Transcript
00:00:00 The following is a conversation with Frank Wilczek,
00:00:02 a theoretical physicist at MIT who won the Nobel Prize
00:00:07 for the co discovery of asymptotic freedom
00:00:09 in the theory of strong interaction.
00:00:12 Quick mention of our sponsors,
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00:00:20 Check them out in the description to support this podcast.
00:00:23 As a side note, let me say a word about asymptotic freedom.
00:00:26 Protons and neutrons make up the nucleus of an atom.
00:00:30 Strong interaction is responsible
00:00:31 for the strong nuclear force that binds them.
00:00:34 But strong interaction also holds together the quarks
00:00:37 that make up the protons and neutrons.
00:00:40 Frank Wilczek, David Gross, and David Politzer
00:00:43 came up with a theory postulating
00:00:45 that when quarks come really close to one another,
00:00:48 the attraction abates and they behave like free particles.
00:00:51 This is called asymptotic freedom.
00:00:54 This happens at very, very high energies,
00:00:57 which is also where all the fun is.
00:01:00 This is the Lex Friedman Podcast,
00:01:02 and here is my conversation with Frank Wilczek.
00:01:07 What is the most beautiful idea in physics?
00:01:10 The most beautiful idea in physics
00:01:13 is that we can get a compact description of the world
00:01:19 that’s very precise and very full
00:01:22 at the level of the operating system of the world.
00:01:28 That’s an extraordinary gift.
00:01:32 And we get worried when we find discrepancies
00:01:38 between our description of the world
00:01:41 and what’s actually observed
00:01:43 at the level even of a part in a billion.
00:01:46 You actually have this quote from Einstein
00:01:49 that the most incomprehensible thing
00:01:51 about the universe is that it is comprehensible,
00:01:54 something like that.
00:01:55 Yes, so that’s the most beautiful surprise
00:01:58 that I think that really was to me the most profound result
00:02:05 of the scientific revolution of the 17th century
00:02:08 with the shining example of Newtonian physics
00:02:13 that you could aspire to completeness, precision,
00:02:17 and a concise description of the world,
00:02:20 of the operating system.
00:02:21 And it’s gotten better and better over the years
00:02:25 and that’s the continuing miracle.
00:02:27 Now, there are a lot of beautiful sub miracles too.
00:02:30 The form of the equations is governed
00:02:33 by high degrees of symmetry
00:02:35 and they have a very surprising kind
00:02:39 of mind expanding structure,
00:02:40 especially in quantum mechanics.
00:02:42 But if I had to say the single most beautiful revelation
00:02:47 is that, in fact, the world is comprehensible.
00:02:53 Would you say that’s a fact or a hope?
00:02:56 It’s a fact.
00:02:58 We can do, you can point to things like
00:03:02 the rise of gross national products per capita
00:03:11 around the world as a result of the scientific revolution.
00:03:14 You can see it all around you.
00:03:15 And recent developments with exponential production
00:03:21 of wealth, control of nature at a very profound level
00:03:27 where we do things like sense tiny, tiny, tiny, tiny
00:03:31 vibrations to tell that there are black holes
00:03:35 colliding far away or we test laws as I alluded to
00:03:40 whether it’s part in a billion and do things
00:03:45 in what appear on the surface
00:03:47 to be entirely different conceptual universes.
00:03:49 I mean, on the one hand, pencil and paper
00:03:52 are nowadays computers that calculate abstractions
00:03:55 and on the other hand, magnets and accelerators
00:03:58 and detectors that look at the behavior
00:04:00 of fundamental particles and these different universes
00:04:05 have to agree or else we get very upset
00:04:08 and that’s an amazing thing if you think about it.
00:04:12 And it’s telling us that we do understand a lot
00:04:18 about nature at a very profound level
00:04:21 and there are still things we don’t understand of course
00:04:25 but as we get better and better answers
00:04:28 and better and better ability to address difficult questions
00:04:32 we can ask more and more ambitious questions.
00:04:35 Well, I guess the hope part of that is because
00:04:38 we are surrounded by mystery.
00:04:40 So one way to say it, if you look at the growth GDP
00:04:45 over time that we figured out quite a lot
00:04:47 and we’re able to improve the quality of life
00:04:50 because of that and we’ve figured out some fundamental things
00:04:53 about this universe but we still don’t know
00:04:55 how much mystery there is and it’s also possible
00:04:58 that there’s some things that are in fact incomprehensible
00:05:03 to both our minds and the tools of science.
00:05:07 Like the sad thing is we may not know it
00:05:11 because in fact they are incomprehensible
00:05:14 and that’s the open question is how much
00:05:16 of the universe is comprehensible?
00:05:18 If we figured out everything what’s inside the black hole
00:05:23 and everything that happened at the moment of the Big Bang
00:05:26 does that still give us the key
00:05:28 to understanding the human mind
00:05:30 and the emergence of all the beautiful complexity
00:05:33 we see around us?
00:05:35 That’s not like when I see these objects
00:05:38 like I don’t know if you’ve seen them like cellular automata
00:05:41 all these kinds of objects where the from simple rules
00:05:44 emerges complexity, it makes you wonder maybe
00:05:48 it’s not reducible to simple beautiful equations
00:05:52 the whole thing only parts of it.
00:05:54 That’s the tension I was getting at with the hope.
00:05:57 Well, when we say the universe is comprehensible
00:06:00 we have to kind of draw careful distinctions
00:06:04 about or definitions about what we mean by that.
00:06:12 Both the universe and the kind of and the comprehensive.
00:06:15 Exactly, right so the so in certain areas
00:06:22 of understanding reality we’ve made extraordinary progress
00:06:27 I would say in understanding fundamental physical processes
00:06:32 and getting very precise equations that really work
00:06:35 and allow us to do the profound sculpting of matter
00:06:40 to make computers and iPhones and everything else
00:06:43 and they really work and they’re extraordinary productions
00:06:48 on the other but and that’s all based
00:06:51 on the laws of quantum mechanics
00:06:53 and they really work and they give us tremendous control
00:06:59 of nature on the other hand as we get better answers
00:07:04 we can also ask more ambitious questions
00:07:07 and there are certainly things that have been observed
00:07:11 even in what would be usually called the realm of physics
00:07:15 that aren’t understood for instance there seems to be
00:07:19 another source of mass in the universe
00:07:21 the so called dark matter that we don’t know what it is
00:07:25 and it’s a very interesting question what it is then
00:07:30 but also as you were alluding to there’s it’s one thing
00:07:34 to know the basic equations it’s another thing
00:07:38 to be able to solve them in important cases
00:07:42 so we run up against the limits of that
00:07:45 in things like chemistry where we’d like to be able
00:07:48 to design molecules and predict their behavior
00:07:51 from the equations we think the equations could do that
00:07:54 in principle but in practice it’s very challenging
00:07:59 to solve them in all but very simple cases
00:08:04 and then there’s the other thing which is that a lot
00:08:07 of what we’re interested in is historically conditioned
00:08:11 it’s not a matter of the fundamental equations
00:08:15 but about what has evolved or come out
00:08:19 of the early universe and formed into people and frogs
00:08:23 and societies and things and the laws of physics
00:08:27 the basic laws of physics only take you so far
00:08:30 in that it kind of provides a foundation
00:08:32 but doesn’t really that you need entirely different concepts
00:08:35 to deal with those kind of systems
00:08:39 and one thing I can say about that is that the laws
00:08:46 themselves point out their limitations
00:08:48 that they kind of their laws for dynamical evolution
00:08:53 so they tell you what happens if you have
00:08:55 a certain starting point but they don’t tell you
00:08:57 what the starting point should be at least yeah
00:09:01 and the other thing that emerges
00:09:05 from the equations themselves is the phenomena
00:09:09 of chaos and sensitivity to initial conditions
00:09:14 which tells us that you have that there are intrinsic
00:09:20 limitations on how well we can spell out the consequences
00:09:24 of the laws if we try to apply them.
00:09:26 It’s the old apple pie if you want to what is it
00:09:28 make an apple pie from scratch you have to build
00:09:32 the universe or something like that.
00:09:34 Well you’re much better off starting with apples
00:09:37 than starting with quarks let’s put it that way.
00:09:39 In your book A Beautiful Question you ask
00:09:42 does the world embody beautiful ideas?
00:09:44 So the book is centered around this very interesting
00:09:48 question it’s like Shakespeare you can like dig in
00:09:50 and read into all the different interpretations
00:09:52 of this question but at the high level what to use
00:09:56 the connection between beauty of the world
00:09:59 and physics of the world.
00:10:02 In a sense we now have a lot of insight into what
00:10:05 the laws are the form they take that allow us
00:10:09 to understand matter in great depth and control it
00:10:13 as we’ve discussed and it’s an extraordinary thing
00:10:19 how mathematically ideal those equations turn out to be.
00:10:26 In the early days of Greek philosophy Plato had this model
00:10:33 of atoms built out of the five perfectly symmetrical
00:10:37 platonic solids so there was somehow the idea
00:10:39 that mathematical symmetry should govern the world
00:10:44 and we’ve out Platoed Plato by far in modern physics
00:10:49 because we have symmetries that are much more extensive
00:10:52 much more powerful that turn out to be the ingredients
00:10:56 out of which we construct our theory of the world
00:10:59 and it works and so that’s certainly beautiful.
00:11:04 So the idea of symmetry which is a driving inspiration
00:11:13 in much of human art especially decorative art
00:11:18 like the Alhambra or wallpaper designs or things
00:11:22 you see around you everywhere also turns out to be
00:11:26 the dominant theme in modern fundamental physics
00:11:30 symmetry and its manifestations the laws turn out
00:11:33 to be very to have these tremendous amounts of symmetry
00:11:36 you can change the symbols and move them around
00:11:38 in different ways and they still have the same consequences.
00:11:45 So that’s beautiful that these concepts that humans
00:11:59 find appealing also turn out to be the concepts
00:12:03 that govern how the world actually works.
00:12:07 I don’t think that’s an accident.
00:12:09 I think humans were evolved to be able to interact
00:12:13 with the world in ways that are advantageous
00:12:17 and to learn from it and so we are naturally evolved
00:12:21 or designed to enjoy beauty and it’s a symmetry
00:12:24 and the world has it and that’s why we resonate with it.
00:12:29 Well it’s interesting that the ideas of symmetry
00:12:33 emerge at many levels of the hierarchy of the universe.
00:12:40 So you’re talking about particles but it also is
00:12:44 at the level of chemistry and biology
00:12:47 and the fact that our cognitive sort of our perception
00:12:55 system and whatever our cognition is also finds
00:12:59 it appealing or somehow our sense of what is beautiful
00:13:02 is grounded in this idea of symmetry
00:13:05 or the breaking of symmetry.
00:13:06 Symmetry is at the core of our conception of beauty
00:13:09 whether it’s the breaking or the non breaking
00:13:11 of the symmetry.
00:13:12 It makes you wonder why.
00:13:17 Why?
00:13:20 So I come from Russia and the question of Dostoevsky
00:13:23 he has said that beauty will save the world.
00:13:27 Maybe as a physicist you can tell me
00:13:29 what do you think he meant by that?
00:13:31 I don’t know if it saves the world
00:13:32 but it does turn out to be a tremendous source
00:13:35 of insight into the world.
00:13:37 When we investigate kind of the most fundamental
00:13:42 interactions, things that are hard to access
00:13:46 because they occur at very short distances
00:13:48 between very special kinds of particles
00:13:53 whose properties are only revealed at high energies.
00:14:01 We don’t have much to go on from everyday life
00:14:04 but so we have when we guess what the,
00:14:06 and the experiments are difficult to do
00:14:08 so you can’t really follow a very wholly empirical procedure
00:14:14 to sort of in the Baconian style figure out the laws
00:14:20 kind of step by step just by accumulating a lot of data
00:14:23 what we actually do is guess.
00:14:25 And the guesses are kind of aesthetic really.
00:14:29 What would be a nice description
00:14:31 that’s consistent with what we know
00:14:34 and then you try it out and see if it works
00:14:36 and by gosh it does in many profound cases.
00:14:42 So there’s that but there’s another source of symmetry
00:14:46 which I didn’t talk so much about in a beautiful question
00:14:51 but does relate to your comments
00:14:56 and I think very much relates to the source of symmetry
00:15:02 that we find in biology and in our heads, you know,
00:15:08 in our brain which is that, well it is discussed a bit
00:15:15 in a beautiful question and also in fundamentals
00:15:20 is that when you have, symmetry is also a very important
00:15:28 means of construction.
00:15:30 So when you have for instance simple viruses
00:15:34 that need to construct their coat, their protein coat,
00:15:39 the coats often take the form of platonic solids
00:15:43 and the reason is that the viruses are really dumb
00:15:47 and they only know how to do one thing
00:15:49 so they make a pentagon then they make another pentagon
00:15:51 and they make another pentagon
00:15:52 and they all glue together in the same way
00:15:55 and that makes a very symmetrical object sort of.
00:15:58 So the rules of development when you have simple rules
00:16:02 and they work again and again, you get symmetrical patterns.
00:16:07 That’s kind of, in fact it’s a recipe also
00:16:09 for generating fractals, like the kind of broccoli
00:16:14 that has all this internal structure
00:16:19 and I wish I had a picture to show
00:16:20 but maybe people remember it from the supermarket
00:16:26 and you say how did a vegetable get so intelligent
00:16:30 to make such a beautiful object
00:16:31 with all this fractal structure
00:16:33 and the secret is stupidity.
00:16:35 You just do the same thing over and over again
00:16:38 and in our brains also, you know, we came out,
00:16:43 we start from single cells and they reproduce
00:16:47 and each one does basically roughly the same thing.
00:16:54 The program evolves in time, of course,
00:16:56 different modules get turned on and off,
00:17:01 different regions of the genetic code
00:17:03 get turned on and off but basically,
00:17:06 a lot of the same things are going on
00:17:08 and they’re simple things
00:17:09 and so you produce the same patterns over and over again
00:17:12 and that’s a recipe for producing symmetry
00:17:14 because you’re getting the same thing in many, many places
00:17:17 and if you look at, for instance,
00:17:20 the beautiful drawings of Roman Icahal,
00:17:24 the great neuroanatomist who drew the structure
00:17:29 of different organs like the hippocampus,
00:17:33 you see it’s very regular and very intricate
00:17:37 and it’s symmetry in that sense
00:17:43 because it’s many repeated units
00:17:46 that you can take from one place to the other
00:17:49 and see that they look more or less the same.
00:17:51 But what you’re describing, this kind of beauty
00:17:54 that we’re talking about now is a very small sample
00:17:58 in terms of space time in a very big world
00:18:01 in a very short, brief moment in this long history.
00:18:08 In your book, Fundamentals, 10 Keys to Reality,
00:18:11 I’d really recommend people read it.
00:18:14 You say that space and time are pretty big or very big.
00:18:20 How big are we talking about?
00:18:21 Can you tell a brief history of space and time?
