Summary
Thomas Kuhn (1922–1996) was an American philosopher and historian of science whose 1962 book The Structure of Scientific Revolutions changed how people think about how science works. Before Kuhn, the standard story was cumulative: science progresses by steadily adding facts and refining theories. Kuhn argued instead that science alternates between long stretches of routine work within an accepted framework (what he called “normal science”) and brief, wrenching episodes of revolutionary change in which the framework itself is replaced. The vocabulary he introduced (paradigm, normal science, paradigm shift, incommensurability) entered general intellectual discourse far beyond philosophy of science, and his account has had direct consequences for how medicine understands its own epistemological foundations.
Life and Career
Kuhn trained in physics at Harvard, receiving his doctorate in 1949. His turn toward the history of science came through teaching, when he was asked to develop a science course for humanities undergraduates. The experience of trying to make Aristotelian physics intelligible to students who regarded it as obviously wrong produced the central insight of his career: that past scientific theories, studied in their own terms rather than measured against modern knowledge, appear not as errors but as coherent responses to the evidence available. Historians of science who study Aristotelian dynamics, phlogistic chemistry, or caloric thermodynamics, Kuhn observed, find them neither less scientific nor more idiosyncratic than current theories (Kuhn, 1962).
This observation led him to Alexandre Koyré’s new historiography, which sought to display the historical integrity of past science in its own time rather than to extract its permanent contributions to present knowledge (Kuhn, 1962). The result was Structure, published as a monograph in the International Encyclopedia of Unified Science and eventually translated into more than twenty languages. Kuhn went on to teach at Berkeley, Princeton, and MIT, and his work shaped the next two generations of philosophers, sociologists, and historians of science.
The Argument of Structure
Kuhn opens Structure with a complaint about scientific textbooks (Kuhn, 1962). By presenting a tidy, cumulative narrative, textbooks misrepresent how science actually develops (Kuhn, 1962). If science is taken to be the constellation of facts, theories, and methods in current texts, then development becomes a piecemeal accumulation (Kuhn, 1962). Kuhn’s claim, by contrast, is that the history of science shows tradition-shattering episodes (Copernicus, Newton, Lavoisier, Einstein), each of which required a community to reject one time-honored theory in favor of another that was incompatible with it (Kuhn, 1962). The assimilation of a new theory is not an increment to existing knowledge but a reconstruction of prior theory and a re-evaluation of prior fact (Kuhn, 1962). A discovery like that of oxygen or X-rays does not simply add an item to the scientist’s world; it requires shifting the network of theory through which that world is interpreted (Kuhn, 1962). And it is competition between segments of the scientific community, not solitary confrontation with the facts, that ever actually produces such replacements (Kuhn, 1962).
He also rejects, from the opening chapter, the philosopher’s image of method as a self-sufficient algorithm. Methodological directives alone cannot dictate a unique scientific conclusion; prior experience, accident, and individual makeup are always formative ingredients (Kuhn, 1962). And normal science suppresses fundamental novelties because they are subversive of its commitments; yet because the commitments retain an arbitrary element, novelty cannot be suppressed forever (Kuhn, 1962).
Normal Science and Paradigms
Kuhn defines normal science as research firmly based on past achievements that a scientific community acknowledges as supplying the foundation for further practice (Kuhn, 1962). Such achievements (what he called paradigms) are sufficiently unprecedented to attract adherents away from competing modes of inquiry and sufficiently open-ended to leave problems for practitioners to resolve (Kuhn, 1962). The classics he cites include Aristotle’s Physica, Ptolemy’s Almagest, Newton’s Principia and Opticks, Franklin’s Electricity, and Lavoisier’s Chemistry (Kuhn, 1962).
A paradigm gains its status by being more successful than competitors at solving a few acute problems; its initial success is a promise, not a completed program, and normal science consists in making good on that promise (Kuhn, 1962). The paradigm is not a grammatical pattern to be replicated; it is closer to a judicial decision in common law, an object for further articulation under new or more stringent conditions (Kuhn, 1962). The work that follows has three usual foci: refining facts the paradigm has marked as significant; comparing facts directly with predictions; and articulating the paradigm itself to settle residual ambiguities (Kuhn, 1962). Even apparently neutral empirical laws like Boyle’s gas law or Coulomb’s law of electrical attraction were not arrived at by pure induction; they emerged through paradigm articulation, with categories like “elastic fluid” already in place (Kuhn, 1962). Closely examined, normal science is an attempt to force nature into the preformed and relatively inflexible box that the paradigm supplies; phenomena that will not fit the box are often not seen at all (Kuhn, 1962). Those restrictions, born of confidence in a paradigm, are essential to scientific progress: they let scientists investigate a small range of relatively esoteric problems in a depth that would otherwise be unimaginable (Kuhn, 1962). Extraordinary problems, the kind that lead to new paradigms, are not had for the asking, but emerge only on occasions prepared by the advance of normal research (Kuhn, 1962).
