Fabric of the Cosmos (part 1)

Transcript Fabric of the Cosmos Part 1

Kevin Harris: This is the podcast of Reasonable Faith with Dr. William Lane Craig. I'm Kevin Harris. We're going to tackle a very difficult question today, Dr. Craig. There's a new series on Nova for PBS with Brian Greene, The Fabric of the Cosmos – a four part series. It's very well done. The illustrations and the animation were just really well done. They interviewed physicists from all over the world on these topics, and lo' and behold as I watched this series, Dr. Craig, it's a lot of subjects that we talk about right here, and a lot of your work is involved, in particular the meaning and the definition of time, and the universe or a multiverse, and the fabric of the cosmos. What do you think about Brian Greene?

Dr. Craig: I think Brian Greene helps to popularize science for the layman in a dynamic, exciting way that makes it interesting. But what I've noticed about these popularizations of current science, Kevin, is that they all seem to follow a kind of familiar pattern that bothers me. And it's the same pattern that you see in these documentaries every Easter or Christmas about the historical Jesus; namely it's the sensational, the fringe theories, the outrageous views that get all the attention, rather than the good, normal, solid, well-established views. And I think this is because in the media today it's not exciting, it's not interesting, when dog bites man, it's when man bites dog that you get people's attention. And so all of these programs on contemporary popularizations of science seem to try to run the line that modern science is an outrage to common sense, that it's destroyed or called into question all of our normal perceptions about time and reality, and I frankly think that this is just sensationalism, by and large. It is really a misrepresentation of the serious science that's going on here in the favor of attention-grabbing sensationalism, and I think this program is really very guilty of that, frankly.

Kevin Harris: The producers of these programs have to produce a compelling show. They're non-scientific themselves, they're in an editing bay with script writers and they know that they have to get viewers, they have to get laypeople to watch this. It's got to be, as you say, the term is sexy; it's got to be sexy enough to watch. And I guess that many serious scientists are willing to capitulate that in that they, well, first of all, they don't have much of a choice if they're going to be in the program. And second of all, they would like the exposure, and so on. Now I'm not accusing Brian Greene of compromising or anything like that because perhaps his views really have been accurately shown in this piece, in this series.

Dr. Craig: Yes, that could well be. But I think what you discover is that professional physicists many times lack the philosophical training to make the conceptual distinctions that are important, to think clearly about the philosophical implications of these theories, and that's typically what these programs are about. For example, the idea that time is an illusion. That, I think, is a sensationalistic, attention-grabbing claim that has no solid basis in the science but some of these physicists may in fact believe it; others, I think, are simply quoted out of context.

Kevin Harris: Okay, and I'm pursuing this with you, Bill, because I want our listeners to be aware of how programming on TV is produced, in that you have to watch it carefully to see what the producers may be trying to portray rather than the people in the documentary itself. So that's a good point of yours. Alan Guth was quoted in it, and he said: “What is time? It's really the sixty-four thousand dollar question to physics.” And Brian Green says, “What is time? Basically, we don't know.”

Dr. Craig: Yes, now that's the odd thing about it. It begins by saying “Time is a mystery, we don't understand it, we don't know what it is,” and yet by the end of the program we're told that time may well be illusory, that time passes at different rates according to different observers, that the arrow of time is established by thermodynamic entropy increase. All sorts of things are told to us about the nature of time when, at least at the beginning of the program, we were told that time is a mystery which nobody really understands. This is just one of the fundamental contradictions in the whole program. [1]

Kevin Harris: Now there's a difference between the measurement of time and what time is – isn't there? They go through the program on how we began to measure time with pendulums, and things like that.

Dr. Craig: This is exactly, Kevin, one of the conceptual distinctions that needs to be made clearly and that gets blurred in a program like this. It begins by talking about clock measurements. It says no matter how accurate our clocks have become, time remains a mystery; clocks can tell us what time it is, but they haven't been able to tell us what time itself is, what it is we're actually measuring. So they make this distinction between time and our physical measurements of time using clock mechanisms. But then that distinction gets blurred in the program. It begins to talk about how fast time ticks, as time ticks along. Well, now, time doesn't tick along, Kevin. That's a metaphor. Clocks tick, not time. And yet by blurring time with what clocks do then we're told later that time runs more slowly for observers in relative motion to each other, rather than saying that their clocks run more slowly relative to each other. And then you begin to get these statements about the physical time keeping mechanisms applied to time itself.

In fact we shouldn’t even think about time itself as flowing. What we have here in this program is a collision between two radically different views of time that philosophers have helpfully distinguished. One is called a tensed theory of time or a dynamic theory of time; the other is called a tenseless theory of time or a static theory of time. According to the tensed theory of time the distinction between past, present, and future is an objective feature of reality. Temporal becoming is real; that is to say, things come into being and they go out of existence. By contrast on the tenseless view of time the distinction between past, present, and future is just an illusion of human consciousness. Really, all events in time are equally real and the distinction between past, present, and future is just a subjective illusion of human beings. And these two views of time are contrasted without naming them clearly in this program.

