2011 Isaac Asimov Memorial Debate: The Theory of Everything

2011 Isaac Asimov Memorial Debate: The Theory of Everything - Transcript



Neil deGrasse Tyson (Frederick P. Rose Director, Hayden Planetarium, AMNH):

Welcome back to the - what is now our 10th anniversary of the Isaac Asimov Memorial Panel Debate. I'm the host and moderator, Neil DeGrasse Tyson at this institution - thank you.

Here at the American Museum of Natural History, I serve as the Frederick P. Rose Director of the Hayden Planetarium. Frederick P. Rose was, he was a great philanthropist. The entire Rose family, in fact, have transformed the landscape of the city in ways that have brought cultural enrichment to us all. The Rose Center is just one example of them. Part of that philanthropy that was going on at that time involved a way to remember Isaac Asimov. Isaac Asimov is no stranger to readers out there, author of more than 600 books. He was a New Yorker. Did much of his research in the halls of the American Museum of Natural History, availing himself of our library system. And, as a fitting memory to his legacy, his wife, Janet Asimov, and friends endowed this series, the Isaac Asimov Memorial Panel Debate.

This is our 10th year, but of course that makes it our eleventh panel. You do the math, that's how it comes out. I want to thank Janet Asimov and the Asimov family and friends of Isaac Asimov for enabling this, what has become one of the most successful programs of this institution. I want to publicly recognize them for this.

We have elected in this 10th year, 10th anniversary of the series to reprise the subject of the original Asimov panel debate. That original debate was on theories of everything, specifically, string theory and what string theory is, what it means. How far has it come, how far will it take us. We thought that over these 10 years, maybe we should check in on string theory, see how they're doing.

Oh, by the way, I meant to publicly recognize that we have 300 overflow attendees to this event in an adjacent room. I just want to say hi to them. There we go. Not forgetting about them, as well.

So we're going to revisit this subject. We have two members of the current panel that were on the original panel. That'll sort of ground us with a 10-year baseline. But we have some new people to bring to you, people who have new ideas about what should be going on on the frontier of physics.

I'd like to lead off introducing Dr. Lee Smolin. Lee, come on out. Lee Smolin. Lee Smolin is one of the founding physicists of the Perimeter Institute of Toronto, an institute that specializes in the fundamental principles of physics and how they might need to change to give us an understanding of the world that we all hope and expect to have.

Next-where am I going here? Got my sheets backwards. Hang on. There we go.

Next is Janna Levin. Janna, come on out. Janna Levin is professor of physics and astronomy at Barnard College of Columbia University. She's a specialist in the early universe, especially higher dimensions and what that means. Higher dimensions always confuses us all, so we're going to find out if she can straighten us out and find out what that has to do with theories of everything.

Next up...where are here? There we go. Marcello Gleiser. Marcello Gleiser is professor of physics and astronomy, Dartmouth College. We'll find out a little later that I think he actually throws the whole concept of a theory of everything into question entirely. We'll see where that lands.

Next up, no stranger to this stage. He's one of the original first panelists of the Asimov Debate-Jim Gates, professor of physics, University of Maryland. Jim Gates, come on out. A deep thinker on all matters from the frontier of physics. I always enjoy conversations I have with him by email, by phone and in person.

The fifth of our six panelists is Katie Freese. Katie, come on out, Katie Freese. Professor of physics at the University of Michigan. Katie Freese is an expert on the early universe and especially dark matter and other exotic phenomena that none of us understands. And last and certainly not least is our sixth panelist.

Our sixth panelist coming in via Skype. Via...Skype. There he goes. Can you hear me...?

Brian Greene (professor of physics, Columbia University):

Yes.

Tyson:

Many of you recognize this gentleman-Brian Greene, welcome back to the Isaac Asimov Panel Debate. It's been 10 years and you look marvelous.

Greene:

Thank you.

Tyson:

So, Brian, I want to lead off with you. It's been 10 years since we had you on this stage. What-actually, no, before we start, just tell me, remind people who you are and what you're interested I and why we might have even asked you to be on this panel at all.

Greene:

Well, first, I just want to apologize for not being there in person. I had meant to be, but something came up. But I do realize there are some advantages of actually not being there in person. You know, should Neil wildly gesticulate, I'll be the guy that gets hit. Should anybody say anything that makes me want me roll my eyes, I can actually do so while still being completely polite just by pulling the curtain right across like that. And, finally, this is the first event at the Museum of Natural History I've participated in without wearing any pants.

Tyson:

Brian, later on we'll be asking for data on that. Something string theorists are pretty shy on providing, but go on.

Greene:

[unintelligible] data. But, you know, I have worked on string theory since I was a graduate student back in 1984, '85, '86. And I think that perhaps is part of why I'm here. And I have a view of where the approach to unifying the laws of nature has been and where it's going, and I look forward to sharing it with the panel here this evening.

Tyson:

So we'll come back to you on that, then, if you think that's headed at all in the right directions. Because I know we have panelists that think it's-the directions it's headed might not be the right way. So we'll certainly have a vibrant conversation about that. Katie, can you introduce yourself to us all?

Kathleen Freese (professor of physics, University of Michigan):

Yeah, I'm a particle astrophysicist, and I'm not used to being the pragmatist in the group, but I work on the dark side. So, the dark matter, the dark energy, dark stars. And, in my view, the theory of everything needs to provide answers not only to questions about the four forces of nature, but also about the content of the universe-its dark matter, its dark energy. In fact, this is one of the central questions of our time as scientists and we're fortunate in that it looks like some of these answers are beginning to come in.

