Jared Diamond on the Downfall of Civilizations — and His Optimism for Ours

My guest today, Jared Diamond, has written some of the bestselling popular science books of all time, including Guns, Germs and Steel and Collapse. What might surprise you is that the study of civilizations, it wasn’t his first career, it wasn’t even his second career.

DIAMOND: The MacArthur grant means that people think that you can do more valuable things than gallbladders and even more valuable thing than New Guinea birds.

Welcome to People I (Mostly) Admire, with Steve Levitt.

I’ve long marveled over two things about Jared Diamond. First, how could anyone know so much about so many things as he does? And second, what sort of arrogance — err — self-confidence does it take to think that you can unravel some of the biggest, toughest questions in human history? My goal today is to figure out the answer to both those questions.

LEVITT: So, many listeners know your books like Guns, Germs, and Steel and Collapse — massive bestsellers. Few listeners, however, will have sampled your earlier writings like “Transport of Salt and Water in Rabbit and Guinea Pig Gallbladder,” or maybe “Effects of pH and Polyvalent Cations on the Selective Permeability of Gallbladder Epithelium to Monovalent Ions.” I don’t think I’m exaggerating when I say your research focus has changed more over time than anyone that I’ve ever known.

DIAMOND: It’s true. There are not many gallbladder experts who considered dropping out of science and then turned into geographers.

LEVITT: So, I’m curious, how did you initially get into the study of gallbladders?

DIAMOND: My father was a physician. So, I grew up with science in front of my eyes, but my mother was a concert pianist and a linguist. So, I also grew up with an interest in languages and in music. And then I was born in 1937, so I grew up during World War II. My father pinned up on the wall of my bedroom two maps: the map of Europe and map of Pacific. And every day, dad switched the pins to show the advance of the battle lines. Once I got to college, I realized what interested me was science. And so, having spent all my life until then in Boston, I went off to Cambridge, England. It was comfortably far from where I grew up and it was a world leader in physiology. For a Ph.D. thesis, because I’m technologically inept. I could not use fancy equipment. The simplest organ that I could think of was the gallbladder, which was just a hollow sack. I was one of the world’s five experts on the gallbladder. So, that’s how I got a job as professor of physiology at U.C.L.A. But then gradually my interest shifted — or rather shifted back — to history and geography. So, that was when I started writing books. And in 2002, finally, I switched to the department of geography here at U.C.L.A.

LEVITT: So, I didn’t realize you actually stuck with gallbladders for decades. But you somehow managed to carry on, as far as I can tell, three careers in parallel, because you haven’t mentioned anything about birds, but I’ve read that you’re quite a well-known ornithologist as well.

DIAMOND: Yes. In fact, among the scientific community as a whole, I’m better known for my work on birds than for my work on gallbladders. After the birth of my sons, I wanted to make a switch into geography and evolutionary biology, but that was difficult, first of all, because U.C.L.A., like I’m sure University of Chicago, doesn’t offer roving professorships. I couldn’t take my professorship and find a department and say, “Take me.” So, it was complicated to get myself transferred out of physiology.

LEVITT: So, anyone who’s read your books will know that your breadth of knowledge is remarkable. Your subject matter spans essentially all of human experience and across as many disciplines. Have you ever gotten yourself into trouble?

DIAMOND: Oh, of course. I get myself into troubles from two sources. One is that academics in general are trained to be academics and to write precisely and not to write interestingly and not to write in the first person. So, it’s a running problem for all of us who try to write for broad public. We get flack from academics who don’t write for a broad public, and there are many scandal stories such as Carl Sagan getting dis-elected from the national academy, not because he wasn’t a great scientist — he was — but precisely because he was a great scientist that wrote for the public.^[1] And the other source of flack is anthropologists. Anthropologists are touchy about people coming in from the outside, like me. But I should temper that by saying that those are fortunately the exceptions. For writing all of my books, I’m working, getting information in disciplines about which initially I know very little and I have to learn about it from other academics. And I find that the vast majority of academics, when I ask them to explain their subject matter, they love to explain it because they love to find someone who’s interested in what they are interested in.

LEVITT: After Freakonomics came out and we had some success in terms of publishing, there was a historian that I knew, and I was at a seminar he was at and clearly within my earshot, he grumbled that he would never want a wide audience to read his scholarship. With clearly a reference to the fact that I had somehow degraded myself by writing for a popular audience with Freakonomics. And I didn’t directly challenge him, but I thought to myself, what possible person could think that it makes more sense to write for 50 colleagues than to write for 50 colleagues and 5 million readers.

