{ONE}
THEMATTEROFMIND
Natureinherunfathomabledesignshasmixedusofclayandflame,ofbrainandmind,thatthe
twothingshangindubitablytogetheranddetermineeachother’sbeing,buthoworwhy,no
mortalmayeverknow.
—WilliamJames
PrinciplesofPsychology,ChapterVI
Whatismind?Nomatter.Whatismatter?Nevermind.
—T.H.Key
Ofallthethousandsofpagesandmillionsofwordsdevotedtothepuzzleofthemindandthe
brain,tothemysteryofhowsomethingassublimeandinsubstantialasthoughtor
consciousnesscanemergefromthreepoundsofgelatinouspuddinginsidetheskull,myfavorite
statementoftheproblemisnotthatofoneofthegreatphilosophersofhistory,butofascience
fictionwriter.Inashortstoryfirstpublishedinthescienceandsci-fimagazineOmniin1991,
theHugo-winningauthorTerryBissongetsrighttotheheartoftheutterabsurdityofthe
situation:thatanorganmadefrombasicallythesamematerialingredients(nucleated,carbonbased,mitochondria-filledcells)as,say,akidney,isabletogeneratethisineffablethingcalled
mind.Bisson’sstorybeginswiththisconversationbetweenanaliencommanderandascout
whohasjustreturnedfromEarthtoreporttheresultsofhisreconnaissance:
“They’remadeoutofmeat.”
“Meat?”
“There’snodoubtaboutit.Wepickedseveralfromdifferentpartsoftheplanet,tookthem
aboardourreconvessels,probedthemallthewaythrough.They’recompletelymeat.”
“That’simpossible.Whatabouttheradiosignals?Themessagestothestars?”
“Theyusetheradiowavestotalk,butthesignalsdon’tcomefromthem.Thesignalscome
frommachines.”
“Sowhomadethemachines?That’swhowewanttocontact.”
“Theymadethemachines.That’swhatI’mtryingtotellyou.Meatmadethemachines.”
“That’sridiculous.Howcanmeatmakeamachine?You’reaskingmetobelieveinsentient
meat.”
“I’mnotaskingyou,I’mtellingyou.Thesecreaturesaretheonlysentientraceinthesector
andthey’remadeofmeat.”
“Maybethey’reliketheOrfolei.Youknow,acarbon-basedintelligencethatgoesthrough
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ameatstage.”
“Nope.They’rebornmeatandtheydiemeat.Westudiedthemforseveraloftheir
lifespans,whichdidn’ttaketoolong.Doyouhaveanyideaofthelifespanofmeat?”
“Spareme.Okay,maybethey’reonlypartmeat.Youknow,liketheWeddilei.Ameat
headwithanelectronplasmabraininside.”
“Nope,wethoughtofthat,sincetheydohavemeatheadsliketheWeddilei.ButItoldyou,
weprobedthem.They’remeatallthewaythrough.”
“Nobrain?”
“Oh,thereisabrainallright.It’sjustthatthebrainismadeoutofmeat.”
“So…whatdoesthethinking?”
“You’renotunderstanding,areyou?Thebraindoesthethinking.Themeat.”
“Thinkingmeat!You’reaskingmetobelieveinthinkingmeat!”
“Yes,thinkingmeat!Consciousmeat!Lovingmeat.Dreamingmeat.Themeatisthewhole
deal!Areyoubeginningtogetthepicture,ordoIhavetostartallover?”
