Sapiens, A Brief History of Humankind by Yuval Noah Harari

Chapter 1 An animal of no significance.
History is marked by three revolutions. The Cognitive Revolution of 70 thousand years ago, the Agricultural Revolution of 12 thousand years ago and the Scientific Revolution 500 years ago. Six million years ago the offspring of a chimpanzee diverged. One became the ancestor of modern chimpanzees, the other was our ancestor. Humans produced the first tools about 2.5 million years ago. Homo Sapiens appeared about 150 thousand years ago. Humans did not jump to the top of the food chain until 100 thousand years ago. It is thought that the use of fire for cooking allowed our intestines to become shorter, decreasing their energy consumption and so opened the way to the jumbo brains of Neanderthals and Sapiens. Fire opened up the first significant gulf between humans and the other animals. 

Chapter 2 How we evolved
There were six human species about 100,000 years ago. Then around 70,000 years ago, one species - that's us - drove the others to extinction. Scholars believe that at this time or somewhat later, Homo Sapiens underwent a Cognitive Revolution. One theory holds that a genetic mutation changed the brains of Sapiens, allowing them to think in unprecedented ways and to use an altogether new kind of language. As Harari points out, a parrot could say anything that Albert Einstein could say. Whatever advantage Einstein had, it wasn't vocal. 

The language of Homo Sapiens differs from the communication systems of the other animals by being amazingly supple. One theory holds that language evolved mainly to convey information about humans, ie it evolved to allow gossip. We are primarily a social animal and social cooperation is our key to survival and reproduction. Even today, the vast majority of human communication - whether emails, phone calls or newspaper articles - is gossip. 

Harari stakes the fascinating claim that the most powerful feature of our language is not its ability to convey detailed information about lions or people. Rather, he thinks it is the capability to transmit information about non-existent things. 

It is believed that legends, myths and religions first appeared at the time of the Cognitive Revolution. You could never convince a monkey to give you a banana by promising him limitless bananas after death in a monkey heaven. Wouldn't a human who spends hours praying to non-existent gods be wasting time, which would be better spent foraging, fighting or fornicating? Harari answers that fiction allows us to imagine things collectively, such as the Biblical creation story, the aboriginal Dreamtime or the nationalist myths of modern states. These myths give Sapiens the unprecedented ability to cooperate flexibly in unlimited numbers. Ants and chimps can cooperate, but not as flexibly nor in such large numbers. Sapiens can cooperate in extremely flexible ways with countless numbers of strangers. That's why Sapiens rule the world, whereas ants eat our leftovers and chimps are locked up in zoos and research laboratories. 

In the wake of the Cognitive Revolution, gossip helped Sapiens form larger and more stable bands. But even gossip has its limits. There is a critical threshold, around 150, up to which number social relationships can be maintained by means of intimate acquaintance. Above 150, personal acquaintance cannot maintain social cohesion. Harari thinks the reason why Sapiens was able to create cities and empires containing millions of people is fiction. Large numbers of strangers can cooperate successfully by believing in common myths. Any large-scale human cooperation, whether a modern state, a church, a city or a tribe, is rooted in common myths that exist only in peoples' collective imaginations. There are no laws, no gods, no nations, no money, and no human rights outside the common imaginations of human beings. For instance, money would have zero value if no-one believed in it. The same goes for a nation state such as Australia. If no-one believed in it then it would cease to exist.

An example of a fiction is Peugeot. It is what lawyers term a 'legal fiction'. It is not a physical object, nor is it constituted by its employees, factories or shareholders. It exists as a legal entity. Limited liability companies are legally independent of the people who set them up, invest in them, manage them or work for them. Such companies are the main players in the economic arena, and we have grown so used to them that we forget they exist only in our imagination. 

Unlike lying, an imagined reality is something that everyone believes in, and as long as this communal belief persists the imagined reality exerts force in the world. It allows strangers to cooperate and work towards common goals. 

Ever since the Cognitive Revolution, Sapiens has been living in a dual reality. On the one hand, the objective reality of rivers, trees and lions; and on the other hand, the imagined reality of gods, nations and corporations. The imagined reality became so powerful that today the very survival of rivers, trees and lions depends on the grace of imagined entities such as the United States and Google.

Chapter 3
Our psychological makeup owes its origins to the hunter-gatherer lifestyle that was our lot for the vast majority of our existence as a species. This explains why modern people gorge themselves on high-calorie food that does their bodies little good. There is a consequent plague of obesity. 

Fishing villages were probably the first human settlements and date back around 45 thousand years ago, long before the Agricultural Revolution. 

We live in an age of specialisation, where experts know much about a narrow field. We rely blindly on the expertise of others. The human collective knows far more today than did the ancient bands. But at the individual level, ancient foragers were the most knowledgeable and skilful people in history. Survival required superb mental abilities from everyone. When agriculture and industry came along, people could increasingly rely on the skills of others for survival, and new "niches for imbeciles" were opened up. You could survive and pass on your sub-standard genes by working as a water carrier or assembly line worker. 

On the whole, foragers seem to have enjoyed a more comfortable and rewarding lifestyle than most of the peasants, shepherds, labourers and office clerks who followed. While people in today's affluent societies work a 40 or 45 hour week, and people in poor countries work 60 hours or more, foragers in one of the most inhospitable habitats, such as the Kalahari desert, need just 40 hours per week to secure their food. Foragers in more hospitable areas probably worked less than this. Foraging provided ideal nutrition. Fossilised skeletons show that foragers suffered less from starvation or malnutrition than their peasant descendants. Children who survived the first years had a good chance of reaching 60. The foragers' diet was much more varied than those of peasants, who relied mostly on a single crop, such as wheat or rice. By not being dependent on any single food, they were less likely to suffer if a particular source failed. Agricultural societies are ravaged by famine when their main crop suffers a failure, such as due to drought or flood. 

Ancient foragers suffered far less from infectious diseases. Most of the infectious diseases that have plagued agricultural and industrial societies, such as smallpox, measles and tuberculosis, originated in domesticated animals and were transferred to humans only after the Agricultural Revolution. Moreover, most people in agricultural and industrial societies lived in dense, unhygienic permanent settlements - ideal hotbeds for disease. Foragers roamed in small bands that could not sustain epidemics. 

Chapter 4
Due to isolation, our planet was divided into several distinct ecosystems, each made up of a unique assembly of animals and plants. Following the Cognitive Revolution, Sapiens acquired the technology and the organisational skills to break out of Afro-Asia and settle the Outer World. Their first achievement was the colonisation of Australia 45,000 years ago. This required ocean-worthy vessels. Sapiens climbed to the top rung in the food chain and became the deadliest species ever in the 4-billion-year history of life on earth. The settlers of Australia transformed the Australian ecosystem beyond recognition. 

At the time, Australia had weird creatures such as a 200 kg kangaroo, a large marsupial lion, giant koala, giant flightless birds and a two-ton wombat (the diprotodon). Within a few thousand years, virtually all these giants vanished. Of the 24 species weighing 50 kg or more, all but one became extinct. Sapiens was the cause. The megafauna had no knowledge of humans and did not have time to learn to fear us. In addition, Sapiens deliberately burned large tracts of impassable thickets and dense forests, to create open grasslands, which better suited their needs. Eucalyptus trees were rare in Australia 45,000 years ago, but the arrival of Sapiens was a golden age for eucalyptus, as they survive well after fire. Other trees disappeared.

Sapiens crossed from Siberia to Alaska in 14,000 BC and by 10,000 BC had occupied both North and South America, right down to Tierra del Fuego. Within 2,000 years of Sapiens' arrival, most of the megafauna, such as 8-ton ground sloths, were gone. In conclusion, the first wave of Sapiens colonisation was one of the biggest and swiftest ecological disasters to befall the animal kingdom. 

Chapter 5 History's biggest fraud
The transition to agriculture, after 2.5 million years of gathering plants and hunting animals, began in 9500-8500 BC. Our species began to spend all their time and effort manipulating the lives of a few animal and plant species. Even today, more than 90% of the calories that feed us come from wheat, rice, maize, potatoes, millet and barley - plants that our ancestors domesticated between 9500 and 3500 BC. No noteworthy plant or animal has been domesticated in the last 2,000 years. Agriculture arose independently in the Middle East, Central America, South America, North America, New Guinea and China. The Agricultural Revolution did not happen in Australia or South Africa because there were no suitable plants to domesticate. By the first century AD the vast majority of people in most parts of the world were agriculturalists. For agriculture to develop in a region it required plants that could be domesticated. Of the thousands of species that our ancestors hunted and gathered, only a few were suitable candidates for farming and herding. 