Normal Science as Puzzle-Solving
Normal science problems, in Kuhn’s vocabulary, are puzzles: problems with assured solutions that constrain acceptable methods and answers through paradigm-derived rules (Kuhn, 1962). The motivation of the working scientist, on this account, is less the romantic search for novelty than the conviction that, with enough skill, one can solve a puzzle no one before has solved or solved as well (Kuhn, 1962). The price of this efficiency is real. A paradigm can insulate the community from socially important problems that cannot be reduced to puzzle form because the conceptual and instrumental tools the paradigm supplies cannot state them; Kuhn names seventeenth-century Baconianism and parts of contemporary social science as illustrations (Kuhn, 1962). He pointed in passing to a comparable risk for medicine: a cure for cancer or the design of a lasting peace are often not puzzles at all, because they may have no solution.
The rules constraining normal science fall into four kinds: explicit scientific laws and concepts; commitments to preferred instrumentation; quasi-metaphysical commitments such as corpuscularianism; and the broadest values that define what it means to be a scientist (Kuhn, 1962). After about 1630, the Cartesian corpuscular philosophy functioned as both a metaphysical and a methodological commitment, telling scientists what the universe contained, what ultimate laws must look like, and what research problems were worth pursuing (Kuhn, 1962). Yet (and this is where Kuhn parts company with the rule-bound picture of science), paradigms can guide research even in the absence of explicit rules. Rules derive from paradigms, but the paradigm is prior to and more complete than any extractable set of rules (Kuhn, 1962).
The Priority of Paradigms
Kuhn made a stronger claim still. Scientists can agree in their identification of a paradigm without agreeing on, or even attempting, a full interpretation or rationalization of it; lack of agreed rules does not prevent a paradigm from guiding research (Kuhn, 1962). He drew here on Wittgenstein’s notion of family resemblance: confronted with a previously unobserved activity, we apply the term “game” because what we see resembles a number of activities we have already learned to call by that name, not because every game shares a single set of necessary and sufficient conditions (Kuhn, 1962). Scientists never learn concepts, laws, and theories abstractly. They encounter them within the historically and pedagogically prior unit that displays them through their applications, so they need not be able to state explicit rules to do good work (Kuhn, 1962). Methodological debates surface mainly during pre-paradigm periods and during crises; the unconcern about rules vanishes whenever paradigms are felt to be insecure (Kuhn, 1962). And paradigms are not uniform across a discipline: a change in quantum mechanics may be revolutionary for solid-state physicists but not for nuclear chemists, since the same large theory functions as a different paradigm for different specialist communities (Kuhn, 1962). Kuhn explicitly aligns his account with Michael Polanyi’s notion of tacit knowledge (knowledge acquired through practice that cannot be articulated explicitly) as an explanation for how scientists use paradigms without being able to spell out the rules they follow (Kuhn, 1962).
Pre-Paradigm Periods
Before a paradigm is established, Kuhn argued, a field exists in a pre-paradigm state characterized by competing schools (Kuhn, 1962)(Kuhn, 1962). In the history of optics, no single accepted view of the nature of light existed before Newton; competing groups derived from Epicurean, Aristotelian, or Platonic theory each emphasized different phenomena and could not share a common body of belief (Kuhn, 1962). Early eighteenth-century electricity was similar: there were almost as many views about electricity as there were important experimenters, illustrating how fact-collection without a paradigm generates competing schools (Kuhn, 1962). Franklin’s electrical theory ended that interschool debate by accounting with near-equal facility for nearly all known electrical effects, which freed the next generation to undertake more precise, esoteric, consuming work (Kuhn, 1962). The acquisition of a paradigm, on this telling, transforms a group merely interested in nature into a profession or discipline, with specialized journals and societies arriving at the moment a community first accepts a single paradigm (Kuhn, 1962). Pliny’s encyclopedic writings and the Baconian natural histories of the seventeenth century show what fact-gathering without a paradigm produces: a morass of information juxtaposing revealing and irrelevant facts without the guidance to distinguish them (Kuhn, 1962). Once the paradigm arrives, scientists no longer write Franklin- or Darwin-style books for general audiences; they communicate in brief articles addressed to professional colleagues (Kuhn, 1962).