And it's important to understand that those who are partisans of the tensed theory of time do not think that time literally flows. This is universally acknowledged among philosophers of time who hold to the tensed view of time to be a metaphor for our experience of time. We experience time as passing, and it passes at different rates experientially depending on whether you're bored (in which case it passes slowly), or if you're busy (in which case time appears to pass quickly). But partisans of tensed time don't think that time literally flows along. Rather they would simply say temporal becoming is real, things come into and go out of existence, and there's a real difference between past, present, and future.

And so what happens in this documentary is that the flow of time is interpreted literally, it is identified with clock rates, and then by saying that clocks run more slowly or more quickly in certain circumstances, that time itself runs more slowly or more quickly. And I think you can see, I hope, that here you've just got an enormous conflation of ideas into this confused muddy waters that need to be made more conceptually distinct.

Kevin Harris: Yeah, and the illustrations didn't really help. You would think that animation and illustration would help in this. But one thing I was thinking was when they showed an instance of a clock slowing down, I thought, okay, now, what is the clock slowing down in reference to? Slowing down in reference to what? The clock may slow down, but you still have a measurement by which to gauge whether it's running faster or running slower that's kind of assumed and in the backdrop. And I thought, okay, well, they're going to bring Einstein into this.

Dr. Craig: Right, because he would say it's running slower relative to some other observer. [2] But what we need to understand is that there are different interpretations of the Special Theory of Relativity. What they're talking about here is the Special Theory of Relativity developed by Albert Einstein in 1905. What they don't tell you is that there are at least three different physical interpretations of the mathematical equations of Special Relativity. The only empirical evidence that we have for the Special Theory of Relativity would establish that the spatio-temporal coordinates of one observer are related to the spatio-temporal coordinates of another uniformly moving observer by a set of equations that are called the Lorentz transformation equations. That is the heart of the Special Theory of Relativity – that the spatio-temporal coordinates of these relativity moving observers are related by this set of mathematical equations named for the great Dutch physicist Hendrik Antoon Lorentz.

But beyond that it's a matter of interpretation how you're to understand this. Einstein's original interpretation was an interpretation of normal three-dimensional physical objects enduring though time. Lorentz's interpretation was quite different. Lorentz said, as you sort of indicated there, there is an absolute time relative to which clocks in motion run slowly, so that when a clock is in motion relative to the sort of fundamental reference frame then that clock will run slowly relative to that frame. But time itself it not relative, as it is in Einstein's interpretation. For Lorentz time itself is unaffected, it's our measurements of time which are affected by motion relative to the absolute reference frame. A third interpretation of relativity theory came along in 1908 from the German mathematician Herman Minkowski, and what Minkowski said in contraction to both Einstein and Lorentz, is that there really are no three-dimensional objects enduring through time, rather objects are four-dimensional. Just as they are extended in the three-dimensions of space – height, width and breadth – they have a fourth dimension in which they are extended, which is the dimension of time. So reality is really four-dimensional, and Minkowski unified time and space into one four-dimensional geometrical representation which he called spacetime.

Now, this program incorrectly attributes the spacetime formulation to Albert Einstein. That is not true. Einstein's original interpretation was an interpretation that had ordinary three-dimensional objects enduring through time, just as Newtonian physics did. The four-dimensional interpretation came along later with Minkowski and after Minkowski developed it Einstein adopted it himself. But that it is Minkowski's interpretation is evident in that the spacetime of Special Relativity is called Minkowski spacetime – it's named after Minkowski, it's not named after Einstein. So what this program is basically doing is plumping for a four-dimensional Minkowskian interpretation of the Special Theory of Relativity rather than the original Einsteinian view or a Lorentzian view.

Now, the problem is, Kevin, that these three physical interpretations are empirically equivalent. At least until very recently there's been no way to discover which one of them is correct because they all make the same empirical predictions. And yet Greene and some of the other persons in the program present the sort of textbook Minkowskian view of relativity theory as though this were in fact the truth, as though this were a scientific discovery, and it's not. And if I might here, I want to quote from an article that we did a podcast on on another occasion – an interview with professor Tim Maudlin, who is a very eminent contemporary philosopher of time. He speaks to this very issue. He says that,

Now that is a perfect characterization of Minkowski spacetime. Minkowski discovered that you can formulate the theory by imagining this four-dimensional geometry called spacetime, but people have elevated this mathematical representation to realty. They think that spacetime is not just a sort of diagrammatical way of portraying space and time on an axis, rather they think that this is reality, this is the way the world really is. And as Maudlin says, that is a philosophical or metaphysical jump or leap which has no justification in the science at all. It is an uncritical, naïve – philosophically naïve – interpretation of Minkowski spacetime, to be not just a diagrammatic way of representing reality but to be a sort of picture of reality itself. So Maudlin says, to answer “Why should physicists want to hand the subject of time over to philosophers?”:

So these are deep metaphysical questions which contemporary physicists are very ill-quipped to adjudicate.

