The Joy of Why - S4 Preview: More Big Questions and No Sasquatches

Episode Date: March 13, 2025

How did complex life evolve? Where did space-time come from? Will computers ever understand language like we do? How did geometry create modern physics? These are just a few of the big and bold questions that we’ll be exploring in the latest season of Quanta’s interview podcast, “The Joy of Why,” starting March 20, and released every other Thursday.As ever, we will be talking to researchers and exploring the latest thinking on great scientific and mathematical questions of our time. But this season sees a new format, with the two of us — mathematician Steven Strogatz and physicist Janna Levin — together in conversation for the first time to offer our own thoughts and questions about each topic.As a preview, we discuss why we are particularly excited about the new season, and we reveal our favorite standout moments from the previous season.

This is the joy of why. I'm Steve Strohgatz. And I'm Jan Eleven. And here we are together. This is a little different wrinkle for us. Last season we took turns at the microphone interviewing guests from all different walks of science and math. Now we're some kind of team.

We're going to sit down together more. We're going to interview big scientists about big ideas. I'm really looking forward to it because, first of all, it's fun to work with you. You can always learn a lot from your friends. But what do you think is being brought to the table by having us do this together? Well, I think that we have an opportunity as research scientists to dig really deep into particular ideas of our choosing, but we don't really get a chance ourselves even to talk to other people deeply in other fields. And I think that's going to be a real pleasure.

We're going to home in on four pillars that Quanta covers, like math, physics, computer science, and biology. I think it's great to single those four areas out because they are very important to us at Quanta and at the Joy of Why. There are all kinds of great science outlets where you can learn about applied areas like climate or health, engineering. Yeah, I sometimes worry that a lot of people are consuming science that really is kind of all about ourselves.

How is it going to make my life better, you know, extend my life? So it's a lot of medical and health, but I really sometimes feel blue skies and the big dreamy ideas, that's actually really valuable for us and a good way to keep the world in perspective. Yeah, we also won't be covering Sasquatch or ESP or alien abductions. You just lost us half our audience. I know. I wish I had their numbers. Their ratings are incredible, those Sasquatch people. But this is actual science we're going to be doing here. I really think our audience will find their curiosity sparked.

We often ask our guests a question which actually I'm going to ask you, Steve, which is, what brings you joy in your science? Well, math generally, but especially how math connects to the real world. I'm what would be called an applied mathematician, and so that means, where's the hidden math in the phenomena around us? Like why are we all just connected by six handshakes? How can we learn about our DNA by thinking about it as if it were a twisted rubber band?

So these kinds of ideas where math connects to everything, especially things that don't seem overtly mathematical, that for me is what makes me want to wake up every day. How about you, Jana? What would you say is the thing that brings you joy as a scientist, also as a science communicator? Yeah, it's not entirely dissimilar. A lot of the work I do is really connected by thinking about space and time.

So that could be about the Big Bang or black holes or quantum field theory and extra dimensions, but these are all very mathematical subjects. And I marvel that we can follow the math into making physical discoveries. It still astounds me. Looking back over last season, what were some of your favorite standout moments? Well, there were a couple, and for different reasons. A lot of us as scientists just like to do what we're curious about. So one that I just can't get past, I love thinking about this, is something that Shai Shaham, a cell biologist who was talking to us about cell death, I asked him

something in regard to a comment that Francis Crick of Watson and Crick, DNA fame, had once said that it's just as easy to work on an important problem as a trivial problem. And does Shy ever think about that when he's doing his work? Does he try to select problems based on their external importance in some sense? I've often thought of that quote in trying to decide what my next goal should be. But I will tell you that in my opinion, I lack the hubris to decide what's important and what's not.

And I think science has proven over and over how discoveries that seemed unimportant and fringe at any moment turn out to be all the rage just a couple of decades later. And I just think my imagination, good as it is, is just not good enough to be able to foretell the future like that. And then there was one other moment that caught me off guard for a different reason when I was talking to Nigel Goldenfeld, a condensed matter physicist, about magnetic phase transitions and more broadly the question of why we can even do science at all. And it was both hilarious and illuminating.

Here's Nigel on that theme. So, suppose you said to a scientist, okay, make a theory for me of a magnet. So they'd say, well, a magnet is made out of atoms. So in order to understand atoms and how they interact and become magnetic, I need to worry about the electrons on the atoms. I need to worry about the magnetic moments of those atoms. And so I make a model of the material based on quantum chemistry.

