The’primaryqualities’donotcorrespondinthiswaytoanobjectiveworldradicallyopposedtothesubjective。Spaceisnotaformofthings，butaformimposeduponthedataofexperiencebytheminditself。This，asKantsays，supposesarevolutioninphilosophycomparabletotherevolutionmadebyCopernicusinastronomy。Wehavecompletelytoinvertourwholesystemofconceivingtheworld。WhateverthevalueofKant’sdoctrine，ofwhichIneedheresaynothing，itwasundoubtedlymoreprolificthanReid’s。Reid’swasfarlessthoroughgoing。Hedoesnotdrawanewlinebetweenobjectandsubject，butsimplyendeavourstoshowthatthedilemmawasduetocertainassumptionsaboutthenatureof’ideas。’Therealhadbeenaltogetherseparatedfromthephenomenal，ortruthdivorcedfromfact。Youcanonlyhavedemonstrationsbygettingintoaregionbeyondthesensibleworld；whilewithinthatworld——thatis，theregionofordinaryknowledgeandconduct——youaredoomedtohopelessuncertainty。Anescape，therefore，mustbesoughtbysomethoroughrevisionoftheassumedrelation，butnotbyfallingbackupontheexplodedphilosophyoftheschools。ReidandhissuccessorswerequiteasmuchaliveasLocketothedangeroffallingintomerescholasticlogomachy。They，too，willinsomesensebaseallknowledgeuponexperience。ReidconstantlyappealstotheauthorityofBacon，whomheregardsasthetruefounderofinductivescience。ThegreatsuccessofBacon’smethodinthephysicalsciences，encouragedthehope，alreadyexpressedbyNewton，thatasimilarresultmightbeachievedin’moralphilosophy。’21*Humehaddonesomethingtocleartheway，butReidwas，asStewartthinks，thefirsttoperceiveclearlyandjustlythe’analogybetweenthesetwodifferentbranchesofhumanknowledge。’Themindandmatteraretwoco-ordinatethings，whosepropertiesaretobeinvestigatedbysimilarmethods。Philosophythusmeansessentiallypsychology。Thetwoinquiriesaretwo’branches’ofinductivescience，andtheproblemistodiscoverbyaperfectlyimpartialexaminationwhatarethe’fundamentallawsofmind’revealedbyanaccurateanalysisofthevariousprocessesofthought。
　　ThemainresultofReid’sinvestigationsisgivenmostpointedlyinhisearlyInquiry，andwasfullyacceptedbyStewart。Brieflyitcomestothis。Noonecandoubtthatwebelieve，asafact，inanexternalworld。Webelievethattherearesunandmoon，stones，sticks，andhumanbodies。Thisbeliefisacceptedbythescepticaswellasbythedogmatist，althoughthescepticreducesittoamereblindcustomor’associationofideas。’NowReidarguesthatthebelief，whateveritsnature，isnotandcannotbederivedfromthesensations。Wedonotconstructthevisibleandtangibleworld，forexample，simplyoutofimpressionsmadeuponthesensesofsightandtouch。Toprovethis，heexamineswhataretheactualdataprovidedbythesesenses，andshows，ortriestoshow，thatwecannotfromthemaloneconstructtheworldofspaceandgeometry。Hence，ifweconsiderexperienceimpartiallyandwithoutpreconception，wefindthatittellsussomethingwhichisnotgivenbythesenses。Thesensesarenotthematerialofourperceptions，butsimplygivetheoccasionsuponwhichourbeliefiscalledintoactivity。Thesensationisnomoreliketherealityinwhichwebelievethanthepainofawoundisliketheedgeoftheknife。Perceptiontellsusdirectlyandimmediately，withouttheinterventionofideas，thatthereis，asweallbelieve，arealexternalworld。
　　Reidwasavigorousreasoner，andcredithasbeengiventohimbysomedisciplesofKant’sdoctrineoftimeandspace。Schopenhauer22*saysthatReid’s’excellentwork’givesacomplete’negativeproofoftheKantiantruths’；
　　thatistosay，thatReidprovessatisfactorilythatwecannotconstructtheworldoutofthesense-givendataalone。But，whereasKantregardsthesensesassupplyingthematerialsmouldedbytheperceivingmind，Reidregardsthemasmerestimuliexcitingcertaininevitablebeliefs。AsaresultofReid’smethod，then，wehave’intuitions。’Reid’sessentialcontentionisthatafairexaminationofexperiencewillrevealcertainfundamentalbeliefs，whichcannotbeexplainedasmeremanifestationsofthesensations，andwhich，bytheveryfactthattheyareinexplicable，mustbeacceptedasan’inspiration。’23*
