Gaia is dead. Long live Gaia!
The Gaia hypothesis is one of those bold proposals that has captured the imagination of the general public. It has been embraced and celebrated well beyond the domain of conventional science. Gaia has been held to have deep spiritual ramifications.
Such matters are beyond the scope of Toby Tyrrell’s recent book, On Gaia (review) which offers a devastating critique of the Gaia hypothesis. Yet for those who have taken the Gaia hypothesis to heart, who have found it a source of inspiration and wonder, it’s important to discern what exactly Tyrrell has discounted and what he has not.
As Tyrrell points out, Gaia is “not a well-defined concept.” He cites the work of James Kirchner, who identified no less than five variations on the hypothesis, ranging from weak to strong.
(1) influential Gaia, which asserts only that biology affects the physical and chemical environment to some degree; (2) coevolutionary Gaia, which limits itself to stating that the biota and environment are somehow coupled; (3) homeostatic Gaia, which emphasizes the stabilizing effect of the biota; (4) teleological Gaia, which implies that the biosphere is a contrivance specifically arranged for the benefit of the biota; and (5) optimizing Gaia, which suggests that the biosphere is optimized in favor of the biota.
As one might imagine, the stronger versions of Gaia are more controversial. The two strongest forms have been abandoned even by James Lovelock, the originator of the hypothesis, while the two weakest forms are deemed largely uncontroversial. Therefore it’s the middle version, the question of homeostatic Gaia, which constitutes the prime interest of Tyrrell’s work.
Far from debunking all five versions of the Gaia hypothesis, Tyrrell to the contrary finds in favor of a coevolutionary hypothesis, the notion that life and the environment are “somehow coupled.” This hypothesis is equivalent to what Kirchner labels coevolutionary Gaia.
Thus, while the idea of a strong, self-regulating Gaia may be in question, the concept of an evolutionary coupling between living creatures and the environment is not.
One of the most comprehensive and thoughtful treatments of Gaia’s implications for religion and spirituality may be found the work of Anne Primavesi. Her book Sacred Gaia, published in 2000, is a radical reappraisal of Christian theology in light of Earth system science.
As such, it is instructive to inquire as to which model of Gaia informs Primavesi’s writing. What vision drives her work along? Does she place importance on the purported homeostasic and regulatory effects of Gaia? Does she portray Gaia as an optimizing force that keeps the Earth “comfy” for us?
Indeed not. Primavesi writes almost exclusively about a coevolutionary Gaia (to use Kirchner’s term). She describes Gaia as “the planet-sized system where the living and non-living components interact as two tightly coupled forces, each one shaping the other through systemic feedback loops.” Amongst the significant implications of this fact, she finds that “a Gaian perspective… does not support a view of ourselves in radical discontinuity with other species. On the contrary, our common origins with other multicellular organisms bind us ineluctably to past and present communities of life forms on earth.” Coevolutionary coupling means that we are situated in a web of interdependent relations, and this realization has profound moral consequences.
The awakening to such dependence is disorienting to a species which has believed and preached that God has given it dominion over all living creatures. Or, in a secular version, that our brains/technology/higher consciousness have given us the ability to dominate every other life form and the right to exercise that dominion.
This is a radical revisioning of Western thought. However, it does not call upon the more radical formulations of the Gaia hypothesis for support.
To state the matter bluntly, Tyrrell’s debunking of homeostatic Gaia does no damage to Primavesi’s thesis.
This is but one example. The effects of Tyrrell’s critique will vary according to one’s thealogy. If one is seeking scientific support for the comforting metaphor of an all-powerful Earth Mother who protects herself from the vagaries of the cosmos (and the depredations of humanity) then Tyrrell brings bad tidings indeed. On the other hand, a metaphor of Gaia in process, striving with us and through us to make a better world, remains as a source of both inspiration and spiritual sustenance.
It should also be noted that, despite Tyrrell’s critique of Gaia, the Earth remains a coherent whole, a complex of interconnected systems. This may be the substantial and lasting scientific contribution of Lovelock and his collaborators. The holistic view is now taken as a given, as the bedrock foundation for Earth system science.
Next week: Is a coevolutionary Gaia worthy of the name Gaia at all?
The Gaia Hypothesis: Can It Be Tested? by James W. Kirchner
Sacred Gaia : holistic theology and earth system science by Anne Primavesi