Perspectives on transportation history

I view transport as a crucial structuring condition in society that is perhaps under-appreciated and under-studied. The extension of the Red Line from Harvard Square (its terminus when I was a graduate student) to Davis Square in Somerville a decade later illustrated the transformative power of a change in the availability of urban transportation; residential patterns, the creation of new businesses, and the transformation of the housing market all shifted rapidly once it was possible to get from Davis Square to downtown Boston for a few dollars and 30 minutes. The creation of networks of super-high-speed trains in Europe and Asia does the same for the context of continental-scale economic and cultural impacts. And the advent of container shipping in the 1950's permitted a substantial surge in the globalization of the economy by reducing the cost of delivery of products from producer to consumer. Containers were a disruptive technology. It is clear that transportation systems are a crucial part of the economic, political, and cultural history of a place larger than a village; and this is true at a full range of scales.

We can look at the history of transport from several perspectives. First, we can focus on the social imperatives (including cultural values) that have influence on the development and elaboration of a transportation system. (Frank Dobbin considers some of these factors in his Forging Industrial Policy: The United States, Britain, and France in the Railway Age, where he considers the substantial impact that differences in political culture had on the build-out of rail networks in France, Germany, and the United States; link.) Second, we can focus on the social and political consequences that flow from the development of a new transportation system. For example, ideas and diseases spread further and faster; new population centers arise; businesses develop closer relationships with each other over greater distances. And third, we can consider the historiography of the history of transport -- the underlying assumptions that have been made by various historians who have treated transport as an important historical phenomenon.

Over fifty years ago L. Girard treated these kinds of historical effects in his contribution to Cambridge Economic History of Europe: Volume VI (Parts I and II), Part I, in a chapter dedicated to "Transport". He provides attention to the main modalities of transport -- roads, sea, rail. In each case the technology and infrastructure are developed in ways that illustrate significant contingency. Consider his treatment of the development of the English road network.

Eventually the English network, the spontaneous product of local decisions, progressed out of this state of disorganization. Its isolated segments were linked up and ultimately provided a remarkably comprehensive network corresponding to basic national requirements. By trial and error and by comparing their processes, the trustees and their surveyors arrived at a general notion of what a road should be. (217) 

(Notice the parallels that exist between this description and the process through which the Internet was built out in the 1980s and 1990s.)

 Similar comments are offered about the American rail system.

The American railroad was the product of improvisation, in contrast to the English track, which was built with great care. At first all that was required was a fairly rough and ready line which could operate with a minimum amount of equipment. Then as traffic increased and profits began to be made, the whole enterprise was transformed to take account of the requirements of increased traffic and of the greater financial possibilities. (232)

Despite all their improvisations and wastage, the American railroads astonished Europe, which saw a whole continent come to life in the path of the lines. The railways opened up America for a second time. By 1850 the east-west link between western Europe and the Mississippi valley was already created by means of the States on the Atlantic seaboard. The supremacy of the Chicago-New York axis had become established, at the expense of the South and of Canada, which were taking more time to get organized. America swung away from a north-south to an east-west orientation. (233)

And here is a somewhat astounding claim:

The northern railways allowed the Union to triumph in the Civil War, which was fought in part to determine the general direction to be taken by the future railways. (233-234)

Also surprising is the role that Girard attributes to the politics of railroads in the ascendancy of Napoleon III in 1851 (239).

Here is Girard's summary of the large contours of the development of transport during this critical period:

Whatever the course of future history, the century of the railway and the steamer marks a decisive period in the history of transport, and that of the world. Particular events in political history often tend to assume less and less importance as time goes on. But the prophecies of Saint-Simon on the unification of the planet, and the meeting of the races for better or for worse, remain excitingly topical. Man has changed the world, and the world has changed man -- in a very short time indeed. (273)

This history was written in 1965, over fifty years ago. One thing that strikes the contemporary reader is how disinterested the author appears to be in cause and effect. He does not devote much effort to the question, what forces drove the discoveries and investments that resulted in a world-wide network of railways and steamships? And he does not consider in any substantial detail the effects of this massive transformation of activities at a national and global scale. Further, Gerard gives no indication of interest in the social context or setting of transport -- how transport interacted with ordinary people, how it altered the environment of everyday life, how it contributed to social problems and social solutions. It seems reasonable to believe that the history of transport during this period would be written very differently today.

(Prior posts have given attention to transport as a causal factor in history; link.)

River warfare in the US Civil War

The mental images that most Americans have of the American Civil War involve the scenes of major land battles -- Bull Run, Antietam, Gettysburg. Armies marched dozens of miles, prepared encampments and defensive works, and either attacked the enemy in its own prepared defenses or awaited contact with the enemy. The picture is Napoleonic: an army marching across terrain to fight other slow-moving armies.

It is therefore highly interesting to realize that naval warfare on rivers -- especially the Mississippi River -- played a key role in the success of Union forces in 1862-1865, and that armored steamships were critical to victory. To an extent that is now hard to imagine, with modern transportation networks including dense highway networks, as well as air and rail systems, how important control and navigation of the Mississippi River was to both Union and Confederate war fighting. General Ulysses S. Grant's strategy for bringing the war to the South was dependent on the objective of gaining control of the Mississippi River; and the river was a key component in the movements of troops, supplies, and field headquarters around the contested territories.

maps: Feis, Grant's Secret Service, p. 12

The reason for this importance of control of the Mississippi has to do with speed of deployment and logistics. (There was also a major economic consideration: if the South could close the Mississippi, it would cause great hardship for the Northern population.) But consider the logistics and speed issues. The speed of advance of an army on the march through water-logged terrain with poor roads -- conditions that obtained during much of Grant's campaign in the west -- was minuscule in comparison to a steamship moving unhindered several hundred miles along the river. As a rough estimate, it would take an army 21 days to march from Cairo, Illinois to Vicksburg, Mississippi, whereas it would take a steam-powered riverboat about three days to travel the same distance. And steamships could carry all the materiel required for the campaign. (Travel up-river the same distance would take longer.) Maintaining a supply line for the mountains of food, horse fodder, ammunition, replacement equipment, and evacuation of the wounded required by an army in the field depended on heavy transport -- by rail or river boat. Rail transport was substantially faster than riverboat transport -- the average rail speed unhindered by sabotage of tracks, etc. was 25 mph, compared to 5-7 mph for river transport. So rail transport was preferable. However, controlling and maintaining rail networks in hostile territory was extremely difficult, since local sympathizers could sabotage tracks and bridges in dozens of remote places. As a result, naval operations were a key part of the Union's war fighting in the west of the country. The Mississippi River represented the great north-south highway along which the war in the west was fought.

