One of the most useful ways to understand religion is to treat it as a way humans achieve social coordination. Steven Pinker’s recent work on common knowledge offers a sharp insight about this. Common knowledge is not merely that many people know something; it is the further fact that everyone knows that everyone knows it, and everyone knows that everyone knows that everyone knows it—in principle without end. This sounds like a philosopher’s game, but human beings handle it with surprising ease in daily life.
And it is not just an abstract curiosity. It is one of the practical tools that makes civilization possible. A simple way to grasp this is to compare private knowledge with common knowledge. Suppose I text you to meet me at a certain cafe at noon, but I am not sure whether you saw the message. My private intention does not coordinate anything unless I know that you know it too. Or take money: a paper bill has value only because I believe you will accept it, you believe I will accept it, and both of us assume countless other people will do the same. Without that shared expectation, it is only paper. Or think of driving through an intersection: I stop at a red light because I trust that other drivers know the same rule, and that they know I know it too. Without that layer of mutual expectation, there would need to be a police officer at every intersection and a supervisor at every transaction.
In Pinker’s framing, common knowledge generates coordination. It lets people converge on shared conventions—driving on the right, accepting paper currency, agreeing on a meeting place and time—without needing a central enforcer to micromanage every choice.
Once one starts seeing this, ordinary public events look different. A wedding is not only a private promise between two lovers; it is a public event in which everyone witnesses everyone else recognizing the couple’s new status. A graduation ceremony is not required to make learning real, but it does make achievement visible and socially undeniable. A courtroom oath, a citizenship ceremony, even the singing of a national anthem, all have a similar structure: they are not merely expressions of a belief or promise, but public demonstrations that everyone present has seen the same commitment made.
But the same logic also helps explain the shadow side of social life. People often avoid saying obvious things out loud because speaking them changes the situation. A whole family may privately know that a father is drinking too much, or that a marriage is failing, yet nobody mentions it at Thanksgiving dinner, because once it is said, everyone is forced to respond. Hypocrisy can sometimes be stabilizing in exactly this awkward sense: a church may publicly praise a strict moral rule while quietly knowing that many members do not live up to it, and the polite silence around the mismatch is part of what keeps the community from splitting apart. Shaming mobs ignite because once condemnation becomes visible—especially on social media—each person sees everyone else condemning too, and joining in suddenly feels safer and more rewarding. Revolutions can seem to erupt out of nowhere for a similar reason: thousands may privately resent a regime for years, but only when protest becomes public does each person realize that others were ready all along. And public rituals—religious, political, civic—have force because they do not merely express belief. They make belief mutually visible.
Religion is, among other things, a machine for manufacturing common knowledge. Private belief is psychologically real, but socially weak. It does not coordinate strangers. A society cannot run on invisible beliefs that no one can observe. What rituals do—prayer spoken aloud, communal singing, congregational responses, public confessions, initiation rites, sacred calendars, distinctive clothing, a crucifix necklace, shared dietary rules—is turn inner states into public signals. They convert “I believe” into “we can all see that we believe,” and then into “we all know that we can all see it.”
This matters because people are extremely sensitive to the social risk of being the odd one out. If belonging is the reward and ostracism the punishment, the most dangerous condition is uncertainty: Do they believe this? Do they know I believe it? Do they know I’m wavering? Rituals collapse that uncertainty. They make allegiance visible. They create an emotionally saturated version of a contract—less like signing a document, more like standing under a spotlight and letting the group watch you sign with your whole body.
This is why religions place such emphasis on public acts. Private prayer is meaningful to many, but communal prayer is socially decisive. Singing alone is esthetic; singing together is social glue. An individual moral intuition is fragile; a moral intuition recited in unison becomes harder to question, because questioning it is no longer just a solitary cognitive act—it becomes a social offense. And once a belief is entangled with common knowledge, its truthfulness often becomes secondary to its coordination-value. The belief may be fictional, but it is socially efficient.
