StarTalk Radio - Our Mathematical Universe with Grant Sanderson (3Blue1Brown)

Episode Date: September 24, 2024

Is math discovered or invented? Neil deGrasse Tyson & Chuck Nice explore information theory, talking to aliens with prime numbers, Mandelbrot sets, and why math is often called the "language of the universe" with Grant Sanderson, the math educator behind YouTube channel 3Blue1Brown. NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free here:https://startalkmedia.com/show/our-mathematical-universe-with-grant-sanderson-3blue1brown/Thanks to our Patrons Dr. Satish, Susan Kleiner, Harrison Phillips, Mark A, Rebeca Fuchs, Aaron Ciarla, Joe Reyna, David Grech, Fida Vuori, Paul A Hansen, Imran Yusufzai, CharlieVictor, Bob Cowles, Ryan Lyum, MunMun, Samuel Barnett, John DesMarteau, and Mary Anne Sanford for supporting us this week. Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

Chuck, we finally got a math person as a guest on StarTalk. And one that I actually like. Sometimes it's very difficult to like math people because, you know, they know math. an authentic math educator who's going to tell us what we're not thinking when we should be thinking anytime we think about math on StarTalk. Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk. Neil deGrasse Tyson, you're a personal astrophysicist.

Chuck, nice with me. Chuck, how you doing, man? Oh, man, I'm feeling great, Neil. Professional comedian and my co-host. That's correct. In that order. Sometimes. Sometimes in that order. So, Chuck, I think this, we this we're gonna parts of this is going to be a cosmic queries yes but we have a lot to cover so it's not going to be a full-up cosmic query it's going to be let's slip in what we can because the subject is math what the language of

the universe learn math kid it's the language of the universe you want to talk to the universe you learn math learn math and there's one of the funnest experts out there okay on this very subject and his name is grant sanderson grant welcome to star talk lovely to be here thanks for having me yeah you, you studied math in college, and you came out and you worked for the Khan Academy. Oh, the Khan Academy. I know. If you've never logged into Khan Academy, you go there and you can learn everything about everything. And they care about how you learn. They don't just slap you with a textbook. And it's a everything about everything. And they care about how you learn.

They don't just slap you with a textbook. And it's a completely different experience. I would call it even joyous, learning about practically every subject there is to learn. And if you fail to learn, you can look over your head while clenching your fists and going, Con! It's a real opportunity. Star Trek reference there for those who are not geek enough to catch it. Right. So Grant, you have multiple math platforms.

You have a podcast, blog, YouTube, you have brilliant postings that millions of views. And this is not trivial math that you're doing. It's like real. When I say real, I mean, it's the kind of math that most people would walk by and say, I don't need to know that. I don't want to know it. It's got nothing to do with me. Yet you somehow turned the tables on that. Now, before I ask you my first question, Chuck wants to ask you his first question. Yeah. I ask you my first question, Chuck wants to ask you his first question. Yeah. And here's my first question, Grant. And it may sound a bit glib, but it's not. I'm very serious. What the hell is math? Okay. What the hell is math? What the hell is math? What the hell is math? Okay. Here's why I asked just so that you'll get a bit more context okay one we started off by saying hey it's the language of the universe you hear that

all the time but when i think of it i'm like all right so we have these symbols and we've attached values to these symbols and then these values have concepts that are surrounding the values and the symbols. If I came from another galaxy, I wouldn't know your freaking math. So how is it the universe of universal language? Well, okay. So it reminds me a little, this question came to me in another form. I was at this wedding recently and a person I was just meeting there who knew I did online math stuff said very sincerely, like, why is geometry math? Which is a different question from what you're asking, but it's sort of kids in this, what do we even mean by math? And I initially answered saying, it's something that we can know very precisely. So one of the oldest texts in math is Euclid's

Elements. And one of the things he did there is he starts by laying out some axioms saying, assume these things are true. Assume that lines are a thing. Assume that points are a thing. Assume that if you have a point that's not on the line, it's possible to draw a line that's parallel to it. These sorts of things. And with just five of these assumptions, then proves, rigorously proves things that have to be true beyond any doubt.

So in every other field, there's a little bit of doubt. In every other field, you've got this little thing in the back of your mind that asks about experimental error, asks you, maybe I didn't observe what there should be. And the thing that really separates math out from the other things is that assuming you agree on the axioms, everything else, there is no more doubt. It's a truly rigorous proof. So we can say that aliens might use different symbols, but ultimately we're thinking math is out there to be grabbed by whoever has the capacity for logical thought. But it raises the question, what are the axioms? Where do you start? in an undergrad math major, you take all of these courses like group theory or topology or whatnot,

and they always start by saying, here's some definitions. I'm like, here's the definition of a group and yada, yada. It's a set with some added stuff. It looks like gobbledygook. And then you proceed forward and prove stuff. But I think a very reasonable question that the students could always have is like, why is this the object we're starting with? We could construct all sorts of other objects and move forward. And so there is this interplay with how it relates to the world and whether the math that you're developing is useful or not. Because I think if you take like a purely logical standpoint, you can develop a whole bunch of useless math. And in fact, you could ask if some of the math being developed now, maybe'll never be useful. But history has this strange trajectory of things that seem to be useless coming back

and being useful. But it's a real deep question. Why? There's some mathematicians who do math only because they're pretty sure it will never be useful. Well, I mean, there was this rather famous mathematician, Hardy, who, this was around the time of World War II. He was writing this book called A Mathematician's Lament, or sorry, A Mathematician's Apology. Hardy was one of the teachers of Ramanujan, if I remember correctly.