So, in my view, the theory of everything needs to tie together with the experimental results we're starting to get out of the dark matter and dark energy regime. So, to make sure everybody knows what this problem is, when you think about the chairs that you're sitting on, the air that you breathe, the walls in this room, the planets, the stars-all of that, all the atoms in the universe, all the quarks, all the leptons, all that adds up to only 4% of the universe. And we don't know what the other 96% is. So that's what I work on.

Tyson:

Wait, do you work on the 4% or the 96%?

Freese: The 96%.

Tyson:

The 96%, okay. So you're steeped in abject ignorance, that's what you're telling me. Okay. We'll get back to you on that. Jim.

Jim Gates (professor of physics, University of Maryland-College Park):

A standard candle. But then it's not looking as bright as it should. And so the interpretation is, well, it's because the person holding that lightbulb is running away from me. So the accelerating universe would be an explanation and we call this, out of ignorance, the dark energy, this negative pressure that drives this acceleration. 

But we should keep in mind that everything should in the end be grounded in what we can measure of reality. 

Levin:

But can I just say, Marcello, that we have had incredibly successful examples of unification. Obviously, certainly our understanding of matter is more or less unified in an incredibly successful model, where we understand that light isn't different from-electromagnetism isn't different from weak forces or strong forces. Where do you draw the line? Would you have drawn the line before that great success? Would you have said, we shouldn't be thinking about unification of matter? We'll never get there and it's just too much to expect?

Tyson:

In other words, Marcello, a hundred years ago, what would you have been saying?

Gleiser:

I would have been saying that unification of electromagnetism is not perfect. Only in empty space. And that is true. If you look at the-sorry about this, guys-if you look at Maxwell's equations that basically describe how electromagnetic waves propagate in space, they are beautifully perfect, symmetric whenever you don't have any sources of electricity and magnetism. If you look at, you know, sources, they're not perfect anymore. And just to make a comment about this, yes, we have unified and I think the tendency of unification, of simplifying our knowledge of nature is absolutely key. That's what we all want to do, that's what we like to do.

Tyson:

But?

Gleiser:

And in fact, the standard model, which is what Janna is talking about, is a magnificent achievement in which we can describe everything that we know of particles, you know, in terms of 12 particles. And that's just beautiful. However, it's not a pure unification in the spirit that, say, superstring theory would like it to be, because each one of the forces-electromagnetism, strong and the weak interactions-keep their imprint in the theory. And what we really want in the so-called Grand Unified Theory, or GUT theory, is that these three things become one. And the standard model certainly does not do that. It's really bringing them together in a sort of a patchwork way. And that is in fact one of the reasons why want to go beyond that. That's one of the motivations for string theory.

Tyson:

Jim, have you gone beyond that?

Gleiser:

[unintelligible]

Gates:

Well, it's been very interesting sitting on this stage and listening to my colleagues. But-and I am far from experimental physicists as you can imagine, but this is why experimental...

Tyson:

Which means you're a theorist. Yes.

Gates:

Something like that.

Tyson:

Okay. It's code for "I'm a theorist."

Gates:

Exactly. But my point is that it is always the case that it is our experimental colleagues that prevent us from forming a religion. Because it is always grounded in what they can measure, as Marcello keeps coming back to. And so, although people can express either enthusiasm or dismay about where we are that the given point in time, I think that we need to be a little more humble and to understand that the process that we engage in is a constant flight from fantasy about what we would want to happen. And we query nature for that and that query goes through experiment. So, although this has probably been very entertaining for my audience here, I think that, at the end of the day, we have to keep grounded in: it's got to be about things that affect your lives and those things are measurable things.

Tyson:

So where has this pursuit taken you?

Gates:

Oh, my god.

Tyson:

Where have you landed.

Gates:

Why would you ask that?

Tyson:

I'm asking that here and now. It's New York City. It's March 7th.

Gates:

Well, partly it's taken to this very strange images that are behind your head right now. These are pictures of equations. I've been for the last 15 years trying to answer the kinds of questions that my colleagues have been raising. And what I've come to understand is that there are these incredible pictures that contain all the information of a set of equations that are related to string theory. And it's even more bizarre than that, because when you then try to understand these pictures you find out that buried in them are computer codes just like the type that you find in the browser when you go surf the Web. And so I'm left with the puzzle of trying to figure out whether I live in the Matrix or not.

Tyson:

Wait, you're blowing my mind at this moment. So you're saying-are you saying your attempt to understand the fundamental operations of nature leads you to a set of equations that are indistinguishable from the equations that drive search engines and browsers on our computers?

Gates:

That is correct. So, the...

Tyson:

Wait, wait. I'm still...wait. I have to just be silent for a minute here. So you're saying, as you dig deeper, you find computer code writ in the fabric of the cosmos?

Gates:

Into the equations that we want to use to describe the cosmos, yes.

Tyson:

Computer code.

Gates:

Computer code. Strings of bits of ones and zeros.

Tyson:

It's not just sort of resembles computer code, you're saying it is computer code.

Gates:

It's not even just is computer code, it's a special kind of computer code that was invented by a scientist named Claude Shannon in the 1940s. That's what we find very, very deeply inside the equations that occur in string theory and, in general, in systems that we say are super-symmetric.

Tyson:

Okay. Time to go home, I think. Where are we going to go after...? So, are you saying we're all just ... there's some entity that programmed the universe and we're just expressions of their code?

Gates:

Well, I didn't say that.

Tyson:

Like, the Matrix? That's what you said.

Gates:

Some of those codes are showing on the screen behind you right now. They don't look like codes, but these pictures, which we call "adinkras" are graphical representations of sets of equations that are based on codes. So this is, in fact, to answer your question more directly, I have in my life come to a very strange place, because I never expected that the movie The Matrix might be an accurate representation of the place in which I live.

Smolin:

Jim, may I give you an argument that we don't live in the Matrix?

