Thomas Kuhn

Thomas Kuhn: The Physicist Who Broke Progress

One slim book, published in 1962 inside an encyclopedia project run by the Vienna Circle's heirs, became the single most widely cited work in the social sciences and gave English a phrase now worn smooth by overuse: paradigm shift. Its author spent the following three decades explaining what he had not meant. Freeman Dyson recalled him saying, of the relativists who claimed him: "I am not a Kuhnian!"

Cincinnati, Manhattan, Croton

Thomas Samuel Kuhn was born on July 18, 1922 in Cincinnati, Ohio, to Samuel L. Kuhn, an industrial engineer, and Minette Stroock Kuhn; both parents were Jewish and non-observant. The family moved to Manhattan while he was an infant. His schooling was deliberately progressive: the Lincoln School through fifth grade, an institution that prized independent thinking over rote learning, then Hessian Hills School in Croton-on-Hudson for grades six through nine, where mathematics took hold. After a year at Solebury School he graduated from The Taft School in Watertown, Connecticut, in 1940. The pattern is worth noting — a decade of education designed to make a child suspicious of received answers, administered to a boy who would grow up to argue that science advances by periodically discarding them.

Physics at Harvard, and the Detour

Kuhn took his BSc in physics at Harvard in 1943, wrote for and then led the editorial board of *The Harvard Crimson*, and spent the war years on radar work at Harvard's Radio Research Laboratory, traveling to England, France and Germany. The MSc followed in 1946 and the PhD in 1949, with a dissertation on "The Cohesive Energy of Monovalent Metals as a Function of Their Atomic Quantum Defects" supervised by John Van Vleck. He was, on paper, a solid-state physicist.

What redirected him was a teaching assignment. At the suggestion of Harvard's president James B. Conant, Kuhn began teaching the history of science to non-scientists, and the encounter with how physics had actually been done — rather than how textbooks retrospectively tidied it — became his subject. He was a Harvard Junior Fellow from 1948 to 1951 and an assistant professor of general education and the history of science until 1957, when, with Conant's influence at the university waning, he was denied tenure.

Structure

Berkeley hired him in 1957 into both philosophy and history, naming him Professor of History of Science in 1961. There, in 1962, he published *The Structure of Scientific Revolutions*, which first appeared as an article in the *International Encyclopedia of Unified Science*.

The argument was that science does not accumulate. It moves through stages — prescience, with no governing paradigm; normal science, in which a community solves puzzles inside an accepted framework; and revolutionary science, in which the framework itself is replaced. Kuhn was careful to say that normal science is where the productivity is: "when the paradigm is successful, the profession will have solved problems that its members could scarcely have imagined and would never have undertaken without commitment to the paradigm." The paradigm is not a prison but a set of instructions for what counts as a question. It also determines what counts as data: "Operations and measurements that a scientist undertakes in the laboratory are not 'the given' of experience but rather 'collected with difficulty.'"

The explosive term was incommensurability — the claim that rival paradigms cannot be compared using a shared conceptual vocabulary, since the vocabulary itself shifts with the paradigm. Critics heard this as saying that theory choice is arbitrary and that Newton and Einstein were simply different fashions. Kuhn spent years denying it.

Five Values, Not Rules

His answer, developed in the essay "Objectivity, Value Judgment, and Theory Choice," was to name what scientists actually weigh: accuracy against experiment and observation, internal and external consistency, breadth of scope beyond the phenomena a theory was built for, simplicity, and fruitfulness in disclosing new phenomena. The crucial qualification was that these are not an algorithm. "The criteria of choice with which I began function not as rules, which determine choice, but as values, which influence it." Reasonable scientists holding the same five values can weight them differently and rationally disagree — which is not relativism, though it is not the tidy objectivity the positivists had promised either.

Princeton, MIT, and the Later Work

Kuhn directed the National Science Foundation's "Sources for the History of Quantum Physics" project from 1961 to 1964, interviewing Niels Bohr the day before Bohr died. He moved to Princeton in 1964 as M. Taylor Pyne Professor of Philosophy and History of Science, presided over the History of Science Society in 1969-70, and joined the Institute for Advanced Study from 1972 to 1979. In 1979 he went to MIT as Laurance S. Rockefeller Professor of Philosophy, serving as president of the Philosophy of Science Association in 1989-90 and taking emeritus status in 1991.

The later Kuhn largely abandoned paradigms for the semantic and taxonomic structure of scientific theories, arguing for a dynamic rather than static image of science, and reached for a new biological analogy: "The biological parallel to revolutionary change is not mutation, as I thought for many years, but speciation." Diagnosed with cancer of the bronchial tubes and throat in 1994, he was still working on *The Plurality of Worlds: An Evolutionary Theory of Scientific Development* when he died in Cambridge, Massachusetts on June 17, 1996, at seventy-three. It appeared in 2022.

Why Thomas Is Called a Genius

The quality on display in *Structure* is historical imagination applied to a discipline that had almost none: the ability to read past scientists as coherent rather than as failed versions of ourselves, and then to build a general theory of change out of that reading. It required being a working physicist — someone who knew what puzzle-solving felt like from inside — and simultaneously an outsider willing to describe that experience anthropologically. Very few people have occupied both positions. The results are measurable: *The Structure of Scientific Revolutions* is the most cited book in the social sciences, and Kuhn popularized "paradigm" from linguistics into ordinary English and coined "normal science."

The counter-case is real. Kuhn's central terms were notoriously slippery — "paradigm" was famously used in many senses — and incommensurability drew sustained fire from philosophers who argued it entailed irrationality; Karl Popper's falsificationism ran directly against Kuhn's distinction between normal and revolutionary science, producing one of the great quarrels of twentieth-century philosophy. Supporters of Michael Polanyi charged plagiarism, noting that Kuhn had attended Polanyi's lectures and debated epistemology with him before rising to prominence; the terminologies differ and the ideas appear to have been developed independently, and Kuhn acknowledged Polanyi in the second edition. He also declined to accept the position most often attributed to him. A thinker who repudiates his own most famous implication is either being misread or has not fully controlled his argument, and the record supports a bit of both.

Legacy

Kuhn held a Guggenheim Fellowship (1954) and was elected to the American Academy of Arts and Sciences (1963), the American Philosophical Society (1974) and the National Academy of Sciences (1979), winning the George Sarton Medal in 1982 and the John Desmond Bernal Award in 1983 and becoming a corresponding fellow of the British Academy in 1990. His framework reshaped post-positivist debate in international relations, the sociology of scientific knowledge, economics, political science and the humanities. The American Chemical Society named a prize after him — the Thomas Kuhn Paradigm Shift Award — for speakers who challenge mainstream scientific understanding, which is either a fitting tribute or exactly the routinization of revolution he described.