Abstract
Historian and methodologist of economics Mark Blaug has pointed out that the existence of operational variables might be a reason for economists to accept the Keynesian macroeconomic theory and to reject Thorstein Veblen’s theory, which does not include variables as such, as a mainstream. In order to examine Blaug’s suggested criterion for the success of an economic theory, we study Veblen’s illuminating but neglected book The Theory of Business Enterprise. Different definitions of the term ‘operational’ are developed according to various versions of operationalism of Percy Bridgman and Paul Samuelson. We find operational variables in Veblen’s business cycles and depression theory but not in his capital and production theory. We conclude that Blaug’s assertion cannot fully explain the emergence of successful theories in the history of economics.