Karl Grün in the context of Young Hegelian

Pierre-Joseph Proudhon (/ˈpruːdɒ̃/, also US: /pruːˈdoʊn/; French: [pjɛʁ ʒozɛf pʁudɔ̃]; 15 January 1809 – 19 January 1865) was a French anarchist, socialist, philosopher, and economist who founded mutualist philosophy and is considered by many to be the "father of anarchism". He was the first person to call himself an anarchist, and is widely regarded as one of anarchism's most influential theorists. Proudhon became a member of the French Parliament after the Revolution of 1848, whereafter he referred to himself as a federalist. Proudhon described the liberty he pursued as the synthesis of community and individualism. Some consider his mutualism to be part of individualist anarchism while others regard it to be part of social anarchism.

Proudhon, who was born in Besançon, was a printer who taught himself Latin in order to better print books in the language. His best-known assertion is that "property is theft!", contained in his first major work, What Is Property? Or, an Inquiry into the Principle of Right and Government (Qu'est-ce que la propriété? Recherche sur le principe du droit et du gouvernement), published in 1840. The book's publication attracted the attention of the French authorities. It also attracted the scrutiny of Karl Marx, who started a correspondence with its author. The two influenced each other and they met in Paris while Marx was exiled there. Their friendship finally ended when Marx responded to Proudhon's The System of Economic Contradictions, or The Philosophy of Poverty with the provocatively titled The Poverty of Philosophy. The dispute became one of the sources of the split between the anarchist and Marxist wings of the International Working Men's Association. Some such as Edmund Wilson have contended that Marx's attack on Proudhon had its origin in the latter's defense of Karl Grün, whom Marx bitterly disliked, but who had been preparing translations of Proudhon's work.