Thread by @ReformedTrader

1/ Structure of Scientific Revolutions (Thomas Kuhn)

"A new theory is not chosen because it is true but because of a worldview change. Progress is not a simple line leading to the truth. It is progress away from less adequate conceptions of the world."

amazon.com/Structure-Scie…

2/ This book changed the way the history of science is studied.

It's part of the list "The 100 Most Influential Books Ever Written:"
en.wikipedia.org/wiki/The_100_M…

For related reading, check out the syllabus for Michael Friedman's Stanford course:
web.stanford.edu/class/phil61/

3/ Introductory Essay (Ian Hacking)

"That is the structure of scientific revolutions: normal science with a paradigm and a dedication to solving puzzles; followed by serious anomalies, which lead to a crisis; and finally resolution of the crisis by a new paradigm.

4/ "Incommensurability is the idea that, in the course of a revolution and paradigm shift, the new ideas and assertions cannot be strictly compared to the old ones. Even if the same words are in use, their very meaning has changed."

5/ "Kant had taught that absolute Newtonian space and the principle of uniform causality are a priori principles of thought, necessary conditions on how human beings comprehend the world in which they live.

6/ "Combined, relativity and quantum physics overthrew not only old science but basic metaphysics [from the Newtonian age]. Cause and effect were re-conceptualized as mere appearance, and indeterminacy was at the root of reality.

"Revolution was the order of the scientific day."

7/ "The search for the Higgs particle dedicates money and talent to confirming what present physics teaches—the as yet undetected particle that plays an essential role in the existence of matter. Innumerable puzzles in mathematics and engineering must be solved en route.

8/ "Nothing new in theory or even phenomena is anticipated. Normal science does not aim at novelty. But novelty can emerge from confirmation of theories already held.

"Normal science is characterized by a paradigm, which legitimates puzzles and problems the community works on.

9/ "All is well until the methods legitimated by the paradigm cannot cope with a cluster of anomalies; crisis persists until a new achievement redirects research, serving as a new paradigm.

"Textbooks present facts and techniques but do not enable anyone to become a scientist.

10/ "You are inducted not by the theories but by the problems at the ends of the chapters. You learn that a group of these problems, seemingly disparate, can be solved by using similar techniques. In solving those problems, you grasp how use the “right” resemblances.

11/ “The student discovers a way to see his problem as like one he has already encountered. Once that analogy has been seen, only manipulative difficulties remain.”

"Kuhn was at pains to say that there is seldom such a thing as Popper's simple refutation [falsification].

12/ "We have a tendency to see what we expect, even when it is not there. It takes a long time for an anomaly to be seen for what it is: something contrary to the established order."

The 1960s also gave birth to this view in psychology and economics:

https://twitter.com/ReformedTrader/status/1317876706414227457

13/ "Not every anomaly is taken to matter. In 1827, Robert Brown noticed that floating grains of pollen observed through a microscope constantly jitter around. This was an outlier that simply made no sense until it was incorporated into the theory of the motion of molecules.

14/ "Once understood, this was powerful evidence for the molecular theory, but previously it was a mere curiosity. The same is true of many phenomena that run counter to theory but are just put aside. There are always discrepancies between theory and data, many of them large.

15/ "The recognition of something as a significant anomaly that must be explained—more than a discrepancy that will sort itself out in time—is itself a complex historical event, not a simple refutation."

More on this in relation to the LTCM blow-up:

https://twitter.com/ReformedTrader/status/1282166831608786944

16/ "Poincaré didn't make the connection with Brownian motion. It doesn't pay to be too original in the presence of a star professor: by doing so, Bachelier killed his career. For the rest of his life, disowned by his mentor, he struggled to find work."

https://twitter.com/ReformedTrader/status/1271110594196717569

17/ NOTE: This is a case in point (and I come dangerously close to making an exemplar!).

Brown's work was ignored because it couldn't be conceptualized.

Bachelier solved the problem (en.wikipedia.org/wiki/Brownian_…), but was ostracized; speculation wasn't an acceptable topic to study.

18/ Einstein later became famous because he applied pollen-grain math to a salient problem: the existence of molecules.

The work later became integrated into finance (when we were ready!), but ironically, the problems with IID were not fully explored, leading to LTCM's collapse.

19/ Biases in finance may have kept us from fully exploring issues with existing theories:

https://twitter.com/ReformedTrader/status/1200838353744056320

This should move us to be skeptical concerning consensus views in other fields, especially when communicated through textbooks and news rather than primary sources.

20/ "Theoretical entities get meaning only from the context of a theory. A change in theory must entail a change in meaning: a statement about electrons in the context of one theory means something different from the same string of words in the context of another theory.

21/ "The issue was often debated using the example of mass. The term is essential to both Newton and Einstein. The only sentence everyone remembers from Newton is F = ma. The only one from Einstein is E = mc². But the latter makes no sense in classical mechanics.

22/ "More than one paradigm may emerge, each able to incorporate a different group of anomalies and branch out in new research directions, each with its own achievements on which research is modeled. It is difficult for practitioners of one to understand what the other is doing.

23/ "This is not a deep metaphysical point; it is a familiar fact of life to any working scientist. New disciplines are, to some extent, mutually incomprehensible.

"A revolution changes the domain, changing even the very language in which we speak about some aspect of nature.

24/ "Revolutions progress away from conceptions of the world that have run into cataclysmic difficulties. This is not progress towards a preestablished goal. The “away from” seems to call in question the overarching notion of science as aiming at the truth about the universe.

25/ "Many practitioners of fundamental physics, who might proudly proclaim themselves to be atheists, take for granted that there just is, waiting to be discovered, one full and complete account of nature. This offers itself as an ideal towards which the sciences are progressing.

26/ Kuhn: “Does it really help to imagine that one full, objective, true account of nature and that the proper measure of achievement is the extent to which it brings us closer to that goal?”

"I share Kuhn’s skepticism, but the issues are difficult & not to be decided quickly."

27/ Preface

"I was a graduate student in theoretical physics already within sight of the end of my dissertation. A fortunate involvement with an experimental college course treating physical science for the non-scientist provided my first exposure to the history of science.

28/ "To my surprise, that out-of-date scientific theory and practice undermined my basic conceptions about the nature of science."

