OfScepticismwithregardtoReason。
Inalldemonstrativesciencestherulesarecertainandinfallible；butwhenweapplythem，ourfalliblesaiduncertainfacultiesareveryapttodepartfromthem，andfallintoerror。Wemust，therefore，ineveryreasoningformanewjudgment，asacheckorcontroulonourfirstjudgmentorbelief；andmustenlargeourviewtocomprehendakindofhistoryofalltheinstances，whereinourunderstandinghasdeceiv’dus，compar’dwiththose，whereinitstestimonywasjustandtrue。Ourreasonmustbeconsideredasakindofcause，ofwhichtruthisthenaturaleffect；butsuch-a-oneasbytheirruptionofothercauses，andbytheinconstancyofourmentalpowers，mayfrequentlybeprevented。Bythismeansallknowledgedegeneratesintoprobability；andthisprobabilityisgreaterorless，accordingtoourexperienceoftheveracityordeceitfulnessofourunderstanding，andaccordingtothesimplicityorintricacyofthequestion。
ThereisnoAlgebraistnorMathematiciansoexpertinhisscience，astoplaceentireconfidenceinanytruthimmediatelyuponhisdiscoveryofit，orregarditasanything，butawereprobability。Everytimeherunsoverhisproofs，hisconfidenceencreases；butstillmorebytheapprobationofhisfriends；andisrais’dtoitsutmostperfectionbytheuniversalassentandapplausesofthe，learnedworld。Now’tisevident，thatthisgradualencreaseofassuranceisnothingbuttheadditionofnewprobabilities，andisderiv’dfromtheconstantunionofcausesandeffects，accordingtopastexperienceandobservation。
Inaccomptsofanylengthorimportance，Merchantsseldomtrusttothe，infalliblecertaintyofnumbersfortheirsecurity；butbytheartificialstructureoftheaccompts，produceaprobabilitybeyondwhatisderiv’dfromtheskillandexperienceoftheaccomptant。Forthatisplainlyofitselfsomedegreeofprobability；tho’uncertainandvariable，accordingtothedegreesofhisexperienceandlengthoftheaccompt。Nowasnonewillmaintain，thatourassuranceinalongnumerationexceedsprobability，Imaysafelyaffirm，thattherescarceisanypropositionconcerningnumbers，ofwhichwecanhaveafullersecurity。For’tiseasilypossible，bygraduallydiminishingthenumbers，toreducethelongestseriesofadditiontothemostsimplequestion，whichcanbeform’d，toanadditionoftwosinglenumbers；anduponthissuppositionweshallfinditimpracticabletoshewthepreciselimitsofknowledgeandofprobability，ordiscoverthatparticularnumber，atwhichtheoneendsandtheotherbegins。Butknowledgeandprobabilityareofsuchcontraryanddisagreeingnatures，thattheycannotwellruninsensiblyintoeachother，andthatbecausetheywillnotdivide，butmustbeeitherentirelypresent，orentirelyabsent。Besides，ifanysingleadditionwerecertain，everyonewou’dbeso，andconsequentlythewholeortotalsum；unlessthewholecanbedifferentfromallitsparts。Ihadalmostsaid，thatthiswascertain；butIreflectthatitmustreduceitself，aswellaseveryotherreasoning，andfromknowledgedegenerateintoprobability。
Sincethereforeallknowledgeresolvesitselfintoprobability，andbecomesatlastofthesamenaturewiththatevidence，whichweemployincommonlife，wemustnowexaminethislatterspeciesofreasoning，andseeonwhatfoundationitstands。
Ineveryjudgment，whichwecanformconcerningprobability，aswellasconcerningknowledge，weoughtalwaystocorrectthefirstjudgment，deriv’dfromthenatureoftheobject，byanotherjudgment，deriv’dfromthenatureoftheunderstanding。’Tiscertainamanofsolidsenseandlongexperienceoughttohave，andusuallyhas，agreaterassuranceinhisopinions，thanonethatisfoolishandignorant，andthatoursentimentshavedifferentdegreesofauthority，evenwithourselves，inproportiontothedegreesofourreasonandexperience。Inthemanofthebestsenseandlongestexperience，thisauthorityisneverentire；sinceevensuch-a-onemustbeconsciousofmanyerrorsinthepast，andmuststilldreadthelikeforthefuture。Herethenarisesanewspeciesofprobabilitytocorrectandregulatethefirst，andfixitsjuststandardandproportion。Asdemonstrationissubjecttothecontroulofprobability，soisprobabilityliabletoanewcorrectionbyareflexactofthemind，whereinthenatureofourunderstanding，andourreasoningfromthefirstprobabilitybecomeourobjects。
Havingthusfoundineveryprobability，besidetheoriginaluncertaintyinherentinthesubject，anewuncertaintyderiv’dfromtheweaknessofthatfaculty，whichjudges，andhavingadjustedthesetwotogether，weareoblig’dbyourreasontoaddanewdoubtderiv’dfromthepossibilityoferrorintheestimationwemakeofthetruthandfidelityofourfaculties。Thisisadoubt，whichimmediatelyoccurstous，andofwhich，ifwewou’dcloselypursueourreason，wecannotavoidgivingadecision。Butthisdecision，tho’itshou’dbefavourabletoourprecedingjudgment，beingfoundedonlyonprobability，mustweakenstillfurtherourfirstevidence，andmustitselfbeweaken’dbyafourthdoubtofthesamekind，andsoonininfinitum:tillatlastthereremainnothingoftheoriginalprobability，howevergreatwemaysupposeittohavebeen，andhoweversmallthediminutionbyeverynewuncertainty。Nofiniteobjectcansubsistunderadecreaserepeatedininfinitum；andeventhevastestquantity，whichcanenterintohumanimagination，mustinthismannerbereduc’dtonothing。Letourfirstbeliefbeneversostrong，itmustinfalliblyperishbypassingthro’somanynewexaminations，ofwhicheachdiminishessomewhatofitsforceandvigour。WhenIreflectonthenaturalfallibilityofmyjudgment，Ihavelessconfidenceinmyopinions，thanwhenIonlyconsidertheobjectsconcerningwhichIreason；andwhenIproceedstillfarther，toturnthescrutinyagainsteverysuccessiveestimationImakeofmyfaculties，alltherulesoflogicrequireacontinualdiminution，andatlastatotalextinctionofbeliefandevidence。
Shou’ditherebeask’dme，whetherIsincerelyassenttothisargument，whichIseemtotakesuchpainstoinculcate，andwhetherIbereallyoneofthosesceptics，whoholdthatallisuncertain，andthatourjudgmentisnotinanythingpossestofanymeasuresoftruthandfalshood；Ishou’dreply，thatthisquestionisentirelysuperfluous，andthatneitherI，noranyotherpersonwaseversincerelyandconstantlyofthatopinion。Nature，byanabsoluteanduncontroulablenecessityhasdetermin’dustojudgeaswellastobreatheandfeel；norcanweanymoreforbearviewingcertainobjectsinastrongerandfullerlight，uponaccountoftheircustomaryconnexionwithapresentimpression，thanwecanhinderourselvesfromthinkingaslong，asweareawake，orseeingthesurroundingbodies，whenweturnoureyestowardstheminbroadsunshine。Whoeverhastakenthepainstorefutethecavilsofthistotalscepticism，hasreallydisputedwithoutanantagonist，andendeavour’dbyargumentstoestablishafaculty，whichnaturehasantecedentlyimplantedinthemind，andrender’dunavoidable。
