Homo Deus: A Brief History of Tomorrow

by Yuval Noah Harari

For the first time in history, more people die today from eating too much than from eating too little; more people die from old age than from infectious diseases; and more people commit suicide than are killed by soldiers, terrorists and criminals combined. In the early twenty-first century, the average human is far more likely to die from bingeing at McDonald’s than from drought, Ebola or an al-Qaeda attack.

If we are indeed bringing famine, plague and war under control, what will replace them at the top of the human agenda? Like firefighters in a world without fire, so humankind in the twenty-first century needs to ask itself an unprecedented question: what are we going to do with ourselves? In a healthy, prosperous and harmonious world, what will demand our attention and ingenuity?

The following year, 1695, famine struck Estonia, killing a fifth of the population. In 1696 it was the turn of Finland, where a quarter to a third of people died.

Since 1974 hundreds of millions of Chinese have been lifted out of poverty, and though hundreds of millions more still suffer greatly from privation and malnutrition, for the first time in its recorded history China is now free from famine.

Until the early twentieth century, about a third of children died before reaching adulthood from a combination of malnutrition and disease.

In most areas wars became rarer than ever. Whereas in ancient agricultural societies human violence caused about 15 per cent of all deaths, during the twentieth century violence caused only 5 per cent of deaths, and in the early twenty-first century it is responsible for about 1 per cent of global mortality.22 In 2012 about 56 million people died throughout the world; 620,000 of them died due to human violence (war killed 120,000 people, and crime killed another 500,000). In contrast, 800,000 committed suicide, and 1.5 million died of diabetes.23 Sugar is now more dangerous than gunpowder.

The most common reaction of the human mind to achievement is not satisfaction, but craving for more.

In truth, so far modern medicine hasn’t extended our natural life span by a single year. Its great achievement has been to save us from premature death, and allow us to enjoy the full measure of our years.

The upgrading of humans into gods may follow any of three paths: biological engineering, cyborg engineering and the engineering of non-organic beings.

the study of history aims above all to make us aware of possibilities we don’t normally consider.

Each and every one of us has been born into a given historical reality, ruled by particular norms and values, and managed by a unique economic and political system. We take this reality for granted, thinking it is natural, inevitable and immutable. We forget that our world was created by an accidental chain of events, and that history shaped not only our technology, politics and society, but also our thoughts, fears and dreams.

Looking back, many think that the downfall of the pharaohs and the death of God were both positive developments. Maybe the collapse of humanism will also be beneficial. People are usually afraid of change because they fear the unknown. But the single greatest constant of history is that everything changes.

When tectonic movements joined North America with South America it led to the extinction of most South American marsupials, but had no detrimental effect on the Australian kangaroo.

Today more than 90 per cent of all large animals are domesticated.

The Mesopotamian Gilgamesh epic recounts that when the gods sent a great deluge to destroy the world, almost all humans and animals perished. Only then did the rash gods realise that nobody remained to make any offerings to them. They became crazed with hunger and distress. Luckily, one human family survived, thanks to the foresight of the god Enki, who instructed his devotee Utnapishtim to take shelter in a large wooden ark along with his relatives and a menagerie of animals. When the deluge subsided and this Mesopotamian Noah emerged from his ark, the first thing he did was sacrifice some animals to the gods. Then, tells the epic, all the great gods rushed to the spot: ‘The gods smelled the savour / the gods smelled the sweet savour / the gods swarmed like flies around the offering.’27 The biblical story of the deluge (written more than 1,000 years after the Mesopotamian version) also reports that immediately upon leaving the ark, ‘Noah built an altar to the Lord and, taking some of the clean animals and clean birds, he sacrificed burnt offerings on it. The Lord smelled the pleasing aroma and said in his heart: Never again will I curse the ground because of humans’ (Genesis 8:20–1).

