2016 Isaac Asimov Memorial Debate: Is the Universe a Simulation?

>>NEIL DEGRASSE TYSON: Welcome back. This
is the 17th Annual Isaac Asimov Panel Debate. And we’ve been going strong ever since the
year 2000, when an idea surfaced in the hearts and minds
of the family of Isaac Asimov, exploring a way for his memory to be preserved in the programs of
this institution. And Isaac Asimov was a friend of the American Museum of Natural History. Much of the research for so many of the books
that he wrote took place in and around the halls and in our libraries. And so perhaps
there’s no more fitting tribute to him and to his memory, than to
keep this celebration going. So, thank you for attending. We are also streaming live on the Internet.
And I’m your host for this evening, Neil deGrasse Tyson. I’m the Frederick P. Rose
director of the Hayden Planetarium. [APPLAUSE]>>TYSON: Just a couple of newsy notes. This year we sold out in three minutes. And
it’s not a particularly sustainable model. So, we’re going to have top people looking
at how to improve that next year. We don’t know how yet, but the least we
can do is offer it live streamed on the Internet on amnh.org. So, I welcome everyone from the Internet universe, as well as the
universe gathered here. Tonight’s topic is: Is the Universe a Computer
Simulation? Yeah. [LAUGHTER]>>TYSON: Do you want it to be a computer simulation? I mean, this topic is—we’re going to—you’ll
see. We’ve got some highly thoughtful, talented, respected people to weigh in on this. I will
introduce them individually, and then we will start the panel. By the way, unlike most debates you might
have heard about or read about, where there’s point/counterpoint and an argument is presented
and attacked, that’s not what’s going to happen here.
We’re using the word debate loosely. Think of yourself as eavesdropping on scientists at a break-out room in a conference
on this topic. So, we’ll all be sort of arguing with one another, and you’re listening
in. That’s really what’s going on here. And you get to see how scientists think. You
get to see how arguments are contested. You get to see how resolution arrives, if
it arrives at all. So, afterwards we will have a brief time for
question and answer before we adjourn before 9:00 Eastern time zone—Eastern daylight
time. So, join me in welcoming my first panelist
this evening. He is a professor of philosophy at New York University, where he’s also
director of the Center for Mind, Brain and Consciousness, David Chalmers. David, come
on out. [APPLAUSE]>>DAVID CHALMERS: Hey. Looking forward to
this.>>TYSON: Thank you. Next we
have a nuclear physicist, who’s a post-doctoral research associate at MIT up in Cambridge, Massachusetts. And let’s
give a warm welcome to Zohreh Davoudi. Zohreh. [APPLAUSE]>>TYSON: Next, we have someone who is actually no stranger to this panel. This may be his third visit to it. In part, the topic of this year was selected because he brought it up a couple
of years ago. And I said, man, we could do a whole subject on that alone. Let’s give a warm welcome back to James
Sylvester Gates. [APPLAUSE]>>TYSON: Another non-first timer is professor of physics up at Harvard, a specialist in nuclear particle physics.
Give a warm New York welcome to one of our own, a graduate of Stuyvesant High School, Lisa
Randall. [APPLAUSE]>>TYSON: Did I do this out of order? No, we didn’t.
Good. And last among the five—yeah, I did do it
out of order. My bad. Yeah, sorry. You guys know where you need to sit. Talk among yourselves
while I do this. There’s a friend and colleague, an astrophysicist,
also from MIT, who’s done some deep thinking about this
very subject and has even written a book on the topic. Let’s give a warm New York welcome to Max Tegmark. [APPLAUSE]>>TYSON: By the way, we are lit for live streaming.
And the intensity of the lights on the stage is such that two of our panelists—I think they just want
to look cool, but they said they need to wear sunglasses for this event. And that’s cool.
Later on I might join you. I brought my pair with me as well. If I’m feeling cool I might do just that. So, Zohreh, I’d like to start with—no.
who should I start with here? Yes, let me start with you, Zohreh. Could you tell me why this topic interests
you? Just give a couple of minutes just as an introduction here.>>ZOHREH DAVOUDI: Sure. So, as Neil said,
I’m a theoretical physicist. My interest is in nuclear physics. In fact,
I got my PhD in 2014 from Institute of Nuclear Theory in University of Washington. And the research I was focused on there, and
at the moment, is trying to use the knowledge of the laws of nature and, in particular, strong interactions to start
from a bottom-up approach and try to see what comes out in a physical system. And that’s actually relevant to why I got
interested in the simulation idea. And, in fact, by just watching the progress that researchers
in this field of simulating a strong interactions have made in several past few years, we started to wonder how could we not think
about the universe itself based on the laws that we’ve discovered not simulated. So, that the way that we actually simulate
the universe, it might actually give us hints that the universe itself could be a numerical
simulation. And then you would start thinking, well, let’s make
assumption that if that scenario is the case, and if that simulation is actually—has similarities
with what we do in our research and just drawing parallels between our algorithms
and techniques that we use to simulate laws of nature, and making assumption that they
are similar, then what can we actually conclude about the
universe as a simulation. Can we actually make predictions for the signatures
that we should go after and test? So, that’s that approach we took. And it
was a fun idea and fun paper became of it with my collaborators Martin Savage and Silas
Beane at the University of Washington. And that’s basically why I’m here. I’m
trying to—>>TYSON: So, the prospect of
this being true didn’t freak you out at all?>>DAVOUDI: No, I think it’s a fun idea.>>TYSON: Okay. Just it’s fun for you?>>DAVOUDI: Yes.>>TYSON: Okay. Fine. So, Max,
you’ve got a book on this, too, right? So, what’s going on with you?>>MAX TEGMARK: Yeah. Well, already as a kid
I was always very fascinated by these very big questions about what’s really going on with this reality.
I remember actually lying in this hammock I had put up between
two apple trees back in Stockholm, Sweden when I was 13, reading Isaac Asimov actually. I’m very honored to get to be here. It really makes you think about these big,
big questions. And the more I learned about later on as a physicist, the more struck I
was that when you get deep down under the hood
about how nature works, down to looking at all of you as just a bunch of quarks and electrons,
the rules—>>TYSON: And you, too. It’s not just us. Yeah. Looking at you as a quark, no, you would come
under this category as well.>>TEGMARK: Yes. I am a quark blob, too, I confess. But if you look at how these quarks move around,
the rules are entirely mathematical as far as we can tell. And that makes me wonder,
if I were a character in a computer game, who starting asking the same kind of big questions
about my game world, I would also discover eventually that the
rules seemed completely rigid and mathematical. I would just be discovering the computer program
in which it was written. So, that kind of begs the question: How can
I be sure that this mathematical reality isn’t actually some kind of game or simulation?>>TYSON: So, you’ve analogized
yourself to Super Mario in a—that’s who you are?>>TEGMARK: I don’t know if that’s
a good thing or a bad thing.>>TYSON: So, Jim, I just remembered
you started all of this a few years ago, in my mind at least, just triggering the idea that in your research
you found things that forced you to consider the likelihood that somebody programmed us.
Could you—>>JAMES GATES: Well, first of all, I would
disagree with you. I’m not sure somebody programmed us, but that’s—you and I had a conversation
where I pointed out that in my research I had found this very strange thing. Physicists,
I like to say we all belong to a company called Equations-R-Us because that’s how we make our living, is
by solving equations. And so I was just going through solving equations, and I was then
driven to things that Max knows about, these things called error-correcting codes.
Error-correcting codes are what make browsers work. So, why were they in the equations that
I was studying about quarks and leptons and supersymmetry? And that’s what brought me to this very
stark realization that I could no longer say that people like Max
were crazy.>>TEGMARK: Okay. [LAUGHTER]>>GATES: Or stated another way, if you
study physics long enough, you, too, can become crazy.>>TYSON: That’s a corollary to that idea. Yeah.>>GATES: And I’m also a science fiction
fan like Max, who talked about his encounter with Asimov. I was reading at age eight, as opposed to
13, sir.>>TEGMARK: I hang my head in shame.>>TYSON: Snap.>>TEGMARK: Got off to a slow start.>>GATES: I was reading at age eight
a science fiction book by an author named Paul French. And some people in the audience
might know that’s a pseudonym for Isaac Asimov.>>TYSON: Oh.>>GATES: So, science fiction drove me
into science in some sense. And then now in my 65th year of life, I find out I have to
make friends with Max and people like that.>>TYSON: So, Lisa, I kind of
brought you on the panel because I knew you—I mean, you’re a rationalist in all
this. And so I was expecting—I don’t know what to expect. I just needed to anchor this in somebody who
I knew was not going there. So, where—>>LISA RANDALL: Yeah. So, actually—well,
I can’t say I decided to be on the panel because I think I said what date is it, and
they were like, “Thank you for agreeing to be on the panel.” But I have to say I’m curious not so much
about the question of whether we’re a simulation because I think it’s only interesting insofar as there are ways to test it. And we can come back to that, I think, very
much in terms of how the laws of physics operate and whether we can actually distinguish that.
But I actually am very interested in why is so many people think it’s an interesting
question. Like why is the audience here? Why is this panel here? Because really to first approximation we can’t
really distinguish it. So, I think the interesting question is: Why
do we feel compelled to want this to be true, or even think this
could be true? And how do the laws of physics operate? And are there really ways that we
could eventually test whether there is something that distinguishes
just a true universe? But I have to just say if the inference is
simulation, I don’t understand why it gave me a cold today.>>TYSON: Okay.>>RANDALL: So, my voice might go. But
I also think sometimes some of the ridiculous things in the universe and think, really, why would that be part of the simulation?
And I realized that if I was doing a simulation, I would definitely put those things in. So,
there you go.>>TYSON: Okay. Well, thank you
for that. Now, we couldn’t have a panel without a philosopher. David, we needed some
philosophical—>>DAVID CHALMERS: I know how you love philosophers,
Neil. [LAUGHTER]>>TYSON: I’m on record for
some comments about philosophers that got him a little ticked off. Buy, anyhow. So, David, what do you—philosophers
have been at this for a while, yourself included. So, how do you see all of this happening or fitting in to the worldview?>>CHALMERS: Well, philosophers like
to ask the big questions about the world; the foundational questions.
And this is one of them. Actually, I blame Isaac Asimov for all this, at least in my
case. I got into thinking about these big questions
when I was a kid. I read just about everything that Asimov was writing. Not just the science
fiction, but the science fact, the history, the detective novels. I read multiple volumes of his autobiography. But throughout Asimov’s
work, this was a guy that was just interested in the big questions about the nature of reality
at all levels. And that, ultimately, drove me to think about questions about consciousness
and the mind, which I could approach as a philosopher because philosophy allows you to step back
and say what is the science here telling us. But this question about the simulation corresponds
to another of the great questions of philosophy, which is basically how do we know anything about the external world at all. And Rene Descartes said how do you know you’re not being fooled by an evil genius into having an impression of this world around
us? Even though none of it really exists. Well, the contemporary version of that question
is: How do you know you’re not in a simulation like The Matrix? In which case, allegedly, none of this really exist. And, to me, that
question is just extremely interesting because it seems nothing we could know could rule out the hypothesis
that we’re in a simulation. But you also want to think about what follows. Some people think if we’re in a simulation,
then none of this is real. I think if you adopt the kind of perspective which, say, Max was suggesting a second ago, where
the universe is all mathematical or informational, this allows us to reorient our attitude to this question and say, okay,
maybe we’re in a simulation. But if we are, all this is perfectly real because all the information is there in the
simulation. All the math is there. All the structure is
there in the simulation. So, I’d say, well, maybe we’re in a simulation.
Maybe we’re not. But if we are, hey, it’s not so bad.>>TYSON: If I do this, you feel
that.>>CHALMERS: Yeah.>>TYSON: Okay. So, that’s real. That was a real punch. Yeah. So, Zohreh, let me ask you, I see you coming
to this almost from the most pragmatic side. You’ve done experiments with your colleagues.
Or you’ve had hypotheses with your colleagues. Could you
just detail for me where you landed in one of those papers that you guys published?>>DAVOUDI: Sure. So, what we did is
not actually doing the experiment. We proposed that experiments could go and look for the signs of possible underlying
simulation for the universe. And the reason we thought about this, as I
said, 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 very
simple laws governing the interactions among these particles. However, when you think about all these complex
systems of atomic nuclei and larger systems in the
universe, the ordinary matter in our universe, it all emerges from those simple, fundamental building blocks and these
interactions. So, we’ve been trying to just input those
simple mathematical structure with a few degrees of freedom, these quarks and gluons, and then see how these, for example, atomic
nuclei emerge from these simulations.>>TYSON: So, you’re building
the universe from the ground up?>>DAVOUDI: Exactly. But what are the
limitations? We don’t have infinite computational resources. We have very large super computers in the national
labs, for example, that we can compute these interactions basically and build up these systems. However, we are still limited. And the reason
is that if you’re interested in simulating the universe, and you don’t know what the
size is— it could be finite or infinite. However, we
are limited to a finite size. On the other hand, if you think about even
a finite side, there are infinite numbers of points on these in this finite size that you have to simulate
to get the physics right. However, we are not capable of inputting infinite number of
information 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 simulations
to get the answer right.>>TYSON: Yeah, but just because
you can’t—we can’t do it because we’re limited, why should that mean the whole universe is
limited?>>DAVOUDI: So, wait. So, this is the
point.>>TYSON: I’ll wait. I got
time.>>DAVOUDI: All right. So, we can do
it, and then you—based on assumption that if
there is an underlying simulation for the that has this problem, that has the problem
of finite computational resources—just as that has this problem, that has the problem
of finite computational resources—just as
that has this problem, that has the problem
of finite computational resources—just as we do—then what happens? Then the laws of nature, the quantum mechanics
and whatever interactions have been going on, has to be put on a finite set of space-time points in
a finite volume, and then just a finite number of quantum mechanical paths to a process can
be evaluated. So, these are the assumptions. So, if the
simulator of the universe, in whatever form it is, is just finite computational resource
and not infinite, then it’s limited to simulate the universe
in 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 in
the observables we calculate, that could tell us that we started from a
non-continuum space-time. Then apply it to an underlying simulation
of the universe and make the same assumption, then what would you see? And that’s basically
what we look for, and list a few observables in our universe
that might lead to actually constrain this scenario under this assumption. And one of which is looking at the spectrum
of cosmic rays. Because what happens if these very high energy cosmic rays that approach
the earth, they are actually traveling in a discrete
space-time, as opposed to a continuum. Then their equations that basically special relativity that would
describe the relation between the energy and momentum of this particle is modified. And then you would ask what would that modification
mean in terms of the observation we make in our
