A World-Systemic Approach

to Social Evolution

Professor Thomas D. Hall

Department of Sociology & Anthropology

DePauw University

Greencastle, IN 46135-0037

internet: thall@depauw.edu

and

Christopher Chase-Dunn

Department of Sociology

Johns Hopkins University

Baltimore, MD 21218

internet: CHRISCD@JHUVM.HCF.JHU.EDU

Paper presented at American Sociological Association meeting,

New York, NY August 16, 1996.

Panel on Long-Term Historical Change

[v. Aug. 12, 1996]

ABSTRACT: We present a puzzle: why, for well over two millennia, have events across northern Eurasia been coordinated, while those in South and Southeast Asia have not? We also explore tentative answers to this puzzle by exploring the connections among various world-system cycles in Eurasia over the last two millennia. Or analysis underscores that one can not account for long-term social change without carefully attending to inter-group interactions. That is, some sort of world-systems-like perspective is a vital tool for understanding how human societies evolved from a collection of hundred thousand or so nomadic foraging bands to the single complex and global system we have today. While the study of intergroup or world-system interactions are necessary, they are not sufficient to explain long-term social change.

Introduction

In this paper we present a puzzle we uncovered in the course of extending world-system analysis into precapitalist settings. We also explore tentative answers to this puzzle. The puzzle in short is the connections among various world-system cycles and the linkages of social changes in most, but not all of Afroeurasia over the last two, and maybe even three, millennia (see Figure 10, below).

We use this puzzle to underscore our strongest claim that one can not account for long-term social change without carefully attending to inter-group interactions (Chase-Dunn and Hall 1997, 1996a, 1996b, 1995a, 1994, 1993). In other words some sort of world-systems-like perspective is a vital tool for understanding how human societies evolved from a collection of hundred thousand or so nomadic foraging bands to the complex and global system we have today. We underscore that our claim that intergroup or world-system interactions are necessary, but not sufficient for explaining long-term social change.

We also find that systems of inter-group interactions, what we call world-systems or core/periphery relations, are characterized by several different types of cycles: (1) pulsations in the spatial extent of interaction networks; (2) sequences of rise and fall of large polities; and (3) oscillations between state-based and private forms of accumulation. While the evidence on all three of these cycles remains somewhat problematic, we are convinced there are regular social processes in need of explanation.

In this paper we sketch some explanations for these cycles, especially the first two. In this seek to do the following: (1) suggest plausible accounts for these cyclical phenomena; (2) articulate those explanations with our theory of world-system evolution; (3) use our explanation to further refine concepts; and (4) suggest ways in which these cyclical phenomena might be studied empirically and theoretically.

We begin by sketching our concepts of precapitalist world-systems analysis. Then we discuss three processes of world-system expansion: incorporation of new areas or peoples, mergers of formerly autonomous world-systems, and semiperipheral development. We then summarize our theory of world-system evolution. Since we have presented these ideas elsewhere in detail, we present them here only with sufficient detail to set up the discussion of our puzzle.

After a brief discussion of why all world-systems pulse, why states rise and fall, and why accumulation oscillates from state based to private means, we delve into the puzzle: why events at the two ends of Eurasian landmass have been correlated for at least two millennia, but events in South Asia are not. We illustrate with an historical explanation that focuses on the development of Southeast Asian states, and conclude with a brief summary of what we have learned.

Concepts for Analyzing Precapitalist World-Systems

Because our goal in studying precapitalist world-systems continues to be the study of transformations, we maximize number of potential cases by including all sedentary human groups for the last ten thousand years or so. To facilitate broad comparisons we define world-systems as intersocietal networks in which the interactions (e.g., trade, warfare, intermarriage, information) are important for the reproduction of the internal structures of the composite units and importantly affect changes that occur in these local structures. This definition allows the possibility of intersocietal networks that are not world-systems, leaves open the issue of inequality, allows for empirical discovery of types of world-systems, and allows empirical investigation of the existence, nature, and number of transformations.

Because of the vital importance of the ability to produce more than is needed for immediate consumption, we argue that the fundamental characteristic of every world-system is its "mode of accumulation." By mode of accumulation we mean the deep structural logic of production, distribution, exchange, and accumulation, which constitutes a logic of development. While our position is avowedly materialist, we do leave open possibility that non-material factors may sometimes initiate social change, although the logic of any mode of accumulation severely limits such possibilities.

A working, heuristic, typology of modes of accumulation includes: (1) kin-based modes of accumulation; (2) tributary modes; (3) capitalist modes; and possible (4) socialist modes. The same system may include more than mode. Thus, we speak of a "predominant" mode, which dominates and organizes the others, but does not necessarily permeate the entire world-system. For instance, feudalism is a sub-type of the tributary mode, one of its most decentralized forms. Conversely, the so-called "Asiatic" form, in which the state owns the land, is one of the most centralized forms of the tributary mode.

While such transitional and mixed forms complicate the analysis of transformations, we contend that there have been qualitatively distinct logics of accumulation. We reject all theories of unilinear evolution. Rather, we see historical social change as an open-ended and path dependent. That is, change occurs in any existing social structure within the context of its historical legacy and its current conditions. We see discontinuities of development, rapid transformations, and instances of devolution as normal characteristics of social change (see Sanderson 1990, 1995a). Hence, we expect the presence of many messy intervening types.

