Marshall, Schumpeter and evolution

As Stan Metcalfe is the leading exponent of combining Marshallian and Schumpeterian conceptions of the evolution of economic systems, it is appropriate to explore the similarities and differences between Marshall's and Schumpeter's work, and in doing so, to draw particularly on major Companions to each and a conference volume, which is explicitly focused on such comparisons, to all of which he has contributed. Economic systems generate and diffuse novelty through the creation and application of knowledge, which is inherently unpredictable but which emerges from diverse forms of organization. This process of selective co-ordination relies on quasi-decomposability - which implies partial equilibrium, and therefore entails multiple failure and sometimes major disruption, both of which should be represented in economic theory and should inform economic policy.