# Books Review: "Sapiens", "Homo Deus" and "21 Lessons For The 21st Century", by Yuval Noah Harari

Introduction
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In this review I will consider one of the most important literary and cultural phenomena of the last 20 years - the ambitious trilogy of the Israeli historian Yuval Noah Harari. In these three books Harari takes into consideration the past of humanity (*Sapiens*), the present (*21 Lessons for the 21st Century*) and the future (*Homo Deus*), trying to trace the global lines of development from the Stone Age up to the abandonment of biological bodies in favor of synthetic ones, passing through Trump and the future of unemployment. Among his greatest strengths as an author are:

*   The ability to look at trends from a bias-free perspective (with some notable exceptions)
*   The ability to bring together insights from many different disciplines in a very effective way
*   The ability to involve the reader with clear and accessible, yet not simplistic, language

There are undoubtedly more relevant and specific texts on each of the many themes addressed by Harari. Likewise, many of the observations in the texts can be (and have been) criticized from various points of view and for a variety of reasons, like Harari’s generalist approach and the lack of details. But precisely the horizontality and the ambitious scope are the main assets that make this trilogy so interesting and worth reading.

Observing a macro-trend from a hyper-specialized perspective can allow us to detail its different facets and potential origins, but makes it more complex to bring together different and broader contributions. Harari has chosen not to tackle the issues he faced from a hyper-specialized point of view, sometimes lacking detailed knowledge on certain topics, but manages to insert them within a universal narrative. A reader of Harari might find far-reaching insights into this narrative to ask questions about the research trajectories of his discipline and its role in a global perspective. 

The purpose of my review is to anticipate and facilitate this exercise of reflection. For each of these three texts I’ve summarized a small set of broad key ideas to keep in mind while reading. In conclusion, I will summarize some of the criticisms that have been made against the three books. 

Sapiens
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The intersubjective myths
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One of the starting points underlying Harari's entire body of work concerns the realm of intersubjectivity and its ability to concretely intervene on the world through the creation of myths. Between individuality and collectivity there is a third front, which is neither an objective fact nor a subjective impression, but resides in a sort of shared creative subjectivity. Harari defines this realm as an emergent property of the interaction between the single nodes of the collective, capable of creating a super-consciousness with a will of its own. From this dimension, a series of powerful intersubjective myths have emerged over the millennia, which as we will see in the book include laws, gods, money, morals, patriarchy and nations. They exist neither only in the natural world (although they refer to it), nor only in the non-shared imagination, but in shared intersubjectivity. To understand humans it is therefore necessary to understand the intersubjective myths we share.

This ability to create myths is what distinguishes Homo Sapiens from other species. It exists because we know how to use imagination and language to create and communicate new worlds, alternatives and future possibilities not physically present in the current reality. The function of such shared myths in our development was essential, as it allowed us to cooperate, organize ourselves on a large scale and dominate the world. Collectively they are the glue that holds societies together: they give meaning to existence and help make choices in a highly complex world. Let's look at two examples of collective myths:

*   **Brands**. The Peugeot brand does not exist in the natural world: you could kill all Peugeot employees and destroy all their buildings and products, but the Peugeot brand would still exist. On the other hand, if a signature is placed on a company winding up document, the French car brand would cease to exist. It, therefore, exists as a "fiction" in the intersubjective imagination. Its power lies in its ability to coordinate humans to produce and consume on a large scale.
*   **Money**. Money represents a unit of exchange that functions only as a shared fiction. For Harari, money is "the height of human tolerance" because it is more open than any other shared fiction (language, laws, cultural codes or religious beliefs) and because it does not discriminate on the basis of ethnicity, religion, age or sexual orientation.

In summary, therefore, it can be said that the intersubjective myths are the glue that holds culture and, consequently, society together. From this derives an essential consequence: breaking the myth means breaking the culture, and therefore the social world that relies on this myth, leading to a dramatic and rapid change. As we have seen in the past, breaking the myth of monarchy, slavery, or patriarchy means changing the cultural model of society. Slavery, for example, with all its premises about human nature and hierarchy, has been a widely accepted myth for a long time. By questioning this myth entire cultures slowly changed their views about the topic, leading to a series of social revolutions.

