LOGICAL POSITIVISMEditedbyA.J.AYER TheFree Press,NewYork -iiiCopyright1959byTheFreePress,aCorporation PrintedintheUnitedStatesofAmerica Allrightsreserved.Nopartofthisbookmaybereproducedor utilizedinanyformorbyanymeans,electronicormechanical, photocopying,recording,orbyanyinformationstorageand retrievalsystem,withoutpermissioninwritingfromthePublisher. Collier-MacmillanCanada,Ltd.,Toronto,Ontario LibraryofCongressCatalogCardNumber:58-6467 SecondprintingJuly1966 -iv-

PrefaceLogicalPositivismisthesecondinaseriesofbookswhichwillmake availabletothegeneralpublicsomeofthemostinterestingworkof philosophersofverydiverseviewpoints.Eachvolumewilldealwith oneor,insomecases,withtwo,philosophical"schools"or "movements."Itisfortunatethatphilosophersarerarelyunitedby thekindofcommonpurposewhichinspirespoliticalorreligious "movements."Nevertheless,itisfrequentlyhelpfultoconsiderthe workofdifferentwritersaccordingtothesimilaritiesintheiraim andcontentandthisisthepolicywhichhasbeenadoptedin designingtheLibraryofPhilosophicalMovements. Thisvolumepresents,forthefirsttimeinEnglish,manyofthe mostinfluentialpapersbyleadingmembersoftheViennaCircle. Theseandotherarticlescontainauthoritativeexpositionsofthe doctrinesmostcommonlyassociatedwithlogicalpositivism. However,forreasonsexplainedbyProfessorAyerinhis introduction,severalpieceswhichcannotberegardedas expositionsordefensesoflogicalpositivismhavealsobeen included.Thescopeofthebibliography,too,isbroaderthanthe titleofthebookwouldsuggest.Novolumedealingwithotherforms ofanalyticphilosophyiscontemplatedinthisseriesanditwas therefore thoughtdesirabletolistthemostimportantbooksand

articlesdealingwithalltypesofanalyticphilosophyandnotonly withlogicalpositivism. Iwishtoexpressmygratitudetoallthetranslatorswhogenerously contributedtheirlabor,toMarvinZimmerman,JamesBayley,Irving Saltzmann,andanumberofmystudentsforhelpingtocompilethe bibliography,andtoLeonSatinoff,MaxwellGrober,andJos Huerta-Jourdaforpreparingtheindex.Specialthanksaredueto ProfessorsCarnapandHempelforsupplyingnoteswhichindicate theirpresentpositionontheissuesdealtwithintheirpapers. ProfessorCarnapwasalsokindenoughtoassistinthetranslation ofhisownarticles. PAULEDWARDS -v[Thispageintentionallyleftblank.] -vi-

Contents

PREFACE EDITOR'SINTRODUCTION

LogicalAtomism

v 3 31

Philosophy,MetaphysicsandMeaningMoritzSchlick"THETURNINGPOINTIN PHILOSOPHY" RudolfCarnap"THEELIMINATION OF METAPHYSICSTHROUGHLOGICAL ANALYSISOFLANGUAGE" MoritzSchlick"POSITIVISMANDREALISM" CarlG.Hempel"THEEMPIRICIST CRITERION OFMEANING" RudolfCarnap"THEOLDANDTHENEW LOGIC" HansHahn"LOGIC,MATHEMATICSAND KNOWLEDGEOFNATURE" -vii-

BertrandRussell"LOGICALATOMISM"

53 60 82 108

LogicandMathematics

133 147

KnowledgeandTruth

RudolfCarnap"PSYCHOLOGYINPHYSICAL LANGUAGE" OttoNeurath"PROTOCOLSENTENCES" MoritzSchlick"THEFOUNDATIONOF KNOWLEDGE"

165 199 209

EthicsandSociology

A.J.Ayer"VERIFICATION AND EXPERIENCE" MoritzSchlick"WHATISTHEAIMOF ETHICS?" C.L.Stevenson"THEEMOTIVEMEANINGOF ETHICALTERMS" OttoNeurath"SOCIOLOGYAND PHYSICALISM"

228

247 264 282 321 327 345 381 447

AnalyticalPhilosophy

FrankD.Ramsey"PHILOSOPHY" GilbertRyle "PHILOSOPHICALARGUMENTS" FriedrichWaismann"HOWISEE PHILOSOPHY" BIBLIOGRAPHYOFLOGICALPOSITIVISM INDEX -viii-

LOGICALPOSITIVISM-1[Thispageintentionallyleftblank.] -2-

Editor'sIntroduction

I.HISTORYOFTHELOGICALPOSITIVIST MOVEMENTTHETERM"LogicalPositivism"wascoinedsomethirtyyearsagoto characterize thestandpointofagroupofphilosophers,scientists andmathematicianswhogavethemselvesthenameoftheVienna Circle.Sincethattimeitsreferencehasbeenextendedtocover otherformsofanalyticalphilosophysothatdisciplesofBertrand Russell,G.E.MooreorLudwigWittgensteinatCambridge,or membersofthecontemporaryOxfordmovementoflinguistic analysismayalsofindthemselvesdescribedaslogicalpositivists. Thiswiderusageisespeciallyfavoredbythosewhoarehostileto thewholemoderndevelopmentofphilosophyasananalytical ratherthanaspeculativeenquiry.Theywishtotaralltheir adversarieswithasinglebrush.Thisisirritatingtotheanalysts themselveswhoarerathermoresensitivetotheirdifferencesthey wouldpreferthattheappellationof"logicalpositivist"bereserved forthosewhosharethespecialoutlookoftheViennaCircle.In compilingthisanthology,Ihavenotbeenquitesostrict.Ihave

drawnmainlyonthewritingsofthemembersoftheViennaCircle, orofthosewhostandclosesttothem,butIhavealsoincluded severalpieceswhichfalloutsidethisrange.Theyareall,insome sense,analyticalbutthescopeofwhatIregardasanalytical philosophyiswide.Itallowsforseriousdisagreement,notonlyover technicalniceties,butonmajorpointsofdoctrine,includingthe methodandpurposeofanalysisitself. TheViennaCirclecameintobeingintheearly1920'swhenMoritz Schlick,aroundwhomitcentered,arrivedfromKieltobecome professorofphilosophyattheUniversityofVienna.Onthe philosophicalsideitsleadingmembers,besidesSchlickhimself, wereRudolfCarnap,OttoNeurath,HerbertFeigl,Friedrich Waismann,EdgarZilselandVictorKraftonthescientificand mathematicalside,PhilippFrank,KarlMenger,KurtGdelandHans Hahn.Atthebeginning,itwasmoreofaclubthananorganized movement.Findingthattheyhadacommoninterestin,anda -3similarapproachto,acertainsetofproblems,itsmembersmet regularlytodiscussthem.Thesemeetingscontinuedthroughoutthe lifeoftheCirclebuttheycametobesupplementedbyother activitieswhichtransformedtheclubintosomethingmorenearly resemblingapoliticalparty.Thisprocessbeganin1929withthe publicationofamanifestoentitled"Wissenschaftliche Weltauffassung,DerWienerKreis"--The ViennaCircleItsScientific Outlook-whichgaveabriefaccountofthephilosophicalpositionof thegroupandareviewoftheproblemsinthephilosophyof mathematicsandofthephysicalandsocialsciencesthattheywere chieflyconcernedtosolve.Thispamphlet,whichwaswrittenby Carnap,NeurathandHahn,isalsoofinterestasshowinghowthe Circle situateditselfinthehistoryofphilosophy.Afterclaimingthat theywere developingaViennesetraditionwhichhadfloweredat theendofthenineteenthcenturyintheworkofsuchmenasthe physicistsErnstMachandLudwigBoltzmann,and,inspiteofhis theologicalinterests,thephilosopherFranzBrentano,theauthors setoutalistofthosewhomtheyregardedastheirmain precursors.AsempiricistsandpositiviststheynamedHume,the philosophersoftheenlightenment,Comte,Mill,Avenariusand Machasphilosophersofscience,Helmholtz,Riemann,Mach, Poincar,Enriques,Duhem,BoltzmannandEinsteinaspureand appliedlogicians,Leibniz,Peano,Frege,Schrder,Russell, WhiteheadandWittgensteinasaxiomatists,Pasch,Peano,Vailati, PieriandHilbertandasmoralistsandsociologistsofapositivistic temper,Epicurus,Hume,Bentham,Mill,Comte,Spencer, Feuerbach,Marx,Mller-Lyer,Popper-LynkeusandtheelderCarl Menger.Thislistissurprisinglycomprehensive,butitmustbe rememberedthatinmostcasesitisonlyaquestionofaspecial aspectoftheauthor'sworks.ThusLeibnizisincludedforhislogic, notforhismetaphysicsKarlMarxisincludedneitherforhislogic norhismetaphysicsbutforhisscientificapproachtohistory.Ifwe excludecontemporariesfromthelist,thosewhostandclosestto

theViennaCircleintheirgeneraloutlookareHumeandMach.Itis indeedremarkable howmuchofthedoctrinethatisnowthoughtto beespeciallycharacteristicoflogicalpositivismwasalreadystated, oratleastforeshadowed,byHume. Amongcontemporaries,Einstein,Russell,andWittgensteinare singledoutbytheauthorsofthepamphletfortheirkinshiptothe ViennaCircleandtheextentoftheirinfluenceuponit.Wittgenstein, indeed,stoodtotheViennaCircleinaspecialrelation.Havingbeen apupilofRussell'satCambridge beforethefirstworldwarhe returnedtoViennaandwastherewhenhisLogischPhilosophischeAbhandlung -4Abhandlungwaspublishedin1921.Thisfamousbook,whichis betterknownasTractatusLogico-Philosophicus,thetitlegiventoits Englishtranslation,hadanenormouseffectuponthepositivist movement,bothinViennaandelsewhere.Itwouldnotbequite correcttosaythattheViennaCircledrewitsinspirationfromit. Schlickhimself,inhisbookonthetheoryofknowledge,Allgemeine Erkenntnislehre ,ofwhichthefirsteditionappearedin1918,had independentlyarrivedatasimilarconceptionofphilosophyand thereisahintofmysticismintheTractatuswhichsomemembers oftheCircle,especiallyNeurath,founddisquietingbutasawhole theyacceptedit,anditstoodoutasthemostpowerfuland exciting,thoughnotindeedthemostlucid,expositionoftheirpoint ofview.WittgensteindidnotofficiallyadheretotheCirclebuthe maintainedclosepersonalrelationsatleastwithSchlickand Waismannwhomhecontinuedtoinfluenceevenafterhisdeparture forCambridgein1929.InCambridge,wherehetaughtuntil1947, fouryearsbeforehisdeath,heexercisedanalmostdespoticsway overhispupils,andthoughhepublishednothingduringtheseyears exceptoneshortarticlehisinfluencewasstrongly,ifinmostcases indirectly,feltbyalmostalltheyoungergenerationofBritish philosophers.Hehimselfmodifiedtherigorsofhisearlypositivism toanextentthatcanbemeasuredbycomparingtheTractatuswith hisposthumouslypublishedPhilosophicalInvestigationsanditisto hisinfluence,combinedwiththatofMoore,thatonemaylargely attributethepreoccupationofcontemporaryBritishphilosophers withtheeverydayusesoflanguage,andtheirtendencytodealwith philosophicalquestionsinanunsystematic,illustrativeway,in contrasttothemorerigorouswould-be scientificmethodwhichwas favoredbytheViennaCircle.Thisisonereasonwhytheyarenot happytobedescribedasLogicalPositivists.ButIshallhavemore tosayaboutthesealternative conceptionsofanalysislateron. Itwasin1929alsothattheViennaCircleorganizeditsfirst internationalcongress.ItwasheldatPragueandwasfollowedat intervalsthroughoutthethirtiesbyfurthercongressesat Knigsberg,Copenhagen,Prague,ParisandCambridge.These meetingsfurtheredtheambitionoftheCircletodevelopLogical Positivismasaninternationalmovement.Ithadformedanearly

