The Philosophy of Physics with Elise Crull

0:00Chuck, why is it every time we have a show that goes to the frontier of science, you need an edible? Uh, because that is how I cope with science. Some people don't need to cope with science. I need to cope with science. And so... The frontier of philosophy, quantum physics, and physics. Coming right up. Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk. Neil deGrasse Tyson, your personal astrophysicist. I got Chuck Nice with me. Chuck it, baby. Hey, what's happening, Neil? All right. Love it when I look over and I see you there.

0:47Oh, you know, the feeling's mutual. Oh, thank you. It's almost like I'm looking at myself. So, we're doing something we haven't yet done on this show. All right. We're going to do the philosophy of physics. What? I know. That's why we haven't done it. And we had somebody right up the street. In the hood. Actually, literally in the hood, up in Harlem. And this is Elise, can I pronounce your last name? Kroll. Kroll. Elise Kroll. Elise Kroll. Welcome to StarTalk. Hey, thanks for having me. Yeah, so you're a professor of philosophy in the philosophy department. That's right, yep. This is a CUNY. Yep.

1:23And you authored a book just last year, came out, but it was like a very serious academic tome, The Einstein Paradox. This is a very seductive title, okay? Einstein paradox, the debate on non-locality and incompleteness, oh, come on. Oh, in 1935. So the title actually comes from Schrodinger. He had a folder in his archives. Schrodinger. Schrodinger. Of cat fame. Of cat fame. And in fact, the cat was born in this correspondence with Einstein that he had labeled in German, the Einstein paradox. And so we translated those letters into English, many of them for the first time, and it's all the famous physicists talking to one another about what this physics is.

2:08So why can't regular people read this? They sure can. It's just that the primary literature in particular, just reading the way that Einstein and Schrodinger and Heisenberg and Bohr talked to one another. They had their own language. Wow. Yeah, okay. They did, and they had their own - Like twins. They just have their own thing. Like twins that get their own language. Except in this case, their own language was often German. Oh, okay. In some cases, Danish. Danish would be for Neil Bohr. That's right, that's right. But they all had a really nuanced stance. Like they had different ideas about what was problematic about quantum mechanics.

2:45Interesting, because quantum mechanics is just being born at that time. It's about 10 years in at this point. Yeah, and what precipitated this was Einstein, well, Einstein had had conversations with two guys, Podolsky and Rosen, about what he felt was an issue that quantum mechanics was correct, but it wasn't finished yet. It wasn't complete. And guess what? He was right. It still isn't complete. So that book is by Cambridge University Press, which has quite the catalog of astronomy and physics books for the public. Yeah, and I mean, the book is intended for people who are interested in learning from the physicists at that time themselves, their philosophical and physics sort of worldviews and learning about this history.

3:29I don't understand the use of philosophical when it comes to their physics. Let's start right there. Yeah, good. You are a professor of philosophy specializing in the philosophy of physics. Yeah. So what is the philosophy of physics in modern times? Because I know what it was in the day. Because in the day. What's the day? Antiquity or the Renaissance? No, post Galileo. Okay, Newtonian worldview. Yeah. Okay, got it. Yeah, back then. Scientific revolution. Yes. You got it. Back then, philosophers were physicists. I mean, they were one and the same. That's right. And in fact, Newton's greatest work has the word physics.

4:11The word physics isn't even in the title. That's right. The Principia doesn't even have equations in the first part. Okay. The title is, well, in Latin, but it's The Mathematical Principles of Natural Philosophy. Okay. That's right. Natural philosophy fits the same thing. Natural philosophy. Yeah, natural philosophy was physics. It's the deep thinking about how nature works. Okay, so we got that. But into the 20th century, you get quantum physics, where you can't deduce from an armchair, and you have an expanding universe who thought that up. And the confirmation of all these things that were mathematically postulated and then proven to be the actual case.

