KAHNEMAN: Could you elaborate on these possibilities? I mean, what's the distinction between predicting and setting up a range of possibilities?

HARARI: I think about it in visual terms, whether you try to narrow your field of vision, or to broaden it. For example, when you try to predict the weather for tomorrow, there are a lot of possibilities to begin with. It might rain, it might snow, there might be sunshine. And a good meteorologist, according to one view of science, is a meteorologist that takes this horizon of possibilities and narrows it down to a single possibility or just two possibilities. It will certainly rain, maybe hard, maybe less so. That's it.

And after you finish reading the book or taking the course or whatever, your view of the world in this sense is narrower, because you have fewer possibilities to consider. You know it's going to rain. The same thing in economics, in medicine, and also in history. People ask what will happen next? You have all these possibilities, and I'm telling you, China is going to be the superpower, end of story. You narrow down the range.

There is room of course for that. When I go to the doctor to get a medicine, I want him to narrow down the possibilities, not just to enumerate all the options. But I personally like the kind of science that broadens the horizons. I often tell my students at the University that my aim is that after three years, you basically know less than when you first got here. When you first got here, you thought you knew what the world is like and what is war and what is a state, and so forth. After three years, my hope is that you will understand that you actually know far, far less, and you come out with a much broader view of the present and of the future.

KAHNEMAN: But do you get to a broader view by becoming more differentiated, that is, by having more detailed views? Or is it just that you get people to consider a possibility that wouldn't occur to them?

HARARI: Mainly, the second way. The main thing, and my main task as a historian is to get people to consider the possibilities which usually are outside their field of vision, because our present field of vision has been shaped by history and has been narrowed down by history, and if you understand how history has narrowed down our field of vision, this is what enables you to start broadening it.

Let me give you an example that I'm thinking about a lot today, concerning the future of humankind in the field of medicine. At least to the best of my understanding, we're in the middle of a revolution in medicine. After medicine in the 20th century focused on healing the sick, now it is more and more focused on upgrading the healthy, which is a completely different project. And it's a fundamentally different project in social and political terms, because whereas healing the sick is an egalitarian project ... you assume there is a norm of health, anybody that falls below the norm, you try to give them a push to come back to the norm, upgrading is by definition an elitist project. There is no norm that can be applicable to everybody.

And this opens the possibility of creating huge gaps between the rich and the poor, bigger than ever existed before in history. And many people say no, it will not happen, because we have the experience of the 20th century, that we had many medical advances, beginning with the rich or with the most advanced countries, and gradually they trickled down to everybody, and now everybody enjoys antibiotics or vaccinations or whatever, so this will happen again.

And as a historian, my main task is to say no, there were peculiar reasons why medicine in the 20th century was egalitarian, why the discoveries trickled down to everybody. These unique conditions may not repeat themselves in the 21st century, so you should broaden your thinking, and you should take into consideration the possibility that medicine in the 21st century will be elitist, and that you will see growing gaps because of that, biological gaps between rich and poor and between different countries. And you cannot just trust a process of trickling down to solve this problem.

There are fundamental reasons why we should take this very seriously, because generally speaking, when you look at the 20th century, it's the era of the masses, mass politics, mass economics. Every human being has value, has political, economic, and military value, simply because he or she is a human being, and this goes back to the structures of the military and of the economy, where every human being is valuable as a soldier in the trenches and as a worker in the factory.

But in the 21st century, there is a good chance that most humans will lose, they are losing, their military and economic value. This is true for the military, it's done, it's over. The age of the masses is over. We are no longer in the First World War, where you take millions of soldiers, give each one a rifle and have them run forward. And the same thing perhaps is happening in the economy. Maybe the biggest question of 21st century economics is what will be the need in the economy for most people in the year 2050.

And once most people are no longer really necessary, for the military and for the economy, the idea that you will continue to have mass medicine is not so certain. Could be. It's not a prophecy, but you should take very seriously the option that people will lose their military and economic value, and medicine will follow.

KAHNEMAN: You seem to be describing this as something that is already happening. Are you referring to developments such as the plans to do away with death? That absolutely would not be a mass project. But could you elaborate on that?

HARARI: Yes, the attitude now towards disease and old age and death is that they are basically technical problems. It is a huge revolution in human thinking. Throughout history, old age and death were always treated as metaphysical problems, as something that the gods decreed, as something fundamental to what defines humans, what defines the human condition and reality.

Even a few years ago, very few doctors or scientists would seriously say that they are trying to overcome old age and death. They would say no, I am trying to overcome this particular disease, whether it's tuberculosis or cancer or Alzheimers. Defeating disease and death, this is nonsense, this is science fiction.

