Thomas Kuhn Quotes

Ideas that require people to reorganize their picture of the world provoke hostility.

Normal science, the activity in which most scientists inevitably spend almost all their time, is predicated on the assumption that the scientific community knows what the world is like

Truth emerges more readily from error than from confusion.

The answers you get depend on the questions you ask.

And even when the apparatus exists, novelty ordinarily emerges only for the man who, knowing with precision what he should expect, is able to recognize that something has gone wrong.

Perhaps science does not develop by the accumulation of individual discoveries and inventions

Under normal conditions the research scientist is not an innovator but a solver of puzzles, and the puzzles upon which he concentrates are just those which he believes can be both stated and solved within the existing scientific tradition.

To reject one paradigm without simultaneously substituting another is to reject science itself.

What man sees depends both upon what he looks at and also upon what his previous visual-conception experience has taught him to see.

If these out-of date beliefs are to be called myths, then myths can be produced by the same sorts of methods and held for the same sorts of reasons that now lead to scientific knowledge

Newton's three laws of motion are less a product of novel experiments than of the attempt to reinterpret well-known observations in terms of motions and interactions of primary neutral corpuscles

Almost always the men who achieve these fundamental inventions of a new paradigm have been either very young or very new to the field whose paradigm they change.15 And perhaps that point need not have been made explicit, for obviously these are the men who, being little committed by prior practice to the traditional rules of normal science, are particularly likely to see that those rules no longer define a playable game and to conceive another set that can replace them.

Gravity, interpreted as an innate attraction between every pair of particles of matter, was an occult quality in the same sense as the scholastics' "tendency to fall" had been

Unanticipated novelty, the new discovery, can emerge only to the extent that his anticipations about nature and his instruments prove wrong.

Its assimilation requires the reconstruction of prior theory and re-evaluation of prior fact, an intrinsically revolutionary process that is seldom completed a single man and never overnight

Max Planck, surveying his own career in his Scientific Autobiography, sadly remarked that “a new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.

In science, as in the playing card experiment, novelty emerges only with difficulty, manifested by resistance, against a background provided by expectation.

When reading the works of an important thinker, look first for the apparent absurdities in the text and ask yourself how a sensible person could have written them.

The man who is striving to solve a problem defined by existing knowledge and technique is not, however, just looking around. He knows what he wants to achieve, and he designs his instruments and directs his thoughts accordingly. Unanticipated novelty, the new discovery, can emerge only to the extent that his anticipations about nature and his instruments prove wrong. . . . There is no other effective way in which discoveries might be generated.

though the world does not change with a change of paradigm, the scientist afterward works in a different world. Nevertheless,

As science historian Thomas Kuhn pointed out, scientific advances often come about when a new fact is discovered that can’t be explained.

Observation and experience can and must drastically restrict the range of admissible scientific belief, else there would be no science. But they cannot alone determine a particular body of such belief. An apparently arbitrary element, compounded of personal and historical accident, is always a formative ingredient of the beliefs espoused by a given scientific community at a given time

Because scientists are reasonable men, one or another argument will ultimately persuade many of them. But there is no single argument that can or should persuade them all. Rather than a single group conversion, what occurs is an increasing shift in the distribution of professional allegiances.

Unable either to practice science without the Principia or to make that work conform to the corpuscular standards of the seventeenth century, scientists gradually accepted the view that gravity was indeed innate

The competition between paradigms is not the sort of battle that can be resolved by proofs.

These three classes of problems-determinations of significant fact, matching facts with theory, and articulation of theory-exhaust, I think, the literature of normal science, both empirical and theoretical.

The term paradigm shift was introduced by Thomas Kuhn in his highly influential landmark book, The Structure of Scientific Revolutions. Kuhn shows how almost every significant breakthrough in the field of scientific endeavor is first a break with tradition, with old ways of thinking, with old paradigms.

once it has achieved the status of paradigm, a scientific theory is declared invalid only if an alternate candidate is available to take its place.

The combination of Bayes and Markov Chain Monte Carlo has been called "arguably the most powerful mechanism ever created for processing data and knowledge." Almost instantaneously MCMC and Gibbs sampling changed statisticians' entire method of attacking problems. In the words of Thomas Kuhn, it was a paradigm shift. MCMC solved real problems, used computer algorithms instead of theorems, and led statisticians and scientists into a worked where "exact" meant "simulated" and repetitive computer operations replaced mathematical equations. It was a quantum leap in statistics.

