Homo Deus: A Brief History of Tomorrow

by Yuval Noah Harari

the animist grand opera into a dialogue between man and gods. During the Scientific Revolution humankind silenced the gods too. The world was now a one-man show. Humankind stood alone on an empty stage, talking to itself, negotiating with no one and acquiring enormous powers without any obligations.

Whereas the Agricultural Revolution gave rise to theist religions, the Scientific Revolution gave birth to humanist religions, in which humans replaced gods. While theists worship theos (Greek for ‘god’), humanists worship humans.

Industrial farming sanctifies human needs, whims and wishes, while disregarding everything else.

One of the wonderful things about science is that when scientists don’t know something, they can try out all kinds of theories and conjectures, but in the end they can just admit their ignorance.

some scientists concede that consciousness is real and may actually have great moral and political value, but that it fulfils no biological function whatsoever. Consciousness is the biologically useless by-product of certain brain processes.

Jet engines roar loudly, but the noise doesn’t propel the aeroplane forward. Humans don’t need carbon dioxide, but each and every breath fills the air with more of the stuff. Similarly, consciousness may be a kind of mental pollution produced by the firing of complex neural networks. It doesn’t do anything. It is just there. If this is true, it implies that all the pain and pleasure experienced by billions of creatures for millions of years is just mental pollution. This is certainly a thought worth thinking, even if it isn’t true. But it is quite amazing to realise that as of 2016, this is the best theory of consciousness that contemporary science has to offer us.

According to current scientific dogma, everything I experience is the result of electrical activity in my brain, and it should therefore be theoretically feasible to simulate an entire virtual world that I could not possibly distinguish from the ‘real’ world.

The best test that scholars have so far come up with is called the Turing Test, but it examines only social conventions.

The Turing Test is simply a replication of a mundane test every gay man had to undergo in 1950s Britain: can you pass for a straight man? Turing knew from personal experience that it didn’t matter who you really were – it mattered only what others thought about you.

When humans try to determine whether an entity is conscious, what we usually look for is not mathematical aptitude or good memory, but rather the ability to create emotional relationships with us.

Everything a human does – including reporting on allegedly conscious states – might in theory be the work of non-conscious algorithms.

Clever Hans is often given as an example of the way humans erroneously humanise animals, ascribing to them far more amazing abilities than they actually possess. In fact, however, the lesson is just the opposite. The story demonstrates that by humanising animals we usually underestimate animal cognition and ignore the unique abilities of other creatures. As far as maths goes, Hans was hardly a genius. Any eight-year-old kid could do much better. However, in his ability to deduce emotions and intentions from body language, Hans was a true genius.

Humans nowadays completely dominate the planet not because the individual human is far smarter and more nimble-fingered than the individual chimp or wolf, but because Homo sapiens is the only species on earth capable of co-operating flexibly in large numbers. Intelligence and toolmaking were obviously very important as well. But if humans had not learned to cooperate flexibly in large numbers, our crafty brains and deft hands would still be splitting flint stones rather than uranium atoms.

If cooperation is the key, how come the ants and bees did not beat us to the nuclear bomb even though they learned to cooperate en masse millions of years before us? Because their cooperation lacks flexibility. Bees cooperate in very sophisticated ways, but they cannot reinvent their social system overnight. If a hive faces a new threat or a new opportunity, the bees cannot, for example, guillotine the queen and establish a republic.

Social mammals such as elephants and chimpanzees cooperate far more flexibly than bees, but they do so only with small numbers of friends and family members. Their cooperation is based on personal acquaintance. If I am a chimpanzee and you are a chimpanzee and I want to cooperate with you, I must know you personally: what kind of chimp are you? Are you a nice chimp? Are you an evil chimp? How can I cooperate with you if I don’t know you? To the best of our knowledge, only Sapiens can cooperate in very flexible ways with countless numbers of s...

History provides ample evidence for the crucial importance of large-scale cooperation. Victory almost invariably went to those who cooperated better – not only in struggles between Homo sapiens and other animals, but also in conflicts between different human groups. Thus Rome conquered Greece not because the Romans had larger brains or better toolmaking techniques, but because they were able to cooperate more effectively.

