The disciplinary influence ofphysics, biology, and chemistryon economic modellingOverview and implications forunderstanding agricultural change

Economic research on structural change in agriculture has repeatedly induced controversies aboutbasic theoretical concepts, such as rational behaviour and equilibrium, and their analytical andpolitical implications. To contribute to the epistemological dimension of this debate, the article givesan overview of three paradigms to economic modelling whose proponents have been inspired byphysics, biology, and chemistry. The key concepts of general equilibrium theory, evolutionary economicsand the “social chemistry” of Jon Elster are presented and compared. While all keep the ideathat intentional individual action can explain aggregate outcomes that are nevertheless unintended,they differ in assumptions concerning preferences and the characteristics of coordination mechanisms.There is no consensus on what counts as a good scientific explanation. Similarly, views differ to whatextent a spontaneous order in the economy has desirable properties. The emerging theoreticalheterogeneity, I conclude, provides new opportunities for understanding agrarian change in contemporarysociety, of which a few are outlined....