J. Bradford DeLong's Blog, page 433

Should-Read: Lant Pritchett: The Perils of Partial Attrib...

Should-Read: Lant Pritchett: The Perils of Partial Attribution: Let���s All Play for Team Development: "There was a growth acceleration in 1993 that created 1.1 trillion in additional GDP...

...Then, there was another growth acceleration in 2002 that created another 2.5 trillion in GDP (over and above the previous). Together, relative to the ���business as usual��� trajectory there has been 3.6 trillion dollars in gain (this cumulative additional GDP is larger than the annual total of the UK or France of about 2.8 trillion).

What caused this additional gain? Of course, no one is really sure exactly what it was and how to parse out the factors and simplistic (e.g. ���trade reform���) explanations are almost certainly, well, simplistic. But something did happen and it almost certainly had to do with deft handling of the macro-economy plus a well-executed shift in strategy towards greater reliance on markets and more openness to the global economy (which is not saying that ���laissez faire��� was the answer or that India turned into a ���neo-liberal��� state).

Who caused this additional gain? In order to achieve a national policy shift there were of course hundreds, if not thousands of people who participated in producing evidence, disputing explanations of India���s past growth, examining alternatives for the future. But let me single out one group. The ICRIER (India Council on Research on International Economic Relations) was a think tank founded in 1981 that, according to its 20th anniversary document:

The Indian Council for Research on International Economic Relations (ICRIER) was established in August 1981 as an autonomous, policy-oriented, not-for-profit, research institution. This initiative was intended to foster improved understanding of policy choices for India in an era of growing international economic integration and interdependence....

There is a narrative in which Ford Foundation, a global philanthropy provides some millions of dollars of funding that play some role in creating a think tank that itself then plays some role in providing the conditions in which good policy choices are made that then results in the creation of 3.6 trillion in additional output of Indians. Suppose the Ford Foundation gave 36 million dollars (I have no idea what it really was but I strongly suspect this was the right order of magnitude and I just make it divisible) to support ICRIER....

In a very strange turn of events the organizations and supporters of the wildly successful ���team development��� are under pressure to sacrifice actions that can produce trillions in gains (in the economy, in education, in health, etc.) through systemic transformation. Instead development actors are being pressured to do only actions for which ���rigorous evidence��� proves ���what works��� but that leads inevitably to a focus on individualized actions known to produce at best mere millions���but for which the donors and external development actors can take direct causal credit. But there are real dangers from the perils of partial attribution in which individual actors care more about what they can take credit for than whether there is team success.

Should-Read: Equitable Growth: Jobs Day Graphs: October 2...

Should-Read: Equitable Growth: Jobs Day Graphs: October 2017 Report Edition: "After an increase in September, the prime employment rate fell slightly to 78.8 percent in October...

...Even with an unemployment rate just above 4 percent, the labor market won���t be at full employment until the employment rate further strengthens...

Should-Read: Matteo Maggiori, Brent Neiman, and Jesse Sch...

Should-Read: Matteo Maggiori, Brent Neiman, and Jesse Schreger: International Currencies and Capital Allocation: "The external wealth of countries has increased dramatically over the last forty years...

...Much is still unknown about trillions of dollars of capital allocated across the globe. Using a novel security-level dataset covering more than $27 trillion of global securities portfolios we find that the structure of global portfolios is driven, at both the macro and micro level, by an often neglected aspect: the currency of denomination of the assets. If a bond is denominated in the currency of one particular country, then investors based in that country tend to own the vast majority of that bond. This implies that the much-studied home bias in bonds is instead mostly currency bias.

Foreigners' portfolios are very different from domestic portfolios: foreigners only finance a subset of domestic firms, those that issue bonds in the foreigners' currency. The dollar and the euro are exceptions to this pattern, with companies in the US and EMU uniquely able to place local currency bonds in foreign portfolios. We uncover a large and pervasive shift in the use of these international currencies starting around the 2008 financial crisis. Cross-border portfolio holdings have starkly shifted away from euro-denominated bonds and toward dollar-denominated bonds...

The Robot Uprising Is Near: Berkeley's Blum Center Buil...

The Robot Uprising Is Near: Berkeley's Blum Center Building wants me to pay with Apple Pay in order for me to enter itself...

Vernor Vinge: A Fire Upon the Deep: "How could this happen?...

...A million schedules were suddenly advanced. An orderly flowering was out of the question now, and so there was no more need for the humans left in the Lab. The change was small for all its cosmic significance. For the humans remaining aground, a moment of horror, staring at their displays, realizing that all their fears were true (not realizing how much worse than true). Five seconds, ten seconds, more change than ten thousand years of a human civilization. A billion trillion constructions, mold curling out from every wall, rebuilding what had been merely superhuman. This was as powerful as a proper flowering, though not quite so finely tuned...

Comment of the Day: JEC argues, I think correctly, that L...

Comment of the Day: JEC argues, I think correctly, that Lawrence J. Christiano, Martin S. Eichenbaum, and Mathias Trabandt: On DSGE Models is significantly less serious and more bad than I had argued. I think he is correct:

JEC: Monday Smackdown: Oh Dear!: "To understand the state of academic macroeconomics, it's worth reading the first two sentences of the paper under discussion. They go like this...

