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Birnbaum v.

Brian Greene

Living in three dimensions can be hard enough, but 10? More than 10? Our man in Boston engages physicist and author Brian Greene in a fascinating conversation about string theory, science writing, and the type of nightmares that haunt contemporary physicists.

For those of you breathing a sigh of relief at recent news that the Universe will exist into the inconceivable future before it implodes, one might caution that this estimate—‘the data support the idea that the cosmos will continue expanding very slowly outward for at least the next 30 billion years’—is somewhat tentative. ‘The simplest assumption is that the universe will become ever darker, and ever emptier, as the galaxies recede from us and in the very far future, there will be nothing in evidence. Everything will have disappeared beyond the horizon.’

Enter Brian Greene, widely considered one of the finest scientist-writers of his generation and often compared to Albert Einstein and Stephen Hawking as well as Carl Sagan.

Cosmologist/physicist Brian Greene has degrees from Harvard and Oxford and currently teaches at Columbia University where he is a professor of physics and mathematics and co-director of the Institute for Strings, Cosmology and Astroparticle Physics. For more than a decade he has been working on unified theories and quantum mechanics and in the course of that work has refuted Albert Einstein’s theory that space can stretch but not tear. Greene has lectured both technically and generally in over 25 countries and is recognized for a number of groundbreaking discoveries in superstring theory (the theory that’s discussed and explained in the conversation that follows). He has written The Elegant Universe, which received a number of awards and was a Pulitzer Prize finalist in 1999 and was also the basis for a recent NOVA three-part series hosted by Greene, and The Fabric of the Cosmos: Space, Time, and the Texture of Reality, his newly published book.

As you will see from what follows, Brian Greene is passionate about his beliefs. As he exclaims below, science is ‘something that is really weird and wonderful and cognitively very expansive… science also touches the heart. It also is a visceral, internal experience,’ and, ‘When you learn these different features of the universe, it changes your perspective on what it means to be alive. What it means to be part of the universe, since the whole notion of universe is so beyond what experience would lead you to believe.’

Good thing we have another 30 billion years to consider it.


Robert Birnbaum: It’s probably best to start at the beginning. What’s the basis for the calculation that the universe was created 14 billion years ago?

Brian Greene: Basically, when we look out into space we see all galaxies rushing away from us. And the interpretation of that is that space is stretching. And, in a sense, the galaxies are attached to space. So as space stretches the galaxies are drawn apart and that is why everything is rushing away.

RB: It’s rushing away because you have a concept of duration?

BG: We have a concept of time and of things being closer to us at one moment and a little further away a moment later and so forth. Now if you run that picture in reverse, everything that is rushing apart comes back together. And based on your understanding of how quickly things are rushing apart, when you run the film in reverse you can count how long it would have been in the past that they must have started essentially all on top of each other. And that’s what we consider the beginning. You do that calculation; it comes out to about 13 billion years or so.

RB: About?

BG: Yeah.

RB: Not 14?

BG: Thirteen and change. It’s like 13.7 billion or something.

RB: In the beginning of The Fabric of the Cosmos, you describe musing in your father’s library as a youth and, among all of the large and leather-bound tomes you looked over, you came across a slender volume by Albert Camus, the Algerian-born Nobel laureate (not French).

BG: Right.

RB: You were fascinated by [his essay] The Myth of Sisyphus and the issue of suicide and the notion that we needed to understand the value of life. I am at a loss to understand what I thought was a leap of reasoning. Why would any calculations that you make about the physical universe have anything to do with values? However you determine the constituents of the universe, whatever proofs you give me—you know where I am going—

BG: I do. I don’t think that science changes values per se, by any means. So that isn’t an argument that I’d want to make. An argument that I would make is that an understanding of science and physics, in particular, places everyday experience in a completely different, unfamiliar, very, very rich context. When you learn that there may be more than three dimensions in space. When you learn that time is not what your intuition leads you to believe. That different people moving in different ways are experiencing different gravity fields, that time elapses at a different rate—when you learn these different features of the universe, it changes your perspective on what it means to be alive. What it means to be part of the universe, since the whole notion of universe is so beyond what experience would lead you to believe. And that’s the sense in which I find that this kind of knowledge has an impact on what it is that you do.

RB: This sounds more like a commonsensical observation than what I thought you were arguing in the first chapter.

