What Everyone Knows You Know with Steven Pinker

Finally got Stephen Pinker! I know! Okay! Yes, we're gonna learn all about how the brain is messed up. We don't need him for that. Ah! Come on up. The latest from the mind of Stephen Pinker on StarTalk. StarTalk Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now. StarTalk This is StarTalk. Special edition. Neil the Grass Tyson here, you're a personal astrophysicist. And when you hear special edition, that means we have Gary in the house. Hey Neil. How you doing Gary? I'm good. Chuckie baby. That's right. How you doing man? I'm doing great. So today, we're talking about common knowledge. Yes. Common knowledge. Uh huh. But why is that interesting? If we think about it, we humans have evolved to be social creatures. And we rely upon each other for many things. We use language to communicate and coordinate ourselves. But do we consciously strategize in our social behaviour? And are we aware of our own signaling when we interact? And to the point, what role does common knowledge play in our everyday lives? I mean, I depend on that all the time, just as an educator. Fine, but a lot of people won't realise that it is something they're using as a tool. Some people will, as you do. And does it then play a role in the big ticket items like financial crashes or political revolutions? Now, okay, I can drone on. I've said enough. Let's introduce, I guess. You're going to, we're going to connect common knowledge to revolutions. Let's see. Okay. Okay. We've got the world's expert on that topic. Yes. Sitting right here. Well, thanks guys. I appreciate that. You know, I remember pan-ladded. Oh, I remember pan-ladded. Stephen Pinker. Oh, we're a Stephen. Stephen Pinker. Welcome to Star Talk. Thank you. My gosh, we go way back. I do. It's decades. I think it's your first time on Star Talk. It's bad oversight on our part because there's no reason for that. You're too active. Your stuff you work on is too interesting to go on this long without you being on. So thank you. Better late. And I just have to ask, up top, are you still winning the best hair for a scientist contest every year? Oh, I don't know if the luxuriant flowing hair club for scientists is still active. That's what it was called. That's what it was called. That's what it was called. That's what it was called. That's what it was called. That means it had no black people in it. I think it did actually. There are some impressive feathers. Oh, dread. You can dread your way in that. There are some pretty amazing afros out there too. Okay. This is a pretty cool club. This is a project of the respected scientific outlet, the journal of irreproducible results. Oh, good. Okay. We should do a whole bunch of shows on them at one point. I mean, you know, Bell prizes. I know, I know, I know, I've never won one. I'm, that's great. So you are cognitive psychologists. I think that's what they call you. Do I remember you being a linguist though, long ago? I'm not a professional linguist, but that was your, I kind of a psycho linguist, which is the psychology of language, which is a branch of cognitive science. So I first met you and knew your, your, your work. But for me, language is just one of the amazing things the human mind does. So I don't, I don't have a PhD in linguistics, but in cognitive psychology. Got it, got it. And I have got you here as the John Stone family professor of psychology at Harvard University. So are you in the famous building, the psychology building there? William James Hall. William James Hall. The 15th story white building. Yeah. Sticking out like a store of sore thumb in a Cambridge residential neighborhood. I got you down here for a dozen books. Several of them are some of my favorite books. You know, the blank slate, which had its own bit of controversy. But it's fun to see an intelligent arguments presented into that space. The better angels of our nature. Oh my gosh. It's very light, yeah. It has the two words common knowledge in the title. In the subtitle. Subtitle. So give me the full up title. So the title of the book is when everyone knows that everyone knows dot, dot, dot. And there's a story behind that. The subtitle is common knowledge and the mysteries of money, power, and everyday life. Whoa. And I can explain. Yeah. All of those things. Leave anything out there. That is. That's a title. That's actually three titles. I mean, I know you're a psychologist, but you've put in mysteries. Yes. There you go. And then money and power. I should have put in sex too. Yes. So you'll get. You're completely manipulating the buyer. Of course, right. Absolutely. Now I want to hear the story behind this title because that's a lot. Okay. So common knowledge in the technical sense refers to the situation where I know something. You know it. I know that you know it. You know that I know it. I know that you know that I know it. I didn't find item. So it's when everyone knows that everyone knows and the dot, dot, dot is essential. I had to fight with my editor. He says, oh, it'll screw up the computer listings. Let's Amazon. That's infinity. That's infinity. Yes. Technically. Technically. You know, the first I saw that was Ralph Kramden in the honeymooners. You know that I know that you know that I know not. Not. Oh my god. I didn't put that in the book. Not. Absolutely. Eddie Murphy. No, no, he's imitating the actual honeymooners right? You know that I know that I know that I can't believe I left that out. Yes. This is my first encounter with the infinity. I got to look that out of the. Yeah. Yeah. That's the original. Then it's definitely Eddie Murphy imitating them. Yes. It's just as good. I've made it better. Yeah. So to be distinguished from private knowledge where everyone knows something, but they may not know that everyone else knows it. And that makes a big difference. It does. Wow. So it's never thought to think about that. It's been explored by game theorists, the branch of mathematics dealing with the best strategy when other people are dealing with have their own strategies. It's a big deal in economics for reasons that we'll get to. It's been studied by philosophers. But it is a psychological phenomenon. It's getting in the heads of other people when they're getting into your heads. Still other people's heads. And there have never been explored from a psychological point of view. Now why is it significant? The reason that it's important is that common knowledge is necessary for coordination. That is for two people being on the same page, doing things that benefit them both as long as each one can expect the other one to do it and expect it. Don't we call it civilization? Well, civilization does depend on. Right. It depends on the reasons like government, like money. The reason that it's in the subtitle is the only reason that a piece of paper with