alliancewiththeso-calledBerlinschoolofwhichHansReichenbach, RichardvonMises,KurtGrellingandatalaterdateCarlHempel weretheleadingmembers.Thecongresseshelpedittomake contactalsowithScandinavianphilosopherssuchasEinoKaila,Arne Naess,ke Petzll,JoergenJoergensen,andtheUppsalaschoolof empiricists,withtheDutch -5grouparoundthephilosopherMannourywhopursuedwhatthey calledthestudyofSignifics,withtheMnstergroupoflogicians underHeinrichScholtz,withAmericansympathizerssuchasNagel, CharlesMorrisandQuine,andwithBritishanalystsofvarious shadesofopinion,suchasSusanStebbing,GilbertRyle,R.B. Braithwaite,JohnWisdomandmyself.ThebrilliantCambridge philosopherF.P.Ramseywasmarkedasanadherent,buthedied in1930attheearlyageof26.Analliancewasalsoformedwiththe veryimportantPolishgroupsofphilosophersandlogicians,ofwhom Lucasiewicz,Lesnievsky,Chwistek,Kotarbinski,Ajduciewiczand Tarskiwere perhapsthemostprominent.TheinfluenceofTarski's work,particularlyonCarnap,wasnoticeablystrong. ThemissionaryspiritoftheCirclefoundafurtheroutletinits publications.In1930ittookoverajournalcalledAnnalender Philosophie,renameditErkenntnisandmadeit,underthe editorshipofCarnapandReichenbach,theprincipalorganofthe positivistmovement.Inthefollowingyearstherealsoappeareda seriesofmonographswiththecollectivetitleof Einheitswissenschaft--UnifiedScience--andaseriesofbooks,under thegeneraleditorshipofSchlickandPhilippFrank,withthe collectivetitleofSchriftenzurWissenschaftlicheWeltauffassung. Schlickhimselfcontributedtoitabookonethics,ofwhichthefirst chapterisincludedinthisvolume,andFrankabookonthelawof causalityanditslimitations.Amongtheothervolumestoappearin itwere animportantbookbyCarnaponthelogicalsyntaxof language,towhichIshallhaveoccasiontoreferagain,abookon sociologybyNeurathwithsomewhatMarxistleanings,andKarl Popper'sfamousLogikderForschungwhichwasdevotedtothe philosophyofscience.Popperwasnotinfactamemberofthe Circle andwouldatnotimehavewishedtobeclassedasa positivist,buttheaffinitiesbetweenhimandthepositivistswhom hecriticizedappearmorestrikingthanthedivergencies.Inany casethemembersoftheCircledidnotinallpointsagreeamong themselves. Thoughthelogicalpositivistmovementgatheredstrength throughoutthethirties,theViennaCircleitselfwasintheprocessof dissolution.By1933,whenIattendeditsmeetings,Carnapand FrankhadacceptedchairsattheUniversityofPragueandthe discussionswere chieflycarriedonbySchlick,Neurath,Waismann andHahn.ButHahndiedin1934andtwoyearslaterSchlickwas murdered,attheageof54,byadementedstudentwhoshothim ashewasenteringtheUniversity.Thehostiletoneoftheobituaries

whichwere devotedtoSchlickinthegovernmentalpress,implying almostthatlogical -6positivistsdeservedtobemurderedbytheirpupils,foreshadowed thetroubleswhichwere soontofallupontheCircle.Exceptfor Neurath,whohadparticipatedintherevolutionarySpartacist GovernmentinMunichattheendofthefirstworldwar,its membershadnotbeenconspicuouslyactiveinpolitics,buttheir criticalandscientifictempermadethemsuspecttotheright-wing clericalgovernmentsofDolfussandSchuschniggandstillmoreso totheNazis.Themajorityofthemwereforcedintoexile.The adventofNazismwasfatalalsototheBerlinschool,andthePolish groupswere disruptedbythewar.Neurath,whohadtakenrefuge inHolland,madeavaliantattempttokeepthemovementgoing. ThetitleofErkenntniswaschangedtoTheJournalofUnified ScienceanditsplaceofpublicationtotheHague.Arrangements weremadeforthepublicationbytheUniversityofChicago,where Carnapwasestablished,ofaseriesofbrochuresambitiously entitledtheInternationalEncyclopediaofUnifiedScience.Further congresseswere planned.Butwiththeoutbreakofwarand Neurath'sdeathinEnglandsomeyearslater,themovementlostits cohesion.Mostofthevolumeswhichweredesignedtoconstitute theEncyclopediahaveinfactappeared,buttheJournalofUnified Scienceverysoonceasedpublicationandhasnotbeenrevived. BesidesCarnap,Feigl,Gdel,Frank,HempelandTarskiarestillat universitiesintheUnitedStates,andWaismannandPopperat universitiesinEngland.ScholtzhasremainedatMnsterand KotarbinskiandAjduciewiczinPolandandVictorKraftresumedhis chairofphilosophyattheUniversityofVienna.But,howevermuch influencethesephilosophersmayexertindividually,theydonot constituteaschool.Inthissense,thelogicalpositivistmovement hasbeenbrokenup. Neverthelessitstraditionhasbeencontinued,especiallyinEngland, ScandinaviaandtheUnitedStates.InScandinavia,Kailahasbeen joinedatHelsinkibyVonWright,apupilofWittgenstein'swho succeededhimforatimeasprofessorofphilosophyatCambridge, theUppsalaschoolstillflourishes,underthedirectionofHedenius, SegerstedtandMarc-Wogau,withsupportfromthelogician WedberginStockholm,andArne NaessinOslopursueshis sociologicalresearchesintothecurrentusesoflanguage.Petzll continuedtoteachatLunduntilhisdeathin1957andJoergensenis stillteachinginCopenhagen,thoughhispositivismhasbeen modifiedbyaninjectionofMarxism.IntheUnitedStatesanumber ofphilosopherslikeQuine,NagelandNelsonGoodmanconduct logicalanalysisinasystematicscientificspiritthatisprobablycloser totheoriginalidealoftheViennaCirclethananythingthatisnow tobemetwithelse-7-

where.InthisconnectionNelsonGoodman'sbookTheStructure of Appearance (1951)andQuine'scollectionofessaysFromaLogical PointofView(1953)areespeciallynotable.Theiractiveinterestin symboliclogicbringsQuineandGoodmanalsointorelationwith Tarski,Gdel,Churchandothermembersoftheimportant contemporarygroupofAmericanlogicians.Thesameoutlookis maintainedbyCarnapandhispupils,notablyBarHillel,whoisnow teachingattheUniversityofJerusalem,andbyFeiglandHempel. OtherphilosophersintheUnitedStatessuchasNormanMalcolm, MaxBlack,MorrisLazerowitzandC.L.Stevensonowemoretothe influenceofG.E.MooreorthelaterWittgenstein,andconsequently displayanapproachtophilosophicalquestionswhichiscloserto thatofthecontemporaryBritishschools. InspiteoftheexampleofBertrandRussell,thereisnotnow amongBritishphilosophersthesameinterestinformallogic,or beliefintheutilityofsymbolictechniquesforclarifyingphilosophical issues,asistobefoundintheUnitedStates.Neitheristherethe samedesiretoconnectphilosophywithscience.MyownLanguage, TruthandLogic,ofwhichthefirsteditionappearedin1936,did somethingtopopularizewhatmaybecalledtheclassicalpositionof theViennaCirclebutsincethewartheprevailingtendencyin Englandhasbeentoreplacethisuncompromisingpositivismwithits blanketrejectionofmetaphysics,itsrespectforscientificmethod, itsassumptionthatinsofarasphilosophicalproblemsaregenuine atalltheycanbedefinitelysolvedbylogicalanalysis,byan approachtophilosophywhichisempiricalinthepoliticalsense,the senseinwhichBurke wasachampionofempiricism. Generalizationsaredistrusted,particularexamplesaremultiplied andcarefullydissected.Anattemptismadetoilluminateevery facetofaproblemratherthantohammerorcarveoutasolution, commonsensereignsasaconstitutional,ifnotanabsolute, monarch,philosophicaltheoriesareputtothetouchstoneofthe wayinwhichwordsareactuallyused.Themetaphysicianistreated nolongerasacriminalbutasapatient:theremaybegood reasonswhyhesaysthestrangethingsthathedoes.This therapeutictechnique,asithasbeencalled,iswelldisplayedinthe workofJohnWisdom,nowaprofessoratCambridge,whose collectedvolumesofarticles,OtherMindsandPhilosophyand Psycho-Analysis,appearedin1952and1953.Amorerobustform oftherapyispractisedbyGilbertRyle,professorofmetaphysicsat Oxford,whoseConceptofMind(1949),withitsattackonthe Cartesianmythof"theghostinthemachine,"hashadaverygreat -8influence.RyleshareswithWisdomataste,andagift,foranalogy andmetaphor,andafondnessforpilingupexamples,butheisless afraidofageneralization,lesstolerantofdeparturesfromordinary usage,moredirectinhismethodthananypresent-day Wittgensteinian,andmorereadytoassumethataphilosophical problemhasacorrectsolution.Whatisnowsometimescalledthe Oxfordschool,whichtakesitstonefromJ.L.Austinmorethan

fromRyle,carriesitsinterestintheordinaryuseoflanguagetoa pointwhereitmaybethoughtthatphilosophicalanalysishasgiven waytothestudyofphilology.Butthistendencyisnotall-prevailing. TheworkofsuchphilosophersasStuartHampshire,P.F.Strawson andDavidPearsshowsthatevenwithintheframeworkofthe Oxfordmannerthereisstillroomforafairlywidelatitudeof approach.Thechargeofscholasticismwhichisbroughtagainst "Oxfordphilosophy"isnotentirelybaselessbutitisnotatruly warrantedindictment. Atthepresenttime,thephilosophicalworldiscuriouslydivided.If positivismbetakeninitswidestsense,thesenseinwhichit embracesallshadesofanalytical,linguistic,orradicallyempirical philosophy,itisdominantinEnglandandinScandinavia,and commandsconsiderableallegianceinHollandandBelgium,in AustraliaandintheUnitedStates.Elsewhere,itmakeshardlyany showingatall.Theoretically,itisnotinallrespectsatoddswith Marxism:thetwoatleasthavecertainenemiesincommon:butit cannotflourishunderCommunistregimes,sinceLenin'sMaterialism andEmpirioCriticism,anattackonMachandhisfollowerswhich appearedin1905,declaresittobeaformofbourgeoisidealism.In othercountriesagain,onefindsphilosopherssubscribingtoneoThomismortoneo-Kantianismortoneo-Hegelianismorto ExistentialismorwhateverformofGermanmetaphysicsmaybein fashion.TheascendancyofGermanyoverFranceinthisrespectis especiallyremarkable.Conversely,inEnglish-speakingcountries therehasbeenthroughoutthepresentcenturyanalmostcomplete disregardofthecurrentextravaganciesofGermanspeculative thought.Suchnationaldivisionsareindeedregrettable.Theydonot occurtoanythinglikethesameextentinotherbranchesof learning.Itisespeciallycharacteristicofphilosophersthattheytend todisagreenotmerelyaboutthesolutionofcertainproblemsbut abouttheverynatureoftheirsubjectandthemethodsbywhichit istobepursued.Like othersbeforethem,theViennaCircle believedthatthiscouldandshouldberemedied.Theythoughtthat theyhadsucceeded,whereKanthadfailed,infindingaway"toset philosophyuponthesurepathofascience."Thisend -9hasnotbeenattained:itmay,indeed,beunattainable.Allthe same,therecanbeprogressinphilosophyandinonewayand anotherthepositivistmovementisachievingit.

II.THEATTACKONMETAPHYSICS"Whenwerunoverlibraries,persuadedoftheseprinciples,what havocmustwemake?Ifwetakeinourhandanyvolumeof divinityorschoolmetaphysics,forinstanceletusask,Doesit containanyabstractreasoningconcerningquantityornumber?No. Doesitcontainanyexperimentalreasoningconcerningmatterof factandexistence?No.Commititthentotheflames:foritcan containnothingbutsophistryandillusion."Thisquotationistaken

fromDavidHume'sEnquiryConcerningHumanUnderstanding.Itis anexcellentstatementofthepositivist'sposition.Inthecaseofthe logicalpositivists,theepithet"logical"wasaddedbecausethey wishedtoannexthediscoveriesofmodernlogictheybelieved,in particular,thatthelogicalsymbolismwhichhadbeendevelopedby Frege,PeanoandRussellwouldbeserviceabletothem.Buttheir generaloutlookwasverymuchthesameasHume's.Like him,they dividedsignificantpropositionsintotwoclassesformalpropositions, likethoseoflogicorpuremathematics,whichtheyheldtobe tautological,inasensethatIshallpresentlyexplain,andfactual propositions,ofwhichitwasrequiredthattheyshouldbe empiricallyverifiable.Theseclassesweresupposedtobe exhaustive:sothatifasentencesucceededneitherinexpressing somethingthatwasformallytrueorfalsenorinexpressing somethingthatcouldbeempiricallytested,theviewtakenwasthat itdidnotexpressanypropositionatall.Itmighthaveemotive meaningbutitwasliterallynonsensical.Agreatdealof philosophicaltalkwasheldtofallintothiscategory:talkaboutthe absolute,ortranscendententities,orsubstance,orthedestinyof man.Suchutterancesweresaidtobemetaphysicalandthe conclusiondrawnwasthatifphilosophywastoconstituteagenuine branchofknowledgeitmustemancipateitselffrommetaphysics. TheViennesepositivistsdidnotgosofarastosaythatall metaphysicalworksdeservedtobecommittedtotheflames:they allowed,somewhatperfunctorily,thatsuchwritingmighthave poeticmeritoreventhatitmightexpressanexcitingorinteresting attitudetolife.Theirpointwasthatevensoitdidnotstate anythingthatwaseithertrueorfalseandconsequentlythatitcould contributenothingtotheincreaseofknowledge.Metaphysical utteranceswere condemnednotforbeingemotive,whichcould hardlybeconsideredasobjectionableinitself,butforpretendingto becognitive,formasqueradingassomething -10thattheywere not.Attacksonmetaphysicsoccurfairlyfrequentlyin thehistoryofphilosophy.IhavequotedHumeandImightalso havequotedKantwhomaintainedthatthehumanunderstanding lostitselfincontradictionswhenitventuredbeyondtheboundsof possibleexperience.Theoriginalityofthelogicalpositivistslayin theirmakingtheimpossibilityofmetaphysicsdependnotuponthe natureofwhatcouldbeknownbutuponthenatureofwhatcould besaid.Theirchargeagainstthemetaphysicianwasthathebreaks theruleswhichanyutterancemustsatisfyifitistobeliterally significant. Attheoutset,theirformulationoftheseruleswaslinkedwitha conceptionoflanguagewhichWittgenstein,whoinheriteditfrom Russell,madefullyexplicitinhisTractatus.Theunderlying assumptionisthattherearestatementswhichareelementaryin thesensethat,iftheyaretrue,theycorrespondtoabsolutely simplefacts.Itmaybethatthelanguagewhichweactuallyuse doesnotcontainthemeansofexpressingthesestatements:the