BG: I make it clear in the book. I don’t mean to talk philosophy at all. There is a parenthetical remark where, as a joke more than anything else, I say I won’t be talking about philosophy or suicide. The point I am trying to make there is that science is usually portrayed in the media, in popularization, as something that tickles the mind. Something that is really weird and wonderful and cognitively very expansive. All that’s true, but what that misses is that science also touches the heart. It also is a visceral, internal experience that really—

RB: Many people don’t seem to see it that way. Is it a function of marketing or a cultural taboo or something else that it isn’t seen the way you describe?

BG: That’s a big part of it. Certainly when science is taught in schools, it’s taught as a very cut and dried subject.

Do you explain what you think about to your mother? I tried and I can get just so far and it’s not that she doesn’t have the ability to get this—everybody does. It’s that she doesn’t feel compelled to understand it. She is a much more practical person. She likes real estate.

RB: That seems to be the case for many things taught in schools.

BG: It depends on the teacher. I certainly had some teachers who taught English or taught history in a way that really felt more than just a textbook subject. Science was very much a set of rules. You learn the rules, try to solve some problems. And to me that is not what science is. It’s a component of science. Science is life. It’s not separate—

RB: Everyone wants to argue the primacy of their subject or discipline.

BG: Probably. [laughs]

RB: Which doesn’t make the claim illegitimate.

BG: That’s right. That’s why people choose a discipline, because to them it really does touch the—

RB: What we are really fighting continuously—especially in public education—is a strain of anti-intellectualism. That ultimately makes the approach to education a matter of making the subjects cut and dried.

BG: Right. There is an op-ed piece in the Times where it was discussing science education—Nicholas Kristof wrote it—and he was describing that we are 19th on the list in science education—you know these kind of statistics we are familiar with—

RB: Trotting out these figures is a regular media sport.

BG: I basically agree with what he was saying. But what needs to be pushed much more strongly is, it’s not just a matter of making the education system better in the traditional sense so that people score higher on tests. It’s really a matter of making it better so that students understand why this stuff matters and they get fired up about it and enthusiastic about it. That’s how students start to learn more. When they want to learn. That can be done.

RB: Can it be done when teachers spend a fair amount of their time trying stay afloat financially?

BG: What I mean [when I say] that it can be done is, I know that the material can grab you at a deep level. How to implement that, I have no idea.

RB: I have talked to writers whose specialty or forte is fiction that is grounded in some aspect of science, Karl Iagnemma, a young robotics engineer at MIT who’s written a story collection. There’s Andrea Barrett, who has written stories and novels based on scientific explorations and various areas of biology. There is a way in which they are called upon to defend their seemingly unlikely subject matter as if it were odd and foreign material. Why does it seem as if there is a bias against science in pop culture?

BG: It’s interesting that you phrase it that way. I have, in the last few years, experienced the complete opposite. I have gotten so much email from artists, from writers, from composers, who are looking to science as the next place for inspiration. So many of them want modern physics to be the place that will be the wellspring for the next creative undertaking that they are doing. So, the bias that you refer to, I don’t sense that it’s really there—at least now.

RB: Your email sampling is—

BG: Very self-selective.

RB: Right.

BG: I agree. It could be misleading. I do get the sense that there is a growing interest in integrating science into artistic undertakings. There is a fellow in Santa Barbara who is organizing a three-day conference that’s all about playwrights, writers, and scientists getting together. And the Sloan Foundation in New York is sponsoring a theater company, the Ensemble Studio Theater, and they are giving awards for people who are writing plays with a scientific theme and they are putting them on, on a regular basis. They are also sponsoring screenwriter competitions—so that there will be more films, which are based on some scientific ideas. The trend, I really think, is going toward integrating science into these pop-culture things.

Credit: Robert Birnbaum

RB: I had recently talked to an engineer, or at least he was trained as an engineer, whose main preoccupation is writing about things like pencils and paper clips and bookshelves and bridges. In his latest book he deliberated on the impossibility of perfection in the matter of humans designing things for humans to use. The point here is that that of what he is doing is addressing the view that people have that engineering is a dry, boring, and mechanical discipline. Is it a function of having to wait for someone to overcome a conventional bias by making these various subjects accessible to people?

BG: It must be to some extent. I have a similar prejudice when it comes to certain fields. I won’t name them. Some of them, it is hard for me to see why they are particularly interesting. Yet there are people who find them thoroughly fascinating. Maybe it does require somebody to translate the esoteric impression you get of a field to the compelling nature of the subject matter that got them hooked in the first place.