Itwassome2,500yearsagothatAlcmaeonofCroton,anassociateofthePythagorean
schoolofphilosophywhoisregardedasthefounderofempiricalpsychology,proposedthat
consciousexperienceoriginatesinthestuffofthebrain.Arenownedmedicalandphysiological
researcher(hepracticedsystematicdissection),Alcmaeonfurthertheorizedthatallsensory
awarenessiscoordinatedbythebrain.Fiftyyearslater,Hippocratesadoptedthisnotionofthe
brainastheseatofsensation,writinginhistreatiseonseizures:“Iconsiderthatthebrainhas
themostpowerforman….Theeyesandearsandtongueandhandsandfeetdowhatsoeverthe
braindetermines…itisthebrainthatisthemessengertotheunderstanding[and]thebrainthat
interpretstheunderstanding.”AlthoughAristotleandtheStoicsrejectedthisfinding(seating
thoughtintheheartinstead),todayscientistsknow,asmuchastheyknowanything,thatallof
mentallifespringsfromneuronalprocessesinthebrain.Thisbeliefhasdominatedstudiesof
mind-brainrelationssincetheearlynineteenthcentury,whenphrenologistsattemptedto
correlatethevariousknobsandbumpsontheskullwithoneoranotherfacetofpersonalityor
mentalability.Today,ofcourse,thosecorrelationsareabitmoreprecise,asscientists,going
beyondthephrenologists’conclusionthatthirty-sevenmentalfacultiesarerepresentedonthe
surfaceoftheskull,dotheirmappingwithbrainimagingtechnologiessuchaspositron
emissiontomography(PET)andfunctionalmagneticresonanceimaging(fMRI),which
pinpointwhichbrainneighborhoodsareactiveduringanygivenmentalactivity.
Thishasbeenoneofthegreatesttriumphsofmodernneuroscience,thismappingofwhole
worldsofconsciousexperience—fromrecognizingfacestofeelingjoy,fromfingeringaviolin
stringtosmellingaflower—ontoaparticularclusterofneuronsinthebrain.Itbeganinthe
1950s,whenWilderPenfield,apioneerintheneurosurgeryofepilepsy,electricallystimulated
tinyspotsonthesurfaceofpatients’brains(apainlessprocedure,sinceneuronshaveno
feeling).Thepatientswerefloodedwithlong-forgottenmemoriesoftheirgrandmotherorheard
atunesovividlythattheyaskedthegooddoctorwhyaphonographwasplayinginthe
operatingtheater.Butitisnotmerelytheprecisionofthementalmapsthathasincreasedwith
theintroductionofelectrodes—andlaternoninvasivebrainimaging—toreplacetheskull-bump
cartographybelovedofphrenologists.Sohasneuroscientists’certaintythattracingdifferent
mentalabilitiestospecificregionsinthebrain—verbalworkingmemorytoaspotbeneaththe
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onthemind-matterenigma.TheCanadianneurosurgeonWilderPenfield,afteralongcareer
dedicatedtoexplainingthematerialbasisofmind,intheenddecidedthatbrain-related
explanationsareintrinsicallyinsufficient.CharlesSherrington,thefounderofmodern
neurophysiology,contendedin1947thatbrainprocessesalonecannotaccountforthefullrange
ofsubjectivementalphenomena,includingconsciousfreewill.“Thatourbeingshouldconsist
oftwofundamentalelementsoffers,Isuppose,nogreaterinherentimprobabilitythanthatit
shouldrestononeonly,”hewrote.OneofSherrington’sgreatestpupils,SirJohnEccles,held
similarviews.EccleswonaNobelPrizeforhisseminalcontributionstoourunderstandingof
hownervecellscommunicateacrosssynapses,ornervejunctions.Inhislateryears,heworked
towardadeeperunderstandingofthemechanismsmediatingtheinteractionofmindandbrain
—includingtheelusivenotionoffreewill.Standardneurobiologytellsusthattinyvesiclesin
thenerveendingscontainchemicalscalledneurotransmitters;inresponsetoanelectrical
impulse,someofthevesiclesreleasetheircontents,whichcrossthesynapseandtransmitthe
impulsetotheadjoiningneuron.In1986Ecclesproposedthattheprobabilityof
neurotransmitterreleasedependedonquantummechanicalprocesses,whichcanbeinfluenced
bytheinterventionofthemind.This,Ecclessaid,providedabasisfortheactionofafreewill.
ItisfairtosaythatthedebateinstigatedbyDescartesoverthemind-bodyproblemhasnot
endedatall;ithasinsteadbecomealmostpainfullysophisticatedandcomplex.Amongthe
warringtheoriesinplaytodaywehave(inonecontemporaryrundown)“theidentitytheory,the
centralstatetheory,neutralmonism,logicalbehaviorism,tokenphysicalismandtype
physicalism,tokenepiphenomenalismandtypeepiphenomenalism,anomalousmonism,
emergentmaterialism,eliminativematerialism,variousbrandsoffunctionalism”—and,
undoubtedly,enoughadditionalismstoassignonetoeveryworkingphilosopherintheworld.
