Broadsheet

So, a break from political and policy madness. Along with everything else going on, there’s what looks like a revolutionary technology spreading through our society, which everyone calls AI, even though it doesn’t (yet?) look like the kind of artificial intelligence everyone expected.

However, in thinking about this revolution, and the economic role of technology in general, we have a problem: economists in general don’t know enough about the technology to make an informed judgment (and technologists aren’t great at economics, but that’s for another day.) So I wanted to talk about what’s happening with one of the few economists who has really invested in understanding information technology: Stanford’s Erik Brynjolfsson. Here’s our conversation; transcript follows:

TRANSCRIPT: Paul Krugman in conversation with Erik Brynjolfsson (3/20/25)

Paul Krugman

Hi everyone. This is my latest video conversation. And now for something, again, quite different. I wanted to steer away mostly from the current political policy environment and towards what is certainly one of the biggest stories, which is AI, but just generally technology. So I'm recording a conversation with Erik Brynjolfsson, who is one of the few economists who has really followed technology as opposed to just sort of plugging it into their models, which is what I do.

If you're wondering, I’m actually in a hotel room in Belgium. I'm committing the cardinal sin of a video interview with a bed in the background because it's a pretty small hotel room but here we are. Hi Erik.

Erik Brynjolfsson

Hi Paul, good to see you.

Paul Krugman

I've been meaning to get you for a conversation. There were some hitches there, but if it weren't for all the other things happening in the world, technology would be one of the biggest stories out there. Certainly very interesting things are happening. As I said, you're an economist who actually knows something about technology, which for lack thereof hasn't stopped some of our colleagues from having strong views. But why don't you tell us a bit about your background and how you came to be that guy?

Erik Brynjolfsson

Sure. Well, Paul, you probably don't remember this, but when I was an undergrad, you came and gave a guest lecture at Harvard. That's when I first got to know you. And at the time, I was kind of having one foot in technology and one foot in economics, trying to decide between the two. They asked me to teach a course at Harvard Extension School. So along with my college roommate Tod Loofbourrow, we taught a course on building expert systems and one on applications of artificial intelligence.

We started a company called Foundation Technologies in homage to your and my favorite science fiction author, Isaac Asimov.

Paul Krugman

Oh my gosh, I didn't know that. Yeah, okay.

Erik Brynjolfsson

So we were building these systems back then. And then I decided I really needed a graduate degree to get in a little deeper. And so I decided to go to MIT where I thought I could maybe do both AI and economics at the same time, but it didn't really work out and I had to choose. And I went more the economics route, but continuing to be really interested in technology and what I was doing. And I was lucky enough to have Bob Solow kind of mentor me. And you may remember back in the eighties, there was this puzzle of, as Bob Solow put it, we see the computer age everywhere except in the productivity statistics and I called that “the productivity paradox.” So we were wondering what all this technology was doing. And so my first real big paper was trying to address that puzzle about technology and productivity.

Paul Krugman

Okay, great. By the way, not everyone may know, but the foundation novels by Isaac Asimov involve mathematical social scientists who save galactic civilization. And when I was growing up, I wanted to be one of those guys and this is as close as I managed to get. And the productivity paradox is something we all talk about. Let's just talk for a second. Economists generally, starting with the work of Bob Solow—the great Robert Solow, sort of the founder of growth theory in economics—have always given a really crucial role to technological progress.

Erik Brynjolfsson

Yeah, I think what we all learned in grad school was that Bob Solow back in the 1950s, what he really got his Nobel Prize for was showing that, you know, we're not necessarily working more hours or even having that much more capital. That's not what's driving our higher living standards. It's mainly that we have much better technology than people did in the past. So technology is the main driver of living standards. And he just kind of stuck it in the model as this extra variable and off we went with better and better technology. Since then, a lot of people have tried to flesh that out a little bit in more detail. One of the things that are connected to AI is this class of technologies we call General Purpose Technologies. Economists just used to call them GPTs, but the AI people stole that acronym from us. But General Purpose Technologies are things like the steam engine, electricity, and I think AI. And that's actually what drives most of the progress in our living standards. So that's kind of behind my focus on that set of technologies.

Paul Krugman

You say, Bob Solow pointed out—I'm not sure when he first made that remark, 1987?

Erik Brynjolfsson

1987 in a little article in the New York Review of Books, yeah.

Paul Krugman

Not many young people realize how revolutionary IT seemed to be. When I was in graduate school, using the computer meant handing a box of punch cards to the high priests behind the glass wall at the mainframe and then waiting an hour for a printout to come back and you made one wrong key punch and you got this whole stack of hexadecimal. Anyway, you know, and then to the coming of desktop computing which is really...

Erik Brynjolfsson

Time magazine made it the machine of the year. I think it was 1982 because we were all being revolutionized by it.

Paul Krugman

Yeah. In terms of my own work, what it meant to actually do the work for a paper, it actually was revolutionary. Suddenly you could do all of your statistical work without having to go to the computer center at three in the morning.

But it wasn't really showing in the productivity numbers. What's your take on what happened to the productivity paradox? Because I have a version, and let me see if yours matches mine.

Erik Brynjolfsson

So, well, it went away in the 90s when we actually had roaring productivity. Productivity more than doubled to about 3% per year, which economists consider a pretty good rate. And part of that was the internet. Part of it was, I think, an even bigger part that's not as much recognized as large enterprise systems, these ERP systems from companies like SAP and supply chain management, customer relationship management systems, that started really changing the way business was being done.

And what’s really key is that these general purpose technologies rarely have a big effect all by themselves right away. It's usually after they start transforming the way business is done and companies rethink what they're doing. And that business process change, that re-skilling, that reorganization often takes some time before it translates into productivity.

Paul Krugman

Yeah, there's a classic paper, probably you cite as well, a Paul David paper on the dynamo of the computer, how it took decades before businesses figured out what to do with electricity. You have this innovation, and there was electricity everywhere, but it really wasn't doing anything until businesses figured it out.

Erik Brynjolfsson

Right. In the 1880s. He showed that companies started installing electric motors, but according to the records he went through, they didn't really have big productivity gains until about 30, 40 years later. The big change—to oversimplify a story—was that at first they just took out the steam engine, put an electric motor where the steam engine used to be, and nothing much else really changed. It took about a generation of managers to realize, wait a minute, electric motors can be light, small, medium, large, all different sizes, and you can lay them out by the flow of materials instead of having this one big engine in the middle of the factory. That new layout, which allowed for assembly lines and the flow of materials, that led to, according to Paul David, 100%, triple digit gains in productivity. But it really wasn't the electricity by itself, it was the combination of electricity plus new business processes.

Paul Krugman

Yeah. The six-story tall mill building with cramped corridors and overhead crankshafts and so on gets replaced by the sprawling modern factory with wide aisles. Around 1997, 1998, we were all saying, “Look, Paul David was right.” All it took was time and maturity, and we got this big surge in productivity. At least according to the numbers. I certainly thought we were going to see a much more sustained rise in productivity than we did.

Erik Brynjolfsson

Yeah, no, it then started fading around like 2005 or so. It dropped back down and since then it's been back down around 1.4% productivity growth per year, like maybe half of what it used to be. So that's been very disappointing and in a way it's a second productivity paradox. Along with Chad Severson and Daniel Rock, I wrote a paper called “The AI Productivity Paradox,” basically replaying some of those hypotheses and trying to understand why this new wave of technology

isn't translating into productivity gains.

Paul Krugman

Yeah, it's basically a decade of good productivity, you know, boring productivity growth that seems to be associated with IT, but it's like ‘95 to 2005 or thereabouts. It's really 20 years now that we kind of haven't seen, at least in the numbers, haven't seen those kinds of gains. And the iPhone came out during that period. Broadband internet basically comes out during that period. It doesn't seem to move the numbers.

Erik Brynjolfsson

Yeah, well, you said a couple of times, “at least in the numbers.” And so I think you're setting me up there to say something about measurement, too.

Paul Krugman

That's a really big issue.

Erik Brynjolfsson

Yeah, that's a big issue. Right now we're looking at screens. The average American spends about eight and a half hours a day looking at screens of various sizes. They're voting with their time that digital is a bigger part of their consumption than the time they spend on consuming atoms and services. So we're kind of transitioning to an economy where that's really important.

And GDP is an amazing invention, one of the great inventions of the 20th century, Paul Samuelson said. But one thing it doesn't do well is, it doesn't measure things that have zero price, with few exceptions. And so we're missing a lot of the digital revolution just by design. Zoom or Wikipedia or search, most Facebook value for end users, they aren't counted in the productivity statistics. There will be, of course, some electricity use or there may be some advertisers who benefit, but the consumer benefit is largely missing from our statistics. And as the economy becomes more and more based on digital goods and services, we are missing a bigger and bigger part. You mentioned the iPhone. Most of the stuff you consume on the iPhone, or a lot of it at least, you're not paying for.