Abraham Lincoln on it is valuable is because other people treated as valuable. Now why did they treat it as valuable? Well, because they know that other people will treat it as valuable. That's what makes it a currency. Likewise for power. There's no way a government can intimidate every last member of its citizenry. And give it time. I'm working on it. I recognize the impression. But the government has power. A president is a president and a governor is a governor and the chairman of the board of the chairman of the board because everyone treats them as if they are. It's a social reality. Our corporations, our religions, our gods, our conventions, even language itself, what makes the word refer to a rose with just a sweet by any other name. Rose means rose because everyone knows it means rose and everyone knows that everyone knows. So all of our conventions, all of our ways of coordinating, all of our harmony depends on common knowledge. Just to give a concrete example from Thomas Shelling, the political scientist and economist who was one of the originators of the concept. Imagine that, say, a husband and wife get lost in Manhattan. This is the era before cell phones. How can they meet up? He can think, well, she likes to go to a bookstore, so I'll meet her there. But then she knows that I like to go to a camera store. So maybe she'll go to the camera store. Then she knows that I know that she likes to go to the bookstore. So she'll go to the bookstore after all. Meanwhile, each of them can ricochet with this useless empathy and still not end up at the same place at the same time. Nothing short of common knowledge, not only knowing something, but knowing that the other person knows that you know, gets them together. Now, common knowledge can be generated by language. That's how I got into it. That is, in this case, a cell phone call. Although it can also just be a convention, something that everyone assumes that just coordinates it. But day of the week do you stay home? Sunday? Why Sunday? Well, because everyone else stays home on Sunday. That's a good reason for me to do it. If everyone else is doing it. So a lot of our society depends on common knowledge. This immediately raises a question. People say, well, you define common knowledge as I know that she knows that I know that she knows that I know that she knows. But no one can keep track of them. That's why you have plots like the Honey Moons or this episode in Friends that people always tell me about where Rachel says, Joey, they don't know that we know that we know that we know. You can't say anything. And she says, I couldn't even if I wanted to. The point being that your head starts to spin when you have to keep track of more than two or three layers if I know that she knows. So how is this possible? Well, the reason it's possible is that we can get common knowledge at a stroke when there is something that we sense to be public or out there or salient or you can't miss it or it's in your face. So if I see something, at the same time as I see you see it, then that implicitly packs into it as many layers as we would ever need. We don't have to think the ball through. But it also means that we're really, really sensitive to something that is public that you can't ignore versus something that may be known privately. And I have chapters in the book on how that shapes our language, why we don't just learn out what we mean, but often they all are intentions in you from this and in you end up to prevent things from being common knowledge, phenomena like being in the closet or for any, whatever is the reason. Well, it used to be, it used to be the gate key for my closet. That's why I was talking about it. Well, my gratitude to you. That's why I was talking about it. Well, my gratitude to a walk in closet. I didn't know that. Very good. That's good. Well, my, my gratitude advisor, actually, he insisted he was not gay. He was a homosexual to be in the day. In the day. In the day. And he said that to be gay, you have to be born in the 50s or later. He was born in the 20s, but no one ever acknowledged that he was gay and he would never acknowledge it. Well, sometimes we describe him as a bachelor. Now, each of us confirmed the bachelor. Confirm the bachelor. Until he was in his late 50s when he finally, as we say, came out. Now, it was the metaphors in the closet means that it's not public. You can't see it. Coming out means not only can you see him, but you know that you can see everyone else seeing him. But that's a good metaphor for common knowledge. And common knowledge in general governs our relationships as well as our institution. So it's not just money and power. The everyday life in the subtitle comes from the fact that our relationships of deference, of intimacy, of friendship, romantic relationships, transactional relationships, they all exist because both parties know they exist. What does it mean to be friends? It's not like you sign a contract. It was an implicit contract in a way. It is implicit. And it's a complex, it depends on common knowledge. Namely, what does it mean for us to be friends? It means that I know that you know there were friends and I know that you know that I know that we're friends. That's all there is to it. And so sometimes when we don't want to threaten a relationship, we might avoid common knowledge by hinting, slipping in our intentions as eating around the bush, euphemism, you kind of catch my drifty, connect the dots, or as if you blurt it out, then that changes the nature of the relationship. Hey, this is Kevin the Somaliyeh. And I support StarTalk on Patreon. We're listening to StarTalk with Neil deGrasse Tyson. So what about those where I'll see the common knowledge, but there is what I'll call an acceptable duplicity. Yeah. A two way duplicity. A two way duplicity. Like we're both aware of it. Yeah. But nobody wants to wear it out. I don't want to upset the Apple Car because what we got here is good. That's exactly what I talk about. We have a chapter called Weasel Words. Weasel Words. Yeah, that sounds like a fun chapter. But acceptable duplicity. I mean, there's all kinds of benign hypocrisy, the politician who resigns to spend more time with his family, the escort services. Would you like to come up for Netflix and chill? Let's say you were trying to bribe a matrede to jump the queue and be seated immediately. You might kind of holding out a $50 bill in peripheral vision, say, is there anything you can do to shorten my wage? I was wondering if you might have a cancellation. Right. I know. $50 cancelation. Right. And not if I give you 50, will you seek me right away? Exactly. Because that would be crass. So what does it mean for it to be crass? What it means is you're disrespecting the relationship you have where he is the authority and he sees you wear when he pleases. You're