Afewwordsonasmallhandfulofthesephilosophiesofmindandmatter(listedfrommostto
leastmaterialistic)shouldcapturetheflavorofthedebateandgiveasenseofthecompeting
ideas.
FUNCTIONALISM,or“MentalisticMaterialism”astheneurosurgeonJoeBogenhas
termedit,deniesthatthemindisanythingmorethanbrainstates;itisamerebyproductofthebrain’sphysicalactivity.AsthephilosopherOwenFlanaganputsit,
“Mentalprocessesarejustbrainprocesses,”andunderstandingwhatthosebrain
processesareandhowtheyworktellsusallthereistoknowaboutwhatmindis.
Thisviewrecognizesonlymaterialinfluences.PaulandPatriciaChurchlandand
DanielDennettareleadingadvocatesofsuchmaterialistviews,whichareclosely
akintobehaviorism.Thematerialistpositiongoessofarastodenytheultimate
realityofmental“events”likeourcolor-blindscientist’ssuddenexperienceofthe
rednessofapeony,aswellastheactualfactofconsciousnessitself.Otherthanthe
actionpotentialscoursingthroughbraincircuits,theyinsist,thereisnothingmoreto
theworkingsofthemind—atleast,nothingthatscienceneedstoaddress.Ifwehold
tenaciouslytosuchquaintnotionsasexperientialreality,consciousness,andthe
ontologicalvalidityofqualia,itisonlyoutofignorance:oncescienceparsesthe
actionsofthebraininsufficientdetail,qualiaandconsciousnesswillevaporatejust
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asthe“vitalspark”didbeforebiologistsnaileddownthenatureoflivingthings.
Materialismcertainlyhasonethinggoingforit.Bydenyingtheexistenceof
consciousnessandothermentalphenomena,itneatlymakesthemind-matter
problemdisappear.Nomind,allmatter—nomind-matterproblem.
EPIPHENOMENALISMacknowledgesthatmindisarealphenomenonbutholdsthatit
cannothaveanyeffectonthephysicalworld.Thisschoolacknowledgesthatmind
andmatteraretwoseparatebeasts,asarephysicaleventsandmentalevents,but
onlyinthesensethatqualiaandconsciousnessarenotstrictlyreducibletoneuronal
events,anymorethanthepropertiesofwaterarereducibletothechemical
characteristicsofoxygenandhydrogen.Fromthisperspective,consciousnessisan
epiphenomenonofneuronalprocesses.Epiphenomenalismviewsthebrainasthe
causeofallaspectsofthemind,butbecauseitholdsthatthephysicalworldis
causallyclosed—thatis,thatphysicaleventscanhaveonlyphysicalcauses—it
holdsthattheminditselfdoesn’tactuallycauseanythingtohappenthatthebrain
hasn’talreadytakencareof.Itthusleavesuswitharatherwitheredsortofmind,
oneinwhichconsciousnessis,atleastinscientificterms,reducedtoanimpotent
shadowofitsformerself.Asanonphysicalphenomenon,itcannotactonthe
physicalworld.Itcannotmakestuffhappen.Itcannot,say,makeanarmmove.
Epiphenomenalismholdsthatthebrainisthecauseofallthementaleventsinthe
mindbutthattheminditselfisnotthecauseofanything.Becauseitmaintainsthat
thecausalarrowpointsinonlyonedirection,frommaterialtomental,thisschool
deniesthecausalefficacyofmentalstates.Itthereforefindsitselfrightathome
withthefundamentalassumptionofmaterialistscience,certainlyasappliedto
psychologyandnowneuroscience,that“minddoesnotmovematter,”asthe
neurologistC.J.Herrickwrotein1956.Putanotherway,allphysicalactioncanbe
buttheconsequenceofanotherphysicalaction.Thesensethatwillandothermental
statescanmovematter—eventhematterthatmakesupone’sownbody—is
therefore,intheviewoftheepiphenomenalists,anillusion.
Althoughepiphenomenalismisoftenregardedthesedaysastheonlygenerally
acceptablealternativetostarkmaterialism,oneproblemwiththispositionisthatit
contradictsourbasiccoreexperiencethatmentalstatesreallydoaffectouractions.