And that means that it's largely invisible in the GDP statistics. And I should mention, just a slight technical note, productivity is just defined generally as GDP divided by hours worked. Sometimes you put other things in the denominator as well. But if you mismeasure GDP, you're going to mismeasure productivity just as much.

Paul Krugman

I can go back and forth on this, and I have, I guess. There's clearly a lot of unmeasured gains.

Watching videos of cute animals on YouTube or whatever is clearly a source of joy for some people. Watching actual musical performances is a source of joy for me. That's not going to show up in GDP at all.

Erik Brynjolfsson

Right. We're all listening to more and better music than we ever have in history, but that doesn't show up.

Paul Krugman

But the question always up for debate is, hasn't that been true one way or another for the enormous improvements in public health in the first half of the 20th century?

Erik Brynjolfsson

Definitely. Chad Stevenson wrote a good paper kind of arguing that yes, we've got mismeasurement, but also we used to have mismeasurement too. So you really need to kind of compare one mismeasurement versus another mismeasurement, which is hard enough just doing one of them, but doing two of them is pretty tricky. So that's one of the reasons that Chad and I wrote a paper together along with Daniel Rock to try to reconcile this. I think I've come around to the view that mismeasurement isn't the whole story or maybe not even the biggest part of the story. I do think that this reorganization is a really big part of the story, the reinventing of the economy.

The kind of reinvention that's going to be needed for the digital age is at least as big as what we saw in the industrial age. That said, I would love for us to do a better job on the measurement side as well. My team at Stanford, we've created a new measure of GDP, or of welfare I should say, called GDP-B which measures the benefits. It seeks to measure sort of the consumer surplus that's created by all these goods. So even if you pay zero for it as a consumer, you may still get significant benefit. And if you look at that side of the ledger, then the digital revolution is creating trillions of dollars of consumer welfare, even though we're not paying for it. So we are addressing that measurement side of it. One article about it just came out in the American Economic Journal of Macroeconomics this past month. But this new framework GDP-B, I'm hoping will be increasingly used alongside traditional GDP. As the economy becomes more digital, we'll measure not just what we're spending, but also the benefits we're getting.

Paul Krugman

Random thought here. A lot of these benefits, the unmeasured benefits, are kind of the consumer experience at some level. I'm sitting in Europe right now. The Europeans have been very upset that U.S. productivity has pulled way ahead of Europe over the past 25 years or so, even if a lot of the gains come from the consumer experience. People are absolutely as internet addicted, absolutely spending as much time on their mobile phones as Americans are.

Erik Brynjolfsson

So in a different paper, we did an international comparison. We picked 12 digital goods. At first I was surprised, but then it kind of made sense. What we found was that richer countries had a proportionally smaller share of their total welfare from digital goods than poorer countries or middle income countries. So, Mexico, Brazil, they actually had a bigger share of their total welfare from digital goods. And when I thought about it, it does kind of make sense. If you're poor, you're not going to be spending a lot of money on caviar, Rolls Royces, or even televisions. You're going to spend more of it on stuff that's free. You can consume as much free as anyone else, as long as you have a smartphone, which most people do. So it ends up being a proportionally bigger share of your welfare.

Paul Krugman

Yeah, actually if you think about that for individuals, Bill Gates, or whoever, gets probably no more or less pleasure out of stuff that's free than I do.

Erik Brynjolfsson

Yeah, exactly. Or then a working class person. And that's what we found. We looked at it both within zip codes within the United States, and we looked at it across countries. And digital goods tended to reduce inequality somewhat, just because they're available to almost everyone. We didn't have data from the very poorest countries. So I'm not sure it goes all the way down. I assume it doesn't if you don't even have a smartphone. But once you're at that basic threshold of being plugged in, then it tends to be a net equalizer.

Paul Krugman

Scott Bessent, the Treasury Secretary, just over a few days ago said, “The American dream is not having a flat-screen TV.” But you're saying in a way, kind of it is, or that a lot of the benefits really are a lot of economic growth.

Erik Brynjolfsson

Ha ha ha. Well, yeah, and that's why I'd love to get this GDP-B measure kind of systematized and have it start coming out every quarter. And then we could know for sure what's happening. It's entirely possible that as we switch around our consumption towards more digital goods, the numbers will look a lot different across inequality, productivity. Growth will look different if you're looking at the welfare contributions rather than just where we're spending money.

Paul Krugman

Okay, so you said, though, that you don't think the measurement issue is important, but that's not the key, or that there are bigger things explaining this?

Erik Brynjolfsson

Yeah, it's hard to know because nobody really did a good job of measuring the consumer surplus from, I don't know, the smallpox vaccines or whatever and things that were obviously incredibly important a long time ago. (And today.) So that comparison is a little tricky to make.

Paul Krugman

Yeah.

Erik Brynjolfsson

I spend a lot of time talking to companies and, actually going back to the 1980s and early 90s when I was a grad student, even then I would spend some time talking to senior executives. And I could see the business transformation that was going on then and now and how important that is. And in a follow up paper that Chad and Daniel and I wrote called The Productivity J Curve, we calibrated this and found sort of a J-shaped effect of this investment.

Paul Krugman

So an initial drop rather than a rise.

Erik Brynjolfsson

Exactly, because what happens is, at first you have to reskill your workforce, put a lot of time into training and people on their own have to figure things out. You build new business processes, even new products and services, new organizations. Like what we were talking about that Paul David found with the electricity. All of that is creating what I would call “an intangible asset,” but that's another thing that's not measured in our economy, a lot of these intangible assets. So you see a lot of effort but no measurable output. In other words, productivity goes down. More input, no output. Later, you start harvesting those gains. Now you're like, “Okay, we've got these things set up. Our workers are re-skilled. We've got new business processes. We've invented some new products.” And now you're harvesting that stuff. And now productivity is actually unusually high because again, you're not counting the intangibles. So at first it's down and then it's up. So it's a J-shaped curve.

Paul Krugman

That makes a lot of sense, that basically if you spend three, four years reconfiguring how you do your business, it's going to require spending a lot of effort. When we measure, we mainly count capital goods, production of capital goods as part of GDP but we don't count production of intangibles like organizational improvement as part of GDP.

Erik Brynjolfsson

That's right. And more and more of those are what's important. I was visiting Dell and, if they want to double the output of producing computers or anything, you know, they could build a second factory next to the first one. That would get counted. But if you put a lot of intangible effort into creating new business processes and re-skilling—so, get twice as much output out of the first factory—that would not be counted as an additional asset, even though from an economist perspective, it kind of has created an asset that you're getting a stream of value from.

So, we’re mismeasuring the digital goods that we're consuming, we're mismeasuring a lot of the intangible assets. And again, that adds up to trillions of dollars according to our best estimates. So, as the economy becomes more and more digital, more and more intangible, we're kind of missing more and more of what really matters.

Paul Krugman

You get all of this great stuff that seems to be happening in technology after the mid-90s that doesn't seem to be showing up in the numbers. And one answer would be that businesses are really spending a lot of effort on adapting. But then...

Stupid indicator, but if you go back and look at Dilbert cartoons from the early 1990s, the office work looks pretty much the same as it did until a couple of years ago. Was there really a lot of organizational change over that period?

Erik Brynjolfsson (23:22)

I think there was. A lot of it's under the hood, you know? Obviously the internet changed a lot, but it takes time. You know, when Amazon started doing online sales in the mid 1990s, it wasn't like the next day we all went to shop digitally. It's only just now, 25 - 30 years later that we're beginning to have digital commerce surpass traditional commerce in lots of areas, but you're also seeing the cloud infrastructure. And then most importantly, just recently, AI and agent-based systems are beginning to automate and augment a lot more of what's going on. But part of my mission is to shorten that. I've written a number of papers now to describe the kind of business process transformation that's needed, and I even started a company called WorkHelix that helps companies implement some of those changes.

Paul Krugman

So yes, you're trying to not just measure, but actually sort of make it happen.

Erik Brynjolfsson

I think so. You and I both know Bob Gordon. He's one of the greatest economists who's been studying growth and he was kind of a mentor of mine early on and helped me many times. And we agree on so many things, but one thing we disagree on is what's happening right now and in the near future to productivity growth. We made a bet. I bet that productivity growth was going to significantly exceed the Congressional Budget Office projections for the 2020’s.

He took the pessimistic side of that bet. We'll find out in a few years. But I'm trying to also, you know, actually improve my odds of winning by spending more and more time talking to managers and showing them how they can implement these technologies in ways that are more productive. And I'm pretty hopeful. Already we’re beginning to see some glimmers where companies that have installed AI have begun to have very measurable gains in call centers, software coding, sales… various internal large language models where they're beginning to see some big gains from it. As that spreads throughout the economy, I think we're going to have an upside surprise on productivity.