statementswhichitcanserve toexpressmaynoneofthembe entirelyelementarybutthesemorecomplexstatementsmuststill restuponafoundationofelementarystatements,evenifthe foundationbehidden.Theyaresignificantonlyinsofarastheysay whatwouldbesaidbyaffirmingcertainelementarystatementsand denyingcertainothers,thatis,onlyinsofarastheygiveatrueor falsepictureoftheultimate"atomic"facts.Theycan,therefore,be representedasbeingconstructedoutofelementarystatementsby thelogicaloperationsofconjunctionandnegation,insuchaway thattheirtruthorfalsehoodisentirelydependentonthetruthor falsehoodoftheelementarystatementsinquestion.Thus, assumingpandqtobeelementarystatements,the"molecular" statement"porq"istakentobeequivalentto"not(not-pandnotq)"andthismeansthatitisfalseifbothpandqarefalse,but trueinthethreeremainingcases,namelythatinwhichpandqare bothtrue,thatinwhichpistrueandqfalse,andthatinwhichpis falseandqtrue.Ingeneral,givennelementarystatements,where nisanyfinitenumber,thereare2npossibledistributionsoftruth andfalsehoodamongthem:andthemeaningofthemorecomplex statementswhichcanbeconstructedoutofthemisconstitutedby theselectionoftruthdistributionswithwhichtheyagreeor disagree. Asarule,itwillbefoundthatastatementagreeswithsometruth distributionsanddisagreeswithothers:amongthepossiblestates ofaffairswithwhichitisconcerned,somewouldmakeittrue,and otherswouldmakeitfalse.Thereare,however,twoextreme casesthatinwhichastatementagreeswitheverytruthdistribution and -11thatinwhichitagreeswithnone.Intheformercaseitistruein anycircumstanceswhatsoever,andinthelattercasefalse. AccordingtoWittgenstein,thesetwoextremesarethoseof tautologyandcontradiction.Onthisview,allthetruthsoflogicare tautologiesandifRussellandWhiteheadsucceededintheir attempttoshowthatmathematicsisreducibletologic,soarethe truthsofmathematics.Wittgensteinhimselfdidnotallowthat mathematicalstatementswere tautologieshesaidthattheywere identities:butapartfromtechnicalconsiderations,thiscomesto muchthesamething.Thepointisthatneithersayanythingabout theworld.Theonlywayinwhichtheycanaddtoourknowledge is byenablingustoderiveonestatementfromanother:thatis,by bringingouttheimplicationsofwhat,inasense,weknowalready. Tautologiessaynothingbecauseoftheirexcessivemodesty:since theyagreewitheverypossiblestateofaffairs,theymakenoclaim uponthefacts.Thus,Iobtainsomeinformation,whethertrueor false,aboutthehabitsoflionsifIamtoldthattheyare carnivorous,andequallyifIamtoldthattheyarenotbuttotell methattheyareeithercarnivorousornotistotellmenothing aboutthematall.Similarly,contradictionssaynothingbecauseof

theirexcessive cantankerousnesstodisagreewitheverypossible stateofaffairsisagaintobedisqualifiedfromgivingany information.Ilearnnothing,notevenanythingfalse,aboutthe habitsoflionsifIamtoldthattheyareandarenotcarnivorous. Onthisinterpretation,tautologiesandcontradictionsare degeneratecasesoffactualstatements.Metaphysicalassertions,on theotherhand,aremeaninglessbecausetheybearnorelationto fact.Theyarenotconstructedoutofelementarystatementsinany wayatall. SinceWittgensteindidnotsaywhathetookhiselementary statementstobe,hedidnotmakeitquiteclearatwhatpointone isdeemedtoenterintometaphysics.Itwouldseem,however,that anyattempttocharacterize realityasawhole,anysuchassertion asthattheUniverse isspiritual,orthateverythinghappensforthe bestinthebestofallpossibleworlds,mustforhimbe metaphysicalforsuchassertionsdonotdiscriminatebetween possiblestatesofaffairswithintheworld--nomatterwhathappens, itistobecharacterizedasspiritual,orregardedashappeningfor thebest--fromwhichitfollowsthattheyarenotfactual.Neitherdo theyseemtobeconstructedoutoffactualstatementsintheway thattautologiesare.Andeveniftheyweretheywouldstillsay nothing. WhatevermayhavebeenWittgenstein'sownview,hisfollowers tookitforgrantedthattheelementarystatementswhichyielded this -12criterionofmeaningwere reportsofobservations.Asweshallsee lateron,theysooncametodisagreeaboutthecharacterofthese reports.Therewasadisputeoverthequestionwhethertheywere infallible,andwhethertheyreferredtotheprivatesensationsofthe speaker,ortopublicphysicalevents.Butitwasagreedthat,inone formoranother,theyprovidedthetouchstonebyreference to whichallotherstatementswere empiricallyverified.Andsince, accordingtoWittgenstein'stheory,theyalonefurnishedthese statementswiththeirfactualcontent,theywerealsoresponsiblefor theirmeaning.Thisviewwasthensummedupinthefamous sloganthatthemeaningofapropositionisitsmethodof verification. Theassumptionbehindthissloganwasthateverythingthatcould besaidatallcouldbeexpressedintermsofelementary statements.Allstatementsofahigherorder,includingthemost abstractscientifichypotheses,wereintheendnothingmorethan shorthanddescriptionsofobservableevents.Butthisassumption wasverydifficulttosustain.Itwasparticularlyvulnerablewhenthe elementarystatementsweretakentoberecordsofthesubject's immediateexperiences:forwhileithassometimesbeen maintainedthatstatementsaboutphysicalobjectscanbefaithfully translatedintostatementsaboutsense-data,nosuchtranslation haseverbeenachieved:thereare,indeed,goodgroundsfor

supposingthatitisnotfeasible.Moreoverthischoiceofabasis raisedthequestionofsolipsismtheproblemofmakingthe transitionfromthesubject'sprivate experiencestotheexperiences ofothersandtothepublicworld.Carnap,indeed,inhisDer logischeAufbauderWelt(1928)madeavaliantattemptto reconstructourwholeapparatusofempiricalconceptsona solipsisticfoundation,takingashisstarting-pointthesingle undefinednotionofrememberedsimilarity:buthelater acknowledgedthatthisenterprisedidnotsucceed.Thepositionwas easierforthosewhotreatedelementarystatementsasdescriptions ofphysicalevents,thoughtheirrighttodothisremainedin question:theyatleastwerenottroubledbytheproblemof solipsismorbythedifficultyofreducingphysicalobjectstosensedata.Butotherdifficultiesremained.Themostseriousofall, perhaps,waspresentedbythecaseofuniversalstatementsoflaw. Forwhilethetruthofsuchastatementmaybeconfirmedbythe accumulationoffavorable instances,itisnotformallyentailedby themthepossibilitythatafurtherinstancewillrefuteitmust alwaysremainopen:andthismeansthatstatementsofthissort arenotconclusivelyverifiable.Ontheotherhand,theycanbe conclusivelyfalsifiedinthesensethatanegativeinstanceformally contradictsthem.ForthisreasonKarlPoppersuggestedinhis -13LogikderForschungthatwhatshouldberequiredofafactual statementwasjustthatitbecapableintheoryofbeingfalsified. Andhearguedthatapartfromthelogicalsuperiorityofthis criterionitwasmoreinaccordwithscientificpracticeforscientists setuphypotheseswhichtheytestbylookingforcounter-examples: whenacounter-example isdiscoveredthehypothesisisrejectedor modifiedotherwise itisretained.ButPopper'scriterionhas demeritsofitsown.Forinstance,ashehimselfrecognizes,itallows onetodenyanindefiniteexistentialstatementbutnottoaffirmit. Onecansaythattherearenoabominablesnowmen,forthiscould befalsifiedbyfindingthem,butonecannotsaythatthereare abominablesnowmen,forthiscouldnotbefalsifiedthefactthat onehadfailedtofindanywouldnotproveconclusivelythatnone existed.Whatcouldbedisprovedwouldbethatanyofthemexisted ataparticularplaceandtime,anditisonlyifthisfurther specificationisgiventhatthestatementbecomeslegitimate: otherwise itistobecountedasmetaphysical.Butthisistobring thefrontiersofmetaphysicsratherclose. Becauseofthisandotherdifficultiestheviewwhichcametoprevail amongthelogicalpositivistswasthatthedemandsthata statementbeconclusivelyverifiable,orthatitbeconclusively falsifiable,werebothtoostringentascriteriaofmeaning.They choseinsteadtobesatisfiedwithaweakercriterionbywhichitwas requiredonlythatastatementbecapableofbeinginsomedegree confirmedordisconfirmedbyobservationifitwerenotitselfan elementarystatement,ithadtobesuchthatelementary statementscouldsupportit,buttheydidnotneedtoentailitorto

entailitsnegation.Unfortunately,thisnotionof"support"or "confirmation"hasneveryetbeenadequatelyformalized.Various attemptshavebeenmadetogive"theverificationprinciple,"inthis weakerform,athoroughlypreciseexpression,buttheresultshave notbeenaltogethersatisfactory.However,theemploymentofthe principledidnotwaituponitsproperformulationitsgeneral purportwasheldtobesufficientlyclear.Ihavealreadygiven examplesofthekindofphilosophicaltalkthatitservedto eliminate:butitsdestructivenesswasnotconfinedtowhatone mightcallthegrosserformsofmetaphysics.Asemployedbythe Viennesepositivists,itmadeshortworkofmostoftheperennial problemsofphilosophy.Thus,thequestionsatissuebetween monistsandpluralists,orbetweenrealistsandidealists,were accountednolessspuriousthanquestionsaboutthelimitationsof Being,oratranscendentworldofvalues.Forwhatempiricaltest couldpossiblygotodecidewhethertheworldisone -14ormany,orwhetherthethingsthatweperceive doordonotexist outsidesomeone'smind?Itischaracteristicofsuchrival philosophicalthesesasrealismandidealismthateachisconsistent withalltheappearances,whatevertheircontentmayhappentobe. But,forthepositivist,itisjustthisthatcondemnsthem. Anobviousobjectiontotheverificationprinciple,whichthe positivists'opponentswere quicktoseizeon,isthatitisnotitself verifiable.Isupposethatitmightbetakenasanempirical hypothesisaboutthewayinwhichpeopleactuallyusetheword "meaning,"butinthatcaseitwouldappeartobefalseforitisnot contrarytoordinaryusagetosaythatmetaphysicalutterancesare meaningful.Neitherdiditssponsorsputtheprincipleforwardasthe resultofanysuchempiricalinvestigation.Butthenwhatstatusdid theythinkithad?Mightitnotitselfbemetaphysical?Surprisingly, Wittgensteinaccededtothischarge."Mypropositions,"hesaidat theendoftheTractatus,"areelucidatoryinthisway:hewho understandsmefinallyrecognizesthemassenseless,whenhehas climbedoutthroughthem,onthem,overthem.(Hemustsoto speakthrowawaytheladder,afterhehasclimbeduponit.)He mustsurmountthesepropositionsthenheseestheworldrightly." Butthisisavainattempttohaveitbothways.Nodoubtsome piecesofnonsensearemoresuggestivethanothers,butthisdoes notgivethemanylogicalforce.Iftheverificationprinciplereallyis nonsensical,itstatesnothingandifoneholdsthatitstates nothing,thenonecannotalsomaintainthatwhatitstatesistrue. TheViennaCircletendedtoignorethisdifficulty:butitseemsto mefairlyclearthatwhattheywereinfactdoingwastoadoptthe verificationprincipleasaconvention.Theywerepropoundinga definitionofmeaningwhichaccordedwithcommonusageinthe sensethatitsetouttheconditionsthatareinfactsatisfiedby statementswhichareregardedasempiricallyinformative.Their treatmentofaprioristatementswasalsointendedtoprovidean

