: okay. well, let me—

>>max tegmark: i’m mario. nice to meet you,morpheus. >>neil degrasse tyson: morpheus. >>james gates: exactly. >>neil degrasse tyson: yes. you have to seethe movie the matrix and play video games to follow this conversation at this moment.morpheus. >>james gates: but as i said, for non-scientists— because i’m going to make this partition.i think for non-scientists, an acceptance of the simulation hypothesis as an accurateview of our universe is equivalent, i believe, to the notion ofa deity. i don’t understand how, for a non-scientist,

you can make that distinction. for a scientist,however, we are [rather] secular. the definition of science is actually a seculardefinition. and, in fact, it’s the definition that comes to us from galileo. einstein quotes galileo as being the father of all science because galileo—and theseare einstein’s words—drums into us that contemplation alone, without observation ofnature, is totally useless in trying to come up withan accurate view of nature. so, it’s that ability of us—our human ability to observethe universe that actually defines science. so, if youcan’t give me something that i can observe,

i don’t know how to do science. >>neil degrasse tyson: okay. so, what you’resaying is that if in fact there is a programmer whowould be philosophically equivalent to a creator, and you can’t observe them, they’re just outside the realm of science. >>james gates: i think that’s the definition. >>neil degrasse tyson: david, do you haveto be defined by that? >>david chalmers: well, i think there’sa theological reading, if you like, to the simulation hypothesis. it says all this wascreated,

but what’s interesting is at the same timeit can be seen as a kind of a naturalistic theology. a naturalistic hypothesis—fromthe point of view— >>neil degrasse tyson: is that the first timethe phrase has ever been uttered? a naturalistic theology. >>david chalmers: i think it’s out therealready. >>neil degrasse tyson: oh, it’s out there.okay. all right. >>david chalmers: simulation theology [unintelligible49:36]. simulation theology is the coolest kind ofnaturalistic theology, from the point of view of the—

>>neil degrasse tyson: actually, there’sa book in 1750—or who was it? >>david chalmers: yeah, david hume was intonaturalism. >>neil degrasse tyson: no, there was—whowas the fellow who wrote the book natural theology? there was a book with that very title. >>neil degrasse tyson: but not natural simulationor simulated theology. >>david chalmers: if you think about is fromthe point of view of the simulated— i mean, we in this universe can create simulatedworlds, and there’s nothing remotely spooky about that. people are already doing it withvirtual reality and the sims and second life.

and whatever this is is just a far more sophisticatedversion of that. so, we just need to move that picture to thenext universe up and say, hey, maybe that’s what’s happening tous. so, we got a creator, but our creator isn’t especially spooky. it’s just some teenage hacker in the nextuniverse up whose mom’s calling him in to dinner. >>neil degrasse tyson: working in the basement,yeah. >>david chalmers: so, i think you could beled to at least entertain this idea by perfectly naturalistic ideas as, say, nickbostrum was and say, okay,

maybe this is the kind of theology which evensomeone who’s got no sympathy for spooks and gods and ghosts, needs to object to. >>neil degrasse tyson: so, that’s an interestingpoint because we don’t think of ourselves as deitieswhen we program mario, even though we have all power over how high mario jumps. because that’s a line in the code. so, you’reright. you just take it up a few notches. there’s no reason to presumethey’re all powerful other than just they fully control everything we do, say and think. >>david chalmers: could be they’re all powerful.i got into this from watching my five-year-old

nephew playing with one version of the sims or simlife or something. he’d make a whole town. he’d build up the buildings, and you got the trees and the jungles andthe creatures. and then he’d say now comes the good part, and he’s send down fires and floods andsuch. i was like, finally, i understand the god of the old testament. >>neil degrasse tyson: because it is truein our world we have fires and floods. i played one of those sims—sim city becausei’m a city kid. and—the early, early low-res

simulation. and there’s a feature, you build up the—you need money. you’remayor of a city, and you construct buildings and you need the schools and the fire departments. and then every now and then godzilla stompsthrough your city and you say that’s not real. i’m tryingto be real. but then it’s kind of real in the sense that some major disaster can— you will confront like hurricane sandy or9/11. now, you’ve got to redistribute resources. so, i look at our real world, and these thingsactually do happen. so, are they just trying to mess with us? is that—

>>david chalmers: the way i think about—imean, who knows if there’s actually a simulator who’s actually doing any of this. but ifyou do take the simulation hypothesis seriously, it’s got a couple of elements of a traditionalgod. this person could be all knowing about our universe, could be all powerful. the onething which is probably missing is wisdom and benevolence. if there’s a simulator,i refuse to worship you. you may be out there, but you have established yourself as beingworthy of worship. i refuse to [unintelligible 52:53]— >>neil degrasse tyson: right. because they’reall powerful and all knowing, but not all good.

>>david chalmers: there’s no reason to thinkthey’re all good. >>max tegmark: cut him some slack. he’sonly five years old. >>david chalmers: you’re going to be maturingone of these days. >>neil degrasse tyson: zohreh? >>zohreh davoudi: yeah. so, i think thereis a big danger in trying to compare our idea of simulation with what comes withcomputer games, whether you’re talking—at least in my point of view and i think a physicist’spoint of view. what’s called the simulation is you justinput the laws of physics, and nature and universe emerges. you don’tactually try to make it look like it’s something

going on. you don’t try to— the same as with computer games. you don’tinterfere with what you’ve created. you just input something that is very fundamental and just let it go, just as our universe. >>max tegmark: like [deitism]? >>zohreh davoudi: yeah. >>neil degrasse tyson: in other words, youset the laws into motion and let the universe unfold. >>neil degrasse tyson: however those lawsprescribe.

>>zohreh davoudi: because a priority—youdon’t know what happens because the universe is complex. the laws of physics are simple, but you don’t know what kind of complexitiesyou should expect. and then you just get it wrong and things emerge, and we just watch. >>neil degrasse tyson: but, lisa, in the searchfor the theory of everything, isn’t that got a little bit of this in it?once you find the theory of everything—and you’ve been on two of our theory of everythingpanels here— you’re going to find out the one equationthat the five-year-old working in the garage

wrote down that made our entire universe. >>lisa randall: well, you might recall, sincei’ve done this a couple times, that the theory of everything, i think, is very badly named for a lot ofthese reasons. because even with the equations, as was pointed out earlier, you could start your system in very differentways. you can have different conditions. and there’s a lot that we don’t understand. i mean, even if i understood quantum gravityat a fundamental level and could derive all the equations,

that’s still not going to help me predictwaves at a practical level. i mean, the computer simulation will never be that detailed, in my opinion. it’s much better to go todifferent levels and figure out what’s going on at what i would call an effective theoryapproach. so, even with the fundamental equations— now, i mean, clearly if you had infinite computingpower, then you would just be literally mimicking the universe. and possibly you could do that.but short of that, you’re going to have to find these approximations,these descriptions that are sort of somewhat in between. they’re still science. they’re not something i’m just making.there’s still equations that work, and they

ultimately are attributable to whatever is that fundamental equation.but that doesn’t mean it’s fundamentally how we’re computing it. it doesn’t meanit’s fundamentally how it’s working. >>neil degrasse tyson: but, zohreh, you startedthis whole discussion by describing—trying to obtain an understandingof the basic forces of nature and the particles and build up from there. but isn’t there surely a gap between whatyou know drives the behavior of individual particles and what might be emergent features in a macroscopicsystem. isn’t that true with the gas laws?

we learn gas laws in the first week of chemistry, but i don’t know that you can get the macroscopicgas laws by knowing every single particle at every single instant. i don’t know that they’re fully reducibleto that. so, can you admit the possibility that there are gaps and that there’s emergent phenomena that—so,starting at the very basic level won’t get you there? is that possible? >>zohreh davoudi: i do admit to that, andit is in fact—

>>neil degrasse tyson: okay, good. thank you.you admit to it. no, go ahead. >>zohreh davoudi: no, this is indeed a fieldof research now, for example, in nuclear physics we know that these microscopic features aboutparticles and building blocks of that would contributein strong interactions, but we don’t know exactly how to get thesecomplex system of nuclei. and we have very good microscopy and [unintelligible56:51] models that describe all these larger-scale phenomena, but we still don’t know how to get themfrom this phenomena.