...People who don���t like dynamic stochastic general equilibrium (DSGE) models are dilettantes. By this we mean they aren���t serious about policy analysis.

But who are these dilettantes? Keep reading:

In various sections we respond to some recent critiques of DSGE models. We focus on Stiglitz (2017) because his critique is a particularly egregious mischaracterization of the DSGE literature.

Just to be clear: Joe Stiglitz doesn't like DSGE models. Ergo, Joe Stiglitz���whose hobbies have included a stint as chief economist at the World Bank���is a dilettante, unserious about policy analysis. That doesn't sound quite right.

But what does dilettantism look like?

Macroeconomic policy questions involve trade-offs between competing forces in the economy. The problem is how to assess the strength of those forces for the particular policy question at hand.... Dilettantes who only point to the existence of competing forces at work���and informally judge their relative importance via implicit thought experiments���can never give serious policy advice.

After a set of examples, the authors continue:

In all of the above examples, the dilettante would be content to point out the existence of competing forces. But, policymakers at institutions like the International Monetary Fund are forced to assess their relative magnitude.

Whether this constitutes a remotely plausible characterization of the work of the World Bank's research department during Stiglitz's tenure is left as an exercise to NO IT'S NOT IT'S THE DUMBEST THING I'VE EVER HEARD.

Shhh...settle down you. I'm trying to be dry and pithy here.

But the best part is the very next sentence in which our authors give the entire game away:

DSGE models can and should play a central role in this assessment.

Hang on. "Can and should?" What has become of there is no other possible way and anyone who says otherwise is a big ol' stupidhead? Let us read on:

To be clear, when Madame Lagarde is briefed, she is not given the equations of a DSGE model or its impulse response functions. She is given a set of policy recommendations, and a rationale for each of them. She certainly understands that the recommendations are the result of a process in which layers of staff have worked with combinations of DSGE models, simple theoretical models and a-theoretical representations of the data.

Whoa...trippy. It turns out that, maybe, just maybe, there are other ways to quantitatively estimate the balance of forces and the probable range of net results of policy changes. Weird. It's almost like Lawrence Christiano, Martin Eichenbaum, and Mathias Trabandt knowingly chose to open their paper with a rhetorical salvo they knew to be pure defamatory bullsh-t.

For science!

I would change can and should play a central role to might, perhaps, play a peripheral role. There is no Calvo Fairy. Requiring that your policy analysis be based on one is asking for big trouble. Taking a calibrated representative-agent consumption Euler equation as the place you get your estimate of the slope of the investment-savings balance relationship between spending and interest rates is asking for big trouble. That is not where the connection between the investment-savings balance and the interest rate comes from. And taking the residual error from a production function and worshipping it, to any degree, as a fundamental driving variable is and always has been obvious pathetic idiocy.

A model that makes those three assumptions and then carefully tweaks itself to neutralize the destructive consequences of those three assumptions might be harmless���but why do all the work of so rendering it harmless rather than doing something useful? A model that makes those three assumptions and then does not carefully tweak itself to neutralize the destructive consequences of those three assumptions should never have been let into the building, and should be thrown out the window...

Peter Beinart Is a Mensch (Words I Did Not Think I Would Have Occasion to Say Department)

Must-Read: The lead makes me think: "Peter Beinart was a real idiot, and he is very very late to the party." For somebody to be such a moron as not to realize that people that Marty Peretz, Leon Wieseltier, Andrew Sullivan, and others were scorning as under qualified affirmative action hires had harder rows to hoe than he did���that almost beggars belief.

Nevertheless, in the words of Viktor Laszlo: "Welcome to the fight!":

Peter Beinart: Reflections of an Affirmative-Action Baby: "In 1991... Stephen Carter wrote... Reflections of an Affirmative Action Baby.... Little did I realize that the book���s title applied to me...

...Two years after Carter published his book, I joined the New Republic as a summer intern. I was thrilled. I had been reading the magazine since high school, and idolized its most prominent writers: Michael Kinsley, Hendrik Hertzberg, Andrew Sullivan, Michael Lewis, Michael Kelly, and, yes, Leon Wieseltier, who last month was accused of sexual misconduct by more than a dozen of his former colleagues. If someone had made TNR writers into baseball cards, by age 15 I would have had a complete set.... I���d spent years mimicking TNR.... I had the right sort of clips.... As a white man graduating from an Ivy League school, I also had the right sort of identity. It was difficult to disentangle the two. And I didn���t really try.... because the magazine afforded me extraordinary opportunity. Soon, I was not only working alongside people I revered, I was being given the chance to ascend to their level....

At some level, I knew the answer. White men from fancy schools advanced quickly at the New Republic because that���s who the owner and editor in chief, Marty Peretz, liked surrounding himself with. He ignored women almost entirely. There were barely any African Americans on staff.... TNR published an excerpt of Charles Murray and Richard Herrnstein���s book, The Bell Curve.... Marty felt a particular hostility to affirmative action. The irony���which I didn���t dwell on at the time���was that the magazine was itself a hothouse of racial and sexual preference... never stated formally.... To borrow Ta-Nehisi Coates���s metaphor, my race, gender, and class provided me a ���tailwind.��� I was running hard. But without that tailwind, it���s unlikely I would have become the magazine���s editor at age 28....