He was, yeah. He was the one who answered Ramanujan's letter and brought him in. Great mathematician. And he was played by, who's the actor in the film? Jeremy Irons, I think. Jeremy Irons, I think. Jeremy Irons. In fact, those who love our archives can dig up our Jeremy Irons interview where we talk about that film where he played Hardy the mathematician. And to get his reflections on what that whole story meant to him.

So I'm sorry. I'll have to check that out So I'm sorry. One of my favorite actors combined with one of my favorite people in history. So it's like, Oh, it's just such fate for me. I can't believe I haven't listened to that. But I mean, Hardy wrote some, he was sort of delighting in the fact that math will never be certain kinds of math. And he was highlighting, you know, the theory of prime numbers and relativity will never be used as instruments of

war. Um, which is, is this irony looking back because prime numbers have a lot to do with cryptography. Relativity has everything to do with GPS and everything with that. That idiot. But the fact that he delighted in it is a little strange, right? And it's something you would only expect from an academic maybe, but it's like, even when they're trying not to make it useful, right? Even one of them is trying not to, it seems to kind of come back. And so to your question, Chuck, on what is math, if we just said it's the things that we can know for sure, that doesn't really feel satisfying because that somehow doesn't tie into this bizarre fact where it also describes the world i would add that in the film contact not in the book but in the film

the aliens first communicated with us using pulses yeah that traced out prime numbers right it's you know it's a special there are a lot of special sequences that's probably the simplest of the special sequences. So that was another use of prime numbers. If we didn't know anything about prime numbers, that's going to say, let's say for instance, we call them prime numbers,

but are those values universal? So I think you meet an alien species, they come to earth. You say like, do you know about prime numbers? They don't know the language. They're going to be like, what do you mean by this word? Prime start tapping out like two taps three taps five taps

you do that the alien species has done like any thinking at all they'll be like i got you i got you i got you it's such a natural sequence it's it's like as soon as you have counting numbers and then you start to ask curious questions any intelligent entity is going to stumble on like primes being a thing. Just to be clear, all of this assumed that they count in base 10. No, it doesn't. It doesn't at all.

Yes, it does. No, no, no, not if you just tap twice. So how do you write down the number? Yeah.

That's what you call it. Write down the number. You got it. So we would write one, three, maybe they have a different base 10, but if you just do 13 taps and then you do 17 taps, right. And you keep doing all the number. You got it. So we would write one, three. Maybe they have a different base 10. But if you just do 13 taps and then you do 17 taps, right? And you keep doing all the prime.

Like any, you know, any AI, any alien, all of them are going to be in agreement that like this one's important. They're tapping out the glypsorpian sequence. Wow. Exactly. Exactly. Yeah. Chuck, know your prime number is just for this. Just in case I run into an alien.

Right. Chuck, know your prime number for this just such an emergency. Just in case I run into an alien. Right. So I hate to ask you this question only because I don't like the question, but why not ask you? I'll tell you why I don't like it in a minute,

but is math invented or discovered? Well, it's okay. And forgive me for asking that question. No, no, it's a super common question. Let's do an example rather than like philosophizing. Okay. So one of the first substantive theorems that students learn in school is the Pythagorean theorem. So at some point, whether or not we've forgotten since then, many of us will have come across that if you have a right triangle and you label the two shorter sides A and B, and then the longer side C, no matter what right triangle you have, A squared plus B squared equals C squared squared.

It's a cool fact. It's not obvious that it should be true. It's useful. It lets you make sorts of measurements. And it's the first one you meet that it doesn't just fall out of definitions. It's interesting and it's all that. Now, if you ask, is that fact invented or discovered? Initially, it feels like, well, it's discovered for for sure you go out in the world you see right triangles you kind of you you can measure them it's waiting there for you to see it and notice it's waiting for you to see it but then you get a little further in math and then you start to ask questions like what is space what is you know three-dimensional space two-dimensional space and things like this and then one of the ways that mathematically you're defining two-dimensional space, two-dimensional space, and things like this? And then one of the ways that mathematically you're defining two-dimensional space is rather than saying,

oh, it's this pre-existing thing and we can put a coordinate system on it, a lot of math will start from the coordinates themselves and saying it's all pairs of real numbers. So rather than saying, oh, there's this plane out in existence, and then you put some axes and you say, this is your x-coordinate, this is your y-coordinate to get to a point on space. You say, rather than all the tricky philosophical questions about what is a plane and whatnot, we just say, a plane is all pairs of real numbers. That's what it is. And then you can do math forward. You can make proofs and whatnot. But then when you say, what's the distance between two points? And you have to assign what they call a metric to the space, a way of telling distances. You sort of make the Pythagorean theorem true by writ. You define a metric that makes it true,

and there's choices for other metrics that you could have put on it. And then it starts to become kind of sticky, like, wait a minute, was this discovered anymore? Or if this is how we're doing all of our math, where we say a plane plane is just pairs of numbers and that's mathematically what it is then then you don't have that same like oh it was waiting there to be discovered wait so grant how different is what you described from knowing that there's a variety of space where pythagorean theorem applies as we learned it but if you curve the space then triangles are different right the a triangle the angles sum to more than 180 degrees where a traditional triangle especially a right triangle it all comes to exactly 180 so this would be a different metric for the space yeah i mean so the idea that you can put different metrics on is sort of the superpower of being

the mathematician, right? You're not constrained. And non-Euclidean geometry was discovered before it was, well, I say before it was used in physics, but if you're doing things on a sphere, that's fine. But before all of the relativity stuff that really made it come to that. Of course. Right. But this back and forth where you can have something that at

one moment feels discovered and this awe-inspiring truth, and at another moment feels like it was just baked into the definitions, this is a very long-winded way of answering the simple question that you asked, is math invented or discovered, for how I like to think about it. It is both, but more specifically, I think you go out and you discover stuff based on your existing, either your world or your existing math. You use those discoveries to inform the definitions of the next step, and then you make more discoveries in that next step. And then you use those discoveries to inform the definitions further on. So basically what you're saying is math is discovered the way Columbus discovered America. That's basic.

