1 00:00:05,120 --> 00:00:08,760 Speaker 1: Why do people speak in innuendo when they're on a date. 2 00:00:09,440 --> 00:00:14,000 Speaker 1: Why do dictators try to squelch protests, Why do we 3 00:00:14,520 --> 00:00:17,520 Speaker 1: join up with bullies to gang up on an outcast. 4 00:00:18,079 --> 00:00:20,799 Speaker 1: Why do humans stand out from the rest of the 5 00:00:20,840 --> 00:00:25,720 Speaker 1: animal kingdom by blushing and laughing and crying? And what 6 00:00:25,760 --> 00:00:28,720 Speaker 1: does any of this have to do with George Costanza 7 00:00:29,200 --> 00:00:33,840 Speaker 1: or when Harry met Sally, or anonymity on social media 8 00:00:34,000 --> 00:00:39,080 Speaker 1: or cancel culture, or why we generally don't say everything 9 00:00:39,280 --> 00:00:45,920 Speaker 1: we mean. Welcome to Intercosmos with me David Eagleman. I'm 10 00:00:45,920 --> 00:00:49,480 Speaker 1: a neuroscientist and author at Stanford and in these episodes 11 00:00:49,520 --> 00:00:53,160 Speaker 1: we sail deeply into our three pound universe to understand 12 00:00:53,240 --> 00:00:55,959 Speaker 1: why and how our lives looks the way they do. 13 00:01:13,080 --> 00:01:17,479 Speaker 1: Today's episode is about a phenomenon known as common knowledge, 14 00:01:17,880 --> 00:01:21,039 Speaker 1: which is something that I know and you know, and 15 00:01:21,120 --> 00:01:24,280 Speaker 1: we both know that we know it. Now, this could 16 00:01:24,319 --> 00:01:26,920 Speaker 1: seem like a very particular sort of thing to pay 17 00:01:26,959 --> 00:01:31,039 Speaker 1: attention to, but many psychologists and economists over the past 18 00:01:31,120 --> 00:01:34,600 Speaker 1: decades have started to think that a deeper understanding of 19 00:01:35,200 --> 00:01:39,319 Speaker 1: common knowledge could explain all kinds of things about human 20 00:01:39,400 --> 00:01:43,280 Speaker 1: nature and behavior and societies, and for a very long time. 21 00:01:43,319 --> 00:01:46,280 Speaker 1: This has grabbed the attention of my friend and colleague 22 00:01:46,319 --> 00:01:49,040 Speaker 1: Stephen Pinker, who just this week has a new book 23 00:01:49,080 --> 00:01:53,800 Speaker 1: coming out on common knowledge called When Everyone Knows That 24 00:01:53,960 --> 00:01:56,920 Speaker 1: Everyone Knows, And so I called him up to discuss 25 00:01:57,000 --> 00:01:59,520 Speaker 1: this topic. I'll take just a moment to frame this 26 00:01:59,680 --> 00:02:02,320 Speaker 1: before I begin the interview. At the heart of the 27 00:02:02,440 --> 00:02:07,280 Speaker 1: issue is that we are a massively social species. We 28 00:02:07,400 --> 00:02:11,400 Speaker 1: form lifelong relationships, and we join clubs, and we're parts 29 00:02:11,440 --> 00:02:14,919 Speaker 1: of tribes, and we're citizens of countries. And we're also 30 00:02:15,080 --> 00:02:18,080 Speaker 1: a highly intelligent species, and we spend a lot of 31 00:02:18,080 --> 00:02:23,320 Speaker 1: our time, usually unconsciously, figuring out who knows what and 32 00:02:23,480 --> 00:02:26,840 Speaker 1: what we know in common, and for that matter, thinking 33 00:02:26,840 --> 00:02:30,840 Speaker 1: about how we can expand common knowledge with the right signals, 34 00:02:31,080 --> 00:02:36,080 Speaker 1: and often how we could hide things from becoming common knowledge. 35 00:02:36,639 --> 00:02:39,079 Speaker 1: The key thing to understand for today's conversation is that 36 00:02:39,440 --> 00:02:42,960 Speaker 1: common knowledge is not just about a bunch of individuals 37 00:02:42,960 --> 00:02:45,680 Speaker 1: each knowing something. It's that each person knows it and 38 00:02:45,800 --> 00:02:48,760 Speaker 1: knows that everyone else knows it, and knows that everyone 39 00:02:48,760 --> 00:02:51,200 Speaker 1: else knows that they know it, and so on. And 40 00:02:51,240 --> 00:02:55,160 Speaker 1: the argument is that it's this ladder of shared awareness 41 00:02:55,680 --> 00:03:00,920 Speaker 1: that allows societies to coordinate. Think about something like the 42 00:03:00,919 --> 00:03:04,560 Speaker 1: game of chicken, where two drivers speed towards each other. 43 00:03:04,960 --> 00:03:08,240 Speaker 1: Each knows the situation, but the critical factor is whether 44 00:03:08,639 --> 00:03:11,640 Speaker 1: both drivers know what the other is willing to do, 45 00:03:11,720 --> 00:03:14,720 Speaker 1: and whether both know that the other knows. And the 46 00:03:14,760 --> 00:03:18,040 Speaker 1: effects of common knowledge stretch from two people all the 47 00:03:18,080 --> 00:03:21,920 Speaker 1: way up to countries. For example, history is filled with 48 00:03:22,040 --> 00:03:27,079 Speaker 1: moments when private thoughts turned into common knowledge and changed 49 00:03:27,120 --> 00:03:30,160 Speaker 1: the world. So, for example, in nineteen eighty nine, East 50 00:03:30,200 --> 00:03:33,400 Speaker 1: Germans had long doubted the regime, but it was only 51 00:03:33,680 --> 00:03:37,360 Speaker 1: when tens of thousands gathered in the streets when everyone 52 00:03:37,400 --> 00:03:41,240 Speaker 1: could see that everyone else had the same doubts. That's 53 00:03:41,320 --> 00:03:45,120 Speaker 1: when the Berlin Wall fell. Stock Market bubbles and crashes 54 00:03:45,280 --> 00:03:48,480 Speaker 1: run on the same sort of principle. Investors don't care 55 00:03:48,840 --> 00:03:51,960 Speaker 1: only about the value of a stock, but about what 56 00:03:52,080 --> 00:03:56,800 Speaker 1: everyone else believes everyone else believes about its value. So 57 00:03:56,960 --> 00:03:59,720 Speaker 1: this is the type of thing that Pinker's book explores, 58 00:03:59,800 --> 00:04:04,160 Speaker 1: all all the ways in which common knowledge permeates everyday life. 59 00:04:06,040 --> 00:04:10,000 Speaker 1: Common knowledge, for example, is why etiquette works. You don't 60 00:04:10,040 --> 00:04:12,640 Speaker 1: just know the rules, you know that others know them too. 61 00:04:13,040 --> 00:04:17,200 Speaker 1: It's why red lights function not because you fear the police, 62 00:04:17,240 --> 00:04:19,840 Speaker 1: but because you know that everyone else knows the rule 63 00:04:20,120 --> 00:04:22,760 Speaker 1: and is going to stop. It's why children learn to 64 00:04:22,760 --> 00:04:25,800 Speaker 1: play Peek a boo, because the delight comes from that 65 00:04:26,000 --> 00:04:29,080 Speaker 1: shared loop of I know that, you know that I'm here. 66 00:04:29,640 --> 00:04:33,400 Speaker 1: So today we'll explore the phenomenon of common knowledge. Stephen 67 00:04:33,400 --> 00:04:36,800 Speaker 1: Pinker is a cognitive scientist and linguist at Harvard and 68 00:04:36,839 --> 00:04:41,040 Speaker 1: he's a longtime bestselling author who is famous for illuminating 69 00:04:41,080 --> 00:04:44,560 Speaker 1: the hidden structures of human thought and society. His new 70 00:04:44,600 --> 00:04:48,560 Speaker 1: book dives into the puzzle of common knowledge, how it arises, 71 00:04:48,640 --> 00:04:52,240 Speaker 1: why it matters, and what it reveals about the architecture 72 00:04:52,560 --> 00:05:00,719 Speaker 1: of our social minds. Stephen joins me, Now, so, Steve, 73 00:05:00,800 --> 00:05:04,520 Speaker 1: we are an intensely social species and there's a lot 74 00:05:04,600 --> 00:05:07,000 Speaker 1: that has to happen in order to get us to 75 00:05:07,040 --> 00:05:09,120 Speaker 1: coordinate as a result. And this is the thing you've 76 00:05:09,160 --> 00:05:13,200 Speaker 1: been thinking about, So tell us how do we coordinate 77 00:05:13,240 --> 00:05:13,960 Speaker 1: as a species. 78 00:05:14,640 --> 00:05:20,200 Speaker 2: Well, any two agents who need to coordinate need common knowledge. 