Yuval Noah Harari
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Homo Deus is almost a religion book. It analyzes past religions, how we ended up with current ones, and possibilities for future ones: what the future religions may look like, what their impact may be, and – implicitly – what their odds are.

This quote from the opening beautifully summarizes what’s to come:

“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? This question becomes doubly urgent given the immense new powers that biotechnology and information technology are providing us with. What will we do with all that power?”

The book is somehow both optimistic and incredibly pessimistic. Humans will succeed in all endeavors, but their success will render them useless and obsolete and will ultimately lead to their destruction.

Also: check out this episode of Made You Think, where I join Nat and Neil to discuss Sapiens and Homo Deus.


For millennia, humans were concerned with three things: (1) famine, (2) plague, and (3) war. Now, for the first time ever, these are no longer the major killers of Homo sapiens.

Now: more people die from too much food than too little. Infectious disease is not nearly as rampant. More suicides than deaths in war.

Major takeaway: famine still occurs, but natural famine does not. Only when politics fails us do people starve. Natural famine has been eradicated.

Overeating is a bigger problem than under-eating – this is a historical first. In 2010, 1 million people died of famine and malnutrition – but 3 million died of obesity.

Plagues are all but gone too. Science can outpace epidemics. Although antibiotics and other medications are developing resistance to common medications, they rely on random mutations in order to be particularly deadly. Scientists, on the other hand, are methodical and do not rely on randomness in order to craft medications. New epidemics will emerge… but science is ahead.

The definition of ‘peace’ has changed with time. Before, it meant that two nations were not currently at war. They might have been at war last year or might realistically be at war next year – but if they were currently not at war, it was called peace. Today, peace means that war is unfathomable between those parties.

“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.”

Peace is now more profitable than war. Enemies can make more money cooperating with high-tech companies than they can invading another country.

The first new human project: Immortality

Our great power has allowed us to end war, famine, and plaque, but it has also resulted in massive ecological damage. Yet, every time politicians choose between ecological stability and economic growth, they pick growth. There’s two lessons to be learned here: (1) our greatest threat to ourselves is ourselves; much like how we must be responsible with nukes, we must be responsible with our other great power as well; (2) politics is what is failing us again and again – famine, war, plague only happen when government fails, and the same goes for our failure against new threats such as global warming.

Without other problems to solve, Sapiens will target a new enemy: death. Immortality will be the new project for humanity, followed by happiness and divinity.

Why will our next target be to eliminate death?

“The Universal Declaration of Human Rights adopted by the UN after the Second World War –which is perhaps the closest thing we have to a global constitution –categorically states that ‘the right to life’ is humanity’s most fundamental value. Since death clearly violates this right, death is a crime against humanity, and we ought to wage total war against it.“

As rosy as beating death may seem, Harari points out there are several complications.

First, we won’t be immortal – at least not in the short run. First, we must become amortal, meaning that we won’t die of natural causes – but if we get hit by a bus, we may. This will make people incredibly risk-averse. If an activity poses even a minor risk, why engage in it when immortality is on the line?

Second, when everybody lives extremely long lives, a number of social structures we have in place will have to adapt. What happens to marriage if your life expectancy is 150? You can’t reasonably expect to marry at 30 and stay together for 120 years. What about your career? You probably won’t retire until 130. Your current boss may be your boss for another decade.

Another interesting observation pertaining to human life: scientists have yet to actually extend human life. They’ve merely discovered ways to prevent its premature end.

Second human project? Happiness

“At the end of the eighteenth century the British philosopher Jeremy Bentham declared that the supreme good is ‘the greatest happiness of the greatest number’, and concluded that the sole worthy aim of the state, the market and the scientific community is to increase global happiness.“

But no one actually did it. Instead, they focused on immediate aims, like a military and government work. Projects that increased happiness as a second-order effect were good, but primary aim was keeping people alive and serving the country.