"Somehow, astronomy, physics, chemistry, or biology normally fail to evoke controversies over fundamentals endemic among psychologists/sociologists.

29/ "Attempting to discover the source of that difference led me to recognize the role of what I have since called paradigms. These I take to be universally recognized scientific achievements that, for a time, provide model problems and solutions to a community of practitioners."

30/ "Textbooks aim to be persuasive and pedagogic; science drawn from them is no more likely to fit the enterprise that produced them than an image of national culture drawn from a tourist brochure or a language text. This essay attempts to show we have been fundamentally misled.

31/ "Its aim is a sketch of the quite different concept of science that emerges from the historical record of the research activity itself.

"However, it will not be forthcoming if history is scrutinized to answer questions posed by the unhistorical stereotype in science texts.

32/ "Those texts often seem to imply that the content of science is uniquely exemplified by the observations and theories described in their pages.

"Scientific development then becomes the piecemeal process by which these items have been added to an ever-growing stockpile.

33/ "Historians confront difficulties distinguishing the “scientific” component of belief from “error”/“superstition.”

"Aristotelian dynamics, phlogistic chemistry, caloric thermodynamics were not less scientific nor more the product of human idiosyncrasy than today's beliefs.

34/ "If out-of-date beliefs are to be called myths, then myths can be produced (held) by the same sorts of methods (reasons) that now lead to scientific knowledge.

"If they are to be called science, then science has included beliefs quite incompatible with ones we hold today.

35/ "Out-of-date theories are not in principle unscientific because they have been discarded. That, however, makes it difficult to see scientific development as a process of accretion.

"Historians have begun asking about the historical integrity of that science in its own time.

36/ "They ask not about Galileo and modern science, but rather about the relationship between his views and those of his teachers, contemporaries, and immediate successors. They seek the viewpoint that gives those opinions the maximum internal coherence and closest fit to nature.

37/ "The man who is ignorant of a field may reach any one of a number of legitimate but incompatible conclusions.

"His particular conclusion may be determined by his prior experience in other fields, by chance, and by his individual makeup."

Interesting:

https://twitter.com/SteveStuWill/status/1069756255835586560

38/ "What beliefs about the stars, for example, does he bring to the study of chemistry or electricity?

"Which of the many conceivable experiments does he elect to perform first?

"What aspects of the resulting complex observations strike him as particularly relevant?"

39/ "Early schools of thought were all “scientific” but had incommensurable ways of seeing the world. Observation 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.

40/ "An arbitrary element (personal and historical accident) is a formative ingredient of the beliefs espoused by a given scientific community at a given time.

"What are the fundamental entities the universe is made of? How do these interact with each other and with the senses?

41/ "What questions may legitimately be asked, and what techniques employed?

"Answers (or substitutes for answers) are firmly embedded in professional education. That education being rigorous and rigid, these answers come to exert a deep hold on the scientific mind.

42/ "Research is a strenuous and devoted attempt to force nature into the conceptual boxes supplied by professional education.

"Normal science is predicated on the assumption that the scientific community knows what the world is like.

43/ "Much of the enterprise's success derives from the community’s willingness to defend that assumption, if necessary at considerable cost.

"Normal science, for example, often suppresses fundamental novelties because they are necessarily subversive of its basic commitments."

44/ "When 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.

45/ "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."

46/ "For the smaller professional group affected by them, Maxwell’s equations were as revolutionary as Einstein’s and were resisted accordingly.

"The invention of new theories regularly evokes the same response from specialists on whose area of special competence they impinge.

47/ "The new theory implies a change in the rules: it reflects upon work already successfully completed.

"A new theory is seldom just an increment to what is already known. Its assimilation requires the reconstruction of prior theory and the re-evaluation of prior fact."

48/ "The discovery of oxygen or X-rays does not simply add information... until the community has re-evaluated experimental procedures, altered its conception of long-familiar entities, shifted a network of theories.

"Scientific fact and theory are not categorically separable."

49/ " ‘Normal science’ means research firmly based upon one or more past scientific achievements, achievements that some particular scientific community acknowledges for a time as supplying the foundation for its further practice.

"Textbooks expound the body of accepted theory.

50/ "The study of paradigms is what mainly prepares the student for membership in a particular scientific community. Because he joins men who learned their field from the same concrete models, his subsequent practice will seldom evoke overt disagreement over fundamentals.

51/ "That apparent consensus is a prerequisite for normal science.

"In the absence of a paradigm, all of the possible facts seem equally relevant. Early fact-gathering is a far more random activity than the one that subsequent scientific development makes familiar."

52/ "Nature cannot be interpreted in the absence of theoretical/methodological beliefs enabling selection, evaluation, and criticism.

"If that body of belief is not already implicit in the collection of facts—more than “mere facts” being at hand—it must be externally supplied...

53/ "...perhaps by a metaphysic, another science, or personal/historical accident.

"In the early stages of any science, different men confronting the same range of phenomena describe/interpret them in different ways."

NOTE: Sampling/observation are not independent of beliefs.

54/ "A paradigm suggests which experiments are worth performing.

"Both fact collection and theory articulation become highly directed activities.

"There are always some who cling to older views. They are simply read out of the profession, which thereafter ignores their work."

55/ "A scientist can begin research where a textbook leaves off and concentrate exclusively on the most esoteric ideas.

"Papers are addressed to professional colleagues, whose knowledge of a shared paradigm can be assumed & who prove to be the only ones able to read the papers."

56/ "Like a judicial decision, a paradigm is an object for further articulation under new or more stringent conditions.

"Few who are not practitioners of a mature science realize how much mop-up work a paradigm leaves to be done or quite how fascinating such work can prove.

57/ "Mopping-up operations are what engage most scientists throughout their careers. Closely examined, whether historically or in the contemporary laboratory, that enterprise seems an attempt to force nature into the preformed and relatively inflexible box the paradigm supplies.

58/ "Normal science does not aim to call forth new sorts of phenomena; indeed, those that will not fit the box are often not seen at all.

"Nor do scientists normally aim to invent new theories, and they are often intolerant of those invented by others."

citeseerx.ist.psu.edu/viewdoc/downlo…

59/ "By focusing attention upon a small range of relatively esoteric problems, the paradigm forces scientists to investigate some part of nature in a detail and depth that would otherwise be unimaginable.

