The close interrelation between life and its environment, and its philosophical significance, was noted by the British chemist James E. Lovelock and the American biologist Lynn Margulis. They called this idea of complementary evolution of life and environment the Gaia hypothesis after Gaia, the ancient Greek goddess of the Earth. As Lovelock put it, this is "a new insight into the interactions between the living and the inorganic parts of the planet. From this has arisen the hypothesis, the model, in which the Earth's living matter, air, oceans, and land surface form a complex system which can be seen as a single organism and which has the capacity to keep our planet a fit place for life."
The Gaia hypothesis is highly controversial because it intimates that individual species (e.g., ancient anaerobic bacteria) might sacrifice themselves for the benefit of all living things. Furthermore, the hypothesis has yet to be formulated quantitatively and in a scientifically testable manner. However, regardless of the eventual validity of the idea that life controls its environment for its own benefit, the recognition that the Earth's physical, chemical, and biological components interact and mutually alter their collective destiny, by accident or design, is a profound insight.