But that model is unimaginably complicated. So then you say, let's simplify it. Let's just worry about how the electrons move around in the material. So you go ahead and do that, and you find you've got a complicated model of electronic structure, and that model is too hard. So then you say, let's take the thermodynamics,

and that's a model where you can finally do a calculation. You've got one, two, three, four, five models of a model of a model of a model of this material. And at each step along the way you have made an approximation that would be rejected from every physics journal because everybody would say that that's approximation you can't justify, there's no small quantity, no idea what you're talking about, how can that possibly work? You know for me I was really struck when I was talking to Penny Boston who's a microbiologist who studies extremophiles. She was describing these simple organisms that metabolize minerals or just oxygen or

just hydrogen. It really made me question what we mean by life. Why are caves of particular interest in your area of expertise? What is unique about subterranean microbiology? Yeah, I mean, so I could just regale you for hours, but I will spare you. I'll just get on the high points. There are some really clear advantages. One is that you can consider a cave a semi-closed system. And when you look at the genetics of the organisms that we find there, we find vast biodiversity. And we also find that most of the organisms

are not the ones that we find on the surface, even on the surface right over a given cave. So what that says to us is that however organisms get into a cave, they're immediately subject to really different conditions. And that promotes an evolutionary pace that pushes them in the direction of becoming a very unique little biosphere, miniature ecosystem, and that each cave has the potential for doing that.

And so I think of them as little baby planets that we can study. Talking to Lenny Suskind also was so much fun. He was talking about his conflict with Stephen Hawking, who was also his friend, and how they had a battle over black holes. And in his book, The Black Hole Wars, the subtitle was, My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics. So the information that fell in, even if the black hole evaporates, it's like you're yanking a curtain up, but the stuff is gone. And there's nothing you can do about it.

And he fell down on the side of information was lost, but you said, wait, there's no way. Why was it so important to you to say information cannot be lost? What's so bad about that? Hawking was saying what comes out of the black hole will be absolutely independent of what fell in. If you follow that light of reasoning and ask what it implies, it implies chaos. Nothing makes sense anymore. I just hope that couldn't be right.

How contentious, how heated did this become, this debate? In a personal sense, not at all. Stephen and I were good friends. There were times when my wife and I and whoever he was with at the time would have dinner together. He would challenge me. He was 1000% certain of what he was saying. Of course, I was also 1000% certain of what I was saying. If you don't mind me quoting you, I believe it was in the Black Hole War, you said Stephen

was also a very arrogant man. And then you said, so was I. All physicists who are ambitious and really want to get somewhere in the subject have to have a certain degree of arrogance for sure. You have to believe not only that the human brain is smart enough to unravel these incredibly sophisticated ideas, you have to believe that your human brain is smart enough to do that, to be able to figure out quantum mechanics, smart enough to be able to figure out how the universe works.

On the other hand, you also have to be very clear about what you don't know and what you're very, very far from and what you may never know. Another standout moment for a completely different reason was just the shock value of something that Terry Tau said to me. Terry is one of the world's greatest mathematicians, and I was curious about where does he go when he wants to learn some new math? Here's what he said. The fact that I can go on Wikipedia or whatever

and get started learning a subject, and I can email somebody and we can collaborate online. I've had to do things old school where I could only talk to people in my department and use physical mail for everything else. I could not do the math that I do now. Wow. All right.

I just have to underline what you just said because I never thought in a million years I was going to hear this. Terry Tau reads Wikipedia to learn math? As a starting point. I mean, it's not always Wikipedia, but just to get the keywords and then I will do a more specialized search of say MathsCylet or some other database. But yeah. It's not a criticism.

I mean, I do the same thing. That's just funny. I love hearing that. I mean, these tools, you have to be able to vet the output. So I mean, the reason why I can use Wikipedia to do mathematics is because I already know enough mathematics that I can smell if a piece of Wikipedia during mathematics is suspicious or not. You know, it makes some sources and one of them is going to be a better source than the

other. And I know the authors. I have an idea of which reference is going to be better for me. If I use Wikipedia to learn about a subject that I had no experience in, then I think it would be more of a random verbal. So, Jana, if you'll forgive me for saying it, I think of you, in addition to being a great scientist, as a very lyrical and even poetic writer. And... It's very kind.