79 00:05:20,320 --> 00:05:23,520 Speaker 2: The theme of the book, common knowledge, being the state 80 00:05:23,520 --> 00:05:26,200 Speaker 2: where I know something, you know it, I know that 81 00:05:26,240 --> 00:05:27,880 Speaker 2: you know it, you know that I know it, I 82 00:05:27,960 --> 00:05:29,920 Speaker 2: know that you know that I know that you know it, 83 00:05:30,000 --> 00:05:34,200 Speaker 2: ad infinitum. Why Because it isn't enough for each party 84 00:05:34,240 --> 00:05:35,680 Speaker 2: to know what the other one is going to do, 85 00:05:36,160 --> 00:05:38,680 Speaker 2: because the other party guessing what the first one is 86 00:05:38,720 --> 00:05:40,880 Speaker 2: going to do may do something complete different. So just 87 00:05:41,040 --> 00:05:46,280 Speaker 2: be concrete. If we're going to rendezvous and we don't 88 00:05:46,320 --> 00:05:49,200 Speaker 2: generate common knowledge by a conversationalist, and my cell phone 89 00:05:49,240 --> 00:05:51,320 Speaker 2: goes dead, so each of us asked to guess where 90 00:05:51,360 --> 00:05:53,560 Speaker 2: the other one is going to go. It's not enough 91 00:05:53,600 --> 00:05:55,520 Speaker 2: for me to know that you like to go to Starbucks, 92 00:05:55,880 --> 00:05:58,200 Speaker 2: because you may know that I like to go to Pete's. 93 00:05:58,320 --> 00:06:00,320 Speaker 2: And so if I go to Starbucks, that's where you're 94 00:06:00,320 --> 00:06:01,920 Speaker 2: going to go. You might go to pizza because you 95 00:06:01,920 --> 00:06:04,200 Speaker 2: think that's where I'm going to go. And well, I 96 00:06:04,240 --> 00:06:06,480 Speaker 2: know that, okay, so I'll go to Pietz because Dave 97 00:06:06,520 --> 00:06:07,680 Speaker 2: knows that I like to go to pizza. But wait 98 00:06:07,720 --> 00:06:09,520 Speaker 2: a sec Dave knows that I know they likes to 99 00:06:09,520 --> 00:06:11,400 Speaker 2: go to Starbucks, so he's going to go to Starbucks 100 00:06:11,440 --> 00:06:15,640 Speaker 2: after all, and so on. Nothing short of actually blurting 101 00:06:15,640 --> 00:06:18,800 Speaker 2: it out in each other's presence will get you on 102 00:06:18,880 --> 00:06:24,320 Speaker 2: the same page. Some kind of public perceptible self evidence signal. 103 00:06:24,440 --> 00:06:27,200 Speaker 2: That's what is needed for coordination. 104 00:06:27,800 --> 00:06:30,479 Speaker 1: You've, of course spent much of your career studying language, 105 00:06:30,920 --> 00:06:36,200 Speaker 1: and so you see language as one way of establishing 106 00:06:36,240 --> 00:06:39,159 Speaker 1: that common knowledge give us a sense of that, Yeah, 107 00:06:39,240 --> 00:06:39,840 Speaker 1: you know that. 108 00:06:39,839 --> 00:06:42,920 Speaker 2: I'm trying to get you to believe something because you 109 00:06:43,000 --> 00:06:45,800 Speaker 2: know that I'm saying something with the intent that you 110 00:06:45,839 --> 00:06:48,080 Speaker 2: believe it. That's kind of what language is. So it's 111 00:06:48,120 --> 00:06:53,120 Speaker 2: a common knowledge generator when it is something is blurted out. 112 00:06:53,880 --> 00:06:56,479 Speaker 2: What got me interested in this whole topic is actually 113 00:06:56,480 --> 00:07:00,280 Speaker 2: almost the converse cases in which we try to avoid 114 00:07:00,600 --> 00:07:04,480 Speaker 2: common knowledge when we don't say something in so many words, 115 00:07:05,240 --> 00:07:08,680 Speaker 2: but we put our meaning between the lines. We count 116 00:07:08,680 --> 00:07:11,040 Speaker 2: on our reader to connect the dots. We use euphemism 117 00:07:11,160 --> 00:07:14,320 Speaker 2: or innuendo or hinting or beating around the bush or 118 00:07:14,360 --> 00:07:17,080 Speaker 2: hilly shallowing, which is a lot of language. That's one 119 00:07:17,080 --> 00:07:19,480 Speaker 2: of the reasons it took so long to get computers 120 00:07:19,480 --> 00:07:22,600 Speaker 2: to understand language. If you simply parse who did what 121 00:07:22,680 --> 00:07:24,600 Speaker 2: to whom based on the subject of the verb and 122 00:07:24,640 --> 00:07:27,200 Speaker 2: the object, you're really not going to understand what people 123 00:07:27,360 --> 00:07:30,720 Speaker 2: actually meant, such as if you could pass a salt, 124 00:07:30,720 --> 00:07:34,600 Speaker 2: that would be awesome. Okay, now think about that. I mean, 125 00:07:34,640 --> 00:07:37,160 Speaker 2: that doesn't make it much sense. It would literally be awesome, 126 00:07:37,480 --> 00:07:41,640 Speaker 2: And you know, it's not like you're just pondering possible worlds. 127 00:07:41,680 --> 00:07:43,760 Speaker 2: That's not the meaning. Everyone knows what the meaning is. 128 00:07:43,800 --> 00:07:46,760 Speaker 2: It's give me the salt, and a lot of languages 129 00:07:46,840 --> 00:07:48,800 Speaker 2: like that, and linguists have long known it. But the 130 00:07:48,880 --> 00:07:52,120 Speaker 2: question is why what do we try to accomplish when 131 00:07:52,200 --> 00:07:55,800 Speaker 2: we avoid blurting something what we want out? In so 132 00:07:55,840 --> 00:07:58,800 Speaker 2: many words, what I suggest is that the we're avoiding 133 00:07:58,840 --> 00:08:02,080 Speaker 2: common knowledge. That is, each one knows what the other 134 00:08:02,120 --> 00:08:04,280 Speaker 2: one is doing, but you may not know that the 135 00:08:04,320 --> 00:08:06,240 Speaker 2: other one knows that you know that they know, and 136 00:08:06,280 --> 00:08:10,360 Speaker 2: that allows you to preserve a certain relationship, relationships being 137 00:08:10,800 --> 00:08:14,800 Speaker 2: coordination problems, as we mentioned at the top of the conversation, 138 00:08:15,240 --> 00:08:19,840 Speaker 2: a relationship like being friends, being lovers, being a supervisor 139 00:08:19,840 --> 00:08:23,560 Speaker 2: in supervisory, being transaction partners. Those are all matters of 140 00:08:23,600 --> 00:08:26,920 Speaker 2: common knowledge. We're friends not because we signed a contract, 141 00:08:26,960 --> 00:08:28,880 Speaker 2: but because each one knows that the other one knows 142 00:08:28,920 --> 00:08:32,240 Speaker 2: that there we're friends, and that can be threatened by 143 00:08:32,600 --> 00:08:36,120 Speaker 2: certain things that could become a common knowledge that contradict 144 00:08:36,160 --> 00:08:40,400 Speaker 2: the basis of the friendship, like a sexual proposition. So 145 00:08:40,559 --> 00:08:43,040 Speaker 2: why do people say things like I want to come 146 00:08:43,120 --> 00:08:45,560 Speaker 2: up for Netflix and show, or you want to come 147 00:08:45,600 --> 00:08:48,760 Speaker 2: up for coffee when you know, though you know, let's 148 00:08:48,760 --> 00:08:50,440 Speaker 2: say it's a man saying it to a woman. You know, 149 00:08:50,600 --> 00:08:52,800 Speaker 2: she wasn't born yesterday. She's a grown up, she knows 150 00:08:52,840 --> 00:08:56,360 Speaker 2: what it means. But it's still way better than Hey, 151 00:08:56,400 --> 00:08:58,680 Speaker 2: you want to come up and have sex, which would 152 00:08:59,040 --> 00:09:02,960 Speaker 2: be you know, both parties. You are pretty uncomfortable, even 153 00:09:02,960 --> 00:09:05,280 Speaker 2: though would you like to come up for coffee? Doesn't 154 00:09:05,280 --> 00:09:07,480 Speaker 2: make them uncomfortable? How come that was the problem that 155 00:09:07,520 --> 00:09:09,880 Speaker 2: I took up in a previous book, The Stuff of Thought. 156 00:09:10,120 --> 00:09:12,679 Speaker 2: Language is a Window into human nature, which had a 157 00:09:12,800 --> 00:09:16,000 Speaker 2: chapter called games People play on language as a window 158 00:09:16,040 --> 00:09:19,920 Speaker 2: into social relationships and in trying to figure out why 159 00:09:19,960 --> 00:09:24,119 Speaker 2: we don't just blurt out what we mean. Other examples 160 00:09:24,160 --> 00:09:27,240 Speaker 2: being say a failed bribe. Let's see you trying to 161 00:09:27,440 --> 00:09:30,040 Speaker 2: jump the queue in a restaurant and you slip the 162 00:09:30,160 --> 00:09:32,960 Speaker 2: major DA twenty dollars bill and say, I just wondering 163 00:09:32,960 --> 00:09:36,560 Speaker 2: if you might have a cancelation, or this is an 164 00:09:36,559 --> 00:09:38,400 Speaker 2: important night from you. Is there any way to shorten 165 00:09:38,440 --> 00:09:41,719 Speaker 2: my weight? Why don't people just say if I give 166 00:09:41,760 --> 00:09:45,559 Speaker 2: you twenty dollars, will you see me? Right? Away or fundraising. 167 00:09:45,600 --> 00:09:48,079 Speaker 2: I've seen this a lot at Harvard. I'm sure you've 168 00:09:48,080 --> 00:09:50,720 Speaker 2: seen a similar thing where the dean will say to 169 00:09:50,760 --> 00:09:53,520 Speaker 2: the rich people in the audience, we're counting on you 170 00:09:53,600 --> 00:09:57,600 Speaker 2: to show leadership, to be a friend to the university 171 00:09:58,000 --> 00:10:00,520 Speaker 2: instead of the reason we're all here is you're going 172 00:10:00,520 --> 00:10:03,120 Speaker 2: to open your checkbook and write, you know, a check 173 00:10:03,160 --> 00:10:06,680 Speaker 2: for five million dollars. That's another case where people don't 174 00:10:06,720 --> 00:10:10,120 Speaker 2: say what they mean. Why not? And here's the answer 175 00:10:10,160 --> 00:10:13,200 Speaker 2: that got me interested in common knowledge. And I've done 176 00:10:13,200 --> 00:10:16,839 Speaker 2: studies to back this up that if it's do you 177 00:10:16,920 --> 00:10:19,440 Speaker 2: want to come up for coffee? Well, you know, she 178 00:10:19,559 --> 00:10:22,160 Speaker 2: knows what he means, and you know obviously he knows 179 00:10:22,160 --> 00:10:25,400 Speaker 2: what he means. But does she know that he knows 180 00:10:25,480 --> 00:10:29,560 Speaker 2: that she knows? With an innuendo like would you like 181 00:10:29,600 --> 00:10:32,160 Speaker 2: to come up for coffee, she could think, well, maybe 