Carter['s]... affirmative action... remedied historic injustices. Mine perpetuated them.... Affirmative action enabled... Wieseltier���s sexual harassment... Leon���s sexual harassment reinforced... affirmative action. Men ran the magazine, and Leon���s behavior helped keep it that way. To ascend at TNR, you had to be a prot��g�� of either Marty or Leon���s... writing things they considered smart. For women, by contrast, mentorship was far trickier. Marty wasn���t an option. Leon was, but his mentorship often involved sexualization. If you accepted it, you gained a supporter but compromised yourself. If you spurned it, you became invisible to the magazine���s two most powerful men.

I���d like to say that when I became editor, I fundamentally changed all this. But I did not.... Had I challenged that culture more emphatically, I would probably not have become editor in the first place.... A series of moral compromises. From my time as a junior editor, I was handed pieces to edit���generally written or commissioned by Marty���that made sweeping, hostile generalizations about Palestinians, Arabs, or Muslims. I would cut as much as I felt I could get away with, and soften or nuance the rest. But I didn���t refuse to edit the pieces at all, since that would have imperiled my relationship with my mentors. (In fact, when I began writing more critically about Israeli policy after leaving the magazine, my relationships with both Marty and Leon swiftly declined.)...

When Marty fired Michael Kelly (who later became editor of The Atlantic), in part because Kelly was critical of Marty���s friend and former student, Al Gore, I considered resigning. But I feared I���d never find another job I enjoyed as much. Two years later, I was editor myself.... Those concessions created the template for my response to my former colleague Sarah Wildman when, in 2002, she told me about Leon���s inappropriate sexual advances. I believed her.... I also knew that I lacked authority over Leon.... So I called Marty���who spent most of his time in Cambridge, Massachusetts, and New York���and asked him to come to Washington to tell Leon that his behavior was unacceptable. (Marty has told Vox that I never reported the incident to him and that he doesn���t ���remember Sarah Wildman.��� Leon did not respond to my request for comment.)

Marty, Leon, and I met at the Willard Hotel. When I confronted him, Leon���who had a gift for intimidation���reacted ferociously. ���Is this some kind of intervention?��� he roared. Marty didn���t push back. That was it.... I could have threatened to resign.... I might have shifted the power dynamic, and forced Marty into taking some action that punished Leon and validated Sarah, which might have begun to erode the impunity that made Leon���s behavior possible. But I did not. By 2002, I had already made a series of moral compromises in order to stay at TNR, and in ways I didn���t fully realize, each laid the foundation for the next.

I don���t know know whether my experience is typical of men who are complicit in institutions that tolerate sexual harassment. What I do know is that the affirmative action I enjoyed, and the sexual harassment Sarah suffered, were connected. I was given extraordinary opportunity at TNR, in large measure, because talented women like Sarah Wildman were not. In this regard, I suspect, I have something in common with the supporters of Donald Trump. It���s not pleasant to realize that the bygone age you romanticize���the age when America was still great���was great for you, or people like you, because others were denied a fair shot....

A lot of white American men look at Barack Obama, and Hillary Clinton, and mass immigration, and the global competition for jobs, and the taking down of Confederate monuments, and even the revolt against sexual harassment, and fear all this means there will be less left for them. And they experience these attacks on their privilege as a desecration of the natural order, an attack on institutions that benefitted them, and to which they felt deep loyalty in return...

Comment of the Day: Sir Kraab: "A Sikh, an athetist, and ...

Comment of the Day: Sir Kraab: "A Sikh, an athetist, and a trans woman walk into a bar. They all have a drink together to celebrate their electoral victories."

Comment of the Day: Robert Halford: Louis CK and Matt Tai...

Comment of the Day: Robert Halford: Louis CK and Matt Taibbi: "I really should get out of this because I am actually enraged, both at the guy and at you...

...Louis CK did a bad job [of apology, but at least he admitted to what he'd done.

[Matt] Taibbi wrote a carefully-worded lawyer denial (I know one when I see one) which admitted to essentially nothing other than the obvious fact that he was a huge misogynist, which was admitted (despite being public!) only now because it is undeniable:

I continue to deny absolutely that I have ever sexually harassed anyone in any office, here or in Russia. No woman anywhere has ever accused me of anything of the sort, and I am confident that my former co-workers will report (many already have) that I have never exhibited anything like that kind of behavior, at work or elsewhere...

is carefully worded to say exactly the following���I do not believe any of my former coworkers will come forward with evidence of any crime.

It leaves open the obvious, which is that he 100% did shitty stuff outside of the office and presence of his coworkers. Plus he wrote a purported non-fiction account admitting to being an unbelievable shit. So he admits what is undeniable, the misogyny, but also somehow also downplays it, while carefully lawyering over what his actual conduct was, 100% certainly after discussing with an actual lawyer.

Stop defending the asshole. Look at yourself n the mirror and get a fucking grip. Think about whether this is where you want to draw a line or get invested in an argument.

Should-Read: Publius Aelius Aristides Theodorus (155): Fr...

Should-Read: Publius Aelius Aristides Theodorus (155): From The Roman Oration: "This city... covers mountain peaks... covers the land intervening, and... goes down to the sea...