4:48So what I noticed was that there was a sort of a separation of the turf. Yeah. And the philosopher couldn't really contribute to physics unless they were actually a physicist. You could still think philosophically, but you needed to be in the lab. You couldn't just sit back and observe and think deep thoughts. Well, Einstein was never in a lab. Right, but he was a physicist, not a philosopher. I don't think he would make that distinction. Let me say it differently. Okay. He was trained as a physicist, not trained as a philosopher. Oh. And that's the distinction I'm making. So here's the real test.

5:27That is the distinction I'm making. If Mel Brooks were doing a sketch with him, would he say to Einstein in the philosopher unemployment line, did you bullshit today? Did you try to bullshit today? Are you planning on bullshitting in the future? Is that from History of the World? History of the World. That's History of the World. That's the actual quote. Yeah, so I'm distinguishing between people who go to school to be a philosopher and then attempt to contribute to the physical sciences. Whereas that, you could do that in the day. And I don't see that happening today unless you're busting that wide open in your existence in the world and in this office right now.

6:07Yeah, yeah, yeah. Okay, a couple of comments. First of all, in the German university system in which Einstein and Schrodinger and Bohr and all these guys were trained, they learned a hell of a lot of philosophy. Sure. And even Einstein into his post - I'm not saying people didn't have philosophy chops. I'm saying if you go to school to be a philosopher, in the 20th century, Fair enough. you became less and less useful to the moving frontier of the physical science. That's the only point I'm making. Now go. Unless you go bust that open. Well, the first thing is I don't accept your premise that in order to do what I do.

6:39That's how you start an argument. That's how you start an argument. How do you start and win an argument? We're welling our way into a philosophical debate. Your premise is invalid. Okay, go. Well, a premise can't be invalid. Only a whole argument can be valid. But I'm being an asshole on purpose because it's funny. The idea that what I need to do is be useful to science to be important or worth doing as a human endeavor is a pretty narrow view. Except that's how it used to be. And that's - How what used to be? Philosophers were useful to the moving frontier. You have Kant thinking up stuff. The nebular hypothesis was kind of cool.

7:19And you had - So Einstein's own ability to get the theory of special relativity had to do with his taking a different approach than Lorenz and Poincaré and others who were looking for a similar theory. Yes, exactly. Let's step back. That is a choice to step back and say, we have these data, let's understand them a different way. I'm not saying - Now, if you're saying it's about how we specialize in the different disciplines, yes. Yes. That is something that naturally occurred as our measuring apparatuses and our technology got better, we were able to be like, and you go to a conference in astrophysics nowadays, how many talks do you even are interested in?

7:57Like hyper-specialized. Fair enough. Yeah, I published a paper, a hundred people in the world will understand it. Or no, a hundred people in the world will care about it. Right. For me, it's like maybe six. Oh, this works. They're my buddies, you know? Okay, yeah. It's like when people are like, oh, how do I find you on the internet? Like Google Elise and philosophy of physics because I think I'm the only one. Let me back up as a layperson and kind of broaden the view here. The intertwining that Neil was talking about that existed at one point that you now say has kind of dissolved because of highly specialized training.

8:36Yeah. Where does that intersection happen now? Good. Yeah. Good question. That's great. And I think that's exactly the question we want to. So you're asking, am I going to blow it open now? Yeah. I think the fringe, like the edge of science right now is in this place. So you're talking about people who are looking for a theory of in this place. In this place. In this place, metaphorically and morally. At the hate point of time. Right now. It happens here and now. Localized entirely in this room. We're in the room where it happens. Okay. Okay. We're getting beyond our means to empirically test.

9:15And you know, as a cosmologist and astrophysicist, there's a limited amount of data that we - On that frontier, yes. On that frontier. And that's true also in looking for theories of quantum gravity. Yeah, all of that. I mean, we haven't yet found conclusive evidence for the Lambda CDM model that is only for the Lambda CDM model of cosmology. It's the best we have right now. It's the cold, dark matter and dark energy. It's just - The concordance model, like the model we think is the best model of the universe right now. I didn't just catch people up. So we know the universe is accelerating in its expansion.

