Book Summary: Sapiens (Part 4)

This is Part 4 (The Scientific Revolution) in the four-part series of book summary of Sapiens by Yuval. If you haven’t read Part 1 (The Cognitive Revolution)Part 2 (The Agricultural Revolution), Part 3 (The Unification of Humankind), please read them before reading this.

The Scientific Revolution

14) The Discovery of Ignorance

  • The last 500 years have witnessed a phenomenal and unprecedented growth in human power.
  • Population has grown 14x, production has grown 240x, and energy consumption has grown 115x.
  • Development of the atomic bomb in 1945 not only changed the course of history, but also gave humankind the capability to end it.
  • Humans have increasingly come to believe that they can increase their capabilities by investing in scientific research.


  • One difference between religion and science is that science assumes humankind does not know the answers to many of life’s biggest questions. Religion, however, assumes that the important stuff is already known. Science assumes human ignorance.
  • Modern science is built upon a willingness to admit that we do not know, the centrality of observation and mathematics, and the acquisition of new powers.
  • Ancient traditions of knowledge only admitted two kinds of ignorance: An individual may be ignorant to something important, or an entire tradition might be ignorant of unimportant things.
  • Modern-day science is a unique tradition of knowledge, inasmuch as it openly admits collective ignorance regarding the most important questions.

The Scientific Dogma

  • Previous cultures and belief systems compiled their theories using stories. Science compiles its theories using mathematics.
  • Knowledge is connecting observations with mathematical theories.
  • In medieval Europe, logic, grammar and rhetoric formed the educational core. Today’s students study mathematics and other exact sciences.

Knowledge is Power

  • Not everybody understands quantum mechanics, cell biology, or macroeconomics. Nevertheless, we all benefit from the power science gives us.
  • Scientists generally agree that no theory is 100 percent correct. Thus, the real test of knowledge is not truth, but utility. A theory that enables us to do new things constitutes knowledge.
  • Napoleon’s troops, led by all his tactical genius, still wouldn’t stand a chance against an inept general with modern weaponry.
  • Gunpowder was invented in China 600 years before cannons became a decisive factor in battle. The Chinese used the new compound for firecrackers.
  • Science, industry and military technology intertwined only with the advent of the capitalist system and the Industrial Revolution.

The Ideal of Progress

  • Until the Scientific Revolution most human cultures did not believe in progress. They thought the golden age was in the past.
  • Admitting our ignorance, combined with new power from scientific discoveries, led people to suspect that real progress was possible after all.
  • Throughout history, societies have suffered from two kinds of poverty: social poverty, which withholds from some people the opportunities available to others; and biological poverty, which puts the very lives of individuals at risk due to lack of food and shelter
  • Until recently, many cultures have viewed poverty as an inescapable part of an imperfect world. In many countries around the world today, biological poverty is a thing of the past. Individuals are protected from personal misfortune by insurance, state-sponsored social security and NGOs.

The Gilgamesh Project

  • For men of science, death is not an inevitable destiny, but merely a technical problem.
  • Our best minds are not wasting their time trying to give meaning to death. Instead, they are busy investigating the physiological, hormonal and genetic systems responsible for disease and old age.
  • Pills, injections and sophisticated operations save us from a spate of illnesses and injuries that once dealt an inescapable death sentence.
  • A few serious scholars suggest that by 2050, some humans will become a-mortal.

The Sugar Daddy of Science

  • Science is a very expensive affair.
  • Most scientific studies are funded because somebody believes they can help attain some political, economic or religious goal.
  • Science is unable to set its own priorities. It is also incapable of determining what to do with its discoveries.
  • Scientific research can flourish only in alliance with some religion or ideology. The ideology justifies the costs of the research. In exchange, the ideology influences the scientific agenda and determines what to do with the discoveries.
  • The feedback loop between science, empire and capital has arguably been history’s chief engine for the past 500 years.

15) The Marriage of Science and Empire

  • The Scientific Revolution and modern imperialism were inseparable.
  • Astronomers predicted that the next Venus transits would occur in 1761 and 1769. So expeditions were sent from Europe to the four corners of the world in order to observe the transits from as many distant points as possible. In 1761 scientists observed the transit from Siberia, North America, Madagascar and South Africa.

Why Europe?

