KantLecture4
ReviewSyntheticaprioriknowledge
Statementsinvolvingnecessityorstrictuniversalitycouldneverbeknown
onthebasisofsenseexperience,andarethusknown(ifknownatall)a
priori.Humehasclaimedthattheonlystatementswecanknowaprioriare
statementswherethesubjectiscontainedinthepredicate,i.e.,statement
whosenegationsarecontradictory.Thisseemseminentlyplausible.
Statementswhosenegationsarenotcontradictorytellussomething
substantive.Theyarenottruemerelyinvirtueofthemeaningsofthewords.
Howcoulditbepossibleforustoknowsuchstatementswithouttheuseof
senseexperience?So,forHume,theonlystatementsinvolvingnecessityor
strictuniversality(theonlystatementswecouldknowapriori)wouldbe
statementswherethesubjectiscontainedinthepredicate,i.e.whatKant
wouldcallanalyticstatements.SoHumewoulddenythepossibilityof
syntheticaprioriknowledge.
Claimsofarithmeticandgeometryaresynthetic,notanalytic.Buttheyare
necessarilytrue,andhence,ifknownatall,mustbeknownapriori.
Thismeansthattheyarenot,inHume’sterms,mererelationsofideas.Itis
notthecase,inthesestatements,thatthepredicateiscontainedinthe
subject.Thesestatementsarenotsuchthattheirnegationsare
contradictory.So,ifwedoindeedknowthemtobetrue,thenitmustbe
possibletoknowsomesyntheticstatementsthatarenecessarilyor
universallytrue.
KantthinksthisisadevastatingblowtoHume.Hume’schallengeisgood
one.Itdoesnotseempossibletoknowinadvanceofexperienceanything
thatisnotlogicallytrue.Buttheclaimsofmathematicsandgeometryare
knownindependentlyofsenseexperience,andarenotlogicallytrue.So,
eitherwedon’tknowthematall(aclaimKantthinksHumewouldnever
haveaccepted),orelseitisindeedpossibletohavesyntheticapriori
knowledge.
Kanthasclaimed,inthePrefaceandsuggestedintheIntroduction,thatsuch
knowledgecouldbepossibleonlyifitreflectedsomething,inourexperience
ofobjectsthatwasduetothenatureofourconsciousnessofobjectsrather
thantotheintrinsicnatureoftheobjectsofourconsciousness.Thiswould
besomething,inourexperienceofobjects,thatreasoncontributedaftera
planofitsown.Initially,thisismerelyahypothesis,apossibleexplanation.
Inthenextsection,Kantbeginstomorefullyexplainhowthishypothesis
couldexplainthepossibilityofouraprioriknowledgeofthesynthetictruths
ofarithmeticandgeometry.Knowledgeofthesestatementsispossible
becausetheyreflectsomethingreasonhascontributed.Kant’sclaimisthat
timeandspacearenotfeaturesofrealityasitisinitself,butthenecessary
formsofourperceptionsofobjects.Theyareduenottotheindependent
natureofreality,buttothewayourmindswork.Knowledgeofarithmeticis
possiblebecausetimeistheformofinnersense.Knowledgeofgeometryis
possiblebecausespaceistheformofoutersense.So,forKant,timeand
spaceareempiricallyrealbuttranscendentallyideal.
SensibilityandUnderstanding
Ihavethusfarusedthemetaphoroftherose-coloredglassestoexplainwhat
Kantmeantbysayingthatthereissomething,inourexperienceofobjects,
that“reasoncontributesafteraplanofitsown.”Theideaisthatthereare
certainpartsofourexperienceofobjectsthatreflectsnottheintrinsicnature
ofthethings(inthemselves)thatappeartous,butratherthesubjective
necessityforhowanythingcanappeartousthroughconsciousness.Atthis
pointKantmakesclearthattherearetwodistinctaspectstothis
“contribution.”The“Understanding”makesa“contribution”totheconcepts
wenecessarilyuseinorderto“think”ofsomethingasanobject,andthe
“Sensibility”makesa“contribution”tohowoursensationsmustbe
organized.Thenextmajorsectionofthetext,“TheTranscendentalDoctrine
ofElements”discussesbothofthesetwocontributions.Thefirstsection,the
“TranscendentalAesthetic,”discussessensibility,our“faculty”ofbeing
affectedbyobjectsinsensations,andthefollowingsection(whichwewill
notbereading),“TheTranscendentalLogic,”discussesour“faculty”of
understanding.Thoughweareonlyreadingthefirstofthesetwosections,I
willhavealittletosayaboutbothinexplainingthedifference,andwhyKant
thinkstheremustbetwosuch“contributions”thatthemindmakestohow
thingsmustnecessarilyappeartousinconsciousexperience.
