The Most Intolerant Wins

August 31st, 2016

Nassim Nicholas Taleb explains how a certain type of intransigent minority can make the entire population adopt their preferences — while a naive observer would be under the impression that the choices and preferences are those of the majority:

This example of complexity hit me, ironically, as I was attending the New England Complex Systems institute summer barbecue. As the hosts were setting up the table and unpacking the drinks, a friend who was observant and only ate Kosher dropped by to say hello. I offered him a glass of that type of yellow sugared water with citric acid people sometimes call lemonade, almost certain that he would reject it owing to his dietary laws. He didn’t. He drank the liquid called lemonade, and another Kosher person commented: “liquids around here are Kosher”. We looked at the carton container. There was a fine print: a tiny symbol, a U inside a circle, indicating that it was Kosher. The symbol will be detected by those who need to know and look for the minuscule print. As to others, like myself, I had been speaking prose all these years without knowing, drinking Kosher liquids without knowing they were Kosher liquids.

A strange idea hit me. The Kosher population represents less than three tenth of a percent of the residents of the United States. Yet, it appears that almost all drinks are Kosher. Why? Simply because going full Kosher allows the producer, grocer, restaurant, to not have to distinguish between Kosher and nonkosher for liquids, with special markers, separate aisles, separate inventories, different stocking sub-facilities. And the simple rule that changes the total is as follows:

A Kosher (or halal) eater will never eat nonkosher (or nonhalal) food , but a nonkosher eater isn’t banned from eating kosher.

Let us call such minority an intransigent group, and the majority a flexible one. And the rule is an asymmetry in choices.

I once pulled a prank on a friend. Years ago when Big Tobacco were hiding and repressing the evidence of harm from secondary smoking, New York had smoking and nonsmoking sections in restaurants (even airplanes had, absurdly, a smoking section). I once went to lunch with a friend visiting from Europe: the restaurant only had availability in the smoking sections. I convinced the friend that we needed to buy cigarettes as we had to smoke in the smoking section. He complied.

Two more things. First, the geography of the terrain, that is, the spatial structure, matters a bit; it makes a big difference whether the intransigents are in their own district or are mixed with the rest of the population. If the people following the minority rule lived in Ghettos, with their separate small economy, then the minority rule would not apply. But, when a population has an even spatial distribution, say the ratio of such a minority in a neighborhood is the same as that in the village, that in the village is the same as in the county, that in the county is the same as that in state, and that in the sate is the same as nationwide, then the (flexible) majority will have to submit to the minority rule. Second, the cost structure matters quite a bit. It happens in our first example that making lemonade compliant with Kosher laws doesn’t change the price by much, not enough to justify inventories. But if the manufacturing of Kosher lemonade cost substantially more, then the rule will be weakened in some nonlinear proportion to the difference in costs. If it cost ten times as much to make Kosher food, then the minority rule will not apply, except perhaps in some very rich neighborhoods.

Stop trouble before it starts

August 30th, 2016

Riots might not begin at all if authorities could overwhelm “action nodes” as they developed:

Experience has shown that the National Guard is not well adapted to the mission of early containment of a riot. It takes the Guard several days to get into action because when it is called, it is not merely foot soldiers that are summoned but their entire apparatus of logistics and command that must be mobilized as well. Moreover even the hint that authorities are thinking about calling out the National Guard could be seen as a provocative acknowledgement of a riot’s incipiency. Public appeals that the Guard be summoned may therefore amount to a sort of focal incident and do almost as much to choreograph the beginning of a riot as to deter its occurrence. Of course once it gets into action the Guard does seem to pacify full-blown riots fairly swiftly. This fact suggests that sheer numbers of anti-riot personnel may be more important than tactics, training or other variables in quietening civil unrest.

For this reason cities might well consider the benefits of using a civilian auxiliary to reinforce and supplement the police force. Such a force could be deployed rapidly and demobilized just as fast once the trouble had died down because its command infrastructure, that of the municipal police, is always up and running. Of course it is out of the question for police departments permanently to maintain as many full-time officers as might be required by peak load demand. An analogy might be drawn to volunteer fire fighters, who receive training, though far less than their full-time professional counterparts, to enable them to meet contingencies too remote to justify commissioning full-time personnel. The original idea of the militia, as envisioned by the drafters of the United States Constitution, reflected something of the notion that ordinary citizens bore the final responsibility for the security of the communities in which they lived (Dowlut 1983: 93). When not burdened with a command and control superstructure but simply used to supplement law enforcement resources already in place, a modem equivalent to the militia might well serve to stop trouble before it started.