so, that’s what, as physicists have to— >>lisa randall: in principle, if you coulddo it—i mean, if you had infinite computing power. >>lisa randall: in principle, you could actuallysee a system that exhibited the gas laws. the question is whether we as scientists wouldcall them—deriving the gas laws. it wouldn’t be a very useful description. it would mean that we’d have to have theseenormous computations every time to do it, rather than solve an equation that, as youknow [unintelligible]— >>neil degrasse tyson: oh, so i never heardthat before.

you’re assuming that if in fact we couldcompute the behavior of every single particle in a gas, that out of that would emerge the macroscopicgas laws. >>lisa randall: but it would behave accordingto the gas laws. that doesn’t mean that you [unintelligible]— >>neil degrasse tyson: okay. that’s confident.so, what you’re saying is it’s not emergent because i’m intrigued which of you mentionedthe water— >>lisa randall: no, emergent means that itemerges from the fundamental laws. >>neil degrasse tyson: but because we understood,to a very high degree, a fluid dynamics

long before we knew that fluids were madeof atoms. >>lisa randall: right. >>neil degrasse tyson: and i don’t knowhow much the public knows that atoms are—though, the idea is old, evidence that atoms are real is relativelyrecent. and even as recently as the year 1900, itwas still kind of not sure. and it wasn’t really until einstein andbrownian motion in 1905 where there’s really good evidence that atoms were real things. yet, we had full understanding of fluid dynamics

in any way that mattered for us. >>lisa randall: right. but we also now canderive fluid dynamics from the atomic description, in certain cases. not all fluid dynamics, but some of the propertiesof condensed matter physics we can derive by that. >>neil degrasse tyson: okay, i’m glad tohear that. so, we’re still talking about reducible things. >>max tegmark: they’re two separate things,though. we mustn’t conflate. on one hand, i think in principle it can deriveall these higher level things,

i think, even ultimately even consciousnesslike david chalmers is working on, from starting out with a quark as the [unintelligible 58:53]— >>neil degrasse tyson: you’re going to bringconsciousness into this? >>max tegmark: and practice, on the otherhand, whether we humans are smart enough to figure it out. that’s a whole different story. and i thinkthat’s— i’m guessing that’s what you were gettingat there. you weren’t saying that there’s some mysterious [unintelligible 59:04] gapthat we can’t— >>zohreh davoudi: oh, no, no. that’s notwhat i meant.

>>max tegmark: but that we might be able tounderstand. >>zohreh davoudi: we haven’t yet have theresources and probably enough tools and understanding to fill that gap. but the phenomenal equations are there. it’sjust a matter of when we actually get there. >>neil degrasse tyson: so, i’m curious—thisbrings me to a point that we did not discuss earlier in the notes that we shared. you can know everything you can about cellbiology, about how life works. and it’s not obvious to me that by juststudying a single life form that you can derive evolution by natural selection.that that’s an emergent phenomenon given

the system. so, if it’s emergent, then no one actuallyprogrammed it in to do that. that’s just something that resulted. >>lisa randall: right. so, the way i woulddescribe it is i would say that the fundamental— whatever’s fundamentally there—that substrate—isessential to whatever happened, but is not necessarily essential to your descriptionof what happened. and so the laws are following from this, butit’s not giving an explanation. so, i can note that there’s atoms, but itdoesn’t help me predict what will happen when i throw a ball. i mean,in principle i could probably figure it out

based on that; put it all together, but it won’t help me.it’s so inefficient. so, it’s much better to have a descriptionof a solid ball, even though it’s made of atoms, which are actually mostly empty space. so,that solid ball description leaves all that out, and it works just fine.it tells me exactly where the ball will land [unintelligible 60:43] measure it. >>neil degrasse tyson: david, you and yourconsciousness cronies, is it generally recognized that consciousnessis an emergent phenomenon of a complex brain?

>>david chalmers: yeah. well, this word emergenceis kind of word that people used to cover a huge variety of sins. i mean, sometimes i think it’s kind of amagic word we use to make ourselves feel comfortable with things we don’t really understand.so, ah, that’s emergent. there’s different kinds of emergence. there’sthe kind you get with, say, complex systems like the game of life; conway’s game of life where the cells blipon and off, and you get complex phenomena like glidersthat move along. you know it’s surprising, and you wouldn’thave expected it, but you can put together

the equation that it’s totally predictable. you run the game of life over and again withsimple computational rules, it’ll be predictable again and again. evolution is interesting at the immediatecase. maybe given the laws of physics in certain initial conditions. you can run them again and again. i don’tknow. maybe you’ll get—maybe it’ll turn outevolution arises 60 percent of the time. if so, that’s incredibly cool, and thenthat ought to be explainable in principle. now, for consciousness, people sometimes sayconsciousness is emergent,

but there’s a gap there of a kind that wehaven’t even begun to close in the gap of consciousness. people can tell stories about life. peoplecan tell stories about evolution. no one’s even begun to tell a story thatenables you to predict the existence of consciousness from any number— any amount of underlying physical dynamics. it explains the behavior. it explains howwe walk, how we talk, but why that should actually feel like something from the first-personpoint of view, that is emergent in a much stronger sense.i’d say that’s strongly emergent in the

sense of it might require new principles toexplain. >>neil degrasse tyson: max, is there any roleof chaos theory in this? because we know that in principle and in practicethere’s some systems that are so complex, that you cannot accurately predict its futurebehavior. now, is that true even if you had an infinitelypowerful computer? >>max tegmark: no matter how powerful a computerwe build on earth, we can certainly not predict—we could nothave predicted that the red sox were going to win the world series right after i movedto boston. >>max tegmark: because precisely of chaostheory, where tiny

changes in the position of some particle madea huge difference later on. but— >>neil degrasse tyson: just the butterflyeffect. >>max tegmark: yeah. if things— >>neil degrasse tyson: i’ve got to tellyou real quick, there’s the journal of irreproducible results, which is if you’re a scientist and you comeup with something that you know isn’t right, but it’s a really cool calculation, youpublish it there. and it’s like in there you’ll find the calculation of what happens

if you strap a jellied toast to the back ofa cat. since toast always lands jelly side down,and cats always land on their feet, what would happen if this dropped? okay. and so in the paper, they hypothesize thatthe cat falls, and then hovers over the— so, it’s stupid fun calculations. one ofthem was— sorry for this interlude, but one of themwas there was some major storm system that happened that hit the east coast of the united states, and someonesaid, “we found the butterfly that caused this.”

and they killed it and it was on display.so, go on. so, this butterfly effect— >>max tegmark: yeah, yeah. i was just [unintelligible64:13] complicated emergent phenomenon related to chaos and such. i just wanted to come back to what david wassaying about consciousness here, and kind of connect it with what you openedwith here. how can we test with scientific methods these ideas of whether we’re simulated ornot? or at least update our odds in one way or the other. i think one thing that’s greatto do is what you’re doing. again, looking for this evidenceof a simulator cutting corners to make the

simulation easier to run. i think another thing we should do is if youwant to test this computation— hypothesis that everything is a computation,or that everything’s mathematical, we should look precisely at the things wherewe’re the most clueless right now about how we would actually describe it mathematically.and i can’t think of anything we’re more clueless about right now than consciousness. and try our very best to see if we can bringalso that in under the type of things that we can describe with math.

if we fail spectacularly on that, and canrealize why, we’ll see, wow, our universe is not mathematical. boom, done. death to the simulation hypothesis.whereas, if you and your cronies, as we’re told that they’re called, succeed,that would i think be a big boost for the simulation hypothesis. >>david chalmers: yeah. and there are peoplewho are pursuing the idea. as you know, the consciousness is fundamentallyabout information processing in the right way when information, for example, is integratedin just the right way. maybe you get a kind

of consciousness. that’s still a very controversial idea,and a lot that it doesn’t explain. but if something like that is right, it goes very naturally, at least, with thesimulation hypothesis because it’s very natural to suppose thatin a simulation there could be all that information being integrated and giving you consciousness. certain other views—just say, for example,consciousness requires a certain very specific intrinsic property like a certain specific biology. then therecould be a simulation of the whole universe.