The key concepts of core and periphery which remain controversial even for the study of the modern world-system (Arrighi and Drangel 1986; Chase-Dunn 1989: Ch. 10), are even more problematic in precapitalist settings. To facilitate the study of the emergence of inequality we distinguish between core/periphery differentiation, in which societies at different levels of complexity and population density are in interaction with each other within the same world-system and call core/periphery hierarchy, in which political, economic, or ideological domination exists among different societies within the same world-system. Following Myrdal (1971) we also distinguish between spread effects, in which core-periphery interactions cause peripheral areas to become more core-like and backwash effects, in which core-periphery interactions cause peripheral areas to become less core-like (or the development of underdevelopment [Frank 1966]). The relative densities and roles of spread and backwash effects in world-system evolution, especially the emergence of hierarchy from core/periphery differentiation remain important empirical and theoretical issues.

Core/periphery relations can be even more complex. Mitchell Allen (1996: Chapter 1) has developed the concept of a "contested periphery," a peripheral region for which one or more core regions compete. Based on elaborate case-study of Philistia and its relations to the Neo-Assyrian and Egyptian world-systems he finds that once an area has been incorporated into one world-system it can more easily be moved into another world-system than if it were being incorporated for the first time. This prompts us to argue that the concept of semiperiphery should include:

1.	A semiperipheral region may be one that mixes both core and peripheral forms of organization.

2.	A semiperipheral region may be spatially located between core and peripheral regions.

3.	A semiperipheral region may be spatially located between two or more competing core regions.

4.	Mediating activities between core and peripheral areas may be carried out in semiperipheral regions.

5.	A semiperipheral area may be one in which institutional features are in some ways intermediate between those forms found in core and peripheral regions.

Any narrowing of the concept of semiperiphery should be based on empirical research.

Finally, we argue that world-systems are the primary unit of analysis for understanding these processes, but not the only unit. World-system analysis--in modern or precapitalist settings--must always attend to the complex dialectic between social change within any of its composite units and social change of the entire system. In order to this it is important to be able to bound world-systems in ways that do not include "systemness" in the definitions of boundary criteria.

Spatial Boundaries:

A Multicriteria Approach

Because our focus is on connections, we study interaction networks rather than the distribution of various traits. While we argue that the types of interactions to study should be determined empirically, we must begin with some specifics. We note that the spatial range of consequences of all kinds of action increase as transport and communications costs decrease. Thus, interaction tends to abate with distance, what Colin Renfrew calls "fall-off" (1975, 1977). Thus, we propose that the boundaries of a system should be delineated by tracing the densities of exchange. A sharp decline in density of interaction constitutes a boundary. Because of the fall-off problem and use of relative densities rather than absolute cessation of interaction, many boundaries are fuzzy empirically. This "fuzziness," however, is a real property, not an artifact of poor measurement (see Chase-Dunn and Hall 1997: Ch. 7 for detailed examples).

Clearly, economic forms of interaction are important features of all world-system networks. Of these, bulk-goods exchanges are important, constitutive forms of interconnection (Wallerstein 1974a, 1974b, 1979a). However, we also agree with Jane Schneider (1977) that luxury goods, especially when they are used in a prestige-goods economy (Peregrine 1996), are very important for the reproduction of power structures. We expect that the prestige goods net may be several orders of magnitude larger than the other nets.

Intermarriage networks can also be used to bound systems, especially in kin-based systems where they are a fundamental bases of geopolitics and geoeconomics (Collins 1992). Furthermore, marriage exchanges in kin-based systems almost always are associated with exchanges of bulk and prestige goods.

For political interconnections we use regularized political-military conflict interaction (Wilkinson 1987a, 1987b; Tilly 1984:62). Typically, this network will differ from the bulk-goods or prestige-goods networks. Finally, we note that networks of information in many forms including, but not limited to, ideology, religion, technical information, and culture also serve as bounding mechanisms. We do not expect such information networks to coincide with any of the other networks.

Thus, we propose four sets of bounding criteria: (1) a bulk goods exchange network (BGN); (2) a prestige goods exchange network (PGN); (3) a political/military exchange network (PMN); and (4) an information exchange network (IN). Often these networks will be nested boundaries, with the bulk goods net the smallest and the prestige goods net the largest. The information net will of the same order of size as the prestige goods net: sometimes larger, sometimes smaller. Figure 1 presents an abstract model of these four nets. It is suggestive, not definitive. Rather than a priori privileging one of these networks, we propose that world-systems may be constituted by any or all these linkages.

(Figure 1 about here)

We do not claim that the networks will always be nested in the fashion described. Occasionally, as in both the modern global world-system and some earlier geographically isolated systems (e.g., the Hawaiian Islands), these four networks converge. The relative placements of the four nets may be an important characteristic which differentiates world-systems.

We do, however, expect that the relative sizes of the nested networks may change through time. Figure 2 shows one possible sequence. Reading Figure 2 from left to right as an historical sequence, we note that the bulk goods and political/military nets increase in size relative to the prestige goods and information nets. Second, the information net shifts through time. These shifts suggest significant changes in intersocietal relations and in the conditions and costs of travel and transportation. Again, the figure is suggestive of the types of changes we might find.

