Tuesday, August 18, 2009

5. The Gaia Hypothesis

Darwin's perspective on the origin of species is useful to us because it is non-deterministic, non-teleological, and ecocenteric. In Darwin's "tree of life" Homo sapiens are not at the top of the pyramid but on the same evolutionary level as other life forms. In fact, from an evolutionary perspective Homo sapiens are yet to prove their fitness the same way sharks or other species with much longer history have.

The Gaia hypothesis (names after the Greek mythology supreme goddess of Earth) proposed by James Lovelock, provides further context for reflection on Our Place in the World. A British scientist, in the 1960s Lovelock served as an independent consultant for NASA in planning for the Viking mission to Mars. NASA was interested to learn about how best to determine if there is life on Mars.

Lovelock realized that one does not need to land on Mars to know if there was life on it. Atmospheric conditions on Mars (carbon dioxide 95%, oxygen 0.13%, nitrogen 2.7%), stable for very long time, precluded existence of life, as we know it on Earth. Lovelock then asked what are the preconditions of life on Earth? Using a chemical model of Earth without any life forms (no photosynthesis or respiration), he found that carbon dioxide would be 98% (currently 0.03%), oxygen barely detectable (currently 21%), and nitrogen less than 2% (currently 79%). Furthermore, such a lifeless Earth would be very hot at 554F/290C with atmospheric pressure 60 times of what exists today.

Lovelock defined Gaia as a complex entity involving the Earth's biosphere, atmosphere, oceans, and soil, the totality constituting a feedback or cybernetic system, which seeks an optimal physical and chemical environment for life on this planet.

Columbia University ecologist, Shaheed Naeem, explains it in simpler terms:

Lovelock came away with a sense that there was something truly remarkable about Earth, a sort of meta-life or gigantic global biological system in which the sum of the parts--all the plants, animals and microorganisms--made Earth the habitable planet that it was. He speculated that it was an autopoietic system, meaning (roughly) that all its species actively contribute to the functioning of the biosphere in such a way as to ensure their growth and regeneration, which, in turn, is what governs biospheric functioning. This is a complex idea, but essentially he felt that life actively holds the conditions of Earth's surface within a range conducive to the persistence and perpetuation of life, a homeostasis similar to our bodies' regulation of core temperature to a constant of around 37 C (98.6 F).[1]

The Gaia hypothesis was initially ignored or ridiculed by some as some kind of neo-pagan New Age religion. Renowned scientists such as such as Doolittle, Dawkins and Gould criticized it on various grounds (click here).

However, in 1980s the Gaia hypothesis received positive recognition by scientists and a number of scientific conferences have been held to develop and implement it as a research agenda.

Climatologist Stephen Schneider who organized the first Gaia conference in San Diego in 1988 proposed that the Gaia hypothesis includes a range of possible claims. Naeem summarize these as the Weak Gaia Hypothesis that says life is critical to Earth’s environment, and the Strong Gaia Hypothesis that says that the biosphere is autopoietic. He notes:

Though the jury is still out, the bulk of the scientific evidence is against the Strong Gaia Hypothesis. One of its strongest critics is Dawkins, who sees no way that evolutionary or ecological processes can generate an autopoietic biosphere from a seemingly unstructured confederation of species whose fates are determined by their individual fitness or stability of the community, ecosystems or biosphere they reside in. Nevertheless, life is what makes Earth habitable, so the Weak Gaia Hypothesis is undeniable.”[2]

While we wait for the future assessment of the Strong Gaia Hypothesis, the consensus on the Weak Gaia Hypothesis offers materialist and scientific grounds for a view of "web of life" in addition to Darwin's "tree of live". Life on Earth is inherently interdependent. This validates ethical principles of Deep Ecology ’s Eight Point. It also offers a framework for rethinking Marx’s vision of de-alienation of humans from nature.

[1] Naeem, Shahid. “Lessons from the Reverse Engineering of Nature,” Miller-McCune/May-June 2009, p. 60.

