The Structure of Scientific Revolutions
Thomas Kuhn , 1962
(This is substantially a paper I wrote in 2006 for my MA program Historiography class.)

Thomas Kuhn applied the concept of the paradigm to describe the progress of scientific thought over time. The idea generated interest and discussion across a number of fields in addition to the history of science, eclipsing to some extent Kuhn’s original focus. This can be a danger when a new explanatory scheme becomes extremely popular: often it is extended by analogy beyond its actual usefulness. A notorious example of this effect was Social Darwinism, but other ideas such as the uncertainty principle, relativity, and memes have all been extended into areas where it's not entirely clear they are appropriate. Kuhn seems to have been aware of this potential problem, so he refined his description, made many of his assumptions explicit, and gave some suggestions and warnings regarding wider application in a Postscript included in the edition I read. Taken together, the text and Postscript present a structure and tool-set that if used carefully would be very helpful to the historian.

Kuhn’s thesis was that scientific progress does not proceed cumulatively, but rather oscillates between stable periods of what he called “normal science,” during which scientists elaborate and extend a single dominant paradigm, and revolutionary breaks when an existing paradigm is abandoned in favor of a new one.  Kuhn defined a paradigm as “the entire constellation of beliefs, values, techniques, and so on shared by members of a given community”. It is also an “exemplar,” a set of symbols, problems and solutions by which students learn the language and worldview of the discipline.

Kuhn denied that scientific development progresses by a series of “successive increments” that add to the accumulation of facts making up current knowledge like bricks building a wall. He portrayed professional scientific life not as an impartial empirical exploration, but as mostly  “mop-up work” to elaborate and extend whatever happens to be the existing paradigm. Kuhn provided several examples demonstrating that the normal scientist is “an expert puzzle-solver” rather than a creative innovator.  Sharing a paradigm allows a scientific community to take the foundations of their field for granted, resulting in highly refined answers to the most elaborately esoteric problems.

Periods of normal science are interrupted when anomalies between observations and the expectations suggested by the paradigm begin to demonstrate the paradigm’s weakness. Kuhn described the initial difficulty in seeing anomalies, caused by a conditioning of scientists’ perceptions by the paradigm. But as insecurity caused by the growing preponderance of anomalies increases, it leads to a crisis for the existing paradigm. An important element of this change is that the immediate reaction to a crisis of scientific anomalies is not abandonment of the paradigm. Kuhn provided examples of major and minor revolutions, showing that the strict falsifiability suggested in Karl Popper’s theory does not play a role. Kuhn claimed a paradigm is never released by scientists until a new one is accepted in its place. Revolutions are a scientific community’s rejection of an existing paradigm in favor of a new one. The adoption of the new paradigm changes scientists’ perceptions, tools, and language in a way that makes their understanding incommensurable with that of the old paradigm scientists. “Confronting the same constellation of objects as before and knowing that he does so, [the scientist] nevertheless finds them transformed”, said Kuhn.  These revolutions appear invisible in the history of science, Kuhn explained, because each successive generation learns science through the lens of the current paradigm.

In what might seem a Postmodern turn, Kuhn argued that scientific paradigm choices are ultimately made through a “conversion experience,” rather than through the agreement of a particular paradigm with observation of nature, because
nature cannot be seen except through a paradigm. The paradigm cannot be accepted incrementally, it must be experienced from within. “To translate a theory or worldview into one’s own language is not to make it one’s own. For that one must go native, discover that one is thinking and working in, not simply translating out of, a language that was previously foreign”.  This is necessarily both an all-or-nothing and a one-way process, Kuhn said.

History differs from science in that many interpretive traditions seem to peacefully coexist within their respective sub-disciplines. On the other hand, it could be argued that each particular historiographical tradition functions as a separate paradigm to a degree that merits exploration, even if less than in the absolute sense Kuhn has claimed for science. Historians may find themselves in a situation similar to the scientist’s paradigm crisis, if data refuses to make sense through any of their interpretive models. But the historians’ more acute awareness of the coexistence of other models may give them more flexibility than the scientist in their responses. Science must find for every effect a single cause. The historian is rarely faced with the same requirement.

Historians have the advantage of being able to live with explanatory ambiguity that would be unacceptable in science. And because they do not tend to go as deeply into esoteric specialization, historians may be less likely to develop the perceptual rigidity of scientists heavily invested in an existing paradigm. It would be interesting to investigate whether historians who DO rely on an esoteric specialist language, such as economic historians, might be more susceptible to being blinded by their paradigms? But generally, historians are always in contact with other paradigms. And since changes over time in interpretive traditions are actively studied by historians, the level of unselfconscious identification with a paradigm achieved by the scientist seems unlikely and inappropriate for the historian. But that doesn't mean we shouldn't try to be self-aware and guard against it!

Kuhn’s model accurately describes scientific revolutions because science relies on a single paradigm at a time, and its very detailed elaboration between crises. The existing paradigm always represents the best available fit with reality, without claiming to be the best possible fit. The process of normal science discovers anomalies, which accumulate to trigger crises resulting in new paradigms. Kuhn convincingly illustrates his thesis with examples of very large as well as very small revolutions, allowing us to see global changes as well as those restricted to a narrow sub-discipline. How accurately this model describes the discovery process in other fields could be judged by a similarly thorough analysis of their major and minor changes. Theoretically, it probably depends on the degree to which the field in question is structured around a series of successive paradigms accepted by all. Historians do not need a series of unanimously-held paradigms that preserve the problem-solving capabilities while changing the worldview of the predecessor. I think the most useful aspect of Kuhn’s book for understanding how historians work is not the theory of change, but the “exemplar” definition of the paradigm.

Exemplars are the concrete examples illustrating high-level concepts that a student learns when entering a field. Their mastery allows a discipline to know when the student has “assimilated a time-tested and group-licensed way of seeing”. Kuhn said exemplars allow us to “learn to see the same things when confronted by the same stimuli”. In this sense, paradigms function in any discipline to establish a degree of consensus about what Kuhn called “tacit knowledge.” Excessive attention to this tacit knowledge, especially if it's combined with deliberate avoidance of anything that doesn't conform, could be a way for paradigms to operate as deterrents to progress in historical thinking.