Passive-Aggressive Gringo Repellent

August 30th, 2016

Mexicans like keeping Mexico Mexican, Steve Sailer suggests:

“Nothing ever happens in Mexico until it happens,” said (maybe) dictator Porfirio Diaz.

You are often told that if you look at a map, you can see that it’s a law of nature that the United States of America must fill up with Mexicans. You almost never hear anybody suggest that the map implies that Mexico must fill up with Americans, which would seem more likely a priori.

How do the Mexicans keep the gringos from inundating Mexico? Some of its by law, some of its by violent lawlessness, but a lot is by a sort of passive-aggressive cruddiness: nobody is too sure who owns what land, the streets are dangerous to cross if you aren’t young and nimble, the hospitals are kind of inept, and so forth and so on.

Former foreign secretary Jorge Castaneda suggested that if Mexico were to try to make the country more appealing to American retirees, they’d find they had made the country better for Mexicans. But that idea hasn’t proven popular.

Brutality can terminate riots promptly

August 29th, 2016

Once it gets started, rioting is difficult to stop by authorities as constrained as American police forces are:

Of course authorities prepared to resort to brutality can terminate riots promptly. Buford gives the example of how the Sardinian police militia smothered a soccer riot during the 1990 World Cup matches. Hundreds of rowdy English soccer fans had flown in on chartered planes, and were determined to find trouble. The police did not try to cover every action node at once; this would have left them outnumbered everywhere. Instead, following textbook military strategy, they massed forces and surrounded first one, then another group of hooligans inglisi, rendering each in turn hors de combat by beating them senseless with truncheons. Few of the Englishmen actually had to be arrested (which would have been very time-consuming for the police). Nevertheless, because they were not allowed to innocently transpire through police lines to re-appear at some less well-defended action node, the riot soon collapsed.

The Japanese Zoning System

August 29th, 2016

Alex Tabarrok explains the Japanese zoning system:

Japan has 12 basic zones, far fewer than is typical in an American city. The zones can be ordered in terms of nuisance or potential externality from low-rise residential to high-rise residential to commercial zone on through to light industrial and industrial. But, and this is key, in the US zones tend to be exclusive but in Japan the zones limit the maximum nuisance in a zone. So, for example, a factory can’t be built in a residential neighborhood but housing can be built in a light industrial zone.

[...]

In addition, residential means residential without discrimination as to the type or form of resident.

On that last point, one commenter notes that the Japanese do not have to worry about crime, and Steve Sailer added that “Americans have replaced discrimination by race with discrimination by cost, which works pretty well, but, of course, it’s very expensive.”

Bureaucratic Comedy

August 28th, 2016

The real divide in politics pits the people who think government looks like The West Wing against the people who think it looks like Yes, Minister:

The soaring principles of The West Wing did sometimes turn up in Yes, Minister (and its sequel, Yes, Prime Minister), but by the end of each half-hour they had usually been buried in a committee or snuffed out in a seedy bargain. The result may not have been an inspiring vision of good government, but it was one of the wittiest TV shows of the 1980s; this week, sadly, saw the death of Antony Jay, the British broadcaster who co-created and co-wrote it.

Jay was a man of the right; his writing partner, Jonathan Lynn, hailed from the left. They nonetheless worked well together, perhaps because the specific policies that popped up on their two shows barely mattered.

[...]

The setup was simple: A somewhat well-meaning but basically spineless politician takes command of the Department of Administrative Affairs, and the department does everything it can to keep him from changing anything. (Yes, Prime Minister kept the basic formula in place, but now he had the entire British government to deal with.) Early in the first show’s run, the viewer is primed to sympathize with the minister and to cheer his occasional reformist victories, but with time he comes to represent a different sort of social malady—a man willing to do virtually anything for votes and publicity, just as the bureaucrats he locks horns with are willing to do virtually anything to maintain the status quo. The two shows’ 38 episodes, which ran from 1980 to 1988, sometimes feel like a public-choice textbook in sitcom form, with characters happy to spell out the venal rationales for everything they do.

