Der Einzige und sein Eigentum
Max Stirner was highly critical of Proudhon, and in his work, "The Ego and Its Own", made the same criticism of Proudhon's expression before Marx, asking, "Is the concept 'theft' at all possible unless one allows validity to the concept 'property'? How can one steal if property is not already extant? ... Accordingly property is not theft, but a theft becomes possible only through property."