DIAMOND: It’s an interesting and it’s a sad question because understanding of science is essential for the broad public and understanding of science is essential not only to manage the world well, but also for academics to get research support for what they want to do. So, it’s ironic that academics should make it difficult for those who want to explain the excitement of their work to the broad public.

LEVITT: One aspect of your books that really sticks with me is the amazement I have over the ingenious methods that scholars have developed for taking the little scraps they’re given at archeological sites and extracting more insights about past societies than I ever could have imagined. Could you talk about some examples? And how you would piece together the story of how that society lived?

DIAMOND: Here’s one recent example: Genghis Khan, the Mongol chief Genghis Khan who established the largest land empire in world history — why did Genghis Khan do it? Was it that he was such a military genius? Well, he was a good organizer and yes, he was militarily very talented. But there are plenty of good organizers and people who are militarily talented everywhere in the world, including on the Steppes of Central Asia. Recently, paleontologists, people who study the past, have been studying tree rings. In short, tree rings show that Genghis Kahn was born at just the right time. Tree rings are formed in seasonal climates every year, and the width of the tree ring depends upon the temperature that year and the rainfall that year. So, archaeologists studying tree rings in central Asia, they got pine trees in Mongolia and they have pine trees going back for 2,000 years. So, the rings on these pine trees tell them the rain fall and the temperature year by year in Mongolia from the time of Christ up until the 20th century.

LEVITT: So, it’s not that they’re looking at trees that are 2,000 years old. They’re looking at a series of trees and they can tell from the rings when trees that were cut down at different time and then string these together to get you 2,000 years. Is that the method they’re using?

DIAMOND: Exactly. If you cut down a tree today, if that tree is 300 years old, you have a pattern of rings going back to 1700. Then you get a tree that was cut down in 1800 and going back to 1500. You overlap the matched rings, and that way you go back to the time of Christ. What the archaeologists found is that the wettest decades in the last 2,000 years in Mongolia were the three decades around the birth and the childhood of Genghis Kahn. So, what’s the significance of wet years? Well, wet years means that lots of rain, meaning lots of growth of hay for horses — each Mongol in battle needs 10 horses. And then there’s lots of hay for feeding cattle and sheep. So, there’s a population explosion. Another example, the Anasazi in the U.S. Southwest, the most advanced society of Native Americans before Columbus. The Anasazi developed an agricultural society in areas of desert where nobody makes a living by agriculture today. To reconstruct the environment of the Anasazi, a friend of mine, Julio Betancourt and others, recognized that pack rats make nests. And in their nests, they’ll gather the surrounding vegetation. But the nest gets abandoned after about 30 years. The pack rats urinate, the urine has crystals in it, and the crystals eventually harden the nest. So, the nest becomes a time capsule of a few decades with all these bits of plant food. You can radiocarbon-date the time capsule, so in effect, this time capsule tells you what was growing within 20 meters of this nest within 30 years of the year 1118 A.D. And these time capsules show that there was a big drought in the Anasazi area, which was worst in the year 1118, which was also the beginning of the Anasazi abandonment.

LEVITT: Wow. It’s funny because economists tend to be pretty arrogant and think we’re pretty clever and we have great ideas, but whenever I encounter other scientists, I’m always blown away by the insights people have. I think I’ve read all your books. And my single favorite passage is when you write about the Norse Greenland settlement, and I found that part of your book — it was in Collapse — so remarkable because the mistakes that the settlers in Norse Greenland made were so preposterous, but somehow they were incredibly familiar as well, even though this was happening six or seven hundred years ago. Here’s a group of people living in an incredibly difficult environment in Greenland, barely surviving, but they’re so strongly wanting to retain an identity as Europeans that they were making choices that are completely mind-boggling. Could you just tell us a little bit about the circumstances?

