If I were asked to answer the following question: What is slavery? and I should answer in one word, It is murder!, my meaning would be understood at once. No extended argument would be required to show that the power to remove a man's mind, will, and personality, is the power of life and death, and that it makes a man a slave. It is murder. Why, then, to this other question: What is property? may I not likewise answer, It is robbery!, without the certainty of being misunderstood; the second proposition being no other than a transformation of the first?

— Pierre-Joseph Proudhon, What Is Property?

Pierre-Joseph Proudhon (15 January 1809 – 19 January 1865) was a French socialist, politician, philosopher, and economist who founded mutualist philosophy and is considered by many to be the "father of anarchism". He was the first person to declare himself an anarchist, using that term, 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 property". Some consider his mutualism to be part of individualist anarchism while others regard it to be part of social anarchism.