(Figure 2 about here)

We can also imagine three contemporaneous, separate world-systems, all of which expand (see Figure 3a). If they all, or even only one, expands sufficiently, one or more of the boundaries between them will merge. Thus, the information and prestige goods nets might merge while the political/military and bulk goods nets remain separate (Figure 3b). Finally, conquest might merge two of the political/military nets (Figure 3c).

(Figures 3a, b, c about here)

Before turning to our account of world-system transformations, we will review some of the processes through which world-systems change.

Incorporation, Merger, and Semiperipheral Development

World-systems tend to grow. Societies have gotten larger, in terms of population, population density, territorial extent, absolute and relative productivity. Growth necessarily entails absorption of formerly external areas, the incorporation of new peoples and territories and/or the merger of formerly autonomous world-systems. Throughout these processes no core area remains a core area indefinitely. They are replaced, often by a formerly semiperipheral region. All three processes, incorporation, merger, and semiperipheral development play important roles in world-system evolution and dynamics.

INCORPORATION

Incorporation involves the absorption of territory and typically its residents into a larger world-system. Mergers occur when systems with comparable levels of complexity unite. Incorporation and merger might best be thought of as poles of a continuum, rather than opposites. We discuss the polar extremes, knowing that intermediate are probably common.

Incorporations or mergers can occur at each network level. Two separate systems are first likely to interact through the information network. If one or both are expanding they will later become part of a single prestige goods network, and still later they will join into a single political-military network, and then a single bulk goods network (see figures 3a, b, c). This sequence is likely to be the same regardless of the relative levels of complexity of the two systems. However, their relative levels of complexity will often be an important element in the nature of their interactions.

We conceptualize incorporation as a continuum that ranges from weak to strong (see Hall 1986, 1989, 1996; Chase-Dunn and Hall 1997:Ch. 4). At the weak pole are areas external to a world-system; next are areas where contact has been slight. We call these external arenas and contact peripheries respectively. In the middle range are marginal peripheries," or "regions of refuge." At the strong pole are "full-blown," or dependent peripheries (see Figure 4).

(Figure 4 about here)

Key points of this conceptualization (see Hall 1986, 1989) are: (1) that even at very a weak level, incorporation can have dramatic effects; (2) that while somewhat reversible, incorporation is "sticky" or "grainy," tending in general toward stronger levels and very seldom returns to the status quo ante (contra Arrighi 1979); (3) that even at very weak levels of incorporation, peoples in these newly peripherialized areas attempt to control and shape the process, often with a modicum of success; and (4) that conventional world-system analysis has examined only strong levels of incorporation where backwash effects have been very strong, and thus have mis-specified the overall process.

Similarly, plunder--whether it was Nuer raiding the Dinka for cattle and wives (Kelly 1985) or Spaniards looting Inka treasures--is a form of incorporation within the PMN. Thus, West Africa was incorporated into the PMN of the Central system when slave raiding became regularized, rather than, as Wallerstein (1989: Ch. 3) would have it, after the development of colonial agriculture in Africa. We accept, however, that the conventional focus on strong incorporation is based on the recognition that economic exploitation is a more stable than plunder because it does not destroy the peripheral economy and it is often sustainable.

Thus, incorporation creates frontier zones where many "mixed" and hybrid social forms abound. Our main points are: (1) that "frontiers" are formed and transformed by world-systemic processes, and cannot be fully understood by examining only the frontier itself (see Hall in press a, b); and (2) that even the earliest ethnographic accounts of so-called "pristine" forms of societies are actually accounts of groups that have been dramatically transformed by contact with and absorption into expanding world-systems.

Eric Wolf (1982) and Brian Ferguson and Neil Whitehead (1992) present many examples or processes which point to the dramatic consequences and the limited reversibility of the effects of incorporation of nonstate peoples into state systems: precapitalist, mercantile, or capitalist. Because these effects often spread far beyond the zone of contact, many so-called "pristine" ethnographic examples are actually the products of earlier, radical transformations.

The incorporation process varies with both the type of world-system doing the incorporating and the type of group being incorporated. One very important difference is between state and nonstate groups, or between what we call kin-ordered systems and tributary or capitalist systems. The organizing principles of each are fundamentally different. Members of each have difficulty in understanding how the other works. Colonial histories are full of examples of leaders in one of these types describing the other as without "order" or without "reason." This is why state-based world-systems almost always attempt to impose some degree of political centralization on nonstate peoples.

Why an area was incorporated shapes the consequences of a severance or weakening of core domination. If the core is extracting some local resource, such as human captives for slaves, the loosening or severing of that connection would typically allow a return of local prosperity. If, on the other hand, the core supplied some resource for which there was no local substitute, such as guns, any prosperity that was a consequence of access to that resource would typically collapse with its loss.

MERGERS

Mergers seem to be somewhat different. First, incorporation or merger of a state-based world-system is costly process because states are capable of powerful resistance to incorporation or merger. Second, following the "no intervening heartland" rule (Collins 1978, 1981, 1986b), expansion that entails passing through the heartland of another state is likely to fail. This is why most successful expansion typically is into contiguous territories. Third, tributary empires more often engage in plunder, whereas the capitalist system seems to favor capitalist production, even of raw materials. Fourth, the merger of world-systems seldom results in the peripheralization of one by the other. Rather, it constitutes a new, larger world-system in which the two formerly separate systems play more or less equal parts, creating a multi-cored world-system. The two most well-known instances are the merger of the Mesopotamian and Egyptian systems and the merger of Afroeurasia. Obviously, throughout human history many small systems must have merged to make larger ones.

