anomalies and crises




Kuhn, Structure, ch. 6


I.  Breakdown of Normal Scientific Traditions

A. Problem:  how do scientific revolutions come about?

1. normal science does not aim at new ways of doing things -- it aims to articulate the paradigm

2. nevertheless, new theories are proposed and replace older theories as a result of normal scientific research

B. For Kuhn, revolutions come about in two ways:

1. either a new fact is discovered that cannot be explained by the old paradigm:  an anomaly

2. or, scientists invent new theories out of dissatisfaction with the kind of answers offered by their old theories

C. For Kuhn, to discover a new fact is at the same time to invent a new theory that accounts for that fact (53)

1. in fact he questions the distinction between fact and theory

2. to make a discovery requires not only that we see that something is but what it is (55)

2. to see what something is involves a process of conceptualizing and theorizing that takes time (53)

a. the process of discovery begins with an awareness of an anomaly:  nature does not agree with our expectations based on our paradigm

b. the process of discovery ends with the making of an adjustment to our theory in such a way as to make what was previously anomalous now expected

1.) a discovery is more than just an addition to our knowledge

2.) it leads us to see things in a new way

II. First example:  the discovery of oxygen involved the invention of a new theory in chemistry

A. Although Priestly had heated cinnabar (mercuric oxide) until it turned to mercury, he had at first thought that the gas released was laughing gas (N2O) (1774) and then "dephlogisticated air" (1775) (54) (Chemistry had developed techniques for separating gases (p. 70)

B. Lavoisier

1. repeats experiment in 1775, calling the gas the "air itself entire," and then again in 1777, calling it "oxygen"

a. called oxygen "atomic principle of acidity"

b. regarded oxygen gas as a compound of oxygen and caloric (55)

2. as long ago as 1772, however, Lavoisier had expressed dissatisfaction with the phlogiston theory (56)

a. Phlogiston theory had problems explaining weight gain in the corrosion of metals

1.) after Newton, one could no longer consider weight as a secondary quality:  conservation of mass (71)

2.) some versions postulated that corroded metals gained the weight of absorbed fire particles; other versions postulated that metals contained phlogiston that had negative mass (72)

b. Lavoisier began to doubt the phlogiston theory and suspect that burning and corrosion involved the combination of something with something else drawn from the atmosphere, rather than the release of phlogiston into the atmosphere (56)

3. his experimental work can be seen as his search for this "something else" that combustion drew from the atmosphere

a. oxygen was something he was prepared to discover, even looking for

b. describe his subsequent experiments with a closed system

III. Second Example:  the discovery of X-rays (57)

A. Roentgen accidentally notices a screen glowing in an unexpected way during experimental work with a cathode ray tube

B. Kuhn compares this case to Lavoisier's performing of experiments that produced results unanticipated by phlogiston paradigm

1. for Kuhn, discovery begins with the perception that something has gone wrong

2. in the case of the phlogiston theory, what went wrong is that metals gained weight when they supposedly gave off phlogiston

3. in the case of x-rays, the screen was not expected to glow

C.  X-ray case is disanalogus with the oxygen case

1. in the x-ray case, no major theoretical change was involved (58)

2. current paradigm in electromagnetic theory did not predict x-rays, but did not rule them out either

D. however, the discovery of x-rays did call into question other experimental work with cathode ray tubes (59)

1. in other words, it changed the normal scientific rules governing instrumentation

2. as Kuhn puts it, scientists had failed to "recognize and control a relevant variable . . .,"

a. e.g., in experiments that turned on the quantity of electromagnetic energy that was emitted from a cathode ray tube, this additional type of energy had not been taken into account

b. experiments would have to be repeated.

IV. Third Example:  the Leyden Jar (61)

A. a "theory-induced" discovery

1. electric fluid theory

2. electrical researchers were trying to store in a jar of water what they thought was the electrical fluid produced by an electrostatic generator (61-62)

B. yet not quite the discovery anticipated by the theory (61)

1. scientists were literally shocked when they touched the water in the jar (62)

2. only later came to realize that the hand holding the jar was acting as a conductor

V.  Anomalies:  General conclusions

A. Kuhn advances the hypothesis that in general, discovery proceeds through:  (see p. 62)

1. awareness of anomaly

2. gradual recognition of what is going on

3. change of paradigm categories and procedures

B. suggests that this process is characteristic of perception

C. Bruner and Postman experiment

1. special deck of cards with red six of spades, black four of hearts, etc. (62-63)

2. subjects experience difficulty:  see pp. 63-64.

