Gaia: The Gaia philosophy - an overivew

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Gaia philosophy (named after Gaia, the Greek goddess of the Earth) is a broadly inclusive term for related concepts that living organisms on a planet will affect the nature of their environment - to make it more suitable for life. This set of theories holds that all organisms on a planet regulate the biosphere to the benefit of the whole. The Gaia concept draws a connection between the survivability of a species, (hence its evolutionary course) and their usefulness to the survival of other species.

While there were a number of precursors to Gaia theory, the first scientific form of this idea was proposed as the Gaia Hypothesis by James Lovelock, a UK chemist, in 1970. The Gaia hypothesis deals with the concept of homeostasis, and claim the resident life forms of a host planet coupled with their environment have acted and act as a single, self-regulating system. The system includes the near-surface rocks, the soil, and the atmosphere. While controversial at first, various forms of this idea became accepted to some degree by many within the scientific community.

These theories are also very significant in green politics.

Predecessors to the Gaia theory

There are some mystical, scientific and religious predecessors to the theory, which had a Gaia-like conceptual basis. Many religious mythologies had a view of Earth as being a whole that is greater than the sum of its parts (e.g. some Native American religions).

Lewis Thomas held that Earth should be viewed as a single cell; he derived this view from Johannes Kepler's view of Earth as a single round organism. Teilhard de Chardin, a paleontologist and geologist, believes that evolution unfolded from cell to organism to planet to solar system and ultimately the whole universe, as we humans see it from our limited perspective. De Chardin later influenced Thomas Berry and many Catholic humanist thinkers of the 20th century. Buckminster Fuller is generally credited with making the idea respectable in Western scientific circles in the 20th century. Building to some degree on his observations and artifacts, e.g. the Dymaxion map of the Earth he created, others began to ask if there was a way to make Gaia theory scientifically sound.

Range of views

Gaia theory is a spectrum of hypotheses, ranging from the undeniable to radical. At one end is the undeniable statement that the organisms on the Earth have radically altered its composition. A stronger position is that the Earth's biosphere effectively acts as if it is a self-organizing system which works in such a way as to keep its systems in some kind of equilibrium that is conducive to life. Biologists usually view this activity as an undirected emergent property of the ecosystem; as each individual species pursues its own self-interest, their combined actions tend to have counterbalancing effects on environmental change. Proponents of this view sometimes point to examples of life's actions in the past that have resulted in dramatic change rather than stable equilibrium, such as the conversion of the Earth's atmosphere from a reducing environment to an oxygen-rich one.

An even stronger claim is that all lifeforms are part of a single planetary being, called Gaia. In this view, the atmosphere, the seas, the terrestrial crust would be the result of interventions carried out by Gaia, through the coevolving diversity of living organisms. Most scientists do not hold this view; however, such a view is considered within scientific possibility.

The most extreme form of Gaia theory is that the entire Earth is a single unified organism; in this view the Earth's biosphere is consciously manipulating the climate in order to make conditions more conducive to life. Scientists contend that there is no evidence at all to support this last point of view, and it has come about because many people do not understand the concept of homeostasis. Many non-scientists instinctively see homeostatis as an activity that requires conscious control, although this is not so.

Much more speculative versions of Gaia, including all versions in which it is held that the Earth is actually conscious or part of some universe-wide evolution, are currently held to be outside the bounds of science.

Gaia in biology and science

Buckminster Fuller has been credited as the first to incorporate scientific ideas into a Gaia theory, which he did with his Dymaxion map of the Earth.

The first scientifically rigorous theory was the Gaia Hypothesis by James Lovelock, a UK chemist. While controversial at first, various forms of this idea became accepted to some degree by many scientists.

A variant of this hypothesis was developed by Lynn Margulis, a microbiologist, in 1979. Her version is sometimes called the "Gaia Theory" (note uppercase-T). Her model is more limited in scope than the one that Lovelock proposed.

Whether this sort of system is present on Earth is still open to debate. Some relatively simple homeostatic mechanisms are generally accepted. For example, when atmospheric carbon dioxide levels rise, plants are able to grow better and thus remove more carbon dioxide from the atmosphere, but the extent to which these mechanisms stabilize and modify the Earth's overall climate are not known.

The Gaia hypothesis is sometimes viewed from significantly different philosophical perspectives. Some environmentalists view it as an almost conscious process, in which the Earth's ecosystem is literally viewed as a single unified organism. Some evolutionary biologists, on the other hand, view it as an undirected emergent property of the ecosystem; as each individual species pursues its own self-interest, their combined actions tend to have counterbalancing effects on environmental change. Proponents of this view sometimes point to examples of life's actions in the past that have resulted in dramatic change rather than stable equilibrium, such as the conversion of the Earth's atmosphere from a reducing environment to an oxygen-rich one.

Depending on how strongly the case is stated, the hypothesis conflicts with mainstream neo-Darwinism. Most biologists would accept Daisyworld-style homeostasis as possible, but would not accept the idea that this equates to the whole biosphere acting as one organism.

A very small number of scientists, and a much larger number of environmental activists, claim that Earth's biosphere is consciously manipulating the climate in order to make conditions more conducive to life. Scientists contend that there is no evidence to support this belief, which has only come about because most people do not understand the concept of homeostasis: many non-scientists instinctively see homeostasis as an activity that requires conscious control, although this is not so. This leads to some confusion on both sides, and the labels mysticism and scientism are applied to some adherents of the theory.

Semantic debate

The question of "what is an organism" and at what scale is it rational to speak about organisms vs. biospheres, give rise to a semantic debate. We are all ecologies in the sense that our (human) bodies contain gut bacteria, parasite species, etc., and to them our body is not organism but rather more of a microclimate or biome. Applying that thinking to whole planets:

The argument is that these symbiotic organisms, being unable to survive apart from each other and their climate and local conditions, form an organism in their own right, under a wider conception of the term organism than is conventionally used. It is a matter for often heated debate whether this is a valid usage of the term, but ultimately it appears to be a semantic dispute. In this sense of the word organism, it is argued under the theory that the entire biomass of the Earth is a single organism (as Johannes Kepler thought).

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