The chapter aims to show how many conceptual points of the classical-Keynesian analysis are essentially based on a suitable interaction between causal and interdependent relationships. Throughout the analysis, the terms ‘causality’ and ‘interdependence’ are interpreted following the interpretation given by Herbert Simon as analytical characteristics of the relations between the magnitudes involved in the theory, rather than a feature of economic reality. A meticulous work of revisiting the analytical formulations of some important foundations of both classical and Keynesian theories has been presented here to bring to the surface the sequential or the simultaneous nature of the determination of the main variables and the economic meaning attached to these analytical properties.

In 2005, Luigi Pasinetti was asked by his friend and colleague Pier Paolo Varri how he would like his seventy-fifth birthday to be celebrated. Pasinetti immediately replied: ‘let us discuss my new book!’. The book was, of course, Keynes and the Cambridge Keynesians, which was almost finished at that time. One of the most original and provocative parts was the ‘Postlude: Fighting for Independence’ of Book Two (The Cambridge School of Keynesian Economics), where he portrays what he considers the main features of the classical-Keynesian school, offering a list of nine theoretical and methodological characteristics, qualifying and unifying (to some extent, at least) the economists associated with it (Pasinetti, 2007, pp. 217–237). When, about a couple of years ago, John E. Woods (a student of Luigi Pasinetti at King’s College in the late 1960s) and Philip Good (economics editor of Cambridge University Press) launched the idea of a collection of essays discussing Pasinetti’s ‘nine characteristics’, we felt it certainly an appropriate, though a somewhat unconventional, way to celebrate Pasinetti’s career as an economist.