Interpreting Quantum Theory: A Therapeutic Approach

217 Pages·2015·0.798 MB·English

by  Simon Friederich

NewDirectionsinthePhilosophyofScience
SeriesEditor:StevenFrench,ProfessorofPhilosophyofScience,
UniversityofLeeds,UK
Thephilosophyofscienceisgoingthroughexcitingtimes.Newandproductiverela-
tionshipsarebeingsoughtwiththehistoryofscience. Illuminating andinnovative
comparisonsarebeingdevelopedbetweenthephilosophyofscienceandthephiloso-
phyofart.Theroleofmathematicsinscienceisbeingopeneduptorenewedscrutiny
inthelightoforiginalcasestudies. Thephilosophiesofparticularsciencesareboth
drawingonandfeedingintonewworkinmetaphysics,andtherelationshipsbetween
science,metaphysics,andthephilosophyofscienceingeneralarebeingre-examined
andreconfigured.
TheintentionbehindthisnewseriesfromPalgraveMacmillanistoofferanew,dedi-
catedpublishingforumforthekindofexcitingnewworkinthephilosophyofscience
thatembracesnoveldirectionsandfreshperspectives.
Tothisend,ouraimistopublishbooksthataddressissuesinthephilosophyofscience
in the light of these new developments, including those that attempt to initiate a
dialoguebetweenvariousperspectives, offerconstructiveandinsightfulcritiques, or
bringnewareasofscienceunderphilosophicalscrutiny.
Titlesinclude:
THEAPPLICABILITYOFMATHEMATICSINSCIENCE
IndispensabilityandOntology
SorinBangu
THEPHILOSOPHYOFEPIDEMIOLOGY
AlexBroadbent
PHILOSOPHYOFSTEMCELLBIOLOGY
KnowledgeinFleshandBlood
MelindaFagan
INTERPRETINGQUANTUMTHEORY
ATherapeuticApproach
SimonFriederich
SCIENTIFICENQUIRYANDNATURALKINDS
FromPlanetstoMallards
P.D.Magnus
COMBININGSCIENCEANDMETAPHYSICS
ContemporaryPhysics,ConceptualRevisionandCommonSense
MatteoMorganti
COUNTERFACTUALSANDSCIENTIFICREALISM
MichaelJ.Shaffer
ARESPECIESREAL?
AnEssayontheMetaphysicsofSpecies
MatthewSlater
MODELSASMAKE-BELIEVE
Imagination,FictionandScientificRepresentation
AdamToon
Forthcomingtitlesinclude:
SCIENTIFICMODELSANDREPRESENTATION
GabrieleContessa
NewDirectionsofthePhilosophyofScience
SeriesStandingOrderISBN978–0–230–20210–8(hardcover)
(outsideNorthAmericaonly)
Youcanreceivefuturetitlesinthisseriesastheyarepublishedbyplacingastanding
order.Pleasecontactyourbookselleror,incaseofdifficulty,writetousattheaddress
belowwithyournameandaddress,thetitleoftheseriesandtheISBNquotedabove.
CustomerServicesDepartment,MacmillanDistributionLtd,Houndmills,Basingstoke,
HampshireRG216XS,England
Interpreting Quantum
Theory
A Therapeutic Approach
Simon Friederich
©SimonFriederich2015
Allrightsreserved.Noreproduction,copyortransmissionofthis
publicationmaybemadewithoutwrittenpermission.
Noportionofthispublicationmaybereproduced,copiedortransmitted
savewithwrittenpermissionorinaccordancewiththeprovisionsofthe
Copyright,DesignsandPatentsAct1988,orunderthetermsofanylicence
permittinglimitedcopyingissuedbytheCopyrightLicensingAgency,
SaffronHouse,6–10KirbyStreet,LondonEC1N8TS.
Anypersonwhodoesanyunauthorisedactinrelationtothispublication
maybeliabletocriminalprosecutionandcivilclaimsfordamages.
Theauthorhasassertedhisrighttobeidentifiedastheauthorofthiswork
inaccordancewiththeCopyright,DesignsandPatentsAct1988.
Firstpublished2015by
PALGRAVEMACMILLAN
PalgraveMacmillanintheUKisanimprintofMacmillanPublishersLimited,
registeredinEngland,companynumber785998,ofHoundmills,Basingstoke,
HampshireRG216XS.
PalgraveMacmillanintheUSisadivisionofStMartin’sPressLLC,
175FifthAvenue,NewYork,NY10010.
PalgraveMacmillanistheglobalacademicimprintoftheabovecompanies
andhascompaniesandrepresentativesthroughouttheworld.
Palgrave®andMacmillan®areregisteredtrademarksintheUnitedStates,
theUnitedKingdom,Europeandothercountries.
ISBN:978–1–137–44714–2
Thisbookisprintedonpapersuitableforrecyclingandmadefromfully
managedandsustainedforestsources.Logging,pulpingandmanufacturing
processesareexpectedtoconformtotheenvironmentalregulationsofthe
countryoforigin.
AcataloguerecordforthisbookisavailablefromtheBritishLibrary.
AcatalogrecordforthisbookisavailablefromtheLibraryofCongress.
To Sibylla, Alma, and Lydia