The Idea of Improvement

August 28th, 2016

What caused innovation to accelerate in so many different industries during the British Industrial Revolution? Anton Howes suggests the emergence of an idea that was even simpler and more fundamental than systematic experimentation or Newtonian mechanics, though it was implicit to each of them — the idea of improvement itself:

I present new evidence on the sources of inspiration and innovation-sharing habits of 677 people who innovated in Britain between 1651 and 1851. The vast majority of these people — at least 80% — had some kind of contact with innovators before they themselves started to innovate. These connections were not always between members of the same industry, and innovators could improve areas in which they lacked expertise. This suggests the spread, not of particular skills or knowledge, but of an improving mentality. The persistent failure to implement some innovations for centuries before the Industrial Revolution, despite the availability of sufficient materials, knowledge, and demand, further suggests that prior societies may have failed to innovate quite simply because the improving mentality was absent. As to what made Britain special, we cannot know for sure without constructing similarly exhaustive lists of innovators for other societies. But a likely candidate is that the vast majority of innovators — at least 83% — shared innovation in some way, while only 12% tried to stifle it. Just like a religion or a political ideology, the improving mentality spread from person to person, and to be successful required effective preachers and proselytisers too.

Schelling Incidents and Schelling Points

August 27th, 2016

Any of several major intersections, parks, or schoolyards may have seemed the natural place for a large number of riot-disposed people to gather following the acquittals in People v. Powell (the original Rodney King beating case) — which amounted to a Schelling incident, at least in part because it had been advertised as such for weeks by TV and newspaper accounts of the trial:

One can hardly doubt that many residents of South-Central bent on making trouble arrived at places they expected to be “focal” only to find them largely deserted. But Schelling’s work implies that a substantial number of others would have guessed right — would have gone to a major intersection, Korean strip-mall parking lot, or other public space and found the crowd they had expected to find nearing its critical mass — waiting for some of the outliers from non-viable focal points to find their way to more promising locations.

But here is a problem. Those who selected a non-viable focal point — in other words, those who guessed wrong — would now have to find out where everyone else went in order to join them. How did they get this information? Los Angeles’ television stations’ aggressive news coverage of the disturbance from its very beginning seems to have played a key role. Within minutes after the verdicts were announced in Powell, minicam crews were doing news “live from the scene,” letting everyone in town know where the trouble was. Innocents thus learned what neighborhoods to avoid; but non-innocents, who wanted to take part in the looting, also found out where to go.

Although inadvertently, the stations lowered the search costs for aspiring rioters. Without TV, other techniques would surely have been used by people hying to find out where to go in order to loot and burn with little fear of arrest. But the broadcast media are by far the best way to get accurate information to many people at once. Especially in spread-out places like Los Angeles, rioting would be less likely to occur if information about the location of viable focal points were harder to come by.

Inadvertently.

What Reality are Trump People Living In?

August 27th, 2016

What reality are Trump people living in?, Jer Clifton wonders aloud:

As luck would have it, I happen to be a researcher at Penn who studies the impact of primal world beliefs, which are beliefs about the nature of reality writ large such as “the world is fascinating.”

[...]

So I had this fantastic theory that Republicans would see the world as way more dangerous than Democrats. I though that might explain Republicans’ “irrational” a) fear of criminals which manifests as interest in law and order and support for mandatory minimums, c) fear of ISIS, d) fear of Mexicans, e) fear of people coming to take their guns, f) fear of government, and g) fear of out-group members generally. At their last convention, and indeed for every single Republican debate, it seemed like candidates were always trying to out-terrorize each other (“No, I understand the great peril we are in!”…”No, no. I understand it better.”)

However, this theory was wrong. Republicans see the world as slightly more dangerous, but it’s very slight.

[...]

Let’s talk about the biggest differences, because they both make sense and don’t make sense: first hierarchical and second just.

The “hierarchical” primal concerns the nature of differences. Namely, does difference imply that something is better or worse? For those who believe that reality is hierarchical, if two things are different that tends to (not always) imply that one is better than the other. Likewise, for those who see reality as nonhierarchical, differences are likely surface and meaningless distinctions and probably distractions. Under the latter view, any attempt to organize the world into “better” or “worse” things will either fail or be inaccurate and superficial. However, for folks who see the world as hierarchical, most things can be fairly usefully ranked and ordered from better or worse. This includes objects, from knives to countries, and people, from individuals to ethnic groups. The biggest difference between Republicans and Democrats is that Republicans on average see the world as more hierarchical, or, to put it a different way, Democrats gloss over differences.

It makes sense, therefore, that the second biggest distinction between Republicans and Democrats concerns whether or not the arc of life trends towards justice. Does life find a way to reward those who do good and punish those who do bad? Is the world a place where working hard and being nice pays off? With plenty of exceptions, Republicans tend to say ‘Yes’ and Democrats say ‘No.’

