CAT 2021 Slot 3 VARC: Kuhn and Scientific Revolutions

When Thomas Kuhn published *The Structure of Scientific Revolutions* in 1962, the dominant picture of science was cumulative. Knowledge, on this view, grew the way a coral reef grows: each generation of investigators added its layer of verified fact to those beneath, and the history of science was essentially a record of errors discarded and truths retained. Kuhn, a physicist turned historian, found that this picture did not survive contact with the archives. When he read Aristotle's physics not as a clumsy anticipation of Newton but on its own terms, it stopped looking foolish; it looked like a coherent way of seeing the world that simply asked different questions.

From such encounters Kuhn drew his central distinction between 'normal science' and revolution. Most of the time, he argued, scientists are not trying to overturn anything. They work within a paradigm—a constellation of exemplary achievements, shared techniques and tacit assumptions that tells them which problems are worth solving and what a solution should look like. Normal science is puzzle-solving: the puzzles are hard, but the rules are not in question, and a failure to solve one reflects on the scientist rather than on the paradigm. Kuhn insisted that this conservatism is not a vice. Precisely because practitioners do not waste energy debating foundations, they can pursue esoteric problems with a depth that would otherwise be impossible.

Yet the same commitment that makes normal science productive also makes it blind. Anomalies—results that refuse to fit—are at first ignored, explained away, or shelved for later. Only when they accumulate, or when one of them resists the best efforts of the best practitioners, does the field enter a period of crisis in which the rules themselves become negotiable. Out of crisis a rival paradigm may emerge, and the transition to it, Kuhn claimed, is less like a logical deduction than a gestalt switch. The duck becomes a rabbit; the same data are seen differently.

It was this last claim that provoked the fiercest reaction. If competing paradigms define their problems and standards differently, they may be, in Kuhn's notorious word, 'incommensurable': there may be no neutral court of appeal, no algorithm of evidence, that can adjudicate between them. Critics charged that Kuhn had turned theory choice into mob psychology and reduced the progress of science to a change of fashion. Kuhn spent much of his later career protesting that he had been misread. He never denied that scientists give reasons; he denied only that those reasons compel assent in the way a proof does. Accuracy, consistency, scope, simplicity and fruitfulness all matter, but they can pull in different directions, and weighing them requires judgment that differs from one competent scientist to another.

The irony is that Kuhn's own book underwent the fate it described. It began as an anomaly in the philosophy of science, was resisted, and then became so thoroughly absorbed that 'paradigm shift' now appears in management seminars and advertising copy, stripped of almost all its original sense. A term designed to capture the rarity and difficulty of genuine conceptual change is now used to describe a new smartphone. Perhaps that, too, is a kind of normal science: the domestication of a revolutionary idea into a routine tool.