accountofthewayinwhichsuchstatementsactuallyfunction.To thisextenttheirworkwasdescriptiveitbecameprescriptive with thesuggestionthatonlystatementsofthesetwokindsshouldbe regardedaseithertrueorfalse,andthatonlystatementswhich werecapableofbeingeithertrueorfalseshouldberegardedas literallymeaningful. Butwhyshouldthisprescriptionbeaccepted?Themostthathas beenprovedisthatmetaphysicalstatementsdonotfallintothe samecategoryasthelawsoflogic,orasscientifichypotheses,or ashistoricalnarratives,orjudgmentsofperception,oranyother commonsensedescriptionsofthe"natural"world.Surelyitdoes not -15followthattheyareneithertruenorfalse,stilllessthattheyare nonsensical? No,itdoesnotfollow.Orrather,itdoesnotfollowunlessone makesitfollow.Thequestioniswhetheronethinksthedifference betweenmetaphysicalandcommonsenseorscientificstatements tobesufficientlysharpforittobeusefultounderlineitinthisway. Thedefectofthisprocedure isthatittendstomakeoneblindto theinterestthatmetaphysicalquestionscanhave.Itsmeritisthat itremovesthetemptationtolookuponthemetaphysicianasasort ofscientificoverlord.Neitheristhisatrivialmatter.Ithasfartoo oftenbeenassumedthatthemetaphysicianwasdoingthesame workasthescientist,onlydoingitmoreprofoundlythathewas uncoveringadeeperlayeroffacts.Itisthereforeimportantto emphasizethatheisnotinthissensedescribinganyfactsatall. Butthenwhatishedoing?Whatisthepointofsaying,like McTaggart,thattimeisunrealor,likeBerkeley,thatphysical objectsareideasinthemindofGodor,likeHeidegger,thatthe "nothingnihilatesitself"?Itshouldnotbeassumedthatthereisa generalanswertothisquestion,thatmetaphysiciansarealways doingthesamesortofthing.Onemustbegininanycaseby lookingatthecontextinwhichsuchpronouncementsoccur. Heidegger'sremarkisapieceofverbiage,butitcontributesinits fashiontohisdevelopmentofthethemethatitisamatterfor wonderthattheworldexists.Whyisthereanythingatall,heasks, andnotrathernothing?Thisisindeedthekindofquestionthat peopleexpectphilosopherstoput:ithasanairofprofundityabout it.Thetroubleisthatitdoesnotadmitofanyanswer.Ontheface ofit,McTaggart'scontentionthattimeisunrealseemshardlymore sensible.Iftakenliterally,asimplyingthatnothingeverhappens,it isgrotesquelyfalse.Andifitisnottobetakenliterally,whatdoesit mean?TheansweristobefoundbylookingatMcTaggart's arguments.Heshowshimselftheretobeperplexedbytheideaof thepassageoftimehetriestoprove thatthenotionofanevent's beingsuccessivelyfuture,present,andpastinvolvesavicious infiniteregress.Theproofisinvalid,butwecanlearnsomething fromit.Indefendingouruseoftemporalexpressionsagainst

McTaggart'sargumentswemayreachaclearerunderstandingofall thatitimplies.Berkeley,again,wasconcernedtodiscoverwhat couldbemeantbysayingthatphysicalobjectsexist:heconvinced himselfbyplausibleargumentsthatwhenwespeakofphysical objectswecanbereferringonlytocollectionsof"sensible qualities,"theexistenceofwhichconsistsintheirbeingperceived andhethenbroughtinGodasthepermanentsen-16soriumwhichwasneededtokeepthingsinbeing.Hisarguments canbewithstoodbuttheydoraiseimportantphilosophical problemsaboutthemeaningandjustificationofthestatements thatwemakeaboutthe"externalworld." TheViennesepositivistswerechieflyinterestedintheformaland thenaturalsciences.Theydidnotidentifyphilosophywithscience, buttheybelievedthatitoughttocontributeinitsownwaytothe advanceofscientificknowledge.Theythereforecondemned metaphysicsbecauseitfailedtomeetthiscondition.Thelogical analystsofto-dayaremoreindulgent.Theytooareopposedto metaphysicsinsofarasitismerelyrhapsodical:eveninthesphere ofethicstheywishtodissociatephilosophyfrompreaching.But theyallowthatthemetaphysicianmaysometimesbeseeingthe worldinafreshandinterestingwayhemayhavegoodreasonfor beingdissatisfiedwithourordinaryconcepts,orforproposingto revise them.Inmanycasesnodoubtheisthevictimofalogical errorbutsucherrorsmaybeinstructive.Ifphilosophicalproblems arise,asWittgensteinthought,becauseweareledastraybycertain featuresofourlanguage,themetaphysician,byhisvery extravagancies,mayalsocontributetotheirdissolution.

III.LANGUAGEANDFACTWiththeireliminationofmetaphysics,theViennesepositivists hopedthattheyhadalsoputthetheoryofknowledge behindthem, butinthistheywere deceived.Thefirstsourceoftroublewasthe notionofelementarystatements.Boththeircharacterandstatus becameamatterofdispute. Attheoutset,asIhavesaid,theprevailingviewwasthatthese statementsreferredtothesubject'sintrospectibleorsensory experiences.Thisviewwasadoptedbecauseitseemedtofollow fromtheequationofthemeaningofastatementwiththemethod ofitsverification.Forinthelastresortitisonlythroughsomeone's havingsomeexperience thatanystatementisactuallyverified.In mostcases,theverificationwouldconsistintheperceptionofsome physicalobjectbutitwasheld,followingRussellandultimately Berkeley,thatperceivingphysicalobjectswastobeanalyzedin termsofhavingsensations,orasRussellputit,ofsensingsensedata.Thoughphysicalobjectsmightbepubliclyaccessible,sensedatawere takentobeprivate.Therecouldbenoquestionofour literallysharingoneanother'ssense-data,anymorethanwecan literallyshareoneanother'sthoughtsorimagesorfeelings.The

resultwasthatthetruth -17ofanelementarystatementcouldbedirectlycheckedonlybythe persontowhoseexperienceitreferred.Andnotonlywashis judgmentsovereigninthemostfavorablecase,itwasheldtobe infallible.Onecanindeedbemistakenabouttheexperiencesthat oneisgoingtohaveinthefuture,orevenaboutthosethatone hashadinthepastitisnotmaintainedthatourmemoriescannot deceiveus:butifonesetsoutmerelytorecordanexperience that oneisactuallyhaving,then,onthisview,thereisnopossibilityof error.Sinceonecanlie,one'sstatementmaybefalsebutone cannotbeindoubtormistakenaboutitstruth.Ifitisfalseone knowsittobeso.Awayinwhichthispointissometimesputisby sayingthatstatementsofthiskindare"incorrigible." Thisconceptionofelementarystatementswasexposedtoattackon variousgrounds.Thereweresometowhomitseemedthatno empiricalstatementcouldbeincorrigible,inthesenserequired. Theywere therefore inclinedtomaintaineitherthatonecouldbe mistakenaboutthecharacterofone'spresentexperience,sothat thestatementswhichpurportedtorecorditwere falliblelikethe rest,orthatthese"directrecordsofexperience"werenotgenuine statements,sincetheypurchasedtheirsecurityattheexpenseof sacrificingalldescriptivecontent.Butthemostseriousdifficultylay intheprivacyoftheobjectstowhichtheelementarystatements weresupposedtorefer.Ifeachoneofusisboundtointerpretany statementasbeingultimatelyadescriptionofhisownprivate experiences,itishardtoseehowwecanevercommunicateatall. Eventospeakof"eachoneofus"istobegaquestionforitwould seemthatonthisviewthesuppositionthatotherpeopleexistcan havenomeaningformeunlessIconstrueitasahypothesisabout myownobservationsofthem,thatis,aboutthecourseofmyown actualorpossibleexperiences.ItwasmaintainedbyCarnapand othersthatthesolipsismwhichseemedtobeinvolvedinthis positionwasonlymethodologicalbutthiswaslittlemorethanan avowalofthepurityoftheirintentions.Itdidnothingtomitigate theobjectionstotheirtheory. Atfirst,itwasthoughtthatthedifficultyaboutcommunicationcould bemetbydrawingadistinctionbetweenthecontentofexperiences andtheirstructure.Content,itwasmaintained,was incommunicable.Sinceotherpeoplecannotsensemysense-data, orsharemythoughtsorfeelings,theycannotverifythestatements thatImakeaboutthemneithercanIverifythecorresponding statementsthattheymakeabouttheirexperiences.AndifIcannot verifythem,Icannotunderstandthemeither.Tothisextentwe inhabitentirelydifferentworlds.Whatcanbeverified,however,is thattheseworlds -18-

haveasimilarstructure.Ihavenomeansoftellingthatthefeeling whichanotherpersonrecordswhenhesaysthatheisinpainisat alllikethefeelingthatIcallpain:Ihavenomeansoftellingthat thecolorswhichheidentifiesbytheuseofcertainwordslookatall thesametohimasthecolorsforwhichIusethesewordslookto me.ButatleastIcanobservethatweapplythewordsonthe sameoccasions,thathisclassificationofobjectsaccordingtotheir colorcoincideswithmineIcanobservethatwhenhesaysheisin painhedisplayswhatIregardastheappropriatesigns.Andthisis allthatisrequiredforcommunication.Itdoesnotmattertome whatmyneighbour'sexperiencesactuallyare:forallthatIcan everknowtheyareutterlydifferentfrommine.Whatmattersis thatthestructure ofourrespectiveworldsissufficientlyalikefor metobeabletorelyontheinformationthathegivesme.Anditis inthissenseonlythatwehaveacommonlanguagewehave,asit were,thesamecanvaswhicheachofuspaintsinhisownprivate fashion.Itfollowsthatiftherearepropositions,likethe propositionsofscience,whichhaveaninter-subjective meaning, theymustbeinterpretedasdescriptionsofstructure. AsIhavealreadyremarked,thefundamentalobjectiontothisview isthatitinconsistentlyputsthe"private worlds"ofotherpeopleon alevelwithone'sownitresultsinacurious,andindeed contradictory,theoryofmultiplesolipsism.But,apartfromthis,the distinctionwhichittriestomakebetweencontentandstructure doesnotseemtobetenable.Forwhatwouldbeanexampleofa statementwhichreferredonlytostructure?Thereisanechohere ofLocke's"primaryqualities."Butstatementswhichrefertothe "geometrical"propertiesofobjects,to"figure,extension,number andmotion"havetobeinterpretedintermsofcontent,justas muchasstatementswhichrefertocolorsandsounds.IfIhaveno meansofknowingthatmyneighbormeansthesameasIdobyhis useofcolor-words,Ihaveequallynomeansofknowingthathe meansthesamebyhisuseofwordswhichrefertospatialrelations ortonumericalquantities.IcannottelleventhatwhatItaketobe thesamewordreallyisthesameforhim.AllthatIamleftwithis theapparentharmonyofourbehavior.Moreoveritseemsthatthe attempttodrawadistinctionwithintheboundariesofdescriptive languagebetweenwhatcanandcannotbecommunicatedmustbe self-defeating.ItleadstotheabsurditytowhichRamseydraws attentioninhisshortpaperon"Philosophy,"whichisincludedinthis volume:"thepositionofthechildinthefollowingdialogue:'Say breakfast.''Can't.''Whatcan'tyousay?''Can'tsaybreakfast.'" -19Becauseofsuchdifficulties,Neurath,andsubsequentlyCarnap, rejectedthiswholeconceptionofelementarystatements.They arguedthatifelementarystatementswere toserveasthebasisfor theintersubjective statementsofscience,theymustthemselvesbe intersubjective.Theymustrefer,nottoprivateincommunicable experiences,buttopublicphysicalevents.Moregenerally, statementswhichostensiblyrefertoexperiences,orto"mental"

statesorprocessesofanykind,whetherone'sownoranybody else's,mustallbeequivalentto"physicalstatements":foritisonly inthiswaythattheycanbepubliclyintelligible.Thisisthethesisof physicalism.Ishallnotdwelluponithere,asIhaveinsertedan articlebyCarnap,"PsychologyinPhysicalLanguage",whichsetsit outatlength. Theviewthattheywere includedin"thephysicallanguage"took awayfromelementary,or,asNeurathandCarnapcalledthem, "protocol,"statementstheirprivilegedposition.Theywereno longerthoughttobeincorrigible.Theirtruth,likethatofanyother physicalstatements,wasalwaysopentoquestion.But,morethan this,theylosteventheirjudicialstatus.Ifaprotocol-statement conflictedwithastatementofahigherorder,suchasascientific hypothesis,oneorotherofthemwouldhavetobeabandoned,but itneednotnecessarilybethescientifichypothesis:incertain circumstancesitmightbemoreconvenienttorejecttheprotocolstatementinstead. Ascanbeseenfromhispaperonthefoundationofknowledge ("berdasFundamentderErkenntnis")Schlickfoundthisconclusion unacceptable.Hearguedthattotreatthereportsofobservation, whichwaswhatprotocol-statementsweresupposedtobe,inthis cavalierfashion,wastoputscientifichypotheses,andindeedall would-beempiricalstatements,outsidethecontroloffact.Neurath andCarnap,however,werenotimpressedbythisargument.They haddecidedbythistimethatitwasmetaphysicaltotalkof comparingstatementswithfacts.Forwhatcouldthis"comparison" beifnotalogicalrelation?Andtheonlythingtowhichastatement couldstandinanylogicalrelationwasanotherstatement. Consequently,theywere ledtoadoptacoherencetheoryoftruth. Theirversionofthecoherencetheorywasinsomewaysless objectionablethanthatwhichtheHegelianidealistshadmade familiar.Evenso,forthereasonswhichIsetoutinmypaperon VerificationandExperience,itseemstomequiteuntenable. CarnaphimselfabandoneditafterhehadbeenconvincedbyTarski oftherespectabilityofsemanticsforsemanticsprovidesuswith themeansofreferringtotherelationshipbetweensentencesand whattheyareusedtosignify.Itprovides,asTarskishowed,an adequatereformu-20lationofthecorrespondencetheoryoftruth.Ontheotherhand Carnaphasnot,sofarasIknow,abandonedthethesisof physicalism.But,ifhedoesstillholdit,Ithinkthatheismistaken. Itnowseemscleartomethatstatementsabouttheexperiencesof otherscannotbelogicallyequivalenttostatementsabouttheir overtbehaviorwhiletomaintainthatthestatementswhichone makesaboutone'sownexperiencesareequivalenttostatements aboutthepubliclyobservable conditionofone'sbodyis,asRamsey putit,tofeignanaesthesia.Nevertheless,thedifficultieswhichthis thesiswasdesignedtomeetremain.Neitherisiteasytoseehow

elsetheycanbeavoided.Isuggest,however,thatmuchofthe troublemayarisefromtheacceptanceoftwofalseassumptions, thefirstbeingthatforalanguagetobepublicitmustreferto publicobjects,andthesecondthatinmakinganempirical statementoneisalwaysreferringtoone'sownexperiences.Istill thinkthatempiricalstatementsmustrefertoexperiences,inthe sensethattheymustbeverifiable butthereferenceneednotbe totheexperiencesofanyoneperson,asopposedtoanyother.But Iacknowledgethatthisattemptto"neutralize"theverification principlemeetswithconsiderabledifficultiesofitsown.