treating him like a transactional relationship, which is a very different kind of human relationship. That's just a transactional. Likewise, what's the difference between you want to come up for Netflix and chill and you want to come up for sex? Well, with Netflix and chill, there isn't really plausible deniability. I mean, you know, she's grown up. She knows what it means. But she could have some doubt that you know that she knows that you know what it means. And she could think, well, maybe he thinks I'm naive and I'm just turning down an invitation to a movie. And then she can think, well, maybe she thinks I'm dense and that I might think she's naive or I might think that she doesn't realize that I'm not naive. So they can maintain, go back to their platonic relationship. They haven't jumped to the conclusion. Right. Well, it's possible deniability of common knowledge because we think it's really not that plausible. Right. Everybody knows. But like they say, everyone may not know that everyone knows exactly. And what that does is it allows you to save face. It allows. So saving face, by the way, another great going back to the idea, how could, if common knowledge is so important as I say it is, and it requires, I know that she knows which makes your head hurt, how could it work so well? And one of the reasons is that we talk about it, not using the language of philosophy or game theory, but metaphors of something being visible out in the open. That's why we use expressions like in the closet or saving face. Face is a part of you that other people see and that you use to see other people. So saving face or losing face is a great metaphor. That's really saving the facade of your face. Yeah. In a way, right, saving the face that you had established prior. Face and facade are related. I guess so. Listen, do you know in the movie Back to the Future, there's a deleted scene. Which? How could I know that? Oh, sorry. Where the doc is setting up his connection to the clock in anticipation of the lightning strike. Okay. The cop comes by and say, Doc, what you doing? I'm just doing some weather. They'll give me his voice, some weather experiment. I'm doing some weather experiment. Thank you. And then. And so then. And he said, you got a permit for that. And he says, of course I do. Okay. So then he comes down and goes up to this is the deleted scene. He walks up to him, opens his wallet and there's just cash there. Oh my goodness. I just have his permit. I didn't. Oh, I was about to pick. I didn't see that. Yeah. So he bragged him, but that's kind of out of character with how he's just a lot of daughtering old, old scientists. That would have damaged his character. It would have damaged the character. Yeah, that would have damaged the character. But that would have been a perfect example. It's transactional. It's true. Well, the thing is that it's in fact transactional, but it's very dangerous to suggest to a cop that you have a transaction. Right. In fact, it's illegal. It's just makes it visible. Exactly. That's all it is. Somewhere in here. And so, you know, it's not plausibly deniable, but it's deniable that the other person knows that you know or knows that you know that he knows that you know. Right. And that's what flips it from deference and respect and authority to transactional. And you want to avoid that flip, but you still want to do business. That's why they're useful. That's why they're useful. Because I'm from Philly, and it was of course Philadelphia politicians, but I forget the name of the scandal, but it was very famous because they caught it on tape. Only one politician didn't go for it, but these people, these, these feds dressed up as like Saudi businessmen. Oh, and they abscam. Abscam, that's exactly right. Abscam, don't you think? And they had like piles of money like sitting out. That's been done a number of times around the world as they were discussing what they wanted. And then only one of the politicians was just like, yeah, I'm not worried about that. Let's talk about it. And everybody else went down because it was, it was the financial seduction with that work. But they never said this money is yours. They just put a pile of money in front of them. And they were like, so let's talk about the new rail line. You know what, they were more veil bribes. They were broke, okay. They were veil threats. They were like the, I quote an episode from the Sopranos in which a member of the family approaches a high school acquaintance says, hey, great to see you, Danny. I hear you're on the jury for the Sopranos trial. It's an important civic responsibility that we should all take part in. You've got a wife and kids. We know you'll do the right thing. That's a veil bribe. Now of course, bribes are extortion is illegal. Right. In everyday life, there are occasions where there are implicit veil threats that you don't spell out in so many words because that establishes a relationship of dominance. And you may want to avoid that relationship while still getting the message through. That would completely change the dynamic. Yeah. Change the dynamic. Right. That doesn't happen in the black community. It's just like, I will kick your ass. It's resolved in the moment. It's resolved in the moment. What? I will kick your ass. No. Well, there are. I mean, so that's a case where the relationship of dominance is already established. Domestic. That's the exact scene in coming to America. Is it? Where? Where they're at the McDowell's home and the king says, how much for your daughter? Oh, okay. Yeah. This is America, Jack. You better stop me before I put my foot up your ass. Right. Because that John A.M. is the same thing. Yeah, yeah, yeah, yeah. I forget the exact words. In the moment. Right. It was a king and just like a rich American. And a rich American. Another great example. So, why do cultures differ from each other? Well, there are, if you think of the different kinds of relationships. So the basic kinds of relationships are communal sharing, warmth, intimacy. That's one model. Not America. Not America. Another model is what's mine is mine. And what's yours is mine. And then that's, there's actually twist on that. So another relationship is hierarchy. You know, alpha male, pecking order, top dog. And the third one is transactional. Now, where culture is differed is not across the board. But in what kind of relationships, parent, child, student, teacher, employee, boss, friend, resource, money, favors, sex, and what context, home, school, public. If you mix and match those, that's gives you kind of all the variation from anthra 101. And so there's certain resource. So for example, there are cultures that really openly trade brides or, you know, daughters to become brides. And there's doesn't commoditize that explicitly. But we do say by and sell land, which some