Another mechanism world-system change is semiperipheral development.

SEMIPERIPHERAL DEVELOPMENT

We argue (1997: Ch. 5; see Chase-Dunn 1988, 1990) that the semiperiphery is a fertile ground for social, organizational, and technical innovation and is often the locus of new centers of power. In particular, secondary state-formation on the marches of empires has frequently been recognized as a phenomenon that is related to the rise and fall of empires and the shift of hegemony within interstate systems (e.g., Mann 1986). A broadly similar phenomenon occurs among chiefdoms( e.g. Kirch 1984:204). Semiperipheral capitalist city states in the tributary world-systems and some semiperipheral national states in the modern world-system have been upwardly mobile and played transformative roles.

The question is, why are the processes that facilitate new and adaptive organizational forms more often found in marcher states than in older core regions?

Randall Collins (1978, 1981) contends that the advantages of states in the marchlands is primarily geomilitary. Because they are near the edge of the core "heartland" they do not need to defend several borders at once and so they can concentrate their resources on a strategy of conquest that adds territory sequentially without threats from the rear. The disadvantage of older core powers is that they must defend themselves from many sides and so their resources are spread thinly.

Problematic as the evidence is, studies of the rise of Sargon of Akkad, the first unifier of the Mesopotamian city states (Chase-Dunn 1988; Chase-Dunn and Hall 1997: Ch. 5), suggests that Sargon's success also hinged on considerable knowledge of state administration in combination with the freedom of Akkad from the demands for organization and control typical for core powers. Thus, Sargon combined elements of a peripheral kin-based mode of production with those of the core tributary mode to conquer the Sumerian core. He then established a more centralized, more exploitative, purer form of the tributary mode of production than had ever existed before.

This ability to combine old with new more productive ways occurred very often in capitalist city-states which typically existed in the semiperipheral interstices of empires dominated by the tributary mode of accumulation. The city-states of antiquity were semiperipheral because they were on the edges of, or the boundaries between, large territorial empires. Spatially they could easily mediate trade between the core empires and peripheral regions. They could sometime manipulate this position to maintain considerable degree of political and economic autonomy, although they were not infrequently swallowed up by imperial expansion (Frankenstein 1979). Some were formally sovereign: Dilmun, Byblos, Tyre, Sidon, Carthage, Malacca, Venice, Florence, Genoa, Antwerp, and the cities of the Hanseatic League.

Many of these cities were involved in maritime trade. Coastal location made them easier to defend from potential conquerors leading land-based armies. Also, as is well known, easy access to water transport lowers transportation costs, and thus the ratio at which goods become luxuries rather than bulk items. These cities often engaged in manufacturing of goods that facilitated their trade-based strategy of accumulation. They were powerful agents of commodification and commercialization in the still predominantly tributary world-systems. Indeed, we argue at length elsewhere (1997, Chs. 5, 9, 10), the "rise of the West" is best understood as an instance of semiperipheral development -- an upwardly mobile semiperipheral region within the larger Afroeurasian system that eventually succeeded in dominating the entire globe.

We are now prepared to present a brief version of our theory of world-system transformations.

World-System Evolution

If our hypothesized typology of modes of accumulation is correct, we have only two transformations to study: the transition from kin-based to state-based or tributary logics and the transition from tributary to capitalist logic. A transition to whatever follows capitalism would constitute a third transformation. We argue that the study of transformations should include:

1. Treating hierarchy as an empirical issue;

2. Conceptualizing commodification as a variable process;

3. World-system interaction networks should be studied empirically;

4. While patterns and general principles may emerge from comparative analysis, they must be grounded in historical details.

Our explanation of world-system evolution is built on a basic iteration model that involves feedback loops among population pressure, social organization, including especially the ways in which people make their livings (mode of production), environmental degradation, intergroup conflict, and degree of boundedness or circumscription (Carneiro 1970). The basic components are all familiar models, assembled in our iteration model (see Figure 5).

(Figure 5 about here)

While many writers (e.g. Harris 1977, 1979, Johnson and Earle 1987) have used one or another variation of these processes to explain the neolithic revolution and origin of states, the growth of state-systems into empires and the origin of capitalism have been less satisfactorily accounted for by such explanations. Sanderson (1995a) summarizes these explanations and argues that other types of explanation are needed for these changes, ones that include increasing commercialization and some world-systemic processes.

We note that increasing trade and commercialization propagated pathogens along trade routes which connected informational and prestige goods networks. William McNeill (1976) traces how these pathogens unleashed the Black Death in Europe and similar outbreaks in China. Such "virgin soil epidemics" (Crosby 1972, 1986) have occurred many times in human history, typically when formerly isolated groups first came into contact. As is well know they can be extremely disruptive (see, for example, Reff 1991; Thornton 1987).

