Gaia
Adrián Santamaría and Jesús Pinto
The Gaia hypothesis has caused a revolution in contemporary ecology. However, to gauge its scope one needs to distinguish and delve deeper into the twofold role it plays. On the one hand, we find its restricted meaning as a scientific hypothesis. This is how it appeared in the 1960s, when James Lovelock was working with NASA on the possibility of life on Mars (de Castro, 2019, p. 35). What led him from there to formulate the Gaia hypothesis was the conduct of a mental experiment (Latour, 2017) which made him realise that “the mere presence [of life on Mars] would radically modify the [current] properties of the [planet’s] environment” (de Castro, 2019, p. 35). Thus, the English meteorologist began to form a different idea of the Earth, endowing it with a specific character with respect to the rest of the planets in the Solar System (in particular) and the infinity of the Universe (in general). Later, in 1979, he published a book in which he developed his new perspective (Lovelock, 1979), proposing for the first time the Gaia hypothesis: “all organisms can be seen to form a single living system, maintaining atmospheric conditions for its benefit” (de Castro, 2019, p. 36). This early formulation received the name proposed by William Golding, 1983 Nobel Laureate in Literature: “Gaia”.
Nevertheless, it was Lynn Margulis who, having reached similar conclusions by other means, enlarged the theory with the consideration of microbial life and genetics. Her theory of “symbiogenesis” posits the origin of all eukaryotic life in the symbiotic relationships among prokaryotic cells, giving rise to all the key organelles for complex life (mitochondria, chloroplasts, cell nuclei) and the innovation of a new genetic information storage molecule (DNA). It was, precisely, from the question on the origin of life and the variability among species that Margulis arrived at the idea of Gaia, whose response was to posit the primacy of symbiosis over competition (Margulis and Sagan, 2003). This perspective revealed the complexity of relationships among living beings: the variations giving rise to evolution were not only due to exchanges of genetic material among different species in terms of interdependence and collaboration (Margulis and Sagan, 2003), but life itself could be depicted as a set of symbiotic relationships (serial endosymbiosis) and, in their multicellular phase, as the prevalence of holobionts (organisms made up of several species in which one acts as host while others co-exist in symbiosis, e.g., human beings and their biota) and their interdependence (Puche, 2018, p. 38). This was just a step away from a description of ecosystems or the biosphere by means of these same tools, whose provenance is the microbial field: “Lynn gave us a bottom-up view of Gaia through her microscope and showed that it was made up of microorganisms and alive.” (Sagan, 2014, p. 52). Gaia was simply symbiosis viewed from space (Puche, 2018, p. 85), i.e., the attestation of ecodependence.
Gaia is a revolutionary hypothesis because it maintains a tense relationship with one of biology’s central paradigms: Neo-Darwinism. From the outset, we find two weak versions of this hypothesis that are only a little awkward to fit this paradigm. Firstly, the “co-evolutionary” hypothesis recognises Gaia as the result of life and the environment having co-evolved, which can be explained by conventional Neo-Darwinist theory. Next to this, the “homeostatic” hypothesis is accepted by Neo-Darwinism regardless of whether it is believed that Gaia exists by chance, or it is granted that, as well as the natural selection of organisms, there is “a selection at a higher level that determines the homeostasis and stability observed in the biosphere” (de Castro, 2013, p. 114). These two ‘weak’ versions of Gaia are accompanied by two ‘strong’ ones: the optimising Gaia “establishes that the biosphere maintains the environment in optimal conditions for life, perhaps out of the need to apply the laws of thermodynamics to living beings and the biosphere” (de Castro, 2013, p. 114) and the organic theory that contemplates Gaia as a super-organism. This last hypothesis seems incompatible with Neo-Darwinism.
