What are the great challenges of our era, what do they mean and how can we deal with them?
A review and key takeaways from Yuval Noah Harari’s book “21 Lessons for the 21st century”
Disclaimer: This review represents my take on this book. It is not a summary nor replace its reading. Its goal is to help us reflecting on key issues raised by the author as well as encouraging more people to read the full book.
It is no wonder that Yuval Noah Harari is regarded as one of the main thinkers of our time and that his books are recommended by Barack Obama, Angela Merkel and Bill Gates, among other global personalities. Keynote speaker at the Davos World Economic Forum in both 2018 and 2020, Harari manages to connect complex issues from different fields in a simple and objective way. Regardless of whether we agree or not with his views, his texts are benchmarks of a fluid and pleasant writing style that is inviting to reflection.
In “Sapiens,” his first best-seller with over 21 million copies sold worldwide, Harari condensed approximately 200,000 years of our species into less than 300 pages. His central idea is that we only came to dominate the world thanks to our ability to cooperate in large groups in a socially flexible way. We are the only species on the entire planet capable of collaborating on a large scale with individuals who are not our relatives. Interestingly, we are able to do this thanks to our incredible ability to believe in fictions that only exist in our minds.
Despite being a concept discussed for a long time by anthropologists and sociologists, Harari somehow shocked the world by claiming that we spend our whole lives immersed in a great collective fantasy, an intersubjective reality formed by countries, religions, ideologies, companies, and money. None of these things exist in a concrete way: they are just widely shared stories that allow us to coexist collectively. Our ability to live in two worlds — one imaginary and another real — has reached such a point that the fate of the real world made up of rivers, animals and forests depends nowadays on our decisions in the imaginary world that we jointly experience every day.
In “Homo Deus”, his second book, Harari turned to the future: What will be the agenda of humanity after overcoming chronic problems that have plagued us for centuries, such as famine, poverty, and wars? What will happen when we acquire the power to create new life forms artificially? What will we become as a species if some people manage to upgrade their bodies and minds so as to increase their abilities and extend their lives indefinitely? The book contains a fundamental warning: we are gradually acquiring powers over life and the world that our ancestors would have considered a privilege of gods. The problem is that our wisdom and awareness have not evolved at the same pace as our technological advancements. For Harari, this combination of almost divine powers with little wisdom may become lethal to our species in a not-too-distant future.
In “21 Lessons for the 21st Century,” Harari turns to the present: What is happening in the world today? What are our biggest collective challenges and choices we need to make? What should be the focus of our attention?
The book begins by analyzing the growing disillusionment with liberalism around the world, particularly in the United States and Europe. This political and moral philosophy, characterized by ideas such as democracy, the rule of law, market capitalism, globalization, human rights, individual freedoms, and press freedom, has become a consensual vision of the future for humanity after the fall of the Berlin Wall. To such an extent that, in the 1990s, many pundits came to proclaim “the end of history”.
History, however, has not ended. The resurgence of nationalism, the backlash against globalization, and the election of several populist and authoritarian leaders in recent years have shown that a large fraction of the population is questioning the value of liberalism. In particular, the vote for Brexit in the UK and the election of Donald Trump in the US in the year 2016 represented the moment when this wave of mass disillusionment reached the core of liberal states in Europe and North America.
What is the cause of this growing disillusionment? Basically, the perception that the current socioeconomic system is not working well and that the prospects for the future are not positive. Most people, if not the vast majority, live in a condition of great insecurity and chronic stress. Too many demands and pressures, little stability and predictability. On the top of it, the average citizen is faced with an increasingly complex world whose new technologies (such as artificial intelligence, big data, blockchain, etc.) and debates (such as climate change, fourth industrial revolution, etc.) are very difficult for him or her to understand.
There is a growing perception in the population that the majority of people are becoming economically irrelevant and being abandoned by the elites.
There is a growing perception in the population, therefore, that the majority of people are becoming economically irrelevant and being abandoned by the elites. For Harari, these people will not suffer from exploitation, but from something far worse — irrelevance. That’s why the masses are trying to make use of the remaining political power to support nihilistic leaders who, with a rhetoric based on patriotism and religion, promise a return to a nostalgic past that in fact never existed.
