Frank Wilczek won the Nobel Prize in Physics in 2004 for work he did as a graduate student. He was also one of the earliest MacArthur Fellows, and he has won many other awards for his scientific work and writing. He is the author of several books, but most recently he has published a fantastic primer on the state of physics, called Fundamentals, Ten Keys to Reality. He s also written for the Wall Street Journal, and is currently a professor of physics at MIT and the Chief Scientist at the Wilcockski Quantum Center in Shanghai, China. And he also has appointments at Arizona State University, and Stockholm University, a busy, busy man. But before we jump in, I want to remind you that Frank is a wonderful explainer of physics and physics, and I really couldn t have asked for a better guide to this terrain than this one. And so, without further delay, I bring you the full tour of the world of physics: Frank's thoughts on the nature of physical reality, and what it means to be a scientist and a human being, and why we should all be curious about the world we live in it. And why it s important to have questions about the things we don t have answers about. And how we should ask them. And, of course, why we need to ask them, because they might be the most important thing we can learn about the universe we have ever learned about, and how we can make sense of it. And that s a question we should be asking the questions we can ask ourselves about it, not about it and how it s going to be understood, not by us in the universe what does it all really mean how it all work or how it works why it works? What does it matter? What is it all matter How it s all of it all make it all ? Why is it important to us to ask it, anyway? Why does it work? And why is it so important to ask the questions it s so well, anyway And what it s really important to know it? How can we know it, and understand it, really? Is it all possible is a question that we can have a better understanding of it? And how can we really know it better than we really do who really does when it s real? and why it matters?
00:37:51.200point of view of the fundamental equation of physics as any one time. There are alternative times that are just as good. Now, that's about the fundamental equations. It's not about the world we actually experience, of course, because there is a preferred time, namely the time that points back to the Big Bang and the uniform space. But you're saying that in a different frame of reference, one set of observers could say that A preceded B, but another set of observers could say that A preceded B, but another set of observers,
00:37:51.220moving with respect to A preceded B, but another set could say that A preceded A. Yes, right. And that falls out of Einstein's special theory of relativity. Yes. So there is that possibility. But on the other hand, observers can also agree that some events definitely precede others. So there's kind of another world, which is called the space-like region, but there's also a time-like region where you can order things linearly. Anyway, I mean,
00:38:20.640the special relativity is a fascinating theory. And we could discuss it easily for several hours. But for present purposes, it made the traditional separation into a unique time and space unstable. Now, there are other versions of time that mix in some space and have,
00:38:48.520but are just as good, but are just as good as far as the fundamental equations are concerned.
00:38:53.200Well, does the fact that there's a preferred frame, at least defined with respect to the Big Bang, give us a notion of simultaneity that is valid? I mean, is there some place from which I can say now?
00:39:08.440In cosmology, yeah. In cosmology, we commonly use that language. When we say, for instance, that a given star was formed ump-dity-ump seconds after the Big Bang, we can say that about distant stars.
00:39:28.300And there's a unique definition, because there's this preferred frame in which the universe, the distribution of galaxies looks uniform.
00:39:38.160If you move relative to that frame, then it won't look uniform. There may be some distortion, and the colors won't be quite uniform either. And so there is a preferred frame.
00:39:52.300And so there's a preferred rest frame, and you commonly in cosmology use that as a way of synchronizing times across distant galaxies.
00:40:05.900So, but in everyday life, as opposed to cosmology, the different frames are more or less equivalent. If you cancel out the astrological influence of distant galaxies, so to speak, what's left allows you freedom in the definition of time. There are many times that are equally good.
00:40:27.360Okay. Okay, so we have a space-time continuum of some kind, which is a, it is a kind of medium, right? I mean, it is the kind of...
00:40:37.980Oh, that's the other thing, right. That's the other thing, is that when you go to the more advanced parts of physics, from special relativity to general relativity in particular, then you find that it's very, very convenient and really unavoidable,
00:40:55.620unless you are satisfied with extremely ugly equations. It's very, very convenient to treat the three dimensions of space and one dimension of time as a unified structure, because the equations display tremendous symmetry between space and time.
00:41:16.480There are still distinctions, but there's also tremendous symmetry between space and time, and there, you can only separate them at the cost of making the equations very unnatural.
00:41:30.420Right, but also we have, you know, further phenomenon like gravity, which seem best explained in terms of space-time itself being the sort of thing that can bend, right?
00:41:42.820Exactly, right. That's the leading idea of the general theory of relativity. And as I said, it's very difficult to formulate the bending equations in an elegant way without explicitly bringing in the idea of space and time as a uniform,
00:41:59.800as a coherent, integrated, three-plus-one-dimensional entity.
00:42:04.400Okay, so we have this context of our experience. We have this condition of space-time, which now, disconcertingly, we've learned is not just a mere context in which the things that exist can happen. Rather, it is a kind of thing itself, right?
00:42:27.460That's right. It's not a void. That notion was something that famously Aristotle rejected, and most thinkers rejected until Newtonian physics, which works very, very well with space being just sort of an empty platform or stage through which particles move.
00:42:55.840But in modern physics, we've reinstated space-time as a substance, I would say.
00:43:03.360It has a life of its own in many ways. The primary entities we use to describe the world are all core fields, and actually quantum fields, but they're space-filling entities that vibrate.
