Gaia Hypothesis - (n.)
"Gaia" is the name for the goddess of Earth in Greek mythology. The English words geology, geochemistry, geography all contain the same root referring to Earth. "Gaia" and "Gaia Hypothesis" are concepts introduced by the British engineer and science writer James Lovelock (born 1919). They represent the thought that the dynamic life support systems of Earth (including the ocean, air, soil and the flux of elements) act much like an organism and appear to be internally controlled. An analogous concept from the early history of economics was Adam Smith’s "Invisible Hand" that controls market dynamics. "Gaia" is the "Invisible Hand" of biogeochemistry. Lovelock suggests that life processes regulate the radiation balance of Earth to keep it habitable. Since Earth is indeed habitable, and since the carbon cycle has helped to keep it that way throughout Earth history despite any changes in the Sun's brightness, there can be little argument that the "Gaia hypothesis" cannot be falsified. Some critics have made much of the fact that this personified “Life” cannot be expected to do things for future life. Yet, somehow life processes did help to keep the system "in check" - if this were not so, humans would not be here. Nevertheless, just as the "Invisible Hand" does not prevent market crashes, thus also "Gaia" cannot prevent major setbacks to life on Earth, from outside disturbance or even from internal runaway processes. While not strictly a "hypothesis" in the scientific sense since it cannot be falsified, the "Gaia hypothesis" has great merit as an educational tool, regarding the concepts of biogeochemical cycling. Do biogeochemical processes indeed combine forces to favor life on Earth? Critics suggest that the processes of living organisms in the past were not necessarily favorable for the long-term survival of the then existing life. For example, the growth of oxygen in the atmosphere, through expanding photosynthesis, greatly diminished opportunities for anaerobic organisms. However, new life forms evolved that took advantage of the new situation (for example, highly mobile multicellular organisms, including humans). See also “Biogeochemistry” and the people glossary entries, “Vernadsky” and “Hutchinson.”