In order to mount a revolution, numbers are never enough. Revolutions are usually made by small networks of agitators rather than by the masses. If you want to launch a revolution, don’t ask yourself, ‘How many people support my ideas?’ Instead, ask yourself, ‘How many of my supporters are capable of effective collaboration?’

People are egalitarian by nature, and unequal societies can never function well due to resentment and dissatisfaction. But is that really so?

Why did the Egyptian peasants and Prussian soldiers act so differently than we would have expected on the basis of the Ultimatum Game and the capuchin monkeys experiment? Because large numbers of people behave in a fundamentally different way than do small numbers. What would scientists see if they conducted the Ultimatum Game experiment on two groups of 1 million people each, who had to share $100 billion? They would probably have witnessed strange and fascinating dynamics. For example, since 1 million people cannot make decisions collectively, each group might sprout a small ruling elite. What if one elite offers the other $10 billion, keeping $90 billion? The leaders of the second group might well accept this unfair offer, siphon most of the $10 billion into their Swiss bank accounts, while preventing rebellion among their followers with a combination of sticks and carrots. The leadership might threaten to severely punish dissidents forthwith, while promising the meek and patient everlasting rewards in the afterlife. This is what happened in ancient Egypt and eighteenth-century Prussia, and this is how things still work out in numerous countries around the world.

Most people presume that reality is either objective or subjective, and that there is no third option. Hence once they satisfy themselves that something isn’t just their own subjective feeling, they jump to the conclusion it must be objective.

However, there is a third level of reality: the intersubjective level. Intersubjective entities depend on communication among many humans rather than on the beliefs and feelings of individual humans.

Money, for example, has no objective value.

The value of money is not the only thing that might evaporate once people stop believing in it. The same can happen to laws, gods and even entire empires.

It is relatively easy to accept that money is an intersubjective reality. Most people are also happy to acknowledge that ancient Greek gods, evil empires and the values of alien cultures exist only in the imagination. Yet we don’t want to accept that our God, our nation or our values are mere fictions, because these are the things that give meaning to our lives. We want to believe that our lives have some objective meaning, and that our sacrifices matter to something beyond the stories in our head. Yet in truth the lives of most people have meaning only within the network of stories they tell one another. Meaning is created when many people weave together a common network of stories.

People constantly reinforce each other’s beliefs in a self-perpetuating loop. Each round of mutual confirmation tightens the web of meaning further, until you have little choice but to believe what everyone else believes.

That’s how history unfolds. People weave a web of meaning, believe in it with all their heart, but sooner or later the web unravels, and when we look back we cannot understand how anybody could have taken it seriously.

Sapiens rule the world because only they can weave an intersubjective web of meaning: a web of laws, forces, entities and places that exist purely in their common imagination. This web allows humans alone to organise crusades, socialist revolutions and human rights movements.

Consequently, whereas cats and other animals are confined to the objective realm and use their communication systems merely to describe reality, Sapiens use language to create completely new realities.

Will the chimpanzees, the elephants, the Amazon rainforests and the Arctic glaciers survive the twenty-first century? This depends on the wishes and decisions of intersubjective entities such as the European Union and the World Bank; entities that exist only in our shared imagination.

No other animal can stand up to us, not because they lack a soul or a mind, but because they lack the necessary imagination.

The humanities, in contrast, emphasise the crucial importance of intersubjective entities, which cannot be reduced to hormones and neurons.

North Korea and South Korea are so different from one another not because people in Pyongyang have different genes to people in Seoul, or because the north is colder and more mountainous. It’s because the north is dominated by very different fictions.

Maybe someday breakthroughs in neurobiology will enable us to explain communism and the crusades in strictly biochemical terms. Yet we are very far from that point.

During the twenty-first century the border between history and biology is likely to blur not because we will discover biological explanations for historical events, but rather because ideological fictions will rewrite DNA strands; political and economic interests will redesign the cli...

In the twenty-first century fiction might thereby become the most potent force on earth, surpassing even wayward asteroids and natural selection. Hence if we want to understand our future, cracking genomes and crunching numbers is hardly enough. We must also decipher the fictions that give meaning to the world.