The strategic importance of strong fortifications with heavy guns at locations along the river permitting control of traffic was plain to all sides; so major battles developed involving attempts to seize fortified places like Vicksburg, Mississippi. Grant's persistent effort to besiege and occupy Vicksburg was a mark of his strength as a general, and the eventual success of his plans represented a turning point in the Civil War. But key to success at Vicksburg (and Fort Henry a year earlier) was the availability of a growing force of river warships, from lightly armed gunboats to ironclad and timber-clad steamships with heavy armaments capable of assaulting land-based fortifications. And almost none of this range of river craft existed before the onset of war. The use armored river steamboats of the Civil War thus represented a major technological shift in warfare -- perhaps as dramatic in 1861 as high-precision artillery has been in Ukraine in 2022.

The high end of these armored vessels were the City-class gunboats ("turtles"). These were ironclad vessels designed for service in rivers rather than open seas. They had shallow draft of six feet, were armed with thirteen guns, and could cruise at eight knots. Seven boats were delivered by January, 1862, and they played a significant role in major battles along the Mississippi River, including Vicksburg. These ships included the USS Baron DeKalb, Cairo, Carondelet, Cincinnati, Louisville, Mound City, and Pittsburgh.

Complementing these ironclads was a larger group of wooden vessels that also played a major role in river warfare during the Civil War. Angus Konstam's book Mississippi River Gunboats of the American Civil War 1861-65 provides a review of the rapid development of armored wooden gunboats as the war in the west heated up. These craft needed to be shallow-draft, and they needed to be maneuverable enough to manage the twisting courses of the midwestern rivers. They were steam-powered and relatively slow, but provided both heavy mobile armaments and heavy transport for the strategic thrusts of the army. They could be used to transport troops, and they therefore permitted rapid shifts in the location of land-based attacks.

A rapid effort at ship-building and conversion ensued by both Confederate and Union militaries after the outbreak of war, and within a year each side had a number of river-based warships. The earliest heavy gunboats in the Union arsenal were converted commercial vessels -- the Conestoga (572 tons), the Lexington (362 tons), and the Tyler (420 tons), launched in summer 1861 and shielded with thick timber. In addition to the heavy gunboats, the armies also needed a larger number of smaller river gunboats (150-250 tons) that could be used to patrol the river and serve as transport up and down the river (9). The flagship of the river navy, also converted from commercial use, was the USS Black Hawk (902 tons). (All these data are drawn from Konstam's table of ships operated by both sides.) These wooden river warships were immediately thrown into the struggle.

What emerged was a campaign involving the attack on these Confederate naval and riverside defenses by two fleets: One descending the river from Cairo, Illinois, and the other (after the fall of New Orleans in April 1862) working its way up from the Gulf of Mexico. After a brilliantly executed attack on Fort Henry and Fort Donelson [by forces commanded by Grant] on the Tennessee and Cumberland Rivers, Union naval forces in the upper Mississippi faced a series of imposing fortifications. (Konstam, 5)

Fortifications and heavy guns at Vicksburg were the most significant of these Confederate capabilities on the Mississippi River, and it took great fortitude for army and naval forces to eventually take Vicksburg in July 1863. This represented a major turning point in the Civil War.

What is particularly interesting to me about this quick exposure to river warfare in the 1860s is the fact that there were several tempos of operations in the Civil War -- the movements of armies at 15-20 miles per day, the movements of troops, officers, and materiel by steamship at perhaps 100 miles per day and by rail when available at 400 miles per day, and the transmission of messages at Internet speed by telegraph. The faster pace of steamboat and rail warfare fundamentally changed the challenges and opportunities confronting the generals. It is plain, then, that the American Civil War was a high-tech war, with innovations and adaptations introduced into war fighting in real time. (Even the evolution of heavy weaponry and ammunition moved forward quickly during the five years of fighting.) Here again, the similarity to the Ukraine war is striking.

(Here is an interesting photo essay on the evolution of Civil War gunboats; link. And here is a National Parks historical video on the battle of Vicksburg; link.)

Why spatial analysis?

G. William Skinner's contributions to the China field were many (link). A great deal of current research in the China field builds on his regionalization theories. Key concepts like core-periphery structure, macroregions, transport costs, the questionable relevance of political boundaries, and economic integration implying social and cultural integration are all ideas that Skinner developed and that have been utilized in remarkably insightful ways by several cohorts of China scholars.

Other of Skinner's contributions might be mentioned with especial emphasis: his treatments of urban place and city hierarchies and micro-demographic and family patterns are relevant in particular.

But the central insight that has had greatest impact is the spatial ordering of social life created by transport and marketing. And Skinner's fundamental idea is that China's geography is better understood as a set of macroregions rather than provinces. Economic geography is more fundamental than political jurisdictions.

So it is worth asking to begin: what motivates and justifies this approach? The ideas are now common currency in China studies, but perhaps the rationale is less well remembered. What are the social mechanisms that work to create the dynamic and stable patterns Skinner hypothesizes? What concrete social processes work to create the core-periphery patterns that underlie the macroregions theory?

Transport cost, and the enormous efficiency of water transport, is particularly fundamental in Skinner's analysis of Ming-Qing China, as it was for Mark Elvin as well. China's system of navigable rivers and canals made some regions much more accessible to each other than others. And population followed this fact. (A recent trip to Hubei reinforced this fact to me: visiting the rugged terrain of Wudang Mountain made it very clear how extraordinarily difficult it was to transport heavy materials across China using traditional technologies and pre-modern roads.)

Soil fertility and agricultural productivity are related factors. High fertility supports dense population -- hence "core" defined in terms of population density. And fertility is related to rivers. Flood plains have natural advantages when it comes to agriculture. But fertility is related to social factors as well. High population density yields fertilizer in the form of night soil. It also creates demand, as Skinner observed, for fuel, which led to a transfer of nutrients from periphery to core. And agriculture is responsive to investment in infrastructure -- roads, irrigation, water management systems. But these investments are easier to gain in high density populations. This all implies a couple of important feedback loops: density =>; rising agricultural productivity => rising density.

What about the periphery regions? They lack water transport; there is less economic demand for roads; agricultural productivity is low; and peripheries are generally difficult for states to penetrate with civil and military force. So bandits, rebels, and anarchists can loiter there in reasonable comfort.

There is another aspect related to this last factor. Skinner pays less attention to it, but Jim Scott has made it a centerpiece of his recent thinking. This is the dynamic of agrarian state extension from fertile core to barren periphery (or highlands). Scott's analysis of Zomia is precisely a treatment of far periphery (link).

What are the social consequences of this dynamic process over time? There are many, but here are a few:

• Patterns of diffusion of ideas, movements, and goods. 
• High barriers to state intervention in some places but not others. 
• Separation of elite and plebeian cultures. 
• And researchers have explored some of these dynamics with respect to topics ranging from the Chinese Revolution to technology change in agriculture. 

Why is spatial analysis important?  This framework of research places the spotlight on interactions between place and activity.  These substantive theories and frameworks have proven to be enormously constructive in the development of Chinese history in the past 30 years.

Technology in the ancient world: time

We don't think of the ancient world as being one that was rich in technological innovation or progress. And yet in a number of areas, there were very significant developments in technology -- in ships, mining, fortification, siege engines, road-building, and bridges and aqueducts, for example. And there is the intriguing example of the Antikythera mechanism (link), dating from the first century BCE and lacking a clear technological context, but establishing firmly the availability of advanced metal-working techniques and complex geared mechanisms. (Two fascinating videos are linked on the earlier blogpost on the Antikythera mechanism.) 

