There is a value to shared knowledge that tends to go unrecognized because it's so ubiquitous. Nonetheless, experimental psychologist Steven Pinker explains in this Social Science Bites podcast, common knowledge underlies things like paper money, governance, and even coral reefs.
And common knowledge, he makes clear to host David Edmonds, "does not have its ordinary sense of conventional wisdom or an open secret or something that everyone knows, but rather something that everyone knows that everyone knows, and everyone knows that, and everyone knows that, and so on, ad infinitum."
Possing that shared knowledge – and the knowledge that others share that knowledge – creates the conditions for coordination, and thus action beyond what an individual could achieve. That's the reason, he says, "that autocrats fear common knowledge of the regime's shortcomings is that no regime has the firepower to intimidate every last citizen."
Pinker, the Johnstone Professor of Psychology at Harvard University, details his understanding of the virtues and vices of common knowledge in his most recent book, When Everyone Knows That Everyone Knows...: Common Knowledge and the Mysteries of Money, Power, and Everyday Life. The book, his 13th, continues his streak as one of the most publicly recognized of public intellectuals, including recognition as one of Foreign Policy's "World's Top 100 Public Intellectuals" and Time's "100 Most Influential People in the World Today." He is also only the second (so far) returning guest to Social Science Bites, having addressed violence and human nature in a 2012 podcast.