observatories, 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 the
universe. And then you might think about other signatures and maybe taking this scenario
more seriously and think about external—>>TYSON: So, cosmic rays, it
would be your pathway to the limits of what has ever been measured.>>DAVOUDI: Exactly.>>TYSON: And then seeing at
that limit you’re probing the limits of the programmer of the universe.>>DAVOUDI: Right. Because these cosmic
rays 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.>>TYSON: They’re higher than
anything we produced in our particle accelerators.>>DAVOUDI: Exactly.>>TYSON: Yeah.>>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 way
of probing if the universe—if the underlying space-time is discretized or just a continuum.>>TYSON: So, Max, like I said,
you’ve written a book on this. Yet, you told me offline that you have an argument
that would argue that—>>TEGMARK: That maybe we’re not simulated
after all?>>TYSON: Yeah. Maybe we’re
not a simulation after all. So, where does that land?>>TEGMARK: Yeah. So, before giving a counter
argument, let me give the pro argument. Of course—>>TYSON: So, you can give arguments
in both directions here?>>TEGMARK: It’s fun to argue with yourself.>>TYSON: Okay.>>TEGMARK: Of course, we all—as David
mentioned—have seen the argument, the idea, of us being simulated in The Matrix
and in science fiction going even far beyond that. But the guy who really started foreseeing scientists to take this a bit more
seriously, and gave this idea a bit more scientific street cred, I think, is Nick Bostrom, my fellow Swede—Nick Bostrum—who
published this very dry academic article that’s pointing out that—>>TYSON: He’s a philosopher?>>TEGMARK: Indeed, indeed. And he pointed out that it seems like the
laws of physics allow us to build amazingly powerful computers way beyond what we have now; solar system-sized
things, which could simulate minds that would feel just like us. And then he went on to
say it seems overwhelmingly likely, if you don’t
wipe out here on earth, that in the future the vast majority of all computations and
all 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 the
pro argument. Now, it sounds good, but—>>TYSON: So, just to clarify,
so what you’re saying is if simulating universes becomes a pastime
among those who have access to high powerful— to highly powerful computers, and we are in
a universe, we’re probably in a simulated universe, even if one of those universes is
actually real.>>TEGMARK: Right. That’s basically—>>TYSON: Is that a fair—>>TEGMARK: That’s a fair summary, yeah.
And if you’re not sure at the end of the night whether you’re actually simulated
or not, my advice to you is go out there and live really interesting lives
and do unexpected things so the simulators don’t get bored and shut you down. [LAUGHTER]>>TYSON: Is that the cause of
death? Okay.>>TEGMARK: But now in terms of the counterargument,
if you just take Nick seriously—>>TYSON: That’s the cause of death.>>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 in
the simulated world we can build all these supercomputers in the future, and there’ll be all these simulated minds
and so on. And we can make the same argument all over again and convince ourselves that
actually we’re doubly simulated. And then we’re
a 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 be
all 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.>>TYSON: So, the turtles all
the way down.>>TEGMARK: Turtles all the way down. And
at this point, I get this sinking feeling that there’s something rotten at the core of this argument.>>TYSON: Okay.>>CHALMERS: The answer is we’re at level 42.>>TYSON: Good answer.>>GATES: No, no, 137.>>TYSON: One-thirty-seven. That’s
the fine structure constant.>>GATES: Of course.>>TEGMARK: And I think where the problem lies is that when you make this argument about
what kind of minds are really the most common, the most simulated and non-simulated, it assumes to answer that you have to know
what 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 here
in our simulation— if it is one—are. We need to know what the
real laws of physics are in the basement universe that’s the foundation. And, if so, we don’t
really have access to that. So, that’s the philosophical nitpick, which
seems to be swept under the rug here.>>TYSON: Jim, where—>>GATES: Where am I?>>TYSON: Yeah.>>GATES: Well, first of all, I have
a 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—>>TYSON: Claims, yeah.>>GATES: Right. “Extraordinary claims
require 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 these
error-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 extraordinarily
unlikely. And I have to tell you that one of the reasons
I 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, said
effectively— this is not exact words, but effectively he
said if the simulation hypothesis is valid, then we open the door to eternal life and resurrection and things
that formerly have been discussed in the realm of religion. And the reason is really quite
simply. Because if you think about a computer— if we are a simulation, then we’re like
programs in a computer, as long as I’m a computer that’s not damaged, I can always
rerun the program. So, if you really believe that we are in a simulation, and there’s
some structure that runs that simulation, unless something damages that structure, then
we can be repurposed. And so it starts to break down a very funny barrier between what people often think as the conflict
between science and the conflict between faith.>>TYSON: So, what you’re saying
is that if we are simulated, that means there’s a code that’s doing it, and that code was started at some point. And
in principle, it could just be rebooted, and then all of this would happen exactly the
way it happened before because it’s running the same computer program.
In principle.>>GATES: If one accepts the simulation
hypothesis as an accurate description of nature—>>DAVOUDI: I would say that’s a useless
exercise. What would be more interesting is to actually—>>TYSON: The word was useless,
Jim, in case you missed that. [LAUGHTER]>>TYSON: Okay, you heard that. Okay. Emphasis on useless exercise. Go, Zohreh.
Go.>>DAVOUDI: Trying to repeat what you’ve
already done with huge computation resources is useless. What is more interesting is to go and change the parameters of the
simulation—the input parameters. Just put the same laws of nature, and then just change
a little bit the value of the parameters—the very fundamental
parameters of our universe. And then let it run and see what happens. It’s actually
very interesting idea—>>TYSON: It’s a fun thing
to do, as a scientist.>>GATES: But in changing those parameters you might cancel out my existence, in which
case I don’t think that’s very useful. [LAUGHTER]>>TYSON: The universe without
Jim. So, Lisa, isn’t this some of the foundation— couldn’t we account for a multi-verse in
this 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.>>RANDALL: Okay. So, let’s slow dow a bit here. So, first of all, I actually want to address
some 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 are
only useful when they have a well-defined meaning. So, among all possible scenarios we can actually
say which one is more or less likely. When we run into infinities, when we run into— it stops making sense. I mean, I could say
really by probability I’m very likely to be Chinese because there’s a lot more Chinese than
Americans. But I’m clearly not Chinese. So, probabilities are tricky, and you have
to be careful what you mean when you’re saying them. Another thing is I actually find the egotism
of 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. [LAUGHTER]>>RANDALL: But in terms of feedback—in terms of error-correcting
code, I think it’s very likely that there were
going 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 cut
things off, those universes don’t survive. So, there
have 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.>>TYSON: Right. That assumes
that the programmer makes the same kind of programming—is susceptible to programming
errors and programming bugs that we are.>>RANDALL: It’s not even intentional.
It could be just that the computer itself is subject to error. I mean, it’s only firing
things somewhat random—I mean, ultimately, there’s uncertainty in everything. Nothing
is created perfectly.>>TYSON: Quantum uncertainty.>>GATES: Can I jump in here?>>TYSON: What?>>GATES: Because she’s raised—in
fact, I think an incredible point about this.>>RANDALL: As long as you come back to me afterwards.>>JAMES GATES: May I take up your time? I’ll cede minutes back later.>>TYSON: Yes, okay.>>GATES: This point about error correction
is something that when people have—general public has looked
at my work, they say, “Oh, you must believe in simulations.” And I’ve said, no, actually
I don’t. And the reason is because precisely the point
the Lisa points out. If you look in all of nature and ask are there
any other places in nature—not in engineering, not in computers, not in the things that we
build, but in nature herself, is there a discussion
in science about error-correcting codes? It turns out there’s one place and one place
only that I have been able to identify. That’s in evolution and genetics. And there’s been
a discussion—>>RANDALL: Or any biological system.>>GATES: Right. Or any biological—right. And it’s not that we think life is some
kind of programmed simulation. It’s because the universe itself, as Lisa had said, has to have feedback mechanisms
that basically sustain a structure that propagates faithfully forward in time. And I think that’s
in fact the most critical point. And you have your time now.>>LISA RANDALL: Thank you. And anyone who
wants to take my time to agree with me— [LAUGHTER AND CROSSTALK]>>RANDALL: But as far as the multi-verse
theory goes, so we have to be careful by what we mean by
that. I mean, at some underlying level we still think it’s physics in action. Now, what might change
in different universes, we might actually have different forces. We might actually have
different strengths of interactions; the kind of thing that gets simulated. I mean,
we simulate strong interactions the way that were described.>>TYSON: Just to be clear, strong
interactions are the forces that bind atomic nuclei.>>RANDALL: So, protons.>>TYSON: Yeah, protons that
are the same charge that are sitting right next to one another
in 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 force
down there holding it together. And there is a really strong force. It’s called the
strong force. Okay, so go on.>>RANDALL: Which is strong.>>TYSON: Yeah. Okay. Just to be clear.>>RANDALL: So, and there can be different
possibilities for what these parameters can be. It’s still underlying you still believe
that there’s the laws of physics that are operating. So, the question—I mean, so it’s not a
simulation. It’s just— I mean, it’s in principle possible that
there are universes we don’t communicate with that are so far away we’ll never send a
signal, they’ll never send a signal. So, for all intents and purposes, there just are different universes. That doesn’t mean they’re
simulated. It just means they’re different from ours and they can have different properties. To really distinguish a simulation, you really
do have to see just our whole notion of the laws of physics
breaking down, or some of the fundamental underlying properties. So, it would be extremely
interesting to look for the kind of violations of Lorenz invariants that
were discussed earlier, or things like quantum entanglement no longer hold it. Not because
of interaction of the environment, but just the computer just couldn’t keep track of
stuff. 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 simulations
are 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 approximation
s are valid.>>TYSON: But, David, what do
your philosophical circles say about proposing an experiment that might falsify these ideas?>>CHALMERS: Look, I don’t think you’re
going to get conclusive experimental proof that we’re—we’re certainly not going
to get conclusive experimental proof that you’re not in a simulation. I suppose we
could get some kind of various—>>TYSON: Well, why not? You
just declared something. Why can’t a clever person come along and—>>CHALMERS: Because any evidence that
we could ever get could be simulated. That’s basically the reason. Sorry. Maybe—>>TYSON: So, if I find evidence
that we’re not simulated, the great simulator—>>CHALMERS: They could have just planted
that for you.>>TYSON: —put that in.>>CHALMERS: Yeah. They’re one step
ahead. However—>>TYSON: We’re done. We’re
done here.>>CHALMERS: Maybe we—we probably could
get pretty strong evidence that we are simulated. If someone wrote up
in 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—>>TYSON: Except it would be
in Chinese to get the most number of people to read it.>>CHALMERS: Then we’d probably have
a pretty good reason to think we’re in a simulation. Either that or the
weirdest non-simulated universe that anyone ever imagined. So, for a philosopher anyway, it’s not fundamentally a matter of experimental
proof. 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 in
a simulation. There’s a hypothesis that the universe is computational. Those are closely related. If we’re in a
simulation, the universe is fundamentally computational. But it’s not true that this
universe is fundamentally computational we’re necessarily in a simulation. Because the simulation hypothesis is a combination
of two things.>>TYSON: That’s an official
thing, the simulation hypothesis.>>CHALMERS: Yeah. The simulation hypothesis
says 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 created
it. And around here is where you might be able to get a little theological and say, okay, well, it’s a
naturalistic version of the god hypothesis. But, anyway, my worry about Zohreh’s stuff, which is really cool, it’s really evidence
for the much weaker hypothesis that the universe is some form of discrete computation and is
completely neutral on the question of whether this is actually
a simulation in the sense of something that was created—>>TYSON: With intent.>>CHALMERS: —by a simulator.>>TYSON: So, Max, do you mind
if I call you Mario from now on? Because if you’re Mario in the computer game—>>TEGMARK: Starts with M-A, so you get the two letters, yeah.>>TYSON: I imagine Mario—someone
coming into a Mario game and calculating how high he jumps and how
fast 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 understanding
of what’s outside the game?>>TEGMARK: Yeah, that’s a really deep
and good question. Mario might—if Mario can ever—even if he figures out exactly
the rules of his world—>>TYSON: Then he just figures
out the rules.>>TEGMARK: —he won’t even know if
he’s running on a Mac or a Windows box or a Linux box because all he has access to is this higher
level of this sort of emergent reality. And we might, at some level, be stuck in that situation in physics also. It’s
quite fascinating to think that so much of what we’ve figured out, for example, about
how a glass of water works with waves and vortexes and things, we figured
out already without having a clue about the substrate. We didn’t even know there were
atoms. But the same kind of questions that you’re asking, which I think are awesome, the kind of questions
where you ask suppose this is actually somehow simulated, suppose the simulators cutting corners, how
would that show up? Actually, it has been incredibly useful in
the past. If you imagine going back 200 years and trying to simulate this water as an infinitely— a continuous liquid where there’s a pressure
and a density that has to be defined with infinitely many decimal places and
infinite points, that sounds horrible to simulate. So, maybe
whoever did this cut corners. Maybe there’s a smallest kind of chunk of object—let’s
call it atom or something— you can figure out then what are the departures
from this simplified continuous physics that I’m guilty of teaching my undergrads at
MIT about this morning? And you would figure out a way there’s this
one little thing, which is different.>>TYSON: He trained down a few
hours ago from Cambridge.>>TEGMARK: Yeah.>>TYSON: Thank you for coming
and for—>>TEGMARK: Brownian motion that things
should jiggle around in a weird way. And Einstein found that, got the Nobel Prize for it importantly. And
I think that the sort of thing you’re doing is awesome. Look for corner-cutting evidence. I suspect
that whether we’re simulated or not there are a lot of things that are wrong about what
we assume today. I am very skeptical that we really have a
continuous space that can be stretched infinitely many times. It seems like some sort of simplification
that we came up because it was easier to do the math.>>DAVOUDI: But do you ever ask why
should that be the case? Why do we need a discretized universe? I mean, if you put away the simulation hypothesis
or a computational hypothesis, why should we even think about a discretized
universe? Why not continuum? It’s [unintelligible].>>TYSON: So, this is an important—>>TEGMARK: Yeah.>>TYSON: I don’t want to call
it a problem in physics, but a reality of physics that our macroscopic world looks continuous
to us. And that has a certain simplicity of modeling. And then as you get smaller and
smaller and smaller, it’s no longer continuous and it’s discrete, which may be easier to
calculate than being able to be divisible all the way down to an infinitesimally small
bit. Because now you need that much bigger computer