DIAMOND: Sure. So, the Vikings from Scandinavia began to spread out say from about the 700, 800s onwards. Eventually, they discovered Greenland. The idea today of settling in Greenland, covered with ice — who on earth would want to settle Greenland? But in fact, Greenland has some fjords that are well protected from sea storms. And particularly when the Vikings arrived around AD 1000, these valleys were great for growing hay, for developing the Norse lifestyle based on herding animals — on cows and sheep and making cheese. So, the Norse had a good lifestyle for several centuries, until it gradually got colder. And as it got colder, there was less hay, but also into Greenland came the Inuit, who were masters of living in frozen environments. You would have thought that the Vikings, when they came across the Inuit would have gone to some effort to make friendly relations with the Inuit, who were there in numbers and had these great boats and had sled dogs. In fact, the first account that we’ve got of the Vikings encountering the Inuit is some Vikings who went rather far north, and they came back and gave report on what they found. And they said “Up north, we found some people and the interesting thing about these people, is that when you stab them, initially, they don’t bleed. And then when you stab them some more, they bleed profusely.” Well, that was the first encounter of the Norse with the Intuit, which is not a great way of establishing good relations with people who are better masters of the environment than were the Norse. So, the Norse made some gross mistakes. They refused to eat fish, which is incredible.

LEVITT: They’re living in Greenland, where essentially there’s nothing but fish, why would they refuse to eat fish?

DIAMOND: Good question. We don’t know. Every archaeologist goes out to Greenland — think this is completely impossible. The main export of Greenland today is fish. The Inuit were nourishing themselves with fish and other things. How on earth could the Vikings have been so stupid that they didn’t eat fish? But every archaeologist goes out there and there’re not fish bones. But we know that people have irrational dietary restrictions. In the United States, nowadays we don’t eat horses and we don’t eat heart and we don’t eat kidney. When I was a graduate student in England I needed to find the cheapest food. So, I ate lots of heart and kidneys and liver, but Americans don’t eat heart and kidneys and liver. There are these irrational prejudices, even irrational prejudices that end up killing people.

LEVITT: What I find so interesting about the stories you wrote about it is that these residents of Greenland were making enormous investments in looking like good Europeans. So, huge churches and following European fashions. And we’re talking about the 13th and 14th century, so it’s not like Europe was really having its finest moment either, but ultimately it seems like their undoing was that it was more important to them to have self-identity as Europeans than to thrive in an environment that was changing and inhospitable and eventually would lead to their doom.

DIAMOND: That’s exactly it. That their identity as Europeans led them to build a cathedral and to devote their limited trade with Norway. So, Greenland Vikings exported walrus tasks to Norway. They didn’t have that many walrus tusks. What are they going to get from Norway? Well, they get some wood, and they get some beer. But what they really get from Norway is bronze bells and stained-glass windows for their cathedrals. Well, what they should have gotten was metal so that they could have armor and spears to fight the Inuit, but no, their identity as Europeans was much more important to them. And in the United States today, I don’t need to name Americans whose identity depends upon doing particular things that are not very bright and are going to doom us, but it’s more important to keep doing these things and to remain blind to what it’s going to do to our society in the next 30 years.

LEVITT: So, you’ve detailed so many examples where societies have destroyed the environmental resources that they needed to survive. And you express surprise about why a society would do this. When I read your books, it seems to me the few examples you have where a society successfully protects their environment in cases where there’s real scarcity, that to me is the miracle. And it seems obvious and inevitable that almost any society faced with scarcity is going to end up destroying the environment around them. That’s what an economist would think. So, am I right in characterizing you as someone who’s surprised when people follow their basic human nature and government and society doesn’t manage to rein that in?

DIAMOND: Nowadays, I’ve gotten used to the fact that societies destroy themselves. But naively, if you don’t know that had happened and you don’t know the details of how it happened, it is counter-intuitive that societies would destroy themselves. And as an example of how counter-intuitive it is, there are lots of archaeologists and anthropologists who do not want to believe that societies destroyed themselves. For example, there are archaeologists who refuse to believe that the Easter Islanders chopped down all the trees on Easter Island. They say, “How on earth could these nice people that I know nowadays, how could their ancestors have been so foolish as to chop down the last tree?” They chopped down the last tree for reasons that Americans and Europeans and Japanese and Australians, so many other people today, are in the process of not just chopping down the last tree, but harvesting the last fish. For example, the most prized fish in Japan is Mediterranean Bluefin Tuna. One big Mediterranean Bluefin Tuna on the Japanese sushi market commands something like a million euros. It’s a huge amount of money. So, you would think that the Japanese would be more determined than anybody else to maintain the stocks in Mediterranean Bluefin Tuna. But in fact, the Japanese sushi market, they’re the ones who have provided the strongest resistance to the sustainable management of Mediterranean Bluefin Tuna. So, those are just a couple of examples of how people do things that are disastrous for them for various reasons. Some people make money on it in the short run. There are all the people today who make money off of fossil fuels, although fossil fuels are disastrous for us in the long run. There are people who do things because of a scramble. They say, “Somebody else is going to eat this fish. Somebody else is going to chop down the tree anyway. I might as well be the person to chop it down and get the benefit of this tree or this last fish.” So, there are a whole lot of reasons why people do foolish things, and it takes somewhat special conditions. Elinor Ostrom, as I recall, won a Nobel prize, who studied the conditions under which people do adopt a long- term perspective, and it takes somewhat special circumstances.