　　Reidprofessestodiscoverthesebeliefsbyaccuratelydescribingfacts。
　　Hefindsthemthereasachemistfindsanelement。The’intuition’ismadebysubstitutingfor’ideas’amysteriousandinexplicableconnectionbetweenthemindandmatter。24*Thechasmexistsstill，butitissomehowbridgedbyaquasi-miracle。Admitting，therefore，thatReidshowsagaptoexistinthetheory，hisresultremains’negative。’Thephilosopherwillsaythatitisnotenoughtoassertaprincipledogmaticallywithoutshowingitsplaceinareasonedsystemofthought。Thepsychologist，Ontheotherhand，whotakesReid’sownground，mayregardthestatementonlyasausefulchallengetofurtherinquiry。Theanalysishithertogivenmaybeinsufficient，butwhereReidhasfailed，otherinquirersmaybemoresuccessful。Assoon，infact，asweapplythepsychologicalmethod，andregardthe’philosophyofmind’asan’inductivescience，’itisperilous，ifnotabsolutelyinconsistent，todiscover’intuitions’whichwilltakeusbeyondexperience。Thelineofdefenceagainstempiricismcanonlybeprovisionalandtemporary。Inhismainresults，indeed，Reidhadtheadvantageofbeingonthesideof’commonsense。’Everybodywasalreadyconvincedthatthereweresticksandstones，andeverybodyispreparedtohearthattheirbeliefisapprovedbyphilosophy。
　　Butadifficultyariseswhenasimilarmethodisappliedtoadoctrinesincerelydisputed。Tothestatement，’thisisanecessarybelief，’itisasufficientanswertoreply，’Idon’tbelieveit。’Inthatcase，anintuitionmerelyamountstoadogmaticassumptionthatIaminfallible，andmustbesupportedbyshowingitsconnectionwithbeliefsreallyuniversalandadmittedlynecessary。
　　DugaldStewartfollowedReiduponthismainquestion，andwithlessforceandoriginalityrepresentsthesamepointofview。HeacceptsReid’sviewofthetwoco-ordinatedepartmentsofknowledge；thescienceofwhichmind，andthescienceofwhichbody，istheobject。Philosophyisnota’theoryofknowledge’oroftheuniverse；but，asitwasthencalled，’aphilosophyofthehumanmind。’’Philosophy’isfoundeduponinductivepsychology；anditonlybecomesphilosophyinawidersenseinsofaraswediscoverthatasafactwehavecertainfundamentalbeliefs，whicharethusgivenbyexperience，thoughtheytakeusinasensebeyondexperience。Jeffrey，reviewingStewart’slifeofReid，intheEdinburghReviewof1804，makesasignificantinferencefromthis。Bacon’smethod，hesaid，hadsucceededinthephysicalsciences，becausetherewecouldapplyexperiment。Butexperimentisimpossibleinthescienceofmind；andthereforephilosophywillneverbeanythingbutaplaythingorausefulvarietyofgymnastic。StewartrepliedatsomelengthinhisEssays，25*fullyacceptingthegeneralconception，butarguingthattheexperimentalmethodwasapplicabletothescienceofmind。Jeffreyobservesthatitwasnowadmittedthatthe’profoundestreasonings’hadbroughtusbacktotheviewofthevulgar，andthis，too，isadmittedbyStewartsofarasthecardinaldoctrineof’thecommonsense’philosophy，thetheoryofperception，isadmitted。
　　Fromthis，again，itfollowsthatthe’notionsweannextothewordsMatterandMindaremerelyrelative。’26*Weknowthatmindexistsasweknowthatmatterexists；or，ifanything，weknowtheexistenceofmindmorecertainlybecausemoredirectly。Themindissuggestedby’thesubjectsofourconsciousness’；
　　thebodybytheobjects’ofourperception。’But，ontheotherhand，wearetotally’ignorantoftheessenceofeither。’27*Wecandiscoverthelawseitherofmentalormoralphenomena；butalaw，asheexplains，meansinstrictnessnothingbuta’generalfact。’28*Itisidle，therefore，toexplainthenatureoftheunionbetweenthetwounknowablesubstances；wecanonlydiscoverthattheyareunitedandobservethelawsaccordingtowhichonesetofphenomenacorrespondstotheother。Fromamisunderstandingofthisariseallthefallaciesofscholasticontology，’themostidleandabsurdspeculationthateveremployedthehumanfaculties。’29*Thedestructionofthatpseudo-sciencewasthegreatgloryofBaconandLocke；andReidhasnowdiscoveredthemethodbywhichwemayadvancetotheestablishmentofatrulyinductive’philosophyofmind。’