  • Between 1500 and 1750, western Europe gained momentum and became master of the “Outer World,” meaning the two American continents and the oceans. But only because the great powers of Asia showed little interest in them.
  • Why did Europeans discover and conquer the Americas? Why not the Chinese or those from India or the Middle East who possessed just as much knowledge and technology as the Europeans? The European ideology to explore the world was the primary difference.
  • The global center of power shifted to Europe only between 1750 and 1850 when Europeans humiliated the Asian powers in a series of wars and conquered large parts of Asia.
  • Today all humans are, to a much greater extent than they usually want to admit, European in dress, thought and taste.
  • European influence and dominance from 1850 onward was due to a large extent on their military-industrial-scientific complex and technological wizardry.
  • The Chinese and Persians did not lack technological inventions such as steam engines (which could be freely copied or bought). They lacked the values, myths, judicial apparatus and sociopolitical structures that took centuries to form and mature in the West and which could not be copied and internalized rapidly.
  • Europeans were used to thinking and behaving in a scientific and capitalist way even before they enjoyed any significant technological advantages.

The Mentality of Conquest

  • Modern science flourished in and thanks to European empires.
  • The plant-seeking botanist and the colony-seeking naval officer shared a similar mindset that began by admitting ignorance and compelled them to go out and make new discoveries.

Empty Maps

  • During the fifteenth and sixteenth centuries, Europeans began to draw world maps with lots of empty spaces. The empty maps were a psychological and ideological breakthrough, a clear admission that Europeans were ignorant of large parts of the world.
  • In contrast to Europeans, Afro-Asian cultures filled the unknown areas on a map with imaginary monsters and wonders. These maps had no empty spaces. They gave the impression of a familiarity with the entire world.
  • Europe did not enjoy an outstanding technological edge to the rest of the world. What made Europeans exceptional was their unparalleled and insatiable ambition to explore and conquer.
  • The discovery of America was the foundational event of the Scientific Revolution. It not only taught Europeans to favour present observations over past traditions, but the desire to conquer America also obliged Europeans to search for new knowledge at breakneck speed.

Rare Spiders and Forgotten Scripts

  • Linguistics received enthusiastic imperial support. The European empires believed that in order to govern effectively they must know the languages and cultures of their subjects.
  • Without such knowledge, it is unlikely that a ridiculously small number of Britons could have succeeded in governing, oppressing and exploiting millions of subjects.
  • Modern Europeans came to believe that acquiring new knowledge was always good.
  • Imperialists claimed that their empires were not vast enterprises of exploitation but rather altruistic projects conducted for the sake of the non-European races.
  • Due to their close cooperation with science, these empires wielded so much power and changed the world to such an extent that perhaps they cannot be simply labelled as good or evil. They created the world as we know it, including the ideologies we use in order to judge them.

16) The Capitalist Creed

  • To understand modern economic history, you really need to understand a single word: Growth.
  • For most of human history, per capita production remained the same. Since the launch of capitalism, however, per capita production has skyrocketed.
  • Credit enables us to build the present at the expense of the future. It is founded on the assumption that our future resources are sure to be far more abundant than our present resources.

A Growing Pie

  • Over the last 500 years the idea of progress convinced people to put more and more trust in the future. This trust created credit; credit brought real economic growth; and growth strengthened the trust in the futures and opened the way for even more credit.
  • Credit allows you to borrow money now because we collectively trust that the future will be better than the present.
  • In the new capitalist creed, the first and most sacred commandment is: “The profits of production must be reinvested in increasing production.”
  • The “religion” of capitalism says economic growth is the supreme because justice, freedom, and happiness requires economic growth.
  • Capitalism has gradually become more than just an economic doctrine. It now encompasses an ethic—a set of teachings about how people should behave, educate their children and even think.
  • Ask a capitalist how to bring justice and political freedom to a place like Zimbabwe or Afghanistan, and you are likely to get a lecture on how economic affluence and a thriving middle class are essential for stable democratic institutions.
  • Capitalism’s belief in perpetual economic growth flies in the face of almost everything we know about the universe.
  • Banks and governments print, but ultimately, it is the scientists who foot the bill.

Adam Smith’s claim that the selfish human urge to increase private profits is the basis for collective wealth is one of the most revolutionary ideas in human history—revolutionary not just from an economic perspective, but even more so from a moral and political perspective. What Smith says is, in fact, that greed is good, and that by becoming richer I benefit everybody, not just myself. Egoism is altruism.

