Why didn’t the Roman Empire have an industrial revolution?

Bret Devereaux has an essay addressing that question, which multiple people have pointed me to at various times. In brief, Devereaux says that Britain industrialized through a very specific path, involving coal mines, steam engines, and textile production. The Roman Empire didn’t have those specific preconditions, and it’s not clear to him that any other path could have created an Industrial Revolution. So Rome didn’t have an IR because they didn’t have coal mines that they needed to pump water out of, they didn’t have a textile industry that was ready to make use of steam power, etc. (Although he says he can’t rule out alternative paths to industrialization, he doesn’t seem to give any weight to that possibility.)

I find this explanation intelligent, informed, and interesting—yet unsatisfying, in the same way and for the same reasons as I find Robert Allen’s explanation unsatisfying: I don’t believe that industrialization was so contingent on such very specific factors. When you consider the breadth of problems being solved and advances being made in so many different areas, the progress of that era looks less like a lucky break, and more like a general problem-solving ability getting applied to the challenge of human existence. (I tried to get Devereaux’s thoughts on this, but I guess he was too busy to give much of an answer.)

How close did we come?
How close did we come?

As a thought experiment: Suppose that British geology had been different, and it hadn’t had much coal. Would we still be living in a pre-industrial world, 300 years later? What about in 1000 years? This seems implausible to me.

Or, suppose there is an intelligent alien civilization that has been around for much longer than humans. Would you expect that they have definitely industrialized in some form? Or would it depend on the particular geology of their planet? Are fossil fuels the Great Filter? Again, implausible. I expect that given enough time, any sufficiently intelligent species would reach a high level of technology on the vast majority of habitable planets.

Devereaux asserts that there is a “deeply contingent nature of historical events … that data (like the charts of global GDP over centuries) can sometimes fail to capture.” I see this in reverse: the chart of global GDP over centuries is, to my mind, evidence that progress is not so contingent on random historical flukes, that there is a deeper underlying process driving it.

Would this long-run trend have been cut off in the middle, but for the lucky break of Britain's coal mines?
Would this long-run trend have been cut off in the middle, but for the lucky break of Britain's coal mines? Credit: Paul Romer

So why didn’t the Roman Empire have an industrial revolution?

Consider a related question: why didn’t the Roman Empire have an information revolution? Why didn’t they invent the computer? Presumably the answer is obvious: they were missing too many preconditions, such as electricity, not to mention math (if you think ENIAC’s decimal-based arithmetic was inefficient, imagine a computer trying to use Roman numerals). Even conceiving the computer, let alone inventing one, requires reaching a certain level of technological development first, and the Romans were nowhere near that.

I think the answer is roughly the same for why no Roman IR, it’s just a bit less obvious. Here are a few of the things the ancient Romans didn’t have:

  • The spinning wheel
  • The windmill
  • The horse collar
  • Cast iron
  • Latex rubber
  • The movable-type printing press
  • The mechanical clock
  • The compass
  • Arabic numerals

And a few other key inventions, such as the moldboard plow and the crank-and-connecting-rod, showed up only in the 3rd century or later, well past the peak of the Empire.

How are you going to industrialize when you don’t have cast iron to build machines out of, or basic mechanical linkages to use in them? How could a society increase labor productivity through automation when it hasn’t even approached the frontier of what is possible with simple wooden tools? Why even focus on improving labor productivity in manufacturing when productivity is still very low in agriculture, which is more fundamental? Why should it exploit coal when it has barely begun to exploit wind, water, and animal power? How are engineers to do experiments and calculations without any concept of the experimental method, and without anything close to the mathematical tools that are available today to any fifth-grader? And if anything was discovered or invented, how could the news spread widely when most information was hand-written on parchment?

All of the flywheels of progress—surplus wealth, materials and manufacturing ability, scientific knowledge and methods, large markets, communication networks, financial institutions, corporate and IP law—were turning very slowly. There is not a single, narrow path to industrialization, but you have to get there through some path, and ancient Rome was simply nowhere close. You can’t leapfrog over the spinning wheel to get to the spinning mule, and (this is one thing we learn from Allen’s analysis) it’s not clear that it even makes economic sense to do so.