RB: You mentioned that one of things that physics does and is doing is giving people the signal to go out and look at the world and instead of seeing what you are predisposed to see, you will see something different—you may not see the entities that physics deals with but—that’s an age-old dilemma isn’t it? Like the fable of the three blind men and the elephant. Everybody touches a piece of reality and claims that’s the thing.

BG: The one difference relative to that particular story is—that story always struck me as showing how different perspectives that seem disjointed and disconnected can have a hidden unity between them, so long as a you have an overarching seer who puts it all together.

RB: Somebody, some storyteller has to say it’s an elephant and that the men are touching parts of it—

BG: Exactly. So the person who sees the elephant puts all the pieces together. What I am referring to is related to that but in a sense it’s deeper. What physics is really revealing to us is that everything that you see is this glossy exterior to an underlying reality that physics is revealing, that is very surprising and very rich. Very elegant and very beautiful. And that underlying reality, we can see it once in the equations, it’s not as though we only have one piece or another. Certainly our understanding is not complete but as we go deeper and deeper we do see that everything that we are aware of through common perception is not truly how the world is put together.

RB: What was that game you played with your father?

BG: When I was a kid, my dad and I would walk down the street and the game was to look at some event that you might see—some of the examples I give in the book, some simple ones: somebody drops a coin, or an ant walking along some surface of some sort—and not describing the event from your point of view but describing the event from some arbitrary but definite point of view that is completely different from your own. From the point of view of the ant or the point of view of the falling coin, and so forth. And the challenge of the game was when one or the other of us would give this description of the world from this unspecified perspective to go from the description to whose perspective it was that things looked that way. If you are walking along some brown cylindrical object and you have these textured walls and there is this white stuff coming from the sky—that would be the point of view of an ant walking on an hot dog and you have a street vendor putting sauerkraut on it. It’s a very interesting game in the sense of it allowed you to see different perspectives, forced you constantly to look at things from a very different point of view.

RB: For me, that summons forth the notion of empathy. That in human interaction it is of great value to see people’s behavior and responses through their own eyes.

BG: That’s right. That’s a touch deeper than the game we were playing when I was little. That game is a first step toward being able to do that because you are constantly going outside your own head.

RB: Why is the most common layman’s description, maybe I even saw it in your book’s press materials, ‘head numbing,’ ‘headache producing’? Is this string theory information too much for people to process? Because we are not used to it?

BG: We are not used to it. What you are asked to do by modern physics is to, in a sense, mistrust everything that you experience. That’s hard to do, especially if you haven’t done it before. Because what you see seems to be what there is. Reality seems to be revealed by our sense of sight, our sense of touch, our sense of sound. To recognize that it isn’t really true is pretty tough and it’s not something everybody wants to do. For example, my mother cannot understand why anybody would spend their life doing this kind of thing. And that’s fine with me and there—

RB:—[affects the voice of the disappointed mother] ‘Brian, you should have been a doctor.’

BG: ‘Why aren’t you a doctor or a lawyer?’ I understand. [laughs] It makes some sense from a certain perspective. To me the world just becomes much more wondrous when I see everyday stuff as part of a much bigger story.

RB: Do you explain what you think about to your mother?

BG: I tried and I can get just so far and it’s not that she doesn’t have the ability to get this—everybody does. It’s that she doesn’t feel compelled to understand it. She is a much more practical person. She likes real estate.

RB: [laughs uproariously]

BG: She is very concrete, [laughs] which is great. To me, I just gravitate toward—and I think many people do—let’s look at popular culture again. The Matrix, a very successful movie. Why? Well, it was a great movie (Matrix one, I am referring to) but at its heart it had the notion that what you see is not really what there is. That touches people, because everybody or many people are searching for a deeper reality and anything that kind of brushes up against a deeper reality.

Credit: Robert Birnbaum

RB: I find that impulse a little frightening—its outcome is frequently religious dogma.

BG: It can be for some people but for many people it’s not. Ultimately the deeper levels of reality that are subject to experimental testing, those are the ones that grab me. That’s not the right measure for the religious sensibility. My brother is a Hare Krishna and his deeper reality differs from mine. He finds it very fulfilling, what he does. It’s not his full-time occupation, but it is the grander picture for him. Now, that’s not an experimentally testable framework, I don’t think. And I don’t think that’s the right measure. For him, it’s a more spiritual measure. For me it’s, ‘Does it work? Can you test it in the lab? Can you test it through astronomical observations?’ I don’t think one is better than the other. Certainly one grabs me more than the other. But that’s a personal choice.

