05.Kuhn:ParadigmsandImmatureScience1.Paradigms

Paradigm(broadsense):apackageofideasandmethodswhichmakeupaviewoftheworldandawayofdoingscience.Paradigm(narrowsense):acollectionofexamplesorexemplarsthatserveasmodels,inspiringanddirectingfurtherwork.

TwoCharacteristics (Kuhnpg.10):• "Sufficientlyunprecedentedtoattractanenduringgroupofadherentsawayfromcompetingmodesofscientificactivity."

• "Sufficientlyopen-endedtoleaveallsortsofproblems...toresolve."

ThomasKuhn(1922-1996)

Examples- Aristotelianphysics(Physica ~300B.C.)- Ptolemaicastronomy(Almagest 2ndcent.A.D.)- Newtoniandynamics(Principia 1687)

1.Paradigms2.ImmatureScience3.Characteristics4.TransitiontoNormalScience5.EstablishmentofNormalSci

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Paradigmscharacterize"NormalScience"

Normalscience:Scientificworkthatoccurswithintheframeworkprovidedbyaparadigm.

ConstrastwithPopper

Scientificmethodisbasedonanopennesstocriticism (scientistsmustbewillingtochangetheirviewsinlightoffalsifyingdata)!

Normalscienceassumesno criticismoffundamentalissues!

- well-organized- agreementonfundamentalissues- extensionofparadigmtocover"nooksandcrannies"- no"criticalstances"or"permanentopenness"

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(ii) Changeassociatedwith"revolutionaryscience"- completeoverthrowofdominantparadigm- nostandards- notionofprogressnotsosimple

Scientificchangeproceedsincrementally (viaconjectureandrefutation).

NewtonExample:

MythofhumbleNewton:- Appealtopriscasapientia?- InsulttoshortrivalRobertHooke?

IfIhaveseenfurtheritisbystandingontheshouldersofgiants.

Twotypesofchangeinscience:

- incremental- standardsofjustificationandrationality- simplenotionofprogress

(i)Changewithinnormalscience.

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StorytoCome:ScientificChangeAccordingtoKuhn

normalscience crisis revolutionary

sciencenormalscience⇒ ⇒ ⇒

REVOLUTION!

REVOLUTION!

"Thebeautyandclearnessofthedynamicaltheorywhichassertsheatandlighttobemodesofmotion,isatpresentobscuredbytwoclouds."(a) Blackbodyradiation:justneedtotweakthetheoryjustabit!(b) Etherdriftnullresults:justneedmorepreciseexperiments!

WilliamThomson,LordKelvin(1900)

Blackbodyradiationcanbetheoreticallyexplainedifwesupposeenergycomesindiscretepackets....let'scallthem"quanta"...

MaxPlanck(1900)

Let'ssupposethereisnoether...andthatmeasurementsoftimeandspacearenotabsolute...

AlbertEinstein (1905)

What comes before normal science and dominant paradigms?

*

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Example:HistoryofOptics

(a)~1925-present.CurrentParadigm:QuantumFieldTheory• Lightconsistsofphotons:excitationsofaquantizedelectromagneticfield.

2.ImmatureScience

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(b)1800's-1900's.WaveParadigm• Lightconsistsofwavesintheether.

observationscreen

bandsoflightanddarkaccordingtowhetherwavesinterfereconstructivelyordestructively

see

• ThomasYoung'sDouble-SlitExperiment(1800)ThomasYoung(1773-1829)

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observationscreen

butNo!

shouldsee

(b)1800's-1900's.WaveParadigm• Lightconsistsofwavesintheether.• ThomasYoung'sDouble-SlitExperiment(1800)

ThomasYoung(1773-1829)

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(c)1700's-1800's.ParticleParadigm• Lightconsistsofparticles(Newton1704Optiks)

• Refraction:sin(θi)/sin(θr) = vwater/vair• Explanation:Lightparticleisattractedmoretowardswaterparticlesatinterfaceandthusspeedsup.

θi

θrvwater

vair• Reflection:θi =θr• Explanation:Lightparticlesscatterelastically.

θiθr

mirror

IsaacNewton(1643-1727)

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(d)Pre-Newton

Immature Science

• Nodominantparadigm• Manycompetingparadigms- Descartes'(1637)disturbanceintheplenum.

ReneDescartes(1596-1650)

- Hooke(1660's),Huygens(1678)wavetheories.

ChristiaanHuygens

(1629-1695)

- Gassendi(1660's)particletheory.

PierreGassendi

(1592-1655)

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3.CharacteristicsofImmatureScience• Competingviewsneedtoderiveeverythingfromscatch.• Allfactsseemequallyrelevant.• Collectionsoffactswithnoexplanatoryframework- compendiumsandbeastiaries

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4.TransitiontoNormalScience• Oneparadigmmustseembetterthanitsrivals.• Shouldnotexplainallthefacts:shouldbepotentiallyuseful.• Shouldsuggestwhichexperimentsanddirectionsofresearchareworthpursuing.

• OpticsExample:- Newton'sOptiks (1704).Providestheoreticalframework(Newton'stheoryofmotion)withinwhichopticalphenomenacanbeexplained.

- PrestigeofNewton.

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PotentialProblemWhatistherelationbetweenaparadigmandascientificcommunity?• paradigm= whatmembersofascientificcommunityshare.• scientificcommunity= communityunitedunderasingleparadigm.

• Kuhn(postscript):- identifyscientificcommunityfirst (roleofsociology)- then identifyparadigms

• scientificcommunity="practitionersofascientificspecialty"

- professionalinitiations- commonliterature

- similareducations

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5.EstablishmentofNormalScience

• Professionalreputation- basedonextendingparadigmtonewareas,notonreproducingfundamentalresults(sodon'twritetextbooksforaliving).

• Socialfunctionofaparadigm(Kuhnpg.11):- indoctrinationofstudentsintoscientificcommunity

- samemodels- sameproblems- samemethods

• Roleoftextbooks- serveasindependentexplanationsoffundamentalprinciples.

- practitionersofparadigmdon'thavetoalwaysstartfromscratch.

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Claim:Learningproceedsbyreinforcement:- positivereinforcementestablishesbehavior- negativereinforcementeliminatesbehavior

NormalScienceExample

• Extremeform:All humanbehaviorcanbeexplainedintermsofpurelyobservableresponsestoreinforcement.- Inparticular:Therearenosuchthingsasunobservablemental/cognitivestates.

• Thus: "xfeelspain"means"x exhibitscertainbehaviors"

Question: Howshouldweperformoperationsonnewborns?

• Extremebehaviorist:- Newbornscannotverballycommunicate.- Tosay"Newbornisinpain"means"Newbornexhibitscertainbehaviors".- Thus:Justusemusclerelaxantasanesthetic.

• 1950's.Behaviorismparadigminpsychology. Skinner,B.F.(1953)ScienceandHuman

Behavior

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