John Peter Oleson's The Oxford Handbook of Engineering and Technology in the Classical World provides an extensive survey of the current state of knowledge about the topic, drawing upon the work of dozens of experts in classical scholarship. Here is the table of contents of the volume, from which the reader can get a very good idea of the topics and technologies considered:

Part I Sources  

1. Ancient Written Sources for Engineering and Technology, Serafina Cuomo  2. Representations of Technical Processes, Roger Ulrich  3. Historiography and Theoretical Approaches, Kevin Greene  

Part II Primary, Extractive Technologies  

4. Mining and Metallurgy, Paul T. Craddock  5. Quarrying and Stoneworking, J. Clayton Fant  6. Sources of Energy and Exploitation of Power, Orjan Wikander  7. Greek and Roman Agriculture, Evi Margaritis and Martin K. Jones  8. Animal Husbandry, Hunting, Fishing, and Fish Production, Geoffrey Kron 

Part III Engineering and Complex Machines  

9. Greek Engineering and Construction, Fredrick A. Cooper  10. Roman Engineering and Construction, Lynne Lancaster  11. Hydraulic Engineering and Water Supply, Andrew I. Wilson  12. Tunnels and Canals, Klaus Grewe  13. Machines in Greek and Roman Technology, Andrew I. Wilson  

Part IV Secondary Processes and Manufacturing  

14. Food Processing and Preparation, Robert I. Curtis  15. Large-Scale Manufacturing, Standardization, and Trade, Andrew I. Wilson  16. Metalworking and Tools, Carol Mattusch  17. Woodworking, Roger B. Ulrich  18. Textile Production, John P. Wild  19. Tanning and Leather, Carol van Driel-Murray  20. Ceramic Production, Mark Jackson and Kevin Greene  21. Glass Production, E. Marianne Stern 

Part V Technologies of Movement and Transport  

22. Land Transport, Part 1: Roads and Bridges, Lorenzo Quilici  23. Land Transport, Part 2: Riding, Harnesses, and Vehicles, Georges Raepsaet  24. Sea Transport, Part 1: Ships and Navigation, Sean McGrail  25. Sea Transport, Part 2: Harbors, David J. Blackman  

Part VI Technologies of Death  

26. Greek Warfare and Fortification, Philip de Souza  27. Roman Warfare and Fortification, Gwyn Davies  

Part VII Technologies of the Mind  

28. Information Technologies: Writing, Book Production, and the Role of Literacy, Willy Clarysse and Katelijn Vandorpe  29. Timekeeping, Robert Hannah  30. Technologies of Calculation, Part 1: Weights and Measures (Charlotte Wikander), Part 2: Coinage (Andrew Meadows), Part 3: Practical Mathematics (Karin Tybjerg) 31. Gadgets and Scientific Instruments, Orjan Wikander  32. Inventors, Invention, and Attitudes toward Innovation, Kevin Greene

Part VIII Ancient Technologies in the Modern World  

33. Expanding Ethnoarchaeology: Historical Evidence  and Model-Building in the Study of Technological Change, Michael B. Schiffer  

Many of the technologies described here are important and interesting, but familiar: ships, mines, fortifications, and other common interactions with the natural world. The most surprising technology innovations are described in Part VII, "Technologies of the Mind", and here there is more information about "high technology" in the ancient world. Orjan Wikander describes "gadgets and instruments" in chapter 31, which is a topic that sheds more light on advanced technical and scientific innovation -- and therefore provides some intellectual background for the design and fabrication of the Antikythera mechanism. What is most eye-opening about the details of the Antikythera mechanism is the intricate design of the gearing system that it embodied and the advanced metal-working techniques that it presupposed for fabrication (cutting precision gear wheels and most puzzling, cutting concentric tubes to convey motion from one gear assembly to an output ring). Wikander makes it clear that the principle of geared machines was familiar in the Hellenistic world (for advanced mathematicians and philosophers, at least). Field and Wright report on a Byzantine sundial calendar geared device dating from about 500 AD, whose gears are very similar to those used in the Antikythera device; link. They take this as evidence of an ongoing engineering tradition in the Greek world of fabrication of geared devices. (Notably, the sundial calendar is substantially less complex than the Antikythera mechanism, implying a loss of technological knowledge over the intervening 500 years.) 

But there is an interesting complication about these high-tech astronomical devices for the history of technology: these devices were advanced and sophisticated, but they appear to have had little practical utility. It appears to be widely agreed, for example, that the Antikythera device had no use as a navigational instrument; instead, it appears to be an entertaining demonstration of astronomical knowledge for an elite audience. A more useful geared instrument, apparently, was the "hodometer", a wheeled and geared device that could be pulled along a route and used to measure distance. But this is an important guidepost in the study of the history of technology: the innovation and development of the "gadget" itself does not ensure its proliferation and widespread adoption. It needs to find a need within ambient society to which the gadget can be adapted in a useful way.

An interesting challenge of measurement in the ancient world was time. Robert Hannah's chapter on "Timekeeping" provides a very interesting account of shifts in both the conception of time and the means that were available or developed to measure its passage. It is evident that it is not possible to engage in the science of mechanics without a way of measuring equal intervals of time -- key variables like velocity, acceleration, inertia all require an account of distance covered per unit of time. Most fundamentally, it isn't possible to form the concept of velocity unless one has a fairly definite conception of units of time. "Fast" and "slow" are imaginable; but 4 m/s is not. 

A little bit of reflection will show that there are at least two different problems encompassed under "timekeeping". First, we may have reasons for wanting to know "what is the time of day at the moment?", by which we mean, most fundamentally, how long past sunrise (or before sunset) is it currently? And how long until dinner? In this context it is very interesting (and eyebrow-raising) to learn of "unequal hours" involved in Greek timekeeping:

Sundials helped inculcate into society the concept of the seasonal, or unequal, hour. For most purposes in antiquity, such hours were the norm. From Egypt came the notion that each day or night could be divided into 12 hours from sunrise to sunset, and another 12 from sunset to sunrise (Parker 1974: 53; Quirke 2001: 42). Since daytime and nighttime change in length with the seasons, the length of each hour therefore changed also according to the season. Only at the spring and autumn equinoxes were the hours equal through the whole day. (p. 749)

So a person's pulse (beats per sixtieth of an hour) will be different, depending on whether it is measured in daytime or nighttime. Suppose the individual's real pulse rate at equinox is 70 beats per sixtieth of an hour and it never changes. When measured on December 22 by counting beats for an hour and dividing by 60, his/her pulse will be 54 bpm; the same measurement on June 22 results in a pulse of 86 bpm. Further, length of day is influenced by latitude as well as season; so the same individual would have a different pulse rate in Miami than in Helsinki, on the same day. Measuring pulse by such a system is useless as a tool for assessing health status. And how about cooking -- what is the result of a variable hour for a 4-minute soft-boiled egg? 