What if we define it as the West Indies? I'm Jasmine Wilson and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson. Grant, you have a perspective on education that I highly respect. Even if I don't agree with every bit of it, I deeply respect it. And you part ways with many educators in that you don't necessarily prioritize. I don't want to put words in your mouth, so correct me if I misrepresent this. You don't put as a priority, you should learn math because it's relevant to your life. That's a typical way a math teacher would approach it,

worried that if they teach math and it's not relevant to people's lives, they will just ignore it, get bored, go to sleep. So I have two questions for you. One, we probably agree that math more than any other subject is what people say is their hardest subject. So how do you get around that if not by making it relevant to people's lives? So first of all, I think anytime there's a discussion of education, we should pair out the idea that explanation is different from education. And the idea of like making a YouTube video or making an explainer is a very different task from being an educator in a classroom, eliciting something from a student and that

you're playing different games then, which is relevant to the answers here, I think. Because if relevance is on the table, it's within, you know within one hour from being able to explain why this piece of math actually touches someone's life. Amazing. Run with that. That's the most inspiring thing, if someone can see how it's useful for them. I have all sorts of friends who hated math. I lived in the Bay Area for a while, lots of programmers there. And they came to love math through programming. Because they were into computer science, they saw that, hey, to do this graphics project, I guess I really need to understand matrices. You also studied computer science as

well. I did. And so, yeah, so a lot of my like social circles are in those spheres. And, and so that's a story I've seen many times where here's this, this bit where usefulness is what, what made someone finally like it. That's great. But I think very often utility is just not on the table for a given piece of math all that soon. You want to teach some high schooler about the quadratic formula and they say, when am I ever going to use the honest answer for that student? Is never times out of 10. Never, never. Like you might not just never, never, ever. Okay. Well, I made a mistake once I was uh giving a talk to pixar and i use this as an example like the quadratic formula you'll never use it so we have to like motivate in these other

ways and then afterwards all these graphics programmers come up they're like we use it every day they're like it was used approximately a trillion times to produce the movie coco and i'm like okay okay fine like yes it can yeah yeah To be careful what you say to Pixar people, there's some, there's some mathematically and scientifically literate folks. Seriously. Yes. But yeah. So given for most people, never, they're never going to use it. Then you say like, why learn it? And you could say it's simply not worth learning, right? You know, spend your time learning other things, but there's, there's something about the mental exercise of rigorous thinking that is so pure in a mathematical setting that it really flexes some muscles that are going to be useful elsewhere.

Mathematician, go on. Okay, yeah, no, it's self-serving. But I think the better analogy, if you want to tell a student why should they learn this, it's like if you go to a football player and they're in the gym and they're doing some squats and you say, you're never going to be on the field with like, you know, 400 pounds on your shoulders that you're like lifting in this particular way. Like, no, no, no, it's building muscles. Um, and so I think a lot of the math that we do in school, it's, it's the same motivation. You're saying, no, no, no, you're not going to use like this particular thing in the same way that out on the field,

you're not going to be doing like a literal squat but the muscles built doing it like really do make you more powerful later that also math can and i think often should be taught as an art simply because it's available and like if you can get someone bought into the beauty of it that is as inspiring if not more so than the utility and often done right it's more on the table than the utility is given the constraint of say like a 20 minute online explainer or just to be clear, I've seen some ugly math in my day. Put it out there. I've seen some ugly paintings too.

Right. But that doesn't mean we can't. So, so tell me is, would you count information theory as mathematics 100 yeah and what makes it so well part of it's what i'm saying it's something we can describe very exactly oh that's as we started this conversation the precision calculation is what you value here so you use information theory i've been told to help people in verbal.

How does that work? Well, first of all, for those of you who don't know, not saying that it's me, but what is information theory? Okay, sure, for sure. For everyone else, Chuck. Yeah, I mean, for all the people out there that are listening right now, like, what do you mean, information theory? So I will answer that question, Chuck, by way of talking about this project Neil referenced, where back in, I think it was 2022, whenever Wordle became incredibly viral on the English-speaking internet, this is one time when I got sucked in just as a programming project to say, like, how would you write a bot that plays Wordle? Because it's so clearly something that a bot could play, but it's just a fun programming project to say, how would you write a bot that plays Wordle? Because it's so clearly something that a bot could play, but it's just a fun programming exercise to do it.

And as I was doing it, I thought it was actually a really nice motivating example to explain information theory to the general public. Because here you've got this game that a lot of people like. The first thought that I had for how to go about it involved these ideas from information theory. I said, oh, this can help motivate. So to answer your question, Chuck, often if you have a situation where you're playing Wordle, and let's say you want to know, is it better to play as a first word? So the nature of this game, you get some letters. If those letters are part of the true word, the secret word you're trying to get, they'll show up yellow if they're there, but in the wrong spot, they show up green if they're there, but in the right spot. So it's this game of like using your previous guesses to get more information about what the true word might be. And there's that

word information. And, uh, so the, the worst, the worst starting example, um, that you could use is the word kayak. K-A-Y-A-K. In some very exact sense, this is the worst starting guess. Yeah, I'm already seeing it right now. That's a suck-ass word for what you just described. Those rules you just described, that is like the worst word. Because it's like, what are the odds there's a Y in the word? It's like, not very likely. What are the odds that a K is in the word?

