The notion that God and the world are mutually interdependent is generally taken to be unique to twentieth-century process theology. Largely, process thinkers have focused on classical theists, rather than the mystics. My thesis, however, is that, centuries before process came along, there were Western mystical concepts stressing that God needed the universe in order to become conscious and complete. In support of my thesis, I will provide a synopsis of the doctrines of God as found in mystics such as Boehme, Dionysius, Eckhart, and then show how Whitehead's aesthetic provides a coherent philosophical psychology of ecstasy. Key words: aesthetic experience, causal efficacy, consequent nature of God, ecstasy, feeling, German Romanticism, p...