Analytic & pragmatist · 1922–1996
Thomas Kuhn
Physicist turned historian of science who coined “paradigm shift”
Science mostly proceeds as “normal science” within a shared paradigm; when anomalies accumulate, a revolution installs a new paradigm that cannot be judged simply by the standards of the old.
Life and thought
Thomas Kuhn (1922–1996) took a PhD in physics at Harvard, but while preparing a general-education course on the history of science he read Aristotle’s physics and realised that it was not bad science but a different, coherent way of seeing nature. He turned to history, taught at Berkeley, Princeton and MIT, and in 1962 published The Structure of Scientific Revolutions, one of the most cited books of the twentieth century.
Kuhn argued that most science is “normal science”: puzzle-solving within a paradigm, a shared set of exemplary achievements, methods and assumptions that tells scientists which problems matter. Anomalies are at first set aside; when they pile up, a crisis leads to a revolution, as from Ptolemy to Copernicus or from Newton to Einstein. Rival paradigms are partly “incommensurable”, so the change is not settled by logic and evidence alone. Popper and others objected that this made science irrational; Kuhn answered that scientists choose between theories by shared values such as accuracy, simplicity and fruitfulness. “Paradigm shift” entered everyday speech.