John Locke was an English philosopher and physician born in 1632 who made significant contributions to Enlightenment thought. Some of his most notable works examined the social contract theory of government and the origins of human knowledge. He argued that people are born with a blank slate and form ideas based on experience. Locke also proposed people have natural rights to life, liberty, and property, and that governments should protect these rights with limited power. His Two Treatises of Government and An Essay Concerning Human Understanding were highly influential works during the Enlightenment period.