The myth of nature as a self-regulating ecosystem

January 16, 1996|By Alston Chase

IN MANY CULTURES, beliefs about nature form the bedrock of what people believe about ethics, politics and social life.

One might cite as examples the natural-law tradition that dominated political thinking during the Middle Ages, the state-of-nature theories of the Enlightenment or the evolutionary theories of the 19th century. For much of American history, the dominant political consensus could be traced to British philosopher John Locke's ideas about a rational humanity and a benevolent nature.

Whenever people come to doubt the most fundamental assumptions of their political beliefs, they tend to go back to nature to find new foundations. So it was with the generation that came of age in the 1960s as it looked for answers to the pressing problems of civil rights, the war in Vietnam and the environment.

Searching for something to replace the Lockean consensus, that generation embraced the metaphor of nature as an organized ecosystem of self-regulating feedback loops.

The concept of biodiversity

Under that metaphor, biodiversity became a crucially important concept. The health of the entire ecosystem depended on the proper functioning of all its diverse parts. As long as it was free of outside perturbations, the system would enjoy a relative equilibrium.

The loss of biodiversity (through the extinction of species, for example) could cause the system to become more vulnerable to perturbations; if it lost enough diversity and suffered sufficiently violent perturbations, it might even suffer what Barry Commoner termed an ''ecological collapse.''

The spirit of that metaphor infused virtually all the environmental policies and laws of the 1960s and 1970s (most of which remain on the books today), including the Endangered Species Act, the Wild and Scenic Rivers Act, and the National Parks Management Act. In 1968 the National Park Service was the first federal agency to introduce ecosystems management; today, virtually every land-management agency has adopted it. The metaphor also directly led to the political or ethical doctrine of biocentrism, the idea that the needs and interests of ecosystem take precedence over those of individuals.

For most of the 20th century, two streams of thought fed environmentalism; preservationism and conservationism.

Preservationism, derived from an indigenous American pantheistic tradition extending from Jonathan Edwards, Ralph Waldo Emerson and Henry David Thoreau to John Muir, Rachel Carson and Aldo Leopold, promoted policies of absolute noninterference with a sacred nature.

Conservationism, espoused by such figures as Theodore Roosevelt, sought to manage nature for human benefit.

By the 1960s, however, a third intellectual tradition had infused environmental reasoning: a systematic metaphysics that originated with the German philosopher G.W.F. Hegel. The influence of Hegel's doctrine that the whole is larger than the sum of its parts can be seen in policies of the Office of Naval Research and the Atomic Energy Commission, which began funding systems ecology to learn how to protect human populations from the dangers of atomic radiation.

The concept of a stable nature is an attractive one. But does it correspond to the evidence?

The mathematics of the models scientists used in the 1960s demanded both the assumption that ecosystems tend toward equilibrium when left undisturbed and the assumption that greater diversity leads to greater stability. Over the past 25 years, however, most ecologists in the United States have largely rejected the notion of nature's being stable or tending toward balance.

Here is how the New York Times reported the consensus view of one 1990 meeting of the Ecological Society of America:

''The concept of natural equilibrium long ruled ecological research and governed the management of such natural resources as forests and fisheries. It led to the doctrine popular among conservationists that nature knows best and human intervention in it is bad by definition.

Change and turmoil

''Now an accumulation of evidence has gradually led many ecologists to abandon the concept or to declare it irrelevant, and others to alter it drastically. They say that nature is actually in a continuing state of disturbance and fluctuation. Change and turmoil more than constancy and balance is the rule. As a consequence, say many leaders in the field, textbooks will have to be rewritten and strategies of conservation and resource management will have to be rethought.''

The notion of nature as a self-regulating ecosystem is what philosophers call a teleological concept: a belief that things in nature happen the way they do to achieve certain ends. To truly know a thing is to know its end. The classic example of such thinking is Aristotle's Metaphysics, which dominated European thought until the 17th century.

The idea of nature as self-regulating ecosystem lends itself to the teleological doctrine of biocentrism, the view that there is such a thing as a health of nature that needs preserving.

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