Myintentionthenindisplayingsocarefullytheargumentsofthatfantasticsect，isonlytomakethereadersensibleofthetruthofmyhypothesis，thatallourreasoningsconcerningcausesandeffectsarederiv’dfromnothingbutcustom；andthatbeliefismoreproperlyanactofthe，sensitive，thanofthecogitativepartofournatures。Ihavehereprov’d，thattheverysameprinciples，whichmakeusformadecisionuponanysubject，andcorrectthatdecisionbytheconsiderationofourgeniusandcapacity，andofthesituationofourmind，whenweexamin’dthatsubject；Isay，Ihaveprov’d，thatthesesameprinciples，whencarry’dfarther，andapply’dtoeverynewreflexjudgment，must，bycontinuallydiminishingtheoriginalevidence，atlastreduceittonothing，andutterlysubvertallbeliefandopinion。Ifbelief，therefore，wereasimpleactofthethought，withoutanypeculiarmannerofconception，ortheadditionofaforceandvivacity，itmustinfalliblydestroyitself，andineverycaseterminateinatotalsuspenseofjudgment。Butasexperiencewillsufficientlyconvinceanyone，whothinksitworthwhiletotry，thattho’hecanfindnoerrorintheforegoingarguments，yethestillcontinuestobelieve，andthink，andreasonasusual，hemaysafelyconclude，thathisreasoningandbeliefissomesensationorpeculiarmannerofconception，which’tisimpossibleformereideasandreflectionstodestroy。
Buthere，perhaps，itmaybedemanded，howithappens，evenuponmyhypothesis，thattheseargumentsabove-explain’dproducenotatotalsuspenseofjudgment，andafterwhatmannerthemindeverretainsadegreeofassuranceinanysubject？Forasthesenewprobabilities，whichbytheirrepetitionperpetuallydiminishtheoriginalevidence，arefoundedontheverysameprinciples，whetherofthoughtorsensation，astheprimaryjudgment，itmayseemunavoidable，thatineithercasetheymustequallysubvertit，andbytheopposition，eitherofcontrarythoughtsorsensations，reducethemindtoatotaluncertainty。Isuppose，thereissomequestionpropos’dtome，andthatafterrevolvingovertheimpressionsofmymemoryandsenses，andcarryingmythoughtsfromthemtosuchobjects，asarecommonlyconjoin’dwiththem，Ifeelastrongerandmoreforcibleconceptionontheoneside，thanontheother。Thisstrongconceptionformsmyfirstdecision。Isuppose，thatafterwardsIexaminemyjudgmentitself，andobservingfromexperience，that’tissometimesjustandsometimeserroneous，Iconsideritasregulatedbycontraryprinciplesorcauses，ofwhichsomeleadtotruth，andsometoerror；andinballancingthesecontrarycauses，Idiminishbyanewprobabilitytheassuranceofmyfirstdecision。Thisnewprobabilityisliabletothesamediminutionastheforegoing，andsoon，ininfinitum。’Tisthereforedemanded，howithappens，thatevenafterallweretainadegreeofbelief，whichissufficientforourpurpose，eitherinphilosophyorcommonlife。
Ianswer，thatafterthefirstandseconddecision；astheactionofthemindbecomesforc’dandunnatural，andtheideasfaintandobscure；tho’theprinciplesofjudgment，andtheballancingofoppositecausesbethesameasattheverybeginning；yettheirinfluenceontheimagination，andthevigourtheyaddto，ordiminishfromthethought，isbynomeansequal。Wherethemindreachesnotitsobjectswitheasinessandfacility，thesameprincipleshavenotthesameeffectasinamorenaturalconceptionoftheideas；nordoestheimaginationfeelasensation，whichholdsanyproportionwiththatwhicharisesfromitscommonjudgmentsandopinions。Theattentionisonthestretch:Thepostureofthemindisuneasy；andthespiritsbeingdivertedfromtheirnaturalcourse，arenotgovern’dintheirmovementsbythesamelaws，atleastnottothesamedegree，aswhentheyflowintheirusualchannel。
Ifwedesiresimilarinstances，’twillnotbeverydifficulttofindthem。Thepresentsubjectofmetaphysicswillsupplyusabundantly。Thesameargument，whichwou’dhavebeenesteem’dconvincinginareasoningconcerninghistoryorpolitics，haslittleornoinfluenceintheseabstrusersubjects，eventho’itbeperfectlycomprehended；andthatbecausethereisrequir’dastudyandaneffortofthought，inordertoitsbeingcomprehended:Andthiseffortofthoughtdisturbstheoperationofoursentiments，onwhichthebeliefdepends。Thecaseisthesameinothersubjects。Thestrainingoftheimaginationalwayshinderstheregularflowingofthepassionsandsentiments。Atragicpoet，thatwou’drepresenthisheroesasveryingeniousandwittyintheirmisfortunes，wou’dnevertouchthepassions。Astheemotionsofthesoulpreventanysubtilereasoningandreflection，sotheselatteractionsofthemindareequallyprejudicialtotheformer。Themind，aswellasthebody，seemstobeendow’dwithacertainprecisedegreeofforceandactivity，whichitneveremploysinoneaction，butattheexpenseofalltherest。Thisismoreevidentlytrue，wheretheactionsareofquitedifferentnatures；sinceinthatcasetheforceofthemindisnotonlydiverted，buteventhedispositionchang’d，soastorenderusincapableofasuddentransitionfromoneactiontotheother，andstillmoreofperformingbothatonce。Nowonder，then，theconviction，whicharisesfromasubtilereasoning，diminishesinproportiontotheefforts，whichtheimaginationmakestoenterintothereasoning，andtoconceiveitinallitsparts。Belief，beingalivelyconception，canneverbeentire，whereitisnotfoundedonsomethingnaturalandeasy。
ThisItaketobethetruestateofthequestion，andcannotapproveofthatexpeditiousway，whichsometakewiththesceptics，torejectatoncealltheirargumentswithoutenquiryorexamination。Ifthescepticalreasoningsbestrong，saythey，’tisaproof，thatreasonmayhavesomeforceandauthority:ifweak，theycanneverbesufficienttoinvalidatealltheconclusionsofourunderstanding。Thisargumentisnotjust；becausethescepticalreasonings，wereitpossibleforthemtoexist，andweretheynotdestroy’dbytheirsubtility，wou’dbesuccessivelybothstrongandweak，accordingtothesuccessivedispositionsofthemind。Reasonfirstappearsinpossessionofthethrone，prescribinglaws，andimposingmaxims，withanabsoluteswayandauthority。Herenemy，therefore，isoblig’dtotakeshelterunderherprotection，andbymakinguseofrationalargumentstoprovethefallaciousnessandimbecilityofreason，produces，inamanner，apatentunderherbandandseal。Thispatenthasatfirstanauthority，proportionedtothepresentandimmediateauthorityofreason，fromwhichitisderiv’d。Butasitissuppos’dtobecontradictorytoreason，itgraduallydiminishestheforceofthatgoverningpoweranditsownatthesametime；tillatlasttheybothvanishawayintonothing，byaregulaxandjustdiminution。Thescepticalanddogmaticalreasonsareofthesamekind，tho’contraryintheiroperationandtendency；sothatwherethelatterisstrong，ithasanenemyofequalforceintheformertoencounter；andastheirforceswereatfirstequal，theystillcontinueso，aslongaseitherofthemsubsists；nordoesoneofthemloseanyforceinthecontest，withouttakingasmuchfromitsantagonist。’Tishappy，therefore，thatnaturebreakstheforceofallscepticalargumentsintime，andkeepsthemfromhavinganyconsiderableinfluenceontheunderstanding。Werewetotrustentirelytotheirself-destruction，thatcannevertakeplace，’tilltheyhavefirstsubvertedallconviction，andhavetotallydestroy’dhumanreason。
