The philosopher known for his ideas on social contract theory is Jean-Jacques Rousseau. In his work, particularly "The Social Contract," published in 1762, Rousseau explored the relationship between individuals and the state. He argued that legitimate political authority derives from the consent of the governed, emphasizing that individuals relinquish certain freedoms for the protection of their rights and the common good. Rousseau's theories greatly influenced revolutionary thought, particularly during the French Revolution, by advocating for popular sovereignty and active citizenship. His ideas continue to be a cornerstone in political philosophy, shaping concepts of democracy and individual rights.