182 00:10:32,160 --> 00:10:34,720 Speaker 2: he thinks I'm naive, and if I said no, maybe 183 00:10:34,720 --> 00:10:37,600 Speaker 2: he thinks, you know, caffeine would keep me up. Even 184 00:10:37,600 --> 00:10:39,760 Speaker 2: though she knows that she's turned down a sexual overture, 185 00:10:39,800 --> 00:10:41,840 Speaker 2: he knows it as well, but he could not know 186 00:10:41,840 --> 00:10:43,800 Speaker 2: why because she knows that he knows. And likewise he 187 00:10:43,840 --> 00:10:46,400 Speaker 2: could think, well, you know, maybe she thinks I'm dead, 188 00:10:46,720 --> 00:10:49,679 Speaker 2: Maybe she thinks that I think that she's just turned 189 00:10:49,679 --> 00:10:55,280 Speaker 2: down coffee. Uh. They can maintain their platonic friendship with 190 00:10:55,400 --> 00:11:00,959 Speaker 2: the common knowledge that it's just about companionship. Whereas he 191 00:11:01,040 --> 00:11:02,560 Speaker 2: said you want to come up for half sex and 192 00:11:02,640 --> 00:11:06,320 Speaker 2: she said no, they can never be platonic friends in 193 00:11:06,360 --> 00:11:09,400 Speaker 2: the same way. Again, the intuition is it's out there, 194 00:11:09,600 --> 00:11:13,560 Speaker 2: you can't take it back, And I suggest that technically 195 00:11:13,640 --> 00:11:17,800 Speaker 2: what's happening is that the blurted out speech generates common knowledge. 196 00:11:18,040 --> 00:11:22,240 Speaker 2: Common knowledge is the basis of our relationships. Their coordination, games, 197 00:11:22,840 --> 00:11:28,200 Speaker 2: euphemism and innuendo get a message across without generating common knowledge, 198 00:11:28,200 --> 00:11:30,240 Speaker 2: and that's why we fall back on it so often. 199 00:11:30,559 --> 00:11:34,559 Speaker 1: Okay, so that's how we sometimes try to mask common knowledge. 200 00:11:35,480 --> 00:11:39,040 Speaker 1: Tell us about how common knowledge is useful in society, 201 00:11:39,200 --> 00:11:43,959 Speaker 1: society wide, let's say, with public demonstrations and politics and economics. 202 00:11:44,320 --> 00:11:47,640 Speaker 2: Yeah, a lot of our large scale coordination, not just 203 00:11:48,000 --> 00:11:52,160 Speaker 2: two friends or Roande going for coffee or agreeing to 204 00:11:52,200 --> 00:11:57,000 Speaker 2: be platonic friends, but large scale things like everyone recognizing money, 205 00:11:57,559 --> 00:12:01,520 Speaker 2: Like why do I accept a green piece of paper 206 00:12:01,520 --> 00:12:04,120 Speaker 2: in exchange for something of value? Well, because I know 207 00:12:04,200 --> 00:12:07,040 Speaker 2: that other people will accept it and give me something 208 00:12:07,040 --> 00:12:08,840 Speaker 2: of value. Why would they do that, Well, they know 209 00:12:08,920 --> 00:12:11,800 Speaker 2: that still other people would accept it. So the value 210 00:12:11,800 --> 00:12:17,120 Speaker 2: of currency depends on common knowledge. Everyone knows it's worth something, 211 00:12:17,160 --> 00:12:18,880 Speaker 2: and that's what makes it worth something. The fact that 212 00:12:18,920 --> 00:12:22,200 Speaker 2: everyone knows that everyone knows it. A lot of power 213 00:12:22,440 --> 00:12:26,160 Speaker 2: depends on common knowledge. There are laws, there's courts, there's 214 00:12:26,160 --> 00:12:28,200 Speaker 2: a police force, there's a jail. But most of the 215 00:12:28,200 --> 00:12:31,240 Speaker 2: time people just follow the law, even though big brothers 216 00:12:31,480 --> 00:12:36,559 Speaker 2: watching them twenty four to seven. However, these things can change. 217 00:12:37,760 --> 00:12:40,520 Speaker 2: It's not easy to change them when the basis of 218 00:12:40,720 --> 00:12:44,520 Speaker 2: power or money is just common knowledge, because everyone has 219 00:12:44,559 --> 00:12:48,600 Speaker 2: an interest in keeping up the common assumption. But sometimes 220 00:12:48,640 --> 00:12:52,360 Speaker 2: it can unravel. In the case of power, if there 221 00:12:52,440 --> 00:12:56,600 Speaker 2: is a public protest, everyone shows up at a public 222 00:12:56,640 --> 00:12:59,680 Speaker 2: square at the same time, the same place, everyone sees 223 00:12:59,720 --> 00:13:04,720 Speaker 2: everyone else there. Previously, maybe that everyone was resentful of 224 00:13:04,760 --> 00:13:08,559 Speaker 2: the system, thought it was inefficient and oppressive. They may 225 00:13:08,600 --> 00:13:11,400 Speaker 2: even have suspected that everyone else had the same feeling, 226 00:13:11,440 --> 00:13:13,640 Speaker 2: but they didn't know that other people knew that. They 227 00:13:13,760 --> 00:13:17,760 Speaker 2: knew they couldn't coordinate by all rising at the same time, 228 00:13:18,200 --> 00:13:20,920 Speaker 2: and so the regime could keep them in their place 229 00:13:21,320 --> 00:13:25,160 Speaker 2: by preventing common knowledge. And that's why dictators don't allow 230 00:13:25,240 --> 00:13:28,240 Speaker 2: freedom of assembly, freedom of the press, freedom of speech, 231 00:13:28,640 --> 00:13:34,320 Speaker 2: precisely because they're afraid that people coordinating which they could 232 00:13:34,320 --> 00:13:40,240 Speaker 2: only do with common knowledge, could acting together overpower a regime. Likewise, 233 00:13:40,280 --> 00:13:43,360 Speaker 2: in the case of going back to money again, if 234 00:13:43,400 --> 00:13:47,240 Speaker 2: the value of money depends on common knowledge, then when 235 00:13:47,240 --> 00:13:50,559 Speaker 2: the common knowledge is threatened, the value of money can disappear. 236 00:13:50,559 --> 00:13:52,960 Speaker 2: And that's what happens when you get hyperinflation, people taking 237 00:13:52,960 --> 00:13:55,280 Speaker 2: home their wages in a wheelbarrow because no one will 238 00:13:55,640 --> 00:14:00,480 Speaker 2: accept it anymore, or a bank run where people withdraw 239 00:14:00,520 --> 00:14:03,640 Speaker 2: their savings, not necessarily because they think that there's anything 240 00:14:03,640 --> 00:14:06,079 Speaker 2: wrong with a bank, but as long as there's a 241 00:14:06,200 --> 00:14:08,560 Speaker 2: rumor that other people think that there's a problem with 242 00:14:08,600 --> 00:14:11,080 Speaker 2: the bank, and they're withdrawing their money out of fear 243 00:14:11,120 --> 00:14:13,480 Speaker 2: that still other people will withdraw their money, it suddenly 244 00:14:13,480 --> 00:14:17,040 Speaker 2: becomes rational to withdraw your money while the bank still 245 00:14:17,080 --> 00:14:19,400 Speaker 2: has money to withdraw. And that can cause a bank 246 00:14:19,440 --> 00:14:21,640 Speaker 2: to fail, that can cause the whole economy to fail. 247 00:14:21,640 --> 00:14:24,400 Speaker 2: That's what happened in nineteen twenty nine. And so when 248 00:14:24,520 --> 00:14:27,360 Speaker 2: Roosevelt said the only thing we have to fear is 249 00:14:27,400 --> 00:14:31,880 Speaker 2: fear itself. He was stating a theorem of common knowledge 250 00:14:31,920 --> 00:14:34,560 Speaker 2: that was quite literally true, that what people had to 251 00:14:34,600 --> 00:14:37,000 Speaker 2: fear was fear itself, and the fear of fear, the 252 00:14:37,040 --> 00:14:41,240 Speaker 2: recursive fear, the common knowledge, could actually change the value 253 00:14:41,280 --> 00:14:44,000 Speaker 2: of those financial institutions. 254 00:14:45,440 --> 00:14:47,480 Speaker 1: So here's something I wanted to dig in with you 255 00:14:47,560 --> 00:14:50,080 Speaker 1: about after reading your book. How do we think about 256 00:14:50,480 --> 00:14:54,040 Speaker 1: false common knowledge? By which I mean, let's imagine that 257 00:14:54,080 --> 00:14:56,320 Speaker 1: you and I engage in a public protest and we 258 00:14:56,320 --> 00:14:58,200 Speaker 1: look around and we see a thousand people around us. 259 00:14:58,200 --> 00:15:01,240 Speaker 1: We say, look, everybody clear feels this way, but we're 260 00:15:01,240 --> 00:15:04,280 Speaker 1: not aware of that across town there's a larger protest 261 00:15:04,320 --> 00:15:07,160 Speaker 1: with ten thousand people in it, and we have the 262 00:15:07,160 --> 00:15:10,520 Speaker 1: impression that everyone feels the same way we do about something. 263 00:15:10,840 --> 00:15:14,000 Speaker 2: I mean that technically be common belief rather than common knowledge, 264 00:15:14,040 --> 00:15:17,720 Speaker 2: But different pools of people can have different common beliefs, 265 00:15:18,080 --> 00:15:22,200 Speaker 2: and there can also be common misconceptions where prior to 266 00:15:22,280 --> 00:15:27,400 Speaker 2: the protest, there are cases where people think that everyone 267 00:15:27,400 --> 00:15:30,280 Speaker 2: else believes something. In fact, everyone could believe that everyone 268 00:15:30,280 --> 00:15:33,240 Speaker 2: else believes someone something and no one actually believes it, 269 00:15:33,360 --> 00:15:37,360 Speaker 2: sometimes called a pluralistic ignorance. Or a spiral of silence. 