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.

Anton Chekhov famously said that a gun appearing in the first act of a play will inevitably be fired in the third. Throughout history, if kings and emperors acquired some new weapon, sooner or later they were tempted to use it. Since 1945, however, humankind has learned to resist this temptation. The gun that appeared in the first act of the Cold War was never fired. By now we are accustomed to living in a world full of undropped bombs and unlaunched missiles, and have become experts in breaking both the Law of the Jungle and the Chekhov Law. If these laws ever do catch up with us, it will be our own fault – not our inescapable destiny.

Yet appreciating the magnitude of our achievements carries another message: history does not tolerate a vacuum. If incidences of famine, plague and war are decreasing, something is bound to take their place on the human agenda.

Having reduced mortality from starvation, disease and violence, we will now aim to overcome old age and even death itself. Having saved people from abject misery, we will now aim to make them positively happy. And having raised humanity above the beastly level of survival struggles, we will now aim to upgrade humans into gods, and turn Homo sapiens into Homo deus.

In a famous experiment scientists connected electrodes to the brains of several rats, enabling the animals to create sensations of excitement simply by pressing a pedal. When the rats were given a choice between tasty food and pressing the pedal, they preferred the pedal

Though historians occasionally try their hand at prophecy (without notable success), the study of history aims above all to make us aware of possibilities we don’t normally consider. Historians study the past not in order to repeat it, but in order to be liberated from it.

This is the best reason to learn history: not in order to predict the future, but to free yourself of the past and imagine alternative destinies. Of course this is not total freedom – we cannot avoid being shaped by the past. But some freedom is better than none.

At present, more than 90 per cent of the large animals of the world (i.e., those weighing more than a few pounds) are either humans or domesticated animals.

A Nayaka was once killed by a male elephant they called ‘the elephant who always walks alone’. The Nayakas refused to help officials from the Indian forestry department capture him. They explained to Naveh that this elephant used to be very close to another male elephant, with whom he always roamed. One day the forestry department captured the second elephant, and since then ‘the elephant who always walks alone’ had become angry and violent. ‘How would you have felt if your spouse had been taken away from you? This is exactly how this elephant felt. These two elephants sometimes separated at night, each walking its own path . . . but in the morning they always came together again. On that day, the elephant saw his buddy falling, lying down. If two are always together and then you shoot one – how would the other feel?’8

In the Garden of Eden, Adam and Eve lived as foragers. The expulsion from Eden bears a striking resemblance to the Agricultural Revolution. Instead of allowing Adam to keep gathering wild fruits, an angry God condemns him ‘to eat bread by the sweat of your brow’. It

despair.15 This is the basic lesson of evolutionary psychology: a need shaped thousands of generations ago continues to be felt subjectively even if it is no longer necessary for survival and reproduction in the present. Tragically, the Agricultural Revolution gave humans the power to ensure the survival and reproduction of domesticated animals while ignoring their subjective needs.

More broadly, scientists know that if an electric storm arises in a given brain area, you probably feel angry. If this storm subsides and a different area lights up – you are experiencing love. Indeed, scientists can even induce feelings of anger or love by electrically stimulating the right neurons. But how on earth does the movement of electrons from one place to the other translate into a subjective image of Bill Clinton, or a subjective feeling of anger or love?

When thousands of cars slowly edge their way through London, we call that a traffic jam, but it doesn’t create some great Londonian consciousness that hovers high above Piccadilly and says to itself, ‘Blimey, I feel jammed!’ When millions of people sell billions of shares, we call that an economic crisis, but no great Wall Street spirit grumbles, ‘Shit, I feel I am in crisis.’ When trillions of water molecules coalesce in the sky we call that a cloud, but no cloud consciousness emerges to announce, ‘I feel rainy.’ How is it, then, that when billions of electric signals move around in my brain, a mind emerges that feels ‘I am furious!’? As of 2016, we have absolutely no idea.

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.

Just as in present-day San Francisco John is employed by Google while Mary works for Microsoft, so in ancient Uruk one person was employed by the great god Enki while his neighbour worked for the goddess Inanna. The temples of Enki and Inanna dominated the Uruk skyline, and their divine logos branded buildings, products and clothes. For the Sumerians, Enki and Inanna were as real as Google and Microsoft are real for us.

If the Sumerian gods remind us of present-day company brands, so the living-god pharaoh can be compared to modern personal brands such as Elvis Presley, Madonna or Justin Bieber.

Pharaoh himself hardly lifted a finger, of course. He didn’t collect taxes himself, he didn’t draw any architectural plans, and he certainly never picked up a shovel. But the Egyptians believed that only prayers to the living-god pharaoh and to his heavenly patron Sobek could save the Nile Valley from devastating floods and droughts. They were right.

If you want to make people believe in imaginary entities such as gods and nations, you should make them sacrifice something valuable. The more painful the sacrifice, the more convinced they will be of the existence of the imaginary recipient.

Organisms are algorithms. Every animal – including Homo sapiens – is an assemblage of organic algorithms shaped by natural selection over millions of years of evolution. 2. Algorithmic calculations are not affected by the materials from which the calculator is built. Whether an abacus is made of wood, iron or plastic, two beads plus two beads equals four beads. 3. Hence there is no reason to think that organic algorithms can do things that non-organic algorithms will never be able to replicate or surpass. As long as the calculations remain valid, what does it matter whether the algorithms are manifested in carbon or silicon?

In the heyday of European imperialism, conquistadors and merchants bought entire islands and countries in exchange for coloured beads. 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.

Already today many of us give up our privacy and our individuality by conducting much of our lives online, recording our every action and becoming hysterical if connection to the net is interrupted even for a few minutes. The shifting of authority from humans to algorithms is happening all around us, not as a result of some momentous governmental decision, but due to a flood of mundane personal choices.

In the past, censorship worked by blocking the flow of information. In the twenty-first century censorship works by flooding people with irrelevant information.