[...]

Trump supporters out-Republican their Republican peers by seeing the world as even more hierarchical and just.

What does this all mean?

Those who see the world as hierarchical and just will tend to assume in small ways that successful people are better people. This might help explain infatuations with billionaires generally.

If we assume that the world is hierarchical and just, then political correctness appears foolish. PC culture is a real problem because it glosses over differences that really matter. This might explain a deep frustration on the Right about political correctness that the Left just doesn’t get.

I’ve often been confused by why Americans need to talk about their country like it’s the best country in the history of the world. But, if we assume that the world is hierarchical and just, and America is the most powerful country in the world, then it stands to reason that America is also the best. It would feel false to say, “America is unique” without also saying, “America is the best.”

Finally, if we assume that the world is hierarchical and just, then we will have more difficulty mixing with and including out-groups. Obviously, hispanic or African American culture is different than the culture of small-town white America where, according to Haidt, sanctity concerns matter more.

Gnon rewards those who follow His laws.

Understanding Riots

August 26th, 2016

David D. Haddock and Daniel D. Poisby wrote Understanding Riots after a previous breakdown in law and order:

After the Los Angeles riot in spring of 1992, almost every pundit in the country took a turn at explaining why riots occur. The conventional wisdom on the subject went something like this: certain dramatic events such as political assassinations or unpopular jury verdicts crystalize riots from social rage. So to understand riots, one must understand the causes of social rage, usually said to be racism, poverty, lack of economic opportunity, and why people who experience this rage manage it in such a destructive manner. The usual suspects include breakdown of the family, television, and a generalized cultural disorientation.

All of these explanations have some truth in them, but are evidently incomplete. First, they explain too much. The predisposing social conditions are with us all the time, yet riots are episodic. Second, they explain too little. Many mob actions, like European soccer riots or the increasingly predictable civil meltdowns in the home cities of National Basketball Association champions, are triggered by good news, and not obviously related to social injustice or existential anomie. Indeed, during the Los Angeles riots, anyone with a TV set could see that jubilation rather than fury best characterized the mood of the people in the streets. It is hard to credit that these exhilarated looters with their new VCR’s and cameras were protesting the juiy system, the state of race relations in Southern California, or anything else. They were, in fact, having a party. Moreover, many of those who risked life and limb opposing the more outrageous excesses of the rioters were themselves poor, unemployed, and victims of racism.

Conversely, a crowd is not an incipient riot merely because it assembles a great many people with the predisposing demographic characteristics. For example, every Fourth of July in Chicago’s Grant Park there is a fireworks display that usually attracts about a million spectators. In certain parts of the grounds, people are packed together like sardines, so that individuals substantially lose their ability to decide where to go. One goes where the crowd goes. Going against it is impossible, and even leaving it (unless one is near the edge) may be difficult. Some people dislike the experience, but whatever its discomforts, the Fourth of July crowd at Grant Park is not a riot in the making. The crowd is big, it is loud, it is unmanageable, it is filled with people who have suffered from racial discrimination and economic deprivation, it has, in aggregate, drunk a lot of beer (which is legally for sale at dozens of kiosks at the event); but it is only a crowd, not an incipient riot.

Day in and day out in any big city, police blotters will reflect the existence of a fairly steady background supply of theft, mugging, arson, and homicide. But this jumble of criminal mischief does not amount to a “riot”; riots are the coordinated acts of many people. If they are coordinated, who coordinates them? Authorities looking for ways to explain why trouble has broken out on their watch sometimes ascribe exaggerated organizational. powers to “outside agitators.” While, as we explain, there is definitely a leadership niche in the ecology of a mob, it seems to become important only after the crowd has assembled. Riots are not, as a rule, plotted and scripted affairs.

Calculating Folk

August 26th, 2016

The dwarves of modern fantasy stories tend to be associated with Norse culture, but the dwarves of Tolkien’s Middle Earth were inspired by another ethnic group:

We have, then, a bunch of short, bearded beings exiled from their homeland, who have dreamed forever of returning. They are linked to a place they lost long ago, dwell in other realms throughout the earth, and yet are so profoundly connected to their own kingdom that it remains vivid to them while for others it is a fading memory. There is one tribe that offers a perfect real-world parallel to Tolkien’s dwarves; there is only one nation that has remained existentially linked to the kingdom its people lost long ago even as it mingled among kings and queens and common folk of other lands throughout history: the Jews. In a reflection on Tolkein and the Jews, to which this essay is indebted, Rabbi Jeffrey Saks notes that the dwarves’  “sorrowful song of longing to return to their homeland might have been lifted from a Middle Earth Kinnot Tisha B’Av” — a reference to the lamentations read by Jews when they mourn the destruction of Jerusalem.