RB: Early on you talk about some of the theoretical explanations being discarded or rejected because theorists couldn’t come up with the math. What does that mean?

BG: Many times in doing physics research you will have a vague idea of how something should work. But we don’t consider that vague idea to be a real contribution until it is reframed in mathematical language such that it makes empirically testable predictions, and it is not that the initial idea might not one day be translated and therefore the contribution of the idea is important, but it is hard to assess anything in this framework.

RB: Would a corollary be having a pre-linguistic experience?

BG: Could be. Einstein, or so he said, thought in pictures. And only later put the pictures to mathematics—and sometimes he had help. And that is not an uncommon way of discovering things in this field. Have a picture, have an intuition, have an idea, and then try to flesh it out. But the only way that it can be assessed by other members of the community is, ultimately, when it is framed mathematically.

RB: You are both a mathematician and a physicist?

BG: The work I do is on the mathematical side of the field. But again, I stress over and over again, that to understand the ideas you don’t need the math. That’s the point of a book like this, to have the math, as the underpinning, but hidden from view—hidden in the notes so the ideas are clear.

RB: The book is something of a primer—you discuss the history of modern and contemporary physics from Newton and Leibniz and Einstein all the way to you. Today the reigning theory is superstring theory?

BG: Right.

RB: Is there a difference between string and superstring theory?

BG: There is no real fundamental difference. The ‘super’ in superstring refers to something called supersymmetry, which is a certain property of a certain class of theories. But at the end of the day we use the words fairly interchangeably.

RB: Alan Lightman, who is now a novelist—

BG: He was a teacher of mine when I was an undergraduate at Harvard.

RB: As a physicist.

BG: Yeah, back then.

We believe string theory is what in essence [Einstein] was looking for. This unified theory, which does put general relativity and quantum mechanics into a harmonious merger, demands that the world have these extra dimensions. So it’s an indirect impact on our life, these extra dimensions, but nevertheless a deep one if the theory is correct. It’s the explanation for why things are the way they are.

RB: We have talked recently about the notion that physicists don’t get better with age.

BG: Uh, sure.

RB: Maybe Einstein was an exception. Maybe he didn’t get better.

BG: Some people would say that he didn’t.

RB: So there is grinding along a notion that there is an age at which you are at your peak, much like an athlete. In Alan’s case he decided to devote himself to writing and he is confident that writers get better with age.

BG: [laughs]

RB: Is there an endgame for you in physics? Do you think about the scope of your own inquiry and the issues and problems—is there a limit?

BG: From the physics point of view? I know that many people feel this way about physicists reaching a peak early on and not really doing anything afterward. I remember Alan Lightman wrote a very poignant article in the New York Times’s ‘About Men’ section in the 1980s, actually when he was my professor at Harvard. That’s why I remember reading it. My feeling at the moment is that it’s not that physicists dry up. It’s that they don’t move around enough in their field and so they stay on one thing. You tend to think about it the same way and it’s like the game with my dad, you don’t have the other perspectives coming in and that’s where things get tired. I don’t think the brain—yes, I know, I hear we lose a lot of brain cells and so forth—I don’t think the brain really dries up. It’s just the new way of looking at things. I have been trying to shift what I work on frequently enough that I don’t feel like I am drying up. I don’t feel that I am. For many years I was working on the mathematical side of string theory, the extra dimensions and so forth. The last couple of years I have shifted to cosmology. It’s actually mirrored in this book. I am trying to see whether string theory might yield observational tests that we might one day look through telescopes and we might see evidence of string theory through cosmological observations. So I think it’s really a matter of shifting what you work on and in that way I think you can keep on producing for as long as you are around.

RB: It was interesting to see the notes on you as referring to you as mediagenic. What does that mean? That you are good on television and that you can answer the dumbest questions that someone can throw at you?

BG: Right, that’s probably part of it.

RB: Here’s the thing: You are out there, which must be refreshing after sitting in a lonely laboratory. How do you do what you do? Do you walk around thinking of issues of physics? Or sit in one place?