Columbus Searches for an Investor

  • Napoleon made fun of the British, calling them a nation of shopkeepers. Yet theses shopkeepers defeated Napoleon himself, and their empire was the largest the world has ever seen.
  • In order to control trade on the important Hudson River, The Dutch West India Company (WIC) built a settlement called New Amsterdam on an island at the river’s mouth. The colony was threatened by Indians and repeatedly attacked by the British, who eventually captured it in 1664. The British changed its name to New York. The remains of the wall built by WIC to defend its colony against Indians and British are today paved over by the world’s most famous street – Wall Street.

In the Name of Capital

  • The amount of credit in an economy is determined not only by purely economic factors, but also by political events such as regime changes or more ambitious foreign policies.

The Cult of the Free Market

  • At the end of the Middle Ages, slavery was almost unknown in Christian Europe. During the early modern period, the rise of European capitalism went hand in hand with the rise of the Atlantic slave trade. Unrestrained market forces, rather than tyrannical kings or racist ideologues, were responsible for this calamity.
  • Free-market capitalism cannot ensure that profits are gained in a fair way (e.g. Opium Trade of British with China), or distributed in a fair manner.
  • When growth becomes a supreme good, unrestricted by any other ethical considerations, it can easily lead to catastrophe. Capitalism has killed millions out of cold indifference coupled with greed (e.g. Atlantic Slave Trade)
  • After 1908, and especially after 1945, capitalist greed was somewhat reined in, not least due to the fear of Communism. Yet inequities are still rampant.

17) The Wheels of Industry

  • Counterintuitively, while humankind’s use of energy and raw materials has mushroomed in the last few centuries, the amounts available for our exploitation have actually increased.

The Secret in the Kitchen

  • The steam engine was the first invention to convert heat into movement.
  • The internal combustion engine revolutionized human transportation and turned petroleum into liquid political power.

An Ocean of Energy

  • Every few decades we discover a new energy source, so that the sum total of energy at our disposal just keeps growing.
  • All human activities and industries put together consume about 500 exajoules annually, equivalent to the amount of energy earth receives from the sun in just ninety minutes.

Life on the Conveyor Belt

  • Today in the United States, only 2% of the population makes a living from agriculture, yet this 2% produces enough not only to feed the entire US population, but also to export surpluses to the rest of the world.
  • Without the industrialization of agriculture the urban Industrial Revolution could never have taken place—there would not have been enough hands and brains to staff factories and offices.

The Age of Shopping

  • The modern capitalist economy must constantly increase production in order to survive. Who is supposed to buy all this stuff?
  • Consumerism sees the consumption of ever more products and services as a positive thing.
  • Consumerism has worked very hard, with the help of popular psychology to convince people that indulgence is good for you, whereas frugality is self-oppression.
  • Each year the US population spends more money on diets than the amount needed to feed all the hungry people in the rest of the world.
  • The rich take great care managing their assets and investments, while the less well heeled go into debt buying cars and televisions they don’t really need.
  • The rich invest while the poor buy.

18) A Permanent Revolution

  • The future is unlikely to yield a lack of resources, but very likely to destroy what remains of the natural habitat and drive most other species to extinction.
  • Destruction of the ecosystem may increase the frequency of human-induced natural disasters.

Modern Time

  • The Industrial Revolution turned the timetable and the assembly line into a template for almost all human activities. Example: Schools, Hospitals adopted precise timetables.
  • Public transportation solidified our dependence on strict time-keeping.
  • Cheap but precise portable clocks became ubiquitous.
  • Today, a single affluent family generally has more timepieces at home than an entire medieval country.
  • The role of family and the local community has been replaced by the state and the market.

The Collapse of the Family and the Community

  • A person who lost her family and community around 1750 was as good as dead. She had no job, no education and no support in times of sickness and distress.
  • Over time, states and markets used their growing power to weaken the traditional bonds of family and community. Policemen were sent to stop family vendettas and replace them with court decisions. The market sent its hawkers to wipe out long-standing local traditions and replace them with ever-changing commercial fashions.
  • “Be your own individual.” You are no longer dependent on your family or your community. We, the state and the market, will take care of you instead.
  • But the liberation of the individual comes at a cost. Many of us now bewail the loss of strong families and communities and feel alienated and threatened by the power of the impersonal state and market wield over our lives.