The basic abilities of individual humans have not changed much since the Stone Age. But the web of stories has grown from strength to strength, thereby pushing history from the Stone Age to the Silicon Age.

Animist and polytheist religions depicted the world as the playground of numerous different powers rather than a single god. It was consequently easy for animists and polytheists to accept that many events are unrelated to me or to my favourite deity, and they are neither punishments for my sins nor rewards for my good deeds.

Indeed, even today when US presidents take their oath of office, they put their hand on a Bible. Similarly in many countries around the world, including the USA and the UK, witnesses in courts put their hand on a Bible when swearing to tell the truth, the whole truth and nothing but the truth. It’s ironic that they swear to tell the truth on a book brimming with so many fictions, myths and errors.

Pharaonic Egypt was the most powerful kingdom of its day, but for the simple peasant all that power meant taxes and forced labour rather than clinics and social security services.

Hence when we come to evaluate human cooperation networks, it all depends on the yardsticks and viewpoint we adopt. Are we judging pharaonic Egypt in terms of production, nutrition or perhaps social harmony? Do we focus on the aristocracy, the simple peasants, or the pigs and crocodiles? History isn’t a single narrative,

but thousands of alternative narratives. Whenever we choose to tell one, we are also choosing to silence others.

When examining the history of any human network, it is therefore advisable to stop from time to time and look at things from the perspective of some real entity. How do you know if an entity is real? Very simple – just ask yourself, ‘Can it suffer?’ When people burn down the temple of Zeus, Zeus doesn’t suffer. When the euro loses its value, the euro doesn’t suffer. When a bank goes bankrupt, the bank doesn’t suffer. When a country suffers a defeat in war, the country doesn’t really suffer. It’s just a metaphor. In contrast, when a soldier is wounded in battle, he really does suffer. When a famished peasant has nothing to eat, she suffers. When a cow is separated from her newborn calf, she suffers. This is reality.

In the twenty-first century we will create more powerful fictions and more totalitarian religions than in any previous era. With the help of biotechnology and computer algorithms these religions will not only control our minute-by-minute existence, but will be able to shape our bodies, brains and minds, and to create entire virtual worlds complete with hells and heavens. Being able to distinguish fiction from reality and religion from science will therefore become more difficult but more vital than ever before.

Unfortunately, blind faith in these stories meant that human efforts frequently focused on increasing the glory of fictional entities such as gods and nations, instead of bettering the lives of real sentient beings.

From a historical perspective, the spiritual journey is always tragic, for it is a lonely path fit only for individuals rather than for entire societies.

The traditional view of the world as a pie of a fixed size presupposes that there are only two kinds of resources in the world: raw materials and energy. But in truth there are three kinds of resources: raw materials, energy and knowledge. Raw materials and energy are exhaustible – the more you use, the less you have. Knowledge, in contrast, is a growing resource – the more you use, the more you have. Indeed, when you increase your stock of knowledge, it can give you more raw materials and energy as well. If I invest $100 million searching for oil in Alaska and I find it, then I now have more oil, but my grandchildren will have less of it. In contrast, if I invest $100 million researching solar energy, and I find a new and more efficient way of harnessing it, then both I and my grandchildren will have more energy.

The greatest scientific discovery was the discovery of ignorance.

Once humans realised how little they knew about the world, they suddenly had a very good reason to seek new knowledge, which opened up the scientific road to progress.

We should also be concerned that an ecological apocalypse might have different consequences for different human castes. There is no justice in history. When disaster strikes, the poor almost always suffer far more than the rich, even if the rich caused the tragedy in the first place. Global warming is already affecting the lives of poor people in arid African countries more than the lives of affluent Westerners.

Consider greenhouse gas emissions. Most scholars and an increasing number of politicians recognise the reality of global warming and the magnitude of the danger. Yet this recognition has so far failed to change our actual behavior in any significant way. We talk a lot about global warming, but in practice humankind is unwilling to make the serious economic, social or political sacrifices necessary to stop this catastrophe.