There are various synonyms for the name Pierre Joseph Proudhon, who was a French philosopher and politician. Some of these synonyms include "the father of anarchism," "the father of mutualism," or simply "Proudhon." He is known for his famous quote, "property is theft," and his belief in the importance of a society based on mutual aid and solidarity. His works include "What is Property?" and "The Philosophy of Poverty." Despite his controversial views, Proudhon's ideas have influenced many anarchist and mutualist movements around the world.