Not very likely. You're not hitting that many vowels. So you have this sense that you're not learning that much about the word. By the way, the valuation of Scrabble letters tracks this very much. Yeah. Right? Because the rarer letters have higher value. Makes sense.

Okay. Okay, go ahead. I think we use this word information in a very heuristic sense, where it's the idea like, I learn a lot from doing something versus I don't learn a lot. But who made it actually rigorous was a very clever guy named Claude Shannon, who was working at Bell Labs. And this is around 1930s, 1940s. You know, you've got all of these games to try to send information across a telephone line, like if you're talking to someone, but sometimes it's noisy. And so you might ask, oh, should we like boost the signal? Should we add more lines? Like, how can you think more systematically about how well you can

communicate? And so he wrote this paper that's like the seminal paper for what's now known as information theory. He was the first one to use the word bit in this paper. So this was the first time that bits as a concept ever came up. And the basic idea there was like, if you, let's say there's something where there's two ways that it might go, you flip a coin, it might be heads or it might be tails. As soon as you see the results, you've learned something about like which path the universe took. And if there was only two possibilities, you know, that he said, you've learned the unit of information here is one bit, but let's say there was like a hundred possibilities and you learn a specific one of those. Somehow it feels like you've gained more information. And he came up with a formula for quantifying this. And then

he used that formula and like relatives of it to try to describe how much signal you can send across something that has a certain amount of noise. And it made it such that there was a theoretical limit where you could say, this is how much information we could try to get across. And then cleverer and cleverer coding schemes could try to reach that limit. Now, in the context of Wordle, this means that you can put a number to basically how good a starting guess is based on the Shannon entropy is a fancy word for it. But basically, on average, how much information do you expect to get from it?

Kayak has a terrible Shannon entropy in this context. A word like slate is actually very good. It's got that E, it's got that A, L and T are very common letters. S, even if it's not going to show up at the end, is still a very common letter. And so I basically made this video that was giving a walkthrough

of using information theory type concepts and trying to motivate what those concepts were as a way of pursuing this little hobbyist game of writing a plot to play Wordle. Here's one that you don't really hear much, but it's so important. And that would be the central limit theorem. So the central limit theorem is actually as important for why it's like overused and like perceived to be more useful than it is, than it is for its utility. But, um, there's a lot of things in the world that seem to be distributed according to a certain normal curve. And here's what I mean by that. They don't seem to be, they are right. What do you mean seem to be?

Well, actually, actually, no, this is, this is a good fodder for discussion. Let's take heights, human heights. Um, because I think this is a little bit in dispute. So if you go and measure a whole bunch of people's heights, you measure my height, your height, a thousand other people, a million other people, and you create a plot where you bucket it maybe by the inch or something. So everyone who's between 5'9 and 5'10 falls in one bucket. Everyone between 5'10, 5'11, another bucket. You do this for people in the same demographic, let's say, so we'll separate men and women,

we'll same country. You notice that there's this shape that kind of bulges in the middle and it tapers out on either side. And you do this for all sorts of other statistics. And you see the same shape that seems to bulge in the middle and taper on either side. And it's not just that, you know, there's lots of shapes that could kind of bulge in the middle and taper on either sides, but there's a very precise function that you can use that seems that describes this really quite well, even in all these different situations. Got this funny formula. It looks like e to the negative x squared with some constants thrown in. predictions like saying, Hey, how many people, what percentage of people do you think would be taller than six, four, or what percentage of males would be, you know, shorter than five, two, and all of these sorts of questions. So the central limit theorem explains why this curve

and not any other curve, like why this curve comes up. And just as importantly, it explains when, when it's actually going to come up as opposed to maybe, um, false cousins of it that seem to kind of look like it because the way that it'll happen is if you have a lot of different events that you're kind of adding together in some way. So the, the, the pristine platonic example, uh, for a, um, a normal distribution would be something like this. Let's say you and I stand outside and we're going to play this game where you flip a coin and when it's heads, you take a step forward. When it's tails, you take a step back. So you flip a coin, maybe take a step forward, flip a coin, take another step. And you play this game, not just with yourself, but with 10,000 of your friends.

So you're all flipping your own coins each time. Half of you take a step forward, half of you take a step back roughly. And you flip, I don't know, 15 times. So you're all stepping. Some of you got very, very lucky and took 15 steps forward. A more typical person, you know, maybe they took like seven steps forward and eight steps back. But then if you look at where everyone is, that will follow a normal distribution very, very perfectly or really, really closely. And it's because you have this idea that you took a certain kind of random event, flipping the coin, and you were adding the results many different times. And critically,

all of those events were independent. Each coin flip didn't influence the next one. Whenever you have this, a bunch of independent things that you're adding together, it's not obvious at all that that will always tend towards the same universal shape. And it didn't have to be a coin flip. It could have been any other random process with its own little internal distribution. And you always get this idea that adding up a bunch of random things, which are all independent from each other,

lands you on this universal shape. Now, the reason I was saying seems to and waffling a little bit there is I do think that there's a lot of times in statistics when people will assume something's normal when it's actually not or normally distributed yeah yeah like because i assume chuck is normal but i i question you're the only one that's why what do you say assume something that it would follow a normal distribution yeah especially when it comes to long tail events yeah i to ask you real quick before you go forward, because when I'm thinking of this and picturing it, it almost kind of makes sense, the distribution, because you're only talking about a coin flip, a coin flip.

