african socialism amsterdam anarchism antimilitarism arab socialism august bebel austromarxism basel belgian labour party berne international brussels buddhist socialism camille huysmans christian socialism clara zetkin class struggle communism copenhagen criticisms of socialism democratic socialism dictatorship of the proletariat eco-socialism egalitarianism emile vandervelde equality of outcome fourth international georgi plekhanov guild socialism history of socialism hugo haase impossibilism international marxist tendency international union of socialist youth international working union of socialist parties islamic socialism james connolly jewish left jules guesde karl kautsky karl liebknecht karl renner latin america libertarian socialism list of trotskyist internationals london madrid market socialism marxism paris pavel axelrod pieter jelles troelstra proletarian revolution revolutionary socialism robert grimm rosa luxemburg social anarchism social democracy socialism in one country socialist international socialist party of uruguay socialist economics socialist market economy socialist state stuttgart switzerland trade union types of socialism utilitarianism utopian socialism victor adler vladimir lenin wilhelm liebknecht world federation of democratic youth world war i world war ii zimmerwald conference