Epistemic (Spot Check?): The Fate of Rome Round 2

Introduction

Two months ago I did an epistemic spot check on Kyle Harper’s The Fate of Rome. At the time I found only a minor flaw- stating that Roman ships weren’t surpassed until the 14th century, when China did it in the 13th century. I did not consider this fatal by any other means.

Recently I decided to reread The Fate of Rome (affiliate link). This was driven by a few things. Primarily, I found myself resistant to reading more Roman history, which typically means I’m holding things in my short-term memory and will not be allowed to put new things into my brain until the existing things have been put in long term storage. But it did not hurt at all that I had just gotten access to a new exobrain, Roam, a workflowy/wiki hybrid, and yes, for purposes of this post that is an extremely unfortunate name.

This post is going to wear many hats: a second check of The Fate of Rome, a log of my work improving the epistemic spot check process, and a discussion of how Roam has affected my work. These will not be equally interesting to all people but I couldn’t write it any other way. That said, let us begin.

Process

Previously, I’d “taken notes” by highlighting passages and occasionally writing notes in the Kindle file, and then never reading them because Amazon’s anti-consumer choices made them a pain to access. Worse, I used highlights as an excuse not to take information into my brain- it was a pointer to process something later, not a reminder of something I had already processed.

When I took notes in Roam, I took notes. My initial workflow was to create a page for the book I was reading, and on it list claims from the book, each of which got their own page (I would eventually change that and leave them as bullet points on the source page). You can see the eventual result here: typically I recorded multiple claims per source-page, mostly rephrased into my own words, and always thought through instead of saved for thinking about later. (For comparison: notes from Fall of Rome round 1).

A few changes started about this time:

  • I stopped being able to read without taking notes on my laptop, meaning I could no longer use my Kindle. I don’t think I got worse at reading on Kindle, it just became obvious how bad that always was.
  • Despite having to use a multi-purpose device, I was more focused and harder to distract, probably by an order of magnitude.
  • I couldn’t work on the project passed ~9PM. I don’t think I was ever doing my best work past 9, it just became obvious in contrast to the better work I could now do.
  • I wanted to put a timestamp on every claim, so I noticed when it was unclear what time period a statement referred to.
  • “How do we know that?” questions moved from something I pushed myself to think about during second read-throughs to popping into my head unbidden. There were just natural “How do we know that?” shaped holes in my notes.
  • It became much more obvious when a bunch of paragraphs said nothing, or said nothing I valued, because even when I tried I couldn’t distill them into my notes.
  • Reading books felt like play in a way it never had before, even though it was always something I enjoyed doing.
  • I got more proactive about housecleaning. No, I wasn’t using Roam as a GTD system, it was purely research notes. And yet, I had more activation energy and more willingness to do multi-step chores. I have logs from Toggl to demonstrate this correlation, if not causation. Even assuming it’s causal I’d be shocked if it were common, so you probably shouldn’t incorporate it into your expected value of trying Roam.

At this stage the workflow is nothing I couldn’t have done in google docs, but I didn’t. I have all kinds of justifications about how knowing what I could do with Roam changed how I approached the work, but when I started that was theoretical so I’m not confident that’s what was going on. Nonetheless, I did it in Roam where I didn’t in Docs. 

So I had a Source page and a bunch of Claim pages. I started to do what I used to do in google docs or even a wordpress draft: select a claim and look for things confirming or denying it. This meant putting evidence on the Claims pages. But that didn’t feel right- why should some sources get their own page when others sat on the pages of claims from other sources? So I let claims motivate my choice of sources to look up, but every source got its own page with its claims listed on it. When I felt I knew enough I would create a Synthesis page representing what I really thought, with links to all the relevant claims (Roam lets you link to bullet points, not just pages) and a slider bar stating how firmly I believed it. This supported something I already wanted conceptually, which was shifting from [evaluating claims for truth and then judging the trustworthiness of the book] to [collating data from multiple sources of unknown reliability to inform my opinion of the world]. When this happened it became obvious Claims didn’t need their own pages and could live happily as bullet points on their associated Source page.