OfScepticismwithregardtotheSenses。
Thusthescepticstillcontinuestoreasonandbelieve，eventho’beasserts，thathecannotdefendhisreasonbyreason；andbythesamerulehemustassenttotheprincipleconcerningtheexistenceofbody，tho’hecannotpretendbyanyargumentsofphilosophytomaintainitsveracity。Naturehasnotleftthistohischoice，andhasdoubtless，esteem’ditanaffairoftoogreatimportancetobetrustedtoouruncertainreasoningsandspeculations。Wemaywellask，Whatcausesinduceustobelieveintheexistenceofbody？but’tisinvaintoask，Whethertherebebodyornot？Thatisapoint，whichwemusttakeforgrantedinallourreasonings。
Thesubject，then，ofourpresentenquiryisconcerningthecauseswhichinduceustobelieveintheexistenceofbody:AndmyreasoningsonthisheadIshallbeginwithadistinction，whichatfirstsightmayseemsuperfluous，butwhichwillcontributeverymuchtotheperfectunderstandingofwhatfollows。Weoughttoexamineapartthosetwoquestions，whicharecommonlyconfoundedtogether，viz。Whyweattributeacontinu’dexistencetoobjects，evenwhentheyarenotpresenttothesenses；andwhywesupposethemtohaveanexistenceDISTINCTfromthemindandperception。UnderthislastheadIcomprehendtheirsituationaswellasrelations，theirexternalpositionaswellastheindependenceoftheirexistenceandoperation。Thesetwoquestionsconcerningthecontinu’danddistinctexistenceofbodyareintimatelyconnectedtogether。Foriftheobjectsofoursensescontinuetoexist，evenwhentheyarenotperceiv’d，theirexistenceisofcourseindependentofanddistinctfromtheperception:andviceversa，iftheirexistencebeindependentoftheperceptionanddistinctfromit，theymustcontinuetoexist，eventho’theybenotperceiv’d。Buttho’thedecisionoftheonequestiondecidestheother；yetthatwemaythemoreeasilydiscovertheprinciplesofhumannature，fromwhencethedecisionarises，weshallcarryalongwithusthisdistinction，andshallconsider，whetheritbethesenses，reason，ortheimagination，thatproducestheopinionofacontinu’dorofadistinctexistence。Thesearetheonlyquestions，thatareintelligibleonthepresentsubject。Forastothenotionofexternalexistence，whentakenforsomethingspeciallydifferentfromourperceptions，(32)wehavealreadyshewnitsabsurdity。
TobeginwiththeSENSES，’tisevidentthesefacultiesareincapableofgivingrisetothenotionofthecontinu’dexistenceoftheirobjects，aftertheynolongerappeartothesenses。Forthatisacontradictioninterms，andsupposethatthesensescontinuetooperate，evenaftertheyhaveceas’dallmannerofoperation。Thesefaculties，therefore，iftheyhaveanyinfluenceinthepresentcase，mustproducetheopinionofadistinct，notofacontinu’dexistence；andinordertothat，mustpresenttheirimpressionseitherasimagesandrepresentations，orastheseverydistinctandexternalexistences。
Thatoursensesoffernottheirimpressionsastheimagesofsomethingdistinct，orindependent，andexternal，isevident；becausetheyconveytousnothingbutasingleperception，andnevergiveustheleastintimationofanythingbeyond。Asingleperceptioncanneverproducetheideaofadoubleexistence，butbysomeinferenceeitherofthereasonorimagination。Whenthemindlooksfartherthanwhatimmediatelyappearstoit，itsconclusionscanneverbeputtotheaccountofthesenses；anditcertainlylooksfarther，whenfromasingleperceptionitinfersadoubleexistence，andsupposestherelationsofresemblanceandcausationbetwixtthem。
Ifoursenses，therefore，suggestanyideaofdistinctexistences，theymustconveytheimpressionsasthoseveryexistences，byakindoffallacyandillusion。Uponthisbeadwemayobserve，thatallsensationsarefeltbythemind，suchastheyreallyare，andthatwhenwedoubt，whethertheypresentthemselvesasdistinctobjects，orasmereimpressions，thedifficultyisnotconcerningtheirnature，butconcerningtheirrelationsandsituation。’Nowifthesensespresentedourimpressionsasexternalto，andindependentofourselves，boththeobjectsandourselvesmustbeobvioustooursenses，otherwisetheycou’dnotbecompar’dbythesefaculties。Thedifficulty，then，ishowfaxweareourselvestheobjectsofoursenses。
’Tiscertainthereisnoquestioninphilosophymoreabstrusethanthatconcerningidentity，andthenatureoftheunitingprinciple，whichconstitutesaperson。Sofarfrombeingablebyoursensesmerelytodeterminethisquestion，wemusthaverecoursetothemostprofoundmetaphysicstogiveasatisfactoryanswertoit；andincommonlife’tisevidenttheseideasofselfandpersonareneververyfix’dnordeterminate。’Tisabsurd，therefore，toimaginethesensescaneverdistinguishbetwixtourselvesandexternalobjects。
Addtothis，thateveryimpression，externalandinternal，passions，affections，sensations，painsandpleasures，areoriginallyonthesamefooting；andthatwhateverotherdifferenceswemayobserveamongthem，theyappear，allofthem，intheirtruecolours，asimpressionsorperceptions。Andindeed，ifweconsiderthematteraright，’tisscarcepossibleitshou’dbeotherwise，norisitconceivablethatoursensesshou’dbemorecapableofdeceivingusinthesituationandrelations，thaninthenatureofourimpressions。Forsinceallactionsandsensationsofthemindareknowntousbyconsciousness，theymustnecessarilyappearineveryparticularwhattheyare，andbewhattheyappear。Everythingthatentersthemind，beinginrealityaperception，’tisimpossibleanythingshou’dtofeelingappeardifferent。Thisweretosuppose，thatevenwherewearemostintimatelyconscious，wemightbemistaken。
Butnottolosetimeinexamining，whether’tispossibleforoursensestodeceiveus，andrepresentourperceptionsasdistinctfromourselves，thatisasexternaltoandindependentofus；letusconsiderwhethertheyreallydoso，andwhetherthiserrorproceedsfromanimmediatesensation，orfromsomeothercauses。