LEVITT: Usually, if you don’t have strong property rights, then it’s almost impossible to defend these resources. But I think the problem, even with strong property rights — as I think about the Easter Island case and just imagine what had happened, somebody has property rights over a set of trees and they’re maybe doing exactly the right thing in managing those properties. But if someone else has already chopped down all their trees and they are stronger militarily, then those people are going to take the trees and make the same mistake they made last time around. I think in a world of scarcity, even when there’s a set of people who are doing things sensibly around environmental management, you always run the risk that a bunch of thugs are going to come in and undo you in a world in which you don’t have a good way to defend what you have. So, I could imagine even if the majority of people were trying to do the right thing, that it only takes the minority of people to undo sensible management practices.

DIAMOND: That’s right. I think implicit in what you’re saying is that it requires a well-controlled society for sustainable practices to prevail universally. Japan during the Tokugawa era, from the 1600s onwards, the Tokugawa shoguns cut-off the trade of Japan and so the Japanese, because their castles were constructed with enormous amounts of wood, the Japanese independently developed sustainable forestry.^[2] They measured the trees. They measured the size, the growth rates of the trees. They manage their forest so well that even today, Japan, a first world country, is about 75-percent covered with forest. So, there are societies that have succeeded in managing their resources well.

LEVITT: I liked the way you put it, where you said that you need a “well-controlled society” to try to handle these collective-action problems. But in general, when people start starving, when things are falling apart, that almost by definition is a situation where you’re unlikely to have a well-controlled society, which I think just must have a very negative feedback loop into the destruction of these environments.

DIAMOND: Indeed, and the Greenland Norse are an example of that. Archaeologists have excavated a farm in what appears to be the last year of the settlement. We infer that the people ate their cattle and they ate their calves. So, they foreclosed the means of having calves next year. And then they eat their dogs. There are dog bones, but the dogs are what they use to go hunting. They are desperate. They’ve cut off the means of surviving into the future.

LEVITT: And yet they still didn’t need the fish.

DIAMOND: Right. They still didn’t eat the fish just as we Americans are not eating horses, kidneys, and hearts.

 You’re listening to People I (Mostly) Admire with Steve Levitt and his conversation with Jared Diamond. After this short break, they’ll return to talk about Jared’s near-death experiences.

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LEVEY: Hey Steve. many months ago, we talked about the number of emails we get for the show. And we said we got about five a day. Well, since we shared that we read every email, we’ve actually started getting a lot more.

LEVITT: A lot more.

LEVEY: Have any of the emails jumped out at you, recently?

LEVITT: I’ll tell you the one idea that really jumps out at me — and it’s got nothing to do with saving the world, but it’s just smart and clever — comes from a guy named Cameron who has been sending us a lot of ideas. And his simple idea is that right outside the baseball hall of fame, they should build another structure. And that would house all of the cheaters from baseball, who happened to be super popular players. But, for various reasons, people feel like because of their rule-breaking, they shouldn’t be inside of the hall of fame. So, a place where people like Barry Bonds and, corked bats and Pete Rose and his gambling. When Cameron mentioned it, it just sounded like a winner to me, because it’s a way to have fun with the idea that baseball has a whole history of cheating. Consumers would love it. And it solves a moral problem that people have struggled with. So, to me, that’s the epitome of a great idea. Simple, to the point. You hear it and you say, “Ah, I wish I had had that idea.”

LEVEY: Maybe it should be called “the Doghouse” because they’re essentially in the doghouse, they got thrown out of the sport.

LEVITT: I love that. That is a fantastic idea, Morgan (ML^laughs) piling, good ideas on top of other good ideas.

LEVEY: I will say too, it’s really exciting to watch a baseball player who’s on steroids. (SL^laughs) I mean, I remember when Mark McGuire was just destroying the home run record. And it was a really fun season. I mean, yes, he did have some chemical assistance, but you know, it could be argued that these people really do advance the sport. they set these maybe unrealistic, but these goals for other players to try top.