Humans thus committed themselves to an ‘agricultural deal’. According to this deal, cosmic forces gave humans command over other animals, on condition that humans fulfilled certain obligations towards the gods, towards nature and towards the animals themselves. It was easy to believe in the existence of such a cosmic compact, because it reflected the daily routine of farming life. Hunter-gatherers had not seen themselves as superior beings because they were seldom aware of their impact on the ecosystem. A typical band numbered in the dozens, it was surrounded by thousands of wild animals, and its survival depended on understanding and respecting the desires of these animals. Foragers had to constantly ask themselves what deer dream about, and what lions think. Otherwise, they could not hunt the deer, nor escape the lions. Farmers, in contrast, lived in a world controlled and shaped by human dreams and thoughts. Humans were still subject to formidable natural forces such as storms and earthquakes, but they were far less dependent on the wishes of other animals. A farm boy learned early on to ride a horse, harness a bull, whip a stubborn donkey and lead the sheep to pasture. It was easy and tempting to believe that such everyday activities reflected either the natural order of things or the will of heaven.

A robot may have an energy sensor that signals to its central processing unit when the battery is about to run out. The robot may then move towards an electrical socket, plug itself in and recharge its battery. However, throughout this process the robot doesn’t experience anything. In contrast, a human being depleted of energy feels hunger and craves to stop this unpleasant sensation. That’s why we say that humans are conscious beings and robots aren’t, and why it is a crime to make people work until they collapse from hunger and exhaustion, whereas making robots work until their batteries run out carries no moral opprobrium.

Scientists don’t know how a collection of electric brain signals creates subjective experiences. Even more crucially, they don’t know what could be the evolutionary benefit of such a phenomenon. It is the greatest lacuna in our understanding of life. Humans have feet, because for millions of generations feet enabled our ancestors to chase rabbits and escape lions. Humans have eyes, because for countless millennia eyes enabled our forebears to see whither the rabbit was heading and whence the lion was coming. But why do humans have subjective experiences of hunger and fear?

level. Intersubjective entities depend on communication among many humans rather than on the beliefs and feelings of individual humans.

No matter how mistaken the biblical world view was, it provided a better basis for large-scale human cooperation. 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.

Fictions enable us to cooperate better. The price we pay is that the same fictions also determine the goals of our cooperation.

Religion is any all-encompassing story that confers superhuman legitimacy on human laws, norms and values. It legitimises human social structures by arguing that they reflect superhuman laws.

Religion asserts that we humans are subject to a system of moral laws that we did not invent and that we cannot change.

Religion is a deal, whereas spirituality is a journey.

Religion gives a complete description of the world, and offers us a well-defined contract with predetermined goals. ‘God exists. He told us to behave in certain ways. If you obey God, you’ll be admitted to heaven. If you disobey Him, you’ll burn in hell.’ The very clarity of this deal allows society to define common norms and values that regulate human behaviour. Spiritual journeys are nothing like that. They usually take people in mysterious ways towards unknown destinations. The quest usually begins with some big question, such as who am I?

Yet in fact modernity is a surprisingly simple deal. The entire contract can be summarised in a single phrase: humans agree to give up meaning in exchange for power.

Since there is no script, and since humans fulfil no role in any great drama, terrible things might befall us and no power will come to save us or give meaning to our suffering. There won’t be a happy ending, or a bad ending, or any ending at all. Things just happen, one after the other. The modern world does not believe in purpose, only in cause. If modernity has a motto, it is ‘shit happens’.

On the other hand, if shit just happens, without any binding script or purpose, then humans too are not confined to any predetermined role. We can do anything we want – provided we can find a way. We are constrained by nothing except our own ignorance.

The modern deal thus offers humans an enormous temptation, coupled with a colossal threat. Omnipotence is in front of us, almost within our reach, but below us yawns the abyss of complete nothingness.

This escape clause has been the salvation of modern society, for it is impossible to sustain order without meaning. The great political, artistic and religious project of modernity has been to find a meaning to life that is not rooted in some great cosmic plan. We are not actors in a divine drama, and nobody cares about us and our deeds, so nobody sets limits to our power – but we are still convinced our lives have meaning.