00:18:26 It’s easy to tell a brief history, but the details get very
00:18:30 involved, of course, but one thing I’d like to say
00:18:33 is that if you take a broad enough view,
00:18:37 the history of the universe is simpler
00:18:38 than the history of Sweden, say,
00:18:40 because your standards are lower.
00:18:45 But just to make it quantitative,
00:18:49 I’ll just give a few highlights.
00:18:51 And it’s a little bit easier to talk about time,
00:18:55 so let’s start with that.
00:18:57 The Big Bang occurred, we think.
00:19:00 The universe was much hotter and denser and more uniform
00:19:03 about 13.8 billion years ago,
00:19:07 and that’s what we call the Big Bang.
00:19:10 And it’s been expanding and cooling,
00:19:12 the matter in it has been expanding and cooling ever since.
00:19:16 So in a real sense, the universe is 13.8 billion years old.
00:19:20 That’s a big number, kind of hard to think about.
00:19:24 A nice way to think about it, though,
00:19:26 is to map it onto one year.
00:19:29 So let’s say the universe just linearly mapped
00:19:32 the time intervals from 13.8 billion years onto one year.
00:19:37 So the Big Bang then is on January 1st at 12 a.m.
00:19:43 And you wait for quite a long time
00:19:49 before the dinosaurs emerge.
00:19:51 The dinosaurs emerge on Christmas, it turns out.
00:19:55 And…
00:19:55 12 months, almost 12 months later.
00:19:57 Getting close to the end, yes.
00:19:59 Getting close to the end.
00:20:01 And the extinction event that let the mammals
00:20:05 and ultimately humans inherit the Earth
00:20:08 from the dinosaurs occurred on December 30th.
00:20:13 And all of human history is a small part of the last day.
00:20:18 And so, yes, so we’re occupying only,
00:20:23 and a human lifetime is a very, very infinitesimal part
00:20:26 of this interval of these gigantic cosmic reaches of time.
00:20:35 And in space, we can tell a very similar story.
00:20:39 In fact, it’s convenient to think that the size
00:20:44 of the universe is the distance that light can travel
00:20:48 in 13.8 billion years.
00:20:50 So it’s 13.8 billion light years.
00:20:54 That’s how far you can see out.
00:20:56 That’s how far signals can reach us.
00:21:01 And that is a big distance.
00:21:06 That is a big distance because compared to that, the Earth
00:21:14 is a fraction of a light second.
00:21:18 So again, it’s really, really big.
00:21:21 And so if we wanna think about the universe
00:21:27 as a whole in space and time,
00:21:30 we really need a different kind of imagination.
00:21:35 It’s not something you can grasp
00:21:41 in terms of psychological time in a useful way.
00:21:44 You have to think, you have to use exponential notation
00:21:47 and abstract concepts to really get any hold
00:21:51 on these vast times and spaces.
00:21:56 On the other hand, let me hasten to add
00:21:58 that that doesn’t make us small
00:22:00 or make the time that we have to us small.
00:22:06 Because again, looking at those pictures
00:22:10 of what our minds are and some of the components
00:22:15 of our minds, these beautiful drawings
00:22:18 of the cellular patterns inside the brain,
00:22:21 you see that there are many, many, many processing units.
00:22:24 And if you analyze how fast they operate,
00:22:29 I tried to estimate how many thoughts
00:22:31 a person can have in a lifetime.
00:22:33 That’s kind of a fuzzy question,
00:22:34 but I’m very proud that I was able
00:22:36 to define it pretty precisely.
00:22:39 And it turns out we have time for billions
00:22:43 of meaningful thoughts in a lifetime.
00:22:46 So it’s a lot.
00:22:48 We shouldn’t think of ourselves as terribly small
00:22:51 either in space or in time,
00:22:53 because although we’re small in those dimensions
00:22:57 compared to the universe, we’re large compared
00:23:01 to meaningful units of processing information
00:23:05 and being able to conceptualize and understand things.
00:23:11 Yeah, but 99% of those thoughts are probably food,
00:23:15 sex, or internet related.
00:23:16 Well, yeah, well, they’re not necessarily, that’s right.
00:23:20 Only like point one is Nobel Prize winning ideas.
00:23:24 That’s true, but there’s more to life
00:23:26 than winning Nobel Prizes.
00:23:27 How did you do that calculate?
00:23:29 Can you maybe break that apart a little bit,
00:23:31 just kind of for fun, sort of an intuition
00:23:34 of how we calculate the number of thoughts?
00:23:35 The number of thoughts, right.
00:23:37 It’s necessarily imprecise because a lot of things
00:23:40 are going on in different ways and what is a thought.
00:23:43 But there are several things that point
00:23:45 to more or less the same rate of being able
00:23:50 to have meaningful thoughts.
00:23:52 For instance, the one that I think is maybe
00:23:57 the most penetrating is how fast
00:24:01 we can process visual images.
00:24:04 How do we do that?
00:24:07 If you’ve ever watched old movies,
00:24:11 you can see that, well, any movie, in fact,
00:24:15 a motion picture is really not a motion picture.
00:24:18 It’s a series of snapshots that are playing
00:24:20 one after the other and it’s because our brains
00:24:25 also work that way.
00:24:26 We take snapshots of the world, integrate over a certain time
00:24:29 and then go on to the next one and then by post processing,
00:24:33 create the illusion of continuity and flow,
00:24:37 we can deal with that.
00:24:38 And if the flicker rate is too slow,
00:24:44 then you start to see that it’s a series of snapshots
00:24:48 and you can ask, what is the crossover?
00:24:51 When does it change from being something
00:24:53 that is matched to our processing speed versus too fast?
00:24:57 And it turns out about 40 per second.
00:25:00 And then if you take 40 per second as how well,
00:25:04 how fast we can process visual images,
00:25:06 you get to several billions of thoughts.
00:25:10 If you, similarly, if you ask what are some
00:25:14 of the fastest things that people can do?
00:25:16 Well, they can play video games,
00:25:18 they can play the piano very fast if they’re skilled at it.
00:25:22 And again, you get to similar units
00:25:25 or how fast can people talk?
00:25:27 You get to similar, you know,
00:25:28 within a couple of orders of magnitude,
00:25:30 you get more or less to the same idea.
00:25:33 So that’s how you can say that there’s billions
00:25:38 of meaningful, there’s room for billions
00:25:40 of meaningful thoughts.
00:25:42 I won’t argue for exactly two billion versus 1.8 billion.
00:25:47 It’s not that kind of question,
00:25:49 but I think any estimate that’s reasonable
00:25:52 will come out within, say, 100 billion and 100 million.
00:25:58 So it’s a lot.
00:26:01 It would be interesting to map out
00:26:04 for an individual human being the landscape of thoughts
00:26:07 that they’ve sort of traveled.
00:26:09 If you think of thoughts as a set of trajectories,
00:26:14 what that landscape looks like.
00:26:16 I mean, I’ve been recently really thinking
00:26:19 about this Richard Dawkins idea of memes
00:26:24 and just all this ideas and the evolution of ideas
00:26:27 inside of one particular human mind
00:26:30 and how they’re then changed and evolved
00:26:33 by interaction with other human beings.
00:26:36 It’s interesting to think about.
00:26:38 So if you think the number is billions,
00:26:41 you think there’s also social interaction.
00:26:44 So these aren’t like there’s interaction
00:26:48 in the same way you have interaction with particles.
00:26:50 There’s interaction between human thoughts
00:26:53 that perhaps that interaction in itself
00:26:56 is fundamental to the process of thinking.
00:26:59 Like without social interaction,
00:27:01 we would be like stuck, like walking in a circle.
00:27:04 We need the perturbation of other humans
00:27:07 to create change and evolution.
00:27:09 Once you bring in concepts of interactions
00:27:13 and correlations and relations,
00:27:15 then you have what’s called a combinatorial explosion
00:27:20 that the number of possibilities expands exponentially
00:27:24 technically with the number of things you’re considering.
00:27:28 And it can easily rapidly outstrip these billions
00:27:34 of thoughts that we’re talking about.
00:27:36 So we definitely cannot by brute force
00:27:41 master complex situations
00:27:45 or think of all the possibilities in a complex situations.
00:27:48 I mean, even something as relatively simple as chess
00:27:53 is still something that human beings
00:27:56 can’t comprehend completely.
00:27:57 Even the best players lose, still sometimes lose
00:28:00 and they consistently lose to computers these days.
00:28:05 And in computer science, there’s a concept of NP complete.
00:28:08 So large classes of problems when you scale them up
00:28:12 beyond a few individuals become intractable.
00:28:16 And so that in that sense, the world is inexhaustible.
00:28:21 And that makes it beautiful that we can make any laws
00:28:25 that generalize efficiently and well
00:28:29 can compress all of that combinatorial complexity
00:28:32 just like a simple rule.
00:28:33 That in itself is beautiful.
00:28:35 It’s a happy situation.
00:28:36 And I think that we can find general principles
00:28:43 of sort of of the operating system
00:28:45 that are comprehensible, simple, extremely powerful
00:28:49 and let us control things very well
00:28:52 and ask profound questions.
00:28:55 And on the other hand,
00:28:56 that the world is going to be inexhaustible.
00:28:59 That once we start asking about relationships
00:29:03 and how they evolve and social interactions
00:29:06 and we’ll never have a theory of everything
00:29:10 in any meaningful sense because that.
00:29:13 Of everything, everything, truly everything is.
00:29:17 Can I ask you about the Big Bang?
00:29:19 So we talked about the space and time are really big.
00:29:24 But then, and we humans give a lot of meaning
00:29:27 to the word space and time in our like daily lives.
00:29:33 But then can we talk about this moment of beginning
00:29:37 and how we’re supposed to think about it?
00:29:40 That at the moment of the Big Bang,
00:29:42 everything was what, like infinitely small
00:29:46 and then it just blew up?
00:29:48 We have to be careful here
00:29:49 because there’s a common misconception
00:29:53 that the Big Bang is like the explosion of a bomb
00:29:58 in empty space that fills up the surrounding place.
00:30:02 It is space.
00:30:03 It is, yeah.
00:30:05 As we understand it, it’s the fact,
00:30:08 it’s the fact or the hypothesis,
00:30:12 but well supported up to a point
00:30:14 that everywhere in the whole universe,
00:30:19 early in the history,
00:30:24 matter came together into a very hot, very dense,
00:30:28 if you run it backwards in time,
00:30:29 matter comes together into a very hot, very dense
00:30:32 and yet very homogeneous plasma
00:30:36 of all the different kinds of elementary particles
00:30:39 and quarks and anti quarks and gluons
00:30:41 and photons and electrons and anti electrons,
00:30:43 everything, all of that stuff.
00:30:45 Like really hot.
00:30:46 Really, really, really hot.
00:30:49 We’re talking about way, way hotter
00:30:52 than the surface of the sun.
00:30:56 Well, in fact, if you take the equations as they come,
00:31:00 the prediction is that the temperature
00:31:02 just goes to infinity,
00:31:04 but then the equations break down.
00:31:06 We don’t really, there are various,
00:31:10 the equations become infinity equals infinity,
00:31:12 so they don’t feel that it’s called a singularity.
00:31:15 We don’t really know.
00:31:16 This is running the equations backwards,
00:31:19 so you can’t really get a sensible idea
00:31:21 of what happened before the Big Bang.
00:31:23 So we need different equations
00:31:25 to address the very earliest moments.
00:31:31 But so things were hotter and denser.
00:31:35 We don’t really know why things started out that way.
00:31:40 We have a lot of evidence that they did start out that way.
00:31:43 But since most of the,
00:31:51 we don’t get to visit there and do controlled experiments.
00:31:55 Most of the record is very, very processed
00:31:59 and we have to use very subtle techniques
00:32:05 and powerful instruments to get information
00:32:09 that has survived.
00:32:11 Get closer and closer to the Big Bang.
00:32:14 Get closer and closer to the beginning of things.
00:32:16 And what’s revealed there is that, as I said,
00:32:22 there undoubtedly was a period
00:32:25 when everything in the universe
00:32:26 that we have been able to look at and understand,
00:32:30 and that’s consistent with everything,
00:32:33 is in a condition where it was much, much hotter
00:32:41 and much, much denser,
00:32:44 but still obeying the laws of physics
00:32:46 as we know them today.
00:32:48 And then you start with that.
00:32:51 So all the matter is in equilibrium.
00:32:54 And then with small quantum fluctuations
00:32:57 and run it forward,
00:32:59 and then it produces, at least in broad strokes,
00:33:04 the universe we see around us today.
00:33:06 Do you think we’ll ever be able to,
00:33:09 with the tools of physics, with the way science is,
00:33:12 with the way the human mind is,
00:33:14 we’ll ever be able to get to the moment of the Big Bang
00:33:17 in our understanding or even the moment before the Big Bang?
00:33:21 Can we understand what happened before the Big Bang?
00:33:24 I’m optimistic both that we’ll be able to measure more,
00:33:31 so observe more,
00:33:33 and that we’ll be able to figure out more.
00:33:36 So they’re very, very tangible prospects
00:33:40 for observing the extremely early universe,
00:33:45 so even much earlier than we can observe now
00:33:49 through looking at gravitational waves.
00:33:52 Gravitational waves, since they interact so weakly
00:33:55 with ordinary matter,
00:33:58 sort of send a minimally processed signal from the Big Bang.
00:34:03 It’s a very weak signal
00:34:05 because it’s traveled a long way
00:34:07 and diffused over long spaces,
00:34:09 but people are gearing up to try to detect
00:34:13 gravitational waves that could have come
00:34:15 from the early universe.
00:34:16 Yeah, LIGO’s an incredible engineering project.
00:34:19 It’s the most sensitive, precise devices on Earth.
00:34:24 The fact that humans can build something like that
00:34:27 is truly awe inspiring from an engineering perspective.
00:34:31 Right, but these gravitational waves from the early universe
00:34:34 will probably be of a much longer wavelength
00:34:38 than LIGO is capable of sensing,
00:34:41 so there’s a beautiful project
00:34:44 that’s contemplated to put lasers
00:34:51 in different locations in the solar system.
00:34:54 We really, really separate it
00:34:56 by solar system scale differences,
00:34:59 like artificial planets or moons in different places
00:35:03 and see the tiny motions of those
00:35:06 relative to one another
00:35:07 as a signal of radiation from the Big Bang.
00:35:10 We can also maybe indirectly see the imprint
00:35:15 of gravitational waves from the early universe
00:35:18 on the photons, the microwave background radiation.
00:35:23 That is our present way of seeing into the earliest universe,
00:35:27 but those photons interact much more strongly with matter.
00:35:31 They’re much more strongly processed,
00:35:32 so they don’t give us directly such an unprocessed view
00:35:37 of the early universe, of the very early universe,
00:35:41 but if gravitational waves leave some imprint on that
00:35:45 as they move through, we could detect that too,
00:35:49 and people are trying, as we speak,
00:35:53 working very hard towards that goal.
