A (Very) Short History of the Collapse of Civilizations, and Why it Matters

by Davidmanheim4 min read30th Aug 202016 comments

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Civilizational collapseHistoryExistential risk
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If we are worried about risks to society as a whole, one valuable question is whether there have been historical analogues and/or near misses. The current dislocation, prompted by the pandemic, but by no means limited to that, seems like a worrying piece of evidence. In the post, I review the basic fact that previous collapses have occurred, and then talk a bit more about whether the evidence matters.

Related Posts: Pawntoe4's On Collapse Risk (C-Risk), landfish's Update on civilizational collapse research, MichealA's Sources on Civilizational Collapse Risks, and Denkenberger's Loss of Industrial Civilization and Recovery (Workshop)


Can civilizations collapse? (Yes.)

Local collapses have long-occurred, from the collapse of Mesopotamia more than four millennia ago, due to drought and agricultural failures, to the decline of Greece, due largely to political infighting, to the fall of the Roman, Ghanan, Malian, or Songhai Empires, each due to a combination of politics, economics, and external invasions. In each case, the populations suffered, many died, and none ever recovered their pre-eminence. This seems like an obvious catastrophe, but short of an existential risk.

However, a collapse like that of the Roman empire has effects that last for centuries even when recovery occurs. The recovery came slowly, despite the Merovingians, then Carolingians, then the Holy Roman Empire and the Muslim world attempting to continue or build upon various parts of Roman civilization and scholarship - and each themselves collapsing before even reaching the level the Romans managed. Global civilization could fall far more precipitously, with even less ability to recover.

How Frequent are Collapses?

This is unclear, and plausibly important. Luke Kemp at Cambridge CSER has a short review of ancient civilizations, which seems fairly useful at getting a better handle on this. But similar to my argument about people's former underestimation of risks from natural pandemics, I think there are good reasons to treat the historical evidence as partial, and as a lower bound rather than a strong prior.

It seems unclear how often these were supplanted, conquered, or dissolved / crashed. Documentation of crashes is partial, and depends on having records that are clear. Many conquered nations were plausibly ready to collapse, and simply failed to have a hydraulic empire dynamic that made collapse, rather than revolt or invasion, the only option. Today's civilization is similar in some ways, but as the world gets smaller, there is no outside culture to invade.

What does this imply about Modern Civilization?

As noted above, it seems unclear how historical events matter for larger scale risk now in various ways- not that they aren't evidence, but it's unclear how to use the base rates usefully. Many of these failure modes which were local then, and didn't have knock-on impacts, could be more critical now. On the other hand, they may be less critical given interconnections.

Modern global civilization is more robust to many types of failure, more unified, and in some ways more fragile. A local collapse could be contained, as happened after the devastation of Europe during World War Two, or the former Soviet block after the fall of communism. In each case, the shock was absorbed by the larger global economy, and the local impacts were drastic and lasted decades, but the decline in living standards was short term, on the order of a single lifetime, and it seems clear that global progress more than compensated in the medium term.

A global collapse, however, would plausibly leave no outsiders or successors to pick up the baton, as Rome did for Greece. The lack of successors to pick up the pieces, along with the availability of weapons that could wipe out all human life, and global-scale threats like climate change, makes a modern collapse at least plausibly far more dangerous for humanity's future. And even if the collapse isn't global, even a single major actor's collapse, like the fall of the Soviet Union, or the seemingly still-ongoing collapse of the United States, greatly increases certain risks.

The Future / Post-Script

I just wrote a paper on technological collapse and fragility, entitled The Fragile World Hypothesis, making the much more abstract case that there is at least one mode where a water-empire collapse happens to humanity, and is an existential rather than just catastrophic threat. In the paper, which was just published in print, I argue that fragility of technological systems is increasing, and it does so in ways we should be worried about far more for the future. I won't repeat that argument here.

The above post is mostly from some notes from that paper which were cut because they were not critical for the main claims, but I think they are worth presenting as a reminder that collapse isn't as rare as we might assume. It also seems worth building more understanding around the cases which occurred in the past, and how it does or doesn't inform our current concerns - I'd be happy to see people do more work on this. This seems like a great place for a non-technical social scientist research project to make a significant contribution - but only if it's done a bit more rigorously than a post like this one. Feel free to be in touch.)

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(I think this comment isn't important for the core points of this post.)

In each case, the populations suffered, many died, and none ever recovered their pre-eminence. This seems like an obvious catastrophe, but short of an existential risk.

Do you mean "an obvious catastrophe from the perspective of the regimes that had ruled those civilizations"?

I think it's not obvious that all/most societal collapses in history have been catastrophes from the perspectives of those society's populations, let alone the perspectives of the world. See, for example, the book Against the Grain, which:

sets out to undermine what he calls the "standard civilizational narrative" that suggests humans chose to live settled lives based on intensive agriculture because this made people safer and more prosperous.[1] Instead, [the author] argues, people had to be forced to live in the early states, which were hierarchical, beset by malnutrition and disease, and often based on slavery. (Wikipedia)

(Though we could theoretically accept the latter view and yet still think collapses were negative for the people in those societies, because of the related turmoil.)