but if it didn’t have that biology, then no consciousness. it would just be aworld of unfeeling— >>neil degrasse tyson: [of worlds 66:11]. >>david chalmers: —zombies. >>lisa randall: i have a question, though. >>david chalmers: unfeeling physical dynamic.so, it really makes a difference. >>lisa randall: how do you ever show thatsomething can’t be described mathematically? you’d have to believe you understood fundamentallywhat the degrees of freedom are.

so, you might just have the wrong description.i mean, even in physics, i mean, we know classic exampleswhere people thought certain things were impossible until just a new law of physics was discovered. i mean, darwin got the age of the world— our world closer than the greatest physicistsof the time because darwin just looked around, and kelvin thought he knew the laws of physics,and he didn’t get them right. so, i don’t see how you’re ever goingto be able to show that something has no mathematical description. >>neil degrasse tyson: but, max, you’rebig on the mathematical concept here. what

you’re saying is everything is mathematics. and if everythingis mathematics, then everything is programmable. >>max tegmark: that’s right. that’s right.and so i think as an answer to lisa’s question, david put it very well in the beginning. inphysics, we aren’t ever able to really prove that something is true. the only people who prove stuff are mathematicians. but if david and [unintelligible 67:22] andothers succeed in this endeavor to try to actually explain consciousness mathematically, it wouldn’t prove that things are purelymathematical, but it would certainly be yet

the great boost. >>lisa randall: i asked the other questionof how you [unintelligible]. >>max tegmark: because if you just go back—let’sgo back to galileo again. we were eulogizing him earlier, right, forhis great insights. when he wrote that our universe is a grand book written in the languageof mathematics, that was 400 years ago because he was so impressedthat things moved in parabolas and things like that. he had no clue why oranges were orange andhazelnuts were hard and some things were soft. that seemed like it was beyond what he coulddo with math. then we got maxwell’s equations,

the schrodinger’s equation, the standardmodel of particle physics. more and more has been explained by math.i think galileo would be really impressed if he were on stage. so, it’s really cool to look at what arethe things left. >>neil degrasse tyson: i’ll invite him nexttime. >>max tegmark: [unintelligible 68:16]. well,you can reincarnate him and bring him on. >>james gates: just simulate him. >>neil degrasse tyson: we’ll just have tosimulate him. that’s what we’ll do. >>max tegmark: so, it’s really cool to look,well, what’s left. like consciousness, for

example, and see if we can also make some progressthere. there’s no better way to fail on anything, including consciousness understanding than to tell ourselves, oh, we know it’simpossible because of some principles, and let’s not try. >>neil degrasse tyson: yeah, those aren’tgood scientists who behave that way. >>david chalmers: i think we have to distinguish,though, between the two claims that you can give a mathematical description of everything, and you can give a complete mathematical descriptionof everything. even consciousness,

obviously, give many mathematical descriptionsof color space has certain geometrical properties, the light, the feeling of the light is more or less intense.you can give a very rich mathematical description of it. and that’s what, say, someone like [unintelligible69:04] is doing. but can you give an exhaustive mathematical description of it once you’ve given a full mathematical specificationof consciousness? [unintelligible] everything about it, or is there some further naturelike the redness of the red, or the blueness of the blue?

>>neil degrasse tyson: what max is sayingis that previous frontiers in that question were ultimately breached when enough smartpeople came along to figure it out. so, whatever’s our stateof mind today, it would be unwise to suggest that it somehow transcends any access thatthe future of math might— >>lisa randall: i mean, on some level we don’thave an exhaustive description of anything because we understand that there can alwaysbe something more fundamental, something we haven’t seen yet. >>james gates: i agree. >>neil degrasse tyson: in fact, the very wordatom in greek means indivisible.

>>david chalmers: yes. >>neil degrasse tyson: so, yeah, with that—howlong did that last? >>lisa randall: and unchanging. >>james gates: while we have been all bowingat the altar of mathematics, a number of us are aware of this result bygã¶del called the incompleteness theorem. and it even says in some sense mathematicsis incomplete. there are things in mathematics that you cannot prove. that’s what the theorems say. and so we,as humans, i think— >>neil degrasse tyson: in fact, gã¶del provedit.

>>james gates: yes. yeah, right. he provedit. that’s exactly right. >>neil degrasse tyson: gã¶del proved thatmath cannot be proven. >>james gates: that’s right. >>david chalmers: if it’s consistent. >>james gates: right. if it’s consistent. [talkover] >>max tegmark: in defense of our universehere— >>neil degrasse tyson: somebody’s got todefend our universe, so go ahead. >>max tegmark: standing up for our universe.there’s actually no evidence that our universe

is inconsistent, or that mathematics is inconsistent. gã¶delsaid that we humans, we cannot prove ever that mathematics is consistent. >>neil degrasse tyson: right. >>max tegmark: we cannot prove that—that’simpossible to prove that one equals two. but i think that’s probably more of a reflectionof our own limit—of the limitations that thinking beings have, rather than our universe has some kind ofidentity crisis. our universe seems to know exactly what it’s doing.

it doesn’t seem very inconsistent exceptwhen i watch the presidential debates. >>james gates: oh, boy, i’m not going there.but, max, that was precisely my point, that maybe what we’re talking about is infact part of our limitations. not limitations on the universe, but—in science it’s very funny becausethe way we do science— well, when i give public talks, i like tosay if you look at family in their house, you might be an anthropologist and recordwhat they do, and they turn the appliances off and on. andyou might come up with some big record book of this.

but then when everybody’s out of the house,you might just go to the house and watch how it behaves. the thermostats go up and down, and maybeyou have a timer that does other things. and so the house has a set of rules for operatingwhen you’re not there. and in some sense, in science, that’s what we’re doing. and when we do this split between science,non-science, in some sense we’re talking about how the universe behaves as if we couldtake our consciousness outside of the universe. and that’s a very sudden point to appreciate.and so maybe what this whole discussion has been about

is actually just our limitations. >>neil degrasse tyson: so, we’re all stupid,is what you’re saying. >>james gates: actually, the universe madeus very clever, at least most of us. >>neil degrasse tyson: so, jim, i got to askyou something. your discoveries of the checks—error-correctingcode within the laws of physics themselves, at the depths that you’re researching them, what i wonder is we live in the age of it,of information technology. so, we all have a certain fluency. so, it’s in our brains to think that wayat some level.

could it be that how the saying goes, if you’rea hammer then all your problems look like nails, and you solve them by hitting them. if now we are in an it revolution, and you’refinding it solutions to your problems, maybe it’s just the fad of the moment. and you’re forcing a solution that is eithernot real, or there’s a better one awaiting in a revolution that has yet to occur. >>james gates: sure. so, the last time i washere i actually misspoke. i used the name of shannon when i meant hammingcode instead.

so, first, let me correct that for this wonderfulaudience and mention it— >>max tegmark: error correction in action. >>neil degrasse tyson: error correction— >>james gates: error correction in action,absolutely. but in—look, in our work, first of all,we don’t know it’s the physics of our universe. there is a large experiment underway thatlisa knows a lot about in geneva because she has written papers about possible outcomesin these observations. >>neil degrasse tyson: lisa, are you flyingto geneva tomorrow?

>>lisa randall: i am, but not for that. >>neil degrasse tyson: not for that, okay. >>james gates: so, the large hadron collideris going to explore more of the structure of the universe. so, first, the mathematics that i have donewill only become physics, or relevant to nature, when the lhc or some other observational devicesays the idea of supersymmetry is correct. then it will kick in. so, that’s a big if. there are lots of physicistswho don’t believe the universe will be supersymmetric. in which case, all i’ve done is an interestingmathematical fairytale.