Anomaly and Discovery
Discovery, in Kuhn’s reconstruction, commences with the awareness of anomaly (recognition that nature has somehow violated paradigm-induced expectations), then continues with extended exploration of the anomalous area, and closes only when the paradigm has been adjusted so that what was anomalous becomes expected (Kuhn, 1962). The discovery of oxygen illustrates the pattern. At least three claimants, Scheele, Priestley, and Lavoisier, were involved, all working within or against the phlogiston theory, showing that discovery is an extended process of conceptual assimilation rather than a single act (Kuhn, 1962). Discovering a new sort of phenomenon requires both recognizing that something exists and understanding what it is; observation and conceptualization are inseparably linked, which is why discovery must take time (Kuhn, 1962). What Lavoisier announced in 1777, on Kuhn’s reading, was not the discovery of oxygen but the oxygen theory of combustion, the keystone for a reformulation of chemistry so vast it is still called the chemical revolution (Kuhn, 1962).
Röntgen’s X-rays show the same structure. The discovery began when he interrupted a study of cathode rays because a barium platinocyanide screen at some distance from his shielded apparatus glowed when the discharge was running; seven hectic weeks of investigation followed before he announced the result (Kuhn, 1962). The reception was not measured surprise but shock. Lord Kelvin at first pronounced X-rays an elaborate hoax, because, although they were not prohibited by established theory, they violated deeply entrenched expectations implicit in the design and interpretation of laboratory procedures (Kuhn, 1962). The Bruner-Postman anomalous-playing-card experiments make the same point in a controlled setting. Subjects shown a black four of hearts at brief exposures consistently identified it without hesitation as the four of either spades or hearts, fitting it without awareness of trouble to a category prepared by prior experience; only at longer exposures did the anomaly register, often with distress (Kuhn, 1962). Anomaly, then, appears only against the background a paradigm provides, and the more precise and far-reaching the paradigm, the more sensitive an indicator of anomaly it offers (Kuhn, 1962).
Crisis
All major scientific revolutions, Kuhn argued, were preceded by a period of pronounced professional insecurity generated by persistent failure of normal puzzle-solving (Kuhn, 1962). Ptolemaic astronomy was admirably successful for centuries, but as time went on its complexity increased far more rapidly than its accuracy; a discrepancy corrected in one place would show up in another. By the early sixteenth century the field was visibly in trouble, which is the precondition Copernicus needed (Kuhn, 1962). The chemical crisis preceding Lavoisier had two main components: the proliferation of pneumatic chemistry, which kept revealing gases the phlogiston theory could not accommodate, and the unexplained weight gain when metals are roasted. By the early 1770s there were nearly as many versions of the phlogiston theory as there were pneumatic chemists (Kuhn, 1962). Such proliferation of versions of a theory (many competing articulations, no two alike) is, on Kuhn’s account, a very usual symptom of crisis, and Copernicus had complained of the same thing in the preface to De Revolutionibus (Kuhn, 1962). The late-nineteenth-century crisis preceding Einstein arose from the incompatibility between Maxwell’s electromagnetic theory and Newtonian mechanics, especially the problems of motion with respect to the ether (Kuhn, 1962). Anticipations of new theories often existed before their crises but were ignored: Aristarchus’ heliocentric proposal was set aside for eighteen centuries because there was no crisis in geocentric astronomy at the time, and the geocentric system had no needs the heliocentric one might even conceivably have answered (Kuhn, 1962). As long as paradigm tools continue to solve the problems they define, science moves fastest through confident employment of those tools; crises indicate that retooling has become necessary (Kuhn, 1962).
