Book Summary21 Lessons for the 21st Century, by Yuval Noah Harari

1-Page Summary1-Page Book Summary of 21 Lessons for the 21st Century

The 21st century will bring changes and challenges unlike any humans have encountered before. Globalism and technological innovations are changing the structures of societies worldwide—and the changes are happening quickly. This book highlights the biggest challenges in the modern world, and it offers advice on making sense of and navigating such transitional times. If people don’t become better informed about the present and participate in shaping the future, the world could have a class of obsolete workers whose jobs have been automated, people could lose their ability to make their own decisions, and nuclear weapons could annihilate much of the world.

Part 1: Political, Economic, and Social Realities Are Changing

Technological innovations are changing the structures of society—from politics to the labor market. If humans are to address these challenges, they’ll need to create new tools and approaches that fit this new context.

Politics: The Fall of Liberalism

For centuries, people have developed political models that fit the political, economic, and social context of the time, and these models provided a story to make sense of the world and an ideal future to work toward. In recent decades, the dominant political story has been liberalism, which promoted individual freedoms—through free trade, low taxes, free elections, peaceful international relations, rights for minority groups, and pro-immigration policies. However, the massive technological innovations are automating jobs, broadening inequality, and altering human behavior in ways that are making the liberal story irrelevant—and people must either adapt an old political model to modern times or create a new one.

Parallel revolutions in infotech and biotech are transforming societies by:

• Making technology too complex for most people to understand. Many people are uninformed about how machines are changing the labor market and algorithms are influencing the way they think, shop, and vote.
• Allowing humans to alter their own bodies. Whereas past innovations altered the external world—for example, by building dams—new technology is being developed to alter humans’ internal worlds, such as slowing the aging process through bioengineering.

Economy: Technology Is Transforming the Labor Market

In the 21st century, increasingly sophisticated technology could automate so many jobs that unemployment skyrockets among low-skilled workers. Neurological discoveries and technological innovations will enable machines to do jobs better than people can, because machines are immune to human error and biases.

Large-scale automation will likely cause a net loss in employment, creating a “useless class” of unskilled workers. Some workers will be able to get training in a new set of skills, but technology will continue to change so rapidly that those new skills could also become obsolete a decade later. This could eventually create a post-work society, in which workers face a fight against irrelevance and governments must determine alternative ways to support people.

Society: Technology Threatens Human Liberty

In addition to threatening jobs, technology threatens human liberty, as algorithms learn so much about people that they gain an immense power to influence and manipulate. Liberalism maintains that everyone has free will to choose how to vote, how to act, and what to buy—but algorithms can make better choices than you do. For instance, Netflix’s algorithm might suggest a movie that fits your tastes better than one you would have picked.

Each decision that algorithms make for you has two effects:

1. Your trust in the algorithm increases. When Netflix suggests a movie, and you end up loving it, that experience reinforces your reliance on Netflix’s recommendation. As you gain trust in Netflix, you also lose trust in your own choices.
2. The algorithm learns more about your preferences, which enables it to make even better decisions for you in the future. As the algorithm gains more knowledge about you, it will make better choices for you, which will reinforce your increasing trust in its decision-making and decreasing trust in your own.

People’s reliance on algorithms can easily snowball to big life decisions, such as where to go to college, which career to pursue, and who to marry.

Society: Technology Could Worsen Inequality

As technology threatens to create a useless class of unskilled workers and algorithms have the potential to overpower free will, inequality could grow exponentially: On one end of the spectrum will be the useless class, and on the other end will be the wealthy CEOs of tech companies. Making matters worse, biotech innovations could enable wealthy elites to become biologically superior by improving their physical and cognitive abilities and extending their lives. If wealthy elites gain biological advantages over the poor—and the poor are pushed out of opportunities to work and gain wealth—it could create a vicious cycle that continually widens the gap between haves and have-nots. Taken to the extreme, bioengineering could eventually turn the rich into a separate species with no need for the underclass of commoners.

Part 2: Address Challenges With Global Solutions

Now that we’ve laid out the challenges, let’s explore potential methods that societies can use to address them.

Method #1: Tackle Issues Through Communities

How will humans tackle the massive challenges they face in the 21st century? One option is to band together and tackle them as communities. Facebook CEO Mark Zuckerberg wants to facilitate this by using AI to suggest groups that might be meaningful to individual Facebook users. The goal is to use the social media platform and the algorithmic tools to rebuild communities online in order to improve connections among people throughout the world. However, the project will only work if these online...