Harari believes that what we most need right now around the world, is a compelling story that provides a vision for the future for humanity. Why? Because, with the discredit of the liberal story, we are currently without a clear story for our collective future. In one of his brilliant passages, he sums up our situation: “In 1938 humans were offered three global stories to choose from, in 1968 just two, and in 1998 a single story seemed to prevail. In 2018 we are down to zero. No wonder that the liberal elites are in a state of shock and disorientation… To be suddenly left without any story is terrifying.”
What we most need right now, around the world, is a compelling story that provides a vision for the future for humanity.
For the author, the most dangerous thing today is that we are losing faith in the liberal story exactly when we are facing two of the greatest challenges our species has ever faced: technological disruption — caused by the merger of information technology with biotechnology — and climate change.
The most dangerous thing today is that we are losing faith in the liberal story exactly when we are facing two of the greatest challenges our species has ever faced: technological disruption and climate change.
Starting with the first challenge. Artificial intelligence can do a lot of good, but it can also bring big risks. The first one is the impact on the labor market. Sooner or later, virtually all professional activities will be affected by new technologies.
Many argue that, just like the technological advances of earlier times, many more jobs will be created, and a large job market will continue to exist. For Harari, there is good reason to believe this time will be different. He reminds us that humans have two types of abilities: physical and cognitive skills. Machines have long surpassed us in physical capability. Over the years, artificial intelligence will increasingly surpass us also in our cognitive skills: the ability to learn, analyze, communicate and, above all, understand human emotions.
Harari also remarks that artificial intelligence enjoys two additional capabilities compared to humans. The first is connectivity. Because computers can easily be integrated into flexible networks, people will not be replaced by an isolated computer, but rather by integrated networks. Therefore, we need to compare the abilities of a set of human beings against the abilities of an integrated network. Harari gives the example of autonomous vehicles: when two vehicles controlled by artificial intelligence approach an intersection, they are not two separate entities — they are part of the same algorithm.
The second additional advantage of artificial intelligence is the ability of being constantly updated. In the example of the autonomous vehicles, all cars could be instantly and simultaneously updated with new rules or technologies. The same idea applies to medicine. The digital doctors of artificial intelligence will be constantly updated with the latest scientific discoveries or treatment protocols, something impossible to do with the millions of human doctors around the world.
For Harari, the potential advantages of connectivity and real-time updating are so big that, in at least some activities, it might make sense to replace all human beings with computers, even if some humans do a better job than machines. He also thinks that, in the long run, no job will be completely safe from automation. Not even that of artists, who ultimately work by triggering the widest range of human emotions. In a not-too-distant future, artificial intelligence will become master in understanding and manipulating our emotions through art.
For all those reasons, Harari argues that we could end up with the worst of both worlds: high unemployment and, at the same time, a shortage of skilled labor. This will generate a mass of people who will not only be unemployed, but simply unemployable. He warns that the fate of this useless class will not be similar to that of former 19th century wagon drivers (who became taxi drivers with the advent of cars): they might have the same fate of 19th century horses, who were simply eliminated of the job market altogether.
We could end up with the worst of both worlds: high unemployment and, at the same time, a shortage of skilled labor. This will generate a mass of people who will not only be unemployed, but simply unemployable.
Another important observation is that the artificial intelligence revolution will not be a one-off event from which the labor market will adjust to a new equilibrium: it will be a succession of ever-increasing disruptions over the next few decades.
The question we must ask ourselves, indeed, is the following: will people have, in addition to technical skills, the mental energy and the emotional balance to deal with a life full of upheavals that will force them to constantly reinvent themselves? It is important to note that, even before the arrival of the Covid-19 pandemic, we were already experiencing a mental health crisis in the business world.
Harari believes, notwithstanding, that the biggest risk from the merger of infotech and biotech is not its impact on the labor market: it is the transfer of decision-making authority to algorithms. For him, this would allow a small elite to hack people’s brains and manipulated them in such a way that might give rise to “digital dictatorships”.
The biggest risk from the merger of infotech and biotech is the transfer of decision-making authority to algorithms. For Harari, this would allow a small elite to hack people’s brains and manipulated them.
The risk to democracy is enormous. Its value derives from the idea that we must respect the collective choice of the population expressed by the free will of each individual. The problem is that this supposed “free will” is much more emotional than rational. That’s why Harari warns that “once somebody acquires the technological ability to hack and manipulate the human heart, democratic politics will mutate into an emotional puppet show.”