Once I had a Synthesis I would back-propagate a Credence to the claim that inspired the thread. Ideally I would have back propagated to all relevant claims, but that was more effort than it was worth. I put credences right in the claim so they would automatically show up when linked to, giving me a quick visual on how credible the book’s claims were when I investigated. The visual isn’t perfect because claims can have wildly different weights, but it is a start.

[Due to a bug, slider bars can be changed even by people given only read-access, so I also put the Credence in text]

Results

It turns out that The Fate of Rome was a near-ideal book about which to start asking “how do we know this?” (or maybe I’ll do more books and find out it’s average, but it definitely rewarded the behavior), because it is working with cutting edge science to prove its points, meaning it’s doing a lot of interpretation.

The Fate of Rome makes two big claims: Rome’s peak coincides with a period of unusually favorable and stable weather in the Mediterranean (from 200 BC to 150 AD), and Rome was a constant disease fest punctuated by peaks of even more illness.  What I would like to do right now is link you to my Fate of Rome Roam page, tell you to look at the links at the bottom, filter for Synthesis, and just browse through my work. It’s better prepared than I could ever do linearly, and lets you choose which parts are important to you. But I suspect there’s a learning curve to Roam so I will write things out the tedious linear way.

The Fate of Rome lists many sources of data on ancient climate. Here is a list of what I consider the 5 strongest, and the time period they supposedly applied. If you were reading this on Roam, you would have page numbers so you could verify my interpretation:

  • Cosmogenic radionuclides in ice cores say that 360BC – 690 AD had unusually stable solar activity
  • (Source unknown) says no major volcanic eruptions between “late republic” (end of the BCs) and “age of Justinian” (530s)
  • Ratio of Oxygen18 to Oxygen16 in stalagmites points to warmth during “early Imperial Rome”
  • The Tiber River flooded regularly (source unknown) during peak Imperial Rome
  • Radiocarbon-dated sediments say the Dead Sea was at a peak from 200 BC to 200 AD

I have three complaints here: he doesn’t share the resolution of each method, two of the data points are unsourced (although one points to a paper where I could have looked it up), and these time periods don’t match up particularly well. For the first: I tried to find the resolution for ice cores at a depth of 2000 years, and was unable to come to a definitive answer, but I did find a suggestion that they’re extremely sensitive to the assumptions in your model, which makes me nervous. The third thing seems even more concerning: if anything it seems like the good times should have rolled through the collapse of the western empire, not ended at 150AD like Fate suggests. When you add in the innate political nature of any claims about changing climate, I’m inclined to view Fate’s climate claims as speculative, although not impossible. 

Another question Fate raises is the baseline health of the Romans. I think Fate is correct that it was terrible, and that’s an update for me. Turns out communal baths are not a source of hygiene before chlorine. Harper claims the disease and parasite load was worse than the people on the same land before or after. I initially thought this seemed reasonable for “before” but unreasonable for “after”- medieval peasants had shockingly terrible diets and disease risks. But if anything the evidence supports the opposite of what I thought– you have to go pretty far back to find people much taller than the Romans, but height jumps just as the (western) empire falls. There are other explanations for this, around exactly which skeletons get found, but basically all the sources I found agreed that the Roman disease load was high.

I’m not without qualms though. A prime piece of evidence he uses to demonstrate a high disease load is dental caries (cavities) versus Linear Enamel Hypoplasia, a defect in the growth of a tooth. Medieval peasants had more caries than Romans but less LEH. Harper’s interpretation is that medieval peasants had worse diets than Romans (because the caries indicate high carb content) but less disease (LEH can be caused by both poor nutrition and disease, and a better diet is indicated by the lack of caries). Martin Bernstorff, a friendly medical student who I met on Roam Slack, helped me out on this one. Based on a half hour of his research, an equally plausible explanation is that medieval peasants had the same disease load but more calcium. This doesn’t mean Rome wasn’t terrible- medieval European peasants had it shockingly bad. But it is not clear cut evidence of Rome being worse.

A sub-claim is that the Antonine Plague (165AD-180AD) was caused by Smallpox. Harper is careful to say that retrospective diagnosis is difficult without biochemical evidence and there’s not actually a lot riding on this conclusion: he’s not doing epidemiological modeling dependent on properties of smallpox in particular, for example. But he does sound very confident, and I wanted to see if that was justified. Martin took a look at this one too, and concluded there was a 95% chance Harper was correct, assuming the Roman doctor’s notes were accurate. The remaining 5% covers the chance of a related pox virus with a lower mortality rate.