9:47And what's causing that, we call dark energy. We just call it that. We don't know. But it's a black box, quite literally. And then dark matter is a mysterious source of gravity in the universe. In fact, it's 85 % of the universe's gravity. And we don't know what that is either. But if we assume it's a thing because we measure it and then we can calculate with it, and with some assumptions about the behavior of matter, we get a sort of a kind of our own standard model of how the universe works. It's called lambda-CDM, lambda-cald dark matter. And we work with it, it gets us some understanding. Yeah, it does some good work for you.

10:26Yeah, it's our workhorse. But we don't have direct. But it's not a complete picture. It's a complete theory, okay. Right, so this is true in a lot of arenas of physics, and so what philosophers of physics can do, although I think there are many ways to be a philosopher of science, It's not just like you're trained in philosophy, but you sort of ask philosophical questions of science itself. How many philosophers of physics are there? I don't know. More than five, but less than 200? Okay. Well. No, maybe there's more than 200. It's hard to say. You're the first one I've ever met. Oh, really? Yeah, I've met philosophers, but just think about everything.

11:05Right. It's a small field, to be fair. And I will also say, back to your early point, most of us have training in physics as well because that's important to us. You're an undergraduate. My undergrad is in physics, but then I also continued. I mean, I wrote my doctoral thesis on quantum decoherence, so I was learning about the models that people are using. You have physics jobs. So was that in the physics department or in the philosophy department? So I was in the philosophy department, but I was part of a history and philosophy of science program, but I also took a number of physics courses. From the physics department.

11:35Okay, so you're just blending all of that. All the things. You just put it all together. That's what we need for someone to bust out. That's a great way. To bust a move. That's a great way to make sure that you get an A. Why? Because. Yeah, how does that correspond to getting a good grade at all? Here's how it works for getting a good grade. Oh, good. I'm listening. So you have your philosophy people, they don't know crap about physics. And your physics people, they don't know crap about philosophy. So you're just like, yeah, you're going to have to take my word for it. That's exactly right. We're all just pretending.

12:09No, go ahead. So this ties into your early question. It's like something about the extreme specialization has meant that in particular, the way we train physicists in the US, even in high school, is so divorced from the deep questions about but why and but how. It's about following a scientific method. Did you study abroad? No, but I've studied, I've looked at education policies in other countries and sort of, it's no surprise that we're not, you know, we're still the best place to go for STEM at the graduate level. Right. But that's, we're losing that. Yeah. And there's a history about that. In particular, there were decisions made in the Cold War era to train people in science in a particular way that was gonna get technologies built, that was gonna be good for industry and for the Department of Defense.

13:04That's right. Weaponry. And it became not just not in vogue, but like it became - In fact, I have the original document in this office. Of the NSF creation of - Yes, I have that document. Can I reach for it? Yeah, show it to us. Let's have a visual here. This is what you were talking about. Yeah, Vannevar Bush. Let's let our people at home. Making a case for why America needs to preserve and fund science. And I think that was an easy case to make because it was physics that won the war. Well, that definitely helps an argument. I'm just saying. But there's a...

13:46This is good. This is good. This is funny. That's funny. Science, the endless frontier. Ah, yes. A report to the president. Yeah. This is 1945. Oh, wow. This established - So this went to the president, this right here. No, this, he, Vannevar Bush, was basically the first science advisor to a president. Okay, right. Okay, and he's advising - I don't need one of those. Nobody knows more about science than I do. That's really good. I know. He's got - I'm getting angry over here, just kidding. That's how you know it. So here's what I want you to do. Just read the chapter, the section headings there.