Tyson:

PLEASE. Yeah.

Smolin:

Very simple...

Tyson:

Give me one now, quick.

Smolin:

Very simple argument. There's a property that the real world right down here has that no mathematical equation has and no solution of an equation has, that no-okay? That no abstract object has. Here in the real world it is always some moment which is one of a series of passing moments. A mathematical equation doesn't have a flow of time in it. It just is. And this means...

Gates:

But, Lee...

Tyson:

Wait, wait, let him finish. Wait, I need him here and now.

Smolin:

This means that, to me, that the ancient metaphysical fantasy that we, quote, are just mathematics, cannot be true. Because in a world that was "just mathematics," there would be no moment of time.

Tyson:

Why isn't there...?

Gates:

Lee, Lee...

Tyson:

..math as a function of time?

Gates:

I'm sorry...

Tyson:

These are differential equations.

Gates:

But Lee, Lee...

Smolin:

But then you lay the solution out...

Gates:

Lee, Lee, Lee, you're mistaking-you keep using the word "is" and I'm talking about the word "describe." You see...

Smolin:

"Describe" is fine, but then...

Gates:

No, no, but let me finish, please, since we started with my discussion. The point is that I ... it's fun to talk about some deep, metaphysical essence that sits behind physics, but for some of us it's about trying to find the most accurate way to describe where we live. So my statement is that in the description of our universe, that is a super-symmetrical universe, which we're going to test in the LHC. If you believe that description, I can show you the presence of these codes. That's my statement.

Smolin:

That's beautiful and that's fine and I admire that. Seriously, that's fine, that's another beautiful piece of mathematics that may be explanatory or descriptive of physics, but that all I'm objecting to is that doesn't mean that we live in the mathematics. That means the mathematics is just descriptive of an aspect of the universe and...

Tyson:

That's a good point, let me follow that one up. Jim, Jim, just because-who was it? Eugene Wigner, who commented on the unreasonable effectiveness of mathematics that we just invent in our head-yet the universe follows-can be described mathematically. Mathematics is the language of the universe. Brian, math gets-math is your tool. So should we be amazed or depressed by what Jim tells us here?

Greene:

I can't really comment on what Jim says. I find myself in the unusual position of feeling rather conservative on a panel when usually I'm sort of at the outside [unintelligible].

Tyson:

And, by the way, the pictures Jim showed all look like Spirograph images from your kid's thing.

Greene:

I saw them, I saw them, I don't know enough about to comment. But there is an interesting question, the one that you raised, about whether math is a descriptive of the universe or we are the math or what's the role, the math [you] discovered is invented. I mean, I had a conversation-and I think you may have been involved in it, if not mistaken-and the question was, is math the right way of going about trying to find deep, physical law?

And I said, look, I can imagine one day we'll encounter aliens and they'll say to us, okay, show us what you've got to describe the universe and we break out our mathematics and they look at it and say, Oh, man, we used to do that. Ultimately, a dead end. You know, and then they show us what they have found.

Now, the problem with that is I don't actually even know what I would fill in regarding what they would show us. Because to me mathematics is really the language of pattern. It's self-consistent ways of embodying pattern and that's ultimately what we do. We're pattern recognition machines. We try to codify the patterns we see in the world around us in math and in that way we try to describe the universe around us. Does that mean we are the mathematics? I don't know. It becomes really hard to really know exactly what that means, but we have found that math, so far, is a potent tool for making predictions that we can test and confirm. And that's why I follow this particular trajectory.

Tyson:

Brian, we're going to have to very shortly go to questions from the audience, but I want to come back at you with a couple of questions that are sort of purposefully blunt. Okay?

Greene:

Yeah.

Tyson:

So, you guys have been at this string theory for running on two decades now. And Einstein, working alone, went from special relativity to general relativity in 10 years, working alone. And it was a brilliant piece of work and there was an experimental verification four years after he came up with the idea. Here you have legions of string theorists working two decades and you're sort-of not there yet. Is there just not enough of you? Is there-are you chasing a ghost? Or are the collection of you just too stupid to figure this out?

Greene:

I mean, I think it's pretty clear it's the latter. Hello, you know, Einstein was a singular genius and making comparisons with him I think is perhaps not that representative. But putting that to the side, look. The questions that Einstein was trying to resolve, however deep they were, were still within a realm that was experimentally accessible within a couple of years, a couple of decades at most. We are ambitious. And we are trying to make a big leap to try to understand the universe on fantastically small scales and fantastically high energies.

Why are we so ambitious? Because we have been so successful theoretically to date that the open questions in this line of research are the ones that we're now focused upon. They're much harder to test and therefore we don't have the guidance of experiment to nudge us this way or that as much as in the past. Now, if we could solve these questions I think we'd be answering some of the deep mysteries of the ages. Do you say, well, you haven't cracked it in 20 years, so it's time to give up? No, I think you say, if progress stalls, then you go and look at other directions. But as long as progress is carrying forward, and it is, you keep going and try to figure things out. You can't put a timeline on it.

Tyson:

I think your pace of progress is sufficiently slow that it has led to these other ideas exhibited on this panel. [TALKOVER] slow that Jim is finding that we live in a matrix. And that Marcello is questioning the whole idea of a unified theory.

Greene:

Yeah, so I do worry about some of the things said on this stage maybe [give me] the wrong impression. But the bottom line is this: You have no capacity, as far as I know, to judge progress in the field unless you're actually deeply reading the theoretical papers in the journals. Are you doing that?

Tyson:

No. I presume members-I presume that we got people here who ... That's why I brought the panel here. That's why I brought this panel here. And apparently they're thinking up other stuff now because string theory is not satisfying them on some level.

