While the neoclassicists forced the introduction of mathematics into optimization considerations and prepared the ground for the formalization of economics, the “Austrian School” of notable economists propagated the advantages of the free market economy and a restraint of the state in economics. This was taken up again by the monetarist Milton Friedman, who was a radical advocate of the free, almost state-uninfluenced market economy. The most influential economist of the 20th century, the Englishman John Maynard Keynes, was primarily concerned with how to avoid future economic crises after the experienced global economic crisis. In his opinion, the lack of effective demand was the cause, which should be compensated by the state through additional, debt-financed expenditures. The ordoliberals in Germany, especially after the Second World War, tried to combine the best of two worlds: The state should only set the framework and otherwise let the economy develop freely. The successful model of the young Federal Republic of Germany, the “social market economy”, conceived by Müller-Armack and implemented by Ludwig Erhard, had been shaped by these ordoliberal considerations.