The Agricultural Revolution left farmers with lives generally more difficult and less satisfying than those of foragers. Hunter-gatherers spent their time in more stimulating and varied ways and were less in danger of starvation and disease. The Agricultural Revolution certainly enlarged the sum total of food for humans, but the extra food did not translate into a better diet or more leisure. Rather, it translated into population explosions and pampered elites. It created social and political inequality. The Agricultural Revolution was history's biggest fraud. Humans were doing little from dawn to dusk other than taking care of wheat plants. Studies of ancient skeletons indicate that the transition to agriculture brought about a plethora of ailments, such as slipped discs, arthritis and hernias. Wheat also forced people to settle permanently near the wheat fields.

The life of the peasant is less secure than that of a hunter-gatherer. Hunter-gatherers relied on dozens of species to survive, unlike the farmer, who was dependent on a single crop. If rains failed, locusts arrived or a fungus infected the crop then peasants died in their thousands or millions.  

Nor did security against violence increase. Many studies indicate that in simple agricultural societies with no political frameworks beyond village and tribe, human violence was responsible for 25% of male deaths. It took thousands of years to build huge political structures that brought violence under control. For the average person the disadvantages probably outweighed the advantages. Wheat offered nothing for people as individuals. However, it allowed Sapiens to multiply exponentially. The essence of The Agricultural Revolution was the ability to keep more people alive under worse conditions. Nobody agreed to this deal. It was a trap.

Looking back, we regard the Agricultural Revolution as a wonderful improvement because it laid the foundation for all that we enjoy today. However, at the time it was a trap. The change from hunting and gathering to farming proceeded by stages. The change from eating and inadvertently spreading wild grains to cultivating them was gradual. People first settled for four weeks during harvest, then for longer and longer periods until settlements became permanent. With time, the burden of growing wheat became heavier. Paradoxically, a series of improvements to farming, intended to make life easier, added up to a millstone around the necks of farmers. 

Why did people miscalculate the effects of the Agricultural Revolution? For the same reason that people throughout history have miscalculated: they were unable to fathom the full consequences of their decisions. They worked harder to grow more wheat. This part worked fine. What they did not foresee was that the number of children would increase, so that the extra wheat would have to be shared among more mouths. Nor did the early farmers understand that feeding the children with more porridge and less milk would weaken their immune systems, and that permanent settlements would be hotbeds for infectious diseases. They did not foresee that by making themselves dependent on a single source of food that they were exposing themselves even more to the depredations of drought. To sum up, humanity's search for an easier life released immense forces that transformed the world in ways nobody envisioned or wanted. 

Why didn't humans abandon farming when the plan backfired? Partly because it took generations for the small changes to accumulate and transform society, by which time nobody remembered that they had lived differently. And partly because population growth burnt our boats. There was no going back. The trap snapped shut. The pursuit of an easier life resulted in much hardship, and not for the last time. Harari compares this to young people who vow to work hard and then pursue their real interests, but who get caught in the materialistic trap, as well as in raising a family. One of the iron laws of history is that luxuries tend to become necessities and to spawn new obligations. Once people get used to a new luxury they take it for granted. Then they can't live without it, eg air-conditioning in cars. Harari cites the change from writing letters to emails. Previously, it took a fair amount of effort to write a letter, address and stamp it and take it to a mailbox. It might take weeks to receive a reply. Email allows effortless and nearly instant communication across the globe. Harari asks rhetorically whether this has made life more relaxed. We thought we were saving time; instead we revved up the treadmill of life.

The domestication of animals gave rise to cruelty on a mass scale. Cattle increased greatly in numbers due to breeding by humans. However, their numerical success was at the cost of subjugation to a way of life completely alien to their urges and desires. It's reasonable to assume, that bulls prefer to spend their days wandering over prairies in the company of other bulls and cows, rather than pulling carts and ploughshares under the yoke of a whip-wielding ape. For the vast majority of domesticated animals the Agricultural Revolution was a terrible catastrophe.

Of course, the Agricultural Revolution had other effects, such as living in houses, acquiring possessions, the division of labour, plus the thing we like to call civilisation.

Roberto, who lived for a time with hunter-gatherers in Borneo, does not agree with the slanders heaped by Harari on the Agricultural Revolution. He thinks that Jared Diamond and Harari are guilty of romanticising the hunter-gatherer life. Although they had more leisure than do farmers they did not use it profitably. They mainly sat around talking about magic or gossiped. He also said that one of the last hunter-gatherer groups of aborigines discovered in Australia were living a terrible existence. He said the hunter-gatherer lifestyle is very restricted with minimal cultural development.

Chapter 6 The imagined order that sustains society
An imagined order is always in danger of collapse, because it depends upon myths, and myths vanish once people stop believing in them. In order to safeguard an imagined order, continuous and strenuous efforts are imperative. Some of these efforts take the form of violence and coercion. Yet an imagined order cannot be sustained by violence alone. It requires some true believers as well. In particular, large segments of the security forces and the elite must believe in it. Christianity would not have lasted 2,000 years if the majority of bishops and priests did not believe in Christ. The modern economic system would not last a single day if the majority of bankers and investors did not believe in capitalism.

How do you cause people to believe in an imagined order such as Christianity, democracy or capitalism? First, you never admit that the order is imagined. You insist that the order sustaining society is an objective reality created by the great gods or by the laws of nature. The order is maintained by education and conditioning, which start at birth. What is more, every person's desires are shaped by the dominant myths. Our personal desires become the imagined order's most important defences. The most cherished desires of Westerners are shaped by romantic, nationalist, capitalist and humanist myths. We are told to follow our heart, but the heart is a double agent that takes its instructions from the dominant myths of the day.

Romanticism tells us that in order to make the most of our human potential we must have as many different experiences as we can. Hence the appeal of travel. Consumerism tells us that in order to be happy we must consume as many products and services as possible. Every commercial is a little legend about how consuming some product or service will make life better. Romanticism meshes perfectly with consumerism, resulting in the infinite market of experiences on which the modern tourism industry is based. 

As in Ancient Egypt, most people in most cultures dedicate their lives to building pyramids. Whether these take the form of a suburban cottage or a penthouse with sweeping views, few question the myths that cause us to desire the pyramid in the first place. 

The imagined order is not simply subjective, it is inter-subjective. It exists within the communication network linking the subjective consciousness of many individuals. Many of history's most important drivers are inter-subjective: law, money, gods, nations. 

Since an imagined order exists in the shared imaginations of millions, to change an imagined order we must change the consciousness of millions or even billions of people. A change of such magnitude can only be accomplished with the help of a complex organisation, such as a political party, an ideological movement or a religious cult. However, in order to establish such complex organisations, it's necessary to convince many strangers to cooperate with one another. This will only happen if these strangers believe in some shared myths. To change an existing imagined order we must first believe in an alternative imagined order. Yet there is no way out of of living in an imagined order. When we break down our prison walls and run towards freedom, we are in fact running into the more spacious exercise yard of a larger prison.

Chapter 7 Writing
The story so far is that humanity underwent the cognitive and agricultural revolutions. The third major revolution was the invention of writing.

The human brain cannot store all the important facts needed to run an empire. When human communities grew large, numbers became important. To run an empire you need to maintain accounts, lots of them. The authorities need to know who owns a plot of land, what taxes are owing and many other facts, mostly relating to inventory and finances. 

Between 3500 and 3000 BC some people in Sumer invented the first system for storing and processing information outside their brains, one that was custom-built to handle large amounts of arithmetical data. The invention of a script gave humanity the capability to create cities, kingdoms and empires. One of the earliest names known to us is "Kushim", who was, naturally, an accountant. One of the earliest extant texts states that "29,086 measures of barley were received over the course of 37 months, signed Kushim".

The Sumerian system had signs for numbers and other signs that represented people, animals, land etc. The script was used solely for maintaining accounts. At this early stage there was no writing of poetry, legends, laws or historical events. All this remained oral. Harari calls the earliest writing a partial script, as it was only suitable for recording quantities, payments, debts and ownership of properties.

A full script, ie a system of writing that can represent spoken language more or less completely, was developed before 2500 BC in Sumer. The Egyptians developed their hieroglyphs at about the same time. Henceforth, kings issued decrees, priests wrote oracles, people even wrote private letters. Some began to write poetry, history books, romances, dramas, prophecies and cookbooks. However, the principal function of writing was still to record arithmetical data. Bureaucracies were born together with partial script, and the two remain inexorably linked to this day, like Siamese twins.

However, having all the facts written down is not enough. You need to be able to retrieve data, which is not easy if you have a room-full of clay tablets. The creation of systems of retrieval was a greater challenge than creating writing itself. One needs catalogues and indexes. Sumer, Egypt and the Inca Empire developed good techniques for archiving, cataloguing and retrieving written records. (NB The Incas did not have writing, but only a system of accounting.) They also invested in schools for scribes, clerks, librarians and, of course, accountants.

