Robustness and Local Linearisation in Economic Models

This paper discusses the importance of nonlinear dynamics from a theoretical and an empirical point of view. It stresses the need for global as opposed to local analysis and develops the important concept of robustness. Using this concept, the paper argues that much modern macroeconomics can be dismissed on methodological grounds alone. The paper also deals with the empirics of hyperinflation and with the detection of chaos in financial markets.