00:35:56 It’s so exciting to think about a sensor
00:35:58 the size of the solar system.
00:36:01 That would be a fantastic,
00:36:03 I mean, that would be a pinnacle artifact
00:36:06 of human endeavor to me.
00:36:08 It would be such an inspiring thing
00:36:11 that just we want to know,
00:36:15 and we go to these extraordinary lengths
00:36:17 of making gigantic things that are also very sophisticated
00:36:20 because what you’re trying to do,
00:36:22 you have to understand how they move.
00:36:24 You have to understand the properties of light
00:36:28 that are being used, the interference between light,
00:36:30 and you have to be able to make the light with lasers
00:36:34 and understand the quantum theory
00:36:35 and get the timing exactly right.
00:36:38 It’s an extraordinary endeavor
00:36:40 involving all kinds of knowledge
00:36:42 from the very small to the very large,
00:36:45 and all in the service of curiosity
00:36:49 and built on a grand scale, so.
00:36:52 Yeah, it would make me proud to be a human if we did that.
00:36:58 I love that you’re inspired both by the power of theory
00:37:01 and the power of experiment.
00:37:02 So both, I think, are exceptionally impressive
00:37:07 that the human mind can come up with theories
00:37:10 that give us a peek into how the universe works,
00:37:13 but also construct tools that are way bigger
00:37:16 than the evolutionary origins we came from.
00:37:20 Right, and by the way,
00:37:22 the fact that we can design such things and they work
00:37:25 is an extraordinary demonstration
00:37:28 that we really do understand a lot.
00:37:30 And then in some ways.
00:37:33 And it’s our ability to answer questions
00:37:36 that also leads us to be able
00:37:37 to address more ambitious questions.
00:37:39 So you mentioned at the Big Bang in the early days,
00:37:45 things are pretty homogeneous.
00:37:46 Yes.
00:37:47 But here we are, sitting on Earth,
00:37:51 two hairless apes, you could say, with microphones.
00:37:57 In talking about the brief history of things,
00:37:58 you said it’s much harder to describe Sweden
00:38:00 than it is the universe.
00:38:03 So there’s a lot of complexity.
00:38:05 There was a lot of interesting details here.
00:38:07 So how does this complexity come to be, do you think?
00:38:11 It seems like there’s these pockets.
00:38:13 Yeah.
00:38:14 We don’t know how rare of like where hairless apes emerge.
00:38:18 Yeah.
00:38:19 And then that came from the initial soup
00:38:22 that was homogeneous.
00:38:23 Was that an accident?
00:38:26 Well, we understand in broad outlines
00:38:31 how it could happen.
00:38:33 We certainly don’t understand why it happened exactly
00:38:36 in the way it did.
00:38:40 Or there are certainly open questions
00:38:42 about the origins of life
00:38:44 and how inevitable the emergence of intelligence was
00:38:47 and how that happened.
00:38:48 But in the very broadest terms,
00:38:52 the universe early on was quite homogeneous,
00:38:58 but not completely homogeneous.
00:39:01 There were part in 10,000 fluctuations in density
00:39:07 within this primordial plasma.
00:39:10 And as time goes on, there’s an instability
00:39:16 which causes those density contrasts to increase.
00:39:20 There’s a gravitational instability
00:39:21 where it’s denser, the gravitational attractions
00:39:24 are stronger.
00:39:25 And so that brings in more matter
00:39:27 and it gets even denser and so on and so on.
00:39:29 So there’s a natural tendency of matter to clump
00:39:34 because of gravitational interactions.
00:39:37 And then the equation is complicated.
00:39:39 We have lots of things clumping together.
00:39:43 Then we know what the laws are,
00:39:47 but we have to a certain extent wave our hands
00:39:50 about what happens.
00:39:51 But basic understanding of chemistry
00:39:56 says that if things and the physics of radiation
00:40:00 tells us that as things start to clump together,
00:40:02 they can radiate, give off some energy.
00:40:05 So they don’t just, they slow down.
00:40:07 As a result, they lose energy.
00:40:09 They can collaborate together, cool down,
00:40:12 form things like stars, form things like planets.
00:40:16 And so in broad terms, there’s no mystery.
00:40:19 There’s, that’s what the scenario,
00:40:22 that’s what the equations tell you should happen.
00:40:25 But because it’s a process involving
00:40:30 many, many fundamental individual units,
00:40:37 the application of the laws that govern individual units
00:40:40 to these things is very delicate,
00:40:46 computationally very difficult.
00:40:48 And more profoundly, the equations have
00:40:52 this probability of chaos or sensitivity
00:40:54 to initial conditions, which tells you tiny differences
00:40:57 in the initial state can lead to enormous differences
00:41:00 in the subsequent behavior.
00:41:02 So physics, fundamental physics at some point says,
00:41:08 okay, chemists, biologists, this is your problem.
00:41:11 And then again, in broad terms,
00:41:16 we know how it’s conceivable that the humans
00:41:23 and things like that, how complex structure can emerge.
00:41:28 It’s a matter of having the right kind of temperature
00:41:34 and the right kind of stuff.
00:41:36 So you need to be able to make chemical bonds
00:41:41 that are reasonably stable
00:41:42 and be able to make complex structures.
00:41:45 And we’re very fortunate that carbon has this ability
00:41:48 to make backbones and elaborate branchings and things.
00:41:54 So you can get complex things that we call biochemistry.
00:41:57 And yet the bonds can be broken a little bit
00:42:01 with the help of energetic injections from the sun.
00:42:04 So you have to have both the possibility of changing,
00:42:07 but also the useful degree of stability.
00:42:10 And we know at that very, very broad level, physics
00:42:15 can tell you that it’s conceivable.
00:42:17 If you want to know what really happened,
00:42:23 what really can happen, then you have to work a bit,
00:42:26 go to chemistry.
00:42:27 If you want to know what actually happened,
00:42:29 then you really have to consult the fossil record
00:42:32 and biologists.
00:42:33 And so these ways of addressing the issue
00:42:41 are complimentary in a sense.
00:42:43 They use different kinds of concepts,
00:42:49 they use different languages
00:42:52 and they address different kinds of questions,
00:42:54 but they’re not inconsistent, they’re just complimentary.
00:42:59 It’s kind of interesting to think about those early fluctuations
00:43:03 as our earliest ancestors.
00:43:07 Yes, that’s right.
00:43:08 So it’s amazing to think that this is the modern answer
00:43:15 to the, or the modern version of what the Hindu philosophers
00:43:24 had, that art thou.
00:43:25 If you ask what, okay, those little quantum fluctuations
00:43:30 in the early universe are the seeds out of which complexity,
00:43:36 including plausibly humans, really evolve.
00:43:40 You don’t need anything else.
00:43:42 That brings up the question of asking for a friend here
00:43:47 if there’s other pockets of complexity,
00:43:52 commonly called as alien intelligent civilizations out there.
00:43:59 Well, we don’t know for sure,
00:44:00 but I have a strong suspicion that the answer is yes
00:44:05 because the one case we do have at hand to study
00:44:13 here on Earth, we sort of know what the conditions were
00:44:17 that were helpful to life,
00:44:18 the right kind of temperature, the right kind of star
00:44:21 that keeps, maintains that temperature for a long time,
00:44:24 the liquid environment of water.
00:44:28 And once those conditions emerged on Earth,
00:44:33 which was roughly four and a half billion years ago,
00:44:36 it wasn’t very long before what we call life
00:44:39 started to leave relics.
00:44:41 So we can find forms of life, primitive forms of life
00:44:47 that are almost as old as the Earth itself
00:44:49 in the sense that once the Earth was turned
00:44:55 from a very hot boiling thing
00:44:58 and cooled off into a solid mass with water,
00:45:02 life emerged very, very quickly.
00:45:03 So it seems that these general conditions for life
00:45:09 are enough to make it happen relatively quickly.
00:45:13 Now, the other lesson I think that one can draw
00:45:21 from this one example, it’s dangerous to draw lessons
00:45:24 from one example, but that’s all we’ve got,
00:45:27 and that the emergence of intelligent life
00:45:32 is a different issue altogether.
00:45:35 That took a long time and seems to have been
00:45:40 pretty contingent for a long time.
00:45:47 Well, for most of the history of life,
00:45:50 it was single celled things.
00:45:55 Even multicellular life only rose
00:45:58 about 600 million years ago, so much after.
00:46:01 And then intelligence is kind of a luxury.
00:46:12 Many more kinds of creatures have big stomachs
00:46:18 than big brains.
00:46:20 In fact, most have no brains at all in any reasonable sense.
00:46:25 And the dinosaurs ruled for a long, long time
00:46:30 and some of them were pretty smart,
00:46:31 but they were at best bird brains
00:46:35 because birds came from the dinosaurs.
00:46:37 And it could have stayed that way.
00:46:41 And then the emergence of humans was very contingent
00:46:46 and kind of a very, very recent development
00:46:49 on evolutionary timescales.
00:46:51 And you can argue about the level of human intelligence,
00:46:55 but I think that’s what we’re talking about.
00:46:58 It’s very impressive and can ask these kinds of questions
00:47:02 and discuss them intelligently.
00:47:07 So I guess my, so this is a long winded answer
00:47:13 or justification of my feeling
00:47:16 is that the conditions for life in some form
00:47:21 are probably satisfied many, many places
00:47:28 around the universe and even within our galaxy.
00:47:33 I’m not so sure about the emergence of intelligent life
00:47:36 or the emergence of technological civilizations.
00:47:41 That seems much more contingent and special.
00:47:47 And we might, it’s conceivable to me
00:47:50 that we’re the only example in the galaxy.
00:47:54 Although, yeah, I don’t know one way or the other.
00:47:56 I have different opinions on different days of the week.
00:47:59 But one of the things that worries me
00:48:01 in the spirit of being humble,
00:48:04 that our particular kind of intelligence
00:48:09 is not very special.
00:48:10 So there’s all kinds of different intelligences.
00:48:13 And even more broadly,
00:48:15 there could be many different kinds of life.
00:48:19 So the basic definition, and I just had,
00:48:22 I think somebody that you know, Sarah Walker,
00:48:24 I just had a very long conversation with her
00:48:27 about even just the very basic question
00:48:29 of trying to define what is life from a physics perspective.
00:48:34 Even that question within itself,
00:48:36 I think one of the most fundamental questions
00:48:38 in science and physics and everything
00:48:41 is just trying to get a hold,
00:48:43 trying to get some universal laws
00:48:45 around the ideas of what is life
00:48:47 because that kind of unlocks a bunch of things
00:48:49 around life, intelligence, consciousness,
00:48:52 all those kinds of things.
00:48:53 I agree with you in a sense,
00:48:55 but I think that’s a dangerous question
00:48:56 because the answer can’t be any more precise
00:49:01 than the question.
00:49:02 And the question, what is life,
00:49:07 kind of assumes that we have a definition of life
00:49:11 and that it’s a natural phenomena
00:49:12 that can be distinguished.
00:49:14 But really there are edge cases like viruses
00:49:17 and some people would like to say
00:49:20 that electrons have consciousness.
00:49:25 So you can’t, if you really have fuzzy concepts,
00:49:28 it’s very hard to reach precise kinds of scientific answers.
00:49:34 But I think there’s a very fruitful question
00:49:37 that’s adjacent to it,
00:49:39 which has been pursued in different forms
00:49:42 for quite a while
00:49:44 and is now becoming very sophisticated
00:49:47 in reaching in new directions.
00:49:50 And that is, what are the states of matter
00:49:53 that are possible?
00:49:55 So in high school or grade school,
00:49:58 you learn about solids, liquids and gases,
00:50:01 but that really just scratches the surface
00:50:04 of different ways that are distinguishable,
00:50:07 that matter can form into macroscopically different,
00:50:15 meaningful patterns that we call phases.
00:50:17 And then there are precise definitions
00:50:19 of what we mean by phases of matter
00:50:21 and that have been worked out fruitful over the decades.
00:50:26 And we’re discovering new states of matter all the time
00:50:29 and kind of having to work at what we mean by matter.
00:50:33 We’re discovering the capabilities of matter
00:50:35 to organize in interesting ways.
00:50:39 And some of them, like liquid crystals,
00:50:46 are important ingredients of life.
00:50:49 Our cell membranes are liquid crystals,
00:50:51 and that’s very important to the way they work.
00:50:55 Recently, there’s been a development
00:50:57 in where we’re talking about states of matter
00:51:01 that are not static, but that have dynamics,
00:51:06 that have characteristic patterns,
00:51:09 not only in space, but in time.
00:51:11 These are called time crystals,
00:51:12 and that’s been a development
00:51:14 that’s just in the last decade or so.
00:51:17 It’s just really, really flourishing.
00:51:20 And so is there a state of matter
00:51:25 or a group of states of matter that corresponds to life?
00:51:31 Maybe, but the answer can’t be any more definite
00:51:34 than the question.
00:51:35 I mean, I gotta push back on the,
00:51:38 those are just words.
00:51:39 I mean, I disagree with you.
00:51:41 The question points to a direction.
00:51:45 The answer might be able to be more precise
00:51:49 than the question, because just as you’re saying,
00:51:53 there is a, we could be discovering
00:51:56 certain characteristics and patterns
00:51:59 that are associated with a certain type of matter,
00:52:02 macroscopically speaking,
00:52:04 and that we can then be able to post facto say,
00:52:10 this is, let’s assign the word life to this kind of matter.
00:52:14 I agree with that completely, that’s what that’s,
00:52:17 but that’s, so it’s not a disagreement.
00:52:19 It’s very frequent in physics that, or in science,
00:52:23 that words that are in common use
00:52:26 get refined and reprocessed into scientific terms
00:52:31 that’s happened for things like force and energy.
00:52:35 And so we, in a way, we find out
00:52:38 what the useful definition is, or symmetry, for instance.
00:52:43 And the common usage may be quite different
00:52:47 from the scientific usage,
00:52:48 but the scientific usage is special
00:52:52 and takes on a life of its own,
00:52:53 and we find out what the useful version of it is,
00:52:59 the fruitful version of it is.
00:53:02 So I do think, so in that spirit,
00:53:05 I think if we can identify states of matter
00:53:10 or linked states of matter that can carry on processes
00:53:18 of self reproduction and development
00:53:23 and information processing,
00:53:28 we might be tempted to classify those things as life.
00:53:34 Well, can I ask you about the craziest one,
00:53:36 which is the one we know maybe least about,
00:53:41 which is consciousness.
00:53:42 Is it possible that there are certain kinds of matter
00:53:44 would be able to classify as conscious,
00:53:50 meaning like, so there’s the panpsychists, right,
00:53:54 who are the philosophers who kind of try to imply
00:53:57 that all matter has some degree of consciousness,
00:54:01 and you can almost construct like a physics of consciousness.
00:54:04 Do you, again, we’re in such early days of this,
00:54:09 but nevertheless, it seems useful to talk about it.
00:54:13 Is there some sense from a physics perspective
00:54:15 to make sense of consciousness?
00:54:18 Is there some hope?