Tobeginwiththequestionconcerningexternalexistence，itmayperhapsbesaid，thatsettingasidethemetaphysicalquestionoftheidentityofathinking-substance，ourownbodyevidentlybelongstous；andasseveralimpressionsappearexteriortothebody，wesupposethemalsoexteriortoourselves。Thepaper，onwhichIwriteatpresent，isbeyondmyhand。Thetableisbeyondthepaper。Thewallsofthechamberbeyondthetable。Andincastingmyeyetowardsthewindow，Iperceiveagreatextentoffieldsandbuildingsbeyondmychamber。Fromallthisitmaybeinfer’d，thatnootherfacultyisrequir’d，besidethesenses，toconvinceusoftheexternalexistenceofbody。Buttopreventthisinference，weneedonlyweighthethreefollowingconsiderations。First，That，properlyspeaking，’tisnotourbodyweperceive，whenweregardourlimbsandmembers，butcertainimpressions，whichenterbythesenses；sothattheascribingarealandcorporealexistencetotheseimpressions，ortotheirobjects，isanactofthemindasdifficulttoexplain，asthatwhichweexamineatpresent。Secondly，Sounds，andtastes，andsmelts，tho’commonlyregardedbythemindascontinu’dindependentqualities，appearnottohaveanyexistenceinextension，andconsequentlycannotappeartothesensesassituatedexternallytothebody。’Thereason，whyweascribea，placetothem，shallbe:consideredafterwards。Thirdly，Evenoursightinformsusnotofdistanceoroutness(sotospeak)immediatelyandwithoutacertainreasoningandexperience，asisacknowledgedbythemostrationalphilosophers。
Astotheindependencyofourperceptionsonourselves，thiscanneverbeanobjectofthesenses；butanyopinionweformconcerningit，mustbederiv’dfromexperienceandobservation:Andweshallseeafterwards，thatourconclusionsfromexperiencearefarfrombeingfavourabletothedoctrineoftheindependencyofourperceptions。Meanwhilewemayobservethatwhenwetalkofrealdistinctexistences，wehavecommonlymoreinoureyetheirindependencythanexternalsituationinplace，andthinkanobjecthasasufficientreality，whenitsBeingisuninterrupted，andindependentoftheincessantrevolutions，whichweareconsciousofinourselves。
ThustoresumewhatIhavesaidconcerningthesenses；theygiveusnonotionofcontinu’dexistence，becausetheycannotoperatebeyondtheextent，inwhichtheyreallyoperate。Theyaslittleproducetheopinionofadistinctexistence，becausetheyneithercanofferittothemindasrepresented，norasoriginal。Toofferitasrepresented，theymustpresentbothanobjectandanimage。Tomakeitappearasoriginal，theymustconveyafalshood；andthisfalshoodmustlieintherelationsandsituation:Inordertowhichtheymustbeabletocomparetheobjectwithourselves；andeveninthatcasetheydonot，norisitpossibletheyshou’d，deceiveus。Wemay，therefore，concludewithcertainty，thattheopinionofacontinu’dandofadistinctexistenceneverarisesfromthesenses。
Toconfirmthiswemayobserve，thattherearethreedifferentkindsofimpressionsconvey’dbythesenses。The-firstarethoseofthefigure，bulk，motionandsolidityofbodies。Thesecondthoseofcolours，tastes，smells，sounds，heatandcold。Thethirdarethepainsandpleasures，thatarisefromtheapplicationofobjectstoourbodies，asbythecuttingofourfleshwithsteel，andsuchlike。Bothphilosophersandthevulgarsupposethefirstofthesetohaveadistinctcontinu’dexistence。Thevulgaronlyregardthesecondasonthesamefooting。Bothphilosophersandthevulgar，again，esteemthethirdtobemerelyperceptionsandconsequentlyinterruptedanddependentbeings。
Now’tisevident，that，whatevermaybeourphilosophicalopinion，colours，Sounds，heatandcold，asfarasappearstothesenses，existafterthesamemannerwithmotionandsolidity，andthatthedifferencewemakebetwixttheminthisrespect，arisesnotfromthemereperception。Sostrongtheprejudiceforthedistinctcontinu’dexistenceOftheformerqualities，thatwhenthecontraryopinionisadvanc’dbymodernphilosophers，peopleimaginetheycanalmostrefuteitfromtheirfeelingandexperience，andthattheirverysensescontradictthisphilosophy。’Tisalsoevident，thatcolours，sounds，&；c。areoriginallyonthesamefootingwiththepainthatarisesfromsteel，andpleasurethatproceedsfromafire；andthatthedifferencebetwixtthemisfoundedneitheronperceptionnorreason，butontheimagination。Forastheyareconfesttobe，bothofthem，nothingbutperceptionsarisingfromtheparticularconfigurationsandmotionsofthepartsofbody，whereinpossiblycantheirdifferenceconsist？Uponthewhole，then，wemayconclude，thatasfarasthesensesarejudges，allperceptionsarethesameinthemanneroftheirexistence。
Wemayalsoobserveinthisinstanceofsoundsandcolours，thatwecanattributeadistinctcontinu’dexistencetoobjectswithouteverconsultingREASON，orweighingouropinionsbyanyphilosophicalprinciples。Andindeed，whateverconvincingargumentsphilosophersmayfancytheycanproducetoestablishthebeliefofobjectsindependentofthemind，’tisobvioustheseargumentsareknownbuttoveryfew，andthat’tisnotbythem，thatchildren，peasants，andthegreatestpartofmankindareinduc’dtoattributeobjectstosomeimpressions，anddenythemtoothers。Accordinglywefind，thatalltheconclusions，whichthevulgarformonthishead，aredirectly’contrarytothose，whichareconfirm’dbyphilosophy。Forphilosophyinformsus，thateverything，whichappearstothemind，isnothingbutaperception，andisinterrupted，anddependentonthemind:whereasthevulgarconfoundperceptionsandobjects，andattributeadistinctcontinu’dexistencetotheverythingstheyfeelorsee。Thissentiment，then，asitisentirelyunreasonable，mustproceedfromsomeotherfacultythantheunderstanding。Towhichwemayadd，thataslongaswetakeourperceptionsandobjectstobethesame，wecanneverinfertheexistenceoftheonefromthatoftheother，norformanyargumentfromtherelationofcauseandeffect；whichis。theonlyonethatearlassureusofmatteroffact。Evenafterwedistinguishourperceptionsfromourobjects，’twillappearpresently，thatwearestillincapableofreasoningfromtheexistenceofonetothatoftheother:Sothatuponthewholeourreasonneitherdoes，norisitpossibleitevershou’d，uponanysupposition，giveusanassuranceofthecontinu’danddistinctexistenceofbody。ThatopinionmustbeentirelyowingtotheIMAGINATION:whichmustnowbethesubjectofourenquiry。
Sinceallimpressionsareinternalandperishingexistences，andappearassuch，thenotionoftheirdistinctandcontinu’dexistencemustarisefromaconcurrenceofsomeoftheirqualitieswiththequalitiesoftheimagination，andsincethisnotiondoesnotextendtoallofthem，itmustarisefromcertainqualitiespeculiartosomeimpressions。’Twillthereforebeeasyforustodiscoverthesequalitiesbyacomparisonoftheimpressions，towhichweattributeadistinctandcontinu’dexistence，withthose，whichweregardasinternalandperishing。
Wemayobserve，then，that’tisneitheruponaccountoftheinvoluntarinessofcertainimpressions，asiscommonlysuppos’d，noroftheirsuperiorforceandviolence，thatweattributetothemareality，andcontinu’dexistence，whichwerefusetoothers，thatarevoluntaryorfeeble。For’tisevidentourpainsandpleasures，ourpassionsandaffections，whichweneversupposetohaveanyexistencebeyondourperception，operatewithgreaterviolence，andareequallyinvoluntary，astheimpressionsoffigureandextension，colourandsound，whichwesupposetobepermanentbeings。Theheatofafire，whenmoderate，issuppos’dtoexistinthefire；butthepain，whichitcausesuponanearapproach，isnottakentohaveanybeing，exceptintheperception。
