A ~monthly feature. Last month was busy for me with a lot of travel and a lot of focus on The Roots of Progress as a nonprofit organization, so I haven’t had as much time as I prefer for research and writing. Recent blog posts and news stories are generally omitted; you can find them in my links digests. All emphasis in bold in the quotes below was added by me.

Histories of technology

Finished Joel Mokyr, The Lever of Riches: Technological Creativity and Economic Progress (1990), which I mentioned last time. The first part of the book is a summary of Western technological development from ancient times through the Industrial Revolution. The second part explores the causes of that development by looking at three contrasts: classical antiquity vs. the medieval period, Europe vs. China, and Britain vs. the rest of Europe.

The book is worth a full review, for now I’ll just leave you with one insightful quote, in the chapter where Mokyr considers the analogy between technological development and biological evolution:

The study of genetics is the study of the causes of genetic variation in the population. Yet genetics has contributed little to our understanding of speciation and nothing to our understanding of extinction (Lewontin, 1974, p. 12). Economic analysis, which postulates that techniques will be chosen by profit-maximizing firms employing engineers in whose minds the genotypes of various techniques are lodged, plays a role analogous to genetics. It explains how demand and supply produce a variety of techniques, and points to the constraining influences of environment and competition as a limit to the degree of variety. Just as genetics by itself does not explain speciation, economic analysis has difficulty explaining macroinventions. Like evolution, technological progress was neither destiny nor fluke. Yet the power of Darwinian logic—natural selection imposed on blind variation—is that we need not choose between the two.

I’m now about halfway through Lynn White, Medieval Technology and Social Change (1962)—another classic. White covers three major developments: the stirrup, the use of horses as draft animals, and the development of mechanical power. The focus is on the social change that these new technologies precipitated.

Famously, White argues that the stirrup created feudalism. The stirrup allowed the rider to brace himself more firmly on his horse, which enabled a new type of mounted combat using lances that was superior to troops on foot or archers on horseback. Horses were expensive (as were armor and lances), and it required land to feed them, so land was taken away from the church and given to vassals who would, in exchange, give service to the sovereign as mounted warriors. In time, an entire culture grew up around this: these vassals became knights, with their own code of virtues (chivalry), their own training and games (tournaments), etc.

Other historians had previously traced back the development of feudalism to this new type of combat, and to Charles Martel who instigated it, but had looked for political or other social causes for the military change (one hypothesis, for instance, was that the famous battle against the Saracens at Poitiers motivated Charles to seek superior military tactics, even though he won). White’s contribution is to argue that the trigger for all of this was ultimately not social, but technological.

My only complaint so far is that White missed the chance to name this book The Stirrup in Europe.

Also on my to-read list: Friedrich Klemm, A History of Western Technology (1959), which was cited a lot by Mokyr.


In snatches of time, I am still researching agriculture for my book. Recently I’ve been reviewing historical sources on 19th-century “manures,” which today we would probably call fertilizers. It was an era when farmers were eager to find new fertilizers to improve agricultural yields, in order to meet growing demand for food from a rapidly growing population. However, agricultural chemistry was still developing, and synthetic fertilizers were decades away. Instead, farmers and scientists alike experimented with all sorts of natural fertilizers.

Both Humphry Davy, Elements of Agricultural Chemistry (1813); and Jean-Baptiste Boussingault, Rural Economy, in its Relations with Chemistry, Physics, and Meteorology (1860), have chapters on manures in which they catalog long lists of substances then in use. Dung and urine, both from animals and from humans, is of course a major feature, but it might surprise you how highly these substances were prized in the 19th century. For instance, Boussingault says:

Any expense incurred in improving this vital department of the farm, is soon repaid beyond all proportion to the outlay. The industry and the intelligence possessed by the farmer, may indeed almost be judged of at a glance by the care he bestows on his dunghill.

Later he praises Flanders for the “especial care” and “highly rational” method with which they collect human soil, which forms “the staple of an active traffic.” The Chinese, too, he notes approvingly, “collect human excrements with the greatest solicitude, vessels being placed for the purpose at regular distances along the most frequented ways.”

