Richard Melson

June 2005

Cliodynamics

http://www.eeb.uconn.edu/faculty/turchin/Clio.htm

A web page by Peter Turchin

The Wheel of Fortune

– an allegorical image of the cyclical nature of rise and fall of rulers, nations, empires, and civilizations.

One problem with it, however, is that it suggests a too mechanical view of historical dynamics. Regular cycles is just one of possible behaviors that can arise in nonlinear dynamical systems, and not the most common one.

Nonlinear feedbacks between different interacting components often cause dynamical systems to behave in complex ways (mathematical chaos is one such behavior).

Furthermore, in addition to endogenous feedbacks (interactions between its internal parts) dynamical systems may be affected by exogenous influences, which we often model as stochastic factors.

Stochastic exogenous factors combine with endogenous feedbacks to produce a great variety of complex dynamical behaviors in real-life dynamical systems, whether physical, biological, or social.

What is cliodynamics?

Many historical processes are dynamic.

Empires rise and fall, populations and economies boom and bust, world religions spread or wither.

Cliodynamics (from Clio, the muse of history, and dynamics, the study of temporally varying processes) is a branch of historical sociology that investigates such dynamical processes in history.

Because nonlinear dynamical systems are capable of very complex behaviors (see the side bar), explicit mathematical models are a necessary ingredient in any research program for investigating them.

We also need data describing how various aspects of the studied systems change with time.

Fortunately, much quantitative empirical material on historical systems has been made available over the last couple of decades by workers in the field of cliometrics, and we can confidently expect that this process will continue in the future.

The proposed general approach to investigating dynamical systems in history, therefore, is as follows. We start with verbal theories explaining historical change, either proposed by previous theorists, or formulated de novo. The verbal theories are translated into mathematical models, whose predictions can then be rigorously tested with cliometric data.

Historical Dynamics: Why States Rise and Fall

(2003, Princeton University Press)

More details on the historical dynamics research program are given in my 2003 book published by the Princeton University Press. The book describes a systematic application of the general approach, sketched above, to the question of what mechanisms explain territorial expansion and contraction of states.

Click here for the prospectus and sample chapters.

Although the book came out quite recently – in November 2003 – it reflects my thinking and results as of late 2002. Meanwhile the work continues. Below I list the recent developments (new analyses, manuscripts, etc) that took place since the book text was finalized. In the future I plan to continue adding stuff as it becomes available.

Recent Developments:

May 2005

WAR & PEACE & WAR: The Life Cycles of Imperial Nations by P. Turchin

I have completed a book draft that presents my ideas about historical dynamics in popular form. The book will be published by Pi Press, an imprint of Pearson Education, in September 2005. I am currently looking for reviewers; if you are willing to provide me with comments on the draft before June 15, please send me an e-mail.

March 2005

Review of Historical Dynamics in The Citizen Scientist by Kevin T. Kilty: here

December 2004

Review of Historical Dynamics in Economics of Transition by Paul Seabright: here

A news article about Historical Dynamics in Advance here

November 2004

East-West Orientation of Historical Empires by P. Turchin, J. M. Adams, and T. D. Hall

Does environment affect the ability of states to project power? If state expansion is more easily accomplished by staying within the same ecological zone, then state territories should be oriented in the east-west direction, mirroring the orientation of major ecological zones of the world. Our analysis of 62 largest empires in history supports this conjecture.

PDF of the article here

October 2004

Emergence of Cooperative Strategies from Elementary Actions in Agents with Neural Nets by Mikhail Burtsev and Peter Turchin

One of the greatest challenges in the modern biological and social sciences has been to understand the evolution of altruistic and cooperative behaviors. The main conceptual tool used in probing the logical coherence of proposed explanations has been game theory, including both analytical models and agent-based simulations. The game-theoretic approach yields clearcut results, but the simple structure of payoffs and a small fixed set of strategies, imposed by investigators, in some cases may be an unrealistic assumption. We describe a much more stringent test of the theory by developing a computer model in which agents are endowed with a limited set of receptors, a set of elementary actions, and a neural net in between. Behavioral strategies are not predetermined, but allowed to emerge in the process of evolution.