Paul Krugman

Obviously we hope you're right. So, let's talk about AI. I have colleagues who sort of bristle at even calling it AI and want to just say “large language models” (LLMs) or whatever. How would you describe what it is. Clearly something has changed. Clearly we have systems that do stuff that we weren't able to do before.

Erik Brynjolfsson

Yeah. Well, one of the biggest changes is the machine learning revolution. So back when I was doing AI, we called it that. I was building rule-based systems, expert systems, where I would sit down and interview experts and they'd give a bunch of if-then rules. “If someone's coughing, they might have a cold,” or something like that. We do it for banking and for other things. But you had to hand-code everything. Machine learning is different. With machine learning, you give the machine a bunch of inputs and a bunch of data on outputs. And then the machine learns. It figures out the relationship between the inputs and outputs. To make this work, you need lots and lots and lots of data. And the good news is that since the 1990s, we've digitized so much of the economy. We have a ton of data, text data in particular, but also images and other things. And we feed those into the machines, and they start finding patterns on their own. And they use neural nets, deep neural networks, these layers of neural networks that are sort of loosely inspired by the human brain. And they're beginning to really be very good, getting to human level or superhuman in more and more categories like image recognition.

And we've all played with, you know, Chat GPT and the other tools and they can write pretty decent essays. Maybe not the quality of your writing, but the quality of a lot of people's writing. And they're getting better literally month by month. And basically, under the hood, they're using these neural networks. The first wave was more trying to diagnose and pattern match, make predictions and classification. The new ones, the generative models, are actually creating new content, either text or images or even videos and other kinds of content now.

But what's different now versus before is a lot more data, like orders of magnitude more data. A lot more computing power, going beyond Moore's law and switching to GPUs like the Nvidia cells that allow them to do more faster, better processing than they could before, and some improvement in algorithms, those three things.

Paul Krugman

For viewers, Moore's Law is the—what was it?

Erik Brynjolfsson

Originally it was doubling every 18 months, then you kind of modify it doubling every two years, but it's sort of an exponential improvement in computer power that's been going on for about 50 years.

Paul Krugman

A single chip—if it doubles every two years, that's a factor of 1,000 in 20 years. It was amazingly stable.

Erik Brynjolfsson

Exactly. I mean, they call it a law but it's more like a mystery because there's no law of physics that says this has to happen. But they've just been able to keep shrinking the size of the transistors and the circuitry. And with that, you get faster and faster and more and more. It's beginning to get harder just to turn the crank on that dimension. But what they are doing is improving on other dimensions. To do large language models and other kinds of neural nets, you need to do a lot of matrix multiplication. And these GPUs happen to be very good at matrix multiplication, so they were able to piggyback on that, even though the underlying circuitry wasn't getting that much smaller. It was just a better design for these kinds of problems.

Paul Krugman

Much of this is as mysterious to me as it is to, I think, a lot of people, but I actually do know what matrix multiplication is. You have two big arrays of numbers that have to be kind of like matching sizes, and there's a process for multiplying them to produce a third array. This is something like PageRank, which is the original way that search engines were able to figure out what's important. And you're saying that a lot of this stuff basically involves some version of that.

Erik Brynjolfsson (30:04)

Yeah. A nice quirk of history was that these GPUs (Graphic Processing Units) were first used for rendering images on screens. You have to do a lot of matrix multiplication for that. And then some people like Andrew Ng figured out, wait a minute, we can use these for neural nets as well. We just change the code a little bit. And lo and behold, you were able to tap into orders of magnitude more processing power. And now they're making them special just for neural nets, but initially they were kind of repurposing them.

Paul Krugman

Okay, and so we have these redesigned chips with something like Moore's Law so data processing is still getting cheaper in general, but we also have specialized data processing in a form that is good for this. But should we be calling this intelligence? I mean, in some ways that horse has left the barn. We are calling it that.

Erik Brynjolfsson

You know, that's a good question. It's a little semantic. I don't think it's like a sharp line. So, I moved to Stanford a few years ago. I love Cambridge and MIT and all the intellectual horsepower there. But Silicon Valley is just a different world. Initially, I was in the economics group. And now I moved over to the computer science building, the Gates Building. And next to me is Chris Manning and a lot of the other giants of computer science. So I went and asked him,

“Can I call this intelligence? Can I call this understanding?” And he thinks it's okay to do that. These systems are basically answering questions the way an intelligent person would, sometimes a little better, sometimes a little worse. And I guess there's a philosophical debate about whether that's true understanding. But when it comes to solving problems and actually figuring out what the next step in this scientific process is, or understanding who committed the murder in this mystery story, or solving a little puzzle, or writing an essay that's kind of coherent about the Crimean War, they can do that. So I'm OK calling it intelligence.

Paul Krugman

Yeah, I mean, I have friends who say, this is just sort of super powered autocorrect. I'm on both sides of all of these debates, but my response to that is an awful lot of jobs—some erstwhile high skilled, high paid jobs—are basically like super powered autocorrect.

Erik Brynjolfsson

Absolutely. That's another good point. I had a talk with Demis Hassabis who came to visit Stanford a while back. He's the founder of Google DeepMind, got the Nobel Prize a few months ago, and he's been working on this basically all his life since he was a teenager. And he said that when he found out how well LLMs (Large Language Models) were working, he was actually a little disappointed because he thought matching human intelligence would take more than that. And he was like, “Maybe a lot of us, what we do is super powered auto completion, and that you can get a lot done with that.”

You know, from an economist perspective, that's kind of the point I focus on. If you want to look at how the economy is going to change, what we're doing, what exists right now is already enough to affect a big percentage, maybe half of all cognitive jobs. And what we are going to see in the next few years is going to only increase that ratio. So, we're already there in terms of having an economic revolution. I often use the term “transformative AI” just to emphasize: let's look at what's happening to business transformation, economic transformation, and leave it to philosophers and others to debate whether it's truly artificial general intelligence or something else. I don't think there's any doubt that it's economically transformative.

Paul Krugman

Okay, yeah. I mean, when did people stop saying, “Learn to code to make a living. Learn to code.” And now it turns out that that's one of the things that these models are really quite good at doing, right?

Erik Brynjolfsson

Hahaha. Yes, it turned out kind of by accident that they found that they were incredibly good at coding. The way they trained them was that they gathered all this data from the internet and the web, and they just scraped it all in there. And it turns out that there's a fair amount of code up there on the internet. And so these systems learn to complete code and understand. In order to do that effectively, you have to kind of understand the logic of code. And these neural nets were finding patterns there and were able to get very good at coding. It's one of the things they're best at. And so that's kind of a canary in the coal mine, our coding jobs.

And there's another interesting twist, which is that, what are these systems made out of? They're made out of code. So now we're getting, you know, the recursive self-improvement that people talked about in science fiction, 50 or more years ago. And that can lead to something like the singularity where you get these systems that are improving themselves, and then they're able to improve themselves at a faster and faster rate. I don't know if we'll have that kind of very rapid takeoff, but if you talk to the people in the big AI companies, they are using LLMs and coding tools a great deal now to generate a lot of the code that they use to make the next generation of large language models.

Paul Krugman

Oh boy. And then it kills all of us. No, I mean, there's a cynical side which says that the LLMs do have a tendency to fantasize a little bit. But give me your take on it.

Erik Brynjolfsson

Yeah, they hallucinate.

Paul Krugman

Search these programs for yourself and you discover that there are all these interesting papers attributed to me that neither I nor anybody else wrote. And there's the choking on its own garbage scenario, where as more and more of the data out there is generated by these models, it starts to just descend into a loop of self-replicating garbage.

Erik Brynjolfsson

Right. If most of the content on the web starts being generated by systems, can they learn from themselves? This is kind of a little bit above my pay grade but I talk to the people creating these systems, many of them are actually surprisingly optimistic that you can use synthetic data to train the models, that you can create additional chess games, additional Go games, and even additional essays. And coding actually is one that you can do and use to train models to get even better. You can have it write puzzles and then solve the puzzles and it improves itself. So they are making some progress now. We'll have to see how far you can go with synthetic data, but that could be a possible way of extending the runway as we're close to basically having fed all of the data on the World Wide Web into these models. So you need to have some other source of data or improvement. And that's what they're working on. Synthetic data.

Paul Krugman

Okay. Although it's all digital and it's just bytes, it turns out there's an awful lot of BTUs that are going into this. The energy consumption has turned out to be kind of alarmingly high. Is there a way past that?

Erik Brynjolfsson

Yeah. I think it's legitimate to be concerned about that. So one of the simplest ways to make these systems better—simple but not easy, I guess—is you just make them bigger. And every time you make them bigger, there's like a predictable improvement. People call these scaling laws. And so one of the reasons these companies are asking to build bigger and bigger data centers (OpenAI said they want to build something called Stargate that's $500 billion worth of data centers) is that, according to the scaling laws, if you just make them that much bigger, you're going to get that much better.