Response to Crisis
Scientists do not renounce a paradigm merely because confronted with anomalies. A scientific theory is declared invalid only if an alternate candidate is available to take its place; no historical process Kuhn could find resembled the methodological stereotype of falsification by direct comparison with nature (Kuhn, 1962). The act of judgment that leads scientists to reject an accepted theory rests on more than a comparison of that theory with the world; the decision to reject one paradigm is always simultaneously the decision to accept another, and the comparison runs paradigm against paradigm and each against nature (Kuhn, 1962). To reject a paradigm without simultaneously substituting another is to reject science itself; there is no such thing as research in the absence of any paradigm (Kuhn, 1962). The same observation can be a puzzle in one period and a counterinstance in another: Copernicus saw as counterinstances what Ptolemy’s later successors had treated as puzzles, Lavoisier saw as a counterinstance what Priestley took to be a successfully solved puzzle, and Einstein saw as counterinstances what Lorentz and FitzGerald had handled as puzzles within the existing paradigm (Kuhn, 1962).
Crises, Kuhn observed, all begin with the blurring of a paradigm and the consequent loosening of the rules of normal research, and they close in one of three ways: normal science finally absorbs the problem; the problem is set aside as intractable for the moment; or a new candidate paradigm emerges and the contest begins (Kuhn, 1962). During acknowledged crises scientists turn to philosophical analysis as a device for unlocking the riddles of the field; the emergence of Newtonian physics in the seventeenth century and of relativity and quantum mechanics in the twentieth were each preceded and accompanied by fundamental philosophical analyses of the contemporary research tradition (Kuhn, 1962). And the people who actually invent new paradigms have almost always been very young or very new to the field, least committed by prior practice to rules that no longer define a playable game, most likely to conceive a different set (Kuhn, 1962).
Revolution and Incommensurability
Scientific revolutions, on Kuhn’s definition, are non-cumulative developmental episodes in which an older paradigm is replaced in whole or in part by an incompatible new one (Kuhn, 1962). He drew an explicit parallel with political revolutions. Both begin with a growing sense, often restricted to a segment of the relevant community, that existing institutions have ceased to function adequately. Both proceed through crisis. And both cannot be settled by appeals to existing institutions, since the institutions themselves are at issue (Kuhn, 1962). When paradigms enter a debate about paradigm choice, their role is necessarily circular: each group uses its own paradigm to argue in that paradigm’s defense, and the resulting circularity means the debate can only be settled by persuasion, not by a logically or probabilistically compelling demonstration for those who refuse to step into the circle (Kuhn, 1962).
The non-cumulative character of revolution is, on Kuhn’s reading, the rule rather than the exception. After the pre-paradigm period, the assimilation of new theories and of nearly all new sorts of phenomena has demanded the destruction of a prior paradigm and a consequent conflict between competing schools; cumulative acquisition of unanticipated novelties is an almost non-existent exception (Kuhn, 1962). New theories arise in response to a single class of phenomena: recognized anomalies whose stubborn refusal to be assimilated to existing paradigms forces theory construction. Phenomena already well explained by existing paradigms, and those whose details are merely awaiting articulation, do not generate new theories (Kuhn, 1962). Even theories later judged badly wrong did genuine work in their time; the much-maligned phlogiston theory gave order to a wide range of physical and chemical phenomena, and could have been saved from attack if its range of application had been restricted, but such restriction would have ended chemical research (Kuhn, 1962). For the Einsteinian revolution to succeed, Kuhn argued, Newton had to be wrong, not merely incomplete; the two theories make different predictions over the same domains, and that incompatibility is what makes the revolution genuine rather than additive (Kuhn, 1962).
Revolutions as Changes of World View
When paradigms change, the world itself changes with them. Led by a new paradigm, scientists adopt new instruments and look in new places, and during revolutions they see new and different things even when looking with familiar instruments in places they have looked before, as if the professional community had been suddenly transported to another planet (Kuhn, 1962). Something like a paradigm, Kuhn argued, is prerequisite to perception itself; what one sees depends both on what one looks at and on what one’s prior visual-conceptual experience has taught one to see (Kuhn, 1962). He gathered concrete cases. Uranus was seen on at least seventeen occasions between 1690 and 1781 by astronomers who could not see it as a planet because their paradigm provided no such category; only Herschel, with a better telescope and the openness to notice an anomalous disc-size, treated the observation as something other than a fixed star (Kuhn, 1962). Chinese astronomers, whose cosmology did not preclude celestial change, recorded sunspots and new stars centuries before Western astronomers could see them, because the Aristotelian paradigm of immutable heavens precluded the perception (Kuhn, 1962). Aristotelians who watched a swinging body saw constrained fall; Galileo, looking at the same swinging body, saw a pendulum, a body that almost succeeded in repeating the same motion endlessly, and built much of his new dynamics on the properties he could see and the others could not (Kuhn, 1962). Lavoisier saw oxygen where Priestley had seen dephlogisticated air and where others had seen nothing at all; learning to see oxygen also required learning to see a compound ore where Priestley and his contemporaries saw an elementary earth (Kuhn, 1962). The gestalt-switch comparison is suggestive but imperfect: scientists cannot toggle back and forth between paradigms the way a viewer can between duck and rabbit, and the period during which light was “sometimes a wave and sometimes a particle” was a period of crisis that ended only with wave mechanics and the realization that light was a self-consistent entity different from both (Kuhn, 1962).
