Peter Zhang



Sapiens by Yuval Noah Harari tells the story of the human race. It’s a case study in deep history, drawing on evolutionary biology, psychology, and the social sciences to explain how we got here and where we might be headed. It’s a broad, insightful narrative with interesting takes and speculations.

Here’s the paperback and audiobook.

Utility: ★★★✰✰ (3/5)

Writing: ★★★★✰ (4/5)

I enjoyed the writing style. Harari keeps book entertaining, drawing in relevant examples and present implications of long-ago events. The book also includes beautiful, full-color snapshots that really enhance the story—well done!

I worry, however, that the entertainment comes at the expense of historical and scientific accuracy. His accounts of American colonization and several drive-by accounts of modern science are over-simplified and ridden with mistakes.

More generally, Harari is an ideologue (or a “hedgehog, as Tetlock would put it), inferring broad, deterministic structures from a handful of examples. In that regard, his work echoes Jared Diamond’s geographic determinism in Guns, Germs, and Steel. But unlike Diamond, and even more frustratingly, Harari refuses to take a stance on the precise form and function of these structures—science, capitalism, industrialism, religion—making his theories utterly unfalsifiable. I don’t buy it.

A final frustration is his tendency to jump ship and dive into loosely connected tangents. I get that his goal is to talk “deep history,” but why a random offshoot into the psychology of happiness? Is 20 pages enough to map out the future of Sapien life? I walk away with vague impressions and little concrete knowledge. If you’re not into deep dives, I wouldn’t recommend it.


I read through the book a second time to take notes. It takes a lot longer, but the notes are much more condensed and I get to focus on the big picture. I also included footnotes for personal commentary; check them out!


How years old is it?

  • Universe—13.8 billion.
  • Earth—4.5 billion.
  • First organism—3.8 billion.
  • First human….—2.5 million.
  • …in Eurasia—2 million.
  • …using fire—300,000.
  • First homo sapiens—200,000.
  • Cognitive Revolution—70,000.
  • Settlement of America—16,000.
  • Agricultural Revolution—12,000.
  • First kingdom—5,000.
  • Scientific Revolution—500.
  • Industrial Revolution—200.

The Cognitive Revolution

For millions of users, Sapiens were indistinct from the other Homos. Only 12,000 years ago did we either extinguish or assimilate our cousins—Neanderthalenisis, Erectus, Soloensis, Floresiensis, Rudolfensis, Ergaster. Sapiens are a mere evolutionary anomaly, since bigger brains (counterproductively) require more fuel.

The invention of fire was crucial, facilitating digestion and empowering human control over environments. The real key, however, was language, letting humans communicate detailed information, gossip about other humans, and create collective fictions. Myths unlocked broad social cohesion—a group can’t stay intimately connected after 150 individuals, but they can share a faith, explaining why only Sapiens participated in trade.

The social structure of our ancestors is largely a mystery. We can’t extrapolate from modern forager societies, which live in rough environments, vary significantly, and are influenced by industrial societies.1 We do know that bands were tight-knit, flexible, and worked relatively little; they sometimes had a dark side too, abandoning the old or disabled. Foragers tended to be animists, believing that nothing separated humans from other beings. There is varying evidence for rates of peace and war, although hostility likely varied by society.2

Early humans wiped out large mammals. Indonesians living 45,000 years ago voyaged to Australia and extinguished its giant species within a few thousand years. Climate-based explanations are implausible because of the short time frame, survival of sea creatures, and similar extinctions on other continents. The same story repeated itself in the Americas, Madagascar, and the Pacific Ocean.

The Agricultural Revolution

Agriculture was no panacea. As agriculture emerged across the world, farmers were trapped in brutal , boring, violent, and equally tenuous lives. Although the lifestyle oppressed individuals, women in settled societies could have more children, giving agriculture an evolutionary edge. To assist them, humans domesticated animals and brought them across the globe, usually subjecting them to even more brutal conditions.

Food surpluses, transportation systems, and collective myths coalesced to form the first societies. Whether it’s Hammurabi’s Code or the Declaration of Independence, mass societies depend on figments like justice, equality, and human rights to function. Of course, there are true believers—die-hard Christians drove the expansion of Christianity—but these myths entrap the majority through material enforcement, reshaping desires, and collective pressure.

Larger societies produced mounds of information beyond human comprehension. At first, empires used partial scripts to administer taxation systems. It took until 2,500 BC before the Sumerians developed cuneiform, a full script, which could express the entirety of human speech.

Both Hindu castes and American Jim Crow are products of self-reinforcing social structures. Discrimination produces material inequalities, thereby legitimizing the belief. Womanhood is also a social imagination. Patriarchy can’t be explained by men’s physical dominance, aggression, or evolutionary selection; its origins remain a mystery.


Every culture is in flux, oscillating between contradictory values (think: equality and freedom). Cultures also tend to clump, amalgamating as they intersperse across the globe. There are three universal orders.