This is a central argument of his book: In a not-too-distant future, algorithms based on big data will be able to monitor and understand our feelings better than we do. How? Through biometric sensors that might analyze our reactions to the most varied situations. Gradually, we would hand over to algorithms the authority to make the major decisions of our lives.
This is a central argument of his book: In a not-too-distant future, algorithms based on big data will be able to monitor and understand our feelings better than we do.
In some way, this is already happening. We automatically use Google to know the “truth” about something. We use Waze or Google Maps to get anywhere without challenging its routes. And algorithmic-powered dating sites are already the main source for dating in the US: 39% of couples of the country have first met on these websites, a more popular source of dating than work, friends, or family. Sooner or later, Harari predicts that the idea of “free will” will be exposed as a myth. Consequently, liberalism — including the values of democracy and free markets — will lose its main base of support.
At this point, the author makes another insightful consideration. When artificial intelligence reaches a point in which it will be able to decide what is best for us better than ourselves, the psychological impact on our lives is likely to be profound. We are used to seeing life as a succession of decisions. What will happen to our outlook about life when we entrust artificial intelligence with the power to make decisions about our careers, relationships, and other crucial choices?
One possibility, according to Harari, is that we will start seeing the universe as a huge flow of data and organisms as little more than biochemical algorithms. In this case, humanity will have the cosmic vocation of creating and unifying data processing systems that encompass everything. He believes that this is already happening: “even today, without realizing it, we are already becoming small chips within a large data processing system that nobody understands.”
Another characteristic of artificial intelligence based on machine learning is that it works better when it has more data to analyze. A consequence of this feature is that, for the first time in history, centralized systems might become more efficient than decentralized ones. In politics, this means that authoritarian regimes may have a decisive advantage in monitoring, manipulating, and controlling the population.
He describes a hypothetical, but perfectly possible example from the technological standpoint, that could occur in a regime like North Korea in a not-too-distant future: “Each North Korean citizen might be required to wear a biometric bracelet that monitors everything that person does and says, as well as their blood pressure and brain activity… The North Korean regime might be able for the first time in history to gauge what each and every citizen is thinking at each and every moment. If a North Korean looks at a picture of Kim Jong-un and the biometric sensors pick up the telltale signs of anger, that person will be in the gulag tomorrow morning.”
Harari believes that this potential problem is not restricted to dictatorships. Currently, for example, democratic countries like the United States and Israel are implementing systems to increase the surveillance of their citizens. If this issue is not publicly discussed and well-regulated by society, we might see the emergence of true digital dictatorships based on total monitoring and on an ability to understand our internal feelings far superior to the Big Brother imagined by Orson Orwell in his “1984” book.
In addition to the political risks, the merger of information technology and biotechnology can produce the most unequal societies that have ever existed. It all depends on who owns the data. For Harari, data will become the most important asset in the 21st century and politics will be characterized by a constant arm wrestling to define who controls its access. If data are concentrated in just a few hands, the outcome can be disastrous.
In addition to the political risks, the merger of information technology and biotechnology can produce the most unequal societies that have ever existed. It all depends on who owns the data. If data are concentrated in just a few hands, the outcome can be disastrous.
He warns that the race to control the data has already started, led by giants like Amazon, Google, Facebook, Baidu, and Tencent. Most of these companies adopted the business model of “attention merchants”. They capture our attention by providing us “free of charge” information, services, and entertainment. Harari points out that the real business of these data giants is not selling ads: it is accumulating a huge amount of data about us that is worth much more than the ads. As he sums it up: “We aren’t their customers — we are their product”.
For Harari, it will be very difficult for us to resist this process: “At present, people are happy to give away their most valuable asset — their personal data — in exchange for free email services and funny cat videos. It’s a bit like African and Native American tribes who unwittingly sold entire countries to European imperialists in exchange for colorful beads and cheap trinkets. If, later on, people decide to try to block the flow of data, they might find it increasingly difficult as they might come to rely on the network for all their decisions.”
The author believes that humans and machines are going to merge so fully that we will simply not be able to survive if we disconnect from the network. Concomitantly, it will become increasingly easier for companies and governments to know us, manipulate us, and make decisions on our behalf. That’s why Harari believes that our biggest danger today is to spend too much time developing artificial intelligence and too little time developing human consciousness. If that happens, then “the very sophisticated artificial intelligence of computers might only serve to empower the natural stupidity of many humans… We might have to deal with hordes of bots that know how to press our emotional buttons and use this uncanny ability to try to sell us something — be it a car, a politician, or an entire ideology.”