In a sense, I’m saying the same thing as Devereaux: Rome couldn’t have had an IR because they didn’t have the preconditions. But rather than conceiving of those preconditions as very narrow and seeing the IR as highly contingent, I am taking a much broader view of the preconditions.

If Rome hadn’t collapsed, they might, within a matter of centuries, have advanced to the stage of industrialization. But they would have done it by skipping the Dark Ages and following an incremental course of technological and economic advancement that, if not identical to ours, would probably be not unrecognizable, and perhaps quite familiar.

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If Rome hadn’t collapsed, they might, within a matter of centuries, have advanced to the stage of industrialization. But they would have done it by skipping the Dark Ages and following an incremental course of technological and economic advancement that, if not identical to ours, would probably be not unrecognizable, and perhaps quite familiar.

Doesn't this then lead us to the question of why no Chinese IR?

Yes, the famous Needham question. It is tougher to answer. Mokyr offers some thoughts in A Culture of Growth. I'm sure there are other hypotheses but I don't have pointers right now.

My suspicion is that it has to do with cultural-cognitive developments generally filed under "religion". As it's little more than a hunch and runs somewhat counter to my impression of LW mores, I hesitate to discuss it in more depth here.

Nick Szabo thinks that Europe's history of relatively high intensity in use of animal labor helped it undergo the industrial revolution. One of the first uses of the steam engine was pumping water out of mines--at a time when the status quo was to use horses and oxen to do the same thing. He shows street scenes of China in the 1900s where there is a lot of transportation of heavy loads going on--all done by human labor.

The people of northern Europe were not the first to domesticate cows, but they were the first farming (i.e., non-nomadic) people to domesticate cows on a large scale--many millennia ago. Domesticated animals have been important in Europe ever since--more so in northern Europe than southern Europe (getting back to the original question of why no Roman industrial revolution). The Romans had cavalry because it was an important component of military force, and they certainly weren't going to ignore a significant military factor, but they were much more likely to "outsource" cavalry to non-Romans than to "outsource" infantry, which is a sign that domesticated animals were less important in Roman society than they were in surrounding areas.

I see there as being (at least) two potential drivers in your characterization, that seem to me like they would suggest very different plans for a time traveling intervention. 

Here's a thought experiment: you're going to travel back in time and land near Gnaeus Pompeius Magnus, who you know will (along with Marcus Licinius Crassus) repeal the constitutional reforms of Sulla (which occurred in roughly 82-80 BC and were repealed by roughly 70BC).

Your experimental manipulation is to visit the same timeline twice and either (1) hang out nearby and help draft a much better replacement to Sulla's reforms in ~76 BC to ~70 BC (and maybe bring some gold to bribe some senators or whatever else is needed here to make it happen?) or else (2) bring along some gold, and simply go hire a bunch of honest hard-working smiths to help you build a printing press anywhere in the Roman world, and start printing dictionaries and romance novels and newspapers and so on, and keep at it until the printing business becomes profitable because lot of people picked up literacy because doing some was easier for them to cheaply get value from, because there was a bunch of good cheap written materials!

Then the experimental data you collect is to let various butterflies float around... and resample 100 chaotic instances each of "20 AD" (for a total of 200 samples of "20 AD") and see which ones are closer to an industrial revolution and which ones are farther from one.

This is one set of things that might be missing (which could potentially be intervened on politically in the aftermath of Sulla):

All of the flywheels of progress — ...large markets... financial institutions, corporate and IP law—were turning very slowly.

And this is a different thing that might be missing one (that could be intervened on any time, but doing it when the Sulla/Pompey/Crassus intervention is possible helps with a ceteris paribus comparison):

All of the flywheels of progresssurplus wealth, materials and manufacturing ability, scientific knowledge and methods, ...communication networks...—were turning very slowly.

If the problem was bad and declining institutions, then the first intervention will help a lot more to get you to a prosperous ancient world without needing to go through the intervening dark age.

But if the problem was a lack of technologists with time and funding and skills to make the world better then the second intervention will probably help a lot more.