[2] Ibid. p. 62. Naeem does not here note Lovelock's response to Dawkins criticism, which is based on complexities in evolutionary process associated with non-linear systems.

Friday, August 7, 2009

4. Darwin's Ecocenterism

The intellectual roots of Deep Ecology are found in ecocenterism and social criticism of Henry David Thoreau, John Muir, D. H. Lawrence, Robinson Jeffers, Aldous Huxley as well as George Orwell, Theodore Roszak, and Lewis Mumford. Cultural history of primal peoples, ecocenteric religions such as Taoism, Zen Buddhism, and writings of Saint Francis of Assisi also influenced it. However, there is a curious lack of attention to Darwin’s ecocenterism. And yet, Darwin’s evolutionary theory is truly revolutionary in that it has provided a solid materialist and scientific basis for ecocenterism.

For centuries, religious belief and philosophical reasoning had placed Earth at the center of the universe. It also took more than 150 years of controversy and confrontation spanning most of the 16th and 17th centuries, from Copernicus’ De revolutionibus orbium coelestium in 1543 to Newton’s Principia in 1687, to revolutionize cosmology. These efforts led to present-day view of an expanding universe that may have millions of life-supporting planets in our galaxy alone.

Darwin’s evolutionary theory laid the groundwork for overcoming centuries of anthropocentric views of life on Earth preached by organized religions and influential philosophers. Naturalists had conceptualized evolution for centuries before Darwin. Greek philosopher Anaximander had suggested that all life-forms evolved from fish in the seas and went through a process of modification once they were established on land. Carl Linnaeus published the first volume of Systema Naturae (1735), which laid the foundation for taxonomy. He later suggested that plants descend from a common source. Darwin’s contemporary evolutionary thinkers believed that evolution unfolded like an ascending ladder in which each lineage of plant or animal arose by spontaneous generation from an inanimate matter and then progressed inexorably toward greater complexity and perfection.

Darwin rejected this linear progression in favor of what is now known as branching evolution, in which some species diverge from a common ancestor along separate pathways with no prior limits to how far this process can go. Darwin sketched a “tree of life” to illustrate this in his book Origin of Species (1859). But how this evolutionary change unfolded? Darwin’s great insight was the theory of natural selection. Taking a cue from Thomas Malthus, Darwin recognized that populations tend to grow quickly thereby exhausting natural resources. From the vast hereditary diversity within a given species, natural selection blindly weeds out those individuals with less favorable traits. That is a design without a designer. In fact, if two populations of one species remain isolated from each other in different environments they may evolve over a very long period into two different species.[i]

The modern version of Darwin theory benefits from the field of genetics that Gregory Mendel’s research on inheritance (published in 1865) founded, and the discovery of DNA by James Watson and Francis Crick in 1953.

Thus, Darwin provided us with a materialist ecocenterist view of life. The prominent evolutionary biologist Ernest Mayr offers a good summary of Darwin’s contributions to modern thought:

“… [H]e established a philosophy of biology by introducing the time factor, by demonstrating the importance of chance and contingency, and by showing that theories in evolutionary biology are based on concepts rather than laws. But furthermore - and this is perhaps Darwin's greatest contribution - he developed a set of new principles that influence the thinking of every person: the living world, through evolution, can be explained without recourse to supernaturalism; essentialism or typology is invalid, and we must adopt population thinking, in which all individuals are unique (vital for education and the refutation of racism); natural selection, applied to social groups, is indeed sufficient to account for the origin and maintenance of altruistic ethical systems; cosmic teleology, an intrinsic process leading life automatically to ever greater perfection, is fallacious, with all seemingly teleological phenomena explicable by purely material processes; and determinism is thus repudiated, which places our fate squarely in our own evolved hands.” (Mayr, “Darwin’s Influence on Modern Thought”, 1999).

The benefit of Darwin’s contributions to Deep Ecology and Marxian theory is immense.

[i] This paragraph is a summary taken from “Darwin’s Living Legacy” by Gary Stix, Scientific American, Volume 300, Number 1, January 2009.