17.explanation causal unifying - poly
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17.SciExplanation:UnificationandCausalAccounts1.UnificationAccount
• Intuition:Toexplainistoconnectadiversesetoffactsbysubsumingthemunderasetofbasicclaims.
UnificationAccount:Toexplainsomethingistodemonstratehowitbelongstothemostunifyingsystematizationofthesetofclaimscurrentlyendorsedbythescientificcommunity.
• Asystematization Σ ofasetofclaimsisasubsetofthoseclaimsfromwhichtherestcanbederived(likeatheory).
• Σ isunifying ifitmaximizesscope,simplicityandstringency.- ScopemeasuresthenumberofconclusionsthatcanbedrawnfromΣ.- SimplicitymeasuresthesizeofΣ.- StringencymeasurestherangeofapplicabilityofΣ.
1.UnificationAccount2.CausalAccount
Friedman,M.(1974)"ExplanationandScientificUnderstanding"Kitcher,P.(1981)"ExplanatoryUnification"
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• GeneralIdea:Toscientificallyexplainafact,youhavetodemonstratehowitcanbeembeddedinaunifyingtheory.- Maxwell'stheoryofelectromagnetismprovidesunifyingexplanationsofelectricandmagneticphenomena.
- TheStandardModelprovidesunifyingexplanationsofphenomenathatexperiencetheelectromagnetic,strong,andweakforces.
• Intuition:Unifyingpowerisacharacteristicofascientifictheory.
Generalrelativity:- Aunifyingsystematizationofclaimsaboutthelargescalestructureofspace,timeandmatter.
- Hasgreatscope,greatsimplicity,andgreatstringency(itonlyappliestophenomenathatexperiencegravity,anditprescribesthebehaviorofsuchphenomenainveryrestrictedways).
Astrology:- Asystematizationofclaimsabouthumanbehaviorbasedonthelargescalestructureofspace,timeandmatter.
- Notallthatstringent(yourhoroscopeistypicallyflexibleenoughtoaccountforanyeventyoumightexperienceinagivenday).
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Ex:Whydoesaheliumballoonfloattowardsthefrontofanacceleratingairplaneasittakesoff?
Unifyingexplanation:AccordingtothePrincipleofEquivalencefromGeneralRelativity,auniformlyacceleratingframeisindistinguishablefromaframeatrestinahomogeneousgravitationalfielddirectedintheoppositedirection.Sotheacceleratingplaneisindistinguishablefromaplaneatrestinagravitationalfielddirectedtowardsitsrear.Andaheliumbaloonfloatsupward,awayfromthegravitationalsourceinsuchaframe;inthiscase,towardthefrontofthecabin.
a≠0
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ThreeCharacteristicsoftheUnificationAccount
(a)Expectabilitythesis• Aunifyingexplanationshowshowtheexplanandum istobeexpectedfromtheexplanans.- But:Notnecessarilynomic (i.e.,lawlike)expectability.- Idea:Theunificationaccountreplacesthe"law"inthecoveringlawaccountwitha"unifyingsystematization"(i.e.,theory).
(b)Notnecessarilyreductionistic• Aunifyingexplanationdoesnotneedtorefertoafundamental"grandunifiedtheory".- Aunifyingexplanationofabiologicalfactdoesn'tnecessarilyhavetoshowthatitcanbereducedtochemistryandphysics.
(c)Global
• Aunifyingexplanationembedsalocal factinalarger,global theoryorframework.
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Advantages• Recalltheflagpoleanditsshadow:- Thecoveringlawaccountallowstheflagpole'sheighttobeexplainedbythelengthofitsshadow(whichseemswrong).- Theunificationaccountavoidsthis!
Intuition:Asystematization/theory(setofclaims)ismoreconstrainedthanasingleclaim(law).- Thus:Explanationsbasedonsystematizationscanbemoreconstrainedthanexplanationsbasedonlaws.
Claim:Anexplanationofaflagpole'sheightintermsofitsshadowisnotaunifyingexplanation:- Itrequiresalarger(lesssimple)systematization(i.e.,"theory")ofobjectsandshadowsthananexplanationoftheshadow'slengthintermsoftheflagpole'sheight.
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TwoProblemsfortheUnificationAccount
(i)Problemofsubjectivestandards• Howarewetojudgewhichexplanationsaremoreunifyingthanothers?- Howdoweidentifythesystematization(theory)thatmaximizesscope,simplicity,andstringency?
(ii)Problemofprobabilisticexplanations• Somelegitimateexplanationsgivealowprobabilitytotheirexplananda;hencetheirexplananda arenotexpectedfromtheirexplanans.- Anyaccountthatadoptstheexpectabilitythesisfacesthisproblem:recallthesyphilisandparesiscounterexampleforthecoveringlawaccount.
One response: Deductive Chauvinism...
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Claim(DeductiveChauvinism):Allprobabilisticexplanationsarereducible.