BG: It’s a combination of both. Certainly when I am in the middle of a calculation or am stuck on a problem, it’s always with me. I am walking around thinking about it—it’s in the back of my mind, kicking around ideas. Have a thought, sit down on a stoop somewhere, work out a little equation, and it may shed light on that thought whether it was valuable or not. So it is kind of a 24-hour-a-day thing. Which is both good and bad. There are times I will be like, ‘Oh, I want to get this out of my head. I want to stop thinking about it.’ It’s this kind of obsessive quality when you are trying to solve a physics problem. But I guess, maybe in the end that’s what it takes to make progress. I don’t know. Many people work in many different ways.

RB: So now you are out here in public talking about your second book. What are you asked in the one minute or three minutes allotted? What is string theory?

BG: Often it’s a question of that sort. It varies tremendously. What I find is in particular, in writing the book, not so much in interviews—I found both in The Elegant Universe and this book, it refocused the way I thought about things. So it wasn’t just an effort that took me away from the science that I wanted to be doing. When I was writing The Elegant Universe, it really focused my attention on cosmology. As I was writing it every question seemed to me ultimately ending up with, How do things really begin? What was the big bang and so forth? And that was not the focus of that book, but I started to work on that much more after finishing the book, from the point of physics research. And then this next book reflects this shift in direction.

RB: What is more difficult? Contemplating these deep issues of physics or writing about them?

BG: Of course they are completely different. It’s difficult to compare. When I am sitting down to do the physics—this could just be attitude—I always have a feeling like the answer is out there. And what I have to do is somehow get to it. This image of the sculptor chipping away, the sculpting masterpiece is inside and it’s just about removing the external marble to reveal it. So I always feel like I am seeking something that is there. When it comes to writing, I don’t feel that way. I feel that it’s got to come from inside. The answer is not out there. The answer is, ‘How am I going to explain this? How am I going to put this together? How am I going to make this interesting and what language am I going to use?’ So it feels like I am really generating the book from an internal place. Whereas the physics feels like I am trying to reveal what’s already out there.

RB: You would say they are both creative enterprises?

BG: Yes. Totally, but of very different characters. I find it very easy, if I have a spare hour, to sit down and do a little more writing if I am in the middle of a book. I find it very hard to sit down if I have a spare time and do physics. I need four hours—there is more of a gear-up time, there is more of a fiddling time. So again, even the process for me is very different.

RB: The time units are different.

BG: Yeah, yeah.

RB: As point of personal distinction you will end up occupying a select company; there aren’t that many people—the model that is mentioned is Carl Sagan—who crash into mainstream popular culture as a guru of contemporary physics. What is the spillover when you are trying to hash something out that extends your theoretical work and somewhere in you, you have to be aware that it will be incumbent on you to explain it to a lay audience. I am just trying to understand people of multiple talents—are your investigations affected by the knowledge that you will be translating them to a broader audience?

BG: When I am doing the science research, I have no idea what I am ever going to explain about that particular piece of research, whether it’s going to lead anywhere, whether it’s interesting enough, solid enough to really get out there. That process is really unto itself. Certainly when it gets to a writing stage, I decide to write a book, then I reflect back on all that stuff and reflect back on the entire field, the history of hundreds of years of science to try find a narrative that really tells the story.

If things occur in our world simply as a matter of historical happenstance as opposed to fundamental law, then the whole enterprise would be cast in a very different light. And I don’t like that light.

RB: Is the first draft of your research in a language people can understand?

BG: Totally not, totally not. [chuckles] It’s always equations, it’s always equations that are scribbled and crossed out and put back together. Ultimately if it pans out into something interesting, what I need to do—maybe this is related to what you are asking—for me to feel like I have really understood what I am doing or what I am learning, even if it’s someone else’s work, I need to turn that math into a mental picture. Otherwise I feel like I don’t know what I am doing. And that mental picture would be the kind of thing that I turn into a book like The Fabric of the Cosmos.

RB: String theory says that there are 10 spatial dimensions and one temporal dimension? What is a dimension?

BG: Good. It’s an idea that some people have a little bit of trouble with. Dimension is an independent direction, if you will, that you can move. In everyday life you have left-right, that’s one dimension. You’ve got back-forth, that’s a second dimension, and up-down, that’s a third dimension. They might say, ‘What about at an angle?’ That’s actually a combination of these put together, so we don’t consider that to be a new dimension.

RB: Like primary colors combine to form all the other colors.

BG: That’s exactly right. You put the primary colors together, you get anything you want. You choose motion in any of these three axes and you can get any motion in the three dimensions that we know about. These theories really do say there are other independent dimensions in addition to left-right, back-forth, up-down. You can’t see them and that is what makes it so hard to take the concept onboard.