He also highlights that inequality might reach unimaginable levels in the coming decades, extrapolating the financial dimension. Economic inequality is already huge: the richest 1% in the world own around half of all the wealth in the world, while the richest 100 people in the world have a wealth similar to that of the poorest four billion. This situation could get worse, as the rise of artificial intelligence tends to reduce or even eliminate the economic value and political power of many people.
Inequality might reach unimaginable levels in the coming decades, extrapolating the economic dimension.
At the same time, improvements in biotechnology in areas such as genetic editing, bioengineering and nanotechnology could, for the first time, turn economic inequality into biological inequality. In this case, the richest would start enjoying not only a much longer life expectancy, but also different abilities compared to ordinary citizens.
Once a real gap in talent, intelligence and capability is established between the rich and the poor, it will be almost impossible to eliminate it. Over time, this could lead to the emergence of different castes or even different species. According to Harari, “by 2100, the richest 1 percent might own not merely most of the world’s wealth but also most of the world’s beauty, creativity, and health. The two processes together — bioengineering coupled with the rise of artificial intelligence — might result in the separation of humankind into a small class of superhumans and a massive underclass of useless Homo sapiens… For the first time in history, maybe there will be no ‘we’ anymore”.
“The two processes together — bioengineering coupled with the rise of artificial intelligence — might result in the separation of humankind into a small class of superhumans and a massive underclass of useless Homo sapiens… For the first time in history, maybe there will be no ‘we’ anymore”.
In another important part of the book, Harari defends an argument that is quite simple, but at the same little understood by many people: we need global solutions to successfully tackle the global problems of our era. This means that we will only be able to deal with the risks of technological disruption, climate change and nuclear wars — each one enough by itself to threaten our collective future — through global cooperation and substantial commitments by each country to the international community.
That is why, for Harari, the current nationalist wave has been an obstacle to solve our global problems. It is not the case that he is against a healthy nationalism characterized by appreciation for compatriots. The problem, for the author, is that the current nationalist wave focuses not on love for fellow countrymen, but on hate for foreigners who come to be seen as enemies (in his view, the same reasoning applies to the upsurge of religion in many places).
Harari argues that if we really care for our compatriots, then we need to understand that we are part of a great human civilization. We must welcome, as a result, multilateral efforts aiming to overcome the great challenges of our era. In politics, this means supporting politicians at all levels who give due attention in solving our global problems.
Harari exemplifies his argument with climate change. We are rapidly approaching critical points from which the ongoing ecological collapse will be very unlikely reversed. That’s why we need answers right away, not next year or in 2050. For him, the problem is that nationalists tend to put their short-term interests first, believing that they can worry about the environment later. As they do not have a national solution to the global climate problem, many simply prefer to believe that the problem does not exist.
After discussing other issues such as the impact of social media, the current role of religion, immigration, and terrorism, Harari gives a more personal tone to the book. He begins by reflecting on what we can do about the big questions of our time. For him, if we feel overwhelmed and confused by the current situation in the world, then we are on the right path. Global processes have become too complicated for a single individual to understand. How then can we know the truth about the world and avoid becoming victims of propaganda, disinformation, and manipulation?
If we feel overwhelmed and confused by the current situation in the world, then we are on the right path. Global processes have become too complicated for a single individual to understand.
The first step is to understand the extent of our ignorance and biases. Our rationality is a myth. What is often sold as rationality is, in fact, just rationalization. Harari reminds us that not only rationality, but individuality is also a myth, as we rarely think on our own. Indeed, we think in groups. Most of our views are shaped by the collective thinking of the groups we are part of, not by our individual rationality.
To a large extent, we form these visions out of loyalty to our groups. That’s why the author argues that providing people with more and more information is unlikely to make things better. This hope is based on a misunderstanding of how we really think. As he sums it up: “Most people don’t like too many facts, and they certainly don’t like to feel stupid.”
A big challenge, according to Harari, is that “the world is becoming ever more complex, and people fail to realize just how ignorant they are of what’s going on… People rarely appreciate their ignorance, because they lock themselves inside an echo chamber of like-minded friends and self-confirming news feeds, where their beliefs are constantly reinforced and seldom challenged.”