...where the commerce of all mankind has its common exchange and all the produce of the earth has its common market. Wherever one may go in Rome, there is no vacancy to keep one from being, there also, in mid-city.... She rises great distances into the air, so that her height is not to be compared to a covering of snow but rather to the peaks themselves. And as a man who far surpasses others in size and strength likes to show his strength by carrying others on his back, so this city, which is built over so much land, is not satisfied with her extent. but raising upon her shoulders others of equal size, one over the other, she carries them.... If one chose to unfold, as it were, and lay flat on the ground the cities which now she carries high in air, and place them side by side, all that part of Italy which intervenes would, I think, be filled and become one continuous city stretching to the Strait of Otranto.... Of this city, great in every respect, no one could say that she has not created power in keeping with her magnitude. No, if one looks at the whole empire and reflects how small a fraction rules the whole world, he may be amazed at the city, but when he has beheld the city herself and the boundaries of the city, he can no longer be amazed that the entire civilized world is ruled by one so great....

The sea like a girdle lies extended, at once in the middle of the civilized of the civilized world and of your hegemony. Around it lie the great continents greatly sleeping, ever offering to you in full measure something of their own. Whatever the seasons make grow and whatever countries and rivers and lakes and arts of Hellenes and non-Hellenes produce are brought from every land and sea, so that if one would look at all these things, he must needs behold them either by visiting the entire civilized world or by coming to this city. For whatever is grown and made among each people cannot fail to be here at all times and in abundance. And here the merchant vessels come carrying these many products from all region in every season and even at every equinox, so that the city appears a kind of common emporium of the world.

Cargoes from India and, if you will, even from Arabia the Blest one can see in such numbers as to surmise that in those lands the trees will have been stripped bare and that the inhabitants of these lands, if they need anything, must come here and beg for a share of their own. Again one can see Babylonian garments and ornaments from the barbarian country beyond arriving in greater quantity and with more ease than if shippers from Naxos or from Cythnos, bearing something from those islands, had but to enter the port of Athens. Your farms are Egypt, Sicily and the civilized part of Africa.

Arrivals and departures by sea never cease, so that the wonder is not that the harbor has insufficient space for merchant vessels, but that even the see has enough, if it really does.

And just as Hesiod said about the ends of the Ocean, that there is a common channel where all waters have one source and destination, so there is a common channel to Rome and all meet here, trade, shipping, agriculture, metallurgy, all the arts and crafts that are or ever have been, all the things that are engendered or or grow from the earth. And whatever one does not see here neither did nor does exist. And so it is not easy to which is greater, the superiority of this city in respect to the cities that now are or the superiority of this city respect to the empires that ever were....

The present regime naturally suits and serves both rich and poor. No other way of life is left. There has developed in your constitution a single harmonious, all-embracing union; and what formerly seemed to be impossible has come to pass in your time: maintenance of control over an empire, over a vast one at that, and at the same time firmness of rule without unkindness....

When were there so many cities both inland and on the coast, or when have they been so beautifully equipped with everything? Did ever a man of those who lived then travel across country as we do, counting the cities by days and by days on the same day through two or three cities as if passing through sections of merely one?... It might very well be said that while the others have been kings, as it were, of open country and strongholds. you alone are rulers of civilized communities.

Now all the Greek cities rise up under your leadership, and the monuments which are dedicated in them and all their embellishments and comforts redound to your honor like beautiful suburbs. The coasts and interiors have been filled with cities, some newly founded, others increased under and by you.... Taking good care of the Hellenes as of your foster parents, you constantly hold your hand over them, and when they are prostrate, you raise them up. You release free and autonomous those of them who were the noblest and the leaders of yore, and you guide the others moderately with much consideration and forethought. The barbarians you educate, rather mildly or sternly according to the nature that each has, because it is right that those who are rulers of men be not inferior to those who are trainers of horses. and that they have tested their natures and guide them accordingly.

As on holiday the whole civilized world lays down the arms which were its ancient burden and has turned to adornment and all glad thoughts with power to realize them. All the other rivalries have left the cities, and this one contention holds them all, how each city may appear most beautiful and attractive. All localities are full of gymnasia, fountains, monumental approaches, temples, workshops, schools, and one can say that the civilized world, which had been sick from the beginning, as it were, has been brought by the right knowledge to a state of health. Gifts never cease from you to the cities, and it is not possible to determine who the major beneficiaries have been, because kindness is the same to all.

Cities gleam with radiance and charm, and the whole earth has been beautified like a garden. Smoke rising from plains and fire signals for friend and foe have disappeared, as if a breath had blown them away, beyond land and sea. Every charming spectacle and an infinite number of festal games have been introduced instead. Thus like an ever-burning sacred fire the celebration never ends, but moves around from time to time and people to people, always somewhere, a demonstration justified by the way all men have fared. Thus it is right to pity only those outside your hegemony, if indeed there are any, because they lose such blessings....

You have measured and recorded the land of the entire civilized world; you have spanned the rivers with all kinds of bridges and hewn highways through the mountains and filled the barren stretches with posting stations; you have accustomed all areas to a settled and orderly way of life.... Though the citizens of Athens began the civilized life of today, this life in its turn has been firmly established by you, who came later but who, men say, are better.