The harder challenge of time measurement is the problem of measuring "duration of time" -- how many minutes it takes to walk from the agora to the Acropolis in Athens, how long it takes the arrow to fly from the archer to the target, how long the egg has been boiling. The problem of time-telling can be handled reasonably well by use of a sundial (during daylight hours) and by the position and elevation of the stars by night, but a sundial is not a practical instrument for measuring duration.

What is needed for measuring duration is an absolute measure of "equal interval of time" that can be used to measure duration -- ticks of a clock, swings of a pendulum of a certain length, vibration of a cesium atom, movement of a violin string tuned to E, movement of the fork of a tuning fork tuned to A. More exactly, what is needed is a process that occurs in the same period of time every time it is invoked; and a way of counting the number of times the event has occurred during the process to be measured. Each of the processes mentioned here identifies a discrete event that always takes the same amount of time from beginning to end. The difficult challenge is an automatic way of counting events. Mechanical clocks "count" events by advancing a geared mechanism, moving pointers on a dial. 

The water clock (clepsydra) and sand clock both served to measure duration through the idea that the flow of a liquid or viscous substance through a constrained opening takes a regular amount of time. So a bucket with a hole in the bottom was used to measure the period in which legal arguments needed to be made in Athenian proceedings (752).

Here is a novel clock mechanism that could have been used. Suppose we construct a 6.21013-meter pendulum. It has a period of 5.0 seconds. This solves the first part of the problem: an event that always takes the same amount of time. But how to count events in order to measure extended periods of time? Suppose we design a simple device in which a small bucket with volume of 10 cm^3 is fitted to a lever and is triggered by a tap of the pendulum. It empties into a calibrated glass vessel and is refilled automatically in the next several seconds. After the first cycle the calibrated vessel contains 10 cm^3; after 50 cycles the vessel contains 500 cm^3 of water and 250 seconds have elapsed. After 17,280 cycles the calibrated vessel contains 172,800 cm^3 of water (172.8 liters), and 24 hours have elapsed. The calibration of the vessel permits the user to measure the amount of time (number of swings of the pendulum) that have occurred since beginning the process, by measuring the volume of the water. A large vessel (200 liters) will permit measurement of periods extending over a full 24 hour period; a narrow vessel can be calibrated to permit precise measurement of short intervals (5 minutes). The clock will be precise to the range of 5 seconds -- perfectly sufficient for boiling 4-minute eggs. And the precision of the timepiece can be increased by shortening the pendulum; a .5 meter pendulum has a period of 1.42 seconds.

(In this example the clock was initiated at midnight, and the level of the water indicates that the time is now 10:00 am.)

(Who can direct me to the Agora patent office? All royalties will be directed to the defense fund established on behalf of Professor Socrates.)

Once we have a system for measuring intervals of time, it is possible to define and measure other important physical quantities: velocity, acceleration, the period of a pendulum, the frequency of a vibrating string, a mammal's pulse. So measurement of mid-range intervals of time is crucial to the development of physics and mechanics as well as other areas of science -- as is evident from the Renaissance scientists such as Galileo. Conversely, without such a system of time-interval measurement, many important physical laws cannot be discovered. Ancient Greek and Roman scientists had reasonably effective instruments for measuring distance, and only very limited instruments for measure elapsed time. Time on the scale of a month or a year could be measured by observation of the movements of the moon and the planets; but time on the scale of seconds and minutes could not be measured by these means.

(Wikander is best known for his research on water technologies, including especially water mills. Here is an interesting page outlining changing knowledge over the past several decades on the extent of use of water mills during the classical period (link).)

Slime mold intelligence

We often think of intelligent action in terms of a number of ideas: goal-directedness, belief acquisition, planning, prioritization of needs and wants, oversight and management of bodily behavior, and weighting of risks and benefits of alternative courses of action. These assumptions presuppose the existence of the rational subject who actively orchestrates goals, beliefs, and priorities into an intelligent plan of action. (Here is a series of posts on "rational life plans"; link, link, link.)

It is interesting to discover that some simple adaptive systems apparently embody an ability to modify behavior so as to achieve a specific goal without possessing a number of these cognitive and computational functions. These systems seem to embody some kind of cross-temporal intelligence. An example that is worth considering is the spatial and logistical capabilities of the slime mold. A slime mold is a multi-cellular "organism" consisting of large numbers of independent cells without a central control function or nervous system. It is perhaps more accurate to refer to the population as a colony rather than an organism. Nonetheless the slime mold has a remarkable ability to seek out and "optimize" access to food sources in the environment through the creation of a dynamic network of tubules established through space.

The slime mold lacks beliefs, it lacks a central cognitive function or executive function, it lacks "memory" -- and yet the organism (colony?) achieves a surprising level of efficiency in exploring and exploiting the food environment that surrounds it. Researchers have used slime molds to simulate the structure of logistical networks (rail and road networks, telephone and data networks), and the results are striking. A slime mold colony appear to be "intelligent" in performing the task of efficiently discovering and exploiting food sources in the environment in which it finds itself.

One of the earliest explorations of this parallel between biological networks and human-designed networks was Tero et al, "Rules for Biologically Inspired Adaptive Network Design" in Science in 2010 (link). Here is the abstract of their article:

Abstract Transport networks are ubiquitous in both social and biological systems. Robust network performance involves a complex trade-off involving cost, transport efficiency, and fault tolerance. Biological networks have been honed by many cycles of evolutionary selection pressure and are likely to yield reasonable solutions to such combinatorial optimization problems. Furthermore, they develop without centralized control and may represent a readily scalable solution for growing networks in general. We show that the slime mold Physarum polycephalum forms networks with comparable efficiency, fault tolerance, and cost to those of real-world infrastructure networks—in this case, the Tokyo rail system. The core mechanisms needed for adaptive network formation can be captured in a biologically inspired mathematical model that may be useful to guide network construction in other domains.

Their conclusion is this:

Overall, we conclude that the Physarum networks showed characteristics similar to those of the [Japanese] rail network in terms of cost, transport efficiency, and fault tolerance. However, the Physarum networks self-organized without centralized control or explicit global information by a process of selective reinforcement of preferred routes and simultaneous removal of redundant connections. (441)

They attempt to uncover the mechanism through which this selective reinforcement of routes takes place, using a simulation "based on feedback loops between the thickness of each tube and internal protoplasmic flow in which high rates of streaming stimulate an increase in tube diameter, whereas tubes tend to decline at low flow rates" (441). The simulation is successful in approximately reproducing the observable dynamics of evolution of the slime mold networks. Here is their summary of the simulation:

Our biologically inspired mathematical model can capture the basic dynamics of network adaptability through iteration of local rules and produces solutions with properties comparable or better than those real-world infrastructure networks. Furthermore, the model has a number of tunable parameters that allow adjustment of the benefit-cost ratio to increase specific features, such as fault tolerance or transport efficiency, while keeping costs low. Such a model may provide a useful starting point to improve routing protocols and topology control for self-organized networks such as remote sensor arrays, mobile ad hoc networks, or wireless mesh networks. (442)

Here is a summary description of what we might describe as the "spatial problem-solving abilities" of the slime mold based on this research by Katherine Harman in a Scientific American blog post (link):

Like the humans behind a constructed network, the organism is interested in saving costs while maximizing utility. In fact, the researchers wrote that this slimy single-celled amoeboid can "find the shortest path through a maze or connect different arrays of food sources in an efficient manner with low total length yet short average minimum distances between pairs of food sources, with a high degree of fault tolerance to accidental disconnection"—and all without the benefit of "centralized control or explicit global information." In other words, it can build highly efficient connective networks without the help of a planning board.