But you said any random. So let's take 10 white marbles and put them in a bag and one black marble and put them in a bag. And these people play the exact same game with the same number of picks you're telling me that that same distribution is going to be represented the same way i mean if it's not a 50 50 right so um yeah this is good to be more precise so let's say you you pick out very often you're picking the white marble uh one in 11 times you're picking that black marble you play this game they they make 20 picks. They're all independent from each other. You will still see a normal distribution.

What will be different? The mean will be different. So everyone will have taken many more steps forward than back. So they're definitely going to be shifted up the road. Just to be clear, everyone, he's a mathematician. He used the word mean. He means average. Okay.

The average, yeah, yeah. Their average position will be different. We have a mathematician in the house. Yeah, the standard deviation it's not the stern distribution just like get up you take a step i'm the mean distribution take a step damn it you loser no it's actually it's a very insightful question it's a very insightful question because it gets at a thing that I didn't mention, which is how like, okay, it's not literally the same distribution where they're in the same point in space, but they'll be shifted up the road. They might be like spread out a little bit more.

However, the, this curvy shape that you draw on top of it, that has a very specific function that's E to the negative X squared. That's not an arbitrary function that with a couple parameters you tweak that just tells you like, where is it center, how much is it spread out, just two different parameters, it'll still match that. That's the real surprise of it.

It's like, of course some things are going to change. Like, where's the center? Of course the spread is going to change. But the surprise is like, that's the only thing. Somehow everything else that's interesting about the specific ball and bag example you did, that gets washed away. And by the way, the fluctuations in the cosmic microwave background in the early universe between hot and cold around the average is exactly this distribution, which gives us information of what happened way back earlier at the Big Bang, the quantum fluctuations that would have led to it.

Very powerful means of an l average number of prime factors you take some giant number and you ask like how many prime factors does it have and you average that for a bunch of giant numbers normally distributed it's just it shows up in all these different spooky spooky how much yeah yeah it's spooky yeah but also i think there's the regression to the mean for things where you have two smart people and they're smart because of some combination of whatever happened in their life. And then they have babies. It's not likely that the smart that their baby will be as smart as they are because there'll be regression back to the mean of everybody else where. So it works its way in biology.

That's what I'm saying. Are you trying to create a depiction where I'm the baby here? What's happening? No. One more thing before we go to Q&A. Why don't we give a shout out to Fractals here.

Tell me about a Mandelbrot set. Love me a good Mandelbrot set. This is one of those images that really captures the public. Don't be told without one. Let me just say, in all my years of StarTalk, that was the geekiest thing ever said. What? Love me a good Mandelbrot set.

Am I wrong? No. Go ahead. Oh, man. It depends on how much detail you want here. The one version of this is to simply tell people, go to YouTube and search like Mandelbrot set deep zoom, and then simply look and gawk at the shape. And I think this is the way a lot of people engage with it. It's a really, really intricate shape that no matter how far you zoom in, there's always more detail to be found. And that's cool in its own right. What's cool from the mathematician's perspective is that it has a really, really simple rule that was used to describe it, even though it's producing this

mind-bogglingly complicated shape. And that rule is basically... Stop me again if this is too boring or too much detail. the the heavy lift here is that you have to start by talking about complex numbers which is one of those terms that like sounds more complicated than it is because they literally use the word complex but in the same way that numbers we usually think of as being on a number line there's a really natural way of having numbers that live in two dimensions so you choose a point on two-dimensional space and there's a number associated with it and you can do things like multiply it by itself and add numbers to it.

Do normal math operations. Normal math, normal math. And so you start with some point, and you basically say, all right, I'm going to call that point C as my constant C. And then I'm going to play this game where I start at zero,

and I'm always going to take the square of what I have and add C. So for example, you start zero squared is zero, and then you add C and you get to C. You're like, great. I'm going to do that again. I'm going to square the number, which is C squared. So if C was one, you would have one squared. And then you add C to it. So you have like two. And you play this simple game where it's almost like you're at a calculator and you're just pressing the button enter over and over and over having done something like what happens if I repeat this operation? Sometimes the process blows up to infinity. Sometimes it seems to stay bounded and bounce around. If you color each point on the plane based on which of those two things happens,

you color it black. If it doesn't ever run to infinity, it's just kind of bounces around a whole bunch. And you color it some other color. it goes off to infinity. You maybe even give it a hue based on how quickly it runs to infinity. That simple set of rules, which you can write with like three lines in any programming language, that very simple set of rules produces this mind-bogglingly intricate shape. And it shows how complexity doesn't have to emerge from complex rules. It's possible for complex phenomena to emerge from very, very simple rules. And I think that's a powerful idea. And by the way, Mandelbrot is a modern person, right? When was he born and died?

When was he born? In my mind, yeah, 20th century. I think of Mandelbrot as like 70s is when I think of him. Yeah, yeah. He worked at IBM, I think. His first name was ben benoit benoit mandelbrot so i just found out when mandelbrot lived born 1924 died 2010 wow yes a man of our times there yes indeed very cool and so as you zoom in you see new detail that is informed by the previous detail you just

saw but on a smaller and smaller and it's that all the way down well that's that's the very classic famous depiction of a fractal yes it's it's the it's the celebrity fractal you know this is just the you know the a-list actor fractal that everyone wants to call in if you're thinking of a fractal but but since it can be defined so simply the complexity is only what it looks like but in terms of information theory there's very little information associated with it because i remember because i was active in this space briefly and people wondered can we use fractals to represent trees in an image from space if we're going to model what we forest versus land you know uh non-arable land and then some of that was abandoned if not all of it because nature actually has more detail than the fractal so the fractal is like a the lazy way to look like make it look like it has detail which people do this in computer graphics too

they'll use fractals and fractal ideas to give something make it look like nature without having to use a lot of computer to actually to do it okay yeah now you have to hear my, my, my Mandelbrot joke. Okay. Tell me your joke. Okay. You probably know it. So just, Hey, what is Benoit Mandelbrot's middle name? I have heard this one. So, all right, go ahead. Benoit Mandelbrot. Of course. Okay. I have not heard that. Of course I have not heard that.