The last reflection linked to this idea concerns the (non-existent, for Harari) difference between natural and chemical/artificial. This distinction makes no sense: the chemical elements are the basis of nature. Paracetamol, petrol, blueberries, our saliva and a quasar are made of the same chemical elements. Consequently, everything Sapiens can do by modeling chemistry is, by definition, natural. Biology opens the way for changes; it is culture that closes us by forbidding certain behaviors and labeling them as unnatural. In a sense there is no difference between natural and artificial but only between possible and impossible. The study of human culture often covers the study of what we prohibit and how we box such prohibitions within natural/unnatural rhetoric.

The three revolutions that created humanity
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Harari divides the history of man into three major revolutions, which as it will become clear in *Homo Deus*, will perhaps soon be followed by a fourth and more radical revolution. They are the cognitive revolution, the agricultural revolution and the scientific revolution.

*   The **Cognitive Revolution** occurred when winning genetic mutations slowly led humans to develop larger and more efficient brains. This evolution was undoubtedly one of our winning assets in the great war for adaptation and survival, but at the same time it can prove to be an important limitation today. Winning heuristics in the savannah do not work to engineer the right move for a job promotion.
*   The **Agricultural Revolution** led Homo Sapiens to become a sedentary species. According to a provocative yet interesting claim made by Harari, agriculture has given more evolutionary benefits to plant species scattered around the world than to us. Crop’s genes, for example, have spread around the world, making one among many plant species the most widespread species on the planet. It has been argued (even if it’s still a controversial topic) that the transition from a hunter-gatherer society to an agricultural society has led us toward less favorable existential conditions, decreasing our overall well-being and happiness. But, at the same time, with this transition our culture has grown, leading to stronger social ties. The birth of the sedentary agricultural tribes has brought stability, security and culture, but also more inequalities, an increase in internal violence (that, of course, is present even in hunter-gatherer tribes) and deficits in the body.
*   The **Scientific Revolution** has allowed the passage from a culture highly based on the unverifiable consequences of some myths to one founded on the verifiable consequences of other myths. The topic is complex and controversial, but science too, according to Harari, could be considered (at least partially) a myth. It has had the virtue of transferring power from arcane sources to empirical verification, opening the doors to doubt, uncertainty and investigation. As a consequence, science helped us to make better predictions and to build advanced technologies. Although the birth of science proved to be a fundamental step in the history of man, we could find ourselves, at this moment, at the gates of its potentially catastrophic effects (more, again, in *Homo Deus*)

The three engines of history
----------------------------

Another main theme of the book concerns the three main myths capable, according to Harari, of driving history. As always, following Harari, it is important to remember that each of these three engines actually has mythological foundations and does not represent anything tangible or material. It is possible to touch a coin and feel like we are touching “money” in itself, but a coin is just a symbolic representation of the concept. So there is no way to find a physical proof of the existence of nations, money or gods as concepts, but only as symbols of each concept. This does not mean, as already mentioned, that the effect of such intersubjective creations is not powerful. It is quite the opposite: these forces have been so powerful that they have shaped history indelibly.

*   **Empires**. Although today they are seen (with some exceptions, like with the Roman or the Ottoman Empire) by many as a terrible legacy of the past - the cause of wickedness and terrible wars of conquest - empires have represented the longest, most stable and unifying form of government in the history of humanity. They made it possible to move from separating tribalism to the union of multitudes within a single mythological container. Where before there was chaos, lack of information exchange and violent clashes, empires have brought clear boundaries, legislative and linguistic unity and a common currency. Obviously they have often adopted violent and abusive means to reach their goals, and this should not be forgotten, but at the same time it is also important to recognize the role they have played in the development of humanity. What remains, today, of the imperial legacy?
*   **Money**. A second driving force has been money. Barter, a primitive form of exchange, could only have advantages on limited small scales (like in families or in prison internal economies), but overall it’s a highly inefficient way of trading. How many liters of milk should the farmer exchange for a pair of shoes from the local shoemaker? Money, on the other hand, has proved to be perhaps the strongest glue in the history of humanity, since it is a highly clear and efficient currency. Clashes between different religious myths or between different imperial myths took place within a macro-cultural framework of reference in which the existence of money was not in doubt. The simplicity behind the idea of ​​money is what has allowed it to spread on a large scale: religions, empires and moral codes require adherence to complex structures of norms, while money requires accepting a single idea.
*   **Religion**. Religion is the third great unifier of the world, like money and empires. It is defined as a set of values ​​based on belief in a superhuman order and plays its role effectively when it is defined as "universal" and "missionary". *Universality*, opposed to the locality of the animist religions of hunter-gatherers, allows to unite even apparently distant peoples, while *missionarity* allows the ambassadors of the "new" system of values ​​to spread like a new actively pushed cultural meme.