This logic also helps explain why cost matters so much. A cheap signal is easy to fake. A costly signal is harder to fake, which is why social groups are so attracted to cost. High-demand religions—those that require many hours of weekly participation, tithing, conspicuous behavioural restrictions, sexual policing, or public displays of devotion—often look irrational or excessive from the outside. But through this lens, some of that irrationality is exactly the point. If a group can get you to do something inconvenient, stigmatizing, or effortful, it has a way to distinguish true loyalists from casual tourists. The sacrifice itself becomes evidence. The burden is part of the proof.
This is also why initiation rituals recur across wildly different human groups, religious and otherwise. The ordeal is a signalling device: I paid a price to be here; therefore I must value being here; therefore I am one of you. The group sees the price, and the price creates common knowledge of commitment.
Pinker makes an additional point that is deeply relevant to religious life: people do not always want knowledge to become common knowledge. They often go to great lengths to ensure that even if everyone privately knows something, no one is forced to acknowledge it publicly. Many communities function because people tacitly collude in not pressing certain questions to the point of explicitness.
Examples of this are everywhere. A family may quietly know that one relative has a severe drinking problem, yet conversation glides politely around it for years. A workplace may quietly know that a promotion was unfair, but no one wants to be the person who says so in the meeting. A teenager in a devout household may stop believing a doctrine years before saying it aloud, because the moment the words are spoken, the issue changes from an inner uncertainty into a relational crisis. Even in a congregation, several people may have serious private doubts about a sermon, a miracle claim, or a moral teaching, yet each person may assume that everyone else is more convinced than they are, and so the silence preserves the appearance of unanimity.
The moment a doubt is spoken plainly, it stops being a private flicker and becomes a social event. It demands response. It forces alignment. It threatens the shared story.
I can’t help thinking about the present political world. Within large partisan groups in parts of the world today, I suspect there are many private doubts about very alarming world events, and about the conduct of one very prominent leader who seems to dominate the news, yet too few people inside those groups are willing to speak their doubts aloud, because doing so would risk the loss of community. It reminds me of the old fairy tale The Emperor’s New Clothes. The force of that story is not that the child discovers some hidden fact. The child simply says aloud what everyone can already see. He turns private knowledge into common knowledge. Some of the truths of the current world situation, and of the behavioural problems of major leaders, are so obvious that a very young child could understand them clearly. Perhaps the innocence and humility of a child’s voice is exactly what is needed to pierce a collective performance of denial. One definition of heroism, in my opinion, is the willingness to speak one’s private knowledge of the truth to a group that may at least initially reject you for it.
In practice, a religious community often survives not by answering every question, but by managing which questions are acceptable to ask out loud.
Religious spectacles—miracles, exorcisms, dramatic conversions, speaking in tongues, revival meetings—are not just theological events. They are high-powered signalling events. They take a private feeling—“I felt something”—and turn it into a public fact: “We all saw her fall, shake, cry, speak strangely, rise transformed.” The group witnesses a performance that is emotionally contagious, and the witnessing itself becomes part of the evidence.
The crucial move is not merely that an unusual event occurs, but that everyone sees everyone else seeing it. This is how common knowledge is made at high speed: a shared spectacle that forces a shared interpretation, or at least a shared posture. If you stand in the room and do not respond, you are not merely unconvinced—you are socially deviant. The power of the event is partly the power of mutual surveillance.
This is also why sceptical outsiders often have a dual reaction to certain public charismatic performances: amusement at the apparent absurdity, mixed with unease at the very real influence such spectacles can have when they become fused to political power. The performance may look ridiculous, but its social function is very serious: it converts theatrical intensity into tribal certainty.
A frequent defence of religion is that it provides moral structure. That claim is not wholly wrong—at least at the level of group coordination. A community that repeats moral language weekly, that teaches children shared scripts for gratitude, restraint, charity, and self-scrutiny, will often produce decently socialized people. The group is continuously manufacturing common knowledge about what counts as admirable, shameful, or forbidden.