Greene:

Look, let me just say this. We have made great progress and that I really think is not disputable. Have we solved all the key questions, have we tested the theory, those are the most vital things? No, but we united gravity and quantum mechanics at least on paper. On paper, have unified all the four forces. We've incorporated key breakthroughs from the past that are now well understood within the context of string theory. We've been able to cure space-time singularities of particular sorts within string theory. We've understood black hope entropy within string theory. The mathematical contributions of string theory are absolutely unassailable.

Tyson:

He's on a roll.

Greene:

Time and time again we've had great contributions. So to say there's no progress-c'mon, man, that's just not right.

Tyson:

Okay, all right ... While people gather to the microphones at the front of the stage, let me just get a quick reaction to Brian. Janna, we haven't heard from you in a bit. Quick reaction to Brian.

Levin:

Well, you know, I

Tyson:

...I invite you to come to the microphones.

Levin:

I agree with Brian mostly because his office is three doors down from mine. No, I do, I agree with Brian in the sense that progress is being made, but we all have to pursue other directions, occasionally think in a different direction than-I can't say string theory is the mainstream, but then the flow of ideas, there's always going to be new ideas that come on the table. I don't think you can judge progress in terms of human scales. Nowhere is it written that we have to solve problems in one human lifetime, that we won't have to work on problems for hundreds of years. This might be the first time that it's really been documented like this. But I don't see why we should be shocked that solving incredibly challenging problems may take more than one human life span.

Tyson:

And I confess, Brian, in spite of my diatribe there, I agree with Janna. There were some problems in the history of astronomy that took millennia to solve, so I'm getting on your case...

Greene:

I know, Neil, come on, man, give me a hug.

Tyson:

See, I could just unplug you, you see. I got real power here. Katie, where are you on this?

Freese:

Super symmetry. We haven't talked a lot about supersymmetry, which is an important ingredient in string theory. And there are aspects to it that come over to cosmology and are extremely testable.

Tyson:

So these are extra particles added to the model that we have for particle physics that explain some stuff that right now we can't explain.

Freese:

For every particle we know about, there's a new partner. So, for example, for the electron there would be the selectron.

Tyson:

Selectron?

Freese:

Selectron, with the "s" of supersymmetry in the front. Or the photon becomes a photino.

Tyson:

Okay.

Freese:

And all of these particles decay to lighter ones-decay, decay, decay-until at the end you get to the very lightest super-symmetrical particles and those could be the dark matter. In fact, they're the strongest candidates for dark matter and one of the reasons, one of the major motivations for building the LHC, so the LHC can find...

Tyson:

Dark matter particles.

Freese:

Yes, and supersymmetry. And then dark matter detectors are currently-they're underground, underneath the Apennines in Italy. They're all over the world. They're in deep underground mines in the United States. And they're looking for super-symmetric particles to scatter off of the detector and then you look for the little bit of heat deposit and every single one of these experiments that has happened in the last two years has seen anomalous, unexplained results. So.

Tyson:

That could all come together soon.

Freese:

Yes. So many Elena Aprile at Columbia University, she's the leader of the Xenon experiment and they're going to release data very soon and that's the best bet that we're going to solve this problem.

Tyson:

And you're in business. Then it's no longer an exotic particle. And you're done.

Freese:

And if there's indication of super-if supersymmetry is right, well, that is one of the key ingredients in the building of string theory.

Tyson:

Marcello.

Gleiser:

However. If you look at the data coming out of the LHC in the last two months, it's restricting the parameter space of supersymmetry...

Freese:

Not much, no.

Gleiser:

A whole lot.

Freese:

No. That's mis-it's misleading.

Gleiser:

I would say that…

Freese:

Their abstract is misleading.

Tyson:

You're both interpreting the same research paper differently.

Freese:

Yes.

Gleiser:

Yeah, obviously.

Tyson:

Jim?

Gates:

Well, all I want to say is that you need to understand that a large part of the discussion here tonight, and in fact reminds me of the story about the blind man and the elephant. You know, they each feel a different part and think it's a different creature. I have a sense that that's likely what's going on in a lot of the discussion.

Tyson:

That the universe is an elephant.

Gates:

Well, yes, and that we're blind.

Levin:

Written by the matrix.

Tyson:

We're blind.

Gates:

And so the thing that I told you about information, ultimately that would actually become part of string theory, not something different. If string theory is correct, this will be part of it.

Tyson:

I want to go to the audience right now. In order to make this efficient, because we're a little long, you direct your question just to one of the panelists. Not to get a comment from all eight of you, no. One panelist. And try to be efficient in your answers. Go.

Question:

All right, this one's...

Tyson:

Oh, I remember this, he was a little kid coming to Hayden program. I didn't even recognize him. Are you in college yet?

Question:

MIT.

Tyson:

MIT-he's at MIT. Well, congratulations. He's been coming since he couldn't even walk.

Question:

This one's to...

Tyson:

Wait, shouldn't you be in school now?

Question:

Shh.

Tyson:

All right.

Question:

This one's to Gates, with apologies to Robert Frost. Some say the world would be written in pearls, some say in lisp. So, that aside...

Tyson:

You better apologize again to Robert Frost for that one.

Freese:

You better watch out, he's at MIT right now.

Question:

I'll see you there.

Gates:

I'll be looking for you in the Infinite Corridor.

Question:

[I'm in] the Admissions Office. Anyway, are there any-do you have any predictions in your ideas or any ways to test any of your ideas any more than, say, the guy over on the screen?

Tyson:

You can take the blue pill or the red pill and you'll find out.

Gates:

I took the red pill. The work that I'm doing is in fact so theoretical that we don't understand whether it is even possible to complete the program. We have found these strange grafts. We know that they are equivalent to equations. And we have found in these equations computer codes and so that's where we are right now. So I cannot give you a prediction. This work is less than two years old.