cultures don't do with land might be communal. And so if you think of all the resources, all the contexts, although the, the, the, the matrix of, that's the matrix of anthra 101. So if we look at common knowledge as a variant of culture and different cultures, prize certain common knowledge differently, how often do we get the misinterpretation of our common knowledge? And get misinterpretations when they're cross cultural, exactly. Yeah. And that's part of what culture shock is. You don't know what are they, what is the common knowledge in the new community that you have to deal with. And that can result in war. It could result in war. I mean, it can result in misunderstanding. Sometimes comical ones and it's used in comedy as in coming to America, as in Borat. We have the bumpkin from one culture using the assumptions that were native to that guy's culture, but completely inappropriate, sometimes leading to embarrassment, sometimes to shock and outrage. Yeah. And then if we look at the communication through body language or unintentional signalling. Yeah. So there's a, I have a, a chapter called laughing, crying, blushing, staring, glaring, about nonverbal common knowledge. Couldn't get a long title then. Laughing, crying, blushing, staring, glaring, glaring. Glaring, okay. Now we have dozens, maybe hundreds of facial expressions, smiling and frowning and grimacing and so on. But on top of that, we have some really conspicuous forms of nonverbal communication that have puzzled people for millennia, such as laughing. Why do we interrupt our speech with the staccato noise? Yes, even more. But it never asks, he needs to pay his mortgage. Oh, come on. Come on. I forgot. There's a whole profession that depends on this, yes. Yes. So what I argue is that for these conspicuous displays, blushing is enough on why should blood go to your cheeks, crying, why should I shed tears? Why do you shed tears? I suggest that they are common knowledge generators. So when you're laughing, you know you're laughing because your breathing is interrupted. Other people know you're laughing because they can hear it. Other people know that you know, you know that other people know, et cetera. Blushing, you feel the heat of the lead, the inside in your cheeks, knowing that other people can see the change in color from the outside. And they know that you know that you're feeling it. All the more so when they say, you are blushing. I've never had that problem. You've been saying, yes, it's not a black people. That's a question. One point in a million people. It's a lesser, it's a lesser say. Okay. So maybe you can, friends, it's so Darwin worried about this because Darwin was a big proponent of universal emotions. In fact, for him, he had a whole book on it. The expression of the emotions in animals and man. Yes, yes. And in fact, he used it, in fact, as an argument against the kind of the scientific racism of his day, which said the different races were independently evolved or created. What? What are the other? Either one. And he said that the similarity in facial expressions in many other aspects of emotion showed that we all decided pretty recently from a common ancestor. Wow. His data, I mean, he was kind of an invalid, but he corresponded with colonial officers and missionaries and traders all over the world. And he had them, he even questionnaires to ask of their interactions with local people, which they then mailed back to him. So just to be good in context, this is before photography could capture it. Right. I'm just at the dawn of photography, what's that? In fact, his book, this book that we're talking about was the first use of scientific photography. Although not for cross-cultural studies, because the missionaries didn't have cameras out of their fields, but he actually used it to analyze the musculature in facial expressions, including studies where they got a person in a asylum and they shocked the different muscles to see what they did to a facial expression. Wow. That was a bit of a digression. Going back to the question though, do you... Silence all they ever use is electricity on you. Oh, it seems like that's the right. But he asked the question, do dark skinned people blush? And is it detectable? At least the answer from him and the answer that I got from Nina Giblonski, who's an expert on skin color is yes. It may not be... Well, I'm not denying it. I'm just saying it's not an active reference in our comments of people's emotions. But I even cite a Gnayan physician. Gnayan? Gnayan? Yes. Very dark skinned. He said, well, my mother can tell when I'm blushing. It's a change in color. Anyway, the point is that it's a common knowledge generator in that you know that your experience... You know that other people can see you experience, they know that you know you're experiencing it. Tears, you're looking at the world through a scrim of fluid. It blurs your vision. At the same time that other people can see the glistening or the trickle. So again, you know that you're crying. Other people know that you know that they know. And eye contact is the ultimate common knowledge generator. Because you're looking at the part of the person that's looking at the part of you, there's looking at the part of them that's looking at the part of you, you know, add infinite them. You don't have to think about it, add infinite. But what about this very powerful thing? Why should that mean anything other than what it means? Well, Darwin dealt with that in the book where he noted that some facial expressions are vestiges or remnant remnants of facial postures that animals do when they're about to attack or they're defending themselves. So in the case of the fear expression, you noted that if you're likely to be a prey animal or someone who's going to be picked on by the alpha, you've got to open your eyes wide to see where threats might be coming from. If on the other hand, you're the predator or you're the alpha, you want to focus. Exactly. And if you, the remnants of that include, and so the burrowing your brows, which I think narrows the field of vision that may even narrow if the folds of skin actually intrude on the pupils might increase depth of field. Yes, it does. That is, yes, optically. Optically. That's why people, if they don't have their glasses on, they squint. They squint. They squint exactly. They don't even know that they're increasing their depth of field by doing so. They're not actively thinking that they just know they see better. Going back to these nonverbal common knowledge generators, we used them to make something public that formerly was private. That's the common denominator, yes. So in the case of eye contact, now that developed way before we were humans because among primates, eye contact is a threat signal. The dominant stairs at the subordinate who looks away, which