60/ "We often hear that scientific laws are found by examining measurements undertaken for their own sake and without theoretical commitment. But history offers no support for so excessively Baconian a method.

61/ "Boyle’s experiments were not conceivable (and, if conceived, would have received another interpretation or none at all) until air was recognized as an elastic fluid to which all the elaborate concepts of hydrostatics could be applied.

62/ "Coulomb’s success depended upon his constructing special apparatus to measure the force between point charges. (Those who had previously measured electrical forces using ordinary pan balances, etc., had found no consistent or simple regularity at all.)

63/ "So general and close is the relation between qualitative paradigm and quantitative law that, since Galileo, such laws have often been correctly guessed with the aid of a paradigm years before apparatus could be designed for their experimental determination."

64/ "None of those who questioned the validity of Newton’s work did so because of its limited agreement with experiment and observation. Nevertheless, these limitations of agreement left many fascinating theoretical problems for Newton’s successors.

65/ "Theoretical techniques were required to treat the motions of more than two simultaneously attracting bodies and to investigate the stability of perturbed orbits.

"Problems like these occupied many of Europe’s best mathematicians during the 18th and early 19th centuries."

66/ "Perhaps the most striking feature of normal research problems is how little they aim to produce major novelties, conceptual or phenomenal. Sometimes, as in a wave-length measurement, everything but the most esoteric detail of the result is known in advance.

67/ "Coulomb’s measurements need not, perhaps, have fitted an inverse square law; those who worked on heating by compression were prepared for any one of several results. Yet the range of anticipated, and thus of assimilable, results is small compared with the conceivable range.

68/ "The project whose outcome does not fall in that narrower range is a research failure, one which reflects not on nature but on the scientist.

"In the 18th century, little attention was paid to the experiments measuring electrical attraction with devices like the pan balance.

69/ "Yielding neither consistent nor simple results, they could not be used to articulate the paradigm. They remained mere facts, unrelated and unrelatable to research. Only in retrospect, with a subsequent paradigm, can we see what characteristics of electricity they display.

70/ "Coulomb, possessing this later paradigm, was able to design apparatus that gave a result assimilable by paradigm articulation. But it is also why that result surprised no one and why several of his contemporaries predicted it in advance. Unexpected novelty was not the aim."

71/ "Though its outcome can be anticipated, often in detail so great that what remains to be known is itself uninteresting, the way to achieve that outcome remains very much in doubt. Bringing a normal research problem to a conclusion is achieving the anticipated in a new way.

72/ "It is no criterion of goodness in a puzzle that its outcome be intrinsically important. On the contrary, the really pressing problems, e.g., a cure for cancer or the design of a lasting peace, are often not puzzles at all, largely because they may not have any solution."

73/ "A paradigm provides a criterion for choosing problems that, while the paradigm is taken for granted, can be assumed to have solutions.

"To a great extent, these are the only problems that the community will admit as scientific or encourage its members to undertake.

74/ "Other problems, including many that had previously been standard, are rejected as metaphysical, the concern of another discipline, or sometimes just too problematic to be worth the time.

"A paradigm can even insulate the community from those socially important problems."

75/ "Normal science seems to progress rapidly, as practitioners concentrate on problems that only their own lack of ingenuity should keep them from solving.

"The scientific enterprise, as a whole, does sometimes prove useful, open up new territory, and test long-accepted belief.

76/ "Nevertheless, the *individual* engaged in a normal research is almost never doing any one of these things. 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."

77/ "The electron-scattering maxima that were later diagnosed as indices of electron wave length had no apparent significance when first recorded. Before they became measures of anything, they had to be related to a theory that predicted wave-like behavior of matter in motion.

78/ "The apparatus then had to be redesigned so that the experimental results might be correlated unequivocally with theory. Until those conditions had been satisfied, no problem had been solved.

"Similar restrictions bound admissible solutions to theoretical problems."

79/ "After Descartes’s immensely influential scientific writings, most physical scientists assumed that the universe was composed of microscopic corpuscles and that all natural phenomena could be explained in terms of corpuscular shape, size, motion, and interaction.

80/ "As metaphysical, that commitment told scientists what sorts of entities the universe did and did not contain: there was only shaped matter in motion.

"As methodological, their commitment told them what ultimate laws and fundamental explanations must be like.

81/ "Laws must specify corpuscular motion and interaction, and explanation must reduce any given natural phenomenon to corpuscular action under these laws.

"More important still, the corpuscular conception of the universe told scientists what their research problems should be."

82/ "The practitioners of widely separated fields, say astronomy and taxonomic botany, are educated by exposure to quite different achievements described in very different books.

"Even men in closely related fields may acquire different paradigms in the course of specialization.

83/ "Physical scientists do not all learn the same applications of laws, so they are not all affected in the same ways by changes in practice.

"What quantum mechanics means to each depends upon what courses he has had, what texts he has read, and which journals he studies."

84/ "Normal science does not aim at novelties of fact or theory and, when successful, finds none.

"Until an adjustment of theory is completed—until the scientist has learned to see nature in a different way—a new fact is not quite a scientific fact at all."

85/ "Was it Priestley or Lavoisier, if either, who first discovered oxygen? When *was* oxygen discovered?

"The priority for oxygen has repeatedly been contested since the 1780’s: a symptom of something askew in the image of science that gives discovery so fundamental a role.

86/ "If Priestley was the discoverer, when was the discovery made? In 1774, he thought he had obtained nitrous oxide, a species he already knew. In 1775, he saw the gas as dephlogisticated air: still not oxygen or even, for phlogistic chemists, a quite unexpected sort of gas.

87/ "In 1775, Lavoisier identified the gas only as the “air itself entire.” To the end of his life, Lavoisier insisted that oxygen was an atomic “principle of acidity” and that oxygen gas was formed only when that “principle” united with caloric, the matter of heat.

88/ "Shall we therefore say that oxygen had not yet been discovered in 1777? Some may be tempted to do so. But the principle of acidity was not banished until after 1810, and caloric lingered until the 1860s. Oxygen had become a standard substance before either of those dates."

89/ " “Oxygen was discovered” misleads by suggesting that discovery is a single simple act assimilable to our (questionable) concept of seeing. We too readily assume that discovering, like seeing, should be unequivocally attributable to an individual and to a moment in time."