Happiness always resumes a baseline. No matter how much better life gets – new appliances, conveniences, perks – happiness always resumes a baseline.

Two reasons: one psychological and one biological.

First reason: psychological reason. Happiness depends on expectations, not objective conditions. As conditions improve, expectations balloon, which leads to stagnant (or decreasing) happiness.

Second reason: biological. Happiness is determined by biochemistry. Happiness and suffering are merely different balances of bodily sensations.

“What might have happened if a rare mutation had created a squirrel who, after eating a single nut, enjoys an everlasting sensation of bliss?”

It would die! Hence why we must resume to a baseline.

Third human project: Divinity

The third major project (after eradicating death and finding happiness) will be upgrading human king from Homo Sapiens into Homo Deus. Giving us the powers of creation and destruction.

Eventually, we’ll be “upgrading” ourselves and our kids with medications, genetic alterations, and more. It won’t be robotic and dystopian as it sounds, either – it’ll creep up on you slowly, either due to societal pressure or goodwill.

“In 2011, 3.5 million American children were taking medications for ADHD (attention deficit hyperactivity disorder). In the UK the number rose from 92,000 in 1997 to 786,000 in 2012.38 The original aim had been to treat attention disorders, but today completely healthy kids take such medications to improve their performance and live up to the growing expectations of teachers and parents.”

A new challenge: when you upgrade humans, you change their minds. So it thus becomes impossible to predict how people will use new technologies, since the people will be unlike anyone alive today.

In many ways, we already have the power of destruction – nukes.

“Well, if we need endless projects, why not settle for bliss and immortality, and at least put aside the frightening quest for superhuman powers? Because it is inextricable from the other two. When you develop bionic legs that enable paraplegics to walk again, you can also use the same technology to upgrade healthy people. When you discover how to stop memory loss among older people, the same treatments might enhance the memory of the young.”

Examples: (1) viagra used to be blood pressure medicine; (2) plastic surgery used to be for repairing disfigured faces in WWI.

One of my favorite quotes from the whole book:

“Homo sapiens is likely to upgrade itself step by step, merging with robots and computers in the process, until our descendants will look back and realise that they are no longer the kind of animal that wrote the Bible, built the Great Wall of China and laughed at Charlie Chaplin’s antics. This will not happen in a day, or a year. Indeed, it is already happening right now, through innumerable mundane actions. Every day millions of people decide to grant their smartphone a bit more control over their lives or try a new and more effective antidepressant drug. In pursuit of health, happiness and power, humans will gradually change first one of their features and then another, and another, until they will no longer be human.”

This is impossible to stop. Nobody knows how – the fields in which we are progressing are far too many and far too complex. And capitalism begs us to do it—a longer lifespan means more spending! The growth must continue.

Opening chapter has been about where our past ideals will take us in the near future. The remainder of the book is about what comes after we achieve divinity and have new ideals. Where will our new ideals take us?

Part 1: Homo Sapiens Conquers the World

This section is largely a rehash of Sapiens.

Most of the world is populated not by the animals you see on National Geographic, but by humans and their domesticated animal friends.

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

Another major shift: until now, all change was through an evolutionary approach. But now? We have intelligent design – and ‘intelligent’ may be far too self-congratulatory, for all it means is “human design”.

Evidence points to ancient hunter-gatherer being animists. Animists believe themselves as equals to animals – so in cases, such as the Nayaka people, where a person was killed by an animal, the tribe will side with the animal, even if a modern society intervenes and attempts to capture the ‘criminal’ animal.

Increasing amounts of evidence indicate that emotions are not unique to humans. Many mammals, as well as some reptiles and fish, all feel emotion. They are essential to survival.

This is not your typical type of “emotion”. Harari’s example: a baboon is looking at some bananas on a tree, and notices a lion nearby. Different forces come into play: fear of the lion, want of the bananas (related to hunger). Does courage beat hunger here? Making the right calculation will determine whether the baboon lives or dies.

