# Ep69 "Why We Don't Just Say What We Mean" with Steven Pinker Source: https://www.youtube.com/watch?v=13_klHZxJNo Recap page: https://rapidrecap.app/video/13_klHZxJNo Generated: 2025-12-18T21:33:26.173+00:00 --- ## Quick Overview Steven Pinker argues that the common knowledge assumption—where everyone knows that everyone knows a piece of information, like the Roman Emperor not wearing clothes—is a crucial, yet often overlooked, element of human behavior, especially in social dynamics, political regimes, and even in mathematics like game theory, because this shared awareness dictates how people act and coordinate, often leading to self-censorship or manufactured public agreement even when private knowledge contradicts the consensus. **Key Points:** - The concept of common knowledge, where everyone knows that everyone knows something, is a fundamental driver of human behavior across social, political, and mathematical contexts. - Pinker cites the example of the Roman Emperor not wearing clothes, where the tacit agreement to pretend he is clothed maintains a societal equilibrium that direct contradiction would shatter. - In political regimes, like dictatorships, this common knowledge equilibrium often involves people publicly conforming to the dictator's narrative while privately knowing it is false, fearing being the first to break ranks. - The ability to engage in complex coordination, such as in marriage contracts or economic exchanges, relies on shared knowledge assumptions about mutual intent and beliefs. - Cognitive psychology suggests that humans are naturally adept at tracking these nested beliefs (I know that you know that I know...), which is essential for social interaction. - The failure to maintain common knowledge—or the fear of being the first to expose a shared secret—is what often prevents collective action or truth-telling in oppressive systems. - Pinker suggests that education, particularly in areas like game theory and logic, can help people recognize and sometimes break these common knowledge equilibria. ![Screenshot at 00:23: The opening title slide clearly identifies the speaker as Steven Pinker, Johnstone Family Professor of Psychology at Harvard University, discussing 'The Science Behind Why We Don't Just Say What We Mean - Part 1,' setting the stage for a deep dive into the psychology of communication and belief structures.](https://ss.rapidrecap.app/screens/13_klHZxJNo/00-00-23.png) **Context:** This is Part 1 of an interview between Jonathan Berke of the Lauder Institute and Steven Pinker, Johnstone Family Professor of Psychology at Harvard University, discussing Pinker's book on 'The Science Behind Why We Don't Just Say What We Mean.' The conversation centers on the concept of common knowledge—a formal, logical concept extended from mathematics and game theory—and its profound implications for understanding why individuals often fail to express their true private beliefs in public settings, particularly under oppressive social or political structures. ## Detailed Analysis Steven Pinker explains that the reason people often do not say what they mean stems from the powerful social mechanism of common knowledge, which he defines as a piece of information that everyone knows, and everyone knows that everyone knows, and so on, infinitely. He uses the example of the Emperor’s New Clothes, where the collective silence about the Emperor being naked is maintained because no one wants to be the first person to break the tacit agreement and risk social repercussions or even official reprisal. This concept is crucial because it underpins coordination in human behavior, from simple politeness like asking someone to pass the salt, to complex social structures like marriage contracts or political regimes. Pinker notes that while individuals might privately know the truth (e.g., the Emperor is naked, or the dictator is illegitimate), the fear of being the one to break the common knowledge equilibrium—the fear of being the first to admit guilt or challenge authority—keeps them silent. This mechanism is particularly relevant in totalitarian systems where the cost of challenging the official narrative is extremely high, resulting in widespread, shared deception that appears stable only as long as everyone maintains the pretense. Pinker suggests that understanding this logic, which is rooted in cognitive science and game theory, can help individuals recognize when such equilibria are fragile and when collective action might be possible. ### Introduction and Guest Background - Welcome to the Lauder Institute podcast with Steven Pinker, Johnstone Family Professor of Psychology at Harvard University, discussing his book on why we don't say what we mean - The concept of common knowledge is introduced as the central theme. ### Defining Common Knowledge - Common knowledge is defined as information everyone knows, everyone knows that everyone knows, and so on infinitely, contrasting it with private knowledge - The Emperor's New Clothes story is used as the primary illustration of this phenomenon. ### Common Knowledge in Social/Political Contexts - Pinker explains how common knowledge applies to political regimes (like dictatorships) where public statements contradict private beliefs - The equilibrium is maintained by the fear of being the first to speak out, risking punishment or social exclusion. ### Game Theory and Coordination - The concept is essential for coordination in rational parties, like in marriage contracts or economic deals, where mutual expectations must be shared - This highlights the function of common knowledge in facilitating cooperation when direct communication is risky. ### Conclusion and Future Episodes - The discussion concludes by noting that while the concept is ancient, its application to human behavior is still being explored - The hosts announce the next episode will further explore this topic. ![Screenshot at 00:06: The host introduces Steven Pinker, Johnstone Family Professor of Psychology at Harvard University, who is the subject of the discussion regarding his book on communication and belief.](https://ss.rapidrecap.app/screens/13_klHZxJNo/00-00-06.png) ![Screenshot at 00:38: Steven Pinker introduces the topic by referencing his book, which explores the science behind why people do not always say what they mean.](https://ss.rapidrecap.app/screens/13_klHZxJNo/00-00-38.png) ![Screenshot at 01:04: The host introduces the core concept of the discussion: 'When everyone knows that everyone knows' \(Common Knowledge\).](https://ss.rapidrecap.app/screens/13_klHZxJNo/00-01-04.png) ![Screenshot at 02:22: The host uses the analogy of the Emperor not wearing clothes to illustrate how common knowledge maintains a false public consensus.](https://ss.rapidrecap.app/screens/13_klHZxJNo/00-02-22.png) ![Screenshot at 03:00: Steven Pinker discusses the relevance of common knowledge in challenging situations, like the execution of Nicolae Ceaușescu, where people feared being the first to act against the regime.](https://ss.rapidrecap.app/screens/13_klHZxJNo/00-03-00.png)