Thesevulgaropinions，then，beingrejected，wemustsearchforsomeotherhypothesis，bywhichwemaydiscoverthosepeculiarqualitiesinourimpressions，whichmakesusattributetothemadistinctandcontinu’dexistence。
Afteralittleexamination，weshallfind，thatallthoseobjects，towhichweattributeacontinu’dexistence，haveapeculiarconstancy，whichdistinguishesthemfromtheimpressions，whoseexistencedependsuponourperception。Thosemountains，andhouses，andtrees，whichlieatpresentundermyeye，havealwaysappear’dtomeinthesameorder；andwhenIlosesightofthembyshuttingmyeyesorturningmyhead，Isoonafterfindthemreturnuponmewithouttheleastalteration。Mybedandtable，mybooksandpapers，presentthemselvesinthesameuniformmanner，andchangenotuponaccountofanyinterruptioninmyseeingorperceivilngthem。Thisisthecasewithalltheimpressions，whoseobjectsaresuppos’dtohaveanexternalexistence；andisthecasewithnootherimpressions，whethergentleorviolent，voluntaryorinvoluntary。
Thisconstancy，however，isnotsoperfectasnottoadmitofveryconsiderableexceptions。Bodiesoftenchangetheirpositionandqualities，andafteralittleabsenceorinterruptionmaybecomehardlyknowable。Buthere’tisobservable，thateveninthesechangestheypreserveacoherence，andhavearegulardependenceoneachother；whichisthefoundationofakindofreasoningfromcausation，andproducestheopinionoftheircontinu’dexistence。WhenIreturntomychamberafteranhour’sabsence，Ifindnotmyfireinthesamesituation，inwhichIleftit:ButthenIamaccustomedinotherinstancestoseealikealterationproduc’dinaliketime，whetherIampresentorabsent，nearorremote。Thiscoherence，therefore，intheirchangesisoneofthecharacteristicsofexternalobjects，aswellastheirconstancy。
Havingfoundthattheopinionofthecontinu’dexistenceofbodydependsontheCOHERENCE，andCONSTANCYofcertainimpressions，Inowproceedtoexamineafterwhatmannerthesequalitiesgiverisetosoextraordinaryanopinion。Tobeginwiththecoherence；wemayobserve，thattho’thoseinternalimpressions，whichweregardasfleetingandperishing，havealsoacertaincoherenceorregularityintheirappearances，yet’tisofsomewhatadifferentnature，fromthatwhichwediscoverinbodies。’Ourpassionsarefoundbyexperiencetohaveamutualconnexionwithanddependenceoneachother；butonnooccasionisitnecessarytosuppose，thattheyhaveexistedandoperated，whentheywerenotperceiv’d，inordertopreservethesamedependenceandconnexion，ofwhichwehavehadexperience。Thecaseisnotthesamewithrelationtoexternalobjects。Thoserequireacontinu’dexistence，orotherwiselose，inagreatmeasure，theregularityoftheiroperation。Iamhereseatedinmychamberwithmyfacetothefire；andalltheobjects，thatstrikemysenses，arecontain’dinafewyardsaroundme。Mymemory，indeed，informsmeoftheexistenceofmanyobjects；butthenthisinformationextendsnotbeyondtheirpastexistence，nordoeithermysensesormemorygiveanytestimonytothecontinuanceoftheirbeing。WhenthereforeIamthusseated，andrevolveoverthesethoughts，Ihearonasuddenanoiseasofadoorturninguponitshinges；andalittleafterseeaporter，whoadvancestowardsme。Thisgivesoccasiontomanynewreflectionsandreasonings。First，Ineverhaveobserv’d，thatthisnoisecou’dproceedfromanythingbutthemotionofadoor；andthereforeconclude，thatthepresentphaenomenonisacontradictiontoallpastexperience，unlessthedoor，whichIrememberont’othersidethechamber，bestillinbeing。Again，Ihavealwaysfound，thatahumanbodywaspossestofaquality，whichIcallgravity，andwhichhindersitfrommountingintheair，asthisportermusthavedonetoarriveatmychamber，unlessthestairsIrememberbenotannihilatedbymyabsence。Butthisisnotall。Ireceivealetter，whichupon，openingitIperceivebythehand-writingandsubscriptiontohavecomefromafriend，whosaysheistwohundredleaguesdistant。’TisevidentIcanneveraccountforthisphenomenon，conformabletomyexperienceinotherinstances，withoutspreadingoutinmymindthewholeseaandcontinentbetweenus，andsupposingtheeffectsandcontinu’dexistenceofpostsandferries，accordingtomyMemoryandobservation。Toconsiderthesephaenomenaoftheporterandletterinacertainlight，theyarecontradictionstocommonexperience，andmayberegardedasobjectionstothosemaxims，whichweformconcerningtheconnexionsofcausesandeffects。Iamaccustomedtohearsuchasound，andseesuchanobjectinmotionatthesametime。Ihavenotreceiv’dinthisparticularinstanceboththeseperceptions。Theseobservationsarecontrary，unlessIsupposethatthedoorstillremains，andthatitwasopen’dwithoutmyperceivingit:Andthissupposition，whichwasatfirstentirelyarbitraryandhypothetical，acquiresaforceandevidencebyitsbeingtheonlyone，uponwhichIcanreconcilethesecontradictions。Thereisscarceamomentofmylife，whereinthereisnotasimilarinstancepresentedtome，andIhavenotoccasiontosupposethecontinu’dexistenceofobjects，inordertoconnecttheirpastandpresentappearances，andgivethemsuchanunionwitheachother，asIhavefoundbyexperiencetobesuitabletotheirparticularnaturesandcircumstances。HerethenIamnaturallyledtoregardtheworld，assomethingrealanddurable，andaspreservingitsexistence，evenwhenitisnolongerpresenttomyperception。
Buttho’thisconclusionfromthecoherenceofappearancesmayseemtobeofthesamenaturewithourreasoningsconcerningcausesandeffects；asbeingderiv’dfromcustom，andregulatedbypastexperience；weshallfinduponexamination，thattheyareatthebottomconsiderablydifferentfromeachother，andthatthisinferencearisesfromtheunderstanding，andfromcustominanindirectandobliquemanner。For’twillreadilybeallow’d，thatsincenothingiseverreallypresenttothemind，besidesitsownperceptions，’tisnotonlyimpossible，thatanyhabitshou’deverbeacquir’dotherwisethanbytheregularsuccessionoftheseperceptions，butalsothatanyhabitshou’deverexceedthatdegreeofregularity。Anydegree，therefore，ofregularityinourperceptions，canneverbeafoundationforustoinfera，greaterdegreeofregularityinsomeobjects，whicharenotperceiv’d；sincethissupposesacontradiction，viz。ahabitacquir’dbywhatwasneverpresenttothemind。’But’tisevident，thatwheneverweinferthecontinu’dexistenceoftheobjectsofsensefromtheircoherence，andthefrequencyoftheirunion，’tisinordertobestowontheobjectsagreaterregularitythanwhatisobserv’dinourmereperceptions。Weremarkaconnexionbetwixttwokindsofobjectsintheirpastappearancetothesenses，butarenotabletoobservethisconnexiontobeperfectlyconstant，sincetheturningaboutofourheadortheshuttingofoureyesisabletobreakit。Whatthendowesupposeinthiscase，butthattheseobjectsstillcontinuetheirusualconnexion，notwithstandingtheirapparentinterruption，andthattheirregularappearancesarejoin’dbysomething，ofwhichweareinsensible？Butasallreasoningconcerningmattersoffactarisesonlyfromcustom，andcustomcanonlybetheeffectofrepeatedperceptions，theextendingofcustomandreasoningbeyondtheperceptionscanneverbethedirectandnaturaleffectoftheconstantrepetitionandconnexion，butmustarisefromtheco-operationofsomeotherprinciples。
