… is from page 453 of Deirdre McCloskey’s June 1976 article in the Journal of Economic Literature, “Does the Past Have Useful Economics? “:
Few intellectual activities are more mischievous when done poorly than economics or history. The power of fallacious economic reasoning or fallacious historical example to damage society is obvious: the pseudo-economics of mercantilism has been reducing trade and protecting vested interests for many centuries; the pseudo-history of the Aryan “race” lent dignity to German fascism. The combination of bad economics and bad history in bad economic history is pernicious.