A good case can be made that life is an inherently planetary phenomenon. If correct, this proposition implies that any extra-terrestrial life will necessarily co-occur with planetary scale chemical/climatic disequilibrium. But life's fundamental sense-making principle, Darwinian evolution by natural selection, operates far below the planetary scale, within populations of organisms (or genes, groups, etc.). This spatio-temporal disconnect means that the question of whether Darwinian evolution tends to stabilize or destabilize Earth's climatic habitability, is one that remains almost completely unanswered.
This question is intertwined with the long history of debate within Darwinism pertaining to long-term trends in biological complexity and diversity, and the relative importance of permissive environments versus within-biosphere innovation in driving macro-evolutionary trends.
Recent attempts to bridge this gap and potentially "Darwinize Gaia" (or at least fully explore the implications of heterodox forms of selection at an Earth system scale) invoke persistence-based selection at the level of biogeochemical cycle-variants. But a sticking point has been the derivation of a non-arbitrary definition of the differentially persisting entities that this process involves. We propose that this can be rectified by defining cycle-biota-variants (CBVs) in terms of a geochemical/climatic "field", within which such CBVs are contained, and that both influences and is influenced by their relative persistence. We believe that the appropriate theoretical approach is a fusion of Doolittle's "It's-the-song-not-the-singers" theory (above) and McShea's field theory (co-investigator in this project).
We hope to derive such an account through a combination of theoretical biological modeling, philosophy of biology, and Earth system modeling, thereby deriving a theoretical framework for a "Darwinized" Gaia.