RB: [laughs]

BG: But the theory claims that they’re there. One explanation we have is they are there, but rather than being straight the way left-right, back-forth, and up-down are, they are curved. And they are curled up and they are curled up very, very tiny. That’s why we don’t see them with the naked eye. Were we an ultramicroscopic ant walking around, we would have other options for direction to move beyond the ones we know about.

RB: What does that mean for us in real life? How do these additional dimensions explain any of my experiences?

BG: It depends on what one means by one’s life. If you mean how is it that you exist physically? Well, our current theories, general relativity on the one hand, which is a theory about gravity, why the earth exists and the sun exists, and our other theory, quantum mechanics, why atoms can exist, the atoms that make up the molecules that make up you, why they can exist? These two theories, it turns out, are mutually incompatible. So the explanation for gravity and atoms and molecules doesn’t fit together. That is a big problem! String theory is the first theory to come along and show—

RB: What about Einstein’s unified theory?

BG: He sought a unified theory and he never found it. We believe string theory is what in essence he was looking for. This unified theory, which does put general relativity and quantum mechanics into a harmonious merger, demands that the world have these extra dimensions. So it’s an indirect impact on our life, these extra dimensions, but nevertheless a deep one if the theory is correct. It’s the explanation for why things are the way they are.

RB: Is the appellation ‘the theory of everything’ a comic one? A sarcastic one?

BG: I hate that phrase, the theory of everything. It gives a sense—an incorrect sense of things. What we really mean is it is a theory of the basic ingredients and the basic forces. But how those ingredients and forces build up complicated things like a human being or a human brain or consciousness… We have a principle—the brain is made up of molecules, atoms, strings interacting in the manner dictated by this theory. But we don’t know how to bridge the gap between something so complex as the brain and something as minute and fundamental as a string. So it’s a phrase that is alienating. Other scientists, if this is the theory of everything, then what are they doing? Nothing? It’s crazy.

RB: Whose phrase is it?

BG: It came around in the 1980s. I think. And it’s unfortunate. If it is taken in the right way, it’s a nice phrase. But without qualification—unified theory is a much better phrase.

Credit: Robert Birnbaum

RB: What is a contemporary physicist’s nightmare? What would be a scary thing to you?

BG: It would be to learn either—there is no fundamental way to understand the basic laws of the universe. If someone were to come up with a theorem—and there are such theorems in mathematics, Gödel’s theorem, which basically shows there are propositions in mathematics that you will never be able to prove true of false. They are undecidable. And that from the point of view of mathematics is an esoteric, interesting idea that has various applications. But were one to prove such a thing for physics—you’ll never be able to understand why that star is doing what it does—fundamentally, that is a nightmare. The second nightmare, I think, although some people have tried to spin this a different way these days: What if our universe is one of many, many universes and all the other universes are very different? They have different particles and forces and properties and so on, and then the question of why the universe that we know about has the properties that it does all of a sudden seems like a fool’s errand. Because there is nothing fundamental about the way things are here, because things are different and can be different in the other universes, and maybe just chance is why things are the way they are. So if things occur in our world simply as a matter of historical happenstance as opposed to fundamental law, then the whole enterprise would be cast in a very different light. And I don’t like that light. [both laugh]

RB: You live with the fundamental belief that it is all explainable?

BG: I do. It is the underlying assumption in everything that I do. If that were proven—

RB: How’s it going? [both laugh] Doing OK so far?

BG: Pretty well. I think that is an amazing thing. There is essentially no problem so far that when we have put our mind to it where we haven’t been able to make progress. We have made progress on every problem that we have a sought an answer to.

RB: The idea of scientists and artists talking and exchanging ideas seems like a good idea; what could be bad about it? But is there an expectation that something predictive should follow, ‘Are we going to be on Mars anytime soon?’ Or, ‘Are computers going to be able to this and that?’ Is that anything that is interesting to you?

BG: It thoroughly is. But the work that we do is not the right work to make such predictions. Because it’s too low down, it’s too fundamental.

RB: Right. But when you talk to writers and sculptors and playwrights and musicians, does it come up?