There is no need whatsoever now to write a book of travels and to enumerate the laws which each country uses. Rather you yourselves have become universal guides for all; you threw wide all the gates of the civilized world and gave those who so wished the opportunity to see for themselves; you assigned common laws for all and you put an end to the
which were amusing to describe but which, if one looked at them from the standpoint of reason, were intolerable; you made it possible to marry anywhere, and organized all the civilized world, as it were. into one family....

The gods, beholding, seem to lend a friendly hand to your empire in its achievement and to confirm to you its possession���Zeus, because you tend for him nobly his noble creation, the civilized world; Hera, who is honored because of marriage rites properly performed; Athena and Hephaestus because of the esteem in which the crafts are held; Dionysius and Demeter, because their crops are not outraged; Poseidon because the sea has been cleansed for him of naval battles and has received merchant vessels instead of triremes. The chorus of Apollo, Artemis and the Muses never ceases to behold its servants in the theaters; for Hermes there are both international games and embassies.

And when did Aphrodite ever have a better chance to plant the seed and enhance the beauty of the offspring, or when did the cities ever have a greater share in her blessings? It is now that the gracious favors of Asclepius and the Egyptian gods have been most generously bestowed upon mankind. Ares certainly has never been slighted by you. There is no fear that he will cause a general disturbance as when overlooked at the banquet of the Lapiths. On the contrary, he dances the ceaseless dance along the banks of the outermost rivers and keeps the weapons clean of blood. The all-seeing Helius, moreover, casting his light, saw no violence or injustice in your case and marked the absence of woes such as were frequent in former times. Accordingly, there is good reason why he looks and shines with most delight upon your empire...

Notes on Mark Koyama on Rome on Medium...

Mark Koyama: Could Rome Have Had an Industrial Revolution?/span>

The Malthusian Epoch and Its End

The agrarian age Malthusian epoch in human economic-demographic history had three principal driving characteristics:

Technological and organizational advance was slow and stable relative to movements in population.

Standards of living wer near "subsistence", in that increases in living standards produced increases in population growth, and decreases in living standards declines.

Resources were important, inasmuch as average productivity declined with increasing population, adjusting for the state of technology and organization.

In the Malthusian epoch living standards were near "subsistence": just enough above the level the would have produced zero population growth to generate slow population growth at the rate warranted by the slow advance of technology and organization. When population growth was faster than that warranted rate, living standards tended to decline and population growth thus to slow. When population growth was faster than that warranted rate, living standards would then rise and population growth would then accelerate.

In history, humanity broke out of the Malthusian epoch. The pace of technological and organizational advance became rapid enough that sustaining the then-warranted rate of population growth required living standards that were high enough above "subsistence" that other factors became dominant. People became rich enough and literate enough to take an extra degree of control of their own fertility. Malthus���s preventative and positive checks ceased to rule. Population growth fell below the rate that would have kept the world poor in barefoot. And modern economic growth began.

In history, we speak of the commercial, industrial, and second industrial revolutions over 1500-1930 that carried first northwest Europe and now the rest of the world from Malthusian poverty to today���s epoch of modern economic growth. But was the door through which we exited agrarian age Malthusian poverty the only possible door? Was the economic-demographic-political-cultural history as it really happened in northwest Europe the only key?

The most obvious way, to me at least, to start thinking about this question is the Diamond-Kremer-Romer assertion: Two heads are better than one. It is not just in software that ���with enough eyes, all bugs are shallow���. Thanks to language, humans are an anthology intelligence: what useful thoughts one of us has, all can quickly copy and learn. Thanks to writing, the human anthology intelligence binds time: our shared collective brain is composed not just of the living but of many of the the dead as well; in large part what they knew we know too; and so we do not have to painfully relearn it via our own experience.

More brains: faster technological and organizational progress. How much faster? There are a great number of possibilities.

Quantifying "Two Heads Are Better than One"

Let us take four cases as possible rough descriptions of the agrarian age from 5000 BCE to 1500 CE:

Two heads are better than one, and twice as good as one: the rate of technological and organizational progress might be proportional to the global population.

While two heads are better than one, each of us has only a limited amount of time to listen; The rate of technological and organizational progress might be proportional to the square root of the global population.

While two heads are better than one, we really are far from being a true anthology intelligence: each doubling of the population only does as much to advance inmeaning that the rate of technological and organizational progress might be proportional to the logarithm of the global population.

Two heads are not better than one after all: technological and organizational progress does not fall from the air, but rather drops from the air at a near-constant rate.

We know that there were about 5 million people on the earth in 5000 BCE, when the agrarian age more or less began. We know that there were about 50 million people on earth in 1000 BCE. What do those two benchmarks imply about when there would be enough people on the earth thinking and communicating enough about better ways to perform tasks and organize societies to break us out of Malthusian poverty?