270 00:15:37,560 --> 00:15:38,680 Speaker 1: What's an example of that. 271 00:15:39,280 --> 00:15:43,359 Speaker 2: A classic case study of pluralistic ignorance in social psychology 272 00:15:43,640 --> 00:15:47,840 Speaker 2: was when some psychologists interviewed the guys in the fraternity. 273 00:15:48,400 --> 00:15:50,160 Speaker 2: They found that every one of them thought that it 274 00:15:50,200 --> 00:15:52,800 Speaker 2: was really stupid to drink so much that you pass out, 275 00:15:53,240 --> 00:15:57,080 Speaker 2: but everyone thought that all the other frat bros thought 276 00:15:57,120 --> 00:15:59,480 Speaker 2: it was cool. No one actually thought it was cool, 277 00:15:59,480 --> 00:16:03,000 Speaker 2: but that all the others thought it was cool. And 278 00:16:03,160 --> 00:16:05,440 Speaker 2: there are probably a lot of cases like that. I mean, 279 00:16:05,720 --> 00:16:08,640 Speaker 2: an extreme case would be The Emperor's New Clothes, where 280 00:16:08,720 --> 00:16:12,280 Speaker 2: everyone thought that everyone else thought that who were seeing clothes, 281 00:16:12,360 --> 00:16:14,720 Speaker 2: no one actually saw clothes, And it took the little 282 00:16:14,720 --> 00:16:19,640 Speaker 2: boy blurting it out generating common knowledge, for the common 283 00:16:19,640 --> 00:16:25,640 Speaker 2: misconception to flip into common knowledge. The Emperor's New Clothes 284 00:16:25,720 --> 00:16:28,800 Speaker 2: is a story about common knowledge. The boy wasn't telling 285 00:16:29,000 --> 00:16:32,600 Speaker 2: anyone anything they didn't already know, but it was changing 286 00:16:32,640 --> 00:16:35,800 Speaker 2: the state of their knowledge because now everyone knew that 287 00:16:35,840 --> 00:16:39,280 Speaker 2: everyone else knew, and that changed their relationship with the 288 00:16:39,360 --> 00:16:43,680 Speaker 2: Emperor from a deference to scorn and ridicule. 289 00:16:59,600 --> 00:17:02,440 Speaker 1: I do worry a little bit, though, about people assuming 290 00:17:02,640 --> 00:17:07,640 Speaker 1: politically common knowledge and saying, Hey, if I just make 291 00:17:07,680 --> 00:17:11,040 Speaker 1: some innuendo, everyone will understand what I mean by this, 292 00:17:11,280 --> 00:17:14,320 Speaker 1: because that often doesn't work, especially now. 293 00:17:14,760 --> 00:17:16,760 Speaker 2: Well, the thing about innuendo is that it has to 294 00:17:16,800 --> 00:17:24,520 Speaker 2: be calibrated so that it is recognized by a kind 295 00:17:24,520 --> 00:17:29,119 Speaker 2: of willing recipient, but can be denied by an unwilling recipient. 296 00:17:29,160 --> 00:17:32,439 Speaker 2: So it has to be calibrated in that zone, and 297 00:17:32,480 --> 00:17:35,719 Speaker 2: there can be errors in either direction. Where there's an 298 00:17:35,760 --> 00:17:40,919 Speaker 2: episode of Seinfeld where George Costanza is invited up for 299 00:17:40,960 --> 00:17:43,359 Speaker 2: coffee and says no because he's got to get to 300 00:17:43,359 --> 00:17:45,960 Speaker 2: work early the next morning, and then as he's walking out, 301 00:17:46,280 --> 00:17:48,600 Speaker 2: he says, oh, my god, coffee doesn't mean coffee. Coffee 302 00:17:48,680 --> 00:17:52,800 Speaker 2: in sex. So there's the Costanza problem that it could 303 00:17:52,920 --> 00:17:56,399 Speaker 2: be so subtle that it goes over the head, or 304 00:17:56,440 --> 00:18:00,080 Speaker 2: there could be conversely, it's so blatant that the the 305 00:18:00,600 --> 00:18:04,560 Speaker 2: unwilling hearer calls you on it again. You know, all 306 00:18:04,560 --> 00:18:07,560 Speaker 2: of these things, by the way, are worked out in fiction, 307 00:18:07,840 --> 00:18:12,720 Speaker 2: in comedies, comedies of manners, situation comedies. They kind of 308 00:18:12,880 --> 00:18:19,199 Speaker 2: allow us to exercise our facility for recursive mentalizing, that is, 309 00:18:19,280 --> 00:18:21,680 Speaker 2: getting inside the head of other people, getting inside the 310 00:18:21,840 --> 00:18:24,040 Speaker 2: head of other people and so they're often worked out 311 00:18:24,280 --> 00:18:28,360 Speaker 2: that so often were drives fictional plots. But the opposite 312 00:18:28,400 --> 00:18:32,800 Speaker 2: is when when Harry met Sally, and Harry, you know, 313 00:18:32,880 --> 00:18:36,399 Speaker 2: early on, is kind of complimenting Sally and they just 314 00:18:36,480 --> 00:18:39,480 Speaker 2: met kind of a little too insistently, and then she 315 00:18:39,640 --> 00:18:42,520 Speaker 2: blows the listle. She says, you're coming on to me, 316 00:18:42,920 --> 00:18:46,640 Speaker 2: which leads to a wonderful discussion of common knowledge. I mean, 317 00:18:46,680 --> 00:18:50,200 Speaker 2: not not in those words where he says, okay, let's 318 00:18:50,240 --> 00:18:51,680 Speaker 2: say I was coming on to you. What are we 319 00:18:51,720 --> 00:18:53,760 Speaker 2: going to do? I take it back? Okay, I take 320 00:18:53,760 --> 00:18:56,600 Speaker 2: it back, and she says, you can't take it back. 321 00:18:57,080 --> 00:18:58,600 Speaker 2: He says, what do you mean you can't take it back? 322 00:18:58,640 --> 00:18:59,680 Speaker 2: You know, what are we going to do? Call the 323 00:18:59,720 --> 00:19:03,480 Speaker 2: cop and she says, it's out there. It's too late, 324 00:19:04,200 --> 00:19:08,600 Speaker 2: So it's out there. That is a metaphor for common knowledge. 325 00:19:08,840 --> 00:19:11,600 Speaker 2: That is something that's out there, is something that you 326 00:19:11,680 --> 00:19:15,360 Speaker 2: see other people see, you see them see it. And 327 00:19:15,840 --> 00:19:18,679 Speaker 2: direct speech or even in this case, indirect speech that 328 00:19:18,880 --> 00:19:22,359 Speaker 2: was not indirect enough. It kind of exceeded that. The 329 00:19:22,400 --> 00:19:26,159 Speaker 2: cutoff is out there, and when it's out there, it 330 00:19:26,280 --> 00:19:29,359 Speaker 2: changes the nature of the relationship. They were no longer 331 00:19:29,520 --> 00:19:33,680 Speaker 2: just near strangers, platonic friends. He had turned it into 332 00:19:34,000 --> 00:19:36,560 Speaker 2: a sexual relationship, which you rebuffed. 333 00:19:37,080 --> 00:19:39,359 Speaker 1: Great, So I want to return for just a second 334 00:19:39,440 --> 00:19:43,440 Speaker 1: to literature, which you mentioned fictions, because I made the 335 00:19:43,520 --> 00:19:46,399 Speaker 1: argument on this podcast little while ago that I'm not 336 00:19:46,760 --> 00:19:50,800 Speaker 1: so worried about AI completely taking the job of writers. 337 00:19:51,600 --> 00:19:53,600 Speaker 1: And I listened five different reasons, but one of them 338 00:19:53,640 --> 00:19:57,760 Speaker 1: had to do with the fact that we could all 339 00:19:57,880 --> 00:20:01,600 Speaker 1: generate totally bespoke literature, just like Kings of Yesteryear would do. 340 00:20:03,040 --> 00:20:04,960 Speaker 1: But we lose something there, which is that a big 341 00:20:05,000 --> 00:20:07,760 Speaker 1: part of literature is the social glue, the fact that 342 00:20:07,800 --> 00:20:10,040 Speaker 1: everyone else has read the same story. I don't want 343 00:20:10,080 --> 00:20:13,119 Speaker 1: my Game of Thrones to have a different outcome than 344 00:20:13,160 --> 00:20:16,840 Speaker 1: your Game of Thrones. So my question to you is, 345 00:20:17,160 --> 00:20:19,960 Speaker 1: what is the reason we desire common knowledge so much? 346 00:20:20,560 --> 00:20:22,760 Speaker 2: I think it's a great example, and people may not 347 00:20:22,840 --> 00:20:27,520 Speaker 2: remember that back in the nineties, when the internet first 348 00:20:27,560 --> 00:20:30,520 Speaker 2: became a thing, there was the idea that you could 349 00:20:31,480 --> 00:20:33,840 Speaker 2: dial in whatever ending to a story you wanted. That 350 00:20:33,960 --> 00:20:36,880 Speaker 2: fiction would be, movies would be the same. Everyone could 351 00:20:36,880 --> 00:20:39,439 Speaker 2: watch that movie. Maybe let's they didn't take off. And 352 00:20:39,520 --> 00:20:43,360 Speaker 2: I think it's the reason that you identified, namely part 353 00:20:43,359 --> 00:20:47,880 Speaker 2: of the experience of art is that it's common knowledge. 354 00:20:48,400 --> 00:20:51,080 Speaker 2: You know about something at the same time you know 355 00:20:51,119 --> 00:20:54,399 Speaker 2: that everyone else knows about it, and that's what gives 356 00:20:54,400 --> 00:20:59,280 Speaker 2: you something in common that can reinforce a social relationship. 