Until not long ago, the suggestion that the state ought to prevent parents from beating or humiliating their children would have been rejected out of hand as ludicrous and unworkable. In most societies parental authority was sacred. Respect of and obedience to one’s parents were among the most hallowed values, and parents could do almost anything they wanted, including killing newborn babies, selling children into slavery and marrying off daughters to men more than twice their age. Today, parental authority is in full retreat. Youngsters are increasingly excused from obeying their elders, whereas parents are blamed for anything that goes wrong in the life of their child.

Imagined Communities

  • The consumer tribe is the imagined community of the market because it is impossible for all customers in a market to know one another the way villagers knew one another in the past.
  • In recent decades, national communities have been increasingly eclipsed by tribes of customers who do not know one another intimately but share the same consumption habits and interests.

Perpetuum Mobile

  • Over the last two centuries, the pace of change became so quick that the social order acquired a dynamic and malleable nature. It now exists in a state of permanent flux.
  • Today, even a thirty-year-old can honestly tell disbelieving teenagers, “When I was young, the world was completely different.”
  • The only characteristic of modern society of which we can be certain is the incessant change.
  • The seven decades that have elapsed since the end of WWII have been the most peaceful era in human history—and by a wide margin. This is surprising because these very same decades experienced more economic, social and political change than any previous era.

Peace in Our Time

  • Real peace is not the mere absence of war. Real peace is the implausibility of war.
  • Most people don’t appreciate just how peaceful an era we live in. We easily forget how much more violent the world used to be.
  • Today humankind has broken the law of the jungle. There is at last real peace, and not just absence of war.
  • In the year following the 9/11 attacks, despite all the talk of terrorism and war, the average person was more likely to kill himself than to be killed by a terrorist, a soldier or a drug dealer.
  • The decline of violence is due largely to the rise of the state. Throughout history, most violence resulted from local feuds between families and communities.

Pax Atomica

  • The price of war has gone up dramatically.
  • The Nobel Peace Prize to end all peace prizes should have been given to Robert Oppenheimer and his fellow architects of the atomic bomb.
  • Nuclear weapons have turned war between superpowers into collective suicide, and made it impossible to seek world domination by force of arms.
  • The profits of war have declined.
  • Wealth today is less in material things and more concentrated in human capital and organizational know-how. Both are difficult to conquer by military force.
  • What would happen if the Chinese were to mount an armed invasion of California? They would gain little. There are no silicon mines in Silicon Valley. The wealth resides in the minds of Google engineers and Hollywood script doctors, directors and special-effects wizards, who would be on the first plane to Bangalore or Mumbai long before the Chinese tanks rolled into Sunset Boulevard.
  • It is not coincidental that the few full-scale international wars that still take place in the world, such as the Iraqi invasion of Kuwait, occur in places where wealth is old-fashioned material wealth. The Kuwaiti sheikhs could flee abroad, but the oil fields stayed put and were occupied.
  • Peace has become more lucrative than ever.
  • For the first time in history the world is dominated by a peace-loving elite—politicians, business people, intellectuals and artists who genuinely see war as both evil and avoidable.
  • The tightening web of international connections erodes the independence of most countries lessening the chance that any one of them might single-handedly let slip the dogs of war.

19) And They Lived Happily Ever After

  • Historians avoid raising the question: Does “progress” make people happier?
  • New aptitudes, behaviors and skills do not necessarily make for a better life.
  • Some argue an inverse correlation between human capabilities and happiness. Power corrupts.
  • When judging modernity, it is all too tempting to take the viewpoint of a twenty-first-century middle-class Westerner. We must not forget the viewpoints of a nineteenth-century Welsh coal miner, Chinese opium addict or Tasmanian Aborigine. Truganini is no less important than Homer Simpson.
  • We can’t judge this era too quickly. It is too early to know whether this represents a fundamental shift in the currents of history or an ephemeral eddy of good fortune. Even the brief golden age of the last half-century may turn out to have sown the seeds of future catastrophe.
  • We can congratulate ourselves on the unprecedented accomplishments of modern Sapiens only if we completely ignore the fate of all other animals.