But of course, giant data centers require giant amounts of electricity. So they are re-starting up nuclear plants. Three Mile Island is getting started up again. They're building new small nuclear reactors. They're trying to get more and more solar. They're firing up coal and oil plants that otherwise they probably wouldn't have. So that has negative effects on the environment. Some people like Eric Schmidt have said, “Well, look. Yes, that's costly. But if we want to solve our environmental challenges, we need more intelligence. In the long run, it's going to be better to have this additional intelligence to come up with better solar panels and better processes for all of our industrial processes. And ultimately, the way to address that is to have more intelligence.”

The other thing, especially since DeepSeek, the Chinese model, came out a few months ago, is people are understanding that you can actually get an incredible amount of power from much, much smaller models, an incredible amount of intelligence.

And so that's a margin that more people are focusing on: can we use better algorithms to get more intelligence instead of just turning the crank and making them bigger and bigger? I don't know for sure how that's going to turn out. I don’t think anybody does. They're working on both dimensions and many other dimensions, really like six different dimensions where you can improve these models. So I think we all hope that we'll be able to get more intelligence without using lots more electricity.

Paul Krugman (39:58)

Okay. DeepSeek is sort of third hand, but doesn't use all the data in the world.

Erik Brynjolfsson

Yes. It's much, much smaller or is of a magnitude smaller. And interestingly, you know, it was not like one big breakthrough or “a ha.” It was a lot of small engineering tweaks. They got 3% improvement by doing this and 8% by that and 1% by that. Nvidia, who we mentioned earlier, has a whole stack of CUDA, this software that runs on Nvidia chips that most people use. They kind of bypassed all of that infrastructure and went down to the machine code level, which is

much harder. It’s much more painful to do that kind of coding. But if you do it, you can get huge efficiency gains. So this is the kind of hard work that they did to crank out more efficiency. And, now everybody sees that there's an opportunity to have AI systems that are much, much smaller, use much less electricity and still perform basically just as well.

Paul Krugman

That would be a huge relief if we managed to do that because the energy burden is kind of scary right now.

Erik Brynjolfsson

Yeah. Well, as an economist, I don't know the answer, but we're trying to think about what's the marginal value of intelligence? If we push the frontier of having a bigger model and get a few more IQ points or the equivalent, how valuable is that? Maybe the average store owner doesn't need, like, Einstein to come in and rearrange their shelves, but they need a pretty smart system to do that. And when I think about what's going on in the economy, I think not every business could benefit from having a bunch of Einsteins get off the bus and start telling them what they could do. But they could use a lot of sort of like reasonably smart people to help them out. Maybe over time that will change. There's also the elasticity of intelligence, that as people realize that really high levels of intelligence are available at very low cost, they'll reorganize in ways that take advantage of that.

We're in for some interesting times in the next few years as the price of intelligence falls dramatically.

Paul Krugman

I was about to say, as economists, we don't know anything about business, but you actually kind of got a foot in that world as well. Still, one big question we have here is, obviously, we've got something that is really, really impressive and novel and has startled a lot of people with how well it works. There are corporate valuations that are kind of based on how amazing the technology is. And one thing I thought we learned from the internet boom was that amazing technology doesn't necessarily mean amazing profits.

Erik Brynjolfsson

That's right. Well, let me underscore both parts of that. I do think that these technologies are really amazing and transformative, and they're probably going to create trillions of dollars worth of value. But much of that value, if we have a well-functioning market, will end up in the hands of consumers, not producers. Bill Nordhaus estimated that about 95% of the gains from innovations ultimately go to consumers, not to the people who create it. So there's no guarantee that any of these guys who invent the best new system are going to be able to cash in on it fully.

I think the internet's not a terrible analogy. You know, we saw lots of gains from that. But there was Pets.com which was a total joke, and there was Amazon that did pretty well, and there are lots of companies in between. I think this wave is going to be significantly bigger, both in terms of the consumer benefits and also in terms of the winners and losers. And lots of smart people are making bets that they're the company that's going to win. I think if you really do believe that the technology is as transformative as I do and as a lot of other people do, it's not implausible that some of these companies could be worth a trillion dollars or more, but probably not all of them. So, how to figure out which ones are on the winning side and which ones aren't? Well, we'll leave it to the market and others to sort that out over the next few years.

Paul Krugman

Yeah, I mean, back during the internet boom, the dot com and all of that, we used to say that investors seem to be betting on 10 or 15 different companies, that each one of them was going to be the next Microsoft and acquire this sort of spot, and they couldn't all do it.

Erik Brynjolfsson

Yeah. They couldn't all do it. At the same time, I do remember sitting around in the faculty lounge. I was visiting Stanford Business School, and Amazon was this little company competing with Barnes and Noble. Some of my faculty colleagues were saying, obviously, Barnes and Noble is going to crush Amazon now that they see that this is available and I was debating that. Sometimes the new companies do figure out how to capture all of the market. And then, it wasn't just books. Obviously, Amazon captured a lot more than that.

So yeah, we're at a similar stage right now. Even as we're speaking, the stock market is crashing for a lot of the—well, I wouldn't say crashing, but going down quite a bit for some of the companies that had the biggest bubble valuations a few months ago.

Paul Krugman

People were saying in the 90s that each company was going to be the next Microsoft, but then a lot of the companies that have gotten these huge valuations already are. They already have dominant market positions. So in some sense, it is almost like defensive investment. They're safeguarding their position, which doesn't seem to say that the valuation should go up.

Erik Brynjolfsson

Yeah, well, the folks at Microsoft have told me, and I don't think I'm disclosing anything that proprietary but, you know, if AI turns out to be everything it's cracked up to be, they'll be very happy they made the investment. If it turns out not to, maybe they're going to lose tens of billions of dollars. But that's something that they could afford if they had to. But they can't afford to be scooped. So when they look at the two sides of it, they feel like they need to be ready to make this investment.

Paul Krugman

Right. But that's an argument for them doing the right thing, not an argument that people bidding up the price of their stock are doing the right thing. Actually, with Nvidia, they've really emerged as a major player in a way that they weren’t before.

Erik Brynjolfsson

Yeah, Nvidia provides the chips, the GPUs that power most of these systems. And people build on top of those. And CUDA, the software that powers them, is what most people are using. And they continue to have a lead in that. People are trying to come up with other architectures that can work around that. Google has their own chips. They call them TPUs, Tensor Processing Units. But right now, Nvidia is benefiting from everybody trying to get a hold of those chips so that they can build bigger and bigger and better and better systems.

Paul Krugman

Yeah, the people who made money in the California gold rush weren't the gold miners, they were the people selling picks and shovels and blue jeans to the gold miners. And Nvidia is kind of in that position.

Erik Brynjolfsson

Yeah, that's where Nvidia is. And at some point, all that money that's being paid to Nvidia has to come from somewhere. And so the companies that are making those investments are betting that consumers and customers will be paying some multiple of that to them in order to justify the investments that they're making.

Paul Krugman

So how are you feeling about your bet with Bob Gordon?

Erik Brynjolfsson

I'm feeling pretty good. I'd say right now we're close to even. Maybe I'm a little bit ahead. But I've always thought this is sort of the second half of the decade thing. So I'm glad we survived the pandemic and everything else in terms of being remarkably stable. We're more or less at the pre-trend or even a little bit above the pre-trend prediction for productivity. So the past few years, we've navigated it pretty well when it comes to some major disruptions. And now what I see when I visit companies is that they roll out these systems for coding we were talking about, for call centers, for lots of other things, and they're getting 20, 30, 50% productivity gains in those particular applications. As that fuses through the economy, we're going to see an extra few tenths of a percent or half a percent or even a full percent of productivity growth. And that's more than enough to get me to win that bet.

Paul Krugman

It’s been hard with the pandemic and all of the stuff that followed. There's an awful lot of noise and dust in the air.

Erik Brynjolfsson

Just looking at the technology side of it, you know, there's a lot of other things. There's a lot of geopolitics, there's some bizarre macroeconomic things going on, and all of that, of course, could throw a wrench into things. But if you just look at the base prediction, I'm pretty optimistic about productivity and growth.

Paul Krugman

In the mid-90s, there were a lot of people out there who were sort of looking around and saying, “We think that we're going to have this productivity boom out of IT, and we already see it happening.” And I looked at the hard data and said, “I don't see it. I'm really skeptical.” I was totally wrong. History leads me to think that you're probably right. I certainly hope that you are.

Erik Brynjolfsson

Yeah, I'm more optimistic this time. Back then, you know, after I wrote that paper, the “Productivity Paradox of IT,” and then I gathered some data from 500 companies about what was happening, I saw some gains and I wrote a paper called “Paradox Lost” that basically showed that it was beginning to turn around. That was in 1995. And sure enough, even as that has spread, I think AI is bigger than any of the technologies we've seen before. As Andy McAfee and I wrote about in The Second Machine Age, you know, now we're not just augmenting our muscles, but our brains. And that's a really big event in history. I was going to say “human history,” but just history in general, to be able to do that.