14:22Just read them. Read them. Introduction. Well played. Okay. Excellent. The war against disease. These headings, you mean, are like science and public welfare, renewal of our scientific talent, a problem of scientific reconversion, the means to an end, responsibilities for the government. Yeah, the means to an end. Okay. Okay, so everything I know and think of about how science happens in the United States, when I pull up this original document, it's all there. And so I have, maybe, is it a bias? I say, that's how you do science. But are you suggesting there's another way to do science? I'm suggesting that when you get to the level of how we educate, when you divorce, you understand science as a thing that's about usefulness and application.

15:13that is one very small color from a spectrum of colors. And I'm also suggesting that when we look at people who are trained in the history and philosophy of science, along with the science itself in high school, they're testing off the charts. There's something about being able to answer that or ask that, why? Why are we using this equation to solve for the energy level of a hydrogen atom? Why are we understanding? That never showed up in any of my classes. That's right. That's absent. Were you taught? You were taught. It's amazing to me that - I was taught physics as a thing, not as a way of thinking.

15:47That's right. I had to realize that it was a way of thinking and bring to it the bit of philosophical meanderings that I had engaged in my life. I had to bring that to the physics. That was not there when it was taught. And you're told not to have it there, right? Well, not explicitly. It's not encouraged and it's not rewarded.

16:15Hi, I'm Ernie Carducci from Columbus, Ohio. I'm here with my son Ernie because we listen to StarTalk every night and support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

16:36Okay, let me ask this. So what is it about asking these big questions? The why questions. The big why questions. What is it about that that contributes to the guiding principles of science itself? Because there's no one recipe for how to do good science. Okay. Okay. It is true. When I go to my different science, everybody's got their own angle on science. It's true. There was no centralized approach. Right. Well, but even if there were. So you're telling me that this centralized our approach, not to our greater good. I think it did in some ways to our greater good because, I mean, Vannevar Bush wanted the inner core of funding for NSF to be pure science.

17:26He thought there was always supposed to be a part of it that wasn't. Whatever funding is left of it. Let us hang our heads in a moment of silence. Do I get a plane from the NSF? But did you know that if you drop a magnet into a glass of water, it loses its magnetism? Yeah, he said that. He said that. I love it. He said that. Yeah. And by the way, I'm still right. But it has to be Avion water. It's just a...

18:00Sorry.

18:04I'm sorry. Go ahead. Why do you keep disrupting the lady? I know. I'm so sorry. No, it's good. This is like real world out there, right? It's like we're trying to do scholarship and then things. Right. But also, let me ask you this, Neil. Would you have been interested in doing science if it was just told, if it was taught to you as like following a recipe? I had to. Like the scientific method. My philosophical interest in the universe was self-driven. It did not come from any book that I was taught. Right. And my writings today, I don't want to say they're dripping with philosophy, but they take an angle on the content where it's not just here, learn this.

18:43It's think about it in this other way. That's very cool. So, I mean, here's a metaphor, if you like. I mean, a lot of people can follow recipes and make really good dishes. really tasty dishes. So there's something wonderful about that. But the truly inventive chefs are the ones who say, well, or even the better cooks, I'm a terrible cook, but like are the ones who say, but why do I melt the butter to this temperature? Why do I add the salt at this stage? Or why is this, these flavors work together? Expertise is something that our country is not, has a very interesting relationship. It's been devalued lately.

19:17Yeah, that's right. So let me ask you this. Often philosophy is thought of as a belief system. But in science - Let's so in the sciences. Right, that's what I'm saying. But in science, you definitely don't want to be biased by your beliefs. So the one thing you want to do is divorce yourself so that whatever results you get, that you're able to accept irrespective of how you feel about them or what you believe, how is that reconciled? Good. And let me add something to that. Yeah, ooh, it's a lot of good questions. Let's go back to Kepler, who was, dare I say, philosophically driven to think that the orbits of the planets could be nested in such a way that they resembled the platonic solids.

