To recap: The stronger formulations of the Gaia hypothesis have been authoritatively debunked, but the weaker formulations remain intact. For more, read Gaia Is Dead and Long Live Gaia.
Toby Tyrrell, author of On Gaia, finds in favor of a coevolutionary hypothesis, the notion that life and the environment are “somehow coupled.” This hypothesis is equivalent to what James Kirchner labels coevolutionary Gaia.
A brief review of the literature
Peter Ward writes that coevolutionary Gaia is “already viewed as true,” that it is “virtually no hypothesis at all.”
In a similar vein, Arthur C. Petersen holds that the weaker formulations of the Gaia hypothesis are really just “basic assumptions,” from the view of Earth systems science.
Kirchner holds that coevolution between biota and environment “is not original or unique to Gaia,” tracing the idea back to 1844 — long before James Lovelock published the Gaia hypothesis. Kirchner calls coevolution a “fact,” one that is so widely recognized that “it would seem odd to call it a hypothesis.”
What’s in a name
One question that seems to remain is that of nomenclature. Are the weaker forms of Gaia worthy of the name Gaia at all?
Tyrrell doesn’t think so. He writes that attaching the coevolutionary hypothesis to the name Gaia “only generates semantic confusion,” as this form of the hypothesis haven’t been used in any major Gaian publication. Clearly, Tyrrell has not read Primavesi’s Sacred Gaia, which concentrates on a coevolutionary model, but in fairness her theological work would seem to be outside his scope.
If Tyrrell’s work is well-received in the scientific community, the name Gaia may fall from favor as a label for any credible model of how the Earth works. But the Gaia hypothesis is notable for being known and discussed well outside of the scientific community.
This question of naming would seem to be a matter of poetry rather than strict scientific nomenclature. Lovelock originally wanted to call his idea the “Earth feedback hypothesis”; the name Gaia is credited to the novelist and poet William Golding. It’s doubtful that Lovelock’s work would have captured the public’s imagination without this poetic license.
We might do well to inquire into the overall value of the name Gaia in the context of our modern understanding of the Earth and our relation to it. As a metaphor, Kirchner says, Gaia is “unusually rich, colorful and evocative.” In a splendid recent essay, Michael Ruse writes that “even if Gaia is not literally true, it is a metaphor worth cherishing.” The name Gaia has increased general interest in a holistic view of the Earth and its systems. Gaia can inspire feelings of gratitude, reverence and mature responsibility. That is positive.
But the name Gaia may also confuse people. The powerful image of the ancient mother goddess may lead to muddled thinking and a complacent mindset. People may lose sight of a weaker coevolutionary model and gravitate toward the stronger homeostatic and teleological models. People may think “Gaia will protect us” though the evidence does not support such hope.
It is possible to hold an image of Gaia that is both resonant with ancient wisdom and consonant with current scientific thinking. But is this an esoteric exercise limited to an intellectual elite? Can such an image capture the popular imagination?
What do you think? If you have any thoughts on the subject, please leave a comment.
“The Gaia Hypothesis: Can It Be Tested?” by James W. Kirchner
The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive? by Peter Ward
Sacred Gaia : holistic theology and earth system science by Anne Primavesi
On Gaia : a critical investigation of the relationship between life and earth by Toby Tyrrell
“Earth’s Holy Fool?” by Michael Ruse
“Models and Geophysiological Hypotheses” by Arthur C. Petersen in Scientists Debate Gaia: the next century