Counting Happiness

  • Social, ethical and spiritual factors have as great an impact on our happiness as material conditions.
  • Perhaps people in modern affluent societies suffer greatly from alienation and meaninglessness despite their prosperity. And perhaps our less well-to-do ancestors found much contentment in community, religion and a bond with nature.
  • Money brings happiness only up to a point, and beyond that it has little significance.
  • Illness is only a source of long-term distress if the condition continues to deteriorate or causes ongoing pain.
  • Family and community seem to have more impact on our happiness than money and health.
  • Improvement in material conditions over the past two centuries may have been offset by the collapse of family and community. If so, the average person may well be no happier today than in 1800.
  • Happiness does not really depend on objective conditions of either wealth, health or even community. Rather, it depends on the correlation between objective conditions and subjective expectations.
  • Happiness = Expectations – Reality
  • This is why winning the lottery has, over time, the same impact on people’s happiness as a debilitating car accident. When things improve, expectations balloon, and consequently even dramatic improvements in objective conditions can leave us dissatisfied.
  • Suppose science comes up with cures for all diseases, effective anti-ageing therapies and regenerative treatments that keep people indefinitely young. In all likelihood, the immediate result will be an unprecedented epidemic of anger and anxiety.
  • If happiness is determined by expectations, then two pillars of our society – mass media and the advertising industry – may unwittingly be depleting the globe’s reservoirs of contentment.

We moderns have an arsenal of tranquilizers and painkillers at our disposal, but our expectations of ease and pleasure , and our intolerance of inconvenience and discomfort, have increased to such an extent that we may well suffer from pain more than our ancestors ever did.

Chemical Happiness

  • People are made happy by pleasant sensations in their bodies.
  • We are predisposed to maintain a certain threshold of happiness. Some people are naturally more cheerful than others.
  • If we accept the biological approach to happiness, then history turns out to be of minor importance, since most historical events have had no impact on our biochemistry.
  • When we finally realize that the keys to happiness are in the hands of our biochemical system, we can stop wasting our time on politics and social reforms, putsches and ideologies and focus instead on the only thing that can make us truly happy: manipulating our biochemistry.

The Meaning of Life

  • If happiness is based on pleasurable feelings, then increasing our happiness is a matter of increases biochemical release. If happiness is based on meaning, then increasing our happiness is a matter of deluding ourselves about the meaning of our lives.
  • One uncommonly cited benefit of religion: belief in the afterlife gives meaning to your life in the present.
  • When counting moments of joy and moments of drudgery, bringing up a child turns out to be a rather unpleasant affair. It consists largely of changing nappies, washing dishes and dealing with temper tantrums, which nobody likes to do. Yet most parents declare that their children are their chief source of happiness. Does it mean that people don’t really know what’s good for them?
  • According to a study by Daniel Kahneman, happiness is not the surplus of pleasant over unpleasant moments. Rather, happiness consists in seeing one’s life in its entirety as meaningful and worthwhile.
  • As long as my personal narrative is in line with the narratives of the people around me, I can convince myself that my life is meaningful, and find happiness in that conviction.
  • Nietzsche: “He who has a why to live can bear almost any how.”
  • Buddhism shares many viewpoints on happiness with science. Most notably, that happiness results from processes within the body and not from the outside world.
  • Buddhist philosophy of happiness centers around the idea that you are not the events that happen to you, but you are also not the feelings you have. You are not your feelings. They are just feelings. Thus, if you understand this, you can release the needs to keep chasing the need to feel happy or to not feel angry or to not feel sad
  • Perhaps happiness is synchronizing one’s personal delusions of meaning with the prevailing collective delusions.

20) The End of Homo Sapiens

  • The replacement of natural selection by intelligent design could happen in any of three ways: through biological engineering, cyborg engineering, or the engineering of inorganic life.
  • Genetic engineering is allowing humans to break the laws of natural selection.
  • Geneticists hope to revive extinct animals.
  • Prosthetics have been engineered to be controlled by the electrical signals from the brain.
  • The next stage of history will include not only technological and organizational transformations, but also fundamental transformations in human consciousness and identity.
  • Sapiens are the new gods of ‘Intelligent Design’ – they are Homo Deus. Their future is not human, it is transhuman as they transition into something new. If they do not destroy themselves first.
  • In the past 1000 years, humans have evolved to take over the world and are on the verge of overcoming natural selection and becoming gods. Yet, we still seem unhappy in many ways and we are unsure of what we want. Is there anything more dangerous than dissatisfied and irresponsible gods who don’t know what they want?
  • The real question facing us is not ‘What do we want to become?’, but ‘What do we want to want?’ Those who are not spooked by this question probably haven’t given it enough thought.

P.S.: While the book Sapiens ends with The Scientific Revolution. There is a sequel to Sapiens: Homo Deus which is a History of Tomorrow.

This is the end of the four-part series of Sapiens Book Summary. If you liked this one and would like to read more of Yuval Noah Harari, please check his other books below:

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