Models of Mechanisms: The Case of the Replicator Dynamics

Abstract

The general replicator dynamics (RD) is a formal equation that is used in biology to represent biological mechanisms and in the social sciences to represent social mechanisms. For either of these purposes, I show that substantial idealisations have to be made – idealisations that differ for the respective disciplines. These create a considerable idealisation gap between the biologically interpreted RD and the learning interpretations of the RD. I therefore argue that these interpretations represent different mechanisms, even though they are interpretations of the same formal RD equation. Furthermore, I argue that this idealisation gap between the biological and economic models is too wide for the respective mechanisms to share a common abstract causal structure that could be represented by the general RD model.