为什么Leonardo是破坏者、Gutenberg破产了，而佛罗伦萨很古怪——Ada Palmer

Today I’m chatting with Ada Palmer, who’s a Renaissance historian, novelist, and composer based at the University of Chicago. Today we’re discussing your book, Inventing the Renaissance. Ada, thanks for coming on the podcast. I’ve been looking forward to it.

First question: In this period—late 15th century, early 16th century—in Italy, you’ve got all these different republics: Venice, Florence, Genoa. That seems unusual both for the time period and for the place.

One of the big reasons that the Italian city republics are clustered in Italy is that when the Roman Empire dissolved in the West, individual cities then needed to self-govern. This is true all across Europe. Those individual cities could no longer get the centralized Roman government to oversee supply routes or keep the roads free of bandits.

You could no longer import and export goods at scale. You could no longer rely on central infrastructure. You had to support things yourself. Larger, wealthier towns were able to make this transition because they could support themselves from the local resources and the farms attached to them.

The larger, wealthier towns surrounded by good agricultural land were more successful at converting over. “Okay, let’s have a senate like the old Roman Senate. Let’s have our top families form a council. They will rule. We’ll set up a republic.”

A weaker town that can’t support itself as well is much more prone to one wealthy family realizing that they can get goons and take over, declaring themselves the monarch of the area. Or worse, this town cannot self-sustain; it doesn’t have enough. People there can’t get food. They are scared and afraid of being robbed by people who are desperate.

But outside of town, there is a wealthy villa that belongs to a noble family, and they have bodyguards. “Hey, noble family, if I move next to your villa and work for you, will you protect me with your bodyguards?” So towns emptied out, and villages—as in a villa and its environs—developed as a result.

A village was a monarchical structure in this sense. It was the migration of people out of a town into the protection zone of a local lordling. Then those villages grew to different scales, some of them cities, some not. Italy had great agriculture and great agricultural land, so more of Italy’s cities were able to sustain themselves as towns and be republics.

I feel like the big takeaway of your book is that they were trying to resuscitate Roman virtues. What were the virtues that the Roman emperors had which allowed this safety, good government, and so on to work?

I don’t understand the connection between reading Cicero and contemplating the virtues of a great emperor to science and technology. Maybe there isn’t one, but do you think there is one? What exactly is that connection?

As with many processes, the answer is that there are multiple steps, it’s complicated, and some of the steps involve realizing that the earlier steps didn’t work.

Petrarch, who lived through the Black Death and lived in a moment when Italy was wracked by civil war and foreign mercenary troops were raiding and pillaging, saw Italy wracked by bandits. When Petrarch survives the Black Death after losing so many friends, he gets a letter. Two of his friends are alive. He had given up hope that anyone he knew would survive, but two of his younger scholar friends are alive. They’re going to come visit him.

On the way, they were attacked by bandits. One of them was killed, and the other was lost in the mountains and wounded. Petrarch didn’t know that his friend was alive for another year and a half. The bandits are very real in this period.

Petrarch looks around him and says, “This is an age of ash and shadow. What we need is to imitate the arts of the ancients. Let’s try to figure out how the Romans did it.” Specifically, the problem is our leaders. Our leaders are selfish. Our leaders care more about their wealth and their family honor and their power than they do about the people.

This is where Romeo and Juliet is really helpful for us to understand. Lord Montague and Lord Capulet, as their goons are knifing each other in the street, care about defeating each other. Do they care about the good of Italy? Do they care about the good of the city of Verona? No. Their feud is harming the city of Verona, and they don’t care. They demand that Romeo get away with murder because he is their son. That is not service to the state.

Petrarch reads about the ancient Roman Brutus—not the one who killed Caesar, but the ancestor to whom that one was trying to live up. Brutus was one of the first consuls of Rome, and he learned while in office that his sons were plotting to take over the state and make him king. So he executed his own sons for treason against the state.

Can you imagine Lord Montague wanting to execute Romeo for treason against Verona? He would never do that. When you’re living in the plot of Romeo and Juliet and you read about these ancient Roman figures, as described in the lofty biographies of someone like Livy, you read them and say, “Wow, if only our leaders would act like that.”

Well, how were they raised? Can we raise our leaders the same way? Can we make libraries filled with what young Cicero read and what young Brutus read? What did they read? They read Plato, and they read Homer. So we need these things. Can we recreate the educational environment that produced them?

Petrarch suggests this. His students and successors embrace the idea and pour money into traveling across the Alps to look for manuscripts, traveling to Constantinople to purchase manuscripts from the wealthier East, where books are common, and bringing them back to assemble these libraries.

Then they raise tutors like Marsilio Ficino, who can know Greek and Latin, and surround the young princes and princesses of Europe with these values in the hopes that they will act like Brutus and not like Lord Montague.

This is based on an assumption that education is very much like osmosis: if you’re exposed to something, you’ll imitate it. The uptake of this is strong because Italy is also full of upstart rulers who just seized power five minutes ago by having a coup in their state, have no legitimacy and no right to be ruling what they’re ruling, and are resented by their people.

But they can dress up like a Roman emperor. They can have a parade with allegorical figures of the virtues next to them. They can invest in an impressive palace that has a pediment on the front and looks like a Roman building to the eyes of the period, and cover themselves with the trappings of antiquity.

Then people might look at them and say, “This guy is different from what we’ve had. This guy is like the Caesars. The days of the Caesars were pretty good. Maybe we want this guy. Maybe he’s not going to be a tyrant. Maybe he’s going to be a good prince, and he’s going to make a golden age.”

The first dream is idealistic: let’s make better rulers. The adoption is self-serving and propagandistic: “Hey, I’m a tyrant, but I can seem like something better than just a tyrant. If I make myself look like Julius Caesar, then people will like and respect me.”

Or, in the case of Florence with the Medici: “We are merchant scum. We are dirt compared to everybody around us. We’re not even one of the important families of Florence. We’re three ranks down. Even by the standards of merchant scum, we’re extra-scummy merchant scum. But if we can have Latin and Greek and quote Cicero and seem like the ancients, people will take us seriously and respect us and talk to us, even if we don’t have it.”

Let me give an example. Imagine that you are an ambassador from France, and you’re on your way to Rome because a new pope has just been elected. Whenever a new pope is elected, every country in Europe has to send a special ambassador whose job it is to deliver a long-winded oration that says, “I am the ambassador from a very wealthy country and a very powerful prince, and he’s so glad you’re the pope. Congratulations.”

Only you have to do that for an hour. You have to give a gift to the pope, and it has to be very impressive, and you have to be a really important person. You’re the most important person who can leave your country without causing a political crisis. You might be the heir to the throne, for example. Or you might be a more minor ambassador, but you’re at least the son of a count.

You’re on your way to Rome, heading along the length of Italy, and you’re going to go through Florence because it’s on the way. Ugh. There’s nobody there worth talking to because it’s just a pit of scum and villainy. In fact, it’s also full of filth and depravity because, of course, Florence is the sodomy capital of Europe.

“Florentine” is the verb for anal sex in several different European languages. In the laws of France, you can be indicted for sodomy on the grounds that you have ever once in your life even visited Florence. That’s considered evidence enough.

So you’re on your way to this matchlessly filthy dive of scum and villainy. Then you approach the city, and there are these statues. They look like ancient statues, the kind that are so lifelike that it’s as if they’re about to breathe and move. You’ve never seen an intact new statue like that. That isn’t something we know how to do.

You ride through the city a bit, and it’s a large, impressive city. You get to the cathedral, and it has this massive dome, way bigger than anything you’ve ever seen except for old Roman ruins.

You come to the banker’s house, and your servant knocks at the door. The banker greets you humbly at the door and apologizes that his humble palace is not worthy to host Your Excellency, and you’re like, “Yeah, it’s not. You’re correct.”

He invites you in, and the instant you step inside, you’re in a space like nothing you’ve ever seen before, with white light streaming in through this airy, rounded, windowed courtyard that feels cleaner and more outdoors than the outdoors did, because something about the air is cool and fresh.

It’s like the Roman ruins in the backyard of the castle where you grew up.

But we don't have the ability to do that anymore. All that's lost. In the middle of the square is another one of these bronze statues that looks like it's about to come to life, except it's shining and new. It hasn't even turned green yet.

Around the courtyard are busts of all the Roman emperors in order, and above them are portraits of this guy and the members of his family. Off in the corner are some men wearing robes that look like the robes the ancients wear. You say, “Who are those guys?” He says, “Oh, they're Platonists. They're speaking ancient Greek.”

You say, “I thought I didn't understand that language, but ancient Greek is lost. We don't have ancient Greek.” He says, “We have lots of ancient Greek here.” You say, “And also, we don't have the works of Plato. They're also lost.” “Oh, we have lots of Plato here. Look, here's my grandson, Lorenzo. He's just written a poem in ancient Greek about the three parts of the soul. Would you like to hear him recite it?”

Now there's a 10-year-old boy reciting a poem at you in ancient Greek about the three parts of the soul, and you're like, “Where am I? None of this is possible. None of this has existed for a thousand years.” That's the moment that Cosimo de' Medici turns to you and says, “Would you like to make an alliance with Florence?”

And you can say no. You can say, “No. My king is going to come over the Alps with his enormous army, and we're going to descend upon this city, and we're going to sack it, and everyone's going to let us because it has no friends because it doesn't have any nobility, so it can't marry anybody, so it has no meaningful allies.”

“And also, it's in the middle of this Guelph–Ghibelline feud, so all of its neighbors hate it and they're just going to let it burn. We're going to take the enormous piles of gold that are in your basements and go home rich, and all of this will be gone like a dream.”

Or you could say, “Yes, let's make an alliance. Give me a bronzesmith and an architect and a Greek teacher and a Platonist, and we're going to take all of these things, and we're going to do the French court like this. Then when the ambassador from Portugal comes, he's going to feel like an uncultured fool, just like I feel right now.”

The power dynamic just flipped upside down. Suddenly, the condescending nobleman is in awe of the merchant scum. That's what the art and the culture does as a propagandistic tool.

The next stage of it then is, “Okay, we've raised these princes like this, and they have the Latin, and they have the Greek, and they can impress everybody.” Then they fight a bigger, nastier, worse war than any of the earlier big, nasty wars, with more deaths and more betrayals and bigger cannons knocking down cities and burning whole areas.

The wealth is centralized, so the mercenaries are more numerous because people can produce more. The first generations raised by this are supposed to be philosopher princes, and instead we get Cesare and Lucrezia Borgia, both of whom had Latin and Greek and Cicero and Plato when they were kids. Then they grow up, and Cesare sets fire to half the world.

That is the war Machiavelli watched. Machiavelli was raised on all of the Cicero and Livy. He was raised on the Petrarchan project. He has this famous, beautiful letter that he wrote in exile, where he's describing his day to his friend.

Most of the day is wasted, and he mucks around hunting for larks. Then he goes to a pub and gets drunk in the company of uncultured countrymen. Then he goes home, and he gets dressed in the court robes, the court finery that he would wear back when he was an ambassador to popes and kings.