The depreciation of historical fact is deeply, and probably functionally, ingrained in the ideology of the scientific profession, the same profession that places the highest of all values upon factual details of other sorts.

The story of the Copernican Revolution never has been and probably never will be better told than in Thomas Kuhn's The Copernican Revolution: Planetary Astronomy in the Development of Western Thought (New York: MJF Books, 1985)

For reasons that are both obvious and highly functional, science textbooks (and too many of the older histories of science) refer only to that part of the work of past scientists that can easily be viewed as contributions to the statement and solution of the texts' paradigm problems. Partly by selection and partly by distortion, the scientists of early ages are implicitly represented as having worked upon the same set of fixed problems and in accordance with the same set of fixed canons that the most recent revolution in scientific theory and method has made seem scientific.

As writer and media strategist Ryan Holiday has noted, epiphanies are not life-altering.9 It’s not radical moments of action that give us long-lasting, permeating change—it’s the restructuring of our habits. The idea is what science philosopher Thomas Kuhn dubbed a “paradigm shift.” Kuhn suggested we don’t change our lives in flashes of brilliance, but through a slow process in which assumptions unravel and require new explanations. It’s in these periods of flux that microshifts happen and breakthrough-level change begins to take shape.

Despite all their surface diversity, most jokes and funny incidents have the following logical structure: Typically you lead the listener along a garden path of expectation, slowly building up tension. At the very end, you introduce an unexpected twist that entails a complete reinterpretation of all the preceding data, and moreover, it's critical that the new interpretation, though wholly unexpected, makes as much "sense" of the entire set of facts as did the originally "expected" interpretation. In this regard, jokes have much in common with scientific creativity, with what Thomas Kuhn calls a "paradigm shift" in response to a single "anomaly." (It's probably not coincidence that many of the most creative scientists have a great sense of humor.) Of course, the anomaly in the joke is the traditional punch line and the joke is "funny" only if the listener gets the punch line by seeing in a flash of insight how a completely new interpretation of the same set of facts can incorporate the anomalous ending. The longer and more tortuous the garden path of expectation, the "funnier" the punch line when finally delivered.

Thomas Kuhn’s book The Structure of Scientific Revolutions has probably been more widely read—and more widely misinterpreted—than any other book in the recent philosophy of science. The broad circulation of his views has generated a popular caricature of Kuhn’s position. According to this popular caricature, scientists working in a field belong to a club. All club members are required to agree on main points of doctrine. Indeed, the price of admission is several years of graduate education, during which the chief dogmas are inculcated. The views of outsiders are ignored. Now I want to emphasize that this is a hopeless caricature, both of the practice of scientists and of Kuhn’s analysis of the practice. Nevertheless, the caricature has become commonly accepted as a faithful representation, thereby lending support to the Creationists’ claims that their views are arrogantly disregarded.

Wolfgang Pauli, in the months before Heisenberg's paper on matrix mechanics pointed the way to a new quantum theory, wrote to a friend, "At the moment physics is again terribly confused. In any case, it is too difficult for me, and I wish I had been a movie comedian or something of the sort and had never heard of physics." That testimony is particularly impressive if contrasted with Pauli's words less than five months later: "Heisenberg's type of mechanics has again given me hope and joy in life. To be sure it does not supply the solution to the riddle, but I believe it is again possible to march forward.

The man who succeeds proves himself an expert puzzle-solver, and the challenge of the puzzle is an important part of what usually drives him on.

progress in science is not a simple line leading to the truth. It is more progress away from less adequate conceptions of, and interactions with, the world (§XIII). Let

....the power of a science seems quite generally to increase with the number of symbolic generalizations its practitioners have at their disposal.

Autobiographical Interview, ed. James Conant and

Discovery commences with the awareness of anomaly, i.e. with the recognition that nature has somehow violated the paradigm-induced expectations that govern normal science. It then continues with a more or less extended exploration of the area of anomaly. And it closes only when the paradigm theory has been adjusted so that the anomalous has become the expected.

Once a first paradigm through which to view nature has been found, there is no such thing as research in the absence of any paradigm. To reject one paradigm without simultaneously substituting another is to reject science itself. That act reflects not on the paradigm but on the man. Inevitably he will be seen by his colleagues as “the carpenter who blames his tools.” The

Inevitably those remarks will suggest that the member of a mature scientific community is, like the typical character of Orwell’s 1984, the victim of a history rewritten by the powers that be.