Tyson:

But you ... but it's not that you never ... you recognize that you will need a prediction in order to...

Gates:

As someone recently asked me, said, well, you don't care about experiments, do you? And I said no, that's exactly wrong, because you see I have spent my career as a researcher worrying about supersymmetry. I would want to see an experiment before I shuffle off this mortal coil so that I'd know that I did not waste my entire professional life.

Tyson:

Good with that, okay. Right here.

Question:

I guess my question's for Lee. It seemed like towards the end you were talking about coming to the point where you either change the science or you go to a multiverse theory. And it almost seemed like you were called out by Kate, as though, oh, no, not multiverse theory, like it's a copout. And is it or is it not? That's really what I want to know, I want to hear a little bit more about that from you on that.

Tyson:

So, is a multiverse a copout?

Smolin:

My view is that it doesn't-and there's so many things that we've mentioned here that we could have a long discussion of at very different levels, so. But my view is that it's very unlikely that the kind of multiverses which have a larger, infinite number of universes simultaneously with no common chains of descent, it's very unlikely that those will lead to testable predictions that are successful. And I know that there's disagreement and I know...

Tyson:

That doesn't mean that it's not true.

Smolin:

No, no, no.

Tyson:

Okay.

Smolin:

Science is not about what's true or what might be true. Science is about what people with originally diverse viewpoints can be forced to believe by the weight of public evidence. So.

Tyson:

I gotta give him app...that was good. That was good.

Smolin:

So my view is that, and this is, I should confess in work with Roberto Mangabeira Unger which is in progressive, and it's also inspiring a lot of my current scientific work, I'm interested in the idea that the universe is just that which we see already most of. And that the-and taking seriously Charles Sanders Pierce maxim, which I did in my first book, Life of the Cosmos, was proposing a cosmological scenario in which the explanation for why these laws did arise to akin to natural selection, and thinking about that more seriously and more deeply in the last few years, it leads me to think a lot about the nature of time and the question of whether time is emergent, as many people in the quantum gravity world have proposed or whether just space is emergent and time in some sense is really, really real is not emergent, and whether, if laws evolve and time is really, really real, whether there are new opportunities to do plain, old-fashioned science, the way that Katie was saying.

There's science where we make predictions and we widen our understanding and we widen our knowledge because we're able to make predictions which are verified successfully. So that's in a nutshell.

Tyson:

That wasn't a nutshell, that was a coconut shell or something.

Smolin:

Anyway, thank you.

Tyson:

Okay, next question here.

Question:

Okay, first I feel like maybe a little emotional closure on the debates if you could kiss the back of his video head? Anyway, the question is, just for fun, and if anyone wants to answer it, maybe no one does, sort of in the spirit of Isaac Asimov: So, forgetting LHC, forgetting even Xenon experiments, if there's something that you could go to and measure, forgetting the continuity of space-time, what might you measure to get the deepest insight that you might want to see about the universe? Does that make sense?

Smolin:

Sure.

Tyson:

Let me go to Marcello. Marcello, you take that.

Gleiser:

Jeez. I'd like to see gravitons. If I could see a graviton, then I would be fore sure convinced that gravity has to be described quantum mechanically. Because, you see, right now we are so confused about what gravity is all over again that there are some proposals out there that gravity may not be a force like the other forces, which goes very much against the spirit of superstring. And so, if we saw a graviton and [were] a quantum particle like a photon, that would be great. And if it were a chiral graviton, then I'd be a very happy man.

Tyson:

So it's not good enough just to see a gravitational wave, you want to get the actual particle in there, is what you're saying.

Gleiser:

Yeah.

Tyson:

Next question here, sure.

Greene:

I guess I could aim my question to Dr. Greene. When does the abstract become too abstract, where you can't even possibly let's say explain to the layman? I'm a biochemistry student, I took two semesters of physics and read some stuff on the side, I thought I'd be prepared for a talk like this tonight. I am [apparently] unprepared.

Tyson:

Okay, so, Brian, why don't you take that?

Greene:

Well, I think it's vital to explain these ideas in a way that someone without technical training can understand, simply because it's so enormously exciting what's happening at the frontier and it's a shame when it's couched in language that many people aren't trained to understand. But in terms of scientific research and the progress that we make in one field or another, I don't think you judge it by how abstract it is.

You just it by how well it contributes to trying to solve unsolved problems, how well it contributes to trying to make predictions that you might be able to one day confirm. And, look, it could be that the final laws are right out there staring us in the face, frankly, and we don't have the mental capacity to understand it. So it may not be that we're coming up with ideas that are too abstract. The universe may have fundamental truths that we can't grasp. I mean, look, dogs are pretty smart, but I don't know any dogs that know the general theory of relativity.

Tyson:

Okay, that's it. Of course, Brian has the most successful books written on this subject ever. They were best-sellers, so somebody's buying them who are not scientists. And so there's some major fraction of the reading public that does receive the language, the translated language that Brian provides us. Next question, yes.

Question:

Yes, I'm one of those people whose not a scientist that reads these books, I'm a philosopher. And my question is directed to Lee, since he's grappled with philosophical issues more than anyone else I'm aware of. I was particularly enchanted by The Trouble With Physics and the earlier book, The Life of the Cosmos. Lee, how much of the problems that physicists are now dealing with and are attempting to unify all the different theories of the physical forces, how much of that is as a result of a lack of conceptual understanding of, shall we say, philosophical insight? How much of it is due to being tied to an empiricist outlook?

Tyson:

That's an interesting question.

Question:

[TALKOVER] the old Newtonian paradigm that there are things out there in the world and relations are something separate from things.