The Invisibility of Revolutions
Kuhn devoted a chapter to the question of why scientists rarely notice revolutions; his answer was institutional: textbooks, being pedagogic vehicles for the perpetuation of normal science, systematically disguise both the role and the very existence of the revolutions that produced them (Kuhn, 1962). Scientific education encourages a mistaken sense of linear, cumulative development; the depreciation of historical fact is, Kuhn observed, deeply and probably functionally ingrained in the ideology of the scientific profession, the same profession that places the highest of values upon factual details of other sorts (Kuhn, 1962). Three different and incompatible versions of Dalton’s account of how he reached the atomic theory all made it appear a straightforward consequence of experiment; the mythology was so successful that Dalton himself may have come to believe it (Kuhn, 1962). Newton attributed to Galileo a result that Galileo never actually achieved and that violated Galileo’s own explicit laws; the textbook distortion arises because Galileo’s work is now read through Newtonian categories (Kuhn, 1962). Boyle’s “operational” definition of a chemical element, regularly cited in textbooks as the first clear modern formulation, was actually offered as part of an argument that there are no such things as chemical elements (Kuhn, 1962). Historians of science regularly encounter the difficulty of interpreting Boyle’s work in a way that is both chemically sound and consistent with his own writings — a symptom of how paradigm-driven expectations shape the reading of past science into an appearance of linear progression.(Kuhn, 1962) Textbooks do not preserve past science as it was; they rewrite history to fit the current paradigm, and scientists, unlike engineers, many doctors, and most theologians, do not consult original works (Kuhn, 1962)(Kuhn, 1962).
Resolution of Revolutions
The competition between paradigms, Kuhn maintained, is not the sort of battle that can be resolved by proofs. The transfer of allegiance from one paradigm to another is a conversion experience that cannot be forced and that proof cannot compel; lifelong resistance from those whose careers have committed them to the older tradition is not a violation of scientific standards but an index to the nature of scientific research itself (Kuhn, 1962). He cited Max Planck’s Scientific Autobiography for the most famous statement of the point: a new scientific truth does not triumph by convincing its opponents but by outliving them, by their dying off and a new generation growing up familiar with it (Kuhn, 1962). The same pattern applied to Copernicus. About sixty years after his death, when De Revolutionibus had been available for more than half a century, his proposal was still not generally accepted, and even those who accepted heliocentrism often regarded the theory as a computational device rather than as a description of physical reality (Kuhn, 1962). Paradigm debates cannot be reduced to logical arguments alone, because the participants use their own paradigms to evaluate the debate; the arguments are partially circular, and conversion depends on factors beyond logic: aesthetic considerations, promises of future success, professional judgment (Kuhn, 1962). Aesthetic considerations can be decisive: Kepler was originally converted to Copernicanism partly through Neoplatonic sun-mysticism, and such extra-scientific factors often tip the balance for early adopters (Kuhn, 1962). A new paradigm is often initially accepted on something like faith: its founders have to believe the paradigm can succeed despite the fact that it has not yet solved all the problems it faces, and early adopters must often embrace it in defiance of the evidence available within normal science (Kuhn, 1962). The proponents of competing paradigms practice their trades in different worlds: one contains constrained bodies that fall slowly, the other pendulums that repeat their motions; in one, solutions are compounds, in the other, mixtures; one is embedded in flat, the other in curved space (Kuhn, 1962). There is no neutral algorithm for theory-choice: the standard criteria (accuracy, scope, simplicity, fruitfulness) are real reasons, but they are not individually decisive or collectively sufficient to determine the decisions of individual scientists, and the scientific community exercises collective judgment by something more like an election than a proof (Kuhn, 1962).