Semiperipheral states often play a special role in system transformation because they typically have the "advantages of backwardness" (Gerschenkron 1966). They have access to latest technologies, including what Michael Mann (1986) calls "techniques of power," but have not yet become burdened with the costs of empire, or in Tainter's (1988) terms, have not reached a point of declining marginal returns. When a semiperipheral state is located on the edge of a system so that it is not vulnerable to attack from two directions it can eliminate core competitors one at a time and come to dominate the system.

Our explanation is that the cyclical (pulsation) expansion of world-systems changes the dynamics of the basic iteration process. Expansion temporarily enhances the direct effects of population density on hierarchy formation and technological intensification through bypassing the usual indirect effects via environmental degradation and increased intergroup conflict (see Figure 6). Instead of always leading to environmental degradation and increasing conflict, expansion can serve as an outlet for population growth via the acquisition of new territories, resources, and even more population. This, in turn, triggers attempts to find new ways to administer considerably expanded state activities. Two kinds of solutions are particularly useful: increasing hierarchy--both throughout the system, and within its component states--and changing mode of production. If, and only if, a solution to the problems of administration is found, will the effect of population pressure again become indirect through environmental degradation and intergroup conflict. If a solution is not found--the more typical case--then the system will expand and collapse, following a pattern much like the pattern of decreasing marginal returns described by Tainter (1988).

(Figure 6 about here)

While still sketchy, this explanation solves a difficult problem: the combination of occasional large changes embedded in an interrupted stream of continuous change (see Diagram 7). These interruptions are generated by the cyclic process of world-systems, not contradictions inherent in states or societies--although such contradictions are part of those cycles. Thus, world-systems are the key unit of analysis of understanding social evolution. However, the case should not be overstated. This does not mean that state- or society-based processes are irrelevant--clearly they are relevant. Rather, it means that they must be embedded or contextualized in larger, world-systemic processes to be fully understood.

(Figure 7 about here)

We now turn to some of our more interesting findings.

World-System History and Dynamics

The accompanying spatio-temporal chronographs show how the social structures of the human population have shifted through time. The sequence runs from small networks of nomadic foraging bands, to larger systems of mesolithic sedentary foragers, to even larger systems of sedentary horticulturalists, to still larger systems in which core regions included the first cities and early states, to yet larger systems of agrarian empires, and eventually to today's one global capitalist political economy. Figure 8 shows, using PMNs as the unit of analysis, how a "Central" PMN composed of the merging of the Mesopotamian and Egyptian PMNs in about 1500 BCE eventually incorporated all the other PMNs into itself. Figure 8 shows only those PMNs with settlement populations greater than 10,000. Many cityless PMNs were also incorporated.

(Figure 8 about here)

Figure 8 does not show what happened to the other interaction nets. If we were to consider the expanding boundaries of PGNs, the result would look much the same except that the time scale on the left margin would be shifted down (e.g. see Figure 6). For example, the Mesopotamian and Egyptian PGNs became linked probably as early as 3000 BCE, while the PMNs did not merge until 1500 BCE.

WORLD-SYSTEM CYCLES: RISE AND FALL AND PULSATIONS

We have found that all systems we have studied, including even very small and egalitarian ones, exhibit cyclical expansions and contractions in the spatial extent of interaction networks. Based on this, we posit that all four networks--BGNs, PMNs, PGNs, and INs--pulse. By "pulse" we mean that the spatial scale of interaction increases and then decreases at each of these network levels. When interaction increases, there are more exchanges and each exchange has consequences over a greater distance. Thus, interaction densities increase.

We call cycles of centralization/decentralization of political/military power among a set of polities "rise and fall." Again, we observe that for all hierarchical world-systems (whether they are composed of chiefdoms, states, empires, or capitalist states) the larger polities experience cycles of growth, then decline in size and power. However, very egalitarian and small scale systems such as the sedentary foragers of Northern California (Chase-Dunn and Hall 1997: Ch. 7; Chase-Dunn, forthcoming) do not display this kind of cycle. According to Ekholm and Friedman (1982), Frank (1993), and Frank and Gills (1993) all world-systems for the last 5,000 years also oscillate between private and state-based forms of capital accumulation.

That these cyclical processes, pulsation, rise-and-fall, and oscillation, occur in very different kinds of systems raises several questions. Are the underlying mechanisms that generate these sequences the same or similar in all systems? What are the temporal and causal relations among these different cycles? What is the relationship between the rise and fall of large polities and changes in the degree of inequality within polities? Are these relationships similar across different kinds of world-systems? What is the relationship between the rise and fall of large polities and oscillations between state-based and private forms of accumulation? How are political rise-and-fall and network pulsations related to the general 200 year phases of expansion and contraction posited by Gills and Frank (1992; Frank 1993)? Are these cycles really synchronous in regions connected only by very long distance trade in prestige goods? By no means can we answer all of these questions. However, we can illuminate them a little.

QUALITATIVE DIFFERENCES IN RISE AND FALL

First we note that closer examination reveals that some of the cyclical processes have different characteristics and different causes in distinct types of world-systems. Even though the rise and fall of chiefdoms is analytically similar to the rise and fall of empires and of hegemonic core powers and even though all are related to the stability of institutions for extracting resources from distant regions, there are tremendous differences in scale.