This research has several noteworthy features. First, it seems to provide a satisfactory account of the mechanism through which slime mold "network design intelligence" is achieved. Second, the explanation depends only on locally embodied responses at the local level, without needing to appeal to any sort of central coordination or calculation. The process is entirely myopic and locally embodied, and the "global intelligence" of the colony is entirely generated by the locally embodied action states of the individual mold cells. And finally, the simulation appears to offer resources for solving real problems of network design, without the trouble of sending out a swarm of slime mold colonies to work out the most efficient array of connectors.

We might summarize this level of slime-mold intelligence as being captured by:

• trial-and-error extension of lines of exploration
• localized feedback on results of a given line leading to increase/decrease of the volume of that line

This system is decentralized and myopic with no ability to plan over time and no "over-the-horizon" vision of potential gains from new lines of exploration. In these respects slime-mold intelligence has a lot in common with the evolution of species in a given ecological environment. It is an example of "climbing Mt. Improbable" involving random variation and selection based on a single parameter (volume of flow rather than reproductive fitness). If this is a valid analogy, then we might be led to expect that the slime mold is capable of finding local optima in network design but not global optima. (Or the slime colony may avoid this trap by being able to fully explore the space of network configurations over time.) What the myopia of this process precludes is the possibility of strategic action and planning -- absorbing sacrifices at an early part of the process in order to achieve greater gains later in the process. Slime molds would not be very good at chess, Go, or war.

I've been tempted to offer the example of slime mold intelligence as a description of several important social processes apparently involving collective intentionality: corporate behavior and discovery of pharmaceuticals (link) and the aggregate behavior of large government agencies (link).

On pharmaceutical companies:

So here's the question for consideration here: what if we attempted to model the system of population, disease, and the pharmaceutical industry by representing pharma and its multiple research and discovery units as the slime organism and the disease space as a set of disease populations with different profitability characteristics? Would we see a major concentration of pharma slime around a few high-frequency, high profit disease-drug pairs? Would we see substantial under-investment of pharma slime on low frequency low profit "orphan" disease populations? And would we see hyper-concentrations around diseases whose incidence is responsive to marketing and diagnostic standards? (link)

On the "intelligence" of firms and agencies:

But it is perfectly plain that the behavior of functional units within agencies are only loosely controlled by the will of the executive. This does not mean that executives have no control over the activities and priorities of subordinate units. But it does reflect a simple and unavoidable fact about large organizations. An organization is more like a slime mold than it is like a control algorithm in a factory. (link)

In each instance the analogy works best when we emphasize the relative weakness of central strategic control (executives) and the solution-seeking activities of local units. But of course there is a substantial degree of executive involvement in both private and public organizations -- not fully effective, not algorithmic, but present nonetheless. So the analogy is imperfect. It might be more accurate to say that the behavior of large complex organizations incorporates both imperfect central executive control and the activities of local units with myopic search capabilities coupled with feedback mechanisms. The resulting behavior of such a system will not look at all like the idealized business-school model of "fully implemented rational business plans", but it will also not look like a purely localized resource-maximizing network of activities.

******

Here is a very interesting set of course notes in which Prof. Donglei Du from the University of New Brunswick sets the terms for a computational and heuristic solution to a similar set of logistics problems. Du asks his students to consider the optimal locations of warehouses to supply retailers in multiple locations; link. Here is how Du formulates the problem:

*     Assuming that plants and retailer locations are fixed, we concentrate on the following strategic decisions in terms of warehouses.

• Pick the optimal number, location, and size of warehouses 
• Determine optimal sourcing strategy
• Which plant/vendor should produce which product 
• Determine best distribution channels
• Which warehouses should service which retailers

The objective is to design or reconfigure the logistics network so as to minimize annual system-wide costs, including

• Production/ purchasing costs
• Inventory carrying costs, and facility costs (handling and fixed costs)
• Transportation costs

As Du demonstrates, the mathematics involved in an exact solution are challenging, and become rapidly more difficult as the number of nodes increases.

Even though this example looks rather similar to the rail system example above, it is difficult to see how it might be modeled using a slime mold colony. The challenge seems to be that the optimization problem here is the question of placement of nodes (warehouses) rather than placement of routes (tubules).

Regional interconnectedness

Chicago, Milwaukee, and Detroit are part of a large economic region in the upper Midwest of the United States, which is sometimes referred to as the Great Lakes Region. There are hundreds of lesser cities within this regional system -- Erie, Toledo, Rockford, Grand Rapids, .... What are the economic interdependencies that exist among these cities? How important are these relationships in the overall pattern of economic development that each city demonstrates? And of critical practical importance, how much leverage exists for development planners in these major cities to enhance their city's progress through adroit use of these relationships? Is there a possible gain for Milwaukee in virtue of the net effect of its relationships to Detroit? Or is each metropolitan region mostly autarkic with respect to the other?

There seem to be several theoretical possibilities. One is that there are in fact major point-to-point economic interdependencies among cities within a large economic region and that these are significantly different across different pairs of cities. It might be that the growth or contraction of auto manufacturing in Detroit is tightly enough linked to supplier companies in Milwaukee that what helps Detroit also helps Milwaukee.

Another possibility is that the regional impact is systemic rather than point-to-point. Here the idea is that the great metropolitan regions within a regional economy contribute to the macroeconomic environment for the region -- labor demand, growth, consumer demand, and fiscal shares. The region sets the basic parameters -- transport cost, commodity prices, and the current distribution of population and talent. But the impact of, say, Milwaukee on Toledo is entirely mediated through the macroeconomic environment of the region. And to the extent that there are correlations of advance and decline, this is the result of regional "pulsing" of macroeconomic factors rather than specific city-to-city interactions.

A third possibility is that each metropolitan region is largely independent within the larger region, so that regional economic performance is simply the aggregation of the performance of the component metropolitan regions (cities). And if this is the case, then we would expect a low degree of correlation on economic development across the cities of a region. (But in this case it is more difficult to explain why we refer to the set of cities as an economic "region" at all, since this term implies a degree of economic similarity and interdependence.)

Let's look at the first possibility more closely. Logically, the possibility of this kind of interdependency appears to depend on the existence of directed flows of activities between the places that do not extend to other places. There must be some network reality to the region within which A and B are proximate nodes. What else could provide the mechanism of mutual causal influence upon which the postulated interdependence depends?

