Communism aims to replace private property and profit-based economies with public ownership and communal control of major resources. There are two phases of communism according to Marx: 1) A transitional system where the working class controls government and economy but still pays people based on work. 2) A fully realized communist society without class divisions or government, where production and distribution are based on the principle "from each according to his ability, to each according to his needs." Marx argued that history progresses through stages of class struggle and revolution as technological changes alter economic conditions, and that capitalism's internal contradictions would lead to its overthrow and replacement with communism.