The dwarves of Middle Earth, the central characters of one of the most beloved books of all time, are indeed based on the Jews. This was confirmed by Tolkien himself in a 1971 interview on the BBC: “The dwarves of course are quite obviously, [sic] couldn’t you say that in many ways they remind you of the Jews?” he asked. “Their words are Semitic obviously, constructed to be Semitic.” Similarly, in a letter to his daughter, Tolkien reflected, “I do think of the ‘Dwarves’ like Jews: at once native and alien in their habitations, speaking the languages of the country, but with an accent due to their own private tongue.”

This passage from The Hobbit takes on a different tone once you see the parallels:

The most that can be said for the dwarves is this: they intended to pay Bilbo really handsomely for his services; they had brought him to do a nasty job for them, and they did not mind the poor little fellow doing it if he would; but they would all have done their best to get him out of trouble, if he got into it….?There it is: dwarves are not heroes, but calculating folk with a great idea of the value of money; some are tricky and treacherous and pretty bad lots; some are not, but are decent enough people like Thorin and company, if you don’t expect too much.

Tolkien himself was no anti-Semite though. Here’s his response to a German publisher inquiring into his racial background before taking on The Hobbit:

I am not of Aryan extraction: that is Indo-Iranian; as far as I am aware none of my ancestors spoke Hindustani, Persian, Gypsy, or any related dialects. But if I am to understand that you are enquiring whether I am of Jewish origin, I can only reply that I regret that I appear to have no ancestors of that gifted people. My great-great-grandfather came to England in the 18th century from Germany: the main part of my descent is therefore purely English, and I am an English subject — which should be sufficient. I have been accustomed, nonetheless, to regard my German name with pride, and continued to do so throughout the period of the late regrettable war, in which I served in the English army. I cannot, however, forbear to comment that if impertinent irrelevant inquiries of this sort are to become the rule in matters of literature, then the time is not far distant when a German name will no longer be a source of pride.

Lidar on a Chip

August 25th, 2016

MIT’s Photonic Microsystems Group has developed lidar on a chip, with no moving parts:

Most lidar systems—like the ones commonly seen on autonomous vehicles—use discrete free-space optical components like lasers, lenses, and external receivers. In order to have a useful field of view, this laser/receiver module is mechanically spun around, often while being oscillated up and down. This mechanical apparatus limits the scan rate of the lidar system while increasing both size and complexity, leading to concerns about long-term reliability, especially in harsh environments. Today, commercially available high-end lidar systems can range from $1,000 to upwards of $70,000, which can limit their applications where cost must be minimized.

[...]

Our lidar chips are produced on 300-millimeter wafers, making their potential production cost on the order of $10 each at production volumes of millions of units per year. These on-chip devices promise to be orders of magnitude smaller, lighter, and cheaper than lidar systems available on the market today. They also have the potential to be much more robust because of the lack of moving parts. The non-mechanical beam steering in this device is 1,000 times faster than what is currently achieved in mechanical lidar systems, and potentially allows for an even faster image scan rate. This can be useful for accurately tracking small high-speed objects that are only in the lidar’s field of view for a short amount of time, which could be important for obstacle avoidance for high-speed UAVs.

[...]

Our device is a 0.5 mm x 6 mm silicon photonic chip with steerable transmitting and receiving phased arrays and on-chip germanium photodetectors. The laser itself is not part of these particular chips, but our group and others have demonstrated on-chip lasers that can be integrated in the future. In order to steer the laser beam to detect objects across the LIDAR’s entire field of view, the phase of each antenna must be controlled. In this device iteration, thermal phase shifters directly heat the waveguides through which the laser propagates. The index of refraction of silicon depends on its temperature, which changes the speed and phase of the light that passes through it. As the laser passes through the waveguide, it encounters a notch fabricated in the silicon, which acts as an antenna, scattering the light out of the waveguide and into free space. Each antenna has its own emission pattern, and where all of the emission patterns constructively interfere, a focused beam is created without a need for lenses.