90/ "Attempts to date a discovery must inevitably be arbitrary because discovery is necessarily a complex event, one which involves recognizing both *that* something is and *what* it is.

"Observation and conceptualization, fact and assimilation to theory, are inseparably linked.

91/ "Only when all the relevant conceptual categories are prepared in advance, in which case the phenomenon would not be of a new sort, can discovering *that* and discovering *what* occur effortlessly, together, and in an instant.

92/ "What Lavoisier announced in his papers from 1777 on was not so much the discovery of oxygen as the oxygen theory of combustion. That theory was the keystone for a reformulation of chemistry so vast that it is usually called the chemical revolution.

93/ "Indeed, if the discovery of oxygen had not been an intimate part of the emergence of a new paradigm, the question of priority from which we began would never have seemed so important.

"The discovery of oxygen was not by itself the cause of the change in chemical theory.

94/ "Long beforehand, Lavoisier had already been convinced that something was wrong with the phlogiston theory and that burning bodies absorbed some part of the atmosphere.

"He was already prepared to discover the nature of the substance combustion removes from the atmosphere.

95/ "That advance awareness of difficulties enabled Lavoisier to see in Priestley’s experiments a gas that Priestley had been unable to see there himself. A major paradigm revision was needed to see what Lavoisier saw. Priestley was, to the end of his long life, unable to see it.

96/ "At what point in Roentgen’s investigation had X-rays had actually been discovered?

"Not at the first instant, when all that had been noted was a glowing screen. At least one other investigator had seen that glow and, to his subsequent chagrin, discovered nothing at all.

97/ "X-rays were greeted with shock. Lord Kelvin at first pronounced them an elaborate hoax. Others were clearly staggered by the discovery.

"Previously completed work would have to be done again because earlier scientists had failed to recognize and control a relevant variable.

98/ "X-rays, to be sure, opened up a new field and thus added to the potential domain of normal science. But they also changed fields that had already existed. In the process, they denied previously paradigmatic types of instrumentation their right to that title."

99/ "Employing a particular piece of apparatus in a particular way assumes only certain sorts of circumstances will arise.

"Uranium fission was hard to recognize: men who knew what to expect chose chemical tests aimed mainly at elements from the upper end of the periodic table."

100/ "One of the competing schools took electricity to be a fluid, and that conception led a number of men to attempt bottling the fluid by holding a water-filled glass vial in their hands and touching the water to a conductor suspended from an active electrostatic generator.

101/ "On removing the jar from the machine and touching the water with his free hand, each of these investigators experienced a severe shock. Those first experiments did not, however, create the Leyden jar. It is again impossible to say just when its discovery was completed.

102/ "The initial attempts worked only because investigators held the vial in their hands while standing on the ground. They had still to learn that the jar required an outer as well as an inner conducting coating and that the fluid is not really stored in the jar at all."

103/ "Novelty emerges only with difficulty, manifested by resistance, against a background provided by expectation.

"The first received paradigm is usually felt to account successfully for most of the observations & experiments easily accessible to that science’s practitioners.

104/ "Further development, therefore, ordinarily calls for the construction of elaborate equipment, the development of an esoteric vocabulary and skills, and a refinement of concepts that increasingly lessens their resemblance to their usual common-sense prototypes.

105/ "That professionalization leads to an immense restriction of the scientist’s vision and considerable resistance to paradigm change. The science becomes increasingly rigid.

"It also leads to a precision of the observation-theory match that could be achieved in no other way.

106/ "Without that special instrumentation, the results that lead ultimately to novelty could not occur. And even when the apparatus exists, novelty emerges only for the man who, knowing with precision what he should expect, is able to recognize that something has gone wrong.

107/ "Anomaly appears only against the background provided by the paradigm. The more precise and far-reaching that paradigm is, the more sensitive an indicator it provides of anomaly and hence of an occasion for paradigm change.

108/ "By ensuring that the paradigm will not be too easily surrendered, resistance guarantees that scientists will not be lightly distracted and that the anomalies that lead to paradigm change will penetrate existing knowledge to the core.

109/ "The fact that a significant scientific novelty so often emerges simultaneously from several laboratories is an index both to the strongly traditional nature of normal science and to the completeness with which that traditional pursuit prepares the way for its own change."

110/ "The state of Ptolemaic astronomy was a scandal before Copernicus’ announcement. Galileo’s contributions to the study of motion depended closely upon difficulties discovered in Aristotle’s theory by scholastic critics.

110/ "Quantum mechanics was born from a variety of difficulties surrounding black-body radiation, specific heats, and the photoelectric effect.

"Because it demands large-scale paradigm destruction and major shifts in the problems and techniques of normal science...

111/ "The emergence of new theories is generally preceded by a period of pronounced professional insecurity generated by the persistent failure of the puzzles of normal science to come out as they should. Failure of existing rules is the prelude to a search for new ones."

112/ "Ptolemaic astronomy was admirably successful in predicting positions of stars and planets. No other ancient system had performed so well; for the stars, it is still widely used today as an approximation; for the planets, Ptolemy’s predictions were as good as Copernicus’s.

113/ "But to be admirably successful is never to be completely successful.

"Predictions made with Ptolemy’s system never quite conformed with the best available observations. Reduction of minor discrepancies constituted principal problems of research for Ptolemy’s successors...

114/ "For some time, astronomers had every reason to suppose that these attempts would be as successful as those that had led to Ptolemy’s system. Given a particular discrepancy, astronomers were invariably able to eliminate it by [adding additional epicycles].

115/ "But astronomy’s complexity was increasing, and a discrepancy corrected in one place was likely to show up in another.

"Astronomers began to recognize that the paradigm was failing when applied to its own problems. That was prerequisite to the search for a new paradigm."

116/ "Previous practice of normal science had given every reason to consider problems all but solved. The sense of failure, when it came, was acute.

"The solution to each problem had been at least partially anticipated, but absent of crisis, those anticipations had been ignored.

117/ "Copernicus’ more elaborate proposal was neither simpler nor more accurate than Ptolemy’s system. Available observational tests, as we shall see more clearly below, provided no basis for a choice between them."

118/ "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 it is not even very difficult to invent such alternates.

119/ "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.

120/ "So long as the tools a paradigm supplies prove capable of solving the problems it defines, science moves fastest through confident employment of those tools. As in manufacture, so in science—retooling is an extravagance to be reserved for the occasion that demands it."