to do it. By the way, we have—>>RANDALL: So, you know something that
none of us actually know. This is actually a real question, whether
space is discrete at really small scale.>>TYSON: Well, we run into this
problem when we do flyovers in the Hayden Planetarium. We have a data set for a planetary
surface— let’s say Mars—and you had a given distance.
And from that distance you can see Olympus Mons, the biggest mountain around, and Valles
Marineris, and you say, fine, now I want to get closer. Well, to get closer, and have more information
come 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 reach
a 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’t
have the data. We’re not there. It doesn’t exist for us.>>CHALMERS: So, anyone’s who’s used
one of these virtual reality devices, like the Oculus Rift, knows there’s something
called the screen door effect. It’s like you can—if you look closely
enough you can see the pixels, so it’s not a perfect simulation. So, I guess really what
Zohreh is doing is saying, well, we can get empirical evidence for a screen door effect
in real physics.>>DAVOUDI: Yeah, I think it’s actually
a 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 bothered
Feynman a lot that why do you need infinite numbers of degrees
of 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 without
actually needing that infinite amount of information.>>TYSON: What I meant to add
is 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 need
that much bigger disk space to have it ready and loaded to
be able to go from the bird’s eye view down to any kind of small— I mean, we rapidly run out of capacity to
calculate.>>TEGMARK: And that’s a great controversy
that even mathematicians have been really arguing passionately about for over 100 years. Gauss, one of the greatest mathematicians
ever, 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 kind
of hubristic to say that you need an infinite amount of
information to figure out the height of my wine glass or anything. Nature seems perfectly
about to figure out what’s—>>TYSON: There’s water in
that glass, by the way.>>TEGMARK: Yeah, what to do. And we have
this toy model that you need an infinite amount of information to do things. I think you’re on to something very deep there, Zoreh, and that nature actually—infinity is just something we made up for convenience. And as we dig deeper, we’re going to find
that maybe even space and time itself is at some level digital.>>RANDALL: So, can I just say something
by way of clarification? Which is just in physics we don’t actually prove any theory. We can
rule 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 most
fundamental has some underlying structure. And so that’s why all the physics we’ve
done works. That’s why we really don’t need to have an infinite amount of information
at any time because we don’t have access to an infinite
amount of information. And we can’t even ask the question or tell whether or not there’s
this underlying infinite amount of information. So, it’s not just we can’t just ask the
question whether the universe is a simulation. We can’t ask if any physical theory is absolutely
correct. We’ll never know the answer to that. All we can know is that we’ve tested it
up to a certain level, at a certain level of precision, over a certain range. And so these questions all come with it, and that’s why I can describe this glass of water without knowing about atoms, because I didn’t have—wasn’t doing an
experiment where the effects of the atoms became manifest. And the same might be true
of the universe as a whole. So, we can have in the back of our mind there
may or may not be an infinite number of degrees of freedom. But that’s not what we’re
actually testing.>>TEGMARK: Let’s disagree on one thing,
though. I think there’s one fantastic example where
we can tell it makes a huge difference. I think the biggest embarrassment we have arguably in fundamental physics and cosmology
right 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 the
size forever. So, I think you should question that.>>RANDALL: Well, it doesn’t have to
be infinite. It could just be a large number. It could be 10 to the 500. I mean, it doesn’t
really matter if we say it’s infinite. Why don’t we just say it’s a lot?>>TEGMARK: But you can calculate probabilities
as long as it never gets infinite. It’s exactly infinity that kind of, arrrgh, gets us.>>TYSON: So, he’s cool with
10 to the 500, is what he’s saying, which seems like a really big number.>>RANDALL: I know.>>TYSON: That like equals infinity
to me, I think.>>RANDALL: But that’s exactly the point.
That’s exactly the point.>>TYSON: Jim, is there any functional
difference at all between admitting that we live in a computer
simulation and saying that’s basically a secular god? What’s the difference?>>GATES: Well, first of all, I’ve
decided my name should be Morpheus, not Jim.>>TYSON: Okay. Well, let me—>>TEGMARK: I’m Mario. Nice to meet you,
Morpheus.>>TYSON: Morpheus.>>GATES: Exactly.>>TYSON: Yes. You have to see
the movie The Matrix and play video games to follow this conversation at this moment.
Morpheus.>>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 accurate
view of our universe is equivalent, I believe, to the notion of
a 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 secular
definition. 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 these
are Einstein’s words—drums into us that contemplation alone, without observation of
nature, is totally useless in trying to come up with
an accurate view of nature. So, it’s that ability of us—our human ability to observe
the universe that actually defines science. So, if you
can’t give me something that I can observe, I don’t know how to do science.>>TYSON: Okay. So, what you’re
saying is that if in fact there is a programmer who
would be philosophically equivalent to a Creator, and you can’t observe them, they’re just outside the realm of science.>>GATES: I think that’s the definition.>>TYSON: David, do you have
to be defined by that?>>CHALMERS: Well, I think there’s
a theological reading, if you like, to the simulation hypothesis. It says all this was
created, but what’s interesting is at the same time
it can be seen as a kind of a naturalistic theology. A naturalistic hypothesis—from
the point of view—>>TYSON: Is that the first time
the phrase has ever been uttered? A naturalistic theology.>>CHALMERS: I think it’s out there
already.>>TYSON: Oh, it’s out there.
Okay. All right.>>CHALMERS: Simulation theology, you heard it here first. Simulation theology is the coolest kind of
naturalistic theology, from the point of view of the—>>TYSON: Actually, there’s
a book in 1750—or who was it?>>CHALMERS: Yeah, David Hume was into
naturalism.>>TYSON: No, there was—who
was the fellow who wrote the book Natural Theology? There was a book with that very title.>>CHALMERS: Yeah.>>TYSON: But not natural simulation
or simulated theology.>>CHALMERS: If you think about is from
the point of view of the simulated— I mean, we in this universe can create simulated
worlds, and there’s nothing remotely spooky about that. People are already doing it with
virtual reality and the Sims and Second Life. And whatever this is is just a far more sophisticated
version of that. So, we just need to move that picture to the
next universe up and say, hey, maybe that’s what’s happening to
us. So, we got a creator, but our creator isn’t especially spooky. It’s just some teenage hacker in the next
universe up whose mom’s calling him in to dinner.>>TYSON: Working in the basement,
yeah.>>CHALMERS: So, I think you could be
led to at least entertain this idea by perfectly naturalistic ideas as, say, Nick
Bostrum was and say, okay, maybe this is the kind of theology which even
someone who’s got no sympathy for spooks and gods and ghosts, needs to object to.>>TYSON: So, that’s an interesting
point because we don’t think of ourselves as deities
when we program Mario, even though we have all power over how high Mario jumps. Because that’s a line in the code. So, you’re
right. You just take it up a few notches. There’s no reason to presume
they’re all powerful other than just they fully control everything we do, say and think.>>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 Sim
Life or something. He’d make a whole town. He’d build up the buildings, and you got the trees and the jungles and
the creatures. And then he’d say now comes the good part, and he’s send down fires and floods and
such. I was like, finally, I understand the God of the Old Testament.>>TYSON: Because it is true
in our world we have fires and floods. I played one of those Sims—Sim City because
I’m a city kid. And—the early, early low-res simulation. And there’s a feature, you build up the—you need money. You’re
mayor of a city, and you construct buildings and you need the schools and the fire departments. And then every now and then Godzilla stomps
through your city and you say that’s not real. I’m trying
to be real. But then it’s kind of real in the sense that some major disaster can— you will confront like Hurricane Sandy or
9/11. Now, you’ve got to redistribute resources. So, I look at our real world, and these things
actually do happen. So, are they just trying to mess with us? Is that—>>CHALMERS: The way I think about—I
mean, who knows if there’s actually a simulator who’s actually doing any of this. But if
you do take the simulation hypothesis seriously, it’s got a couple of elements of a traditional
god. This person could be all knowing about our universe, could be all powerful. The one
thing 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 not established yourself as being
worthy of worship. I refuse to—>>NEIL DEGRASSE TYSON: Right. Because they’re
all powerful and all knowing, but not all good.>>CHALMERS: There’s no reason to think
they’re all good.>>TEGMARK: Cut him some slack. He’s
only five years old. [LAUGHTER AND CROSSTALK]>>CHALMERS: You’re going to be maturing
one of these days.>>TYSON: Zohreh?>>DAVOUDI: Yeah. So, I think there
is a big danger in trying to compare our idea of simulation with what comes with
computer games, whether you’re talking—at least in my point of view and I think a physicist’s
point of view. What’s called the simulation is you just
input the laws of physics, and nature and universe emerges. You don’t
actually try to make it look like it’s something going on. You don’t try to— the same as with computer games. You don’t
interfere with what you’ve created. You just input something that is very fundamental and just let it go, just as our universe.>>TEGMARK: Like deism.>>DAVOUDI: Yeah.>>TYSON: In other words, you
set the laws into motion and let the universe unfold.>>DAVOUDI: Exactly.>>TYSON: However those laws
prescribe.>>DAVOUDI: Because a priority—you
don’t know what happens because the universe is complex. The laws of physics are simple, but you don’t know what kind of complexities
you should expect. And then you just get it wrong
and things emerge, and we just watch.>>TYSON: But, Lisa, in the search
for 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 Everything
panels here— you’re going to find out the one equation
that the five-year-old working in the garage wrote down that made our entire universe.>>RANDALL: Well, you might recall, since
I’ve done this a couple times, that the Theory of Everything, I think, is very badly named for a lot of
these reasons. Because even with the equations, as was pointed out earlier, you could start your system in very different
ways. You can have different conditions. And there’s a lot that we don’t understand. I mean, even if I understood quantum gravity
at a fundamental level and could derive all the equations, that’s still not going to help me predict
waves at a practical level. I mean, the computer simulation will never be that detailed, in my opinion. It’s much better to go to
different levels and figure out what’s going on at what I would call an effective theory
approach. So, even with the fundamental equations— now, I mean, clearly if you had infinite computing
power, 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 mean
it’s fundamentally how it’s working.>>TYSON: But, Zohreh, you started
this whole discussion by describing—trying to obtain an understanding
of the basic forces of nature and the particles and build up from there. But isn’t there surely a gap between what
you know drives the behavior of individual particles and what might be emergent features in a macroscopic
system. 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 macroscopic
gas laws by knowing every single particle at every single instant. I don’t know that they’re fully reducible
to 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?>>DAVOUDI: I do admit to that, and
it is in fact—>>TYSON: Okay, good. Thank you.
You admit to it. No, go ahead.>>DAVOUDI: No, this is indeed a field
of research now, for example, in nuclear physics we know that these microscopic features about
particles and building blocks of that would contribute
in strong interactions, but we don’t know exactly how to get these
complex system of nuclei. And we have very good microscopy and phenomenological models that describe all these larger-scale phenomena, but we still don’t know how to get them
from this phenomena. So, that’s what, as physicists have to—>>RANDALL: In principle, if you could
do it—I mean, if you had infinite computing power.>>DAVOUDI: Yeah.>>RANDALL: In principle, you could actually
see a system that exhibited the gas laws. The question is whether we as scientists would
call them—deriving the gas laws. It wouldn’t be a very useful description. It would mean that we’d have to have these
enormous computations every time to do it, rather than solve an equation that, as you
know [unintelligible]—>>TYSON: Oh, so I never heard
that before. You’re assuming that if in fact we could
compute the behavior of every single particle in a gas, that out of that would emerge the macroscopic
gas laws.>>RANDALL: Well, it would behave according
to the gas laws. That doesn’t mean that you would know what those gas laws are.>>TYSON: Okay. That’s confident.
So, what you’re saying is it’s not emergent Because I’m intrigued which of you mentioned
the water—>>RANDALL: No, emergent means that it
emerges from the fundamental laws.>>TYSON: But because we understood,
to a very high degree, a fluid dynamics long before we knew that fluids were made
of atoms.>>RANDALL: Right.>>TYSON: And I don’t know
how much the public knows that atoms are—though, the idea is old, evidence that atoms are real is relatively
recent. And even as recently as the year 1900, it
was still kind of not sure. And it wasn’t really until Einstein and
Brownian 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.>>RANDALL: Right. But we also now can
derive fluid dynamics from the atomic description, in certain cases. Not all fluid dynamics, but some of the properties
of condensed matter physics we can derive by that.>>TYSON: Okay, I’m glad to
hear that. So, we’re still talking about reducible things.>>TEGMARK: They’re two separate things,
though. We mustn’t conflate. On one hand, I think in principle it can derive
all these higher level things, I think, even ultimately even consciousness
like David Chalmers is working on, from starting out with a quark since that—>>TYSON: You’re going to bring
consciousness into this?>>TEGMARK: In practice, on the other
hand, whether we humans are smart enough to figure it out— that’s a whole different story. And I think
that’s— I’m guessing that’s what you were getting
at there. You weren’t saying that there’s some mysterious epistemological gap
that we can’t—>>DAVOUDI: Oh, no, no. That’s not
what I meant.>>TEGMARK: But that we might be able to
understand.>>DAVOUDI: We haven’t yet have the
resources and probably enough tools and understanding to fill that gap. But the phenomenal equations are there. It’s
just a matter of when we actually get there.>>TYSON: So, I’m curious—this
brings me to a point that we did not discuss earlier in the notes that we shared. You can know everything you can about cell
biology, about how life works. And it’s not obvious to me that by just
studying 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 actually
programmed it in to do that. That’s just something that resulted.>>RANDALL: Right. So, the way I would
describe it is I would say that the fundamental— whatever’s fundamentally there—that substrate—is
essential to whatever happened, but is not necessarily essential to your description
of what happened. And so the laws are following from this, but
it’s not giving an explanation. So, I can note that there’s atoms, but it
doesn’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 description
of 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] measure it.>>TYSON: David, you and your
consciousness cronies, is it generally recognized that consciousness
is an emergent phenomenon of a complex brain?>>CHALMERS: Yeah. Well, this word emergence
is kind of word that people used to cover a huge variety of sins. I mean, sometimes I think it’s kind of a
magic 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’s
the kind you get with, say, complex systems like the Game of Life; Conway’s Game of Life where the cells blip
on and off, and you get complex phenomena like gliders
that move along. You know it’s surprising, and you wouldn’t
have expected it, but you can put together the equation that it’s totally predictable. You run the game of life over and again with
simple computational rules, it’ll be predictable again and again. Evolution is interesting at the immediate
