‘Defining peace’ explains why there is no single definition of peace and looks at theories about peace. A narrow version of peace would be basic but relatively insecure. A broader version produces a more complex state of peace which would be more sustainable. Using a multiple approach would result in an even more complex but more stable state. Each version tries to answer the same question: can peace be made by subjugating enemies, assimilating them by converting them into something resembling the dominant group, or by accepting and reconciling with their differences? There are several theoretical approaches to peace focusing on the constitution of the state, the role of international organizations, the philosophy of peace, and social peace movements.