Ha – Harari’s example of a man well-suited for reproduction is George Clooney. Nice way to be immortalized in a book.

“Only in the 1950s and 1960s did a growing consensus of experts abandon these strict behaviourist theories and acknowledge the central importance of emotional needs. In a series of famous (and shockingly cruel) experiments, the psychologist Harry Harlow separated infant monkeys from their mothers shortly after birth, and isolated them in small cages. When given a choice between a metal dummy-mother fitted with a milk bottle, and a soft cloth-covered dummy with no milk, the baby monkeys clung to the barren cloth mother for all they were worth.

Those baby monkeys knew something that John Watson and the experts of Infant Care failed to realise: mammals can’t live on food alone. They need emotional bonds too. Millions of years of evolution preprogrammed the monkeys with an overwhelming desire for emotional bonding. Evolution also imprinted them with the assumption that emotional bonds are more likely to be formed with soft furry things than with hard and metallic objects.”

Aside: its obviously good that we don’t do this kind of shockingly cruel experimentation anymore. Though I wonder what kind of potential findings might go undiscovered because of it? I’d be curious to see studies rejected by IRB for cruelty, though I doubt that scratches the surface, since many won’t submit such ideas.

Ancient animist religions: humans and animals are equal. Theist religions changed that – humans are special, only humans have souls, everything revolves around us – and thus allowed humans to milk animals and the earth for what its worth. We’ve now done terrible things to the earth and to other animals.

“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? Is human life more precious than porcine life simply because the human collective is more powerful than the pig collective? The United States is far mightier than Afghanistan; does this imply that American lives have greater intrinsic value than Afghan lives?”

The Self

Self-consciousness is a common argument to defend why humans are special and “better” (more valuable? sacred?) than other species. But there’s no way to prove that other animals don’t have self-consciousness. In fact, there’s no way for any of us to prove that anyone but ourselves has consciousness.

Is consciousness an emergent property? How did consciousness evolve? Is it like the soul, all or nothing? Or was it gradual? How would we even know?

Coordinating Large Groups

Thesis of Sapiens and main idea in this chapter: our success as a species is owed not to bigger brains or strong bodies (and there’s no evidence to indicate either has happened), but rather to our ability to cooperate flexibly in large groups.

Survival and dominance is not just about coordinating large groups (bees, ants) or cooperating flexibly (chimpanzees), it’s about having both properties: coordinating large groups flexibly. That is unique to Sapiens. And in Sapien-to-Sapien conflicts, the more flexible and larger the group, the more likely they are to win.

Ideas and Myths

Intersubjective reality: a shared reality (shared myths) like money, systems of governance, companies, etc.

“Many of the most important agents in history are intersubjective. Money, for example, has no objective value. You cannot eat, drink or wear a dollar bill. Yet as long as billions of people believe in its value, you can use it to buy food, beverages and clothing. If the baker suddenly loses his faith in the dollar bill and refuses to give me a loaf of bread for this green piece of paper, it doesn’t matter much. I can just go down a few blocks to the nearby supermarket. However, if the supermarket cashiers also refuse to accept this piece of paper, along with the hawkers in the market and the salespeople in the mall, then the dollar will lose its value. The green pieces of paper will go on existing, of course, but they will be worthless.”

Part 2: Homo Sapiens Gives Meaning to the World

Other species have two realities: objective and subjective. Sapiens has three: objective, subjective, and inter-subjective (shared myths and ideas).

Writing versus reality. When should reality give in to writing when they conflict? Example from book: African borders drawn by European powers. They made no sense – but reality gave in. Another example: schools and grades (“marks”). Grades used to be a way to measure progress learning, with learning being the priority. Now grades are the priority – and do not necessarily correlate to learning.

Religion and Science

Religion is closer to science than it is to spirituality. Religion is rules; if you do this, heaven; if you do that, hell. But spirituality is a journey, an exploration.

“Religions seek to cement the world order whereas spirituality seeks to escape it.”