We could write down our four possible rought description cases in math, using "c" rather than "t" for our time index because there is no real point to working in units of less than a century, and to remind us that that is what we are doing:

$ \frac{dP_{c}}{dc} = ��{P_{c}}^{2} $

$ \frac{dP_{c}}{dc} = ��{P_{c}}^{(3/2)} $

$ \frac{dP_{c}}{dc} = P_{c}\left(��{\ln{P_{c}}}\right) $

$ \frac{dP_{c}}{dc} = ��P_{c} $

And then use http://wolframalpha.com to get us analytic solutions:

$ \frac{dP_{c}}{dc} = ��{P_{c}}^{2} ��� P_{c} = \frac{1}{A - ��c} $

$ \frac{dP_{c}}{dc} = ��{P_{c}}^{(3/2)} ��� P_{c} = \frac{4}{{(A ��c)}^2}$

$ \frac{dP_{c}}{dc} = P_{c}\left(��{\ln{P_{c}}}\right) ��� P_{c} = li^{^{(-1)}}\left(A ��c\right)$

$ \frac{dP_{c}}{dc} = ��P_{c} ��� P_{c} = Ae^{(��c)}$

(Yes, I had forgotten that the "log integral" function $ li( ) $ existed, let alone that its inverse $ li^{^{(-1)}}() $ was a thing.)

But unless you know or remember and have much more intuition than I do for this math, it is simpler to BF&MI���Brute Force & Massive Ignorance���It:

# take a century to be our time period
# take our starting point to be 5000 BCE :

year = range(-5000, 2000, 100)

# initialize our four cases with an initial global
# population in 5000 BCE of 5 million:

pop_con = [5]
pop_log = [5]
pop_sqr = [5]
pop_lin = [5]

# by trial-and-error determine the �� values that
# get us to 50 million population by 1000 BCE:

gamma_con = 0.0593
gamma_log = 0.0231
gamma_sqr = 0.0159
gamma_lin = 0.00475

# calculate human populations up through 2000
# assuming a "Malthusian" regime

for i in range(0,70):
pop_con = pop_con [pop_con[i] * (1 gamma_con)]
pop_log = pop_log [pop_log[i] * (1 gamma_log * np.log(pop_log[i]))]
pop_sqr = pop_sqr [pop_sqr[i] * (1 gamma_sqr * (pop_sqr[i]**(0.5)))]
pop_lin = pop_lin [pop_lin[i] * (1 gamma_lin * pop_lin[i])]

# shove the results into a pandas dataframe:

pop_df = pd.concat([pd.Series(dict(zip(year, pop_con)), index = year),
pd.Series(dict(zip(year, pop_log)), index = year),
pd.Series(dict(zip(year, pop_sqr)), index = year),
pd.Series(dict(zip(year, pop_lin)), index = year)],
axis=1)
pop_df.columns = ['pop_con', 'pop_log', 'pop_sqr', 'pop_lin']

# and plot:

pop_df[0:46].plot()

The "two heads are twice as good as one" case clearly exits the Malthusian regime before the year 1. Let's take a look at what happens:

pop_df[40:51]

By 700 BCE the "two heads are better than one" case is already seeing global human population growing at more than 50 percent per century. By 300 BCE the population of the globe is 3 billion. The economy is clearly no longer well-described by the Malthusian framework, and so that model equation blows up. The conclusion is that if two heads really were twice as good as one as far as technological and organizational progress are concerned, then a world with 5 million people in 5000 BCE and 50 million in 1000 BCE would have escaped from agrarian age Malthusian poverty into something else technologically and organizationally advanced well before the year one.

So let's drop that case and look at the other 3:

pop_df = pop_df.drop(['pop_lin'], axis=1)

# and plot:

pop_df[0:56].plot()

The "Two Heads Are Root-2 Better than One" case tuned to hit 5 million population in 5000 BCE and 50 million in 1000 BCE overshot actual global population in the year 1. (There is, remember, no year zero, no matter what the graph and arithmetic may say.) We think there were 170 million people then. The Root-2 case had 198. The "Two Heads Are Log-2 Better than One" case similarly tuned undershot global population in the year 1: it had only 129 million people. And the constant growth case way undershot���90 million people, only half of the actual population then. The first millennium BCE was a good thousand years for humanity: it really does look like there was then something to "Two Heads Are Better than One".

Take a look at the numbers:

pop_df[45:61]

Both the "Root-2" and the "Log" cases would have predicted a further growth acceleration in the first millennium CE. By 600 CE the actual human population was, we think, some 200 billion. The "Root-2" case expected nearly a billion, the commercial revolution well-launched, and the Malthusian population equation ceasing to be adequate. The "Log" case, having undershot in the year 1, overshot by year 600. It expected a doubling of human population in the 600 years between Jesus and Muhammed, rather than the much smaller increase from about 170 to 200 million that we actually saw.

The "Two Heads Are Better than One" approach thus focuses our attention on what was, for it, a profound anomaly. The world in 600 CE���whether in China, the Roman Empire or ex-Empire, or in between���fell far short of what its Whig progressive narrative would have expected to have been created by then.

