Kuhn: Science Paradigm

Kuhn turns attention from the “product” of science to the “process” 

of science. 

He seems to denythat 

(1) Rationality is the drivingforce behind scientific change. 

(2) New theories represent “the world” more accurately than old theories do.

Normal vs. revolutionaryscience 

Kuhn says there are two kinds of science: 

Normalscience is “researchfirmlybasedupon one or more 

scientific achievements, achievements that 

some particular scientific community 

acknowledges for a time as supplying 

the foundation for its future practice” (10). 

Revolutionaryscience occurs when normal science breaks down, 

because the exemplaryachievements of the 

past no longer give enoughguidance 

about what should happen next. 

Normal science andparadigms

A paradigm that is successful (for a time) has “attract[ed] an 

enduringgroupof adherents awayfrom competingmodes of 

scientific activity” and is “sufficientlyopen­ended to leave all sorts 

of problems for the . . . groupofpractitioners to solve” (10). 

Anomalies 

Anomalies are ways that “nature has somehow violated the 

paradigm­inducedexpectations that govern normal science” (53). 

Phlogiston theorysays burning“liberates” phlogiston that had 

been bonded with“ash.” But then whydo some things gain 

weight when burned? 

Roentgen’s discoveryof X­rays: “Though X­rays were not 

prohibited byestablishedtheory, they violated deeply 

entrenched expectations. . . Perhaps those rays . . . were 

implicatedin behavior previouslyexplained without reference 

to them” (59). 

Crisis

“[E]arlyattacks upon the resistant problem willhave followedthe 

paradigm rules quite closely. But withcontinuingresistance, more 

andmore of the attacks upon it will have involved some minor or 

not so minor articulations ofthe paradigm, no two ofthem quite 

alike, each partiallysuccessful, but none sufficientlyso to be 

acceptedas paradigm bythe group” (83). 

Example: competingsystems of epicycles. 

The breakdown ofa paradigm

“Through this proliferation of divergent articulations (more and 

more they willcome to be described as adhoc adjustments), the 

rules of normal science become increasinglyblurred. Thoughthere 

is still a paradigm, few practitioners prove to be entirelyagreed 

about what it is. Even formerlystandardsolutions of solved 

problems are calledin question” (83). 

Revolution

“The resultingtransition to a new paradigm is scientific revolution” 

(90), suchas the transition to special relativityin the earlypart of 

the twentiethcentury. 

The crisis is “terminated, not bydeliberation and interpretation, but 

bya relativelysudden and unstructured event like the gestalt switch 

[e.g., the change from seeingan illustration as a rabbit to seeingit as 

a duck]. Scientists then often speak ofthe ‘scales fallingfrom the 

eyes’ or ofthe ‘lightningflash’ that ‘inundates’ a previouslyobscure 

puzzle, enablingits components to be seen in a new waythat for the 

first time permits its solution” (122). 

Kuhn’s descriptive picture, in a nutshell

Normal science consists of solvingpuzzles that the dominant 

paradigm guarantees have answers, until an anomalyis discovered. 

Certain anomalies cause a crisis. Generally, crises bringabout the 

development and adoption ofa new paradigm. 

Note: this is all technical vocabulary—and the interpretation of 

much ofit is controversial! 

MIT lecture notes Reason Relativity and Reality