Ihavealreadyobserv’d，(33)inexaminingthefoundationofmathematics，thattheimagination，whensetintoanytrainofthinking，isapttocontinue，evenwhenitsobjectfailsit，andlikeagalleyputinmotionbytheoars，carriesonitscoursewithoutanynewimpulse。ThisIhaveassign’dforthereason，why，afterconsideringseveralloosestandardsofequality，andcorrectingthembyeachother，weproceedtoimaginesocorrectandexactastandardofthatrelation，asisnotliabletotheleasterrororvariation。Thesameprinciplemakesuseasilyentertainthisopinionofthecontinu’dexistenceofbody。Objectshaveacertaincoherenceevenastheyappeartooursenses；butthiscoherenceismuchgreaterandmoreuniform，ifwesupposetheobject。%tohaveacontinu’dexistence；andasthemindisonceinthetrainofobservinganuniformityamongobjects，itnaturallycontinues，tillitrenderstheuniformityascompleataspossible。Thesimplesuppositionoftheircontinu’dexistencesufficesforthispurpose，andgivesusanotionofamuchgreaterregularityamongobjects，thanwhattheyhavewhenwelooknofartherthanoursenses。
Butwhateverforcewemayascribetothisprinciple，Iamafraid’tistooweaktosupportalonesovastanedifice，asisthatofthecontinu’dexistenceofallexternalbodies；andthatwemustjointheconstancyoftheirappearancetothecoherence，inordertogiveasatisfactoryaccountofthatopinion。Astheexplicationofthiswillleadmeintoaconsiderablecompassofveryprofoundreasoning；Ithinkitproper，inordertoavoidconfusion，togiveashortsketchorabridgmentofmysystem，andafterwardsdrawoutallitspartsintheirfullcompass。Thisinferencefromtheconstancyofourperceptions，liketheprecedentfromtheircoherence，givesrisetotheopinionofthecontinu’dexistenceofbody，whichispriortothatofitsdistinctexistence，andproducesthatlatterprinciple。
Whenwehavebeenaccustomedtoobserveaconstancyincertainimpressions，andhavefound，thattheperceptionofthesunorocean，forinstance，returnsuponusafteranabsenceorannihilationwithlikepartsandinalikeorder，asatitsfirstappearance，wearenotapttoregardtheseinterruptedperceptionsasdifferent，(whichtheyreallyare)butonthecontraryconsiderthemasindividuallythesame，uponaccountoftheirresemblance。Butasthisinterruptionoftheirexistenceiscontrarytotheirperfectidentity，andmakesusregardthefirstimpressionasannihilated，andthesecondasnewlycreated，wefindourselvessomewhatataloss，andareinvolv’dinakindofcontradiction。Inordertofreeourselvesfromthisdifficulty，wedisguise，asmuchaspossible，theinterruption，orratherremoveitentirely，bysupposingthattheseinterruptedperceptionsareconnectedbyarealexistence，ofwhichweareinsensible。Thissupposition，orideaofcontinu’dexistence，acquiresaforceandvivacityfromthememoryofthesebrokenimpressions，andfromthatpropensity，whichtheygiveus，tosupposethemthesame；andaccordingtotheprecedentreasoning，theveryessenceofbeliefconsistsintheforceandvivacityoftheconception。
Inordertojustifythissystem，therearefourthingsrequisite。First，Toexplaintheprincipiumindividuationis，orprincipleofidentity。Secondly，Giveareason，whytheresemblanceofourbrokenandinterruptedperceptionsinducesustoattributeanidentitytothem。，Accountforthatpropensity，whichthisillusiongives，tounitethesebrokenappearancesbyacontinuedexistence。Fourthlyandlastly，Explainthatforceandvivacityofconception，whicharisesfromthepropensity。
First，Astotheprincipleofindividuation；wemayobserve，thattheviewofanyoneobjectisnotsufficienttoconveytheideaofidentity。Forinthatproposition，anobjectisthesamewithitself，iftheideaexpress’dbytheword，object，werenowaysdistinguishedfromthatmeantbyitself；wereallyshou’dmeannothing，norwou’dthepropositioncontainapredicateandasubject，whichhoweverareimply’dinthisaffirmation。Onesingleobjectconveystheideaofunity，notthatofidentity。
Ontheotherhand，amultiplicityofobjectscanneverconveythisidea，howeverresemblingtheymaybesuppos’d。Themindalwayspronouncestheonenottobetheother，andconsidersthemasformingtwo，three，oranydeterminatenumberofobjects，whoseexistencesareentirelydistinctandindependent。
Sincethenbothnumberandunityareincompatiblewiththerelationofidentity，itmustlieinsomethingthatisneitherofthem。Buttotellthetruth，atfirstsightthisseemsutterlyimpossible。Betwixtunityandnumbertherecanbenomedium；nomorethanbetwixtexistenceandnonexistence。Afteroneobjectissuppos’dtoexist，wemusteithersupposeanotheralsotoexist；inwhichcasewehavetheideaofnumber:Orwemustsupposeitnottoexist；inwhichcasethefirstobjectremainsatunity。
Toremovethisdifficulty，letushaverecoursetotheideaoftimeorduration。Ihavealreadyobservd，(34)thattime，inastrictsense，impliessuccession，andthatwhenweapplyitsideatoanyunchangeableobject，’tisonlybyafictionoftheimagination，bywhichtheunchangeableobjectissupposdtoparticipateofthechangesoftheco-existentobjects，andinparticularofthatofourperceptions。Thisfictionoftheimaginationalmostuniversallytakesplace；and’tisbymeansofit，thatasingleobject，placdbeforeus，andsurveydforanytimewithoutourdiscoveringinitanyinterruptionorvariation，isabletogiveusanotionofidentity。Forwhenweconsideranytwopointsofthistime，wemayplacethemindifferentlights:Wemayeithersurveythemattheverysameinstant；inwhichcasetheygiveustheideaofnumber，bothbythemselvesandbytheobject；whichmustbemultiplyd，inordertobeconceivdatonce，asexistentinthesetwodifferentpointsoftime:Orontheotherhand，wemaytracethesuccessionoftimebyalikesuccessionofideas，andconceivingfirstonemoment，alongwiththeobjectthenexistent，imagineafterwardsachangeinthetimewithoutanyvariationorinterruptionintheobject；inwhichcaseitgivesustheideaofunity。Herethenisanidea，whichisamediumbetwixtunityand。number；ormoreproperlyspeaking，iseitherofthem，accordingtotheview，inwhichwetakeit:Andthisideawecallthatofidentity。Wecannot，inanyproprietyofspeech，say，thatanobjectisthesamewithitself，unlesswemean，thattheobjectexistentatonetimeisthesamewithitselfexistentatanother。Bythismeanswemakeadifference，betwixttheideameantbytheword，object，andthatmeantbyitself，withoutgoingthelengthofnumber，andatthesametimewithoutrestrainingourselvestoastrictandabsoluteunity。