But you deserve it. And I would like putting you on your poetry hat for a second. Was there any kind of moment in last season where a scientist sort of reached levels of poetry in their explanations to you? Oh, yeah. There was a really nice moment with Claudia de Rham when she described gravity, which Einstein also famously did, as a state of falling. So she talked about how to understand space, time, and geometry as a state of falling and weightlessness, which seems really counter to what we usually think of as gravity, which

is kind of a heaviness. And I thought that was very poetic and very beautiful and a reminder that these very elegant ideas really do help lead us to discovery. Here's Claudia actually talking about that. We experience gravity as, for instance, your chair or the sole of your shoes or anything that holds you on the surface of the earth. This is the pressure in which we feel gravity. But the reality is gravity feels nothing. It's just freedom in some sense.

When something falls down and crashes on the floor, if you have a broken leg or a broken vase, you may think of this being gravity, but that's actually not gravity itself. That's just the end, the end of the fall, the end of gravity. The beauty of falling is actually it's completely free. You are experiencing gravity in one of its purest possible way with nothing stopping you from this experience of complete gravity. Yeah, the astronauts in the International Space Station are floating, not because they don't feel gravity, but because they're falling. They're falling around the earth. That's right, because they're feeling nothing but gravity, and that's what

allows them to experience it. So we got to talk to a lot of pretty amazing people last season. What are you hoping for this season? What are you excited about? I am particularly curious these days about machine learning and anything to do with artificial intelligence. You just can't really get away from it. And I would love to have some of our guests

explain to me what's coming down the road. What are the big puzzles? What are the big opportunities? What's scary? What about you? Anything that you're looking forward to? Yeah, I think I often seek out kind of the blue skies ideas when life is a little stressful.

I find it very soothing that instead of getting into the immediacy and the minutia and the woes in the world to think about the big ideas. So I'm also interested in hearing how people came to those ideas themselves. Right, it's not just big ideas. So I'm also interested in hearing how people came to those ideas themselves. Right. It's not just the ideas. We also want to illuminate not just the science, but the scientist, right? Their inner struggles. Yeah. It's a human endeavor. It may be true that we want reproducibility for science.

And if Einstein didn't do it, somebody else would have, but it still was Einstein. These are still the people making these discoveries. And it's a human endeavor. We can't forget that part. That one is fun for me to ponder because I often think of Einstein as the one example of someone who, if he hadn't done it, nobody would have done it. You know, it might have taken a lot longer. Maybe it would have taken another hundred years.

I don't know. But that's the really magical aspect of science. We might have gotten there by quantum field theory instead of the way Einstein got us there. We might not be talking about geometry as much if Einstein hadn't given us that machinery in that language. But we would have gotten there to the relativity of space and time. Maybe, I don't know if we're getting too much into the arts here for a science show, but we did talk a little bit about poetry. And I think there is something poetic about

the fact that Joy of Why is produced by Quanta Magazine. And that's an interesting choice for a name of a science magazine that I feel like has maybe potentially poetic resonance. So as our resident poet, what do you hear poetically in the name quanta, if anything? Yeah. Well, quanta is an individual corpuscle of something. And so maybe it's conceptually we're tackling these individual grand leaps of ideas in their different fields and the different technical subjects.

Uh-huh. So along with this particularity aspect, let me suggest it might also have something to do with photons. That when Einstein in his photoelectric effect gave us the ideas of quanta of light, You could even say quanta makes a good name for a science magazine because we're illuminating one particle at a time, the whole landscape of science. So that actually brings us back to how we met. I don't know if you would remember this. Do you actually remember the first time? I think so.

In my memory, it was that I had read your first book, How the Universe Got its Spots, soon after you were a postdoc. I think you were just a beginning as a professor. And we were having an event about science communication. And I was so entranced with your book, and also just your lyrical writing, and I couldn't wait to meet you. That was my memory too, and that is so sweet. I remember right away we're talking about writing and math and writing and math. And I do think that there's a poetry, both in the mathematics and in the written word.

Different kinds, but it's there. It's our first chance collaborating. We have never written a paper together. And so for me personally, it's a really big thrill to be your partner on this show. And I don't know what we're gonna end up talking about or learning together, but I can't wait to find out this season. Here on The Joy of Why from Quantum Magazine. Oh, I can't wait. See you soon. See you soon, Steve. you