But this cuts both ways. It can coordinate kindness; it can also coordinate cruelty. When a group makes contempt for outsiders common knowledge—through sermons, jokes, or political messaging—the moral atmosphere shifts. People become emboldened. What was privately felt becomes publicly permitted. The difference between a prejudice that quietly lingers in someone’s mind and a prejudice that is openly shared is enormous: the second is actionable. It becomes policy. It becomes bullying. It becomes violence with a clean conscience.
One part of what we are seeing today in the rise of bullying and prejudice is this same effect: various groups are coordinating a social norm in which prejudicial thinking is shared openly within the community, until the prejudice itself becomes an emblem of partisan belonging.
The frightening historical efficiency of religious persecution is, in part, a story about common knowledge: it is easier to harm others when the justification has been made publicly shared, ritually repeated, and socially rewarded.
This dynamic is not only created in sanctuaries; it also spreads through networks. Here the work of Nicholas Christakis is a useful complement. His research suggests that behaviours can cascade through social networks—spreading from person to person to person, sometimes out to several degrees of separation. Human behaviour is not merely individual choice; it is often contagious.
Religion has always understood this intuitively. Congregations are network structures: friendship graphs with rituals attached. Conversion is rarely solitary; it is more often a relational event. People move toward belief because a trusted person pulls them toward a group in which belief is already visible and shared. Doubt spreads similarly: not primarily through reading an argument, but through watching someone you respect begin to question the sacred story. The moment that questioning becomes visible, it becomes socially thinkable. It becomes sayable. It becomes a potential cascade.
This is one reason religious authorities, across centuries, have been so preoccupied with public dissent. Private doubt is manageable; public doubt threatens contagion.
The “New Atheist” era often tried to treat religion as though it were primarily a set of factual claims—claims that could be refuted, one by one, by geology, evolutionary biology, textual criticism, or cosmology. Those refutations matter. But they often fail to persuade for the same reason a spreadsheet rarely defeats a love affair: the object is not merely an idea; it is a social world.
If religion is partly a technology for manufacturing common knowledge—about belonging, virtue, status, and identity—then a purely evidential critique will bounce off the surface for many people. The deeper structure is social. To leave a religion is not only to change one’s beliefs; it is to risk becoming unintelligible to one’s own tribe. In the harshest cases, it is to risk exile. The mind treats that as a danger.
This also helps explain why political leaders so often perform religiosity even when their lives show little evidence of it. Performance creates common knowledge. A staged photo with a sacred symbol is not primarily addressed to God; it is addressed to the crowd. It signals, “I am one of us,” and it invites the crowd to become complicit in acting as though that were obviously true. Once that performance becomes socially established, dissenters inside the coalition pay a price for pointing out the obvious.
Therefore, the secular task is not only to critique supernatural claims. It is also to build non-supernatural forms of common knowledge that can do some of the same social work. Something like this is already happening in the modern world. People gather around causes, institutions, professions, civic rituals, scientific identities, mutual aid networks, even exercise cultures. These can be silly or beautiful, freeing or authoritarian. The point is not that secular life lacks ritual. It is that secular rituals are often fragmented, unstable, less grounded in family history and ethnic continuity, and less explicitly oriented toward moral formation. Secular life is not short of art or beauty. What it often lacks is a comparably thick set of shared rituals that bind esthetics, morality, ancestry, and public belonging all at once.
Religion persists not only because people are credulous or fearful, but because religion solves hard social problems. Pinker’s concept of common knowledge helps explain how it solves them—sometimes in ways that elevate human life, sometimes in ways that deform it. And once one sees religion as a social technology of visibility—of signals, rituals, and shared scripts—one can critique it more honestly: not as a childish mistake, but as an ingenious human invention that exacts a price.
The deeper question is whether we can build a life, and a society, in which the best human goods that religion has traditionally coordinated—community, moral aspiration, awe, mutual care—can become common knowledge without requiring that we pretend, together, that comforting fictions are facts.