Thustheprincipleofindividuationisnothingbuttheinvariablenessanduninterruptednessofanyobject，throasupposdvariationoftime，bywhichthemindcantraceitinthedifferentperiodsofitsexistence，withoutanybreakoftheview，andwithoutbeingobligdtoformtheideaofmultiplicityornumber。
Inowproceedtoexplainthesecondpartofmysystem，andshewwhytheconstancyofourperceptionsmakesusascribetothemaperfectnumericalidentity，thotherebeverylongintervalsbetwixttheirappearance，andtheyhaveonlyoneoftheessentialqualitiesofidentity，viz，invariableness。ThatImayavoidallambiguityandconfusiononthishead，Ishallobserve，thatIhereaccountfortheopinionsandbeliefofthevulgarwithregardtotheexistenceofbody；andthereforemustentirelyconformmyselftotheirmannerofthinkingandofexpressingthemselves。Nowwehavealreadyobservd，thathoweverphilosophersmaydistinguishbetwixttheobjectsandperceptionsofthesenses；whichtheysupposeco-existentandresembling；yetthisisadistinction，whichisnotcomprehendedbythegeneralityofmankind，whoastheyperceiveonlyonebeing，canneverassenttotheopinionofadoubleexistenceandrepresentation。Thoseverysensations，whichenterbytheeyeorear，arewiththemthetrueobjects，norcantheyreadilyconceivethatthispenorpaper，whichisimmediatelyperceivd，representsanother，whichisdifferentfrom，butresemblingit。Inorder，therefore，toaccommodatemyselftotheirnotions，Ishallatfirstsuppose；thatthereisonlyasingleexistence，whichIshallcallindifferentlyobjectorperception，accordingasitshallseembesttosuitmypurpose，understandingbybothofthemwhatanycommonmanmeansbyahat，orshoe，orstone，oranyotherimpression，conveydtohimbyhissenses。Ishallbesuretogivewarning，whenIreturntoamorephilosophicalwayofspeakingandthinking。
Toenter，therefore，uponthequestionconcerningthesourceoftheerroranddeceptionwithregardtoidentity，whenweattributeittoourresemblingperceptions，notwithstandingtheirinterruption；Imusthererecalanobservation，whichIhavealreadyprovdandexplaind。(35)Nothingismoreapttomakeusmistakeoneideaforan-other，thananyrelationbetwixtthem，whichassociatesthemtogetherintheimagination，andmakesitpasswithfacilityfromonetotheother。Ofallrelations，thatofresemblanceisinthisrespectthemostefficacious；andthatbecauseitnotonlycausesanassociationofideas，butalsoofdispositions，andmakesusconceivetheoneideabyanactoroperationofthemind，similartothatbywhichweconceivetheother。ThiscircumstanceIhaveobservdtobeofgreatmoment；andwemayestablishitforageneralrule，thatwhateverideasplacethemindinthesamedispositionorinsimilarones，areveryapttobeconfounded。Themindreadilypassesfromonetotheother，andperceivesnotthechangewithoutastrictattention，ofwhich，generallyspeaking，’tiswhollyincapable。
Inordertoapplythisgeneralmaxim，wemustfirstexaminethedispositionofthemindinviewinganyobjectwhichpreservesaperfectidentity，andthenfindsomeotherobject，thatisconfoundedwithit，bycausingasimilardisposition。Whenwefixourthoughtonanyobject，andsupposeittocontinuethesameforsometime；’tisevidentwesupposethechangetolieonlyinthetime，andneverexertourselvestoproduceanynewimageorideaoftheobject。Thefacultiesofthemindreposethemselvesinamanner，andtakenomoreexercise，thanwhatisnecessarytocontinuethatidea，ofwhichwewereformerlypossest，andwhichsubsistswithoutvariationorinterruption。Thepassagefromonemomenttoanotherisscarcefelt，anddistinguishesnotitselfbyadifferentperceptionoridea，whichmayrequireadifferentdirectionofthespirits，inordertoitsconception。
Nowwhatotherobjects，besideidenticalones，arecapableofplacingthemindinthesamedisposition，whenitconsidersthem，andofcausingthesameuninterruptedpassageoftheimaginationfromoneideatoanother？Thisquestionisofthelastimportance。Forifwecanfindanysuchobjects，wemaycertainlyconclude，fromtheforegoingprinciple，thattheyareverynaturallyconfoundedwithidenticalones，andaretakenfortheminmostofourreasonings。Buttho’thisquestionbeveryimportant，’tisnotverydifficultnordoubtful。ForIimmediatelyreply，thatasuccessionofrelatedobjectsplacesthemindinthisdisposition，andisconsider’dwiththesamesmoothanduninterruptedprogressoftheimagination，asattendstheviewofthesameinvariableobject。Theverynatureandessenceofrelationistoconnectourideaswitheachother，andupontheappearanceofone，tofacilitatethetransitiontoitscorrelative。Thepassagebetwixtrelatedideasis，therefore，sosmoothandeasy，thatitproduceslittlealterationonthemind，andseemslikethecontinuationofthesameaction；andasthecontinuationofthesameactionisaneffectofthecontinu’dviewofthesameobject，’tisforthisreasonweattributesamenesstoeverysuccessionofrelatedobjects。Thethoughtslidesalongthesuccessionwithequalfacility，asifitconsider’donlyoneobject；andthereforeconfoundsthesuccessionwiththeidentity。
Weshallafterwardsseemanyinstancesofthistendencyofrelationtomakeusascribeanidentitytodifferentobjects；butshallhereconfineourselvestothepresentsubject。Wefindbyexperience，thatthereissuchaconstancyinalmostalltheimpressionsofthesenses，thattheirinterruptionproducesnoalterationonthem，andhindersthemnotfromreturningthesameinappearanceandinsituationasattheirfirstexistence。Isurveythefurnitureofmychamber；Ishutmyeyes，andafterwardsopenthem；andfindthenewperceptionstoresembleperfectlythose，whichformerlystruckmysenses。Thisresemblanceisobserv’dinathousandinstances，andnaturallyconnectstogetherourideasoftheseinterruptedperceptionsbythestrongestrelation。andconveysthemindwithaneasytransitionfromonetoanother……kneasytransitionorpassageoftheimagination，alongtheideasofthesedifferentandinterruptedperceptions，isalmostthesamedispositionofmindwiththatinwhichweconsideroneconstantanduninterruptedperception。’Tisthereforeverynaturalforustomistaketheonefortheother。(36)