Attired thus, he enters his library to hold commerce with the ancients. He loves this the way Petrarch wanted him to love it. But he observes these wars, and he observes virtuous princes like Guidobaldo da Montefeltro, who does every single thing you're supposed to do virtuously.

He has all the Plato, and he has all the libraries, and he has all the art. And he gets betrayed, and his city is taken away from him, and he loses everything. And he watches terrible people like Cesare Borgia and Julius II make terrible choices and succeed.

He says, “Okay, clearly Petrarch was wrong that just reading Cicero would make successful rulers like the Caesars. But I still feel in my heart a deep power in the classics.” So he says, “What if the libraries are what we need, but we need to use them differently?”

He proposes what we would think of as political science. We observe historical examples. We say, “Okay, here are 5 examples of battles that happened next to rivers. We'll put those examples side by side and see what decisions the commanders made to try to figure out which one worked better.”

We use history as a casebook of examples of what worked and what didn't. We imitate what worked, and we avoid doing what didn't. Instead of feeling that reading about good men will make us good, we read about wise choices, and we imitate those choices.

This is one of the reasons Machiavelli is described by his contemporaries as a historian. He says we need to use history and use the classics differently. He proposes that. He isn't very popular in his own day. It takes a long time for that to catch on.

Many people for decades after him are still trying to use absorption by osmosis. But he's writing that in the early 1500s, so it's been a little over a century since this started. We have to remember how long this process is.

From Petrarch's first call to Machiavelli writing, that is as long as from Yuri Gagarin's space flight back to Napoleon. The childhood of Napoleon to the space race, that's Petrarch to Machiavelli. We think of it as one time period, but a lot changed.

They had a plan. They tried the plan. They brought the plan to its maximum. They raised all the princes in this new way. The wars happened. It clearly failed. Machiavelli then thinks about why it failed.

We're still only halfway through the Renaissance. Shakespeare's grandparents have barely been born. We have a lot more time to go. So what do we need? We need new ways of thinking about it.

We're reading the ancients, and we have bigger libraries. We have the printing press now. We're having libraries in smaller towns. More and more people can read. It's easier and easier to get an education. More people are starting to learn about science.

It also is important that they're inventing microtechnologies of book production like footnotes and glossaries in the margin that explain the hard vocabulary. When Petrarch's successors like Ficino were young, you had to be a masterful Latinist to read these ancients. You had to have an enormous vocabulary.

There are no dictionaries. There are no glosses. There's nothing to help you. Only a tiny slice of expert classicists could actually read this stuff. A hundred years later, there are translations into the vernacular. There are footnotes that tell you the hard vocabulary.

Any med student can read Lucretius' discussions of materialist information. When Poggio found it, there were 2 dozen people in the world who could read it. A hundred years later, 30,000 people can read it in the 30 print editions that are printed before 1600.

When all different kinds of people read it—med students, law students, people in different countries, people in different places—they ask new questions. They wonder whether they can test the hypotheses. They do test the hypotheses. They're the generation that discovers that the heart is a pump.

They're the generation that takes seriously the question, “Maybe there are atoms, and maybe that's how diseases work, and maybe we can develop the germ theory of disease.” That's the 1560s and 1580s, 160 years after Lucretius comes back, because it takes generations of work to build the libraries, to have the libraries, to use the libraries.

So when we get to 1600, which is almost exactly 200 years after this begins, a little bit more, we've had time to say, “Let's build the libraries, have the libraries, use the libraries, or realize we failed in how we use the libraries, and use the libraries differently.”

That's the generation of Francis Bacon and Galileo who say, “Hey, let's use the information differently. Let's use nature as a casebook of examples the way Machiavelli said we should use history. Let's examine, let's doubt, let's rethink, let's do stuff in new ways.”

Just to make sure I understood the chain of causation here: we've got to resuscitate the virtues of the Romans, therefore read what they read. To do that, you need to build the libraries. You build the libraries, you resuscitate all those arts. Then you just need to have people be literate, have people think about information in a new way to analyze it.

And that analysis lends itself not just to the history of leaders, but also to the nature of the world. Whenever I hear a story about how this is why the Scientific Revolution happened, why the Industrial Revolution happened, I'm like, but there are so many stories, and it's just hard to figure out why this one over the other ones.

There's a dozen other stories you could tell. I had a previous guest, Joseph Henrich, who has this theory that the Catholic Church was breaking down these old kinship-based networks that the rest of the world had. It was encouraging guilds, encouraging these kinds of centers where people could get together and discuss ideas. There are probably 20 other stories you could tell. Why this story?

Two different reasons. One, I think it's useful to think about how, for new ideas to flourish and new ways of running the world to happen, you need a fertile environment. In the same way that for forests to grow, you need enough topsoil.

It takes a while to get that topsoil. It takes a while to get enough books. You need to have enough books for a bunch of people to be reading and thinking. You also need to have networks of information moving this stuff back and forth so that they can have discourses of ideas with each other.

You can't publish a scientific journal until there are journals. You need to have developed this ecosystem of information and knowledge.

People talk about it sometimes in terms of increasing literacy rates, as if higher literacy makes there be more books instead of the other way around. In fact, there was a lot more literacy than people imagine in even medieval Italy. Florence had a male literacy rate of 90% as of the 12th century.

Because everybody was in the merchant world, you had to be able to send letters. You had to be able to read account books. You had to be able to calculate your tab at a restaurant. But of those people, how many had read a book? Very few. They had read letters, tallies, and indexes. They had made notes.

The difference between being literate and being book-literate is different. In the same way, some people watch television but don't watch very many films, while other people watch lots of films. You can be literate and have never read a book because there might be almost no books in the entire city in which you grew up if it's 1200 or 1500. But if it's 1600, there are definitely books in any medium-sized town.

So literacy transforms into access to scientific, intellectual, legal, and all sorts of different worlds of ideas. The other person you quoted, who's talking about transformations in networks of power from being less family- and clan-centered to being more guild-centered—the guilds are major generators of ideas as well. The guilds can own libraries by 1600. If you went to a guild hall, it would have a bunch of books about its own trade. That would not have been true in 1100.

Those changes are all real, they're all intermixing, and they're all parallel to each other. You need all of these things together. One of the focuses I have is that sometimes there are more steps to something than you think. We tell this story of the Renaissance, of how they rediscovered these ancient texts, and then we got science. That's true, but it is an oversimplification and too wide a zoom.

If I said that in the French Revolution, Napoleon rose to power and spread nationalized warfare across Europe, and then we landed on the moon, I've skipped some steps. We know that about modernity, but we don't remember that about earlier periods.

Obviously, all the stories are somewhat true, but to the extent that this is a part of the story, you're building up libraries of classics and setting up a network of information exchange that leads to the Scientific Revolution. The reason this feels salient right now is that a lot of people have this idea that they're going to make AI go well by doing X thing.

Maybe some of those things work, but it's at the same time frustrating, funny, and interesting that historically nobody has a good track record of being able to say, “I will do this thing so that this huge, unanticipated change in history will go my way, or according to my values.”

Right. I think “go my way,” as opposed to “go well,” is a really important distinction. Petrarch wanted a world with these values. He thought, for example, that this would be a triumph for Christianity and what we would call Catholicism, though there's only one Christianity from his point of view at the time, except for the East, which is different.

He was sure that when we found the ancients, fundamentally all of their philosophy would agree with Christianity. The ancients were wise, therefore they would be correct, and Plato would 90% agree with Christianity. It just needs a little shaker of the Trinity on top to be Christianity.

When he says, “Go find these ancients,” he is in a world that doesn't have the ancients yet. He's just guessing what's going to be in these books. But he says, “If we find them, they will uphold good values,” and everyone believes him.

Then they go find them, and they squabble with each other. There are Hedonists and Epicureans and Stoics and all sorts of chaotic things, much more plural than he anticipated. It makes a world that in turn has giant wars, which he would not like, and a crisis, and Machiavelli's critique of the ancients, and then the new science and the new philosophy, and eventually Galileo—none of which resembles what Petrarch imagined if he had specifically described the future he was trying to make.

But then we get to the propagators of Bacon's scientific method, meaning Voltaire and Montesquieu, who are also big campaigners for inoculation against smallpox. The first major disease eradications start to begin under that immediate influence.

Science gets us to the germ theory of disease, gets us to modern hygiene, which gets us to vaccines, which gets us to penicillin and the treatment for the Black Death. Petrarch thought he would make a world which shared his values. Instead, he made a world that doesn't share his values but is capable of curing a disease he never imagined would be curable.

If you showed him this future, it would be scary. It would be weird to him because it does not embrace his values. Our values are different. He would be horrified by democracy. He believed that only a tiny elite had the capacity to rule. If we had a time-traveling Petrarch, he would really wrestle for a long time to wrap his head around democracy as a functional system. He really thought in oligarchic terms.

But he would see the wonders we've created, especially the fact that we can treat the Black Death, and he would weep for joy seeing that. He did not create a world that went as he wanted, but he created a world that went well. We have many examples of that.

Trains and bicycles come in, and we get feminism because it's easier for people, especially women, to move freely and independently. They can organize. They can mobilize. We get suffragettes. Did the inventor of the train intend for there to be women's liberation? No. Did it go the way he imagined? No. Did it go well? Yes.

1. How Florence's weird republic worked

It's important here to zoom in a little bit on Florence's own government system and how and why it's weird, in order to understand what rank Machiavelli actually holds in it.

All of these republics, except Florence, are modeled on ancient Rome. The ancient Roman model was an oligarchic republic in which, within the city, there were certain noble families—usually founding families who made the city in the first place—who were the senatorial families. Hereditarily, when they came of age, the men of the family were automatically in the senate. From among them were elected the consuls, high senators, or the head of state if there was one.

You had a small slice of the population that were fully enfranchised members of the republic who ruled over the commoner majority. That is how Venice works. That is how Genoa works. That is how Bologna and Siena, for the most part, work. That's how the Swiss Republic works. That's how all of these republics work.

Florence was like that for quite a while, but when republics fell, they usually fell to noble families who were the foremost, strongest military class. If you're a military leader in this period, you have to have noble blood. No soldier is going to follow a commander who doesn't have noble blood. That would be weird.

Those threats to the independence of the republic almost always came from the nobility. After one particular near miss, in which the city was nearly taken over, they decided to get rid of the nobility of Florence. They massacred most of them, cut their heads off, put them on pikes, burned their houses down, raked salt into the earth, and had a party on their graves—the way you do in the period when you're getting rid of a class of people.

There were a few noble families that they really liked who had not been part of the negative stuff. They allowed them to officially renounce their nobility. They renounced their nobility, changed their names, and declared themselves commoners. They set up a commoner republic.

What that meant was that the senate consisted of members of merchant guilds. A member of a merchant guild here means the owners of workshops. It’s not the guy who sits at the loom weaving, but the guy who owns the warehouse full of looms where the workers are working. The head of the sculpture works, the head of the architectural firm—not the bricklayers who are actually laying the bricks.

“Bourgeoisie” is an anachronistic word, but we're talking about the owners of the means of production who are themselves commoners. They are very wealthy, but from the point of view of the diplomatic corps of any other society, all of the ruling people and all of their ambassadors are noble-blooded. If you're an ambassador, you're automatically noble-blooded. Nobody's going to take an ambassador seriously who isn't.

From the perspective of every other polity in the world, the rulers of Florence are the rank of their valet. There is no nobility left in the city. In fact, Florence can't run its own armies or head its own police, because you're not going to surrender if you're told to surrender in the name of some guy who doesn't have a coat of arms. That would be weird.

So they actually have to hire a nobleman to come to the city and be their chief of police, to arrest people in the name of the Holy Roman Emperor. One at a time, they'll invite a skilled military commander, a nobleman who will come to the city. He'll be podestà. He'll live in the palace, which is also the prison. He'll arrest people. He'll enforce the law.

They will pay him handsomely at the end of the year, escort him to the gates, and then banish him from the city for life, on pain of death, so that he cannot return and make use of the power that he had in the city to try to take over.

They're very wary of any nobleman. They've set up a really weird republic—weird from the perspective of everyone around them—in which a bunch of merchants are trying to share power by being lotteried into the senate.

You put names in a bag. You examine all of the merchant members of guilds. You choose which ones are fit to serve, meaning not ill and dying, not insane, and not so deeply in debt that they could be manipulated by the people whom they owe money to. Their names go in a bag. You choose 9 guys at random. They rule the city.

They are put in a palace where they rule the city from that tower. They’re actually locked in the tower for the duration of their time in office because if they left the tower, they could be bribed or kidnapped. They rule the city for 2 or 3 months. At the end, they are thanked for their service and escorted out, and then a different 9 guys share power for the next 3 months. It’s a power-sharing system designed to be tyrant-proof because you need the consensus of 9 randomly selected guys to decide to do anything.

Oh, it’s not even a majority vote? It’s consensus? Previously, you were describing “kill the nobles, salt the earth.” I’m almost thinking: early communists. But then you say it’s the heads of the merchant guilds who are in charge. I want to understand why merchants and entrepreneurs have notable status in Florence. What is it about the culture that makes it so? Also, the Medici, the most powerful people, their job is usury.

It’s important to remember they were nobody when this was set up. They were a minor, important family. But the culture is getting started in which somebody like that could be respected. How does that happen? An important part of it is that when you have a merchant capital, everybody works for somebody who works for somebody who works for the boss. If you are a major merchant in Florence, you’re importing and exporting wool to and from all across Europe. You have employees all across Europe. You’re buying mass quantities of wool from England, importing it to Florence to use olive oil that you’ve bought from Naples to process into high-quality wool, which you’re then exporting to Germany and France.

You are a very interconnected businessman. You have a lot of contacts and a lot of clout, and the employees who work for you look to you for their safety net as well as their political representation. We’re very accustomed in the modern period to thinking of the government as being our big safety net. If we wonder who is going to fund the hospitals or whose job it is to take care of orphans, we think of the government, or maybe the church.

But in this period, if you’re killed and you leave orphans behind, it is your employer whose duty it is to take care of them. If you are injured and can no longer work, it is your employer who will support you for the rest of your life while you are disabled and find you work that you can do with that disability. A huge portion of the safety net is your employer. Are you in trouble with the law? Your employer will supply your defense attorney. Your employer will supply the persuasive note to the judge that they would very much appreciate if their person got off.

This is the system known as the patronage system, and it existed in ancient Rome. It exists and saturates the medieval and Renaissance worlds, in which everyone is in a very interconnected hierarchy. So if you’re a brewer and your son gets in a barroom brawl, punches somebody out, and the person’s nose breaks and they die in the brawl, and your son is suddenly in trouble, you say, “Oh no, I don’t want my son to be executed.” You turn to your landlord. Your landlord turns to his landlord. They turn to 1 of these major families.

These major families are massive landowners that own dozens of apartments within the city. Hundreds or thousands of people work for them. So it makes sense to everyone to be represented that way, like having a council of the CEOs of all of the organizations that employees work for, when your corporation also supplies your social safety net and you see your representation there. It’s also a world that’s used to thinking in terms of hierarchy and very unused to thinking about real democracy. It really doesn’t have any confidence in what we would recognize as democracy.

We talk about these republics, and we’re very excited by the fact that they give more power to the people than a monarchy does, but they’re still incredibly narrow, oligarchic republics. When we read Machiavelli, he talks a lot about the popolo, which we translate as “the people.” He talks about how important it is that the popolo are respected and have a voice, that the popolo are armed, and that the government shows respect for the people by allowing them to be armed.

We read this and we’re like, “This feels really familiar. This feels like documents from the founding of the United States, where we’re respecting, arming, and trusting the people.” The popolo meant the top 4% economically of the population, the members of the merchant guilds. That’s the popolo. He’s talking about a narrow-slice oligarchy being heard, a narrow-slice oligarchy being respected.

2. How the Medicis took over Florence

We didn’t realize that in the 19th century, when we were excitedly translating “The Prince” and reading it as quasi-democratic. We’ve now read more documents of the period and realize how people used these words. Florence in this period goes through 5 different forms of government. It’s this republic of 9 dudes in a tower, as you were saying, before 1434, and then—

There’s a gradual takeover, what we could call regulatory capture.

But an interesting detail about Florence, even as the Medici take over, is that the Medici know the people of Florence are very deeply invested in this republic and very deeply invested in its institutions. Therefore, they have to respect those institutions and proclaim respect for those institutions. So they’re going to sustain people in the named offices that used to be there. They’re going to continue to let the guilds be important and have important offices.

There was a mandatory outfit that people who worked in the republic had to wear. The garment over there in the corner is a lucco fiorentino. This was the garment you were mandated by law to wear if you held office in the Florentine Republic. To us, we look at it and say, “It’s a long red robe. It looks very Renaissance.” To them, it looked like a toga because of the way it was draped.

They thought of this as a toga. They’re cosplaying the Roman Republic. Wearing a Florentine toga while in office was something that you did to represent your fealty to Cicero and republican values. The dukes made their men continue to wear these. In fact, the 1st Duke, Cosimo I, would wear one to costume balls, as if in his heart he longed not to dress like a duke, but to dress in a toga like a republican.

It’s doubly ironic because when the Roman Republic turns to the Roman Empire, they still have the Senate. They still have all these old institutions, even though it’s no longer a republic. The Roman Senate keeps meeting until 1200 AD. It’s sort of doubly ironic that they’re doing the same thing, but in the 1500s. And it means that more rights are granted to the people of Florence than to other cities that fell to monarchies at similar points.

The monarchs of Florence know they have to be careful, they have to respect rights to a certain amount, and they can’t run roughshod over them. There’s a really cool building that I love in Florence. If you’ve been there, there’s the famous bridge, the Ponte Vecchio, which has little jeweler shops all along it. When you get to the end of it, there’s this funny overhead corridor, the Vasari Corridor, which was built by the dukes of Florence to connect the old city palace, where the Senate used to meet—where they had to have their seat of power—to their new palace across the river, which was much bigger, where they could have grand balls and things that dukes need to have.

Because they’re so terrified of being assassinated by their own people, they built this overhead walkway that goes from one end of the city to the other so that they could walk in safety without being assassinated. This is a sign of a weak duke. But also, when he was building it, it was going across the roofs and sometimes blasting off the second stories of different people’s houses. Most people, when His Grace the Duke says, “I’m going to blast the top story off your house,” would say, “Yes, Your Grace, please continue.”

There are literally severed heads of people who resisted still rotting on spikes in front of the Palazzo Vecchio. But they get to this 1 point where there’s a very old tower, a 500-year-old tower. This belongs to the Mannelli family, who are descended from peers of Julius Caesar and can trace their genealogy all the way back to an old Roman gens.

When the duke says, “We want to knock the top off your tower,” they say, “No, this is our tower. This tower has been ours since before the Medici existed as a named family. You may not knock the top off.” And the duke does not knock the top off. The corridor goes around in this awkward square around that tower because he knows that if he violates something as traditional and core to the civilization as the property rights of somebody who has owned something for a long time, there will be rebellion, civil war, dissent, and resistance.

These are monarchs who know that they are weak and are therefore careful, and therefore more rights, like property rights, exist. Meanwhile, across the river in Ferrara, Duke Alfonso I d’Este of Ferrara used to wander around Ferrara buck naked with a sword in 1 hand and his dick in the other, to show off that nobody would ever possibly try to harm a Duke d’Este.

He and his siblings used to do things like this: if they liked a musician, they would kidnap them and lock them in a tower so that nobody else could hear them, or if they wanted each other’s musician, they would send goons to kidnap each other’s musicians. They also used to recreationally murder each other’s servants when the siblings were tiffing with each other. That is what you do when you don’t fear your people and when you feel confident in your power. They are much closer to tyrants than the Medici are ever able to be, even after the republic falls.

That’s what’s so neat. Because the resistance failed, if we’re looking at it in black and white, the republic fell. There wasn’t a republic anymore. There was a duke. He took over, and the old system was gone. But because the republic fought so hard and because the people really believed in it, the people had a lot more rights, and the tyrant was a lot less tyrannical because there had been that fight.

It’s a great example of how, even when resistance loses, resistance wins. I think there’s an interesting parallel to today, not to be too on the nose, but sometimes people debate the odds that America becomes a Putinist kind of country within a couple of decades. I think the odds are actually quite low, just because even though constitutionally, or at least in precedent, the president is very powerful, the republican expectation is so strong.

The amount of resistance faced, even when you successfully do something, demotivates the next escalation. The only thing that makes resistance weak in the US is when people feel as if partial victory is failure. Remembering moments like how Florence’s resistance all the way to the end meant that there was more liberty for the next several centuries, even under the tyrant, is what we need to remind ourselves: partial victory is an important thing.

Even if the worst were to happen and there were to be tyranny, that tyranny would be so much weaker because there was a lot of resistance, and traditions of resistance and structures would develop that would continue to exist. I think you should discuss the fact that the Medici are the bankers for the papacy. What does that mean? Why is that necessary? How are they able to make money off of that from the interest on the float?

When Cosimo de’ Medici swings the contract as banker for the pope, it’s important to remember that when you can’t wire-transfer money in the pre-modern world, collecting taxes is a very difficult and complicated system. It is generally done by the centralizing power that has the right to tax delegating somebody local. If you’re in a town, there’ll be a local tax collector. It’s his job to go around to everybody and collect taxes, send a portion of those taxes home to the central power, and keep a remainder to pay himself.

The central power will say, “We expect X amount of taxes from this area.” When you hear about wicked tax collectors, it’s because if you are told, “We want 10,000 florins’ worth of tax from this town,” but you extract 15,000, you can keep the other 5,000. The 10,000 is what you need to send to the central power, so the more you extract, the more you get paid.

This delegate system, in which there’s a local tax collector and even a more local tax collector below him who might collect tax from a particular village, means that you depend a lot upon the person whose job it is to collect your taxes. When Cosimo is papal banker, he is the person collecting and channeling the money from every church in Christendom. When everybody puts a coin into a collection box, or pilgrims come and put money in, all of the wealth that’s supposed to flow back to the papacy is actually flowing to Cosimo.

Cosimo is passing it on to the papacy after taking a cut. That is a lot of money moving quickly. There is also a lot of ability to make contracts and contacts. We all know how important networking is.

He rises in prominence from a banker to somebody who has enough money to effectively take over his state via manipulating the guys-out-of-a-bag system. To discuss that again briefly, if you have a system where you lottery people, sortition is the technical term for it. This is a very old form of government. Ancient Athens used it. It actually works really well.

But like any institution, it is corruptible. In the same way that you can corrupt voting by bribing people or manipulating the machines or manipulating voters, you can also corrupt sortition by bribing the people who pull names out of the bag.

Or you can use the simpler mechanism, which Cosimo uses first. If you’re a giant bigwig in the city and you employ a third of the people in the city and they’re on your payroll, and 9 guys at random are chosen out of a bag, 3 of them are going to be your guys, just statistically.

If you tell all your guys, “I want this policy, this policy, and this policy, and if you have questions, send for me and I’ll tell you what to do,” when the plurality on a random council all have a plan and it’s your plan, you effectively control the city. In that way, the Medici effectively controlled this lotteried system, because they guaranteed that the plurality, in a situation that doesn’t have a majority, will always be them.

But of course, there’s a chance to that. In 1430 and 1432, Cosimo has bad luck, and the lottery draws a lot of people who dislike him and doesn’t draw any of his guys. They immediately declare him a traitor to the state, arrest him, and lock him in a tower.

And he bribes his way out. He offers the equivalent of about $300,000 to the guard outside the cell and $700,000 to the captain of the guard to smuggle him out of the tower. He wrote in a letter later that they were the 2 most foolish men he’d ever met because he was Cosimo de’ Medici. He would happily have paid them tens of millions of dollars to let him out of there, but they weren’t ambitious enough to think to ask for more than a few hundred thousand.

So he escapes, and then the next election they happened to elect entirely people who just loved Cosimo. They invited him back to the city in triumph, declared him father of the fatherland, and arrested and persecuted all of his enemies, who turned out to be guilty of tax evasion and all sorts of other things.

That was the moment that his grip tightened. He says, “I’m going to stop simply controlling a plurality, and I’m going to start bribing the people who actually run the elections.” His famous quote about this is, “It is dangerous to be rich and not powerful.”

You need the power to defend yourself in a situation like King of the Mountain, where when you’re on top, everyone will try to knock you down. This is the system into which Machiavelli is born. His family has worked for the Medici family for generations. He grows up expecting to work for the Medici family.

But the problem with heredity is that sometimes you get a weak link. And in the moment that Machiavelli is in his early 20s, he is coming of age, about to work in government for the first time, a government in which he is not, in fact, even fully enfranchised. That’s one of the fascinating things about the degree of his patriotism.

You weren’t allowed to serve in government office fully—the lotteried offices—if your family was deep in debt. His grandfather had a lot of unpaid tax debt. So he worked his whole life for a government of which he was not even quite a full citizen.

That shows a deep love of country, but it also shows that even people who could not be in office deeply loved and cared about this republic and the important liberty they felt they had being ruled by the 5% instead of being ruled by 1 dictator. To us, that isn’t a very big difference. They’re still both not democracy.

We would say they’re both not liberty in the sense that we want liberty. But it’s an inch more liberty than monarchy. Even that small amount of liberty, people loved it. People were willing to fight for it. People were willing to go to the streets, wave their banners, and say “libertas” for the republic.

Because they were invested in it, Machiavelli observes, they sustained it. But eventually, 1 particular Medici—I’m not saying names because they all have the same names over and over, and it’s really confusing—comes to power quite young and weak. He’s basically 20 when he’s suddenly in charge of a very precarious republic.

Right then, the French are invading Italy, and he’s scared. He botches the diplomacy with France and falls into disrepute, and the city takes the opportunity to kick him out. The subsequent regimes, which are an independent republic again, are the ones for which Machiavelli works.

He was part of the regime that ruled while they were in exile. When they returned, they viewed him as an enemy. He didn’t actively organize to resist them, but his name was found on a list of potential people that an anti-Medicean resistance movement had intended to recruit.

He is arrested, tortured, exiled, and in exile writes The Prince. He dedicates it to the very family that exiled him because they now control Florence, and he will only work for Florence. He doesn’t want his manual of the great secrets of statecraft to be in the hands of anybody but his homeland, so that it will defend his homeland.

When Florence exiles you, they tell you, “Go to this place and wait, and if you’re good, we’ll invite you back.” Florence has been doing this for ages because Florence actually used this as the core of its diplomatic corps. When you have no nobility, you can’t have ambassadors in the full-on noble ambassador sense.

There’s nobody in the city of sufficient rank to go talk to the kings, to play chess with the sultan, and do all the things you have to do to be a proper ambassador. What Florence did instead is exile people and say, “Okay, we’re exiling you. You go to Bruges. Be our contact in Bruges. You go to London. Be our contact in London. Be good. Send us letters informing us what’s going on.”

“When we have diplomatic needs to talk to the king, we’re going to send letters to you, and you’re going to forward them. If you’re good, you get to come back.” So being in exile is sort of being on probation, but also being entrusted with state matters.

That’s not quite what they did with Machiavelli. With Machiavelli, they banished him to a hamlet in the middle of the Tuscan countryside near nothing important and said, “Go sit in the country and rot, and if you’re good, we’ll invite you back.”

What everyone expects is that Machiavelli will break that promise and leave. Because he’s a well-known statesman, a scholar, a playwright, and a historian, there are dozens of cardinals in Rome and other cities that would love to employ him.

Kings of England love employing Florentines to work for them as secretaries. Kings of Naples love employing Florentines to work for them as secretaries. He might go get a job tutoring the daughters of the Duke of Milan, the way Francesco Filelfo did when he was kicked out of Florence for opposing the Medici.

There are lots of places it’s expected an exiled Florentine intellectual will go where he will have the ear of power and be able to exert influence.

He will be a mover and shaker at the court of Milan, Naples, or England. Instead, when they say to Machiavelli, “Sit in the country and rot, this is a test,” he passes the test and sits in the country faithfully and rots. If he had wanted to go be an intellectual power broker, the correct move would be to run off to Rome and say, “I will give up the chance to go home the way Dante did, but I will be a Florentine in exile, and I will write important things.”

“I will live at the house of wealthy men who will support me and give me the ear of power, and I will exert my influence in that way.” He does not do that. He stays in the country and he rots, and he continues writing letters home saying, “I will serve you or nothing. Bring me home to serve my country.” That is a weird thing to do, and not normal for the many other Florentine intellectuals who experienced similar banishments in the same period.

How do we know that he wasn’t just trying to get back into power? The answer is, you read his personal letters. You read the way he talks about love of his country, and you read the way he talks to his friends. You read the letters he wrote when he discusses writing The Prince, and you read the comments he exchanges with the other friends that he shared it with.

His other works—his comic play, which was a big hit, and his history of Florence, which was well known at the time—he published and circulated. The Prince he kept in very close private circles, circulating it only with trusted, intimate friends, and then the copy that he sends in to Florence. Yes, it’s a job application: “Please bring me back. I will work for you. I will be loyal.”

“I support my city more than any particular iteration of my city. I support my country more than any particular regime or group that might be in power. Whatever is in power in my city, I will be faithful to it.” You see him expressing that in lots of different ways. When in The Prince he says you can and should do all of these ruthless things to keep power, we have to remember that the end justifies the means when the end is the survival of your country.

It’s not that the end, in general, justifies the means. Machiavelli feels very strongly that regime changes bring civil violence, and civil violence sheds blood. He has seen the streets of his city run with blood before. He thinks that even life under a tyrant is better than life in a civil war, which is usually not life at all, given the massacre of the people and external conquest that are likely as a result of another regime change.

So he says, “Don’t push for regime change. Even if the regime is tyrannical, more people will survive by sticking with the tyrant than by changing the regime.”

3. Why it was so hard for Gutenberg to make any money off the printing press

I want to talk about the printing press. One thing I didn’t realize before reading your book is that not only does Gutenberg go bankrupt after making the most significant invention of a millennium, but his apprentices also go bankrupt. This is at a time when people like Cosimo are willing to pay on the order of hundreds of thousands of dollars per book. So with the guy who invents a way to make this way cheaper, how is this possible?

The problem is that printed books are a mass-produced commodity in a world that does not have distribution networks for mass-produced commodities. Mass production is incredibly rare in this period. Coins are mass-produced, but that’s really about it. Almost everything is artisanally produced.

When you have a mass-produced product, you need a distribution mechanism before you can sell it. The great example is that, technically, e-books existed the first time anyone typed a book on a computer. Certainly, in the 1970s there was such a thing as an e-book. But there was no market for e-books until the Kindle came out and made a commodity way to buy and sell e-books. Then the e-book industry came into existence.

So the e-book as a commodity is several decades younger than the e-book technically existing. In the same way, you’re Gutenberg. You have figured out how to produce 300 copies of a book for the cost of 1 copy of a book. You do so. You print your Bible. You have 300 Bibles.

You sell 7 of them to the 7 people in your small, landlocked German town who are legally allowed to read the Bible in a period in which only priests are allowed to read the Bible. Congratulations, Mr. Gutenberg: you have 293 Bibles, and you can’t sell them, and you go bankrupt.

There has to be a distribution mechanism for books to find their market because there are certainly 300 people in Europe that want this, but there are not 300 people in one location where it’s being produced. So Gutenberg goes bankrupt. The bank seizes his press. They try to go into the business. The bank goes bankrupt.

There is so much overhead. You spend hundreds of thousands of dollars on the production cost of the books, and then you get nothing back. Gutenberg’s apprentices build presses. They go bankrupt. They flee their debts, flee the country, leave Germany, and go to Venice.

Venice is the airport hub of the Mediterranean. Venice is where you change boats. If you’re sailing from A to B, you go to Venice, change boats, and get to the next place. The hub system has always worked well.

So if you’re printing in Venice, you print 300 Bibles, and you give 10 Bibles to each of 30 ship captains going to 30 different cities. They can sell them. The first economically sustainable circulation of print is enabled by the hub system.

Then book fairs come into existence, in which printers will spend all year printing a book. They go with 1,000 copies of their book to a book fair where there are 1,000 other printers. They all trade, and then they go home to their town with 5 copies each of 200 books instead of 1,000 copies of 1 book, and then they sell them in bookshops.

Things like the Frankfurt Book Fair, which still exists today, developed as the distribution mechanism. There’s a slow growth and a slow saturation.

That’s really cool, because one of the things people think is unique about our present information revolution is that we’re living in this sequence of successive information revolutions. We had the computer; the computer was exciting. Then we had the personal computer, then we had the internet, the cell phone, social media, and now we have different social media networks coming in successively, causing crises one after the other.

