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Why Rome actually fell: plagues, slavery, & ice age — Kyle Harper
41 segments available
800 years before the Black Death, the very same bacteria ravaged Rome, killing 60%+ of the population in many areas. Also, back-to-back volcanic eruptions caused a mini Ice Age, leaving Rome devastated by famine and disease. I chatted with historian Kyle Harper about this and much else: * Rome as a massive slave society * Why humans are more disease-prone than other animals * How agriculture made us physically smaller (Caesar at 5'5" was considered tall) 𝐄𝐏𝐈𝐒𝐎𝐃𝐄 𝐋𝐈𝐍𝐊𝐒 * Transcript: https://www.dwarkesh.com/p/kyle-harper * Apple Podcasts: https://podcasts.apple.com/us/podcast/dwarkesh-podcast/id1516093381?i=1000704767817 * Spotify: https://open.spotify.com/episode/5LhE123eOtQoOm0IPusEiT?si=4d7d8b25374a4f92 𝐒𝐏𝐎𝐍𝐒𝐎𝐑𝐒 * WorkOS makes it easy to become enterprise-ready. They have APIs for all the most common enterprise requirements—things like authentication, permissions, and encryption—so you can quickly plug them in and get back to building your core product. If you want to make your product enterprise-ready, join companies like Cursor, Perplexity and OpenAI, and head to https://workos.com * Scale’s Data Foundry gives major AI labs access to high-quality data to fuel post-training, including advanced reasoning capabilities. If you’re an AI researcher or engineer, learn how Scale’s Data Foundry and research lab, SEAL, can help you go beyond the current frontier of capabilities at https://scale.com/dwarkesh To sponsor a future episode, visit https://dwarkesh.com/advertise. 𝐊𝐘𝐋𝐄'𝐒 𝐁𝐎𝐎𝐊𝐒 * The Fate of Rome: https://www.amazon.com/Fate-Rome-Climate-Disease-Princeton/dp/0691166838 * Plagues upon the Earth: https://www.amazon.com/Plagues-upon-Earth-Princeton-Economic/dp/069119212X * Slavery in the Late Roman World: https://www.amazon.com/Slavery-Late-Roman-World-275-425/dp/0521198615 I highly recommend all of these. Kyle is also working on a new book called The Last Animal. Stay tuned for the release! 𝐓𝐈𝐌𝐄𝐒𝐓𝐀𝐌𝐏𝐒 00:00:00 - Plague's impact on Rome's collapse 00:07:08 - Rome’s little Ice Age 00:12:35 - Why did progress stall in Rome’s Golden Age? 00:24:39 - Slavery in Rome 00:37:06 - Was agriculture a mistake? 00:48:26 - Disease’s impact on cognitive function 01:00:30 - Plague in India and Central Asia 01:06:00 - The next pandemic 01:17:32 - How Kyle uses LLMs 01:19:35 - De-extinction of lost species
Segments Timeline
The Role of Disease in History
Kyle Harper discusses the profound impact of diseases, particularly the bubonic plague, on human history. He highlights how these pandemics have caused significant population declines, shaping societies and their trajectories. Harper emphasizes the importance of understanding these historical events through the lens of biology, economics, and climate, as they are interconnected in explaining the collapse of civilizations like Rome.
"Today, I have the pleasure of chatting with Kyle Harper, who is a professor and provost emeritus at the University of Oklahoma, and the author of some really interesting books: The Fate of Rome, ..."
Environmental Factors in Rome's Decline
In this segment, Harper explains how environmental factors, particularly climate change and disease, contributed to the transformation of the Roman Empire. He notes the drastic population decline in Rome from its peak and discusses the significant mortality rates caused by pandemics like the plague of Justinian and the Black Death, which reshaped the demographic landscape of the empire.
"One of the things you discuss in the book is that the collapse of the Roman Empire was a result of this one particular event. The period that I normally work on is from the High Roman Empire, the..."
Counterfactuals of Roman Survival
Harper explores the idea of counterfactual history, questioning whether the Roman Empire could have survived longer had it not faced the dual shocks of plague and climate change. He draws parallels with other dynasties, suggesting that a Mediterranean core of the empire might have persisted if not for these catastrophic events, highlighting the fragility of historical trajectories.