Paul Krugman

We're almost obsolete already.

Erik Brynjolfsson

Well, for certain things. And so then I think we have a real challenge that economists need to get at, and that's what my focus is these days: how do we reinvent the economy for a world where machines can do not only most of the physical labor, but more and more of the cognitive work, and how do we figure out a system for not just having prosperity, but for having shared prosperity? Most people get most of their income from labor right now, and if machines are able to do more and more of that, we're going to have to think about other ways of distributing the benefits in ways that are widely shared. I think the default will be that benefits get more and more concentrated and both wealth and power get in the hands of fewer and fewer people. And if we don't want that to happen, we have to be proactive about kind of reinventing our system and our economy in a way that we have the benefits widely shared.

Paul Krugman

I think that's probably a good place to stop. Let's hope that the kind of wisdom that you're hoping for actually materializes. I'll take that bet. I'll take the under on that.

Erik Brynjolfsson

Okay, well we'll do what we can.

Hopefully it's not just a matter of watching it happen but working to make the good outcome happen. And thanks for giving me the chance to chat with you and I hope your listeners and all of us work towards that better future.

Paul Krugman

Thanks, this has been fun.

Erik Brynjolfsson

My pleasure.

COVID Metrics
	Now	Week Ago	Goal
Deaths per Week	635	692	≤350¹
¹my goals to stop weekly posts. 🚩 Increasing number weekly for Deaths. ✅ Goal met.

This is the fourth part of our [five? -ish? I, II, III] part series on the Siege of Eregion in Amazon’s Rings of Power. Last week, we took the opportunity presented by Adar’s absurd plan to dam a river using catapults to collapse a mountain to discuss the capabilities and functioning principles of historical counterweight trebuchets, the largest and most powerful sort of catapult. While trebuchets were powerful weapons in their day, Rings of Power, like many modern films and TV shows, presents the weapons as having orders of magnitude more range and power than they did historically, showing them used to do things that the actual weapons simply couldn’t accomplish, like rapidly demolishing a city or collapsing cliff made of solid rock in moments.

This week, with the Sirannon river protecting Eregion’s capital, Ost-in-Edhil, is now drained, the orcs begin their assault, giving us an opportunity to discuss what a more competent prepared fortress assault might look like. Now I want to note this sequence gets complicated quickly due to the appearance of relief armies, but we’re going to break this up thematically, treating the attack on the city in this post and the fighting with the relief armies in the next post. Fortunately, because Rings of Power is broadly incapable of managing cause-and-effect, the fact that not one but two entire relief armies show up unexpectedly matters not at all in the battle or to any of the important characters, which makes this sort of division of topics easier (even as it makes the show worse).

Book Note: We can essentially do just one book note for this entire sequence. We are given no details in either the appendices or Unfinished Tales on how the capture of Ost-in-Edhil was accomplished, except that it clearly fell by assault (rather than surrender) and the effort took some time: the attackers break in “at last…with ruin and devastation” and Celebrimbor is taken while fighting with Sauron himself “on the steps of the great door of the Mírdain” (Tales, 228). But that skeleton of a description nevertheless leaves room – indeed, clearly seems to actively imply the kind of slow, methodical and careful assault that is more commonly successful historically. I suspect here this is in part because Tolkien is echoing the way that historical texts, both ancient and medieval, relate the outcomes of sieges when they aren’t going to give a detailed, blow-by-blow description: there’s often an indication if the siege was long or short, if it was difficult or easy (not always the same as length) and then frequently just one or two vignettes such as the last stand of a significant figure or a notable moment of treachery or so on. Here what Tolkien gives us tells us the siege was long, difficult and ruined the city and then gives us in just a few words the vignette of Celebrimbor’s final, doomed resistance protecting the thing he cared for most, the “their smithies and their treasures” (Tales, 228), rather than, you know, the people. It is telling that this is where Celebrimbor’s final defense is held, one last statement on his character, not wholly negative but also not wholly positive either – no Ecthelion of the Fountain or Glorfindel of Gondolin is Celebrimbor.

But first, as always, sieges are also expensive! If you want to help out with the logistics of this blog and my scholarship more broadly, you can support me and this project on Patreon! I promise to use your donations to carefully construct mantlets and moveable shelters to protect my soldiers as they advance, slowly and methodically towards the walls of the enemy, rather than being picked apart by arrows. If you, like Eregion, completely lack scouts or information gathering of any kind and are thus regularly surprised when posts like this appear outside of your walls, ready to sack your ~~homes~~ free time, you can get a bit more warning by clicking below for email updates or following me on Twitter and Bluesky and (less frequently) Mastodon (@bretdevereaux@historians.social) for updates when posts go live and my general musings; I have largely shifted over to Bluesky (I maintain some de minimis presence on Twitter), given that it has become a much better place for historical discussion than Twitter.

Swarming Like Ants

With the river now drained, Adar’s next step is to launch his orcs across the riverbed in a disorganized rush against Ost-in-Edhil’s defenses. This sort of assault is extremely foolish for a number of reasons. The immediate reason is a problem of terrain: Adar has given the river time to drain but not to dry, meaning his soldiers are likely attacking across a damp natural riverbed. When we see it, we see a bed that looks to have consisted mostly of silt and sand, which is to say, quite fine particles which are, in this case, still wet. I imagine just about anyone who has ever waded across a shallow river understands the difficulties Adar’s troops – weighed down by equipment, armored and in some cases pushing siege equipment – will almost instantly be in. This terrain is going to be difficult: wet and muddy, soldiers will sink in it, where it isn’t slick and hard to maintain balance. This is potentially the sort of muddy, viscous terrain that armies in the First World War used duckboards to cross.

Adar is attempting to charge over it.

I keep having to ramp up the brightness on these screen-captures, but here you can see particularly in the distance the challenge of this terrain: these men are charging down into what is essentially a massive muddy pit.
Good Luck. With. That.

The second reason this assault is extremely foolish is actually a very old one. Adar’s draining the river hasn’t removed Eregion’s defenses, the city is still walled along the riverbed (and Adar, for whatever reason, hasn’t considered now looping around those defenses but attacks straight into them). So Adar’s implausible catapult-terraforming has merely given him the opportunity to engage in a traditional fortress assault over unusually difficult terrain – he hasn’t actually prepared at all to assault the walls themselves. His catapult barrage, as noted above, didn’t damage the defenses in any way, they were focused inside the city on fragile but militarily unimportant buildings. Adar is then hurling his army, with no real order to it, against those walls.

Indeed, this sort of attack is such a terrible idea – and such a famously terrible idea – that it is not infrequently held out as the example of a terrible idea in military treatises. Here, for instance, is a famous passage of Sun Tzu’s Art of War, describing the perils of sieges (trans. Lionel Giles):

4. The rule is, not to besiege walled cities if it can possibly be avoided. The preparation of mantlets, movable shelters, and various implements of war, will take up three whole months; and the piling up of mounds over against the walls will take three months more.

5. The general, unable to control his irritation, will launch his men to the assault like swarming ants, with the result that one-third of his men are slain, while the town still remains untaken. Such are the disastrous effects of a siege.

Adar has not even ascended to the basic level of competence of Sun Tzu’s idiot-general-making-obvious-mistakes in this passage, because he hasn’t yet spent several months building mantlets¹ (we’ll come to these) or piling up other works and has instead after just one day launched straight to the “assault like swarming ants” part of the battle. And note the result Sun Tzu expects from this approach with better preparation than Adar‘s: “one-third of his men are slain, while the town still remains untaken.” Poorly prepared, badly thought out siege assaults generally fail; the entire reason for the complex systems of siege engineering and large, expensive siege machines was precisely that one could not simply win a fortress assault by rushing at the wall en masse.

This is the ram they’re going to use, but I want you to focus on the terrain they’re moving through: completely saturated mud with pools of standing water. I see they have duckboards for the big machine, but this would be hard ground to **walk** through and I have a hard time imagining those puny sticks handling the weight of a large siege engine either.

And here we run back into the storytelling failures of this part of Rings of Power. In the Lord of the Rings, we have two sieges: a competently executed prepared assault and an incompetently executed hasty assault. Now, both end up failing because of heroic intervention (while the storywriters for Rings of Power need this assault to succeed), but what I want to draw attention to is how the way these sieges proceed illustrates character. Saruman’s attack on Helm’s Deep is, as I’ve noted, poorly managed. His army isn’t very cohesive and is unprepared for things they ought to have seen coming. Moreover they’re also unprepared to effectively assault this fortress, having banked everything on a sapping effort with blasting fire that doesn’t expose the main citadel. As a result, the effort fails due to Saruman’s bad planning: his overconfidence and lack of field-specific knowledge show up very clearly in the way his efforts fail, resulting in him being defeated by an inferior force.

