" From the moment when the bourgeois demand for the abolition of class privileges was put forward, alongside it appeared the proletarian demand for the abolition of the classes themselves. [...] The proletarians took the bourgeoisie at its word: equality must not be merely apparent, must not apply merely to the sphere of the state, but must also be real, must also be extended to the social, economic sphere. [...] Any demand for equality which goes beyond that, of necessity passes into absurdity. "

― Friedrich Engels , Anti-Dühring: Herr Eugen Dühring's Revolution in Science