A long time ago, someone (Gil Skillman, I believe) argued on pen-l that the Sraffa system was simply a special case of the Arrow-Debreu general equilibrium model. Anybody interested in this issue will want to look at Dumenil & Levy THE ECONOMICS OF THE PROFIT RATE, ch. 4. It suggests that this "special case" theory is wrong. However, not being an expert on (or an advocate of) either system, I can't say that D & L are right or wrong. They also have a useful passage on formalism, abstract model-building: "It is true that a model is always based on simplifying assumptions, but the construction of the model has the advantage that it requires, at least, that assumptions be made explicit. The purpose of a model is not to 'prove' a theory or to provide it 'scientific' foundations, but rather to test its internal consistency, i.e., to detect obscurities or internal contradictions. In addition, models often reveal properties which were not obvious initially. "There is also no denying the fact that modeling is not neutral and, actually, was not neutral in the development of economic theory. A model is based on a specific set of mathmeatical tools, such as linear equations, or dynamic systems. Here, it is obvious that there is a feedback effect from mathematics on economic theory. For example, the development of the so-called 'method of equilibrium' [that dominates mainstream economics], paralleled the progress of mathematics, from linear equations to complex fixed-point theorems. It is also clear that the lack of interest in dynamics can be partially explained by the comparative difficulty and late maturity of the mathematical field of dynamic systems. [I would also mention the ideological attractiveness of equilibrium conceptions. -- JD] "Mathematics are also responsible for a kind of fetishism among economists, who may believe that the progress of economic analysis is a function of the sophistication of its models, [even though] the simultaneous consideration of various simple [non-sophisticated] models ... is often more telling than the construction of [such] complicated frameworks." (p. 83-4) I recommend this book. It is very lucid and deals with a lot of interesting economic issues. in pen-l solidarity, Jim Devine [EMAIL PROTECTED] [EMAIL PROTECTED] Econ. Dept., Loyola Marymount Univ. 7900 Loyola Blvd., Los Angeles, CA 90045-8410 USA 310/338-2948 (daytime, during workweek); FAX: 310/338-1950 "As far as the laws of mathematics refer to reality, they are not certain; as far as they are certain, they really do not refer to reality." -- Albert Einstein.