121/ "Even for severe anomalies, though scientists may begin to lose faith and to consider alternatives, they do not renounce the paradigm that has led them into crisis. They do not treat anomalies as counterinstances, though for the philosophy of science, that is what they are.

122/ "After achieving the status of paradigm, a theory is declared invalid only if an alternative is available to take its place. No process yet disclosed by the historical study of scientific development resembles the stereotype of falsification by direct comparison with nature.

123/ "The rejection of a previously accepted theory is always based upon more than a comparison of that theory with the world. The decision to reject one paradigm is always simultaneously the decision to accept another. Both paradigms are compared with nature and with each other.

124/ "Anomalies themselves cannot and will not falsify a theory, for its defenders will do what we have already seen scientists doing when confronted by anomaly. They will devise numerous articulations and ad-hoc modifications of their theory to eliminate any apparent conflict.

125/ "From within a new theory, previous anomalies may seem very much like tautologies, statements that could not conceivably have been otherwise.

"Newton’s second law behaves (for those committed to it) like a purely logical statement that no amount of observation could refute.

126/ "The chemical law of fixed proportion, which before Dalton was an occasional experimental finding of very dubious generality, became after Dalton’s work an ingredient of a definition of chemical compound that no experimental work could by itself have upset."

127/ "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.”

128/ "There is also no research without counterinstances. For what is it that differentiates normal science from science in a crisis state? Not that the former confronts no counterinstances. No paradigm that provides a basis for research completely resolves all its problems.

129/ "The few that have ever done so (geometric optics) ceased to yield research problems and instead became tools for engineering. Excepting those, every problem normal science sees as a puzzle can be seen, from another viewpoint, as a counterinstance and as a source of crisis.

130/ "Copernicus saw as counterinstances what Ptolemy’s other successors had seen as puzzles in the match between observation and theory.

"Einstein saw as counterinstances what Lorentz and Fitzgerald had seen as puzzles in the articulation of Newton’s and Maxwell’s theories."

131/ "Normal science strives to bring theory and fact into closer agreement. That activity can be misunderstood as confirmation/falsification. But its object is to solve a puzzle whose existence assumes the paradigm's validity. Failure discredits the scientist, not the theory.

132/ "The man who reads a science text can easily take the applications to be the evidence for the theory. But science students accept theories on the authority of teacher and text, not because of evidence. What alternatives have they, or what competence?

133/ "The applications given in textbooks assist in learning the paradigm. If set forth as actual evidence, the failure to suggest alternative interpretations or discuss problems for which scientists have failed to produce solutions would convict the authors of extreme bias."

134/ "Persistent and recognized anomaly does not always induce crisis. No one seriously questioned Newtonian theory because of the long-recognized discrepancies between predictions from that theory and both the speed of sound and the motion of Mercury.

135/ "The first was unexpectedly resolved by experiments on heat undertaken for a different purpose; the second vanished with general relativity after a crisis that it had had no role in creating.

"Neither was sufficiently fundamental to evoke the malaise that goes with crisis."

136/ "(The scientist who pauses to examine every anomaly he notes will seldom get significant work done.)

"Scientists may come to view a crisis's resolution as the subject matter of their discipline. For them, the field will no longer look quite the same as it had earlier."

137/ "The transition from a paradigm in crisis to a new one is not achieved by an extension of the old paradigm. Rather, it is a reconstruction of the field from new fundamentals, changing some of the most elementary theoretical generalizations, methods, and applications."

138/ "The scientist does not preserve the gestalt subject’s freedom to switch back and forth between ways of seeing (bird to antelope or vice versa). Nevertheless, the switch of gestalt is a useful elementary prototype for what occurs in full-scale paradigm shift."

139/ "Since no experiment can be conceived without some sort of theory, the scientist in crisis will constantly try to generate speculative theories that, if successful, may disclose the road to a new paradigm and, if unsuccessful, can be surrendered with relative ease."

140/ "Men who achieve fundamental inventions are almost always very young or very new to the field.

"Being little committed to the traditional rules of normal science, they are particularly likely to see that those rules no longer apply, to conceive another set to replace them."

141/ "Scientific revolutions need seem revolutionary only to those whose paradigms are affected. To outsiders they may seem to be normal parts of the developmental process.

"Astronomers could accept X-rays as a mere addition to knowledge, for their paradigms were unaffected."

142/ "The paradigm's role is necessarily circular. Each group uses its own paradigm to argue in that paradigm’s defense.

"However psychologically persuasive, a circular argument cannot even be made probabilistically compelling for those who refuse to step into the circle."

143/ "New discoveries emerge only to the extent that predictions prove wrong.

"The discovery's importance may be proportional to the stubbornness of the anomaly. There is a conflict between the paradigm that discloses anomaly and the one that later renders the anomaly lawlike."

144/ "If new theories are called forth to resolve anomalies in the relation of an existing theory to nature, the successful new theory must permit predictions that are different from those derived from its predecessor. That could not occur if the two were logically compatible."

145/ "Energy conservation, which today seems a logical superstructure that relates to nature only through independently established theories, developed historically through paradigm destruction/a crisis (incompatibility between Newtonian dynamics and the caloric theory of heat).

146/ "Only after the caloric theory had been rejected could energy conservation become part of science.

"And only after it had been part of science for some time could it come to seem a theory of a logically higher type, one not in conflict with its predecessors."

147/ "The objection to our argument: No theory can conflict with one of its special cases. If Einsteinian science seems to make Newtonian dynamics wrong, that is because some Newtonians were so incautious as to claim entirely precise results or validity at very high velocities.

148/ Objection continues: "In so far as Newtonian theory was ever supported by valid evidence, it still is. Only extravagant claims—never properly parts of science—can have been shown by Einstein to be wrong. Purged of those claims, Newtonian theory has never been challenged."

149/ "But carried just a step further (and the step can scarcely be avoided once the first is taken), such a limitation prohibits the scientist from claiming to speak “scientifically” about any phenomenon not already observed.

150/ "Even in its present form, the restriction forbids the scientist to rely upon a theory whenever his research enters an area or seeks precision for which past practice offers no precedent. The result would be the end of the research through which science may develop further."

151/ "If existing theory binds the scientist only with respect to existing applications, then there can be no surprises, anomalies, or crises. But these are just the signposts that point the way to extraordinary science.