According to Harari, the most important impact of script on human history is that it has gradually changed the way humans think and view the world. Free association and holistic thoughts have given way to compartmentalisation and bureaucracy. Modern mathematical notation, though a partial script, has become the world's dominant language. More recently, mathematical script has given rise to an even more revolutionary writing system, a computerised script consisting of just 0 and 1.

Chapter 8
Human history since the Agricultural Revolution boils down to a single question: how did humans organise themselves in mass-cooperation networks, when they lacked the biological instincts necessary to sustain such networks? They did so by creating invented orders and devising scripts.

The imagined orders sustaining these networks arranged people in a hierarchy, privileging some people while discriminating against others. It is an iron rule of history that every imagined order disavows its fictional origins and claims to be natural and inevitable. 

Chapter 9 The Arrow of History
Every human-made imagined order is packed with internal contradictions. Cultures are constantly trying to reconcile these contradictions, and this process fuels change. An example from the Middle Ages was the contradictions between chivalry and Christianity, both of which the nobility believed in. One attempt to reconcile the two gave rise to the Crusades, where knights could demonstrate their military prowess and their devotion at one stroke. A modern example are the twin values of social equality and individual freedom. These two values contradict each other. Equality can only be assured by curtailing the freedom of those who are better off. The entire political history of the world since 1789 can be seen as a series of attempts to reconcile this contradiction. In 19th century England the priority was individual freedom, with the consequence that the lower classes lived in misery. At the other extreme, in communist Russia the egalitarian ideal produced a brutal tyranny that tried to control every aspect of life. 

In contemporary USA, Democrats want a more equitable society, at the cost of raising taxes, whereas Republicans want to maximise individual freedom, even if it means widening the gap between the rich and the poor. Medieval society did not manage to reconcile chivalry with Christianity. Modern societies have not managed to reconcile freedom with equality. Such contradictions are an inseparable part of every human culture. They are the engines of cultural development, responsible for the creativity and dynamism of our species. Discord in our thoughts, ideals and values compels us to think, re-evaluate and criticise. A human being who belongs to any particular culture must hold contradictory beliefs and be riven by incompatible values. This is called cognitive dissonance. Rather than being a failure of the human psyche, it is a vital asset. Had people been unable to hold contradictory beliefs and values, it would probably have been impossible to establish and maintain any human culture. 

Harari argues that human history has a direction - towards unity. Around 10,000 BC there were many thousands of separate worlds, ie cultures that were totally isolated from each other. By AD 1450, just prior to the European age of exploration, there were still many small worlds separate from each other, such as Tasmania. However, close to 90% of humans lived in the African-Asian-European world, which was connected by significant cultural, economic and political ties. Over the next 300 years, the Afro-Asian-European giant swallowed up all the other worlds. The Spanish conquered the Aztec Empire in 1521 and the Inca Empire in 1532. Today, almost all humans share the same geopolitical system, ie sovereign states, the same economic system, ie capitalism, and the same scientific system. Today, when Iran and the US rattle swords at one another, they both speak the same language of nation states, capitalist economies, international rights and nuclear physics. Harari thinks there is no such thing as an "authentic" culture any more. Over the last few centuries, all cultures were changed almost beyond recognition by a flood of global influences.

We evolved to think of people as 'us' and 'them'. 'Us' was the group immediately around you, and 'them' was everyone else. However, after the Cognitive Revolution, people began to cooperate increasingly with strangers, whom they saw as brothers or friends. The first millennium BC witnessed the appearance of three potentially universal orders, according to which the entire human race was a single entity, governed by the same laws. The first universal order to appear was economic - the monetary order. The second universal order was political - the imperial order. The third universal order was religious - the order of universal religions, such as Christianity, Buddhism and Islam. Merchants, conquerors and prophets were the first to transcend the binary division of us and them, foreseeing the potential unity of all mankind. For the merchants the entire world was one potential market. For the conquerors, the entire world was potentially a single empire. For the prophets, all humans were potential believers. 

Chapter 10 Money
The greatest unifier in history was possessed of extreme tolerance and adaptability, which managed to gain the allegiance of all people. This unifier is money. People who do not believe in the same god or obey the same king are more than willing to use the same money. Osama Bin Laden, for all his hatred of American culture, religion and politics, was very fond of American dollars. Why is money so all-conquering?

When Cortes and his conquistadors invaded Mexico, the Aztecs were puzzled by the Spanish obsession with gold. When asked why, Cortes replied, "Because I and my companions suffer from a disease of the heart which can be cured only with gold." In the world from which the Spaniards came, the obsession with gold was an epidemic. Even the bitterest of enemies lusted after the same useless yellow metal. 

Hunter-gatherers had no money. They had very limited goods and what they had was exchanged by barter. Even after the Agricultural Revolution, this did not change very much. Villages were self-sufficient with little division of labour. The rise of cities and kingdoms created new opportunities for specialisation - professional soldiers, shoemakers, carpenters, priests, lawyers. Specialisation created a new problem - how to manage the exchange of goods and services? Barter is only effective in a limited range of products. It cannot form the basis of a complex economy. 

Money is the universal medium of exchange that enables people to convert almost everything into almost anything else. Cowry shells were used as money for about 4,000 years in Asia, Oceania and Africa. Everyone always wants money because everyone else also always wants money. Physical money has no intrinsic value but is a psychological construct. Money is the most universal and most efficient system of mutual trust ever devised. This trust is due to a very complex and long-term network of political, social and economic relations. We believe in the dollar because we trust in the US Treasury. Initially, the network of trust had not been built up, so the first form of money - Sumerian barley - had intrinsic value. The next innovation was the silver shekel ingot. Harari reminds us that being of silver, this had no intrinsic value, as silver is too soft to be used for tools or weapons. The value of silver and gold is purely cultural, as they are useful only for ornaments. The first coins appeared around 640 BC in Anatolia. As long as people trusted the power and integrity of the king, they trusted his coins. Roman coins could even be used in far-away India. By the late modern era the entire world was a single monetary zone, relying first on gold and silver, and later on a few trusted currencies, such as the British pound and the American dollar. 

Why should everyone in every culture value gold and silver? If it were the case that gold were valued in Europe but not in India then merchants would buy gold cheaply in India and take it to Europe, where they would sell it dearly. In consequence, gold would flood Europe, where the price would go down, and in India the price would go up as the demand for gold would skyrocket. Eventually, the price would even out between the two markets. The mere fact that Europeans believed in gold would cause Indians to believe in it and also to value it. The difference between religion and money is that religion asks us to believe in something, whereas money asks us to believe that other people believe in something. Money is the only trust system invented by humans that can bridge almost any cultural gap. It does not discriminate on the basis of religion, race, gender, age or sexual orientation. Thanks to money, people who don't know each other and don't trust each other can nevertheless cooperate effectively. Without this shared belief in gold and silver, global trade would have been virtually impossible. 

Money operates according to two principles - universal convertibility (everything has a price) and universal trust - any two people can cooperate on any project. If you have money you can always employ someone to do your bidding.

The dark side of this is that money corrodes local traditions, intimate relations and human values, replacing them with the cold laws of supply and demand. In the extreme case, everything can be bought.

In Soviet Russia the theory was that everyone would work according to their capacity, and receive according to their needs, but in practice everyone worked as little as they could get away with, and received as much as they could grab.

Chapter 11 Empires
Most past cultures have sooner or later fallen prey to the armies of some ruthless empire, which have consigned them to oblivion. Empires too, ultimately fail, but they tend to leave behind rich and enduring legacies. Almost all people in the 21st century are the offspring of one empire or another. 

An empire is a political order that rules over more than say three peoples, each of which have their own cultural identity and separate territory. It need not be large in territorial extent. Empires also have an appetite for expansion. Empires were one of the main reasons for the drastic reduction in human diversity. Empire has been the world's most common form of political organisation for the last 2,500 years. Empire is a stable form of government. Conquered peoples have a poor record of freeing themselves from their imperial overlords. Typically, they have been been slowly digested by the conquering empire, until their distinct cultures fizzled out. 

The standard imperial toolkit included wars, enslavement, deportation and genocide. However, to colour all empires black and to disavow all imperial legacies is to reject most of human culture. Empires have played a decisive part in amalgamating many small cultures into fewer big cultures. Most imperial elites earnestly believed that they were working for the general welfare of all the empire's inhabitants. The Romans justified their dominion by arguing they were endowing the barbarians with peace, justice and refinement. Many Americans nowadays maintain that their government has a moral imperative to bring Third World countries the benefits of democracy and human rights, even if these are delivered by cruise missiles and F-16s. 

