Gaia
First articulated by the British chemist James Lovelock in the 1970s, the Gaia hypothesis (named for the Greek goddess who personified the earth) proposes that the biosphere, atmosphere, oceans, and surface rocks make up a single, self-regulating, homeostatic system (Lovelock 1979). Key observations that Lovelock used in support of Gaia include the long-term stability of chemical disequilibria in the atmosphere and oceans despite both high fluxes of many chemicals within the earth system, and the fact that these persistent (in some cases for billions of years) yet nonequilibrium conditions are particularly well-suited for life as it has evolved. To Lovelock, the implication of these and related observations is that the biosphere must actively modulate the chemical make-up, temperature, pH, and other attributes of the earth system in order to maintain conditions under which life can flourish. In particular, the composition of the atmosphere must be regulated by the biosphere to maintain near-optimal concentrations of chemicals such as hydrogen, oxygen, and nitrogen.
Lovelock and his followers have promoted Gaia as an integrative framework for the study of the earth system. It raises scientific questions and demands experiments that would not be recognized under the traditional disciplinary and reductionist regimens dominant in the earth and environmental sciences. Gaia is thus not only an attempt to specify a unifying framework for the operation of the entire earth system, but also an explicit critique of the existing organization of knowledge inquiry.
Gaia has had little effect on research agendas, however, and the number of working scientists willing to be associated with the hypothesis is small—perhaps less than a dozen. Critique of the hypothesis focuses on three lines of argument. Gaia is said to be tautological because it asserts that life exists under exactly those conditions that are suitable for life. It is said to be teleological because it implies that the earth system must have evolved according to a design concept. And it is said to be trivial because, even so, Gaia adds little to existing knowledge about feedbacks among physical, chemical, and biological processes (Kirchner 2002). In response it is argued that Gaia is an emergent phenomenon that cannot be understood through traditional, disciplinary, and reductionist cause-and-effect reasoning. Lynn Margulis, a forceful advocate of Gaia, suggests: "The Gaian viewpoint is not popular because so many scientists, wishing to continue business as usual, are loath to venture outside of their respective disciplines. At least a generation or so may be required before an understanding of the Gaia hypothesis leads to appropriate research" (Margulis and West 1997, p. 223).
But it remains to be seen if the type of interdisciplinary synthesis that Gaia demands is even possible. Interdisciplinarity founders not just on the administrative boundaries between disciplines, but also on the differences in subject, method, time and spatial scales, types of data, definition of problems, and criteria of proof among various disciplines. These differences cannot easily be transcended or reconciled. This disunity of science is not entirely capricious, but in part reflects the richness and diversity of nature. How actually to move from reductionism and disciplines to Gaian synthesis remains far from clear.
Indeed while the need for interdisciplinarity is accepted by many scientists, strategies in the early twenty-first century—exemplified by the construction of highly complex, mathematical models aimed at simulating the coupled ocean-ice-atmosphere system—are still essentially reductionist in nature, building a story from first principles and supporting bodies of observational data. Gaia's claim is that such approaches can no more yield a comprehensive understanding of the earth system than a mapping of synapses can reveal the workings of an individual's consciousness.
Thus at least at this point in the evolution of science and society, Gaia's greatest impact may be largely metaphorical. On one level this metaphor may continue to challenge science to engage nature more synthetically, just as the Cartesian metaphor of nature as a clockwork helped to advance the cause of reductionist science. But on a broader, societal level Gaia has already been embraced as a cautionary symbol of the earth's complexity, interconnectedness, and inscrutability. Wrote Václav Havel, "Our destiny is not dependent merely on what we do for ourselves but also on what we do for Gaia as a whole. If we endanger her, she will dispense with us in the interests of a higher value—that is, life itself" (Havel 1998, p. 171).
Earth;; Earth Systems Engineering and Management;; Ecology;; Environmental Ethics;; Environmentalism.
Bibliography
Havel, Vaclav. (1998). "The Philadelphia Liberty Medal." In The Art of the Impossible. New York: Fromm International.
Kirchner, James W. (2002). "The Gaia Hypothesis: Fact, Theory, and Wishful Thinking." Climatic Change 52: 391–408. A spirited scientific (as opposed to espistemological) critique of the Gaia hypothesis.
Lovelock, James E. (1979). Gaia: A New Look at Life on Earth. Oxford: Oxford University Press. The most complete treatment of the hypothesis, by its creator.
Margulis, Lynn, and Oona West. (1997). "Gaia and the Colonization of Mars." In Slanted Truths: Essays on Gaia, Symbiosis and Evolution, ed. Lynn Margulis and Dorian Sagan. New York: Copernicus.
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