Tyson:

But just so I understand, just so I understand, is it fair to reword your question in the following way, just so I can believe I understand it? You're saying sometimes it's good to be driven by a philosophical expectation of what you would expect the universe to be and that guides your experiment and in other way is just doing an experiment without a philosophy.

Question:

Well, something like that. What I'm saying is that, maybe our conceptual apparatus is sometimes that we inherit from our day-to-day experience is simply not adequate for grasping modern physics.

Smolin:

So, I'm going to say two things that appear to contradict themselves.

Tyson:

And try to make this really in a nutshell, if you can.

Smolin:

One, okay, science progresses because there's a diversity of scientists who have a diversity of viewpoints, predilections. Some of us are very pragmatic and empirical. Some of us are conversant with the philosophical literature and the historical literature. And I think it's important for the diversity ... for science that there be diverse approaches as well as diverse styles. I also think it's the case that we're coming out of a period which was dominated by a very pragmatic tradition, which followed a period that was very philosophical-that is the physicists who dominated the early part of the 20th century were largely people conversant with the philosophical tradition. And they achieved great things, like the discovery of quantum mechanics and general relativity. And then they started to fail to achieve things and the pragmatic generation that came after them achieved great things that they failed to achieve. Epitomized by people like Richard Feynman and Freeman Dyson. And now maybe we're in a period where we face again questions where we need people who are conversant with the philosophical tradition. But the most important thing is that the only thing that matters is real results that make contact with experiments. It doesn't matter how we get there. And therefore the diversity of approaches is the most important thing for progress.

Tyson:

It's a good theme in many walks of life. Next question, here.

Question:

I'll address this to Dr. Greene on the television, because you talked about our ability to grasp. I wonder to what extent do the limits, our cognizance of the limits of logic-and this is a physics question, not a religious question-do we take that into account in our attempt to understand phenomenon? Do we ever think that they might be beyond the limits of logic, since we are, after all, embedded in the universe? And also, whatever happened to the anthropic principle?

Tyson:

Yeah.

Greene:

Well, for the first question, we theorists all work within the framework of mathematics which itself is based upon the logical structure within which the fundamental operations are constructed. So we really don't sit at our desks, encounter problems saying "maybe this is beyond logic." We say maybe this is beyond the mathematical formalism that we so far built. Maybe this is beyond the theoretical ideas we've so far developed. And we try to push them, but all within the context of traditional logic, within the context of traditional mathematics. There are some people who push the boundaries and really do fiddle with some of the logical axioms and see where that may lead, but that's really not a mainstream activity among theoretical physicists.

As far as the anthropic principle goes, well, you know, that's this idea that we really touched on with these multiverse notions that came up a little bit in the conversation. I'm surprised, frankly, didn't come up more in the conversation because this is really where string theory has gone. It's too late in the evening to go into it in great detail. But one thing that you really do have to bear in mind-when we observe the universe, our observations are biased. They're biased by the fact that we are here doing those observations. And we have to take into account that observational bias. There are things that we simply could not see because to see them we'd have to exist in a place that would be so inhospitable to our makeup that we couldn't actually be there. And that really is what the anthropic idea is about, taking that into consideration and that is something which is something that needs to be done across the board in science.

Tyson:

So, a takeaway from you, Brian, there is that before you start abandoning the very foundations of logic, there's still much more to bring us from the field of mathematics in our search for truth in the universe.

Levin:

Can I...?

Greene:

Yeah, there's no evidence that we need to abandon logic.

Tyson:

Janna?

Levin:

I was just going to say quickly that there are examples in science, particularly last century, where we did confront decided limits in physics and in mathematics, so Gödel and Turing, for instance, were the mathematicians that realized that there were facts among numbers that we will never know, that there it was an actual, fundamental limit in the context of arithmetic. There were true facts among numbers that we would never know and, not only that, but most numbers were numbers about which we would never know anything. And there was also the limit of the speed of light and maybe the limit of uncertainty in Heisenberg's understanding of quantum mechanics.

And out of each of these things came incredibly creative scientific bursts. They were not the end of understanding, but they just squeezed all of that energy into a different direction. So from the limit of the speed of limit, we discover special relativity. From Heisenberg's limit we discovered quantum mechanics. From Gödel and Turing, we delve into computer technology and artificial intelligence. So, confronting limitations isn't necessarily an end. It's often a creative kind of beginning.

Tyson:

That's a brilliant point, thanks for adding that. Yes? We'll go about another 7 minutes here? Are we okay, in the audience? A reminder that at the end of this, the panel will be out in the Hall of Northwest Coast Indians and you can bring your program, have them sign it or I think there are books there for sale, as well. So we'll take this another 7 minutes. So try to be efficient, we'll get through as many of you as possible. Go ahead.

Question:

How far do we take…

Tyson:

Oh, who is this to?

Question:

I guess Mr. Greene, but anybody ...

Tyson:

Okay, go on.

Question:

How far do we take the analogy with musical strings? They talk about...

Tyson:

We got to take that to Brian. Brian, you were on TV talking about string theory with a string quartet in the background. That seems like a stretch to me...

Question:

But in particular I was wondering what causes the vibration in these little particles and is it the Big Bang and [unintelligible] during the [eight century] created or...? And also you were talking about 10 dimensions coming-is that coming from the 10 directions that the string vibrates and how did they find those?

