Naturalists believe that the world is scientifically intelligible (at least in principle). Thus, naturalists doubt the reality of anything that cannot fit into a scientific worldview. How discomforting are naturalists’ doubts? Can naturalists coherently regard life as meaningful? Rosenberg is happily pessimistic about the answers to such questions. In this conversation, Rosenberg defends his pessimism, and Flanagan resists it. They discuss whether Darwin banished purpose (17:27), why naturalists get up in the morning (34:30), and morality and politics from a naturalist perspective (49:45), among other topics.