152/ "If positivistic restrictions on the range of a theory’s legitimate applicability are taken literally, the mechanism that tells the scientific community what problems may lead to fundamental change must cease to function.

153/ "There is also a revealing logical gap in the positivist's argument.

"Can Newtonian dynamics really be *derived* from relativistic mechanics?

"The physical referents of these Einsteinian concepts not identical with those of the Newtonian concepts that bear the same name.

154/ "Newtonian mass is conserved; Einsteinian is convertible with energy. Only at low relative velocities may they be measured the same way. Even then, they must not be thought of as the same.

"Unless we change basic definitions, what we have derived is not Newtonian.

155/ "We cannot properly be said to have derived Newton’s Laws, at least not in any sense of “derive” now generally recognized.

"The “derivation” does explain why Newton’s Laws seemed to work. It justifies an automobile driver acting as though he lives in a Newtonian universe.

156/ "An argument of the same type is used to justify teaching earth-centered astronomy to surveyors. But the argument has still not done what it purported to do. It has not, that is, shown Newton’s Laws to be a limiting case of Einstein’s.

157/ "This need to change the meaning of familiar concepts is central to the revolutionary impact of Einstein’s theory. The conceptual transformation is destructive to the previously paradigm.

"Some old problems may be relegated to another science or declared “unscientific.”

158/ "Others that were previously nonexistent or trivial may, with a new paradigm, become the very archetypes of significant scientific achievement. As the problems change, so, often, does the standard that distinguishes a real scientific solution from metaphysical speculation."

159/ "To say that a stone fell because its “nature” drove it toward the center of the universe had been made to look a word-play, something it had not previously been.

"By the 1740s, one could speak of the attractive “virtue” of the electric fluid without inviting ridicule.

160/ "As they did so, electrical phenomena increasingly displayed an order different from the one they had shown when viewed as the effects of a mechanical effluvium that could act only by contact.

161/ "The phenomenon we now call charging by induction could now be recognized. Previously, when seen at all, it had been attributed to the direct action of electrical “atmospheres” or to the leakages inevitable in any electrical laboratory.

162/ "Chemists who believed in these differential attractions between chemical species set up previously unimagined experimetns and searched for new sorts of reactions. Without this, the later work of Lavoisier and Dalton would be incomprehensible.

163/ "Changes in standards governing permissible problems, concepts, and explanations can transform a science.

"Phlogiston explained why the metals were so much alike, and we could have developed a similar argument for the acids.

164/ "But Lavoisier's reform did away with chemical 'principles,' depriving chemistry of actual and potential explanatory power. To compensate, standards were changed. During much of the 19th century, failure to explain the qualities of compounds was no indictment of a theory."

165/ "The case for cumulative development of science's problems and standards is even harder to make than the case for cumulation of theories.

"What occurred was neither a decline nor a raising of standards, but simply a chance demanded by the adoption of a new paradigm.

166/ "Einstein succeeded in explaining gravitational attractions, and that explanation has returned science to a set of canons and problems that are, in this particular respect, more like those of Newton's predecessors than of his successors.

167/ "Quantum mechanics reversed the methodological prohibition that originated in the chemical revolution.

"Space is no longer the inert and homogenous substratum in Newton's and Maxwell's theories; some of the new properties are not unlike those once attributed to the ether."

168/ "To the extent that two scientific schools disagree about what defines legitimate problems and solutions, they inevitably talk past each other when debating the merits of their respective paradigms."

169/ "In the partially circular arguments that regularly result, each paradigm will be shown to satisfy more or less the criteria that it dictates for itself and to fall short of a few dictated by its opponent.

170/ "Since no paradigm ever solves all the problems it defines, and since no two paradigms leave the same problems unsolved, debates must ask which problems are more significant to have solved.

"That question of values can only be answered with criteria outside normal science."

171/ "What were ducks in the scientist's world before the revolution are rabbits afterward. He who first saw the exterior of a box from above later sees its interior from below.

"Looking at a contour map, the student sees lines on paper; the cartographer, a picture of a terrain.

172/ "Looking at a bubble chamber photograph, the student sees confused and broken lines; the physicist, a record of familiar subnuclear events.

"Only after a number of transformations of vision does the student become an inhabitant of the scientist's world.

173/ "That world is determined jointly by the environment and the particular normal-scientific tradition the student has been trained to pursue.

"Therefore, at times of revolution, when the tradition changes, the scientist's perception of his environment must be re-educated."

174/ "When Galileo reported that the pendulum's period was independent of amplitude for angles as great as 90°, his view of the pendulum led him to see far more regularity than we can now discover there.

"New perceptual possibilities had been made available by a paradigm shift."

175/ "Paradigms are not corrigible by normal science. Instead, normal science ultimately leads only to recognition of anomalies and to crises. These are terminated, not by deliberation and interpretation, but by sudden and unstructured events like the gestalt switch.

176/ "Scientists often speak of '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, illumination comes in sleep."

177/ "Galileo saw the swinging stone differently. Archimedes' work on floating bodies made the medium non-essential, the impetus theory rendered the motion symmetrical and enduring, and Neoplatonism directed Galileo's attention to the motion's circular form.

178/ "He therefore measured only weight, radius, angular displacement, and time per swing: precisely the data that could be interpreted to yield Galileo's laws for the pendulum.

"Given his paradigms, pendulum-like regularities were very nearly accessible to inspection.

179/ "How else are we to account for his discovery that the bob's period is entirely independent of amplitude, a discovery that normal science stemming from Galileo had to eradicate and that we are unable to document today?"

Today's pendulum equations:
en.wikipedia.org/wiki/Pendulum#…

180/ "Regularities that could not have existed for an Aristotelian (and that are, in fact, nowhere precisely exemplified by nature) were consequences of immediate experience for the man who saw the swinging stone as Galileo did.

181/ "Contemplating a falling stone, Aristotle saw a change of state rather than a process. For him, the relevant measures were therefore total distance covered and total time elapsed, parameters which yield what we now call not speed but average speed.

182/ "Similarly, because the stone was impelled by its nature to reach its final resting point, Aristotle saw the relevant parameter as the distance *to* the final end point rather than *from* the origin of motion. Those conceptual parameters underlie his 'laws of motion.'