20:11Nested spheres, which always makes me think of Tupperware for some reason. So what he knew was that geometrically in mathematics, there are only five what are called platonic solids. These are solid shapes where every surface is the same two-dimensional shape. So a cube is such a thing. Every side is identical and has six sides. A pyramid is the same, okay? Okay, four sides, so you have four triangles, and they can all be equilateral triangles. So there are five of these shapes. He saw that there were six planets, and he thought to himself, maybe there's a divine connection between the two. Because the planets, it's the universe.

20:59It's where God lives, right? And then we're just mere mortals here. God surely knows what he's doing, and math is perfect, right? Math is badass. So he nested these in different ways to try to find out whether the separations of the planetary orbits could match what these solids would be if they were nested Tupperware style. He was also thinking in terms of harmonic resonances, but yeah. Right, and so my question to you is, I don't wanna say he wasted 10 years. He devoted 10 years to this point of view and it took him that long to abandon it in favor of something that was not so philosophically beautiful.

21:41So in that case, getting back to Chuck's point, the philosophy prevented him from seeing the answer because he was driven by this concept of divine perfection. So there's a couple of different ways we're talking about philosophy, right? There's the philosophy of just, I mean, if you go to a philosophy section at Barnes & Noble's or whatever, what they have there in the metaphysics section is some weird new agey stuff. It has nothing to do with what academic philosophers are doing. And academic philosophers are asking questions about what is the nature of personhood? What is knowledge? Do different people reason in different ways?

22:20What are ethical questions? Like what is the philosophy of law, philosophy of science, these sorts of things? We have specific tools that we bring to bear on that. When scientists think about it, I think they're understanding not philosophy as a discipline, but they're thinking about like a worldview. And we come to everything with a worldview, with a lens. That's inescapable. Now you're right that part of what scientists want to do is sort of shield, maybe not shield for that or at least neutralize it in some way. We want to think about whether our comments are value laden. And I don't just mean value in an ethics way, but maybe also do I privilege certain epistemic values like beauty or similarity.

23:02And many do. Many do. But I can tell you this, to the extent that I can understand myself, I leave all philosophical preconceptions at the door. You can't do that, though. I said to the extent that I am able. I'm self-aware that I could be constrained by a philosophical thought. So I remain open to anything I see and anything I measure and what that could possibly mean and without discounting it. And the reason why I'm going there is I had an issue in Hamlet. Okay. One of the lines is there's more betwixt heaven and earth than I dreamt of in your philosophy. Right. And I never understood that comment ever because as a scientist, if a ghost shows up, I'm fine.

23:52Let me make some measurements. I have no issue with that. So why does that sentence make any sense at all until I realized that people who are deeply into a philosophy of belief do close off their access to things that fall outside of their understanding or their awareness. So a good scientist has no philosophy, otherwise they're gonna miss stuff. Bad scientists will have a philosophy and they'll miss everything. Your choice to set aside some world, so that you can be neutral is itself a philosophical position. Oh, okay. That's a very good point. That is ineliminable. In a what? Ineliminable. That you are going to walk in with some interpretive framework.

24:37Ineliminable. Ineliminable. Cannot be eliminated. Cannot be eliminated. Ineliminable. I've got some big words here. I would say that the philosophy that I have no philosophy is a very mild version of a philosophy. The point is that you cannot. Yeah, I was going to say, she's about to tell you. I'm listening. No, she's about to say, that's like being a little bit pregnant. Okay. You can't be a little bit pregnant. Can we hear the lady? Okay, go. Yeah, well, so when you walk into the lab or whatever, it's not like you take off your religious hat or you take off your culture. You're an integrated whole person.

25:18And how you were trained and what you were thinking about that morning and what you're predisposed to look for in the equations themselves, those things play a role. Now, there's a huge conversation in the philosophy of science about whether certain things are more or less appropriate when you bring in. But that you bring something with you, that is how we do. Science is a personal and social endeavor. So all I did say, I think, was I reduce it as much as I knowingly can. That's what you said. So what she's saying is there's no extent to which you can actually know because the holistic person that you are, you are inexorably tied to your philosophy.