357 00:20:59,320 --> 00:21:01,679 Speaker 2: With friendship, a movie with friends, you talk about it 358 00:21:01,720 --> 00:21:05,200 Speaker 2: with friends, and the common experience is one of those 359 00:21:05,240 --> 00:21:10,199 Speaker 2: things that kind of go makes friends friends. They go 360 00:21:10,280 --> 00:21:14,560 Speaker 2: through things together, they share common interests. The basis, the 361 00:21:14,920 --> 00:21:19,080 Speaker 2: common knowledge, that's the tacit basis of friendship is that 362 00:21:19,119 --> 00:21:21,240 Speaker 2: we're kind of there's a kind of a mind mild, 363 00:21:22,200 --> 00:21:25,760 Speaker 2: even a you know, a body meld, where that we 364 00:21:25,800 --> 00:21:29,240 Speaker 2: are in physical proximity, We hug, we shake hands, all 365 00:21:29,280 --> 00:21:31,440 Speaker 2: the more intense and romantic relationship. 366 00:21:31,720 --> 00:21:33,720 Speaker 1: Okay, So I want to return and dig in just 367 00:21:33,760 --> 00:21:36,359 Speaker 1: a little on this point because I'm fascinated by this 368 00:21:36,560 --> 00:21:40,639 Speaker 1: about false common knowledge what I'm calling that or a 369 00:21:40,680 --> 00:21:46,760 Speaker 1: misconception about it. So, for example, recently, Charlie Kirk was 370 00:21:46,800 --> 00:21:50,399 Speaker 1: assassinated in broad daylight, and if you look on X 371 00:21:50,440 --> 00:21:53,320 Speaker 1: and if you look on blue Sky, you find very 372 00:21:53,359 --> 00:21:58,200 Speaker 1: different stories about that. And presumably the people who are 373 00:21:58,240 --> 00:22:02,400 Speaker 1: tweeting or blue skying are thinking, hey, this is great. 374 00:22:02,440 --> 00:22:04,760 Speaker 1: We have shared common knowledge. But you in fact have 375 00:22:04,800 --> 00:22:08,520 Speaker 1: two groups of people. I'm exaggerating a little bit the difference, 376 00:22:08,560 --> 00:22:12,560 Speaker 1: but you have different groups that have beliefs that they 377 00:22:12,600 --> 00:22:17,359 Speaker 1: believe are shared by everybody. Just one second example. This 378 00:22:17,560 --> 00:22:21,879 Speaker 1: My grandmother I remember many years ago in Florida said 379 00:22:22,520 --> 00:22:25,080 Speaker 1: I can't believe that so and so just one governor, 380 00:22:25,520 --> 00:22:28,679 Speaker 1: because I don't know anybody that voted for him. And 381 00:22:28,720 --> 00:22:31,000 Speaker 1: it was true, of course she didn't know anybody, but 382 00:22:31,040 --> 00:22:32,960 Speaker 1: it doesn't mean that the majority of the state didn't 383 00:22:33,000 --> 00:22:33,479 Speaker 1: vote for him. 384 00:22:33,480 --> 00:22:37,040 Speaker 2: Nonetheless, Yeah, I mean common knowledge, or more accurately, in 385 00:22:37,080 --> 00:22:39,359 Speaker 2: a lot of these cases, is common belief, That is, 386 00:22:39,359 --> 00:22:41,679 Speaker 2: you believe something, you believe that other people believe that 387 00:22:41,680 --> 00:22:45,560 Speaker 2: you believe it, and so on. Is relative to a network, 388 00:22:45,760 --> 00:22:48,720 Speaker 2: a community which can be disconnected from another network, and 389 00:22:48,760 --> 00:22:51,280 Speaker 2: the common knowledge is often generated since none of us 390 00:22:51,400 --> 00:22:56,320 Speaker 2: experience everything firsthand. In fact, on for politics, we experience 391 00:22:56,359 --> 00:22:58,760 Speaker 2: almost nothing firsthand, and we read about it, we hear 392 00:22:58,800 --> 00:23:03,560 Speaker 2: about it. If the sources are disjoint, then the pools 393 00:23:03,560 --> 00:23:06,600 Speaker 2: of common knowledge within each of these networks could be disjoined. 394 00:23:06,960 --> 00:23:11,520 Speaker 2: And that happens partly from social media, as even feeds 395 00:23:11,560 --> 00:23:14,359 Speaker 2: within a platform, but even more so when they're different 396 00:23:14,359 --> 00:23:17,880 Speaker 2: platforms like X versus Blue Sky, or in the case 397 00:23:17,920 --> 00:23:22,040 Speaker 2: of cable news, do you watch Fox News or do 398 00:23:22,040 --> 00:23:24,960 Speaker 2: you watch CNN or do you watch MSNBC. So one 399 00:23:24,960 --> 00:23:26,800 Speaker 2: of the users I take up in the book, and 400 00:23:26,840 --> 00:23:30,800 Speaker 2: this intersects with my interest in academic freedom and freedom 401 00:23:30,840 --> 00:23:33,880 Speaker 2: of speech in another part of my life where I 402 00:23:34,000 --> 00:23:36,679 Speaker 2: co founded and I'm the co president of the Council 403 00:23:36,720 --> 00:23:40,119 Speaker 2: and Academic Freedom at Harvard. Why is free speech so 404 00:23:40,160 --> 00:23:44,440 Speaker 2: important and all the more so in a country? Why 405 00:23:44,560 --> 00:23:47,480 Speaker 2: is freedom of speech enshrined in the First Amendment to 406 00:23:47,480 --> 00:23:50,760 Speaker 2: the American Constitution, Freedom of the press, freedom of assembly. 407 00:23:51,040 --> 00:23:53,560 Speaker 2: So what is it about speech that can be so 408 00:23:53,680 --> 00:23:59,440 Speaker 2: threatening to a dictator? You might think, Well, the dictator 409 00:23:59,480 --> 00:24:01,479 Speaker 2: would be tend to let people bitch and moan all 410 00:24:01,520 --> 00:24:07,000 Speaker 2: they want. He's what with the guns, And as Mao said, 411 00:24:07,119 --> 00:24:08,919 Speaker 2: power comes out of the barrel of a gun. So 412 00:24:09,200 --> 00:24:16,720 Speaker 2: why should a public protest or a critical editorial be 413 00:24:16,880 --> 00:24:20,760 Speaker 2: so threatening to a dictator? Well, the reason is, as 414 00:24:21,160 --> 00:24:26,800 Speaker 2: Gandhi said in the eponymous movie, he says to a 415 00:24:26,840 --> 00:24:29,960 Speaker 2: British officer in the end, you will leave because there's 416 00:24:29,960 --> 00:24:33,320 Speaker 2: simply no way that one hundred thousand Englishmen can control 417 00:24:33,400 --> 00:24:36,320 Speaker 2: three hundred and fifteen million Indians if the Indians refuse 418 00:24:36,400 --> 00:24:39,200 Speaker 2: to cooperate. So that's just a truth about numbers then, 419 00:24:39,560 --> 00:24:41,439 Speaker 2: But it raises the question, how do you get three 420 00:24:41,520 --> 00:24:46,159 Speaker 2: hundred and fifteen million people cooperating or in this case coordinating. Well, 421 00:24:46,359 --> 00:24:52,639 Speaker 2: some public event demonstration where you're protesting, you can see 422 00:24:52,840 --> 00:24:55,919 Speaker 2: everyone else protesting, and everyone can see everyone else. You know, 423 00:24:56,080 --> 00:25:02,040 Speaker 2: the time is now a prominent public uh declaration you know, 424 00:25:02,200 --> 00:25:06,959 Speaker 2: Jacques or an article. Everyone knows now that it's public 425 00:25:07,080 --> 00:25:10,760 Speaker 2: that everyone hates the regime and people can, you know, 426 00:25:10,840 --> 00:25:15,199 Speaker 2: either storm the palace or just refuse to work or 427 00:25:15,240 --> 00:25:18,440 Speaker 2: to cooperate. And so dictators don't want that to happen. 428 00:25:18,720 --> 00:25:21,720 Speaker 2: They want to prevent the generation of common knowledge, which 429 00:25:21,760 --> 00:25:26,919 Speaker 2: is why police states control both public assembly and public media. 430 00:25:27,240 --> 00:25:29,320 Speaker 2: I give a joke. I recount a joke from the 431 00:25:29,320 --> 00:25:32,280 Speaker 2: era of the Soviet Union in which a man is 432 00:25:32,280 --> 00:25:35,600 Speaker 2: handing out leaflets in Red Square and of course they're 433 00:25:35,760 --> 00:25:38,640 Speaker 2: sure enough the KGB arrested. They take them back to headquarters, 434 00:25:39,040 --> 00:25:41,960 Speaker 2: only to discover that these leaflets are blank sheets of paper, 435 00:25:42,480 --> 00:25:44,919 Speaker 2: and they think, what is the meaning of this? And 436 00:25:44,960 --> 00:25:48,280 Speaker 2: he says, what's there to say, it's so obvious. So 437 00:25:48,440 --> 00:25:51,480 Speaker 2: that's a joke about common knowledge. Namely, he was being 438 00:25:51,520 --> 00:25:55,160 Speaker 2: subversive because by the very act just handing out leaflets 439 00:25:55,240 --> 00:25:58,720 Speaker 2: didn't matter what they said. That now everyone who accepted 440 00:25:58,720 --> 00:26:01,639 Speaker 2: the leaflets accepting seeing everyone else except the belief that 441 00:26:01,800 --> 00:26:04,320 Speaker 2: they all knew that there was something to protest, and 442 00:26:04,400 --> 00:26:06,960 Speaker 2: they didn't have to be told what it was because 443 00:26:07,119 --> 00:26:11,080 Speaker 2: they knew privately what it was. The act of communication 444 00:26:11,400 --> 00:26:14,600 Speaker 2: was that giving it out in a public square made 445 00:26:14,640 --> 00:26:17,959 Speaker 2: the private knowledge common, and that was threatening to the regime, 446 00:26:18,119 --> 00:26:21,960 Speaker 2: which is why, in a case of life imitating a joke, 447 00:26:22,400 --> 00:26:26,120 Speaker 2: Putin's regime has arrested people for carrying blank science. 