Seventy thousand years of being human

About seventy thousand years ago, something shifted in the way human minds worked. Yuval Noah Harari calls it the Cognitive Revolution, and argues it was less about bigger brains than about a new capacity: the ability to believe in things that don't physically exist. Laws, money, gods, nations — none of these are real in the way a stone or a river is real, yet they coordinate the behaviour of millions of strangers who have never met and never will. This capacity for collective fiction, Harari argues, is what separates Homo sapiens from every other species that has ever lived on this planet.

That shared capacity for fiction, Harari contends, is what allowed Homo sapiens to cooperate at scales no other animal manages. A chimpanzee troop is limited by the number of individuals who can maintain personal relationships — perhaps a few dozen. Humans can march in armies of thousands, build cities, and run global supply chains precisely because strangers share belief in abstract entities — a currency, a flag, a legal system — and act accordingly without personal acquaintance.

The Agricultural Revolution, which Harari describes as history's biggest fraud, complicates the triumphalist story. Farming produced surplus and eventually civilisation, but for most individual humans it meant harder work, worse nutrition, and greater vulnerability than foraging had provided. Wheat didn't serve humanity so much as humanity served wheat, spreading the plant across the planet in exchange for a considerably harder life — more calories, fewer varieties, far more labour.

Harari then examines how money, empires, and religion each served as unifying forces that allowed ever-larger groups of strangers to coordinate behaviour under shared systems of belief and expectation. He is particularly interested in how these systems became self-reinforcing over time: the stories people tell about money make money work, which confirms the stories and gives them further power. The imagined order and the social order become effectively indistinguishable from each other across generations, which is why they are so difficult to see clearly from the inside.

The Scientific Revolution, in Harari's telling, rested on a particular kind of intellectual humility: the willingness to say 'we don't know yet.' Sending ships into unknown oceans requires believing the map is incomplete and that completing it is possible. Earlier, more cosmologically settled cultures were less inclined to accept that kind of open ignorance as productive. Europe's willingness to couple admitted ignorance with organised inquiry — and to finance that inquiry with empire — was the motor of modern power.

The book is deliberately vast, and that vastness is part of its appeal. Harari is writing something closer to a unified theory of the human animal than to conventional history. Whether or not every argument convinces, the questions it forces — what are we, what holds us together, what are we doing to ourselves — are worth sitting with seriously. The book has sold tens of millions of copies worldwide and made Harari one of the most widely read historians of his generation. These are among the most important questions any species has ever faced.