used the term Gaia theory. Lovelock states that the initial formulation was based on observation, but still lacked a scientific explanation. The Gaia hypothesis has since been supported by a number of scientific experiments and provided a number of useful predictions. First Gaia conference In 1985, the first public symposium on the Gaia hypothesis, Is The Earth a Living Organism? was held at University of Massachusetts Amherst, August 1–6. The principal sponsor was the National Audubon Society. Speakers included James Lovelock, George Wald, Mary Catherine Bateson, Lewis Thomas, John Todd, Donald Michael, Christopher Bird, Thomas Berry, David Abram, Michael Cohen, and William Fields. Some 500 people attended. Second Gaia conference In 1988, climatologist Stephen Schneider organised a conference of the American Geophysical Union. The first Chapman Conference on Gaia, was held in San Diego, California on March 7, 1988. During the "philosophical foundations" session of the conference, David Abram spoke on the influence of metaphor in science, and of the Gaia hypothesis as offering a new and potentially game-changing metaphorics, while James Kirchner criticised the Gaia hypothesis for its imprecision. Kirchner claimed that Lovelock and Margulis had not presented one Gaia hypothesis, but four: CoEvolutionary Gaia: that life and the environment had evolved in a coupled way. Kirchner claimed that this was already accepted scientifically and was not new. Homeostatic Gaia: that life maintained the stability of the natural environment, and that this stability enabled life to continue to exist. Geophysical Gaia: that the Gaia hypothesis generated interest in geophysical cycles and therefore led to interesting new research in terrestrial geophysical dynamics. Optimising Gaia: that Gaia shaped the planet in a way that made it an optimal environment for life as a whole. Kirchner claimed that this was not testable and therefore was not scientific. Of Homeostatic Gaia, Kirchner recognised two alternatives. "Weak Gaia" asserted that life tends to make the environment stable for the flourishing of all life. "Strong Gaia" according to Kirchner, asserted that life tends to make the environment stable, to enable the flourishing of all life. Strong Gaia, Kirchner claimed, was untestable and therefore not scientific. Lovelock and other Gaia-supporting scientists, however, did attempt to disprove the claim that the hypothesis is not scientific because it is impossible to test it by controlled experiment. For example, against the charge that Gaia was teleological, Lovelock and Andrew Watson offered the Daisyworld Model (and its modifications, above) as