448 00:26:28,080 --> 00:26:30,359 Speaker 1: I'm sorry to return to this point, but if you 449 00:26:30,440 --> 00:26:32,919 Speaker 1: stood on a street corner and said I'm protesting, and 450 00:26:32,960 --> 00:26:38,359 Speaker 1: you handed out blank sheets of paper, the lefties would 451 00:26:38,400 --> 00:26:40,560 Speaker 1: think one thing from the blank sheet, and the right's 452 00:26:40,600 --> 00:26:44,520 Speaker 1: would think another thing. And so in an ideal sitution, 453 00:26:44,560 --> 00:26:47,040 Speaker 1: I mean, we look at the Soviet regime as a failure, 454 00:26:47,080 --> 00:26:48,919 Speaker 1: and so we say, okay, it was obvious what he 455 00:26:49,080 --> 00:26:52,080 Speaker 1: meant by that. But I'm interested in the fact that 456 00:26:52,119 --> 00:26:55,800 Speaker 1: we each have very different internal models. Let's say, with 457 00:26:55,840 --> 00:27:02,000 Speaker 1: politics and so the transmission of common knowledge isn't so 458 00:27:02,160 --> 00:27:03,119 Speaker 1: easy in a sense. 459 00:27:03,880 --> 00:27:07,360 Speaker 2: Well, yes, I mean it depends on a conspicuous public 460 00:27:07,440 --> 00:27:11,600 Speaker 2: signal and in general from a trusted source and who 461 00:27:11,680 --> 00:27:16,919 Speaker 2: trusts who can vary between interconnected but disjoint networks of people. 462 00:27:18,480 --> 00:27:19,840 Speaker 2: But it's not, you know, it's not the case that 463 00:27:19,920 --> 00:27:24,160 Speaker 2: everyone goes that own way. Otherwise we wouldn't have society, 464 00:27:24,200 --> 00:27:27,600 Speaker 2: we wouldn't have science, we wouldn't have markets, we wouldn't 465 00:27:27,600 --> 00:27:28,320 Speaker 2: have currency. 466 00:27:28,560 --> 00:27:31,200 Speaker 1: But we do have parties. We do have two different 467 00:27:31,200 --> 00:27:34,440 Speaker 1: parties that increasingly disagree more and more we do. 468 00:27:34,560 --> 00:27:36,480 Speaker 2: Yes, I mean that, As I said, there can be 469 00:27:37,160 --> 00:27:43,600 Speaker 2: the common belief within semi disconnected networks, within each of 470 00:27:43,640 --> 00:27:48,040 Speaker 2: which you have common belief, but not necessarily in the 471 00:27:47,800 --> 00:27:52,560 Speaker 2: the entire group. The general phenomena are that common knowledge 472 00:27:52,600 --> 00:27:57,960 Speaker 2: is generated by public signals that people see when they 473 00:27:58,119 --> 00:28:01,840 Speaker 2: know that everyone else sees sees themselves seeing it. And 474 00:28:01,880 --> 00:28:07,000 Speaker 2: again that can be relative to pop the population and 475 00:28:07,040 --> 00:28:12,040 Speaker 2: the connected network that sees each other seeing something at 476 00:28:12,040 --> 00:28:12,680 Speaker 2: the same time. 477 00:28:12,840 --> 00:28:16,040 Speaker 1: So tell us about cancel culture and also why cancel 478 00:28:16,080 --> 00:28:18,879 Speaker 1: culture is more possible in a world where people can 479 00:28:18,920 --> 00:28:19,920 Speaker 1: hide behind keyboards. 480 00:28:20,040 --> 00:28:22,879 Speaker 2: Yes, I have a chapter in the book called the 481 00:28:22,880 --> 00:28:26,560 Speaker 2: Canceling Instinct, and it does touch on my interest in 482 00:28:26,600 --> 00:28:29,199 Speaker 2: academic freedom, but the point of the chapter isn't so 483 00:28:29,280 --> 00:28:31,359 Speaker 2: much to make the case for academic freedom, though I 484 00:28:31,400 --> 00:28:36,600 Speaker 2: do reprise that, but as a psychologist, to ask, why 485 00:28:36,640 --> 00:28:40,440 Speaker 2: is there an urge to censor, to cancel, to punish 486 00:28:40,480 --> 00:28:43,800 Speaker 2: people for their opinions. Now, of course that's been true 487 00:28:43,960 --> 00:28:47,440 Speaker 2: for all of human history, or heretics have been burned 488 00:28:47,440 --> 00:28:52,120 Speaker 2: at the stake or crucified. But you think that in 489 00:28:52,520 --> 00:28:57,240 Speaker 2: universities of all places, for the arena where we ought 490 00:28:57,240 --> 00:29:01,680 Speaker 2: to be, not treat beliefs as sinful. May be mistaken, 491 00:29:01,920 --> 00:29:05,600 Speaker 2: maybe illogical, but then you point it out, why do 492 00:29:05,640 --> 00:29:08,560 Speaker 2: you try to destroy the person who's ventured that opinion. 493 00:29:08,800 --> 00:29:11,840 Speaker 2: That's the phenomenon of cancel culture, and I suggest it's 494 00:29:11,840 --> 00:29:18,240 Speaker 2: because a combination of two psychological phenomena. One of them 495 00:29:18,360 --> 00:29:22,959 Speaker 2: is that even though the whole basis of science and 496 00:29:23,040 --> 00:29:28,280 Speaker 2: scholarship is there is a truth, we have means to 497 00:29:28,320 --> 00:29:31,360 Speaker 2: try to approach it. We may be mistaken, but we're 498 00:29:31,400 --> 00:29:35,360 Speaker 2: not bad people because we're mistaken. That you believe things 499 00:29:35,400 --> 00:29:38,000 Speaker 2: to the extent that there's good evidence for, good arguments 500 00:29:38,000 --> 00:29:42,640 Speaker 2: for it, that whole complex of beliefs is kind of 501 00:29:42,800 --> 00:29:49,560 Speaker 2: weird in human history. And the more common attitude is 502 00:29:49,760 --> 00:29:53,520 Speaker 2: for most people most of the time, is your beliefs 503 00:29:53,520 --> 00:29:56,800 Speaker 2: are a reflection of who you are, whether in particular 504 00:29:56,880 --> 00:29:59,640 Speaker 2: what tribe you belong to, and whether you're a good person, 505 00:29:59,680 --> 00:30:04,240 Speaker 2: who usually means upholding the sacred beliefs of your tribe. 506 00:30:04,360 --> 00:30:07,720 Speaker 2: Now that is poison for science and for scholarship and 507 00:30:07,760 --> 00:30:10,360 Speaker 2: for academia. But it is the way that people think 508 00:30:11,120 --> 00:30:15,800 Speaker 2: that the beliefs I mean putting aside beliefs about here 509 00:30:15,840 --> 00:30:19,120 Speaker 2: and now, I mean there are you know, people don't hallucinate. 510 00:30:19,200 --> 00:30:21,600 Speaker 2: They know, you know there's food in the fridge. There 511 00:30:21,600 --> 00:30:24,200 Speaker 2: isn't food in the fridge. But when it comes to 512 00:30:24,640 --> 00:30:29,960 Speaker 2: more bigger questions, where did humans come from? Why is 513 00:30:30,000 --> 00:30:34,400 Speaker 2: their disease? Why are their revolutions? Why is their wealth 514 00:30:34,440 --> 00:30:38,560 Speaker 2: and inequality? Things that we academics tend to think can 515 00:30:38,600 --> 00:30:42,680 Speaker 2: be answered by the methods of science and scholarship. But 516 00:30:43,360 --> 00:30:48,640 Speaker 2: most people is what you believe signals what tribe, what 517 00:30:48,720 --> 00:30:51,360 Speaker 2: coalition you belong to, And you're bad if you have 518 00:30:51,400 --> 00:30:54,680 Speaker 2: the wrong belief So if you have that kind of 519 00:30:54,720 --> 00:30:59,120 Speaker 2: built in flaw in human belief, then there can be 520 00:30:59,360 --> 00:31:01,800 Speaker 2: norms as to what you believe in what you don't believe. 521 00:31:01,920 --> 00:31:05,600 Speaker 2: And norms are matters of common knowledge. They exist because 522 00:31:05,640 --> 00:31:09,360 Speaker 2: people believe they exist. They can be threatened if people 523 00:31:09,520 --> 00:31:29,480 Speaker 2: flout them and get away with it. So and we 524 00:31:29,560 --> 00:31:32,800 Speaker 2: have everyday social norms. You don't go around naked, you 525 00:31:32,840 --> 00:31:37,840 Speaker 2: don't make you pass gas in public, you don't tell 526 00:31:37,880 --> 00:31:41,960 Speaker 2: ethnic jokes anymore, you don't insult people's appearance to their face. 527 00:31:42,680 --> 00:31:45,600 Speaker 2: All these norms are held up just because it isn't done, 528 00:31:45,840 --> 00:31:48,720 Speaker 2: and everyone knows that it isn't done. Conversely, if it 529 00:31:48,800 --> 00:31:52,960 Speaker 2: is done, the norm can unravel. So people often feel 530 00:31:53,000 --> 00:31:58,520 Speaker 2: the need to prop up norms by if noting when 531 00:31:58,520 --> 00:32:03,480 Speaker 2: they're flouted in public and then punishing the violator in public. 532 00:32:03,560 --> 00:32:06,320 Speaker 2: And the punishment has to be public for it to 533 00:32:06,360 --> 00:32:09,720 Speaker 2: prop up the norm, which is why we used to 534 00:32:09,760 --> 00:32:15,400 Speaker 2: have public hangings and pillories and stocks and crucifixions. Only 535 00:32:15,400 --> 00:32:18,840 Speaker 2: if you have everyone seeing that the person is punished, 536 00:32:18,840 --> 00:32:21,360 Speaker 2: could the norm survive well. I think we now have 537 00:32:21,400 --> 00:32:26,840 Speaker 2: an equivalent, often an electronic equivalent, in social media, where 538 00:32:26,920 --> 00:32:30,360 Speaker 2: if someone does flow a norm, that is, they express 539 00:32:30,440 --> 00:32:33,720 Speaker 2: an opinion that goes against what you take to be 540 00:32:33,800 --> 00:32:37,680 Speaker 2: the moral convictions of your tribe. People feel the urge 541 00:32:37,720 --> 00:32:40,320 Speaker 2: to punish it in public, and that's really easy to 542 00:32:40,360 --> 00:32:41,400 Speaker 2: do on social. 