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Human history has been punctuated with patterns of civilizational growth and decline. Cognizance of societal collapse can be traced to (at least) the ancient Greeks, who developed the notion that civilizations are organisms (which go through cycles of birth, growth, and death). This organismic conception had more recently been expressed in the 20th century work of Oswald Spengler and Arnold Toynbee, world historians whose views were influenced by Greek thought.
Since the 19th century, research in disciplines such as archaeology significantly expanded our empirical knowledge of former societies and civilizations. Consequently, the issue of collapse has yielded to more informed deliberation, as evidenced in the PBS production:
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Human societies and political organizations, like all living systems, are maintained by a continuous flow of energy. From the simplest familial unit to the most complex regional hierarchy, the institutions and patterned interactions that comprise a human society are dependent on energy. At the same time, the mechanisms by which human groups acquire and distribute basic resources are conditioned by, and integrated within, sociopolitical institutions. Energy flow and sociopolitical organization are opposite sides of an equation. Neither can exist, in a human group, without the other, nor can either undergo substantial change without altering both the opposite member and the balance of the equation. Energy flow and sociopolitical organization must evolve in harmony.
Not only is energy flow required to maintain a sociopolitical system, but the amount of energy must be sufficient for the complexity of that system. Leslie White observed a number of years ago that cultural evolution was intricately linked to the quantities of energy harvested by a human population. The amounts of energy required per capita to maintain the simplest human institutions are incredibly small compared with those needed by the most complex. White once estimated that a cultural system activated primarily by human energy could generate only about 1/20 horsepower per capita per year. This contrasts sharply with the hundreds to thousands of horsepower at the command of the members of industrial societies. Cultural complexity varies accordingly. Julian Steward pointed out the quantitative difference between the 3,000 to 6,000 cultural elements early anthropologists documented for native populations of western North America, and the more than 500,000 artifact types that U.S. military forces landed at Casa Blanca in World War II. More complex societies are more costly to maintain than simpler ones, requiring greater support levels per capita. As societies increase in complexity, more networks are created among individuals, more hierarchical controls are created to regulate these networks, more information is processed, there is more centralization of information flow, there is increasing need to support specialists not directly involved in resource production, and the like. All of this complexity is dependent upon energy flow at a scale vastly greater than that characterizing small groups of self sufficient foragers or agriculturalists. The result is that as a society evolves toward greater complexity, the support costs levied on each individual will also rise, so that the population as a whole must allocate increasing portions of its energy budget to maintaining organizational institutions. This is an immutable fact of societal evolution, and is not mitigated by type of energy source. |
Tainter subsequently asserts:
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It is the thesis of this chapter that return on investment in complexity varies, and that this variation follows a characteristic curve. More specifically, it is proposed that, in many crucial spheres, continued investment in sociopolitical complexity reaches a point where the benefits for such investment begin to decline, at first gradually, then with accelerated force. Thus, not only must a population allocate greater and greater higher amounts of resources to maintaining an evolving society, but after a certain point, highter amounts of this investment will yield smaller increments of return. Diminishing returns, it will be shown, are a recurrent aspect of sociopolitical evolution, and of investment in complexity.
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Tainter illustrates growth in benefits relative to costs with the following curve (Figure 19):
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An abbreviated discussion of Tainter's diminishing returns curve is contained in his essay "Complexity, Problem Solving, and Sustainable Societies" [click on the diminishing returns curve for an explanation].
This graphic representation highlights the combined effect of resource stock drawdown and transformation into assets (infrastructure and artifacts) in conjunction with population growth - the conditions for sociopolitical complexity associated with Tainter's focus on diminishing returns.
As an example of collapse, consider a timeline for Chaco Canyon (previously summarized in the discussion of Drawdown » Overshoot » Collapse):
Suggested reading: Jared Diamond's Collapse:
