When Everyone Knows That Everyone Knows

Steven Pinker looks at common knowledge, which means everyone knowing something and also knowing that everyone else knows it. The book argues that this shared awareness is needed for coordination, such as driving on the right or using paper money, and for friendship, romance and authority. It also says people often avoid common knowledge, which leads to benign hypocrisy, veiled threats, innuendo and ignoring the elephant in the room. Pinker applies the idea to financial bubbles, sudden revolutions, diplomacy, shaming mobs and first dates, drawing on novels, jokes, cartoons, films and sitcoms.

Why You Should Read?

• Discover why, according to the book, people hoard toilet paper at the first sign of an emergency.
• Explore how the book links common knowledge to financial bubbles, revolutions that come out of nowhere and the pretense of diplomacy.
• Understand the signals the book says we use to create shared knowledge, such as laughter, tears, blushing and eye contact.
• Enjoy the novels, jokes, cartoons, films and sitcom dialogues the author uses to show the tragedies and comedies of social life.

About the Author

Steven Pinker was born on September 18, 1954, and is a Canadian who studies the mind as a cognitive psychologist and psycholinguist. He holds the Johnstone Family chair in psychology at Harvard University, and he speaks up for evolutionary psychology. His research covers vision and how children learn language. With Alan Prince, he argued that children sometimes misuse default rules but must learn irregular forms one at a time. His nine books for general readers include The Language Instinct (1994), The Better Angels of Our Nature (2010), which argues that violence has declined, The Sense of Style (2014) and Enlightenment Now (2018).