That's good. That's good. That's good. Can I correct? I'm going to be that guy. Oh, so you're correcting me. Did I misremember it? Go on. Go on.

Well, that's Averitt. The version that I know that I think holds a little better, his middle initial is B, so everyone refers to him as Benoit B. Mandelbrot. And then you're answering this like, hey, what does that B stand for? Well, it stands for Benoit B. Mandelbrot. Oh, gotcha. So then you're constantly filling in the B, what does that B stand for? Well, it stands for Benoit B Mandelbrot. Oh, gotcha. So then you're constantly filling in the B.

Okay. You got it. That's the foot. Thank you. I, I shortened it because my memory didn't hold this whole joke. I'm just going to let you know, um,

uh, as the resident lay person here, uh, and a comedian, uh, it's not funny. Okay. So, uh, person here and a comedian. It's not funny. Okay. So

no, I'm joking. Joking. so chuck you got some questions from our patreon supporters who have exclusive access to our question flow so what do you have for our guest today by the way you might be our very first mathematician guest i'm almost embarrassed to say that i i feel a little bit of um hesitation with the word mathematician because i don't i'm not a research mathematician um i often like hold that in a certain high esteem okay okay so i'll reword it out of respect for your concern to not oversell yourself okay you might be the first person we've had that truly loves math. Okay. Yeah.

You know, Brian green is going to be very upset with you for that statement. Oh, that's true. Okay, man. Yeah. But he,

I wouldn't call him a physicist there. He is a physicist. So no matter what. Okay. All right, let's go. And by the way, if you are a Patreon patron, we thank you very much. Yes, thank you.

Let's go to... Hello, Dr. Tyson, Mr. Sanderson, Lord Nice. This is Hugo Dart from Rio de Janeiro, Brazil. With my six-year-old daughter, Olivia, we are such huge fans of StarTalk. Mr. Sanderson,

what new possibilities does the evolution of AI present to the visual representation of mathematical concepts? Is there a revolution in the area taking place or about to take place? What do you know? Thank you. So is AI touching math? Is that basically that question? Yeah, it is in some pretty interesting ways. So a couple of different

avenues. One of them is using AI to suss out conjectures, things that you look at a bunch of data about something mathematical. And a lot of times when humans come up with conjectures, which are guesses about what might be true that they have yet to prove, they just use their instincts. They say, it seems like this might be true. Maybe I should try to prove it. And so there was some work with DeepMind where they essentially had some computers try to generate what's the interesting math. DeepMind is Google, correct? That's Google. Yeah. Yeah. And so that's one avenue. There's this other avenue where math lends itself to exactness, like we've been describing, in a way that also lends itself to computers very well. And so this phenomena emerging really in kind of the last decade is a notion of proof-checking

software, where when you write a theorem, rather than writing it in English, you write it in an actual programming language that can check for sure if the thing is true. And so, for example, I get a lot of, like, both real mathematicians and me will get emails from people claiming to have proven some famous unsolved problem and the normal thing to do with the emails is just ignore them because like this is not the normal way that like a real proof would would get surfaced but proof checking software would mean that you can basically say hey if this is an actual proof write it up in the software we'll just run the software if it checks, then we know it's worth looking into. But this interfaces with AI in an interesting way, where if you want to teach an AI to do math, you can just generate a whole bunch of proofs automatically, whatever you write it in this

special software. And whenever it compiles, whenever the software checks out, you know it's valid. And then you have these AI reinforcement learn on the ones that are true, kind of like when they play chess against themselves or play a game against themselves to get better by doing it trillions and trillions of iterations. You can do this with math in a way you can't do with other fields. And so there's this thing called the International Math Olympiad, which is, I went to it this year. It's great fun. Every country sends six high school age students to basically. But you went to it not as a contestant.

No, no, no. It's for high school students. I was about to say, you look to it not as a contest no i was i was i was giving some lectures to the students um but uh the uh this was one of the first years that um some companies had bots try to answer the questions these are quite hard questions they they're written proofs they're They're not just like enter a number kind of thing. And the AI, again, DeepMind was doing it, that they developed, got a score that's equivalent to getting a silver medal at this International Math Olympiad. And people didn't think this would be possible because it's considered like such a, it requires creative thinking. It's not just rote mechanics. And so seeing this level of creativity. The reason that was possible is because they could do this game

of letting a computer play against itself, in a sense, using these sorts of proof-checking softwares. So short answer to our friend from Rio de Janeiro, I was like, yeah, there's lots of interesting interface with AI and math. Corey He, who says, hello, Dr. Tyson and Mr. Sanderson.

Sorry, Chuck, I don't like you, so I'm not mentioning you. I put that in there because he didn't mention me. This is Corey He from San Bruno, California. We use base 10, and it still leaves us with a lot of irrational numbers. Is there a number system that would make irrational numbers, such as pi, rational? So, first of all, I used to live in San Bruno, so hello, Corey. Oh, really? Get up.