Why should a change of paradigm be called a revolution? In the face of the vast and essential differences between political and scientific development, what parallelism can justify the metaphor that finds revolutions in both? One aspect of the parallelism must already be apparent. Political revolutions are inaugurated by a growing sense, often restricted to a segment of the political community, that existing institutions have ceased adequately to meet the problems posed by an environment that they have in part created. In much the same way, scientific revolutions are inaugurated by a growing sense, again often restricted to a narrow subdivision of the scientific community, that an existing paradigm has ceased to function adequately in the exploration of an aspect of nature to which that paradigm itself had previously led the way. In both political and scientific development the sense of malfunction that can lead to crisis is prerequisite to revolution.

No language thus restricted to reporting a world fully known in advance can produce mere neutral and objective reports on "the given." Philosophical investigation has not yet provided even a hint of what a language able to do that would be like.

So how do you change paradigms? Thomas Kuhn, who wrote the seminal book about the great paradigm shifts of science, has a lot to say about that.8 You keep pointing at the anomalies and failures in the old paradigm. You keep speaking and acting, loudly and with assurance, from the new one. You insert people with the new paradigm in places of public visibility and power. You don’t waste time with reactionaries; rather, you work with active change agents and with the vast middle ground of people who are open-minded.

Of all the major developments in the history of science, there may be no better example than that of the periodic system to argue against Thomas Kuhn’s thesis that scientific progress occurs through a series of sharp revolutionary stages.20 Indeed, Kuhn’s insistence on the centrality of revolutions in the development of science and his efforts to single out revolutionary contributors has probably unwittingly contributed to the retention of a Whiggish history of science, whereby only the heroes count while blind alleys and failed attempts are written out of the story.21

Here is Thomas Kuhn, the philosopher of science, describing the way scientists react when their pet theories are unraveling: “What scientists never do when confronted by even severe and prolonged anomalies,” Kuhn wrote, “…. [is] renounce the paradigm that led them into crisis.” Instead, he concluded, “A scientific theory is declared invalid only if an alternate candidate is available to take its place.” That is, scientific theories very seldom collapse under the weight of their own inadequacy. They topple only when a new and seemingly better belief turns up to replace it.

Science does not deal in all possible laboratory manipulations. Instead, it selects those relevant to the juxtaposition of a paradigm with the immediate experience that that paradigm has partially determined. As a result, scientists with different paradigms engage in different concrete laboratory manipulations.

When it repudiates a past paradigm, a scientific community simultaneously renounces, as a fit subject for professional scrutiny, most of the books and articles in which that paradigm had been embodied. Scientific education makes use of no equivalent for the art museum or the library of classics, and the result is a sometimes drastic distortion in the scientist's perception of his discipline's past. More than the practitioners of other creative fields, he comes to see it as leading in a straight line to the discipline's present vantage. In short, he comes to see it as progress. No alternative is available to him while he remains in the field.

Thomas Kuhn explicó que la transmisión del paradigma es dogmática: el aprendiz de una disciplina científica adquiere un conjunto de supuestos y reglas para su trabajo intelectual y procede inmediatamente a aplicarlos a problemas nuevos, identificados por el paradigma como propiamente ‘gramáticos.’ Si cierto tipo de preguntas son legisladas como ‘no gramáticas’ por constituir retos a los supuestos o por quedar presuntamente fuera del campo de investigación disciplinario, el aprendiz lo absorbe de forma pasiva, confiando en sus tutores, y sin dar mayor problema. Además, hay toda una estructura de incentivos institucionales que fortalecen la docilidad, pues el aprendiz desea prestigiarse y avanzar, y eso requiere dar gusto a quienes lo entrenan.

Observation and experience can and must drastically restrict the range of admissible scientific belief, else there would be no science. But they cannot alone determine a particular body of such belief. An apparently arbitrary element, compounded of personal and historical accident, is always a formative ingredient of the beliefs espoused by a given scientific community at a given time.

Normal science, the activity in which most scientists inevitably spend almost all their time, is predicated on the assumption that the scientific community knows what the world is like... [It] often suppresses fundamental novelties because they are necessarily subversive of its basic commitments. Nevertheless, so long as those commitments retain an element of the arbitrary, the very nature of normal research ensures that the novelty shall not be suppressed for very long... [N]ormal science repeatedly goes astray. And when it does—when, that is, the profession can no longer evade anomalies that subvert the existing tradition of scientific practice—then begin the extraordinary investigations that lead the profession at last to a new set of commitments, a new basis for the practice of science. The extraordinary episodes in which that shift of professional commitments occurs are the ones known in this essay as scientific revolutions. They are the tradition-shattering complements to the tradition-bound activity of normal science.

