Models and mecanisms in economics : attempt to clarify their relationships[Modèles et mécanismes en économie : essai de clarification de leurs relations]

The article is an attempt to clarify the relationship between economic models and mechanisms. The latter refer to causal processes and interactions. What role do they play in models? One must distinguish between models as non-linguistic constructs and models in the more usual sense of formal systems of definitions and mathematical relations. Models in the second sense are interpreted as purporting to characterise or describe in part models in the first sense. Thus the fact that there is no explicit reference to process-based mechanisms in many formal models does not mean that these mechanisms do not play an essential role in the non-linguistic models that these formal models describe in an incomplete way.