Homo Deus: A Brief History of Tomorrow

by Yuval Noah Harari

Thus the Old Testament God never promises any rewards or punishments after death. He instead tells the people of Israel that ‘If you carefully observe the commands that I’m giving you [. . .] then I will send rain on the land in its season [. . .] and you’ll gather grain, wine, and oil. I will provide grass in the fields for your livestock, and you’ll eat and be satisfied. Be careful! Otherwise, your hearts will deceive you and you will turn away to serve other gods and worship them. The wrath of God will burn against you so that he will restrain the heavens and it won’t rain. The ground won’t yield its produce and you’ll be swiftly destroyed from the good land that the Lord is about to give you’ (Deuteronomy 11:13–17).

A friend once told me that what she fears most about growing old is becoming irrelevant, turning into a nostalgic old woman who cannot understand the world around her, or contribute much to it. This is what we fear collectively, as a species, when we hear of superhumans.

Since no one understands the system any more, no one can stop it.

Viagra began life as a treatment for blood-pressure problems. To the surprise and delight of Pfizer, it transpired that Viagra can also overcome impotence. It enabled millions of men to regain normal sexual abilities; but soon enough men who had no impotence problems in the first place began using the same pill to surpass the norm, and acquire sexual powers they never had before.

Modern plastic surgery was born in the First World War, when Harold Gillies began treating facial injuries in the Aldershot military hospital.46 When the war was over, surgeons discovered that the same techniques could also turn perfectly healthy but ugly noses into more beautiful specimens. Though plastic surgery continued to help the sick and wounded, it devoted increasing attention to upgrading the healthy. Nowadays plastic surgeons make millions in private clinics whose explicit and sole aim is to upgrade the healthy and beautify the wealthy.

(A famous – and probably apocryphal – anecdote tells of a meeting in 1923 between Nobel Prize laureate Anatole France and the beautiful and talented dancer Isadora Duncan. Discussing the then popular eugenics movement, Duncan said, ‘Just imagine a child with my beauty and your brains!’ France responded, ‘Yes, but imagine a child with my beauty and your brains.’)

In 2000 Sharon Saarinen from West Bloomfield, Michigan, gave birth to a healthy baby girl, Alana. Alana’s nuclear DNA came from her mother, Sharon, and her father, Paul, but her mitochondrial DNA came from another woman. From a purely technical perspective, Alana has three biological parents. A year later, in 2001, the US government banned this treatment, due to safety and ethical concerns.

However, on 3 February 2015 the British Parliament voted in favour of the so-called ‘three-parent embryo’ law, allowing this treatment – and related research – in the UK.

But history doesn’t work like that. Those living in palaces have always had different agendas to those living in shacks, and that is unlikely to change in the twenty-first century.

This is the paradox of historical knowledge. Knowledge that does not change behaviour is useless. But knowledge that changes behaviour quickly loses its relevance. The more data we have and the better we understand history, the faster history alters its course, and the faster our knowledge becomes outdated.

Movements seeking to change the world often begin by rewriting history, thereby enabling people to reimagine the future. Whether you want workers to go on a general strike, women to take possession of their bodies, or oppressed minorities to demand political rights – the first step is to retell their history. The new history will explain that ‘our present situation is neither natural nor eternal. Things were different once. Only a string of chance events created the unjust world we know today. If we act wisely, we can change that world, and create a much better one.’

In my former Oxford college the entire quad was formed of a large, attractive lawn, on which we were allowed to walk or sit on only one day a year. On any other day, woe to the poor student whose foot desecrated the holy turf.

For thousands of years humans played on almost every conceivable kind of ground, from ice to desert. Yet in the last two centuries, the really important games – such as football and tennis – are played on lawns.

After Sunday morning service at church, many people devotedly mowed their lawns. Walking along the streets, you could quickly ascertain the wealth and position of every family by the size and quality of their turf.

Qatar’s newly built Museum of Islamic Art is flanked by magnificent lawns that hark back to Louis XIV’s Versailles much more than to Haroun al-Rashid’s Baghdad. They were designed and constructed by an American company, and their more than 100,000 square yards of grass – in the midst of the Arabian desert – require a stupendous amount of fresh water each day to stay green.

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.

If you start with a flawed ideal, you often appreciate its defects only when the ideal is close to realisation.

We can already see this process at work in geriatric hospital wards. Due to an uncompromising humanist belief in the sanctity of human life, we keep people alive till they reach such a pitiful state that we are forced to ask, ‘What exactly is so sacred here?’

No investigation of our divine future can ignore our own animal past, or our relations with other animals – because the relationship between humans and animals is the best model we have for future relations between superhumans and humans.

With regard to other animals, humans have long since become gods. We don’t like to reflect on this too deeply, because we have not been particularly just or merciful gods.

Since 1970, despite growing ecological awareness, wildlife populations have halved (not that they were prospering in 1970).

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.