It is, I think, particularly in periods of acknowledged crisis that scientists have turned to philosophical analysis as a device for unlocking the riddles of their field. Scientists have not generally needed or wanted to be philosophers. Indeed, normal science usually holds creative philosophy at arm's length, and probably for good reason. To the extent that normal research work can be conducted by using the paradigm as a model, rules and assumptions need not be made explicit. The full set of rules sought by philosophical analysis need not even exist.

Paradigms are not corrigible by normal science at all. Instead, as we have already seen, normal science ultimately leads only to the recognition of anomalies and to crises. And these are terminated, not by deliberation and interpretation, but by a relatively sudden and unstructured event like the gestalt switch. Scientists then often speak of the "scales falling from the eyes" or of the "lightning flash" that "inundates" a previously obscure puzzle, enabling its components to be seen in a new way that for the first time permits its solution. On other occasions the relevant information comes in sleep. No ordinary sense of the term 'interpretation' fits these flashes of intuition through which a new paradigm is born. Though such intuitions depend upon the experience, both anomalous and congruent, gained with the old paradigm, they are not logically or piecemeal linked to particular items of that experience as an interpretation would be. Instead, they gather up large portions of that experience and transform them to the rather different bundle of experience that will thereafter be linked piecemeal to the new paradigm but not to the old.

The question I hoped to answer,was how much mechanics Aristotle had known, how much he had left for people such as Galileo and Newton to discover. Given that formulation, I rapidly discovered that Aristotle had known almost no mechanics at all... that conclusion was standard and it might in principle have been right. But I found it bothersome because, as I was reading him, Aristotle appeared not only ignorant of mechanics, but a dreadfully bad physical scientist as well. About motion, in particular, his writings seemed to me full of egregious errors, both of logic and of observation.

Through the theories they embody, paradigms prove to be constitutive of the research activity. They are also, however, constitutive of science in other respects, and that is now the point. In particular, our most recent examples show that paradigms provide scientists not only with a map but also with some of the directions essential for map-making. In learning a paradigm the scientist acquires theory, methods, and standards together, usually in an inextricable mixture. Therefore, when paradigms change, there are usually significant shifts in the criteria determining the legitimacy both of problems and of proposed solutions.

Textbooks, however, being pedagogic vehicles for the perpetuation of normal science, have to be rewritten in whole or in part whenever the language, problem-structure, or standards of normal science change. In short, they have to be rewritten in the aftermath of each scientific revolution, and, once rewritten, they inevitably disguise not only the role but the very existence of the revolutions that produced them. Unless he has personally experienced a revolution in his own lifetime, the historical sense either of the working scientist or of the lay reader of textbook literature extends only to the outcome of the most recent revolutions in the field. Textbooks

No wonder, then, that in the early stages of the development of any science different men confronting the same range of phenomena, but not usually all the same range of phenomena, describe and interpret them in different ways. What is surprising, and perhaps also unique in its degree to the fields we call science, is that such initial divergences should ever largely disappear. For they do disappear to a very considerable extent and then apparently once and for all. Furthermore, their disappearance is usually caused by the triumph of one of the pre-paradigm schools, which, because of its own characteristic beliefs and preconceptions, emphasized only some special part of the two sizable and inchoate pool of information,

The scientific enterprise as a whole does from time to time prove useful, open up new territory, display order, and test long-accepted belief. Nevertheless, the individual engaged on a normal research problem is almost never doing any one of these things. Once engaged, his motivation is of a rather different sort. What then challenges him is the conviction that, if only he is skillful enough, he will succeed in solving a puzzle that no one before has solved or solved so well. Many of the greatest scientific minds have devoted all of their professional attention to demanding puzzles of this sort. On most occasions any particular field of specialization offers nothing else to do, a fact that makes it no less fascinating to the proper sort of addict.