Kevin Harris: Now, Bill, let me understand that one of your complaints here is that this particular series, The Fabric of the Cosmos from PBS and Nova, only presents the tenseless view of time, not the tensed view. It's a B-theory of time that they want to embrace.

Dr. Craig: That's another name for the tenseless theory, the B-theory of time; whereas the tensed view has been called the A-theory of time by philosophers.

Kevin Harris: A and B; okay.

Dr. Craig: Yes. And what it does is present the B-theory as though it has been established by these breakthrough discoveries in science that show that temporal becoming is illusory. They draw these vast metaphysical conclusions like the past, present, and future are equally real, and that tense is an illusion of human consciousness. As Maudlin says, these are all gratuitous. There are perfectly good interpretations of the equations that involve a tensed theory of time, including Einstein's original view in 1905 as well as Lorentz's view.

Kevin Harris: Brian Greene says that “Einstein would shake up the world with a radical insight into the nature of time.” He said, “Most people view time in a pretty simple straightforward way, time ticks the same for everyone everywhere.”

Dr. Craig: Yeah, see, the ticking; the conflation of clocks with time itself.

Kevin Harris: He says, “It's a commonsense picture established by the father of modern science, Isaac Newton.” But he goes on to say, “Sensible as Newton's picture of time may seem, Einstein realized it wasn't right. He discovered that time could run at different rates. As strange as it sounds, this means that time for me may not be the same as time for you. Einstein's discovery smashed Newton's conception of reality.” Now, that's what we've been talking about, Bill.

Dr. Craig: Sure; that's what we've been told.

Kevin Harris: Okay, so it's an embrace of one particular view out of the three of relativity, and also an embrace of the one particular view out of two views of time, the A-theory and the B-theory.

Dr. Craig: Yes, that's right. That's right, in favor of this sort of tenseless theory. And what's interesting, Kevin, is that he doesn't mention in this program that some of the most recent scientific evidence that's very exciting tend to vindicate Lorentz's interpretation, that there is absolute time and a sort of fundamental reference frame. And what I'm having reference here to is the measurement of faster than light particles at the accelerator in CERN in Switzerland. They have measured neutrinos traveling faster than the speed of light, and if there are such particles traveling at super-luminal velocities, on Einstein’s interpretation and Minkowski's this would mean that relative to some reference frames, these particles would go backwards in time. That means that the particle would literally be received at the receptor before it was ever sent from the transmitter, which is absurd. [6] So if you're going to avoid these sort of pathological situations what you have to say is that there is an absolute reference frame relative to which these super-luminal particles are moving, just as Lorentz believed, and that they do not go backwards in time at all, but that our clocks and our measuring instruments are affected by their motion relative to this absolute reference frame. So these recent discoveries actually fit very much better with a Lorentzian interpretation of relativity than the received view.

Kevin Harris: Bill, so often programs like this and physicists want to embrace the more mysterious, absurd notions; and you go, “That's absurd!” They go, “Ah, of course.”

Dr. Craig: Yes, exactly. This is what bothers me; it's the sensationalism.

Kevin Harris: It's the sound of one hand clapping. That's absurd. “Ah, now you understand.” [laughter]

Dr. Craig: Or it reminds me again of these historical Jesus programs where it's the apocryphal gospels, the gospel of Judas, the DaVinci Code, these flaky views that get all the attention because they're sensational. There seems to be a certain sort of standard shtick here in these science programs that the more they outrage common sense the better when in fact that's not at all required by the science.

Kevin Harris: By the way, the B-theory of time is a lot sexier than the A-theory of time because on the B-theory you can travel back in time – time travel is possible.

Dr. Craig: Right, that comes in on this program too, doesn't it?

Kevin Harris: It does in some of the illustrations. So it's more entertaining. I'm just trying to say that you can, wow, you can go back to the first grade!

Dr. Craig: Yes, though it has some, I think, absurd results. For example, if people are actually four-dimensional objects that are extended in time then the person that I see sitting across the table from me here – you – you're really not that whole object, you're just a slice of that object. You're like a slice of the loaf of bread. But what that means then, Kevin, is that the person I'm speaking to now is not the same person that was there one second ago because it's a different slice. So these are literally different objects. Now that means you're not the same person as the one who began listening to this program a few minutes ago. You are literally a different person. There is no personal identity over time on this tenseless theory, which I think is outrageous; it's just absurd. So I think there are all kinds of philosophical problems with this tenseless view that make it highly implausible.

Kevin Harris: We have run out of time. It has flown past, and we want to pick this up next time. In fact, Bill, on our next podcast, there's an illustration of what we're talking about that they do on this particular show. They use the animation of a person and an alien from another planet that they attempt to show that in fact the tenseless view of time, the B-theory, is the correct one. We'll look at that next time right here on Reasonable Faith. [7]