Jean-Jacques Rousseau was a key contributor to the development of liberalism and democracy in the 18th century. He advocated for the general will of the people over a small ruling class and articulated the concept of popular sovereignty, suggesting that political legitimacy comes from the consent of the people. His ideas influenced the French and American revolutions and helped shape modern democratic government. Rousseau also emphasized the importance of irrational aspects of human nature like emotion. His views on education promoted child-centered learning that nurtures natural abilities over structured schooling. Rousseau's autobiographical writing helped establish the modern genre of autobiography.