And then we have LLMs and other applications of machine learning and generative AI. It’s easy to think of each of these as different tech revolutions, as if we’ve just had 10 tech revolutions in a row. But really, they are all deeper penetration of 1 tech revolution: the development of the computer.

These are all applications of computers. In the same way, the printing press comes in in 1450, and it isn’t done shaping the world instantly. It takes 40 years to even be economically sustainable. It’s not until the 1490s that printers are making money.

Then, in the 1510s, it’s time for pamphlets and pamphlet distribution. Now there’s news, and news is suddenly done by print, and that’s a revolution on the same scale as the difference between computers and cell phones. We get the Reformation, which is enabled by pamphlets in exactly the same way that the Arab Spring is enabled by cell phones.

Then we get the newspaper, another new application of the same technology that follows, like social media. It’s 1 information revolution having multiple successive revolutionary applications as it disseminates and eventually saturates. It moves on a timescale quite similar to the timescale in which the digital one is happening as well, so that print keeps hitting Europe with successive revolutions for 150 years.

And every couple of decades, or every decade, there’ll be a new bang. Suddenly it’s possible to get a printed pamphlet from Wittenberg to London in 17 days. Oh my God, we can coordinate our resistance movement against the Catholics. Boom. The Reformation happens.

That wasn’t possible even a decade earlier, when it took months to get a pamphlet from one end of Europe to the other. So it’s best to think of these very much in parallel—the print revolution and the digital revolution—as 1 big technological change in information that then has successive applications as that 1 technology finds new forms, disseminates more deeply, and keeps having consequences over decades.

It’s not multiple separate revolutions. It’s 1 ongoing information revolution.

Maybe other eras also have this, and I just haven’t read the books about them, but from your book, I thought, “Oh, history just seems to be happening really fast, and seems to have sped up, especially religious and political history.”

Obviously, the things happening in Italy, but even aside from that, you have Martin Luther and the Reformation, and then just 20 years later England splits off from the Catholic Church, which is unprecedented in 2 millennia. Then it has a bunch of tumults that flop, flop, flop, so that every decade feels different.

Here you are in 1506, being nostalgic for how the world was completely different in 1490. And you’re like, “That’s pretty fast.” Here we are in 2026, often feeling nostalgic for how things were in the year 2000. Is it fair to trace that back to the printing press or its offshoots, or is it just embedded?

It’s more that history has always moved fast. But when we teach it in high school, we’re trying to move over large chunks of time quickly, and so we pretend that it moved slowly. We have this lie that there were long periods of stagnation.

But you can zoom in anywhere, and you’re going to find every decade feels different, and people in the 1320s are nostalgic for people in the 1300s. It’s always felt like history was moving very quickly, and things rose and things fell.

It’s the lies we tell ourselves in history books written in the 19th century that are trying to group all of these things together and make modernity special that confuse us about this. I’m working on a paper right now about the video game Civ. Civ is the number one teacher of history in the world.

It has shipped 70 million copies, and 65 percent of people on Earth who have technology play video games. Civ is the number-one teacher of history, bar none, since 1991. What does Civ tell you? Civ tells you that in antiquity, a turn is 50 years, and then in the Middle Ages, a turn is 25 years.

Once you get into the Industrial Revolution, a turn is 10 years, and then 5 years, and in modernity, a turn is just 1 year because in 1 year, as much happens now as happened in 50 years in antiquity. That lie is also what our textbooks tell us. But it doesn't matter where we zoom in. Any time I go to a talk where any historian is zooming in on any decade in any time and place, it always feels like it's moving as fast as our present is moving.

I guess the difference is that technologically, we know that they weren't moving as fast.

Technologically, they were moving fast. We just don't care about those technologies anymore.

That's interesting.

They were constantly inventing all sorts of things. We just take them for granted. The invention of chairs with backs, the invention of scissors, and the invention of improved metallurgy so that steel could do things steel couldn't do before—there was always technological change happening.

I'm in the middle of reading an amazing book about how, when you look at the paintings of Raphael and the few paintings we have by Michelangelo, the colors look like they're really glowing, like gemstones. How did that happen? When you compare them to paintings from just 100 years earlier, somehow the colors are flatter.

I'm not talking about the anatomy being more realistic. That's separate, but the colors are flatter. The answer is that there was a sequence of revolutionary adaptations in how to process oil and how to process colors and mix them together. Then those were used to create fake gemstones, and there was a major industrial leap forward in the fake gemstone industry.

Then people who were making picture frames realized they could use the same techniques from the fake gemstones to make fake gold by painting yellow over the surface of tinfoil. Those techniques were then used by artists who were like, “Wait, I want to make things that look like they glow like fake gemstones.” There were 11 major technical revolutions over the course of 120 years that led to those colors changing.

Obviously, progress has been happening in individual fields over time. But in this macroscopic view—and this is a big part of your book—there's a reason that people living in the 14th century would say, “Look, the best time to be alive was when the Romans were around, and since then it's just been the Dark Ages.”

If they stood in relation to the Roman Empire as we stand to them, we would obviously notice that the world has seen so much progress since then. It's hard to figure out when we are lying and when we are right when we say the pace picked up.

One thing that makes the pace pick up in modern times is simply that the population grew and grew and grew and is now much, much larger. The majority of people who ever lived in the entire history since humans have been humans, and not hominids, have lived in the last 200 years because the population became massive.

How did the population become massive? Our agriculture and our hygiene enabled it. How did our agriculture and our hygiene improve? Half of that is continuing on the artisanal level to invent new things in the same way that the artists invented better colors. Agricultural workers invented better technologies, and agriculture was constantly improving.

You're correct that with the arrival of the systematic scientific method just after 1600, there is a deliberate societal desire to create intentional anthropogenic progress. I'll zoom in on the arguments made in 1600, then I'll zoom out and unpack them.

In 1600, the idea is that history up until now has been unsystematic. People have discovered things at random, but we can create a method in which we observe the world and use inductive reasoning to figure things out from those observations, to create systematic descriptions of the secret motions that underlie nature, and from that work out technologies that are good and useful for humankind.

If, as we make our observations of nature, we publish them and share them with each other, we can create a community of scientists that will share all of these discoveries with each other and with the world and therefore benefit it. This is where, when I'm doing this in the classroom, I deliberately provoke and shock my students with the fun claim that Leonardo da Vinci was not a scientist.

What I mean by that is that to be a scientist is to publish your results and share them with a community of other scientists so that they can test them, so that the whole of human civilization progresses a little bit. When my friends who are chemists or my friends who are particle physicists discover something, the next goal is to share that discovery with everyone so everyone's knowledge advances.

What does Leonardo do? He writes everything he discovers down in coded mirror writing so that nobody but him can possibly use it. He refuses to share even with his students and assistants the secrets of what he's doing because Leonardo does not want to contribute to human progress.

Leonardo wants to make unique masterpieces so that hundreds of years later, people will see them and marvel and say, “How did he do it? No one else has ever been able to replicate that method.” He wanted to be marveled at by the future exactly the way he and his peers marveled at the works of the ancients.

They look at something like the Colosseum or the Pantheon in Rome, with its enormous dome, and they say, “How did they do it? If only we could work that out, we could make one and then make sure no one else could.” Brunelleschi, who built Florence's famous, beautiful dome, deliberately burned all of his notes and schematics so that nobody else would be able to replicate his work.

That is an inventor and an engineer, but in the sense of a community of scientists, this is not a servant of human progress. This is actually a saboteur of human progress, if anything, who deliberately makes progress and then tries to cut it off at that point so that no one else can be his peer.

That is what you did as a learned inventor in the 1400s and in the 1500s. But as you get to 1600, the suggestion is different, and here I'm going to use Francis Bacon's gorgeous simile of the 3 insects.

There are 3 types of knowledge wielders, says Bacon. First, there is the ant, who is the encyclopedist, who gathers information from all around the world. He learns everything he can, and he piles it up into a great big pile.

He makes an anthill, and he sits on top. If he has the biggest anthill, the biggest pile of knowledge, then he's proud of having made it. But all he does is assemble it and possess it. It's a beautiful library, but nothing comes from it.

The second type is the system weaver, the spider who spins elaborate webs of beautiful, intricate, logical theory. You admire them, and you can get entranced and ensnared in them easily because they're so beautiful. They're almost hypnotic.

But there's nothing real in them. They're all just spun out of the body of the spider himself, the theorist theorizing from his own mind. The 3rd kind, says Bacon, is the honeybee, who, gathering from among the fruits of nature, processes what he gathers through the organ of his own being to produce something which is sweet and useful for humankind.

That is the scientist who gathers from nature to produce something sweet and useful for humankind. With this rhetorical call, and with Francis Bacon's portrait on the title page, the English Academy of Sciences is founded and starts publishing.

The standard switches over from “You are not a great achiever because you built the dome” to “You are a great achiever because you worked out how it can be done, and you shared that sweet and useful thing with all of humankind.”

Bacon says if we do this, if we make academies of sciences, we can make sure that every human generation lives in a better condition than the past. We'll have better agriculture and fewer famines. We will have refrigeration. We'll have chicken in winter. We will have all of these things that we aspire to.

If we collaborate, each generation's experience will be better than the last. He says that to be a scientist is the ultimate act of charity because there is no greater act of charity than to give a gift to every human who will ever live after you.

That is the rhetoric of what you would feel was happening if you're alive in the 1620s and 1630s. Galileo is publishing his observations, and Descartes is publishing his systems. They've just discovered that the heart is a pump and that they were totally wrong about the 4 humors theory.

The blood circulates, and they're trying to figure out what it does. They have magnification, and they can see worlds of complex patterns on the wing of a flea. It sounds like the whole world is suddenly coming into view, and we're at the beginning of progress.

If we zoom out, we would say there'd been progress the whole time. People had always been inventing things. Agriculture in France was better in 1300 than it was in 1000.

Plows got better, seed got better, cabbages were bred to be bigger. People worked out better pots. There were always artisanal inventors. In fact, that's a lot of what Bacon is observing.

He worked in the patent office as a young man, and he would see a carpenter come in to patent: “I have invented a better chisel. I've invented a thing that goes like this. I'm going to patent it.” He would realize that it was workers and workmen and handicraftsmen who were inventing the really useful tools.

He wanted to make this systematic. We would say there was always anthropogenic progress. In 1630, they realize there is anthropogenic progress. They think there hasn't been.

They think they're beginning, and that history up until this point has been stagnant, but now it's going to suddenly be full of invention as, for the first time, there will be deliberate anthropogenic progress.

Really, we would say there always was, and that it's accelerating. At this point, we realize it and articulate and describe it. You've probably seen lots of graphs of history with the hockey-stick graph structure, where it's flat for a long time and then zhoops up. They'll put that zhoop after the invention of the scientific method. It depends on what we're graphing and how much you zoom in or zoom out.