But, the new attitude is to treat old age and death as technical problems, no different in essence than any other disease. It's like cancer, it's like Alzheimers, it's like tuberculosis. Maybe we still don't know all the mechanisms and all the remedies, but in principle, people always die due to technical reasons, not metaphysical reasons. In the middle ages, you had an image of how does a person die? Suddenly, the Angel of Death appears, and touches you on the shoulder and says, "Come. Your time has come." And you say, "No, no, no. Give me some more time." And Death said, "No, you have to come." And that's it, that is how you die.

We don't think like that today. People never die because the Angel of Death comes, they die because their heart stops pumping, or because an artery is clogged, or because cancerous cells are spreading in the liver or somewhere. These are all technical problems, and in essence, they should have some technical solution. And this way of thinking is now becoming very dominant in scientific circles, and also among the ultra-rich who have come to understand that, wait a minute, something is happening here. For the first time in history, if I'm rich enough, maybe I don't have to die.

KAHNEMAN: Death is optional.

HARARI: Death is optional. And if you think about it from the viewpoint of the poor, it looks terrible, because throughout history, death was the great equalizer. The big consolation of the poor throughout history was that okay, these rich people, they have it good, but they're going to die just like me. But think about the world, say, in 50 years, 100 years, where the poor people continue to die, but the rich people, in addition to all the other things they get, also get an exemption from death. That's going to bring a lot of anger.

KAHNEMAN: Yes. I really like that phrase of "people not being necessary," can you elaborate on this dystopia? It's a new phrase for me. Such things, by the way, are developing very, very slowly. I was worrying about what computers would do in displacing people. I was worried about this when I was a graduate student, and that was more than 50 years ago, and I thought that's a very serious, immediate problem. It wasn't a serious immediate problem then, but a serious ... not immediate, but it may be a serious problem now. You have thought about it deeply, can you tell us about people becoming unnecessary, economically, and unnecessary militarily? What will that do?

HARARI: The basic process is the decoupling of intelligence from consciousness. Throughout history, you always had the two together. If you wanted something intelligent, this something had to have consciousness at its basis. People were not familiar with anything not human, that didn't have consciousness, that could be intelligent, that could solve problems like playing chess or driving a car or diagnosing disease.

Now, what we're talking about today is not that computers will be like humans. I think that many of these science fiction scenarios, that computers will be like humans, are wrong. Computers are very, very, very far from being like humans, especially when it comes to consciousness. The problem is different, that the system, the military and economic and political system doesn't really need consciousness.

KAHNEMAN: It needs intelligence.

HARARI: It needs intelligence. And intelligence is a far easier thing than consciousness. And the problem is, computers may not become conscious, I don't know, ever ... I would say 500 years ... but they could be as intelligent or more intelligent than humans in particular tasks very quickly. And if you think, for example, about this self-driving car of Google, and you compare the self-driving car to a taxi driver, a taxi driver is immensely more complex than the self-driving car.

There are a zillion things that the taxi driver can do and the self-driving car cannot. But the problem is that from a purely economic perspective, we don't need all the zillion things that the taxi driver can do. I only need him to take me from point A to point B as quickly and as cheaply as possible. And this is something a self-driving car can do better, or will be able to do better very quickly.

And when you look at it more and more, for most of the tasks that humans are needed for, what is required is just intelligence, and a very particular type of intelligence, because we are undergoing, for thousands of years, a process of specialization, which makes it easier to replace us. To build a robot that could function effectively as a hunter-gatherer is extremely complex. You need to know so many different things. But to build a self-driving car, or to build a "Watson-bot" that can diagnose disease better than my doctor, this is relatively easy.

And this is where we have to take seriously, the possibility that even though computers will still be far behind humans in many different things, as far as the tasks that the system needs from us are concerned, most of the time computers will be able to do better than us. And again, I don't want to give a prediction, 20 years, 50 years, 100 years, but what you do see is it's a bit like the boy who cried wolf, that, yes, you cry wolf once, twice, three times, and maybe people say yes, 50 years ago, they already predicted that computers will replace humans, and it didn't happen. But the thing is that with every generation, it is becoming closer, and predictions such as these fuel the process.

The same thing will happen with these promises to overcome death. My guess, which is only a guess, is that the people who live today, and who count on the ability to live forever, or to overcome death in 50 years, 60 years, are going to be hugely disappointed. It's one thing to accept that I'm going to die. It's another thing to think that you can cheat death and then die eventually. It's much harder.

While they are in for a very big disappointment, in their efforts to defeat death, they will achieve great things. They will make it easier for the next generation to do it, and somewhere along the line, it will turn from science fiction to science, and the wolf will come.