543 00:32:41,080 --> 00:32:45,920 Speaker 1: Media and the anonymity of being behind the keyboard. I think, 544 00:32:46,000 --> 00:32:49,680 Speaker 1: you know, it's just like the trolley dilemma, where if 545 00:32:49,720 --> 00:32:52,440 Speaker 1: you have to push the person with your hands, it's different. 546 00:32:52,480 --> 00:32:55,040 Speaker 1: You activate these motional networks and you're less likely to 547 00:32:55,080 --> 00:32:57,720 Speaker 1: do that. But if you have to pull the lever 548 00:32:58,280 --> 00:33:01,000 Speaker 1: so that only one person gets killed instead of five people, 549 00:33:01,280 --> 00:33:03,360 Speaker 1: then most people are perfectly willing to do that at 550 00:33:03,360 --> 00:33:05,120 Speaker 1: a distance. And it strikes me it's the same thing 551 00:33:05,160 --> 00:33:06,720 Speaker 1: with the anonymity. 552 00:33:07,240 --> 00:33:10,240 Speaker 2: Well, that's right. And it also and this does relate 553 00:33:10,320 --> 00:33:14,920 Speaker 2: to another common knowledge phenomenon, that is that our social relationships. 554 00:33:16,000 --> 00:33:21,080 Speaker 2: Are we friends? Are we lovers? Are we boss and subordinate? 555 00:33:21,280 --> 00:33:28,240 Speaker 2: Are we neighbors, members of a civil society? A lot 556 00:33:28,240 --> 00:33:39,280 Speaker 2: of these are reinforced by common knowledge generators. Eye contact, handshakes, laughter, blushing, 557 00:33:39,960 --> 00:33:43,200 Speaker 2: eye contact, things that can't be denied. That is, you 558 00:33:43,240 --> 00:33:45,920 Speaker 2: look someone in the eye, you're looking at the part 559 00:33:45,920 --> 00:33:47,400 Speaker 2: of them that's looking at the part of you that's 560 00:33:47,400 --> 00:33:48,760 Speaker 2: looking at the part of them that's looking at the 561 00:33:48,760 --> 00:33:52,240 Speaker 2: part of you, ad infinitum. So it's an eye contact 562 00:33:52,320 --> 00:33:55,320 Speaker 2: is a common knowledge generator, and the common knowledge that 563 00:33:55,400 --> 00:33:59,160 Speaker 2: these signals generate tend to be things like, well, we're 564 00:33:59,160 --> 00:34:05,720 Speaker 2: all acting like we're members of a community. So indeed, 565 00:34:06,200 --> 00:34:09,080 Speaker 2: when those signals are present because you're face to face, 566 00:34:09,600 --> 00:34:13,000 Speaker 2: then that can restore the norms of how you deal 567 00:34:13,400 --> 00:34:16,040 Speaker 2: with a person in a peer group, namely, you don't 568 00:34:16,040 --> 00:34:19,680 Speaker 2: insult them to your face. Without those common knowledge generators, 569 00:34:19,719 --> 00:34:22,480 Speaker 2: such as in the anonymity of a keyboard, then you 570 00:34:22,520 --> 00:34:26,799 Speaker 2: can insult people, you can denigrate them, you can try 571 00:34:26,800 --> 00:34:29,000 Speaker 2: to destroy the reputations in a way that would be 572 00:34:29,120 --> 00:34:31,640 Speaker 2: kind of unthinkable in a face to face situation. 573 00:34:31,960 --> 00:34:34,160 Speaker 1: There's one piece I want to return to about cancel culture, 574 00:34:34,160 --> 00:34:37,759 Speaker 1: which is why everybody jumps on the bandwagon. You had 575 00:34:37,760 --> 00:34:41,680 Speaker 1: a section in your book about moral condemnation and why 576 00:34:42,200 --> 00:34:45,160 Speaker 1: it's better to join the bullies than to take the 577 00:34:45,280 --> 00:34:46,440 Speaker 1: risk of being bullied. 578 00:34:46,680 --> 00:34:49,919 Speaker 2: Yeah, yeah, give us a sense exactly. I mean, it's 579 00:34:49,920 --> 00:34:53,239 Speaker 2: a kind of a playground dynamic that many of us 580 00:34:53,400 --> 00:34:56,719 Speaker 2: remember sometimes with shame, when we may have joined the 581 00:34:58,320 --> 00:35:01,960 Speaker 2: bullying mob and out of fear of becoming the kid 582 00:35:01,960 --> 00:35:05,200 Speaker 2: that everyone picks on and there is there's an equivalent 583 00:35:05,239 --> 00:35:07,840 Speaker 2: in academias. I had to say where I mean, it 584 00:35:07,560 --> 00:35:10,160 Speaker 2: has no place because we're all in it together trying 585 00:35:10,160 --> 00:35:13,320 Speaker 2: to find the truth. But you get the instant petition 586 00:35:13,480 --> 00:35:16,040 Speaker 2: with six hundred signatures, which can usually gin up on 587 00:35:16,120 --> 00:35:18,800 Speaker 2: social media. There are enough grad students in the country 588 00:35:18,840 --> 00:35:21,360 Speaker 2: that you can get get this is to sign some 589 00:35:22,360 --> 00:35:26,440 Speaker 2: condemnatory petition. But I think it is some of the 590 00:35:26,440 --> 00:35:30,040 Speaker 2: same dynamic, and there is a dynamics. Sorry to keep 591 00:35:30,080 --> 00:35:32,879 Speaker 2: relating things to common knowledge, because it is the theme 592 00:35:32,880 --> 00:35:34,640 Speaker 2: of the book, the theme of our conversation, but I 593 00:35:34,680 --> 00:35:38,600 Speaker 2: do think that it governs many human interactions. There's a 594 00:35:38,640 --> 00:35:41,360 Speaker 2: theory from a former post doc online Peter to Sholey 595 00:35:41,600 --> 00:35:47,319 Speaker 2: and his former advisor Rob Kurzband that we know no 596 00:35:47,320 --> 00:35:49,719 Speaker 2: one is an island. We really want to be part 597 00:35:49,760 --> 00:35:54,840 Speaker 2: of some group, some posse, some band of brothers, because 598 00:35:54,880 --> 00:35:57,480 Speaker 2: you know we're sitting ducks. If we're isolated, how do 599 00:35:57,560 --> 00:35:59,719 Speaker 2: you know which group to join? You don't want to 600 00:35:59,719 --> 00:36:03,400 Speaker 2: be on the losing side. If you can find some 601 00:36:04,239 --> 00:36:08,759 Speaker 2: sin that someone has committed and you all jointly recognize 602 00:36:08,800 --> 00:36:13,120 Speaker 2: that they are a sinner, they've broken some norm some law, 603 00:36:13,560 --> 00:36:16,200 Speaker 2: you gang up on them. That's a and it's common 604 00:36:16,239 --> 00:36:18,880 Speaker 2: knowledge as you know that the other people recognize that 605 00:36:19,000 --> 00:36:22,720 Speaker 2: same violation. It is a basis for forming a coalition, 606 00:36:23,680 --> 00:36:28,279 Speaker 2: and people often will band together and to single out 607 00:36:28,320 --> 00:36:31,880 Speaker 2: some victim as and there's something that feels right about 608 00:36:31,960 --> 00:36:34,879 Speaker 2: being in that band, and it is the basis that 609 00:36:34,880 --> 00:36:38,719 Speaker 2: the coalitions could form and the target suffers their kind 610 00:36:38,760 --> 00:36:43,960 Speaker 2: of collateral damage. Probably the episode from fiction that kind 611 00:36:43,960 --> 00:36:45,760 Speaker 2: of draws that out of the most is the famous 612 00:36:45,760 --> 00:36:48,640 Speaker 2: story by Shirley Jackson called The Lottery, came out in 613 00:36:48,640 --> 00:36:52,520 Speaker 2: the late forties, often assigned in high school and debated 614 00:36:52,560 --> 00:36:56,920 Speaker 2: ever since, where the town folk of a Bucolic village 615 00:36:56,960 --> 00:37:00,560 Speaker 2: every year choose someone by lottery and stone to death 616 00:37:02,000 --> 00:37:05,400 Speaker 2: as a person, suggesting that there is some kind of 617 00:37:05,480 --> 00:37:09,080 Speaker 2: human urge to simply gang up on a victim and 618 00:37:09,960 --> 00:37:13,040 Speaker 2: they in this case. What makes the story so chilling 619 00:37:13,080 --> 00:37:16,240 Speaker 2: and so kind of absurd is the victim didn't actually 620 00:37:16,239 --> 00:37:18,920 Speaker 2: do something other than being the loser in the lottery. 621 00:37:19,080 --> 00:37:21,480 Speaker 2: But what it kind of played out, what continues to 622 00:37:21,480 --> 00:37:25,279 Speaker 2: make it fascinating is this dynamic of being part of 623 00:37:25,320 --> 00:37:29,840 Speaker 2: a mob united in its victimization of a victim. 624 00:37:30,040 --> 00:37:32,560 Speaker 1: Yeah, so it doesn't only have to do with the violation, 625 00:37:32,719 --> 00:37:39,560 Speaker 1: It has to do with the social bonding that results. Okay, great, 626 00:37:39,960 --> 00:37:44,520 Speaker 1: what else should everybody know about common knowledge? 