21 Lessons for the 21st Century Summary Introduction

The 21st century will bring changes and challenges unlike any humans have encountered before. Globalism and technological innovations are changing the structures of societies worldwide—and the changes are happening quickly. 21 Lessons for the 21st Century highlights the biggest challenges in the modern world, and it offers advice on making sense of and navigating such transitional times. In five parts, the book:

1. Takes stock of the current political and technological state
2. Examines potential methods for societies to deal with modern challenges
3. Discusses how humans can prevail over these challenges
4. Questions how to make sense of the emerging world
5. Explores how to find personal meaning in this world

This book is intended to inform people who feel too busy and...

21 Lessons for the 21st Century Summary Part 1: Technology | Chapter 1: Liberalism Is Becoming Irrelevant

Lesson: Liberalism—which values personal freedoms, free trade, and free elections—is the dominant political model today, but technological changes are transforming the political, social, and economic structures on which liberalism stands.

Political models have always served the purpose of providing a story to make sense of the world and an ideal future to work toward. That story depends on the political, economic, and social context at the time. As a result, there have been several times throughout human history when the political model of the day became irrelevant and needed to be replaced.

Feudalism and monarchism were the reigning political models until the Industrial Revolution created such upheaval in economics and politics that those models no longer fit. In response, in the 1900s, elites around the world developed three new political stories, each of which offered a different way of making sense of the world and shaping the future:

1. The fascist story: There have been tensions and struggles among nations throughout history. In an ideal future, one nation flexes its power over all others, but violence is likely.
2. The communist story: There have...

21 Lessons for the 21st Century Summary Chapter 2: Technology Will Create a Useless Class

Lesson: Technological innovation is enabling AI to perform an increasing number of jobs, which will cause massive unemployment.

One of the biggest challenges of the 21st century will be a fundamental change in the labor market caused by technological disruption. In other words, increasingly sophisticated technology could automate so many jobs that unemployment skyrockets.

Throughout history, each new machine and labor-saving technology created at least as many jobs as it eliminated—for example, a piece of equipment that replaced a human laborer also required someone to operate the equipment and another person to do maintenance on it. Past innovations substituted human workers’ physical capabilities, but not their cognitive abilities. No matter how quickly a machine could sew a shirt compared to a seamstress, the machine couldn’t take customers’ measurements.

However, the dual rise of infotech and biotech is creating technologies that could truly replace the need for human workers. New discoveries in neuroscience have revealed that human skills such as analyzing, decision-making, communicating, and interpreting other people’s emotions are the results of...

Shortform Exercise: Could You Become a Member of the Useless Class?

Could widespread automation threaten your job?

In the time you’ve been working in your field, has any part of the industry been automated? If so, describe what it was.

21 Lessons for the 21st Century Summary Chapter 3: Algorithms Threaten Human Liberty

Lesson: As algorithms provide increasingly accurate suggestions, their convenience is almost irresistible—but relying on algorithms to make your decisions causes you to lose the freedom and ability to make your own choices.

In addition to threatening jobs, technology threatens human liberty, as algorithms learn so much about people that they gain an immense power to influence and manipulate. This is another way that technology is undermining liberalism, which is all about freedom and personal liberties—to vote, to buy goods in a free market, and to pursue individual dreams and goals with the protection of human rights.

Liberalism maintains that everyone has free will, regardless of education and social status. In practice, people’s choices of free will reflect their feelings more often than their knowledge. For example, between two presidential candidates, voters are more likely to choose the one who gives them a good feeling, even if the other candidate has a more thorough policy plan. Similarly, elected officials often make decisions based on gut feelings and intuition, even when they go against advisors’ recommendations. From the way voters vote to the way leaders lead,...

Shortform Exercise: How Present Are Algorithms In Your Daily Life?

You already use algorithms every day. Does the convenience outweigh any concerns?

List at least three ways that you use algorithms in your daily life (such as GPS navigation, Google search suggestions, Netflix recommendations, and social media feeds).

21 Lessons for the 21st Century Summary Chapter 4: Technology Is Worsening Inequality

Lesson: In addition to creating a useless class, technology gives wealthy elites access to health and economic advantages that exacerbate inequality, creating a vicious cycle.

As technology threatens to create a useless class of unskilled workers and algorithms have the potential to overpower free will, inequality could grow exponentially: On one end of the spectrum will be the people who become unemployed when computers automate their jobs, and on the other end will be the wealthy CEOs who own the tech companies that automated those jobs.