Evolution has made Sapiens, like other social mammals, a xenophobic creature. Sapiens instinctively divide humanity into two parts - us and them. Empires have tended to blur this distinction between the conquered and the conquerors over time.

Chapter 12 Religion
Religion was the third great unifier of humankind, alongside money and empires. All social orders and hierarchies are imagined and hence are fragile. The larger the society the more fragile it is. The crucial historical role of religion has been to give superhuman legitimacy to those fragile structures. Religion asserts that our laws are ordained by an absolute and indisputable authority. Harari defines religion as a system of human laws that is founded on a belief in superhuman laws. Religion meets two criteria: that it is an entire system of laws, and that it must claim to be based on superhuman laws, rather than on human ideas. For a religion to unite disparate groups of human beings living in a large expanse of territory, a religion must meet two criteria. It must espouse a universal superhuman order that is true always and everywhere, and it must insist on spreading this belief to everyone. In other words, it must be universal and missionary. Most ancient religions were local and had no interest in converting the entire human race. Universal and missionary religions began to appear in the first millennium BC. Their emergence was one of the most important revolutions in history. 

The first religions were animist and they were local in nature. Hunter-gatherers did not feel superior to plants and animals. In contrast, farmers owned and manipulated plants and animals. The religious effect of the Agricultural Revolution was to turn plants and animals from equal members of a spiritual round table into property. Much of ancient mythology is a legal contract in which humans promise everlasting devotion to the gods in exchange for mastery over plants and animals. Humans sacrificed lambs, wine and cakes to divine powers, who in exchange promised abundant harvests and fecund flocks. Originally, most of peoples' needs could be met by local spirits, but when kingdoms and trade networks expanded, people needed to contact entities whose power and authority spanned a large area. 

This led to the creation of polytheistic religions, according to which the world was controlled by powerful gods, such as the fertility goddess, the rain god, and the war god. Humans could propitiate these gods with sacrifices to bring health, rain and victory. Yet the spirits venerated in animism did not disappear. In fact, the common people continued to resort to them. The main change brought about by polytheism was in the status of Sapiens. In animism, humans were just one of many creatures inhabiting the world. By contrast, polytheists saw the world as a reflection of the relationship between gods and humans. Polytheism exalted not only the status of the gods but also that of humankind. 

Most polytheistic religions and even most animist religions recognise a single power or law governing the entire universe and that stands behind all the different gods. Greek mythology had Gaia or Fate, Hinduism has Brahman. However, the fundamental insight of polytheism, which distinguishes it from monotheism, is that the supreme power governing the world is devoid of interests and biases. It is unconcerned with the worries and desires of humans. There is no point in making sacrifices to such a god. Precisely because their powers are partial rather than all-encompassing, gods such as Ganesh, Lakshimi and Saraswati have interests and biases. Humans can therefore strike deals with these deities in order to win battles or recover from illness. 

Because they believe in one supreme and disinterested power and many partial and biased powers, there is no difficulty in accepting the efficacy of foreign gods. Polytheism is inherently open-minded and rarely persecutes heretics or infidels. Polytheistic religions do not seek to convert subject peoples. The only god that the Romans long refused to tolerate was the Christian one. This was because the refusal of the Christians to respect their gods was seen by the Romans as subversion. In three centuries, the polytheistic Romans killed no more than a few thousand Christians. In contrast, during the next 1,500 years, Christians slaughtered Christians by millions to defend slightly different interpretations of the religion of love and compassion. On 24 August 1572, French Catholics, who stressed the importance of good deeds, attacked communities of French Protestants, who highlighted God's love for humankind. Between 5,000 and 10,000 Protestants were slaughtered in less than 24 hours. When the Pope heard the news he was overcome with joy and organised festive prayers to celebrate the occasion. More Christians were killed by fellow Christians in those 24 hours than by the polytheistic Roman Empire throughout its entire existence. 

With time, some followers of polytheistic religions became so fond of their particular patron that they began to believe He was the supreme power of the universe. Yet crucially, they continued to believe that they could strike deals with Him. The first such religion was Atenism in Ancient Egypt. Judaism evolved out of polytheistic Canaanite religion, beginning with Yahweh, a storm-and-warrior deity. Christianity in turn, sprang out of Judaism, a local religion which was limited to one small area and only one people, the Jews. Christianity was the first evangelical religion. In one of history's strangest twists, this esoteric Jewish sect took over the mighty Roman Empire. 

Monotheists have been far more fanatical and missionary than polytheists. Since they usually believe that they are in possession of the entire message from the one and only God, they have been compelled to discredit all other religions. Monotheists violently exterminated all opposition. Today, most people outside East Asia adhere to a monotheist religion. Yet just as animism continued to survive within polytheism, so did polytheism survive within monotheism. The supreme power seems too distant and alien for the mundane needs of most people. In Christianity there are the cults of the various saints, which differ little from those of the polytheistic gods. The most prominent is the cult of Mary, who is more popular than Christ in South America. The Christian saints did not merely resemble the old polytheistic gods. Often they were these very same gods in disguise. For instance, the chief goddess of Celtic Ireland prior to Christianity was Brigid. St Brigit is to this day the most revered saint in Catholic Ireland. 

Polytheism gave birth not only to monotheist religions, but also to dualistic ones. Unlike monotheism, dualism holds that evil is an independent power, neither created by the good God nor subordinate to it. Dualism is attractive because it has a simple answer to the question of why there is evil in the world. Monotheists have to practise intellectual contortions to explain how an all-knowing, all-powerful and perfectly good God allows so much suffering in the world. The usual explanation given is that evil is needed to allow free will. Yet if a person chooses evil and consequently ends up roasting forever in hell then why did God create them? Dualism does not have this difficulty - it's Satan's fault. 

However, dualism has its own problems. If Good and Evil battle for control of the world then who enforces the laws governing the cosmic war? So monotheism explains order, but is mystified by evil. Dualism explains evil, but is puzzled by order. The logical way to solve the riddle is to argue that there is a single omnipotent God who created the entire universe - and He is evil. Nobody in history has had the stomach for such a belief. 

Jewish, Christian and Muslim monotheism absorbed dualist beliefs. Countless Christians, Muslims and Jews believe in a powerful evil force, called the Devil by Christians. Dualism is logically incompatible with monotheism. However, humans have a remarkable capacity to believe in contradictions. Millions of religious Jews, Christians and Muslims simultaneously believe in an omnipotent God and in an independent Devil. Many even believe that the good God needs our help against the Devil, which has inspired jihads and crusades. Monotheism is a kaleidoscope of monotheist, dualist, polytheist and animist legacies. The average Christian believes in the monotheist God, the dualist Devil and polytheist saints. 

Chapter 13 History
Harari explains the difference between describing how a historical event took place versus explaining why it happened. To explain 'how' means to reconstruct the series of events that led from one point to another. To explain 'why' means to find causal connections that account for the occurrence of this particular series of events to the exclusion of all others. One of the features of history as a discipline is that the better you know a particular period the harder it is to explain why things happened one way and not another. The people who knew the period best - those alive at the time - were the most clueless of all. It is an iron rule of history that what looks inevitable in hindsight was far from obvious at the time. It is important to realise that possibilities which seem very unlikely to contemporaries often get realised. When Constantine assumed the throne in 306, Christianity was little more than an esoteric Eastern sect. If you were to suggest it was about to become the Roman state religion you would have been laughed out of the room, just as you would be today if you were to suggest that by 2050 Hare Krishna would be the state religion of the USA. 

Chapter 14 The Scientific Revolution
Modern science differs from all previous traditions of knowledge in three ways. 1) The willingness to admit ignorance and that even the things we think we know could be proven wrong in the future. 2) The centrality of observation and mathematics. 3) The acquisition of new powers, ie technologies.

The great discovery that launched the Scientific Revolution was that humans do not know the answers to their most important questions. Premodern traditions, such as Islam, Buddhism and Confucianism, asserted that everything that was important to know about the world was already known. The gods possessed all-encompassing wisdom, which they revealed to us in scriptures and oral traditions. Ancient traditions of knowledge admitted only two kinds of ignorance. First, an individual could be ignorant of something important. All they needed to do was ask somebody wiser. There was no need to discover something that nobody yet knew. Second, an entire tradition might be ignorant of unimportant things. Whatever the great gods and the wise people of the past did not bother to tell us was unimportant. For instance, if someone wanted to know how spiders weave their webs they would not find the answer in the Bible. This was because such knowledge was unimportant. If it were important than God would have included an explanation in the Bible. 

Modern science is a unique tradition of knowledge because it openly admits collective ignorance regarding the most important questions. 