There are other important differences. David G. Anderson's (1994) robustly summarizes the anthropological and sociological literature on "cycling" in his study of the rise and fall of Mississippian chiefdoms in the Savannah River valley. These "cyclings" are processes by which a chiefly polity extended control over adjacent chiefdoms and developed a two-tiered hierarchy of administration above local communities. Later these regionally-centralized chiefly polities disintegrated back toward a system of smaller and less hierarchical polities.

Chiefs typically relied more completely on hierarchical kinship relations, control of ritual hierarchies, and control of prestige goods imports than have the rulers of states. States have specialized organizations for extracting resources that chiefdoms lack. In turn, states and empires have been more dependent on the projection of armed force over great distances than modern hegemonic core states have been. The development of commodity production and mechanisms of financial control, as well as further development of bureaucratic "techniques of power" (Mann 1986) have allowed modern hegemons to extract resources from far-away places with much less overhead cost.

The development of techniques of power have made core/periphery relations ever more important in competition among core powers and have altered the ways in which the rise-and-fall process works in other respects. One of these is the degree of centralization achieved within the core areas of the modern capitalist world-system compared to tributary world-systems. Tributary systems alternate between a structure of multiple, competing core states and core-wide (or nearly core-wide) empires. The modern interstate system experiences the rise and fall of hegemons, but the hegemonic core state never even attempt to conquer the other core states to form a core-wide empire. This is because modern hegemons are pursuing a capitalist, rather than a territorialist, form of accumulation. Thus, even omitting nonstate, chiefdom world-systems, there is a significant difference between capitalist and tributary systems.

The simplest hypothesis regarding the temporal relationships between rise and fall and pulsation is that they occur in tandem. Whether or not this is so, and how it might differ in distinct types of world-systems, are questions amenable to empirical research. The spatial relationship between PMNs and PGNs expanded and contracted synchronically across Eurasia over the past 2000 years or more (Chase-Dunn and Hall 1997: Ch. 10; see Figure 9).

(Figure 9 about here)

Figure 9 is a hypothetical depiction of the temporal relationship between PMN and PGN pulsation in the Central and East Asian systems as they expanded, intermittently touched each other, and eventually merged to form the global system. This is the old issue about whether the flag follows trade or trade follows the flag (Webb 1975). In our version prestige goods trade leads the flag, but both expand more or less concurrently. While this portrayal is hypothetical, it would be possible to use actual temporal changes in the spatial extent of PMNs and PGNs to examine empirically the synchronicity of expansion and contraction.

What about the relationship between rise-and-fall and PMN expansion and contraction? It would seem that this also would be temporally synchronized. When core regions are more centralized (during "rise") they contain larger polities with presumably greater spatial reach. This would extend the boundaries of the PMN.

Based on a tenuous assumption that cities grow in periods of expansion, we examined the relationships between changes in the population size of the largest city and changes in territorial size of the largest empire within several different PMNs (Chase-Dunn and Hall 1995:130-131; 1997: Chaps. 9, 10). We found very weak support for simultaneous trade and political/military pulsations.

SYNCHRONIZATION OF PMNs WITHIN THE SAME PGN

While examining the relationships within PMNs of urban and empire growth/decline we discovered that city growth and empire growth seem to occur synchronously in the Central (West Asian and Mediterranean) and the East Asian PMNs (Chase-Dunn and Willard 1993; Chase-Dunn and Hall 1995b). We also found that the intermediate Indic PMN did not experience a similar sequence of growth and decline phases (Chase-Dunn and Hall 1997: Fig. 10.11, see Figure 10). This, then, is our puzzle: why the synchronization across northern Eurasia, but not South Asia?

(Figure 10 about here)

What are the causes of this synchronization? Does this kind of relationship hold in other PGNs? Studies of Mesopotamian and Egyptian PMNs shows that changes in the sizes of the largest cities in these two regions do not seem to be synchronous, nor do all PMNs within larger PGNs have synchronous processes of growth.

Thus, the synchronicity of the growth of cities and empires in the Central and East Asian PMNs remains a puzzle. One possibility is northern Eurasian wide climatic fluctuations. India, at a more equatorial latitude across the Himalayas, may have experienced very different climatic fluctuations. However, does climate change cause urban change, or does the expansion of agriculture associated with urban growth cause climate change? It is possible that expanded agricultural activity, and/or deforestation due to human exploitation, may have affected local and regional rainfall patterns and ground water levels.

Microparasites could also be an underlying cause, mediated through trade networks. As trade increases in density and volume, formerly isolated disease pools come into contact, initiating virgin soil epidemics (Crosby 1972, 1986). Such epidemics can unleash tremendous social, economic, and political changes (Goldstone 1991). As pathogens and hosts adapt to each other, these diseases become less lethal, and populations recover. Trade then resumes, and the cycle can repeat as other, formerly isolated disease pools come into contact, or as new diseases spread along trade networks. This might account for some regularity in such cycles since humans have been able to intervene in the biological processes of mutual adaptation only in the late twentieth century.

If the timing and magnitude of the pulsations are significantly different in chiefdom, tributary, and capitalist world-systems, then we would expect that the explanation is to found in the mode of accumulation, not climatic changes. While the evidence is far from clear, mode of accumulation processes is the more likely source of pulsations.

