Social contract theory is the belief that societies exist through a mutual contract between individuals, and the state exists to serve the will of the people. The origins of social contract theory come from Plato's writings.
English philosopher Thomas Hobbes expanded on social contract theory, saying that people came together to create states to protect themselves from their naturally warlike tendencies. Hobbes believed that once the people created the state, they gave up any right to the state's power. Later, John Locke and John-Jacques Rousseau further interpreted the theory. Rousseau said that the government gets its authority from the consent of the people. Locke emphasized the role of the individual in society and believed that revolution was the people's obligation if the state abused its power.