is, by the way, also true in humans, the boss doesn't contact people. Don't make eye contact. People would have to hit them. Exactly. That was the first thing I was told when I came to New York City as a kid. We were on this subway and they said, whatever you do, do not make eye contact. Yeah. I said, you looking at me? We looked at it. Exactly. And we looked at it and it was intentional not to make any eye contact. Well, the anthropologist of divorce, you should tell us, class, if two human beings look into each other's eyes anywhere on earth for more than six seconds, then either they're going to have sex or one of them is going to kill the other. That is so true. There you go. Oh my gosh. What a great saying. That is true. It's true. So why is this so uncomfortable? I mean, even, like, I don't mind making eye contact, especially with the person's decent looking. Like, I've got to tell you, when somebody is unattractive, I'm, who is tough. Yeah. I'm just saying it is rough to look at somebody who is not attractive and like maintained eye contact. But prolonged eye contact, and I don't know if it's just me, but I'm just going to put it out there. I'm going to be honest. It gets a little like creeping and uncomfortable. Oh, it absolutely does. Okay. So, and I actually write about this. So what we call eye contact and ordinary conversation is it's a bit of a misnomer. Your eyes kind of dance all over the face. Yeah. You spend a lot of time lip reading, but it's the eyeball to eyeball stare. That's really a potent, which is something different. Now, we're humans. We're not monkeys. We're not gorillas. And so eye contact doesn't have one meaning. I mean, it can be seduction. It can be threat, but more generally, it can be something that formerly was private knowledge is as of this moment common knowledge, which is why we say things like, can you look me in the eye and say that? That's pretty good. It's telling the truth. That's how we use eye contact. It's basically with twerring to interpret so many different things. That's why you get uncomfortable. And why you're, when you're embarrassed, you look down, you look away, you avoid making eye contact. So what laughter does is it makes what used to be private knowledge, common knowledge, where it's some indignity or infirmity or weakness of some of the joke. Now that can be someone that you're trying to bring down. It could be someone you're trying to keep down in aggressive humor. Although it can also, there's also, of course, convivial humor, what we've all been doing, where the signaling is to reinforce the egalitarianism. It's the basis of warmth and friendship because there's always a danger of dominance creeping in. If any two people, one of them is going to be better looking smarter, richer, more powerful, but that's not what you want to do in your friends. When your friends, it's like we are all on the same level. And so by calling attention to some weakness in yourself that you could lord over people, but you don't want to lord over people or vice versa, gentle teasing and joshing that together person accepts, then you're reestablishing the common knowledge that the basis of our relationship is self depreciation. Yes, exactly. So what does one do for is it, whatever the number is, is it one out of ten or one out of six of us who's on the spectrum? Where social cues do not play. Might that be adaptive? Where now you don't know anything about me because my facial expressions are not responding and therefore I'm not revealing my inner secrets to you. Well, there is the, that's survival value. I suspect that's more likely used strategically as in the poker face. That is the poker face where you deliberately hide the tells. I, in a case where you're not in a situation of cooperation, but zero, some competition. Right. Then any tell could be used to your disadvantage. And so he's why I don't play poker-ish because I'm the worst. It's just, oh, just kidding. All right, to go back to briefly. To the enemy saying, yeah, what about the elephant in the room? You know, the Emperor's new clothes, Samaria. So the, I actually open the book with the Emperor's new clothes because that's a story about common knowledge. Yes. When little boy said the Emperor was naked, he wasn't telling anyone they didn't, anything they didn't already know. But he was changing their knowledge because when he blurted it out in public, now everyone knew that everyone else knew that everyone else knew. We converted private knowledge to common knowledge. So first of all, that made a difference. That's the climax of the story. What did it change their relationship with the Emperor from deference to ridicule and scorn? So a relationship of the Emperor? To the Emperor. To the Emperor. To the Taylor. Well, but to the Emperor too. At least in the, in the, the, the, the Taylor, but the Taylor fooled him. Does Taylor's fault the Emperor's fault? Which is why I'm going to have him killed right away as if he was clinging to a boat. Oh my God. Did I have a disinified version of that story? I mean, the Taylor is the one who should be. Yes, but at that moment in public, it was the Emperor's fault of the, embarrassed, especially in the Danny K version of the story where, where it was met with ridicule and scorn, you know, lyrics to the song. Okay. And deference is a matter of common knowledge. You defer to someone because you know they'll stand their ground. Why did they stand their ground because they know that you'll defer to them? Why do you, and how do they know that? Well, because you know that they know that they'll stand their ground at infinitum. So and what about the mutuality of respect? I mean, that's the flip side of that. Sometimes there's a matter of deference because you truly respect the person. They understand that you truly respect them and they respect that, you know? Yeah. And the different flavors of the hierarchical relationship, it could be dominance, which basically means, you know, I could hurt you if I wanted to. There can be status. I could help you if I wanted to. There can be expertise. You're, there's, you all have a common interest in the decisions being made by someone who knows what they're talking about. Or even sometimes if everyone's going in, you know, the expression hurting cats, even if no one has a particular reason to be the, the decider, it's best for everyone if there is a decider. And that can give you a hierarchical interest. But we do use metaphors like saving face out there. And the elephant in the room is obviously something that everyone can see in the evening. Right. Right. And it makes sense. So the elephant in the room is the emperor's new clothes because no one is talking about it. That's right. That's right. Even though everyone knows that it's there. That's it. Which is why the saying always is, let's acknowledge