Greene:

Yeah, so, very briefly, I know that time is short-we didn't really say what string theory is, strangely, in this whole conversation. The idea is that the heart of matter are little, tiny, vibrating, string-like filaments and that's why we call it string theory. And as to the analogy with musical instruments, violins and cellos-this is one of the places in physics where the analogy brushes up very, very closely with the real physics. Were I to show you the equations governing the motions of the little strings in string theory and the equations governing the motion of a violin string, there are some very direct resonances between those mathematical equations. So this is a metaphor that really is, unlike many, right on target. In terms of what causes the strings to vibrate-that is, where does their energy come from?-I don't know. That basically is the question: where is the energy in the universe coming from? Why is there something, in essence, rather than nothing? We don't know the answer. We look out in the universe. We see that there is energy. If string theory is correct, a big "if," but if it's correct, then the strings would be the most fundamental, microscopic carriers of that energy and they would carry it in their vibrational patterns.

Tyson:

Okay. Brian, had I know you didn't know why strings vibrate, I mean, I don't know if I'm disappointed that you don't know this.

Greene:

Just be careful with the way you summarize what I said.

Tyson:

Okay. I'll try. Next, right here.

Question:

This is towards Dr. Gates. Curious about your theory. You say there's computer code in these equations. Now, computer code is generally just instructors for a processor and I'm curious as to what the instructions you're finding are. And, if you're not sure, what's to say that it's actually computer code? I mean, theoretically, the number pi has all the data that's ever existed.

Gates:

Well, we say that they're computer code...

Tyson:

You mean the digits in pi?

Question:

Yes.

Gates:

Okay. We say they're computer codes, first of all, because the structure of the equation is such that they dictate that there are certain things that are actually strings of ones and zero. Now, that's just digital data. But it's not just random ones and zeroes. As I mentioned earlier, let me talk about something that you probably do every day, but I don't know if you're a computer scientist or not. Most of us sit at our...

Tyson:

Sounds that kind of fluency...

Gates:

Okay, well, most of us sit at our computer screens and we type on the keyboards and we then send these, if we're using a browser, we're sending strings of ones and zeroes elsewhere. But on the other hand, in the transmission process, there's always some fluctuation. So a zero that you type here because of static on the line might be rated a 1 at the other end and vice-versa. And so in fact, when you sit and type on the keyboard, your computer's doing something behind your back. Namely, it throws in a bunch of extra ones and zeroes, and these things are called error-correcting codes, so that the computer at the other end can look at the whole collection of what you typed plus what was sent and figure out if there were bits that were being flipped back and forth. And that's how you get accurate transmission of digital data. Among the codes that are used for this purpose are a special class of codes that are called block linear self-dual error-correcting codes. They were first-in fact, the Shannon extended checksum code is an example of one of these things-these are the codes that we find buried in the equations. Not just any code, but these self-dual error-correcting block codes. It's quite remarkable for anyone that I've talked to. We have no idea what these things are doing there.

Question:

Any literature out?

Gates:

I'm sorry?

Question:

Do you have any literature out that ...?

Gates:

I can give you technical references that almost nobody in the world can understand.

Tyson:

But I thought you had a popular-level article on this?

Gates:

Thank you, yes, actually, so this past June the British journal Physics World asked me to write a popular-level description of what we have found. So in the June edition of Physics World-and it's published in London-the cover story is called "Symbols of Power." It's about these weird symbols that have been showing behind us-we call these things adinkras. And so, for a popular level description, yes, we've written that. But other than this one popular-level description, it's all technical gobbledy-gook. And that's a technical term, by the way.

Tyson:

Gobbledy-gook. Thank you. Okay, I'm sorry, we're only have time for two more questions, I've just been cued. But you'll be one of them, so come on up to the microphone, sure.

Question:

Okay, yeah, hopefully this isn't overly stupid question or uninformed, but I'm just curious whether...

Tyson:

I bet it's not. I'm gonna bet you.

Question:

Thank you, but I'm wondering whether the quantum fluctuations, like random particles, like popping into existence and out of existence, whether that could possibly be explained by particles moving through other dimensions into, say, a plane that we exist in and, if that's impossible, can you explain why?

Tyson:

Not only was that a good question, you're making everyone else in this room feel stupid. I just want you to know, okay? Just so you know. All right. Who wants to volunteer for that one? Katie, you want to hit that. Virtual particles coming in and out, is that another dimension talking to us?

Freese:

Well, we definitely know that particles pop in and out of existence. It happens everywhere all the time and this gets back to the-this is what people think might be responsible for the dark energy. Only the problem is, when you do the calculation, it comes out wrong by 10 to the 120th power, 120 in the exponent. So in fact there's much too much of this fluctuation going on in our calculations. So if you're going to include the amount in the other dimensions, it's not going to help. So I don't think that's a very good answer to your question, but you strike-this is at the heart of one of the deepest problems in all of physics. So, not a stupid question.

Tyson:

Marcello, you...?

Gleiser:

I just wanted to add that, yes, theories with extra dimensions, when there are certain properties of these extra dimensions that they oscillate in certain ways, they can produce particles in four dimensions that we can actually detect called pyrgons, I think? Sort of an old idea.

Tyson:

Gurdons?

Gleiser:

P-Y-R-G-O-N-S, right?

Tyson:

Pyrgons?

Gleiser:

Pyrgons.

Tyson:

Gons. Sounds like creatures out of Star Trek or something.

Gleiser:

So, yes, the presence of extra dimensions create certain particles in four dimensions, or could create. I don't know if they're electrons, but they could be there.

Tyson:

Okay. I think we have the last question here. Welcome.

Question:

This is, again, touching on mathematics and the question is: to what extent are our systems of mathematics and measurements subjective or objective, invented or discovered. Gödel of course talks about incomplete systems, but Einstein says as far as the laws of mathematics refer to reality they are not certain and as far as they are certain they do not refer to reality. Any comments?

Tyson:

Yeah, Janna, why don't you take that? This is what you've been working on.

Levin:

Uh-huh.

Tyson:

Which gives you the final comments [TALKOVER].

