Astrobiologist and theoretical physicist Sara Imari Walker shares an intriguing new scientific theory that explains what life is and how it emerges. What is life? This is among the most difficult open problems in science, right up there with the nature of consciousness and the existence of matter. All the definitions we have fall short. None help us understand how life originates or the full range of possibilities for what life on other planets might look like. Walker proposes a new paradigm for understanding what physics encompasses and what we recognize as life.