So,tocontinuewithourmetaphor,therose-coloredglasses(thatwemust
wearinordertobeconsciousofobjects)performtwodistinctfunctions:
first,the“rawdata”ofthesensesmustbeorganizedintoaspatio-temporal
array.Thisisthesubjectmatterofthesectionwearereading,the
“TranscendentalAesthetic.”Butafterthis,this“spatio-temporalized”array
ofsensedatamustbecategorized(or“synthesized”)accordingtotherules
forwhatitisforsomethingtobeexperiencedasanenduringobjectthat
persiststhroughchangesofitsproperties.
IntuitionasourFacultyofSensibility
Inordertounderstandthesetwodistinct“faculties”(orthesetwodistinct
subjectivecontributionstohowweexperienceobjects),Kantthinksthatwe
mustfirst“isolatesensibility,bytakingawayfromiteverythingwhichthe
understandingthinksthroughitsconcepts,sothatnothingremainssave
empiricalintuition.”[p.221ofourtext]Ifyouthinkofyoursenseexperience
rightnow,youhaveakindof“innerTVorcomputerscreen,”composedof
coloredshapeswhichyouunderstandorinterpretasanexperienceofa
roomfullofpeopleandotherobjects.Itisthe“understanding”thatdoesthis
interpreting.You“understand”thatitiscertaincollectionsofcolorsthat
representatable,othergroupsofshapesandcolorsthatrepresentme,etc.
Thinkingofthis“screen”asakindofcomputermonitor,youcanthinkof
thesecolorsandshapesascollectionsofpixels.Itisyourunderstandingthat
“categorizes”thesecollectionsofpixelsintoexperiencesofobjects.Whenwe
“isolate”sensibility,weconsiderthesearrangementsofpixelsassuch,
withoutthinkingabouthowwegroupthemintoexperiencesofobjects.The
rulesforhowwedothatarewhatKantdiscussesinthenextsection,which
wearen’treading.Thedataonthecomputerscreenchangesfrommoment
tomoment.Thecomputerdoesn’t“know”thatacertainarrangementof
pixelsatonemoment—inone“frame”—arerepresentationsofthesame
objectassomearrangementofpixelsatanothermoment—onthenext
“frame.”Thegeneralrulesfororganizingpixelsfromonemomenttothe
next,of“synthesizing”themorholdingthemtogethertocountthemas
representationsofthesameenduringobject,thesearethewhatKantcalls
the“CategoriesoftheUnderstanding.”Thesearerulesthatthemindusesto
“understand”theever-changingdataofsensationsasconstitutingthesame
(ordifferent)objectsofexperience.
ButwhatKantisconcernedwithinthissectionistheorganizationofthose
pixelswithinandacross“frames.”Thatis,evenafterweisolatesensibility
fromtheconceptsusedtointerpretit,wemuststilldistinguishbetween
whatKantcallsthe“matter”andthe“form”ofintuition.(Kantcallsthese
“uncategorized”or“unconceptualized”aspectsofourexperiencesofobjects
“intuitions.”)The“matter”ofintuitionaretheactualsensationsthatoccurin
usbybeingaffectedbyobjects.The“form”istheorganizationofthose
sensationsthatissuppliedbytheminditself.This“form”ofintuition,Kant
calls“pureintuition,”or“thepureform”ofourempiricalintuitionofobjects.
Inthepassagecitedabove,Kantsaysthatwemust“isolate”sensibilityfrom
thecontributionsoftheunderstanding.Togettotheformofintuition,Kant
continues,“weshallalsoseparateofffromit[i.e.,fromsensibility]everything
whichbelongstosensation,sothatnothingremainssavepureintuitionand
themereformofappearances,whichisallthatsensibilitycansupplya
priori.”[p.221]Andwhatsensibilitycan“supplyapriori”aretwoformsof
intuition,namelytime,asthepureformof“innerintuition”andspaceasthe
pureformof“outerintuition.”