Decline and Fall

There was indeed a great anomaly here. We find, in Mark Koyama's excellent medium post: https://medium.com/@MarkKoyama/could-rome-have-had-an-industrial-revolution-4126717370a2. Drawing on Kyle Harper and William Jongman, he quotes first Kyle on Rome in the second century CE, the age of the Antonine dynasty:

Peace, law, and transportation infrastructure fostered the capillary penetration of markets everywhere. The clearing of piracy from the Mediterranean in the late Republic may have been the single most critical precondition for the burst of commercial expansion that the Romans witnessed; risk of harm has often been the costliest impediment to seaborne exchange. The umbrella of Roman law further reduced transaction costs. The dependable enforcement of property rights and a shared currency regime encouraged entrepreneurs and merchants.... Roman banks and networks of commercial credit offered levels of financial intermediation not attained again until the most progressive corners of the seventeenth-eighteenth century global economy. Credit is the lubricant of commerce, and in the Roman empire the gears of trade whirred... (Harper, 2017, p 37)

And then William:

Crucial performance indicators show dramatic aggregate and per capita increases in production and consumption from the 3rd century BCE, or sometimes a bit later, until the Roman economy reached a spectacular peak during the 1st century BCE and the 1st century CE, lasting until perhaps the middle of the 2nd century CE... (Jongman, 2015, 81)

But this was something that we knew, and that the Renaissance and post-Renaissance saw clearly. We have all read our Gibbon, have we not?:

If a man were called to fix the period in the history of the world, during which the condition of the human race was most happy and prosperous, he would, without hesitation, name that which elapsed from the death of Domitian to the accession of Commodus. The vast extent of the Roman empire was governed by absolute power, under the guidance of virtue and wisdom. The armies were restrained by the firm but gentle hand of four successive emperors, whose characters and authority commanded involuntary respect. The forms of the civil administration were carefully preserved by Nerva, Trajan, Hadrian, and the Antonines, who delighted in the image of liberty, and were pleased with considering themselves as the accountable ministers of the laws. Such princes deserved the honor of restoring the republic, had the Romans of their days been capable of enjoying a rational freedom. The labors of these monarchs were overpaid by the immense reward that inseparably waited on their success; by the honest pride of virtue, and by the exquisite delight of beholding the general happiness of which they were the authors...

And Aldo Schiavone's The End of the Past http://amzn.to/2yzerRO makes great use of the Roman Oration of Publius Aelius Aristides Theodorus in 155 CE https://www.jstor.org/stable/1005702:

Whatever the seasons make grow and whatever countries and rivers and lakes and arts of Hellenes and non-Hellenes produce are brought from every land and sea, so that if one would look at all these things, he must needs behold them either by visiting the entire civilized world or by coming to this city. For whatever is grown and made among each people cannot fail to be here at all times and in abundance. And here the merchant vessels come carrying these many products from all region in every season and even at every equinox, so that the city appears a kind of common emporium of the world. Cargoes from India and, if you will, even from Arabia the Blest one can see in such numbers as to surmise that in those lands the trees will have been stripped bare and that the inhabitants of these lands, if they need anything, must come here and beg for a share of their own. Again one can see Babylonian garments and ornaments from the barbarian country beyond arriving in greater quantity and with more ease than if shippers from Naxos or from Cythnos, bearing something from those islands, had but to enter the port of Athens. Your farms are Egypt, Sicily and the civilized part of Africa.... And whatever one does not see here neither did nor does exist....

When were there so many cities both inland and on the coast, or when have they been so beautifully equipped with everything? Did ever a man of those who lived then travel across country as we do, counting the cities by days and by days on the same day through two or three cities as if passing through sections of merely one?... It might very well be said that while the others have been kings, as it were, of open country and strongholds. you alone are rulers of civilized communities.... As on holiday the whole civilized world lays down the arms which were its ancient burden and has turned to adornment and all glad thoughts with power to realize them.... All localities are full of gymnasia, fountains, monumental approaches, temples, workshops, schools, and one can say that the civilized world, which had been sick from the beginning, as it were, has been brought by the right knowledge to a state of health. Gifts never cease from you to the cities, and it is not possible to determine who the major beneficiaries have been, because kindness is the same to all.... You have measured and recorded the land of the entire civilized world; you have spanned the rivers with all kinds of bridges and hewn highways through the mountains and filled the barren stretches with posting stations; you have accustomed all areas to a settled and orderly way of life.... Though the citizens of Athens began the civilized life of today, this life in its turn has been firmly established by you, who came later but who, men say, are better....

The gods, beholding, seem to lend a friendly hand to your empire in its achievement and to confirm to you its possession���Zeus, because you tend for him nobly his noble creation, the civilized world; Hera, who is honored because of marriage rites properly performed; Athena and Hephaestus because of the esteem in which the crafts are held; Dionysius and Demeter, because their crops are not outraged; Poseidon because the sea has been cleansed for him of naval battles and has received merchant vessels instead of triremes. The chorus of Apollo, Artemis and the Muses never ceases to behold its servants in the theaters; for Hermes there are both international games and embassies. And when did Aphrodite ever have a better chance to plant the seed and enhance the beauty of the offspring, or when did the cities ever have a greater share in her blessings? It is now that the gracious favors of Asclepius and the Egyptian gods have been most generously bestowed upon mankind...

