The following article comes via the New Scientist magazine. I thought it was very interesting. I also wonder if there is further uses for this research.....
Calculated violence: Numbers that predict revolutions
The mathematics underpinning the rise and fall of empires suggest that the US faces imminent and bloody unrest. How worried should we be?
PETER TURCHIN thinks he can see the
future. Unlike the fortune teller you might find at a seaside carnival,
he needs no crystal ball. Instead, the tools of his trade are
mathematics and testable theories. Armed with these, his goal is nothing
less than to revolutionise the study of history, turning it from a mass
of anecdotes into a rigorous, predictive science.
Turchin calls his new discipline cliodynamics,
after Clio, the classical Greek muse of history, and so far its biggest
focus has been the fate of empires. Now Turchin is using patterns he
has found underlying their rise and fall to make predictions of
political changes to come. His forecast is alarming. If his calculations
are correct, the US faces major civil unrest and political violence
sometime around the end of this decade.
Critics call Turchin's approach
simplistic and naive, with some arguing that recorded history is too
short to provide adequate evidence for his assertions. Turchin,
meanwhile, is happy to have his theories tested - and hopes that he is
wrong. If things are left to run their course, we should know quite
soon. There is another option, however. We could head off any
instability, Turchin says - but only if we take some unpalatable
remedies now.
Turchin has not always been a bull in
the china shop of history. A professor at the University of Connecticut,
he is a respected mathematical ecologist with a lengthy list of
influential papers on animal movements and populations behind him. "It
was a midlife crisis," he recalls. "I turned 40, and I had achieved
tenure and some notoriety in population dynamics. At some point I
thought, 'Where is the challenge?'" So he started looking for a new
field where he could put his formidable mathematical chops to work. "It
turns out that the only science that didn't have that already was
history. The field was wide open." So Turchin rolled up his sleeves and
began the familiar process of forming hypotheses and testing them.
That was 15 years ago. Since then he
has used his analytical approach to address all sorts of historical
questions, including how religions spread, why empires tend to arise
where steppe meets farmland, and why empires collapse. "The goal is to
make history an explanatory science, which means rejecting some theories
in favour of others," he says. There are more than 200 explanations for
the fall of the Roman Empire, for example, because historians keep
coming up with new ideas but never cull the old ones, he says.
Cliodynamics, by contrast, aims to work out which theories best fit the
evidence.
Perhaps it is no surprise that his
adopted discipline has not greeted him with open arms. Most historians
have been trained to dig as deeply as they can into the details of a
culture to understand what makes that particular time and place unique.
"Historians tend to tell stories," says Anthony Beavers, a philosopher
and cognitive scientist at the University of Evansville, Indiana. "They
get a cast of characters and follow them through events." This focus on
the particular understandably leaves many historians deeply suspicious
of any analysis that treats individual cultures as mere data points.
A few disciplines traditionally buck
this trend for subjectivity, such as economic history, which is
intrinsically quantifiable. And the explosion in computing power means
that, increasingly, data analysis is being used to address diverse
historical questions. Fred Gibbs and Dan Cohen at George Mason
University in Fairfax, Virginia, for example, plundered the online
library Google Books to test the long-held belief that religious faith
declined in England during Victorian times. Tracking the use of
religiously charged words in the title of every book published in the UK
during the 19th century, they charted a sharp fall in the use of "God"
and "Christ" after about 1850, while the more neutral "Jesus", which can
refer to the historical person without the religious baggage, held
relatively constant (Victorian Studies, DOI: 10.1353/vic.2011.0146). But Turchin's approach goes beyond the analysis of trends such as these to try to pick out repeating patterns in history.
Reasoning that the fate of an empire
rests ultimately on social cohesion, he has used historical records to
track the prevalence of what he calls collective violence - deaths due
to political assassinations, riots and civil wars, but not international
wars or ordinary crimes - in three major civilisations, the Roman
Republic, medieval Europe and Tsarist Russia. Applying mathematical
tools borrowed from population biology, he has found that in each case
deaths from collective violence follow two superimposed cycles, one
spanning two to three centuries and the other about 50 years (Secular Cycles,
Princeton University Press, 2009). What's more, he thinks his data
provide enough leverage to understand what drives the longer cycle.
The likeliest explanation, he says, is
an idea known as demographic-structural theory, proposed two decades
ago by Jack Goldstone at George Mason University in Arlington, Virginia.
This argues that in a prosperous culture, population growth or
advancing technology eventually leads to an oversupply of labour. That
is good news for an expanding upper class who can more easily exploit an
increasingly desperate labour force. Eventually, though, the society
becomes so top-heavy that even some members of the elite can no longer
afford the good life. Factionalism sets in as the upper classes fight
among themselves, social cohesion declines, and the state begins to lose
control of its citizens. Then, and only then, does widespread violence
break out. Anarchy reigns until enough people fall out of the elite
classes, at which point growth and prosperity can return.
A tidy story, but is it true?
Fortunately for Turchin, the theory makes predictions that can be
tested. In particular, it predicts that social collapse and widespread
violence do not rear their heads when life first gets grim for the
working classes, as you would expect if workers' misery were the
catalyst. Instead, unrest should follow a generation or two later,
because it takes that long to accumulate an excess of wealthy, highly
educated elites. This is exactly what Turchin found when he compared the
timing of collective violence with economic indicators such as wages,
social inequality and population growth - a measure of labour supply -
in the three civilisations. As a further test, he looked at the dates on
coins in hoards unearthed by archaeologists. Coin hoards are an
excellent proxy for political unrest, since their owners must have
buried them in fear during dangerous times and then experienced some
misfortune that prevented them from digging them up later. Again, he
found that civil war lagged behind economic hardship by a generation or
two. Moreover, the same pattern holds true for the US over the past 200
years, he reports in a new paper (Journal of Peace Research, vol 4, p 577 and see diagram).