Overall I still like The Fate of Rome, but I have much less trust in it than I did after my first spot check, when its only sin was briefly forgetting China existed. It its fight with The Fall of Rome, it has lost ground.

 

More Process

My first try at Fate took an unrecorded number of hours to read, and ~two hours to spot check (this is shorter than usual, because of the amplification experiment) Call it < 10 hours, not counting the time to write it up. This round took 17 hours of combined reading and investigation into claims  (plus 1.5 hours of Martin’s time), and so far three hours to write it up. This isn’t an apples-to-apples comparison, but that’s not *that much* additional time, for the increase in depth and understanding I got. I credit Roam with speeding things up enormously.

Since this is partially a love letter to Roam, I want to add a few things: 

  • Over the years I’ve tried workflowy, calculist, and google docs. I did not go looking for other tools in this space and don’t intend to because I am Roam’s exact use case, so even if it’s not the best now I expect it grow towards me.
  • It’s just into beta and it shows: I probably file a bug or feature request per day. It’s never anything that renders Roam unusable, just things take longer than they should. 
  • Roam’s CEO, Conor White-Sullivan, has encouraged me to share my experience but has not given me anything for this post except a good product and the hope that it will continue to exist if enough people use it. 

 

As always, tremendous thanks to my Patreon patrons for their support. I would additionally like to thank Martin Bernstorff for his research (check out his new blog) and Edo Arad for comments on a draft.

Epistemic Spot Checks: The Fall of Rome

Introduction

Epistemic spot checks are a series in which I select claims from the first few chapters of a book and investigate them for accuracy, to determine if a book is worth my time. This month’s subject is The Fall of Rome, by Bryan Ward-Perkins, which advocates for the view that Rome fell, and it was probably a military problem.

Like August’s The Fate of Rome, this spot check was done as part of a collaboration with Parallel Forecasting and Foretold, which means that instead of resolving a claim as true or false, I give a confidence distribution of what I think I would answer if I spent 10 hours on the question (in reality I spent 10-45 minutes per question). Sometimes the claim is a question with a numerical answer, sometimes it is just a statement and I state how likely I think the statement is to be true.

This spot check is subject to the same constraints as The Fate of Rome, including:

  1. Some of my answers include research from the forecasters, not just my own.
  2. Due to our procedure for choosing questions, I didn’t investigate all the claims I would have liked to.

Claims

Claim made by the text:  “[Emperor Valerian] spent the final years of his life as a captive at the Persian Court”
Question I answered: what is the chance that is true?
My answer: I estimate a chance of (99 – 3*lognormal(0,1)) that Emperor Valerian was captured by the Persians and spent multiple years as a prisoner before dying in captivity.

You don’t even have to click on the Wikipedia page to confirm this is the common story: it’s in the google preview for “emperor valerian”. So the only question is the chance that all of history got this wrong. Wikipedia lists five primary sources, of which I verified three.  https://www.ancient-origins.net/history/what-really-happened-valerian-was-roman-emperor-humiliated-and-skinned-hands-enemy-008598 raises questions about how badly Valerian was treated, but not that he was captive.

My only qualm is the chance that this could be a lie perpetuated at the time. Maybe Valerian died and the Persians used a double, maybe something weirder happened. System 2 says the chance of this is < 10% but gut says < 15%.

 

Claim made by the text: “What had totally disappeared, however, were the good-quality, low-value items, made in bulk, and available so widely in the Roman period”
Question I answered: What is the chance mass-produced, low-value items available so widely in the Roman period, disappear in Britain by 600 AD?
My answer: I estimate a chance of (64 to 93, normal distribution) that mass-produced, low-value items were available in Britain during Roman rule and not after 600 AD.

This was one of the hardest claims to investigate, because it represents original research by Ward-Perkins. I had basically given up on answering this without a pottery PhD until google suggestions gave me the perfect article.

This is actually a compound claim by Ward-Perkins: 

  1. Roman coinage and mass-produced, low-cost, high-quality pottery disappeared from Britain and then the rest of post-Roman Europe.
  2. The state of pottery and coinage is a good proxy for the state of goods and trades as a whole, because they preserve so amazingly well and are relatively easy to date.

