This paper addresses the theoretical explanation of profit and interest within three different approaches: i) classical/Marxian; ii) marginalist; and iii) Arrow-Debreu. In the classical/Marxian approach, incomes from capital are understood as a surplus whose amount depends on the class conflict. In the marginalist theory, the rate of interest is the price firms pay to households for the use of a factor of production named ‘capital’. In the Arrow-Debreu equilibrium theory, interest rates and firm profit are still present, but, as we shall try to show, they can hardly be seen as income from capital.
Fratini, S.M. (2020). Incomes from capital in alternative economic theories. In Pasquale De Muro, Saverio Maria Fratini, Alessia Naccarato (a cura di), Economics, Policy and Law (pp. 89-109). Roma : Roma Tre Press.