Some people fear that today we are again in mortal danger of massive volcanic eruptions or colliding asteroids. Hollywood producers make billions out of these anxieties. Yet in reality, the danger is slim. Mass extinctions occur once every many millions of years. Yes, a big asteroid will probably hit our planet sometime in the next 100 million years, but it is very unlikely to happen next Tuesday. Instead of fearing asteroids, we should fear ourselves.

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.

When the last ice age reached its peak 20,000 years ago, jellyfish in the Persian Gulf and jellyfish in Tokyo Bay both had to adapt to the new climate. Yet since there was no connection between the two populations, each reacted in a different way, evolving in distinct directions.

But the Anthropocene isn’t a novel phenomenon of the last few centuries. Already tens of thousands of years ago, when our Stone Age ancestors spread from East Africa to the four corners of the earth, they changed the flora and fauna of every continent and island on which they settled.

They drove to extinction all the other human species of the world, 90 per cent of the large animals of Australia, 75 per cent of the large mammals of America and about 50 per cent of all the large land mammals of the planet – and all before they planted the first wheat field, shaped the first metal tool, wrote the first text or struck the first coin.

The advent of farming produced new waves of mass extinctions, but more importantly, it created a completely new life form on earth: domesticated animals. Initially this development was of minor importance, since humans managed to domesticate fewer than twenty species of mammals and birds, compared to the countless thousands of species that remained ‘wild’. Yet with the passing of the centuries, this novel life form became dominant. Today more than 90 per cent of all large animals are domesticated.

domesticated species paid for their unparalleled collective success with unprecedented individual suffering.

Two competing factors have shaped the living conditions of farm animals from ancient times to the present day: human desires and animal needs.

Of course evolution never stands still, and it has continued to modify humans and animals in the 12,000 years since the advent of farming. For example, humans in Europe and western Asia evolved the ability to digest cows’ milk, while cows lost their fear of humans, and today produce far more milk than their wild ancestors.

Why do young men drive recklessly, get involved in violent arguments and hack confidential Internet sites? Because they are following ancient genetic decrees that might be useless and even counterproductive today, but that made good evolutionary sense 70,000 years ago. A young hunter who risked his life chasing a mammoth outshone all his competitors and won the hand of the local beauty, and we are now stuck with his macho genes.

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.

An algorithm is a methodical set of steps that can be used to make calculations, resolve problems and reach decisions.

How exactly does a baboon calculate probabilities? He certainly doesn’t draw a pencil from behind his ear, a notebook from a back pocket, and start computing running speeds and energy levels with a calculator. Rather, the baboon’s entire body is the calculator. What we call sensations and emotions are in fact algorithms.

Natural selection evolved passion and disgust as quick algorithms for evaluating reproduction odds.

The theology, mythology and liturgy of religions such as Judaism, Hinduism and Christianity revolved at first around the relationship between humans, domesticated plants and farm animals.

Theist religions, such as biblical Judaism, justified the agricultural economy through new cosmological myths.

The gods safeguarded and multiplied farm production, and in exchange humans had to share the produce with the gods. This deal served both parties, at the expense of the rest of the ecosystem.

Today in Nepal, devotees of the goddess Gadhimai celebrate her festival every five years in the village of Bariyapur. A record was set in 2009 when 250,000 animals were sacrificed to the goddess. A local driver explained to a visiting British journalist that ‘If we want anything, and we come here with an offering to the goddess, within five years all our dreams will be fulfilled.’

After all, when ‘the Lord saw how great the wickedness of the human race had become’ He resolved to ‘wipe from the face of the earth the human race I have created – and with them the animals, the birds and the creatures that move along the ground – for I regret that I have made them’ (Genesis 6:7).

Hinduism, for example, has sanctified cows and forbidden eating beef, but has also provided the ultimate justification for the dairy industry, alleging that cows are generous creatures that positively yearn to share their milk with humankind.

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.

The Agricultural Revolution was thus both an economic and a religious revolution. New kinds of economic relations emerged together with new kinds of religious beliefs that justified the brutal exploitation of animals.

In the Nayaka language a living being possessing a unique personality is called mansan.

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. The founding idea of humanist religions such as liberalism, communism and Nazism is that Homo sapiens has some unique and sacred essence that is the source of all meaning and authority in the universe. Everything that happens in the cosmos is judged to be good or bad according to its impact on Homo sapiens.

There is no doubt that Homo sapiens is the most powerful species in the world. Homo sapiens also likes to think that it enjoys a superior moral status, and that human life has much greater value than the lives of pigs, elephants or wolves. This is less obvious. Does might make right?

There is zero scientific evidence that in contrast to pigs, Sapiens have souls.

the theory of relativity and quantum mechanics argue that you can twist time and space, that something can appear out of nothing, and that a cat can be both alive and dead at the same time. This makes a mockery of our common sense, yet nobody seeks to protect innocent schoolchildren from these scandalous ideas. Why?