Data points:

    • Focuses on how amphorae were never really abundant in Britain
    • Chart stops at 400 AD
    • Graph showing large drops in amphorae distribution by 410 AD

If we believe Ward-Perkins and Brewminate, I estimate the chances that pottery massively declined at 95-99,  times 80-95 that other good declined with them. There remains the chances that the historical record is massively misleading (very unlikely with pots, although I don’t know how likely it is to have missed sites entirely), and that W-P et al are misinterpreting the record. I would be very surprised if so many sites had been missed as to invalidate this data, call it 5-15%. Gut feeling, 5-20% chance the W-P crowd are exaggerating the data, but given the absence of challenges, not higher than that and not a significant chance they’re just making shit up.

(95 to 99)*(85 to 95) * (80 to 95) = 64 to 93%

 

Claim made by the text: The Romans had mass literacy, which declined during the Dark Ages.
Question I answered: “[% population able to read at American 1st grade level during Imperial Rome] – [% population able to do same in the same geographic area in 1000 AD] = N%. What is N?”
My answer: I estimate that there is a 95% chance [Roman literacy] – [Dark Ages literacy] = (0 to 60, normal distribution) 

Data Points:

 

The highest estimate of literacy in Roman Empire I found is 30%.  Call it twice that for ability to read at a 1st grade level in cities. So the range is 5%-60%. 

The absolute lowest the European 1000AD literacy rate could be is 0; the highest estimate is 5% (and that was in the 1300s, which were probably more literate).  From the absence of graffiti I infer that even minimal literacy achievement dropped a great deal. 

Maximum = 60%-1% = 59%
Minimum = 5%-5%=0

 

Claim made by the text: “What some people describe as “the invasion of Rome by Germanic barbarians”, Walter Goffart describes as “the Romans incorporating the Germanic tribes into their citizenry and setting them up as rulers who reported to the empire.” and “Rome did fall, but only because it had voluntarily delegated its own power, not because it had been successfully invaded”.”
Question I answered: What is my confidence that this accurately represents historian Walter Goffart’s views?
My answer: I estimate that after 10 hours of research, I would be 68-92% confident this describes Goffart’s views accurately.

Data points:

  • https://blog.oup.com/2005/12/the_fall_of_rom/
    • Peter Heather: The most influential statement of this, perhaps, is Walter Goffart’s brilliant aphorism that the fall of the Western Empire was just ‘an imaginative experiment that got a little out of hand’. Goffart means that changes in Roman policy towards the barbarians led to the emergence of the successor states, dependant on barbarian military power and incorporating Roman institutions, and that the process which brought this out was not a particularly violent one.
  • https://www.goodreads.com/book/show/1680215.Barbarians_and_Romans_A_D_418_584?from_search=true 
    • Despite intermittent turbulence and destruction, much of the Roman West came under barbarian control in an orderly fashion.”
  • https://press.princeton.edu/titles/1036.html
    • Despite intermittent turbulence and destruction, much of the Roman West came under barbarian control in an orderly fashion. Goths, Burgundians, and other aliens were accommodated within the provinces without disrupting the settled population or overturning the patterns of landownership. Walter Goffart examines these arrangements and shows that they were based on the procedures of Roman taxation, rather than on those of military billeting (the so-called hospitalitas system), as has long been thought. Resident proprietors could be left in undisturbed possession of their lands because the proceeds of taxation,rather than land itself, were awarded to the barbarian troops and their leaders.”
  • https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1478-0542.2008.00523.x
    • “the barbarians and Rome, instead of being in constant conflict with each other, occupied a joined space, a single world in which both were entitled to share. What we call the barbarian invasions was primarily a drawing of foreigners into Roman service, a process sponsored, encouraged, and rewarded by Rome. Simultaneously, the Romans energetically upheld their supremacy. Many barbarian peoples were suppressed and vanished; the survivors were persuaded and learned to shoulder Roman tasks. Rome was never discredited or repudiated. The future endorsed and carried forward what the Empire stood for in religion, law, administration, literacy, and language.”
  • https://books.google.com/books/about/Rome_s_Fall_and_After.html?id=55pDIwvWnpoC “Rome’s Fall and After” indicates Goffat does believe Rome fell. But suggests its main problem was constantinople, not interactions with barbarians at all. So top percentage correct = 90%)

 

This seems pretty conclusive that Goffart thought Barbarians were accommodated rather than conquered the area (so my minimum estimate that the summary was correct must be greater than 50%). However it’s not clear how much power he thought they took, or whether rome fell at all. This could be a poor restatement, or it could be that if I read Goffart’s actual work and not just book jacket blurbs I’d agree.

