Sapiens: A Brief History of Humankind

An animal of no significance

Yuval Noah Harari tells the story of our species in four parts. He frames it around three revolutions. The Cognitive Revolution, about 70,000 years ago, started history. The Agricultural Revolution, about 12,000 years ago, sped it up. The Scientific Revolution, about 500 years ago, may end history as we know it and start something new.

He begins by placing us in nature. Humans are animals. The genus Homo first evolved in East Africa about 2.5 million years ago. For most of that time, several human species lived at once. Homo neanderthalensis lived in Europe and western Asia. Homo erectus spread across eastern Asia. Smaller species lived on islands such as Java and Flores. Our own species, Homo sapiens, appeared in East Africa much later.

Early humans had large brains, walked upright and used tools. Yet for a long time they were not at the top of the food chain. They were middle-ranking animals that often scavenged what larger predators left behind. Big brains were also expensive. They used a large share of the body's energy and made human babies helpless for years. This forced humans to live in close social groups.

The domestication of fire gave humans an edge. Cooking made food easier to digest, which may have allowed smaller guts and bigger brains.

Then Sapiens spread out of Africa, and the other human species vanished. Harari presents two theories. The Interbreeding Theory says Sapiens mixed with other species. The Replacement Theory says Sapiens pushed them out, perhaps violently. Genetic evidence shows some mixing: many people today carry a small share of Neanderthal DNA. But Harari argues that the other species still disappeared, and Sapiens was likely the cause.

The Cognitive Revolution

Why did Sapiens win? Harari's answer is language, and one feature of it above all. Between about 70,000 and 30,000 years ago, Sapiens began to think and communicate in new ways. He calls this the Cognitive Revolution. Its cause is unknown. Harari suggests a possible genetic change in brain wiring, which he calls the Tree of Knowledge mutation.

Many animals communicate. What makes Sapiens language special is two things. First, it allows gossip. People can share detailed information about who is trustworthy, which helps groups grow and cooperate. Second, and more important, it allows fiction. Sapiens can talk about things that do not exist: spirits, gods, nations and laws.

This ability to believe in shared stories is what lets large numbers of strangers cooperate. Harari notes that groups bound only by personal knowledge tend to max out at about 150 people, a figure known as Dunbar's number. Beyond that, you need common myths.

His example is Peugeot, the car company. Peugeot is not its factories, cars or workers. All of those could vanish and Peugeot would still exist as a legal entity. It is a legal fiction, a story that lawyers and courts agree to treat as real. Harari calls such things imagined realities. Money, human rights, nations and corporations all belong to this category. They exist because many people believe in them together.

From this point on, Harari says, history replaces biology as the main driver of human change. Sapiens can change its behavior quickly by changing its stories.

He then describes the lives of foragers. For most of human history, people lived in small bands that hunted and gathered. Harari argues that many foragers had a more varied diet, fewer infectious diseases and shorter working hours than later farmers. They also faced high child mortality and violence. Their religion was likely animism, the belief that places, animals and plants have spirits.

Foragers were not gentle with nature. When Sapiens reached Australia about 45,000 years ago, most of its large animals soon disappeared. Similar waves of extinction followed in the Americas and on islands. Harari calls this the first wave of extinction and describes Sapiens as an ecological serial killer.

The Agricultural Revolution

About 12,000 years ago, humans began to farm. The usual story treats this as progress. Harari calls it history's biggest fraud.

Farming did increase the total amount of food. It allowed many more people to live. But for the average person, life often got worse. Farmers worked longer hours. Their diet became narrower and less healthy. They suffered more disease from living close to animals and each other. They depended on a few crops, so a single drought could bring famine. Elites took the surplus.

Harari reverses the usual view of who domesticated whom. Wheat was a wild grass in the Middle East. Today it covers huge areas of the planet. In his telling, wheat domesticated humans, not the other way around. People cleared fields, carried water and pulled weeds for it, and they gave up a freer life to do so.

Why did people accept this? Harari points to the luxury trap. Each small step seemed to make life a little easier. Over generations, the steps added up, and no one could go back.

He also cites Göbekli Tepe, a monumental site in Turkey built by foragers before farming took hold. It suggests that shared beliefs may have pushed people toward agriculture, not the reverse.

Farming produced kingdoms, armies and trade networks. To hold them together, rulers needed imagined orders. Harari compares the Code of Hammurabi with the American Declaration of Independence. Both claim to rest on universal truths. Both describe orders that exist only in human belief.