But this is mostly a nit-pick/tangential query, because: 

  • I think a strong case can be made that modern liberal democratic states have improved wellbeing (even if early states didn't)
  • I think a strong case can be made that a global collapse from our current civilization would worsen humanity's long-term trajectory
  • I think we could even believe the latter case without believing the former case

This was imprecise - I meant that collapses were catastrophes for the civilizations involved, and current collapses would also be catastrophes, one which I agree would be significantly worse if they impacted humanity's longer term trajectory. And yes, some collapses may have been net benefits - though I think the collapse of early agricultural societies did set those societies back, and were catastrophes for them - we just think that the direction of those societies was bad, so we're unperturbed that they collapsed. The same would be said of the once-impending collapse of the antebellum South in the US, where economics was going to destroy their economy, i.e. slavery. But despite the simplicity of the cause, slavery, I will greatly simplify the political dynamics leading to the outbreak of the civil war and say that they started a war to protect their culture instead of allowing the North to supplant them. This seems like a clear civilizational catastrophe, with some large moral benefits from ending slavery.

I think that unlike the Antebelllum south, and early exploitative agricultural societies, the collapse of Rome was also a collapse that hurt civilization's medium-term trajectory, despite taking quite a long time. And I'm hoping the ongoing collapse of the post-WWII international order isn't a similar devolution.

Thanks for the post. I wonder if one the great gaps in education (at least for me), that prevents people from becoming more concerned about the longterm future, is the lack of emphasis on civilization collapses - as much as the lack of emphasis on the progress and the risks from the last 110 years.

Thanks for this post.

It also seems worth building more understanding around the cases which occurred in the past, and how it does or doesn't inform our current concerns - I'd be happy to see people do more work on this. This seems like a great place for a non-technical social scientist research project to make a significant contribution

I strongly agree. 

I've also developed some thoughts on a potential research project in this area (as you and I have discussed), so if other people are interested, feel free to reach out to me as well. It's possible other people would be a better fit than me for the project, in which  case I can just palm it off to them, if they're interested. Or we could just discuss related ideas in this space. 

(I'll probably post something on my project idea in a few weeks.)

Many conquered nations were plausibly ready to collapse, and simply failed to have a hydraulic empire dynamic that made collapse, rather than revolt or invasion, the only option. Today's civilization is similar in some ways, but as the world gets smaller, there is no outside culture to invade.

To check I understand, is the argument here essentially the following? "There may have been many societies that would have collapsed relatively soon after they were conquered.[1] Thus, if conquest was not possible, there may have been more collapses in the past. Nowadays, there is no outside civilization that can conquer our civilization, which may mean collapse risk is higher than one would have thought based on historical base rates."

If that is the argument, I'm not sure I fully buy/understand it. Some thoughts:

  • I believe invasion is often seen as a common factor contributing to collapse. So if invasions couldn't happen, I'd have thought there'd have been less collapses? So wouldn't this suggest that, if invasions can't happen in the modern day, we're more safe from collapses than historical base rates would suggest?
  • In what sense is there "no outside culture to invade"?
    • It still seems like great power wars are very possible.
    • It does seem like there are important senses in which the world in more unified (culturally, economically, etc.) than before. But even given that, I'm not sure what "there is no outside culture to invade" should mean, or what it should imply if true.
    • (This question is more genuine than rhetorical.)

[1] After David replied, I re-read this, and felt that the first sentence would've been more clearly stated as "Many societies that were conquered may have been close to collapsing already, had they not been conquered."

The first issue is that my question was whether civilizations collapse - in the sense that the system collapses to the point where large portions die - infrequently or very infrequently. The argument is that conquered civilizations are "missing data" in that it seems very likely that an unstable or otherwise damaged society that has a higher chance of collapse, whether due to invasion or to other factors, also has a higher chance of being supplanted rather than us seeing a collapse. So I noted that we have data missing in a way that introduces a bias.

The second issue is what a collapse would look like and involve. Because civilization is more tightly interconnected, many types of collapse would be universal, rather than local. (See both Bostrom's Vulnerable world paper and my Fragile world paper for examples of how technology could lead to that occurring.) Great power wars could trigger or accelerate such a collapse, but they wouldn't lead to decoupled sociotechnical systems, or any plausible scenarios that would allow a winner to replace the loser.

Does that make sense?

So I noted that we have data missing in a way that introduces a bias.

Hmm, I don't know. I think I get what you're saying, but it feels analogous to saying "If no one died in car accidents, more people would die of heart attacks. So we have data missing in a way that introduces a bias. So the real risk of heart attacks is higher than it might seem based on historical data."