>>neil degrasse tyson: so, supersymmetricproposes a whole other regime of particles that are counterparts to the particles thatwe’ve come to know and love? >>james gates: correct. >>neil degrasse tyson: okay. and they’reyet to be discovered, but they could be describing a whole other parallel reality, awaiting our discovery? >>james gates: well— >>lisa randall: but even that—i mean, ijust want to clarify. we may or may not find evidence at the largehadron collider, which is what’s being discussed.

but that doesn’t even mean that supersymmetrydoesn’t exist. it means that we can’t find the evidence at the scales that we canprobe. >>lisa randall: so, it could be that thereis some fundamental symmetry, and it’s broken at such a high scale thatwe cannot access any of the evidence of it. and that’s the world we live in. i mean,that’s what we do as scientists. we try to simulate what we can. we try to derive what we can. we try to measurewhat we can. and then we have to allow for the possibility that we just haven’t hadthe accuracy. we haven’t had the cleverness, or we haven’thad the resources—

>>james gates: technology. >>lisa randall: —to be able to test certainideas. and so i think that’s right, that it’sa combination of what’s out there and what we can actually do. >>neil degrasse tyson: so, i don’t who amongyou to ask this direction, so i’ll just put it out there in front of you like a pieceof raw meat, and you can chase after it, if you— >>lisa randall: you think we’re dogs? [unintelligible75:30]. >>neil degrasse tyson: or you vegetarian—someraw carrots. okay. so, you can chase after

it. i don’t know if any of you are vegetarian. so— >>lisa randall: can you cook the meat at least? >>neil degrasse tyson: i’ll cook the—okay.we’ll cook the meat. my question is i remember physics 101 and102 and 201 and 202, and as you learn the laws of physics, everynow and then something pops up that’s just kind of weird. all right? you learn maxwell’s equations,which describes the behavior of electromagnetic radiation, the behavior of light,

and they’re really beautiful except there’san asymmetry in there. there’s like you can have particles thathave electric fields like electrons, but you don’t have isolated particles thatare their own magnetic fields. there’s always a plus and a minus stuck together. so, they’re not symmetric that way in theequations. and it’s like you cringe when you see that because part of us wants somebeauty and symmetry to the universe if it is—i don’t know. we’re holdingit in very high—holding very high expectations for what we want to find.

and then you go back to the early universe,and you find out that one out of 100 million— one out of 100 million photons did not becomea photon because symmetry was broken, and it made only one matter particle. whereas,all the other interactions had matter and antimatter they annihilated and became photons. and we are made of this one in 100 millionstuff that’s left over. something broke in the early universe. and i ask you why aren’t these bugs in theprogram that we’re dealing with? >>lisa randall: so, i’m going to actuallyanswer that. >>neil degrasse tyson: you’ve got an answerfor that? very cool. very cool.

>>lisa randall: so, it’s definitely nota bug in the program because in both these cases, the underlying laws actually do exhibit symmetry.as jim knows really well, that it has to do— in our description of electromagnetism, youhave electrically charged particles. there’s an alternative description wherethe fundamental particles would be magnetic. that’s not the universe we find ourselvesin. so, a lot of the symmetry is broken by the actual state of the universe we live in. so, it could be that the laws of nature havesome underlying symmetry that gets broken at some point.

>>neil degrasse tyson: so, who’s breakingit? >>lisa randall: who’s breaking—the universe.the universe is [unintelligible 78:06]— >>neil degrasse tyson: no, that’s not theanswer. i’m looking for a little more insight intowho’s breaking the laws of the universe than just the universe. >>lisa randall: well, here’s a simple example,okay. >>neil degrasse tyson: well, just to be clear,we come up with what we saw are laws, and then if we see an exception we say thatthere’s a case where the law is broken. >>james gates: no, no.

>>lisa randall: okay. let me give you a simpleexample. >>neil degrasse tyson: and we’re okay withthat. >>james gates: it’s the symmetries thatare broken. >>lisa randall: suppose i have a pencil— >>neil degrasse tyson: oh, sorry. symmetriesthat are broken. >>lisa randall: so, say i have a pencil standingon end. i have rotational symmetry, right? we’d like to believe everything’s rotationallysymmetric. why should one direction be different? so, i have a pencil standing on end. it’sgoing to fall down. it’s going to fall down in some direction.

now, who made it fall down in that direction?no one made it fall down in that direction, but it was going to fall down in some direction.so, the symmetry is broken. we didn’t ask the symmetry to be broken.the fundamental laws were perfectly symmetric, but the symmetry is broken. and there’s many things in the universethat are like that. the fundamental laws are symmetric, but the actual universe we live in has broken. >>neil degrasse tyson: so, we can’t lookfor weirdness because if it is a program that’s running,

which came up earlier, and we’ve all hadprograms that crashed, what happens if our program crashes? do we all disappear likeinstantly? what are the consequences to this being aprogram if someone unplugs it, if there’s a bug that crashes the entire system? is there any piece of the universe where thatpart of the program failed? >>david chalmers: i have it on good authority[unintelligible 79:24]— >>max tegmark: a big spinning wheel here onthe stage going round and round and round. >>david chalmers: i have it on good authorityit’s crashed five times during this panel discussion,

but, fortunately, it rebooted perfectly andwe have no memories of it. that’s just good error correction. >>james gates: no, no, but, neil, the pointyou raised, in fact, is for me one of the most uncomfortable ideas about the simulationhypothesis. that it’s running on some device, and thatthe errors would then—how would it manifest itself? well, in the way that i think most of us thinkabout it, it’s kind of the end of the universe. and, for me, the universe that i have studiedfor 50 or 60 years is a kind of a—it’s a place of mystery,

but it’s not a place of the fundamentalkind of insane, unleashed chaos that kind of end. now, we know that—we talk about, for example,false vacua. that’s something, again, that lisa knows a lot about because it was pioneeredlargely by sidney coleman, a professor at harvard before lisa got there. we know that these possibilities are out there,but the breaking of the symmetries are so— one thing that’s really odd about this isif you don’t break the symmetries you don’t get us. you don’t get a universe with creatureslike us in it unless you break these symmetries. and so maybe the question we should—

>>lisa randall: [unintelligible 80:46] whydid i break those symmetries? >>james gates: that’s right. the simulation’slike why am i breaking those symmetries? so, the fact of our existence says somethingvery deep about the mystery of this place we call the universe because the laws—thesymmetric laws, they’re beautiful. we write them with simpleequations on one or two lines. but if those laws held exactly, we’re nothere. >>neil degrasse tyson: in fact, it’s justa universe of photons. >>max tegmark: i think that’s a very goodpoint you bring up there. at first, it looks like if someone’s simulatedthis, they have been drinking too much or

whatever, or really wasteful because you might ask why—ifthey just wanted to simulate us, did they bother simulating all this dark matter? sixtimes as much matter, obviously, increase their cpu cost, what they had to pay for theirã¼ber cloud services, whatever. who needed that? >>neil degrasse tyson: plus we came reallylate in the universe. >>max tegmark: but every single thing we’vediscovered, like dark matter, for example, that seems superfluous, we’ve since discoveredthat if it weren’t there we would be dead. or, in fact, we wouldn’t even have evolvedin the first place.

if there were no dark matter, for example,then its gravity would have not been there to help pull our galaxy together, and the milky way wouldn’t even have existed. so, it’s an interesting question, i think,to ask is this the simplest kind of simulation you could run that would actually get someinteresting life? or is there something in our universe, whichis really just bells and whistles that you could optimize out? >>david chalmers: someone was just doing—thiskid was just doing a science experiment.

he ran a million simulations overnight, andexactly one of those universes produced— broke the symmetries in the right way to produceconscious beings and, hey, here we are. >>lisa randall: why did they make [unintelligible82:28] so difficult to simulate on the [unintelligible]? >>james gates: that’s a scientific question,guys. >>neil degrasse tyson: so, zohreh? yeah. >>zohreh davoudi: so, maybe just adding somethingto this. if someone was just looking at the weirdnessthat we observe in the universe, maybe more fundamental question to ask— again, we can ask why the parameters of ouruniverse, mass of the electron or the cosmological

constant and things like that, why should they have the value they have? in terms of the simulation scenario, you cansort of start to think this is just an input as many other input. or the other way to interpret it is that wedon’t know, at a fundamental level, what’s going on. maybe there is embedding theorythat would arise to— that is simpler. it has fewer input, or maybejust one, and then gives you the values of the standard model and all these theoriesthat, no, to be exactly the same that we observein nature.