Fertilizers newly coming into widespread use the 19th century included oilseed cakes (formed from waste matter left over after seeds are pressed for their oil) and even bones, either broken into small pieces or ground into dust. The British demand for bones was so great, and their activities importing them from abroad so vigorous, that the German agricultural chemist Justus Liebig famously complained:

Great Britain deprives all countries of the conditions of their fertility. It has raked up the battle-fields of Leipzig, Waterloo, and the Crimea; it has consumed the bones of many generations accumulated in the catacombs of Sicily; and now annually destroys the food for a future generation of three millions and a half of people. Like a vampire it hangs on the breast of Europe, and even the world, sucking its lifeblood without any real necessity or permanent gain for itself.

(Thanks to Anton Howes for that quote)

Davy and Boussingault also suggest using as fertilizer: ashes and soot; woolen rags; shells, seaweed, mud, and slime from the sea-shore and river bottoms; refuse from the manufacture of sugar, starch, tallow, and glue; and scraps and trimmings of all types of animal remains, including hides, hair, tendons, feathers, even coagulated blood. Clearly, farmers were desperate for any source of fertility they could get.

Starting in the 1840s, another fertilizer came into use: seabird guano, mostly found on islands off the coast of Peru. James F. W. Johnston, “On Guano (1841), describes the phenomenon:

It forms irregular and limited deposits, which at times attain a depth of 50 or 60 feet (Humboldt), and are excavated like mines of iron ochre. … In the isles of Islay and Jesus 20 to 25 tons of this recent guano are occasionally collected in a single season.

This paper was published at the beginning of the guano trade, but already the end was in sight: “it does not appear, as some have been led to believe, that the supply of this substance on the cost of Peru is by any means inexhaustible.” Forty years later much of the resource was consumed, and the trade was rapidly falling off. Imported guano was ultimately replaced by synthetic fertilizer based on the Haber-Bosch process.


I attended an interesting talk on Christopher Dresser, who has been called the first industrial designer. In the 1870s or so, he was designing tea kettles, letter holders, and other objects that look as if they’re straight out of the Art Deco 1930s:

Tea pot designed by Dresser, 1879
Tea pot designed by Dresser, 1879. Wikimedia / Chris 73

This led to me perusing his book Principles of Decorative Design (1870), or at least the introduction. Dresser has a strong moralistic sense of the importance of design:

Men of the lowest degree of intelligence can dig clay, iron, or copper, or quarry stone; but these materials, if bearing the impress of mind, are ennobled and rendered valuable, and the more strongly the material is marked with this ennobling impress the more valuable it becomes.

I must qualify my last statement, for there are possible cases in which the impress of mind may degrade rather than exalt, and take from rather than enhance, the value of a material. To ennoble, the mind must be noble; if debased, it can only debase. Let the mind be refined and pure, and the more fully it impresses itself upon a material, the more lovely does the material become, for thereby it has received the impress of refinement and purity; but if the mind be debased and impure, the more does the matter to which its nature is transmitted become degraded. Let me have a simple mass of clay as a candle-holder rather than the earthen candlestick which only presents such a form as is the natural outgoing of a degraded mind.

Later, in an oft-quoted paragraph, he says:

There can be morality or immorality in art, the utterance of truth or of falsehood; and by his art the ornamentist may exalt or debase a nation.

Most of the book, though, is about the “true principles of ornamentation”:

We shall carefully consider certain general principles, which are either common to all fine arts or govern the production or arrangement of ornamental forms: then we shall notice the laws which regulate the combination of colours, and the application of colours to objects; after which we shall review our various art-manufactures, and consider art as associated with the manufacturing industries. We shall thus be led to consider furniture, earthenware, table and window glass, wall decorations, carpets, floor cloths, window-hangings, dress fabrics, works in silver and gold, hardware, and whatever is a combination of art and manufacture. I shall address myself, then, to the carpenter, the cabinet-maker, potter, glass-blower, paper-stainer, weaver and dyer, silversmith, blacksmith, gas-finisher, designer, and all who are in any way engaged in the production of art-objects.