case. Maybe given the laws of physics in certain initial conditions. You can run them again and again. I don’t
know. Maybe you’ll get—maybe it’ll turn out
evolution arises 60 percent of the time. If so, that’s incredibly cool, and then
that ought to be explainable in principle. Now, for consciousness, people sometimes say
consciousness is emergent, but there’s a gap there of a kind that we
haven’t even begun to close in the gap of consciousness. People can tell stories about life. People
can tell stories about evolution. No one’s even begun to tell a story that
enables you to predict the existence of consciousness from any number— any amount of underlying physical dynamics. It explains the behavior. It explains how
we walk, how we talk, but why that should actually feel like something from the first-person
point 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 to
explain.>>TYSON: Max, is there any role
of chaos theory in this? Because we know that in principle and in practice
there’s some systems that are so complex, that you cannot accurately predict its future
behavior. Now, is that true even if you had an infinitely
powerful computer?>>TEGMARK: No matter how powerful a computer
we build on earth, we can certainly not predict—we could not
have predicted that the Red Sox were going to win the World Series right after I moved
to Boston.>>TYSON: Okay.>>TEGMARK: Because precisely of chaos
theory, where tiny changes in the position of some particle made
a huge difference later on. But—>>TYSON: Just the Butterfly
Effect.>>TEGMARK: Yeah. If things—>>TYSON: I’ve got to tell
you real quick, there’s the Journal of Irreproducible Results, which is if you’re a scientist and you come
up with something that you know isn’t right, but it’s a really cool calculation, you
publish 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 of
a 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 that
the cat falls, and then hovers over the— so, it’s stupid fun calculations. One of
them was— sorry for this interlude, but one of them
was there was some major storm system that happened that hit the East Coast of the United States, and someone
said, “We found the butterfly that caused this.” And they killed it and it was on display.
So, go on. So, this Butterfly Effect—>>TEGMARK: Yeah, yeah. I was just- apropos of complicated emergent phenomenon related to chaos and such, I just wanted to come back to what David was
saying about consciousness here, and kind of connect it with what you opened
with here. How can we test with scientific methods these ideas of whether we’re simulated or
not? Or at least update our odds in one way or the other. I think one thing that’s great
to do is what you’re doing. Again, looking for this evidence
of a simulator cutting corners to make the simulation easier to run. I think another thing we should do is if you
want to test this computation— hypothesis that everything is a computation,
or that everything’s mathematical, we should look precisely at the things where
we’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 bring
also that in under the type of things that we can describe with math. If we fail spectacularly on that, and can
realize 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.>>CHALMERS: Yeah. And there are people
who are pursuing the idea. As you know, the consciousness is fundamentally
about information processing in the right way when information, for example, is integrated
in 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 the
simulation hypothesis because it’s very natural to suppose that
in 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 there
could be a simulation of the whole universe. But if it didn’t have that biology, then no consciousness. It would just be a
world of—>>TYSON: A world.>>CHALMERS: —unfeeling zombies.>>RANDALL: I have a question, though.>>CHALMERS: Unfeeling physical dynamic.
So, it really makes a difference.>>RANDALL: How do you ever show that
something can’t be described mathematically? You’d have to believe you understood fundamentally
what the degrees of freedom are. So, you might just have the wrong description.
I mean, even in physics, I mean, we know classic examples
where 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 physicists
of 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 going
to be able to show that something has no mathematical description.>>TYSON: But, Max, you’re
big on the mathematical concept here. What you’re saying is everything is mathematics. And if everything
is mathematics, then everything is programmable.>>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. In
physics, we aren’t ever able to really prove that something is true. The only people who prove stuff are mathematicians. But if David and Giulio Tononi and Christof Koch and
others succeed in this endeavor to try to actually explain consciousness mathematically, it wouldn’t prove that things are purely
mathematical, but it would certainly be yet the great boost.>>RANDALL: I asked the other question
of how you [unintelligible].>>TEGMARK: Because if you just go back—let’s
go back to Galileo again. We were eulogizing him earlier, right, for
his great insights. When he wrote that our universe is a grand book written in the language
of mathematics, that was 400 years ago because he was so impressed
that things moved in parabolas and things like that. He had no clue why oranges were orange and
hazelnuts were hard and some things were soft. That seemed like it was beyond what he could
do with math. Then we got Maxwell’s equations, the Schrodinger’s equation, the standard
model 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 are
the things left.>>TYSON: I’ll invite him next
time.>>TEGMARK: Awesome. Well,
you can reincarnate him and bring him on.>>GATES: Just simulate him.>>TYSON: We’ll just have to
simulate him. That’s what we’ll do.>>TEGMARK: So, it’s really cool to look,
well, what’s left. Like consciousness, for example, and see if we can also make some progress
there. There’s no better way to fail on anything, including consciousness understanding than to tell ourselves, oh, we know it’s
impossible because of some principles, and let’s not try.>>TYSON: Yeah, those aren’t
good scientists who behave that way.>>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 description
of everything. Even consciousness, obviously, give many mathematical descriptions
of 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 Tononi is doing. But can you give an exhaustive mathematical description of it once you’ve given a full mathematical specification
of consciousness, have you understood everything about it, or is there some further nature
like the redness of the red, or the blueness of the blue?>>TYSON: What Max is saying
is that previous frontiers in that question were ultimately breached when enough smart
people came along to figure it out. So, whatever’s our state
of mind today, it would be unwise to suggest that it somehow transcends any access that
the future of math might—>>RANDALL: I mean, on some level we don’t
have an exhaustive description of anything because we understand that there can always
be something more fundamental, something we haven’t seen yet.>>GATES: I agree.>>TYSON: In fact, the very word
atom in Greek means indivisible.>>CHALMERS: Yes.>>TYSON: So, yeah, with that—how
long did that last?>>RANDALL: And unchanging.>>TYSON: Yeah.>>GATES: While we have been all bowing
at the altar of mathematics, [LAUGHTER]>>GATES: a number of us are aware of this result by
Gödel called the incompleteness theorem. And it even says in some sense mathematics
is incomplete. There are things in mathematics that you cannot prove. That’s what the theorems say. And so we,
as humans, I think—>>TYSON: In fact, Gödel proved
it.>>GATES: Yes. Yeah, right. He proved
it. That’s exactly right.>>TYSON: Gödel proved that
math cannot be proven.>>GATES: That’s right.>>TYSON: Yeah.>>CHALMERS: If it’s consistent.>>GATES: Right. If it’s consistent. [CROSSTALK]>>TEGMARK: In defense of our universe
here—>>TYSON: Somebody’s got to
defend our universe, so go ahead.>>TEGMARK: Standing up for our universe.
There’s actually no evidence that our universe is inconsistent, or that mathematics is inconsistent. Gödel
said that we humans, we cannot prove ever that mathematics is consistent.>>TYSON: Right.>>TEGMARK: We cannot prove that—that’s
impossible to prove that one equals two. But I think that’s probably more of a reflection
of our own limit—of the limitations that thinking beings have, rather than our universe has some kind of
identity crisis. Our universe seems to know exactly what it’s doing. It doesn’t seem very inconsistent except
when I watch the Presidential Debates.>>TYSON: Okay.>>GATES: Oh, boy, I’m not going there.
But, Max, that was precisely my point, that maybe what we’re talking about is in
fact part of our limitations. Not limitations on the universe, but—in science it’s very funny because
the way we do science— well, when I give public talks, I like to
say if you look at family in their house, you might be an anthropologist and record
what they do, and they turn the appliances off and on. And
you 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 maybe
you have a timer that does other things. And so the house has a set of rules for operating
when 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 could
take 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.>>TYSON: So, we’re all stupid,
is what you’re saying. [LAUGHTER]>>GATES: Actually, the universe made
us very clever, at least most of us. [LAUGHTER]>>TYSON: So, Jim, I got to ask
you something. Your discoveries of the checks—error-correcting
code 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 way
at some level. Could it be that how the saying goes, if you’re
a 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’re
finding IT solutions to your problems, maybe it’s just the fad of the moment. And you’re forcing a solution that is either
not real, or there’s a better one awaiting in a revolution that has yet to occur.>>GATES: Sure. So, the last time I was
here I actually misspoke. I used the name of Shannon when I meant Hamming
code instead. So, first, let me correct that for this wonderful
audience and mention it—>>TEGMARK: Error correction in action.>>GATES: That’s right.>>TYSON: Error correction—>>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 that
Lisa knows a lot about in Geneva because she has written papers about possible outcomes
in these observations.>>TYSON: Lisa, are you flying
to Geneva tomorrow?>>RANDALL: I am, but not for that.>>TYSON: Not for that, okay.>>GATES: So, the Large Hadron Collider
is going to explore more of the structure of the universe. So, first, the mathematics that I have done
will only become physics, or relevant to nature, when the LHC or some other observational device
says the idea of supersymmetry is correct. Then it will kick in. So, that’s a big if. There are lots of physicists
who don’t believe the universe will be supersymmetric. In which case, all I’ve done is an interesting
mathematical fairytale.>>TYSON: So, supersymmetric
proposes a whole other regime of particles that are counterparts to the particles that
we’ve come to know and love?>>GATES: Correct.>>TYSON: Okay. And they’re
yet to be discovered, but they could be describing a whole other parallel reality, awaiting our discovery?>>GATES: Well—>>RANDALL: But even that—I mean, I
just want to clarify. We may or may not find evidence at the Large
Hadron Collider, which is what’s being discussed. But that doesn’t even mean that supersymmetry
doesn’t exist. It means that we can’t find the evidence at the scales that we can
probe.>>GATES: Exactly.>>RANDALL: So, it could be that there
is some fundamental symmetry, and it’s broken at such a high scale that
we 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 measure
what we can. And then we have to allow for the possibility that we just haven’t had
the accuracy. We haven’t had the cleverness, or we haven’t
had the resources—>>GATES: Technology.>>RANDALL: —to be able to test certain
ideas. And so I think that’s right, that it’s
a combination of what’s out there and what we can actually do.>>TYSON: So, I don’t who among
you to ask this direction, so I’ll just put it out there in front of you like a piece
of raw meat, and you can chase after it, if you—>>RANDALL: You think we’re dogs?>>TYSON: Or you vegetarian—some
raw carrots. Okay. So, you can chase after it. I don’t know if any of you are vegetarian.>>RANDALL: Can you cook the meat at least?>>TYSON: I’ll cook the—okay.
We’ll cook the meat. My question is I remember physics 101 and
102 and 201 and 202, and as you learn the laws of physics, every
now 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’s
an asymmetry in there. There’s like you can have particles that
have electric fields like electrons, but you don’t have isolated particles that
are their own magnetic fields. There’s always a plus and a minus stuck together. So, they’re not symmetric that way in the
equations. And it’s like you cringe when you see that because part of us wants some
beauty and symmetry to the universe if it is—I don’t know. We’re holding
it 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 become
a 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 million
stuff that’s left over. Something broke in the early universe. And I ask you why aren’t these bugs in the
program that we’re dealing with?>>RANDALL: So, I’m going to actually
answer that.>>TYSON: You’ve got an answer
for that? Very cool. Very cool.>>RANDALL: So, it’s definitely not
a 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, you
have electrically charged particles. There’s an alternative description where
the fundamental particles would be magnetic. That’s not the universe we find ourselves
in. 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 have
some underlying symmetry that gets broken at some point.>>TYSON: So, who’s breaking
it?>>RANDALL: Who’s breaking—the universe.
The universe is [unintelligible]—>>TYSON: No, that’s not the
answer. [LAUGHTER]>>TYSON: I’m looking for a little more insight into
who’s breaking the laws of the universe than just the universe.>>RANDALL: Well, here’s a simple example,
okay.>>TYSON: Well, just to be clear,
we come up with what we saw are laws, and then if we see an exception we say that
there’s a case where the law is broken.>>GATES: No, no.>>RANDALL: Okay. Let me give you a simple
example.>>TYSON: And we’re okay with
that.>>GATES: It’s the symmetries that
are broken.>>RANDALL: Suppose I have a pencil—>>TYSON: Oh, sorry. Symmetries
that are broken.>>RANDALL: So, say I have a pencil standing
on end. I have rotational symmetry, right? We’d like to believe everything’s rotationally
symmetric. Why should one direction be different? So, I have a pencil standing on end. It’s
going 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 universe
that are like that. The fundamental laws are symmetric, but the actual universe we live in has broken.>>TYSON: So, we can’t look
for weirdness because if it is a program that’s running, which came up earlier, and we’ve all had
programs that crashed, what happens if our program crashes? Do we all disappear like
instantly? What are the consequences to this being a
program if someone unplugs it, if there’s a bug that crashes the entire system? Is there any piece of the universe where that
part of the program failed?>>CHALMERS: I have it on good authority
[unintelligible]—>>TEGMARK: A big spinning wheel here on
the stage going round and round and round.>>CHALMERS: I have it on good authority
it’s crashed five times during this panel discussion, but, fortunately, it rebooted perfectly and
we have no memories of it. That’s just good error correction.>>GATES: No, no, but, Neil, the point
you raised, in fact, is for me one of the most uncomfortable ideas about the simulation
hypothesis. That it’s running on some device, and that
the errors would then—how would it manifest itself? Well, in the way that I think most of us think
about it, it’s kind of the end of the universe. And, for me, the universe that I have studied
for 50 or 60 years is a kind of a—it’s a place of mystery, but it’s not a place of the fundamental
kind 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 pioneered
largely 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 is
if you don’t break the symmetries you don’t get us. You don’t get a universe with creatures
like us in it unless you break these symmetries. And so maybe the question we should—>>RANDALL: [Unintelligible 80:46] why
did I break those symmetries?>>GATES: That’s right. The simulation’s
like why am I breaking those symmetries? So, the fact of our existence says something
very deep about the mystery of this place we call the universe because the laws—the
symmetric laws, they’re beautiful. We write them with simple
equations on one or two lines. But if those laws held exactly, we’re not
here.>>TYSON: In fact, it’s just
a universe of photons.>>TEGMARK: I think that’s a very good
point you bring up there. At first, it looks like if someone’s simulated
this, they have been drinking too much or whatever, or really wasteful because you might ask why—if
they just wanted to simulate us, did they bother simulating all this dark matter? Six
times as much matter, obviously, increase their CPU cost, what they had to pay for their
über cloud services, whatever. Who needed that?>>TYSON: Plus we came really
late in the universe.>>TEGMARK: But every single thing we’ve