Until the Scientific Revolution most human cultures did not believe in progress. They thought the Golden Age was in the past, and that the world was stagnant, if not deteriorating. It was considered impossible that human ingenuity could overcome the world's fundamental problems. 

Scientific research is expensive and hence it can flourish only in alliance with an ideology. The ideology justifies the cost of the research. In exchange, the ideology influences the scientific agenda and determines what to do with the discoveries. To understand the development of science we have to take into account the ideological, political and economical forces that shaped science and pushed it in certain directions while neglecting others. The feedback loop between science, empire and capital has arguably been history's chief engine for the last 500 years. 

Chapter 15 The Marriage of Science and Empire
Shortly before Cook's voyage of 1770, Western Europe was but a distant backwater of the Mediterranean world. Only at the end of the 15th century did Europe become a hothouse of military, political, economic and cultural developments. Between 1500 and 1750, western Europe became master of the two Americas and of the oceans. Yet even then Europe was no match for the great powers of Asia: the Ottoman Empire, the Safavid Empire of Persia, the Mughal Empire in India and China. Europeans managed to conquer the Americas and gain supremacy at sea mainly because the Asians showed little interest in them. In 1775 Asia accounted for 80% of the world economy. Europe was an economic dwarf. The balance of power shifted to Europe between 1750 and 1850, when Europeans humiliated the Asian powers in a series of wars and conquered large parts of Asia. By 1900, Europeans controlled the world's economy and most of its territory. In 1950 western Europe and the US together accounted for more than half of global production, whereas China's portion had shrunk to 5%. Under the European aegis a new global order and global culture emerged. "They may be fiercely anti-European in their rhetoric, but almost everyone on the planet views politics, medicine, war and economics through European eyes, and listens to music written in European modes."

From 1850 onward, European domination of the world rested on its military, industrial and technological superiority. In 1880 the West had 350,000 km of railroads, whereas the rest of the world possessed a tenth of that, and most of these were laid by the British in India. 

Why didn't the Chinese and Persians follow suit? Steam engines could be freely copied or bought. They lacked the values, myths and judicial apparatus and socio-political structures that took centuries to form and mature in the West and which could not be copied and internalised rapidly. Between 1500 and 1850 Europe did not enjoy any obvious technological, political, military or economic advantage over the Asian powers, yet the continent built up a unique potential, whose importance suddenly became obvious around 1850. 

The basis of Europe's superiority came down to two factors: science and capitalism. 

What distinguishes European imperialism from all previous imperial projects is that, unlike all past conquerors, the Europeans sought new knowledge as well as new territories. In the 18th and 19th centuries, almost every important military expedition that left Europe for distant lands took scientists with them. Napoleon took 165 scholars with him when he invaded Egypt in 1798. Among other things, they founded the new discipline of Egyptology. The voyage of the Beagle is even more famous and important. Much earlier, Columbus made landfall at the Bahamas, believing they were part of East Asia. He never realised that he had discovered a new continent because he had the medieval mindset that the entire world - consisting of Europe, Asia and Africa - was already known. It fell to Amerigo Vespucci to be the first to realise that Columbus had discovered a new continent. 

During the 15th and 16th centuries, European expeditions circumnavigated Africa, explored America, crossed the Pacific and Indian Oceans, and created a network of bases and colonies all over the world. The European imperial expeditions transformed the history of the world from being a series of histories of peoples and cultures to a single integrated human society. Yet the Chinese possessed a much more impressive fleet in the early 15th century. Europeans did not possess a major technological edge. What made them exceptional was their unparalleled and insatiable ambition to explore and conquer. 

The Spaniards conquered the Aztec Empire in 1521, within four years of discovering it. The previous rulers of Central America - the Aztecs, Toltecs and Maya - barely knew South America existed and never made any attempt to subjugate it, over the course of 2,000 years. Yet within little more than ten years of the conquest of Mexico, Pizarro had discovered the Inca Empire, and vanquished it in 1532. So within 40 years of the discovery of the Americas, its two powerful empires were extinguished by the Spanish. 

The Aztecs and Incas paid dearly for their insularity. The Spaniards conquered most of the Caribbean islands and established colonies before Cortes landed in Mexico. For the subjugated natives these colonies were hell on earth. The native population was enslaved and made to work in mines and plantations in cruel conditions.  Within 20 years almost the entire native Caribbean population was wiped out. The Spaniards replaced them with imported African slaves. This genocide took place on the doorstep of the Aztec Empire, yet the Aztecs knew nothing about it. The coming of the Spaniards was like an invasion from outer space. The Aztecs were convinced that they knew the entire world and that they ruled most of it. 

The Aztecs were bewildered by the Spaniards. Instead of wiping out the Spaniards, they deliberated, dawdled and negotiated. After all, what could Cortes do with 550 men against an empire of millions? The Aztecs allowed the Spaniards to march to their capital and ushered them into the presence of Montezuma II. In the middle of the interview, Cortes gave a signal and the steel-armed Spaniards butchered the emperor's bodyguards, who only had wooden clubs and stone blades. Cortes was now in a delicate situation. He had captured the emperor, but was surrounded by tens of thousands of enemy warriors, millions of hostile civilians, and an entire continent about which he knew practically nothing. Cortes made it appear that Montezuma was free and still in charge. This paralysed the empire, which was extremely centralised. Montezuma continued to behave as though he ruled, and the Aztec elite continued to obey him, which meant they obeyed Cortes. This situation continued for months. Cortes used the time to train translators in various local languages and to send small expeditions to become familiar with the Aztec Empire. 

The Aztec elite eventually rebelled against Cortes and Montezuma, elected a new emperor and drove the Spaniards from Tenochtitlan. However, by then, numerous cracks had appeared in the imperial edifice. Cortes used the knowledge he had gained to prise the cracks open wider and split the empire from within. He convinced many of the empire's subject peoples to join him against the Aztecs. The subject peoples hated the Aztecs but knew nothing about Spain or the Caribbean genocide. The idea that the Spanish would take over from the Aztecs never occurred to them. They thought that if Cortes and his few hundred henchmen caused any trouble, they could easily be overwhelmed. The rebellious peoples provided Cortes with an army of tens of thousands of local troops and with its help Cortes besieged Tenochtitlan and conquered the city. 

Within a century of Cortes' landing at Veracruz, the native population of the Americas had shrunk by about 90%, mainly due to imported diseases. The survivors found themselves under the thumb of a greedy and racist regime that was far worse than the Aztecs. 

Ten years after Cortes landed in Mexico, Pizarro landed on the shore of the Inca Empire with just 168 men. Yet Pizarro benefitted from all the knowledge and experience gained in previous invasions. The Inca, in contrast, knew nothing about the fate of the Aztecs. Pizarro plagiarised Cortes. He declared himself a peaceful emissary from the king of Spain, invited Atahualpa, the Inca ruler, to a diplomatic interview, and then kidnapped him. Pizarro proceeded to conquer the paralysed empire with the help of local allies. 

The native peoples of America were not the only ones to pay a heavy price for their parochial outlook. The great empires of Asia - the Ottoman, the Safavid (Persia), the Mughal and the Chinese - soon heard about the discovery of the Americas. Yet they showed little interest, as they continued to believe the world revolved around Asia and made no attempt to compete with the Europeans for control of the Americas, nor of the Atlantic and Pacific. The first Chinese world map to show America was not issued until 1602 - and then by a European missionary. For 100 years, the Europeans enjoyed undisputed mastery in America, Oceania, the Atlantic and the Pacific. The only significant struggles in those regions were between different European powers. The wealth and resources accumulated by the Europeans eventually enabled them to invade Asia too, defeat its empires and divide it among themselves. When the Ottomans, Persians, Indians and Chinese woke up and paid attention, it was too late.

Only in the 20th century did non-European cultures adopt a truly global vision. European hegemony was broken. The Algerians and the Vietnamese defeated the French and the US super-power respectively. 

Building an empire and advancing scientific knowledge went hand-in-hand for the British. When they conquered India they brought archeologists to study Indian history, anthropologists to study Indian cultures, geologists to study Indian soils and zoologists to study Indian fauna. The Great Survey of all of India took them 60 years to complete. None of India's pre-British rulers had shown any interest in the ruins of Mohenjo-daro, one of the chief cities of the Indus Valley civilisation, which flourished in the third millenium BC and was destroyed around 1900 BC. A British team excavated it and discovered the first great civilisation of India, which no Indian had been aware of. Another major feat in the mid-19th century, was the deciphering of cuneiform by Rawlinson, a British officer who devoted his spare time to the project. 