 

Question I answered: Chance Elizabeth would recommend this book as a reliable source on the topic to an interested friend, if they asked tomorrow (8/31/19)?
My answer: There is a (91-99%, normal distribution) chance I would recommend this to a friend.

99% is in range, because I definitely think it’s worth reading if they’re interested in the topic. I think I’d recommend it before Fate of Rome, because it establishes that rome fell more concretely.

Is there a chance I wouldn’t recommend it?

  • They could have already read it
  • They could be more interested in disease and climate change (in which case I’d recommend Fate)
  • I could forget about it
  • I could not want to take responsibility for their reading.
  • I could be unconfident that Fall was better than what they’d find by chance.
    • This feels like the biggest one.
    • But the question doesn’t say “best book”, it just says “reliable source”
    • Only real qualm on that is that is normal history book qualms

So the minimum is 91%

 

Bonus Claims

These are the claims I didn’t check, but other people made predictions on how I would guess. Note that at this point the predictions haven’t been very accurate- whether they’re net positive depends on how you weight the questions. And Foretold is beta software that hasn’t prioritized export yet, so I’m using *shudder* screen shots. But for the sake of completeness:

Claim made by the text: The Fall of Rome: Roman Pottery pre-400AD was high quality and uniform.
Predicted answer: 29.9% to 63.5% chance this claim is correct

Claim made by the text: “In Britain new coins ceased to reach the island, except in tiny quantities, at the beginning of the fifth century”
Predicted answer: 31.6% to 94% chance this claim is correct

 

Claim made by the text: The Fall of Rome: [average German soldiers’ height] – [average Roman soldiers’ height] = N feet. What is N? .
Predicted answer: -0.107 to 0.61 ft.

 

Claim made by the text: The Romans chose to cede local control of Gaul to the Germanic tribes in the 400s, as opposed to losing them in a military conquest.
Predicted answer: 28.5% to 85.6% chance this claim is correct

 

Claim made by the text: The Germanic tribes who took over local control of Gaul in the 400s reported to the Emperor.
Predicted answer: 4.77% to 50.9% chance this claim is correct

 

Conclusion

The Fall of Rome did very well on spot-checking- no outright disagreements at all, just some uncertainties. 

On the other hand, The Fall of Rome barely mentions disease and doesn’t mention climate change at all, which my previous book, The Fate of Rome, claimed to be the main causes of the fall. The Fate of Rome did almost as well in epistemic spot checking as Fall, yet they can’t both be correct. What’s going on? I’m going to address that in a separate post, because I want to be able to link to it without forcing people to read this entire spot check.

In terms of readability, Fall starts slowly but the second half is by far the most interested I have ever been in pottery or archeology.

[Many thanks to my Patreon patrons and Parallel Forecast for financial support for this post]

Does combining epistemic spot checks and prediction markets sound super fun to you? Good news: We’re launching round three of the experiment today, with prizes of up to $65/question. The focal book will be The Unbound Prometheus, by David S. Landes, on the Industrial Revolution. The market opens today and will remain open until 10/27 (inclusive).

 

Epistemic Spot Check: The Fate of Rome (Kyle Harper)

Introduction

Epistemic spot checks are a series in which I select claims from the first few chapters of a book and investigate them for accuracy, to determine if a book is worth my time. This month’s subject is The Fate of Rome, by Kyle Harper, which advocates for the view that Rome was done in by climate change and infectious diseases (which were exacerbated by climate change).

This check is a little different than the others, because it arose from a collaboration with some folks in the forecasting space. Instead of just reading and evaluating claims myself, I took claims from the book and made them into questions on a prediction market, for which several people made predictions of what my answer would be before I gave it. In some but not all cases I read their justifications (although not numeric estimates) before making my final judgement.