So one answer to this question is, no, whether a number is rational or irrational has nothing to do with how you represent it. This kind of cuts to our alien discussion earlier. No matter what language we're using using what base system we're using the idea of what makes a number irrational irrational it's intrinsic to the number itself so it's it's a property not of the of the description but of the of the number itself um but maybe when i just look this in here just because you have to help me out. Pi, which is irrational and transcendental, in base pi would be 10, 1, 0. So what's irrational about 1, 0?

The word rational will mean you can represent as a fraction of whole numbers. So the counting numbers, 1, 2, 3, 4. If you can represent something as a fraction of those so in base pi all of the counting numbers which are pretty natural object you're just counting rocks out in the world would have these these wild descriptions that take a whole bunch of different we wouldn't call them digits it'll force everything else into a weird weird state also it's it's not clearly well defined what it means to be base pi because like what are the symbols you use with base 10 you have 10 symbols that you're using to represent with base 4 you have four symbols that you're using but base pi like what it's not entirely

clear what a non-whole number it's one symbol it's one symbol but it goes on forever forever okay so you're right if you make pi a nice even looking number everything else relative to it has to has to die give it give of its smooth life for you to make pi look smooth you can make it represent yeah it's the the the thing that's irrational you could say is the relationship between pi and the number one. So it's kind of like whichever one of those you make look as natural as you can. You have to own up to the fact that the relationship between the two has this property of not being rational. So the answer is no. No, the answer is no. know that you know basically you you're not going to be able to make pi rational without making everything else you know some kind of weird representation like that can i add on is rational

but go ahead i have a tendency to blather so definitely stop me if i go too deep now aside from talking about bases you can talk about how do you represent irrational numbers where we what we're used to do is writing them down with decimals like pi is 3.1415 which effectively you're saying it's three and it's plus one tenth plus four one hundredths plus one one thousandth you're kind of adding all these like powers of 100 but there's other ways that you could try to use numbers to represent irrational like use whole numbers counting numbers to represent irrational values. I just want to throw into the ether for the curious listener to go off

and land on the Wikipedia page if they want is the idea of a continued fraction where it's another way that you can use a sequence of numbers, of counting numbers to describe these irrational things. I've had nightmares about continued fractions. What can maybe turn those nightmares into dreams is seeing how certain values like the golden ratio or E, when you look at their

continued fraction, rather than just having a whole bunch of arbitrary seeming gobbledygook as the digits, you see these really, really natural sequences. And so somehow if you want a different language with which to describe numbers like continued fractions offers another language that exposes the regularity in certain irrational constants even if the fact that they're irrational is something you can't see now this kind of this kind of strikes me as uh what we talked about in the beginning of the conversation as useless math you know what gave me nightmares is you write it but you can't write the whole thing it's this fraction that just spills off the page but the same is true of um of decimal values like i can't write pi 3.1415 still not pi 3..1415. So you're saying if I'm okay with that, I should be okay with continued fractions.

I don't know. I mean, they're awkward, like the layout. Cause you have to use vertical space to kind of like, right. Right. And it grows as you keep going.

Yeah. So I, I think we need a representation of irrational numbers where the numbers don't believe that the earth is round. Okay. That's for sure. Yeah. All right.

Time for a few more questions. All right, here we go. This is Alyssa Feldhaus from rocket city Huntsville. And, uh, she says, is there black hole math that we may be missing to see what the end result

is beyond the event horizon? So I like that. So let me flesh that out even some more. The limits of our theories of the universe, so general relativity, has limits that are known in advance. It cannot describe the singularity of the black hole or the singularity of the Big Bang. And these are gravitational singularities where it has been said, God divides by zero, which you're not supposed to do.

So is, and then strength theorists march to the rescue, except they haven't rescued anything yet. So at what point do we say grant that we're missing physics new physics to help us and at what point might we say come on guys give us another branch of mathematics and that will save us from our ignorance now is that a fair retelling of this question i I think it might be. I like that retelling. I'm going to throw out a flag that feels like this one's a little above my pay grade in terms of, like, I know a lot of the specific insights around understanding what happens at the event horizon have been, you know, this has been one of the most fruitful areas for seeing relationships between quantum mechanics and general relativity. fruitful areas for seeing relationships between quantum mechanics and general relativity.

And the specifics of that, I'm not going to pretend to have my mind fully wrapped around to say like, ah, here's what the insight will be that gets us one step further. But maybe Neil, you can provide a little bit of intuition on this where I think broadly the idea of alternate mathematical tools to understand like that specific part of the universe feels like a ripe area for um for where progress can happen where a lot of new physics happens at the boundary of what uh of what we can observe and have observed and you know singularities give something that's quite literally at this boundary and And so I think in history, when you have had new types of math come in to describe new physics, or it can even be old math that's describing new physics, right? Like when quantum mechanics was founded and people started using a bunch of matrix algebra to do

this, it's not like matrices hadn't existed. It's just there was a utility for them that hadn't been known before. Same deal with imaginary numbers in quantum mechanics. They had existed, but there was a utility that was then found. Similar things might happen for whatever further steps one wants to make here, where there might be

some existing math out there that hasn't yet found a utility, but you try to use it. We'll get back to work so you can help us out. Yeah, yeah, exactly. Chuck, got time for just one more question.