It's true: we do get to inventions that result in enormous increases in population 150 years after Bacon. Would we have anyway, even if it hadn't been systematized? Probably a bit later, and we would have a slightly flatter hockey stick. But we would still have hockey-sticked. In the same way, when you put mice on an island without mice, they breed and they breed and they breed and they breed and they hockey-stick. Humans would also have hockey-sticked.

But would we have hockey-sticked later? Would we have hockey-sticked with more pain? When mice hockey-stick, they also starve to death and eat each other. We haven't done that yet. Go us.

Was that science? Probably. There are a lot of factors to it. So is it true that everything accelerated after 1620? In one sense, yes. In another sense, it's a continuation of a curve that was already curving.

4. Why the industrial revolution didn't happen in Italy

I think you might have answered a question I was about to ask. The book you recommend on your website, The Renaissance in Italy—I keep forgetting the name of the author. Italian names are tough: Guido Ruggiero. At some point, he has this question: Look, in Italy, as you mentioned, in Venice, they've really scaled the printing press. As a result, you have the metalworking for fine typesetting.

Separately, milling technology for water mills and windmills is advanced, along with gears for watches. So he asks, why didn't Italy have the Industrial Revolution? I wonder, do you stand by the answer you just gave, or is it a different theory?

Part of it. But another is, we cannot underestimate how much richer per square meter Italy is than everywhere else. Italy is the breadbasket, and it's also the center of Big Oil, which is to say Big Olive Oil, which was both fuel oil for light and industrial oil for production, as well as cooking and eating oil. And the other major, major industry of the period was Big Wool.

If you're already the center of Big Finance, Big Wool, and Big Oil, do you need an Industrial Revolution? You're already economically on top through the power of agriculture. It makes sense for it to have been a sort of industrial backwater area. What was England producing? Crappy-quality wool?

England was so aware that it couldn't process wool into high quality without masses of olive oil, which it couldn't produce, that England just exported its crude wool to Florence in order to have Florence, with its olive oil reserves, produce the fine quality. Think about how a wool suit isn't itchy, but a wool blanket often is. That wool suit isn't itchy because lots of olive oil went into the process of producing it, at least at premodern tech levels. So do you want England to produce your itchy wool that people will only pay a small amount for, or do you want to export it?

It makes sense for it to have been somewhere industrially ambitious that wasn't already economically on top to have done it. That's one reason that industrialization doesn't kindle in Italy. Italy is agricultural land and a finance world. It doesn't feel like it needs a new industry.

Another factor is mining. This land is more valuable as a farm than it is as a mine. You don't want to rip it up. Another is that it's so subdivided because those rich cities are still mostly independent, whereas a centralized crown in England is more able to pass legislation to facilitate a massive transformation.

No city really wants to be the one where the giant industrialization is happening. It's awful for the city. Note that the industrialization of the Industrial Revolution was mostly outside of the wealthier centers of England, in the second-tier towns. They grow massively into huge industrial areas like Lancaster. So those are a plural bunch of reasons.

But I would have also thought that the competitiveness between different Italian city-states would have made it so that if they got better textile machines before you, it's a disaster because they're right there.

This is not going to sound plausible to anybody, but it's true. We've been looking at some documents recently which pretty much confirm that they did figure out how to make industrial looms in the 1400s, and they didn't want to. They wanted to make luxuriant artisanal fabrics. This, by the way, was another interesting thing from the book.

With the first printed books, there's not this market of commodity things that are produced cheaply, where the average person is going to be like, "Oh, if I can get this for $10.99, I'll go buy it." So they're trying to make this thing look like it was produced as artisanal, luxury-grade.

5. The Library of Alexandria isn’t where most ancient books were lost

Right. The first printed fonts look like handwritten scripts and often have a blank space to illuminate it, so that it looks just as fancy as manuscripts. One thing I wanted to ask you, back to the printing press: not only does printing get cheaper, but around this time, paper itself also gets cheaper. So not just reading, but writing gets cheaper.

Do you as historians see a marked change in this period in the amount of records that are taken and, as a result, our understanding?

Anton Howes

A huge amount rests on whether you have a cheap writing surface. Rather than looking first at the Renaissance, let's look at what we think of as the fall of Rome. One of the biggest things that happens there is that Western and Northern Europe lose access to papyrus. Papyrus is the cheap writing surface of antiquity. It is an easy, plant-based writing surface.

You take this tall, thin water reed that is fibrous like asparagus. You slice it into ribbons. You set them out in the sun, a bunch of them parallel to each other, sitting on a stone like noodles. You put a second row of noodles perpendicular to that on top, and then they dry in the sun, and they are naturally sticky. They stick to each other. They produce a sheet. Practically no labor has gone into this. You've sliced, you've laid out, boom.

Papyrus is a very inexpensive writing surface, and this is what enables Rome to have a bureaucracy and to have libraries in any midsized city. People can send letters back and forth. There can be enormous tax records. Sometimes when Egypt and Rome are at war, Egypt will be like, "No, we are angry. We'll stop exporting papyrus." No papyrus to Rome, and then Rome's infrastructure will fall apart overnight because you can't do anything if you can't write stuff down.

Papyrus is a warm-weather plant. It is killed by frost. You cannot grow it north of the frost line. So in France, Spain, and even most of Italy, you can only grow papyrus down at the very tip, in Sicily. Without papyrus, what you're writing on is a dead sheep. If you think of the price of a head of lettuce and the price of a leather jacket, you're understanding the difference between a sheet of papyrus and writing on a dead sheep.

Every page of a medieval book is as expensive as that much of a leather jacket. A handwritten medieval book on parchment costs as much as a house, so that a small pocket copy of a book costs as much as a studio condo. A big, illuminated, fancy Bible—you're spending on that what you would spend on a villa in the countryside. This is an enormous expense.

To have a library is to be not just rich, but mega-rich. Only the wealthiest cities contain anybody who has a library. The great library of the University of Paris—the library from Europe's perspective—has 600 books. There's definitely more than 600 books in this room. Every kiosk at an airport selling Dan Brown novels has more than 600 books. This is nothing.

At the same time, in the Middle East, sultans have libraries of over 1,000 books or 5,000 books. There are libraries in sub-Saharan Africa with thousands of books. There are libraries in China with thousands of books because they have cheap paper, rice paper. The Middle East has papyrus. Europe, and only Europe, is writing on a leather jacket.

What changes around this time? How is Europe able to get paper?

Anton Howes

Still zooming in on the fall of Rome. Rome had lots and lots of books on papyrus. They start falling apart because papyrus is brittle. Most of our knowledge from antiquity is not lost at the burning of the Library of Alexandria. It's lost between 400 and 600 A.D., when the papyri are falling apart.

Here you are with a library of 1,000 books, and you can only afford to make 100 new books. You have to choose which 100 of these 1,000 to save because there literally is not enough industry on your continent to make enough leather to copy down all this text. You have to pick. The majority of what we lost from antiquity, we lost then. We lost it when the papyri were falling apart.

This also distorted what survived because most of the copying out was done by monks. When you have 1,000 books and you can only save 100 of them and you're a monk, you're like, "What will I save? I know, Saint Augustine. I love Saint Augustine." This is why we have more surviving work by Saint Augustine than the entirety of all pagan classical Latin.

The subjective tastes of the people in power at the moment the papyri were falling apart ended up being an unintentional moment of censorship that biased what survives from antiquity. Paper technology hits Europe in 800 A.D., so we're talking about a 400-year famine of a cheap writing surface.

Paper is nowhere near as cheap as papyrus because you need to gather rags from used clothing. You immerse them in water, and you beat them violently using a mill for a very long time until they become a pulp. You then scoop that pulp up on a screen, and the fibers lock together. It's sort of a slurry that looks like grits. You lift up the slurry, and it locks together into a sheet of paper.

It's not as cheap as just growing papyrus, and it requires much more labor. You have to build a paper mill. If parchment is a leather jacket and papyrus is buying a head of lettuce, this is somewhere in between.

What's in between a leather jacket and a...? This feels like a trick question.

This is somewhere in between: getting yourself a dozen frozen, prepackaged meals, which are complex and have many ingredients. A lot of industry went into producing the actual packaging, more so than a head of lettuce. So it's 10 times as expensive, but it's still 1/10 as much as the leather jacket.

Paper comes in, and people are very wary of it. Paper is clearly not as strong as parchment. Parchment is really tough stuff. People start using paper for rough drafts, letters, and sketchbooks.

When you're doing the sketch before doing a painting, you might do that on paper. But Europe has paper for 400 years before the earliest state document is ever written on paper, to give you a sense of how wary people are of it. It disseminates slowly. It's still expensive. It requires industry and production, but it is 1/10 as expensive as leather.

Paper disseminates slowly through Europe. Again, this is one of these things where there was always technological change, and all technological changes are gradual. Paper comes in in 800. It's being trusted by 1200. When printing begins, they're printing on paper, but they even print on vellum.

If you're a really rich person, you would be like, "Please print 2 copies on vellum for me." Dukes like the Dukes d’Este—Isabella d’Este, the sister of the duke who walked around buck naked to show off that he could—specially ordered all of her books to be printed on vellum even when the rest of the print run was on paper.

These are the very books being produced in Venice by the apprentices of Gutenberg who ran away. At that moment in the 1490s, if you're really rich, you might be invested in these newfangled printed books, but you're still not trusting paper, even though paper has been there for 600 years at that point.

So again, there was gradual adoption of technologies and gradual trust in paper. They're still using parchment for things, gradually less and less, but substantially over the course of the 1600s. You can even find things written on parchment in the 1700s and 1800s. British Parliament still did its records on parchment up until 10 years ago, and the Vatican still does its official records on parchment now.

This is a digression, but the numbers of how expensive a book is didn't make sense to me just based on how much scribe time it took. You say it's $600,000 per book, and then separately, it's 5 months of scribe time. I'm like, how much are the scribes getting paid? But if it's the paper, what changes with Gutenberg?

The paper and the ink. But a lot of it is scribe time.

But Gutenberg still needs paper, right?

Yeah, Gutenberg needs paper. That's why he goes bankrupt. He borrows the equivalent of about $1.5 million to buy paper, and then doesn't make back $1.5 million worth of material when printing it.

This is what makes printing a risk. You have to start buying the paper up front. You need to buy it in a big lot so that it matches, because people don't want the paper to suddenly be a different color within their book. You're investing a lot up front, and you're not getting anything back until you produce this slow print run, which is why printers start printing pamphlets.

They can have 1 press that's slowly printing a valuable book that will take 6 months to print. Next to it, they have another press that's printing pamphlets, where in 2 days they've printed a fashion report on what everyone was wearing at the royal wedding, which they can sell right away. It's much cheaper, but it means they have something they can sell 2 or 3 times a week.

So you have the pamphlet following the book, printing cheap news, printing scandal rags.

Why is it cheaper? Because the material is cheaper?

Just because it's only 5 pages long.

Oh, I see. Got it.

I could grab one if you want to see one. So if we look at some examples, I'll show you these one by one. For example, this is a pamphlet. Naked pages, short text, hand-stitched together. It would take 2 or 4 days because you print the front side and then the back side.