KAHNEMAN: What you are doing here, in terms of prediction, is about trends. The trend is clear, what progress means is clear, but when you describe people as superfluous, you are presenting the background for a huge problem. Who decides what to do with the superfluous people. Especially, what are the social implications that you see, the technical or technological development that you foresee?

HARARI: Well, again, I am an historian, I am not a biologist, I'm not a computer scientist, I am not in a position to say whether all these ideas are realizable or not. I can just look from the view of the historian and say what it looks from there. So the social and philosophical and political implications are the things that interest me most. Basically, if any of these trends are going to actually be fulfilled, then the best I can do is quote Marx and say that everything solid melts into air.

Once you really solve a problem like direct brain-computer interface ... when brains and computers can interact directly, to take just one example, that's it, that's the end of history, that's the end of biology as we know it. Nobody has a clue what will happen once you solve this. If life can basically break out of the organic realm into the vastness of the inorganic realm, you cannot even begin to imagine what the consequences will be, because your imagination at present is organic. So if there is a point of Singularity, as it's often referred to, by definition, we have no way of even starting to imagine what's happening beyond that.

Looking before the point of Singularity, just as the trend is gathering pace, one thing we can say is there may be a repeat of what happened in the 19th century with the Industrial Revolution, of the opening of huge gaps between different classes and different countries. Generally speaking, the 20th century was a century of closing gaps, fewer gaps between classes, between genders, between ethnic groups, between countries. So maybe we are starting to see the reopening of these gaps with a vengeance, gaps that will be far greater then were between the industrialized and the non-industrialized part of the world, 150 or 200 years ago.

In the Industrial Revolution of the 19th century, what humanity basically learned to produce was all kinds of stuff, like textiles and shoes and weapons and vehicles, and this was enough for the very few countries that underwent the revolution to subjugate everybody else. What we're talking about now is like a second Industrial Revolution, but the product this time will not be textiles or machines or vehicles, or even weapons. The product this time will be humans themselves.

We're basically learning to produce bodies and minds. Bodies and minds are going to be the two main products of the next wave of all these changes. And if there is a gap between those that know how to produce bodies and minds and those that do not, then this is far greater than anything we saw before in history.

And this time, if you're not fast enough to become part of the revolution, then you'll probably become extinct. Countries like China, missed the train for the Industrial Revolution, but 150 years later, they somehow have managed to catch up, largely, speaking in economic terms, thanks to the power of cheap labor. Now, those who miss the train will never get a second chance. If a country, if a people, today are left behind, they will never get a second chance, especially because cheap labor will count for nothing. Once you know how to produce bodies and brains and minds, cheap labor in Africa or South Asia or wherever, it simply counts for nothing. So in geopolitical terms, we might see a repeat of the 19th century, but in a much larger scale.

KAHNEMAN: What I find difficult to imagine is that as people are becoming unnecessary, the translation of that into sort of 20th-century terms is mass unemployment. Mass unemployment means social unrest. And it means there are things going to happen, processes going to happen in society, as a result of people becoming superfluous, and that is a gradual process, people becoming superfluous.

We may be seeing that in the growing inequality now, we may be seeing the beginning of what you're talking about. But have you thought, in the same way as you're thinking in interesting and novel ways about technology, have you thought about the social side?

HARARI: Yes, the social side is the more important and more difficult one. I don't have a solution, and the biggest question maybe in economics and politics of the coming decades will be what to do with all these useless people. I don't think we have an economic model for that. My best guess, which is just a guess, is that food will not be a problem. With that kind of technology, you will be able to produce food to feed everybody. The problem is more boredom, and what to do with people, and how will they find some sense of meaning in life when they are basically meaningless, worthless.

My best guess at present is a combination of drugs and computer games as a solution for most ... it's already happening. Under different titles, different headings, you see more and more people spending more and more time, or solving their inner problems with drugs and computer games, both legal drugs and illegal drugs. But this is just a wild guess.

What I can say is that maybe we are again in analogous position to the world in 1800. When the Industrial Revolution begins, you see the emergence of new classes of people. You see the emergence of a new class of the urban proletariat, which is a new social and political phenomenon. Nobody knows what to do with it. There are immense problems. And it took a century and more of revolutions and wars for people to even start coming up with ideas what to do with the new classes of people.