discovered, like dark matter, for example, that seems superfluous, we’ve since discovered
that if it weren’t there we would be dead. Or, in fact, we wouldn’t even have evolved
in 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 some
interesting life? Or is there something in our universe, which
is really just bells and whistles that you could optimize out?>>CHALMERS: Someone was just doing—this
kid was just doing a science experiment. He ran a million simulations overnight, and
exactly one of those universes produced— broke the symmetries in the right way to produce
conscious beings and, hey, here we are.>>RANDALL: Why did they make chiral fermions so difficult to simulate on the lattice?>>GATES: That’s a scientific question,
guys.>>TYSON: So, Zohreh? Yeah.>>DAVOUDI: So, maybe just adding something
to this. If someone was just looking at the weirdness
that we observe in the universe, maybe more fundamental question to ask— again, we can ask why the parameters of our
universe, 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 can
sort of start to think this is just an input as many other input. Or the other way to interpret it is that we
don’t know, at a fundamental level, what’s going on. Maybe there is embedding theory
that would arise to— that is simpler. It has fewer input, or maybe
just one, and then gives you the values of the standard model and all these theories
that, no, to be exactly the same that we observe
in nature.>>TYSON: Well, just to be clear,
when we—if any of us program a computer, a simulation of anything, there’s a set
of 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. Almost
all of our codes, there’s a line that gives the value of pi that’s not tweakable.>>DAVOUDI: We don’t have any mathematical—sorry.>>TEGMARK: My sons tell me, for example,
that in Minecraft when you create a Minecraft world, I’m taught by Philip and Alexander, you
have to input a world seed.>>TYSON: Okay.>>TEGMARK: Yeah. And if you put in a different
one, different universe.>>DAVOUDI: Basically, it means that
we don’t have the mathematical equations, for example, to say that the mass of the electron
should be what we measure and things like that. So, we don’t have
yet a description as why these have these values.>>TYSON: But why should we be—this
might have to go back to David. Why should we be the measure of what an intellect
is, 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 these
physical constants that come together, so that we exist many billions of years after
the universe forms, maybe that’s just trivial for anybody who’s programing the universe.>>CHALMERS: Yeah, I mean, it probably
is trivial. They’re probably got Sim universe technology. Everyone’s running it on their desktop. I mean, someone at Google in the next universe up.>>TYSON: The next universe up.
That’s now a phrase.>>CHALMERS: Create a Sim universe by,
okay, set a few parameters around the universe. No big deal. Some of those universes produce nobody. Some
of those universes produce somebody. And those somebodies have to reverse engineer
their universe, and it turns out reverse engineering is really
hard, whether you’re in a simulation or not. But that’s just—if you look at it this
way, it’s just a matter of perspective.>>TYSON: Because when I think
of the game Tic-Tac-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 game
you 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 a
game that challenges them. And then we have the game of chess, which challenges us, but you go up an intelligence
level, and then it’s just a trivial exercise. I don’t care how many possible moves there
are. It’s trivial if the brain is a greater brain than ours. And I’m reminded, which one of you may remember—just
to correct me if I don’t get it right— was it Feynman who first analogized the laws
of nature to our attempt to understand the laws of nature would be like coming upon a game of chess
and you know nothing of the game, and you’re just watching people move, and you don’t
have the rule book. And you have to deduce what the rules are. And so pretty easily you can see, well, this
piece moves this way and this only goes diagonal. You get that, but occasionally one of the
pieces jumps two squares instead of just one. Well, why did it do that? So, you make a note
of that, right? And then later on that little piece that jumped too, it reaches the other end of the board, and
then it becomes a whole other piece. That’s kind of freaky. It’s rare, but it happens, and it’s an
important rule of the game that most of the time you don’t see. And so I’m left wondering how much of a
chess game, without the instruction manual, is the very universe in which we live. To get your answers one each from that. Yes,
Zohreh?>>DAVOUDI: Maybe starting from the philosopher side. [LAUGHTER]>>TYSON: All right, David, you
led off with that.>>CHALMERS: I would say that’s basically
the situation we’re in. We call that—this is the game of reverse
engineering the universe, and we call it science. A little bit for philosophy, too. There are clues we could get about the—we
certainly get the equations and so on, but, hey, there are clues we could get about the
grander structure. Hey, maybe at a certain point we’re going
to find one of those constants that has an arbitrary value, and find there’s a coded message in there
in 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’re
in from this perspective. The world could have so much complexity, which
is completely beyond us. And it could be that we are simply scratching the surface. But I think to do science, you’ve
just got to take the optimistic.>>TYSON: But you left me very
disappointed earlier in saying that anything— I was trying to find evidence to show that
we’re not, and that evidence that we’re not could be
put in by someone who is.>>CHALMERS: Yeah, I’m afraid—>>TYSON: So, that was disturbing.
So, I’m getting back to Zohreh’s point. What’s the point of thinking that way?>>CHALMERS: Well, you might take on
board Occam’s razor, which is if we don’t need the hypothesis that
we’re in, a simulation, then we should just do without
that hypothesis. Maybe science is going to tell us a bunch of math. It’s a bunch of equations. Yeah, that could
be combined with the further hypothesis we’re in a simulation. It’s a lot simpler if we’re not. So, Occam’s
razor at least says why bother. Then, on the other hand, you’ve got Bostrum’s
statistical argument. We might actually produce a whole lot of simulations, and have very a good reason to believe there
are a lot of simulations in the universe, at which case you can just raise the question. We know some people are in simulations. We
cannot assign at least probability of zero to us. At that point it becomes a statistical question. So, I think the standard scientific reasoning
of Occam’s razor might give some reason to reject it, but the statistics starts to maybe balance
that in another way around. At a certain point, you’ve got to start doing some math about the probabilities.>>TYSON: So, Occam’s razor
actually goes very far back, I think, to the 14th century, where it was the Earl of Occam who suggested—>>CHALMERS: William Occam.>>TYSON: —that of all explanations,
perhaps the simplest has the best chance of being correct. And that was well before the methods of the
scientific method and others. So, we’ve been using it an invoking it ever since. So, Lisa, is the universe a chess board and
we’re—>>RANDALL: So, I was very much with you
until the very end. [LAUGHTER]>>RANDALL: So, I think it is indeed true that we don’t
know the answer, and we’re just going to keep doing science until it fails. And it hasn’t failed yet. Seems to—we
make progress, and so we’re going to keep doing that. In terms of are we trying to figure out, I
actually love the idea that we’re a simulation where they actually
kind of saved in efficiency by making us not quite smart enough to figure all this stuff
out. [LAUGHTER]>>RANDALL: So, [unintelligible] a lot of it.>>TYSON: That’s a built in—>>RANDALL: But, really, that’s too
much computational power, so let’s make them a little bit dumber. But I do have—I understand it’s a possibility
there’s a simulation, but there is a problem with the statistical
argument. I mean, I think if you asked any statistician, there’s just not based on well-defined probabilities
here. And actually one of the key—so, Bostrum’s
argument would say that also that you have lots of things simulating, lots of things
that want to simulate us. And I actually really have a problem with
that. Why simulate us? I mean, there’s so many things to be simulating. None of us actually get together and say—I
mean, we simulate processes or whatever, but we mostly are interested in ourselves. I don’t know
why this higher species would want to bother with us.>>TEGMARK: maybe they don’t care about
us. They just simulate a bunch of physics, or a bunch of laws. And, hey, we came along
as a by-product.>>RANDALL: Yeah, it’s in the realm
of possibility.>>TYSON: So, we grew out of
their Petri dish.>>RANDALL: But I do think that, again,
ultimately what—as physicists, as scientists, we’re interested in the things that we can
actually test. So, to the extent that it gives us an incentive to ask interesting questions like do we see
cosmic rays at different energies, or from different directions, going at slightly
different speeds, or anything of that nature. Or do we find the laws—I mean, that’s
certainly 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, but
maybe we’ll frame—maybe we’ll be presented with a bunch of other questions. But that is—I mean, so it’s a little bit
of a systematic way of figuring out the chess game because in the case of the chess game, you have many
games. You can watch many games. Here, we have this one universe, and we can
try to make little tests within that universe to try to test laws, but those apply in those
little realms. I mean, one of the brilliant things about
Galileo was he realized there’s many ways to do science. There’s thought experiments, observations. But he actually came up with
the idea of experiments themselves. The idea that you’d simulate—>>TYSON: We’re bringing him
to the next panel.>>RANDALL: Yeah, I know. I know. I’m
totally excited about that one, too. [LAUGHTER]>>RANDALL: So, that’s just the nature of science. So,
I think we are trying to figure it out to the extent that we can.>>TYSON: Jim?>>GATES: I think you nailed it with
the chess game analogy. One thing that I think that a lot—often
times, when I talk to people—and Lisa alluded to this very well, is that a lot of people
think it’s all about them. They really do. They think it’s all about
them. They have to understand things that’s somehow related to them. It’s all about them. And I think that one
of the things that science actually teaches us is that it’s not all about us. We may be struggling with the description
that we’re trying to construct, but the universe doesn’t care whether I understand
or don’t understand. The universe doesn’t care whether I exist
or not exist. The universe, at least as I have studied it, is I’m going to retreat
into Einstein, and at the end of the day it is an extraordinary
mystery. That’s the sense that I get from having studied science for now 50 years almost. That we live in this place of mystery, and
we need to accept a humbleness about our efforts to go out and explain that chess game that you described.>>TYSON: Ooh. Max?>>TEGMARK: I fully agree with you that
the world would be a better place if we humans could be a bit more humble. At the same time, I also feel that the very
soul of physics is this audacity to look for hidden simplicity
in things. So, I think the metaphor of chess is a beautiful one. We have as a goal in physics to look at this
very complicated and messy seeming universe and look for hidden simplicity, look for rules
of chess, which are actually simple. Not the list of one googleplex different possible
things. We’re not just saying it’s all random. And, of course, we don’t know yet whether
there 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 actually
much healthier as scientists if we have this innate optimism instead of saying, well, it might be they
were too dumb to ever figure this out, so let’s just not try. I think it’s much healthier to say there
is a real possibility that there is this hidden simplicity, and, in fact, Galileo and Einstein and so
many before us have found simplicity far beyond what their ancestors every dreamt to. So, let’s keep looking for even more hidden
simplicity. Maybe this is actually all computational mathematical,
which that’s anyway the ultimate audacity to hope for that because that would mean that
in principle, at least, it really is possible to figure out the rules
of 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 actually
figure it out.>>TYSON: Thank you, Mario, for
that and, Morpheus. So, Zohreh?>>DAVOUDI: So, yeah. I would like to
deviate a little more from your question very quickly because it didn’t came up in the
discussions, but I wanted to distinguish between the idea
that we can simulate a universe, as opposed to the universe being a simulation, because there are fundamental limits to our
capacity to actually compute things. And these are based on the physical laws that
govern our universe. Basically, we can’t have infinite power, the energy, the laws
that govern basically the uncertainty principle
can limit the rate that we can process logical operations, and also the entropy and thermodynamic
laws can limit the amount of memory that can hold in a given
amount of the space-time. And things- ideas like this that were discussed
by [unintelligible] and other people, and therefore we might not be able to actually—and
there are other actually limits when you think about larger-scale expansion of the universe, whether or not it can ever casually connect
to parts of the universe. It’s expanding. And, therefore, store and process those information to be able to actually re-simulate the universe
that we have. So, it’s a different idea. I don’t think
that based on the physical laws of our nature this could be possible, but that doesn’t mean that our universe
could not be a simulation inside another universe that has another laws of physics that doesn’t actually limit the amount of
computation that is required to simulate a universe. So, these are two different ideas. But just to come back to your question, I
think as a physicist and thinking about the simulation idea, I think it doesn’t change the way I think
about the science, and I do my every day job as a scientist. I think just the notion of whether or not
we’re real or just simulated, it’s kind of irrelevant because what we are observing
is no different from being real or imaginary. We just go and discover things that we already
don’t know about the universe, that laws that we haven’t discovered. But at some point, maybe we find
some sort of more strong evidence that could connect us to a higher level that says something about whether
or not the universe is computational based and there is some simulator besides us. These are the ideas that require more thinking
and more thinking out of the box, I would say, at the moment, but maybe at some point in future when we
have more understanding of the laws of our universe, we can have more rigorous way to go and look
for 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 universe
and see what would be the consequences of those kind
of assumptions. But at the moment we don’t have such evidence, and it would be wrong to put a lot of focus
on this idea. But it’s definitely a very fun and curious idea to think about as a scientist
and, therefore, I think that’s why I do science.>>TEGMARK: I just have to alert you she
knows the answer to your chess question, and she’s just not telling us because you’re
Persian and you Persians invented chess.>>TYSON: Okay.>>DAVOUDI: Yeah. I actually played
that game when I was very, very young.>>TYSON: So, she does have the
answer. [LAUGHTER]>>TYSON: So, let me just end before we transition to
Q&A. I want to get the likelihood that you think we are in a simulation. Ten percent chance? Twenty percent? Just give
me a number. Just a number. Go.>>DAVOUDI: I can’t give you that
number. I don’t have any answers.>>TYSON: No. [LAUGHTER]>>TYSON: She’s not authorized to divulge that information. Okay, so you’re giving no answer. Max?>>TEGMARK: Seventeen percent.>>TYSON: Seventeen percent. [LAUGHTER]>>TYSON: Jim? Morpheus?>>GATES: One percent.>>TYSON: One percent chance.>>RANDALL: I’m going with effectively
zero.>>TYSON: Effectively zero. David?>>CHALMERS: Forty-two percent. [LAUGHTER]>>TYSON: Um, I think the likelihood
may be very high. And my evidence for it is just it’s a thought
experiment, and it’s simple. We’ll just end with this reflection—and
I’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 measure
to be our own intelligence, and we tend to think highly of it, getting back to Jim’s point, there’s a
certain hubris just even in how we think about our relationship to the world. And that’s understandable perhaps, even
in the search for intelligent life in the universe. It comes with the assumption that we’ll
find life that also thinks we are intelligent. Well, if we look at other life forms on earth
with whom we have DNA in common, there is none that we would rank ever in the
history of the fossil record, or life thriving today, that we would rank with us and our level of
intelligence. So, given our definitions, we’re the only
intelligent species there ever was because we have poetry and philosophy and music and
art. And then I thought to myself, well, if the