Contents
SeriesEditor’sForeword x
Preface xii
Part I IntroductionandBackground
1 Introduction 3
1.1 Quantumfoundations 3
1.2 Theideaofatherapeuticapproach 6
1.3 Outlineofthiswork 8
2 SketchoftheFormalism 13
2.1 TheHilbertspaceformalism 13
2.2 Measurementandcollapse 18
2.3 Many-componentsystemsandentanglement 21
3 InterpretationsasSolutionstotheMeasurementProblem 26
3.1 Expositionoftheproblem 26
3.1.1 Maudlin’sformulation 26
3.1.2 Afallacioussolution 29
3.2 Additionalparameters 31
3.2.1 Pilotwavetheory 31
3.2.2 Alternatives:modalinterpretations 37
3.3 Schro¨dingertime-evolutionnotuniversal? 38
3.3.1 FromWignertoPenrose 39
3.3.2 TheGRWmodel 40
3.4 Nodeterminateoutcomes 41
3.4.1 Definingbranches 42
3.4.2 Howdoprobabilitiesfitintothepicture? 44
Part II TheRule Perspective
4 MotivatingaTherapeuticApproach 49
4.1 Absenceofthefoundationalproblems
inpractice 49
4.2 Philosophyastherapy 50
4.3 Quantumstatesasnon-descriptive 53
4.3.1 Dissolvingthemeasurementproblem 54
vii
viii Contents
4.3.2 Collapseasupdate 55
4.3.3 Typesofepistemicaccounts 56
4.4 Space-timestructureandcollapse 58
5 InSearchofaViableEpistemicAccount 61
5.1 Knowledgeofprobabilitiesversusprobabilitiesas
degreesofbelief 61
5.2 QuantumBayesianism 62
5.2.1 Probabilitiesassubjective 62
5.2.2 Valuesofobservablesassubjective? 64
5.3 Objectivityofobservablesmeasuredinanepistemic
accountofstates 68
5.4 Constitutiverules 71
6 QuantumProbabilities:WhatAreThey? 75
6.1 Probabilitiesofwhat? 75
6.2 Probabilitiesofwhatkind? 79
6.2.1 Relativefrequencies? 80
6.2.2 Propensities? 82
6.2.3 Objectiveprobabilitiesasconstraintson
rationalcredences 84
6.3 Objectionstothisinterpretationofprobabilities 85
6.3.1 Themeans/endsobjection 85
6.3.2 ThequantumBayesianMoore’sparadox 87
Part III Objections
7 CopenhagenReloaded? 95
7.1 Bohrand‘classicallanguage’ 96
7.2 Heisenbergandtheepistemicconceptionof
quantumstates 99
7.2.1 Heisenbergonpureversusmixedstates 99
7.2.2 Heisenbergonquantumprobabilitiesas
‘objectivetendencies’ 102
8 TheChargeofAnthropocentrism 105
8.1 Bell’scriticism 105
8.2 Anthropocentricnotionsandvaluedeterminateness 108
9 ReductionandExplanation 113
9.1 Themicro/macrodivide 113
9.2 Explanationwithoutonticquantumstates 115
Contents ix
Part IV Non-locality,Quantum Field
Theory,andReality
10 Non-localityReconsidered 125
10.1 Quantumtheoryandspecialrelativity–again 125
10.2 Formulatinglocalcausality 127
10.2.1 Causationandcounterfactuals 129
10.2.2 Localcausalityprobabilistically 132
10.3 ThePrincipalPrincipleandadmissibleevidence 136
10.4 Intuitiveprobabilisticlocalcausalityinthelanguage
ofthePrincipalPrinciple 139
10.5 Quantumtheory,localcausality,andthePrincipal
Principle 141
10.6 Buthowdoesnatureperformthetrick? 143
11 ALookatQuantumFieldTheory 146
11.1 Lagrangianversusalgebraicquantum
fieldtheory 146
11.2 Basicsofthealgebraicapproach 147
11.3 ‘Pristine’interpretations 148
11.4 TheRulePerspectiveandunpristineinterpretations 150
11.5 Thecaseforanunpristineinterpretation 152
12 QuantumTheoryand‘Reality’ 157
12.1 Instrumentalism? 158
12.2 Sharpvaluesforallobservables? 161
12.3 Conclusion 166
Appendices
AppendixA SketchofBell’sTheorem 168
AppendixB TheKochen–SpeckerTheoreminaNutshell 172
AppendixC ThePusey–Barrett–Rudolph(PBR)Theorem–AShort
Introduction 175
Notes 178
Bibliography 187
Index 197