"death rates, temporarily, that are just orders of magnitude beyond what we're accustomed to. Even in these ancient societies, the reason why these were so shocking, in a world where the death ra..."
Apocalyptic Thinking in Crisis
This segment delves into how people in the sixth and seventh centuries interpreted the catastrophic events of their time. Harper discusses the rise of apocalyptic thought, particularly within the burgeoning Christian faith, as individuals sought to make sense of widespread death and suffering without the benefit of modern scientific understanding.
"there were these two previous other big pandemics. The empire still survives. I think Will Durant had this quote that the Roman Empire fell for longer than most empires have lasted. Do you think ..."
Climate Change and the Roman World
Harper explains the significant climate changes that occurred during the Roman period, particularly due to volcanic eruptions. He discusses how these eruptions led to a cooling climate that adversely affected agriculture, compounding the effects of plague and famine. This segment highlights the interconnectedness of environmental factors and societal collapse.
"could have had another turn as the thing we kind of mean when we say the Roman Empire: this pan-Mediterranean, powerful, urbanized empire. Yeah. Okay, one of the things I found really interesting..."
The Economic Landscape of Rome
In this segment, Harper paints a picture of the Roman economy during its peak, discussing the complexities of trade and productivity. He notes the advancements in financial markets and trade networks, yet emphasizes the limitations of technology and scientific understanding that ultimately hindered sustained economic growth.
"eruptions. Volcanoes are a very powerful short-term climate forcing mechanism. They eject sulfur into the stratosphere. It aerosolizes and creates a reflective shield that scatters the radiation..."
Why Rome Didn't Experience an Industrial Revolution
Harper addresses the question of why the Roman economy did not catalyze an industrial revolution despite its advanced state. He attributes this to a lack of technological innovation and scientific inquiry, explaining how the absence of a systematic approach to knowledge and experimentation stifled potential advancements.
"which is always kind of there. You mentioned that Christianity is eschatological. It is, yes, fundamentally, but that comes out in different ways with different emphases in different time period..."
The Role of Science in Economic Growth
This segment discusses the importance of science and empirical knowledge in driving economic progress. Harper contrasts the Roman approach to knowledge with later developments in Europe, emphasizing the need for a culture that fosters scientific inquiry and innovation to achieve sustained economic growth.
"In some ways it was so precocious for its time period, and it seems not utterly impossible. The Roman world is still a pre-industrial economy so agriculture is the dominant sector. The majority ..."
The Importance of Interdisciplinary Knowledge
Harper concludes by discussing the necessity of integrating various fields of knowledge, such as science, engineering, and economics, to foster innovation. He reflects on how the lack of collaboration between different disciplines in ancient Rome limited their potential for technological advancement and economic transformation.
"and the 17th century language for that is useful knowledge. That is something that doesn't ever get wired together in the Roman Empire. There are tinkerers and engineers, but they're not talking..."
The Lost Library of Herculaneum
Harper expresses excitement about the potential discoveries from the library buried by Mount Vesuvius, which could double the known classical texts. He reflects on the history of mathematics after Euclid and the stagnation of scientific progress in ancient Rome, pondering the reasons behind the lack of sustained advancements.
"positive feedbacks. What the Romans don't have is that. What the Romans do have is the kind of specialization, and now that we look for it, it's there. When you look at food processing, which is..."
Understanding Slavery in Ancient Rome
Kyle Harper paints a vivid picture of slavery as a foundational institution in Roman society, detailing how conquests led to a reliance on slave labor in various economic sectors. He emphasizes the dual necessity of supply and demand for slaves and the institutional mechanisms that sustained this exploitative system.
"Let's turn to another one of your books, the one about slavery in the Roman world. I did not realize before I read that one how much Rome was a slave society. I guess that just isn't a salient t..."
The Ideology of Roman Slavery
Harper explores the ideological justifications for slavery in ancient Rome, noting that it was not racially based but rather rooted in property laws and status. He discusses the absence of a significant abolitionist movement and the complex psychological dimensions of slavery, including how societal norms perpetuated the system.
"the institutions, the presence of markets where you can take labor and turn it into profit that's the most important element. One of the things I find interesting is in the age of colonization we..."