So what are the inter-city connections that might support tight point-to-point linkages? The direct industry-to-industry dependencies mentioned above are most obvious. More furniture manufacturing in Grand Rapids might stimulate a surge in business for the plastic mesh producers in Rockford, to complete those great Aeron chairs. The input-output tables measuring exchange activity between the two cities might be extensive or minimal.

Here is another possible connection -- the talent needs in some cities might lead to the growth of universities in cities in other parts of the region. In a hypothetical history of the Midwest, Chicago might extend its current concentration of research universities and become a "knowledge center" for the region, supplying the inventors, architects, accountants, and lawyers for the region. In fact, specialized education and research is more diffused than this; but isn't this essentially the role that Boston played for a century or so for the northeast?

A third possibility -- two cities might be tightly linked through the existence of particularly efficient transportation or communication systems between them. Are Seattle and San Francisco more tightly linked economically because they are both Pacific Ocean ports with low-cost transport between them? What about Minneapolis, St. Louis, and New Orleans, linked by the barges of the Mississippi River?

Historically there are fairly good measures of economic interconnectedness between places. We can examine the correlation of time series of prices, wages, and profits to measure the degree of economic integration that exists among A, B, and C. Likewise, we can examine the patterns of growth or contraction of employment over time; do Milwaukee, Toledo, and Detroit demonstrate synchronized patterns of growth and contraction in business activity and overall employment over long periods of time? And the transport links mentioned here are a particularly fundamental source of economic integration in 19th-century studies of China, France, or the United States. (It's possible that contemporary data would suggest that all U.S. cities are equally integrated by these measures, since market integration has increased dramatically through transport and communications improvements.)

The most compact basis for studies of regional integration derives from the original insights of central place theory -- William Cronon's analysis of Chicago and its hinterlands, Nature's Metropolis: Chicago and the Great West, is an outstanding example of this approach. And G. William Skinner's analysis of the urban hierarchies of late imperial China falls in this general approach. What these examples do not permit, though, is analysis of inter-city dependencies across a region. At a very different level, these are the kinds of questions Saskia Sassen is asking about "world" cities. She attempts to identify the linkages that exist among major cities with respect to financial flows, internet traffic, and telephone calls. See earlier posts on each of these approaches (post, post, post).

How does transportation function as a mid-range social cause?

Transportation systems function to move people, goods, and ideas. Rail systems, road networks, airline systems, and water transport provide links between places that permit more reliable and low-cost movement of people and goods from point to point than previously available. The history of transportation is simultaneously a history of technology change, population movement, colonialism, economic growth, business development, and the spread of disease.

Transportation systems are particularly interesting when we consider their capacity for conveying social causation. Consider these examples of causal relations mediated by transportation systems:

• Extension of a rail network stimulates the growth of new towns, villages and cities in North America in the 1880s.
• Establishment of a direct air travel link between A and B causes the more rapid spread of disease between these locations.
• Breakdown of the administration of the rail system leads to logistics bottlenecks and military defeat of the French army in the Franco-Prussian War.
• Regular river travel throughout the Canton Delta in China leads to the rapid spread of revolutionary ideas during the Republican Revolution, as travelers and merchants move easily from place to place.
• Commodity price correlation increases between Chicago and New York as a result of regular and cheap rail transport between these two cities.
• New business institutions (grain futures markets and grain elevators) are created to take advantage of cheap regular rail transport (Nature's Metropolis: Chicago and the Great West).
  

Examples can be multiplied. But the central point is that transportation is a robust causal mechanism that mediates many important social processes and outcomes. And its causal effectiveness is fairly transparent: new transportation opportunities create new options for social actors, who take advantage of these opportunities in choosing a place to live and work, in pursuing political goals, in moving armies, and in generating income. So transportation is a causal mechanism whose microfoundations are especially visible, and whose causal consequences are often very large.

(See "Transportation as a Large Causal Factor" for more on this subject.)

Skinner's spatial imagination

images: presentations of Skinner's data by Center for Geographic Analysis, Harvard University, AAS 2010

G. William Skinner was a remarkably generous scholar who inspired and assisted several generations of China specialists.  (Here is a link to a remembrance of Bill.)  He was prolific and fertile, and there is much to learn from rereading his work. There is quite a corpus of unpublished work in the form of research reports and conference papers.  Rereading this work is profoundly stimulating. It holds up very well as a source of ideas about social science analysis of concrete historical and social data, and there are many avenues of research that remain to be further explored.

Skinner is best known for his efforts to provide regional systems analysis of spatial patterns in China.   He thought of a social-economic region as a system of flows of people, goods, and ideas.  He argued for the crucial role that water transport played in knitting together the economic activities of a region in the circumstances of pre-modern transport.   

Skinner's work demonstrated the great value of spatial analysis.  Patterns emerge visually once we’ve selected the appropriate level of scope.  Mapping social and economic data is tremendously insightful.  He was also highly sensitive to the social and cultural consequences of these flows of activity.  For example, patterns of gender ratios show a pronounced regional pattern; Skinner demonstrates the relevance of core-periphery structure to social-cultural variables such as this one. 

Skinner plainly anticipated the historical GIS revolution conceptually.  And this is a feature of imagination, not technology.

A classic series of articles on the spatial structure of the Chinese countryside in the 1960s provided an important basis for rethinking “village” society. They also provided a rigorous application of central place theory to the concrete specificity of China.  Here are several maps drawn from these essays ("Marketing and Social Structure in Rural China." Journal of Asian Studies 24 (1-3), 1964-65). Here Skinner is trying out the theories of central place theory, and the theoretical prediction of economic space being structured as a system of nested hexagons with places linked by roads.

Another key contribution of Skinner's work is his analysis of China in terms of a set of eight or nine “macroregions”.  He argues that China was not a single national economic system, and it was not a set of separate provincial economies.  Instead, it consisted of a small number of “macroregions” of trade, commerce, and population activity, linked by water transport.  And macroregions were internally differentiated into core and periphery.  

Skinner used meticulous county-level databases to map the economic and demographic boundaries of the region.  Skinner identified core and periphery in terms of population density, agricultural use, and other key variables.  And he then measured a host of other variables – female literacy, for example – and showed that these vary systemically from core to periphery.  There is also an important ecological dimension to the argument; Skinner demonstrated that there is a flow of fertility from periphery to core as a result of the transfer of food and fuel from forests to urban cores.  (This analysis is developed in "Regional Urbanization in Nineteenth-Century China" in The City in Late Imperial China, edited by G. W. Skinner, Stanford University Press, 1977.)  Here are three maps developed by Skinner and his collaborators on the basis of the macroregions analysis.

This is a particularly expressive map of the Lower Yangzi macroregion, differentiated into 4 levels of core and periphery.  This is pretty much the full development of the macroregional analysis.