The Witch King’s attack on Minas Tirith, by contrast, is very capable executed. The Witch King has prepared specific engines, like Grond, to engage specific parts of the defenses. He has left blocking forces (the Corsairs and a wing of his army in Anorien) to isolate the battle-space. He has reserves to guard against potential problems. And his assault, while necessarily swift is methodical: trenches to protect his equipment, then catapults to start fires in the lower levels to isolate the outer defenses (something Adar’s catapults do not accomplish), then towers to engage the defenders at all points, so that there is insufficient force at the decisive point (the gate) when his main effort arrives with Grond. As a result, it takes the combined efforts of several very capable commanders to stop him: Denethor, while he retains his wits, employs a masterful defense in depth, Faramir’s ability as a captain to hold his men together is remarkable, Théoden shows excellent generalship in side-stepping the blocking force to deliver his cavalry to the battle.

And yet in all of that we learn something about both the strength of the Witch King, but also his cunning and malice, because despite such capable opponents, his plan mostly grinds on as intended: the defenders are driven in, the defenses isolated, Théoden’s cavalry engaged and put into desperate straits against his reserves. We see both the Witch King’s character strengths – cunning, intelligent, methodical and deliberate – and of course his flaws as well in that it is his arrogance that leads to his death even at a moment when his plan is probably still more or less working (Aragorn not having arrived yet).

In short in both cases the way the siege proceeds is both connected logically to the material conditions of the siege – that is, it makes basic physical sense – but it also proceeds out of the character of the characters who are conducting it. The Witch King’s ruthless disregard for life is on display in his method of attack, as is his arrogance in advancing through the gate first, so confident in his victory, as is his cunning in the fact that he had a ‘Minas Tirith Main Gate Buster’ specifically prepared and ready to go for this very moment. Equally, Gandalf, Faramir, Théoden and Aragorn’s quality all emerge when pitted against such a capable foe.

The siege set piece becomes more than just a tool for special effects, it becomes a mechanism to develop characters. We learn a bit more about who these people are by the way they behave in these circumstances and then the consequences those behaviors have in terms of winning or losing the battle.

But in Rings of Power, Adar is a complete idiotic fool whose plans are terrible and go wrong repeatedly who nevertheless wins easily anyway for no clear reason. Adar has laid a siege on a city with insufficient preparation, charging his army blindly across a mud-soaked riverbed into prepared defenses without any preparation before being suddenly and unexpectedly attacked in the rear twice and wins anyway. I think we are supposed to learn from this that Adar disregards the lives of his ‘children’ in his monomaniacal pursuit of Sauron, but what we actually end up learning is that battles in Rings of Power are like rounds of Whose Line Is It Anyway: the rules are made up and the casualties don’t matter.

We don’t even learn what kind of person Adar is – beyond his willingness to spend the lives of his orcs (although we don’t see very much of this either) – in the way he attacks. Is Adar a great tinkerer and engineer, so that he would, like Saruman attack with a new technology (blasting charges)? Is he methodical and deliberate like the Witch King, dismantling one defense after another in a series of careful attacks, long in deep preparation? We get none of this. Adar doesn’t have catapults because he’s shown to have prepared them for years or really like siege engineering, he has catapults because…Hollywood sieges have catapults. His stunt to drain the river doesn’t seem to come from some established deep knowledge or interest in hydrology (though this would have been a clever thing to set up, given the equally silly role of flooding waters in Season 1 – but Adar has no hand in preparing that!) or geography.

We learn nothing about Adar, who remains a very flat character, a ‘Lord Father’ who doesn’t care much about his children and is obsessed with his war against Sauron. He doesn’t seem to believe in much, or be interested in much, or have much personality. Like Bronwyn, like Arondir, like Waldreg, like Mirdania (I had to look up some of these names) and like so many others, they kill him at some point and I felt nothing.

Making Works Work For Your Work

What ought Adar be doing? He should be doing quite a lot of work, actually – building quite a lot of works. ‘Works’ in a military context (particularly a historical one) is the word for basically any constructed element of a battlefield, particularly field fortifications. Because there’s actually quite a bit Adar can do in order to make his assault on the city more likely to succeed.

As we’ve already noted, this task would probably begin with circumvallation: building a line of defenses around the city, parallel to its walls (or around the bridges and gates, in this case) to prevent the enemy from advancing out. This matters to Adar both because it means the enemy can’t dash out and smash his catapults and other preparations, but it also means his high value target probably can’t escape.

Book Note: The Witch King does exactly this in the Siege of Gondor, using a series of trenches (filled with some sort of flaming, perhaps magical, obstruction) to circumvallate the city and prevent the defenders from easily sallying out, while protecting the catapults and other siege engines being prepared (Rotk, 105). These works are abandoned when the Rohirrim attack, enabling the men of Gondor to sally out to support the Rohirrim’s attack as it develops, but seemingly only around the gate (where presumably there were gaps in the works to allow Grond to approach the gate).

Those defenses in turn provide the foundation from which other works can be assembled. The first task, of course, would likely be assembling the catapults, which will have been transported to Eregion unassembled in carts and need to be set up on site. Now those catapults, as we noted last time, are not going to be deployed miles away, but probably fairly close to the walls – as close as they may be safely placed, since the closer they are, the harder they’ll hit. That in turn means the catapult firing positions may also require defenses beyond the initial circumvallation. You do see this sort of thing in medieval warfare, but I will note that protected artillery firing positions becomes really important in early gunpowder warfare, where siege artillery often had to be set within a few hundred yards of a wall to have the desired effect (well within musket or counter-battery artillery range). We’ll get to what those catapults should be doing in just a moment, but once set up, they’d start doing it while the other elements of the attack are prepared.

The next problem, of course, is the river. Simply damming the river – as we see in the show – is impractical…as we see in the show (and discussed last week). But armies could sometimes divert rivers and I’d expect any real siege of a place like this – given how hard approaching the city from any direction other than the river – might have to do this. Diverting the Sirannon would be a matter of digging a canal around the back of Adar’s besieging army (conveniently serving as a degree of contravallation) and his workers would be protected from the enemy by his circumvallation as they did so. Alternately, Adar might try to build new crossings over the river, depending on its depth and speed. Because the Elves lack any kind of artillery of their own, there isn’t really anything to stop Adar’s orcs from building pontoon bridges, perhaps braced with earth and rock fill, to crudely span the river at multiple points in order to enable assault (in addition to the existing primary bridge we see).

Now of course both when building any works over the river or crossing its dried river bed, orc workers and soldiers would be exquisitely vulnerable to the defender’s arrow fire. The solution to that is the venerable mantelet (sometimes spelled mantlet), relatively small portable shields or shelters that could be moved forward as necessary. In medieval sieges, its common to see networks of these wooden barriers, providing covered attack channels to approach walls and protecting stations of archers or siege workers from attack from the wall. Large siege engines – like rams – might have full, wheeled housing covering them to prevent the operators from being engaged from the walls. The advantage on a medieval battlefield that the attackers have is that the projectiles available to the defenders (arrows, slingshot, javelins, etc.) are light enough that a relatively thin wood or even wicker framework is enough to ‘catch’ them and render them harmless. In the gunpowder era, these sorts of field defenses have to get more robust and heavier – earth-filled gabions, the ancestors of today’s HESCO barriers – and thus immobile, requiring armies to effectively ‘dig forward’ to reach a wall, in a system we’ve already described elsewhere. Because mantlets are cheap, fairly quick to make and use a locally available material (wood), an attacking army can produce a lot of them and indeed, we tend to see these used in quantity.

From the British Library’s Catalogue of Illuminated Manuscripts, Royal 14 E IV (alas, not yet restored online after the 2023 cyber attack as of March, 2025), a siege scene; the manuscript, written in French and probably produced in Flanders, dates 1470-1480.
You can see the use of mantlets to protect archers and artillery very clearly on the left.

Of course the jumbo-version of this approach is a ‘siege tower’ – generally called a ‘belfry’ by our medieval sources. These were large wooden towers – sometimes, but not always wheeled or otherwise moveable – constructed by an attacker. In film and fiction, these invariably have boarding bridges on the top and are used to assault walls, but that was actually a far less frequent way to use them. Instead, the normal use of siege towers was to create elevated, protected firing positions and to thus screen the advance of soldiers on the ground. Archers (or small catapults) elevated on the tops of these towers could sweep the fighting positions of the defender’s walls and towers from above, clearing defenders from the wall and thus neutralizing enemy ranged fire, allowing for a safe approach to the wall. In the case of Ost-in-Edhil, the presence of the river is going to mean that – either crossing bridges or crossing the riverbed – these towers are going to require some extra engineering, using wood boards and other constructions to create a flat, stable surface for them to move over. But that’s not a wild thing to do: we see Neo-Assyrian artwork from the early iron age already showing ramps and other constructions used to provide towers with easier routes to overawe enemy defenses.