21 Lessons
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The challenges of the new century
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In the central (and least original) book of the trilogy, Harari makes a series of reflections on a multitude of themes, trying to prefigure the main lines of development of this century. There are many issues addressed, and it would be impossible to focus on each of them in too much detail, so I will try to summarize only a few points of view.

*   **The social effects of algorithms**. Modern financial, political and economic systems rely heavily on complex algorithms. There have already been stock market crashes caused by algorithms that have not yet been fully understood. The effect of this complexity on citizens has been disorientation and difficulty understanding the future. This has led us, as evidenced by the revival of identity movements, religiosity and nationalism, to seek simple answers and to rely on strong leaders.
*   **The impossibility of ending research.** As we have seen, the effects of the radical advancement of science could lead to unprecedented social, economic and political upheavals. So why not regulate research to avoid the dangers? To this issue, widely discussed in other research arenas, Harari responds with pessimism: no global agreement would be able to stop an AI research laboratory located in the most hidden corner of North Korea. More likely, we could hope for the inefficient procurement of the resources necessary to advance the research resulting from these agreements. But hoping for total restraint is, according to Harari, practically impossible.
*   **The immigration dilemma.** Faced with an increasingly globalized world, the free movement of individuals is becoming an increasingly hot topic. According to Harari, the problem is particularly present in Europe, and to address it he breaks a lance in favor of both the opposite points of view (the pro- and the anti-immigrationist). The European Union (and its predecessors, like the ECSC) was born as a political and economical project to unite different peoples, nations and cultures (German, French, Italian, etc.) under the flags of tolerance, freedom and equality. The task seems to have been a success, given the extremely low level of violent conflicts that there have been in Europe in the last decades. Today, however, the European Union is facing the entry of a large number of people with structurally different values. Should coexistence be preferred between those who preach tolerance and those who oppose it, hoping for the creation of new systems of values? Or is it necessary that there are moral barriers to entry, which would unify European citizens within the liberal system of values? The debate, for Harari, must be addressed rationally, looking at the ideological differences from an impartial perspective.

Myths and post-truth
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As stated earlier, according to Harari, the extreme complexity of the modern world is leading to the rebirth of religious extremism and identitarian movements. This, however, is not to be considered as large a danger as it might appear. In fact, while extremist movements can give a sense of purpose and a clear moral compass to the everyday lives of their adherents, they are unable to make sense of modern problems. How can reading a thousand years old sacred text give us answers on the future of Artificial Intelligence? How can the sense of national identity help us understand the developments in genetic engineering? The problem is that we do not yet have solid alternative myths that can speak to the majority of people and not just to hyper-specialized audiences.

Complicating the scenario is the great question of the excess of information available. When it is possible to instantly access every possible point of view and its opposite, how can we recognize what is true? From this question arose the idea that we live in the age of post-truth. In a sense, it no longer matters to the general public what is true and what is false, whether a scientific remedy works or not, or whether a theory is valid or invalid. What counts is the narrative behind these ideas and the way in which they adapt to our already existing vision of the world. According to Harari, as already seen abundantly in *Sapiens*, humans have always preferred narrative over truth, and have always been guided by myths. Post-truth, therefore, is a phenomenon as old as mankind, and has nothing to do with the upheavals brought about by Twitter and fake news.

This brings us back to the topic of creating myths. Given the potential upheavals caused by scientific rationality and its effects on society, it becomes necessary to rethink different ways of creating new myths, which will push people to re-evaluate their existence. In an interesting chapter of the book, based on an article published in Wired, Harari points out the crucial role that science fiction will have in this mythopoeic enterprise. A piece of fiction based on science but able to effectively tell the social and personal consequences of technological developments could be the key to creating new glueing myths? Could the role of films like Inside Out and Interstellar have a more important cultural function than a highly-cited physics paper?

