Franz Oppenheimer was a German Jewish sociologist and political economist, who published also in the area of the fundamental sociology of the state.

Liberal socialism is a political philosophy that incorporates liberal principles to socialism. This synthesis sees liberalism as the political theory that takes the inner freedom of the human spirit as a given and adopts liberty as the goal, means and rule of shared human life. Socialism is seen as the method to realize this recognition of liberty through political and economic autonomy and emancipation from the grip of pressing material necessity. Liberal socialism opposes abolishing certain components of capitalism and supports something approximating a mixed economy that includes both social ownership and private property in capital goods.