Introduction

One of the most important events in macroeconomics in the last fifteen years has been the ascent of new classical macroeconomics. It has posed an interesting theoretical question, for one wonders how Keynesian theory, which was the core of macroeconomics, could have been supplanted by a theory which reaches diametrically opposite conclusions and advocates completely different policies. With the advancement of new classical macroeconomics, due especially to the work of R. Lucas, a new methodology which adopts a specific model for each problem was also established. There is now little hesitation about accepting a different model for the analysis of each phenomenon, so there are many apparently different models. Nevertheless there seem to be two features common to many of them. The first is the notion that in describing modern decentralised economies it is very useful to assume perfect competition. The second is the acceptance of an extreme form of positivism. On the basis of the Chicago-school models adopted over the past forty years, we can say that this positivism regards both the methodology adopted and the assumptions made as irrelevant as long as the theory fits the data or reproduces stylised facts of economic systems.