Why Did Schumpeter Neglect Intellectual Property Rights?

Joseph Schumpeter is the father of evolutionary economics and the origin of notion that technical change is the key to capitalism as an engine of economic growth. His most famous book is Capitalism, Socialism and Democracy (1942) which develops the thesis that capitalism is always an evolutionary process of creative destruction. When this book was published fifty years ago, there was little solid scholarship on technical advance. Now there is a great deal, so much so that it would take a book to do justice to it. Nevertheless, Schumpeter s book correctly captures many of the stylised facts about technical progress revealed in recent research but, oddly enough, he never discussed, or even mentioned, intellectual property rights and this despite the fact that patent legislation was a prominent subject of debate in nineteenth century economics. This is a puzzle I hope to resolve in this paper