183/ "Scholastic criticism changed this way of viewing motion. A stone moved by impetus gained more and more of it while receding from its starting point; distance from rather than distance to became the relevant parameter.

184/ "In addition, speed was bifurcated into concepts that later became our average speed and instantaneous speed.

"When seen through the paradigm of which these conceptions were a part, the falling stone, like the pendulum, exhibited its governing laws almost on inspection.

185/ "Galileo was not one of the first to suggest that stones fall with a uniformly accelerated motion. Furthermore, he had developed his theorem together with many of its consequences before he experimented with an inclined plane."

186/ "The duck-rabbit shows that men with the same retinal impressions can see different things; inverting lenses [upside-down goggles] show that men with different retinal impressions can see the same thing.

"Psychology supplies a great deal more evidence to the same effect."

187/ "If oxygen and nitrogen were not chemically combined, the heavier gas should settle to the bottom. Dalton, taking the atmosphere to be a mixture, was not satisfactorily able to explain oxygen's failure to do so. His theory created an anomaly where there had been none before.

188/ "While solutions were perceived as compounds, no amount of experimentation could by itself have produced the law of fixed proportions.

"Given obvious counterinstances (glass, salt in water), no generalization was possible without first abandoning affinity theory's concepts.

189/ "Where Berthollet saw a compound that could vary in proportion, Proust saw only a physical mixture. To that issue, neither experiment nor a change in definitional convention could be relevant. They were as fundamentally at cross purposes as Galileo and Aristotle had been."

190/ "Until the last stages, Dalton was neither a chemist nor interested in chemistry. He was a meteorologist investigating the (for him) physical problems of the absorption of gases by water and of water by the atmosphere.

"He approached the problems with a different paradigm.

191/ "To solve the problem, he wanted to determine the relative sizes and weights of the atomic particles. It was to determine these sizes and weights that Dalton finally turned to chemistry, supposing from the start that atoms could only combine in simple whole-number ratios.

192/ "That assumption did enable him to determine the sizes and weights, but it also made the law of constant proportion a tautology.

"For Dalton, any reaction in which the ingredients did not enter in fixed proportion was ipso facto not a chemical process.

193/ "A law that experiment could not have established before Dalton's work became, once that work was accepted, a constitutive principle that no single set of chemical measurements could have upset.

194/ "Chemists stopped writing that two oxides contained 56% carbon and 72% oxygen by weight. Instead, they wrote that one weight of carbon combined either with 1.3 or 2.6 weights of oxygen. When old manipulations were re-recorded this way, a 2:1 ratio leaped to the eye."

195/ "What chemists took from Dalton was not new experimental laws but a new way of practicing chemistry. (He himself called it the 'new system of chemical philosophy.')

"It is hard to make nature fit a paradigm. That is why the puzzles of normal science are so challenging...

196/ "also why measurements undertaken without a paradigm so seldom lead to any conclusions at all.

"Chemists could not simply accept Dalton's theory on the evidence, for much of that was still negative. Instead, after accepting the theory, they had to beat nature into line...

197/ "a process which took almost another generation. When it was done, even the percentage composition of well-known compounds was different. The data themselves had changed.

"In this sense, we can say that after a revolution, scientists work in a different world."

198/ "Both scientists and laymen take much of their image of creative scientific activity from textbooks and other popularizations, authoritative sources that systematically disguise (partly for functional reasons) the existence and significance of scientific revolutions.

199/ "These record the stable *outcome* of past revolutions and thus display the bases of current normal-scientific tradition.

"To fulfill their function, they need not provide authentic information about the *way* in which those bases were first recognized and then embraced.

200/ "In the case of textbooks, there are even good reasons why, in these matters, they should be systematically misleading.

"Textbooks contain just a bit of history, either in an introductory chapter or, more often, in scattered references to great heroes of an earlier age.

201/ "They refer only to that part of the work of past scientists that can be easily viewed as contributions to the statement and solution of the texts' paradigm problems.

202/ "Partly by selection, partly by distortion, 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 method has made to seem scientific.

203/ "Textbooks and the historical tradition they imply have to be rewritten after each scientific revolution. As they are rewritten, science once again comes to seem largely cumulative.

204/ "Scientists are affected by the temptation to rewrite history, partly because the results of scientific research show no obvious dependence upon historical context, and partly because, except during crisis/revolution, the scientist's contemporary position seems so secure.

205/ "Why dignify what science's best and most persistent efforts have made it possible to discard?

"The sciences do need their heroes and do preserve their names. Instead of forgetting these heroes, scientists have been able to forget or revise their works."

206/ "Newton wrote that Galileo had discovered that the constant force of gravity produces a motion proportional to the square of time. In fact, Galileo's kinematic theorem does take that form when embedded in the matrix of Newton's concepts. But Galileo said nothing of the sort.

207/ "His discussion rarely alludes to forces, much less to a uniform gravitational force causing bodies to fall.

"By crediting to Galileo the answer to a question that Galileo's paradigms did not permit to be asked, Newton's story hides a small but revolutionary reformulation.

208/ "It is just this sort of change that accounts, far more than empirical discoveries, for the transition from Aristotelian to Galilean and from Galilean to Newtonian dynamics.

"By disguising such changes, the textbook tends to make the development of science look linear."

209/ "But that is not the way a science develops. Many of the puzzles of contemporary normal science did not exist until after the most recent scientific revolution. Very few of them can be traced back to the historic beginning of the science within which they now occur.

210/ "The whole network of fact and theory that the textbook paradigm fits to nature has shifted.

"Is constant acceleration produced by constant force a mere fact students have always sought, or is it rather the answer to a question that first arose only within Newtonian theory?

211/ "Theories do 'fit the facts,' but only by transforming previously accessible information into facts that, for the previous paradigm, had not existed at all.

"The knowledge-mediated relationship between science and nature changes with each revolutionary reformulation."

212/ "No theory ever solves all the puzzles with which it is confronted, nor are any solutions often perfect.

"It is the incompleteness of the existing data-theory fit that defines many of the puzzles that characterize normal science.

213/ "If any failure to fit were the ground for rejection, all theories ought to be rejected at all times. But if only severe failure justifies rejection, the Popperians will require some criterion of "degree of falsification;" then they will encounter a network of difficulties."