I think that's true if we expect car accidents to become less common. E.g., now that I think about it, this may be the case in the real world over the coming decades, as self-driving cars become more common. (I now expect heart attack rates to maybe decline for other reasons, but to be pushed up by the reduced frequency of car accident deaths, such that the risk is higher than it might otherwise seem.)

But I think that the above statements aren't true if we don't expect car accidents to become less common.

So I'd want to say something like "There was a factor that reduced the risk of collapses in the past - namely, conquest pre-empting the collapse of weak states. And this factor may not hold in the present or future. This means the risk of collapse in future may be higher than one would think if one ignored this fact." 

That phrasing more accurate/clear to me than saying there's "missing data" or a bias".

Does my suggested statement still sound like it matches your idea? And does my reason for finding your phrasing strange seem reasonable to you?

Yes, that seems clearer and accurate - but I think it's clear that the types of external societies that are developing independently and are able to mount an attack, as occurred for Greece, Rome, when Ghengis Khan invaded Europe, etc. That means that in my view the key source of external pressure to topple a teetering system that does not exist now, rather than competition between peer nations. That seems a bit more like what I think of as inducing a bias, but your point is still well taken.

Yeah, I think I now understand your point, and that it updates me towards thinking collapse is now likelier than one might think, based on historical base rates, if one was ignoring this argument.

Though I'd also maybe say "There was a factor that increased the risk of collapses in the past - namely, external invasions or raids weakening states, and contributing to their collapse (not counting cases in which the states were "conquered"). And this factor is probably less likely in the present and future, as the rate of invasions and raids has declined and the world has become more unified. This means the risk of collapse in future may be lower than one would think if one ignored this fact."

And at first glance, that effect seems like it could easily be stronger than the other one.

So overall, it seems like changes with respect to "conquests, invasions, and raids" (taken together) could easily have decreased rather than increased the chance of collapse. Which made it feel a bit odd to me that you highlighted one side of that story, but not the other.

Does that make sense?

Yes, and I would include a significant discussion of this in a longer version of this post, or a paper. However, I think we mostly disagree about what people's priors or prior models were in choosing what to highlight. (I see no-one using historical records of invasions / conquered nations independent of when it contributed to a later collapse, as relevant to discussions of collapse.)

Great power wars could trigger or accelerate such a collapse, but they wouldn't lead to decoupled sociotechnical systems, or any plausible scenarios that would allow a winner to replace the loser.

What do you mean by saying "they wouldn't lead to [...] any plausible scenarios that would allow a winner to replace the loser"? E.g., if there was a war between China and the US, couldn't China replace the US as the dominant power?

FWIW, I agree with the following statement:

Because civilization is more tightly interconnected, many types of collapse would be universal, rather than local.

(Though I don't feel highly confident about whether the net effect of increased interconnectedness - and the things that go along with it - on the chance of universal collapse is positive or negative, at least when one considers other things that tend to go along with increased interconnectedness.) 

China could replace the US as a dominant power, but they wouldn't actually take over the US the way nations used to conquer and replace the culture of other countries.

And I agree that it's not obvious that interconnection on net increases fragility, but I think that it's clear, as I argued in the paper, that technology which creates the connection is fragile, and getting more so.

they wouldn't actually take over the US the way nations used to conquer and replace the culture of other countries.

I do think this is much less likely now than it was in the past.

Though at first glance, the "wouldn't" feels a bit strong. (Though I think I know much less about both geopolitics and forecasting than you do.)

Do you mean something like "Conditional on a hot war between China and the US with military actions on at least one of those countries' mainland territories (not just e.g. sea battles), and conditional on China clearly winning, the chance China would actually then administer the US as an annexed territory is <x%"? Or were you thinking about not just annexation but also a massive shift in US "culture" towards Chinese "culture"?

And roughly what x did you have in mind? E.g., 50%? 1%?

I'd be comfortable with 1% - I'd take a bet at 100:1 conditional on land warfare in China or the US with a clear victor, they winner still would at the most extreme, restore a modified modern national government controlled by citizens that had heavy restrictions on what it was allowed to do, following the post-WWII model in Japan and Germany. (I'd take the bet, but in that case, I wouldn't expect both parties to survive to collect on the bet, whichever way it ends.)

That's because the post-WWII international system is built with structures that almost entirely prevent wars of conquest, and while I don't see that system as being strong, I also don't think the weaknesses are ones leading to those norms breaking down.

But maybe, despite sticking to my earlier claim, the post-WWII replacement of Japan's emperor with a democracy is exactly the class of case we should be discussing as an example relevant to the more general question of whether civilizations are conquered rather than collapse. And the same logic would apply to Iraq, and other nations the US "helped" along the road to democracy, since they were at least occasionally - though by no means always - failing states. And Iraq was near collapse because of conflict with Iran and sanctions, not because of internal decay. (I'm less knowledgeable about the stability of Japanese culture pre-WWII.)

Interesting, thanks for the response :)