00:54:19 Well, again, consciousness is a very imprecise word
00:54:24 and loaded with connotations that I think we should,
00:54:28 we don’t wanna start a scientific analysis with that,
00:54:31 I don’t think.
00:54:34 It’s often been important in science
00:54:38 to start with simple cases and work up.
00:54:43 Consciousness, I think what most people think of
00:54:45 when you talk about consciousness is,
00:54:47 okay, what am I doing in the world?
00:54:52 This is my experience.
00:54:53 I have a rich inner life and experience,
00:54:57 and where is that in the equations?
00:54:59 And I think that’s a great question,
00:55:02 a great, great question,
00:55:03 and actually, I think I’m gearing up to spend part of,
00:55:07 I mean, to try to address that in coming years.
00:55:10 One version of asking that question,
00:55:12 just as you said now,
00:55:14 is what is the simplest formulation of that to study?
00:55:19 I think I’m much more comfortable
00:55:20 with the idea of studying self awareness
00:55:23 as opposed to consciousness,
00:55:25 because that sort of gets rid of the mystical aura of the thing.
00:55:30 And self awareness is in simple,
00:55:33 you know, I think contiguous at least
00:55:38 with ideas about feedback.
00:55:41 So if you have a system that looks at its own state
00:55:45 and responds to it, that’s a kind of self awareness.
00:55:50 And more sophisticated versions
00:55:54 could be like in information processing things,
00:55:57 computers that look into their own internal state
00:56:00 and do something about it.
00:56:03 And I think that could also be done in neural nets.
00:56:08 This is called recurrent neural nets,
00:56:10 which are hard to understand and kind of a frontier.
00:56:15 So I think understanding those
00:56:18 and gradually building up a kind of profound ability
00:56:26 to conceptualize different levels of self awareness.
00:56:32 What do you have to not know?
00:56:33 And what do you have to know?
00:56:34 And when do you know that you don’t know it?
00:56:36 Or when do you, what do you think you know
00:56:38 that you don’t really know?
00:56:39 And these, I think clarifying those issues,
00:56:44 when we clarify those issues
00:56:47 and get a rich theory around self awareness,
00:56:51 I think that will illuminate the questions
00:56:55 about consciousness in a way that, you know,
00:56:58 scratching your chin and talking about qualia
00:57:00 and blah, blah, blah, blah is never gonna do.
00:57:04 Well, I also have a different approach to the whole thing.
00:57:06 So there’s, from a robotics perspective,
00:57:09 you can engineer things that exhibit qualities
00:57:13 of consciousness without understanding how things work.
00:57:19 And from that perspective, you, it’s like a back door,
00:57:25 like enter through the psychology door.
00:57:28 Precisely, I think we’re on the same wavelength here.
00:57:32 I think that, and let me just add one comment,
00:57:35 which is I think we should try to understand consciousness
00:57:40 as we experience it as, in evolutionary terms,
00:57:48 and ask ourselves, why, why does it happen?
00:57:53 This thing seems useful.
00:57:54 Why is it useful?
00:57:55 Why is it useful?
00:57:56 Interesting question.
00:57:57 I think we’ve got a conscious eyewatch here.
00:58:01 Interesting question.
00:58:02 Thank you, Siri.
00:58:03 Okay.
00:58:08 I’ll get back to you later.
00:58:09 The, and I think what we’re gonna,
00:58:14 I’m morally certain that what’s gonna emerge
00:58:18 from analyzing recurrent neural nets
00:58:21 and robotic design and advanced computer design
00:58:26 is that having this kind of looking at the internal state
00:58:33 in a structured way that doesn’t look at everything,
00:58:38 this guy’s has, it’s encapsulated,
00:58:40 looks at highly processed information,
00:58:42 is very selective and makes choices
00:58:44 without knowing how they’re made.
00:58:45 There’s, there’ll also be an unconscious.
00:58:47 I think that that is gonna be,
00:58:49 turn out to be really essential
00:58:51 to doing efficient information processing.
00:58:55 And that’s why it evolved,
00:58:59 because it’s, it’s, it’s, it’s helpful in,
00:59:03 because brains come at a high cost.
00:59:06 So there has to be, there has to be a good why.
00:59:09 And there’s a reason, yeah.
00:59:10 They’re rare in evolution and big brains
00:59:16 are rare in evolution and they, they come at a big cost.
00:59:19 You mean, if you, you, they, they,
00:59:22 they have high metabolic demands.
00:59:27 They require, you know, very active lifestyle,
00:59:30 warm bloodedness and take, take away from the ability
00:59:36 to support metabolism of digestion.
00:59:39 And so, so it’s, it’s, it comes at a high cost.
00:59:42 It has to, it has to pay back.
00:59:44 Yeah, I think it has a lot of value in social interaction.
00:59:47 So I actually am spending the rest of the day today
00:59:49 and with our friends that are,
00:59:54 our legged friends in robotic form at Boston Dynamics.
00:59:58 And I think, so my probably biggest passion
01:00:03 is human robot interaction.
01:00:05 And it seems that consciousness from the perspective
01:00:09 of the robot is very useful to improve
01:00:12 the human robot interaction experience.
01:00:16 The first, the display of consciousness,
01:00:18 but then to me, there’s a gray area
01:00:20 between the display of consciousness and consciousness itself.
01:00:23 If you think of consciousness
01:00:24 from an evolutionary perspective,
01:00:26 it seems like a useful tool in human communication, so.
01:00:29 Yes, it’s certainly, well,
01:00:32 whatever consciousness is will turn out to be.
01:00:35 I think addressing it through its use
01:00:39 and working up from simple cases
01:00:42 and also working up from engineering experience
01:00:45 in trying to do efficient computation,
01:00:48 including efficient management of social interactions
01:00:53 is going to really shed light on these questions.
01:00:56 As I said, in a way that sort of musing abstractly
01:00:59 about consciousness never would.
01:01:01 So as I mentioned, I talked to Sarah Walker
01:01:04 and first of all, she says, hi, spoke very highly of you.
01:01:07 One of her concerns about physics and physicists and humans
01:01:12 is that we may not fully understand the system
01:01:16 that we’re inside of.
01:01:18 Meaning like, there may be limits
01:01:22 to the kind of physics we do
01:01:24 in trying to understand the system of which we’re part of.
01:01:28 So like, the observer is also the observed.
01:01:33 In that sense, it seems like
01:01:39 our tools of understanding the world,
01:01:42 I mean, this is mostly centered around the questions
01:01:44 of what is life, trying to understand the patterns
01:01:47 that are characteristic of life and intelligence,
01:01:51 all those kinds of things.
01:01:53 We’re not using the right tools because we’re in the system.
01:01:57 Is there something that resonates with you there?
01:02:01 Almost like…
01:02:02 Well, yes, we have limitations, of course,
01:02:08 in the amount of information we can process.
01:02:12 On the other hand, we can get help from our Silicon friends
01:02:16 and we can get help from all kinds of instruments
01:02:21 that make up for our perceptual deficits.
01:02:25 And we can use, at a conceptual level,
01:02:30 we can use different kinds of concepts
01:02:32 to address different kinds of questions.
01:02:35 So I’m not sure exactly what problem she’s talking about.
01:02:40 It’s a problem akin to an organism living in a 2D plane
01:02:45 trying to understand a three dimensional world.
01:02:47 Well, we can do that.
01:02:48 I mean, in fact, for practical purposes,
01:02:53 most of our experience is two dimensional.
01:02:55 It’s hard to move vertically.
01:02:57 And yet we’ve produced conceptually
01:03:00 a three dimensional symmetry
01:03:01 and in fact, four dimensional space time.
01:03:05 So by thinking in appropriate ways and using instruments
01:03:10 and getting consistent accounts and rich accounts,
01:03:14 we find out what concepts are necessary.
01:03:22 And I don’t see any end in sight of the process
01:03:25 or any showstoppers because, let me give you an example.
01:03:32 I mean, for instance, QCD,
01:03:35 our theory of the strong interaction,
01:03:37 has nice equations, which I helped to discover.
01:03:40 What’s QCD?
01:03:41 Quantum chromodynamics.
01:03:42 So it’s our theory of the strong interaction,
01:03:47 the interaction that is responsible for nuclear physics.
01:03:51 So it’s the interaction that governs
01:03:53 how quarks and gluons interact with each other
01:03:55 and make protons and neutrons
01:03:59 and all the strong, the related particles
01:04:03 and many things in physics.
01:04:05 It’s one of the four basic forces of nature
01:04:07 as we presently understand it.
01:04:09 And so we have beautiful equations,
01:04:15 which we can test in very special circumstances
01:04:22 using at high energies, at accelerators.
01:04:25 So we’re certain that these equations are correct.
01:04:28 Prizes are given for it and so on.
01:04:30 And people try to knock it down and they can’t.
01:04:32 Yeah, but the situations in which we can calculate
01:04:43 the consequences of these equations are very limited.
01:04:46 So for instance, no one has been able to demonstrate
01:04:52 that this theory, which is built on quarks and gluons,
01:04:58 which no one, which you don’t observe,
01:05:01 actually produces protons and neutrons
01:05:03 and the things you do observe.
01:05:04 This is called the problem of confinement.
01:05:07 So no one’s been able to prove that analytically
01:05:11 in a way that a human can understand.
01:05:13 On the other hand, we can take these equations
01:05:16 to a computer, to gigantic computers and compute.
01:05:20 And by God, you get the world from it.
01:05:25 So these equations in a way that we don’t understand
01:05:32 in terms of human concepts, we can’t do the calculations,
01:05:36 but our machines can do them.
01:05:39 So with the help of what I like to call our silicon friends
01:05:43 and their descendants in the future,
01:05:46 we can understand in a different way
01:05:50 that allows us to understand more.
01:05:53 But I don’t think we’ll ever, no human is ever going
01:05:56 to be able to solve those equations in the same way.
01:06:00 So, but I think that’s, you know,
01:06:04 when we find limitations to our natural abilities,
01:06:09 we can try to find workarounds.
01:06:12 And sometimes that’s appropriate concepts.
01:06:15 Sometimes it’s appropriate instruments.
01:06:17 Sometimes it’s a combination of the two.
01:06:19 But I think it’s premature to get defeatist about it.
01:06:26 I don’t see any logical contradiction
01:06:32 or paradox or limitation
01:06:35 that will bring this process to a halt.
01:06:38 Well, I think the idea is to continue thinking
01:06:40 outside the box in different directions,
01:06:42 meaning just like how the math allows us
01:06:45 to think in multiple dimensions
01:06:47 outside of our perception system, sort of thinking,
01:06:54 you know, coming up with new tools
01:06:55 of mathematics or computation or all those kinds of things
01:06:58 to take different perspectives on our universe.
01:07:04 Well, I’m all for that.
01:07:05 You know, and I kind of have even elevated into a principle
01:07:08 which is of complementarity following Bohr
01:07:11 that you need different ways of thinking
01:07:16 even about the same things
01:07:18 in order to do justice to their reality
01:07:21 and answer different kinds of questions about them.
01:07:23 I mean, we’ve several times alluded to the fact
01:07:27 that human beings are hard to understand
01:07:30 and the concepts that you use to understand human beings
01:07:34 if you wanna prescribe drugs for them
01:07:37 or see what’s gonna happen if they move very fast
01:07:42 or are exposed to radiation.
01:07:45 And so that requires one kind of thinking
01:07:47 that’s very physical based on the fact
01:07:52 that the materials that were made out of.
01:07:55 On the other hand, if you want to understand
01:07:57 how a person’s going to behave
01:07:59 in a different kind of situation,
01:08:02 you need entirely different concepts from psychology
01:08:06 and there’s nothing wrong with that.
01:08:08 You can have very different ways
01:08:09 of addressing the same material
01:08:11 that are useful for different purposes, right?
01:08:14 Can you describe this idea
01:08:16 which is fascinating of complementarity a little bit?
01:08:18 Sort of first of all, what state is the principle?
01:08:25 What is it?
01:08:26 And second of all, what are good examples
01:08:29 starting from quantum mechanics?
01:08:30 You used to mention psychology.
01:08:32 Let’s talk about this more.
01:08:33 It’s like in your new book
01:08:34 one of the most fascinating ideas actually.
01:08:38 I think it’s a wonderful, yeah.
01:08:40 To me it’s, well, it’s the culminating chapter of the book
01:08:43 and I think since the whole book is about the big lessons
01:08:48 or big takeaways from profound understanding
01:08:52 of the physical world that we’ve achieved,
01:08:56 including that it’s mysterious in some ways,
01:09:01 this was the final overarching lesson, complementarity.
01:09:06 Lesson, complementarity and it’s a approach.
01:09:16 So unlike some of these other things
01:09:18 which are just facts about the world,
01:09:20 like the world is both big and small
01:09:22 and different sizes and is big but we’re not small,
01:09:26 things we talked about earlier
01:09:28 and the fact that the universe is comprehensible
01:09:30 and how complexity could emerge from simplicity
01:09:33 and so those things are in the broad sense
01:09:37 facts about the world.
01:09:39 Complementarity is more an attitude towards the world
01:09:42 than encouraged by the facts about the world.
01:09:46 And it’s the concept or the approach
01:09:54 or the realization that it can be appropriate
01:09:59 and useful and inevitable and unavoidable
01:10:02 to use very different descriptions of the same object
01:10:08 or the same system or the same situation
01:10:12 to answer different kinds of questions
01:10:15 that may be very different
01:10:17 and even mutually uninterpretable,
01:10:22 immutually incomprehensible.
01:10:27 But both correct somehow.
01:10:28 But both correct and sources of different kinds of insight
01:10:32 which is so weird.
01:10:34 But it seems to work in so many cases.
01:10:36 It works in many cases and I think it’s a deep fact
01:10:41 about the world and how we should approach it.
01:10:44 It’s most rigorous form where it’s actually a theorem
01:10:50 if quantum mechanics is correct,
01:10:53 occurs in quantum mechanics
01:10:55 where the primary description of the world
01:11:00 is in terms of wave functions.
01:11:03 But let’s not talk about the world.
01:11:04 Let’s just talk about a particle, an electron.
01:11:09 The primary description of that electron
01:11:12 is its wave function.
01:11:14 And the wave function can be used to predict
01:11:19 where it’s gonna be.
01:11:21 If you observe, it’ll be in different places
01:11:24 with different probabilities or how fast it’s moving.
01:11:27 And it’ll also be moving in different ways
01:11:31 with different probabilities.
01:11:32 That’s what quantum mechanics says.
01:11:35 And you can predict either set of probabilities
01:11:38 if you know what’s gonna happen
01:11:40 if I make an observation of the position or the velocity.
01:11:48 So the wave function gives you ways of doing both of those.
01:11:51 But to do it, to get those predictions,
01:11:54 you have to process the wave function in different ways.
01:11:57 You process it one way for position
01:11:59 and in a different way for momentum.
01:12:01 And those ways are mathematically incompatible.