To be conceptually thorough, you could try to have a four way experimental design, and have two more time traveling trips, one of which is "both interventions" and the other just injects some random noise in a way that counts as "neither innovation". 

I think if "there is only the ONE BIG CATEGORY OF THING that's really missing" then there will be enormous leaps in the "both" timelines, and all 300 other sampled "20 ADs" (that got the "neither", "just tech", or "just laws" intervention) will all still be on course for a dark age.

To be clear, I don't mean to say that this is the only way to "divide your proposed flywheels of progress" into two chunks. 

Maybe the only real flywheel is wealth (and it is just about doing an efficient build-out of good infrastructure), or maybe the only real flywheel is large markets (because maybe "specialization" is the magic thing to unlock), or maybe it is only knowledge (because going meta always wins eventually)?

There's a lot of possibilities. And each possibility suggests different thought experiments! :-)

Seems basically correct to me. It's a bit of a boring answer in a way. Difficult to write vast academic tomes if it's a simple underlying progress. 


I have not studied this issue in detail.  However,

What about the printing press?  My pet theory that is not validated by historians is:

Printing press makes it possible to create many instances of a text containing knowledge, inexpensively.

With more literate readers having access to libraries of books, it allows someone to actually notice when information is contradictory.  If you only ever have 1 text on a subject, there's nothing to compare to.

This ultimately led to an evolution of rules, what we call the Scientific Method, where you need:

  1.  falsifiable idea
  2. Peers (which presumably meant other wealthy people, today it seems to be mean high status PhD holders) must review before publication
  3. Publish a Paper in a high status journal
  4. Use mathematics to analyze the probabilities

And so on, though each element must have been gradually evolved. 

The drive force that led to all these rules is that if you have a library and many copies of information on the same topics, you will start to notice all the contradictions and conclude all existing knowledge is probably junk.  Hence the above.  (and I think AI systems will be able to do the same thing on a larger scale)

Anyways, this is what you need to do to put together enough complex ideas to make industrialization possible.  The steam engine alone required designs and high quality metallurgy and contributions of materials and knowledge from a broad base of contributors.   And it required a way to record the design and record the theories and distribute the information to other people, so that followup inventions could be made.  

There likely were many ways to harness energy from nature and industrialize.  The obvious being that you didn't need coal, water wheel powered factories would work until you ran out of rivers to dam, which was only a problem late in industrialization.  

* There are also enormous holes in the current scientific method and you could replace it with :

          1.  idea that can be analyzed probabilistically, you don't have to be able to prove it false, just more or less likely to be true

          2.  Multiple AI systems who have been validated find no obvious errors in calculations or methodology

          3.  Publish the raw data and robotic steps taken to generate and initial analysis

          4.  Other robotic systems will use the robotic steps to reproduce, until then the analysis is not considered published

          5.  Many AI systems will be able to use a variety of methods to analyze the raw data, and the initial analysis will be discarded (because any paper that uses old technique f1 on n fields of data is strictly less useful than one that uses new proven better technique f2 on n + m fields of data)

I think everything you say about the printing press is correct and important, I would just caution against overfocusing on the printing press as the one pivotal cause. I think it was part of a broader trend.


Per the link you cited:

There must be some very deep underlying trend that explains these non-coincidences. And that is why I am sympathetic to explanations that invoke fundamental changes in thinking

The question then converts to : why did this happen when it happened, and not earlier or later?  The "printing press theory" proposes that people could not change their thinking without the information to show where it was flawed (by having something to compare to), and the other critical element is it's a ratchet.

Each "long tail" theory that someone writes down continues to exist because a press can make many copies of their book.  Prior to this, ideas that only sort of worked but were not that valuable would only get hand copied a few times and then lost. 

This is one of the reasons why genomes are able to evolve : multiple redundant copies of the same gene allows for 1 main copy to keep the organism reproducing while the other copies can change with mutations, exploring the fitness space for an edge.  


If you think about how you might build an artificial intelligence able to reason about a grounded problem, for example a simple one:  Pathing an autonomous car.