D. however, Kuhn is unclear whether he thinks that this experiment reveals how scientists make discoveries, or whether it is only a "metaphor" (64)

E. Nevertheless, Kuhn argues that it is paradigm-guided normal science that makes the discovery of anomalies possible in the first place (65)

1. that is, it is because the paradigm tells us precisely what to expect that the scientist can recognize that something has gone wrong

2. think of the playing cards: 

a. it is precisely because we accept certain things about playing cards that we can recognize funny ones. 

b. someone from a different culture would never see anything wrong

3. similarly, why should it worry anybody that, say, rust weighs more than iron, unless one were in possession of some theory that suggested the contrary?

F. at the same time, because science is guided by paradigms that are not easily given up

1. scientists are not distracted by every anomaly that comes along

2. scientists typically hold onto their paradigms and try to find ways to explain away the anomalies


Crisis and the Emergence of Theories


Kuhn, Structure, ch. 7


I.  Crisis

A. crisis situation may result not only from the discovery of empirical anomalies, but from invention of new theories

1. true, he questioned the distinction between fact and theory

2. nevertheless, discovery of empirical anomalies alone not responsible for such paradigm shifts as (67)

a. Copernicus

b. Newton

c. chemical (Lavoisier)

d. Einstein

e. wave optics

f. thermodynamics

g. Maxwell's electrodynamics

B. new theories invented out of dissatisfaction with way in which reigning paradigm explains the phenomena

1. saw this in the case of Lavoisier

2. Kuhn also mentions how the wave theory of light of Young and Fresnel replaced Newton’s particle theory over concern about anomalies in the way it explained diffraction and polarization (67)

3. and also the Copernican revolution

II. Ptolemy vs. Copernicus (68)

A.  Ptolemy's predictions for the planets were as good as Copernicus's

B.  But the state of Ptolemaic astronomy was a "scandal" (67)

1.  it had become inaccurate with regard to predictions:  precession of the equinoxes (68-69). 

a. external factors, such as need for calendar reform, played a role in making this a crisis (69)

b. Copernicus complained that it could not explain length of year (83)

2.  was incredibly cumbersome as a result of the practice of continuing to add new geometrical constructions to explain away discrepancies (68-69)

3.  Copernicus complains that Ptolemaic theory does not show us

. . . the shape of the universe and the unchangeable symmetry of its parts.  With them it is as though an artist were to gather the hands, feet, head and other members for his images from diverse models, each part excellently drawn, but not related to a single body, and since they in no way match each other, the result would be a monster rather than a man.  (Kuhn 1957, p. 139;  see also Structure p. 83)


C. Copernicus's solution had been anticipated much earlier by Aristarchus; indeed, Copernicus refers to him

III. Example:  Oxygen theory

A. sometimes crisis will come about through a proliferation of different ways to account for the anomaly, as in the case of the phlogiston theory and weight relations (70)

1. phlogiston with negative mass

2. calcining metals gain mass by absorbing fire particles

B. rise of pneumatic chemistry also played a role: realization that air was not the only kind of gas: e.g. that CO2 distinct from normal air

IV. Example:  crisis in Classical Mechanics (72)

A. Leibniz had argued that absolute position, absolute motion play no role in Newtonian mechanics, yet he could suggest no test consequences for relativistic view

B. wave theory of light produced crisis in 1890's (73)

1. it was held that the wave motion took place in a mechanical ether that obeyed Newton's laws

2. at first only measurement of aberration was accurate enough to try to detect it, so normal science turned to trying to measure it this way, but to no avail

3. theorists such as Fresnel and Stokes then turned to various versions of ether drag, which could account not only for failure of aberration experiments but also Michelson-Morley experiment to detect motion through the ether

4. but then there was a proliferation of different versions of the paradigm in order to reconcile ether drag with Maxwell’s electrodynamics, including Lorentz contraction

