Economic historians and economic theorists can make an interesting and socially valuable journey together, if they will. It would be an investigation into the sadly neglected area of economic change.
As anyone familiar with the history of economic thought will immediately recognize, practically all the economists of the nineteenth century and many of the twentieth have believed uncritically that all that is needed to explain a given historical development is to indicate conditioning or causal factors, such as an increase in population or the supply of capital. But this is sufficient only in the rarest of cases.