Religion and science need to cooperate to a degree. They aren’t sworn enemies and opposites. Example: the three gorges dam in China would kill endangered species and displace a million locals. Science can tell us how to build the dam; but a religion or ideology is necessary to answer the ethical questions.

Or abortion. Everyone agrees life is sacred and murder is bad. But we need science to tell us when life begins.

We always hear about the clash between religion and science. Despite that, they have the same goal: they are interested in discovering the truth about the universe.

The Modern Covenant

The power/meaning tradeoff: in the past, you had no power but had meaning. If a plague hit, you couldn’t do anything about it, but it was part of God’s plan and your life meant something. Today, your life means nothing and God has no plan – but you have power the in ways you didn’t before.

““If we invest money in research, then scientific breakthroughs will accelerate technological progress. New technologies will fuel economic growth, and a growing economy will dedicate even more money to research. With each passing decade we will enjoy more food, faster vehicles and better medicines. One day our knowledge will be so vast and our technology so advanced that we shall distill the elixir of eternal youth, the elixir of true happiness, and any other drug we might possibly desire –and no god will stop us.”

Economic growth is the supreme value that everyone can agree on: Christians and Atheists, Communists and Capitalists. Economic growth is the new religion.

Can the economy grow forever? A solution used to be to conquer new lands to find raw materials and energy sources. Nowadays we turn to science for raw materials and energy. And there’s a third kind of resource: knowledge. And it is potentially infinite.

Economic growth disproportionately affects the poor, as they benefit most from growth and suffer most from stagnation.

However, economic growth also means environmental damage, and the poor suffer disproportionately from that as well. So its a double-edged sword. Poverty? Or suffering at the hands of ecological collapse?

Aside: I don’t buy Harari’s premise here. Sure, the modern deal conflicts with meaning and religion – but it is surely not a condition that we renounce our belief in a great cosmic plan in order to participate. Many a banker is devout Christian. Humans have an incredible capacity for contradictory beliefs – which is one of Harari’s main points in Sapiens.

New Religion: Humanism

There is no God to worship – instead we worship humanity and expect humanity to play the role that God(s) played in ancient religions.

Old religions: the world has a plan and each life has inherent meaning. Primary creed of humanism is the opposite: the world has no plan, and humanity must create meaning for a meaningless world.

“If I believe in God at all, it is my choice to believe. If my inner self tells me to believe in God –then I believe. I believe because I feel God’s presence, and my heart tells me He is there. But if I no longer feel God’s presence, and if my heart suddenly tells me that there is no God –I will cease believing. Either way, the real source of authority is my own feelings. So even while saying that I believe in God, the truth is that I have a much stronger belief in my own inner voice.”

Humanism in five points:

When Nietzche says “God is dead”, it’s not that traditional religion is annihilated. Rather, the power has shifted from God to the individual. (At least in the humanist West).

The old formula for knowledge: scriptures * logic.

The new formula: empirical data * mathematics.

However, science cannot solve questions of ethics. Instead, enter the humanist formula: knowledge = experiences * sensitivity. This is similar to the 10,000 hours idea. You do something a lot and get a natural feel for its nuances — sensitivity.

Humanism has changed art and culture as well. Less focus on god and greatness. Much more on the individual, emotions, and change through experiences.

Humanism evolved and split into three main branches. Orthodox branch (liberalism) believes each human is unique. Socialist humanism is about unifying workers of the world and prioritizing the needs of the group rather than the individual. The lastly, evolutionary humanism, strongly rooted in Darwinian evolutionary theory, believes in conflict and natural selection to move the human race forward.

Interesting thought experiment. Compare four experiences: listening to Beethoven, listening to Chuck Berry, listening to a traditional Congolese Pygmy chant, or a wolf listening to a wolf howl. Liberals say the first three are equal, but wolf is lesser. Socialists say Beethoven was made for the upper class (bad!), Chuck Berry is white appropriation of African American music culture (bad!), and Congolese Pygmy chant represents a patriarchal society (bad!). Leave it to the party to rank them. And evolutionary humanists say: Beethoven did better than the others, sorry not sorry.