Inequality has always existed to varying degrees in human societies:

• During the Stone Age, some people were buried with jewels and other goods, while others were dumped into simple graves.
• After the Agricultural Revolution, inequality worsened as people possessed more property—in the form of animals, land, and tools—with which to distinguish between the haves and the have-nots.
• During the Industrial Revolution, a company’s and country’s success depended more than ever on masses of common workers, so equality became more important to societies and governments throughout the 20th century. Governments started...

21 Lessons for the 21st Century Summary Part 2: Politics | Chapters 5-6: Join Others to Tackle Modern Problems

Lesson: People’s social lives exist largely online, but people need communities and face-to-face interaction to thrive. In addition to maintaining close-knit communities, people must recognize and participate in the global civilization that exists today.

How will humans tackle the massive challenges they face in the 21st century? One option is to band together and tackle them as communities.

Besides food, water, and shelter, belonging to a community is essential for humans to survive and thrive. Throughout most of human history, people lived in small tribes, typically consisting of a few hundred people. In a community of this size, you can have some form of relationship with everyone, which optimizes group dynamics. However, in recent centuries, small tribes have been replaced with large nations—and some people believe that the loss of community has been a major factor in creating the challenges that modern societies face, from corrupt governments to drug addiction crises.

Facebook CEO Mark Zuckerberg believes so strongly in the restorative power of communities that he has made a mission of connecting Facebook users via virtual groups. Zuckerberg’s project uses AI to...

Shortform Exercise: What Role Do Communities Play in Your Life?

Reflect on the communities to which you belong, where they exist, and how they impact you.

List the online communities to which you belong. What is your role in each, and what makes each one meaningful to your life?

21 Lessons for the 21st Century Summary Chapters 7-8: Nationalism and Religion Divide People

Lesson: Many people around the world are finding comfort in the identity and community of their nations and faith—but nationalism and religion create an “us” and “them” mentality, which makes it difficult to come together as a global civilization to address collective problems.

Despite the undeniable existence of a global civilization, many countries are increasingly leaning into nationalism. People have returned to nationalism in recent years in response to modern challenges, but nationalism has deep roots in human society.

For millions of years, humans lived in smaller communities and tribes, but, over time, they merged to take on challenges that were too big for one group to handle. For example, ancient tribes near the Nile River relied on the water to grow their crops, but they constantly had to deal with years of drought and years of flooding. Each tribe had limited manpower and claimed a small section of the river, so, eventually, many tribes banded together to build dams and canals that benefited everyone.

Over time, nation-states formed, and people used culture as a tool to achieve cooperation among a mass of people. The nationalism that resulted has two distinct...

21 Lessons for the 21st Century Summary Chapter 9: Immigration Exacerbates Tensions Between Cultures

Lesson: Nationalist divisions strain debates around immigration, which further exacerbates division—but nations’ abilities to resolve disagreements about immigration will indicate how effectively they’ll be able to address global issues of the 21st century.

Immigration will increasingly be a flashpoint because of growing tensions among people of different nationalities as the global economy, increased international travel, and technology bring people together from across the world. If governments don’t find ways of addressing the fierce debates about immigration, people will be too divided to tackle the global challenges of the 21st century.

Immigration Strikes a Deal Between Migrants and Countries

Immigration requires an understood deal between migrants and host countries—but immigration opponents say that immigrants aren’t holding up their end of the deal, while immigration advocates say that host countries are falling short. We’ll explore this debate within each of the three terms of this deal:

1. The host country lets immigrants enter.
2. The immigrants adopt the host country’s basic values and norms, even when it conflicts with their traditional...

Shortform Exercise: How Do You Define the Terms of Immigration?

Reflect on your definitions of the terms of immigration, and how well your beliefs align with your country’s policies.

Do you believe countries have an obligation to accept immigrants? Why or why not?

21 Lessons for the 21st Century Summary Part 3: Perspective | Chapters 10-11: Terrorism and War Are Minor Threats

Lesson: Don’t waste too much energy worrying about terrorism, because it is a relatively minor threat unless terrorists get nuclear weapons. Similarly, military warfare is an increasingly remote possibility in the modern world.

In recent decades, fear of terrorism has gripped the world, ignited wars, and shaped politics—and that’s by design. With the exception of outliers like 9/11, most acts of terrorism kill very few people; far more people die in traffic accidents or from diabetes. As the name suggests, terrorism is meant primarily to incite terror, but it generally causes little physical damage.

