Long Live Gaia

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.

Hope for the planet

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.

Religious Implications

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

On Gaia : a critical investigation of the relationship between life and earth by Toby Tyrrell

Photo: Hope for the planet / CC BY 2.0


Gaia Is Dead

Gaia is dead, and Toby Tyrrell has killed her.

Book Cover

This is a brief review of On Gaia: A Critical Investigation of the Relationship Between Life and Earth by Toby Tyrrell.

It’s a devastating book. Devastating, that is, to the Gaia hypothesis. It’s also quite fascinating. This is recommended reading for anyone who lives on Earth and has a brain.

The author aims to investigate the hypothesis, formulated by James Lovelock in the 1970s, “that life has played a critical role in shaping the planetary environment and climate over ~3 bil­lion years, in order to keep it habitable or even optimal for life down through the geological ages.” (From Q&A with Toby Tyrrell)

Tyrrell offers evidence and argument in roughly equal measure. The empirical evidence is drawn from a diverse array of sources, most notably evolutionary biology and Earth system science. The philosophical arguments include an extended meditation on the anthropic principle and its implications.

For non-scientists, at least, it’s perhaps too easy to dismiss the empirical data. The critical reader, if not familiar with the current research literature, can’t help but wonder if the author is selectively presenting only evidence that supports his agenda. The philosophical arguments can be understood by anyone, regardless of specialization, and are much harder to discount.

On both fronts, in chapter after chapter, Tyrrell finds the case for Gaia doesn’t hold up. He gives credit to Lovelock for major insights that have proven correct, and for generally provoking scientists and the general public to think about life on Earth in a new way. But at the end of the book, Gaia has been thoroughly dismantled.

So where does that leave us? Tyrrell winds up with an excellent discussion on just why all this stuff matters. He points out that any notion of Gaia as a self-sustaining, self-regulating system may lead to complacency. We may be tempted to believe that environmental problems will tend to correct themselves. In other words, Gaia may lead us to “undue optimism.” It’s important for humanity to realize that we cannot rely on built-in safeguards to save our proverbial bacon. The global ecosystems which sustain us are more precarious than a strong Gaian view might lead us to believe. If we are to protect our home from the effects of our own depredations, we must dispense with the erroneous notion of a self-healing Earth.

In other words, in order to save Gaia, it is necessary to destroy her.

Next week: Spiritual and religious implications of Tyrrell’s critique.