Lovelock’s stance, in view of the criticism received, varied substantially over the years, until eventually upholding a cybernetic version of the hypothesis that is compatible with Neo-Darwinism. Of the three scientists mentioned above, only Lynn Margulis, with some nuances, and Carlos de Castro, fully, strongly supported his ideas. Some of their criticism was due, for instance, to the fact that Gaia implies the presence of teleology (referring to an end or purpose) in explaining living processes. Countering this criticism is the argument that a sufficient understanding of the natural selection hypothesis (key to contemporary biology) implies some acceptance of teleology, since this, from its Darwinist formulation, requires the assumption of a certain goal-orientation, or teleonomy: organisms will not vary to adapt to their environment, but a process will unfold that is anticipated by the environment and evolution will follow it through. The mechanism that enables this negotiation between the environment and organisms, providing a vector for ends that do not entail necessity, is, of course, the survival of the fittest. Ends that are conceived not as a necessity or an obligation, but rather as boundaries to variation, whatever this might be (to Darwinism this is completely random), are admissible in evolutional biology. Hence Gaia could be formulated as a mechanism similar to the survival of the fittest maxim, all the more so when considering community evolution as proposed by Lewontin (2000).
Subsequently, further specific critiques appeared, such as that by Doolittle, who, in line with the first general criticism, points to the impossibility of unconscious organisms having the ability to consciously plan and foresee the regulation of the planet (de Castro, 2019, p. 47). Likewise, Dawkins’ critique rejected the idea of the biosphere as a unit of selection, on the grounds that it lacks other organisms against which to fight for existence (de Castro, 2019, p. 48). Stephen Jay Gould, for his part, berated the Gaia hypothesis for lacking an explanatory mechanism, and qualified it as a mere metaphor (de Castro, 2019, p. 51). Lastly, Maynard-Smith highlighted the unavoidable difficulty between organisms’ local optimisation in their fight for existence and the global optimisation of the biosphere by selfish individuals (de Castro, 2019, p. 55). All these critiques can be answered more or less successfully through the different variants of the Gaia hypothesis. Indeed, Doolittle (2019) has currently begun to concede a degree of acceptability to this hypothesis.
Furthermore, Gaia performs as a philosophical concept, since the scientific hypothesis has ethical and political consequences. Some authors (Latour, Haraway or Stengers, among others), far from viewing this in a negative light, see it as proof of the unsustainability of the inherited conception of science. This conception comprises a clear separation between judgements of fact (purely objective, verifiable, and concrete, independent of any opinion) and judgements of value (subject to contingencies and a personalised approach). In contrast with this view of things, the possibilities Gaia offers would reveal that the line between description and prescription is not as clearly defined as we thought. Scientific facts can open up a path for different lines of action: we find facts moving, suggesting, and so on. Thus, the “intrusion of Gaia” (Stengers, 2017) is an invitation to challenge the very concept of “scientific hypothesis”, which would imply a degree of porousness, at least, between the concepts of “ecology” as a science and “ecologism” as a political movement. In parallel, imagining the scientist as someone capable of venturing into the cold world of natural events and coaxing them to speak, while remaining a “modest witness”, should also be critiqued and reviewed. By contrast, Haraway has proposed the idea of a “queered modest witness” (Haraway, 2019), in which such a witness would always be present somewhere (in a laboratory, observatory or office) and would, therefore, be interdependent. From this point of view, Gaia is a concept that is always plural: neither bigger nor smaller than the institutions and the players that give her a voice.
Locating scientific knowledge and reviewing the modes in which it is produced also implies bringing into question (in a negative key) and exploring (in a positive vein), the field of Modernity (Latour, 2007, 2017): the relationships among art, science, law, humanities, and even religion. After all, Lynn Margulis, besides being a scientist, has also written stories based on her hypotheses. The same is also true of Carlos de Castro. Similarly, there has been no shortage of artists approaching the Gaia concept, as well as in the Anthropocene (Latour and Weibel, 2020) (Davis and Turpin, 2015). The legal sphere, for its part, has likewise shown some interest in Gaia: for example, debates are held over the rights of nature, the ecology of law, and ecological law. Lastly, the role of the ecological humanities as a way of acknowledging and contributing to these conspiracies or unexpected relationships, is another point many authors have dwelt on, and particularly in their relationship with another similar concept: the environmental humanities.
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