What is certain is that the old answers were irrelevant. Today, everybody is talking about ISIS, and the Islamic fundamentalism, and the Christian revival, and things like that. There are new problems, and people go back to the ancient texts, and think that there is an answer in the Sharia, in the Qur'an, in the Bible. We also had the same thing in the 19th century. You had the Industrial Revolution. You had huge sociopolitical problems all over the world, as a result of industrialization, of modernization. You got lots of people thinking that the answer is in the Bible or in the Qur'an. You had religious movements all over the world.

In the Sudan, for example, you have the Mahdi establishing Muslim theocracy according to the Sharia. An Anglo-Egyptian army comes to suppress the rebellion, and they are defeated. They behead General Charles Gordon. Basically, this is the same thing that you're now seeing with ISIS. Nobody remembers the Mahdi today because the answers that he found in the Qur'an and the Sharia to the problem of industrialization didn't work.

In China, the biggest war of the 19th century is not the Napoleonic war, it's not the American Civil War, it's the Taiping Rebellion in China, which started in 1850, when a failed scholar named Hong Xuiquan, if I remember correctly, had a vision from God that he, Hong, is the younger brother of Jesus Christ, and that he had a divine mission to establish the Kingdom of Heavenly Peace on Earth, and to solve all the problems China had due to the coming of the British and of modern industry. He started the rebellion, and millions followed him. According to the most moderate estimates, 20 million people were killed in the Taiping Rebellion, and it was 14 years before they suppressed it. He didn't establish a Kingdom of Heavenly Peace, and he didn't solve the problems of industrialization.

Eventually, people came up with new ideas, not from the Sharia, and not from the Bible, and not from some vision. People studied industry, they studied coalmines, they studied electricity, they studied steam engines, railroads, they looked at how these developments transformed the economy and society, and they came up with some new ideas. Not necessarily everybody liked the new ideas, but it was something at least to argue against.

And looking from the perspective of 2015, I don't think we now have the knowledge to solve the social problems of 2050, or the problems that will emerge as a result of all these new developments. We should be looking for new knowledge and new solutions, and starting with the realization that in all probability, nothing that exists at present offers a solution to these problems.

KAHNEMAN: What is very interesting and frightening about this scenario is that it is true, as you point out, that people have lived to work, or worked to live, and that what you are describing is a scenario in which work is unnecessary for most people.

There is a class of people who work because they enjoy it, and are able to do it, and then there is most of humanity, for which work no longer exists. That mass of people cannot work, but they can still kill people. How do you see the possibility of strife and conflict, between the superfluous people and those who are not?

HARARI: Once you are superfluous, you don't have power. Again, we are used to the age of the masses, of the 19th and 20th century, where you saw all these successful massive uprisings, revolutions, revolts, so we are used to thinking about the masses as powerful, but this is basically a 19th century and 20th century phenomenon.

If you go back in most periods in history, say to the middle ages, you do see peasant uprisings. They all failed, because the masses were not powerful. And once you become superfluous, militarily and economically, you can still cause trouble, of course, but you don't have the power to really change things.

Once you have the revolution we are undergoing in the military in which the number of soldiers simply becomes irrelevant in comparison with factors like technology, you still need people, but you don't need the millions of soldiers, each with a rifle. You need much smaller numbers of experts, who know how to produce and how to use the new technologies. Against such military powers, the masses, even if they somehow organize themselves, don't stand much of a chance. We are not in Russia of 1917, or in 19th century Europe.

And so again, it's not a prophecy. Maybe it will turn out differently. But as a historian, the most important thing to realize is that the power of the masses, that we are so used to, is rooted in particular historical conditions, economic, military, political, which characterized the 19th and 20th centuries. These conditions are now changing, and there is no reason to be certain that the masses will retain their power.

KAHNEMAN: What you're describing, the scenario that you're pointing to, is one of fairly rapid technological progress, and it really doesn't matter whether we're talking about 50 years or 150 years. There is a social arrangement that has been around for a long time, for decades and centuries. And they change relatively slowly. So what you bring to my mind, as I hear you, is a major disconnect between rapid technological change and quite rigid cultural and social arrangements that will not actually keep up.

HARARI: Yes, this is one of the big dangers, one of the big problems with technology. It develops much faster than human society and human morality, and this creates a lot of tension. But, again, we can try and learn something from our previous experience with the Industrial Revolution of the 19th century, that actually, you saw very rapid changes in society, not as fast as the changes in technology, but still, amazingly fast.

The most obvious example is the collapse of the family and of the intimate community, and their replacement by the state and the market. Basically, for the entirety of history, humans lived as part of these small and very important units, the family and the intimate community, say 200 people, who are your village, your tribe, your neighborhood. You know everybody; they know you. You may not like them, but your life depends on them. They provide you with almost everything you need in order to survive. They are your healthcare. There is no pension fund; you have children, they are your pension fund. They are your bank, your school, your police, everything. If you lose your family and the intimate community, you're dead, or you have to find a replacement family.