At the end of their journey they discover that the great wizard is a charlatan, and he can’t give them any of these things. But they discover something far more important: everything they wished for was already within themselves. There was never any need of some godlike wizard in order to become sensitive, wise or brave. You just need to follow the yellow brick road and open yourself up to whatever experiences come your way.

Hundreds of millions clung to the religious dogmas of Hong, Dayananda, Pius and the Mahdi even as industrial factories, railroads and steamships filled the world. Yet most of us don’t think about the nineteenth century as the age of faith.

The humanist belief in feelings has enabled us to benefit from the fruits of the modern covenant without paying its price. We don’t need any gods to limit our power and give us meaning – the free choices of customers and voters supply us with all the meaning we require. What, then, will happen once we realise that customers and voters never make free choices, and once we have the technology to calculate, design or outsmart their feelings? If the whole universe is pegged to the human experience, what will happen once the human experience becomes just another designable product,

Today we can use brain scanners to predict people’s desires and decisions well before they are aware of them. In one such experiment people are placed within a huge brain scanner, holding a switch in each hand. They are asked to press one of the two switches whenever they feel like it. Scientists observing neural activity in the brain can predict which switch the person will press well before the person actually does so, and even before the person is aware of their own intention. Neural events in the brain indicating the person’s decision begin from a few hundred milliseconds to a few seconds before the person is aware of this choice.2

Animal-welfare activists have voiced concern about the suffering such experiments inflict on the rats. Professor Sanjiv Talwar of the State University of New York, one of the leading robo-rat researchers, has dismissed these concerns, arguing that the rats actually enjoy the experiments. After all, explains Talwar, the rats ‘work for pleasure’ and when the electrodes stimulate the reward centres in their brains, ‘the rat feels Nirvana’.3 To the best of our understanding, the rat doesn’t feel that somebody else controls her, and she doesn’t feel that she is being coerced to do anything against her will. When Professor Talwar presses the remote control, the rat wants to move to the left, which is why she moves to the left. When the professor presses another switch, the rat wants to climb a ladder, which is why she climbs the ladder. After all, the rat’s desires are nothing but a pattern of firing neurons.

Sally Adee, a journalist for the New Scientist, was allowed to visit a training facility for snipers and test the effects herself. At first she entered a battlefield simulator without wearing the transcranial helmet. Sally describes how fear swept over her as twenty masked men, strapped with suicide bombs and armed with rifles, charge straight towards her. ‘For every one I manage to shoot dead,’ writes Sally, ‘three new assailants pop up from nowhere. I’m clearly not shooting fast enough, and panic and incompetence are making me continually jam my rifle.’ Luckily for her, the assailants were just video images projected on huge screens all around her. Still, she was so disappointed with her poor performance that she felt like ditching the rifle and leaving the simulator. Then they wired her up to the helmet. She reports feeling nothing unusual, except a slight tingle and a strange metallic taste in her mouth. Yet she began picking off the virtual terrorists one by one, as coolly and methodically as if she were Rambo or Clint Eastwood. ‘As twenty of them run at me brandishing their guns, I calmly line up my rifle, take a moment to breathe deeply, and pick off the closest one, before tranquilly assessing my next target. In what seems like next to no time, I hear a voice call out, “Okay, that’s it.” The lights come up in the simulation room . . . In the sudden quiet amid the bodies around me, I was really expecting more assailants, and I’m a bit disappointed when the team begi...

But in the twenty-first century this is becoming an urgent political and economic issue. And it is sobering to realise that, at least for armies and corporations, the answer is straightforward: intelligence is mandatory but consciousness is optional.