Primordial Pressure Cooker

August 25th, 2016

For nearly a century, the origin of life has been traced back to a “primordial soup“:

Under the conventional theory, life supposedly began when lightning or UV rays caused simple molecules to join together into more complex compounds. This culminated in the creation of information-storing molecules similar to our own DNA, housed within the protective bubbles of primitive cells. Laboratory experiments confirm that trace amounts of molecular building blocks that make up proteins and information-storing molecules can indeed be created under these conditions. For many, the primordial soup has become the most plausible environment for the origin of first living cells.

But life isn’t just about replicating information stored within DNA. All living things have to reproduce in order to survive, but replicating the DNA, assembling new proteins and building cells from scratch require tremendous amounts of energy.

[...]

This process works a bit like a hydroelectric dam. Instead of directly powering their core metabolic reactions, cells use energy from food to pump protons (positively charged hydrogen atoms) into a reservoir behind a biological membrane. This creates what is known as a “concentration gradient” with a higher concentration of protons on one side of the membrane than other. The protons then flow back through molecular turbines embedded within the membrane, like water flowing through a dam. This generates high-energy compounds that are then used to power the rest of cell’s activities.

Life could have evolved to exploit any of the countless energy sources available on Earth, from heat or electrical discharges to naturally radioactive ores. Instead, all life forms are driven by proton concentration differences across cells’ membranes. This suggests that the earliest living cells harvested energy in a similar way and that life itself arose in an environment in which proton gradients were the most accessible power source.

Recent studies based on sets of genes that were likely to have been present within the first living cells trace the origin of life back to deep-sea hydrothermal vents. These are porous geological structures produced by chemical reactions between solid rock and water. Alkaline fluids from the Earth’s crust flow up the vent towards the more acidic ocean water, creating natural proton concentration differences remarkably similar to those powering all living cells.

The studies suggest that in the earliest stages of life’s evolution, chemical reactions in primitive cells were likely driven by these non-biological proton gradients. Cells then later learned how to produce their own gradients and escaped the vents to colonise the rest of the ocean and eventually the planet.

Why Do Democracies get Weaker & more Parasitic?

August 24th, 2016

Why do democracies get weaker & more parasitic?

What you have under a representative, egalitarian, winner take all, democracy is a shifting coalition of about 51% of voters aligned to threaten about 49%.

If you’re getting more than 51% of the vote (which is certainly possible) that just means you’re leaving rents on the table. You could take more, and/or give less, and still win the election.

Additionally, maximum rent extraction occurs if your coalition comprises the cheapest 51% of voters, in other words, the most useless and parasitic.

In relative terms, the 51% will tend to expand in number as they gorge on the 49%, who will tend to diminish. That means, the 51% will generally be in the position of being able to kick their most productive members out into the 49% and begin consuming them turn, getting ever more radically leftist, degenerate, and freeloading in the process as the polity becomes progressively weaker and more parasitic, until finally, it collapses.

This is one explanation for the expressions “Cthulu only swims left” or “the ratchet effect.”

Thankfully, there are alternatives to democracy.

Why did the Roman Economy Decline?

August 24th, 2016

Peter Brown of Princeton University is one of Mark Koyama’s favorite historians of late antiquity, but Koyama doesn’t agree with Brown’s explanation for why the Roman economy declined:

In The Rise of Western Christendom, Brown summarizes the new wisdom on the transition from late antiquity to the early middle ages. He accepts that this transition brought about an economic decline — a decline evident in the radical simplification in economic life that took place. Long distance trade contracted. Cities shrank and emptied out. The division of labor became less complex. Many professions common in the Roman world disappeared.

All of this is relatively uncontroversial. At issue is what caused this decline? Traditional accounts emphasized the destruction brought about by barbarian invasions and civil wars as the frontiers of the Western Empire collapsed. These accounts emphasized a collapse in trade and increased economic insecurity. Brown, however, argues that the bulk of modern research rejects this old fashioned view.

[...]

The barbarian invasions, of course, play a role in this story because they put pressure on the Roman state. But their role is peripheral. Rather, Brown contends that the Roman state was the engine of economic growth of late antiquity. Turning on its head the old view associated with Michael Rostovtzeff that attributed the decline of the Roman economy to high taxes imposed by the Emperor Diocletian and his successors, Brown argues that these high taxes were in fact the source of economic dynamism.

[...]

The collapse of the Roman state was catastrophic, not because the Roman state was an engine of economic growth, as Brown contends, but because it provided, albeit imperfectly, the public good of defense. In the absence of this, transactions costs greatly increased, long-distance trade declined, markets contracted, and urbanization declined.

The notion of a Malthusian Trap helps explain how high taxes — especially efficient land taxes — might help, rather than hurt, per capita income.