Philosopher and scuba diver Peter Godfrey-Smith speaks in-depth about his new book, Metazoa: Animal Minds and the Birth of Consciousness. Peter explains how conscious experience evolved from animals in the sea millions of years ago. He introduces us to some of the fascinating creatures he meets on his scuba dives; sponges, soft coral, banded shrimp, giant cuttlefish, and hermit crabs. Peter is a professor in the School of History and Philosophy of Science at The University of Sydney.