It's cheap. It's ephemeral. You print 1,000 of them. You sell a bunch around the town. You sell a bunch to news writers who are going to and from other cities, who will buy them and bring them to the next town. If you've printed news in Milan, people who are going to Florence will want to buy your news to go there.

It might be a report of a siege. It might be what people were wearing at the royal wedding. My favorite title of a pamphlet was "The Scandalous Tale of a Doctor from Padua and How He Seduced His Maid, Murdered His Wife, Murdered the Maid, Cut Out Her Heart and Ate It, and How He Was Justly Punished by God." That was the title of the pamphlet.

These things circulated around. Some of them were nonsense, some of them were real news, and most were combinations. But you can sell something like this cheaply in a couple of days. Often they would have a cheap blue cover. You have seen this color before. This is the color of laundry lint, because fundamentally laundry lint is what paper is.

You take rags of old clothes, you put them in water, you beat them until they become a pulp, and you skim it out with a sieve. Laundry lint is what rag paper is. If you don't bleach it, it's this generic blue-gray color, which is sort of the average color of what human beings wear.

That's a copy of The Gentleman's Magazine, another example of technology taking a leap forward in the 18th century. When they invented the newspaper, they immediately had the problem of, "Oh, no. Newspapers contradict each other. We don't know what's true. We have to fact-check stuff."

That one has a great fold-out. I think there's a procession or something.

That is what everybody wore at the state funeral. Instead of photographs, we have this fancy, "Here is what everyone was wearing at the state funeral." Very exciting.

Your laundry lint, if you don't bleach it, remains the color that it, on average, was. In the 18th century, they have newspapers. The newspapers are reporting news, but they don't quite say the same thing as each other. The problem becomes, how do we know who to trust?

The Gentleman's Magazine was developed, and every week they would publish a roundup of that week's news, saying what each newspaper said about it, where they contradicted each other, and analyzing who's right and wrong. It was the fact-checking.

This is the first magazine. It invented the word "magazine" being used in this context. It was an intellectual response to the fake-news problem of how we reconcile what happens with newspapers.

You see these many iterations: they invent the printing press, then they invent the pamphlet, then they invent the newspaper, then they invent the magazine to cope with the newspaper. The newspaper is invented to cope with the pamphlet because you don't know whether to trust "The Scandalous Tale of a Doctor from Padua and How He Murdered His Wife." Is he real? We don't know.

But if somebody publishes a newspaper that serially prints news every week, they have a reputation. They have to be respectable. You're not going to subscribe to them if you catch them printing nonsense. The serial nature of a newspaper was a form of accountability that made people willing to trust it over time.

The newspaper is a way of fact-checking the pamphlet. The pamphlet is a way of making money while you're printing your longer book.

I will also let you have a look at papyrus.

Thank you.

You can see the plaid pattern of the papyrus because it is made of 2 layers of strips. And there's a papyrus scroll. That's modern papyrus.

The thing about papyrus is that in addition to being cheap, it's very brittle. It works better in a scroll than it does folded over because the folded edge cracks really easily. If you try to make this into a codex book, it's going to be very fragile.

Here you go. This is a real 17th-century letter in absolutely indecipherable handwriting.

On parchment?

On parchment. You can even tell, because that's cheap parchment, which side was the outside of the animal and which was the inside. The handwriting is in some sense bad, but it's also very well aligned—tiny and precise.

But here is good parchment. It is hard to believe that it's animal skin. These are pages from a book of hours from about 1480, individually hand-calligraphed. You can see that one has a hole through it. They wrote around the hole because it's too valuable not to use that sheet.

These are paper-thin. You can barely tell, if you look carefully, which side was the outside of the animal and which was the inside, because one side has tiny little speckles of pores.

Where is this from?

A book of hours. This is probably a French book of hours. A book of hours is a personal prayer book: Bible quotes, objects of meditation. The book would be fat and small.

This was the most common manuscript in the Middle Ages. You would carry it around in your pocket, and you'd pull it out at different times of day for personal prayer. But it also has big margins so that you can take notes in it, write down addresses, and have friends write notes in it. You use it almost like a day planner.

It's the smartphone of the period, in which you make all your notes or write down people's names. You might have celebrities you meet sign your book of hours. All sorts of neat things go into the margins as you use this to organize the day.

That would be extremely interesting as a collector's item—random people's book of hours and what kinds of things they recorded.

Oh yeah. Think of a leather jacket, but how much more industrial effort went into making leather literally paper-thin like this. Huge amounts of industrial effort go into making the pages of such a book.

My favorite example of this kind of distribution and diffusion taking longer than you would think for a very fundamental technology—well, this is now my favorite example, so my second favorite example—is oil.

I interviewed Daniel Yergin, who wrote this big book about the history of oil. In the 1860s, Drake strikes oil in Pennsylvania. It's in the 1910s that the car is invented and the internal combustion engine is put into a thing which you sell millions of copies of. Until then, oil is just used for kerosene, which is just for lighting. The actual gas is just thrown away. In fact, when the light bulb was invented, people were wondering whether Standard Oil was going to go bankrupt because the main use case had gone away.

Oh, neat.

I always think of Julius Caesar's description of Britain when the Romans first get there. He says, “The people of Britain are so poor, they can't afford to burn wood, so they burn rocks.” We know he's talking about coal.

Oh, I thought it was satire.

No, he's talking about coal. They had coal in the days of Julius Caesar, but they didn't figure out its massive industrial utility until many, many years later. There is this interesting question of why the Romans didn't have the Industrial Revolution, because they had these huge silver mines in Spain and elsewhere, but no coal.

You have the Industrial Revolution when you feel you need to. That's the thing about Gutenberg as well that a lot of people don't think about. People are like, “Gutenberg was an inventor and invented a thing, and then it had an impact.” No. He was living in the middle of a library-building boom in which there was a huge demand for books that spiked. He invented the invention in response to that cultural change.

It isn't by chance that we got the printing press in 1450. There was a huge boom of library buildings starting in the 1410s, and inventors were trying to figure out ways to make books cheaper. They were making smaller books. They were using paper more. Paper surges before the Gutenberg movable-type printing press.

So Gutenberg isn't a random genius out of nowhere. It was the moment that people needed more books. We were going to get the invention.

6. The Inquisition accidentally invented peer review

One thing you say in passing in the book is Martin Luther comes up at the exact right time, because you've got Savonarola in the 1490s, and he's another prophet type. I guess he's the modern analog of somebody like Khomeini in Iran, setting up a theocratic government, but too early. Machiavelli, you say, is too late because the censorship is already in place. What is the censorship that is in place by the time of Machiavelli? What is the alternative world?

Machiavelli, remember, is contemporary with Luther. It's just that he circulates his stuff very briefly and very privately. He doesn't want a pamphlet version of his ideas out there because he only wants Florence to have it.

Luther hits the sweet spot when the pamphlet distribution network had just developed. When Savonarola printed pamphlets, they only circulated around Florence and its neighbors, Siena and Pisa. It took months for them to get farther. His movement was quickly crushed.

When Luther makes the 95 Theses public, they're in print in London 17 days after he releases them in Wittenberg. The pamphlet runners go “foom, foom, foom” and get the news there, and things are printed overnight and come out that fast.

But it seems like you're hinting that within the next 2 decades, there's a new censorship regime across Europe.

A new censorship regime responds. The censorship regime is very effective at shaping what is printed in books, but can never keep up with pamphlets. In the same way that the government can pressure CNN, the government can't pressure random people on a social media network. You're not going to be able to keep up with that speed.

One of the funny problems that the Inquisition always had when trying to persecute printers is that printers worked in the information-distribution industry. They were the people who paid the news writers, whose job it was to move as fast as humanly possible between cities. That meant that news always reached them first.

If a printer was ever convicted by the Inquisition, they would find out before the Inquisition could possibly get there to arrest them. The Inquisition never succeeded at arresting printers. They'd always skipped town by the time the Inquisition got there, because if you employ the news writers, you find out first what's going on. The Inquisition can't keep up.

When we look at censorship, there's an intersection of 4 factors as to whether censorship is possible. One of them is law: Is it legal for the censorship to happen? Another one is the technology. Is it actually possible to censor this thing?

You cannot censor whatever moves the information fastest, because it will move the information faster than you can move. Even if that one printer had to skip town, he will set up shop somewhere else, a new person will take over his shop, and the information will still move.

So pamphlets become unpoliceable. You can try to police them, you can partially police them, but keeping pamphlets from moving around—they're anonymous, they're quick, they're produced overnight, they move quickly. You just can't keep up with them.

Couldn't they just punish print shops for publishing things? Just say, “This is what we like, and if you do something we don't like, we'll punish you,” which is how censorship in China works, for example.

They did. So the printer skips town. The printer moves to the next town. There is a cost to that. There's a human cost to evading that. You've had to leave your home and friends behind and move to a new place, but they don't get you. It's also very easy to deny that the pamphlet came from you at all.

The print industry proves very difficult to censor, and we're experiencing the same thing with social media. Everyone is like, “Censor the pornography on this social media channel,” and they're like, “We just can't. It's too fast. There's too much.” Or, “Censor the hate speech.” “We just can't. It's too fast, there's too much.”

There are too many pamphlets, and they could crack down on 1 particular pamphlet shop. We have records of this. There's a brilliant analysis in Anton Matytsin's book, The Specter of Skepticism in the Age of Enlightenment. He has a great description from the notes of a raid on a clandestine bookshop.

This wasn't the printer; this was the underground bookshop that was selling illegal books, and they're raided. It has all the details of how angry the people were about different things that the shop had.

So there was censorship and there were crackdowns, but it was a censorship that could not actually prevent circulation. It could restrict it, it could make it harder, it could make it scary, but it couldn't prevent it.

Before books become cheap, unless you're fantastically wealthy, you're reading the same couple of books—if you've ever read a book—again and again throughout your life. Cosimo de' Medici's father owned, I think, 12 books. I want to understand the intellectual significance of rereading the exact same book again and again.

Maybe the reason Petrarch loved Cicero so much is, imagine reading the same book 20 times, hitting the same joke again and just meditating on every single point. There's got to be a difference in intellectual culture as a result of treating these things as the equivalent of the Bible.

You really feel like you get to know the person intimately. You develop a personal relationship with the ancient author. You are participating in a conversation across the diaspora of time. It's a one-way conversation. You're responding to them; the future will respond to you. But there is a great deal of intimacy.

Petrarch talks about his friend Cicero and being betrayed by his friend Cicero. He finds new works of Cicero that he hadn't read, including some of Cicero's letters in which Cicero is not following his own Stoic philosophical precepts and is being petty, yelling at people about real estate, and getting all upset after his daughter's death.

You know how people get manic when there's been a death in the family and start quarreling about everything? Cicero gets like that, and Petrarch is heartbroken. To him, it means even the wisest man in history could not conquer that urge to become irrational and petty in the face of grief.