Also on my to-read list now:


Scott Alexander reviews Njal’s Saga. (The review was an anonymous entry into Scott’s own book review contest; it received the most reader votes, but Scott graciously disqualified himself from winning his own contest.) The book is about justice in medieval Iceland, which had no police or regulators, but which did have a court. Justice in this society was often meted out via family feuds, that is, families and other coalitions often attacked and killed each other for revenge. But grievances could also be brought to court. If the court decided that, to compensate for a revenge killing, the killer should pay a fine (the weregild), maybe that could end the matter and stop the cycle of killing. In the saga, peaceful resolution often depends on the wise elder Njal; when Njal himself is killed and is no longer around to give advice, a lot of the peace unravels.

Related: by coincidence, I also came across Arnold Kling, “State, Clan, and Liberty (2013); a review of Mark Weiner’s The Rule of the Clan, which is also about medieval Iceland and its legal system. Some exerpts:

[Weiner] finds a pattern of order that he calls the rule of the clan, which does not require a strong central state. However, he shows that rule of the clan relies on a set of rules and social norms which are inconsistent with libertarian values of peace, open commerce, and individual autonomy. …

Weiner grounds his analysis in the tradition of legal historian Henry Maine, who distinguished between the Society of Status and the Society of Contract. In the former, law is oriented toward the extended family as a group. In the latter, law is oriented toward the individual.

Kling summarizes Weiner’s thesis, “from a libertarian perspective”, as:

  1. A decentralized order is possible. Indeed, it is natural for human societies to achieve such an order, rather than degenerate into the Hobbesian war of all against all.
  2. The natural decentralized order is, however, highly illiberal. It requires a set of social norms that bind the individual to the clan. Under the rule of the clan, peace is broken by feuds, commerce is crippled by the inability to put trade with strangers on a contractual basis, and individual autonomy is sacrificed for group solidarity.
  3. In the absence of a strong central state, the rule of the clan is the inevitable result. In order to graduate from the society of Status to the society of Contract, you must have a strong central state.

(Kling says he finds point 3 plausible but not fully persuasive.)

I recommend reading both pieces.


Sergey Markov, “A Future History of Biomedical Progress (2022). This made the rounds a month or two ago. It starts with a long discussion of part of the frontier of biotech tools and techniques, which you can skim or skip if you want to get to the core idea. The core idea is: we’re going to need AI to design and engineer advanced biotech, because biology is so complicated that it is intractable to create human-legible models of the entire system. Rather than learn ourselves, directly, which genes do what and what the functions of each protein are and what pathways are involved in which processes, we’ll put all of the inputs and outputs into a big ML model and have it learn.

The secondary idea in the essay is that in order to do this, we’re going to need platforms to do very high-fidelity experiments, the results of which are highly transferrable to the systems that we actually care about, such as the human body. Mouse models might not cut it; we might have to do things like grow entire human organs from stem cells in order to experiment on them and learn how they really work.

I’m far from an expert in this field, but I found these arguments plausible, particularly since the essays ties them into a broader principle, Rich Sutton’s well-known “bitter lesson” of ML: any system tailored by hand using specialized domain knowledge is eventually beaten by generic systems that learn everything from scratch, given sufficient scale in compute and training data.

I don’t think, however, that this means that humans will never understand biology. I am optimistic that AI can not only figure out the immense complexity of biological systems, but that it can also figure out how to explain it to humans.

Chris Wintersinger, “Making the proteins that living cells cannot make.” A brief description of a project being pursued by Speculative Technologies. For me, this was a glimpse into what a very ambitious biotech research project looks like. I liked this chart:

Chris Wintersinger, writing for Speculative Technologies

Brian Potter, “How the Car Came to LA:

How did we become a country where cars are the defining feature of urban life? What did that transformation look like?

Answering this question for the entire country would be an enormous undertaking. But the book Los Angeles and the Automobile, by Scott Bottles, tries to answer it for LA, one of the most car-centric cities in the US. Over a period of less than 30 years, Los Angeles was transformed from a city with streetcar and train-based transportation to one where the car reigned supreme.

