第4章
Rituals as Common Knowledge Generators
Why do cultures across time and geography develop elaborate public ceremonies? While anthropologists have traditionally focused on their symbolic meanings, Chwe argues that rituals serve a more fundamental purpose: creating common knowledge that enables coordination.
Consider royal processions in Elizabethan England, Javanese kingdoms, or Moroccan courts. While anthropologist Clifford Geertz analyzed these as expressions of a society's "master fiction," he missed their most obvious aspect - the large audiences they generate. These processions aren't primarily about spreading "ritual signs of dominance" like a wolf marking territory, but about creating common knowledge by ensuring each onlooker sees that everyone else is watching too.
Rituals create common knowledge through several mechanisms. The Ashanti practice of speaking grievances "before his face" (in public) transforms private grudges into common knowledge that can be publicly resolved. Repetition in rituals isn't just redundancy but makes the repetition itself apparent to all participants. As anthropologist Maurice Bloch notes, ritual's formalized language severely restricts possible meanings, creating certainty that generates authority by helping form common knowledge.
Multiple sensory channels - visual, auditory, kinesthetic - ensure participants experience the event intensely and simultaneously. Audience participation through call-and-response or group dancing "as a body" makes it immediately evident if anyone loses attention, further strengthening common knowledge.
Perhaps most fascinating is how spatial arrangements enhance common knowledge generation. Inward-facing circles appear across cultures precisely because they allow each participant to see that everyone else is paying attention. Archaeological evidence from prehistoric kivas in the southwestern United States shows circular, inward-facing structures with masonry benches along walls. Modern city halls like Fort Worth's use circular seating arrangements where "members of the audience would have visual contact with each other as well as the council," allowing them to observe collective responses.
Revolutionary festivals during the French Revolution featured circular amphitheaters that "enabled the spectators to share their emotions equally and to see one another in perfect reciprocity." The circle's effectiveness comes less from its symbolic meaning and more from its function as a communication technology that ensures mutual visibility.
第5章
Visual Storytelling: How Media Creates Common Knowledge
The power of common knowledge generation appears vividly in visual media, where shared experiences can create powerful collective understanding. The classic film "On the Waterfront" masterfully demonstrates how spatial arrangements create or prevent common knowledge among characters. The corrupt union gang's power is emphasized through their circular huddles - a visual metaphor for their tight-knit control and shared secrets. In contrast, the longshoremen's powerlessness is shown through their scattered positioning and deliberate avoidance of eye contact, symbolizing their inability to unite against oppression.
The film's pivotal moment arrives during Kayo Dugan's funeral in the ship's hold, which transforms into an amphitheater-like space with rising concentric rings of spectators. This becomes the first time the workers truly experience something together with common knowledge, creating a shared emotional catalyst for resistance. The physical arrangement mirrors ancient Greek theaters, where collective witnessing of events transformed individual knowledge into communal understanding.
Throughout the film, communication themes recur through sophisticated visual and auditory symbolism. The employers' power is represented by ship horns and whistles - forms of public communication that cannot be ignored. These sounds create instant common knowledge across the docks, demonstrating how authority maintains control through shared awareness. Meanwhile, characters physically block their sensory channels - covering ears, eyes, and mouths - in powerful visual representations of resistance to unwanted common knowledge, showing how people must sometimes actively reject information to avoid complicity.
This visual storytelling transcends mere artistic choice, reflecting a deep understanding of how power operates through common knowledge manipulation. The film demonstrates that coordination against authority requires not just individual courage but communal awareness - each person knowing that others know and are ready to act together. This principle appears in subtle ways, like characters watching others' reactions to gauge collective response, or the strategic use of public spaces versus private corners for different types of conversations.
Modern media has perfected common knowledge generation through mass broadcasts, taking these principles to a global scale. When millions watch the same Super Bowl commercial simultaneously, they not only receive the message but know that others are receiving it too - creating a shared cultural moment. This explains why certain events command premium advertising rates despite the availability of cheaper ways to reach the same number of people separately. Live events, award shows, and breaking news coverage create these moments of collective awareness that transform individual viewing into shared social experiences.
The impact extends beyond traditional media into social networks, where viral content creates instant common knowledge across vast audiences. When millions share and comment on the same video or meme, they're participating in a modern version of the amphitheater effect, where the knowledge that others are experiencing the same content becomes as significant as the content itself.
第6章
Advertising as Coordination: Why Companies Pay Premium Prices for Public Attention
Why would companies pay millions for a 30-second Super Bowl commercial when they could reach the same number of viewers through targeted ads at a fraction of the cost? The answer lies in common knowledge generation for products that benefit from coordination.
People prefer products others use for both technological reasons (network externalities make products like smartphones more valuable with wider adoption) and social reasons (wanting to discuss popular movies or serve recognizable beer). For newly introduced goods, consumers feel more comfortable purchasing when they know others are buying too.