chimpanzee 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 cannot
do trigonometry. Some people can’t do trigonometry. Certainly
not these animals. So, if they cannot do trigonometry, and they have such close genetic identity
to us, let’s take that same gap and put it beyond us and find some life form that
is that much beyond us that we are beyond the dog or the chimp. What would we look like to them? We would
be drooling, blithering idiots in their presence. The smartest chimp can do maybe some sign
language and stack boxes and reach a banana, put up an umbrella, like our toddlers can
do. Our toddlers do that. So, maybe the smartest human—bring Stephen
Hawking forward in front of this other species, and they’re chuckling because they’ll
say, oh, this happens to be the smartest human because he’s slightly smarter than the rest
because he can do astrophysics calculations in his head, like little Timmy over here. [LAUGHTER]>>TYSON: Oh, you’re back from preschool? Oh, you’ve
just composed a symphony. That’s so— let’s put it on the refrigerator door. We
just 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 is
just the creation of some other entity for their entertainment. It is easy for me to think that. So, whatever
the likelihood is: zero percent, 1 percent, 17, 42, no answer, I’m saying the day we learn that it is true
I will be the only one in the room saying I’m not surprised. Thank you all for coming tonight, and thank
the panel. [APPLAUSE]>>TYSON: We will bring up the lights, and in this transition between the formal
part of the panel and the Q&A that we’ll be taking from you, I just want to tell you what it takes to run
this thing. As I told you earlier, it was formed by an
endowment 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 of
Hayden programs. We have Susan. Susan is out there. And we have Emily Haidet. She’s also part of this team that make this work. We have my executive assistant, Elizabeth
Stachow. We have Laura Jean Checki, who’s our stage
manager. [APPLAUSE]>>TYSON: We have some fans of Laura in the audience.
Good. We have Miriam Poser, who has been with us
like forever and is a die-hard supporter as a volunteer of our programs. Lydia Marie Petrosino—did I pronounce that
right, Lydia? I only ever call you Lydia Marie. Lydia Marie is good. And, of course, we have
Betty Walrond. These are people who make this happen every
single year. I just want to collectively give them applause. [APPLAUSE]>>TYSON: We have about 15 minutes for Q&A, so let’s
go straight to it. We’ll go back and forth, left and right. No one will hear you unless you speak into
the microphone, so let’s start here. Let’s go.>>QUESTION: Okay. So, my question is does
it really matter— would you view the universe differently if
we knew it was simulated? Could we do the math differently?>>TYSON: Ooh, I like that. To
make this efficient, we’ll pick one person to answer, so how about Max because your book is tilted—what’s
the title of your book?>>TEGMARK: Our Mathematical Universe.>>TYSON: Yeah. So, he’s the
guy to answer this question. Okay. If you knew, would your math be different?>>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 everyday
life? My answer is absolutely not. I feel that when we look at these rather sterile
equations or the computer code, or whatever it is that’s running this, there’s no meaning or purpose built into
that. 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 regardless
of whether we’re simulated or not. And I think this is very much the point that David
was making earlier also. We shouldn’t diss things just because they’re
simulated.>>CHALMERS: The math is a little bit
different if we’re simulated, on the other hand, because there’s also the math of the simulating
universe.>>TEGMARK: Right.>>CHALMERS: There’s a math of our
universe 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.>>TYSON: Wait. So, you’re
swaying—can you embed a complete system of mathematics within a higher system of mathematics?>>CHALMERS: Yeah. Maybe the embedding
universe 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’ll
give us input devices.>>TYSON: So, you feel like you’re
in prison?>>CHALMERS: No. it’s just like earth
is cool, but the galaxy’s even cooler.>>TYSON: Okay. Yeah, a quick one here.>>RANDALL: I think it would feel different. It’s always interested me that if you miss
a basketball game and you know it already happened, it’s less interesting to you to watch, even
though 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 be
disturbing, at least to me.>>TYSON: My analogy to that
is if you go to the Smithsonian Air and Space Museum in Washington, and you see the Apollo 11 Command Module that
went to the moon and came back, and there it is, if you made an exact replica of that and put
it on display anywhere else and say you cannot really tell the difference except microscopically, but it’s a fake, it means—it’s different
to you even though you can’t tell the difference. The knowledge that it’s really seems to
matter to us than if it’s a simulation or a model, in
that case. So, I have to agree. I reluctantly agree.
I don’t want to agree, but I have to agree.>>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 investment
in the long-term survival of our species. Our science underlies our technology. If our environment changes, we will use that
technology to survive, whether that’s true if we’re simulations
or not. That’s why I do science.>>TYSON: Are you also running
for president? [LAUGHTER]>>RANDALL: No, because they can’t talk
about science.>>TYSON: Who, by the way, Jim
Gates is on the President’s Committee of Advisors of Science and Technology, PCAST. And you’ve been there for almost the entire
administration, so keep up the good advice that you’re giving. [APPLAUSE]>>TYSON: Let’s go right here. Hey, how are you doing?>>QUESTION: Good.>>TYSON: What grade are you
in?>>QUESTION: Eighth grade.>>TYSON: Eighth grade, cool.
So, what do you have?>>QUESTION: So, you were saying about bugs
in the code of the universe, if it is a simulation. How come if it probably statistically would
not be perfect, how come we have not so far seen any corruption or glitches maybe in the far-looking
like the cosmic background radiation? How have we not seen anything that just seems
like it couldn’t be there?>>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 never
seen gravity waves either. The point is that our technology was not sufficient, and might not be sufficient now.>>TYSON: Okay. [LAUGHTER]>>TYSON: So, what he’s saying is that it may still
be there. We just haven’t found it yet. That’s a cop-out answer, I think, between
you and me. But don’t tell him that I said that. Yes, Zohreh? Yes?>>DAVOUDI: Yeah. So, exactly the line
of 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 something
doesn’t mean that we might not see something and therefore, as I said, we look for evidences
that tells us that there are some imperfection in the universe because the simulator or the amount of computation that could be
done to generate our universe has been finite, It hasn’t been infinite, and therefore, there might be some evidence. But
it doesn’t mean that the fact that we haven’t seen it doesn’t mean we shouldn’t go and
look for it. It’s been difficult, but—>>GATES: But I thought the question
was why haven’t we seen it. That’s what I answered.>>TYSON: Well, yeah. And don’t
you both agree? You’re saying if you haven’t seen it,
it doesn’t mean it’s not there. Keep looking.>>GATES: Absolutely.>>DAVOUDI: Right.>>TYSON: Good. I’ve got a
question from Twitter that came in. Evan Quinter from the Twitterverse
asked— I think I’ll direct this to Max. “If the universe is a simulation, does that
mean there’s a limit to how far our universe can reach?” Because we speak of an infinite universe beyond
our horizon all the time. So, you’re ready to say if it’s a simulation, it can’t
be infinite, and there is the limit to the code.>>TEGMARK: It’s a great question. If
we are being simulated in one universe up on finite computational resources, yeah, then either the size of our universe
is actually finite, or there’s some other trick like it just keeps repeating itself over and
over again.>>TYSON: Like the background
in the Flintstones when they’re riding in the car?>>TEGMARK: Precisely.>>TYSON: The background just
repeats. I was so angry. I said you can’t draw me a—what’s with
your budget?>>TEGMARK: That’s right.>>TYSON: Have you ever seen
the backdrop of cartoons when people are running? It just repeats. When I was a kid, that disturbed
me.>>CHALMERS: Maybe it’s a just-in-time
simulation. It’s kind of like the Truman Show or something. They started off simulating me in Australia
where I was born [unintelligible]. I came to New York, so suddenly they had to simulate
all of you guys and—>>TYSON: For you?>>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 just
reached Pluto, so now they had to simulate Pluto.>>TYSON: I see.>>CHALMERS: Just like that. So—>>RANDALL: Let’s not start with Pluto.>>CHALMERS: Start small and go bigger.>>TYSON: Yeah, don’t get me
started on Pluto, first of all. But what you’re saying is they might just
be laying down the bricks in the road as we drive along.>>CHALMERS: Yeah. Just-in-time simulation,
they call it.>>TYSON: Just in time.>>CHALMERS: Yeah. Simulate only as much
as you need.>>TYSON: Okay. Right here. Yes?>>QUESTION: Hi. So, we briefly discussed infinity
and how it relates to this topic. But I was just wondering on the other end
of the spectrum why is nothing not a thing? Is there not nothing when you come down to
the fundamental question?>>TYSON: We had an entire Asimov
panel 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. [LAUGHTER]>>TYSON: So, okay, maybe he didn’t know that, so—>>RANDALL: I actually have a probabilistic
argument.>>TYSON: Okay. So, we’ll entertain
it, but go online. The whole thing is there. It’s called The Existence of Nothing. Okay,
yes?>>RANDALL: So, in my book Dark Matter
and the Dinosaurs I have a section on cosmology, and I actually talk about the probability
of nothing. And I think nothing is just very unlikely. I mean, first of all, we wouldn’t talk about
nothing because we wouldn’t be here. But nothing is just one— if you think of a number line, zero is just
one point on it, and nothing is just—I would say it’s very
unlikely. And if you have an explanation of why there’s nothing, then there’s something there that allowed
you to have the rules to explain it. [LAUGHTER]>>TYSON: So, you’re saying
the act of posing the question of why there’s something is proof that there could not have
been nothing?>>RANDALL: Right. So, there’s two answers.>>TYSON: Okay. Crystal clear
now.>>RANDALL: That’s one. And the other
answer is probabilistic.>>TYSON: Okay. Yes, sir?>>QUESTION: Hi, Neil. How are you?>>TYSON: Hi. Good.>>QUESTION: So, I think I’m going to say
this every day now after this. I’m going to say computer end program when I wake up
in the morning. But the question is say we assume that we
are 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 and
it’s not an input from the programmer and we’re not on a holodeck within a holodeck
within a holodeck within a holodeck. You think that would be possible and maybe
escape the simulation?>>TYSON: David, what do you
have?>>CHALMERS: Well, I think we’re probably
stuck for now with the laws of the actual simulation of the simulated universe. If it’s a perfect
simulation, we’re not going to be able to do better than that. We’re not going to
get information about the character of the simulated universe. Now, if it’s a buggy simulation, or if it’s
interactive simulation—if they’re sending messages down here in the way that God was
supposed to and so on— then all bets are off. All I can say is so
far I’ve not seen evidence that we can use to make predictions, hey, tomorrow the simulators
are going to call the whole thing off. So, all we can do there is speculate as far
as I can tell. If Zohreh’s work pans out, maybe we’ll
suddenly have a lot more evidence.>>DAVOUDI: And I would add that at
the end of the day we are living in this universe. So, we are constrained by the laws of this
universe. So, the concept of escaping from this universe doesn’t seem logical to me because we are
bound to be evolving according to the laws of this universe, and not something beyond that.>>TYSON: Plus, some other universes
have slightly different laws of physics. I don’t want to be the first to visit them. [LAUGHTER]>>TYSON: Send something else then, and we’ll figure
it out. We only have time for a couple more questions, one of which I’m going to take
from our Twitter list. So, let’s go right here. Sir, yes?>>QUESTION: Sorry, Neil, I tend to disagree
with your conclusion about the universe simulation percentage, and more agree with Lisa’s zero percentage.
Here’s why. Using your chessboard analogy, yes, there
are 64 pieces on a chessboard. You can assign numbers to each piece.>>TYSON: Sixty-four squares.>>QUESTION: Sixty-four squares, right. And
you can assign values— numerical values to the chess pieces, and
then use computers to see into the number applies: 3, 4, 5, and then run the simulation, and you get the
end 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 one
person, when we have interactions of each other, we have interactions of more than each
other 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 logarithmic
rate.>>TYSON: Exponential rate.>>QUESTION: The conclusion—exponential rate.>>TYSON: Yeah.>>QUESTION: It’s going to be one conclusion,
and that is—the result is not going to be good.>>TYSON: But it may be that
these multiple interactions that transcend our native ability to compute are no different from the Tic-Tac-Toe game
being played by the five year old. We’re just too stupid to know.>>QUESTION: Well, that’s true.>>TYSON: Okay. That’s right.>>QUESTION: But, again, when you look at the
complexity and try to mathematically model seven billion people’s characteristics—>>TYSON: Yeah, we can’t do
it because we just have human brains.>>QUESTION: Absolutely. Thank you very much.>>TYSON: Yeah, sure. Forgive
the rest of the people online. The last question is going to have to be from our Twitter stream
here. 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 dark
matter—there are multiple ways you could probably get to this, but let me say how it’s
written, “Is dark matter transparent where simply
rules 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, but
we can measure their existence. Could that be the blood of the operating system throughout
the universe?>>RANDALL: So, it’s an interesting
question, and people have asked that question. And you have to take a little bit of an Occam’s
razor approach here. So, first of all, dark matter is indeed transparent
matter. It’s matter that just light just goes through. There’s evidence for it not because we see
it, 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 the
laws of physics wrong and there really wasn’t matter, and the we got the laws of physics
wrong. First of all, it’s a lot simpler to believe
this 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 no
evidence that those laws of physics are wrong. But, furthermore, there’s actually—there’s
more 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 held 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 through
it, you see the gas get stuck in the middle. You can see that through x-rays. Through gravitational
lensing, you can see the dark matter just pass through. It acts just like you would expect matter
that’s not interacting to act. It goes right through, the gas stays in the
middle. Now, you can try to mock up equations, or some simulation or something that does
that, but it looks just like matter would look. It’s exactly what you would predict.>>TYSON: Except we established
earlier 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?>>RANDALL: Well, gravity is, in some
sense, the operating system. But gravity is responding to the existence of the dark matter. And dark matter does play a big role. There’s
more of it. It collapses. It doesn’t interact with light, so it can form structures more easily than
normal matter.>>TYSON: I like that. Gravity’s
the operating system. Well, how about dark energy?>>RANDALL: Dark energy is another just
thing that’s in there that’s responding to gravity. So, dark energy is—for those who don’t
know—smoothly distributed. It’s not like matter that clumps together.>>TYSON: It’s the operating
system.>>RANDALL: It’s not the operating system
either.>>TYSON: Operating system is everywhere you touch on a computer. So is dark energy. [LAUGHTER]>>RANDALL: I’m just getting confused
now. It’s part of what I put in, at least in
my 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 of
this energy that we don’t observe directly. In some sense, we observe the fact that it
is responsible for the acceleration of the expanse of the universe. But gravity is the only law there. The other
stuff is just stuff. Dark energy is stuff. Dark matter is stuff. The gravitational equations are acting on
that, and it’s actually creating the gravitational force.>>TYSON: Well, so if gravity
is the operating system of the universe, I can’t wait for Universe 2.0. [LAUGHTER]>>TYSON: Thank you all for coming this evening. Thank
the panel. [APPLAUSE]
>>TYSON: Zohreh, Max, Jim, Lisa, David. [APPLAUSE]
>>TEGMARK: It was so much fun.>>DAVOUDI: Thank you.
>>TEGMARK: That was really—>>TYSON: Thanks for coming out.
That concludes the 17th Annual Isaac Asimov Panel Debate. Goodnight to you all here in New York. We’ll see you next year.