Skills of the future 
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A very interesting reflection concerns the most important skills that the inhabitants of the 21st century will have to possess, according to Harari. The transversal reflections on the theme cover more than one chapter. An important theory (but not the only one) states that the rate of acceleration of technological development and automation of tasks increases more or less constantly. If it’s true in the future the work we do today could become obsolete and the skills which we may have learned over the course of years useless in the job market, leaving us with a high probability of becoming unemployed. According to Harari, to get used to this frenetic pace of development it is necessary to teach the new generations more transversal skills, such as

*   **The ability to learn**. The need to constantly (and probably forever) learn new concepts, ideas and tools will reward those who will be able to learn quickly and effectively.
*   **Critical thinking**. In a world where the amount of data we receive is far higher than in the past, the problem of information scarcity is reversed. In a world where we can literally inform ourselves about everything and the opposite of everything, it becomes essential to reflect independently on the data received, filtering good data from bad and drawing only from sources that are reliable.
*   **Empathy and communication skills**. Even if algorithms become better than us in several cognitive domains, the average human’s brain will remain the same as that of hunter-gatherers. Essential elements in this sense are our need for socialization and empathy. Humor, understanding and affection may sooner or later be reproduced by a machine, but the time when we will see such reproduction is still far away. Much better, therefore, to learn to practice the art of compassion.

Thinking about learning to program in Java to secure a long-term future immersed in PCs can be a huge miscalculation. On the other hand, those who focus on acquiring more transversal skills will be much more advantaged. Ultimately, however, one should not rely too much on these individual skills, as according to Harari they will all be more or less destined to be emulated by algorithms. The meta-skill par excellence is therefore flexibility, the ability to understand and grow in a world where it is impossible to make confident predictions about the future.

Homo Deus
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The class of the useless
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According to Harari, this century will be defined, among other things, by two driving forces.

*   **Biological change**: numerous and radical innovations in the field of biotechnology, genetic engineering, cognitive enhancement and super-longevity (foundations of the transhumanist paradigm) will change the physical, mental and biological structure of human beings.
*   **Job change**: automation, the increasing power of algorithms and the development of technology will make almost all jobs fully automatable.

From these two premises follows a rather disturbing argument, one of the book's main points:

*   **Consequence of biological change**: the pace of development of innovations will be more and more rapid and will lead to a radical mutation of the bodies and minds of humans, giving them semi-divine abilities to control internal and external reality. The costs to be incurred to "keep up" with innovations in this sense will be too high and the prerogative of only a small elite of the super-rich.
*   **Consequence of the job change**: the "cognitive" advantage of humans over machines, up to now the guarantee of the birth of new jobs also as a result of automation processes, will disappear, leaving no possibility for people left behind to use their time in an economically productive way.
*   **Conclusion**: we will see a clear separation between a very small elite of super-rich with semi-divine powers able to shape reality more or less to their liking and an overwhelming majority of "useless" human beings, who will neither have the opportunity to empower themselves nor to spend their time on useful work.

The Marxist hypotheses about class struggle, in comparison, will be a nice thing of the past. Harari’s vision is bleak indeed: a scenario made up of semi-divine human beings, machines that do every job and billions of individuals drugged and immersed in virtual realities that distract them from the misery of their useless existence.

Dataism and techno-humanism
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According to Harari, the myth capable of demonstrating the highest degree of cultural resilience in history has been (and still is) liberal humanism. Born from centuries of philosophical stratifications, since the end of the USSR it has established itself as a central value in almost the whole of the earth, leading thinkers such as Francis Fukuyama to speak about the "end of history". Liberal humanism is founded on democracy, capitalism and tolerance, and celebrates human intelligence, experience, values ​​and uniqueness. According to Harari, in the next century we will see a rapid decline of this value.

To narrate the decline of liberal humanism, Harari starts by describing the intersection of two new sets of values, one rooted in more extreme assumptions (which he calls Dataism) and a more moderate one (which he calls techno-humanism and which we could define as transhumanism).

*   **Techno-humanism.** This system of values ​​is based on the search for immortality, overcoming the limits of biology, cognitive enhancement and the search for maximum happiness. These results can be achieved thanks to the joint work of artificial intelligence, genetic engineering, brain-machine interaction and other emerging technologies.
*   **Dataism**. Dataism is based on the idea that life itself is data processing, and everything is quantifiable, measurable and improvable through statistical analysis. By analyzing an increasing amount of data about our experiences, our biological parameters and a number of other sources, it will become possible to make algorithms more aware than ourselves of what we truly want. The value of an experience, for dataism, is given by the amount of useful data it can produce, not so much by anything phenomenological.