The first is money. Barter economies suffered from confusing conversion ratios and mismatched preferences. Shells—the first form of money—gave merchants a medium of exchange, later replaced by coins and paper cash. Money was infectious: even if your dollar bill is just paper to my society, the very fact that I can use it to purchase your goods gives that paper value.3

The second was empire, defined as distinct peoples united under a nation with flexible borders. Empires have dominated the world for millennia, providing stability and prosperity. For ease of administration and legitimacy, empires went through the painful process of assimilating conquered cultures. Disavowing empire is cathartic but irrational: pre-imperial cultures are often products of empires past, and confronting tomorrow’s challenges will require even greater unity.

The third was religion. Gods may have emerged to explain arbitrary factors like climate or epidemics.4 Polytheists, from the Greeks to the Hindus, believe that gods don’t care about human affairs. Christianity’s breakthrough was its fanatical and missionary nature, displaying both monotheistic (believing in one all-powerful god) and dualist (pitting God against Satan) qualities. In modernity, ideologies like Communism are new religions—a system of norms and values based on belief in a superhuman order.

But why did a particular system, like English or Christianity, come to power? Explanations suffer from hindsight bias: in 0 A.D., it would’ve been impossible to foresee that J.C. would rule the world.5 There’s also no telos to humanity, no promise that history will trend towards human flourishing.

The Scientific Revolution

Science has unlocked tremendous human power. It relies on modesty, rigor, and new technology to solve problems from electricity to poverty. But science lacks a telos; the research we choose to fund depends on value judgements from society.

Europe led the scientific revolution because of their willingness to admit ignorance: its legacy includes Darwin, Columbus, and the mapmaker Waldseemüller. Science enabled European empires to conquer the world. Although empires used science to justify racial hierarchies, they also founded linguistics, botany, geography, and history: science is neither good or bad.

Empires benefitted from capitalism too. Adam Smith’s insight was that individual greed expands collective welfare. Capitalism promotes the provision of credit and reinvestment of profits into production. The connections to empire are deep: both Columbus’ voyage and the VOC began as investment pitches. Free-market capitalism produces inequality when left unchecked, and endless growth may soon run up against resource constraints. In response, capitalism finds new raw materials and induces demand in consumers.6

Modern individualism replaces the nuclear family with the state and market. We create imaged communities, such as “Americans” or “Berkeley students.” These social transformations took place amid tremendous peace and tranquility, attributable to nuclear deterrence, diminished returns, and a peace-loving elite.

The growth in power has no clear relationship to happiness. Beyond the “power is progress” and “power corrupts” narratives, we must consider inequality, ecological limits, and the suffering of animals. Happiness is connected to our expectations: compared to the models in advertisements, we don’t look so hot. Research suggests that on an individual level, happiness is mainly determined by biochemicals.7 But, we need not resign to happiness-inducing drugs or search for a deeper “meaning of life”—the Buddhists instruct us to simply divorce our feelings from our happiness.

New biotechnologies could alter the fate of the species. First, genetic engineering has already been performed on human fetuses. Second, cyborg technology are being researched by the military and can already assist people with disabilities. Third, artificial intelligence could soon craft a new class of conscious beings.8 We ought to start thinking about these futures.


  1. I love historians that pay careful attention to causal mechanisms and confounding factors. Modern foragers overwhelmingly live in secluded, resource-constrained areas because those are the ones who haven’t been consumed by industrial society. The story reminds me of the SRG in World War II, studying bullet holes in planes

  2. Steven Pinker’s The Better Angels of Our Nature depicts savage ancient societies, while Jared Diamond’s Guns, Germs, and Steel argues precisely the opposite. Harari’s middle ground seems eminently reasonable. 

  3. One of my favorite podcasts, Hidden Brain, has a great episode about emotional currency. Against the “medium of exchange” theory, anthropologist Bill Maurer points out the lack of evidence for direct barter. Instead, Maurer thinks that money originated as a way to tie people together via social obligations, a physical “IOU.” 

  4. Today’s “God of the gaps” shows traces of this ancient origin. God is invoked to explain whatever science has not yet mastered. Historically, that meant everything from natural disasters to the planets. God’s explanatory domain has since retreated to the margins: the hard problem of consciousness, the origin of the universe, and the origin of life. 

  5. Phillip Tetlock’s Superforecasting is the Bible of prediction. It turns out that predicting future events is a whole lot harder than explaining past events. 

  6. The tension between capitalism and ecological limits is a hotly debated subject in the degrowth literature. Harari seems to hold faith in decoupling; I think he needs to justify his view. 

  7. Biological determinism vis-à-vis happiness is challenged by Shawn Achor in The Happiness Advantage—review coming out soon! 

  8. I don’t think Harari understands the distinction between artificial intelligence (already widespread, somewhat dangerous) and artificial general intelligence (extinction risk, definitely not coming soon). 

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