BG: Surprisingly, it’s rare that in those conversations somebody is really pressing for some real-world, everyday implication or real-world prediction of how things will be in 10 or 50 years from now. More people are really asking questions such as, is it explainable? Is the universe fundamentally explainable? If so, how different will that explanation be from what I would have thought, if I lived in the time of Newton, where again, the universe was assumed to be that which you see at some level? And I think that’s more where people are coming from when this material is trying to drive a novel or screenplay or a play. For instance, there was a play in New York called String Fever. And it was interesting and the main character was played by this woman Cynthia Nixon and it was about a woman whose life is falling apart but she uses physics and string theory, in particular, as an anchor in her life that she keeps coming back to, in terms of, everything in her world might be crazy but at least her fundamental understanding is stable and solid. That captures well how a lot of people look at science. This kind of fundamental science.

RB: That reminds me that in the early ‘90s Martin Amis wrote a novel called Time’s Arrow, about a concentration camp doctor whose life is told backward. And now there is a novel by Andrew Sean Greer, The Confessions of Max Tivoli, in which the 70-year-old protagonist also lives life backward, or at least the story is told that way.

BG: Is this the guy who gets younger and younger?

RB: Yes, it was reviewed in the Times last Sunday. These are the kind of stories that seem to be influenced by issues in physics—especially the matter of understanding time.

BG: Yeah, I think time is the most puzzling of all. The reason is we are given so little of it. [both laugh] We are always trying to [somehow] save it or understand it better or be more efficient with it and it is so perplexing why it is that time seems to relentlessly march forward. Where [sort of] as in space, which Einstein taught us was related to time, [somehow] you can go left or right or back—you are completely free—your motion in space. [But] why is your motion through time not free as well? It’s very hard to answer that question for fundamental physics. Chapters in the book lay out the puzzles, and the main puzzle is that when you look at the laws of physics they seem to show no distinction between what we call forward in time and what they call back in time. Future and past are on equal footing from the point of the underlying equations. So why are they on such different footing from the point of view of everyday experience? And in struggling to answer that question—many people have dealt with this—the most compelling answer is that the big bang itself imprinted a direction to time, imprinted an arrow, it set time flowing in one direction so to speak, using metaphorical language which can sometimes get you into trouble. Ultimately it comes down to cosmology. And that’s why the book has a lot of cosmology. It’s ultimately trying to address this question, Why is the future different from the past? Why does time seem to have direction printing only towards the future, thus making the past somehow inaccessible?

RB: Here’s David Denby quoting Heidegger in his memoir American Sucker, ‘We are all of us ‘running ahead’ to our past. That is, we have only the future, which approaches and then passes us by—it becomes the present, and instantly (indeed continuously) the past, falling somewhere behind us.’

BG: Good. So that is the intuitive notion of time, and what Einstein taught is that picture, that quote, is just darn wrong. He taught us through relativity, what you might consider your past might be my future depending upon on how far apart we are in space and how we are moving relative to one another. I had an op-ed piece in the New York Times where I tried to lay this out and The Fabric of the Cosmos does it in more detail, where if you are billions of light years away from me and you move relative to me what you consider the moment, one moment in time for me will actually include events—I consider to be—in the future and in the past. So this notion that there is this universal conception as in that quote, that the future is out there and kind of hits us, becomes the present and immediately becomes the past, that’s a completely subjective experience of time. And the more objective view would see all the moments arrayed in a giant temporal landscape and they’d all be out there. So it’s not that the past is gone and the future is yet to be; they are all kind of there and it’s human experience that illuminates certain moments to be the now. But that’s a subjective experience.

RB: I have often thought about the imminence of time.

BG: Do you have that feeling? I don’t.

RB: I have thoughts about it. I can’t be sure that I have felt it.

BG: I try to force myself to think that way.

RB: I see it, as being in larger moment, not anchored to something narrow and specific.

BG: If you can do that I am jealous. [laughs] But I believe that’s the right picture.

RB: Is it the case, that there is the same attitude about science and basic research as when the Soviets panicked the so-called free world with the launch of Sputnik? Do people make money from physics research?

BG: No, nothing at all. [both laugh] Not from the physics that we do. There are breakthroughs in technology-related things that make a lot of money. But ours is basic research and there are no patents that come out of it. No gadgets that are born. The Department of Energy funds us and at a reasonable level. It allows us to have some students and postdoctoral researchers, some travel money, but there are things we could do if we had more money. I’d love to have an institute that did combine more fully observational cosmology and fundamental basic research. We are heading toward that. We are looking for private money to do this. I can’t say that we are poor but it’s not the way; you get funding from private investors when there is some money to be made. There is no profit to be made in any of this.

RB: Thank you

BG: Thanks. It was fun.