Benjamin Franklin letter on lead poisoning (1786). I mentioned last time a history of lead, which pointed out that lead has been known to be toxic since antiquity. This was one of the sources it cited, a letter from Benjamin Franklin on what he knew of “the bad Effects of Lead taken inwardly”:

You will see by it, that the Opinion of this mischievous Effect from Lead, is at least above Sixty Years old; and you will observe with Concern how long a useful Truth may be known, and exist, before it is generally receiv’d and practis’d on.

Walter Benjamin, “On the Concept of History (1940). I was disappointed with this, but it does contain this remarkable quote (I’ll take the translation from a different source):

A Klee painting named Angelus Novus shows an angel looking as though he is about to move away from something he is fixedly contemplating. His eyes are staring, his mouth is open, his wings are spread. This is how one pictures the angel of history. His face is turned toward the past. Where we perceive a chain of events, he sees one single catastrophe which keeps piling wreckage upon wreckage and hurls it in front of his feet. The angel would like to stay, awaken the dead, and make whole what has been smashed. But a storm is blowing from Paradise; it has got caught in his wings with such violence that the angel can no longer close them. The storm irresistibly propels him into the future to which his back is turned, while the pile of debris before him grows skyward. This storm is what we call progress.

(After that vivid description, incidentally, I found the actual painting quite underwhelming)

Milton Friedman, “How to Cure Health Care (2001):

Since the end of World War II, the provision of medical care in the United States and other advanced countries has displayed three major features: first, rapid advances in the science of medicine; second, large increases in spending, both in terms of inflation-adjusted dollars per person and the fraction of national income spent on medical care; and third, rising dissatisfaction with the delivery of medical care, on the part of both consumers of medical care and physicians and other suppliers of medical care.

Thanks to Roots of Progress fellow Tina Marsh Dalton for the link.

Scott Aaronson, “The Kolmogorov option (2017). It’s important to speak the truth, even when the truth is unpopular—but it’s not worth martyring yourself for no purpose, if the Powers that Be punish truth-tellers. The Kolmogorov option (named after the Russian mathematician who exemplified it) is to choose your battles and bide your time until Power weakens and the truth-tellers can launch a coordinated attack. In response is Scott Alexander, “Kolmogorov Complicity And The Parable Of Lightning (2017). The Kolmogorov option can work, but it’s difficult to pull off:

Kolmogorov’s curse is to watch slowly from his bubble as everyone less savvy than he is gets destroyed. The smartest and most honest will be destroyed first. Then any institution that reliably produces intellect or honesty. Then any philosophy that allows such institutions. … Then he and all the other savvy people can try to pick up the pieces as best they can, mourn their comrades, and watch the same thing happen all over again in the next generation.

The “parable of lightning” is an excellent illustration of how if a society insists on even a seemly tiny, insignificant lie, it will eventually spread to infect the entire society and to destroy all truth-seeking people and organizations. Recommended.

Scott Alexander, “Paradigms All The Way Down (2019). (Scott is my favorite blogger, so I make no apologies for him appearing here three times.) Several epistemic paradigms are in broad strokes isomorphic; perhaps they are all saying the same thing about the relationship of theories and evidence?


Ian Tregillis, The Alchemy Wars trilogy. I mentioned this last time when I had finished approximately the first book; now I’m well into the third. I hesitate to recommend any fiction too strongly before I’ve finished it, but so far I’m this is some of the best stuff I’ve read in a while.

Other items on my to-read list

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The study of genetics is the study of the causes of genetic variation in the population. Yet genetics has contributed little to our understanding of speciation and nothing to our understanding of extinction (Lewontin, 1974, p. 12).

My understanding is that genetics has in fact contributed enormously to our understanding of speciation and also extinction - and here's a book-length treatment I found from 1977, which post-dates Mokyr's cite but not his book. Fortunately I think the point about macroinventions doesn't actually rest on this analogy.

In the saga, peaceful resolution often depends on the wise elder Njal; when Njal himself is killed and is no longer around to give advice, a lot of the peace unravels.

An important caveat is that even when the trial erupted into bloodshed, no one suggested they would refuse to pay weregilds. They did not rebel against the law itself. That this legal system persisted for centuries is fascinating.