物理主义与人文科学 英文.docx

物理主义与人文科学 英文.docx

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物理主义与人文科学英文

物理主义与人文科学

作者：

大卫.帕皮纽    文章来源：

伦敦大学国王学院    点击数：

824    更新时间：

2008-12-19【哲学在线编辑】

PhysicalismandtheHumanSciences

DavidPapineau

1Introduction

Weareallphysicalistsnow. Itwasnotalwaysso. Ahundredyearsagomosteducatedthinkershadnodoubtthatnon-physicalprocessesoccurredwithinlivingbodiesandintelligentminds. Norwasthisananti-scientificstance:

 thepointwouldhavebeenhappilyagreedbymostpracticingscientistsofthetime. Yetnowadaysanybodywhosaysthatmindsandbodiesinvolvenon-physicalprocessesisregardedasacrank. Thisisaprofoundintellectualshift. InthisessayIwanttoexploreitsmethodologicalimplicationsforthehumansciences. Idonotthinkthatthesehavebeenadequatelyappreciated.

Itissometimessuggestedthatthemodernenthusiasmforphysicalismissomekindofintellectualfad,fannedbythegreatsuccessesofphysicalscienceduringthetwentiethcentury. Butthisunderestimatestheunderpinningsofcontemporaryphysicalism. Thereasonthatscientistsahundredyearsagowerehappytocountenancenon-physicalprocessesisthatnothinginthebasicprinciplesofmechanicsruledthemout. Mechanicstellsushowmaterialbodiesrespondtoforces,butsayslittleaboutwhatforcesexist. Priortothetwentiethcentury,orthodoxscientistscountenancedafarwiderrangeofindependentforcesthanareadmittedtoday:

 theseincludednotonlyseparatechemical,cohesive,andfrictionalforces,butalsospecialvitalandnervousforces. （Considertheterm‘nervousenergy’. Thiswasoriginallyanineteenth-centurytermforthepotentialenergyofthenervousforcefield. Nervousenergywassupposedtobestoredupduringcognitionandthenconvertedintothekineticenergyduringaction.）

Theverdictofthetwentiethcentury,however,hasbeenthattherearenosuchspecialforces. Agreatdealofdetailedexperimentalresearch,includingdetailedphysiologicalresearchintotheinternalworkingoflivingcells,hasfailedtouncoveranyevidenceofmaterialprocessesthatcannotbeaccountedforbyafewfundamentalforces（gravity,electromagnetism,thestrongandweaknuclearforces）. Becauseofthis,specialvitalormentalforcesarenowdiscredited,alongwithchemical,cohesive,andfrictionalforces. Thebasicphysicalforcesarealmostuniversallyregardedasadequatetoaccountforallmaterialprocesses. （Forthehistoryofphysicalism,seePapineau2002,Appendix.）

Wheredoesthisleavethoughts,feelings,relationships,institutionsandtheotherfamiliarhumanentitiesthatformthesubjectmatterofthehumansciences?

 Atfirstsightitmightseemthattheymustbedismissedasillusory. Ifallmaterialeffectsareduetopurelyphysicalinfluences,thendoesn’tthisshowthattheputativecomponentsofhumanrealitydon’tmakeadifferencetoanything?

 Butthiswouldbetooquick. Perhapsthesehumancomponentsarethemselvespartofthephysicalworld,andsoperfectlyabletoinfluencematerialprocesses. Thisisthereductionistoption. Wedon’ttaketheadvancesofphysicalsciencetoshowtherearenothoughtsorinstitutions. Rather,weconcludethatthoughtsandinstitutionsarethemselvesphysicalentities,andsoperfectlyreal. （Comparethewaythatheatwasreducedbythekinetictheoryofgases,ratherthaneliminated. Thekinetictheoryshowedthatallthesupposedeffectsofheatcanbeexplainedbythemotionofmolecules. Butsciencedidn’tconcludethatthereforethereisnoheat. Ratheritsaidthatheatisnothingmorethanmolecularmotion.）

Thisreductionistoptionpromisestosavethesubjectmatterofthehumansciences. Butatthesametimeitthreatenstheirautonomy. Beforetheriseofphysicalism,thehumansciencescouldregardthemselvesasidentifyingmental,behaviouralandsocialpatternsthatwereseparatefromanyphysicalprinciples.  Ofcourse,suchhumanprocessescouldhaveeffectsinthematerialworld,justasDescartes’immaterialmindcouldhaveeffectsonthebody. Butthesehumanprocesseswouldnotthemselvesbepartofthephysicalworld,andsowouldnotbegovernedbyphysicalprinciples. Mental,behaviouralandsocialpatternswouldbequiteindependentofthelawsofphysics.

However,thisautonomyisthreatenedbyphysicalism. AccordingtoErnestNagel’sclassicmodelofreduction（1961）,anypatternsdisplayedatthelevelofa‘reduced’sciencearespecialcasesofthelawsofthe‘reducing’sciences. OnNagel’sconception,reductionrequiresthecategoriesofthereducedsciencetobeidentifiedwithcategoriesofthereducingscience,via‘bridgelaws’. Inconsequence,anyregularitiesofthereducedsciencecaninprincipleberewrittenasregularitiesofthereducingscience. Inthekindofcaseweareinterestedin,thiswouldmeanpsychological,economicandotherhumancategoriesmustbespecifiableinpurelyphysicalterms,andthatanylawsinvolvingthesecategoriesmustbeexpressibleaspurelyphysicallaws.   