“According to evolutionary humanists, anyone arguing that all human experiences are equally valuable is either an imbecile or a coward. Such vulgarity and timidity will lead only to the degeneration and extinction of humankind, as human progress is impeded in the name of cultural relativism or social equality.”

The Humanist Wars

Starting 1914 until 1989, the humanist groups went to war. Socialism saw liberalism as giving everyone the right to be “free to starve”. Evolutionary humanists saw the other two groups as dooming humankind evolutionarily and saw the pursuit of equality as preventing us from allowing natural selection to do it’s thing and create ‘superhumans’.

Interesting thing that Harari points out here is how WWII was won not by the liberals, but by socialists. Perhaps socialism, while bad at GDP growth and knowledge growth, is better at war? It views the individual as less important than the group or party – so that makes sense.

Surprised by the dismal outlook of the world in the 70s. Looked like liberal democracy had failed. Liberal democracy existed in the US, Northern Europe, and India. But then India threatened to go socialist with Indira Gandhi, we lost Vietnam and all of Southeast Asia. We were the leaders of the free world and yet all of our allies were dictators.

But then – thanks to economic growth – liberalism win. And it has more humility now. It has adopted ideas from its socialist and fascist rivals, such as providing the general public with education, health, and welfare services.

“If you value national health services, pension funds and free schools, you need to thank Marx and Lenin (and Otto von Bismarck) far more than Hong Xiuquan or the Mahdi. Why did Marx and Lenin succeed where Hong and the Mahdi failed? Not because socialist humanism was philosophically more sophisticated than Islamic and Christian theology, but rather because Marx and Lenin devoted more attention to understanding the technological and economic realities of their time than to scrutinising ancient texts and prophetic dreams.”

Part 3: Homo Sapiens Loses Control

Liberalism sanctifies human experience and human life. By maximizing human lifespan, happiness, and power, we risk undermining the foundations of humanism.

First up on losing to scientific rigor: humans having free will. The evidence is largely to the contrary now.

Aside: another good read on this is Free Will by Sam Harris.

Actions are not the result of free will. They are the result of genetic makeup, evolutionary processes, chance mutations, and developmental environment and experiences.

Of course, this brings about many complications – what if someone murders your child? Does the murderer get a defense argument that it “wasn’t free will”? Would you accept it? Is it true?

Studies have been conducted where you’re asked to make a decision – and it’s found that the subconscious reacts before the conscious does.

“The last nail in freedom’s coffin is provided by the theory of evolution. Just as evolution cannot be squared with eternal souls, neither can it swallow the idea of free will. For if humans are free, how could natural selection have shaped them? According to the theory of evolution, all the choices animals make –whether of habitat, food or mates –reflect their genetic code. If, thanks to its fit genes, an animal chooses to eat a nutritious mushroom and copulate with healthy and fertile mates, these genes pass on to the next generation. If, because of unfit genes, an animal opts for poisonous mushrooms and anaemic mates, these genes become extinct. However, if an animal ‘freely’ chooses what to eat and with whom to mate, then natural selection has nothing to work with.”

Since the brain is just electrical signals, you can use nodes, helmets, etc. to control the brain – or at least to alter it. If you can wear a helmet that makes decisions to help you a better football player or sharpshooter or mathematician… do you still have free will?

Multiple selves: the left and right brain are basically two different people – and the right brain is hushed by the left.

An old treatment for epileptic patients was to sever the connection between the left and right brain. This effectively created two separate individuals that you could ask questions to. Subjects studied had eerie behavior. One kid was asked verbally what he wanted to be when he grew up: he said a draughtsman. But when asked visually (so right brain could reply), he said automobile racer.