Armies and corporations cannot function without intelligent agents, but they don’t need consciousness and subjective experiences.

on 6 May 2010, the New York stock exchange underwent an even sharper shock. Within five minutes – from 14:42 to 14:47 – the Dow Jones dropped by 1,000 points, wiping out $1 trillion. It then bounced back, returning to its pre-crash level in a little more than three minutes. That’s what happens when super-fast computer programs are in charge of our money. Experts have been trying ever since to understand what happened in this so-called ‘Flash Crash’. They know algorithms were to blame, but are still not sure exactly what went wrong.

Since we do not know how the job market would look in 2030 or 2040, already today we have no idea what to teach our kids. Most of what they currently learn at school will probably be irrelevant by the time they are forty. Traditionally, life has been divided into two main parts: a period of learning followed by a period of working. Very soon this traditional model will become utterly obsolete, and the only way for humans to stay in the game will be to keep learning throughout their lives, and to reinvent themselves repeatedly. Many if not most humans may be unable to do so.

In the twenty-first century our personal data is probably the most valuable resource most humans still have to offer, and we are giving it to the tech giants in exchange for email services and funny cat videos.

As we have seen, humans are not individuals, and they don’t have a single unified self. Whose interests, then, should Cortana serve? Suppose my narrating self makes a New Year resolution to start a diet and go to the gym every day. A week later, when it is time for the gym, the experiencing self instructs Cortana to turn on the TV and order pizza. What should Cortana do? Should it obey the experiencing self, or the resolution taken a week earlier by the narrating self?

As of early 2016, the sixty-two richest people in the world were worth as much as the poorest 3.6 billion people! Since the world’s population is about 7.2 billion, it means that these sixty-two billionaires together hold as much wealth as the entire bottom half of humankind.

The great human projects of the twentieth century – overcoming famine, plague and war – aimed to safeguard a universal norm of abundance, health and peace for everyone without exception. The new projects of the twenty-first century – gaining immortality, bliss and divinity – also hope to serve the whole of humankind. However, because these projects aim at surpassing rather than safeguarding the norm, they may well result in the creation of a new superhuman caste that will abandon its liberal roots and treat normal humans no better than nineteenth-century Europeans treated Africans.

the most interesting place in the world from a religious perspective is not the Islamic State or the Bible Belt, but Silicon Valley. That’s where hi-tech gurus are brewing for us brave new religions that have little to do with God, and everything to do with technology. They promise all the old prizes – happiness, peace, prosperity and even eternal life – but here on earth with the help of technology, rather than after death with the help of celestial beings.

These new techno-religions can be divided into two main types: techno-humanism and data religion. Data religion argues that humans have completed their cosmic task and should now pass the torch on to entirely new kinds of entities. We will discuss the dreams and nightmares of data religion in the next chapter. This chapter is dedicated to the more conservative creed of techno-humanism, which still sees humans as the apex of creation and clings to many traditional humanist values. Techno-humanism agrees that Homo sapiens as we know it has run its historical course and will no longer be relevant in the future, but concludes that we should therefore use technology in order to create Homo deus – a much superior human model.

However, whereas Hitler and his ilk planned to create superhumans by means of selective breeding and ethnic cleansing, twenty-first-century techno-humanism hopes to reach that goal far more peacefully, with the help of genetic engineering, nanotechnology and brain–computer interfaces.

However, most scientific research about the human mind and the human experience has been conducted on people from Western, educated, industrialised, rich and democratic (WEIRD) societies, who do not constitute a representative sample of humanity. The study of the human mind has so far assumed that Homo sapiens is Homer Simpson. In a groundbreaking 2010 study, Joseph Henrich, Steven J. Heine and Ara Norenzayan systematically surveyed all the papers published between 2003 and 2007 in leading scientific journals belonging to six different subfields of psychology. They found that though the papers often made broad claims about the human mind, most of them based their findings on exclusively WEIRD samples.

When we mix a practical ability to engineer minds with our ignorance of the mental spectrum and with the narrow interests of governments, armies and corporations, we get a recipe for trouble. We may successfully upgrade our bodies and our brains, while losing our minds in the process. Indeed, techno-humanism may end up downgrading humans.