>>neil degrasse tyson: well, just to be clear,when we—if any of us program a computer, a simulation of anything, there’s a setof parameters that are established up front. and then you watch what happens thereafter,and then you sometimes tweak the parameters if necessary. some other parameters are non-tweakable. almostall of our codes, there’s a line that gives the value of pi that’s not tweakable. >>zohreh davoudi: we don’t have any mathematical—sorry. >>max tegmark: my sons tell me, for example,that in minecraft when you create a minecraft world,

i’m taught by philip and alexander, youhave to input a world seed. >>max tegmark: yeah. and if you put in a differentone, different universe. >>zohreh davoudi: basically, it means thatwe don’t have the mathematical equations, for example, to say that the mass of the electronshould be what we measure and things like that. so, we don’t haveyet a description as why these have these values. >>neil degrasse tyson: but why should we be—thismight have to go back to david. why should we be the measure of what an intellectis, and then judge what is hard or what is easy?so, in other words, just because we think

something is hard because of all of thesephysical constants that come together, so that we exist many billions of years afterthe universe forms, maybe that’s just trivial for anybody who’s programing the universe. >>david chalmers: yeah, i mean, it probablyis trivial. they’re probably got sim universe technology. everyone’s running it on their desktop,[unintelligible 84:48] google in the next universe up. >>neil degrasse tyson: the next universe up.that’s now a phrase. >>david chalmers: create a sim universe by,okay, set a few parameters around the universe.

no big deal. some of those universes produce nobody. someof those universes produce somebody. and those somebodies have to reverse engineertheir universe, and it turns out reverse engineering is reallyhard, whether you’re in a simulation or not. but that’s just—if you look at it thisway, it’s just a matter of perspective. >>neil degrasse tyson: because when i thinkof the game tick-tack-toe, to a child this is a challenging game. they don’t know what move to make next,and then they might win or lose, and then

they cheer, or they’re sad. and then you realize this is a pointless gameyou can play so that you’ll never lose, or win. but then it’s no longer fun. but to a child, it is a complex—it’s agame that challenges them. and then we have the game of chess, which challenges us, but you go up an intelligencelevel, and then it’s just a trivial exercise. i don’t care how many possible moves thereare. it’s trivial if the brain is a greater brain than ours. and i’m reminded, which one of you may remember—justto correct me if i don’t get it right—

was it feynman who first analogized the lawsof nature to our attempt to understand the laws of nature would be like coming upon a game of chessand you know nothing of the game, and you’re just watching people move, and you don’thave the rule book. and you have to deduce what the rules are. and so pretty easily you can see, well, thispiece moves this way and this only goes diagonal. you get that, but occasionally one of thepieces jumps two squares instead of just one. well, why did it do that? so, you make a noteof that, right? and then later on that little piece that jumped too,

it reaches the other end of the board, andthen it becomes a whole other piece. that’s kind of freaky. it’s rare, but it happens, and it’s animportant rule of the game that most of the time you don’t see. and so i’m left wondering how much of achess game, without the instruction manual, is the very universe in which we live. to get your answers one each from that. yes,zohreh? >>zohreh davoudi: [unintelligible 87:04]— >>neil degrasse tyson: all right, david, youled off with that.

>>david chalmers: i would say that’s basicallythe situation we’re in. we call that—this is the game of reverseengineering the universe, and we call it science. a little bit for philosophy, too. there are clues we could get about the—wecertainly get the equations and so on, but, hey, there are clues we could get about thegrander structure. hey, maybe at a certain point we’re goingto find one of those constants that has an arbitrary value, and find there’s a coded message in therein the simplest possible language saying, yeah, you guessed right.

it’s a simulation. if so, then that’s part of the reverse engineering,too, but it’s actually a miracle we can understand anything about the world we’rein from this perspective. the world could have so much complexity, whichis completely beyond us. and it could be that we are simply scratching the surface. but i think to do science, you’vejust got to take the optimistic. >>neil degrasse tyson: but you left me verydisappointed earlier in saying that anything— i was trying to find evidence to show thatwe’re not, and that evidence that we’re not could beput in by someone who is.

>>david chalmers: yeah, i’m afraid— >>neil degrasse tyson: so, that was disturbing.so, i’m getting back to zohreh’s point. what’s the point of thinking that way? >>david chalmers: well, you might take on[unintelligible 88:24] ockham’s razor, which is if we don’t need the hypothesis thatwe’re in, a simulation, then we should just do withoutthat hypothesis. maybe science is going to tell us a bunch of math. it’s a bunch of equations. yeah, that couldbe combined with the further hypothesis we’re in a simulation.

it’s a lot simpler if we’re not. so, ockham’srazor at least says why bother. then, on the other hand, you’ve got bostrum’sstatistical argument. we might actually produce a whole lot of simulations, and have very a good reason to believe thereare a lot of simulations in the universe, at which case you can just raise the question. we know some people are in simulations. wecannot assign at least probability of zero to us. at that point it becomes a statistical question. so, i think the standard scientific reasoningof ockham’s razor might give some reason

to reject it, but the statistics starts to maybe balancethat [unintelligible 89:15] around. at a certain point, you’ve got to start doing some math about the probabilities. >>neil degrasse tyson: so, ockham’s razoractually goes very far back, i think, to the 14th century, where it was the earl of ockham who suggested— >>david chalmers: william ockham. >>neil degrasse tyson: —that of all explanations,perhaps the simplest has the best chance of

being correct. and that was well before the methods of thescientific method and others. so, we’ve been using it an invoking it ever since. so, lisa, is the universe a chess board andwe’re— >>lisa randall: so, i was very much with youuntil the very end. so, i think it is indeed true that we don’tknow the answer, and we’re just going to keep doing science until it fails. and it hasn’t failed yet. seems to—wemake progress, and so we’re going to keep doing that.

in terms of are we trying to figure out, iactually love the idea that we’re a simulation where they actuallykind of saved in efficiency by making us not quite smart enough to figure all this stuffout. >>lisa randall: so, [unintelligible 90:18]a lot of it. >>neil degrasse tyson: that’s a built in— >>lisa randall: but, really, that’s toomuch computational power, so let’s make them a little bit dumber. but i do have—i understand it’s a possibilitythere’s a simulation, but there is a problem with the statisticalargument. i mean, i think if you asked any

statistician, there’s just not based on well-defined probabilitieshere. and actually one of the key—so, bostrum’sargument would say that also that you have lots of things simulating, lots of thingsthat want to simulate us. and i actually really have a problem withthat. why simulate us? i mean, there’s so many things to be simulating. none of us actually get together and say—imean, we simulate processes or whatever, but we mostly are interested in ourselves. i don’t knowwhy this higher species would want to bother

with us. >>max tegmark: maybe they don’t care aboutus. they just simulate a bunch of physics, or a bunch of laws. and, hey, we came alongas a by-product. >>lisa randall: yeah, it’s in the realmof possibility. >>neil degrasse tyson: so, we grew out oftheir petri dish. >>lisa randall: but i do think that, again,ultimately what—as physicists, as scientists, we’re interested in the things that we canactually test. so, to the extent that it gives us an incentive to ask interesting questions like do we seecosmic rays at different energies,

or from different directions, going at slightlydifferent speeds, or anything of that nature. or do we find the laws—i mean, that’scertainly worth doing to see what is the extent of the laws of physics as we understand them. but that is what we’re doing anyway, butmaybe we’ll frame—maybe we’ll be presented with a bunch of other questions. but that is—i mean, so it’s a little bitof a systematic way of figuring out the chess game because in the case of the chess game, you have manygames. you can watch many games. here, we have this one universe, and we cantry to make little tests within that universe

to try to test laws, but those apply in thoselittle realms. i mean, one of the brilliant things aboutgalileo was he realized there’s many ways to do science. there’s plot experiments, observations. but he actually came up withthe experiments themselves. [unintelligible 92:15]— >>neil degrasse tyson: we were bringing himto the next panel. >>lisa randall: yeah, i know. i know. i’mtotally excited about that one, too. so, that’s just the nature of science. so,i think we are trying to figure it out to the extent that we can.