LEVITT: Exactly. Breaking all the records in ways that, if you play within the rules, you’ll never achieve. Or people like Pete Rose, who was gambling on baseball and people were very upset about it, but it doesn’t mean he wasn’t an amazing player, and it doesn’t make him any less interesting to future generations. In many ways, the cheaters are maybe more interesting than the people who played it fair. Do you remember when we had Travis Tygart on our show, who is in charge of the U.S. Anti-Doping Commission? That argument didn’t fly with him. 

LEVEY: It’s true. It’s true. Steve, I know that your center at the University of Chicago called R.I.S.C. was on the lookout for new ideas Is that website still available for people?

LEVITT: Absolutely. We have a website it’s R.I.S.C. with a C risc.uchicago.edu/ideas.

LEVITT: We aren’t really looking for ideas about the hall of fame, but look, we take any idea. But what we’re really looking for is people who just have great ideas that in some small way, or hopefully in a big way will make the world a better place.

LEVEY: Sounds great. Well, Cameron, please keep sharing your ideas with us. We’ve been loving them. If you have an idea, you can reach us at our email address, which is pima@freakonomics.com. That’s P I M A @freakonomics.com. It’s an acronym for our show. Steve and I read every email that’s sent, and we look forward to reading.

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LEVITT: So, people listening to you might think that you are very much a creature of the mind, but one thing that’s very different about you than many intellectuals is that you’ve spent time in crazy places. New Guinea is where you do your field research. I imagine you’ve gotten into all sorts of predicaments in the Highlands of New Guinea, haven’t you?

DIAMOND: I’ve made something like 32 trips to New Guinea, I began in 1964 and everything possible has gone wrong. I can make a long list of ways that I nearly lost my life. So, there was a boat accident. There’ve been multiple near plane accidents. There was a car accident. I’ve been in remote areas where we didn’t think the helicopter would come back to pick us up. I made the mistake of getting into a motorized canoe connecting the third main airport of New Guinea with the mainland. It was only a distance about 15 miles, but the drivers of the canoe were imprudent young men who raced off, gunned the motor at high speed into waves. Those of us in the canoe shouted to them to slow down, but they didn’t. The canoe then overturned. We clung to the bottom of the canoe. It was clear that we were not going to be able to survive the night. We were picked up 15 minutes before sunset by two sailing canoes, one of which then tipped over because it was overloaded. We heard them screaming. There was nothing we could do about it because we were overloaded. So, we survived. The other three did not. That was my closest call.

LEVITT: Wow. Let me ask you about the jungle. So, what do you do when you get lost in the jungle?

DIAMOND: A flip answer is that’s it, if you’re in a remote area. In my case, the most serious occasion of getting lost in the jungle was when I was dropped by helicopter in an uninhabited mountain range with a New Guinean. The New Guinean made a trail up the mountain so that I could discover mountain birds. On Sunday when the New Guinean, for religious reasons, stayed in camp, I went up the mountain to the end of the trail, and I thought I would see if I can get a little further. So, I just pushed on another 20 feet. I turned around and I could not see the trail.  So, I looked at the place where I was, I went to off on various radiuses for short distances, keeping an eye on where I had started out. And on one of those radiuses I hit the end of the trail. If I had not seen the trail, I was going to be overnighting on the mountain, and that would probably have been fatal.

 LEVITT: Now, I can’t say that my own economic research has exposed me to a lot of dangers the way your ornithology research has. But listening to your stories does make me recall when I was a young scholar and I would do ride-alongs with the police on the South Side of Chicago. And then the first time I did a ride along, I walked up to the officers and I noticed that they were wearing bulletproof vests. And I asked if I should wear one as well. And they said, “Well, you probably should, but unless you brought your own, you won’t be wearing one today.” So, we set off into the car. And at first, they would tell me to stay in the car, but I didn’t come on a police ride along to stay in the car. So, I negotiated and, by the end of the night there was a domestic violence call and we could hear yelling and screaming coming from up these stairs. And I couldn’t believe it, but they literally shoved me up the stairs first. So, I’m running up the stairs into this chaos. And I’m wondering what the man and the woman thought when some white professor with big glasses and khaki pants came pounding up the stairs into their house. Now, I was shortly followed by two police officers, but I think actually the fighting stopped very quickly as they tried to assess what in the world I was doing in their house until they saw the police right behind me. Nothing like overturned canoes, but still for me, a little bit of excitement.

 DIAMOND: That does sound exciting. It took 15 years and that near fatal boat accident for me to learn to be ultra-careful. But my attitude that I learned from that accident is what I call constructive paranoia, that is thinking of everything that can go wrong and planning for it. I’ve had enough of these experiences that — once-in-the-lifetime happening that can end, or that can change your life. So, that attitude of constructive paranoia has permeated my outlook on life.