00:43:17.560And the things that we call particles are excitations within these fields, but they fill all space and all time, and the elegant description of how they work uses that description.
00:43:30.460And most dramatically, space-time itself is like an elastic medium that can bend and warp, and in the general theory of relativity, the kinds of distortions of motion we call gravity are ascribed to that bending and warping of space-time in very successful equations.
00:43:51.120And we also, in very recent years, have learned that so-called empty space actually weighs something.
00:43:59.220This is called the dark energy. Einstein called it the cosmological constant.
00:44:04.480But basically what it is, is that space-time itself has an intrinsic density.
00:44:10.780So, you know, it's a substance by a, it's a very respectable substance by any reasonable definition.
00:44:21.300Okay, so again, we'll see if we can somehow conserve our intuitions, or at least notice when we're violating them here in building up this picture.
00:44:29.920So we have this, people are listening to us, let's assume their eyes are open, or they can open their eyes,
00:44:37.280and, you know, they see the space in front of them, occupied by, you know, the objects on their desk, and perhaps their hands.
00:44:46.160If they wave their hands in front of them, they can feel the air, right, which is yet more stuff in this, what once seemed like a void-like condition.
00:44:55.240But what we're now being told, that this condition, the only place in which they experience their own being,
00:45:04.120has all kinds of structure that is not apparent, and which is really only fully captured in the mathematical devices and discoveries we've used to tease out this structure.
00:45:18.560I guess, but before we jump further into the constituents of things, do you have any thought as to why mathematics works here?
00:45:27.380I remember that Eugene Wigner wrote a paper, I think in 1960 or so, about the, what he called the unreasonable effectiveness of mathematics in the natural sciences.
00:45:39.660I mean, it just seems a very strange accident that apes like ourselves have enough linguistic ability, or at least some of us do,
00:45:49.520to develop a symbol system that produces not only an uncannily powerful description of what we can understand,
00:46:03.760It points into the darkness of nature and suggests what we might find there, and then lo and behold, we find those things,
00:46:12.140whether it's, you know, the absurd energy in the center of an atom, or more of the electromagnetic spectrum that we can't see with our unaided eyes.
00:46:27.860It's rock bottom, and it doesn't have, it didn't have to be that way.
00:46:30.960I mean, it's, it's, I think, I think, I think it's been a continue, a continuous revelation and surprise and gift as science has developed.
00:46:43.780Certainly, you know, since, since the 17th century, a sort of modern science where we make extreme demands of accuracy and, and test things very hard and so forth.
00:46:53.820It's been, it's been, it's been, the program is to try to understand things fully and deeply and probe with all the accuracy we can muster and get, at the same time, try to boil down what we find into as compact a description as possible.
00:47:18.180Even if the description has to be kind of an unusual language, which we call mathematics, that's very different from what we hear at cradles.
00:47:30.320And, and, and, and surprise after surprise, more and more layers, you know, Newton's theory of gravity, and then Maxwell's electrodynamics, and then quantum mechanics, and relativity, and quantum chromodynamics.
00:47:43.760And the equations get more structured in some ways, but I think there's a tendency that they've actually gotten more beautiful and certainly more comprehensible, and more comprehensive, less comprehensible, maybe more comprehensive.
00:47:59.300So that now, I think we've gotten very close, if not to the rock bottom foundation of understanding how ordinary matter works.
00:48:11.360So sufficient for biology, chemistry, and all forms of engineering.
00:48:17.360And we can summarize it in a few equations.
00:48:21.700That's what, that's why I say it's, it's a gift.
00:48:24.020For instance, and, and, and I think there's an important thought experiment, you can imagine, and people have imagined, and people, you know, even have gone off the deep end on this, but, but you can imagine that someday, artificial intelligences will be fully embodied, and general intelligences within computers.
00:48:49.160And you could even imagine that these artificial intelligences were not sensing the same world that we're sensing, that they, they would be sensing electronic inputs that were designed by some programmer.
00:49:03.440So this would be, these would be worlds in which intelligent design is actually true.
00:49:38.100I mean, following that argument, couldn't we be in a simulation wherein we're no more in touch with the base layer of reality, but it's just our simulation is consistent in all the mathematically satisfying ways, or at least seems to be thus far?
00:49:53.080It could be, but it would be very, very wasteful programming practice to sort of hide so much complexity inside useless things that, that don't directly support the, presumably the interesting thoughts that are going on or the interesting games.
00:50:11.360If you think about a super Mario world or something, if I were programming super Mario, I wouldn't make the bricks out of quantum mechanical atoms.
00:50:20.320It's just, it's just, it's just an awful waste to do that.
00:50:24.600And, and, and also you're, you know, you, you really could make a lot of creative use out of having more than one version of time, for instance.
00:50:34.000I mean, you could have astrology being true.
00:50:35.980You could have people moving back and forth doing time travel.
00:50:39.540You could have all kinds of things once, once you free yourself of constraints that we seem to have in our actual physical reality, but that doesn't seem to be the world we live in for better or worse.
00:51:00.740Because, you know, intelligent design.
00:51:02.960So I'm sort of joking, but not really.
00:51:06.660That's what intel, I think intelligent design is maybe the future, but I just don't see much evidence for it in the world we actually experience.