>>neil degrasse tyson: jim? >>james gates: i think you nailed it withthe chess game analogy. one thing that i think that a lot—oftentimes, when i talk to people—and lisa alluded to this very well, is that a lot of peoplethink it’s all about them. they really do. they think it’s all aboutthem. they have to understand things that’s somehow related to them. it’s all about them. and i think that oneof the things that science actually teaches us is that it’s not all about us. we may be struggling with the descriptionthat we’re trying to construct, but the

universe doesn’t care whether i understandor don’t understand. the universe doesn’t care whether i existor not exist. the universe, at least as i have studied it, is i’m going to retreatinto einstein, and at the end of the day it is an extraordinarymystery. that’s the sense that i get from having studied science for now 50 years almost. that we live in this place of mystery, andwe need to accept a humbleness about our efforts to go out and explain that chess game that you described. >>neil degrasse tyson: ooh. max?

>>max tegmark: i fully agree with you thatthe world would be a better place if we humans could be a bit more humble. at the same time, i also feel that the verysoul of physics is this audacity to look for hidden simplicityin things. so, i think the metaphor of chess is a beautiful one. we have as a goal in physics to look at thisvery complicated [unintelligible 94:00] universe and look for hidden simplicity, look for rulesof chess, which are actually simple. not the list of one googleplex different possiblethings. we’re not just saying it’s all random.

and, of course, we don’t know yet whetherthere are rules that are simple enough that our human minds can understand them or not. but i’m an optimist, and i feel it’s actuallymuch healthier as scientists if we have this innate optimism instead of saying, well, it might be theywere too dumb to ever figure this out, so let’s just not try. i think it’s much healthier to say thereis a real possibility that there is this hidden simplicity, and, in fact, galileo and einstein and somany before us have found simplicity far beyond

what their ancestors every dreamt to. so, let’s keep looking for even more hiddensimplicity. maybe this is actually all computational mathematical,which that’s anyway the ultimate audacity to hope for that because that would mean thatin principle, at least, it really is possible to figure out the rulesof the game. that’s that attitude i’d like to take.consider the possibility that it is possible, and then try our very, very best to actuallyfigure it out. >>neil degrasse tyson: thank you, mario, forthat and, morpheus. so, zohreh? >>zohreh davoudi: so, yeah. i would like todeviate a little more from your question very

quickly because it didn’t came up in thediscussions, but i wanted to distinguish between the ideathat we can simulate a universe, as opposed to the universe being a simulation, because there are fundamental limits to ourcapacity to actually compute things. and these are based on the physical laws thatgovern our universe. basically, we can’t have infinite power, the energy, the lawsthat govern [unintelligible 95:56] uncertainty principlecan limit the right that we can process logical operations, and also the entropy and thermodynamiclaws can limit the amount of memory that can hold in a givenamount of the space-time.

and thanks to ideas like this that were discussedby [unintelligible 96:14] and other people, and therefore we might not be able to actually—andthere are other actually limits when you think about larger-scale expansion of the universe, whether or not it can ever casually connectto parts of the universe. it’s expanding. and, therefore, store and process those information to be able to actually re-simulate the universethat we have. so, it’s a different idea. i don’t thinkthat based on the physical laws of our nature this could be possible, but that doesn’t mean that our universecould not be a simulation inside another universe

that has another laws of physics that doesn’t actually limit the amount ofcomputation that is required to simulate a universe. so, these are two different ideas. but just to come back to your question, ithink as a physicist and thinking about the simulation idea, i think it doesn’t change the way i thinkabout the science, and i do my every day job as a scientist. i think just the notion of whether or notwe’re real or just simulated, it’s kind of irrelevant because what we are observingis no different from being real or imaginary.

we just go and discover things that we alreadydon’t know about the universe, that laws that we haven’t discovered. but at some point, maybe we findsome sort of more strong evidence that could connect us to a higher level that says something about whetheror not the universe is computational based and there is some simulator besides us. these are the ideas that require more thinkingand more thinking out of the box, i would say, at the moment, but maybe at some point in future when wehave more understanding of the laws of our

universe, we can have more rigorous way to go and lookfor those evidences and say something meaningful. at this point, there is not such evidence.we’ve just started to make assumptions by just comparing our simulations of the universeand see what would be the consequences of those kindof assumptions. but at the moment we don’t have such evidence, and it would be wrong to put a lot of focuson this idea. but it’s definitely a very fun and curious idea to think about as a scientistand, therefore, i think that’s why i do science.

>>max tegmark: i just have to alert you sheknows the answer to your chess question, and she’s just not telling us because you’repersian and you persians invented chess. >>zohreh davoudi: yeah. i actually playedthat game when i was very, very young. >>neil degrasse tyson: so, she does have theanswer. so, let me just end before we transition toq&a. i want to get the likelihood that you think we are in a simulation. ten percent chance? twenty percent? just giveme a number. just a number. go. >>zohreh davoudi: i can’t give you thatnumber. i don’t have any answers. >>neil degrasse tyson: no.

she’s not authorized to divulge that information.okay, so you’re giving no answer. max? >>max tegmark: seventeen percent. >>neil degrasse tyson: seventeen percent. jim? morpheus? >>james gates: one percent. >>neil degrasse tyson: one percent chance. >>lisa randall: i’m going with effectivelyzero. >>neil degrasse tyson: effectively zero. david? >>david chalmers: forty-two percent.

>>neil degrasse tyson: i think the likelihoodmay be very high. and my evidence for it is just it’s a thoughtexperiment, and it’s simple. we’ll just end with this reflection—andi’m elsewhere like on youtube saying this, so you can check it out later, if you choose. i just think when i look at what we measureto be our own intelligence, and we tend to think highly of it, getting back to jim’s point, there’s acertain hubris just even in how we think about our relationship to the world. and that’s understandable perhaps, evenin the search for intelligent life in the

it comes with the assumption that we’llfind life that also thinks we are intelligent. well, if we look at other life forms on earthwith whom we have dna in common, there is none that we would rank ever in thehistory of the fossil record, or life thriving today, that we would rank with us and our level ofintelligence. so, given our definitions, we’re the onlyintelligent species there ever was because we have poetry and philosophy and music andart. and then i thought to myself, well, if thechimpanzee has 98-whatever percent identical dna to us—

pick any animal. it doesn’t matter. dogs,it doesn’t matter. mammals have very close dna to us. they cannotdo trigonometry. some people can’t do trigonometry. certainlynot these animals. so, if they cannot do trigonometry, and they have such close genetic identityto us, let’s take that same gap and put it beyond us and find some life form thatis that much beyond us that we are beyond the dog or the chimp. what would we look like to them? we wouldbe drooling, blithering idiots in their presence. the smartest chimp can do maybe some signlanguage and stack boxes and reach a banana, put up an umbrella, like our toddlers cando.

our toddlers do that. so, maybe the smartest human—bring stephenhawking forward in front of this other species, and they’re chuckling because they’llsay, oh, this happens to be the smartest human because he’s slightly smarter than the restbecause he can do astrophysics calculations in his head, like little timmy over here. oh, you’re back from preschool? oh, you’vejust composed a symphony. that’s so— let’s put it on the refrigerator door. wejust derived all the principles of—oh, that’s cute. and so that is not a stretch to think about.and if that’s the case, it is easy for me

to imagine that everything in our lives isjust the creation of some other entity for their entertainment. it is easy for me to think that. so, whateverthe likelihood is: zero percent, 1 percent, 17, 42, no answer, i’m saying the day we learn that it is truei will be the only one in the room saying i’m not surprised. thank you all for coming tonight, and thankthe panel. we will bring up the lights, and in this transition between the formalpart of the panel and the q&a that we’ll

be taking from you, i just want to tell you what it takes to runthis thing. as i told you earlier, it was formed by anendowment created by isaac asimov’s widow, janet asimov, and friends of isaac asimov. and we’ve been going strong ever since.and so i just want to say we have people who run this thing. we have susan morris, who’s director ofhayden programs. we have susan. susan is out there.

and we have emily [unintelligible 103:41].she’s also part of this team that make this work. we have my executive assistant, elizabethstachow. we have laura jean checki, who’s our stagemanager. we have some fans of laura in the audience.good. we have miriam poser, who has been with uslike forever and is a die-hard supporter as a volunteer of our programs. lydia marie petrosino—did i pronounce thatright, lydia? i only ever call you lydia marie. lydia marie is good. and, of course, we havebetty walrond.

these are people who make this happen everysingle year. i just want to collectively give them applause. we have about 15 minutes for q&a, so let’sgo straight to it. we’ll go back and forth, left and right. no one will hear you unless you speak intothe microphone, so let’s start here. let’s go. >>question: okay. so, my question is doesit really matter— would you view the universe differently ifwe knew it was simulated? could we do the math differently?