I expect we’ll publish a post-mortem on that entire process at some point, but for now I just want to publish the actual spot check. Because of the forecasting crossover, this spot check will differ from those that came before in the following ways:

  1. Claims are formatted as questions answerable with a probability. If a claim lacks a question mark, the implicit question is “what is the probability this is true?”.
  2. Questions have a range of specificity, to allow us to test what kind of ambiguities we can get away with (answer: less than I used).
  3. Some of my answers include research from the forecasters, not just my own.
  4. Due to timing issues, I finished the book and a second on the topic before I did the research for spot check.
  5. Due to our procedure for choosing questions, I didn’t investigate all the claims I would have liked to.

 

Claims

Original Claim: “Very little of Roman wealth was due to new technological discoveries, as opposed to diffusion of existing tech to new places, capital accumulation, and trade.”
Question: What percentage of Rome’s gains came from technological gains, as opposed to diffusion of technical advantages, capital accumulation, and trade?

1%-30% log distribution

Data:

  • The Fall of Rome talks extensively about how trade degraded when the Romans left and how that lowered the standard of living.
  • https://brilliantmaps.com/roman-empire-gdp/ shows huge differences in GDP by region, implying there was a big opportunity to grow GDP through trade and diffusion of existing tech. That means potential growth just from catch up growth was > 50%.
  • Wikipedia doesn’t even show growth in GDP per capita (with extremely wide error bars) from 14AD to 150AD.
  • Rome did have construction and military tech (https://en.wikipedia.org/wiki/Roman_technology)
  • It also seems likely that expansion created a kind of Dutch disease, in which capable, ambitious people were drawn to fighting and/or politics, and not discovering new tech.
  • One potential place where Roman technology could have contributed greatly to the economy was lowering disease via sanitation infrastructure. According to Fate of Rome and my own research, this didn’t happen; sanitation was not end to end and therefor you had all the problems inherent in city living.

Original Claim: “The blunt force of infectious disease was, by far, the overwhelming determinant of a mortality regime that weighed heavily on Roman demography”
Question: Even during the Republic and successful periods of the empire, disease burden was very high in cities.

60%-90% normal distribution

The wide spread and lack of inclusion of 100% in the confidence interval stem from the lack of precision in the question. What distinguishes “high” from “very high”, and are we counting diseases of malnutrition or just infectious ones? I expected to knock this one out in two minutes, but ended up feeling the current estimates of disease mortality lack the necessary precision to answer it.

Data:

 

Original Claim: “The main source of population growth in the Roman Empire was not a decline in mortality but, rather, elevated levels of fertility”
Question: When Imperial Rome’s population was growing, it was due to a decline in death rates, rather than elevated fertility.

80-100%, c – log distribution

“Elizabeth, that rephrase doesn’t look much like that original claim” you might be saying quietly to yourself. You are correct- I misread the claim in the book, at least twice, and didn’t catch it until this write-up. This isn’t as bad as it seems. The claims are not quite opposite, because my rephrase was trying to explain variation in growth within Rome, and the book was trying to explain absolute levels, or possibly the difference relative to today.

Back when he was doing biology, Richard Dawkins had a great answer to the common question “how much is X due to genetics, as opposed to environment?”. He said asking that is like asking how much of a rectangle’s area is due to its length, as opposed to its width. It’s a nonsensical question. But you assign proportionate responsibility for the change in area between two rectangles.

Fate‘s original claim was much like asking how much of a trait is due to genetics. This is bad and it should feel bad, but it’s a very common mistake, and I give Fate a lot of credit for providing the underlying facts such that I could translate it into the “what causes differences between things” question without even noticing.

Since weak framing wasn’t a systemic problem in the book and it presented the underlying facts well enough for me to form my own, correct, model, I’m not docking Fate very harshly on this one.

Original Claim: “The size of Roman merchant ships was not exceeded until the 15th century, and the grain ships were not surpassed until the 19th.”
Question: “The size of Roman merchant ships was not exceeded until the 15th century, and the grain ships were not surpassed until the 19th.”

0-10% log distribution.

This is true within the Mediterranean, but if  you check Chinese ships it’s obvious it’s off by at least 100 years, possibly more.