PDF of the article here

May 2004

Dynamical maps of evolution of the state system and metaethnic frontiers in Europe during the two millenia CE

These slides complement the material in Chapter 5 of my book on Historical Dynamics, where I empirically test the predictions of the metaethnic frontier theory. The basic matrix is the snapshots of political landscape of Europe and Mediterranean taken at 100 year intervals from 0 to 1800 BCE. On top of the matrix I overlayed metaethnic frontiers.

For European material see Appendix B of Historical Dynamics.

Locations of Near Eastern frontiers are still in process of being worked out, and will probably be revised in future.

These PowerPoint slides were presented at the Santa Fe Institute working group on Analyzing Complex Macrosystems. PowerPoint presentation here (22 MB)

April 2004

Dynamical feedbacks between population growth and sociopolitical instability in agrarian states

Most preindustrial states experienced recurrent waves of political collapse and internal warfare. One possible explanation of this pattern, the demographic-structural theory, suggests that population growth leads to state instability and breakdown, which in turn causes population decline.

Mathematical models incorporating this mechanism predict sustained oscillations in demographic and political dynamics.

Here I test these theoretical predictions with time-series data on population dynamics and sociopolitical instability in early modern England, the Han and Tang China, and the Roman Empire. Results suggest that population and instability are dynamically interrelated as predicted by the theory.

A PDF of the article is here

This manuscript (rejected by Science last Fall) was the basis of my presentation

at the Santa Fe Institute working group on Analyzing Complex Macrosystems.

Note added March 2005:

the manuscript is now in press in Structure and Dynamics

February 2004

Review of Historical Dynamics in Nature by Joseph Tainter: here

See my response to Tainter's review here

December 2003

Population Dynamics and Internal Warfare: a Reconsideration
by Peter Turchin and Andrey Korotayev

The hypothesis that population pressure causes increased warfare has been recently criticized on the empirical grounds. Both studies focusing on specific historical societies and analyses of cross-cultural data fail to find positive correlation between population density and incidence of warfare. In this paper we argue that such negative results do not falsify the population-warfare hypothesis. Population and warfare are dynamical variables, and if their interaction causes sustained oscillations, then we do not in general expect to find strong correlation between the two variables measured at the same time (that is, unlagged). We explore mathematically what the dynamical patterns of interaction between population and warfare (focusing on internal warfare) might be in both stateless and state societies. Next, we test the model predictions in several empirical case studies: early modern England, Han and Tang China, and the Roman Empire. . .

A manuscript submitted to Current Anthropology.
A PDF of the article is here
Supplementary Material (some details on data, analytical procedures) here

December 2003

Scientific Prediction in Historical Sociology: Ibn Khaldun meets Al Saud

One of the hallmarks of a mature discipline is its ability to make predictions that can be used to test scientific theories. Scientific predictions do not necessarily have to be concerned with future events; they can be made about what occurred in the past.

I illustrate such retrospective prediction with a case study of conversion to Christianity in the Roman Empire. The bulk of the paper deals with the logic and methodology of setting up a scientific prediction in macrosociology. The specific case study I develop is the possible state collapse in Saudi Arabia. . .

A manuscript submitted to the American Journal of Sociology.
A PDF of the article is here

See it posted on:

QuanHist.Reccurrent Archive

Other publications:

Turchin, Peter and Thomas D. Hall. 2003.

Spatial Synchrony among and within World-Systems: Insights from Theoretical Ecology.

Journal of World-Systems Research 9:37-66.

http://jwsr.ucr.edu/

archive/vol9/number1/pdf/jwsr-v9n1-turchinhall.pdf

Turchin, P. 2003. Secular waves in historical demography (in Russian).

Priroda 6: 3-12.

Peter Turchin's general web page: (with CV, other publications, etc):

here

This page was updated on March 23, 2005

June 12, 2005