Changing what we think is always a sticky process, especially when it comes to religion. When new information becomes available, we cringe under an orthodox mindset, particularly when we challenge ideas and beliefs that have been “set in stone” for decades. Thomas Kuhn coined the term paradigm shift to represent this often-painful transition to a new way of thinking in science. He argued that “normal science” represented a consensus of thought among scientists when certain precepts were taken as truths during a given period. He believed that when new information emerges, old ideas clash with new ones, causing a crisis. Once the basic truths are challenged, the crisis ends in either revolution (where the information provides new understanding) or dismissal (where the information is rejected as unsound). The information age that we live in today has likely surprised all of us as members of the LDS Church at one time or another as we encounter new ideas that revise or even contradict our previous understanding of various aspects of Church history and teachings. This experience is similar to that of the Copernican Revolution, which Kuhn uses as one of his primary examples to illustrate how a paradigm shift works. Using similar instruments and comparable celestial data as those before them, Copernicus and others revolutionized the heavens by describing the earth as orbiting the sun (heliocentric) rather than the sun as orbiting the earth (geocentric). Because the geocentric model was so ingrained in the popular (and scientific!) understanding, the new, heliocentric idea was almost impossible to grasp. Paradigm shifts also occur in religion and particularly within Mormonism. One major difference between Kuhn’s theory of paradigm shift and the changes that occur within Mormonism lies in the fact that Mormonism privileges personal revelation, which is something that cannot be institutionally implemented or decreed (unlike a scientific law). Regular members have varying degrees of religious experience, knowledge, and understanding dependent upon many factors (but, importantly, not “faithfulness” or “worthiness,” or so forth). When members are faced with new information, the experience of processing that information may occur only privately. As such, different members can have distinct experiences with and reactions to the new information they receive. This short preface uses the example of seer stones to examine the idea of how new information enters into the lives of average Mormons. We have all seen or know of friends or family who experience a crisis of faith upon learning new information about the Church, its members, and our history. Perhaps there are those reading who have undergone this difficult and unsettling experience. Anyone who has felt overwhelmed at the continual emergence of new information understands the gravity of these massive paradigm shifts and the potentially significant impact they can have on our lives. By looking at just one example, this preface will provide a helpful way to think about new information and how to deal with it when it arrives.

Philosophers of science have repeatedly demonstrated that more than one theoretical construction can always be placed upon a given collection of data. History of science indicates that, particularly in the early developmental stages of a new paradigm, it is not even very difficult to invent such alternates. But that invention of alternates is just what scientists seldom undertake except during the pre-paradigm stage of their science's development and at very special occasions during its subsequent evolution. So long as the tools a paradigm supplies continue to prove capable of solving the problems it defines, science moves fastest and penetrates most deeply through confident employment of those tools. The reason is clear. As in manufacture so in science-retooling is an extravagance to be reserved for the occasion that demands it. The significance of crises is the indication they provide that an occasion for retooling has arrived.

In recent years, however, a few historians of science have been finding it more and more difficult to fulfill the functions that the concept of development-by-accumulation assigns to them. As chroniclers of an incremental process, they discover that additional research makes it harder, not easier, to answer questions like: When was oxygen discovered? Who first conceived of energy conservation? Increasingly, a few of them suspect that these are simply the wrong sorts of questions to ask. Perhaps science does not develop by the accumulation of individual discoveries and inventions. Simultaneously, these same historians confront growing difficulties in distinguishing the “scientific” component of past observation and belief from what their predecessors had readily labeled “error” and “superstition.” The more carefully they study, say, Aristotelian dynamics, phlogistic chemistry, or caloric thermodynamics, the more certain they feel that those once current views of nature were, as a whole, neither less scientific nor more that product of human idiosyncrasy than those current today.

Every elementary chemistry text must discuss the concept of a chemical element. Almost always, when that notion is introduced, its origin is attributed to the seventeenth-century chemist, Robert Boyle, in whose Sceptical Chymist the attentive reader will find a definition of ‘element’ quite close to that in use today. Reference to Boyle’s contribution helps to make the neophyte aware that chemistry did not begin with the sulfa drugs; in addition, it tells him that one of the scientist’s traditional tasks is to invent concepts of this sort. As a part of the pedagogic arsenal that makes a man a scientist, the attribution is immensely successful. Nevertheless, it illustrates once more the pattern of historical mistakes that misleads both students and laymen about the nature of the scientific enterprise. According to Boyle, who was quite right, his “definition” of an element was no more than a paraphrase of a traditional chemical concept; Boyle offered it only in order to argue that no such thing as a chemical element exists; as history, the textbook version of Boyle’s contribution is quite mistaken.3