Todenythecausalefficacyofmentalstatesaltogetheristodismisstheexperience
ofwilledactionasnothingbutanillusion.Anothercriticalproblemwith
epiphenomenalism(andotherschoolsthatdenythecausalefficacyofmind)was
raisedin1890bythepsychologistandphilosopherWilliamJames.Thebasic
principlesofevolutionarybiologywouldseemtodictatethatanynatural
phenomenonasprominentinourlivesasourexperienceofconsciousnessmust
necessarilyhavesomediscernibleandquantifiableeffectinorderforittoexist,and
topersist,innatureatall.Itmust,inotherwords,confersomeselectiveadvantage.
Andthatraisesanobviousquestion:Whatpossibleselectiveadvantagecould
consciousnessofferifitisonlyafunctionlessphantasm?Howcouldconsciousness
everhaveevolvedinthefirstplaceif,inandofitself,itdoesnothing?Why,in
short,didnaturebothertoproducebeingscapableofself-awarenessandsubjective,
innerexperience?True,evolutionarybiologistscantrotoutmanyexamplesoftraits
thathavebeencarriedalongontheriverofevolutionalthoughnotspecifically
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selectedfor(theevolutionarybiologistsStephenJayGouldandRichardLewontin
calledsuchtraitsspandrels,thearchitecturaltermfortheelementsbetweenthe
exteriorcurveofanarchandtherightangleofthewallsaroundit,whichwerenot
intention-allybuiltbutwereinsteadformedbytwoarchitecturaltraitsthatwere
“selectedfor”).Butconsciousnessseemslikeanawfullyprominenttraitnottohave
beenthetargetofsomeselectionpressure.AsJamesputit,“Theconclusionthat
[consciousness]isusefulis…quitejustifiable.Butifitisuseful,itmustbeso
throughitscausalefficaciousness.”
EMERGENTMATERIALISMarguesthatmindarisesfrombraininawaythatcannotbe
fullypredictedfromorreducedtobrainprocesses.Theattributesofmind,thatis,
cannotbeexplainedsolelybybrain’sphysicalactivity.Further,accordingtothis
view,mindmayhavethepowertoeffectbothmentalandphysicalchange.
EmergentistslikeSteenRasmussensuggestthat,sometimes,ahigh-order,emergent
propertylikemindhasthepowertoexertaneffectonthelower-orderprocessesthat
createdit.Inotherwords,whatemergescanaffectwhatitemergesfrom.
TheNobel-winningneuroscientistRogerSperrytaughtattheCaliforniaInstitute
ofTechnologyfrom1954untilhisdeathin1994.Bestknownforhisstudyof“split
brain”patients(manyofwhosesurgeriesseveringtheconnectionsbetweentheright
andleftcerebralhemisphereswereactuallyperformedbyJoeBogen),Sperry
producedthemostdetailedandscientificallybasedversionofemergent
materialism.Hevariouslycalledhisownemergenttheory“mentalism,”“emergent
mentalism,”orjust“thenewmentalism.”Atfirst,hearguedonlythatmindisnot
reducibletocerebralactivity,echoingthemainstreamemergentpositionthatmind
arisesfrombrainasauniqueentitywhoseattributesandpowercannotbepredicted,
orevenexplained,fromitsmaterialcomponentsalone.ButlaterSperrybecame
uneasywiththetriumphofmaterialisminneuroscienceandwhathecalledits
“exclusive‘bottom-up’determinationofthewholebytheparts,inwhichthe
neuronaleventsdeterminethementalbutnotviceversa.”Asaresulthelater
espousedaviewthatmentalstatescanindeedhavecausalefficacy.Incontrastto
agnosticphysicalism(discussedlater),whichallowsmentalstatestoinfluenceother
mentalstatesonlythroughtheintermediaryofthebrain,emergentmaterialism
grantstosomementalstatesthepowerdirectlytochange,shape,orbringintobeing
othermentalstates,aswellastoactbackoncerebralstates.Intheyearsjustbefore
hisdeath,Sperryhintedthatmentalforcescouldcausallyshapetheelectrochemical
activityofneurons.
