United States Transport Advance and Externalities

What role the railroad played and how changes in transportstimulated American economic advance, while puzzling questions, are not beyond all conjecture. And such questions never lacked for conjecture. But recent studies have given a rigorous and brilliant cast to that inquiry, if not a totally novel one. An older tradition was shaped by the historian's desire to see economic change “as it was,†by his recognition that every happening was indispensable to the actual course of history. The newer focus, on history “as it was not,†reflects a belief that in economic affairs, as in those of the heart, desire will find its object—or a sufficiently close substitute. It i s difficult for the economist to view any historic innovation as revolutionary or to equate technological novelty with economic importance. It is an easy step to use comparative statics; to measure history “as it was not†; and thereby to define economic importance.