IV.ETHICSOneoftheattractions,especiallyforNeurath,ofthethesisof physicalismwasthatitsupportedthedoctrineoftheUnityof Science.Inoneaspect,thiswaslessofadoctrinethanaprogram itwasdesiredthatscientistsofdifferentdisciplinesshould collaboratemorecloselywitheachotherandwithphilosophersthan theyusuallydo:butitwasalsomaintainedthattheywere,or shouldbe,speakingacommonlanguage,thatthevocabularyof thesciencesshouldbeunified.Thus,theViennaCirclerejectedthe view,whichmanystillhold,thatthereisaradicaldistinction betweenthenaturalandthesocialsciences.Thescaleanddiversity ofthephenomenawithwhichthesocialsciencesdealtmadethem lesssuccessfulinestablishingscientificlaws,butthiswasadifficulty ofpractice,notofprinciple:theytoowere concernedintheend withphysicalevents. Eventhosewhodidnotacceptthethesisofphysicalismagreedthat therewasnoessentialdifferenceinaimormethodbetweenthe variousbranchesofscience.Inthesocialsciences,nolessthanin thenatural,anattemptwasmadetoformulatehypotheseswhich couldbetestedbyobservation.ThusSchlick,whoincludedethics amongthesocialsciences,deniedthatitsresultsdependedupon theuseofanyspecialfacultyofmoralintuition.Thequestions which -21ariseinethicsare,inhisopinion,questionsoffactwhypeoplehold theprinciplesthattheydo,whatitisthattheydesire,andhowtheir desirescanbefulfilled.Inshort,hisgeneralpositionisverysimilar tothatoftheUtilitarians.Ithasmuchthesamemeritsandmuch thesamedefects. TheViennaCircleasawholewasnotverygreatlyinterestedin ethicsbutitdidnotdisputeSchlick'sviewthatifethicalstatements weretobebroughtintothescientificfold,theymustbehandledin thewaythatheproposed.Theonlyquestionwaswhetherthey belongedwithinthefold,whethertheywere statementsoffactat all.Carnap,forexample,maintainedthattheywerenothesaid thattheywere disguisedimperatives.Hedidnotdevelopthis suggestion,butithassincebeengivensubstancebyR.M.Harein hisbookonTheLanguageofMorals(1952).Thisimperative theory

ofethicsmayberegardedasaversionoftheso-calledEmotive Theorywhich,mainlythroughtheworkofEnglishandAmerican philosophers,hascometobemostcloselyassociatedwithlogical positivism.Thesalientpointisthatethicalstatementsarenot descriptiveofnaturalfacts,stilllessofanallegednon-naturalworld ofvalues:theyarenotdescriptiveofanythingatall.Theproblemis thentodeterminehowtheydofunction.InC.L.Stevenson'sbook EthicsandLanguage(1944),where theemotivetheorywasfirst workedoutindetail,itwasarguedthatethicalstatementsserved thedualpurposeofexpressingtheirauthor'sapproval,or disapproval,ofwhateverwasinquestionandrecommendingothers tosharehisattitude.Helaidparticularemphasisuponthe persuasive useofethicalterms.Hisviewshavenotpassedwithout criticismevenfromthosewhosharehisgeneralstandpointbutthe alternative accountsofethicswhichthesecriticshaveputforward belong,asitwere,tothesamefamily. Indiscussionsoflogicalpositivism,thistheoryofethicsisaptto receive adisproportionatemeasureofattention,consideringthatit standsontheperipheryofthesystem.Onereasonforthisisthatit hasbeenthought,quitewrongly,thatitwasanonslaughtupon morals.Ithasevenbeenasserted,withoutashadowofempirical evidence,thatitsadvocateswerecorruptersofyouth.Infact,the theoryonlyexplorestheconsequencesofasoundandrespectable pointoflogicwhichwasalreadymadebyHumethatnormative statementsarenotderivablefromdescriptivestatements,or,as Humeputsit,that"ought"doesnotfollowfrom"is."Tosaythat moraljudgmentsarenotfact-statingisnottosaythattheyare unimportant,oreventhattherecannotbeargumentsintheir favor.Buttheseargumentsdonotworkinthewaythatlogicalor scientificargumentsdo.Itisnotasiftheintuitionistshad discoveredgroundsformoral -22judgmentswhichtheemotiviststriedtotakeaway.Onthe contrary,asMr.Strawsonshowsinhispaperon"Ethical Intuitionism,"theintuitioniststhemselvesdonotsupplyany foundationformoraljudgments.Itisthereforeonlyonpersonal groundsthattheycanbeentitledtoputthemselvesforwardasthe guardiansofvirtue.

V.PHILOSOPHICALANALYSISSomeofthedissatisfactionthatisarousedbytheemotivetheoryof ethics,andindeedbylogicalpositivismingeneral,maybedueto thefactthatpeoplearestillinclinedtolooktophilosophyfor guidanceastothewaytheyoughttolive.Whenthisfunctionis deniedtoit,andwhenitisdeniedeventhepossibilityof penetratingtheveilofappearanceandexploringthehiddendepths ofreality,theyfeelthatitisbeingtrivialized.Ifthistime-honored programisnonsensical,whatremains?AsRamseysays, "philosophymustbeofsomeuse,andwemusttakeitseriously."

Butwhatfunctiondothepositivistsleaveittoperform? FromthepointofviewofWittgenstein'sTractatus,itsfunction wouldappeartobepurelynegative,thoughnotforthatreason unimportant."Therightmethodofphilosophy,"saidWittgenstein, "wouldbethis.Tosaynothingexceptwhatcanbesaid,i.e.the propositionsofnaturalscience,i.e.somethingthathasnothingto dowithphilosophy:andthenalways,whensomeonewishedtosay somethingmetaphysical,todemonstratetohimthathehadgiven nomeaningtocertainsignsinhispropositions.Thismethodwould beunsatisfyingtotheother--he wouldnothavethefeelingthatwe wereteachinghimphilosophy--butitwouldbetheonlystrictly correctmethod."Thisratherdepressingviewofthephilosopher's dutywasnotstrictlymaintainedbyWittgensteinhimself.The PhilosophicalInvestigationscontainsagreatdealmorethana seriesofproofsthatpeoplehavefailedtoattachanymeaningto certainsignsintheirpropositions.Neverthelessitstillgivesthe impressionthattophilosophizeistogetintoamuddle,ortorescue oneselforothersfromone.Philosophyis"abattleagainstthe bewitchmentofourintelligencebymeansoflanguage.""Whatis youraiminphilosophy?Toshowtheflythewayoutofthefly bottle."Allthesame,itismeritoriousoftheflytobethere.Itisthe criticalintelligencesthatgetthemselvesbewitched. TheTractatusleftnoroomforphilosophicalpropositions.Thewhole fieldofsignificantdiscoursewascoveredbyformalstatementson theonehandandempiricalstatementsontheother.There remainednothingforphilosophytobeabout.Itwasforthisreason -23thatWittgenstein,andalsoSchlick,maintainedthatphilosophywas notadoctrinebutanactivity.Theresultofphilosophizing,said Schlick,wouldnotbetoaccumulateastockofphilosophical propositions,buttomakeotherpropositionsclear. Buttomakepropositionsclearitmustbepossibletotalkabout them.AsRussellpointsoutinhisintroductiontotheTractatus, Wittgensteinappearednottoallowforthis,ortoallowforitonlyto alimitedextent.Heimpliedthatanattempttodescribethe structure oflanguage,asopposedtoexhibitingitinuse,must resultinnonsense.Butthoughthisconclusionmayhavebeen formallyacceptedbySchlick,itwasinpracticedisregardedbythe ViennaCircle.Thus,Carnap,inhisDerLogischeAufbauderWelt, explicitlysethimselftodescribethestructureoflanguageby devisingwhathecalleda"Konstitution-System,"inwhichthe varioustypesoflinguisticexpressions,orconcepts,wereassigned theirproperplacesinadeductivehierarchy.Ifhehadbeen questionedaboutthestatusofhisownpropositions,Isupposethat hewouldhavesaidthattheywereanalyticconsisting,astheydid, ofdefinitionsandtheirlogicalconsequences,theywouldbelongto therealmofformaltruths.Howeverthismaybe,hecertainly believedthatthesepropositionsweresignificantandhecarriedthe ViennaCirclewithhiminholdingthattheywerethesortof

propositionsthataphilosophershouldbeexpectedtoputforward. Theattempttobringphilosophywithinthedomainoflogicwas carriedfurtherbyCarnapinhisbookontheLogicalSyntaxof Language."Philosophy,"hesaysintheforewordtothisbook,"isto bereplacedbythelogicofscience--thatistosaybythelogical analysisoftheconceptsandsentencesofthesciences,forthelogic ofscienceisnothingotherthanthelogicalsyntaxofthelanguage ofscience."Thoughhespeakshereofthelanguageofscience,he doesnotholdthatthereneedbeonlyone.Alternative languagesystemsmaybedevised,andthechoicebetweenthemis amatterofconvenience:thisisanimportantdeparturefromthe positionofWittgenstein'sTractatus.AccordingtoCarnap,a languageischaracterizedbyitsformation-rules,whichspecifywhat sequencesofsignsaretocountaspropersentencesofthe language,andbyitstransformation-rules,whichlaydownthe conditionsunderwhichsentencesarevalidlyderivable fromone another.Itmightbethoughtthatifthelanguagewastohaveany empiricalapplicationitmustalsocontainmeaning-rulesruleswhich wouldcorrelate itsexpressionswithobservablestatesofaffairs:but Carnap,inthisformaliststageofhisphilosophy,thoughtthathe coulddispensewiththem.Hebelieved,quitemistakenly,that statementsofverbalequiva-24lencescoulddotheworknotonlyofsemanticstatementsbuteven ofostensivedefinitions. ItisinthisbookthatCarnapmakeshisfamousdistinctionbetween thematerialandtheformalmodesofspeech.Hedistinguishes threekindsofsentences:"object-sentences,"suchas"5isaprime number"or"Babylonwasabigtown,""pseudo-objectsentences," suchas"Five isnotathing,butanumber""Babylonwastreatedof inyesterday'slecture,"and"syntacticalsentences"suchas"'Five'is notathing-word,butanumberword.""Theword'Babylon' occurredinyesterday'slecture."Thepseudo-objectsentencesare saidtobe"quasi-syntactical,"becausetheyaresyntactical sentencesmasqueradingasobject-sentences.Theyare"quasisyntacticalsentencesofthematerialmodeofspeech."Translation fromthematerialintotheformalmodereplacesthembytheir syntacticalequivalents.Toputitlesstechnically,whenonespeaks intheformalmodeoneisovertlyspeakingaboutwordswhenone speaksinthematerialmodeoneisspeakingaboutwordswhile seemingtospeakaboutthings.Thisdistinctiondoesnotofcourse applytoobject-sentences.Carnapwasnotmaintaining,assome criticshavesupposed,thatalldiscourseisaboutwords.Whathedid appeartooverlook,however,wastheexistenceofafurther category,thatofpseudo-syntacticalsentencessentenceswhich wereaboutthingsbutseemedtobeaboutwords.Asaresult,he wasapttofallintotheerroroftreatingthesesentencesasifthey weresyntactical. Itiswiththeoppositeerrorthathereproachedmostother