 LEVITT: How is that consistent with making 30-something trips to New Guinea? Most people who have that trait tend to stay very close to home.

 DIAMOND: A short answer is New Guinea is the most fascinating place in the world. The only disadvantage of working in New Guinea is that after New Guinea, the rest of the world is gray and boring. It is just so interesting and beautiful. New Guinea birds are so fascinating. New Guineans themselves are so different and distinctive, and interesting, and curious. New Guinean languages, there are a thousand of them. That’s why I go to New Guinea.

 LEVITT: Thinking about your experiences remind me of another experience, which can’t compare to yours, but in my little world is about as bad as things get. I take my undergraduate students on field trips. And one of the places where we go is to the Cook County jail. And usually these are pretty uneventful trips. But once our guide asked if we wanted to meet some of the inmates. And of course, I said, “Sure.” And much to my surprise, she opened up a locked door and I and my students and a single guard entered a pod that had a few dozen inmates in a common area. And then she locked the door behind us. And the inmates stopped what they were doing and they all came towards us, not in a threatening way, but still, it was intimidating, these 24 inmates coming towards myself and my students, half of whom were female. And we meet in the middle of this room. And I needed some kind of an ice breaker and in the heat of the moment, the best I could come up with to the first gentlemen who came close to us, I just said, “What are you in for?” And he responded, “first-degree murder.” And that was definitely a conversation stopper. Eventually, I collected my wits and we ended up having a really amazing conversation. And, at least my experience is, here in the jail or anywhere else is how much alike people are. So, wherever I’ve gone in the world was India or Argentina or the jail. It’s surprising to me always how similar people are. Has that been your experience as well?

DIAMOND: Yes, I would say that’s the case. I have excellent relationships with the vast majority of New Guineans. Why? Because they’re really interesting and curious and smart. And also they understand birds, and it’s the case that I come there to study birds.

LEVITT: You told one anecdote in a book, I can’t remember which one, which stuck with me, even though it’s been years — you mentioned that one of your best New Guinean assistants had suddenly quit because he had to go eat his son-in-law, who had suddenly died. What’s that all about?

DIAMOND: It’s not that he quit to eat his son-in-law. He quit to eat, I think, one of the two forearms of his prospective son-in-law. This was an area where cannibalism was still going on. It was not what’s called exocannibalism, namely eating your dead enemies whom you’ve killed. It’s what’s called endocannibalism, eating your dead relatives, which is something that is done out of respect. I mean, there’s no way that in these areas of New Guinea, you would not eat your dead relative, just as there’s no way that if someone close to you died, you would leave them on the ground and you would not bury them. And in this case, a runner from the village came and brought the news that the young man had died a couple of days ago. And so, my man quit without telling me the reason. But then other New Guineans in camp said the reason he quit is that the young man who made the down payment on his daughter had died and his relationship meant that he was entitled to eat a particular part of the body, I think the forearm. Making this somewhat unpleasant is that the death had not occurred the day before, but the death had occurred several days ago. This was in a hot climate. So, I will spare you the details of how the body is eaten.

LEVITT: And is this a practice that served at one point a practical function or is this purely ceremonial?

DIAMOND: I think there’s a practical explanation for it, although it’s certainly not one that the people doing it would give. If you look around the world at where there is cannibalism, there’s not cannibalism in Africa. Why not? Because they are big game animals in Africa. The parts of the world where cannibalism is practiced, are areas by and large where there are not large game animals, where people are starved for protein. And that’s why it makes some sense to eat humans as the largest animal available.

LEVITT: So, you think this practice of endocannibalism, it started really from a lack of protein and an avoidance of waste, and it’s evolved into a custom? That’s your take on it?

DIAMOND: That would be my take on it. I would say that’s the ultimate reason. No New Guinean would ever say, “We do it because we’re starved for protein.” They would say “We are doing it to honor our relatives.” But why is it that I, Jared Diamond, haven’t also honored my relatives by endocannibalism? I live in a society where there are other sources of protein, and there are other ways that we honor our relatives.  

LEVITT:  In December 2020, you wrote a piece that surprised me. You argued that as tragic as the Covid pandemic was, you believed that the international community would work together to beat it. And that this would have positive long-term benefits because it would catalyze global cooperation on other more complex issues like climate change. That was a year ago. Do you still carry that optimism?