The Sustainability of Roman Slavery
In this segment, Harper examines the surprising sustainability of slavery in Rome despite a large enslaved population. He discusses the elaborate systems of repression and incentives that prevented widespread revolts, highlighting the psychological and social structures that maintained control over enslaved individuals.
"and convince themselves that it's okay. I hope your next book about The Last Animal discusses the potential parallels with factory farming. There's some... there's a pretty gruesome chapter, I'll..."
Gladiator: A Historical Perspective
Harper critiques the historical accuracy of the film Gladiator, acknowledging its entertainment value while noting its portrayal of the exploitative nature of slavery. He discusses the film's strengths in depicting the diverse backgrounds of slaves and the brutal realities of the Roman slave system.
"there would've been more opportunities for positive feedback loops. The way the argument's usually made is just that the Romans got rich without really thinking about productivity. They just wan..."
Agriculture: A Double-Edged Sword
Harper reflects on the transition from foraging to agriculture, discussing its profound impacts on human health, diet, and social structures. He contrasts the varied diets of hunter-gatherers with the monotonous diets of sedentary farmers, emphasizing how this shift contributed to the rise of infectious diseases and altered human lifestyles.
"Rome. We can get back to your most recent book about human history and plagues. What do you make of the general argument that people have often made that we were living in a sort of Eden before a..."
Infectious Diseases and Human Evolution
Harper argues that the burden of infectious diseases increased over time, particularly during the Roman Empire. He discusses how the agricultural lifestyle created conditions that favored the spread of diseases, impacting human health and population dynamics throughout history.
"that they had were seriously burdensome, they sucked, and probably most people died of infectious disease. Malaria is a really old disease. Lots of diseases existed in the Pleistocene, in our Pa..."
Cultural Evolution and Disease
In this segment, Harper examines the role of cultural evolution in shaping human societies and their relationship with infectious diseases. He draws parallels between early agriculturalists and modern populations, highlighting how exposure to pathogens influenced societal success and population dynamics.
"these thousands and thousands of years, the diseases suffered by people by the time of the Roman Empire are absolutely much worse than what had been the case in Stone Age times. James Scott has a..."
Unintended Consequences of Agriculture
Harper discusses the unintended consequences of the agricultural revolution, emphasizing that no single generation made the choice to transition from foraging to farming. He highlights how this gradual process led to significant changes in human lifestyles, health, and societal structures.
"we become sedentary farmers with basically torturous dentistry and die by diarrhea? This happens over thousands of years through an evolutionary process where nobody can... It's a story of unint..."
Fertility and Lifestyle Differences
This segment focuses on the differences in fertility rates between foragers and sedentary farmers. Harper explains how the nomadic lifestyle of hunter-gatherers influenced reproductive patterns, contrasting it with the more stable but demanding life of agricultural societies.
"themselves and grow and reproduce, whereas farmers per unit of land can extract such higher rates of energy that then can be, through photosynthesis, turned into edible sugars that we can metaboli..."
Cognitive Function and Disease Burden
Harper discusses the impact of diseases on cognitive functioning throughout history. He connects malnutrition and infectious diseases to lower average IQ levels in pre-industrial populations, suggesting that health burdens significantly affected human development and intelligence.
"Yeah. The point you made about fertility is interesting. I vaguely remember reading that it's not just the fact that the energy density is lower, it's that you're also moving around a lot. Becau..."
Physiological Changes Over Time
In this segment, Harper outlines the physiological changes in human populations over the last 250 years, linking improved nutrition and reduced disease burdens to increased average height and cognitive abilities. He argues that these changes reflect significant advancements in public health and living conditions.
"One thing I'm really curious about is what effect these diseases through history have had on the cognitive functioning of people. You discuss this in the chapter about more recent history of the..."
The Paradox of Genius in History
Harper explores the coexistence of genius and poor public health in historical contexts. He discusses how remarkable individuals emerged despite the overall lower cognitive abilities of their populations, highlighting the complexities of human development during the pre-industrial era.
"this improves people's cognitive abilities. People are smarter. May not feel like it—I think it has rapidly leveled off—but people are more intelligent today than they were 100 years ago. Their ..."
