The philosopher known for the concept of the social contract is Jean-Jacques Rousseau. He proposed that individuals enter into an implicit agreement to form a collective society, sacrificing some personal freedoms for the sake of communal security and mutual benefit. In his seminal work "The Social Contract," published in 1762, Rousseau argued that legitimate political authority relies on a social contract between the governed and the government. His ideas greatly influenced modern political thought, particularly in the contexts of democracy and human rights, fostering discussions on the nature of government and individual freedom.