If even Cicero became irrational and petty in the face of grief, does that mean humanity is doomed to forever be irrational and petty in the face of grief? He talks about Cicero breaking his heart and his foot, because the book fell on his foot and broke it, and he got a bad infection, and he was bedridden for months.

Totally different topic, but in 1492, Columbus comes to the New World. They discover the New World. What is the reception of this news?

I was just at a conference a week ago in which we confirmed that there's a Vatican document from 1100 or maybe 1200—I forget the exact year—that recognizes the existence of Vinland, i.e., Canada, where they got the information from the Vikings.

Oh, interesting. They thought it was just a little thing, but yeah. So they're rediscovering the New World. Would it be the equivalent of finding out there are aliens today? Why wasn't it considered more significant? Why wasn't the consensus, “This is the main thing happening right now; we've discovered the New World”?

When I teach my class on the 1490s, the students, many of whom are American, always have trouble wrapping their heads around people thinking that the New World isn't a big deal. A big part of it is that they find the Caribbean islands, and they find the coast, and they think this is small.

The way I put it to my students is, the news comes back: we've found something across the water to the west. It might be even as big as the Canary Islands. They've found something, but they don't realize they've found something the scale of Europe and Africa.

Actually, it's not as big as Europe and Africa, but they found something humongous. That's part of it. Another part of it is, no matter how big and important something far away is, it's hard to bring your mind out of the petty squabbles that are happening right around you, especially when they feel like life or death. If it's 1492, what is happening? France is about to invade Italy.

Europe might be embroiled in the largest war it’s seen in 50 years. The papacy has just been taken over by Spain. Spain is suddenly trying to throw its weight around in Europe in a way that’s unprecedented. The Ottomans have just invaded Italy and Hungary and might be coming again. Also, over there, there’s a new thing.

“Okay, great. We’ll worry about that when we’re not having 3 wars at the same time.” But guys, we’re having 3 wars at the same time. Oh my God. And then Martin Luther hits Europe like a ton of bricks when they still haven’t even figured out that this is a continent and not an island.

In the same way, if you’re in a country and it’s having a tumult, you worry a lot about its tumult, even if a larger tumult is happening in a faraway country. It’s hard to bring your mind out of Europe at crisis to be like, “Hey, this is a thing.” The other is that they’re inventing lots of new things, and it falls into the sphere along with the rest.

They’re discovering the existence of sub-Saharan Africa, where they thought there was basically one country’s worth of stuff south of the Sahara—Ethiopia and nothing else. Then they’re like, “Oh my God, there’s a whole big thing that sticks out.” They’re also discovering that the heart is a pump. That’s a bit later, but they’re discovering all sorts of stuff at the same time.

The discovery of the New World, especially when they realize how big it is, becomes an intellectual challenge where they say, “Wait, does this mean all the maps we’ve had are wrong? Does this mean the ancients were wrong about geography? Does it mean the world is a lot bigger than we used to think the world is?” Let’s worry about that the same way we worry about revolutionizing our mathematics and figuring out that the sun doesn’t go around the Earth. These are things that are paradigm-shifting.

But on the other hand, does it matter whether the sun goes around the Earth or the Earth around the sun when the French are invading right now and we need to get the defenses going, and there’s a giant civil war happening, and we’re about to be betrayed? It does matter, but it also doesn’t matter. Any decade is concerned by its tumults and often fails to recognize the importance of what’s around it. That’s true of every decade.

One fun game when I study the history of censorship, which I work a lot on—my next nonfiction book is gonna be a book on the history of censorship—is that whatever they’re looking at, they’re always wrong, from our perspective, about what they should be worried about censoring. If we had a time machine and our goal was to go give them advice, here we are in the French Enlightenment: Voltaire and Rousseau and the Marquis de Sade and La Mettrie’s articulations of materialist atheism are flying around Europe.

What is the Inquisition worried about? It’s worried about Jansenist treatises about the nature of the Trinity. Jansenism is a Calvinist version of Catholicism. Do you want to have an incredibly terrifying authoritarian God who hates you and tells you that your soul is a worthless spider that deserves to be hurled into fire, but also have to obey the arbitrary pope in Rome? Then Jansenism is for you. It has all the grimness of Calvinism and all of the authoritarian centrality of Roman Catholicism.

This was a heresy that was abroad in the Enlightenment, and they are so much more worried about Jansenism than they are about Voltaire. Remember that very chapter in Matytsin’s book I mentioned where they are raiding the clandestine bookshop. They’re like, “Voltaire, fine. The banned Encyclopédie, which is gonna revolutionize all thought in Europe, fine. Letters of Diderot, Rousseau, fine, fine. Jansenist treatises about the nature of the Trinity! Throw the book at these guys! This is the worst thing!”

They really are obsessed with this incredibly petty minor heresy to the degree that when the Encyclopédie is banned by Rome, Paris is commanded to ban it. Paris loves this book. The king likes this book. The queen likes this book. She’s on record saying it was so cool being able to look up the technology that was used to make her silk pantyhose. She just loves it. Everybody loves it.

France allows it to circulate despite its controversial content. But Rome says, “No, you must ban this book.” So they agree they’re gonna have the ceremonial burning, and they march the Encyclopédie up to the fire. Then they get some Jansenist treatise about the nature of the Trinity and burn those instead, because they don’t want to burn the Encyclopédie. They love it. They want to burn this other thing.

This is always true. If we had a time machine for the Inquisition in the 1540s, we would say, “Guys, Machiavelli—he’s really important. He’s really revolutionary. You gotta be looking at this.” Or we would say Lucretius’s De rerum natura, which I did my dissertation on.

Many people are familiar with Greenblatt’s book, The Swerve, which credits a lot of change to the materialist science that this poem articulates. There’s a much more complex story, which is told in my book and refers to Greenblatt’s. If anyone enjoyed The Swerve, you would really enjoy the more detailed zoom-in that Inventing the Renaissance has. But we would say, “Guys, you should censor this.”

We literally have letters of inquisitors writing to each other saying, “We don’t need to bother censoring Lucretius. Only learned people can read it, and they know perfectly well that the false stuff is false, so it’ll just circulate and it’s fine. What we need to worry about censoring is all of these fine minutiae of Protestantism.”

The 1545 edition of the Index of Banned Books says in its introduction, “We shall put the names of arch-heretics in all caps.” When I first read that, I was like, “Ooh, I want to see all my favorite arch-heretics be in all caps.” I eagerly flip to M, and Machiavelli is not in all caps. He was not important enough from their position.

The all-caps authors are all minor Protestant theologians. They’re all people like Calvin and Zwingli and Luther and Melanchthon. They’re all doing stuff that we would say does not matter. But an era is always wrong about what ideas and what circulation and what changes are the really big ones, and is always much, much more worried about, “Oh my God, the prince of Spain—which princess is he gonna marry? This is going to determine whether Spain is or isn’t annexed by Germany. This is the most important thing that has ever happened in the entire stream of time.”

People are like, “We’ve discovered another continent,” and they’re like, “We don’t care. We just wanna know who’s gonna marry Charles.”

That’s a very profound observation. It was really interesting to learn from your book that, of all the thousands of people killed during the Inquisition, one guy was executed for atheism—science-related stuff. And even he had these ideas of reincarnation.

I think probably the number executed for atheism would be about 100. There are 12 total trials of scientists about science. Galileo is one. Giordano Bruno is one. Giordano Bruno is the only one executed. Of those 12 trials, only 3 were convicted.

There were hundreds of thousands of trials for Judaizing, which is theoretically contaminating Christianity with Jewish thought, and all of these other minutiae of oppression and segregation of populations. There were executions for paganism, meaning practicing your indigenous religion in a colonized space—hundreds of thousands of executions for that, and 1 for science.

I recently got interested in the story of Kepler just because the way he discovers the laws of planetary motion is so whimsical, with the theory of Platonic solids. While he’s going through Brahe’s data and coming up with the laws of planetary motion, he is the imperial mathematician for the Habsburg emperor, which basically means that he’s doing astrology for a general: Will we win the battle or whatever?

Then he gets excommunicated, not for the laws of planetary motion, but because he’s a Lutheran. In fact, his mother is tried for witchcraft. Again, it has nothing to do with science; it’s just because she’s also a Lutheran.

Milton, of Paradise Lost fame, wrote our first big defense of the free press, the Areopagitica. This is in the moment in the early 1600s when England doesn’t yet have systematic censorship law. It has ad hoc, “Hey, this book is bad,” but it doesn’t have systematic, “You must submit all books to a censor,” the way the Catholic world does by that point. The Catholic world developed it in order to fight Protestantism.

There’s a lot of support for creating censorship in England at the time because there’s anxiety about Papists plotting against our nice non-Catholic country, trying to undermine it. There’s a general feeling of anxiety. There’s also deliberate moral panic whipped up by politicians and power-seeking people who whip up a deliberate moral panic about books, the same way in 1954 there was a moral panic about comic books or the same way there was a moral panic about Dungeons & Dragons in the 1990s.

There’s a moral panic about scary and dangerous books and pamphlets. So there’s a movement to create state censorship for the first systematic time in England. Milton writes this big treatise about why freedom of the press is important, the Areopagitica. It’s a beautifully written rhetorical piece that presents the importance of how we must trust truth to rise purely to the top.

We must let free voices move, otherwise you’re gonna create a situation where people are writing for the censor first and for the public second.

It will constrain people's thoughts in the way that we know chilling effects and fear do. It's a beautiful treatise. He fails. The censorship regime passes. Paradise Lost is published under the censorious regime.

It goes through the censorship. The one line they tell him to change is about astrology. They're like, “It's perfectly fine having Satan be your charismatic protagonist and God be kind of a jackass, and also having Satan spout ferocious anti-monarchical rhetoric copied from revolutionary pamphlets that are circulating in the British colonies, so that he's actually parroting republican, anti-monarchical rhetoric, very dangerous stuff in the treatise. That's fine. But this one line about a comet causing a thing to happen—no, no, no. Astrology is gonna confuse people's souls.” You're like, “Guys, speaking as a time traveler, you're so wrong about what you're censoring.” They always are.

You have one sentence which I couldn't trace down, which I found very interesting. You said, “In the late 17th century, the most extensive library in all of Europe is the one in the Vatican run by the inquisitors.”

Not the library—the most extensive experimental laboratory. Daniele Macuglia is the scholar there. That's from his dissertation. I think it's been published now, but I don't know if it's actually out in English. It's out in Italian.

He works on the Inquisition and the immediate aftermath of Galileo. They saw themselves as guarantors of truth and of accuracy in information. So they decided after Galileo that they had a duty to verify the truth of the books that they were sent to censor. If people were going to be doing mechanical experiments, they needed to repeat the mechanical experiments to see whether they were true.

So they effectively invented peer review, which is to say they invented a second laboratory trying to recreate the results of the first. There are these amazing people who by day are inquisitors and by night are going home to write their own scientific treatises as they do these experiments. It's not what we expect, but history is never what we expect.

Seems like a good place to close. Ada, thank you very much.

Thank you.