We noted in Section II that an increasing reliance on textbooks or their equivalent was an invariable concomitant of the emergence of a first paradigm in any field of science. The concluding section of this essay will argue that the domination of a mature science by such texts significantly differentiates its developmental pattern from that of other fields. For the moment let us simply take it for granted that, to an extent unprecedented in other fields, both the layman’s and the practitioner’s knowledge of science is based on textbooks and a few other types of literature derived from them. Textbooks, however, being pedagogic vehicles for the perpetuation of normal science, have to be rewritten in whole or in part whenever the language, problem-structure, or standards of normal science change. In short, they have to be rewritten in the aftermath of each scientific revolution, and, once rewritten, they inevitably disguise not only the role but the very existence of the revolutions that produced them. Unless he has personally experienced a revolution in his own lifetime, the historical sense either of the working scientist or of the lay reader of textbook literature extends only to the outcome of the most recent revolutions in the field. Textbooks thus begin by truncating the scientist’s sense of his discipline’s history and then proceed to supply a substitute for what they have eliminated. Characteristically, textbooks of science contain just a bit of history, either in an introductory chapter or, more often, in scattered references to the great heroes of an earlier age. From such references both students and professionals come to feel like participants in a long-standing historical tradition. Yet the textbook-derived tradition in which scientists come to sense their participation is one that, in fact, never existed. For reasons that are both obvious and highly functional, science textbooks (and too many of the older histories of science) refer only to that part of the work of past scientists that can easily be viewed as contributions to the statement and solution of the texts’ paradigm problems. Partly by selection and partly by distortion, the scientists of earlier ages are implicitly represented as having worked upon the same set of fixed problems and in accordance with the same set of fixed canons that the most recent revolution in scientific theory and method has made seem scientific. No wonder that textbooks and the historical tradition they imply have to be rewritten after each scientific revolution. And no wonder that, as they are rewritten, science once again comes to seem largely cumulative.

The decision to reject one paradigm is always simultaneously the decision to accept another, and the judgment leading to that decision involves the comparison of both paradigms with nature and with each other

very existence of science depends upon vesting the power to choose between paradigms in the members of a special kind of community.

As in political revolutions, so in paradigm choice – there is no standard higher than the assent of the relevant community. To discover how scientific revolutions are effected, we shall therefore have to examine not only the impact of nature and of logic, but also the techniques of persuasive argumentation effective within the quite special groups that constitute the community of scientists.

One brief illustration of specialization’s effect may give this whole series of points additional force. An investigator who hoped to learn something about what scientists took the atomic theory to be asked a distinguished physicist and an eminent chemist whether a single atom of helium was or was not a molecule. Both answered without hesitation, but their answers were not the same. For the chemist the atom of helium was a molecule because it behaved like one with respect to the kinetic theory of gases. For the physicist, on the other hand, the helium atom was not a molecule because it displayed no molecular spectrum.7 Presumably both men were talking of the same particle, but they were viewing it through their own research training and practice.

another of the older views, and they are simply read out

The world `out there' is an exceedingly complicated mass of sensations, events, and turmoil. With Thomas Kuhn, I do not believe that the human mind is capable of organizing a structure of ideas that can come even close to describing what is really out there. Any attempt to do so contains fundamental faults. Eventually, those faults will become so obvious that the scientific model must be continuously modified and eventually discarded in favor of a more subtle one. We can expect the statistical revolution will eventually run its course and be replaced by something else.

idiosyncrasy than

Out-of-date theories are not in principle unscientific because they have been discarded. That

I may even seem to have violated the very influential contemporary distinction between “the context of discovery” and “the context of justification.” Can

How could history of science fail to be a source of phenomena to which theories about knowledge may legitimately be asked to apply?

In these and other respects a discussion of puzzles and rules illuminates the nature of normal scientific practice. Yet, in another way, that illumination may be significantly misleading. Though there obviously are rules to which all the practitioners of a scientific specialty adhere at a given time, those rules may not by themselves specify all that the practice of those specialists has in common.

Alexander Bird's Thomas Kuhn (Princeton: Princeton University Press, 2000

In the field of animal behavior, behavioral ecology became “normal science,” in the terminology of the philosopher of science, Thomas Kuhn.116

The term paradigm shift was introduced by Thomas Kuhn in his highly influential landmark book, The Structure of Scientific Revolutions.

Para ser aceptada como paradigma, una teoría debe parecer mejor que sus competidoras; pero no necesita explicar y, en efecto, nunca lo hace, todos los hechos que se puedan confrontar con ella.

Una de las cosas que adquiere una comunidad científica con un paradigma, es un criterio para seleccionar problemas que, mientras se de por sentado el paradigma, puede suponerse que tienen soluciones. Hasta un punto muy elevado, ésos son los únicos problemas que la comunidad admitirá como científicos o que animará a sus miembros a tratar de resolver. Otros problemas, incluyendo muchos que han sido corrientes con anterioridad, se rechazan como metafísicos, como correspondientes a la competencia de otra disciplina o, a veces, como demasiado problemáticos para justificar el tiempo empleado en ellos.