627 00:37:44,760 --> 00:37:48,400 Speaker 2: Yes? Well, one of my favorite chapters, the one that 628 00:37:48,400 --> 00:37:50,319 Speaker 2: I had one of the most fun writing, was the 629 00:37:50,320 --> 00:37:55,400 Speaker 2: one on body language social signals laughing, crying, blushing, staring, 630 00:37:55,520 --> 00:38:00,879 Speaker 2: glaring on signals that I think we fall because they 631 00:38:00,920 --> 00:38:03,839 Speaker 2: were common knowledge generators. So in case, you know, why 632 00:38:03,840 --> 00:38:07,719 Speaker 2: do we blush? The mark twains and men is the 633 00:38:07,760 --> 00:38:13,560 Speaker 2: only animal that blushes or needs to and he was 634 00:38:13,640 --> 00:38:16,480 Speaker 2: he is right that men are. You know, humanity is 635 00:38:16,480 --> 00:38:19,719 Speaker 2: the only animal that plushes. There are other things that 636 00:38:19,880 --> 00:38:26,000 Speaker 2: also that make humans unique. We're the only species that 637 00:38:26,000 --> 00:38:30,279 Speaker 2: that weeps. We're the only species that laughs. There's a 638 00:38:30,440 --> 00:38:33,920 Speaker 2: kind of precursor in chimpanzees in a kind of panting 639 00:38:33,960 --> 00:38:36,759 Speaker 2: that a companies play fighting. But you know, it's not 640 00:38:37,719 --> 00:38:40,319 Speaker 2: like are exactly the same as our laughter. We are. 641 00:38:40,560 --> 00:38:44,280 Speaker 2: Eye contact is really important to humans, and that's probably 642 00:38:44,320 --> 00:38:47,440 Speaker 2: why we evolved a white sclera, the whites of our 643 00:38:47,480 --> 00:38:51,720 Speaker 2: eyes that other primates don't have. Why we have elongated 644 00:38:51,880 --> 00:38:56,680 Speaker 2: eyes so that our position of our eyes can easily 645 00:38:56,760 --> 00:39:01,200 Speaker 2: be discerned. So all of these I suggest are effective 646 00:39:01,320 --> 00:39:07,040 Speaker 2: because they when you express them, the perceiver knows that 647 00:39:07,120 --> 00:39:09,080 Speaker 2: you know that you're expressing them. So in the case 648 00:39:09,120 --> 00:39:13,759 Speaker 2: of blushing, you feel the heat of your cheeks from 649 00:39:13,800 --> 00:39:15,880 Speaker 2: the inside at the same time that you know that 650 00:39:15,920 --> 00:39:18,520 Speaker 2: other people can see them redden from the outside and 651 00:39:18,560 --> 00:39:21,480 Speaker 2: they know that you're feeling it. Because what makes blushing 652 00:39:21,520 --> 00:39:24,440 Speaker 2: so painful is knowing that other people know that you're blushing, 653 00:39:24,719 --> 00:39:29,120 Speaker 2: as when people say you're blushing, which makes people blush 654 00:39:29,160 --> 00:39:31,640 Speaker 2: all the more and can even make them blush if 655 00:39:31,640 --> 00:39:37,440 Speaker 2: they're not blushing, you know, or or tearing up weeping. 656 00:39:37,960 --> 00:39:41,520 Speaker 2: You're seeing the world through the kind of the scrim 657 00:39:41,560 --> 00:39:43,799 Speaker 2: of your own tears, and other people can see the 658 00:39:44,239 --> 00:39:47,400 Speaker 2: glisten or the trickle of your tears. So these are 659 00:39:47,440 --> 00:39:50,719 Speaker 2: cases where I think you're establishing something about your relationship 660 00:39:50,719 --> 00:39:56,240 Speaker 2: with the person in a involuntary, unfakable, and undeniable way. 661 00:39:56,600 --> 00:39:59,399 Speaker 2: In the case of blushing, it's I know that I've 662 00:39:59,440 --> 00:40:03,239 Speaker 2: screwed up by the norms that you hold, and so 663 00:40:03,400 --> 00:40:06,160 Speaker 2: even though I've screwed up, better that I know that 664 00:40:06,200 --> 00:40:09,040 Speaker 2: I've screwed up than that I just blow off your 665 00:40:09,080 --> 00:40:11,760 Speaker 2: norms as if I was some kind of loose cannon 666 00:40:11,920 --> 00:40:17,520 Speaker 2: or weirdo or psychopath. In the case of crying, it's 667 00:40:18,000 --> 00:40:22,640 Speaker 2: I acknowledge, defeat, surrender, helplessness. I'm not going to fight back. 668 00:40:22,800 --> 00:40:26,600 Speaker 2: It's going to be bodily equivalent of raising a white 669 00:40:26,640 --> 00:40:30,440 Speaker 2: flag or throwing in the towel in a boxing match. Anyway, 670 00:40:30,560 --> 00:40:33,520 Speaker 2: I talk about each one of these displays and why 671 00:40:33,600 --> 00:40:37,480 Speaker 2: I think they evolved as a common knowledge generator in 672 00:40:37,600 --> 00:40:41,239 Speaker 2: order to ratify a certain kind of social relationship. 673 00:40:41,880 --> 00:40:46,080 Speaker 1: Excellent, Yeah, I love that chapter. Okay, any closing thoughts 674 00:40:46,120 --> 00:40:47,520 Speaker 1: about common knowledge? 675 00:40:47,760 --> 00:40:50,000 Speaker 2: Yeah, just is. I think it's a missing piece of 676 00:40:50,040 --> 00:40:52,960 Speaker 2: the puzzle of a lot of human life that a 677 00:40:52,960 --> 00:41:00,080 Speaker 2: lot of would seem to be arbitrary. Rituals, conventions, hypocrisy 678 00:41:00,880 --> 00:41:05,279 Speaker 2: do have a hidden rationale in terms of either generating 679 00:41:05,680 --> 00:41:09,520 Speaker 2: or denying common knowledge, including all of the ways in 680 00:41:09,680 --> 00:41:16,400 Speaker 2: which we are systematically hypocritical, genteel, polite, dainty. We don't 681 00:41:16,920 --> 00:41:19,840 Speaker 2: blurt out things that all of us know privately but 682 00:41:20,000 --> 00:41:23,440 Speaker 2: we don't know commonly, and there's a reason for that. 683 00:41:23,520 --> 00:41:28,799 Speaker 2: It's necessary to preserve and retain certain social relationships on 684 00:41:28,800 --> 00:41:33,200 Speaker 2: which social life depends, and that, as certain comedies point 685 00:41:33,239 --> 00:41:36,759 Speaker 2: out where they envision a world in which someone or 686 00:41:36,800 --> 00:41:40,879 Speaker 2: everyone is forced to be honest. It quickly becomes a dystopia, 687 00:41:41,360 --> 00:41:43,759 Speaker 2: and the characters are glad to go back to a 688 00:41:43,800 --> 00:41:46,759 Speaker 2: state in which you don't say everything that you need. 689 00:41:51,520 --> 00:41:54,040 Speaker 1: That was my interview with Stephen Pinker. His new book 690 00:41:54,120 --> 00:41:58,680 Speaker 1: is called When Everyone Knows That Everyone Knows, Common Knowledge 691 00:41:58,840 --> 00:42:02,840 Speaker 1: and the Mysteries of Money, Power, and Everyday Life. The 692 00:42:02,880 --> 00:42:06,719 Speaker 1: book tackles many mysteries of life and psychology centered on 693 00:42:06,800 --> 00:42:11,600 Speaker 1: this question of how humans manage to coordinate on scales 694 00:42:11,640 --> 00:42:14,640 Speaker 1: that range from two drivers in a game of chicken 695 00:42:14,920 --> 00:42:18,480 Speaker 1: to millions of people in a nation. A lot of 696 00:42:18,480 --> 00:42:22,440 Speaker 1: the answers lie in this recursive loop of awareness that 697 00:42:22,480 --> 00:42:26,120 Speaker 1: we call common knowledge. Pinker shows us in the book 698 00:42:26,400 --> 00:42:29,240 Speaker 1: that common knowledge is at least some of the engine 699 00:42:29,280 --> 00:42:37,000 Speaker 1: behind laughter, applause, etiquette, trust, diplomacy, and financial markets. And 700 00:42:37,200 --> 00:42:41,160 Speaker 1: common knowledge is the difference between a thousand private doubts 701 00:42:41,480 --> 00:42:45,120 Speaker 1: and a public turning point in history. Private knowledge lives 702 00:42:45,120 --> 00:42:48,240 Speaker 1: in our skulls, but common knowledge spills into the shared 703 00:42:48,600 --> 00:42:53,880 Speaker 1: spaces between us, and it's what transforms isolated individuals into 704 00:42:53,920 --> 00:42:58,239 Speaker 1: a civilization. In our daily lives, we hardly notice it, 705 00:42:58,280 --> 00:43:01,120 Speaker 1: but every time that we have on the correct side 706 00:43:01,120 --> 00:43:04,040 Speaker 1: of the road, or laugh at the same moment in 707 00:43:04,080 --> 00:43:07,400 Speaker 1: the theater, or rise to our feet in a standing ovation. 708 00:43:07,520 --> 00:43:12,600 Speaker 1: We're participating in a recursive dance of shared awareness. The 709 00:43:12,640 --> 00:43:17,280 Speaker 1: thing that's so striking is how invisible it generally. 710 00:43:16,960 --> 00:43:17,560 Speaker 2: Is to us. 711 00:43:18,200 --> 00:43:23,719 Speaker 1: But common knowledge is the thread that binds strangers into 712 00:43:23,760 --> 00:43:33,719 Speaker 1: this mad, wild, beautiful collective that we call society. Go 713 00:43:33,760 --> 00:43:36,520 Speaker 1: to eagleman dot com slash podcast for more information and 714 00:43:36,640 --> 00:43:40,680 Speaker 1: find further reading. Join the weekly discussions on my substack 715 00:43:40,760 --> 00:43:43,640 Speaker 1: and check out Subscribe to Inner Cosmos on YouTube for 716 00:43:43,800 --> 00:43:47,480 Speaker 1: videos of each episode and to leave comments until next time. 717 00:43:47,560 --> 00:43:54,200 Speaker 1: I'm David Eagleman, and this is Inner Cosmos.