TimeandSpaceasthepureformsofinnerandouterintuition
Wehavesensations(intuitions)ofourowninnerstates.Kantcallsthis
“innersense.”Inaddition,wehaveintuitionsofthingsoutsideofourminds,
thatis,ofthingsthatexistinadifferentspatiallocation.Kantcallsthis“outer
sense.”Kantclaimsthattimeistheformofinnersenseandthatspaceisthe
formofoutersense.
Letmecontinuetousethemetaphorofacomputerscreen.Youcanthinkof
thisasexplainingwhatgoeson(inthemind)inordertocreatethe“picture”
thatyouseeinyourmind’seye.
Thecomputerdoesn’tsend(analog)“pictures”tothecomputerscreen.
Likewise,youreyesdon’tsendlittlepicturestoyourbrain.Whatthe
computersendstothescreen(tothe“displaydriver”)isaseriesofzero’sand
one’s,alinear(orone-dimensional)streamofinformation.Somethinginthe
displaysoftware(thedisplaydriver)tellsthemonitorhowtodisplaythis
information.Thefirst“packet”ofbytestellsithowtolightupthetop-left
pixelonthescreen.Thenextpackettellsithowtolightupthenextpixelto
itsright,allthewayuntilthetoplineofpixelsislitup.Thenittellsitafterso
manypixelstogodownonerow,andgobacktothefarleft,andprovides
informationonhowthatpixelistobeilluminated.Andthentherestofthat
row,etc.,allthewaydowntothebottomofthescreen.Aftertheentire
screenhasbeenilluminated,ittellsittostartoveragainatthetopofthe
screen,withanewsetofinstructions.Andallofthisisrepeateddozensof
timespersecond.
Somethingsimilarmustgooninsideyourownmind.Thedatasentfromthe
senseorganstothebrainisjustalinearseriesofinformation.Something
insideofusmusttellushowto“display”thisinformation.Something“inside
us,”thatis,organizesthedataofsensibilityandorganizesitintoaspatiotemporal“manifold.”
So,Kantissaying,itissomethinginus,somethingcontributedbythenature
oftheconscioussubject,thatspatio-temporlizesthedatawereceivefrom
sensibility.Thatmeansthatspaceandtimeandnotfeaturesofrealityin
itself,butareinsteadnecessaryfeaturesofhowweorganizethedatawe
receivefromindependentobjects.Timeistheformofinnersense,andspace
istheformofoutersense.(Arithmeticformalizestherulesforhowwe
organizeinnersense,i.e.,asonemomentafteranother,afteranother,etc.
Theformoftimeis,ifyouwill,“plusonemore,plusonemore,plusonemore,
etc.”)So,syntheticaprioriknowledgeofarithmeticispossiblebecausetime
istheformofinnersense.Syntheticaprioriknowledgeofgeometryis
possiblebecausethisrepresentshowwearrangesensedataspatially.That
is,wecanhavesyntheticaprioriknowledgeofarithmeticandgeometry
becausetheyreflectsomethingthat“reasonhascontributed,”i.e.,timeand
space.Timeandspacearethus,forKant,notfeaturesofindependentlyreal
thingsinthemselves,butfeaturesofourexperiencethatarecontributedby
themind.Timeandspacearethus“transcendentallyideal.”
Buttimeandspacearethenecessarywaysinwhichweorganizethisdataof
sensibility.Thatiswhywecanknowinadvancethateverythingwewillever
perceivewillbeperceivedasexistingintimeandortimeandspace.Since
theyarenecessaryfeaturesofourhowwemustalwaysexperienceobjects,
spaceandtimeare“empiricallyreal.”Thatis,theyarenecessarypartofallof
ourexperiencesofobjects.
Timeandspace(aswellastheobjectsinthem)arethusatonceempirically
real(realwithintherealmofhowwenecessarilyexperiencethings)andyet
transcendentallyideal(notpartsofrealityinitself,butmerelyofhowwe
necessarilyexperiencethings.)