In a particularly important passage for business leaders, Harari points out that knowing the truth is even more difficult when we are in positions of power. In addition to the fact that information is often presented in a biased way and that leaders are immersed in excessively homogeneous groups, the frenetic pace of those at the top makes reflection even more difficult, as it prevents these individuals from delving into any topic. In another remarkable section, he says: “If you want to go deeply into any subject, you need a lot of time, and in particular you need the privilege of wasting time and make space for doubts and boredom. If you cannot afford to waste time, you will never find the truth.”
Knowing the truth is even more difficult when we are in positions of power: “If you want to go deeply into any subject, you need a lot of time, and in particular you need the privilege of wasting time and make space for doubts and boredom. If you cannot afford to waste time, you will never find the truth.”
In the coming decades, the world will become even more complex. Our individual ignorance will only tend to increase. As much as we try to update ourselves, the knowledge we manage to accumulate is linear, while the content accumulated in the world is exponential. We will know less and less in relative terms about any specific field. That is why recognizing our individual limitations is critical. Learning will increasingly depend on collaboration, and organizations will need to to use the collective intelligence of all their members rather than relying on the intelligence of just a few.
Ethics is another subject handled with mastery by Harari. He accurately observes that ethical behavior is not just the outcome of good intentions and abstract values, but, above all, of a concrete understanding of cause-and-effect relationships. That is, on understanding the consequences of our actions or omissions.
Ethical behavior is not just the outcome of good intentions and abstract values, but, above all, of a concrete understanding of cause-and-effect relationships.
Unfortunately, a feature of our globalized world is that cause-and-effect relationships are complex and ramified. It’s hard to answer even seemingly simple questions like “where does my lunch come from?”, “who made the shoes I’m wearing?” and “what is my pension fund doing with my money?”. Because it’s so complicated to understand what we’re actually doing, it’s so hard to act ethically nowadays.
How can we behave ethically in such an intricate world? Many resort to the morality of intentions: what matters is my intention, not the consequences of what I do, of what I consume, or of the destination of my savings. Resorting to the blessing of ignorance is a subterfuge, not a solution.
For Harari, the supreme ethical imperative in a world where everything is interconnected is a duty to know. This means constantly making a sincere effort to understand the consequences of our actions or inactions. As he sums it up: “The greatest crimes in modern history resulted not from hatred and greed but even more so from ignorance and indifference.”
“The greatest crimes in modern history resulted not from hatred and greed but even more so from ignorance and indifference.”
Harari also discusses education. How should we educate ourselves — and our children — in this age of disorientation? Certainly, he argues, it is not with a traditional education based on providing more information. What people need is to know how to make sense of information. That is, being able to critically analyze information and aggregate pieces of data so that they can form a comprehensive view of the world.
For us and our children, the most important thing will be to develop the ability to cope with continuous change, to constantly learn new things, and to overcome unfamiliar or uncomfortable situations. We will need, above all, a lot of openness, mental flexibility, and emotional balance to let go our dogmas and reinvent ourselves repeatedly throughout our lives.
This is far from simple. In particular, as we get older: “After a certain age, most people just don’t like to change… By the time you are fifty, most people prefer stability. Having invested so much in their skills, career, identity and worldview, people don’t want to start all over again. You may continue to enjoy some new experiences and small adjustments, but most people in their fifties are not ready to revisit the deep structures of their identity and personality.”
The difficulty, according to Harari, is that people will not be able to live in stability in the 21st century: “If you try to hold on to some stable identity, job, or worldview… you might have to spend many decades as a clueless fossil. To stay relevant — not just economically, but above all socially — you will need the ability to constantly learn and reinvent yourself, certainly at a young age like fifty.”
“If you try to hold on to some stable identity, job, or worldview… You might have to spend many decades as a clueless fossil. To stay relevant — not just economically, but above all socially — you will need the ability to constantly learn and reinvent yourself, certainly at a young age like fifty.”
It is in this chapter that the author offers the oldest advice of the book: know yourself. To successfully navigate the 21st century, we will need to work hard to know who we are and what is (or not) relevant to us. The last two chapters of the book help us answering these fundamental questions. Harari resorts to Buddhism, a philosophy that permeates his books, to discuss the meaning of life and the importance of meditation to know ourselves better.