Original Claim: too diffuse to quote.
Question: The Roman Empire suffered greatly from intense epidemics, more so than did the Republic or 700-1000 AD Europe.

90-100% c – log distribution

https://en.wikipedia.org/wiki/List_of_epidemics shows a pretty clear presence of epidemics in the relevant period and absence in the others.

 

Original Claim: too diffuse to quote.
Question: Starvation was not a big concern in Imperial Rome’s prime.

80-100% c – log distribution

https://en.wikipedia.org/wiki/List_of_famines shows Roman famine in 441 BC (the Republic) and isolated famines from 370 on, but pretty much validates that during the prime empire, mass starvation was not a threat.

Conclusion:

My fact checking found two flaws:

  1. An inaccuracy in when ships that exceeded the size of Roman trade ships were built, and/or forgetting China was a thing. The inaccuracy does not invalidate the author’s point, which is that the Romans had better shipping technology than the cultures that followed them.
  2. Bad but extremely common framing for the relative effects of disease mortality vs. birth rates.

These is well within tolerances for things a book might get wrong. I’m happy I read this book, and would read another by the same author (with perhaps more care when it refers to happenings outside of Europe), but they are not jumping to the of my list.

Is The Fate of Rome correct in its thesis that Rome was brought down by climate change and disease? I don’t know. It certainly seems plausible, but is clearly advocating for a position rather than trying to present all the relevant facts. There are obvious political implications to Fate even if it doesn’t spell them out, so I would want to read at least one of the 80 million other books on the Fall of Rome before I developed an opinion. I’m told some people think it had to do with something military, which Fate barely deigns to mention. In the future I hope to be a good enough prediction-maker to put a range on this anyways, however wide it must be, but for now I’m succumbing to the siren song of “but you could just get more data”.

[Many thanks to my Patreon patrons and Parallel Forecast for financial support for this post]

PS. This book is the first step of an ongoing experiment with epistemic spot checks and prediction markets. If you would like to participate in or support these experiments, please e-mail me at elizabeth-at-this-domain-name. The next round is planned to start Saturday August 24th.

Review: The Dueling Neurosurgeons (Sam Kean)

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I originally intended The Tale of the Dueling Neurosurgeons for epistemic spot checking, but it didn’t end up feeling necessary.  I know just enough neurobiology and psychology to recognize some of its statements as true without looking them up, and more were consistent enough with what I knew and what good science and good science writing looks like; interrogating the book didn’t seem worth the trouble.  I jumped straight to learning from it, and do not regret this choice.  The first thing I actually looked up came 20% of the way into the book, when the author claimed the facial injuries of WWI soldiers inspired the look of the Splicers from BioShock.*

[*This is true. He used the word generic mutant, not the game-specific term Splicer, but I count that under “acceptable simplifications for the masses”.  Also, he is quicker to point out that he is simplifying than any book I can remember.]

At this point it may be obvious why I think fans of this blog will really enjoy this book, beyond the fact that I enjoyed it.  It has a me-like mix of history (historical color, “how we learned this fact”, and “here’s this obviously stupid alternate explanation and why it looked just as plausible if not more so at the time”*), actual science at just the right level of depth, and fun asides like “a lot of data we’ve been talking in this chapter on phantom limbs about comes from the Civil War.  Would you like to know why there were so many lost limbs in the Civil War?  You would?  Well here’s two pages on the physics of rifles and bullets.”**

[*For example, the idea that the brain was at all differentiated was initially dismissed as phrenology 2.0.

**I’m just going to assume you want the answer: before casings were invented, rifles had a trade off between accuracy and ease of use.  Bullets that precisely fit the barrel are very hard to load, bullets smaller than the barrel can’t be aimed with any accuracy.  Some guy resolved this by creating bullets that expanded when shot.  But that required a softer metal, so when the bullet hit it splattered.  This does more damage and is much harder to remove.]

I am more and more convinced that at least through high school, teaching science independent of history of science is actively damaging, because it teaches scientific facts, and treating things as known facts damages the scientific mindset.  “Here is the Correct Thing please regurgitate it” is the opposite of science.  What I would really love to see in science classes is essentially historical reenactments.  For very young kids, give them the facts as we knew them in 18XX, a few competing explanations, and experiments with which to judge them (biased towards practical ones you know will give them informative results), but let them come to their own conclusions.  As they get older, abandon them earlier and earlier in the process; first let them create their own experiments, then their own hypotheses, and eventually their own topics.  Before you know it they’re in grad school.