01:12:05 It’s like you have a stone
01:12:08 and you can sculpt it into a Venus de Milo
01:12:11 or you can sculpt it into David, but you can’t do both.
01:12:18 And that’s an example of complementarity.
01:12:20 To answer different kinds of questions,
01:12:22 you have to analyze the system in different ways
01:12:25 that are mutually incompatible,
01:12:29 but both valid to answer different kinds of questions.
01:12:32 So in that case, it’s a theorem,
01:12:34 but I think it’s a much more widespread phenomena
01:12:38 that applies to many cases
01:12:40 where we can’t prove it as a theorem,
01:12:42 but it’s a piece of wisdom, if you like,
01:12:46 and appears to be a very important insight.
01:12:53 And if you ignore it,
01:12:53 you can get very confused and misguided.
01:13:02 Do you think this is a useful hack
01:13:06 for ideas that we don’t fully understand?
01:13:10 Or is this somehow a fundamental property
01:13:13 of all or many ideas,
01:13:16 that you can take multiple perspectives
01:13:19 and they’re both true?
01:13:20 Well, I think it’s both.
01:13:24 So it’s both the answer to all questions.
01:13:26 Yes, that’s right.
01:13:27 It’s not either or, it’s both.
01:13:28 It’s paralyzing to think that we live in a world
01:13:32 that’s fundamentally surrounded by complementary ideas.
01:13:39 Because we somehow want to attach ourselves
01:13:44 to absolute truths,
01:13:45 and absolute truths certainly don’t like the idea
01:13:48 of complementarity.
01:13:50 Yes, Einstein was very uncomfortable with complementarity.
01:13:53 And in a broad sense,
01:13:55 the famous Bohr Einstein debates
01:13:59 revolved around this question
01:14:00 of whether the complementarity
01:14:03 that is a foundational feature of quantum mechanics,
01:14:08 as we have it,
01:14:10 is a permanent feature of the universe
01:14:16 and our description of nature.
01:14:19 And so far, quantum mechanics wins.
01:14:22 And it’s gone from triumph to triumph.
01:14:26 Whether complementarity is rock bottom,
01:14:28 I guess, you can never be sure.
01:14:31 I mean, but it looks awfully good
01:14:34 and it’s been very successful.
01:14:35 And certainly, complementarity has been extremely useful
01:14:40 and fruitful in that domain,
01:14:43 including some of Einstein’s attempts to challenge it
01:14:50 with the famous Einstein Podolsky Rosen experiment
01:14:55 turned out to be confirmations
01:14:57 that have been useful in themselves.
01:15:03 But so thinking about these things was fruitful,
01:15:05 but not in the way that Einstein hoped.
01:15:07 Yeah, so as I said, in the case of quantum mechanics
01:15:19 and this dilemma or dichotomy
01:15:26 between processing the wave function in different ways,
01:15:29 it’s a theorem.
01:15:30 They’re mutually incompatible
01:15:31 and the physical correlate of that
01:15:32 is the Heisenberg uncertainty principle
01:15:35 you can’t have position and momentum determined at once.
01:15:41 But in other cases, like one that I like to think about
01:15:48 or like to point out as an example
01:15:50 is free will and determinism.
01:15:52 It’s much less of a theorem
01:15:57 and more a kind of way of thinking about things
01:16:06 that I think is reassuring
01:16:10 and avoids a lot of unnecessary quarreling and confusion.
01:16:16 The quarreling I’m okay with
01:16:17 and the confusion I’m okay with,
01:16:18 I mean, people debate about difficult ideas,
01:16:21 but the question is whether it could be
01:16:24 almost a fundamental truth.
01:16:26 I think it is a fundamental truth.
01:16:28 That free will is both an illusion and not.
01:16:32 Yes, I think that’s correct.
01:16:35 There’s a reason why people say quantum mechanics is weird
01:16:39 and complementarity is a big part of that.
01:16:45 To say that our actual whole world is weird,
01:16:48 the whole hierarchy of the universe is weird
01:16:52 in this kind of particular way,
01:16:54 and it’s quite profound, but it’s also humbling
01:17:03 because it’s like we’re never going to be on sturdy ground
01:17:06 in the way that humans like to be.
01:17:09 It’s like you have to embrace that this whole thing
01:17:13 is like unsteady mess.
01:17:18 It’s one of many lessons in humility
01:17:21 that we run into in profound understanding of the world.
01:17:28 The Copernican revolution was one,
01:17:30 that the earth is not the center of the universe.
01:17:35 Darwinian evolution is another,
01:17:36 that humans are not the pinnacle of God’s creation and the apparent result
01:17:53 of deep understanding of physical reality,
01:17:57 that mind emerges from matter and there’s no call
01:18:05 on special life forces or souls.
01:18:09 These are all lessons in humility,
01:18:11 and I actually find complementarity a liberating concept.
01:18:19 It’s, okay, you know, we…
01:18:21 Yeah, it is in a way.
01:18:22 That is what I remember.
01:18:28 There’s a story about Dr. Johnson,
01:18:30 and he’s talking with Boswell,
01:18:32 and Boswell was, they were discussing a sermon
01:18:36 that they’d both heard,
01:18:37 and the sort of culmination of the sermon was the speaker saying,
01:18:43 I accept the universe.
01:18:45 And Dr. Johnson said, well, damn well better.
01:18:50 And there’s a certain joy in accepting the universe
01:18:55 because it’s mind expanding.
01:18:57 And to me, complementarity also suggests tolerance,
01:19:10 suggests opportunities for understanding things
01:19:15 in different ways that add to rather than detract
01:19:22 from understanding.
01:19:25 So I think it’s an opportunity for mind expansion
01:19:29 and demanding that there’s only one way
01:19:33 to think about things can be very limiting.
01:19:36 On the free will one, that’s a trippy one, though.
01:19:38 To think like I am the decider of my own actions
01:19:43 and at the same time I’m not is tricky to think about,
01:19:49 but there does seem to be some kind of profound truth in that.
01:19:53 I get, well, I think it is tied up.
01:19:56 It will turn out to be tied up when we understand things better
01:20:00 with these issues of self awareness and where we get,
01:20:04 what we perceive as making choices,
01:20:06 what does that really mean and what’s going on under the hood.
01:20:12 But I’m speculating about a future understanding
01:20:15 that’s not in place at present.
01:20:17 Your sense there will always be,
01:20:19 like as you dig into the self awareness thing,
01:20:22 there’ll always be some places
01:20:24 where complementarity is gonna show up.
01:20:26 Oh, definitely, yeah.
01:20:28 I mean, there will be, how should I say?
01:20:31 There’ll be kind of a God’s eye view
01:20:33 which sees everything that’s going on
01:20:37 in the computer or the brain.
01:20:40 And then there’s the brain’s own view
01:20:42 or the central processor or whatever it is,
01:20:46 what we call the self, the consciousness,
01:20:50 that’s only aware of a very small part of it.
01:20:53 And those are very different.
01:20:54 Those are, so the God’s eye view can be deterministic
01:20:59 while the self view sees free will.
01:21:07 I’m pretty sure that’s how it’s gonna work out actually.
01:21:11 But as it stands, free will is a concept
01:21:15 that we definitely, at least I feel I definitely experience,
01:21:19 I can choose to do one thing then another.
01:21:21 And other people I think are sufficiently similar to me
01:21:24 that I trust that they feel the same way.
01:21:30 And it’s an essential concept in psychology
01:21:33 and law and so forth.
01:21:35 But at the same time, I think that mind emerges from matter
01:21:42 and that there’s an alternative description of matter
01:21:47 that’s up to subtleties about quantum mechanics,
01:21:51 which I don’t think are relevant here,
01:21:53 really is deterministic.
01:21:56 Let me ask you about some particles.
01:21:57 Okay.
01:21:59 First the absurd question,
01:22:00 almost like a question that like Plato would ask.
01:22:04 What is the smallest thing in the universe?
01:22:08 As far as we know, the fundamental particles
01:22:13 out of which we build our most successful description
01:22:17 of nature are points.
01:22:20 They don’t have any internal structure.
01:22:27 So that’s as small as can be.
01:22:31 So what does that mean operationally?
01:22:34 That means that they obey equations that describe entities
01:22:39 that are singular concentrations of energy,
01:22:46 momentum, angular momentum,
01:22:47 the things that particles have,
01:22:50 but localized at individual points.
01:22:53 Now that mathematical structure
01:22:57 is only revealed partially in the world
01:23:01 because to process the wave function
01:23:04 in a way that accesses information about the precise
01:23:09 position of things, you have to apply a lot of energy
01:23:12 and that’s an idealization
01:23:14 and you can apply infinite amount of energy
01:23:16 to determine a precise position.
01:23:19 But at the mathematical level,
01:23:23 we build the world out of particles that are points.
01:23:26 So do they actually exist and what are we talking about?
01:23:29 Oh, they exist.
01:23:30 So let me ask sort of do quarks exist?
01:23:33 Yes, do electrons exist?
01:23:36 Yes, do photons exist?
01:23:37 Yes.
01:23:38 But what does it mean for them to exist?
01:23:39 Okay, so well, the hard answer to that,
01:23:43 the precise answer is that we construct the world
01:23:49 out of equations that contain entities
01:23:51 that are reproducible,
01:23:56 that exist in vast numbers throughout the universe,
01:24:00 that have definite properties of mass,
01:24:05 spin and a few others that we call electrons
01:24:13 and what an electron is is defined by the equations
01:24:17 that it satisfies theoretically
01:24:19 and we find that there are many, many exemplars
01:24:24 of that entity in the physical world.
01:24:28 So in the case of electrons,
01:24:31 we can isolate them and study them
01:24:34 and individual ones in great detail
01:24:36 and we can check that they all actually are identical
01:24:42 and that’s why chemistry works and yes.
01:24:45 So in that case, it’s very tangible.
01:24:49 Similarly with photons,
01:24:51 you can study them individually, the units of light
01:24:55 and nowadays, it’s very practical
01:24:59 to study individual photons
01:25:01 and determine their spin and their other basic properties
01:25:05 and check out the equations in great detail.
01:25:11 For quarks and gluons,
01:25:13 which are the other two main ingredients
01:25:16 of our model of matter that’s so successful,
01:25:22 it’s a little more complicated
01:25:23 because the quarks and gluons that appear in our equations
01:25:29 don’t appear directly as particles you can isolate
01:25:33 and study individually.
01:25:35 They always occur within what are called bound states
01:25:41 or structures like protons.
01:25:43 A proton, roughly speaking, is composed of three quarks
01:25:48 and a lot of gluons but we can detect them
01:25:50 in a remarkably direct way actually nowadays,
01:25:54 whereas at relatively low energies,
01:25:58 the behavior of quarks is complicated.
01:26:00 At high energies, they can propagate through space
01:26:05 relatively freely for a while and we can see their tracks.
01:26:11 So ultimately, they get recaptured into protons
01:26:14 and other mesons and funny things
01:26:17 but for a short time, they propagate freely
01:26:21 and while that happens, we can take snapshots
01:26:25 and see their manifestations.
01:26:29 Actually, this kind of thing is exactly
01:26:31 what I got the Nobel Prize for,
01:26:33 predicting that this would work.
01:26:35 And similarly for gluons,
01:26:36 although you can’t isolate them as individual particles
01:26:41 and study them in the same way that we study electrons,
01:26:43 say, you can use them theoretically as entities
01:26:51 out of which you build tangible things
01:26:57 that we actually do observe
01:26:59 but also you can, at accelerators at high energy,
01:27:03 you can liberate them for brief periods of time
01:27:06 and study and get convincing evidence
01:27:10 that they leave tracks and you can get convincing evidence
01:27:15 that they were there and have the properties
01:27:17 that we wanted them to have.
01:27:19 Can we talk about asymptotic freedom,
01:27:21 this very idea that you won the Nobel Prize for?
01:27:24 Yeah.
01:27:25 So it describes a very weird effect to me,
01:27:30 the weird in the following way.
01:27:33 So the way I think of most forces or interactions,
01:27:38 the closer you are, the stronger the effect,
01:27:43 the stronger the force, right?
01:27:46 With quarks, the close they are,
01:27:50 the less so the strong interaction.
01:27:53 And in fact, they’re basically act like free particles
01:27:58 when they’re very close.
01:28:00 That’s right, yes.
01:28:01 But this requires a huge amount of energy.
01:28:04 Like can you describe me why, how does this even work?
01:28:11 How weird it is?
01:28:12 A proper description must bring in quantum mechanics
01:28:18 and relativity and it’s,
01:28:21 so a proper description and equations,
01:28:25 so a proper description really is probably more
01:28:29 than we have time for and require quite a bit of patience
01:28:34 on your part, but.
01:28:35 How does relativity come into play?
01:28:37 Wait, wait a minute.
01:28:39 Relativity is important because when we talk about
01:28:48 trying to think about short distances,
01:28:51 we have to think about very large momenta
01:28:55 and very large momenta are connected
01:28:56 to very large energy in relativity.
01:28:59 And so the connection between how things behave
01:29:02 at short distances and how things behave at high energy
01:29:06 really is connected through relativity
01:29:09 in sort of a slightly backhanded way.
01:29:13 Quantum mechanics indicates that short,
01:29:16 to get to analyze short distances,
01:29:20 you need to bring in probes that carry a lot of momentum.
01:29:26 This again is related to uncertainty
01:29:29 because it’s the fact that you have to bring in
01:29:31 a lot of momentum that interferes with the possibility
01:29:36 of determining position and momentum at the same time.
01:29:40 If you want to determine position,
01:29:41 you have to use instruments that bring in a lot of momentum.
01:29:45 And because of that, those same instruments
01:29:48 can’t also measure momentum
01:29:50 because they’re disturbing the momentum that,
01:29:53 and then the momentum brings in energy and yeah.
01:29:56 So that there’s also the effect that asymptotic freedom
01:29:59 comes from the possibility of spontaneously making
01:30:08 quarks and gluons for short amounts of time
01:30:12 that fluctuate into existence and out of existence.
01:30:16 And the fact that that can be done
01:30:21 with a very little amount of energy
01:30:23 and uncertainty and energy translates
01:30:26 into uncertainty and time.
01:30:27 So if you do that for a short time, you can do that.
01:30:31 Well, it’s all comes in a package.
01:30:35 So I told you it would take a while to really explain,
01:30:39 but the results can be understood.
01:30:44 I mean, we can state the results pretty simply, I think.
01:30:48 So in everyday life, we do encounter some forces
01:30:53 that increase with distance
01:30:56 and kind of turn off at short distances.
01:30:59 That’s the way rubber bands work, if you think about it,
01:31:02 or if you pull them hard, they resist,
01:31:06 but they get flabby if the rubber band is not pulled.
01:31:12 And so there are, that can happen in the physical world,
01:31:17 but what’s really difficult is to see
01:31:19 how that could be a fundamental force
01:31:21 that’s consistent with everything else we know.
01:31:24 And that’s what asymptotic freedom is.
