October 24th, 2011
“In this essay, the sigmoidal curve will be used as a ‘thinking tool’ and as a symbol. Its shape reflects a law of nature that governs growth in living systems, and reflects the transformational character of change in our time” (p3).
The sigmoidal curve (p3).
“In this figure, and in those that follow, the horizontal axis represents time and the vertical axis represents number. In the first, upturned portion of the curve, population growth follows a pattern of acceleration; in the second part, growth decelerates and a plateau is reached. The gap in the curve emphasizes the point of inflection—the point of change from accelerating growth to decelerating growth” (p3).
“For thousands of years before agriculture, human population increased very slowly. In response to environmental adversity and population pressures, agriculture emerged, making more food available to support greater numbers of human beings. A pattern of gradual increase thus continued throughout the agricultural period. In the last several centuries, scientific, technologic, and industrial developments have further raised the carrying capacity of the plant, contributing to the recent sharp rise in population” (p27).
Human population trends (p27).
However, rates of human population growth, birth and death rates, fertility rates, population distributions by age and sex, median age, life expectancy, sex ratios, child/woman ratios, and other data suggest that the human population growth curve will follow a sigmoidal pattern. As well, “except for the sun as a constant source of energy, the earth can be seen as a closed system and, by inference from the examples given [of animal and yeast population growth in closed systems], we can expect the human population growth curve to follow a sigmoid pattern” (p23).
The following figure “shows the estimated increase in world population size in the period 1750 to 1975, with medium projections to the year 2200. This figure… illustrates the sigmoid pattern of human population growth and the estimated plateau at approximately 10.5 billion people. The high and low variants for the year 2125 are 14.2 and 8.0 billion respectively. The inflection of worldwide growth will become evident at about the turn of the century” (p64).
World population size (medium variant), 1750-2000 (p65).
From a longer-range perspective, the figure below “schematically describes the course of human population growth and population growth rates over a period extending from 8,000 years in the past to 8,000 years in the future. The curve indicates a plateau of world population at approximately 11 billion by the end of the twenty-first century and assumes that this level will remain or slowly decline” (p66).
World population size and rate of growth, 6500 B.C. to 9500 A.D. (p67).
“If these estimates and assumptions are valid, we can see that the present extended period of rapid population growth is unique when seen from a long-range perspective; it has never occurred before and is unlikely to occur again” (p66). “Intuitively, we sense from this image that, from a psychological and social standpoint, human beings may be better adapted to conditions associated with less rapid change (like those that existed in the more distance past and that are anticipated in the coming centuries) than they are to those that we presently experience” (p130).
“We use the sigmoid curve not only to represent numbers of human beings but also to provide a frame of reference for discussing the nature of human values, attitudes, and behavior before and after the point of inflection” (p73). “The difference in shape between the two portions of the curve suggests both quantitative and qualitative differences in human life between the two periods of time. It not only indicates differences in population growth patterns but also suggests differences in the characteristics of prevailing conditions and in the quality of human life in the two periods” (p74).
“In this figure, the two parts of the curve before and after the point of inflection have been separated for emphasis. One is designated as A and the other as B. The periods of time prior to and following the point of inflection are referred to as Epoch A and Epoch B, respectively” (p77).
Epoch A and Epoch B (p77).
“From the shape of the A curve, the future would appear to be unlimited in terms of growth and expansion of, for example, population, resources, and availability of energy. To someone born in Epoch B, however, the future would seem to be a time of multiple limitations with a ceiling on growth and expansion. The difference in shape between the two curves thus implies that there will be a fundamental, qualitative difference in circumstances between the two periods of time” (p77).
For example, “during Epoch A, because mortality rates were high at all ages, the control of disease and of premature death were of primary concern. Success in this regard has contributed to the recent sharp increase in population size. As a result of this, the concern in Epoch B can be expected to shift to the control of fertility and to a preoccupation with the enhancement of health” (p80).
Values of health in Epoch A versus Epoch B (p81).
Other changes in values and attitudes discussed by Salk include:
|Epoch A Values||Epoch B Values|
|quantity of children||quality of children|
|persistent expansion of societies and industries||dynamic equilibrium|
|extremes in growth and development||balance|
|competition, independence, power||collaboration, interdependence, consensus|
|either/or, win-lose||both/and, win-win|
|present, short-range, parts||future, long-range, whole|
“This is a change from seeing the world as limitless in terms of growth to seeing it as limited. It is also a change from seeing ourselves in opposition to each other to seeing ourselves in collaboration with one another. It is due not only to a change in perception but to a necessary change in human attitudes and spirit that comes in response to a change in reality, as expressed by the shapes of the curves. The change from A to B can be seen in relationships to nature, our relationships to each other, and in our relationships to ourselves” (p94).
“Human beings possess the capacity for a wide range of attitudes and behavior. The idea underlying the preceding discussion is that those attitudes and behavior that are advantageous and therefore appropriate under one set of circumstances (the reality of Epoch A) may be disadvantageous and inappropriate under another (the reality of Epoch B)” (p101).
“In the region of inflection growth rates are highest, acceleration is changing to deceleration, and values are shifting most rapidly. This period can be expected to be a time of increased conflict” (p101).
The process of inversion of values (p111).
In the above figure, “the relative position of the two lines indicates that Epoch B values exist even in the period before inflection, but are less dominant than Epoch A values. In Epoch B, the relative dominance is reversed… [This] offers an explanation for the tension we feel at this time. It suggests that the conflicts are an inherent part of this developmental and evolutionary process. They are not necessarily a signal of an impending end of the human species but reflect the process of inversion that is now occurring” (p110).
“In the process of adapting to changing conditions, conflict may be most effectively resolved, as symbolized [below], with a both/and approach. For example, completely disregarding the technological and social developments of Epoch A in an effort to immediately halt growth would be inappropriate and unrealizable. On the other hand, attempting to resolve tensions by completely suppressing the tendencies of Epoch B would be equally disadvantageous. With a both/and approach, the developments that have been part of Epoch A can be combined with Epoch B values in order to develop solutions that are appropriate to changing conditions. A specific example of this might be the simultaneous short-term reliance on nonrenewable resources of energy with the long-term goal of reducing consumption and of developing efficient means for using renewable resources” (p112).
Resolution of tensions (p113).
“The patterns revealed in the preceding figures suggest that differing tendencies that have always been present in human beings have diverged in the course of the rapid changes of more recent history” (p134). For example, “at present, the tendency to make decisions based purely on material costs and benefits are in conflict with the tendency to base decisions on human considerations, such as quality of individual health or the quality of the physical environment. In contrast, economic decisions in the future will increasingly take into account both human and material value. The change will affect the nature of economic relationships and organizations in the years ahead” (p138).
Material value versus human value (p139).
“At this point, innovation in the area of human development and social relationships is as important as the advent of agriculture 10,000 years ago, or the understanding of microbes and machines in the past century. Just as some of the brightest minds of recent years turned their attention to the advancement of science and technology and to the prevention and cure of disease, many of the brightest minds of coming generations will turn their attention to the phenomenon of the human mind and the improvement of the quality of human life” (p164).