the elephant in the room. In other words, like we all see it. Now let's talk about, yeah. Come to you so far, I get the feeling that there's kind of a logic to common knowledge and maybe even like a code. That might then culturally vary. Yes. So I think the phenomenon of common knowledge and things that generate it like blunt speech, like eye contact is universal. But then what are the relationships that are negotiated with common knowledge or ratified by common knowledge? That is what can friends share? What kind of a boss demand of an employee? How is sex treated? Is it can it be transactional or is it only intimate? All of these mixing and matching of resources, relationship models and contexts. That's what makes culture different from one another. But in each case, there is some kind of common knowledge that holds the relationship in place that sets out what you're allowed to exchange, what you're allowed to hoard, what you're allowed to demand. But that's what it means to be a competent member of a culture to master that. Each one of them, big a matter of common knowledge. So Steven, I try to know what is common knowledge so that I can access it as an educator. I can tap it into it. I can add to it because I don't have to train people to know things that represent common knowledge. Comedians, your joke does not work unless everybody knows what you're talking about. The more universal, the better. And by universal, I mean. I mean, Earthwide, I'm a, I'm some astrophysicist here. Correct yourself. Okay. The more commonly accepted, the better. The more earthwide. Right. The more, the more earthwide, the better. But really it's about experiential knowledge. If I, even if you've never been through what I am talking about, if I can put you there, then you will laugh with me. There are many people, many comedians that talk about marriage and people who are single, laugh because they have observed somebody else in a relationship that they understand with this comedian and talk to them. That broadens your access points to the person. For instance, when Steven was talking about the lost couple and the woman was going to a bookstore and the man was going to a camera shop, the first thing that popped into my head was, well, listen, if you know what's good for you, you better go to that damn bookstore because every husband knows that if I don't show up at the bookstore, I'm in trouble. Okay. And that's the first thing that popped into my head. This is an important point because what humor often does is it establishes common knowledge that is if you get the joke, then what has just been made public is something that you privately you along and so you get that feeling of solid area with the other person. If you're laughing at the same thing, then what was unstated that makes the joke funny is something that you have in common. That's why humor is such an important bonding agent for endating one of the main criteria in accepting a major sense of humor. Sense of humor. And since I'm not sure if it's thought deeply about that fact. It has to be more entertaining, but it's more bonding. What it means is that you share a lot of common ground, common knowledge that is you can't get the joke unless there is some hidden, unstated premise that makes it work. That can bond people. It can also be a devastating put down and an intolerable insult. I give the famous example of the roast at the National Press Correspondence Dinner during the Obama presidency where Donald Trump was in the audience and Obama made a number of jokes at Trump's expense. Ordinarily, people are expected to be a good sport and to accept the barbs showing that they have commonality, common ground with everyone in the room. That Trump took it personally who's visibly human and scowling at a joke like, well, be good if Donald Trump was present because he could accomplish things like closing Guantanamo because he has a history of running waterfront real estate into the ground. That's a great joke. Now, Trump didn't think so. It's a terrible joke. So the point is that everyone who laughed, first of all, knew that Trump despite his boasts of being a business genius had a string of failures which made it all the more painful for Trump for that to be brought out into the open. According to some stories, that's what led him to run to the first point. Yeah, for revenge. And they're all now being investigated by my justice department. There was a hoax, Obama, and his joke. So what happens when the humorists just twists the common knowledge? And I think you've got you touched this in the book, toilet paper shortage. Oh, yeah. And the origin of that story. So there's some viral fads and phenomena which can be really significant. So common knowledge is a kind of virulent property. It can be. Yes, exactly. So in the case of, say, a bank run where a rumor starts that the bank might be in trouble. Now of course, banks don't have enough cash on hand to redeem all their deposits. But if you worry that other people worry, that still other people worry, that other people worry that the bank might be insolvent, then everyone rushes to the bank to withdraw their savings, which can actually cause the bank to fail, even if it was a sound. And that can bring down an entire economy. That was in part the cause of the great depression. And so when Roosevelt said the only thing we have to fear is fear itself. This was a theorem of common knowledge. It wasn't just a feel good bromide, but he's accurately diagnosing the situation, which is why. That was a Roosevelt speaking to flat earthers. The only thing we have to fear is fear itself. Oh my God. I don't know if he'd been waiting for that. Oh my God. That's a good one. It's so bad. I'm laughing at that. Oh my God. It's totally good. He got you that joke out. I'm not. That was a dead joke. And of course, the run on the bank got me though I got to say. The run on the bank in Mary Poppins was caused by a little child. Yes. It took his coin, hit some kind of pants or something. In chilling chips. Yeah. To start an account, but the boy didn't want him to do that. They'd give me back my money. And then this permeated the walls of the man. Oh, I know. To all the ladies over here. They all over here. They're not giving him his money. I want my money. And then there's a run on the bank. That's so funny. That's great. So once again, something that is public can then set off cycles of thinking about what other people are thinking about what other people are thinking. That's the virulence you're talking about. Yeah. Just try it through. Yep. And a similar phenomenon might be why there was a toilet paper shortage during the COVID pandemic. It actually wasn't a toilet paper shortage until people thought there was this toilet paper shortage. Right. Horted because they thought other people were hoarding. When stores started posting maximum three rules per customer, that didn't so much throttle the demand. As it reassured everyone that there was a shortage. Well, that other people wouldn't be able to strip the shelves bare. So they didn't have to worry about stripping the shelves bare. I only need three rules. But I'm only going to ask for three rules because none of the other people can buy more than three rules either. Right. And so that kind of is level center. It's a level center. It's a level center. It's a level center. It's a level center. By the way, I still have toilet paper from the pentamacall. According to one story, it came from a big common knowledge generator in the day, namely Johnny Carson on the Tonight Show. So in the old era of three networks, Johnny Carson was the king of the world. He was the king of late night. He hosted the Tonight Show for many decades. When you were watching it, you had a good reason to think that the rest of the country was watching it and knew that the rest of the country was watching it in the early 70s after the oil embargo. When there wasn't oil shortage, he made the joke one night. You know, we have shortage of everything these days. There's shortage of gasoline. There's shortage of meat. There's shortage of coffee. But you hear the latest. I read it in the papers. There's a shortage of toilet paper. Now, it turns out there wasn't a shortage of toilet paper. There's a joke. As soon as you made the joke, there was a shortage of toilet paper. As everyone started to hoard toilet paper. So fulfilling. And according to at least one theory, ever since then, whenever there is a hurricane or a blizzard, people think that toilet paper is the thing you got to stock up on, because everyone else is going to have a shortage of curbian enthusiasm, where someone was revealed to have an entire closet full of toilet paper. Oh, yes, during the pandemic. That's right. That's a great, entire closet. But how much ass wiping do you think you need to do? How big is your head? By the way, in a hurricane, when you're home floods, that toilet paper is not going to be worth anything. What toilet paper really isn't so much fun, I'm saying. But in the other direction, you can also get speculative bubbles. You buy crypto because you think other people are buying crypto. At least we'll want to buy crypto tomorrow. So I'll pay for more for it tomorrow than you pay today. Right. They're buying it tomorrow, because I think they'll sell it to someone who wants to buy it the day after tomorrow. The hot pit. Yes. The greater fool. The greater fool. The greater fool. And that goes back to John Maynard Keynes, in the 1920s, compared speculative investing. So this is investing not because of the return that you expect on the asset. That is the profits that the manufacturer will make selling widgets or the farmer selling food. But you think you can unload the security at a profit on someone else. Right. They say it's like a beauty contest where instead of picking the prettiest face, the object is to pick the face that the most other people pick, where they're picking the face with the same goal that is trying to figure out what everyone else is picking. Wow. So it's always called a Keynesian beauty contest. Do we have that in primaries? The elections? And in elections are Keynesian beauty contest. That is, in a primary election where there may be a field of a dozen candidates. And no one wants to waste their vote in just deciding who's going to come in at seventh place as opposed to eight places. Which is what ranked for voting is trying to. That's why, yes, that's exactly what it's trying to resolve. And so people are hyper aware for any signs that someone has momentum that they're in the lead because they want to vote to determine who comes in first, not who comes in sixth. Right. I don't want to waste a vote. I don't want to waste a vote. And so during the coverage, any various trivial gaps and lapses or boosts can sometimes shoot candidates to the top or sink their candidates candidacy. Like when a few years ago, and Howard Dean was running for it. And everyone knew you can't vote for Dean now because his victory screen means that everyone knew that he had a silly victory screen. And that entered his agency. Can you imagine? Seriously? No, I'm, yes. Don't make fun of us. No, no, no, no. You're not a weird politician yourself. I know. I'm the only qualified candidate who was not able to continue his candidacy because he was like, and then we're going to go to New Hampshire. And then we're going to go to Vermont. And then we're going to go to, and he did that. And everybody was like, oh, dude, you can't be president, not acting like that. And then years later, we're just like, you know, you can grab him by, you can grab him by the whatever. You can just grab him anywhere you want. And they sometimes let you do it because of me. And we're like, yeah, that's the guy. That's the guy right there. We got to let that guy. All right. I'm loving all Trump. Interesting because what he did is done repeatedly is that he has flouted norms that everyone thought were inviolable. They were inviolable only because people thought they were inviolable. Exactly. They existed as common expectation, common knowledge. And as soon as he flouted them and did not pay the price, they no longer existed as norms, which is why they're I think being copied by people like Elon Musk, also a troll liar, a braggart. Yeah, that things that would be unthinkable for a president, for a CEO, as soon as they're thinkable, they're thinkable. So is this the fracturing of common knowledge that is partly behind the polarity of society right now where people are just refusing and disinterested mainly to find a common ground? Yeah. So common knowledge always is to find relative to a network of sharing of information. It could be two people. And some of the examples we've discussed, it could be the entire country. And there has been a segregation into two separate pools of common knowledge. Everyone blames social media and that probably has something to do with it. Yeah. But I think it's also cable news, Fox News, prior to social media had that effect. You weren't watching Walter Cronkite at the same time as everyone else was watching Walter Cronkite or Johnny Carson. And residential segregation. And you had educated people flocking to cities, leaving behind the less educated. You had a decline in organizations that brought people together across the socio-economic divides, like the army in the era of the draft, like churches, like service organizations, like the Lions Club, like bowling clubs. You stop rubbing shoulders with people from different social classes. Which one then hung out with people like them and then the common knowledge that they shared started to grow disjoint? Yeah. So it feeds divisiveness