The British imperialists knew India better than any previous conqueror, and even than the native population itself. Their superior knowledge had obvious practical advantages. Without such knowledge, it is unlikely that a ridiculously small number of Britons could have governed, oppressed and exploited hundreds of millions of Indians for two centuries. Throughout the 19th and early 20th centuries, fewer than 5,000 British officials and about 40,000 to 70,000 British soldiers were sufficient to conquer and rule 300 million Indians. 

Without the practical knowledge, ideological justification and technology that scientists provided, it is doubtful that the Europeans could have conquered the world. Conversely, without imperial support it is doubtful whether modern science would have progressed very far. 

Chapter 16 Capitalism
To understand modern economic history you need to understand a single word: growth. In 1500 annual per capita production averaged $550, today it is $8,800. 

In the USA banks are allowed to loan $10 for every dollar they actually have. If all of the account holders withdrew their funds from the bank then it would collapse. What enables banks and the whole economy to survive and flourish is our trust in the future. This trust is the sole backing for most of the money in the world. Before the modern era money could represent things that actually existed in the present. This imposed a severe limitation on growth, since it made it very hard to finance new enterprises. Economies remained frozen until the appearance of a new system in the modern era, based on trust in the future. People agreed to represent goods that do not exist in the present with a special kind of money called credit. Credit allows 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.

Credit has existed since the dawn of civilisation, however, in the past people seldom wanted to extend much credit because they didn't trust that the future would be better than the present. They tended to believe that the past was better than their own times and that the future would be worse, or at best much the same. They believed that the total amount of wealth was limited, if not dwindling. 

It was a lose-lose system. Because credit was limited, people had trouble financing new businesses. Because there were few new businesses the economy did not grow. Because it did not grow people assumed it never would. Stagnation was a self-fulfilling prophecy. 

Then came the Scientific Revolution and the idea of progress. The idea of progress is that if we admit our ignorance and invest resources in research, things can improve. Geographical discoveries, technological inventions and organisational developments increased the sum total of human production, trade and wealth. Trust in the future created credit, which brought real economic growth, which strengthened trust in the future, and so on. According to Adam Smith's 1776 manifesto, The Wealth of Nations, which was radical in its time, people become rich by increasing the overall size of the pie. If I am poor, you too will be poor because I cannot buy your products or services. If I am rich you too will be enriched since you can now sell me something. A crucial part of the new ethic was that profits would be reinvested in production. 

"Capitalism's belief in perpetual economic growth flies in the face of almost everything we know about the universe. A society of wolves would be extremely foolish to believe that the supply of sheep would keep on growing indefinitely. The human economy has nevertheless managed to keep on growing throughout the modern era, thanks only to the fact that scientists came up with another gadget or discovery every few years - such as the continent of America, the internal combustion engine or genetically engineered sheep. Banks and governments print money, but ultimately it is the scientists who foot the bill. Over the last few years, banks and governments have been frenziedly printing money. Everybody is terrified that the current economic crisis may stop the growth of the economy. So they are creating trillions of dollars, euros and yen out of thin air, pumping cheap credit into the system, and hoping that the scientists, technicians and engineers will manage to come up with something really big, before the bubble bursts. Everything depends on the people in the labs. New discoveries in fields such as biotechnology and artificial intelligence could create entire new industries, whose profits could back the trillions of make-believe money that the governments and banks have created since 2008. If the labs do not fulfil these expectations before the bubble bursts, we are heading towards very rough times."

Capitalism played a decisive role not only in the rise of modern science, but also in the emergence of European imperialism. It was European imperialism that created the capitalist credit system in the first place.

In Asia, the great empire builders did not care about the interests of bankers and investors. They were content to finance wars through taxes and plunder (without making fine distinctions between the two). In Europe, kings and generals gradually adopted the mercantile way of thinking, until merchants and bankers became the ruling elite. The European conquest of the world was increasingly financed through credit rather than taxes, and was increasingly directed by capitalists, whose main ambition was to receive maximum returns on their investments. The mercantile empires were much shrewder in financing their conquests: nobody wants to pay taxes, but everyone is happy to invest.

Ferdinand and Isabella invested in Columbus' risky expedition, which both literally and metaphorically, opened up a gold mine for Spain. A hundred years later, princes and bankers were willing to extend far more credit to Columbus' successors, and they had more capital at their disposal, thanks to the treasures reaped from America. The magic circle of imperial capitalism was in place: credit financed new discoveries, discoveries led to colonies, colonies provided profits, profits built trust, and trust translated into more credit. The great conquerors Nurhaci and Nader Shah ran out of fuel after a few thousand kilometres. Capitalist entrepreneurs only increased their financial momentum from conquest to conquest.  

The Mississippi Bubble was one of history's most spectacular financial crashes. In 1717 the Mississippi Company, chartered in France, set out to colonise the lower Mississippi valley, establishing New Orleans in the process. To finance its ambitious plans the company sold shares on the Paris stock exchange. John Law was the company's director, as well as the governor of the bank of France. As well, he was appointed by the king to a post roughly equivalent to finance minister. The lower Mississippi valley was mainly swamps, yet the Mississippi  Company spread tales of fabulous riches and boundless opportunities. French aristocrats, businessmen and the bourgeoisie fell for these fantasies. Mississippi share prices skyrocketed from 500 livres to 10,000. Euphoria swept the streets of Paris. People sold their possessions and took huge loans in order to buy Mississippi shares. All believed they'd discovered the easy way to riches. 

A few days after the shares passed 10,000, the panic began. Some speculators realised that the share price was totally unrealistic and unsustainable. They sold while the price was still high. This caused the price to go down, creating a snowball effect. In order to stabilise prices, the central bank of France, directed by John Law, bought up Mississippi shares. However, it ran out of money. When this happened, John Law, in his capacity of controller-general of finances, authorised the printing of money in order to buy more shares. This placed the entire French financial system inside the bubble. Despite this, the share price totally collapsed. So the central bank and the royal treasury owned a huge amount of worthless stock and had no money. The big speculators emerged largely unscathed, as they had sold in time. Small investors lost everything and many committed suicide. 

The royal French financial system never recuperated fully from this blow. People lost faith in the French financial system. It was one of the chief reasons why the overseas French Empire fell into British hands. 

The most notorious example of how governments did the bidding of big money was the First Opium War, fought between Britain and China (1840-1842). In the first half of the 19th century, the British East India Company and sundry British business people made fortunes by exporting drugs, particularly opium, to China. Millions of Chinese became addicts, debilitating the country, both economically and socially. In the late 1830s the Chinese government banned drug trafficking, but British drug merchants simply ignored the law. Chinese authorities began to confiscate and destroy drug cargoes. The drug cartels had close connections in Westminster and Downing Street, and many MPs and cabinet ministers held stock in the drug companies. So they pressured the government to take action. 

In 1840 Britain declared war on China in the name of free trade. The Chinese were no match for British arms - steamboats, heavy artillery, rockets and rapid-fire rifles. China was forced to allow the British drug merchants to operate freely and to compensate them for damages inflicted by the Chinese police. The British took control of Hong Kong, which they used as a secure base for drug trafficking. In the late 19th century, 40 million Chinese, a tenth of the population, were opium addicts. 

War itself could become a commodity, just like opium. In 1821 the Greeks rebelled against the Ottoman Empire. The uprising aroused great sympathy in Britain, and London financiers saw an opportunity as well. They proposed to the rebel leaders the issue of tradeable Greek Rebellion Bonds on the London Stock Exchange. The Greeks would promise to repay the bonds. plus interest, if and when they won their independence. Investors bought bonds to make a profit, out of sympathy for the Greek cause, or both. The value of the bonds rose and fell in tempo with military successes and failures. The Turks gradually gained the upper hand. With a rebel defeat imminent, the bondholders faced the prospect of losing their investments. The bondholders' interest was the national interest, so the British organised an international fleet that, in 1827, sank the main Ottoman flotilla in the Battle of Navarino. After centuries of subjugation, Greece was finally free. But freedom came with a huge debt that the new country had no way of repaying. The Greek economy was mortgaged to British creditors for decades to come. 

Today, a country's credit rating is far more important to its economic well-being than are its natural resources. 

Harari writes that there is no such thing as a free market that is free of all political bias. The most important economic resource is trust in the future, and this resource is constantly threatened by thieves and charlatans. Markets by themselves offer no protection against fraud, theft and violence. It is the job of the political system to ensure trust by legislating sanctions against cheats and to maintain police forces, courts and gaols to enforce the law. When kings fail to do their jobs and regulate the markets properly, it leads to loss of trust, dwindling credit and economic depression. This was the lesson taught by the Mississippi Bubble of 1719, and anyone who forgot it was reminded by the US housing bubble of 2007, and the ensuing GFC.