214/ "Because it is a transition between incommensurables, the transition between paradigms cannot be made one step at a time, forced by knowledge and neutral experience. Like the gestalt switch, it must occur all at once (though not necessarily in an instant) or not at all."

215/ "Copernicanism made few converts for almost a century after Copernicus's death. Newton's work was not generally accepted for more than half a century. Priestly never accepted the oxygen theory, nor Lord Kelvin the electromagnetic theory, and so on."

216/ Max Planck: "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."

"This is too commonly known to need further emphasis."

217/ "Individual scientists embrace a new paradigm for all sorts of reasons and usually for several at once (for example, the sun worship that helped make Kepler a Copernican).

"Some depend on the idiosyncrasies of autobiography and personality."

218/ "There are also reasons that appeal to the individual's sense of the appropriate or the aesthetic: the new theory is said to be 'neater,' 'more suitable,' or 'simpler' than the old one.

"To see the importance of this, remember what a paradigm debate is about.

219/ "A new candidate for a paradigm has seldom solved more than a few of the problems that confront it, and most of those solutions are still far from perfect.

"Until Kepler, the Copernican theory scarecely improved upon the predictions of planetary position made by Ptolemy."

220/ "Ordinarily, it is only after the new paradigm has been developed, accepted, and exploited that apparently decisive arguments (the Foucault pendulum or the Fizeau experiment) are developed. Producing them is part of normal science; its role is in post-revolutionary texts."

221/ "During the debate itself, the opponents of a new paradigm can legitimately claim that even in the area of crisis, it is little superior to its traditional rival. The older paradigm can presumably be articulated to meet the new challenges.

222/ "Tycho Brahe's earth-centered astronomical system and later versions of the phlogiston theory were successful responses to challenges posed by new paradigm candidates.

"There are also problems the new rival has not solved but that are not problems at all for the old view.

223/ "Until the discovery of water, the combustion of hydrogen was a strong argument for the phlogiston theory and against Lavoisier's. And even after the oxygen theory had triumphed, it still could not explain the preparation of a combustible gas from carbon."

224/ "The man who embraces a new paradigm at an early stage must often do so in defiance of evidence. He must believe it will succeed with its many large problems, knowing only that the older paradigm has failed with a few.

"A decision of that kind can only be made on faith."

225/ "Something must make at least a few scientists feel the new proposal is on the right track, and sometimes only personal and inarticulate aesthetic considerations can do that.

"When first introduced, neither Copernicus's nor De Broglie's theories had much other appeal.

226/ "Even today, Einstein's general theory attracts men primarily on aesthetic grounds, an appeal few people outside of mathematics are able to feel.

"If the paradigm is to win its fight, the number and strength of persuasive arguments in its favor will eventually increase."

227/ "Those who rejected Newtonianism proclaimed its reliance on innate forces would return science to the Dark Ages.

"A similar, though more moderate, feeling seems to underlie the opposition of Einstein & Bohm to the dominant probabilistic interpretation of quantum mechanics.

228/ "In short, it is only during periods of normal science that progress seems both obvious and assured. During those periods, however, the scientific community could view the fruits of its work in no other way.

229/ "Scientific progress is not different in kind than progress in other fields, but its absence most times of competing schools that question each others' aims and standards makes the progress of a normal-scientific community far easier to see.

230/ "Once the reception of a common paradigm frees the community from the need to constantly re-examine first principles, members can concentrate exclusively on the most esoteric phenomena that concern it. That increases the efficiency with which the group solves new problems.

231/ "Because works for an audience of colleagues who share his own values and beliefs, the scientist can take a single set of standards for granted. He need not worry about what some other group will think & can therefore dispose of one problem & get on to the next more quickly.

232/ "The insulation of the scientific community from society permits the scientist to concentrate attention on problems he has good reason to think he can solve.

"Unlike the engineer, doctor, and theologian, the scientist need not choose problems that urgently need solutions."

233/ "In most fields, the practitioner learns by exposure to the work of other artists, 'classic' works, and primary sources. Textbooks have only a secondary role. The student constantly sees competing, incommensurable approaches, which he must ultimately evaluate for himself.

234/ "Contrast this with natural sciences, in which the student relies mainly on textbooks, which are systematically substituted for the creative scientific literature that made them possible.

"Given the confidence in their paradigms, few scientists would wish to change this.

235/ "Why, after all, should the student of physics read the works of Newton, Faraday, Einstein, or Schrodinger, when everything he needs to know about these works is recapitulated in a far briefer, more precise, and more systematic form in a number of up-to-date textbooks?

236/ "It is a narrow, rigid education, probably more so than any other except perhaps in orthodox theology. But for normal-scientific work, for puzzle-solving within the tradition that the textbooks define, the scientist is almost perfectly equipped."

237/ "As long as somebody appears with a new candidate for paradigm (usually one young or one new to the field), the loss due to rigidity accrues only to the individual. Individual rigidity is compatible with a community switches from paradigm to paradigm on a generational basis.

238/ "That very rigidity provides the community with a sensitive indicator when something has gone wrong."

"Revolutions close with a total victory for one of the two opposing camps. Will that group ever say that the result of its victor has been something less than 'progress'?

239/ "Scientific education makes use of no equivalent for the art museum or the library of classics. The result is a sometimes drastic distortion in the scientist's perception of his discipline's past. He comes to see it as progress that occurs in a straight line.

240/ "There are losses as well as gains in scientific revolutions. Scientists tend to be peculiarly blind to the former.

"We may need to relinquish the notion that changes of paradigm carry scientists and those who learn from them closer and closer to the truth.

241/ "Science's development is a process of evolution *from* primitive beginnings: a process whose successive stages are characterized by an increasingly detailed and refined understanding of nature. But nothing that has been or will be said makes it evolution *toward* anything.

242/ "If we can learn to substitute evolution-from-what-we-do-know for evolution-toward-what-we-wish-to-know, a number of vexing problems may vanish in the process. Somewhere in this maze, for example, must lie the problem of induction."

243/ "What must nature, including man, be like in order that science be possible at all?

"It is not only the scientific community that must be special. The world of which that community is a part must also possess quite special characteristics.

244/ "That problem ("What must the world be like in order that man may know it?") was not created here. It is as old as science itself.

"Any conception of nature compatible with the growth of science by proof is compatible with the evolutionary view of science developed here."

245/

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