Progress Without Teleology
Kuhn denied that scientific development approaches a truth about nature in the teleological sense. Drawing on a Darwinian analogy, he argued that evolution proceeds from a starting point, not toward a fixed goal, and that scientific development proceeds similarly: successive stages display an increasingly detailed and refined understanding of nature, but nothing in the account makes it a process of evolution toward anything in particular (Kuhn, 1962)(Kuhn, 1962). Science appears peculiarly progressive partly because the community making the progress judgments is the community being judged; progress is partly built into how the field defines itself (Kuhn, 1962). The insulation of a mature scientific community from lay demands and the elimination of competing schools through adoption of a single paradigm enables the extreme efficiency of puzzle-solving; this is one reason mature sciences progress faster than humanities or social sciences (Kuhn, 1962). After each revolution, textbooks present the new paradigm as the inevitable culmination of all previous work: the rupture is erased and the new paradigm appears the outcome of continuous accumulation (Kuhn, 1962). Scientific education, in keeping with this picture, is a process of narrow indoctrination. Students at all levels are not taught to read the primary literature or to evaluate conflicting interpretations but to apply standard techniques to standard problems (Kuhn, 1962). Post-revolutionary science is more esoteric, more narrowly focused, and less accessible to outsiders than pre-revolutionary science; specialization and isolation from the laity are not a disease but a feature of mature productive science (Kuhn, 1962).
The 1969 Postscript
The reception of Structure through the 1960s, including Margaret Masterman’s catalogue of twenty-one distinct senses in which Kuhn used the word “paradigm,” pushed him to write a substantial postscript for the 1969 second edition. He acknowledged that the term had been used in at least two fundamentally different senses: first, the entire constellation of beliefs, values, and techniques shared by a community; second, exemplary past achievements (concrete puzzle-solutions) that serve as models for normal science (Kuhn, 1962). For the sociological sense he proposed a new term, disciplinary matrix: “disciplinary” because it refers to the common possession of the practitioners of a particular discipline, “matrix” because it is composed of ordered elements (symbolic generalizations, models, values, exemplars) each requiring further specification (Kuhn, 1962). A scientific community, on his refined view, consists of practitioners of a scientific specialty who have undergone similar educations and professional initiations, absorbed the same technical literature, and drawn many of the same lessons from it; membership is determined by educational initiation and communication patterns, not subject matter alone (Kuhn, 1962).
He clarified, too, that a revolution need not be large. A paradigm shift for a community of fewer than twenty-five people constitutes a genuine revolution for that community even if no one outside notices; it is precisely because such small-scale change occurs so regularly that revolutionary, as against cumulative, change so badly needs to be understood (Kuhn, 1962). Exemplars (the concrete problem-solutions that students encounter from the start of their scientific education, on examinations, at the ends of textbook chapters) are, Kuhn now argued, the deepest and most philosophically important sense of “paradigm”; they enable scientists to recognize problems as similar and to apply solutions without consciously invoking rules (Kuhn, 1962). The knowledge embedded in shared examples is tacit knowledge, not subject without essential change to paraphrase in terms of explicit rules and criteria, yet systematic, time-tested, and corrigible, and not dismissable as merely subjective (Kuhn, 1962). Incommensurability, he proposed, should be understood as a translation problem between different language communities; proponents of competing paradigms speak different languages, and the difficulty of paradigm choice parallels the difficulty of translation across language communities, with the historian or sociologist learning to “speak the language” of an earlier scientific community in order to understand its accomplishments (Kuhn, 1962).
He pushed back against the relativist reading. Later scientific theories are better than earlier ones for solving puzzles in the often quite different environments to which they are applied; that is not a relativist’s position, and it preserves a real sense of scientific progress without any commitment to convergence on an external truth (Kuhn, 1962). He also noted that the shared values of a scientific community (accuracy, simplicity, consistency, plausibility, fruitfulness) may be applied differently by different members, and that this individual variability is not a weakness but a feature: it distributes risk and ensures the long-term health of the enterprise. If every member of a community responded to each anomaly as a source of crisis or embraced every new theory advanced by a colleague, science would cease (Kuhn, 1962).