Induecourseweshallconsiderfurtherhowfarthisclassicalreductionistmodelreallydoesimpugntheautonomyofthehumansciences. Butfirstweneedtoconsiderwhetherclassicalreductionisreallyforcedonusbyphysicalism. Thiswouldbedeniedbymanyphilosopherstoday. Overthepastfiftyyears,philosophershavedevotedagreatdealofenergytodevelopingvarietiesof‘non-reductivephysicalism’. Theideahereistogoalongwiththebasicphysicalistthoughtthathumanentitiesmustbephysicaliftheyaretomakeadifferenceintherealworld,buttodenythatthespecificrequirementsofclassicNagelianreductionfollow. （Theterminologycanbeabitconfusinghere. Byordinarystandards,‘non-reductivephysicalism’wouldbecountedasaspeciesofreductionism,sinceitrejectsanyontologicalpluralismandcollapsesallreality,includinghumanreality,intothephysicalrealm. ButinthispaperIshalladheretocontemporaryphilosophicaljargon,reserving‘reductionism’forthestrongerrequirementsofNagel’sclassicmodel,andusing‘physicalism’forthemoregeneraldenialofontologicalpluralism.）       

2LawswithoutReduction

Non-reductivephysicalismpromisestorestorethepossibilityofautonomouslawsinthehumansciencesbyallowingforhumanpatternsthatarenotspecialcasesofphysicallaws. TheclassicexplanationofhowthismightworkisFodor’s‘SpecialSciences:

ortheDisunityofScienceasaWorkingHypothesis’（1974）. Fodormadehisanalysisgraphicinwhatmustbethemost-reproduceddiagraminphilosophy.

  S1-----------------------àS2 

↑    ↑   ↑  ↑      ↑        ↑

P1vP2vP3...                  P*1vP*2vP*3... 

↓    ↓   ↑      ↑

-----------------------à

       -------------------------à 

HereS1andS2arespecialkindsandS1->S2isaspeciallaw. FodorgivestheexampleofGresham’sLaw—‘badmoneydrivesoutgood’. Iftherearetwokindsofmoneyincirculation,themoneythatpeopletrustmorewillbehoarded,andthelesstrustedmoneywillbeusedforexchanges. SointhiscaseS1wouldstandforthepresenceoftwokindsofmoney,andS2forthedisappearanceofthegoodmoneyfromcirculation.

Now,ifNagel’sclassicreductionistmodelappliedhere,weshouldbeabletoequateS1withsomespecificphysicalcategoryP,say,andS2withsomespecificphysicalcategoryP*,andthusreducethespecialGresham’sLawS1->S2tothephysicallawP->P*. 

S1-----------------------àS2

↕                                    ↕

P------------------------àP*

ButonFodor’spicturethiswillnolongerbepossible. ThisisbecauseFodordoesnotrequirethatS1orS1beidentifiedastypeswithphysicalcategories. Ratherheholdsthatthesespecialcategorieswillbevariablyrealizedatthephysicallevel,by P1,P2,P3...,andP*1,P*2,P*3 ...respectively. Forexample,insomecasesofGresham’sLawthetwokindsofmoneywillbetwospeciesofcowrieshell,inothercasestheywillbecoinsandnotes,andinyetotherstheywillbevaluesinelectronicregisters. Fodorisaphysicalistallright,inthathesupposesthatineachsuchcaseS1andS2willberealizedbynothingbutphysicalfacts. ButheresistsclassicalreductionbydenyingthatthereisanycommonphysicalnaturetoallthedifferentcasesofS1andS2,andsoafortioridenyingthatthelawS1->S2canbeexpressedinpurelyphysicalterms.

WhenFodortalksof‘variablerealization’,thisshouldbeunderstoodastheconverseofmetaphysicallynecessarydetermination:

 S1isrealizedbyP1ifandonlyifP1metaphysicallynecessitatesS1. ThisiswhatensuresFodorisaphysicalist. NothingmorethanP1isneededtoensureS1. NotevenGodcouldmakesomethingthatisP1withoutS1. Atthesametime,noteverythingthathasS1willhaveP1,orhaveanyotherphysicalkind,sincetherearealwaysotherphysicalways（P2,...）inwhichS1canberealized. ThisiswhyS1isnottype-reducibletoanyphysicalkind,andwhylawsinvolvingS1willnotbeexpressibleinphysicalterminology.

LetuslookabitmorecloselyatthewaytheS1->S2lawisconsistentwithphysicalismwithoutitselfbeingaphysicallaw. Atthephysicallevel,thevariousphysicalPswhichrealizeS1willgenerallygiverisetoP*swhichrealizeS2. Thus,whenS1isrealizedbysomePi,thiswillinstigatephysicalprocessesthatgiverisetoaP*i,whichinturnthendeterminesS2. ThesephysicalprocessesarethusconsonantwiththespeciallawS1->S2.

AccordingtoFodor,suchaPi->P*ilinkneedn’tholdineverysinglecase. SomeofthePisthatrealizeS1willfailtogiverisetoaP*ithatdeterminesS2. Thisiswhy,saysFodor,thelawsofthehumansciencesonlyholdceterisparibus. Therelevantphysica