DIAMOND: Yes, I would say I’m cautiously optimistic. Partly, if I weren’t optimistic, I would have no justification for continuing to live. But also, there are hopeful signs. In the case of Covid, there is at least discussion, and actually some acts towards sending the vaccines overseas. Covid is a potent teacher. New Zealand and Australia have given up on trying to exclude Covid because they realized that they can’t exclude Covid. They’re on a planet with other people. They’re going to have to deal with Covid.

LEVITT: How could New Zealand and Australia have taken so long to figure this out? How is it that world leaders could think that there was some way that New Zealand would shut itself off from the rest of the world forever when it came to Covid? I mean, it doesn’t make any sense to me. 

DIAMOND: It doesn’t seem so bad to me. New Zealand has had a realistic chance because New Zealand could cut itself off from the outside world, could survive without tourism, could survive with a minimum of trade, and could realistically hope that they could survive in isolation for a year or so until the Covid epidemic is over. Australia being even bigger — the hope for Australia was realistic. The Australian government has left lots of Australians overseas. But now New Zealand has realized that they’re not going to be able to eliminate Covid. They got to deal with vaccines, but I hope that this will be a lesson for the world, that no country will be safe until the whole world is safe. And once the world has learned that lesson for Covid, maybe — this is my hope — we will generalize and we will realize that we Americans cannot reduce carbon dioxide levels just over the United States. The atmosphere is mixed just as microbes are mixed. And so, my hope is that we’ll learn to deal with the real threats of climate change and resource depletion, which are far more serious threats than the bagatelle of Covid.

LEVITT: I’m struck by the fact that you used the word hope, because it seems to me that that really is just a hope and reading your books, I mean, you know as much about human civilization as anyone. Do you actually think there’s a possibility that there will be global cooperation short of some kind of true nightmare scenario already unfolding? It just seems to me — you know, obviously we’d all like that. Sensible people would like to agree on it. But I just see no real precedent for global action about a problem that is complex, the biggest costs are far in the future, and that’s really expensive, right? It’s not cheap compared to many other things, like things we’ve had success on, like C.F.C.s. It’s not cheap at all to deal with climate change. So, I’m extremely negative when it comes to my expectations about what governments will do about climate change. In your heart, do you think that’s actually a realistic scenario?

DIAMOND: Yes, I think it’s possible. It’s not certain. It’s not a slam dunk. When people, as you asked me, “Jared, are you optimistic or pessimistic?” I would say I’m cautiously optimistic. I see the chances as at least 51 percent that we’ll have a happy ending and only 49 percent we’ll have a sad ending. I’ve seen things within the last 20 years — hopeful signs that have developed to my surprise. Twenty years ago, I said that big international companies are the most evil destructive forces in the world.  And in the last 20 years, partly with whom I work with — I’m on the board of directors of World Wildlife Fund, and I was on the board of directors of Conservation International — we work a lot with big international companies, and I’ve seen over the last couple of decades, these companies developing more and more sustainable policies. Example, Walmart, of all companies, even oil companies in some cases. Unilever. Partly because the C.E.O.s recognize that the survival of their own children is going to depend upon a sustainable world. Also, it’s the case that big international businesses realize that their profits depend upon a sustainable world. And another thing that makes me optimistic is the change in attitudes even within the United States. Today, the majority of Americans do believe in climate change and do believe that climate change is caused by human action. That’s not the case of the majority of members of Congress, but it is the case that the majority of intelligent Americans do believe in the reality of climate change. So, I’m cautiously optimistic. I think we have a more than 50-percent chance of a happy ending.

LEVITT:  So, if you had to guess, when will human society peak? Things have been more or less getting better for at least the last 10 or 11,000 years. Do you think we have another 11,000 good years ahead of us?

DIAMOND: Oh, good heavens, that all depends. At the rate that things are going now, we’ve got about another 30 years left to get onto a sustainable course. or we’ve lost our chance and we’ll have depleted irreversibly essential resources as far as fisheries, topsoil, and water.

LEVITT: You’re not making me very — very optimistic about things. I’m amazed that you hold these views and feel optimistic.

DIAMOND: There’s a lot of uncertainty, and in this uncertainty, if one’s going to stay alive and not commit suicide, one has to have optimism. Why have children, if you’re not optimistic? One has to have cautious optimism.

LEVITT: I’m curious. Why did you start writing popular books?