100 thoughts on “2016 Isaac Asimov Memorial Debate: Is the Universe a Simulation?

  • If it is a simulation (I see no evidence to categorically deny the possibility or disprove the idea) there is no point in developing methods to determine if it is, because the simulation would be programmed to control the outcome. If the universe is a simulation, then it is logical to assume that we are also simulations, as we are, as far as we can tell, part of that universe. Having said that, If there is a controlling force studying the results, then this force must be what qualifies as an entity or god like being that seems to have a wickedly sick and twisted sense of humor, to serve what purpose? If our world exists on a higher life form's laptop, that has set parameters? or is subject to randomness? The discussion is to me a bit frivolous and for the genius intellectually gifted minds that need more to stimulate their brains. Most of the world dismisses this as fantasy. Also programmed? Believing in this is pointless in the long run. "Emphasis on a useless exercise" To quote Neil.

  • In such a vast world and universe, with so many variables, if hwe lived in a simulation with so much complexity there would have to be glitches everywhere; lamps disappearing as you sit reading and things like that. It would be impossible to have consistency.

  • He always laughs like the cartoon Dog Muttley!!!, one day the history books will have to be rewritten of what they find out in 50 years from now that there was never a BIG BANG and that it was another Universe Multidimensional Universe that popped in,a membrane QUANTUM will prove this!!!.

  • Hey celebrity! Tyson, you’re just a stupid celebrity! If you were at the time of someone for example Newton, you would make fun of him for not believing in the current science of that time! Science is about discovering sometimes radical ideas! So don’t deny anything without having a reason for it!

  • I'm with Lisa Randall – 0%, Neil's elegant argument notwithsatnding. OF COURSE there is a 99.9999999999999999999999999999999999999% probability that there are beings in the universe 1% or 2% smarter than human beings. But by his very argument, trying to simulate us would be like one of those beings running the same BASIC program that outputs "hello world" over and over again. It simply wouldn't hold their interest for more than a passing thought.
    I also agree with Ms Davouti that the really interesting question here is not whether our universe is a simulation, but whether we can simulate the universe.