Writing grew out of the need to manage these orders. The Sumerians developed a script for taxes, debts and property. One of the first names in recorded history, Kushim, appears on a tablet that records a quantity of barley. Writing let bureaucracies store far more data than any human memory.

Imagined orders also created hierarchies. Harari examines the Hindu caste system, race in American history and gender. He argues that most hierarchies rest on stories, not on biology, though they often claim to be natural.

The unification of humankind

The third part argues that history moves toward unity. Small cultures merge into larger ones. Harari names three universal orders that made this possible:

• Money, the economic order.
• Empire, the political order.
• Universal religions, the religious order.

Merchants, conquerors and prophets were the first to imagine the whole world as one unit.

Money is the most universal system of mutual trust ever made. Harari traces it from barley used as money in Sumer, to silver, to coins. Money works because everyone believes everyone else believes in it. Two people who share no language, religion or customs can still trade.

Empires ruled many peoples with different cultures. Harari argues that most humans in history have lived in empires. Empires were often brutal. But they also spread languages, laws and ideas, and much of today's shared culture comes from them.

Religions moved from local spirits to universal claims. Harari traces animism, polytheism, monotheism and dualism, then natural-law religions such as Buddhism. He also classifies modern ideologies, such as liberalism, socialism and nationalism, as religions, because they rest on shared beliefs in a superhuman order. He calls liberal, socialist and evolutionary humanism forms of humanist religion.

Harari ends the section with a warning about hindsight. History looks inevitable only after the fact. He calls it a "level two" chaotic system: predictions about it change the outcome. He also says there is no evidence that historical change benefits humans.

The Scientific Revolution

The last 500 years transformed human power. Harari says the Scientific Revolution began with a discovery of ignorance. Earlier traditions claimed to know everything important. Modern science starts by admitting what it does not know. It then uses observation and mathematics to gain new knowledge, and it ties that knowledge to new power.

He uses maps as a symbol. Older maps filled unknown areas with imaginary places. European maps from the 1500s began to leave blank spaces. Those blanks invited exploration.

Science grew alongside empire and capitalism. Harari describes how European empires funded science because it gave them power. Scientific expeditions, such as James Cook's voyage to the Pacific, carried astronomers and botanists along with soldiers. The knowledge they gathered helped European states conquer and rule.

The capitalist creed rests on credit, which is trust in the future. If people believe the economy will grow, lenders fund new ventures, and the belief helps make growth real. Harari draws on Adam Smith's idea that profits reinvested in production benefit society. He also shows the dark side, such as financial bubbles and wars fought to protect trade.

The Industrial Revolution solved the energy problem. Steam engines turned heat into motion. Later machines converted energy in more and more ways. Production soared. Harari points to the cost paid by farm animals in industrial agriculture. He also shows how a new ethic of consumerism arose to make sure people bought everything that factories made.

Modern life also broke old communities. For most of history, family and village met most human needs. Today the state and the market take their place. People gain freedom as individuals but lose close ties. Harari also notes a striking fact: in recent decades, wars between major states have become much rarer.

Happiness and the end of Homo sapiens

Harari asks whether all this power has made people happier. He finds no clear answer. Wealth and health matter, but expectations rise with them. Biologists argue that happiness depends largely on brain chemistry. Others argue it comes from seeing meaning in life. Buddhism, he notes, says suffering comes from craving itself, so the key is to stop chasing feelings.

He closes by looking ahead. Science may soon replace natural selection with intelligent design by humans. He names three paths: biological engineering, cyborg engineering and the creation of inorganic life, such as advanced software. Each could change what it means to be human. Harari suggests that Sapiens may be replaced by something that is no longer Sapiens.

In the afterword, he calls humans an animal that became a god. We have enormous power but little sense of what we want. He argues that the most important question is not what we can become, but what we want to become.

What the critics say

Many historians and anthropologists say the book trades depth for sweep. They argue it simplifies complex debates, states speculation with too much confidence and contains some errors of detail. The claim that farming was a fraud and the picture of forager life are both contested. Critics also note that its idea of fiction is very broad, which makes it hard to test.

Who should read it

Read it if you want one big story of the human past that connects biology, economics, religion and politics. It suits curious general readers who enjoy bold arguments and are willing to question them.