The Gaia Hypothesis is a theory proposed by British scientist James Lovelock in 1972. He believed that the entire planet is a self-regulating biosphere consisting of animate and inanimate parts. The complex web of relationships and feedback flows between its biota, rocks, oceans and atmosphere have created a stable environment fit for life that has lasted billions of years.
His friend, the novelist William Golding, suggested the name Gaia during one of their walks. In Greek mythology, Gaia was a primordial goddess who personified Earth. Lovelock preferred this "living" metaphor of the Earth to the more mechanical image of "spaceship Earth" that others often referred to.
Lovelock was worried that failure to understand the nature of the planet we live on would lead to the planet "cancelling us". He compared us to unruly teenagers who would be kicked out of Gaia's house if we didn't learn to behave. Or less euphemistically, the human species could go extinct under dramatically harsher conditions. The Gaia hypothesis is meant to deepen our understanding of the planet we live on, so that we can return to living harmoniously with it, as Indigenous cultures have done for thousands of years.
More recently, Lovelock's friend Stephen Harding has written a book called Gaia Alchemy, where he envisions a new science that incorporates the ancient wisdom of alchemy. Such a science would embrace intuition, feelings and sensations as ways in which Gaia communicates with us, and would restore balance to a culture that has been overly dominated by Cartesian rationalism.