Thisrepresentedaradicalnewvisionofthecausalrelationsbetweenhigherordermentalprocessesandneuronalevents.WhatSperrytermed“mentalforces”
could,heargued,directtheelectrochemicaltrafficbetweenneuronsatthecellular
level.Thisviewthusarguesthatemergentmentalpropertiescanexerttop-down
causalcontrolovertheircomponentparts—“thedownwardcontrolbymental
eventsoverthelowerneuronalevents.”This,aswewillseeinChapter2,describes
verywellthecontrolbyanOCDpatient’smindofhisneuronalevents,specifically
theactivityinthepathologicalcircuitsunderlyingthedisease.Sperrywasatpains
topointoutthathisbeliefdidnotconstitutedualism(thatdreadedword!)inany
Cartesiansense,butratheraradicallyrevisedformofmaterialisminwhichthe
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mindisnotonlyemergentbutalsocausal.Hemaintained(asclassical,non-sciencebaseddualistsdonot)thatthemyriadconsciousexperiencescannotexistapartfrom
thebrain;hedidnotpositanunembodiedmindorconsciousnessas,again,classical
dualistsdo.Thementalforcesheconsideredcausallyefficaciouswerenospooky,
nonmaterial,preternaturalentities.Asheputitin1970,“Theterm[mentalforces]
…doesnotimplyhereanydisembodiedsupernaturalforcesindependentofthe
brainmechanism.Thementalforcesashereconceivedareinseparablytiedtothe
cerebralstructureanditsfunctionalorganization.”Theyshapeanddirectthelowerleveltrafficofelectricalimpulses.TheformofcausalefficacySperryproposedwas
onethatadherentsofmaterialist,bottom-updeterminismdismissed—namely,one
inwhich“higher-level”mentalpropertiesexertcausalcontroloverthe“lower
level”ofneuronsandsynapses.Inthisscheme,Sperrywrotein1965,“thecausal
potencyofanidea,oranideal,becomesjustasrealasthatofamolecule,acell,ora
nerveimpulse.”Heferventlyhopedthatthenewviewofmindwouldintegrate
“traditionallyconflictingpositionsonmindandmatter,thementalversusthe
material,”andthat“scienceasawholemaybeintheprocessofshiftingawayfrom
itscenturies-oldmicrodeterminatematerialistparadigmtoamorevalid
macromentalmodelforcausalexplanationandunderstanding.”
NotevenaNobelPrizeofferedadequateshieldingfromthebrickbatshurledat
Sperryforthisplungeintothemind-and-matterwars.WhentheEnglish
psychologistOliverZangwillvisitedCaltechinAugust1970,asJoeBogen
recounts,heexpressedtoSperryhisconcernthatif“Sperrywentoninthisveinitis
likelytodiminishtheimpactofhismanymarvelousachievements.”How,Bogen
asked,didSperryreact?Verylittle,repliedZangwill.Fromabout1980,almostall
ofSperry’swritingswereaboutconsciousnessandmentalforcesactingfromthe
topdown.WhenhewashonoredatCaltechin1982ontheoccasionofhisNobel,
thosewhohadcometoknowhimonlyrecentlyassumed,recallsBogen,“thathe’s
gonereligiouslikesomanyoldfolks.”By1990,evenCaltechprofessorswhohad
knownSperryforfourdecades“hadgivenuptryingtodefendoreventounderstand
‘thephilosophyofhislateryears,’asoneofthemputit.”
AlthoughSperryputgreatstressontherealityofthemindinthecausalchain,
whenpressedheseemedtofallbackonclassicalmaterialistassumptions.He
emphaticallydeniedtheimportanceofquantummechanicsforunderstandingmindbrainrelations,insistingthatNewtonianphysicswasentirelyuptothetask.“It
remainstrueinthementalistmodelthattheparts…determinethepropertiesofthe
whole,i.e.microdeter-minismisnotabandoned,”hewroteinhislastmajorpaper.
“Theemergentprocessis…inprinciple,predictable.”Thusthementalforceshewas
sofondofreferringtowerethemselvesdeterminedfrombelow.Tothose,likeme,
whowerebecomingcommittedtothegenuinepowerofmentalforceandits
integralroleinaquantum-basedmind-braintheory,Sperry’sviewsseemedlikea
refinedformofepiphenomenalism.