Levin:

Still working on it. The interesting thing about Gödel is that he really was a strict Platonist. He actually believed that mathematical forms had concrete, objective existence. This world he wasn't so sure about. He wasn't really sure if his ordinary experience was created by his own mind and he really had breaks with reality, but he did believe in transmigration of the soul and the idea that he would get closer and closer to a platonic reality where it would all be perfect circles, pi, you know, irrational numbers. I think it's hard for most of us to follow that particular philosophy. I think that there is no simple answer to whether or not mathematics is the objective reality. I mean, Lee sort of brought up this idea that maybe it's just a description but one which isn't-could never completely encapsulate-did you say that or am I projecting?

Smolin:

Yeah.

Levin:

Could never completely encapsulate physical reality. I mean, I think it's difficult to make a philosophical determination. I believe in being a bad philosopher and at times being a complete objective realist in terms of mathematics when it's convenient and times not being. But what seems to be true is that functionally it's incredibly powerful. Functionally, it continues to work. And so we continue to pursue the ramifications of mathematizing the universe.

Tyson:

I want to live in a world with irrational numbers and rational people. Let's end with us a, in 10 years, where is string theory going to be? Or TOEs? 2021, where is it going to be? We're going to come right on down and we'll end the evening. Go.

Smolin:

I hope we have a quantum theory of gravity, whether it's string theory or not and I hope that there is experimental test of it and verification of it. I think it could be one of several approaches. Maybe loop quantum gravity, maybe causal dynamical triangulations and maybe string theory. And we shall see. This is science which means we don't know the answers.

Tyson:

Will we see it in 10 years?

Smolin:

Yes.

Tyson:

Good. How about you?

Levin:

I think...

Tyson:

2021.

Levin:

I think it's a great time to be a scientist. We have great experiments on the horizon. We're going to see space ringing [in] gravitational waves, we have the Large Hadron Collider, and we have great mysteries. We know there are things we don't know. There's dark matter, dark energy. We know we haven't unified all the forces. So we have great mysteries, we have tools to approach those answers. I'm pretty optimistic that some of the pieces of the puzzle are going to fit together.

Tyson:

So the known unknowns are quite striking.

Levin:

Yeah.

Tyson:

Are any unknown unknowns out there? You wouldn't know.

Levin:

You're confusing me.

Tyson:

Marcello, 10 years from now.

Gleiser:

So, yes, I think that at least in 10 years we'll have excellent data to possibly either confirm or rule out supersymmetry and also know if the Higgs particle, which we also did not mention tonight, exists or not.

Tyson:

That's the famous God particle, giving mass to all the other particles, right?

Gleiser:

Right. Actually used to be called the goddamn particle, because they...That's what Leo Lederman, who wrote this book, The God Particle said. His real title was The Goddamn Particle, but the editor didn't like it.

Tyson:

The editor changed it, yeah. So, anyway, so I'm optimistic in the sense that we'll have the data. I am very skeptical with notions that our ideas, when they go too far, have something to do, always have something to do with nature. This sort of extreme Platonism worries me a lot.

Tyson:

All right, Jim, 10 years, where are we?

Gates:

Well, first of all, Marcello just actually took my answers. I think in 10 years...

Tyson:

Okay, so we skip you.

Gates:

Yes. That works.

Tyson:

No, seriously.

Gates:

Oh, you're not serious? Oh. I think that-well, in my pessimistic moments I think that in 10 years string theory is not going to be complete, because what's going to have to happen is a genius is going to have to appear and that doesn't occur on anybody's time clock. We actually are going to need...

Tyson:

So you're agreeing that the whole community's just not smart enough to figure it out.

Gates:

No, because such people do appear.

Tyson:

No, no, but right now all the people who have been working on it aren't smart enough, that's what you're saying.

Gates:

No, because, given time, one of them might actually be that genius.

Tyson:

Okay.

Gates:

So in my darker moments I think in 10 years we are not going to have what Lee will probably be happy to hear, which is a background independent description of string theory. I think that's the absolute, most important thing to find.

Tyson:

Okay. Katie. Ten years, 2021.

Freese:

Dark matter, yes. Dark energy? Mmm, we'll know a little bit more. Higgs, yeah, probably.

Tyson:

Again, the particle that gives mass to all other particles.

Freese:

The goddamn particle.

Tyson:

The goddamn particle.

Freese:

Gravitational waves-good bet. So a lot of the data are going to come roaring in. But is this going to prove or disprove string theory? Probably not.

Tyson:

Okay. Just give us a better understanding of the 4% plus the dark matter, not the dark energy.

Freese:

And the supersymmetry, which is an important ingredient. And possibly the things Lee was talking about, these tensor modes that tell you perhaps about something coming from the string epoch. So there's some hints there.

Tyson:

Brian, we're giving you the last word here, 'cause you had the first word. You're going to close this out. Ten years from now, 2021, where are you?

Greene:

Well, look, here's my feeling. I really enjoy these Asimov debates and to secure my place at the 20th anniversary Asimov debate, I'm going to hold back my answer until then.

Tyson:

Join me in thanking the marvelous panel. 2011 Asimov panelists, thank you one and all. Thank you all for coming. We'll see you again in a year and we might see you just out in the Hall of Northwest Coast Indians. It's been a great evening. I learned quite a bit. And we will have the panelists there. I also wanted to just thank a few people. There's Suzanne Morris who ran this whole thing, made it run as smoothly as these always do. And my assistant-yeah, thank you, Suzanne Morris. My assistant Elizabeth Stachow. And we have a whole slew of volunteers. Collectively, I just want to thank them all for making these evenings run as smoothly as they do. We'll see you again next year and we might see you again out on the tables.

[End of audio]