In an attack, most military strategists aim to destroy the enemy’s most powerful weapons and essential resources, in order to handicap any retaliation. However, terrorists don’t have the power to inflict such damage, so their attacks often do little to harm their enemies’ weapons, equipment, and infrastructure. Due to their weakness in resources and manpower, terrorists’ only hope is to aggravate the enemy so much that it overreacts, and that the overreaction creates enough chaos and instability that the power balance tips in the terrorists’ favor. In other words,...

21 Lessons for the 21st Century Summary Chapter 12: People Overestimate Their Culture’s Importance

Lesson: People have inflated perceptions of their culture’s importance and contributions to the world.

Even when war brings high costs and promises little reward, there are a host of reasons that leaders do it anyway. One major reason is that national leaders—as well as many people in general—overestimate the importance of their own culture and its impact on the world. Greeks, Chinese, and Hindus are just a few of the cultures that claim that history began with their ancestors’ achievements. However, this skewed view shows a lack of humility and a disregard for history. In reality, morality, creativity, art, and spirituality can’t be credited to any single culture because they’re wired into human DNA.

Although nearly every culture perpetuates similarly self-important myths, we’ll break down the flaws in this view by examining the Jewish culture and claims of Jewish achievements.

Case Study: Jewish Culture

Children are raised with a misunderstanding of their culture’s importance, as school history lessons emphasize certain events, downplay others, and frame history based on how it affected their ancestors. For instance, when Israeli students learn about the...

Shortform Exercise: Are You Overestimating Your Culture’s Importance?

You may be spreading your culture’s self-important myths without realizing it.

Reflect on your history education in school as well as current media and pop culture. How is your culture generally characterized?

21 Lessons for the 21st Century Summary Chapters 13-14: People Don’t Need God to Keep Social Order

Lesson: Many religious laws are meant to keep social order, but people are driven to cooperate regardless of religious convictions.

Just as people wrongly credit their cultures for contributing to society and maintaining social order, people mistakenly attribute morality to religion. In reality, humans are hard-wired to maintain social order, and religion has worked both for and against this cause

When people talk about God, they can be referring to one of two versions:

1. The cosmic God is grand and mysterious, and humans know nothing concrete about Him. He is the answer to all unanswered questions: What is the meaning of life? What shaped the world? This is the philosophers’ God, which embodies human ignorance and speculation.
2. The lawgiver God is strict and judgmental, and humans know plenty about Him and His preferences. He has specific rules about what people can wear, eat, drink, and do. This is the God of homophobes, jihadists, and Crusaders.

Religious people talk about both gods as one—declaring that He is a mysterious force, but also that He has very clear rules about gay marriage. However, these two views of God are contradictory. **If God is an...

Shortform Exercise: What Guides Your Morals?

Reflect on how you distinguish right from wrong.

Is your moral compass guided by religious values, laws, or some other force?

21 Lessons for the 21st Century Summary Part 4: Truth | Chapters 15-16: You Know Less Than You Think

Lesson: You’ll never be able to understand everything about how the world works—and that’s OK, as long as you recognize your ignorance and don’t overestimate your knowledge.

In order to find truth, you must recognize what you know—and what you don’t know. Modern society has an incredible amount of information at its fingertips, yet, individually, people know far less than their ancestors. In the Stone Age, hunter-gatherers knew how to hunt, make fire, and escape predators. Today, individuals don’t need the same breadth of knowledge because they have access to a global network of collective knowledge and others’ expertise.

Our ability to access collective knowledge has been critical to humankind’s incredible progress and achievements—but it’s also led to two dangerous phenomena:

1. The knowledge illusion: People mistake group knowledge for individual wisdom, and their tendency to underestimate their own ignorance is having dangerous consequences. Lawmakers with no scientific training are creating policies on climate change that affect not just the nation but the world (as we discussed in Chapter 7).
2. Groupthink: **People become so convinced of and loyal to the...

21 Lessons for the 21st Century Summary Chapters 17-18: People Love Stories—Even When They’re Lies

Lesson: Humans are so driven to make sense of the world through stories that they’re often willing to believe lies.

We are living in a post-truth society, in which lies aren’t merely spread in social media posts, but they are also used to justify government actions. For example, when Russia invaded Crimea in 2014, the Russian government repeatedly denied responsibility for the invasion. The government rationalized that its lie served a higher purpose, which was to reunify Ukraine with Russia.