Twotypesofprobabilisticexplanation(a) Reducible:Givenenoughinformation,theexplanandum canbe
logicallydeducedfromtheexplanans.(b) Irreducible:Theexplanandum cannotbelogicallydeducedfromthe
explanans,regardlessofhowmuchfurtherinformationisprovided.
Implication:Whiletheremaybeinherantlyprobabilisticprocesses,thesecannotbeexplained.
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Ex.1.Anelectronbeamimpingingonapotentialbarrier.• Suppose:Electrone1 tunnelsthrough.
• Noderivationwiththeconclusion"e1 tunneledthroughthebarrier".- TheSchrodingerequationjustpredictstheprobabilitythate1 willtunnelthrough.
• Adeductivechauvinistsays:"Thisisfine,sincetherearenoexplanationsofinherantlyprobabilisticprocesses,likeelectrontunneling."
Maybe ok for strange things like electrons...
Why did e1 tunnel through?
• So:Wecannotconstructaunifyingexplanationofwhye1 tunneledthrough.
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Ex.2.WarfareamongtheYanomami.*
• Importantly:Thereareno factorsthatdeterminewithcertaintytheeventofanattack.
• So:Theeventofanattackisinherentlyprobabilistic.• Thus:Adeductivechauvinistmustclaimthereisnoexplanation forwhytheYanomamiattackedVillageA.
But surely an anthropologist will seek some form of explanation...
*Steel, D. (1998) "Warfare and Western Manufactures: A Case Study of Explanation in Anthropology", Philosophy of Science 65, 649-671.
Moral:Deductivechauvinismisahighpricetopayasaresponsetotheproblemofprobabilisticexplanations.
• Suppose:AnanthropologiststudyingYanomamipeopleofBrazilseeksanexplanationofwhytheYanomamiattackedVillageA.
• Factorscorrelatedwithattacks:- Scarceresources.- Increasedmilitaryadvantage.- Decreasedsocialinfluence.
All prevalent when Western influence is present!
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2.CausalAccount
• Recall:Aflagpolecauses itsshadow,andthuscanexplainit.Itsshadowdoesnotcause theflagpole,andthuscannotexplainit.
CausalAccount:Toexplainsomethingistodescribewhatcausedit.
Why did the glass doors slide open? Because when the customer
approached them, she stepped into the beam of an optical sensor, and this caused a circuit to be broken, which subsequently caused a mechanism to open the door.
Ok.
Salmon,W.(1984)ScientificExplanationandtheCausalStructureoftheWorldLewis,D.(1986)"CausalExplanation"
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TwoCharacteristicsoftheCausalAccount
(a)Local• Acausalexplanationexplainsbyidentifyingalocal cause,asopposedtoaglobal theoreticalframework,oralawthat'ssupposedtoholdeverywhere.
(b)OntologicalClaim:Causalstructureunderlieslawsandtheories• Implication:Allcoveringlawandunifyingexplanationsarecausalexplanations;butnotallcausalexplanationscanbeviewedascoveringlaworunifyingexplanations.
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ThreeProblemsfortheCausalAccount
(i)Problemofthenatureofcausality• Whatdistinguishescausalrelationsfrommerestatisticalcorrelations?
𝐹(𝑡) = 𝑚𝑎(𝑡) = 𝑚𝑑!𝑥(𝑡)𝑑𝑡!
∇ + 𝐸(𝑥, 𝑡) = 4𝜋𝜌 ∇×𝐸(𝑥, 𝑡) =1𝑐𝜕𝐵(𝑥, 𝑡)𝜕𝑡
∇ + 𝐵(𝑥, 𝑡) = 0 ∇×𝐵(𝑥, 𝑡) =1𝑐𝜕𝐸(𝑥, 𝑡)𝜕𝑡
+4𝜋𝐽(𝑥, 𝑡)
𝑐
• Whatroledocausesplayinfundamentaltheories?
90%ofsmokersgotlungcancer.∴Smokingcauseslungcancer.
!!
No parameter for "causation" in equations of motion of fundamental theories in physics...
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Ex.Whycan'tyoufitaleft-handedgloveonyourrighthand?
(ii)Problemofpurelytheoreticalexplanations• Sometheoreticalexplanationsdonotexplicitlyrefertocauses.
Causalexplanation:Thefrictionbetweentheinsidesurfaceofthegloveandyourhandcausesyourhandtostopshortofslidingallthewayintotheglove.
Theoreticalexplanation:Aleft-handedgloveandyourright-handaretopologicallyinequivalentin3-dimEuclideanspace:onecannotbemappedontotheotherbyaseriesof3-dimrigidmotions
Isn't this a scientific explanation?13
(iii)Problemofirreduciblyprobabilisticexplanations• WhatcausedtheYanomamitoattackVillageA?• Whatcausedelectrone1 totunnel?• Toprovidecausalexplanationsofirreduciblyprobabilisticevents,weneedatheoryofprobabilisticcausation.- Evenmoredifficultythanatheoryofsimplecausation!
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