DIAMOND: There were three reasons why I started writing popular books. In the 1980s, after devoting my, professional career to gallbladders, I was interested in lots of other things from my childhood. And in the 1980s, I began writing articles for popular science magazines, for Natural History, for Discover Magazine. Writing the popular articles gave me the opportunity to learn about all those fascinating things other than gallbladders and to devote time to them. Then in 1985, I was awarded one of these MacArthur foundation fellowships. You have five-year fellowship with no strings attached. You can do anything you want. So, it sounds wonderful. The result was the most severe depression of my adult life. So, I told myself, “Jared, you’ve been wasting your life on gallbladders. You haven’t been fulfilling your potential. The MacArthur grant means that people think that you can do more valuable things than gallbladders and even more valuable thing than New Guinea birds.” So, that was one precipitant. And the other precipitant was that my wife and I — our twin sons were born half a year short of my 50th birthday. That was in the year 1987. When they were born, I started doing the numbers. I was then 49 years old. People talked about the end of the Amazon rainforest, all going to be chopped down by the year 2050. I’m not going to be alive then. But my kids will be 63 years old in the year 2050. They won’t even be at the peak of their life. Because I’m now 84. In retrospect, I would say the best years of my life were my seventies. But their future, the future of Max and Joshua, is not going to depend upon gallbladders. It’s going to depend upon climate change and resource depletion. And Jared, what are you going to do about that? So, that was what motivated me to start writing books for the general public, to learn about science and about the real world, and to motivate the general public to start dealing with the problems that threaten the future of my kids and your kids. And eventually that was why I closed my gallbladder lab and moved over to the geography department at U.C.L.A.

LEVITT: I wish I could give such a noble reason for why Steven Dubner and I wrote Freakonomics because the simple fact is that we just wrote it for the money. The publishers offered us a lot of money to write a book and we didn’t actually think anyone would read it. And in fact, I think that was valuable to us because it freed us up. I thought you were going to say that you wrote books because you had this burning desire inside of you to be read or something, but it really sounds like it was much more instrumental, much more that you hope to change the path of humanity, not because you had any particular desire to be famous.

DIAMOND: I enjoy writing books. I enjoy learning. I enjoy understanding. I enjoy helping other people to understand. And I hope it will improve the chances of my sons’ world being a decent world.

LEVITT: So, you said that your best decade was your seventies and you’re 84 now. And I think the vitality and the curiosity you have is really a role model. I would love my seventies to be my best decade. Do you have advice for people about how you stay so young at heart and connected and curious as you’ve aged?

DIAMOND: I’m interested in lots of things. And if I lived to 170, I wouldn’t do all the things that I would love to do. When I was four years old, I started keeping a notebook. I learned my first foreign language when I was 11 years old. I’ve learned 13 languages. If I were not writing a book now, well, Johann Sebastian Bach wrote 220 cantatas, and I play the organ. I would like to get to know those cantatas, take notes on them, get to understand them. There are just so many wonderful things to do in the world. I still enjoy doing all these things and I don’t see an end in sight until my body gives way.  

LEVITT: Hopefully you’ll have at least two or three more decades to both write books and become the world’s expert on Bach’s cantatas.

DIAMOND: I’ll settle for another decade or two.

*      *      *

I often ask people, especially older people, what period of their life they’ve enjoyed the most. How would you answer that question? For me, it was college. But interestingly, almost no one else I’ve asked shares that view. A surprising number of people like Jared Diamond say their best years were in their 60s and 70s. I never would have imagined that, but if there’s ever been a reason to be optimistic, it’s knowing that maybe our best years are still ahead of us. I better start exercising so I live that long.

People I (Mostly) Admire is part of the Freakonomics Radio Network, which also includes Freakonomics Radio, No Stupid Questions, and Freakonomics M.D. This show is produced by Stitcher and Renbud Radio. Morgan Levey is our producer and Jasmin Klinger is our engineer. We had help on this episode from Alina Kulman. Our staff also includes Alison Craiglow, Greg Rippin, Emma Tyrrell, Lyric Bowditch, Jacob Clemente, and Stephen Dubner. Theme music composed by Luis Guerra. To listen ad-free, subscribe to Stitcher Premium. We can be reached at pima@freakonomics.com. That’s P-I-M-A@freakonomics.com. Thanks for listening.

DIAMOND: They would never eat me. There are precise rules about who eats who, and what part of the person gets eaten.

 

^[1] https:www.jneurosci.org/content/36/7/2077

^[2] https:storymaps.arcgis.com/stories/e250ea98bbfe491b96d51ad94a14437f