One way to solve the problem is to use a neural network that generates many plausible paths the car might take over future instants in time.  (anyone here on lesswrong has used such a tool)

Then you would evaluate the set of paths vs heuristics for "goodness" and then choose the max(goodness(set(generated paths))) to actually do in the world.

Similarly, an AI reasoning over scientific theories need not "stake it's reputation" on particles or waves, to name a famous dilemma.  It's perfectly feasible to simultaneously believe both theories at once, and to weight your predictions by evaluating any inputs against both theories, and to multiply how confident a particular theory is it applies in this domain.  

An AI need not commit to 2 theories, it can easily maintain sets of thousands and be able to make robust predictions for many situations.  As new information comes in that causes theory updates, you mechanistically update all theories, and drop the least likely ones and generate new ones.*

I bring up the AI example to create a shim to see how we should have done science (if we had much higher performance brains), and thus explain why becoming even slightly less stupid with the ability to mass produce paper with text allowed what it did.

When you can't mass produce paper, you're stuck with 1 orthodox way to do things, and thus you just keep recopying stuff written centuries before, because the new idea isn't good enough to be worth copying.

A real life analogy would be how streaming video remove the cap on "TV airing slots" and has allowed an explosion in creativity and viewership for even niche foreign shows that would never have received an airing in the US tv market.  (squid game)

*this is also the correct way to do a criminal investigation.  Start by suspecting every human on the planet, and many natural and accidental mechanisms, and update the list with each new piece of evidence.  Once enough probability mass is on one individual you know who probably did it, and an honest investigator would make clear the exact probability numbers to any decisionmakers for punishment.  


Conclusion: I'm not saying it's only the printing press, but there would have to be other changes in human civilization enabled by technology that allowed a shift in thinking to happen.  Otherwise it could have happened over many prior centuries.  Something like "availability of coal" or "we were doing a lot of sailing in ships" each was possible from an underlying technology change that wasn't available to the romans.


Don't forget one ingredient that Rome had in (relative) abundance, which is slaves.

It's not as if the Romans had no idea what they could do with improved mechanics. They just didn't see the point, esp. as the slaves would then be out of work.


I have to second this comment. As a classicist, the common factor throughout a lot of Roman stagnation is that you just simply do not have the incentive to create mechanical options if you have a (seemingly) limitless number of slaves to do your tasks for you, from working in mills to mining silver to being your doctor and your tutor and so on. It's also probably one of the factors that led to such a total and sudden loss of knowledge on a lot of subjects once the entire thing collapsed, because once you're no longer forced to stay with your "owner" on pain of violence you leave. 

Roman/Greek/Mediterranean slavery was technically much more livable than say, 19th century American chattel/racialized slavery, but it was still very bad, and very ubiquitous. And you can actually see parallels to the question in the 19th Century American Slave-owning South; it would have been much more financial expedient for the South to have mechanized, but the planters were ideologically attached to the slave system, and chose being plantation owners with slaves over more efficient industry. 

I do think the Roman empire actually had the preconditions for some kind of industrialization, though maybe not an entirely familiar one; there were Greek inventors who created small steam-powered devices, after all. But these, like a lot of things that would seem familiar to us, were considered mostly intriguing toys, because once again, there is no reason to make a labor-saving device when you can simply go somewhere and steal people to do that labor. 


I am still not convinced. Slaves, although seemingly limitless, are not free. At the very least, you have to feed them. Why not give them mechanical tools to increase their productivity?

This is a very popular theory, but it seems to predict way too much. The Greeks and Romans did have animal powered wells and mills. They had water mills and water saws. They probably had windmills.

Exactly! Why innovate when you can enslave? Why wasn’t the Antebellum American South industrialized? Slavery kills the impetus to reduce labor.

Counterpoint: The American South very quickly adopted one of the classic inventions of the Industrial Revolution, the cotton gin. And it has been proposed that this actually helped entrench slavery in the South.

Before asking why, ask what. Why did the technological growth of ancient Rome not snowball into the industrial revolution? I reject the premise. Rome was a period of regress in both physical technology and social organization, although it did spread some technology westward.

