Kapp's main contribution was the development of a theory of social costs that captures urgent socio-ecological problems and proposes preventative policies based on the precautionary principle.
As such, Kapp's theory of social costs was an ongoing debate with neoclassical economics and the rise of neoliberalism.
In secondary school at the Hufengymnasium one of his teachers was the poet Ernst Wiechert[5] End 1920s he started studying law and economics at the universities in Berlin and Königsberg.
In Geneva Kapp had met the people of the Frankfurt School, who emigrated to the US and settled as Institute for Social Research at the Columbia University, New York City.
In that time he was also a visiting professor at the Ecole Pratique des Hautes Etudes, Sorbonne, Paris.