  • IF we are in a simulation, we cannot know anything to be true, about our own universe or about the simulators plane of existance, since truth becomes a subjective matter at that point. Therefore we can explore, theorize and extrapolate the possibility of this simulation but we cannot absolutely conclude anything about anything.
    With that being said, finite parameters and the existance of computational technology can be used to argue the possibility of a simulation. IF there is a maximum velocity, our universe is finite, and the Planck length is real, then yes, it's "possible" to simulate a universe.

  • Poor guy. Really actually Money making. At its best. She blinded me with…. baby theft. But science is a better choice. Real austere groups need money, where do they need money. Maxes fun rrrrrrrr. What date was this if Jesus wised out the vine. Most likely both side of family gone. Vine you are too full of yourself seller!

  • Justa a question … if all were together since "big something", all the mass today on black holes were there too (obviously, everything too)… So, "everthing" was a huge black hole, hot and so on the greastest begining …. Then, black holes does have an end somehow and a new universes starts from there? any sense?

  • I too just woke up to this video at 5:45am, I remember sleeping on Yuval Noah Harari, after being dosed with meds because of my mood- what have we done to humanity where this has become the norm; I'm convinced that it must change if we seek any form of a healthy conscience- in order to have a better cosmos… The writing is on the wall weather its a pyramid, holographic universe, simulation, word of God, entheogen, need I say more?

  • Always wondered if The Matrix as a movie was based upon reality which then in essence is a simulation.

  • It's odd that people so intelligent would think an afterlife in a simulation would require the simulation to be rebooted and rerun. If we are nothing but code, our code could just as easily be copied from one simulation to another as a form of afterlife. If we are in a simulation, our simulation sucks. We get fat, we get old, and we die. Not cool, but perhaps a useful tool for the purposes of the sim. However, I think from an ethical standpoint if we were able to create a simulation complete with artificially intelligent beings and we did require them to exist in such a state, we'd be ethically obligated to reward them with a new simulation upon their "death" in suckworld. I couldn't imagine creating a simulated universe with artificially intelligent beings such as ourselves without granting them an afterlife when all that would entail is copying and pasting their data file from suckworld to amazingworld.

  • What a stupid topic for so-called scientists. It doesn't matter if we're in a sim, because we'll never be able to prove it. And so what if we are? To us it's real, and that changes nothing in our quest to understand the Universe we're a part of.

  • Yeah I rather like hearing a group of number unicorn academics debating the base existence question, and basically coming to no real solution other than agreeing to my not nearly as educated and a much superior math moron's, soon to be published hypothesis essay, titled, 'Yeah I dunno either'😏

  • Wrong, I know the cause of death, as does everyone else, the leading cause of death, and in fact the cause of 100% of all deaths is life. Life is a fatal disease the is contracted at conception

  • Freddy spent many hours per day pondering whether or not the universe was some sort artificial simulation such as a vast computer program. But the definitive proof needed to prove that it was had been intentionally omitted from the original code by the *Great Programmer*. Ergo, infinite loop pondering was all Freddy's brain was capable of doing for the simple reason it was impossible for him to have a thought that hadn't already been compiled eons ago.

  • somebody says that our world is not real it's a simulation, the other one says that our world is running by the organisation named illuminati they humiliate us they control over us, and the one who says that we are not real only a program and nothing else there is nothing real etc….my question is why they want to confuse all of us?
    what's the purpose?
    who we are? what we are?
    what is real what is reality
    #after watching these videos about simulation world, the illuminati community, and the video game world….i feel like i hv lose my control over me i can't even imagine a single thing clearly i don't know where i am and why am i here?😣😣😣😣😣
    this is really too much bro…..these videos seriously depressed everyone till death.
    ##this is not an entertainment this is a serious issue##

  • Maybe debates like this led to such simulations, in the past, on a lateral timeline, creating a manifestation of a simulated destiny, and we are currently experiencing the simulation to see if its a good idea

  • How do you separate simulation from paradigm of existence ?
    Or a communal subconscious paradigm of existence ?

  • To me, it is ourselves, our collective minds, also aliens minds, and so forth, that's been programming our universe, our own reality…

  • I like this topic, as it is consistent with Yahweh's plan to test souls before welcoming them into a far greater and eternal reality.

  • We all love Asimov, but tyson is a putz. It's an insult to his memory to have this idiot as a host.

  • While this is a fascinating subject and an enjoyable discussion… please oh please stop constantly making statements in question form? It really does get annoying?

  • The key in this is also how you define simulation. How someone would define simulation in 1943 wouldn't be the same as in 2020 which won't be the same in 2100.. The second thing for me is really this is a search for an intelligent design. Mario could see the laws and the intent inside the code, he could possibly track or figure out that the machine code which his world was designed by shows some kind of purposeful or intelligent design.. The matrix theory is still a quest to figure out why are we here and did something create us. If you can take a theory like the matrix with some level of seriousness, then it would make you a hypocrite to scoff at religious belief… The scientist, the theologian, and the Philosopher could all come to the same crossroads in the end.

  • I often wondered why it is that the things people come up with in sci fi movies end up being not so un real.
    Maybe things such as creativity have a correlation with what is reality because all thinking is done using a brain that is based on the rules of quantum mechanics.
    So maybe our thinking is guided by the quantum world more than we realize 🤔

  • Could dark energy be something similar to lagrangian point between galaxies? I’m an idiot so maybe someone can understand what my monkey brain is trying to describe.

  • well it's proven that in our known universe there are not enough atoms to sustain a computer program simulating the universe, so that means we can not simulate our universe in the future. which means there can't be endless simulations. if we were living in a simulation, the world outside it would be superior with unknown power to sustain such a program. So that means we're an extra terrestial creation, not even made on a computer because who knows what kind of technology they have, more likely to be hologrammed as Stephen Hawking claimed.

  • It is easy to understand we are not a simulation due to no measurable latency at any nested level of logic, in our real world

  • So, someone programmed us and We're The Sims, who us, the sim creatures then made a game called The Sims about us. That's like putting a box in a box.

  • I went to bed watching videos about computer programming, had two nightmares and woke up to this. The algorithm of Youtube's predictive suggestions is weird. "Computer programming"/"is the universe a simulation"? Yeah, I see the connection… only if the universe is The Matrix.

  • Have you guys checked out Doelow Pilotman metaphysics playlist on YouTube? He's mixed science with spirituality. Check him out🥰

  • War, poverty, have and have nots etc are elements of the equation. Reality does exist due to emotions and racist views of only European discoveries. Simulation exist in a controlled environment like the program/simulation of slavery.

  • I just watched this, and want to add one point:

    Think of a rubrix cube. There are certain problems to be solved on a cube that may require for example at least 9 moves to solve. BUT, that does not mean that using these 9 moves solves the problem the fastest. Alternative solutions taking perhaps as much as 11 moves may solve the problem even faster by the simplicity of the handling of the cube. In simillair ways, the programmers of our simulated universe may have laid out an alternative route to solving the same fundamental problems/equations. A route that saves them energy. And this alternative route can also explain asymmetry. And it can even be a shortcut that allows for asymmetry. For example if the rubrix cube solver removed a few color stamps and replaced them. So he cheated. For example allowing for maxwells equation. But we have no way of knowing the fastest 9 step moves to solving the cube as long as we live in a simulated world where the 11 steps are being used. Or vice versa, the 11 steps, if the simulation uses the 9 step method…

    Also, the presumption that there would be bugs is wrong. And the idea of the programmers always being one step ahead of us is also wrong. Simply because of how spacetime is merely a part of the simulation. So at any time, any observer (us) hooked into the simulation could go into Thomas Jeffersons body and experience his life from his point of view. Deterministic. So there would be no bugs. If there were one, it would have been fixed long time ago. In time in the programmers universe (or simulation). Not in our fictional spacetime… And the velocity C (light) would presumably for example go slower and slower on every simulated level in order to both save energy, and because the higher simulated universe already has a restricted lightspeed C. Limiting their own energy gathering options.

  • the word it is noble words/worlds double u-lord wanna be a cowboy george gamow least square isquare need a light ground zero dr jung agni/ignatius must be.simulation

  • cern ialce through the looking glass house of cards Humpty dumpty word it is noble. words/worlds double u-lord my world line george gamow wanna be a cowboy. God didn't make little green apples. cern ialce geneva

  • And if the universe is a simulation, so what then? And if you want people to take you seriously and connect in a professional setting, please don't where sunglasses lecturing indoors. Those light aren't bright as the sun. It sets the wrong type of environment.

  • We are not in a simulation simulations wouldn't have pointless things like when someone gets a hangnail or even dandruff it would be pointless to have a simulation go that deep we are not in a simulation simulation is wouldn't have pointless things like when someone gets a hang now or even dandruff it would be pointless to have a simulation go that deep

  • David Chalmers "Level 42" statement at 25:29 was the best moment in the whole debate tying in the hitchhikers guide to the galaxy's ultimate answer to the question of life the universe and everything. Of course this is without asking the ultimate question because you can't have the ultimate answer without the asking the ultimate question. Douglas Adams is a genius……………………………….

  • Neil DeGrasse Tyson will KEEP
    his job at the Natural History Museum after staff completed an
    investigation into sexual misconduct allegations made by three women,
    and another who accused him of rape when at university together. What a
    creep, liar, fraud, and satanic troll.

    The TV host, 60, was accused of behaving inappropriately by two women in 2018
    A third woman alleged Tyson raped her in 1984 while at university together
    A museum spokesman said based on their investigation he 'remains employed'
    'Because this is a confidential personnel matter' they would not comment further
    Married dad-of-two Tyson denied the allegations in a December Facebook post
    The astrophysicist will now keep his job as head of the Hayden Planetarium
    He was cleared to return to the air by Fox Broadcasting and National Geographic

  • Very varied panel. Even if we can see stars, planets, galaxies through our own eyes, a telescope or even binoculars gazing the moon ´s surface, all that we see is definitely a simulation, not a physical simulation but a simulation created by our senses which through our "sight" determine the quality of this image formed in our brains of something that "supposedly" exists; that which fades when we close our eyes keeping just in memory the image.
    So in reality what we see is an image of something which has a physical form that when we touch (an object, form or materials on the moon) they become a reality of what we see, then we subject the element created in our brain to something that has a form type and according to our senses is real. What may happen in space is that what we see through telescopes could be a simulated image of something that is not physical because it is in another dimension
    that is NOT in our dimension. I believe this concept is nos present in our culture because we have not had such an experience, yet or even comprehend it.
    Simulations can only be created in our minds of "existing or unexisting forms, ideas, etc., and become real when we as humans create them, in industry, science, and material modifying through physical changes.
    Very interesting topic because it deals with reality and multi-dimensional space.
    What about death? I really believe that we are born again after death and that we enter into either the same or another dimension in our multi-dimensional space casually or on purpose without any intention or memory of our previous life.

  • Great talk and fascinating topic. To my mind, our universe is a "simulation" only in the sense that the nature of the Nothingness is *the original highly unstable symmetry*. An infinite number of "simulations" forming as that initial symmetry breaks in an infinite set of dimensions. Most are unstable and don't last very "long" or become featureless. Only a few evolve into stable spatial and time dimensions with the specific constants that lead to interesting worlds with life forms that gaze up and wonder.

  • I miss discussion of the essential necessity to run the simulation. What constitutes this running , and why does it only then generate a sim.universe and how does that happen?

  • After you watch this, check out Tim, the guy on the left, in this video.

    His work when we was younger.

  • Veo estas maravillosas sabias personas, y hago un comentario en mi pensamiento, escucha y mira, padre como tus hijos tratan de decifrar tu travajo, hablar de un universo inteligente es hablar del creador (el padre) decir, que al universo no le importamos nosotros, es como decir que a nosotros no nos importan nuestros hijos, pero asta cierto punto tiene razon, al creador no le importa el cuerpo material, pero le importa la energia (espiritu) eso me consta. En esta vida y la siguiente quedate en la luz. Ramon Sandoval.

  • Neil the establishment preacher of garbage religious science belief with no proof and ridicule what’s not mainstream even if there’s proof .

  • 1:47:30 We may have already seen bugs and glitches. Could explain why countless people, including James Earl Jones himself, remember the famous quote as, " Luke, I Am your Father!" Instead of the actual quote, "No! I AM your Father!" But hey, I guess James Earl Jones is just misremembering and suffering from a simple case of confabulation. Lmao

  • That Zohreh Davoudi just strings words together trying to say something profound when in reality it's bimbo talk meaning very little ..

  • I was looking forward to viewing this , then the MC made fun of the topic ?? way to get the crowd to leave Neil , you closed minded twat .

  • Well going off the probability argument that we are more likely to be part of a simulation. It is also more likely that we are a simulation created from an already existing simulation. Therefore we weren't created by anyONE, but instead another computer program. So by this our parameters dont have to make any sense because a program can create parameters for simply no reason at all.

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