More generally, the macro trends of history are largely fabricated to prove the desired conclusion that there is always exponential progress, except in a few collapses that are so sharp that they cannot be denied. Why did this growth not produce the industrial revolution? Because it wasn't progress.

I’m not claiming this view to be particularly well informed, but it seems a reasonable hypothesis that the industrial revolution required the development, dispersement and application of new methods of applied mathematics. For this to happen there needed to be an easy-to-use number system with a zero and a decimal point. Use of calculus would seem to be an almost essential mathematical aid as well. Last but not least there needed to be a sizeable collaborative, communicative and practically minded scientific community who could discuss, criticise and disseminate applied mathematical ideas and apply them in physical experiments. All these three items were extant in Britain in the late 17th century, the latter being exemplified by the Royal Society. These, combined with the geologically bestowed gifts of coal and iron ore, would set Britain up to be in the best position to initiate the Industrial Revolution.

Now, can a proper historian of science critique this and show how this view is incorrect?


I'm including this wikipedia article because it's actually a pretty good summary of the text/writer in question: https://en.wikipedia.org/wiki/Vitruvius. 

While I agree that their counting system was not super useful for a lot of complicated mathematical or theoretical stuff, what you get instead is a lot of architecture, engineering, etc. that has familiar ideas in different terms. What you see if you look into the technology Vitrivius described is that they had a lot of "industrial" things (cranes, siege engines, etc.) but these were all constructed/powered using slaves. 

You can also see that the Romans were aware of primitive steam technology. My personal understanding for why they didn't develop it further was that they had no ideological or financial reason to stop using slaves for all brute mechanical tasks, and since slaves were so disenfranchised, there was no reason to find ways of replacing them. 

Medieval china had spinning wheel, compass, printing press, clocks, banking, factories, gunpowder, etc, and still did not industrialise.

Yes, see my reply to Vaniver above.

I think "Why The West Rules", by Ian Morris, has a pretty informative take on this.  The impression I got from the book was that gradually accruing technologies/knowledge, like the stuff you mention, is slowly accruing in the background amid the ups and downs of history, and during each peak of civilizational complexity (most notably the Roman empire, and the medieval-era Song Dynasty in china, and then industrial-era Britain) humanity basically gets another shot-on-goal to potentially industrialize.

Britain had a couple of lucky breaks -- cheap and abundant coal, but also the way that the industrial revolution was preceded by the growth-boosting effects of transatlantic contact.  (For instance getting all kinds of new foods from the New World, like potatoes, which then boost agricultural output across Europe.  And the ways that putting on big risky trans-oceanic expeditions incentivized the development of corporate structures / capitalism / etc.  And just having a century of positive-sum growth puts everyone in a good frame of mind in terms of being motivated and risk-tolerant and seeking opportunities, rather than there being tons of conflict.)

So, in that sense, maybe the industrial revolution "came early" due to these lucky breaks, and otherwise would have been delayed for another century until, say, Germany or the USA started digging up coal (or oil, or some other energy source) even if Britain didn't have any.

Unrelated: fellow fans of Morris's book might appreciate my parody blog post "Why The East Rules -- For Now".


The most convincing answer I've come across is from Greg Clark at UC Davis. A long-run process of Malthusian conditions eventually led to significant changes in the human capital stock which enabled the Industrial Revolution. Some notable examples of apparent differences in average traits between Romans and Pre-Industrial England:

  • Interest rates (risk-free rate around 10-20% in Roman times vs 3% in 1800 England)
  • Violent tendencies (likely high murder rate and atrocities as entertainment in the Colosseum vs lower murder rate in 1800 England than in modern America)
  • Literacy/Numeracy (most Romans did not know their exact age and likely could not read vs 70-94% rate of numeracy and ~50% rate of literacy in 1800 England)
  • Work hours (harder to measure but it looks like people in 1800 England worked about 20% more than people in Medieval England)

The trends noted above have much better data for Medieval England than Ancient Rome, but the direction of travel is quite clear and likely would apply to Ancient Rome. Greg Clark has an entire lecture series on this general topic on Youtube, highly recommended. 