Another key idea in Skinner's work is his analysis of city systems into a spatial and functional hierarchy. He argued that it is possible to distinguish clearly between higher-level and lower-level urban places, and that there is an orderly arrangement of economic functions and marketing scope associated with the various urban places in a macroregion.

So regional analysis of China is a key contribution in Skinner's work. But Skinner did not restrict his research to China alone. He also did significant work on Japanese demography and family structure and female infanticide in the 1980s (for example, "Reproductive Strategies and the Domestic Cycle among Tokugawa Villagers," an AAS presentation in 1988).

And he brought his regional systems analysis to bear on France in an extended piece of research in the late 1980s. The maps that follow are drawn from an unpublished conference paper titled "Regional Systems and the Modernization of Agrarian Societies: France, Japan, China," dated 1991. This paper builds upon a 1988 paper titled "The Population Geography of Agrarian Societies: Regional Systems in Eurasia."

This analysis builds a view of France as a set of interrelated regions with core-periphery stucture.  Through the series of working maps Skinner painstakingly constructs an empirically based analysis of the economic regions of France in mid-nineteenth century.  And Skinner then asks one of his typically foundational questions: how do these geographical features play a causal role in cultural and demographic characteristics?

This map of never-married/married female ratios is one illustration of Skinner's effort to relate social, cultural, and demographic variables to the core-periphery structure of a region.  The pattern of high ratio corresponds fairly well across the map of France to the regions identified by demographic and agricultural factors.  And this serves to confirm the underlying idea -- that economic regionalization has major consequences for cultural and demographic behavior.

Likewise patterns of female life expectancy and net migration; here again we find the kind of regionalization of important social variables that Skinner documents in great detail in late imperial China.

Finally, Skinner also played an important role as a “macro-historian” of China.  His 1985 Presidential Address to the Association for Asian Studies was a tour-de-force, bringing his macroregional analysis into a temporal framework (Skinner, G. William. 1985. Presidential Address: The Structure of Chinese History. Journal of Asian Studies XLIV (2):271-92).  In this piece he demonstrates a “long-wave” set of patterns of economic growth and contraction in two widely separated macroregions.  And he argues that we understand China’s economic history better when we see these sub-national patterns.  He analyzes the economic and population history of North China and Southeast Coast, two widely separated macroregions, over several centuries.  And he demonstrates that the two regions display dramatically different economic trajectories over the long duree.  Skinner brings Braudel to China.

Here is the pattern he finds for two macroregions over a centuries-long expanse of time.  And significantly, if these patterns were superimposed into a “national” pattern, it would show pretty much of a flat performance, since the two macroregions are significantly out of phase in their boom and bust cycles.

Finally, an enduring contribution that Skinner made is his cheerful disregard of discipline. Economic anthropology, regional studies, demography, urban studies, history … Skinner moved freely among all these and more. It was topics and questions, not disciplinary strictures, that guided Skinner’s fertile and rigorous imagination.  And area specialists and social scientists alike can fruitfully gain from continued study of his research.  Fortunately, work is underway to make Skinner's unpublished research and data available to other scholars.  Here are some major projects:

• Data and maps are being curated and presented at Harvard. Here is a beta site and here is the platform the China GIS team is using at AfricaMap.
• The Skinner Archive at Harvard (link)
• Skinner's unpublished papers and research materials are being digitized and presented at the University of Washington.  Here is a link.
• The China Historical GPS project at Fudan University is presenting an ambitious digital mapping collection as well (link). 

(Presented at the Association for Asian Studies, Philadelphia, March 2010; panel on Skinner's legacy.)

Recent historiography of China

The field of China history evolved rapidly after the McCarthy attacks on the field in the 1950s. The most significant developments, in my view, are these. First, there developed in the 1960s and 1970s what Paul Cohen refers to as a “China-centered” approach to the study of the history of China (Discovering History in China: American Historical Writing on the Recent Chinese Past; 1984). The central notion here is the idea that historians of China need to analyze China’s history making use of concepts and hypotheses specific to its own experience. Cohen puts the point this way: “The main identifying feature of the new approach is that it begins with Chinese problems set in a Chinese context. . . . [These] are Chinese problems, in the double sense that they are experienced in China by Chinese and that the measure of their historical importance is a Chinese, rather than a Western, measure” (Cohen 1984, p. 154). Rather than asking whether China experienced “sprouts of capitalism” in the Ming Dynasty, we need to consider the distinctive features of China’s economic development. Rather than considering whether China was a “feudal” society, we need to identify and conceptualize the specific features of political and economic relations that linked elites and the common people.

The point here is not that China’s history is unique and sui generis, but rather that one should not presume that the categories of politics, social structure, and historical process that emerged as central in the unfolding of early modern Europe will find natural application in the historical experience of China. The concept of feudalism is not a trans-historical category which should be expected to have application in every process of historical development. Bin Wong pushes this view further in his China Transformed: Historical Change and the Limits of European Experience.

Second, there has emerged a substantial emphasis on material culture in the China field: social and economic circumstances, the technology of agriculture, marketing hierarchies, and the circumstances of life of ordinary Chinese people. Features of local material culture find prominent expression: population processes, local politics, agricultural technique, land tenure arrangements, patron-client relations, banditry, and environmental change. And since historical China is an agrarian society, this means that agrarian histories have been particularly important in the China field. (Here is a post on China's agricultural history; link.)

Third, China studies have moved in the direction of local or regional studies rather than national histories. Issues arising out of consideration of the village rather than the capital city have come to the fore: the village, the marketing hierarchy, and the region have come to define the focus of inquiry. Scholars are suspicious of generalizations about China as a whole; rather, local and regional variations are the focus of research. It is recognized that lineage is more significant in the south of China than the north; that rice cultivation imposes a series of social imperatives in the south that are absent in the north; that regions linked by water transport show an economic and social integration often lacking in administratively defined units (provinces); that millenarian Buddhism is a powerful factor in the political culture of Shandong but not in Sichuan; and the like. Huaiyin Li's Village China Under Socialism and Reform: A Micro-History, 1948-2008 is a good example of this kind of detailed local study.

Finally, the influence of the social sciences in the field of Chinese history has been of great importance. Much (though of course not all) of the most productive historical research on China in the past two decades has made substantial use of the tools of social science to construct explanations of Chinese historical processes. Techniques drawn from historical demography, economic geography, and the study of organizational behavior have substantially increased our understanding of China’s history. Work by James Lee and numerous collaborators on China's demographic history provide good examples of the fruitfulness of this approach; Life under Pressure: Mortality and Living Standards in Europe and Asia, 1700-1900 (Eurasian Population and Family History).

Here are a few topic areas that have proven to be particularly important.