Habiendo visto ya que en las ciencias, hecho y teoría, descubrimiento e invento, no son categórica y permanentemente diferentes, podemos esperar que haya coincidencias entre esta sección y la anterior.

Una vez que ha alcanzado el status de paradigma, una teoría científica se declara inválida sólo cuando se dispone de un candidato alternativo para que ocupe su lugar.

La transición de un paradigma en crisis a otro nuevo del que se pueda surgir una nueva tradición de ciencia normal, está lejos de ser un proceso de acumulación, al que se llegue por medio de una articulación o una ampliación del antiguo paradigma. Es más bien una reconstrucción del campo, a partir de nuevos fundamentos, reconstrucción que cambia algunas de las generalizaciones teóricas más elementales del campo, así como también mucho de los métodos y aplicaciones del paradigma. Durante el periodo de transición habrá una gran coincidencia, aunque nunca completa, entre los problemas que pueden resolverse con ayuda de los dos paradigmas, el antiguo y el nuevo; pero habrá también una diferencia decisiva en los modos de resolución. Cuando la transición es completa, la profesión habrá modificado su visión del campo, sus métodos y sus metas.

Creo que es, sobre todo, en los periodos de crisis reconocida, cuando los científicos se vuelven hacia el análisis filosófico como instrumento para resolver los enigmas de su campo. Los científicos generalmente no han necesitado ni deseado ser filósofos. En realidad, la ciencia normal mantiene habitualmente apartada a la filosofía creadora y es probable que tenga buenas razones para ello. En la medida en que los trabajos de investigación normal pueden llevarse a cabo mediante el empleo del paradigma como modelo, no es preciso expresar de manera explicita las reglas y las suposiciones.

La competencia entre paradigmas no es el tipo de batalla que pueda resolverse por medio de pruebas.

Al comienzo, un nuevo candidato a paradigma puede tener pocos partidarios, y a veces los motivos de esos partidarios pueden resultar sospechosos. Sin embargo, si son competentes, lo mejorarán explorarán sus posibilidades y mostrarán lo que sería pertenecer a la comunidad guiada por él. Al continuar ese proceso, si el paradigma está destinado a ganar la batalla, el numero y la fuerza d ellos argumentos de persuasión en su favor aumentarán. Entonces más científicos se convertirán y continuará la exploración del nuevo paradigma. Gradualmente, el numero de experimentos, instrumentos, artículos y libros basados en el paradigma se multiplicará. Otros hombres más, convencidos de la utilidad de la nueva visión, adoptarán el nuevo método para practicar la ciencia normal, hasta que, finalmente, sólo existan unos cuantos que continúen oponiéndole resistencia. Y ni siquiera podemos decir que estén en un error. Aunque el historiador puede encontrar siempre a hombres que, como Priestley, se mostraron irrazonables al resistirse durante tanto tiempo como lo hicieron, no hallará un punto en el que la resistencia se haga ilógica o no científica. Cuando mucho, puede desear decir que le hombre que sigue oponiendo resistencia después de que se hayan convencido todos los demás miembros de su profesión, deja ipso facto de ser un científico.

Maps and Paradigms. This picture of post-Cold War world politics shaped by cultural factors and involving interactions among states and groups from different civilizations is highly simplified. It omits many things, distorts some things, and obscures others. Yet if we are to think seriously about the world, and act effectively in it, some sort of simplified map of reality, some theory, concept, model, paradigm, is necessary. Without such intellectual constructs, there is, as William James said, only “a bloomin’ buzzin’ confusion.” Intellectual and scientific advance, Thomas Kuhn showed in his classic The Structure of Scientific Revolutions, consists of the displacement of one paradigm, which has become increasingly incapable of explaining new or newly discovered facts, by a new paradigm, which does account for those facts in a more satisfactory fashion. “To be accepted as a paradigm,” Kuhn wrote, “a theory must seem better than its competitors, but it need not, and in fact never does, explain all the facts with which it can be confronted.”4 “Finding one’s way through unfamiliar terrain,” John Lewis Gaddis also wisely observed, “generally requires a map of some sort. Cartography, like cognition itself, is a necessary simplification that allows us to see where we are, and where we may be going.

And for the general public, which wants technologies and cures, the novelties for which science is admired are usually not theoretical at all. That is why Kuhn’s remark sounds somehow wrongheaded.

First, Kuhn single-handedly changed the currency of the word paradigm so that a new reader attaches very different connotations to the word than were available to the author in 1962.