>>neil degrasse tyson: ooh, i like that. tomake this efficient, we’ll pick one person to answer, so how about max because your book is tilted—what’sthe title of your book? >>max tegmark: our mathematical universe. >>neil degrasse tyson: yeah. so, he’s theguy to answer this question. okay. if you knew, would your math be different? >>max tegmark: well, i’ll take your question.i mean, if i knew, would that make me super depressed or super excited? would it change the way i feel about everydaylife? my answer is absolutely not.

i feel that when we look at these rather sterileequations or the computer code, or whatever it is that’s running this, there’s no meaning or purpose built intothat. we shouldn’t look through our universe creating the meaning for us. it’s we who give meaning to our universe.so, the way we feel about things, and the meaning we create, is the same regardlessof whether we’re simulated or not. and i think this is very much the point that davidwas making earlier also. we shouldn’t diss things just because they’resimulated. >>david chalmers: the math is a little bitdifferent if we’re simulated, on the other

hand, because there’s also the math of the simulatinguniverse. >>max tegmark: right. >>david chalmers: there’s a math of ouruniverse embedded in a bigger one, which raises some exciting prospects like,hey, maybe we could get out and explore that one. so, that would be cool. >>neil degrasse tyson: wait. so, you’reswaying—can you embed a complete system of mathematics within a higher system of mathematics? >>david chalmers: yeah. maybe the embeddinguniverse is a vastly higher level of complexity

than ours, in order to have the computational power,for example, to simulate ours. maybe they’ll let us out one day. we’re just computers in their world. they’llgive us input devices. >>neil degrasse tyson: so, you feel like you’rein prison? >>david chalmers: no. it’s just like earthis cool, but the galaxy’s even cooler. yeah, a quick one here. >>lisa randall: i think it would feel different. it’s always interested me that if you missa basketball game and you know it already

happened, it’s less interesting to you to watch, eventhough you know it happened already because it’s not happening in real time.and you might not even know the result, but i think there is a sense in which psychologically the idea that it is preprogrammed would bedisturbing, at least to me. >>neil degrasse tyson: my analogy to thatis if you go to the smithsonian air and space museum in washington, and you see the apollo 11 command module thatwent to the moon and came back, and there it is,

if you made an exact replica of that and putit on display anywhere else and say you cannot really tell the difference except microscopically, but it’s a fake, it means—it’s differentto you even though you can’t tell the difference. the knowledge that it’s really seems tomatter to us than if it’s a simulation or a model, inthat case. so, i have to agree. i reluctantly agree.i don’t want to agree, but i have to agree. >>james gates: i disagree for one reason.i don’t do science to make me feel something. i do science because i think it’s an investmentin the long-term survival of our species. our science underlies our technology.

if our environment changes, we will use thattechnology to survive, whether that’s true if we’re simulationsor not. that’s why i do science. >>neil degrasse tyson: are you also runningfor president? >>lisa randall: no, because they can’t talkabout science. >>neil degrasse tyson: who, by the way, jimgates is on the president’s committee of advisors of science and technology, pcast. and you’ve been there for almost the entireadministration, so keep up the good advice that you’re giving. let’s go right here. hey, how are you doing?

>>question: good. >>neil degrasse tyson: what grade are youin? >>question: eighth grade. >>neil degrasse tyson: eighth grade, cool.so, what do you have? >>question: so, you were saying about bugsin the code of the universe, if it is a simulation. how come if it probably statistically wouldnot be perfect, how come we have not so far seen any corruption or glitches maybe in the far-lookinglike the cosmic background radiation? how have we not seen anything that just seemslike it couldn’t be there?

>>neil degrasse tyson: great question. jim,what do you got? >>james gates: that’s an easy one to answer. up until september of last year we have neverseen gravity waves either. the point is that our technology was not sufficient, and might not be sufficient now. so, what he’s saying is that it may stillbe there. we just haven’t found it yet. that’s a cop-out answer, i think, betweenyou and me. but don’t tell him that i said that. yes, zohreh? yes? >>zohreh davoudi: yeah. so, exactly the lineof investigation that we have in our favor

is whether or not the simulation is imperfect,as you say. so, given that we haven’t already seen somethingdoesn’t mean that we might not see something and, therefore, as i said, we look for evidencesthat tells us that there are some imperfection in the universe because the simulator or the amount of computation that could bedone to generate our universe has been finited, [unintelligible 109:54] infinite and, therefore, there might be some evidence. butit doesn’t mean that the fact that we haven’t

seen it doesn’t mean we shouldn’t go andlook for it. it’s been difficult, but— >>james gates: but i thought the questionwas why haven’t we seen it. that’s what i answered. >>neil degrasse tyson: well, yeah. and don’tyou both agree? you’re saying if you haven’t seen it,it doesn’t mean it’s not there. keep looking. >>james gates: absolutely. >>zohreh davoudi: right. >>neil degrasse tyson: good. i’ve got aquestion from twitter

that came in. [even quinter] from the twitterverseasked, “i think i’ll direct this to max. if the universe is a simulation, does thatmean there’s a limit to how far our universe can reach?” because we speak of an infinite universe beyondour horizon all the time. so, you’re ready to say if it’s a simulation, it can’tbe infinite, and there is the limit to the code. >>max tegmark: it’s a great question. ifwe are being simulated in one universe up on finite computational resources, yeah, then either the size of our universeis actually finite, or there’s some other

trick like it just keeps repeating itself over andover again. >>neil degrasse tyson: like the backgroundin the flintstones when they’re riding in the car? >>max tegmark: precisely. >>neil degrasse tyson: the background justrepeats. i was so angry. i said you can’t draw me a—what’s withyour budget? >>max tegmark: that’s right. >>neil degrasse tyson: have you ever seenthe backdrop of cartoons when people are running?

it just repeats. when i was a kid, that disturbedme. >>david chalmers: maybe it’s a just-in-timesimulation. it’s kind of like the truman show or something. they started off simulating me in australiawhere i was born [unintelligible 111:25]. i came to new york, so suddenly i had to simulateall of you guys and— >>neil degrasse tyson: for you? >>david chalmers: yeah, exactly. or for whoever.or maybe they started off with the earth, and then we go to— the voyager just reached—the thing justreached pluto, so now they had to simulate

pluto. >>neil degrasse tyson: i see. >>david chalmers: just like that. so— >>lisa randall: let’s not start with pluto. >>david chalmers: start small and go bigger. >>neil degrasse tyson: yeah, don’t get mestarted on pluto, first of all. but what you’re saying is they might justbe laying down the bricks in the road as we drive along. >>david chalmers: yeah. just-in-time simulation,they call it.