Spatial organization of culture and economy. China studies have been strongly influenced by the insight that there is a critical spatial dimension to processes of social, political, and economic change. In his groundbreaking work on marketing hierarchies and the regionalization of traditional China, G. William Skinner has demonstrated the key role that transport systems, central place hierarchies, and physiography play in China’s history (link, link.) Skinner’s work has been remarkably influential in the China field; among his contributions, two are especially important. First, Skinner undercut the village-oriented perspective of much existing research on peasant China by putting forward an analysis of the central place hierarchy that exists among cities, market towns, villages, and hamlets in traditional China (Skinner, G. William. 1964-65. "Marketing and Social Structure in Rural China." Journal of Asian Studies 24(1-3)). These hierarchies are knit together by transport systems and the circulation of products, traders, craftsmen, martial arts instructors, necromancers, and other itinerant folk. This is an important contribution because it suggests stimulating hypotheses about the mechanisms of popular culture, the transmission of ideas, the movements of peoples, the diffusion of new technologies, and other fundamental aspects of social change. The second signal contribution contained in Skinner’s work is his regionalization of China into nine “macroregions,” each of which is analyzed in terms of a core-periphery structure (The City in Late Imperial China; 1977). This construct incorporates the structure of marketing hierarchies into the analysis and adds the notion that the economic processes implicit in urbanization impose a structure on rural society as well. Urban cores create a demand for resources (firewood, food, raw materials) that extend economic influence into peripheral areas.

These ideas have a number of important implications for agrarian studies more generally. First, the spatial organization of settlements--villages, towns, and cities, and the transport and marketing networks that connect them--has important consequences for diverse aspects of rural life. Ideas, political movements, and knowledge are diffused through marketing system channels. Itinerant merchants, artisans, letter writers, necromancers, fortune-tellers, or martial-arts instructors travel the circuits defined by the marketing hierarchies; and through these travelers results movement of ideas, products, rumors, skills, and innovations.

Environmental history. There are numerous examples of recent works that give central focus to environmental and ecological issues in China’s history. Environmental issues come in a number of forms in Chinese history, including especially water management, land reclamation, and deforestation. As Skinner points out, there is a strongly spatial orientation to each of these sets of issues: water systems constitute one of the lineaments determining patterns of settlement; land reclamation and deforestation follow population density (and therefore tend to correspond to a core-periphery structure, with a transfer of fertility from periphery to core). 

An important treatment of the human impact on the Chinese environment is Peter Perdue’s study, Exhausting the Earth: State and Peasant in Hunan (Perdue 1987). Perdue’s study focuses on Hunan, 1500-1850, and places primary emphasis on the processes of agricultural change, land reclamation, and water control through which the landscape of Hunan was dramatically altered throughout this period. The struggle between the state and local interests over such issues as taxation, land reclamation, dike building, and land property rights is highlighted.  What is most original about the book is Perdue's success in identifying the consequences for ecology and land and water management of the political and economic processes involved in Hunan’s substantial growth during this period. Perdue documents the slow process through which land reclamation efforts and dike-building nibbled away at Dongting Lake (now China’s second largest lake). The state played an important role in stimulating this process in the Ming dynasty; in the Qing, Perdue indicates that the private interests of local elites and landowners were the driving force for continuing encroachment on wetland and lake margins.

More recently Mark Elvin’s The Retreat of the Elephants: An Environmental History of China provides a broad treatment of China’s environmental history over a longer and broader scope (link). 

State-society relations. State-society relations play an important role in many contemporary studies: to what extent, and through what mechanisms, is the state in a pre-modern society able to effect its will on its population? This question is particularly salient in the case of China because of the somewhat paradoxical role that the Imperial state plays in Chinese history. The Imperial system is often portrayed as weak and ineffectual; at the same time, it is the embodiment of a refined and sophisticated administrative apparatus. To what extent was the Chinese state able to carry out its essential functions--the extraction of taxes, the preservation of order, the suppression of social unrest, the maintenance of large-scale water projects, and the administration of central grain policies? These issues impact on agrarian histories in diverse ways: mobilization of peasant unrest is affected by the extractive behavior of the state, on the one hand, and the effectiveness of the state’s coercive apparatus, on the other.

In Rebellion and its Enemies in Late Imperial China: Militarization and Social Structure, 1796-1864 Philip Kuhn emphasizes the limitations of the grasp of the imperial state in his analysis of the local and regional responses to the Taiping Rebellion. “Local militarization posed acute problems for the imperial state; for if irregular military force could not be regularized and brought under control, if the widespread militarization of local communities could not be brought into a predictable relationship to the state, then the security of the state itself might soon be shaken” (Kuhn 1980, p. 9). There was a logic to the process of the state’s diminishing capacity to effect its will in response to rebellion. “The Ch'ing military establishment lent momentum to the downward spiral of dynastic decline: the worse the troops, the longer it took them to quell an uprising; the longer it took them, the greater the cost; the more impoverished the government, the lower the quality of imperial administration and the greater the frequency of revolt” (126). On Kuhn’s interpretation, the local militarization that occurred in response to the Taiping Rebellion had a permanent effect on the balance of power between center and periphery in Chinese politics.

In his study of state-society relations in North China, Culture, Power, and the State: Rural North China, 1900-1942 (1988), Prasenjit Duara emphasizes the “state-making” processes that were underway in the late Qing. Duara’s analysis focuses on the end of the Qing dynasty and the turn of the twentieth century in North China; Duara attempts to comprehend the variety of institutions, elites, and influences through which political power was wielded at the village level. The state was earnest in its efforts to penetrate rural society to the village level, and Duara examines the efforts made to extend the administrative structures of the state into the system of lineage and local power relations which had traditionally dominated village society.

Intermediate between studies of the Imperial state and local agrarian histories is the effort to discern the “patterns of dominance” exercised by Chinese local elites (Esherick and Rankin, eds., Chinese Local Elites and Patterns of Dominance, 1990). Studies by Keith Schoppa, Mary Rankin, Phillip Kuhn, and William Rowe provide instances of in-depth efforts to identify the historical identities of Chinese elites, rural and urban, and some of the mechanisms through which these elites endeavored to influence local society.

The core-periphery analysis mentioned above has been found fruitful as well in analysis of banditry, rebellion, and smuggling. The grasp of the state tends to be weakest in peripheral areas with difficult terrain (mountains, deserts, marshes), sparse settlement, and poor transport networks; and consequently anti-state activities find natural refuge in such areas.

Vivienne Shue's The Reach of the State: Sketches of the Chinese Body Politic is an important contribution to this topic.

Other topics.  Most recently the China field has been interested in the “involution” debate, culminating in Huang (The Peasant Family and Rural Development in the Yangzi Delta, 1350-1988), Pomeranz (The Great Divergence: China, Europe, and the Making of the Modern World Economy.), and Wong and Rosenthal (Before and Beyond Divergence: The Politics of Economic Change in China and Europe) (link, link, link). And, of course, there is a very large historiography of the Chinese Revolution and the Cultural Revolution.  Several earlier posts provide discussion of post-1960s treatments of the Chinese Revolution; link, link.

These topics are certainly not exhaustive.  I've said nothing here about cultural and identity studies; studies of ethnic minorities in China; popular culture; and much else.  But the field is large, and it is worthwhile for the non-specialist to have at least a rough map of some of the large pathways explored in the past forty years as historians have sought to make better sense of China's history.