And this was the situation for hundreds of thousands of years of evolution. Even once history started, say 70,000 years ago, and you see all the changes and agriculture and cities and empires and religions, you don't see any significant change on that level. Even in the year, say, 1700, most people in the world still live as part of families and intimate communities, which provide them with most of what they need in order to survive. And you could have easily imagined, at the beginning of the Industrial Revolution, that this will continue to be the situation.

If you were, say, an evolutionary psychologist back in 1800, and you saw the beginning of the Industrial Revolution, you could have very confidently said all these changes in technology are well and good, but they won't change the basic structure of human society. Human society is built from these small building blocks, the family and intimate community, because this is kind of an evolutionary given. Humans must have this. They cannot live in any other way.

And you look at the last 200 years, and you see them collapse after millions of years of evolution. Suddenly, within 200 years, the family and the intimate community break, they collapse. Most of the roles filled by the family and by the intimate community for thousands and tens of thousands of years, are transferred very quickly to new networks provided by the state and the market. You don't need children, you can have a pension fund. You don't need somebody to take care of you. You don't need neighbors and sisters or brothers to take care of you when you're sick. The state takes care of you. The state provides you with police, with education, with health, with everything.

And you can say that maybe life today is in some ways worse than in 1700, because we have lost much of the connection to the community around us ... it's a big argument ... but it happened. People today actually manage to live, many people, as isolated, alienated individuals. In the most advanced societies, people live as alienated individuals, with no community to speak about, with a very small family. It's no longer the big extended family. It's now a very small family, maybe just a spouse, maybe one or two children, and even they, they might live in a different city, in a different country, and you see them maybe once in every few months, and that's it. And the amazing thing is that people live with that. And that's just 200 years.

What might happen in the next hundred years on that level of daily life, of intimate relationships? Anything is possible. You look at Japan today, and Japan is maybe 20 years ahead of the world in everything. And you see these new social phenomena of people having relationships with virtual spouses. And you have people who never leave the house and just live through computers. And I don't know, maybe it's the future, maybe it isn't, but for me, the amazing thing is that you'd have thought, given the biological background of humankind, that this is impossible, yet we see that it is possible. Apparently, Homo Sapiens is even more malleable than we tend to think.

We can also learn something from the Agricultural Revolution. Some experts think that agriculture was the biggest mistake in human history, in terms of what it did to the individual. It's obvious that on the collective level, agriculture enhanced the power of humankind in an amazing way. Without agriculture, you could not have cities and kingdoms and empires and so forth, but if you look at it from the viewpoint of the individual, then for many individuals, life was probably much worse as peasants in ancient Egypt then as hunter gatherers 20,000, 30,000 years earlier. You had to work much harder. The body and mind of Homo Sapiens evolved for millions of years in adaptation to climbing trees and picking fruits and to running after gazelles and looking for mushrooms. And suddenly you start all day digging canals and carrying water buckets from the river and harvesting the corn, and grinding the corn, this is much more difficult for the body, and also much more boring to the mind.

In exchange for all this hard work, most peasants got a far worse diet than hunter-gatherers, because hunter-gatherers relied on dozens of species of animals and plants and mushrooms and whatever, that provided them with all the nutrients and vitamins they needed, whereas peasants relied on usually just a single crop, like wheat or rice or potatoes. And on top of that, you had all the new social hierarchies and the beginning of mass exploitation, where you have small elites exploiting everybody else. Putting all this together, there is a good case to be said for the idea that for the individual, agriculture was perhaps the biggest mistake in history.

This may provide us with a lesson, or at least something to think about with regard to the new technological revolution. Nobody would doubt that all the new technologies will enhance again the collective power of humankind, but the question we should be asking ourselves is what's happening on the individual level. We have enough evidence from history that you can have a very big step forward, in terms of collective power, coupled with a step backwards in terms of individual happiness, individual suffering. We need to ask ourselves about the new technologies emerging at present, not only how are they going to impact the collective power of humankind, but also how are they going to impact the daily life of individuals.

In terms of history, the events in Middle East, of ISIS and all of that, is just a speed bump on history's highway. The Middle East is not very important. Silicon Valley is much more important. It's the world of the 21st century ... I'm not speaking only about technology.

In terms of ideas, in terms of religions, the most interesting place today in the world is Silicon Valley, not the Middle East. This is where people like Ray Kurzweil, are creating new religions. These are the religions that will take over the world, not the ones coming out of Syria and Iraq and Nigeria.