One philosopher, Karl Popper, contended that the limitations of the inferential, experimental method, which characterized science since Bacon, could not establish the truth of a proposition; it could only eliminate the alternative explanations that were tested.13 Thus, “truth” was tentative, waiting to be modified or even upended by the next set of experiments. The other, Thomas Kuhn, contended that, in fact, scientists were not objective seekers of truth, but rather, engaged in confirming the current “truth,” what Kuhn called the prevailing “paradigm” in the discipline. In the practice of what Kuhn called “normal science,” scientists were merely elaborating on this paradigm or using it to explain away any anomalies in their findings. It was only when anomalies accumulate to the point of crisis, when the current paradigm can no longer hold up, that the science opens to new, revolutionary ways of thinking that replace the old.

Secondly, as Kuhn himself stated clearly in his postscript: “The paradigm as shared example is the central element of what I now take to be the most novel and least understood aspect of this book” (186).

Aside from this, we should mention two concepts and two names that are still talking points for academics: the paradigm theory developed by Thomas S. Kuhn and the theory of discourse evolved by Michel Foucault. For the moment, it is unclear whether we should read these explorations as value-free ethnologies in the theoretical field or as critical exposure of discursive conformity.

Encyclopedia

In The Structure of Scientific Revolutions, the philosopher of science Thomas Kuhn observed that scientists spend long periods taking small steps. They pose and solve puzzles while collectively interpreting all data within a fixed worldview or theoretical framework, which Kuhn called a paradigm. Sooner or later, though, facts crop up that clash with the reigning paradigm. Crisis ensues. The scientists wring their hands, reexamine their assumptions, and eventually make a revolutionary shift to a new paradigm, a radically different and truer understanding of nature. Then incremental progress resumes.

Every civilization of which we have records has possessed a technology, an art, a religion, a political system, laws and so on. In many cases those facets of civilizations have been as developed as our own. But only the civilizations that descend from Hellenic Greece have possessed more than the most rudimentary science. The bulk of scientific knowledge is a product of Europe in the last four centuries. No other place and time has supported the very special communities from which scientific productivity comes.

Under normal conditions, the research scientist is not an innovator but a solver of puzzles, and the puzzles upon which he concentrates are just those which he believes can be both stated and solved within the existing scientific tradition.

In The Structure of Scientific Revolutions, Thomas Kuhn noted that scientific discovery is never complete; it goes through predictable stages of evolution. When a theory succeeds at explaining previously unexplainable observations about the world, it becomes a tool that scientists can use to discover even more.

A consensus by itself is meaningless. It was once the consensus that the earth was flat, that the sun orbited the stationary earth, that the Catholic Church was the source of all Truth, that Jesus Christ was God, and that classical physics was almost perfect, bar a fee minor details. All great advances have come about by overturning the consensus. That’s actually the definition of a great advance! To say that no one should be allowed to challenge or doubt the consensus is just about the most serious anti-science statement that anyone can make. That’s turning science into religion, a faith that no one is allowed to question! It’s a simple fact that no matter what the scientific consensus is – and science has been wrong about countless things in its history, and even defines itself according to the principles that all of its claims must be capable of falsification or verification, hence it always places a doubt over itself – the consensus can be completely misguided and mistaken. The dogmatic assertion that it is wrong to spread “doubt and confusion” after “a scientific consensus had been reached” is simply chilling. This is the quintessence of the paradigmatic, blinkered scientific thinking attacked by Thomas Kuhn.

A phenomenon familiar to both students of science and historians of science provides a clue. The former regularly report that they have read through a chapter of their text, understood it perfectly, but nonetheless had difficulty solving a number of the problems at the chapter's end. Ordinarily, also, those difficulties dissolve int he same way. The student discovers, with or without the assistance of his instructor, a way to see his problem as like a problem he has already encountered. Having seen the resemblance, grasped the analogy between two or more distinct problems, he can interrelate symbols and attach them to nature in the ways that have proved effective before. The law-sketch, say f = ma, has functioned as a tool, informing the student what similarities to look for, signaling the gestalt in which the situation is to be seen. The resultant ability to see a variety of situations as like each other, as subjects for f = ma or some other symbolic generalization, is, I think, the main thing a student acquires by doing exemplary problems, whether with a pencil and paper in a well-designed laboratory. After he has completed a certain number, which may vary widely from one individual to the next, he views the situations that confront him as a scientist in the same gestalt as other members of his specialists' group. For him they are no longer the same situations he had encountered when his training began. He has meanwhile assimilated a time-tested and group-licensed way of seeing.