01:31:28 It says that there’s a very particular kind
01:31:33 of fundamental force that involves special particles
01:31:37 called gluons with very special properties
01:31:40 that enables that kind of behavior.
01:31:43 So there were experiment, at the time we did our work,
01:31:47 there were experimental indications
01:31:49 that quarks and gluons did have this kind of property,
01:31:54 but there were no equations
01:31:56 that were capable of capturing it.
01:31:59 And we found the equations and showed how they work
01:32:02 and showed how they, that they were basically unique.
01:32:06 And this led to a complete theory
01:32:08 of how the strong interaction works,
01:32:09 which is the quantum chromodynamics we mentioned earlier.
01:32:14 And so that’s the phenomenon that quarks and gluons
01:32:23 interact very, very weakly when they’re close together.
01:32:26 That’s connected through relativity
01:32:29 with the fact that they also interact very, very weakly
01:32:32 at high energies.
01:32:34 So if you have, so at high energies,
01:32:37 the simplicity of the fundamental interaction gets revealed.
01:32:42 At the time we did our work,
01:32:43 the clues were very subtle,
01:32:46 but nowadays at what are now high energy accelerators,
01:32:50 it’s all obvious.
01:32:51 So we would have had a much,
01:32:52 well, somebody would have had a much easier time
01:32:55 20 years later, looking at the data,
01:32:57 you can sort of see the quarks and gluons.
01:32:59 As I mentioned, they leave these short tracks
01:33:02 that would have been much, much easier,
01:33:04 but from fundamental, from indirect clues,
01:33:08 we were able to piece together enough
01:33:10 to make that behavior a prediction
01:33:13 rather than a post diction, right?
01:33:15 So it becomes obvious at high energies.
01:33:17 It becomes very obvious.
01:33:19 When we first did this work,
01:33:21 it was frontiers of high energy physics
01:33:24 and at big international conferences,
01:33:27 there would always be sessions on testing QCD
01:33:30 and whether this proposed description
01:33:34 of the strong interaction was in fact correct and so forth.
01:33:37 And it was very exciting.
01:33:39 But nowadays the same kind of work,
01:33:44 but much more precise with calculations
01:33:48 to more accuracy and experiments
01:33:50 that are much more precise
01:33:54 and comparisons that are very precise.
01:33:57 Now it’s called calculating backgrounds
01:33:59 because people take this for granted
01:34:03 and wanna see deviations from the theory,
01:34:06 which would be the new discoveries.
01:34:09 Yeah, the cutting edge becomes a foundation
01:34:11 and the foundation becomes boring.
01:34:13 Yes.
01:34:15 Is there some, for basic explanation purposes,
01:34:19 is there something to be said about strong interactions
01:34:23 in the context of the strong nuclear force
01:34:26 for the attraction between protons and neutrons
01:34:30 versus the interaction between quarks within protons?
01:34:35 Well, quarks and gluons have the same relation
01:34:40 basically to nuclear physics
01:34:43 as electrons and photons have
01:34:46 to atomic and molecular physics.
01:34:49 So atoms and photons are the dynamic entities
01:34:56 that really come into play in chemistry and atomic physics.
01:35:01 Of course, you have to have the atomic nuclei,
01:35:03 but those are small and relatively inert,
01:35:07 really the dynamical part.
01:35:09 And for most purposes of chemistry,
01:35:12 you just say that you have this tiny little nucleus,
01:35:14 which QCD gives you.
01:35:17 Don’t worry about it.
01:35:17 It just, it’s there.
01:35:19 The real action is the electrons moving around
01:35:22 and exchanging and things like that.
01:35:26 Okay, but we want it to understand the nucleus too.
01:35:29 And so atoms are sort of quantum mechanical clouds
01:35:36 of electrons held together by electrical forces,
01:35:38 which is photons.
01:35:39 And then this radiation,
01:35:40 which is another aspect of photons.
01:35:43 That’s where all the fun happens
01:35:44 is the electrons and the photons.
01:35:45 Yeah, that’s right.
01:35:47 And the nucleus are kind of the,
01:35:51 well, they give the positive charge
01:35:53 and most of the mass of matter,
01:35:55 but they don’t, since they’re so heavy,
01:36:01 they don’t move very much in chemistry.
01:36:03 And I’m oversimplifying drastically.
01:36:07 They’re not contributing much to the interaction in chemistry.
01:36:12 For most purposes in chemistry,
01:36:13 you can just idealize them as concentrations
01:36:16 of positive mass and charge that are,
01:36:20 you don’t have to look inside,
01:36:22 but people are curious what’s inside.
01:36:24 And that was a big thing on the agenda
01:36:29 of 20th century physics starting in the 19,
01:36:32 well, starting with the 20th century
01:36:34 and unfolding throughout of trying to understand
01:36:38 what forces held the atomic nucleus together,
01:36:41 what it was and so.
01:36:44 Anyway, the story that emerges from QCD
01:36:49 is that very similar to the way that,
01:36:55 well, broadly similar to the way
01:36:57 that clouds of electrons held together
01:37:01 by electrical forces give you atoms
01:37:04 and ultimately molecules.
01:37:08 Protons and neutrons are like atoms
01:37:13 made now out of quarks, quark clouds held together
01:37:17 by gluons, which are like the photons
01:37:20 that give the electric forces,
01:37:23 but this is giving a different force, the strong force.
01:37:26 And the residual forces between protons and neutrons
01:37:31 that are leftover from the basic binding
01:37:37 are like the residual forces between atoms
01:37:40 that give molecules, but in the case of protons and neutrons,
01:37:43 it gives you atomic nuclei.
01:37:45 So again, for definitional purposes,
01:37:48 QCD, quantum chromodynamics,
01:37:51 is basically the physics of strong interaction.
01:37:54 Yeah, we understand, we now would understand,
01:37:56 I think most physicists would say
01:37:58 it’s the theory of quarks and gluons
01:38:02 and how they interact.
01:38:04 But it’s a very precise, and I think it’s fair to say,
01:38:07 very beautiful theory based on mathematical symmetry
01:38:11 of a high order, and another thing that’s beautiful
01:38:16 about it is that it’s kind of
01:38:22 in the same family as electrodynamics.
01:38:26 The conceptual structure of the equations are very similar.
01:38:31 They’re based on having particles that respond to charge
01:38:34 in a very symmetric way.
01:38:37 In the case of electrodynamics,
01:38:39 it’s photons that respond to electric charge.
01:38:42 In the case of quantum chromodynamics,
01:38:44 there are three kinds of charge that we call colors,
01:38:47 but they’re nothing like colors.
01:38:49 They really are like different kinds of charge.
01:38:51 But they rhyme with the same kind of,
01:38:54 like it’s similar kind of dynamics.
01:38:56 Similar kind of dynamics.
01:38:57 I’d like to say that QCD is like QED on steroids.
01:39:02 And instead of one photon, you have eight gluons.
01:39:05 Instead of one charge, you have three color charges.
01:39:09 But there’s a strong family resemblance between them.
01:39:13 But the context in which QCD does this thing
01:39:16 is it’s much higher energies.
01:39:19 Like that’s where it comes to life.
01:39:20 Well, it’s a stronger force,
01:39:22 so that to access how it works and kind of pry things apart,
01:39:28 you have to inject more energy.
01:39:30 And so that gives us, in some sense,
01:39:35 a hint of how things were in the earlier universe.
01:39:39 Yeah, well, in that regard,
01:39:41 asymptotic freedom is a tremendous blessing
01:39:43 because it means things get simpler at high energy.
01:39:48 The universe was born free.
01:39:50 Born free.
01:39:50 That’s very good, yes.
01:39:52 Universe was born.
01:39:53 So in atomic physics,
01:39:56 a similar thing happens in the theory of stars.
01:39:59 Stars are hot enough that the interactions
01:40:03 between electrons and photons, they’re liberated.
01:40:07 They don’t form atoms anymore.
01:40:08 They make a plasma,
01:40:09 which in some ways is simpler to understand.
01:40:12 You don’t have complicated chemistry.
01:40:14 And in the early universe, according to QCD,
01:40:18 similarly atomic nuclei dissolved
01:40:20 and take the constituent quarks and gluons,
01:40:22 which are moving around very fast
01:40:24 and interacting in relatively simple ways.
01:40:27 And so this opened up the early universe
01:40:30 to scientific calculation.
01:40:33 Can I ask you about some other weird particles
01:40:35 that make up our universe?
01:40:37 What are axions?
01:40:39 And what is the strong CP problem?
01:40:42 Okay, so let me start with what the strong CP problem is.
01:40:49 First of all, well, C is charge conjugation,
01:40:53 which is the transformation,
01:40:57 the notional transformation, if you like,
01:40:59 that changes all particles into their antiparticles.
01:41:03 And the concept of C symmetry,
01:41:09 charge conjugation symmetry, is that if you do that,
01:41:13 you find the same laws that would work.
01:41:16 So the laws are symmetric if the behavior
01:41:20 that particles exhibit is the same
01:41:22 as the behavior you get with all their antiparticles.
01:41:27 And then P is parity,
01:41:31 which is also called spatial inversion.
01:41:35 It’s basically looking at a mirror universe
01:41:39 and saying that the laws that are obeyed
01:41:41 in a mirror universe, when you look,
01:41:44 that the mirror images obey the same laws
01:41:46 as the sources of their images.
01:41:50 There’s no way of telling left from right, for instance,
01:41:52 that the laws don’t distinguish between left and right.
01:41:55 Now, in the mid 20th century,
01:42:00 people discovered that both of those are not quite true.
01:42:05 Really, the equation that the mirror universe,
01:42:08 the universe that you see in a mirror
01:42:15 is not gonna obey the same laws
01:42:18 as the universe that we actually interpret.
01:42:23 You would be able to tell
01:42:26 if you did the right kind of experiments,
01:42:28 which was the mirror and which was the real thing.
01:42:33 Anyway, that.
01:42:34 That’s the parity and they show
01:42:36 that the parity doesn’t necessarily hold.
01:42:37 It doesn’t quite hold.
01:42:41 Examining what the exceptions are turned out to be,
01:42:45 to lead to all kinds of insight
01:42:47 about the nature of fundamental interactions,
01:42:49 especially properties of neutrinos
01:42:51 and the weak interaction, it’s a long story.
01:42:53 But it’s a very, it’s a.
01:42:55 So you just define the C and the P,
01:42:57 the conjugation, the charge conjugation.
01:42:59 Now that I’ve done that, I wanna.
01:43:00 What’s the problem?
01:43:01 Shove them off.
01:43:02 Okay, great.
01:43:04 Because it’s easier to talk about T,
01:43:06 which is time reversal symmetry.
01:43:08 We have very good reasons to think CPT
01:43:13 is an accurate symmetry of nature.
01:43:17 It’s on the same level as relativity
01:43:19 and quantum mechanics, basically.
01:43:20 So that better be true.
01:43:23 Or else we.
01:43:24 So it’s symmetric when you.
01:43:26 When you do.
01:43:26 When you do conjugation parity and time.
01:43:28 And time and space reversal.
01:43:30 If you do all three,
01:43:32 then you get the same physical consequences.
01:43:35 Now, so, but that means that CP is equivalent to T.
01:43:39 But what’s observed in the world
01:43:41 is that T is not quite an accurate symmetry of nature,
01:43:45 either.
01:43:46 So most phenomena of, at the fundamental level.
01:43:52 So interactions among elementary particles
01:43:54 and the basic gravitational interaction.
01:43:59 If you ran them backwards in time,
01:44:03 you’d get the same laws.
01:44:05 So if, again, going back.
01:44:08 This time we don’t talk about a mirror,
01:44:11 but we talk about a movie.
01:44:13 If you take a movie and then run it backwards,
01:44:18 that’s the time reversal.
01:44:21 It’s good to think about a mirror in time.
01:44:23 Yeah, it’s like a mirror in time.
01:44:25 If you run the movie backwards,
01:44:29 it would look very strange
01:44:30 if you were looking at complicated objects
01:44:32 and a Charlie Chaplin movie or whatever.
01:44:37 It would look very strange if you ran it backwards in time.
01:44:40 But at the level of basic interactions,
01:44:43 if you were able to look at the atoms
01:44:46 and the quarks involved, they would obey the same laws.
01:44:49 They do a very good approximation, but not exactly.
01:44:53 So this is not exactly, that means you could tell.
01:44:55 You could tell, but you’d have to do very, very
01:44:59 subtle experiments with at high energy accelerators
01:45:04 to take a movie that looked different
01:45:06 when you ran it backwards.
01:45:08 This was a discovery by two great physicists
01:45:13 named Jim Cronin and Val Fitch in the mid 1960s.
01:45:20 Previous to that, over all the centuries
01:45:22 of development of physics with all its precise laws,
01:45:25 they did seem to have this gratuitous property
01:45:30 that they look the same if you run the equations backwards.
01:45:33 It’s kind of an embarrassing property actually
01:45:35 because life isn’t like that.
01:45:38 So empirical reality does not have this imagery
01:45:41 in any obvious way.
01:45:42 And yet the laws did.
01:45:44 It’s almost like the laws of physics
01:45:46 are missing something fundamental about life
01:45:48 if it holds that property, right?
01:45:51 Well, that’s the embarrassing nature of it.
01:45:54 Yeah, it’s embarrassing.
01:45:55 Well, people worked hard at what’s,
01:46:01 this is a problem that’s thought to belong
01:46:04 to the foundations of statistical mechanics
01:46:07 or the foundations of thermodynamics
01:46:10 to understand how behavior,
01:46:14 which is grossly not symmetric
01:46:18 with respect to reversing the direction of time
01:46:21 in large objects, how that can emerge from equations
01:46:24 which are symmetric with respect to changing
01:46:28 the direction of time to a very good approximation.
01:46:31 And that’s still an interesting endeavor.
01:46:33 That’s interesting.
01:46:35 And actually it’s an exciting frontier of physics now
01:46:38 to sort of explore the boundary
01:46:40 between when that’s true and when it’s not true.
01:46:42 When you get to smaller objects
01:46:44 and exceptions like time crystals.
01:46:47 I definitely have to ask you about time crystals
01:46:49 in a second here.
01:46:50 But so the CP problem and T,
01:46:53 so there’s all of these.
01:46:55 We’re in danger of infinite regress,
01:46:57 but we have to convert soon.
01:46:59 So.
01:47:00 Can’t possibly be turtles all the way down.
01:47:02 We’re gonna get to the bottom turtle.
01:47:03 So it became,
01:47:06 so it got to be a real,
01:47:08 I mean, it’s a really puzzling thing
01:47:11 why the laws should have this very odd property
01:47:15 that we don’t need.
01:47:16 And in fact, it’s kind of an embarrassment
01:47:20 in addressing empirical reality.
01:47:22 But it seemed to be almost,
01:47:24 it seemed to be exactly true for a long time.
01:47:26 And then almost true.
01:47:29 And in way, almost true is even,
01:47:33 is more disturbing than exactly true
01:47:35 because exactly true,
01:47:37 it could have been just a fundamental feature of the world.