>>neil degrasse tyson: just in time. >>david chalmers: yeah. simulate only as muchas you need. >>neil degrasse tyson: okay. right here. yes? >>question: hi. so, we briefly discussed infinityand how it relates to this topic. but i was just wondering on the other endof the spectrum why is nothing not a thing? is there not nothing when you come down tothe fundamental question? >>neil degrasse tyson: we had an entire asimovpanel on that very subject. where were you? the title of that was the existence of nothing,and we had all the experts on nothing on the stage at the time. i’m just saying.

so, okay, maybe he didn’t know that, so— >>lisa randall: i actually have a probabilisticargument. >>neil degrasse tyson: okay. so, we’ll entertainit, but go online. the whole thing is there. it’s called the existence of nothing. okay,yes? >>lisa randall: so, in my book dark matterand the dinosaurs i have a section on cosmology, and i actually talk about the probabilityof nothing. and i think nothing is just very unlikely. i mean, first of all, we wouldn’t talk aboutnothing because we wouldn’t be here. but nothing is just one—

if you think of a number line, zero is justone point on it, and nothing is just—i would say it’s veryunlikely. and if you have an explanation of why there’s nothing, then there’s something there that allowedyou to have the rules to explain it. >>neil degrasse tyson: so, you’re sayingthe act of posing the question of why there’s something is proof that there could not havebeen nothing? >>lisa randall: right. so, there’s two answers. >>neil degrasse tyson: okay. crystal clearnow. >>lisa randall: that’s one. and the otheranswer is probabilistic.

>>neil degrasse tyson: okay. yes, sir? >>question: hi, neil. how are you? >>neil degrasse tyson: hi. good. >>question: so, i think i’m going to saythis every day now after this. i’m going to say computer end program when i wake upin the morning. but the question is say we assume that weare in a simulation—we don’t try to prove it anymore— would it be possible to come up with equations,knowing what we know from the past, to predict what inputs might be in the future,

assuming that this is an original idea andit’s not an input from the programmer and we’re not on a holodeck within a holodeckwithin a holodeck within a holodeck. you think that would be possible and maybeescape the simulation? >>neil degrasse tyson: david, what do youhave? >>david chalmers: well, i think we’re probablystuck for now with the laws of the actual simulation of the simulated universe. if it’s a perfectsimulation, we’re not going to be able to do better than that. we’re not going toget information about the character of the simulated universe.

now, if it’s a buggy simulation, or if it’sinteractive simulation—if they’re sending messages down here in the way that god wassupposed to and so on— then all bets are off. all i can say is sofar i’ve not seen evidence that we can use to make predictions, hey, tomorrow the simulatorsare going to call the whole thing off. so, all we can do there is speculate as faras i can tell. if zohreh’s work pans out, maybe we’llsuddenly have a lot more evidence. >>zohreh davoudi: and i would add that atthe end of the day we are living in this universe. so, we are constrained by the laws of thisuniverse. so, the concept of escaping from this universe

doesn’t seem logical to me because we arebound to be evolving according to the laws of this universe, and not something beyond that. >>neil degrasse tyson: plus, some other universeshave slightly different laws of physics. i don’t want to be the first to visit them. send something else then, and we’ll figureit out. we only have time for a couple more questions, one of which i’m going to takefrom our twitter list. so, let’s go right here. sir, yes? >>question: sorry, neil, i tend to disagreewith your conclusion about the universe simulation

percentage, and more agree with lisa’s zero percentage.here’s why. using your chessboard analogy, yes, thereare 64 pieces on a chessboard. you can assign numbers to each piece. >>neil degrasse tyson: sixty-four squares. >>question: sixty-four squares, right. andyou can assign values— numerical values to the chess pieces, andthen use computers to see into the number applies: 3, 4, 5, and then run the simulation, and you get theend result of who’s going to win and so

forth. however, just look at the humans on this earth.we have seven billion people now on earth, and even if we can mathematically model oneperson, when we have interactions of each other, we have interactions of more than eachother because every action there’s a reaction,and then we have seven billion people. so, the result is going to be totally unpredictable.in fact, it doesn’t look too good because the earth’s with its limited resources, and the earth population growing at a logarithmicrate. >>neil degrasse tyson: exponential rate.

>>question: the conclusion—exponential rate. >>question: it’s going to be one conclusion,and that is—the result is not going to be >>neil degrasse tyson: but it may be thatthese multiple interactions that transcend our native ability to compute are no different from the tick-tack-toe gamebeing played by the five year old. we’re just too stupid to know. >>question: well, that’s true. >>neil degrasse tyson: okay. that’s right. >>question: but, again, when you look at thecomplexity and try to mathematically model

seven billion people’s characteristics— >>neil degrasse tyson: yeah, we can’t doit because we just have human brains. >>question: absolutely. thank you very much. >>neil degrasse tyson: yeah, sure. forgivethe rest of the people online. the last question is going to have to be from our twitter streamhere. and this one i’m just going to send to lisa.lisa, you will take us out with your answer to this question. this is from ashley [cannino], “is darkmatter—there are multiple ways you could probably get to this, but let me say how it’swritten,

“is dark matter transparent where simplyrules of the game a computational structure?” like an operating system. and think of dark matter and dark energy,these permeating elements of the universe that we don’t understand at all. we don’t know what’s causing them, butwe can measure their existence. could that be the blood of the operating system throughoutthe universe? >>lisa randall: so, it’s an interestingquestion, and people have asked that question. and you have to take a little bit of an ockham’srazor approach here. so, first of all, dark matter is indeed transparentmatter. it’s matter that just light just

goes through. there’s evidence for it not because we seeit, because it doesn’t emit or absorb light, but because it has gravitational influence.and we can observe the gravitational influence. now, you can ask is that because we got thelaws of physics wrong and there really wasn’t matter, and the we got the laws of physicswrong. first of all, it’s a lot simpler to believethis matter that we have no reason to believe shouldn’t be there is there, than to think we got the laws of physics wrong.because the laws of physics work incredibly well

over many distant scales. so, there’s noevidence that those laws of physics are wrong. but, furthermore, there’s actually—there’smore and more evidence that makes it look just like it’s matter. one of the things is known as the bullet cluster,or other clusters, which are really mergers of clusters of galaxies.clusters of galaxies are bound states of many galaxies [headed] together. and when those things go through each other,a cluster of galaxies has gas in it and it stores in as dark matter. when it goes throughit, you see the gas get stuck in the middle. you can see that through x-rays. through gravitationallensing, you can see the dark matter just

pass through. it acts just like you would expect matterthat’s not interacting to act. it goes right through, the gas stays in themiddle. now, you can try to mock up equations, or some simulation or something that doesthat, but it looks just like matter would look. it’s exactly what you would predict. >>neil degrasse tyson: except we establishedearlier that we don’t form our own galaxies without the existence of dark matter creating the womb in which we collect. so,isn’t that kind of like an operating system, enabling matter to do its thing?

>>lisa randall: well, gravity is, in somesense, the operating system. but gravity is responding to the existence of the dark matter. and dark matter does play a big role. there’smore of it. it collapses. it doesn’t attract with light, so it can form structures more easily thannormal matter. >>neil degrasse tyson: i like that. gravity’sthe operating system. well, how about dark energy? >>lisa randall: dark energy is another justthing that’s in there that’s responding to gravity.

so, dark energy is—for those who don’tknow—smoothly distributed. it’s not like matter that clumps together. >>neil degrasse tyson: it’s the operatingsystem. >>lisa randall: it’s not the operating systemeither. >>neil degrasse tyson: operating system iseverywhere you touch on a computer. so it dark energy. >>lisa randall: i’m just getting confusednow. it’s part of what i put in, at least inmy initial state, and then i let the gravity equations work on it.

so, you have this distribution of energy.you have this distribution of matter. and then you can ask what is the effect ofthis energy that we don’t observe directly. in some sense, we observe the fact that itis responsible for the acceleration of the expanse of the universe. but gravity is the only law there. the otherstuff is just stuff. dark energy is stuff. dark matter is stuff. the gravitational equations are acting onthat, and it’s actually creating the gravitational [force]. >>neil degrasse tyson: well, so if gravityis the operating system of the universe,

i can’t wait for universe 2.0. thank you all for coming this evening. thankthe panel. zohreh, max, jim, lisa, david. >>max tegmark: it was so much fun. >>zohreh davoudi: thank you. >>max tegmark: that was really— >>neil degrasse tyson: thanks for coming out.that concludes the 17th annual isaac asimov panel debate. good evening to everyone watching live stream.goodnight to you all here in new york. we’ll

see you next year.[end of audio]