philosophers.Hemaintainedthatphilosophicalstatementswere syntactical,butthattheyhadbeentreatedasiftheywere objectstatements,becauseofthefashionforexpressingtheminthe materialmodeofspeech.Thus,totakeaselectionofhisexamples, hearguedthat"Theworldisthetotalityoffacts,notofthings,"the firstpropositionofWittgenstein'sTractatus,wasequivalentto "Science isasystemofsentences,notofnames":"This circumstanceislogicallynecessary...logicallyimpossible... logicallypossible"became"Thissentenceisanalytic... contradictory...notcontradictory":Kronecker'sepigram"God createdthenaturalnumberseverythingelseinmathematicsisthe workofman"wasawayofsaying"Thenatural-numbersymbols areprimitivesymbolsothernumericalexpressionsareintroduced bydefinition.""Theonlyprimitive dataarerelationsbetween experiences"wasequivalentto"Onlytwo-ormore-termed predicateswhoseargumentsbelongtothegenusofexperienceexpressionsoccurasdescriptive primitive symbols":"Timeisinfinite inbothdirections"to"Everypositiveornegativerealnumber expressioncanbeusedasatime-co-ordinate."Eventhe -25questionofdeterminismwassaidto"concernasyntactical differenceinthesystemofnaturallaws."Inthiswayrival philosophicaltheses,iftheymadeanysenseatall,were representedasalternative proposalsaboutthewayone'slanguage shouldbeformed.Theywerenottrueorfalse,butonlymoreor lessconvenient. IthinkthatCarnap'sdistinctionbetweenthematerialandformal modeswasfruitful,inthatitcalledattentiontothefactthatmany philosophicalstatementsaredisguisedstatementsaboutlanguage. Wherehewentwrongforthemostpartwasinsupposingthatthey weresyntactical.Forwhattheyareconcernedwithisnottheform ororderofwords,buttheiruse.Thisdoesnotcomeoutin Carnap'sexamplesbecauseheillicitlysmugglessemanticsinto syntax.Thus,"experience-expressions"isnotasyntacticalterm. Whatmakesanexpressionan"experience-expression"isnotits havinganyparticularformbutitsbeingusedtorefertoan experience.Butthenthequestionwhatistocountasanexperience becomesimportant.Neitherisittobesettledbyanarbitrary decision. Inhismorerecentworks,Carnaphasrecognizedthelegitimacyof semantics,andindeeddevotedconsiderableattentionbothtothe developmentofsemantictheoryandtobuildingupsemantic systems.Aninterestingeffectofthishasbeenamarkedrelaxation ofhisphilosophicalausterity.Havingacquiredtherighttospeakof thereference ofwordstothings,hehasallowedalmostanytypeof wordtodenoteitsspecialsortofobject,thusrecreatingthe baroqueuniversewhichRussellhadlaboredtodepopulate.His defenseofthisapparentextravagance istobefoundinhispaper on"Empiricism,SemanticsandOntology,"where hedistinguishes

between"internal"questionswhicharisewithinagivenconceptual frameworkand"external"questionswhichconcernthestatusand legitimacyoftheframeworkitself.Hehimselfhasalwaysbeen chieflyinterestedintheexternalquestions:hehasthoughtithis businessasaphilosophertodeviselinguisticsystemsandelaborate conceptsthatwillbeusefultothescientist.Andnooneshoulddeny thatthisisaseriousandlegitimateactivity.Whereheiswrong,I think,isinassumingthattheexternalquestionspresentnoserious problem:thatnothingmoreisatissuethanachoiceoflinguistic forms. Itisthisdisregardofquestionsaboutthestatusofhislinguistic frameworksthatseparatesCarnapfromtheAmericanphilosophers, likeQuineandGoodman,whoresemblehimintheirsystematic approachtophilosophyandintheirpreferenceforformal techniques.Thesephilosophersareinterestedinwhattheycall ontology,thatis,inthequestionhowfarone'schoiceoflanguage commitsonetosayingthatcertainthingsexist."Tobe,"says Quine,"istobe -26thevalueofavariable":andthismeansthattheextentofwhat Russellcalledthe"furniture"oftheworlddependsupontherange ofpredicatesthatareneededtodescribeit.BothQuineand Goodmanwishthisfurnituretobeashardandspareaspossible. They"renounce abstractentities"notjustbecausetheywishto exercisetheirlogicalingenuityinseeinghowwelltheycando withoutthem,butbecausetheycannotbringthemselvestobelieve thattheyexist.Inthesamespirit,Goodmanforgoesmakingany useofthenotionofpossible,asopposedtoactual,things,orofthe distinctionbetweencausalandaccidentalconnections,orofthat betweenanalyticandsyntheticstatements."Youmay,"hesays, "decrysomeofthesescruplesandprotestthattherearemore thingsinheavenandearththanaredreamtofinmyphilosophy.I amconcerned,rather,thatthereshouldnotbemorethingsdreamt ofinmyphilosophythanthereareinheavenorearth."Itisnot clear,however,eitherinhiscaseorinQuine's,onwhatthis demandforstringenteconomyisbased.Quine,indeed,allowsin theendthatthequestionofwhatthereismustbesettledon pragmaticgrounds.AndsoherejoinsCarnapbuthispragmatism ismuchlessserene. Aninterestincategories,whichisanotherwayofapproachingthe problemofwhatthereis,ischaracteristicalsooftheBritish philosopherswhohavebeeninfluencedbythelaterworkof Wittgenstein.But,forthemostpart,theyareconcernednotso muchwithtryingtoeliminatecertaintypesofentity,orto"reduce" onetoanother,aswithbringingouttheresemblancesand differencesinthefunctioningofthestatementswhichostensibly refertothem.AtechniquewhichWittgensteinhimselfusesforthis purposeisthatofdevisingwhathecallslanguagegames.Theidea isthatbystudyingdistortedorsimplifiedmodelsofouractual

languagewecanobtainaclearerinsightintothewayitreally works.Thisisonewayofprotectingusagainsttheerror,intowhich wesoeasilyfall,ofassumingthatsomethingmustbethecase, insteadoflookingandseeingwhatactuallyisthecase."Where our languagesuggestsabodyandthereisnone,there,weshouldlike tosay,isaspirit."Butthisistoforsakedescriptionforbogus explanation.Veryoftenthementalprocesseswhichweareledto postulatejustdonotoccur.Forinstance,"itisnomoreessentialto theunderstandingofapropositionthatweshouldimagineanything inconnectionwithitthanthatweshouldmakeasketchfromit." SuchremarksforeshadowRyle'sattackuponthemythof"theghost inthemachine."AndmuchasWittgensteindislikedCarnap's methods,thereisanechoofphysicalisminhisdictumthat"an 'innerprocess'standsinneedofoutwardcriteria." -27IsupposethatWittgensteinismainlyresponsiblefortheprevalent interestinthequestionhowwordsareordinarilyused,though accounthasalsotobetakenoftheinfluenceofG.E.Moore.It doesnotseemtome,however,thatMoorehaseverbeenso greatlyconcernedwithordinaryusageassuch.Hehasbeen concernedwithupholdingthe"commonsenseview"oftheworld andwithanalyzingthepropositionswhichexemplifyitbuthehas notinsistedthatwelimitourselvestoordinaryusageincarryingout thisanalysis.Whenhedoesappealtoordinaryusageitismainlyas aweaponfordealingwithotherphilosophers.Heshowsthatiftheir wordsaretakenliterally,theyareusingthemtomakestatements whicharemanifestlyfalse.Itremainspossiblethattheyaresaying somethingquitedifferentfromwhattheywouldappeartobe saying,butthenthediscoveryoftheirmeaningpresentsaproblem. Iftheyarenotusingwordsinanyordinarysense,thesensein whichtheyareusingthemhastobemadeclear. Tomymind,themainachievementofthe"ordinary-language school"hasbeentheirexaminationanddissectionofthe "unscientific"usesoflanguage.AgoodexampleofthisisJ.L. Austin'sdescriptionofwhathecallsperformative statements: statementslike"Iknow..."or"Ipromise..."ofwhichthe purposeisnottoassertafactbuttocommitthespeakerincertain waysortooffersomesortofguarantee.Towhatimaginative lengthsthisgreaterflexibilityintheapproachtolanguagecanlead isindicatedbyDr.Waismann'spaperwhichconcludesthisvolume. Itshowsthatthecurrentconceptionofphilosophicalanalysishas spreadfarbeyondRamsey'sideaofphilosophyassimplyissuingin definitions.ButRamseywasrightinsayingthatitis"allpartofthe vitalworkofclarifyingandorganizingourthought."

VI.IncompilingthisanthologyIhavetriedtoillustratethehistorical developmentoflogicalpositivism,therangeofitsinterestsandthe mainpointsofcontroversy.Lackofspacehasobligedmetopass

overmanypiecesthatIshouldhavelikedtoinclude.Inparticular,I amsorrytohavehadnoroomforQuine'spaperon"Truthby Convention,"inwhichthepositivists'accountofaprioristatements iseffectivelycriticized,orforCarnap'sinfluentialarticleson "TestabilityandMeaning."Itisespeciallytoberegrettedthatthe volumecontainsnothingofWittgenstein.ButneithertheTractatus LogicoPhilosophicusnorthePhilosophicalInvestigations,foralltheir episodiccharacter,isaworktowhichonecandojusticeby selectingpassages.Theyhavetobereadasawhole. -28-

LogicalAtomism-29[Thispageintentionallyleftblank.] -30-

1 LogicalAtomismBYBERTRANDRUSSELL THEPHILOSOPHYwhichIadvocateisgenerallyregardedasa speciesofrealism,andaccusedofinconsistencybecauseofthe elementsinitwhichseemcontrarytothatdoctrine.Formypart,I donotregardtheissuebetweenrealistsandtheiropponentsasa fundamentaloneIcouldaltermyviewonthisissuewithout changingmymindastoanyofthedoctrinesuponwhichIwishto laystress.Iholdthatlogiciswhatisfundamentalinphilosophy, andthatschoolsshouldbecharacterizedratherbytheirlogicthan bytheirmetaphysic.Myownlogicisatomic,anditisthisaspect uponwhichIshouldwishtolaystress.ThereforeIpreferto describemyphilosophyas"logicalatomism,"ratherthanas "realism,"whetherwithorwithoutsomeprefixedadjective. Afewwordsastohistoricaldevelopmentmaybeusefulbywayof preface.Icametophilosophythroughmathematics,orrather throughthewishtofindsomereasontobelieveinthetruthof mathematics.Fromearlyyouth,Ihadanardentdesiretobelieve thattherecanbesuchathingasknowledge,combinedwithagreat difficultyinacceptingmuchthatpassesasknowledge.Itseemed clearthatthebestchanceoffindingindubitabletruthwouldbein puremathematics,yetsomeofEuclid'saxiomswere obviously doubtful,andtheinfinitesimalcalculus,asIwastaughtit,wasa massofsophisms,whichIcouldnotbringmyselftoregardas anythingelse.Isawnoreasontodoubtthetruthofarithmetic,but Ididnotthenknowthatarithmeticcanbemadetoembraceall

traditionalpuremathematics.AttheageofeighteenIreadMill's Logic,butwasprofoundlydissatisfiedwithhisreasonsforaccepting arithmeticandgeometry.IhadnotreadHume,butitseemedto methatpureempiricism(whichIwasdisposedtoaccept)must leadtoscepThisessaywasRussell'scontributiontoContemporary BritishPhilosophy,firstseries(ed.J.H.Muirhead),abook publishedin1924.Itisherereprintedbythekind permissionoftheauthorandGeorgeAllenandUnwin Ltd.,London. -31ticismratherthantoMill'ssupportofreceivedscientificdoctrines.At CambridgeIreadKantandHegel,aswellasMr.Bradley'sLogic, whichinfluencedmeprofoundly.ForsomeyearsIwasadiscipleof Mr.Bradley,butabout1898Ichangedmyviews,largelyasaresult ofargumentswithG.E.Moore.Icouldnolongerbelievethat knowingmakesanydifferencetowhatisknown.AlsoIfound myselfdriventopluralism.Analysisofmathematicalpropositions persuadedmethattheycouldnotbeexplainedasevenpartial truthsunlessoneadmittedpluralismandtherealityofrelations.An accidentledmeatthistimetostudyLeibniz,andIcametothe conclusion(subsequentlyconfirmedbyCouturat'smasterly researches)thatmanyofhismostcharacteristicopinionsweredue tothepurelylogicaldoctrinethateverypropositionhasasubject andapredicate.ThisdoctrineisonewhichLeibnizshareswith Spinoza,Hegel,andMr.Bradleyitseemedtomethat,ifitis rejected,thewholefoundationforthemetaphysicsofallthese philosophersisshattered.Ithereforereturnedtotheproblem whichhadoriginallyledmetophilosophy,namely,thefoundations ofmathematics,applyingtoitanewlogicderivedlargelyfrom PeanoandFrege,whichproved(atleast,soIbelieve)farmore fruitfulthanthatoftraditionalphilosophy. Inthefirstplace,Ifoundthatmanyofthestockphilosophical argumentsaboutmathematics(derivedinthemainfromKant)had beenrenderedinvalidbytheprogressofmathematicsinthe meanwhile.Non-Euclideangeometryhadunderminedtheargument ofthetranscendentalaesthetic.Weierstrasshadshownthatthe differentialandintegralcalculusdonotrequiretheconceptionof theinfinitesimal,andthat,therefore,allthathadbeensaidby philosophersonsuchsubjectsasthecontinuityofspaceandtime andmotionmustberegardedassheererror.Cantorfreedthe conceptionofinfinitenumberfromcontradiction,andthusdisposed ofKant'santinomiesaswellasmanyofHegel's.FinallyFrege showedindetailhowarithmeticcanbededucedfrompurelogic, withouttheneedofanyfreshideasoraxioms,thusdisproving Kant'sassertionthat"7+5=12"issynthetic--atleastinthe obviousinterpretationofthatdictum.Asalltheseresultswere obtained,notbyanyheroicmethod,butbypatientdetailed reasoning,Ibegantothinkitprobablethatphilosophyhaderredin