According to Harari, the intersection between these two value systems will lead to the overcoming of humanism. We have realized that in order to achieve the techno-humanist’s lofty goals it is necessary to use a large amount of data about ourselves. By aggregating them to try to get to know them better or to make the right choice, the algorithms will guide us in everyday life, until they become an essential element in our life. If, therefore, the fundamental value of liberal humanism is that of autonomy and if we realized that this autonomy is less effective in achieving the highest goals than delegating our choices to a machine, what will remain of humanism? What will happen to independence and individualism in the face of the idea that something external to us will know us better than we know ourselves?

According to Harari, the triumph of data will defeat the domain of individual autonomy, and morality will take on completely new and unimaginable shades. What values ​​will an immortal post-human being, enhanced and fused with data processing systems, believe in? To think that such a being can base its ethical system on what the disciples of monotheistic religions or of the scientific revolution have taught us is naive, and the question remains open.

The last step of this trajectory concerns the creation of what Harari calls the internet-of-all-things. If everything is an algorithm, if reality is permeated with data to be processed and if this processing allows to achieve better results in everything, then it is easy to assume that the next result will be that of creating an internet that permeates the whole of reality, of an algorithm that is fused with every aspect of the planet, the galaxy or the entire universe. Obviously, here we are in the plane of pure science fiction speculation (or not?). But even the first steps towards the creation of this system will be the premise for the disappearance of Homo Sapiens.

Organisms are algorithms
------------------------

An interesting chapter of this wild flight concerns the thesis, which Harari defines as "accepted by biologists", according to which organisms are nothing more than algorithms. This is a thesis with strong philosophical implications, which should be investigated more carefully, but on which the book relies heavily. The idea is that everything that makes up an organism can actually be decoded and analyzed as data. The emotions we feel, the thoughts we have, the decisions we make and the values ​​we believe in are the summation of a series of chemical impulses in the brain, caused by neuronal activation patterns defined in part by our past experiences and in part by our background genetics. Nothing more. There is no "magical" component behind what Sapiens, or any other species, are and do.

In light of this, it becomes very easy to imagine the continuation of the reasoning. If what we are is determined by a series of clear and quantifiable contributing causes, then it becomes automatic to try to decode them in order to try to improve them. We can break everything down, quantify it, analyze it and try to create an enhanced version of it. Even human activities generally considered more "subtle" become simple material to decode: the most sublime art arises not from the work of the Muses, but from the release of combinations of neurotransmitters at the root of pleasure linked to every note, stroke or rhyme. Decode these combinations, create a system to produce new ones and you will have created a Van Gogh 2.0.

This reasoning also supports the hypothesis of complete work automation very well. If everything is permeated with data and if that data can be interpreted effectively by perfect machines that can do impeccable jobs with them, what is left for humans? This argument could face an anti-reductionist philosophical critique of the central thesis according to which “organisms are algorithms”. Personally, I lean towards materialist and physicalist positions, but there is no doubt that such laconic sentences on such complex issues can be subject to numerous criticisms.

The final step of the whole reasoning is very simple: the era of Homo Sapiens is nearing its end. In its place we will see the birth of Homo Deus, something that we cannot yet describe, but which we know will originate from the exponential development of all the social, technological and cultural trajectories described in the three books of the trilogy.

Conclusion
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This trilogy therefore offers us food for thought and many questions to answer. If those who have come to the end of this review should intend to launch themselves into the reading of the trilogy (personal advice: the three books lend themselves very well to audio reading) here are some general questions to keep in mind.

*   What is the real role of myths in the past, present and future of Homo Sapiens? Can we say that it was only fiction that made society so united?
*   Are organisms really algorithms? The reductionist approach in biology is commonly but not unanimously accepted (as Harari would like to imply). Is there some space of reality that cannot be transformed into readable data?
*   How realistic is the scenario proposed by Harari, according to which we will see a clear separation between a small elite of Homo Deus and an overwhelming majority of completely useless individuals? And if this scenario is plausible, what kind of interventions can be implemented to reduce its dystopian scope?
*   Are we really witnessing the end of liberal humanism? If so, what cultural narrative can replace it in the coming decades? How do the dataist and techno-humanist ideas that Harari speaks of fit into this theme?