Sapiens
A Brief History of Humankind
The big idea
What let humans conquer the planet isn't raw intelligence or tools — it's our unique ability to believe in shared fictions. Money, nations, laws, and companies don't exist in nature; they exist because millions of strangers agree to act as if they do.
Why it matters
A chimp can't be persuaded to give up a banana now for a reward in some imagined afterlife — but humans can, because we can invent and collectively trust stories. That's what lets us cooperate flexibly in groups of millions. A banknote is just paper; it works only because we all share the same story about it. Harari calls these “inter-subjective” realities: real because enough people believe them, the way the rules of chess are real.
Use it today
Pick one “solid” thing you take for granted — your company, the money in your account, a national border — and ask what's actually holding it up. Almost always the answer is collective belief, not physical fact.
Drop it in conversation
“It's wild when you think about it — money only works because everyone agrees to pretend it has value. The whole economy is basically a shared story we all decided to believe.”
In real lifeA banknote is just printed paper and a company is just a document in a filing cabinet — yet both move the world, purely because millions of us agree to treat them as real.