Peter Turchin - Historical Dynamics: Why States Rise and Fall (Princeton Studies in Complexity, 26)

Historical Dynamics

Why States Rise and Fall

PRINCETON STUDIES IN COMPLEXITY

SERIES EDITORS

Philip W. Anderson (Princeton University); Joshua M. Epstein (The Brookings Institution); Duncan K. Foley (Barnard College); Simon A. Levin (Princeton University); Martin A. Nowak (Harvard University)

Lars-Erik Cederman, Emergent Actors in World Politics: How States and Nations Develop and Dissolve

Robert Axelrod, The Complexity of Cooperation: Agent-Based Models of Competition and Collaboration

Peter S. Albin, Barriers and Bounds to Rationality: Essays on Economic Complexity and Dynamics in Interactive Systems. Edited and with an introduction by Duncan K. Foley

Duncan J. Watts, Small Worlds: The Dynamics of Networks between Order and Randomness

Scott Camazine, Jean-Louis Deneubourg, Nigel R. Franks, James Sneyd, Guy Theraulaz, Eric Bonabeau, Self-Organization in Biological Systems

Peter Turchin, Historical Dynamics: Why States Rise and Fall

Historical Dynamics

Why States Rise and Fall

Peter Turchin

PRINCETON UNIVERSITY PRESS

PRINCETON AND OXFORD

Copyright 2003 by Princeton University Press

Published by Princeton University Press, 41 William Street,

Princeton, New Jersey 08540

In the United Kingdom: Princeton University Press, 6 Oxford Street,

Woodstock, Oxfordshire OX20 1TR

press.princeton.edu

All Rights Reserved

First published in 2003

First paperback printing, 2018

Paper ISBN 978-0-691-18077-9

Cloth ISBN: 978-0-691-11669-3

Library of Congress Control Number 2003110656

British Library Cataloging-in-Publication Data is available

The publisher would like to acknowledge Peter Turchin for providing the camera-ready copy from which this book was printed

Printed on acid-free paper.

Printed in the United States of America

10 9 8 7 6 5 4 3 2

Contents

List of Figures

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List of Tables

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Preface

Many historical processes are dynamic: growth and decline of populations, territorial expansion and contraction of empires, trends in political centralization/decentralization, and the spread of world religions, to name just a few examples. A general approach to studying dynamical systems is to advance rival hypotheses based on specific mechanisms, translate the hypotheses into mathematical models, and contrast model predictions with empirical patterns. Mathematical modeling is a key ingredient in this research program because quantitative dynamical phenomena, often affected by complex feedbacks, cannot be fully understood at a purely verbal level. Another important ingredient is the full use of statistical techniques (such as time-series analysis) for quantitative and rigorous comparison between model-predicted and observed patterns. This general approach has proved to be extremely successful in natural sciences. Can it be instrumental in increasing our understanding of historical processes?

Historical Dynamics is an attempt to answer this question. The specific problem chosen for analysis is the territorial dynamics of agrarian states. In other words, can we understand why some polities at certain times expand, while at other times they contract? The advantage of focusing on territorial expansion/contraction is that we have reasonably accurate empirical data on this aspect of historical dynamics (historical atlases). The focus on agrarian polities is motivated by the extent of empirical material (roughly, from the third millennium B.C.E. to 1800 C.E.) and the greater simplicity of these societies compared to modern ones, potentially making them easier to understand and model.

Although the main focus of the book is on territorial dynamics, it is clear that the ability (or inability) of states to expand depends very much on their internal characteristics. Thus, in order to understand how and why states expand and contract, we need to study military, economic, demographic, ethnological, and ideological aspects of social dynamics. I consider four sociological theories potentially explaining territorial dynamics. The first is the geopolitical model of Randall Collins. This theory has been very clearly formulated and requires minimal work to translate into a mathematical model. The second one, by contrast, is an original development. Starting from ideas of the fourteenth century Arabic thinker Ibn Khaldun and recent developments in sociobiology, I advance a theory attempting to explain why the capacity for collective action may vary among different societies. The third theory addresses the issue of ethnic assimilation/religious conversion dynamics. Finally, the fourth theory focuses on the interaction between population dynamics and sociopolitical stability. The connection between population growth and state breakdown is based on the demographic-structural model of Jack Goldstone (another well-formulated theory that is easily translated into a dynamical model). To this model, I add the feedback mechanism, postulating how state breakdown and resulting sociopolitical instability negatively affect population numbers. The four theories address somewhat different aspects of historical dynamics, and thus logically are not mutually exclusive. However, alternative hypotheses about particular empirical patterns can be derived from them and tested with data. I present several such empirical tests.

ACKNOWLEDGMENTS

Many people provided extensive comments on previous book drafts or draft chapters. I am particularly indebted to Tom Hall, Jack Goldstone, Sergey Nefedov, and the anonymous reviewer who read the whole draft and provided numerous and truly excellent comments and criticisms. I also wish to express my deep gratitude to Marc Artzrouni, Robert Boyd, Christopher Chase-Dunn, Randall Collins, Lev Ginzburg, Robert Hanneman, John Komlos, and Nikolai Rozov for their comments on various parts of previous drafts. Many thanks to Svetlana Borinskaya, Andrey Korotayev, and other members of the Social Evolution group in Moscow for constructive critique and general encouragement. I am grateful to Marc Artzrouni for providing the graphical output of his simulation model for . Finally, I wish to thank Jennifer Slater for excellent copyediting, Kathy Tebo for help with typing and proofreading, and Mirko Janc for his TeXpert typesetting.

Historical Dynamics

Why States Rise and Fall

Chapter One

Statement of the Problem

1.1 WHY DO WE NEED A MATHEMATICAL THEORY IN HISTORY?

Why do some politieschiefdoms and states of various kindsembark on a successful program of territorial expansion and become empires? Why do empires sooner or later collapse? Historians and sociologists offer a great variety of answers to these and related questions. These answers range from very specific explanations focusing on unique characteristics of one particular polity to quite general theories of social dynamics. There has always been much interest in understanding history, but recently the theoretical activity in this area has intensified (Rozov 1997). Historical sociology is attempting to become a theoretical, mature science.