Jean-Jacques Rousseau is the noted philosopher who argued for the social contract theory. In his seminal work, "The Social Contract," published in 1762, Rousseau posits that legitimate political authority relies on a contract between the government and the governed. He emphasizes the importance of the general will and collective decision-making, where individuals come together to form a community. His ideas profoundly influenced the Enlightenment and subsequent democratic thought. Rousseau's theories challenge the notion of absolute power, advocating for freedom and equality, shaping modern political philosophy significantly.