Diagrams:
Westartedinthiscoursewithwhatwemightcall“NaïveRealism.”Onthis
view,ourconsciousnessofobjectisadirectrelationbetweenthemindand
theobjectweareconsciousof.Wecouldpictureitthus:
But,wesaw,wehavetroubleexplainingthingslikehallucinationonthiskind
ofpicture.Whenwehallucinate,itseemsthatweseesomething,butit
cannotbeanindependentlyexistingobject.Whenwehallucinate,thereisno
independentobjectthereforustosee.Andsoitseemsplausibletosaythat
insuchcases,whatweseeissomethingthatexistsonlyinourmind,
somethinglikeanideaorsensation.Wemightrepresentthisviewwiththe
followingdiagram:inconsciousness,whatweareimmediatelyawareofis
notsomethingoutsideourmind,butrathersomethingthatexistsonlyinour
mind.Thus:
Inthiscase,howdoweunderstandwhathappensinperception,i.e.,when
wearenothallucinating,andtherereallyissomeexternalobjectthereforus
tosee?Wewouldthenrepresentitlikethis:
So,onthismodel,inallcaseswhatwearedirectlyandimmediatelyawareof
isalwaysmerelyanideaorsensationthatexistsinourmind.Inthecaseof
hallucination,thereisnoobjectintheexternalworldthatthisideaactually
represents.Inthecaseofperception,theideawearedirectlyawareofis
causedbyanexternalobject,andcorrectlyrepresentsthatexternalobject.
ThisistheaccountofperceptionwefindinbothDescartesandLocke.(For
whatit’sworth,itisalsofoundinmanyotherviewsthroughoutthehistoryof
philosophy,includingsometherearestillheldtoday.)
But,wesaw,bothBerkeleyandHumepointedoutproblemswiththis
account.(Theyareessentiallythesamesortsofproblemsthatwebegan
withinDescartes.)Ifallthatweeverdirectlyperceiveareideasinour
minds,howcanweeverjustifyourbeliefthatthereisanyworldthatexists
outsideourminds?Descartesthoughthecouldarguefortheexistenceof
suchaworldbymakinganappealtothefactthatGodisnotadeceiver.
Berkeleyarguedthatifallthatwecanconceiveofareideasinthemind,then
wecannotevenconceiveofaworldofmaterialsubstancesthatwerenot
ideasinthemind.(Thatisthethrustofhis“MasterArgument.”)Hume
arguedthatwehavenoevidencefortheexistenceofsuchmaterial
substance,andthat,likewise,wehavenoevidencefortheexistenceofmental
substanceeither.Inbothcases,theirreasoningstemmedfromtaking
seriouslytheclaimthatwedirectlyperceiveonlyideasinourminds.Once
weacceptthis,itseems,weareledeithertoBerkeley’sidealismorHume’s
skepticism.
Kant’stranscendentalidealism,Ithink,avoidstheseproblems.The
“representationalrealist”(whatispicturedinthediagramabovelabeled
“Locke’sCausalTheoryofPerception”)arguesthattheobjectsofexperience
aredifferentfromwhat(asNaïveRealists)weoriginallythoughttheywere:
theobjectsofdirectandimmediateexperiencearemerelyideasinour
minds,andnotobjectsthatexistindependentlyofourconsciousnessofthem.
Kant’stranscendentalidealism,ontheotherhands,arguesthatisthe
experienceofobjects(howobjectsnecessarilyappeartoconsciousness)that
isdifferentformwhat(asNaïveRealistsweoriginallythought:we
experienceobjectonlyastheyappeartous(throughtheinterpretivelensof
consciousness),andnotastheyareinthemselves.OnKant’sview,theobject
thatweexperiencearejustwhatwealwaysthoughttheywere:mind
independentthingsinthemselves.Itisjustthatwenever(notevenin
introspectionoftheideasorsensationsinsideourownminds)experience
theseobjectastheyareinthemselves,butonlyastheyappeartousthrough
oursubjectiveexperiential“faculties.”AndsoKant’stranscendental
idealismcouldberepresentedthus:
Kant’sAccountofExperience
Erkenntnis (“Cognition”)
Here,itis(inthediagram)the“arrow”thatisdifferentthanweinitiallythought,not
theobjectthatthearrowispointingat.Thisbig“bulge”inthelinerepresentswhatI
havecalledthe“rose-colored”glasses.Thisrepresentswhat“reasonsproduces
afteraplanofitsown,”i.e.,theconditionsofthepossibilityofconsciousnessof
objectsthatareduetothenatureofconsciousnessitself,andnottothenatureof
realityinitself.
Inclasstoday,wetalkedmoreaboutthesetwoaspectsofwhatliesaprioriinthe
mind,thatis,abouttherolesofthe“understanding”andof“intuition.”Iwon’ttryto
conveyallofthathere.Buthopefullythesediagrams,andthediscussionabove,
helpstounderstandKant’sTranscendentalIdealism.