How did we get to this era of post-truth? The phenomenon has a long history. In fact, the great accomplishments of human progress are owed in part to humans’ ability to create and get others to believe fictional stories in order to work together toward a collective goal. In other words, humans’ penchant for stories allows strangers to cooperate for common causes. Storytelling is used in this way by different kinds of institutions, including:

1. Religion: The stories found in the Bible, Torah, Quran, and other holy texts have inspired millions of people to work together to build cathedrals, fight oppression, and even fight bloody wars.
2. Nations: Governments spread...

21 Lessons for the 21st Century Summary Part 5: Meaning | Chapter 19: The Education System Is Outdated

Lesson: The modern education system is designed to prepare students for a job market that’s becoming obsolete.

The education that children today receive will determine how well-equipped they are not only to navigate but also to shape the future. However, the modern education system is not fit to prepare children for the 21st century.

First, humans don’t know what the world will look like in 50 or 100 years. This has always been true to some extent, but, in the past, people could reasonably predict what kinds of jobs would exist and generally how government and politics would function by the time their children and grandchildren became adults. Now, technology makes it impossible to know which jobs will become obsolete, what the global political system will look like, and whether the human body will have new capabilities as a result of bioengineering. Without having a reasonable expectation of the future, it’s impossible to know how to prepare children for it.

Second, the focus and the goal of the modern education system are outdated. In centuries past, information was scarce. Depending on where you lived, you had access to books, radio, and television—and whatever...

Shortform Exercise: How Well Did Your Education Prepare You?

Reflect on whether your education gave you the tools to succeed as an adult.

Besides fundamental skills like reading and writing, how often do you use the knowledge you learned in grade school (K-12)?

21 Lessons for the 21st Century Summary Chapter 20: People Seek the Meaning of Life in Stories

Lesson: People are driven to uncover their reason for living, and they often look for answers in meaning-of-life stories or within themselves.

As people prepare for a new reality and new challenges in the 21st century, they’ll inevitably ponder, “What is the meaning of life?” When people ask this question, what they’re really asking is, “What is the meaning of my life? What is my role in the universe?” Humans have been asking these questions throughout history. More often than not, people want the answer to fit into a story, because humans love stories, and they use stories to make sense out of the world.

Meaning-of-Life Stories Are Illogical

Throughout human history, people have come up with countless stories to explain the meaning of life, including:

• All life forms on the planet are part of an eternal circle of life, and you have a unique role in that cycle. The purpose of life is to find your function and to fulfill it. This explanation is powerful because it claims that an infinite cycle connects all people from the past, present, and future. The circle-of-life explanation also assigns everyone an identity and reason for living, and you merely...

Shortform Exercise: What’s Your Meaning of Life?

Reflect on how you search for the meaning of life.

If you’ve contemplated the meaning of life, where do you look for answers?

21 Lessons for the 21st Century Summary Chapter 21: Understand Your Mind Through Meditation

Lesson: You must understand your mind in order to make sense of the world, and meditation is one of the best ways to do that.

In order to understand life, you must understand your own mind, because your mind determines how you experience, interpret, and react to the world around you. When you understand your mind—including its biases, fears, and complexes—then you can choose your actions more wisely and execute them more effectively. There are many ways to get in tune with your mind, including art, therapy, and physical activity. The author’s method of choice is meditation, which takes your attention away from the noise and distractions of the external world and focuses it on the reality of your breath and bodily sensations. Observing each inhale and exhale keeps your attention on the present reality, which offers a clearer view of life than any story or dogma can.

The better you know your mind, the more you’ll realize that your thoughts and emotions are not as straightforward as you probably think. As we’ve discussed, your thoughts are a reflection of your brain wiring and your external influences. Furthermore, your emotions are a reflection of your physical...

21 Lessons for the 21st Century Summary Final Thoughts

In a Q&A, the author shares some final thoughts about how to approach the 21st century’s biggest challenges. The key takeaways include:

• Of all the stories that humans use to make sense of the world, the two most dangerous are nostalgic fantasies and technological utopias. Nostalgic fantasies misrepresent the past, and they wrongly imply that the past offers solutions to modern problems. Technological utopias suggest that simply creating new technologies will solve big problems, when the more important question is how to use the technologies.
• Believing in the myth of free will makes you vulnerable to manipulation, because you don’t...