“The 'Manifesto' being our joint production, I consider myself bound to state that the fundamental proposition which forms its nucleus belongs to Marx. That proposition is: that in every historical epoch, the prevailing mode of economic production and exchange, and the social organization necessarily following from it, form the basis upon which is built up, and from which alone can be explained, the political and intellectual history of that epoch; that consequently the whole history of mankind (since the dissolution of primitive tribal society, holding land in common ownership) has been a history of class struggles, contests between exploiting and exploited, ruling and oppressed classes; that the history of these class struggles forms a series of evolution in which, nowadays, a stage has been reached where the exploited and the oppressed class—the proletariat—cannot attain its emancipation from the sway of the exploiting and ruling class—the bourgeoisie—without, at the same time, and once for all, emancipating society at large from all exploitation, oppression, class distinctions and class struggles. This proposition, which, in my opinion, is destined to do for history what Darwin's theory has done for biology, we, both of us, had been gradually approaching for some years before 1845.”