An open society provides its citizens with a mechanism for changing government; a closed society doesn't, forcing its citizens to rely on extra-legal revolution. Popper analyzes the open-closed society debate using three exemplars of closed-society advocacy: Plato, Hegel (and wow, does Popper hate on Hegel), and Marx. The main analytical viewpoints are historicist (backward-looking, utopian) motivations for closed societies and rational (forward-looking, empirical) motivations for open societies.