Cultural Evolution and Public Health
This segment examines the challenges of public health improvements throughout history. Harper discusses the slow progress in understanding and implementing effective health measures, emphasizing the role of cultural evolution in addressing complex health issues.
"the 17th, 18th century, in particular, is it's sort of this between period where you have the pre-industrial and the modern that are still mixed together in these really interesting ways. The ex..."
Vaccination: A Hard-Won Achievement
Harper highlights the historical challenges of developing vaccines as a crucial public health achievement. He discusses the lengthy process of discovering vaccination methods and the importance of cultural knowledge in advancing public health practices.
"When I had Joseph Henrich on, one of the things he discusses is if you look at... cultural evolution has figured out some remarkable things. If you look at the cuisines of different cultures, ap..."
The Complexity of Cultural Knowledge
In this final segment, Harper reflects on the complexities of cultural knowledge and its evolution. He discusses how societies have historically solved problems through trial and error, leading to significant advancements in health and nutrition, while also acknowledging the challenges that remain.
"Vaccination's the most important one and it took forever to find the first vaccine. It took this huge period of all kinds of weird trial and error, like inoculation with the actual smallpox, whi..."
Cultural Evolution and Knowledge Storage
Harper emphasizes the importance of cultural evolution in storing knowledge about disease prevention and treatment. He reflects on how past discoveries, like those of Jenner and Pasteur, have shaped modern medicine, allowing society to build on previous knowledge without having to rediscover it. This segment underscores the significance of collective learning in combating diseases.
"stored in the library of cultural evolution. It's known, we don't even think about it most of the time until it's controversial. What a blessing to live after people like Jenner and Pasteur who ..."
The Mystery of Scurvy's Discovery
In this segment, Harper explores the delayed understanding of scurvy and the complexities involved in discovering its cure. He discusses the challenges of identifying the right sources of vitamin C and the historical context of knowledge loss and rediscovery, illustrating the intricate nature of scientific progress.
"that the kinds of things that Henrich discusses forager societies having figured out. Literally, there's this 10-step process for how to process a certain kind of bean so that you don't get cyanid..."
Plague's Path to India
Harper delves into the historical presence of the plague in India, discussing the evidence of its existence during the 17th century and the uncertainties surrounding its earlier outbreaks. He examines the connections between India and Central Asia, highlighting the complexities of plague transmission and the historical context of disease spread.
"certain plateau, then the discoveries come really fast. They become systematic, and they become more fundamental. But it was really hard to get there. Not that many societies really scaled it, no..."
Understanding Plague's Historical Impact
This segment focuses on the historical implications of the plague in India and its potential routes of transmission to Rome. Harper discusses the challenges historians face in tracing the plague's history and the significance of understanding its spread through trade networks, emphasizing the interconnectedness of ancient civilizations.
"plague bacillus is discovered by Alexander Yersin. It's called Yersinia pestis in his honor. A Japanese scientist finds it exactly the same time. Gets left out of the nomenclature. It’s a special..."
Challenges in Ancient DNA Research
Harper addresses the difficulties in studying ancient DNA, particularly in India, and the factors that affect the preservation of genetic material. He explains the importance of ongoing research and the need for more archaeological efforts to uncover historical evidence of diseases like Yersinia pestis.
"enzootic, its natural animal reservoir is the Tian Shan Mountains where China, Kazakhstan, and Kyrgyzstan meet, and we can actually identify a pretty small region where the pandemic lineage come..."
Synthetic Biology and Future Pandemics
In this segment, Harper discusses the implications of synthetic biology in creating new diseases and the potential risks associated with engineered pathogens. He reflects on the evolutionary pressures that shape disease transmission and the unpredictable nature of infectious diseases, emphasizing the need for vigilance in the face of future pandemics.
"Huh. I know the way we found that the Yersinia pestis existed in these Yamnaya 4,500 years ago is by... Didn't they just find the...? I don't know how, but if you can figure that out, why can't ..."
The Unique Nature of the Plague
Harper explains the peculiar characteristics of the plague as a vector-borne disease and its evolutionary adaptations. He discusses how the plague's transmission through fleas allows it to evade certain evolutionary constraints, making it a particularly dangerous pathogen.
