Perspectives on Science

In the fall of 1967 I entered Princeton as a Freshman intending to major in physics but interested as well in history. The catalog listed a course on the history of science, taught by a Professor Thomas Kuhn with the assistance of Michael Mahoney that seemed nicely to fit both interests. The course proved to be peculiarly intense for something about what was, after all, obsolete science as, each week, hundreds of pages of arcana from the distant past had to be absorbed. Professor Kuhn would pace back and forth in lecture, smoking intensely and talking rapidly to an elaborate outline drawn on the board at the beginning of each class. In tutorial, Mahoney (who passed away in 2009) developed Kuhn's points, forcing students to grapple with the meaning and significance of the many complicated texts that were assigned. That summer I worked as Mahoney's research assistant and, subsequently, as Kuhn's also.

Though the Structure of Scientific Revolutions was assigned in that class, Kuhn never put much explicit emphasis on it; he lectured almost entirely about the historical materials we were reading. Nevertheless it was clear that he had a guiding vision about science. Everything he spoke about, from Ptolemaic eccentrics to stationary orbits in the Bohr atom, seemed to exemplify a way of thinking about science that was certainly unusual for the time. It seemed that he was continually trying to excavate a structure beneath the dead science's apparent surface, something that could provide a key to understanding how it worked. He would often emphasize precisely what seemed to be the oddest, or the most irrelevant, passage or point in the reading. Kuhn never, or rarely, spoke explicitly about paradigms, normal science or incommensurability, but every story he told had things very much like those three elements at its core. Yet they took [End Page 279] their shape and meaning not through explicit definition but rather through the examples that he developed, and through the ways he answered questions.

During my time as Kuhn's research assistant we would meet every week or two to talk about old physics. He would always emphasize the need to uncover what kinds of characteristic problems were at issue in the past, and about how these problems connected to mathematical and theoretical structures, though not much at the time about experiments proper. In the spring of 1972, Kuhn taught a graduate seminar on the history of thermodynamics. The readings—all of them primary sources—had been carefully prepared and put on reserve. Each week one of the students was responsible for taking the class through the texts. Kuhn did not want a simple summary of relevant issues. He expected you to have figured out precisely what made the text tick. He already had pretty strong notions about the materials, and if you came up with something different from what he had in mind then you had to argue for it line by line, sometimes equation by equation (since most of the texts dealt with in that course were strongly mathematical).

Kuhn's most detailed effort to work through a body of past physics—his Black-body Theory and the Quantum Discontinuity—appeared in 1978. He had been hard at work on it since 1971. To those who knew him well over the years, the book itself very nicely exemplifies Kuhn's special approach to the history of science as well as his particular views about scientific development. Like most things that he wrote, Black-body Theory generated controversy, some directed at its apparent failure to apply what he had himself laid out in Structure, some directed at his specific, technical claims. It seemed to many of us who knew him that Kuhn was not bothered much or even at all by the former critique, but he was very much concerned with technical criticisms. His need, even compulsion, to find the—not a—core of meaning that unites a disparate series of texts, to extract that largely-implicit structure and to display how it governed and connected to a set of canonical problems, powerfully directed his historical research. Technical criticism accordingly...