Abstract
In 1933, Ragnar Frisch introduced a distinction between microdynamics and macrodynamics. His claim that he proposed the first macrodynamic analysis and that microdynamic schemes were limited to single markets or individual behaviours influenced the subsequent development of economic models. But the division was above all between tools: maximisation at the individual level, and dynamic analysis at the aggregate level. What was at stake was the question of economic rationality and whether it could be extended to an aggregate system. This paper reconstructs the different research programs to give a new picture of the development of early mathematical models in economics. © 2022 Informa UK Limited, trading as Taylor & Francis Group.