01:47:39 And at some level you just have to take it as it is.
01:47:42 And if it’s a beautiful, easily articulatable regularity,
01:47:47 you could say that, okay,
01:47:48 that’s fine as a fundamental law of nature.
01:47:51 But to say that it’s approximately true,
01:47:53 but not exactly, that’s weird.
01:47:56 So, and then, so there was great progress
01:48:00 in the late part of the 20th century
01:48:06 in getting to an understanding
01:48:09 of fundamental interactions in general
01:48:11 that shed light on this issue.
01:48:14 It turns out that the basic principles of relativity
01:48:20 and quantum mechanics,
01:48:22 plus the kind of high degree of symmetry that we found,
01:48:27 the so called gauge symmetry
01:48:28 that characterizes the fundamental interactions,
01:48:31 when you put all that together,
01:48:33 it’s a very, very constraining framework.
01:48:37 And it has some indirect consequences
01:48:42 because the possible interactions are so constrained.
01:48:45 And one of the indirect consequences
01:48:48 is that the possibilities for violating the symmetry
01:48:54 between forwards and backwards in time are very limited.
01:48:57 They’re basically only two.
01:49:01 And one of them occurs and leads to a very rich theory
01:49:05 that explains the Cronin Fish experiment
01:49:07 and a lot of things that have been done subsequently
01:49:09 has been used to make all kinds of successful predictions.
01:49:13 So that’s turned out to be a very rich interaction.
01:49:19 It’s esoteric and the effects only show up at accelerators
01:49:23 and are small and so on,
01:49:24 but they might’ve been very important in the early universe
01:49:26 and lead to them be connected to the asymmetry
01:49:29 between matter and antimatter in the present universe.
01:49:32 And so, but that’s another digression.
01:49:36 The point is that that was fine.
01:49:40 That was a triumph to say
01:49:41 that there was one possible kind of interaction
01:49:44 that would violate time reversal symmetry.
01:49:47 And sure enough, there it is.
01:49:49 But the other kind doesn’t occur.
01:49:54 So we still got a problem.
01:49:55 Why doesn’t it occur?
01:49:59 So we’re close to really finally understanding
01:50:01 this profound gratuitous feature of the world
01:50:04 that is almost but not quite symmetric
01:50:08 under reversing the direction of time, but not quite there.
01:50:12 And to understand that last bit
01:50:18 is a challenging frontier of physics today.
01:50:22 And we have a promising proposal for how it works,
01:50:27 which is a kind of theory of evolution.
01:50:31 So there’s this possible interaction,
01:50:35 which we call a coupling,
01:50:37 and there’s a numerical quantity
01:50:39 that tells us how strong that is.
01:50:41 And traditionally in physics,
01:50:43 we think of these kinds of numerical quantities
01:50:46 as constants of nature that you just have to put them in.
01:50:54 From experiment, they have a certain value and that’s it.
01:50:57 And who am I to question what God doing?
01:51:01 They’re just constant.
01:51:02 Well, they seem to be just constants.
01:51:04 I’m just wondering.
01:51:06 But in this case,
01:51:10 it’s been fruitful to think and work out a theory
01:51:15 where that strength of interaction
01:51:22 is actually not a constant.
01:51:23 It’s a fun, it’s a field.
01:51:27 It’s a, fields are the fundamental ingredients
01:51:31 of modern physics.
01:51:32 Like there’s an electron field,
01:51:34 there’s a photon field,
01:51:35 which is also called the electromagnetic field.
01:51:37 And so all of these particles
01:51:39 are manifestations of different fields.
01:51:41 And there could be a field,
01:51:45 something that depends on space and time.
01:51:47 So a dynamical entity instead of just a constant here.
01:51:53 And if you do things in a nice way,
01:51:57 that’s very symmetric,
01:51:58 very much suggested aesthetically by the theory.
01:52:02 But the theory we do have,
01:52:05 then you find that you get a field
01:52:11 which as it evolves from the early universe,
01:52:17 settles down to a value
01:52:22 that’s just right to make the laws
01:52:27 very nearly exact, invariant or symmetric
01:52:32 with respect to reversal of time.
01:52:33 It might appear as a constant,
01:52:34 but it’s actually a field that evolved over time.
01:52:36 It evolved over time, okay.
01:52:38 But when you examine this proposal in detail,
01:52:42 you find that it hasn’t quite settled down to exactly zero.
01:52:47 There it’s still,
01:52:48 the field is still moving around a little bit.
01:52:52 And because the motion is so,
01:52:55 the motion is so difficult.
01:52:59 The material is so rigid.
01:53:00 And this material,
01:53:01 the field that fills all space is so rigid.
01:53:03 Even small amounts of motion can involve lots of energy.
01:53:08 And that energy takes the form of particles,
01:53:14 fields that are in motion
01:53:16 are always associated with particles.
01:53:18 And those are the axioms.
01:53:20 And if you calculate how much energy
01:53:23 is in these residual oscillations,
01:53:26 this axiom gas that fills all the universe,
01:53:30 if this fundamental theory is correct,
01:53:32 you get just the right amount
01:53:36 to make the dark matter that astronomers want.
01:53:39 And it has just the right properties.
01:53:41 So I’d love to believe that.
01:53:44 So that might be a thing that unlocks,
01:53:47 might be the key to understanding dark matter.
01:53:50 Yeah, I’d like to think so.
01:53:51 And many, many physicists are coming around
01:53:53 to this point of view,
01:53:54 which I’ve been a voice in the wilderness.
01:53:58 I was a voice in the wilderness for a long time,
01:54:00 but now it’s become very popular, maybe even dominant.
01:54:04 So almost like,
01:54:05 so this axion particle slash field
01:54:10 would be the thing that explains dark matter.
01:54:13 It explains, yeah,
01:54:14 would solve this fundamental question of finally,
01:54:17 of why the laws are almost, but not quite exactly the same
01:54:24 if you run them backwards in time.
01:54:26 And then seemingly in a totally different
01:54:30 conceptual universe,
01:54:32 it would also provide,
01:54:35 give us an understanding of the dark matter.
01:54:38 That’s not what it was designed for.
01:54:41 And the theory wasn’t proposed with that in mind,
01:54:45 but when you work out the equations, that’s what you get.
01:54:47 That’s always a good sign.
01:54:49 Yes.
01:54:51 I think I vaguely read somewhere
01:54:53 that there may be early experimental validation of axion.
01:54:59 Is that, am I reading the wrong?
01:55:03 Well, there’ve been quite a few false alarms
01:55:05 and I think there are some of them still,
01:55:08 people desperately wanna find this thing.
01:55:10 And, but I don’t think any of them are convincing
01:55:15 at this point,
01:55:16 but there are very ambitious experiments
01:55:20 and kind of new,
01:55:23 you have to design new kinds of antennas
01:55:24 that are capable of detecting these predicted particles.
01:55:28 And it’s very difficult.
01:55:29 They interact very, very weakly.
01:55:31 If it were easy, it would have been done already.
01:55:33 But I think there’s good hope
01:55:37 that we can get down to the required sensitivity
01:55:40 and actually test whether these ideas are right
01:55:44 in coming years or maybe decades.
01:55:47 And then understand one of the big mysteries,
01:55:50 like literally big in terms of its fraction
01:55:53 of the universe is dark matter.
01:55:55 Yes.
01:55:56 Let me ask you about, you mentioned a few times,
01:55:59 time crystals.
01:56:01 What are they?
01:56:02 These things are, it’s a very beautiful idea
01:56:05 when we start to treat space and time
01:56:10 as similar frameworks.
01:56:13 Yes, right.
01:56:14 Physical phenomena.
01:56:15 Right, that’s what motivated it.
01:56:17 First of all, what are crystals?
01:56:19 Yeah.
01:56:20 And what are time crystals?
01:56:20 Okay, so crystals are orderly arrangements
01:56:24 of atoms in space.
01:56:27 And many materials,
01:56:30 if you cool them down gently, will form crystals.
01:56:38 And so we say that that’s a state of matter
01:56:43 that forms spontaneously.
01:56:45 And an important feature of that state of matter
01:56:50 is that the end result, the crystal,
01:56:53 has less symmetry than the equations
01:57:01 that give rise to the crystal.
01:57:03 So the equations, the basic equations of physics
01:57:09 are the same if you move a little bit.
01:57:12 So you can move, they’re homogeneous,
01:57:15 but crystals aren’t.
01:57:16 The atoms are in particular place,
01:57:18 so they have less symmetry.
01:57:20 And time crystals are the same thing in time, basically.
01:57:27 But of course, so it’s not positions of atoms,
01:57:30 but it’s orderly behavior that certain states of matter
01:57:38 will arrange themselves into spontaneously
01:57:41 if you treat them gently
01:57:44 and let them do what they want to do.
01:57:46 But repeat in that same way indefinitely.
01:57:50 That’s the crystalline form.
01:57:51 You can also have time liquids,
01:57:54 or you can have all kinds of other states of matter.
01:57:57 You can also have space time crystals
01:57:58 where the pattern only repeats if with each step of time,
01:58:03 you also move at a certain direction in space.
01:58:07 So yeah, basically it’s states of matter
01:58:12 that displace structure in time spontaneously.
01:58:17 So here’s the difference.
01:58:21 When it happens in time,
01:58:24 it sure looks a lot like it’s motion,
01:58:27 and if it repeats indefinitely,
01:58:29 it sure looks a lot like perpetual motion.
01:58:32 Yeah.
01:58:32 Like looks like free lunch.
01:58:35 And I was told that there’s no such thing as free lunch.
01:58:39 Does this violate laws of thermodynamics?
01:58:42 No, but it requires a critical examination
01:58:45 of the laws of thermodynamics.
01:58:47 I mean, let me say on background
01:58:49 that the laws of thermodynamics
01:58:51 are not fundamental laws of physics.
01:58:55 There are things we prove
01:58:58 under certain circumstances emerge
01:59:01 from the fundamental laws of physics.
01:59:03 They’re not, we don’t posit them separately.
01:59:06 They’re meant to be deduced,
01:59:08 and they can be deduced under limited circumstances,
01:59:10 but not necessarily universally.
01:59:12 And we’re finding some of the subtleties
01:59:15 and sort of accept edge cases
01:59:18 where they don’t apply in a straightforward way.
01:59:22 And this is one.
01:59:25 So time crystals do obey,
01:59:27 do have this structure in time,
01:59:30 but it’s not a free lunch
01:59:31 because although in a sense, things are moving,
01:59:36 they’re already doing what they want to do.
01:59:39 They’re in the,
01:59:40 so if you want to extract energy from it,
01:59:44 you’re gonna be foiled
01:59:44 because there’s no spare energy there.
01:59:50 So you can add energy to it and kind of disturb it,
01:59:53 but you can’t extract energy from this motion
01:59:58 because it’s gonna, it wants to do,
02:00:00 that’s the lowest energy configuration that there is,
02:00:03 so you can’t get further energy out of it.
02:00:06 So in theory, I guess perpetual motion,
02:00:10 you would be able to extract energy from it
02:00:13 if such a thing was to be created,
02:00:15 you can then milk it for energy.
02:00:17 Well, what’s usually meant
02:00:20 in the literature of perpetual motion
02:00:23 is a kind of macroscopic motion
02:00:27 that you could extract energy from
02:00:29 and somehow it would crank back up.
02:00:33 That’s not the case here.
02:00:35 If you want to extract energy,
02:00:38 this motion is not something you can extract energy from.
02:00:42 If you intervene in the behavior,
02:00:45 you can change it, but only by injecting energy,
02:00:48 not by taking away energy.
02:00:51 You mentioned that a theory of everything
02:00:54 may be quite difficult to come by.
02:00:56 A theory of everything broadly defined
02:00:58 meaning like truly a theory of everything,
02:01:00 but let’s look at a more narrow theory of everything,
02:01:03 which is the way it’s used often in physics
02:01:07 is a theory that unifies our current laws of physics,
02:01:16 general relativity, quantum field theory.
02:01:19 Do you have thoughts on this dream
02:01:22 of a theory of everything in physics?
02:01:25 How close are we?
02:01:26 Is there any promising ideas out there in your view?
02:01:29 Well, it would be nice to have.
02:01:32 It would be aesthetically pleasing.
02:01:35 Will it be useful?
02:01:36 No, probably not.
02:01:38 Well, I shouldn’t, it’s dangerous to say that,
02:01:43 but probably not.
02:01:45 I think we, certainly not in the foreseeable future.
02:01:52 Maybe to understand black holes.
02:01:54 Yeah, but that’s, yes, maybe to understand black holes,
02:01:57 but that’s not useful.
02:02:00 That’s my book.
02:02:02 And well, not only, I mean,
02:02:04 to understand it’s worse,
02:02:08 it’s not useful in the sense
02:02:09 that we’re not gonna be basing any technology anytime soon
02:02:12 on black holes, but it’s more severe than that,
02:02:16 I would say it’s that the kinds of questions
02:02:19 about black holes that we can’t answer
02:02:24 within the framework of existing theory
02:02:28 are ones that are not going to be susceptible
02:02:33 to astronomical observation in the foreseeable future.
02:02:37 They’re questions about very, very small black holes
02:02:41 when quantum effects come into play
02:02:46 so that black holes are,
02:02:50 not black holes, they’re emitting this discovery
02:02:54 of Hawking called Hawking radiation,
02:02:57 which for astronomical black holes is a tiny, tiny effect
02:03:01 that no one has ever observed, it’s a prediction
02:03:03 that’s never been checked.
02:03:04 So like supermassive black holes, that doesn’t apply?
02:03:06 No, no, the predicted rate of radiation
02:03:11 from those black holes is so tiny
02:03:13 that it’s absolutely unobservable
02:03:15 and is overwhelmed by all kinds of other effects.
02:03:21 So it’s not practical in the sense of technology,
02:03:24 it’s not even practical in the sense
02:03:26 of application to astronomy, our existing theory
02:03:33 of general relativity and quantum theory
02:03:37 and our theory of the different fundamental forces
02:03:41 is perfectly adequate to all problems of technology,
02:03:46 of technology, for sure, and almost all problems
02:03:58 of astrophysics and cosmology that appear
02:04:03 except with the notable exception
02:04:06 of the extremely early universe, if you want to ask,
02:04:09 what happened before the Big Bang
02:04:11 or what happened right at the Big Bang,
02:04:13 which would be a great thing to understand, of course.
02:04:17 Yes. We don’t, but.
02:04:19 But what about the engineering question?
02:04:21 So if we look at space travel,
02:04:23 so I think you’ve spoken with him, Eric Weinstein.
02:04:28 Oh, yeah. Really, you know,
02:04:31 he says things like we want to get off this planet.
02:04:36 His intuition is almost motivated
02:04:39 for the engineering project of space exploration
02:04:42 in order for us to crack this problem
02:04:44 of becoming a multi planetary species,
02:04:47 we have to solve the physics problem.