In any case, Adar does exactly none of this. Not only do his orcs not have any siege towers to try to suppress the defenders or mantlets to protect their advance, they don’t even carry shields, meaning that every single orc is presenting a full body target to a city full of Elven archers. At least the Uruk-Hai at Helm’s Deep brought shields (in both film and book, TT 162-3)! We need, at some point, to return to the question of the lethality of arrow volleys against armored foes (particularly the Hollywood trope of huge casualties from mass volleys of arrows) but this is actually a force of unshielded, unprotected and relatively light infantry (we see bits of fur, a lot of leather, some scattered mail in their armor, but nothing uniformly heavy enough to resist war bow shot at medium or close range) attempting to cross rough terrain into archers who are on fortifications.

In short, this is an assault that would fail. Absent any kind of protection, these guys would begin taking losses quite quickly while – for reasons we’ll get to in a moment – the work of actually attacking is going to require them being within bowshot for quite a while as they work on overcoming the city walls. And while in real battlefields there is a lot that is greatly reducing the lethality of arrows – accuracy, shields, armor, distance and so on – such that only a small percentage of arrows are lethal, these orcs are charging Elven archers in the open, being hit by direct (rather than high arcing) fire, while unarmored, unshielded and unprotected, so we might expect most arrows to find a mark. And a good archer can put an arrow in the air around once every six seconds or so, so those casualties would accumulate very quickly. There is a reason no one attacks like this.

As we’ve seen in the book trilogy, orcs are not possessed of superhuman morale or cohesion – indeed, sometimes rather the opposite – and it would be extremely hard to get human infantry to maintain contact under these circumstances. Raw numbers here may not help the orcs much: it doesn’t actually take very high casualties to break the cohesion of most units; note about Sun Tzu describing an assault ‘like swarming ants’ which nevertheless fails, accomplishing nothing, despite its presumably tremendous numbers (in practice, such careless assaults are rare in warfare because they’re so obviously foolish to anyone not making a prestige TV show). And with no fortified, protected intermediate positions – because, again, no circumvallation or mantlets – once they started falling back, they’d fall pretty far back, at least all of the way out of bowshot.

Of course, this is Rings of Power, so Adar’s lack of preparation or planning doesn’t matter and instead his orcs simply push through by dint of numbers, which now brings us back to the orcs, their archers and catapults and the strange sort of ram they bring.

Orcish Machines

Nevertheless, Adar’s orcs now approach the wall, moving across a silty, muddy riverbed that still has pockets of standing water in it – I cannot stress how terrible a sort of terrain this would be to try to move an army over – and begins attacking the walls. To overcome the walls, the orcs have a small number of their own archers, catapults (that they don’t use), some ladders, and a machine that gets called a ‘ravager’ (as if that is a standard kind of siege engine) which makes no sense.

And when I say they **charge**, I do mean they **charge**. There’s no point to **charging** at a walled city – it isn’t going to get scared and run away. Far better to advance carefully with shields and other defenses than to rush into a bog and arrive at the walls exhausted.

No part of this assault package is deployed effectively or makes sense.

We can begin with the archers. Now, employing your own archers (or slingers or other missile troops or even small bolt-throwing torsion catapults) to try to fire back at defenders on a wall was a standard sort of thing one did in sieges, in an effort to suppress the defenders and thus enable the rest of the army to accomplish whatever it was trying to do within bowshot. But absent any protection, archers on the ground were at a huge disadvantage to archers on the walls.

Now, the orcs here have one advantage which is that – as is common in fantasy film – the Elves have designed their wall badly. It protects the archers really only up to the waist. Instead, in practice walls were – from quite deep in antiquity – built with crenelation: alternating merlons, the raised part, with crenels (the space between the merlons) to create that classic tooth-like or zig-zag pattern you see on castle walls. In film, these merlons are often quite low, but actual merlons are generally quite high, significantly taller than a man and often feature firing slits carved in them. An archer behind a merlon is thus quite fully protected. Even when standing in front of the crenel, the archer provides a really hard target, because the parapet of the wall protects him up to the waist and the effect of the height of his position makes it quite difficult for an archer on the ground to actually hit the exposed upper-part of a man on the walls.

Elven parapets, badly designed (the machine they are calling to stop is the idiotic ‘Ravager’ discussed below – it should have been pretty easy to stop, actually, it is entirely unprotected). As an aside, the fact that the Elven defenses are also pretty bog standard Hollywood fare was also a missed opportunity. Surely the city of Celebrimbor should have some advanced, technically sophisticated and remarkably well-crafted defenses, befitting his character! Instead, this place is far less well defended than Helm’s Deep or Minas Tirith, both fading relics of their society’s glory days long past.

Meanwhile the archer on the ground is really vulnerable: the height of the walls means that the defenders are firing down, which is both going to modestly increase the lethality of their shots as their arrows accelerate downward, but also enable them to fire over shields and other protections. Of course the famous Roman solution to this was the testudo, the moving box of shields, held overhead as well as in front, but our orcs here have no shields so that option is unavailable to them. Attackers might try to even these fearsome odds through the use of mantlets to create protected firing positions of their own or siege towers to create elevated and protected firing positions, but our orcs have brought neither, so their archers are sitting ducks out in the open firing back at Elves they can barely see, much less hit.

One solution to this for the attacker is to remove the crenelation and this was actually one of the quite valuable tasks to which catapults could be put. Even if the main body of the wall was too thick and strong to be breached by catapult, the parapet (the entire raised structure above the wall) and its merlons have to be much thinner and more fragile, relatively easily smashed apart by catapult rounds impacting. That might kill defenders, but more importantly it removes the cover they would use, allowing the attacker’s archers – again, all the better if operating from a siege tower – to sweep the walls. Even if they cannot breach the walls, this is what Adar’s catapults should be doing. Rather than lighting some apparently purely cosmetic fires in the city or landscaping a local mountain, he ought to be aiming to strip away the towers and crenelation of a key section of the wall so that when he attacks, it will be much harder to defend.

Of course, he doesn’t do this and so his orcs are attacking against large numbers of Elven expert archers who are basically untouchable behind a protected parapet (however badly designed) while advancing unprotected and almost unarmored in the open without shields over bad terrain, but because this is Rings of Power, nothing matters and his forces succeed anyway.

In contrast, a siege scene via Wikipedia, from the Lachish Reliefs, depicting the Siege of Lachish (701 BC) – please note how **early** that date is. These techniques were **old** when the Middle Ages were young.
If you look closely, you can see the attack involves moving siege towers up earthwork ramps topped with smooth wooden pathways, while supported by archers on the ground who are protected by larger wickerwork shields or mantlets or deployed in supporting towers.
The (Neo-)Assyrians were **really** good at siege warfare and this relief was about communicating that fact to the viewer.

All of which doesn’t matter unless he can either get over top of the walls (escalade) or through them (breach). Catapults might accomplish a breach, given enough time, but it was also absolutely possible to build walls thick and stout enough that almost no amount of catapult bombardment, even from large trebuchets, was going to produce a breach. It’s hard for me to get a good sense of if the walls of Ost-in-Edhil are this thick above the waterline, but given that Adar doesn’t even try, I am going to assume they are. They would certainly be stout enough below the waterline, since the walls would have to be quite well countersunk (that is, the wall structure continues below the surface of the ground) well below the riverbed (or they’d fall over) and either able to resist the pressure of the water (if the ground-level of the city was lower than the top of the water) or be backed by earth-fill (if the ground-level of the city was higher than the riverbed).

Adar does bring ladders to try to scale the walls. This would actually be quite tricky in practice: scaling ladders need to be the correct height. Too low and the soldiers climbing them can’t reach the battlements; too high and the ladder is in the way, making it difficult to climb off and over the parapet. That would be a particular challenge here because of the river: before the river is drained, Adar has basically no way to really know how much length to add to the ladders to account for the depth of the riverbed. But even if the ladders are correct in height, as we’ve noted before, ladders are a pretty poor way to attack a well-defended wall and pure ladder-escalade is basically always going to fail if there are significant numbers of defenders at the point of contact (as here). I assume the idea here is that the ladders occupy the defenders, but it takes a truly trivial number of defenders to defeat ladder escalade, since one man with a spear standing at the top of the ladder can defeat a functionally infinite number of men trying to climb the ladder (especially given that they lack shields or a way to damage the crenelation and thus drive the defenders away from the point of contact).

That leaves the entire attack hinging on Adar’s ‘ravager,’ which joins the Númenórean Cavalry Chain in the Roll of Infamy for bad attempts at being ‘clever’ and inventing new weapons.

A side view of the ‘Ravager.’ Also, ‘Ravager’ is a dumb name for this weapon: it doesn’t really ravage anything, it’s just a poorly designed mining tool.
Note that the machine is entirely unprotected, so any archer on the wall (for instance, one standing where the camera was) could in moments pick off basically every member of the crew – most importantly the two guys cranking the machine, without whom it cannot function at all.
Battering rams were generally **covered** for this **very obvious** reason.

