In order to become a Social Democrat, a workingman must have a clear picture in his mind of the economic nature and the social and political features of the landlord, of the priest, of the high state official and of the peasant, of the student and of the tramp; he must know their strong and weak sides; he must understand all the catchwords and sophisms by which each class and each stratum camouflages its selfish strivings and its real 'nature'; he must understand what interests certain institutions and certain laws reflect and how they reflect them.