A third, more interesting, explanation from the world-systems perspective can be drawn from Frank's (1992) argument about the "centrality of Central Asia" as a peripheral region linking both ends of the Eurasian continent and his argument (n.d.) about the centrality of China in the Afroeurasian world-system. Thomas Barfield (1989) built on Owen Lattimore's (1940) observations to trace the long-term linkage of the rise and fall of steppe empires with the rise and fall of agrarian empires in China. Citing this and other evidence Frank (1992) contends that processes of peripheral migration and steppe-empire formation and their affects on the long distance trade carried along the Silk Roads of Central Asia are the explanation of the linkages between Rome and China first reported by Teggart (1939). While there had been early periods of linkage, the Mongol Empire briefly linked the Western Asia and China into a single polity in the thirteenth century CE.

Since warfare affects both urban growth and the territorial size of empires, steppe empire formation and the attendant fighting and migration of pastoral nomads may well be the cause of the simultaneous rise and fall of empires at both ends of the Eurasian land mass. If so, warfare between steppe nomads and agrarian states in both Western Asia and East Asia should be correlated.

A fourth explanation builds on the ways in which South Asia was connected into Afroeurasian trading patterns. India had multiple connections into Afroeurasian trading networks. Overland, either via Hindu Kush passes along the Silk Roads (e.g., Rossabi 1990), via Yunnan and Assam, and by sea. Even the latter are quite old, going back at least two millennia (see Chaudhuri 1985, 1991 and Abu-Lughod 1989). Thus, at any given time, South Asian states had multiple routes of access into trade, so disruption of any one route--for whatever reason--could be compensated for by means of alternate routes. Multiple routes would keep up an early and steady exposure to pathogens so disease pool isolation might be less likely.

THE SOUTHEAST ASIAN CONNECTION

Beyond the multiple routes, a fifth explanation may be found in the extensive relations between South Asia and Southeast Asia which opened up even further routes. At those times when conditions through the straits of Malacca and or Sunda where chaotic or occupied by pirates making sea trade very risky, portages across the Malay Peninsula or overland through northern southeast Asia (what today is northern Burma (Myanmar), Thailand, Laos, and Vietnam were possible). Thus, while a large state (e.g., Funan, Khmer Empire, Srivijaya [Java], and later Siam or the city-state Malacca) could block one or more paths, no one of these state could control all the paths from India to China (see Map 1).

(Map 1 about here)

Indian connections to, and trade with, various Southeast Asian states itself buffered India from blockages on other routes. Southeast Asia supplied aromatic woods, spices, and especially gold. When access to northern sources gold were severed by Bactria in Central Asia and the Romans sought to curb the export of gold to the east in the first centuries of the current era, India turned to Southeast Asia to fill the gap. As Coedes notes (1968:19ff), this was not a gold rush of the kind that occurred to nineteenth century California. Still, the region was known as "the land of gold." Furthermore, Southeast Asia was an outlet for surplus elites, especially Brahmans and Ksatriyas who served in various Southeast Asian states. Since the South Asian connection to Southeast Asia was generally maritime, Indian states did not get bogged down in expensive land wars as China did from time to time.

Following arguments advanced by K. Hall (1985), Kulke (1986), Vickery (1986), Wang (1986), and Wolters (1982), local Southeast Asian polities and leaders may have been the initiators, rather than the receivers of this contact. Local coastal leaders sought to use trade to both enhance their wealth and power, and extend further control over their hinterlands (K. Hall 1985). Indeed, much of the early trade may have been carried by Southeast Asian ships and sailors, rather than by South Asians. If so, our world-system interpretation is further strengthened.

The combination of two streams of infiltration into Southeast Asia by the Thai peoples from the northeast and by the Burmo-Tibetans from the northwest along with impacts of China and various Indian states prevented the formation of a single, region-wide power in Southeast Asia. Funan, located approximately where modern Cambodia is, in the early centuries of the current era came closest to such domination. But even Funan could not control all the routes.

Here we note that if anything, Frank's thesis is understated. Central Asians played a role, albeit and indirect one, in Indianization of Southeast Asia early in the current era. Later, the Mongols, especially in the Yuan Dynasty under Kublai Khan, triggered major changes in the political organization of Southeast Asia. To avoid prolonged wars and insure tribute Kublai sought to support small states and block the formation of large ones. Mongol attacks helped finish the Burmese empire centered on Pagan, already in decline (Aung-Thwin 1985).

As part of their strategy the Mongols sometimes used Thais against Burmese in Pagan and the Khmers from the region around Angkor Wat. Or it may be that local Thai leaders encouraged Mongol attacks against their enemies--or both. The record is not clear. What is clear is that the Mongols also supported the formation of local Thai states, which started a marcher state process that eventuated in the rise Siam.

Three local leaders, Ngam Muang, Mangrai (who founded Chiang Mai 1296), and King Rama Khamhaeng formed an alliance late in the thirteenth century.	Rama Khamhaeng is credited with developing the first Siamese state centered on Sukhotai. He accepted without protests China's demand that he acknowledge the traditional vassalage relationship with China. He thereby gained substantial moral support for his expansionist program. He adapted the Mon-Khmer writing system to the Thai language and made Theravada Buddhism the official religion of the state, although not to the exclusion of ancestral and nature spirits. His governmental system was fashioned according to Khmer standards, while his military recruitment and organizational procedures were based on Mongol practices (Cady 1966:62).