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. When the Europeans conquered America, they opened gold and silver mines and established sugar, tobacco and cotton plantations. These became the mainstay of American production and export. Sugar plantations were particularly important after a great demand developed for this substance. Growing cane and extracting its sugar was labour-intensive. Few people wanted to work long hours in malaria-infested fields under a tropical sun. Greedy for profits and economic growth, European plantation owners switched to slaves. 

From the 16th to the 19th centuries, about 10 million slaves were imported to America. About 70% of them worked on the sugar plantations. Labour conditions were abominable. Most slaves lived a short and miserable life, and millions more died during wars waged to capture slaves or during transportation. The slave trade was not controlled by any state or government. It was a purely economic enterprise, organised and financed by the free market according to the laws of supply and demand. 

Chapter 17 The Wheels of Industry
The modern economy grows thanks to our trust in the future and the willingness of capitalists to reinvest their profits into production. However, economic growth also requires resources and energy, which are finite. Yet counter-intuitively, while humankind's use of energy and resources has mushroomed in the last few centuries, the amounts available for our exploitation have actually increased. Whenever a shortage threatened economic growth, scientific and technological research found new types of energy and materials. 

In the past, humans had only a single machine capable of converting one form of energy into another - the body. Bodies convert the energy in food and release it through the movement of muscles. Almost everything people did throughout history was fuelled by solar energy that was captured by plants and converted to muscle power. The steam engine, in 1700, was a huge breakthrough, one that ushered in the Industrial Revolution. The first commercial railway line, connecting Liverpool with Manchester, opened in 1830, just five years after the first steam locomotive. Just 20 years later, Britain had tens of thousands of kilometres of railway tracks. Citing the internal combustion engine and electricity, Harari contends that the Industrial Revolution was at heart a revolution in energy conversion. 

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 annually about as much energy as we receive from the sun in just 90 minutes.

Learning how to harness and convert energy effectively solved the other problem that slows economic growth - the scarcity of raw materials. As humans worked out how to harness large quantities of cheap energy, they could exploit previously inaccessible deposits and transport raw materials from ever more distant locations. Scientific breakthroughs allowed the creation of completely new raw materials, such as plastic, as well as to discover previously unknown natural materials, such as silicon and aluminium. For some decades, aluminium was more expensive than gold. 

In the wake of the Industrial Revolution, humans produce far more goods than ever before. Supply outstrips demand. An entirely new problem arose: who is going to buy all this stuff? Most people throughout history lived under conditions of scarcity. Frugality was their watchword. Yet the modern capitalist economy must constantly increase production if it is to survive. So a new ethic was born: consumerism. This sees the consumption of ever more products and services as a positive thing. It encourages people to treat themselves, spoil themselves and even kill themselves slowly by over-consumption. We live in an age of shopping. 

Traditional agricultural societies lived in the awful shade of starvation. In our affluent world one of the leading health problems is obesity. Each year, the US population spends more on diets than would feed all the hungry people in the rest of the world. Obesity is a double victory for consumerism. People eat too much and then buy diet products, contributing to economic growth twice over. 

In medieval Europe, aristocrats spent their money carelessly on extravagant luxuries, whereas peasants lived frugally, minding every penny. Today, the tables have turned. The rich take great care managing their assets and investments, while the less well-heeled go into debt buying things they don't really need. Most previous ethical systems presented people with a pretty tough deal. They were promised paradise, but only if they cultivated compassion, overcame craving and anger and restrained their selfish interests. This was too tough for most. The history of ethics is a sad tale of wonderful ideals that nobody can live up to. In contrast, most people today successfully live up to the capitalist-consumerist ideal. The new ethic promises paradise on condition that the rich remain greedy and spend their time making more money, and that the masses give free rein to their cravings and passions, buying more and more. This is the first religion in history whose followers actually do what they are asked to do. 

Chapter 18 A permanent revolution
A major change brought about by the Industrial Revolution was the introduction of timetables, which became the template for most human activities. By contrast, in an agrarian society, no-one cared what hour it was; only the cycles of day and night and the seasons mattered. In 1880 the British government mandated that all timetables in Britain must follow Greenwich, obliging the population to live according to an artificial clock. Today, a single affluent family generally has more timepieces than an entire medieval country. The Industrial Revolution brought about many other major upheavals: urbanisation, the disappearance of the peasantry, the rise of the industrial proletariat, the empowerment of the common person, democratisation, youth culture and the end of patriarchy. However, Harari thinks the greatest change was the collapse of the family and local community and their replacement by the state and the market.

Before the Industrial Revolution, the family was the welfare system, health system, education system, the construction industry, the pension fund, the radio, the bank and even the police. When there were problems the family could not resolve, such as a violent dispute or a new business that required a large investment, the local community stepped in. Neighbours exchanged favours without payment. Village life involved many transactions but few payments. There were markets, but their role was limited. Less than 10% of commonly used products and services were paid for. Transportation and communication difficulties made it difficult for a king to interfere in the affairs of remote communities, so in most cases he ceded even the most basic royal prerogatives - taxation and violence - to communities. 

Many kingdoms and empires were in truth little more than large protection rackets. The king made sure that neighbouring crime syndicates and local small fry did not harm those under his protection. He did little else. 

In the last two centuries, the market gained immense new powers, and the state gained new means of communication and transportation. The state acquired an army of clerks, teachers, policemen and social workers. At first, the market and the state found their path blocked by traditional families and communities, who had little love for outside intervention. However, the state and the market approached people with an offer they could not refuse. "Become individuals, marry whom you like, take what job suits you, live wherever you wish." The state and the market began to provide food, shelter, education, health, welfare and employment. Romantic literature often portrays the individual as being caught in a struggle against the state and the market. Nothing could be further from the truth. The state and the market are the mother and father of the individual, and the individual can only survive thanks to them. The market provides work, insurance and a pension. If we want to acquire a profession, the government is there to teach us. If we want to open a business the bank loans us money. If we are sick for a few days our health insurance takes care of us. If we need around-the-clock assistance, we can go to the market and hire a nurse - usually some stranger from the other side of the world who takes care of us with the kind of devotion that we no longer expect from our own children. 

Not only adult men, but also women and children, are recognised as individuals. Throughout most of history, women were often seen as the property of family and community. 

However, the liberation of the individual comes at a cost. Many of us feel alienated and threatened by the power the impersonal state and market wield over our lives. The deal between states, markets and individuals is an uneasy one. Yet it is amazing that this deal works at all - however imperfectly. For it breaches countless generations of human social arrangements. Millions of years of evolution have designed us to live and think as community members. Within a mere two centuries we have become alienated individuals. Nothing testifies better to the awesome power of culture. 

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 for 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. Mum and Dad are about as likely to get off in the Freudian courtroom as were the defendants in a Stalinist show trial. 

Markets and states supply the tribal bonds once provided by intimate communities. They do so by means of imagined communities, in which millions of people who don't know each other imagine that they do. Kingdoms, empires and churches functioned for millennia as imagined communities. The two most important modern communities are the nation and the consumer tribe. These are inter-subjective realities, which exist only in our collective imagination, yet their power is immense. The nation does its best to hide its imagined character. Most nations argue that they are a natural and eternal entity, created in some primordial epoch by mixing the soil of the motherland with the blood of the people.

The social order was stable and rigid, nowadays it is in a state of permanent flux. The seven decades since the Second World War were the most peaceful era in human history, by a wide margin. In 2002, of the 57 million people who died, only 172,000 died in a war and 569,000 died of violent crime, totalling 741,000. In contrast, 871,000 committed suicide. 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. As kingdoms and empires became stronger, they reined in communities and the level of violence decreased.

Of course, states also murder their own citizens. Yet during the worst years of the Brazilian dictatorship (which lasted from 1964 to 1985), the average Brazilian in Rio de Janeiro was far less likely to die at human hands than the average tribesman in the Amazon. In such tribes between a quarter and a half of their menfolk die in violent conflicts over property, women or prestige. 

It is debatable whether violence within states has decreased or increased since 1945. Yet it is undeniable that international violence has dropped to an all-time low. The most obvious example is the collapse of European empires. In past ages empires usually collapsed in a bloodbath, which generally led to anarchy and wars of succession. Since 1945 most empires have opted for peaceful retirement. In 1945 Britain ruled a quarter of the globe; thirty years later it had just a few small islands. The British retreated from most of their colonies in a peaceful manner. The French Empire was more stubborn, involving wars in Algeria and Vietnam. Yet the French too, retreated peacefully from most of their dominions. The Soviet collapse in 1989 was even more peaceful. Never before has such a mighty empire disappeared so swiftly and so quietly. The Soviets didn't suffer any military defeats, except for Afghanistan, had millions of soldiers and enough atomic weapons to wipe out humanity, yet they disbanded their empire without a fight. 