　　ItisnotsurprisingthatStewartapproximatesinvariousdirectionstothedoctrinesoftheempiricalschool。Heleanstowardsthemwheneverhedoesnotseetheresultstowhichheistending。Thus，forexample，heisathorough-goingnominalist；30*andonthispointhedesertstheteachingofReid。HedefendsagainstReidtheattackmadebyBerkeleyandHumeupon’abstractideas。’Rosmini，31*inanelaboratecriticism，complainsthatStewartdidnotperceivetheinevitabletendencyofnominalismtomaterialism。32*
　　Stewart，infact，acceptsagooddealofHorneTooke’sdoctrine，33*thoughcallingTookean’ingeniousgrammarian，notaveryprofoundphilosopher，’
　　butholds，asweshallsee，thatthematerialistictendencycanbeavoided。
　　Asbecomesanominalist，heattacksthesyllogismupongroundsmorefullybroughtoutbyJ。S。Mill。Uponanotheressentialpoint，heagreeswiththepureempiricists。HeacceptsHume’sviewofcausationinallquestionsofphysicalscience。Innaturalphilosophy，hedeclarescausationmeansonlyconjunction。Thesensescannevergiveusthe’efficient’causeofanyphenomenon。
　　Inotherwords，wecanneverseea’necessaryconnection’betweenanytwoevents。HecollectspassagesfromearlierwriterstoshowhowHumehadbeenanticipated；andholdsthatBacon’sinadequateviewofthistruthwasamaindefectinhistheories。34*Hencewehaveacharacteristicconclusion。Hesays，whendiscussingtheproofsoftheexistenceofGod，35*thatwehavean’irresistibleconvictionofthenecessityofacause’foreverychange。
　　Hume，however，hasshownthatthiscanneverbealogicalnecessity。Itmustthen，arguesStewart，beeithera’prejudice’oran’intuitivejudgment。’
　　Sinceitisshownby’universalconsent’nottobeaprejudice，itmustbeanintuitivejudgment。ThusHume’sfactsareaccepted；buthisinferencedenied。Theactualcausalnexusisinscrutable。TheconvictionthattheremustbeaconnectionbetweeneventsattributedbyHumeto’custom’isattributedbyStewarttointuitivebelief。StewartinfersthatHume’sdoctrineisreallyfavourabletotheology。ItimpliesthatGodgivesustheconviction，andperhaps，asMalebrancheheld，thatGodis’theconstantlyoperatingefficientCauseinthematerialworld。’36*Stewart’ssuccessor，ThomasBrown，tookupthisargumentonoccasionoftheoncefamous’Lesliecontroversy’；andBrown’steachingwasendorsedbyJamesMillandbyJohnStuartMill。
　　AccordingtoJ。S。Mill，JamesMillandStewartrepresentedoppositepolesofphilosophicthought。Ishallhavetoconsiderthisdictumhereafter。OnthepointsalreadynoticedStewartmustberegardedasanallyratherthananopponentoftheLockeandHumetradition。Likethemheappealsunhesitatinglytoexperience，andcannotfindwordsstrongenoughtoexpresshiscontemptfor’ontological’andscholasticmethods。His’intuitions’aresofarveryharmlessthings，whichfallinwithcommonsense，andenablehimtoholdwithoutfurthertroublethebeliefswhich，asamatteroffact，areheldbyeverybody。Theyareanexcusefornotseekinganyultimateexplanationinreason。Heis，indeed，opposedtotheschoolwhichclaimedtobethelegitimatesuccessortoLocke，butwhichevadedHume’sscepticismbydivergingtowardsmaterialism。ThegreatrepresentativeofthisdoctrineinEnglandhadbeenHartley，andinStewart’sdayHartley’sleadhadbeenfollowedbyPriestley，whoattackedReidfromamaterialistpointofview，byPriestley’ssuccessor，ThomasBelsham，andbyErasmusDarwin。WefindStewart，inlanguagewhichremindsusoflatercontroversy，denouncingthe’DarwinianSchool’37*fortheoriesaboutinstinctincompatiblewiththedoctrineoffinalcauses。Itmightappearthataphilosopherwhohasre-establishedtheobjectiveexistenceofspaceinoppositiontoBerkeley，wasindangerofthatmaterialismwhichhadbeenBerkeley’sbugbear。ButStewartescapesthedangerbyhisassertionthatourknowledgeofmatteris’relative’orconfinedtophenomena。Materialismisforhimavarietyofontology，involvingtheassumptionthatweknowtheessenceofmatter。TospeakwithHartleyof’vibrations，’animalspirits，andsoforth，istobeledastraybyafalseanalogy。Wecandiscoverthelawsofcorrespondenceofmindandbody，butnottheultimatenatureofeither。38*