This is a near textbook description of marcher state succession. In due time a new capital was founded at Ayudhya in 1350 which lasted until it was sacked by the Burmese in 1767 and replaced by Bangkok. It is important to note, however, that the entire process occurred in the context of waning Indian influence and declining Chinese/Mongol attempts at empire expansion and incorporation.

Finally, China's withdrawal from oceanic trade early in the Ming Dynasty, in part as a reaction to fear of another Mongol invasion, and in part an attempt to curtail growing power of coastal trading cities, left the southern oceans open to Arab, then European traders (Fitzpatrick 1992).

In short, the states in Southeast Asia play an important role in the connections between China and India, and through India to West Asia and the Mediterranean. However, unlike the Central Asia steppe federations which rose and fell with Chinese empires (Barfield 1989, 1991), the states of Southeast Asia seemed to wax and wane counterpuntally to Chinese and Indian empires.

Thus, for the Mongol era at least, an elaborated version of Frank's Central Asian thesis seems to make more sense of the coordination of events in west and east Asia, and the exceptionalism of South Asia than any other explanation. While not ruling out a role of climatic fluctuations and/or spread of pathogens, it suggests that they were not key factors. Clearly, though, more research is needed to delineate what subsidiary roles these factors played in the coordination of world-system cycles in Eurasia.

There is one addition wrinkle in this Southeast Asian discussion. Michael Aung-Thwin (1985) argues persuasively that the oscillation of the Burmese state system (another semiperipheral marcher state) was typical of all Theravada Buddhist states. Briefly, kings gained legitimacy via sanction of the Sangha--the Buddish monkhood--by making their own and legitimating the donations of others to the Sangha. Through time, however, such donations took much land out of the revenue basis of the state, precipitating a fiscal crisis.

If a reigning king could mobilize a reform movement to "purify" the Sangha by removing its excessive worldly wealth (and thereby recapturing its revenue base), he could restore fiscal soundness. However, in order to gain legitimacy for such moves the king would need to demonstrate his dedication to Buddhist principles by making major donations to the Sangha--typically in the form of extensive temple building. This, of course, restarted the cycle.

If a reigning king could not restore state revenues, he might embark on conquests, but more likely would be subject to them due to the weakened position of the state. This usually began with internecine fighting, further weakening the state, and tempting local rivals to try conquest. Eventually the dynasty would fall, the "empire" would break up into rival petty states, and eventually another strong leader would begin to reassemble a larger state.

The Thai state of Sukhothai came to rival the Burmese state. But in the Ayudhaya phase it too, became subject to the same Sangha - state cycle. The problems of logistics and the no intervening heartland rule (Collins 1978) neither rival could fully conquer the other, although both succeeded in sacking the capitals of the others.

In our terms what happened was that administrative structures and the legitimating role of Theravada Buddhism were insufficient to solve the problems of large-scale administration. Thus, neither the Thai-based or Burmese/Mon-based states systems could become regionally hegemonic and use the resources of the combined, larger, tributary state to embark on a climb to core status.

In short, this is a failed effort at semiperipheral development, but one with immense consequences. Furthermore, the state-sangha interaction cycle illustrates one of the mechanisms of both rise and fall and pulsation in tributary world-systems. There are, no doubt, many others.

Conclusions, Questions & Speculations

In such a brief paper we cannot discuss cases in sufficient richness to make our arguments persuasive, only suggestive. We have done so to some extent elsewhere (Chase-Dunn and Hall 1997). We do however, think we have made a strong case for the utility of a world-systems approach to the study of social evolution. The explanation of the various cycles remains far from complete. However, we do claim that the evidence is sufficient to justify further study of these processes.

Another key lesson from this exercise, emphasizing the issues of world-system incorporation and mergers and related work of Wolf (1982) and Ferguson and Whitehead (1992), is the extreme caution with which first hand accounts of so-called "pristine" social types should be taken. Since as far back as when humans first became partially sedentary, about 10,000 years ago, the social environment has been a major factor in all types of social change. Thus, similarity in form of social organization is an unsound proxy for degree of development.

That similar social forms may be created by very different processes, of course, was one of the key insights of both Andre Gunder Frank's "development of underdevelopment" thesis (1966) and world-system theory as first advanced by Immanuel Wallerstein. What we have added is a deeper dimension to this insight. It extends much further back in time than Wallerstein is willing to claim (1990, 1993, 1995a, 1995b, 1995c), and even further than Frank and Gills (1993) argue.

We can also see that incorporation, merger, and semiperipheral development are both the stuff of history as narrative and social change as systematic processes. However, what is clear about these three processes is that our knowledge and understanding of them is very far from clear. We need to re-examine world history with these types of processes in mind, using them not as a procrustean bed onto which we pound all of history, but as working hypotheses to direct our questions and rules of thumb in our pursuit of answers.

Thus, as we explore various specific cases we need to constantly rethink our concepts and theories. And as the Southeast Asia example illustrates, we need to attend closely to the warnings of Hodgson (1993), Blaut (1993) and Frank (n.d.) to avoid Eurocentric theorizing. If we must ground our theorizing in concrete cases--as all theory must be grounded--we would be well advised to ignore Europe and focus on Asia.

In summary, we do not claim that a world-system perspective can supply all the right answers about social change. We do, however, claim that it leads to many useful and interesting questions.

Notes