Mass media not only distribute messages but let each receiver know about other receivers. The 1920s Listerine "halitosis" campaign exemplifies this approach, reaching 110 million readers monthly and increasing profits fortyfold. The campaign worked not just through individual communication but by creating common knowledge about a taboo topic that people wouldn't normally discuss.
Empirical evidence supports this theory. By analyzing 119 brands advertised on three U.S. networks, Chwe found that "social" goods (those a person is more likely to buy when others buy them) are advertised on more popular shows, and advertisers pay significantly more per viewer for these slots. After controlling for demographic characteristics, cumulative exposure, and seasonality, producers of social goods still pay approximately 20% more per thousand viewers than producers of non-social goods.
This explains why the Super Bowl has become the premier venue for introducing new products that benefit from immediate common knowledge, particularly network-dependent goods like credit cards, operating systems, and publicly consumed items like beer, cars, and clothing. Apple's famous 1984 Macintosh commercial wasn't just creative marketing - it was a strategic choice to create instant common knowledge among potential buyers facing compatibility concerns.
第7章
Social Networks: Why Strong Ties Matter for Coordination
The distinction between strong links (close friends) and weak links (acquaintances) presents a fascinating puzzle in social coordination. While weak links traverse society more efficiently (as demonstrated by the fact that any two Americans can be connected by just six weak links), strong links prove more effective for coordinated action. This phenomenon, first observed in Milgram's small world experiments, has profound implications for how communities organize and mobilize.
In networks with identical density, weak links connect people more widely while strong links create local clusters where friends of friends are also friends. For example, in a typical workplace, weak links might connect employees across departments, while strong links form tight-knit teams within departments. This creates a paradox: if coordination relies on communication speed, weak-link networks should be superior, yet evidence consistently shows strong links matter more for participation in collective action.
The solution lies in common knowledge creation. Strong links form triangular structures where each person knows their friends know each other, creating common knowledge locally. Consider a neighborhood association: when three close neighbors all know each other well, they can easily coordinate on community initiatives because each is confident the others will participate. In contrast, weak links might spread information widely but fail to create the mutual knowledge necessary for coordination. A person might hear about a community event through various acquaintances but lack the confidence that others will actually show up.
Using simple network models like the "square" versus "kite" structures, we can see that coordination succeeds in triangular structures where participants know their friends know each other, even when both networks have identical numbers of connections. The kite structure, despite having the same number of links, lacks the reinforcing triangular relationships that build trust and enable action. Real-world examples include successful labor movements, which typically emerge from tight-knit worker communities rather than loosely connected professional networks.
Strong links thus build communities not through quantity of connections but through their quality - creating neighborhoods where friends know each other rather than scattered city-center style relationships. This explains why close-knit communities can mobilize more effectively than loosely connected networks despite having fewer total connections. Religious communities, ethnic enclaves, and traditional villages demonstrate this principle: their dense internal relationships enable them to achieve remarkable levels of coordination for mutual aid, collective action, and social support, even with limited resources and connections to the broader world.
The implications extend beyond social movements to organizational design, online communities, and civic engagement. Successful communities often prioritize building strong internal bonds over expanding weak connections, recognizing that the depth of relationships matters more than their breadth for achieving collective goals.
第8章
Power and Surveillance: The Panopticon's Hidden Vulnerability
Jeremy Bentham's panopticon prison design features three key elements that revolutionized institutional surveillance: centrality (guards see all prisoners from one point), asymmetry (guards see without being seen), and separation (prisoners cannot see each other). While frequently analyzed as a mere surveillance mechanism, its relationship to common knowledge reveals deeper insights about power dynamics and social control that extend far beyond prison walls.
Bentham himself emphasized centrality and asymmetry over separation in his writings, even suggesting the design could work effectively without the partitions separating prisoners. This preference becomes particularly interesting when examining real-world implementations. At Stateville Correctional Center's Unit F, one of the few American panopticon implementations, prisoners could see both each other and the central guard tower - only centrality remained of Bentham's original triad. This real-world adaptation demonstrates how theoretical designs often evolve in practice.
While separation obviously prevents prisoner communication and coordination, and centrality provides efficiency through fewer guards, asymmetry serves a crucial function beyond making prisoners internalize surveillance - it prevents common knowledge formation among prisoners. This psychological element creates a state of constant uncertainty about observation, leading inmates to modify their behavior even when not actually being watched.
This becomes particularly evident through a feature Michel Foucault and later commentators largely ignored: Bentham's inclusion of a chapel above the inspector's lodge. The chapel transforms prisoners from mere surveillance objects into an audience, creating a dual purpose space for both observation and collective experience. This architectural element reveals how centrality facilitates both surveillance and ritual, suggesting Bentham understood the importance of maintaining certain forms of controlled collective experience.
Without asymmetry, the panopticon would essentially become theater-in-the-round, fundamentally altering its power dynamics. If guards were visible to all prisoners, any guard incapacitation - whether through illness, distraction, or attack - would create electric common knowledge among prisoners. Each prisoner would know that others see the same opportunity, potentially triggering coordinated action. Historical prison riots often began precisely when inmates realized guards had temporarily lost control, highlighting this vulnerability.