The idea here seems to be some sort of reverse battering ram. The machine is brought up to the wall and big metal spikes attached to chains are hammered into the wall by orcs with large sledge-hammers (standing unproducted, in the open, while they do this, so a single archer could also easily stop the operation of the machine on his own). Then an orc (just two that we see!) manually cranks the machine, which looks to be a torsion system (energy stored in a twisted spring or rope) which when released hurls back a large wooden weight which violently pulls the metal spikes out of the wall, bringing some amount of masonry with them.

This is not a device that existed and I am honestly flummoxed as to why, if you had a device of this sort, you would use it this way. After all, if you have a torsion mechanism like this, instead of using it to pull chains there’s no reason you couldn’t instead use it to throw rocks (or swing a battering ram, but that you can do by hand), which would still work to shatter the masonry and do it quite a bit quicker. We do sometimes hear about siege grapples or hooks – the Roman falx muralis (‘wall hook’) used to pull down fortifications (Polyb. 21.27.3; Livy 38.5; Caes. BG 3.14.5) though it hardly seems to have been common and these tools – hooks on the end of poles – were worked by hand. I have to imagine they were probably used primarily against lighter elements of fortifications, like wooden fighting positions atop stone foundations (a common enough thing to do: it’s part of normal form of the Gallic fortification style the murum Gallicus (‘Gallic wall’) in antiquity and in the Middle Ages was a standard component of castle design, called a ‘hoarding.’). But the whole reason these things are on long poles is that they’re reaching at the lighter, upper parts of the defensive works, not the heavy, fixed foundation.

The metal spikes with chains being hammered and secured into the wall. If you could get this close there is no reason you couldn’t simply do this faster with pickaxes. I’d expect these spikes, most of the time, to just pull out and leave a fairly small hole where they were driven in. They’re shown as having small round bulges on their length (but not, say, hooks) but the mechanics of **pulling** the wall out (when it is under tremendous compression!) seems pretty unlikely.

Instead, just like the better solution to the ‘collapse the mountain with catapults’ tactic – which some commenters have noted, in suggesting they might do it with late 19th century naval artillery, I was apparently still something like an order of magnitude or two off in terms of how much explosives they’d need – the solution here is very simple: orcs with pickaxes.² If you have unfettered access to the base of the wall, no fancy torsion machine is necessary and indeed the machine does you no favors. After all, you go through all of the effort to drive a metal spike into the wall, there’s a good chance when you pull on it, it is going to tear out and bring very little of the wall with it, for the same reason that pulling a nail out of your wall does not collapse your house. But if you are just using pickaxes to chip and smash the stones until they crumble…well, that is how mining rock is done and for a reason.³

So the way you would actually do this would be that once the river was drained, orcs would go forward and – probably using portable mantlet barriers with roofs on them to approach safely – assemble a fortified wooden shelter at the wall’s base. Then orcs with pickaxes and hammers could shatter and split the stones to undermine the wall. This sort of much simpler and more effective way of defeating a wall was frequently practiced, although operating on the surface near the enemy walls was an obvious liability, since defenders might sally out and contest the work site. As a result, even more common than surface undermining – at least as far as I can tell, it appears more commonly in siege accounts – was starting a tunnel some distance from the wall and advance it underground to the wall and then collapse it (bringing the wall down in the process). Such mining warfare was an extremely common part of siege warfare from antiquity onward, leading defenders to devise means of trying to detect undermining efforts, like a thin bowl filled with water, where the vibrations of the mining effort will cause ripples in the water, alerting the defenders.⁴

One thing I hope comes out clearly here is how complex siege warfare could be. Systems of field fortifications, moveable shelters, siege engines, earthworks, mining and so on all brought to bear against a defender in order to degrade and eventually breach defenses that would have easily resisted a simple sudden assault ‘like swarming ants.’ Taking a walled city with nothing but muscle power was an extensively theorized problem in the pre-modern world. It is always perilous to say of any activity that every angle was considered, but surely most of them were. Sieges were rarely won by the clever application of a never-before-seen technology and far more frequently won by the methodical, careful application of very well known, frequently ancient, techniques.

Conclusions

From a historical perspective, Adar’s assault on Ost-in-Edhil is basically nonsense. He does almost everything that ought to cause such an assault to fail badly but succeeds easily because the plot requires it and this is Rings of Power, where nothing matters. Adar launches an unprotected assault with largely unarmored infantry over difficult terrain into archers positioned atop a stone wall, supported only by ladders (delivering his relatively light infantry into contact with plate-armored defenders) and a nonsense breaching machine, while his catapults do nothing to support the attack and instead sit idle. His men attack “like swarming ants,” but win anyway, because in this show, nothing matters.

Pictured: Adar’s forces, advancing “like swarming ants.”

From a storytelling perspective, I think the assault is also a failure. It doesn’t serve to really illuminate Adar’s character or Celebrimbor’s. We’re supposed to understand that Adar is being wasteful with the lives of his orcish ‘children,’ but in a battle where the casualties don’t matter and Adar has infinite respawning orc armies, this doesn’t matter. We’re never really confronted with Adar’s decision to sacrifice his troops except in seeing unnamed mooks mowed down in the background in a language film has used to just say “this is a battle” for ages. Adar’s orcs take basically the same losses to arrows as Théoden’s riders or Alexander’s phalanx in Alexander (2004) and those are commanders we understand (in the story, if not in reality) care quite a lot about their men. Whereas Peter Jackson’s films largely succeed in communicating character in these battles (even if they miss some of Tolkien’s details), Rings of Power largely fails.

But even beyond this, the decision to go with ‘Hollywood tactics’ misses an opportunity to do something new and fresh by drawing on the historical material more closely. As an aside, I think this is true of quite a few aspects of how pre-modern societies are portrayed: dispensing the tired Hollywood tropes of ‘Flynning‘ sword-fights and mud-brown hovels for historical fencing and appropriately brightly painted sets would do a lot to make a given project feel new and different.⁵

In the case of a siege, utilizing actual siege tactics offers quite a lot of narrative potential, particularly in the form of the slower-burning prestige streaming TV format, where the time pressures of film are quite a bit less and it is much easier to utilize montage and cuts to imply the passage of time. The emotional strain of a siege on the defenders was considerable: they had to watch, largely unable to interfere, while the attackers methodically prepared on stage of the attack after another. In a show built around parallel storylines, such a siege could easily run several episodes in parallel with other stories, giving us a sense of how hopeless the defense is as the attackers surround the city, fortify their positions, begin a slow, steady bombardment of the defenses, build moles and bridges over the river, set siege towers to overawe the walls, and then begin slowly crumbling their foundations with pickaxes from defended, covered shelters, all while the defenders struggle to do anything to even really slow this effort down. If you still need the sense of Adar’s callousness to his orcs, a long siege gives you an opportunity to tell this story logistically, as his orcs steadily run short on supplies and he remains brutally committed to the effort.⁶

Instead we get a sequence that repeatedly struggles to believably connect action with consequence. Adar aims his catapults at a solid rock face ten miles away and this somehow produces exactly the dam he needs to enable this assault. He then runs his orcs pell-mell over a muddy basin still filled with pockets of standing water, pushing a gigantic, heavy machine whose workings make no sense, and this results in such a successful siege assault that being unexpected attacked in the rear twice will do nothing to slow it down.

And that’s where we’ll turn next week: the cavalry arrives but – because this is Rings of Power – it doesn’t matter either.

Antitrust is just not going to rouse the masses

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Transcript:

What Is Dong Quai?

What Is Menopause and Its Symptoms?

What Is the Connection Between Dong Quai and Menopause?

How To Take Dong Quai

How To Combine Dong Quai With Other Remedies

What Are the Potential Risks of Dong Quai?

Move Through Menopause With Confidence Thanks to Dong Quai

Welcome to a much overdue edition of this newsletter.

My Substack: Live From California

Burning Man 2024

Video showing the flashing lights

Baja California Sur Revisited

Deep in the Heart of Baja(the title of a book on Baja California I’m gonna do one of these years)

A Tip of Hatlo Hat to Rick Gordon…

A Complete Unknown

La Vida en Solitario

The Potion is Motion

Aging

Finding Usefulness in the Villainous

The iPhone

Google

Instagram

Facebook

Amazon

Apple

Artificial Intelligence

The Marriage of Heaven and Hell

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Illustration

Workflow & Activation Energy

Consequences

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Swarming Like Ants

Making Works Work For Your Work

Orcish Machines

Conclusions

Cuts and Keeps

Spending Goes On

What About the Politics?

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The Crowd Makes It Clear More of This Is Wanted

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Deep in the Heart of Baja
(the title of a book on Baja California I’m gonna do one of these years)