adoptingheroicremediesforintellectualdifficulties,andthat solutionswere tobefoundmerelybygreatercareandaccuracy. ThisviewIhavecometoholdmoreandmorestronglyastime wenton,andithasledmetodoubtwhetherphilosophy,asastudy distinctfromscienceand -32possessedofamethodofitsown,isanythingmorethanan unfortunatelegacyfromtheology. Frege'sworkwasnotfinal,inthefirstplacebecauseitappliedonly toarithmetic,nottootherbranchesofmathematicsinthesecond placebecausehispremisesdidnotexcludecertaincontradictionsto whichallpastsystemsofformallogicturnedouttobeliable.Dr. WhiteheadandIincollaborationtriedtoremedythesetwodefects, inPrincipiaMathematica,which,however,stillfallsshortoffinality insomefundamentalpoints(notablytheaxiomofreducibility).But inspiteofitsshortcomingsIthinkthatnoonewhoreadsthisbook willdisputeitsmaincontention,namely,thatfromcertainideasand axiomsofformallogic,bythehelpofthelogicofrelations,allpure mathematicscanbededuced,withoutanynewundefinedideaor unprovedpropositions.Thetechnicalmethodsofmathematical logic,asdevelopedinthisbook,seemtomeverypowerful,and capableofprovidinganewinstrumentforthediscussionofmany problemsthathavehithertoremainedsubjecttophilosophic vagueness.Dr.Whitehead'sConceptofNatureandPrinciplesof NaturalKnowledgemayserveasanillustrationofwhatImean. Whenpuremathematicsisorganizedasadeductivesystem-i.e.as thesetofallthosepropositionsthatcanbededucedfroman assignedsetofpremises--itbecomesobviousthat,ifweareto believeinthetruthofpuremathematics,itcannotbesolely becausewebelieveinthetruthofthesetofpremises.Someofthe premisesaremuchlessobviousthansomeoftheirconsequences, andarebelievedchieflybecauseoftheirconsequences.Thiswillbe foundtobealwaysthecasewhenascienceisarrangedasa deductivesystem.Itisnotthelogicallysimplestpropositionsofthe systemthatarethemostobvious,orthatprovidethechiefpartof ourreasonsforbelievinginthesystem.Withtheempiricalsciences thisisevident.Electro-dynamics,forexample,canbeconcentrated intoMaxwell'sequations,buttheseequationsarebelievedbecause oftheobservedtruthofcertainoftheirlogicalconsequences. Exactlythesamethinghappensinthepurerealmoflogicthe logicallyfirstprinciplesoflogic--atleastsomeofthem--are tobe believed,notontheirownaccount,butonaccountoftheir consequences.Theepistemologicalquestion:"WhyshouldIbelieve thissetofpropositions?"isquitedifferentfromthelogicalquestion: "Whatisthesmallestandlogicallysimplestgroupofpropositions fromwhichthissetofpropositionscanbededuced?"Ourreasons forbelievinglogicandpuremathematicsare,inpart,onlyinductive and -33-

probable,inspiteofthefactthat,intheirlogicalorder,the propositionsoflogicandpuremathematicsfollowfromthe premisesoflogicbypurededuction.Ithinkthispointimportant, sinceerrorsareliabletoarisefromassimilatingthelogicaltothe epistemologicalorder,andalso,conversely,fromassimilatingthe epistemologicaltothelogicalorder.Theonlywayinwhichworkon mathematicallogicthrowslightonthetruthorfalsehoodof mathematicsisbydisprovingthesupposedantinomies.Thisshows thatmathematicsmaybetrue.Buttoshowthatmathematicsis truewouldrequireothermethodsandotherconsiderations. OneveryimportantheuristicmaximwhichDr.WhiteheadandI found,byexperience,tobeapplicableinmathematicallogic,and havesinceappliedinvariousotherfields,isaformofOckham's razor.Whensomesetofsupposedentitieshasneatlogical properties,itturnsout,inagreatmanyinstances,thatthe supposedentitiescanbereplacedbypurelylogicalstructures composedofentitieswhichhavenotsuchneatproperties.Inthat case,ininterpretingabodyofpropositionshithertobelievedtobe aboutthesupposedentities,wecansubstitutethelogicalstructures withoutalteringanyofthedetailofthebodyofpropositionsin question.Thisisaneconomy,becauseentitieswithneatlogical propertiesarealwaysinferred,andifthepropositionsinwhichthey occurcanbeinterpretedwithoutmakingthisinference,theground fortheinferencefails,andourbodyofpropositionsissecured againsttheneedofadoubtfulstep.Theprinciplemaybestatedin theform:"Whereverpossible,substituteconstructionsoutofknown entitiesforinferencestounknownentities." Theusesofthisprincipleareveryvarious,butarenotintelligiblein detailtothosewhodonotknowmathematicallogic.Thefirst instanceIcameacrosswaswhatIhavecalled"theprincipleof abstraction,"or"theprinciplewhichdispenseswithabstraction."1 Thisprincipleisapplicableinthecaseofanysymmetricaland transitive relation,suchasequality.Weareapttoinferthatsuch relationsarisefrompossessionofsomecommonquality.Thismay ormaynotbetrueprobablyitistrueinsomecasesandnotin others.Butalltheformalpurposesofacommonqualitycanbe servedbymembershipofthegroupoftermshavingthesaid relationtoagiventerm.Takemagnitude,forexample.Letus supposethatwehaveagroupofrods,allequallylong.Itiseasyto supposethatthereisacertainquality,calledtheirlength,which theyallshare.Butallpropositionsinwhichthissupposedquality occurswill ____________________ 1OurKnowledge ofthe ExternalWorld,p.42. -34retaintheirtruth-value unchangedif,insteadof"lengthoftherod

x"wetake"membershipofthegroupofallthoserodswhichareas longasx."Invariousspecialcases--e.g.thedefinitionofreal numbers--asimplerconstructionispossible. AveryimportantexampleoftheprincipleisFrege'sdefinitionofthe cardinalnumberofagivensetoftermsastheclassofallsetsthat are"similar"tothegivenset--where twosetsare"similar"when thereisaone-onerelationwhosedomainistheonesetandwhose converse domainistheother.Thusacardinalnumberistheclass ofallthoseclasseswhicharesimilartoagivenclass.Thisdefinition leavesunchangedthetruth-valuesofallpropositionsinwhich cardinalnumbersoccur,andavoidstheinferencetoasetofentities called"cardinalnumbers,"whichwereneverneededexceptforthe purposeofmakingarithmeticintelligible,andarenownolonger neededforthatpurpose. Perhapsevenmoreimportantisthefactthatclassesthemselves canbedispensedwithbysimilarmethods.Mathematicsisfullof propositionswhichseemtorequirethataclassoranaggregate shouldbeinsomesenseasingleentity--e.g.theproposition"the numberofcombinationsofnthingsanynumberatatimeis2n." Since2nisalwaysgreaterthann,thispropositionleadsto difficultiesifclassesareadmittedbecausethenumberofclassesof entitiesintheuniverseisgreaterthanthenumberofentitiesinthe universe,whichwouldbeoddifclasseswere someamongentities. Fortunatelyallthepropositionsinwhichclassesappeartobe mentionedcanbeinterpretedwithoutsupposingthatthereare classes.Thisisperhapsthemostimportantofalltheapplicationsof ourprinciple.(See PrincipiaMathematica,*20.) AnotherimportantexampleconcernswhatIcall"definite descriptions,"i.e.suchphrasesas"theevenprime,""thepresent KingofEngland,""thepresentKingofFrance."Therehasalways beenadifficultyininterpretingsuchpropositionsas"thepresent KingofFrance doesnotexist."Thedifficultyarosethrough supposingthat"thepresentKingofFrance"isthesubjectofthis proposition,whichmadeitnecessarytosupposethathesubsists althoughhedoesnotexist.Butitisdifficulttoattributeeven subsistenceto"theroundsquare"or"theevenprimegreaterthan 2."Infact,"theroundsquaredoesnotsubsist"isjustastrueas "thepresentKingofFrancedoesnotexist."Thusthedistinction betweenexistenceandsubsistencedoesnothelpus.Thefactis that,whenthewords"theso-and-so"occurinaproposition,there isnocorrespondingsingleconstituentoftheproposition,andwhen thepropositionis -35fullyanalyzedthewords"theso-and-so"havedisappeared.An importantconsequenceofthetheoryofdescriptionsisthatitis meaninglesstosay"Aexists"unless"A"is(orstandsfor)aphrase oftheform"theso-and-so."Iftheso-and-soexists,andxisthe so-and-so,tosay"xexists"isnonsense.Existence,inthesensein

whichitisascribedtosingleentities,isthusremovedaltogether fromthelistoffundamentals.Theontologicalargumentandmost ofitsrefutationsarefoundtodependuponbadgrammar.(See PrincipiaMathematica,*14.) Therearemanyotherexamplesofthesubstitutionofconstructions forinferencesinpuremathematics,forexample,series,ordinal numbers,andrealnumbers.ButIwillpassontotheexamplesin physics. Pointsandinstantsareobviousexamples:Dr.Whiteheadhas shownhowtoconstructthemoutofsetsofeventsallofwhichhave afiniteextentandafiniteduration.Inrelativitytheory,itisnot pointsorinstantsthatweprimarilyneed,butevent-particles,which correspondtowhat,inolderlanguage,mightbedescribedasa pointataninstant,oraninstantaneouspoint.(Informerdays,a pointofspaceenduredthroughoutalltime,andaninstantoftime pervadedallspace.Nowtheunitthatmathematicalphysicswants hasneitherspatialnortemporalextension.)Event-particlesare constructedbyjustthesamelogicalprocessbywhichpointsand instantswere constructed.Insuchconstructions,however,weare onadifferentplanefromthatofconstructionsinpure mathematics.Thepossibilityofconstructinganevent-particle dependsupontheexistenceofsetsofeventswithcertain propertieswhethertherequiredeventsexistcanonlybeknown empirically,ifatall.Thereisthereforenoapriorireasontoexpect continuity(inthemathematicalsense),ortofeelconfidentthat event-particlescanbeconstructed.Ifthequantumtheoryshould seemtodemandadiscretespace-time,ourlogicisjustasreadyto meetitsrequirementsastomeetthoseoftraditionalphysics,which demandscontinuity.Thequestionispurelyempirical,andourlogic is(asitoughttobe)equallyadaptedtoeitheralternative. Similarconsiderationsapplytoaparticleofmatter,ortoapieceof matteroffinitesize.Matter,traditionally,hastwoofthose"neat" propertieswhicharethemarkofalogicalconstructionfirst,that twopiecesofmattercannotbeatthesameplaceatthesame timesecondly,thatonepieceofmattercannotbeintwoplacesat thesametime.Experienceinthesubstitutionofconstructionsfor inferencesmakesonesuspiciousofanythingsotidyandexact.One -36cannothelpfeelingthatimpenetrabilityisnotanempiricalfact, derivedfromobservationofbilliard-balls,butissomethinglogically necessary.Thisfeelingiswhollyjustified,butitcouldnotbesoif matterwere notalogicalconstruction.Animmensenumberof occurrencescoexistinanylittleregionofspace-timewhenweare speakingofwhatisnotlogicalconstruction,wefindnosuch propertyasimpenetrability,but,onthecontrary,endless overlappingoftheeventsinapartofspace-time,howeversmall. Thereasonthatmatterisimpenetrableisbecauseourdefinitions makeitso.Speakingroughly,andmerelysoastogiveanotionof howthishappens,wemaysaythatapieceofmatterisallthat