The left brain makes up stories to explain inconsistencies. This was also observed with the split brain patients. The right brain saw something and the body reacted to it – the left brain didn’t know about it, but would construct a story to make it work.

Interesting thought experiment:

“Suppose you can choose between two potential holidays. You can go to Jamestown, Virginia, and visit the historic colonial town where the first English settlement on mainland North America was founded in 1607. Alternatively, you can realise your number one dream vacation, whether it is trekking in Alaska, sunbathing in Florida or indulging in an unbridled bacchanalia of sex, drugs and gambling in Las Vegas. But there is a caveat: if you choose your dream vacation, then just before you board the plane home, you must take a pill that will obliterate all your memories of that vacation. What happened in Vegas will forever remain in Vegas. Which holiday would you choose? Most people would opt for colonial Jamestown, because most people give their credit card to the narrating self, which cares only about stories and has zero interest in even the most mind-blowing experiences if it cannot remember them.”

Narrating self may spin up a crazy story that you believe about yourself. Let’s say you think you’re a hero, like Don Quixote. Your imagination leads you to kill a real person. How do you react? Three possibilities: (1) nothing, your delusions are so strong you don’t realize it; (2) you’re horrified and snap out of your delusions; (3) you double-down on your delusions.

The third is called “Our Boys Didn’t Die In Vain” syndrome. You can see it with politics and war. Say you start a war which is a mistake; 15,000 die. If you double back, the families of those people will be enraged. So you double-down and fight harder instead.

We’re about to face the wrath of post-humanist technologies that make no allowance for the free will of humans. Will humanist systems predicated on human free will, like democracy, free market, and human rights survive?

The Group Decoupling

Liberalism did not succeed because it was philosophically superior or “more correct” than other belief systems. It worked because there was political, economic, and military sense in giving every individual value. Countries that cared for the individual had better economies, stronger militaries, and more robust political systems, and thus fared better.

The next threat will make humans less valuable in every way listed above. Technology will render us economically obsolete and militarily useless.

Humans value in war will be reduced or eliminated as the responsibility falls to algorithms/worms (cyberwarfare), robots (drones), or highly specialized teams.

Same for economic value.

“As the masses lose their economic importance, will the moral argument alone be enough to protect human rights and liberties? Will elites and governments go on valuing every human being even when it pays no economic dividends?”

Corollary: same argument goes against Universal Basic Income. If you provide no economic or warfare value, then why should the Gov’t take care of you? What do they owe you if they dont rely on you for taxes or warfare?

And the argument against that argument: some basic welfare will be required to maintain stability and keep the economic engine running.

Intelligence versus Consciousness

“This raises a novel question: which of the two is really important, intelligence or consciousness? As long as they went hand in hand, debating their relative value was just an amusing pastime for philosophers. 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.”

Many people say robots are cold, thus human touch is necessary. But even this is not always true anymore.

Unemployable Class

Harari calls them the “useless class” – pretty harsh.

Harari argues all jobs will be automated. There is nothing unique about an organic algorithm (ie: human) that can inorganic one cannot replicate. We are all just a series of algorithms.

Humans used to be generalists: hunting, cooking, making spears, building huts, farming… Now we are specialists: taxi drivers, programmers, cardiologists. And specialization makes us much easier to replace with AI.

“As algorithms push humans out of the job market, wealth and power might become concentrated in the hands of the tiny elite that owns the all-powerful algorithms, creating unprecedented social and political inequality.”

Main problem is not creating new jobs: it’s creating jobs that humans can do better or cheaper than algorithms.

Liberalism says:

  1. I am an individual. I have a single essence that cannot be divided into smaller parts
  2. My self is completely free.
  3. I know things about myself nobody else can discover.

Life sciences challenges all three assumptions:

  1. Organisms are algorithms, and humans are divisible into millions of bits.
  2. Humans are not free – they are shaped and run by their algorithms.
  3. It follows that an external algorithm could know you better than yourself.

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