"And just to be clear for the context- Ancient, ancient, ancient. Okay, going forward to the future a little bit, speaking of future technology, maybe the one that's more relevant than AI is synthe..."
Understanding Pathogen Evolution
This segment dives into the evolutionary dynamics of pathogens, particularly the plague. Harper discusses the balance pathogens must strike between virulence and transmissibility, and how the unique nature of the plague complicates our understanding of infectious diseases.
"seems to sort of evade some of these evolutionary constraints, and it's worth saying what these are. A pathogen is a disease-causing organism, a microbe, usually a virus or a bacterium, but also..."
The Plague's Historical Cycles
Harper reflects on the historical cycles of the plague and the factors that contribute to its reemergence. He discusses the complexities of understanding when the plague circulates in human populations and the various ecological and evolutionary factors that influence its outbreaks.
"really good and really creative, unfortunately for us. The tricks that they find to hide inside your immune system or to fake it out are really wild. There are two reasons why plague is so weird, ..."
The Unpredictability of Infectious Diseases
In this segment, Harper emphasizes the unpredictable nature of infectious diseases and the challenges they pose to public health. He discusses the importance of understanding the ecological and evolutionary principles that govern disease emergence and the need for preparedness against future outbreaks.
"It's very well adapted to transmit, particularly by fleas, but we think also maybe by lice and other biting organisms, but really by fleas. It's really good at transmitting by fleas. That's evolu..."
The Role of Evolution in Disease
Harper concludes by discussing the broader implications of evolution in the context of infectious diseases. He highlights the creative and unpredictable nature of evolution, emphasizing the need for ongoing research and vigilance in understanding and combating pathogens.
"evolutionary history. The plague just wants to infect rodents. Of course, I'm... it's not really wanting to do this. The plague makes a living, it survives out there in burrowing rodent colonies. ..."
The Unpredictability of Infectious Diseases
Kyle Harper discusses the unpredictable nature of infectious diseases, highlighting tuberculosis as a significant example. He explains how this bacterial pathogen operates and the challenges it poses, particularly for vulnerable populations. Harper warns of future pandemics and emphasizes the need to be cautious about emerging diseases that could exploit human weaknesses.
"one's kind of an outlier, but infectious disease is always kind of like that. Tuberculosis has probably killed more people maybe than any other infectious disease. It's like this horrible diseas..."
Evolution's Creative Pathogens
In this segment, Harper elaborates on the evolutionary history of pathogens and their ability to adapt and exploit human vulnerabilities. He discusses how the characteristics of diseases, like COVID-19, can complicate containment efforts. This highlights the importance of understanding the evolutionary dynamics of infectious diseases as we prepare for future outbreaks.
"It's not just transmissibility and virulence. Those are like two really basic parameters. When you look at even COVID-19, part of what made it insidious is it just has just the right parameters t..."
AI in Historical Research
Kyle Harper shares his experiences with AI tools like Deep Research in historical research. He explains how these tools assist in synthesizing literature and generating insights, while still emphasizing the irreplaceable role of human creativity and synthesis in historical analysis. Harper reflects on the evolving relationship between AI and research methodologies.
"weakness we give it. It's because there are billions and billions and billions of microbes in this room. I don't know how many tens to hundreds millions of species of microbes are in this room. ..."
The Ethics of De-Extinction
Harper addresses the ethical considerations surrounding de-extinction technologies. He argues that while it may be scientifically feasible to bring back extinct species, the ecological context is crucial. The segment emphasizes the importance of preserving ecosystems and biodiversity, rather than merely resurrecting species without their natural habitats.
"obviously more and more reliable really quickly. But I think it hasn't yet... in some of the deeper research, it's not the equal of humans yet, and then in the synthesis, it's really not. There's..."
Legacy of Human Impact on Biodiversity
In the closing thoughts, Harper reflects on the long-lasting impact humans have on biodiversity and ecosystems. He stresses the importance of making informed choices today to ensure a vibrant future for living systems. This segment serves as a poignant reminder of our responsibility towards the environment and the legacy we leave behind.
"It can sometimes be very hard to recognize that in our individual lives, but collectively, it will absolutely be part of our forever legacy on Earth. We need to think very carefully about the ch..."