In the 1970s, microbiologist Lynn Margulis and atmospheric chemist James Lovelock developed the Gaia theory. Embracing the circular logic of life and engineering systems, the Gaia theory states that Earth is a self-regulating complex system in which life interacts with and eventually becomes its own environmentGaia describes a living Earth: a body in the form of a planet. For billions of years, life has created an environment conducive to its continuation, influencing the physical attributes of Earth on a planetary scale. An idea with precedents in natural science and philosophy for millenia, Gaia resonates with the ancient magico-religious understanding that all is one: as above, so below.Fusing science, mathematics, philosophy, ecology and speculation, Gaia and Philosophy challenges Western anthropocentrism to propose a symbiotic planet. In its striking philosophical conclusion, the revolutionary Gaia paradigm holds important implications not only for understanding life's past but for shaping its future.