For Harari, the meaning of life is not a story, whether it is a ready-made plot (as in the case of religions) or a plot created by ourselves (as advocated by the liberal idea, which argues that it is up to each of us to create a meaning for our lives based on our free will): “any story is wrong, simply for being a story. The universe just does not work like a story.” For him, the big question we must ask is not “what is the meaning of life?”, but “how can we stop suffering” with experiences such as anger, anguish, anxiety, and sadness.
The big question we must ask is not “what is the meaning of life?”, but “how can we stop suffering” with experiences such as anger, anguish, anxiety, and sadness.
One of the keys to stop suffering is to care less about our desires. The vast majority of people attach so much importance to their desires that they spend their lives trying to control and shape the world in order to fulfill them. It is the relentless pursuit — and the inevitable frustration — to fulfill our fantasies that causes most of our afflictions. For Harari, if we know the truth about ourselves and the world, then nothing can make us suffer.
To understand each other better, he gives his last recommendation: meditate. For him, this practice of direct observation of the mind is not an escape from reality: it means getting in touch with reality. It is only by meditating that Harari believes to have developed the focus and clarity that allowed him to write his books. He says with legitimacy: Harari has meditated about two hours a day for twenty years. In addition, every year he completely isolates himself in long retreats of one or two months.
To conclude, it is important to note that Harari’s book is not a set of prophecies. Nobody knows what the future will be like. It’s a book of possibilities about where things might go. If we don’t like any of these possibilities, such as the potential rise of digital dictatorships or ecological collapse, then we should do something about it right now.
Harari’s book is not a set of prophecies. Nobody knows what the future will be like. It’s a book of possibilities about where things might go. If we don’t like any of these possibilities, then we should do something about it right now.
It is also worth mentioning that staying away from these global debates will not spare us of their impacts on our everyday lives. For those who say that this is not fair, Harari declares: “But who said history was fair?”.
Unlike what the title suggests, 21 Lessons for the 21st Century is not a book of ready-made answers or prescriptions. It is a text that frames complex debates with incredible lucidity and logic using a historical and philosophical perspective.
It is up to us, readers, to continue this debate and act in a concrete way in our daily lives based on our conclusions. Clarity, by the way, is Harari’s trademark. It is not by chance that he begins the book with a phrase that is a fundamental takeaway to our lives: “In a world deluged by irrelevant information, clarity is power.”
Prof. Dr. Alexandre Di Miceli is a professional speaker, author, business thinker and founder of Virtuous Company, a top management consultancy providing cutting edge knowledge on corporate governance, leadership, business ethics, and future of the work.
He is the author of “The Virtuous Barrel: How to Transform Corporate Scandals into Good Businesses” as well as of the best-selling books on management, corporate governance and business ethics in Brazil, including “Leadership Pills: 10 Essential Readings for Building Organizations of Excellence in the 21st Century”, “Resilient Companies: Thriving in a World of Uncertainty”, “Corporate Governance in Brazil and in the World”, “Behavioral Business Ethics: Solutions for Management in the 21st Century”, and “Corporate Governance: The Essentials for Leaders”.
He thanks Prof. Dr. Angela Donaggio for her valuable comments and suggestions.
 Harari, Y. (2015). Sapiens: A Brief History of Humankind. Harper. 464 p.
 Harari, Y. (2017). Homo Deus: A Brief History of Tomorrow. Harper. 455 p.
 Harari, Y. (2018). 21 Lessons for the 21st Century. Random House. 400 p. Portuguese version: Harari, Y. (2018). 21 Lições para o Século 21. Companhia das Letras. 432 p.
 Ibid., p. 5.
 Ibid., p. 46.
 Source: Quartz. 12/02/2019. Around 40% of American couples now first meet online. Available at https://qz.com/1546677/around-40-of-us-couples-now-first-meet-online/
 Ibid., p. 56.
 Ibid., p. 64.
 Ibid., p. 78.
 Ibid., p. 79.
 Ibid., p. 70.
 Ibid., p. 75–77.
 Ibid., p. 223.
 Ibid., p. 223.
 Ibid., p. 225.
 Ibid., p. 231.
 Ibid., p. 269.
 Ibid., p. 269.
 Ibid., p. 285.
 Ibid., p. xiii.