‘When Everyone Knows That Everyone Knows…’: A game of brains

(Image: WSJ)

Sun, 05 Oct 2025

By Dominic GreenThe everyday meaning of “common knowledge” is knowledge held in common, often as an open secret. For example, it is common knowledge that publishers like books that seek, via quirky examples, to explain all life through a single social-science theory. This everyday meaning appears in Steven Pinker’s “When Everyone Knows That Everyone Knows ...,” but it is not what he has in mind.Mr. Pinker is an evolutionary psychologist and, despite being a Harvard professor, the author of many serious and rea...

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