Turchin is less certain about the
causes of the 50-year cycle. His best guess is that people who grow up
in times of strife come to crave stability, while those who grow up in
stable times are more willing to rock the boat. This leads, he thinks,
to a two-generation cycle of stability and violence. "It's not as well
tested," he says. "Take it with a grain of salt."
Oversimplifying reality
That will not be enough to make
Turchin's ideas palatable to his critics. Detractors point out that his
data can be a bit shaky even for the longer cycles. "One of the things
to keep in mind is how little data we actually have. We've only been
keeping records for 5000 years," says Beavers. As a result, Turchin's
analysis tracks just eight complete long cycles in each of the
civilisations he looked at. What's more, there are times when his
interpretations of the evidence falls short, says historian Johannes
Preiser-Kapeller at the Austrian Academy of Sciences in Vienna. For
example, Turchin points to a decline in population in Tang-dynasty China
during the 9th century as evidence of his theory, but this decline is
more apparent than real, says Preiser-Kapeller. What really happened was
that the state's power decreased so that the census failed to include
people in outlying provinces.
Turchin's cyclic theory of history
also seems to leave out any role for unique events such as changes in
climate, disease outbreaks or the appearance of a remarkable,
history-changing individual. "The patterns are more complex, more
chaotic, than the patterns created by his model," says Preiser-Kapeller.
Turchin readily admits that his
broad-brush approach oversimplifies reality, but that doesn't worry him.
"Any model, any theory, has to oversimplify things. That's how you find
the critical variables," he says. "The question is how good is the
theory at explaining and being tested by data. That's how we know
whether we're focusing on the correct variables." He does concede that,
occasionally, history can turn on the actions of a single person. For
example, military historians have calculated that Napoleon's presence at
a battle improved the odds of victory by the same amount as having 30
per cent more troops. On the other hand, he notes, many apparently
unique contributions may be less dependent on individuals than they
appear. If, for example, a Tunisian fruit vendor had not triggered the
Arab Spring by immolating himself, some other factor would likely have
precipitated the crisis.
In the end, history will prove Turchin
right or wrong - and we won't have to wait long to find out. From the
start, he has argued that the cycles underlying the rise and fall of
empires closely resemble the population cycles that he used to study in
rodents and insects. If so, it should be possible to predict what those
cycles might do, just as any decent biologist can predict whether
lemmings or snowshoe hares will be scarce or abundant next year.
Two years ago, Turchin put his
reputation on the line by predicting publicly that political instability
in the US and western Europe will shoot up in the coming decade (Nature, vol 463, p 608).
In his new paper he provides more evidence for an impending crisis in
the US, where both cycles look to be approaching a peak in 2020.
Allowing for some imprecision in his calculations, Turchin says that if
we make it to 2030 without major turmoil he will conclude that his
prediction - and hence the underlying theory - is wrong. He doesn't
think that will happen, though, and estimates that he has an 80 per cent
chance of being right.
The scale of the potential unrest,
although more uncertain, also concerns him. "It is easier to predict
timing than the height of the peak. My feeling is that it's going to be
worse than we expect. Hopefully I'm wrong - I have to live through
this."
If Turchin is right about the things
that drive the cycles, there may be ways to avert the crisis. For
example, increasing tax rates on high earners should help reduce social
inequality and slow the growth of elites. Turchin also suggests that the
US should reduce rates of immigration - a step he finds unpalatable
because he is himself an immigrant. "I'm not a xenophobe," he says.
"It's because the theory suggests that immigrants are depressing wages
and making the problem of inequality worse."
Turchin's third prescription may be
even more controversial: he says that fewer people should get a
university education, since degrees are traditionally a stepping stone
into the elite classes. He notes that collective violence in Europe in
the early 17th century and in pre-revolutionary Russia was closely
correlated with an oversupply of graduates.
Not many historians would be willing
to make such bold predictions. And Turchin has the scientist's openness
to being proven wrong. "The most convincing way to show that I'm wrong
is to propose an alternative theory that fits the data better," he says.
"That's what science is all about."
Taking the long view of history
Many scientists are happy to remain in their ivory towers. Not Peter Turchin. He believes his scientific analysis of history holds lessons for policymakers (see main story). If they want to avert civil upheaval, he argues, they need to understand the evolution of human cooperation and conflict.That is why he has recently become involved with the Evolution Institute, the world's first think tank applying evolutionary principles to policy issues. Set up in 2008 by David Sloan Wilson of Binghamton University, New York, the institute is already tackling an ambitious range of areas. Projects so far include redesigning neighbourhoods and building community parks to maximise good social interactions (New Scientist, 29 August 2011, p 28); changing school environments to make better use of children's innate ability to learn; incorporating an evolutionary perspective on human nature and behaviour into studies of economic decision-making; and studying how cultural evolution has shaped the success and failure of nation states, focusing particularly on the different traditions within the Afghanistan-Pakistan region of Asia.
"Evolution is all about the relationship between an organism and its natural environment," says Sloan Wilson. That is why it can help us rethink the way we live.
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