because I mean, it's the same issue as you said, multi-culturally. Right. Except now it's within the same culture, but now people dividing with the same motive, not the same culture. Because it's not different cultures within the same country. Within the same country. Yeah. That makes me feel like it's exacerbated by what I'll call the vi-tuportive disposition of leadership right now. Yeah. So I don't know what that word means. I'm sorry. What does that word mean? Like a vi-tuportive. Like a vi-tuportive. It means like a very SAT. Is it? How do I call it? It means like mean and nasty. Like a sniper. Okay. So when we're siloed into these different camps like this, it becomes very easy then to point fingers and say, that's your enemy, that's your enemy, that's your enemy. And then it's okay to be mean and nasty towards those people. And it seems like that's exactly where we are. Not to Germany. Yeah. That's right. I wasn't even thinking along those lines, but absolutely. Yes. That's how it went down. But the norms of civility, things you just don't say. You might disagree with someone. You might even not think highly of them, but you don't insult them to their face. I mean, you do in the playground, but there was a norm in politics, in corporations, in the media that you pretend that you like them even if you don't. And those are some of the norms that are better shattered. You don't lie blatantly. Now everyone lies somewhat. Just, all of us probably tell two lies a day. But you don't blatantly lie. You don't show a contempt for the truth. You at least try to pretend that you're honest. I give an example. So I befriended a, I have a sort of Republican confidant who's in Congress for like 25 years. You can tell them that it's me, Neil. He was in through Reagan and beyond. And then I, I was talking to Al Gore and I was saying I was friends with this guy. But I had to work it because we come from different places. And you know what he said? He didn't say anything bad. He just said, yeah, he's an acquired taste. That was, that was pretty politic. That is a very politic. Right. He didn't insult. He just said, you know, you got to, you got to work it. And then as any acquired taste would be. So that's an example. You don't hear that today. People just, like when Winston Churchill was asked, maybe the reason you lost the election to climate at least that people thought that, um, at least it was more modest. He said, well, Mr. Atley has much to be modest about. He did have a good term of phrase. Do you? Let me ask you before we have to wrap this up. Yeah, we got to start wrapping. What plays out if society remains unchecked where the common knowledge is distorted or the common knowledge is dictated by the loudest voice, no matter what that voice is saying. Yeah, but by nefarious forces. Yeah. Influencing. Yeah, well, we've seen some of it. We're seeing the polarization, particularly the negative polarization that is not just disagreeing by thinking that the other side is stupid or evil. I don't have an algorithm for reversing that, but the kind of norms that we should spread would be ones of civil disagreement, epistemic humility, charity, things that go against human nature where we tend to think of argument as a competition, as a war. I attacked his arguments. He defended them, but then I demolished them. We use the metaphors of war in talking about argument. Yeah. And in one of the chapters I talk about a different model for argument coming out of a mathematical theorem, claiming that we rational agents should not agree to disagree. That's how I feel both of the way. Well, there's actually some proof by the Israeli mathematician Robert Alman, that depends on common knowledge. We don't have time to go through it now, but it does set an alternative paradigm for argument that instead of two people beating each other up in the one left standing wins, that's not how you discover the truth, or even bargaining and negotiating and you come to some compromise. You think about why should the truth just happen to lie halfway in between two opinionated guys? But rather, it's kind of a random walk where when two people exchange information, they might go all over the map until they converge on a common conclusion. That's what that's precisely how I feel. I mean, otherwise you're just like you would as a scientist. Yes. That is kind of like your whole field. If we disagree, it's because there's insufficient data to create the agreements and not that. Let's go have a beer and invent the experiments that will resolve this. They have it. Yeah. That would be the kind of norm. It goes against human nature. I think the progress of science shows it's the best way to do things. And even, of course, scientists are not immune to pissing contest, dominant, dominant contest. And that's, at least we acknowledge it's a bad thing. That norm to spread in journalism, in politics, in the court system would be a good thing. It would be to transform it into more truth less, to the preparation. Once again, science saves the day. Science! And he said for the preparation, he doubled down on it. I see what he did there. I think we got to call it quits there. Oh my gosh. It's a great conversation, man. Let me see if I can take us out with a quick cosmic perspective with your permission. Okay. I'm feeling it, do it, look. Yeah. I remember studying the universe, which is a huge complex place. All the laws of physics I learned in physics class are applied in some place in some way at some time in the unfolding universe. Also the laws of chemistry and our search for life in the universe. There's the biology that we bring with us. All of this. And every time I reflect on that, I think to myself, this is not the hardest thing we can think about out there. You know what the hardest thing is? The human mind. What's going on inside there? And we've got psychologists, neuroscientists. It's a whole field trying to figure ourselves out. And I'm glad I do something as easy as astrophysics, relative to what they've got to worry about. And I just hope that the study of the human mind by the human mind is not the most complex thing we ever have to tackle in this universe. But if it is, get ready for that ride because the human mind is not logical, it's not rational, only occasionally. It was not only the source of everything we value and call civilization. It may actually be the end of it as well if we're not careful. That's a cosmic perspective. Stephen, thanks for joining us. Thank you so much. Great pleasure. Thank you. Stephen, please give me the title again. When everyone knows that everyone knows, dot, dot, dot. You got it. There you go. Jack, always a pleasure. All right, Gary. Pleasure, my friend. This has been Star Talk, special edition, Neil deGrasse Tyson. You're a personal astrophysicist. As always, look at me.