Schiavone further quotes from F.W. Walbank in 1946:

What we must ask is: Why within a hundred years did this vigorous and complicated structure [the principate of the Antoninesl cease to operate as a going concern? Why has there been not a straight upward line from the time of Hadrian to the twentieth century, but instead the familiar sequence of decay, middle ages, renaissance, and modern world?...

and seeks:

an important priority. An explanation for why Roman society failed to rise any further once it had reached the peak of its development, why there was no transformative impulse of the kind that Pirenne identified in Europe after the year 1000," must be a prerequisite for
ensuing collapse of Rome and its particular characteristics.... [What were] the structures and events that prevented the formation of stronger evolutionary ties and rendered the end of the ancient world an epochal period in... history?... It would be superficial and simplistic to interpret the entire history of Byzantium in the sixth to fifteenth centuries as simply the extreme protraction of a long period of stagnation, but it is undeniable that the continuity
East brought stability to features and characteristics that were entirely different from those that the crisis imposed on the west. Thus, when Rostovtzeff and Walbank raised their question ("Why has there been not a straight upward line of progress from the time o fHadrian to the twentieth century?" in Walbank's words; and "Why had modern civilization to be built up laboriously as something new... instead of being a direct continuation of it?" as Rostovtzeff put it), neither was inventing an improbable historical situation.... They were performing a kind of conceptual experiment that brought them right to the heart of the history of Rome and the history of Europe.... The emphasis is on something that can be present only in modern consciousness: its failure to develop, the potential transformations that went unrealized, just when the first signs of this evolution appeared most clear...

And So We Finally Get to Mark Koyama...

Mark:

First, there those who tend to think that market expansion is sufficient for sustained economic growth.... Second, there are those who argue that colonial empires or natural resources like coal were crucial for modern economic growth.... Third, there are those who argue that ultimately only innovation can explain the transition to modern economic growth... divided between those who seek to explain the increase in innovation in purely economic terms... and those who... that the answer has to be sought... in something... broadly defined as culture....

Adherents of... the view that trade, commerce, and market development were a sufficient condition for modern economic growth should find the Roman Industrial Revolution counterfactual highly appealing.... Similarly... the Roman empire was a coherent, capitalist, ���world system���... colonies... periphery... based around the Mediterranean economy rather than the Atlantic world, but there seems little intrinsic reason why it should have been less successful than the early modern world system in generating economic growth....

The demand for slaves soared after 200 BCE, and... their ready supply encouraged landlords to practice commercial agriculture on a vast scale. Such an economy was ill-suited for modern economic growth....

The arguments of McCloskey and Mokyr suggest greater skepticism towards the counterfactual we have outlined. Mokyr argues that made 18th century Britain distinctive was a ���culture of growth���... the importance of a competitive Republic of Science.... Similarly, I am not aware of evidence of the kind of rhetorical change in attitudes towards commerce in the Rome world that McCloskey documents in the 17th century Dutch Republic or 18th century England���no new-found respect for traders and merchants, over and above soldiers and adventurers, and no evidence of lessening distain for commerce or business. If these cultural attitudes were the binding constraint in late medieval and early modern Europe, then they were equally binding in antiquity. I���ve speculated... on the ways in which slavery and other Roman institutions reinforced a cultural ethos that was hostile to trade-based economic betterment.... But I would be eager to read counter evidence....

All of this suggests that a better understanding of why sustained or modern economic growth did not occur during earlier ���efflorescences��� can help us better understand which factors were important in the explaining the transition that did take place after 1800.

References


Publius Aelius Aristides Theodorus (155): The Roman Oration
Helen Dale: Kingdom of the Wicked Book One: Rules
Edward Gibbon (1782): History Of The Decline And Fall Of The Roman Empire
Kyle Harper: The Fate of Rome: Climate, Disease, and the End of an Empire
Mark Koyama: Could Rome Have Had an Industrial Revolution?
Mark Koyama: The End of the Past
Michael Rostovtzeff: THE SOCIAL AND ECONOMIC HISTORY OF THE ROMAN EMPIRE
Aldo Schiavone: The End of the Past: Ancient Rome and the Modern West
F.W. Walbank (1946): The decline of the Roman Empire in the West
Wolfram Alpha: Computational Knowledge Engine




Housekeeping


Note to Self: View jupyter notebook from dropbox (or other) links:

Dropbox: change: "https://www.dropbox.com/" to: "http://nbviewer.jupyter.org/urls/dl.d... then load the url...
Else: change: "https://" to "http://nbviewer.jupyter.org/"; then load the url...

https://www.dropbox.com/s/xls7tvpgdq5ipcc/workingâKoyama Notes.ipynb?dl=0




MOAR Housekeeping

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IPython.OutputArea.prototype._should_scroll = function(lines) {
return false;}

# keep output cells from shifting to autoscroll...

# set up the environment by reading in libraries:
# os... graphics... data manipulation... time... math...
# statistics...

import sys
import os
from urllib.request import urlretrieve

import matplotlib as mpl
import matplotlib.pyplot as plt
%matplotlib inline
import PIL as pil
import plotly
plotly.tools.set_credentials_file(username='delong',
api_key='d6vMMwVn4sEBmR2MLN9H')
import plotly.plotly as py
import plotly.graph_objs as go
from plotly.graph_objs import Scatter
from IPython.display import Image

import pandas as pd
from pandas import DataFrame, Series
import pandas_datareader
from datetime import datetime

import scipy as sp
import numpy as np
import math
import random

import statsmodels
import statsmodels.api as sm
import statsmodels.formula.api as smf

# graphics setup: seaborn-whitegrid and figure size...

plt.style.use('seaborn-whitegrid')

figure_size = plt.rcParams["figure.figsize"]
figure_size[0] = 10
figure_size[1] = 7
plt.rcParams["figure.figsize"] = figure_size