happensinacertaintrackinspace-time,andthatweconstructthe trackscalledbitsofmatterinsuchawaythattheydonotintersect. Matterisimpenetrablebecauseitiseasiertostatethelawsof physicsifwemakeourconstructionssoastosecure impenetrability.Impenetrabilityisalogicallynecessaryresultof definition,thoughthefactthatsuchadefinitionisconvenientis empirical.Bitsofmatterarenotamongthebricksoutofwhichthe worldisbuilt.Thebricksareevents,andbitsofmatterareportions ofthestructure towhichwefinditconvenienttogiveseparate attention. Inthephilosophyofmentaloccurrencestherearealso opportunitiesfortheapplicationofourprincipleofconstructions versusinferences.Thesubject,andtherelationofacognitionto whatisknown,bothhavethatschematicqualitythatarousesour suspicions.Itisclearthatthesubject,ifitistobepreservedatall, mustbepreservedasaconstruction,notasaninferredentitythe onlyquestioniswhetherthesubjectissufficientlyusefultobe worthconstructing.Therelationofacognitiontowhatisknown, again,cannotbeastraightforwardsingleultimate,asIatonetime believedittobe.AlthoughIdonotagreewithpragmatism,Ithink WilliamJameswasrightindrawingattentiontothecomplexityof "knowing."Itisimpossibleinageneralsummary,suchasthe present,tosetoutthereasonsforthisview.Butwhoeverhas acquiescedinourprinciplewillagreethathereisprimafacieacase forapplyingit.MostofmyAnalysisofMindconsistsofapplications ofthisprinciple.Butaspsychologyisscientificallymuchless perfectedthanphysics,theopportunitiesforapplyingtheprinciple arenotsogood.Theprincipledepends,foritsuse,uponthe existenceofsomefairlyreliablebodyofpropositions,whichareto beinterpretedbythelogicianinsuchawayastopreserve their truthwhileminimizingtheelementofinferencetounobserved entities.Theprinciplethereforepresupposesamoderately advancedscience,intheabsence -37ofwhichthelogiciandoesnotknowwhatheoughttoconstruct. Untilrecently,itwouldhaveseemednecessarytoconstruct geometricalpointsnowitisevent-particlesthatarewanted.In viewofsuchachangeinanadvancedsubjectlikephysics,itisclear thatconstructionsinpsychologymustbepurelyprovisional. Ihavebeenspeakinghithertoofwhatitisnotnecessarytoassume aspartoftheultimateconstituentsoftheworld.Butlogical constructions,likeallotherconstructions,require materials,anditis timetoturntothepositivequestion,astowhatthesematerialsare tobe.Thisquestion,however,requiresasapreliminarya discussionoflogicandlanguageandtheirrelationtowhattheytry torepresent. Theinfluenceoflanguageonphilosophyhas,Ibelieve,been profoundandalmostunrecognized.Ifwearenottobemisledby thisinfluence,itisnecessarytobecomeconsciousofit,andtoask

ourselvesdeliberatelyhowfaritislegitimate.Thesubjectpredicate logic,withthesubstance-attribute metaphysic,areacaseinpoint. Itisdoubtfulwhethereitherwouldhavebeeninventedbypeople speakinganon-Aryanlanguagecertainlytheydonotseemtohave ariseninChina,exceptinconnectionwithBuddhism,whichbrought Indianphilosophywithit.Again,itisnatural,totakeadifferent kindofinstance,tosupposethatapropernamewhichcanbeused significantlystandsforasingleentitywesupposethatthereisa certainmoreorlesspersistentbeingcalled"Socrates,"becausethe samenameisappliedtoaseriesofoccurrenceswhichweareled toregardasappearancesofthisonebeing.Aslanguagegrows moreabstract,anewsetofentitiescomeintophilosophy,namely, thoserepresentedbyabstractwords--the universals.Idonotwish tomaintainthattherearenouniversals,butcertainlythereare manyabstractwordswhichdonotstandforsingleuniversals--e.g. triangularityandrationality.Intheserespectslanguagemisleadsus bothbyitsvocabularyandbyitssyntax.Wemustbeonourguard inbothrespectsifourlogicisnottoleadtoafalsemetaphysic. Syntaxandvocabularyhavehaddifferentkindsofeffectson philosophy.Vocabularyhasmostinfluenceoncommonsense.It mightbeurged,conversely,thatcommonsenseproducesour vocabulary.Thisisonlypartiallytrue.Awordisappliedatfirstto thingswhicharemoreorlesssimilar,withoutanyreflectionasto whethertheyhaveanypointofidentity.Butwhenonceusagehas fixedtheobjectstowhichthewordistobeapplied,commonsense isinfluencedbytheexistenceoftheword,andtendstosup-38posethatonewordmuststandforoneobject,whichwillbea universalinthecaseofanadjectiveoranabstractword.Thusthe influenceofvocabularyistowardsakindofplatonicpluralismof thingsandideas. Theinfluenceofsyntax,inthecaseoftheIndo-European languages,isquitedifferent.Almostanypropositioncanbeputinto aforminwhichithasasubjectandapredicate,unitedbya copula.Itisnaturaltoinferthateveryfacthasacorresponding form,andconsistsinthepossessionofaqualitybyasubstance. Thisleads,ofcourse,tomonism,sincethefactthattherewere severalsubstances(ifitwere afact)wouldnothavetherequisite form.Philosophers,asarule,believethemselvesfreefromthis sortofinfluenceoflinguisticforms,butmostofthemseemtome tobemistakeninthisbelief.Inthinkingaboutabstractmatters,the factthatthewordsforabstractionsarenomoreabstractthan ordinarywordsalwaysmakesiteasiertothinkaboutthewords thanaboutwhattheystandfor,anditisalmostimpossibletoresist consistentlythetemptationtothinkaboutthewords. Thosewhodonotsuccumbtothesubject-predicatelogicareaptto getonlyonestepfurther,andadmitrelationsoftwoterms,suchas before-and-after,greater-and-less,right-and-left.Languagelends itselftothisextensionofthesubject-predicatelogic,sincewesay

'"AprecedesB,""AexceedsB,"andsoon.Itiseasytoprovethat thefactexpressedbyapropositionofthissortcannotconsistofthe possessionofaqualitybyasubstance,orofthepossessionoftwo ormorequalitiesbytwoormoresubstances.(See Principlesof Mathematics,214.)Theextensionofthesubject-predicatelogicis therefore rightsofarasitgoes,butobviouslyafurtherextension canbeprovednecessarybyexactlysimilararguments.Howfaritis necessarytogouptheseriesofthreeterm,four-term,five-term.. .relationsIdonotknow.Butitiscertainlynecessarytogobeyond two-termrelations.Inprojectivegeometry,forexample,theorder ofpointsonalineorofplanesthroughalinerequiresafour-term relation. Averyunfortunateeffectofthepeculiaritiesoflanguageisin connectionwithadjectivesandrelations.Allwordsareofthesame logicaltypeawordisaclassofseries,ofnoisesorshapes accordingasitisheardorread.Butthemeaningsofwordsareof variousdifferenttypesanattribute(expressedbyanadjective)is ofadifferenttypefromtheobjectstowhichitcanbe(whether trulyorfalsely)attributedarelation(expressedperhapsbya preposition,perhapsbyatransitiveverb,perhapsinsomeother way)is -39ofadifferenttypefromthetermsbetweenwhichitholdsordoes nothold.Thedefinitionofalogicaltypeisasfollows:AandBare ofthesamelogicaltypeif,andonlyif,givenanyfactofwhichAis aconstituent,thereisacorrespondingfactwhichhasBasa constituent,whicheitherresultsbysubstitutingBforA,oristhe negationofwhatsoresults.Totakeanillustration,Socratesand Aristotle areofthesametype,because"Socrateswasa philosopher"and"Aristotle wasaphilosopher"arebothfacts SocratesandCaligulaareofthesametype,because"Socrateswas aphilosopher"and"Caligulawasnotaphilosopher"arebothfacts. Toloveandtokillareofthesametype,because"Platoloved Socrates"and"PlatodidnotkillSocrates"arebothfacts.Itfollows formallyfromthedefinitionthat,whentwowordshavemeanings ofdifferenttypes,therelationsofthewordstowhattheymeanare ofdifferenttypesthatistosay,thereisnotonerelationof meaningbetweenwordsandwhattheystandfor,butasmany relationsofmeaning,eachofadifferentlogicaltype,asthereare logicaltypesamongtheobjectsforwhichtherearewords.Thisfact isaverypotentsourceoferrorandconfusioninphilosophy.In particular,ithasmadeitextraordinarilydifficulttoexpressinwords anytheoryofrelationswhichislogicallycapableofbeingtrue, becauselanguagecannotpreserve thedifferenceoftypebetween arelationanditsterms.Mostoftheargumentsforandagainstthe realityofrelationshavebeenvitiatedthroughthissourceof confusion. Atthispoint,Iproposetodigressforamoment,andtosay,as shortlyasIcan,whatIbelieveaboutrelations.Myownviewson

thesubjectofrelationsinthepastwere lessclearthanIthought them,butwere bynomeanstheviewswhichmycriticssupposed themtobe.Owingtolackofclearnessinmyownthoughts,Iwas unabletoconveymymeaning.Thesubjectofrelationsisdifficult, andIamfarfromclaimingtobenowclearaboutit.ButIthink certainpointsarecleartome.AtthetimewhenIwroteThe PrinciplesofMathematics,Ihadnotyetseenthenecessityoflogical types.Thedoctrineoftypesprofoundlyaffectslogic,andIthink showswhat,exactly,isthevalidelementintheargumentsofthose whooppose"external"relations.Butsofarfromstrengtheningtheir mainposition,thedoctrineoftypesleads,onthecontrary,toa morecompleteandradicalatomismthananythatIconceivedtobe possibletwentyyearsago.Thequestionofrelationsisoneofthe mostimportantthatariseinphilosophy,asmostotherissuesturn onit:monismandpluralismthequestionwhetheranythingis whollytrueexceptthewholeoftruth,orwhollyrealexceptthe -40wholeofrealityidealismandrealism,insomeoftheirforms perhapstheveryexistenceofphilosophyasasubjectdistinctfrom scienceandpossessingamethodofitsown.Itwillservetomake mymeaningclearifItakeapassageinMr.Bradley'sEssayson TruthandReality,notforcontroversialpurposes,butbecauseit raisesexactlytheissuesthatoughttoberaised.ButfirstofallIwill trytostatemyownview,withoutargument.2 Certaincontradictions--ofwhichthesimplestandoldestistheone aboutEpimenidestheCretan,whosaidthatallCretanswereliars, whichmaybereducedtothemanwhosays"Iamlying"-convinced me,afterfiveyearsdevotedmainlytothisonequestion,thatno solutionistechnicallypossiblewithoutthedoctrineoftypes.Inits technicalform,thisdoctrinestatesmerelythatawordorsymbol mayformpartofasignificantproposition,andinthissensehave meaning,withoutbeingalwaysabletobesubstitutedforanother wordorsymbolinthesameorsomeotherpropositionwithout producingnonsense.Statedinthisway,thedoctrinemayseemlike atruism."BrutuskilledCaesar"issignificant,but"Killedkilled Caesar"isnonsense,sothatwecannotreplace"Brutus"by"killed," althoughbothwordshavemeaning.Thisisplaincommonsense, butunfortunatelyalmostallphilosophyconsistsinanattemptto forgetit.Thefollowingwords,forexample,bytheirverynature, sinagainstit:attribute,relation,complex,fact,truth,falsehood, not,liar,omniscience.Togiveameaningtothesewords,wehave tomakeadetourbywayofwordsorsymbolsandthedifferent waysinwhichtheymaymeanandeventhen,weusuallyarrive, notatonemeaning,butataninfiniteseriesofdifferentmeanings. Words,aswesaw,areallofthesamelogicaltypethereforewhen themeaningsoftwowordsareofdifferenttypes,therelationsof thetwowordstowhattheystandforarealsoofdifferenttypes. Attribute-wordsandrelation-wordsareofthesametype,therefore wecansaysignificantly"attribute-wordsandrelationwordshave differentuses."Butwecannotsaysignificantly"attributesarenot

relations."Byourdefinitionoftypes,sincerelationsarerelations, theformofwords"attributesarerelations"mustbenotfalse,but meaningless,andtheformofwords"attributesarenotrelations," similarly,mustbenottrue,butmeaningless.Nevertheless,the statement"attribute-wordsarenotrelation-words"issignificantand true. ____________________ 2Iam muchindebtedtomyfriendWittgensteininthismatter.See hisTractatusLogico-Philosophicus,KeganPaul,1922.Idonot acceptallhisdoctrines,butmydebttohimwillbeobviousto thosewhoreadhisbook. -41Wecannowtacklethequestionofinternalandexternalrelations, rememberingthattheusualformulations,onbothsides,are inconsistentwiththedoctrineoftypes.Iwillbeginwithattemptsto statethedoctrineofexternalrelations.Itisuselesstosay"terms areindependentoftheirrelations,"because"independent"isa wordwhichmeansnothing.Twoeventsmaybesaidtobecausally independentwhennocausalchainleadsfromonetotheotherthis happens,inthespecialtheoryofrelativity,whentheseparation betweentheeventsisspace-like.Obviouslythissenseof "independent"isirrelevant.If,whenwesay"termsare independentoftheirrelations,"wemean"twotermswhichhavea givenrelationwouldbethesameiftheydidnothaveit,"thatis obviouslyfalsefor,beingwhattheyare,theyhavetherelation, andtherefore whateverdoesnothavetherelationisdifferent.If wemean--asopponentsofexternalrelationssupposeustomean-thattherelationisathirdtermwhichcomesbetweenthe