The Dueling Neurosurgeons would be a terrible textbook for the lab portion of that class because school districts are really touchy about inducing brain damage.  But scientists had a lot of difficulty getting good data on the brain for the exact same reason, and Dueling Neurosurgeons is an excellent representation of that difficulty.  How do we learn when the subject is immensely complex and experiments are straightjacketed?  I also really enjoyed the exploration of  the entanglement between what we know and how we know it.  I walked away from high school science feeling those were separable, but they’re not.

You might like this book if you:

  • like the style of this blog. In particular, entertaining asides that are related to the story but not the point. (These are mostly in footnotes so if you don’t like them you can ignore them).
  • are interested in neurology or neuropsychology at a layman’s level.
  • share my fascination with history of science.
  • appreciate authors who go out of their way to call out simplifications, without drowning the text in technicalities.

You probably won’t like this book if you:

  • need to learn something specific in a hurry.
  • are squeamish about graphic descriptions of traumatic brain damage.
  • are actually hoping to see neurosurgeons duel.  That takes up like half a chapter, and by the standards of scientists arguing it’s not very impressive.

The tail end of the book is either less interesting or more familiar to me, so if you find your interest flagging it’s safe to let go.

This post supported by patreon

World War Technology

[Content Warning: both World Wars, the Holocaust]

I have a very vivid memory of reading Cryptonomicon, where a character explains that the Allies won World War 2 because they worshiped Athena (technology, strategy), and the Germans worshipped Ares (Brute Strength, physical and moral).

[Some of you may be thinking “But German craftsmanship was better, right?  It took 5/10 American tanks to take down 1 German Tank?”  I thought so too, but apparently no.  To the extent it was true, it was craftsmanship, not technology.]

The Axis did do better in encryption originally, but by the end we were reading much more of their mail than they were reading of ours.  Although it’s important to give credit to this to Polish Intelligence, who broke the Enigma code early on, enabling them to keep up as Germany increased its complexity.  If they hadn’t sent their results to Britain just as Germany invaded, Alan Turing et al. may never have been able to crack it.  That was some high leverage work there.

Anyways, I’m reading The Alchemy of Air (Thomas Hager) now, which is about the history of nitrogen chemistry, which played a much larger role in World War 1 than I would have guessed.  Fritz Haber’s invention of a way to transform atmospheric nitrogen into a usable form, something previously only accomplished by lightning and a handful of bacteria, is estimated to have prolonged the war by at least one year, possibly two. We’ll get into why in a later post.  That’s Athena.  According to the book, a lot of what the Allies wanted in reparations was not actually money, but German technology, especially chemistry.

[I do not entirely trust Hager on the relative important of chemistry and money here.  He’s spent the entire book waxing lyrical about the importance and beauty of nitrogen.  The internet was not terrible helpful; I’ve confirmed that dyes and pharmaceuticals were among goods taken as reparations, but not the amounts.  Some guy on Quora says the US, Britain, and Germany were equally competitive in technology in 1914.]

Even if Alchemy is overestimating German dominance in chemistry, I think it’s safe to say that technology was a major force behind German military power in World War 1.  And by World War 2, it wasn’t.  They made some advances and would have done worse without them, but no one ended the war thinking “man, getting access to this German technology will save us 20 years in research”.  But 60 years later, Germany is again a leader in technology, and has one of the more functional economies in the world.

This was going to be a “me wondering about a mystery” post, but once I thought about it the answer to “what changed?” is obvious.  Germany exiled or killed 25% of their scientists.  Fritz Haber, the guy who added years to the war with one invention and went on to pioneer chemical warfare?  Jewish  “Germany hurt itself while killing several million people” is not exactly news, but I think it’s important to note individual stories of how.

Although this puts me in the weird position of honoring the guy who more-or-less created chemical warfare.  But that’s maybe okay, because the same process that made Germany gun powder is also feeding half the world right now.  Utilitarian morality is complicated.