Reception and Critique
Structure was published into a philosophy of science dominated by the logical empiricists and by Karl Popper’s falsificationism. The book’s argument (that paradigms are not falsified by counterinstances and that theory choice cannot be cast as a strict deductive argument) drew immediate fire. Popper’s followers, especially Imre Lakatos, argued that Kuhn’s account made science look irrational, a matter of “mob psychology” rather than reasoned judgment, and proposed in response his own methodology of scientific research programmes, intended to preserve a more rule-bound rationality while conceding Kuhn’s historical observations. Paul Feyerabend, who shared much of Kuhn’s empirical case, pushed in the opposite direction, treating the looseness of method as license for an explicit “anything goes.” Kuhn himself spent the rest of his career resisting the relativist reading, insisting that he was a “convinced believer in scientific progress” while denying that progress required convergence on a fixed external truth. His later technical work (on incommensurability as a problem of translation between language communities, and on the structure of taxonomic categories) extended the postscript’s framework but never produced a successor book of comparable reach.
The 1962 edition’s 50th-anniversary reissue and the continuing flood of secondary literature speak to the unusual durability of the original argument. Most working scientists encountered the book only in fragments, and the everyday use of “paradigm” and “paradigm shift” in non-scientific contexts is, by Kuhn’s own lights, almost always loose. Yet within philosophy and history of science, the basic vocabulary he provided (normal science, anomaly, crisis, paradigm choice, disciplinary matrix, incommensurability) remains the standard frame against which alternative accounts are still measured.
Medicine and Kuhn
Kuhn explicitly distinguished science from fields like medicine, technology, and law, noting that these have an external social need as their principal justification, unlike pure science (Kuhn, 1962). That distinction has not stopped his framework from being applied extensively to medicine. In the Oxford Handbook of the History of Medicine, Kuhn’s paradigm concept is discussed alongside Ludwik Fleck’s earlier concept of “thought collectives” and “thought styles,” which Kuhn acknowledged in Structure as an anticipation of his own work (Jackson (ed.), 2011). Fleck’s Genesis and Development of a Scientific Fact (1935), which traced the formation of the modern syphilis concept, used a strikingly similar vocabulary three decades before Kuhn. That Fleck has been recovered as a co-founder of the genre owes a great deal to Kuhn’s footnote in the introduction of Structure.
Kathryn Montgomery’s How Doctors Think discusses how clinical reasoning aims for causal simplicity, noting that the ethics of practice works to reduce cause in every case to the simplest manifestation possible (Montgomery, 2006). Jacob Stegenga’s Care and Cure argues that high rates of psychiatric comorbidity are an artifact of symptom-based nosology, leading to spurious comorbidity and overtreatment (Stegenga, 2018).
The relevance to medicine is structural rather than direct. Medicine does not undergo paradigm shifts in precisely Kuhn’s sense, because its relationship to theory differs from that of physics or chemistry, and Kuhn himself made the point. But the questions Kuhn raised (about how training shapes perception, how anomalies are handled or suppressed, how authority operates in knowledge communities, and how the textbook tradition conceals its own history) bear directly on medical epistemology and on the critique of evidence-based medicine’s claims to cumulative progress. Kuhn’s observation in chapter 11 that “unlike the engineer, and many doctors, and most theologians, the scientist need not and ordinarily does not consult the works of Newton or Dalton or Lavoisier” points toward something distinctive about medicine: medicine maintains a living dialogue with classical sources (Hippocrates, Galen, Sydenham, Osler) in a way that physics does not (Kuhn, 1962). That feature looks like a weakness if measured against Kuhn’s mature sciences, but it is also part of why medicine retains traditions of practice that would otherwise be lost.
See Also
- Epistemology
- Medical Epistemology
- Scientific Method
- Scientific Revolution
- Normal Science
- Philosophy of Medicine
- Ludwik Fleck
Sources
- Kuhn, T. S. (1962/1970). The Structure of Scientific Revolutions, 2nd ed. University of Chicago Press. [kuhn-scientificrevolutions-1962]; Lead authority
- Jackson, M., ed. (2011). The Oxford Handbook of the History of Medicine. Oxford University Press. [jackson-oxfordhandbook-2011]
- Montgomery, K. (2006). How Doctors Think: Clinical Judgment and the Practice of Medicine. Oxford University Press. [montgomery-how-doctors-think-2006]
- Stegenga, J. (2018). Care and Cure. University of Chicago Press. [stegenga-care-and-cure-2018]