This fundamental weakness makes the panopticon inherently unstable; the price of surveillance efficiency is a structure easily "invertible." Unlike true atomization where each person experiences private surveillance, the panopticon creates common knowledge through sensory deprivation: each prisoner sees only the omnipresent tower and knows all other prisoners see it too. This shared experience of surveillance, paradoxically, creates a form of unity among the watched, making the watchers potentially vulnerable to collective action if their authority appears to waver even momentarily.
Modern surveillance systems have evolved to address these vulnerabilities through redundancy, electronic monitoring, and decentralized control mechanisms. Yet the panopticon's basic tension between efficiency and vulnerability remains relevant to contemporary discussions of surveillance and power structures.
第9章
Beyond Rationality vs. Culture: Bridging False Dichotomies
Western intellectual tradition has long maintained a distinction between rationality and irrationality, dating back to Aristotle's division between the "rational part" and "irrational part" of the soul. This manifests in contemporary scholarship through various dichotomies: reason versus culture, thinking versus feeling, calculation versus emotion.
This book challenges these distinctions by demonstrating that even narrow conceptions of rationality in coordination problems require common knowledge, which connects to intersubjectivity, collective consciousness, and group identity. The material-cultural distinction, rooted in Christian metaphysics' separation of base and spirit, breaks down when examined through the lens of coordination problems.
Game theory's application to symbolic action and culture isn't merely a side application but a necessary development in its internal agenda. By connecting individual rationality with cultural practices that create social unity, the book reveals their reciprocal relationship rather than antagonism.
This perspective transforms how we understand group identities. Benedict Anderson defines nations as "imagined communities" where members will never meet most fellow citizens, yet coordinate effectively because they share awareness of belonging to the same "language-field." Reading the morning newspaper constitutes a "mass ceremony" where each reader knows others are simultaneously consuming identical content.
Communication technologies shape these identity formations. Since the 1970s, advertising has shifted from mass marketing toward niche marketing through specialized media, creating what Joseph Turow calls "electronic equivalents of gated communities" that fragment society.
Symbolic events can transform group identities through common knowledge creation. When Nelson Mandela appeared in team uniform at the 1995 World Rugby Cup final in Johannesburg, this single collective moment transformed rugby from a hated symbol of apartheid into something all South Africans could celebrate. As Archbishop Desmond Tutu observed, "It said it is actually possible for us to become one nation."
第10章
The Mathematics of Common Knowledge: Making the Abstract Concrete
While common knowledge might seem like an abstract concept, it can be precisely modeled mathematically. Using payoff matrices and visual representations of knowledge states, we can analyze exactly how coordination succeeds or fails based on the structure of communication. Game theorists have developed sophisticated models showing how different levels of knowledge (I know, I know that you know, I know that you know that I know, etc.) create distinct coordination possibilities.
In the bus example, when two people face each other and both are awake, common knowledge exists, making successful coordination possible (though not guaranteed). The visual connection creates an infinite regression of mutual awareness - each person sees the other seeing them, creating the foundation for coordination. In contrast, when one person faces away, even if both hear the same announcement, successful coordination becomes impossible because they lack common knowledge of each other's awareness. This demonstrates how physical positioning and visual access critically affect coordination possibilities.
This is demonstrated through detailed payoff matrices and diagrams showing different equilibria. In the "successful equilibrium" when facing each other, both get off the bus (highest payoff, say 10 points each). In the "unsuccessful equilibrium," both stay on (moderate payoff, perhaps 5 points each). However, when one person faces away, the only possible equilibrium is both staying on the bus, because without common knowledge, the risk of getting off alone (worst payoff, -5 points) outweighs the potential benefit of coordination. These numerical values help quantify the precise trade-offs involved in coordination decisions.
Common knowledge isn't merely theoretical but empirically observable across multiple domains. In child development, research shows children around age seven can successfully answer complex questions about others' knowledge states and understand the difference between shared and private information. Animal cognition studies reveal that while chimps can follow gazes and understand what others see, they fail to grasp the impact of visual barriers like blindfolds, showing their limited grasp of knowledge states. In language use, psycholinguistic research demonstrates that speakers initially plan utterances without considering listeners' knowledge, only adjusting later in the process. Neuroscience studies have identified the "theory of mind module" potentially located in the orbitofrontal cortex, which activates when we reason about others' mental states.
The mathematical precision of common knowledge analysis doesn't diminish its human significance but enhances our understanding of how shared awareness shapes social coordination. This framework helps explain phenomena ranging from intimate conversations (where eye contact creates common knowledge) to national identities (where shared symbols and rituals establish common knowledge across large groups). Recent applications include analyzing social media dynamics, where "likes" and public comments create verifiable common knowledge, and studying how common knowledge affects market behavior and political movements. The mathematical approach also helps design better coordination mechanisms, from traffic signals to social platforms.