Just one more? All right. How about frosty from tennessee you don't know how he speaks what's that you don't know if he's got that accent uh no i don't but he does now i'm frosty from tennessee i guess with a name like frosty he's got it coming yo that's man. Frosty's cool. Never mind. Anyway, he says many mathematicians speak of the beauty in mathematics. How would you explain this beauty to someone who might view math as purely functional or just plain difficult? And I'd like to add to that, do you have any insights into why so many people find math to be difficult? It's almost like all of civilization, there are

people who like math, and that's 1% of everybody. And then the 99% of people who hate math, was they worth subject? They never did well in it, and then it was never intuitive to them. where they never did well in it and then it was never intuitive to them. As an educator in that space, take it on. I think a lot of what's happening is that the things that we do in school are pretty distinct from what mathematicians find beautiful when they're referencing that.

So it's not that they're both looking at the same thing and one type of person finds it beautiful and then 99% don't. We're looking at different things because in school, often what you're doing is implementing like a procedure. You learn the procedure for adding two digit numbers. When you're like in elementary school, you learn the procedure for solving for X. You learn the procedure for taking a derivative all of these times along.

The thing that people find beautiful, all these different levels, whether it's at the elementary or, you know, the usually calculus is like the highest one that a high school might teach all of it. It's still very procedural. And that's, there's nothing wrong with that. Like that's a necessary part of doing that. That's, that's where you're doing your squats in the gym, right? This is building some muscles, but the, the thing that is beautiful will be unexpected connections. So seeing like, Hey, I saw this bit of math show up off in this corner. And that same bit of math showed up in this completely different spot. Um, I mean, pie is a really good example here where pie shows up in all sorts of

places you wouldn't expect it to. So just, I can throw down one very quick example, um, for the, something that maybe anyone can understand why it's at least surprising, even if maybe you don't see beauty in it right away. If I take one minus a third, you end up at somewhere on the number line. And if I add one fifth, you kind of go up a little bit. And if I subtract one seventh, and then I add one ninth, and I subtract one 11th, and I add one 13th. And I play this game of basically adding and subtracting in alternating fashion, all of these like one over some odd number. Ever smaller and ever smaller. It kind of bounces back and forth and it seems it'll approach one particular point on the number

line. That point is exactly pi divided by four. I mean, look at that. Pi is about circles. Why on earth would pi have anything to do with this game that I'm playing? It's got no business showing up on your timeline.'s got no business on your number line there's so many the normal distribution we were talking about earlier that describes you know statistics all over it has a pie in it when you describe the distribution properly why where's the circle what on earth is going on there so that that side of it where there's a mystery there's this it's you know it's it's the opening chapter of a mystery novel you You see this thing, you want to know like, who did it? Like, why did this happen? And then, and then the path to resolution. But I think the, if anyone enjoys

a Sherlock Holmes story, for example, the part of your brain that that's tickling, where you have this mystery at the start, some path that feels like it could be discoverable, but takes a little bit of cleverness along the way. And then it's satisfying to see the knot tied at the start, some path that feels like it could be discoverable, but takes a little bit of cleverness along the way. And then it's satisfying to see the knot tied at the end. Like that is the feeling that people are describing when it's the beauty of math, which is different from the thing happening in most classrooms, which is the procedural side

and understanding how to go through motions, which are useful, right? But it's just, it's a different category. Well, Grant, you're giving us hope. Yeah. Because people do like connections. I mean, there's that whole TV series and book series. Who's the host of that?

The British guy. Yeah, yeah, James Burke. Right. It was about connections. And of course, there were geopolitical, social, cultural connections. But nonetheless, I think we always like knowing that this over here is the same as that over there. And when you didn't otherwise realize that. But I think the intrigue that you're speaking to is far more important from an educational

standpoint, because the procedure is kind of the work, the nuts and bolts, whereas what you are speaking to is the wonder and the mystery. And these are all concepts that show up in life throughout life, and that always spark us to think and to ponder and to something bigger than ourselves. And if people were able to bring that into the classroom, I think you would find a lot more children being excited about math. Not all educators are made the same. That's the problem. Yeah.

I mean, honestly, I'm always fascinated when I listen to anyone talk about math, from Neil to you to you name it, to Brian Green to Brian Cox. The way you talk about math makes it so much more interesting. But when I was in school, I had several teachers, especially in calculus, where I would get the right answer, but I got it the wrong way. And that was the end of it. They were like, yeah, you're wrong. You can't do it like that. end of it. They were like, yeah, you're wrong. You can't do it like that. And I'm like, okay,

well, instead of, hey, let's go on this little journey to show you how you're thinking about this. I never got that. It was like, no, you got the wrong answer. And honestly, it only took a little, I was like, clearly I don't think right. That's when I came away from calculus. My calculus experience was I do not think right. And that was it. It's your problem. It's all you. So Grant, thank you for being a guest on StarTalk. And once again, we can find you on all platforms with three blue, one brown as the handle. And I don't think you had to compete with anyone to get that handle on all platforms

as you have successfully managed. And you have a podcast, YouTube channel, a blog. You, you're active on, uh, X and,

and Instagram, Instagram as well. Correct. Yeah. There's some short videos, um, up on there. Yeah.

Your YouTube is chock full of all manner of videos, some short, some long, some courses you even give there. And they're so popular. And it gives us hope that not everyone in the world thinks of math as the worst possible thing they could give their brain attention to. And you are living evidence of this. So, Grant, thanks for being on StarTalk. Thanks for having me.

All right, Chuck. Always good, man. Find you, Chuck. Nice comic? Chuck, nice comic everywhere. Thank you, Neil. Everywhere. You got a comic C-O-M-I-C. This has been StarTalk, a hybridized Cosmic Queries all about math. Neil deGrasse Tyson here. As always, I bid you to keep looking up.