02:04:49 His intuition is like, if we figure out this,
02:04:51 what he calls the source code, which is like,
02:04:55 like a theory of everything might give us clues
02:05:00 on how to start hacking the fabric of reality,
02:05:04 like getting shortcuts, right?
02:05:06 It might. I can’t say that, you know,
02:05:08 I can’t say that it won’t,
02:05:10 but I can say that in the 1970s and early 1980s,
02:05:16 we achieved huge steps in understanding matter.
02:05:23 QCD, much better understanding of the weak interaction,
02:05:28 much better understanding of quantum mechanics in general.
02:05:32 And it’s had minimal impact on technology.
02:05:36 On rocket design, on propulsion.
02:05:38 On rocket design, on anything, any technology whatsoever.
02:05:42 And now we’re talking about much more esoteric things.
02:05:46 And since I don’t know what they are,
02:05:48 I can’t say for sure that they won’t affect technology,
02:05:51 but I’m very, very skeptical
02:05:52 that they would affect technology.
02:05:57 Because, you know, to access them,
02:05:59 you need very exotic circumstances
02:06:02 to make new kinds of particles with high energy.
02:06:04 You need accelerators that are very expensive
02:06:07 and you don’t produce many of them, and so forth.
02:06:09 You know, it’s just, it’s a pipe dream, I think.
02:06:13 Yeah, about space exploration.
02:06:15 I’m not sure exactly what he has in mind,
02:06:18 but to me, it’s more a problem of,
02:06:26 I don’t know, something between biology and…
02:06:29 And information processing.
02:06:34 Processing, what you mean, how should I…
02:06:37 I think human bodies are not well adapted to space.
02:06:43 Even Mars, which is the closest thing
02:06:46 to a kind of human environment
02:06:49 that we’re gonna find anywhere close by.
02:06:52 Very, very difficult to maintain humans on Mars.
02:06:57 And it’s gonna be very expensive and very unstable.
02:07:02 But I think, however, if we take a broader view
02:07:09 of what it means to bring human civilization
02:07:17 outside of the Earth, if we’re satisfied
02:07:20 with sending mines out there that we can converse with
02:07:25 and actuators that we can manipulate
02:07:29 and sensors that we can get feedback from,
02:07:33 I think that’s where it’s at.
02:07:37 And I think that’s so much more realistic.
02:07:41 And I think that’s the long term future
02:07:45 of space exploration.
02:07:48 It’s not hauling human bodies all over the place.
02:07:50 That’s just silly.
02:07:54 It’s possible that human bodies…
02:07:56 So like you said, it’s a biology problem.
02:07:59 What’s possible is that we extend human life span
02:08:03 in some way, we have to look at a bigger picture.
02:08:07 It could be just like you’re saying,
02:08:09 by sending robots with actuators
02:08:12 and kind of extending our limbs.
02:08:16 But it could also be extending some aspect of our minds,
02:08:19 some information, all those kinds of things.
02:08:20 And it could be cyborgs, it could be, it could be…
02:08:23 No, we’re talking, not getting the fun.
02:08:26 It could be, you know, it could be human brains
02:08:32 or cells that realize something
02:08:34 like human brain architecture
02:08:36 within artificial environments,
02:08:42 you know, shells, if you like,
02:08:44 that are more adapted to the conditions of space.
02:08:47 And that, yeah, so that’s entirely man machine hybrids,
02:08:52 as well as sort of remote outposts
02:08:57 that we can communicate with.
02:08:59 I think those will happen.
02:09:02 Yeah, to me, there’s some sense in which,
02:09:05 as opposed to understanding the physics
02:09:07 of the fundamental fabric of the universe,
02:09:15 I think getting to the physics of life,
02:09:17 the physics of intelligence,
02:09:18 the physics of consciousness will,
02:09:20 the physics of information that brings,
02:09:27 from which life emerges,
02:09:29 that will allow us to do space exploration.
02:09:32 Yeah, well, I think physics in the larger sense
02:09:34 has a lot to contribute here.
02:09:36 Not the physics of finding fundamental new laws
02:09:39 in the sense of another quark or axions even.
02:09:44 But physics in the sense of,
02:09:51 physics has a lot of experience
02:09:53 in analyzing complex situations
02:09:56 and analyzing new states of matter
02:09:58 and devising new kinds of instruments
02:10:00 that do clever things.
02:10:01 Physics in that sense has enormous amounts
02:10:05 to contribute to this kind of endeavor.
02:10:09 But I don’t think that looking
02:10:13 for a so called theory of everything
02:10:16 has much to do with it at all.
02:10:19 What advice would you give to a young person today
02:10:24 with a bit of fire in their eyes,
02:10:26 high school student, college student,
02:10:28 thinking about what to do with their life,
02:10:30 maybe advice about career or bigger advice
02:10:35 about life in general?
02:10:37 Well, first read fundamentals
02:10:38 because there I’ve tried to give some coherent deep advice.
02:10:45 That’s fundamentals, 10 keys to reality by Frank Kulczyk.
02:10:50 So that’s a good place to start.
02:10:50 Available everywhere.
02:10:52 If you wanna learn what I can tell you.
02:10:56 Is there an audio book?
02:10:57 I read that ebook.
02:10:58 Yes, there is an audio book.
02:10:59 There’s an audio book, that’s awesome.
02:11:00 I think it’s, I can give three pieces of wise advice
02:11:05 that I think are generally applicable.
02:11:08 One is to cast a wide net,
02:11:13 to really look around and see what looks promising,
02:11:19 what catches your imagination and promising.
02:11:25 Yeah, and those, you have to balance those two things.
02:11:28 You could have things that catch your imagination,
02:11:30 but don’t look promising in the sense
02:11:32 that the questions aren’t ripe or,
02:11:34 and things that you,
02:11:37 and part of what makes things attractive is that,
02:11:42 whether you thought you liked them or not,
02:11:43 is if you can see that there’s ferment
02:11:45 and new ideas coming up that become,
02:11:47 that’s attractive in itself.
02:11:49 So when I started out, I thought I was,
02:11:52 and when I was an undergraduate,
02:11:53 I intended to study philosophy
02:11:55 or questions of how mind emerges from matter.
02:11:57 But I thought that that wasn’t really right.
02:12:00 Timing isn’t right yet.
02:12:01 The right, the timing wasn’t right
02:12:03 for the kind of mathematical thinking
02:12:05 and conceptualization that I really enjoy and am good at.
02:12:12 But, so that’s one thing, cast a wide net, look around.
02:12:18 And that’s a pretty easy thing to do today
02:12:25 because of the internet.
02:12:27 You can look at all kinds of things.
02:12:30 You have to be careful though
02:12:30 because there’s a lot of crap also.
02:12:33 But you can sort of tell the difference
02:12:36 if you do a little digging.
02:12:42 So don’t settle on just,
02:12:44 what your thesis advisor tells you to do
02:12:46 or what your teacher tells you to do.
02:12:49 Look for yourself and get a sense of what seems promising,
02:12:54 not what seemed promising 10 years ago or, so that’s one.
02:13:03 Another thing is to, is kind of complimentary to that.
02:13:09 Well, they’re all complimentary.
02:13:12 Complimentary to that is to read history
02:13:18 and read the masters,
02:13:19 the history of ideas and masters of ideas.
02:13:22 I’d benefited enormously from, as early in my career,
02:13:28 from reading in physics, Einstein in the original
02:13:34 and Feynman’s lectures as they were coming out and Darwin.
02:13:39 You know, these, you can learn what it, and Galileo,
02:13:43 you can learn what it is to wrestle with difficult ideas
02:13:46 and how great minds did that.
02:13:48 You can learn a lot about style,
02:13:51 how to write your ideas up and express them in clear ways.
02:13:57 And also just a couple of that with,
02:14:00 I also enjoy reading biographies.
02:14:02 And biographies, yes, similarly, right, yeah.
02:14:04 So it gives you the context of the human being
02:14:08 that created those ideas.
02:14:08 Right, and brings it down to earth in the sense that,
02:14:11 you know, it was really human beings who did this.
02:14:14 It’s not, and they made mistakes.
02:14:17 And yeah, I also got inspiration from Bertrand Russell
02:14:22 who was a big hero and H.G. Wells and yeah.
02:14:25 So read the masters, make contact with great minds.
02:14:31 And when you are sort of narrowing down on a subject,
02:14:33 learn about the history of the subject
02:14:35 because that really puts in context
02:14:38 what you’re trying to do and also gives a sense of community
02:14:43 and grandeur to the whole enterprise.
02:14:46 And then the third piece of advice
02:14:48 is complimentary to both those,
02:14:51 which is sort of to get the basics under control
02:14:58 as soon as possible.
02:15:00 So if you wanna do theoretical work in science,
02:15:04 you know, you have to learn calculus,
02:15:08 multivariable calculus, complex variables, group theory.
02:15:11 Nowadays, you have to be highly computer literate
02:15:15 if you want to do experimental work.
02:15:16 You also have to be computer literate
02:15:17 and you have to learn about electronics
02:15:19 and optics and instruments.
02:15:22 So get that under control as soon as possible
02:15:26 because it’s like learning a language to produce great works
02:15:32 and express yourself fluently and with confidence.
02:15:37 It should be your native language.
02:15:39 These things should be like your native language.
02:15:41 So you’re not wondering what is the derivative?
02:15:44 This is just part of your, it’s in your bones,
02:15:50 so to speak, and the sooner that you can do that,
02:15:53 then the better.
02:15:55 So all those things can be done in parallel and should be.
02:16:01 You’ve accomplished some incredible things in your life,
02:16:04 but the sad thing about this thing we have is it ends.
02:16:09 Do you think about your mortality?
02:16:15 Are you afraid of death?
02:16:19 Well, afraid is the wrong word.
02:16:20 I mean, I wish it weren’t going to happen
02:16:23 and I’d like to, but.
02:16:27 Do you think about it?
02:16:28 I, you know, occasionally I think about,
02:16:30 well, I think about it very operationally
02:16:32 in the sense that there’s always a trade off
02:16:35 between exploration and exploitation.
02:16:39 This is a classic subject in computer science,
02:16:42 actually in machine learning that when you’re
02:16:46 in an unusual circumstance, you want to explore
02:16:50 to see what the landscape is and what, and gather data.
02:16:54 But then at some point you want to use that,
02:16:57 make, decide, make choices and say,
02:17:00 this is what I’m going to do and exploit the knowledge
02:17:02 you’ve accumulated.
02:17:03 And the longer the period of exploitation you anticipate,
02:17:10 the more exploration you should do in new directions.
02:17:14 And so for me, I’ve had to sort of adjust the balance
02:17:18 of exploration and exploitation and.
02:17:25 That’s it, you’ve explored quite a lot.
02:17:28 Yeah, well, I haven’t shut off the exploitation at all.
02:17:31 I’m still hoping for. The exploration.
02:17:34 The exploration, right.
02:17:35 I’m still hoping for 10 or 15 years
02:17:38 of top flight performance.
02:17:39 But the, several years ago now when I was 50 years old,
02:17:47 I was at the Institute for Advanced Study
02:17:49 and my office was right under Freeman Dyson’s office
02:17:52 and we were kind of friendly.
02:17:53 And, you know, he found out it was my 50th birthday
02:17:58 and said, congratulations.
02:18:00 And you should feel liberated because no one expects much
02:18:05 of a 50 year old theoretical physicist.
02:18:07 And he, and he obviously had felt liberated
02:18:10 by reaching a certain age.
02:18:13 And yeah, there is something to that.
02:18:15 I feel, you know, I feel I don’t have to catch,
02:18:19 I don’t have to keep in touch
02:18:21 with the latest hypertechnical developments
02:18:25 in particle physics or string theory or something.
02:18:27 I, because I’m not gonna, I’m really not gonna
02:18:31 be exploiting that.
02:18:33 But I, but where I am exploring in these directions
02:18:37 of machine learning and things like that.
02:18:40 And, but then, but I’m also concentrating
02:18:43 within physics on exploiting directions
02:18:46 that I’ve already established
02:18:48 and the laws that we already have
02:18:50 and doing things like,
02:18:52 I’m very actively involved in trying to design,
02:18:58 helping people, experimentalists and engineers even
02:19:02 to design antennas that are capable of detecting axions.
02:19:08 So there, and that’s, there we’re deep
02:19:10 in the exploitation stage.
02:19:13 It’s not a matter of finding the new laws,
02:19:14 but of really, you know, using the laws we have
02:19:17 to kind of finish the story off.
02:19:20 So it’s complicated, but I’m, you know,
02:19:25 I’m very happy with my life right now
02:19:27 and I’m enjoying it and I don’t wanna cloud that
02:19:31 by thinking too much that it’s gonna come to an end.
02:19:39 You know, it’s a gift I didn’t earn.
02:19:42 Is there a good thing to say about
02:19:45 why this gift that you’ve gotten
02:19:50 and didn’t deserve is so damn enjoyable?
02:19:53 So like, what’s the meaning of this thing, of life?
02:19:57 To me, interacting with people I love, my family,
02:20:01 and I have a very wide circle of friends now
02:20:04 and I’m trying to produce some institutions
02:20:08 that will survive me as well as my work
02:20:12 and it’s just, it’s, how should I say?
02:20:18 It’s a positive feedback loop when you do something
02:20:24 and people appreciate it and then you wanna do more
02:20:28 and you get rewarded and it’s just, how should I say?
02:20:32 This is another gift that I didn’t earn
02:20:34 and don’t understand, but I have a dopamine system
02:20:37 and yeah, I’m happy to use it.
02:20:42 It seems to get energized by the creative process,
02:20:47 by the process of exploration.
02:20:48 Very much so.
02:20:49 And all of that started from the little fluctuations
02:20:56 shortly after the Big Bang.
02:20:58 Frank, well, whatever those initial conditions
02:21:01 and fluctuations did that created you, I’m glad they did.
02:21:04 This is, thank you for all the work you’ve done,
02:21:07 for the many people you’ve inspired,
02:21:09 for the many, of the billion, most of your ideas
02:21:12 were pretty useless of the several billions,
02:21:16 as it is for all humans, but you had quite a few
02:21:20 truly special ideas and thank you for bringing those
02:21:23 to the world and thank you for wasting your valuable time
02:21:25 with me today, it’s truly an honor.
02:21:27 It’s been a joy and I hope people enjoy it
02:21:31 and I think the kind of mind expansion that I’ve enjoyed
02:21:37 by interacting with physical reality at this deep level,
02:21:41 I think can be conveyed to and enjoyed by many, many people
02:21:45 and that’s one of my missions in life, to share it.
02:21:48 Beautiful.
02:21:49 Thanks for listening to this conversation
02:21:50 with Frank Wilczek and thank you to The Information,
02:21:54 NatSuite, ExpressVPN, Blinkist and 8sleep.
02:21:58 Check them out in the description to support this podcast
02:22:01 and now let me leave you with some words
02:22:03 from Albert Einstein, nothing happens until something moves.
02:22:08 Thanks for listening and hope to see you next time.