With very few exceptions, since 1945 states no longer invade other states in order to conquer and swallow them up. Such conquests have been the bread and butter of political history since time immemorial. Campaigns of conquest like those of the Romans, Mongols and Ottomans cannot take place today anywhere in the world. Since 1945, no independent country recognised by the UN has been conquered and wiped off the map. Wars still occur, but they are no longer the norm. Real peace is the implausability of war. The price of war has gone up dramatically. Nuclear weapons have turned war between superpowers into collective suicide. The profits of war have also declined. In the past, most wealth consisted of material things like fields, cattle, slaves and gold, so it was easy to occupy or loot it. Today, wealth consists mainly of human capital and organisational know-how. Peace also became more lucrative than ever. This is due to international trade. 

There has been a tectonic shift in global political culture. Many elites in history viewed war as a positive good. Others viewed it as a necessary evil. Ours is the first historical period in which the elite - politicians, business people and intellectuals - see war as both evil and avoidable. 

The tightening web of international connections erodes the independence of most countries, lessening the chance that one of them might start a war. 

Chapter 19
Did the power and wealth developed by humankind over the last centuries make us happier? It could be argued that there is a reverse correlation between human capabilities and happiness. As humankind gained more and more power, it created a cold mechanistic world ill-suited to our real needs. Evolution moulded our minds and bodies to the life of hunter-gatherers. Medieval peasants may indeed have been more miserable than their hunter-gatherer forbears. However, the last few centuries have seen the triumphs of modern medicine; there has been a steep drop in violence and the near elimination of large-scale famines. On the other hand, it appears that we are destroying the foundations of human prosperity in an orgy of reckless consumption. 

Philosophers, priests and poets have brooded over the nature of human happiness for millennia, and many have concluded that social, ethical and spiritual factors have as great an impact on our happiness as material conditions. People in modern societies suffer from alienation and meaninglessness. Perhaps our less well-to-do ancestors found much contentment in community, religion and a bond with nature. 

Happiness is generally defined as "subjective well-being". One finding is that illness decreases happiness in the short term, but is a source of long term distress only if the person is constantly deteriorating or has chronic pain. People with strong families who live in tight-knit and supportive communities are significantly happier than those who don't. There is a very close correlation between good marriages and high subjective well-being, as well as between bad marriages and misery. The most important finding is that happiness does not depend on objective conditions such as wealth, health or even community. Rather, it depends on the correlation between objective conditions and subjective expectations. This is why winning the lottery has 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. When things deteriorate, expectations shrink, and consequently even a severe illness might leave you pretty much as happy as you were before. 

We moderns have an arsenal of tranquilisers and pain killers 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. Trying to imagine how happy people were in the past, we inevitably imagine ourselves in their shoes. But that won't work because it pastes our expectations onto the material conditions of others. Medieval peasants went without washing for months on end. The very thought of living like that, filthy and reeking, is abhorrent to us. Yet medieval peasants probably did not mind. 

Biologists hold that our mental and emotional world is governed by biochemical mechanisms in our nerves and neurons, as well as substances like serotonin, dopamine and oxytocin. Unfortunately, our internal biochemical system seems to be programmed to keep happiness levels relatively constant. Human happiness levels differ from person to person. People are born with a cheerful or gloomy system. Happy and unhappy events raise or lower the level of contentment for a while, but it returns to its steady value. 

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 Nietzsche put it, if you have a why to live, you can bear almost any how. A meaningful life can be extremely satisfying even in the midst of hardship, whereas a meaningless life is a terrible ordeal no matter how comfortable one is. 

Medieval people were probably happy because of their delusions of an afterlife. Yet the other-worldly meanings medieval people found in their lives were no more deluded than the humanist, nationalist and capitalist meanings modern people find. The scientist who says her life is meaningful because she increases the store of human knowledge, the soldier who declares that his life is meaningful because he fights to defend his homeland, and the entrepreneur who finds meaning in building a new company are no less deluded than their medieval counterparts who found meaning in reading scriptures, going on a crusade or building a cathedral. So perhaps happiness is synchronising one's personal delusions of meaning with the prevailing collective delusions. But does happiness really depend on self-delusion?

Whatever we do throughout our lives, whether scratching our leg or fighting a war, we are just trying to get pleasant feelings. Buddhism holds that the root of suffering is the never-ending and pointless pursuit of ephemeral feelings, which causes us to be in a state of permanent tension, restlessness and dissatisfaction. The solution is to stop craving feelings. Buddha's recommendation was to stop not only the pursuit of external achievements, but also the pursuit of inner feelings.

Chapter 20 The end of Homo Sapiens
Sapiens is beginning to break free of the limits of its own biology. Mankind has practised selective breeding of animals and plants for thousands of years in order to produce animals and plants that better suited our needs. Now it is possible to do much more. Scientists can take specific genes from one organism and implant it into the DNA of another. For instance, a French geneticist created a rabbit that glows with a green colour by taking a gene from a fluorescent jellyfish. Another example is something that looks like an ear that was made to grow on the back of a mouse. The bacterium E. Colli has been engineered to produce insulin more cheaply than by other methods. A gene extracted from an Arctic fish has been inserted into potatoes, making them more frost resistant. Geneticists have managed to extend sixfold the life expectancy of worms and to create mice with much improved memory and learning skills. Although most species of voles are promiscuous, one species is monogamous. Geneticists claim to have isolated the genes responsible for vole monogamy. Scientists plan to resurrect mammoths using the mapping of their genome. There is even a suggestion that we might recreate a living Neanderthal. 

There is speculation that genetic engineering could produce a race of supermen. Harari believes that within a few decades genetic engineers might be able to make far-reaching alterations to our physiology, immune system, life expectancy, and even our intellectual and emotional capacities. 

The Cognitive Revolution that turned Homo Sapiens from an insignificant ape into the master of the world did not require any noticeable change in physiology or even in the size and external shape of the Sapiens brain. It apparently involved no more than a few small changes to internal brain structure. Perhaps another small change would be enough to ignite a second Cognitive Revolution, creating a completely new type of consciousness, and transform Homo Sapiens into something altogether different. 

Another new technology that could change the laws of life is the creation of cyborgs, beings which combine organic and inorganic parts, such as a human with bionic hands. Jesse Sullivan has bionic arms that replace those he lost. He moves his arms by thought alone. Another example are bionic ears. These consist of a microphone and an implant that filters the sounds, identifies human voices and translates them into electrical signals, which are sent to the brain. There is a similar device that allows blind people to regain partial vision, good enough to identify letters and even recognise faces. It may be possible in the future to read peoples' minds and to directly share their consciousness.

A third strand is artificial intelligence that is able to learn and develop in ways not built into it by its designers. Such programs can evolve beyond anything known to their creators. Driverless cars and self-instructing chess programs, such as AlphaZero, are examples of artificial intelligence. The Human Brain Project hopes to recreate an entire human brain inside a computer. In 2013 the project received a grant of 1 billion euros from the European Union.

Unless some nuclear or ecological catastrophe destroys us first, the pace of technological developments will soon lead to the replacement of Homo Sapiens by completely different beings who possess not only different physiques, but also very different cognitive and emotional worlds. 

Afterword: the animal that became a god
Seventy thousand years ago Homo Sapiens was an insignificant ape minding its own business in a corner of Africa. In the following millennia it transformed itself into the master of the entire planet and the terror of the ecosystem. Today it stands on the verge of becoming a god, poised to acquire not only eternal youth, but also divine abilities of creation and destruction. We have mastered our surroundings, increased food production, built cities, developed advanced technology, established empires and created far-flung trade networks. Yet time and again, massive increases in human power did not necessarily improve the well-being of individual Sapiens, and usually caused immense misery to other animals. 

Despite the astonishing things humans are capable of doing, we remain unsure of our goals and we seem as discontented as ever. We have advanced from canoes to space shuttles, but nobody knows where we are going. We are more powerful than ever before, but we have very little idea what to do with all that power. Worse still, humans seem to be more irresponsible than ever. Self-made gods with only the laws of physics to constrain us, we are accountable to no-one. We are consequently wreaking havoc on our fellow animals and on the surrounding ecosystem, seeking little more than our own comfort and amusement, yet never finding satisfaction.

Is there anything more dangerous than dissatisfied and irresponsible gods who don't know what they want?

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The above is Harari's summing up of the story of humanity. I would add that we live in a schizoid world. Democratic states that are economically and technologically advanced co-exist with regimes such as those of North Korea and the Taliban, which have created the most backward dystopias. While part of humanity looks to progress and positive change, other parts are set to return to the darkest corners of our collective past.