AGNOSTICPHYSICALISMalsoholdsthatmindderivesexclusivelyfromthematterof
thebrain.Incontrasttotheepiphenomenalistsandfunctionalists,however,
adherentsofthisschoolacknowledgethatthismaynotbethewholestory.Thatis
whatthe“agnostic”partreflects:thosewhosubscribetothisworldviewdonotdeny
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theexistenceofnonmaterialforces,justasanagnosticdoesnotactivelydenythe
existenceofGod.Rather,theyregardsuchinfluences,iftheyexist,ascapableof
affectingmentalstatesonlyastheyfirstinfluenceobservablecerebralstates.
WilliamJamesfallsintothiscamp.JoeBogeniscarefultodistinguishphysicalism
frommaterialism.Theformerholdsthatthementaldoesnotchangewithoutthe
physical’s(thatis,brainstates)changing,too.Thissaysnothingabouttheexistence
ofnonmaterialinfluencesonthemind.Itsimplyassertsthatanysuchinfluences
mustworkthroughthebraininordertoaffectthemind.Incontrast,materialism
transcendsphysicalisminactivelydenyingtheexistenceofnonmaterialinfluences.
Inexplaininghisownposition,Bogenrecountsanargumentheoncehadwith
thephilosopherPaulChurchlandaboutthemysteryofhowbrainproducesmind,
andtheneedsomephilosophersandneuroscientistsperceivetoinvokesomething
immaterialandwithoutspatialextenttoaffectthebrain.Churchlandburstout,
“Throughoutthehistoryofthissubjectthemindhasbeenconsideredtobebetween
Godandbrain.ButnowyoupresumetoputthebrainbetweenGodandmind.”To
whichBogenreplied,“Exactlyso,whichishowIcanbeacommittedphysicalist
whileremainingagnosticorevenindifferentabouttheimmaterial.”
PROCESSPHILOSOPHY,aschoolgreatlyinfluencedbyAlfredNorthWhitehead,
holdsthatmindandbrainaremanifestationsofasinglereality,onethatisin
constantflux.ItthusiscompatiblewithclassicalBuddhistphilosophy,whichviews
clearandpenetratingawarenessofchangeandimpermanence(aniccainPali)asthe
essenceofinsight.Thus,asWhiteheadputit,“Therealityistheprocess,”anditisa
processmadeupofvitaltransient“dropsofexperience,complexand
interdependent.”Thisviewisstrikinglyconsistentwithrecentdevelopmentsin
quantumphysics.
DUALISTICINTERACTIONISMholdsthatconsciousnessandotheraspectsofmindcan
occurindependentlyofbrain.Inthisview,mentalstateshavethepowertoshape
brainorcerebralstates—and,goingevenfurther,themindcannotinanysensebe
reducedtothebrain.Althoughminddependsonbrainforitsexpression,brainisby
itsverymaterialnaturenotsufficienttoexplainmindcompletely,forconsciousness
andeverythingelselumpedunderthisthingcalledmindarecategoricallydifferent
beastsfrombrainandeverythingelsematerial.JohnEccles,whoalongwiththe
philosopherKarlPopperformanyyearsgallantlychampionedthisview,putitthis
waynotlongbeforehisdeath:“Theessentialfeatureofdualist-interactionismisthat
themindandbrainareindependententities…andthattheyinteractbyquantum
physics.”Scientistsandphilosophersinthiscamprejectmaterialismtothepointof
actuallypositinganonmaterialbasisforthemind.Evenworse,theyseemtohavea
penchantforspeakingaboutthepossibilityoflifeafterdeath,somethingnoselfrespectingscientistissupposedtodoinpublic(althoughbothEcclesandPenfield
did).Evenscientistsandphilosopherswhoquestionwhethersimplymappingneural
correlatescantrulyprovidetheultimateanswerhavedoubtsaboutdualistic
interactionism:neuroscientistsmayhaveworldstogobeforetheyunderstandhow
braingivesrisetomind,buteveninafieldnotgenerallymarkedbycertaintythey
areassureassurecanbethatitdoes,somehow,managethetrick.
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