"I see this in reverse: the chart of global GDP over centuries"

but that's just a modernist version of the weak anthropic principle

i.e. you only have a chart of rising per capita GDP for the past few centuries because in order to belong to a society that does things like produce charts of per capita GDP, you'd have to see rising per capita GDP in your recent past

progress was quite slow for at least tens of millennia until rather suddenly a number of contingent factors conspired to create the conditions for industrialization, most particularly new attitudes toward human slavery

but it's very easy to misread technological progress for commercial/social progress

why didn't Romans use spinning wheels or windmills or animal labor? because slaves were cheaper 

why didn't Romans do more agricultural engineering? because taking Egyptian grain was cheaper

why didn't Romans develop better math? because they had Greek slaves for bookkeeping and little need for complex non-military engineering (again, slaves)

why didn't Romans develop metal movable type? clay was cheaper and if you need lots of copies you just bought more slaves (the printing press in particular seems to belong to a historically very peculiar Protestant notion that everyone should read the sacred texts)

why did Ali Pasha bring all his wealth to battle at Lepanto, while the merchants of Venice financed the casting of some of the most sophisticated weapons yet built with money safely hidden in banks? Europe had sophisticated credit markets, the militarily stronger Ottoman state did not

why did the Queen of England initially ban power looms? she was afraid it would put weavers out of work

everything is deeply contingent

most contingent of all, of course, was the scientific revolution, dependent on a notion of "free inquiry" so unusual to human societies it arose only once and has been under constant attack ever since (despite being inarguably priceless)

progress only looks inevitable in retrospect because once anyone succeeds in raising productivity, others must imitate or fail

Another factor might the development of modern engineering drawing, which showed much better what a machine did and how it did it.  Modern engineering drawing was developed around the beginning of Industrial  Revolution and would have helped spread the new ideas much better than anything that existed before. So, it became much easier to build what others had built, and, even more importantly, tinker with it to improve it.

What if the key to the "industrial revolution"  wasn't an industrial problem to solve? What if banking/finance and risk transfer were the key? Inventors don't come with money; those with money don't want to take unlimited risks with their money, plus a whole host of intermediaries - managers, insurance, and accountants.

Or, suppose there is an intelligent alien civilization that has been around for much longer than humans. Would you expect that they have definitely industrialized in some form? Or would it depend on the particular geology of their planet? I think the answers are "no" and "yes". No fossil fuels, no cheap energy, no industrial revolution ever. There might be a different way through hydroelectric power, but that requires cheap copper.


Alternative hypothesis: it’s all about Malthus trap. Humanity took off exactly when the snowball effect of knowledge accumulation start inducing more economical growth that human fecondity could compete with. I like the idea because it then explain China as well, but I didn’t start looking for hard evidence so feel free to share this kernel.

Except my intuition is that the Roman’s managed to evade mathlusian living conditions.

Partial evidence: slavery an institution makes very little sense at the mathlusian boundary. Why pay for a slave when human labor costs the amount of food that it covers. (That’s the price of human labor in a mathlusian world)

Slaves reproducing themselves is nonmalthusian, but rare. Romans captured slaves in war and enslaved debtors. I think the only time in history chattel slaves reproduced themselves is the New World, which was quite nonmalthusian.


Ancient British history is deliciously weird, and a rabbit hole with many enjoyable documentaries. I'm fascinated by how many of the tropes and traits we associate with the region today actually seem to have been Roman in origin.

One factor to consider is simple geography: Island ecosystems of any type experience different constraints from larger ones.

Another factor is climate: An island that fluctuates between habitable and uninhabitable climate on the geologic time scale develops differently from a region that's more stable.

I have the impression that capacity to invent a given technology and cultural receptivity to adopting that technology are a whole lot less tightly coupled than it's often convenient to assume.

Certainty that the old ways of doing things have served one's ancestors well since time immemorial is a powerful innoculant against change. Kinda like how it's harder to try a new dish at a restaurant that has your favorite food in the world as an option on its menu. I think a shorter tradition of "this is definitely the right way to farm/mine/craft here" will be more receptive to potential improvements than a longer and more certain tradition.