Multiple Priorities in Evolving Scholarly Disciplines

In the history of science or a scholarly discipline, singleton discovery is the singular exception. As Robert K. Merton (sociologist, historian, and philosopher of science) has amply explicated and documented, multiples are the expected rule (Merton 1973). Alfred North Whitehead also put it well, asserting in effect that every great principle was not discovered first by the one who enunciated it—a reductio ad absurdum overshoot implying that everything known was already known before the Big Bang.

I heartily welcome the new comments by Claes-Henric Siven and by Daniele Besomi corrective of any notion that all who wrote on the accelerator-multiplier matter were successors to any one author—be it Harrod in 1936, or Cassel in 1918, or J. M. Clark in 1917, or Bickerdike, or Hawtrey, or Aftalion, or . . . We in economics can learn from the experiences of historians delving into the evolution of the natural sciences. Alongside of the usual triad of competitors for priority in stating the basic law of the conservation of energy—Joule or Mayer or Helmholtz—Tom Kuhn (1959) has nominated nine other worthies. And Kuhn's most important point does go beyond that: What each one of the twelve did enunciate is not quite the same thing as the other eleven had done.

Cassel's version of Harrod-Domar is definitely not isomorphic with their version(s). (Even Domar is not quite Harrod-Domar.) Cassel's model applies to a Say's-law world in which an insufficiency of “effective demand” is quite impossible. And Solow-Meade growth models of the mid–twentieth century are more Casselian than they are Harrodian. When you put the microscope on the 1903 “Carver Lever,” does it really involve the relationship between certain X variables as stocks and their time derivatives as dX /  dt flows? When Harrod in 1939 moved on to exponential growth trends beyond quasi-sinusoidal 1936 Harrod cycles, did he steal fire from Keynes's fine 1937 Eugenics Review lecture on the economic consequences of a declining population? Or, as will not seem implausible to those who knew the incestuous Oxbridge relationships of the 1930s, was it Harrod who exported fiery coals from Oxford to King's College?

In order not to prolong the discussion into domains of diminishing returns, let me conclude these brief remarks by affirming that nothing in this new stage of the discussions tempts me to qualify now any of the words I had composed in response to the useful original commentary of Heertje and Heemeijer.