C. Einstein’s theory of relativity emerges during this crisis

III. Characteristics of a Crisis (75)

A. new theories emerge only when normal science breaks down

B. New theories had been partially anticipated (Leibniz, Aristarchus).  But in the absence of crisis they are ignored (75-76)

C. although from a philosophical point of view it is always possible to formulate alternative theories -- Kuhn asserts this is not even difficult (q.v.) -- this sort of activity is usually undertaken only during crisis periods. (76)



Response to Crisis


Kuhn, Structure, ch. 8


I.  Anomalies and Crises

A. Anomalies do not function like counter-instances to a theory (77).  Arguments:

1. one never rejects a paradigm without accepting an available alternative -- unless one wants to leave science altogether (78, q.v.)

2. one can always come up with ad hoc adjustments to a theory (78) – true of philosophical theories as well

3. theories function like the definitions of the terms that are in them

a. e.g., Newton's second law defines force, mass, acceleration

b. Dalton's chemical law of fixed proportions defines element, compound (79)

c. may say something similar about Kuhn’s own claim that scientists won’t reject paradigms when faced with anomalies or counter-instances: if they did they’d stop being scientists

4. no paradigm ever solves all of its problems

a. those which seem to do so yield no research problems and become mere engineering tools (79, q.v.)

b. counter-instances treated like puzzles (80)

c. ". . . either no scientific theory ever confronts a counterinstance, or all such theories confront counterinstances at all times."

d. it’s a poor carpenter who blames his tools

e. due to nature of science pedagogy, students accept theories on authority of textbooks and teachers, rather than regarding applications as evidence for theories

f. anomalies can be ignored as long as there are other problems to work on (81)

1.) -- e.g., for 60 years after Newton’s work, predicted motion in moon’s perigee was only half that observed

2.) similarly, no one questioned Newtonian mechanics because it could not explain the motion in the the perihelion of Mercury

B. An anomaly may come to be regarded as important and lead to a crisis if:  (82)

1. it questions fundamental generalizations, such as problem of ether drag and Maxwell’s electrodynamics

2. it has practical importance, such as calendar reform (82)

3. new techniques are developed that allow for more precise measurements or new sorts of measurements (e.g., weighing gases), making the discrepancy more apparent

4. the anomaly has been around a long time and scientists have repeatedly failed to solve it – Ptolemaic astronomy, again

5. attempts to solve it have led to a proliferation of versions of the paradigm (83)

a. the proliferation of different versions of a paradigm seems to be the most important way that anomalies lead to crisis; as Kuhn says it is "universal" (84). Scientists don’t know what to do:  see quotation from Pauli

b. N.B.:  Kuhn says that

1.) "the rules of normal science become increasingly blurred" (83)

   and that

2.) "All crises begin with the blurring of a paradigm and the consequent loosening of the rules for normal research."  (84)

C. Crisis is closed in three ways: 

1. normal science solves the anomaly

2. anomaly is set aside again

3. a new paradigm solves the anomaly

D. also speaks of shift in visual gestalt, which he expands on more in ch. 9 and 10 (85)

1. except scientists don’t see something as something else: they simply see it

2. and they don’t have same freedom to switch back and forth

II. Extraordinary Science (86)

A. sometimes a new paradigm emerges in embryo form before a crisis is recognized, as in the case of Lavoisier’s oxygen theory and Young’s wave theory (86)

B. but in other cases, there is a considerable amount of time between recognizing a crisis and the emergence of a new paradigm, as with Copernicus and Einstein

1. these are good cases for the historian studying extraordinary science (86-87)

2. science can seem like a random search, as with Kepler struggling to explain Mars’ orbit (87)

C. During this sort of extraordinary science,

1. scientists may appeal to philosophical analysis and thought experiments to clarify the rules and assumptions implicit in the paradigm

2. this process weakens the grip of the paradigm on their minds (88)

D. e.g., Einstein's very long railroad track struck by lightning at both ends, used to illustrate problems with the notion of simultaneity

E. what they show is not that the concepts in our theories taken by themselves are confused, but that the concepts will lead to confusion when one attempts to apply the theories

F. those who invent new paradigms tend to be young or new to the field (90)