Thepersons，whoentertainthisopinionconcerningtheidentityofourresemblingperceptions，areingeneralantheunthinkingandunphilosophicalpartofmankind，(thatis，allofus，atonetimeorother)andconsequentlysuchassupposetheirperceptionstobetheironlyobjects，andneverthinkofadoubleexistenceinternalandexternal，representingandrepresented。Theveryimage，whichispresenttothesenses，iswithustherealbody；and’tistotheseinterruptedimagesweascribeaperfectidentity。Butastheinterruptionoftheappearanceseemscontrarytotheidentity，andnaturallyleadsustoregardtheseresemblingperceptionsasdifferentfromeachother，weherefindourselvesatalosshowtoreconcilesuchoppositeopinions。Thesmoothpassageoftheimaginationalongtheideasoftheresemblingperceptionsmakesusascribetothemaperfectidentity。Theinterruptedmanneroftheirappearancemakesusconsiderthemassomanyresembling，butstilldistinctbeings，whichappearaftercertainintervals。Theperplexityarisingfromthiscontradictionproducesapropensiontounitethesebrokenappearancesbythefictionofacontinu’dexistence，whichisthethirdpartofthathypothesisIpropos’dtoexplain。
Nothingismorecertainfromexperience，thanthatanycontradictioneithertothesentimentsorpassionsgivesasensibleuneasiness，whetheritproceedsfromwithoutorfromwithin；fromtheoppositionofexternalobjects，orfromthecombatofinternalprinciples。Onthecontrary，whateverstrikesinwiththenaturalpropensities，andeitherexternallyforwardstheirsatisfaction，orinternallyconcurswiththeirmovements，issuretogiveasensiblepleasure。Nowtherebeinghereanoppositionbetwixtthenotionoftheidentityofresemblingperceptions，andtheinterruptionoftheirappearance，themindmustbeuneasyinthatsituation，andwillnaturallyseekrelieffromtheuneasiness。Sincetheuneasinessarisesfromtheoppositionoftwocontraryprinciples，itmustlookforreliefbysacrificingtheonetotheother。Butasthesmoothpassageofourthoughtalongourresemblingperceptionsmakesusascribetothemanidentity，wecanneverwithoutreluctanceyieldupthatopinion。Wemust，therefore，turntotheotherside，andsupposethatourperceptionsarenolongerinterrupted，butpreserveacontinu’daswellasaninvariableexistence，andarebythatmeansentirelythesame。Butheretheinterruptionsintheappearanceoftheseperceptionsaresolongandfrequent，that’tisimpossibletooverlookthem；andastheappearanceofaperceptioninthemindanditsexistenceseematfirstsightentirelythesame，itmaybedoubted，whetherwecaneverassenttosopalpableacontradiction，andsupposeaperceptiontoexistwithoutbeingpresenttothemind。Inordertoclearupthismatter，andlearnhowtheinterruptionintheappearanceofaperceptionimpliesnotnecessarilyaninterruptioninitsexistence，’twillbepropertotouchuponsomeprinciples，whichweshallhaveoccasiontoexplainmorefullyafterwards。(37)
Wemaybeginwithobserving，thatthedifficultyinthepresentcaseisnotconcerningthematteroffact，orwhetherthemindformssuchaconclusionconcerningthecontinu’dexistenceofitsperceptions，butonlyconcerningthemannerinwhichtheconclusionisform’d，andprinciplesfromwhichitisderiv’d。’Tiscertain，thatalmostallmankind，andevenphilosophersthemselves，forthegreatestpartoftheirlives，taketheirperceptionstobetheironlyobjects，andsuppose，thattheverybeing，whichisintimatelypresenttothemind，istherealbodyormaterialexistence。’Tisalsocertain，thatthisveryperceptionorobjectissuppos’dtohaveacontinu’duninterruptedbeing，andneithertobeannihilatedbyourabsence，nortobebroughtintoexistencebyourpresence。Whenweareabsentfromit，wesayitstillexists，butthatwedonotfeel，wedonotseeit。Whenwearepresent，wesaywefeel，orseeit。Herethenmayarisetwoquestions；First，Howwecansatisfyourselvesinsupposingaperceptiontobeabsentfromthemindwithoutbeingannihilated。Secondly，Afterwhatmannerweconceiveanobjecttobecomepresenttothemind，withoutsomenewcreationofaperceptionorimage；andwhatwemeanbythisseeing，andfeeling，andperceiving。
Astothefirstquestion；wemayobserve，thatwhatwe。callamind，isnothingbutaheaporcollectionofdifferentperceptions，unitedtogetherbycertainrelations，andsuppos’d，tho’falsely，tobeendow’dwithaperfectsimplicityandidentity。Nowaseveryperceptionisdistinguishablefromanother，andmaybeconsideredasseparatelyexistent；itevidentlyfollows，thatthereisnoabsurdityinseparatinganyparticularperceptionfromthemind；thatis，inbreakingoffallitsrelations，withthatconnectedmassofperceptions，whichconstituteathinkingbeing。
Thesamereasoningaffordsusananswertothesecondquestion。Ifthenameofperceptionrendersnotthisseparationfromamindabsurdandcontradictory，thenameofobject，standingfortheverysamething，canneverrendertheirconjunctionimpossible。Externalobjectsareseen，andfelt，andbecomepresenttothemind；thatis，theyacquiresucharelationtoaconnectedheapofperceptions，astoinfluencethemveryconsiderablyinaugmentingtheirnumberbypresentreflectionsandpassions，andinstoringthememorywithideas。Thesamecontinu’danduninterruptedBeingmay，therefore，besometimespresenttothemind，andsometimesabsentfromit，withoutanyrealoressentialchangeintheBeingitself。Aninterruptedappearancetothesensesimpliesnotnecessarilyaninterruptionintheexistence。Thesuppositionofthecontinu’dexistenceofsensibleobjectsorperceptionsinvolvesnocontradiction。Wemayeasilyindulgeourinclinationtothatsupposition。Whentheexactresemblanceofourperceptionsmakesusascribetothemanidentity，wemayremovetheseeminginterruptionbyfeigningacontinu’dbeing，whichmayfillthoseintervals，andpreserveaperfectandentireidentitytoourperceptions。
Butasweherenotonlyfeignbutbelievethiscontinu’dexistence，thequestionis，fromwhencearisessuchabelief；andthisquestionleadsustothefourthmemberofthissystem。Ithasbeenprov’dalready，thatbeliefingeneralconsistsinnothing，butthevivacityofanidea；andthatanideamayacquirethisvivacitybyitsrelationtosomepresentimpression。Impressionsarenaturallythemostvividperceptionsofthemind；andthisqualityisinpartconvey’dbytherelationtoeveryconnectedidea。Therelationcausesasmoothpassagefromtheimpressiontotheidea，andevengivesapropensitytothatpassage。Themindfallssoeasilyfromtheoneperceptiontotheother，thatitscarceperceivesthechange，butretainsinthesecondaconsiderableshareofthevivacityofthefirst。Itisexcitedbythelivelyimpression；andthisvivacityisconvey’dtotherelatedidea，withoutanygreatdiminutioninthepassage，byreasonofthesmoothtransitionandthepropensityoftheimagination。
Butsuppose，thatthispropensityarisesfromsomeotherprinciple，besidesthatofrelation；’tisevidentitmuststillhavethesameeffect，andconveythevivacityfromtheimpressiontotheidea。Nowthisisexactlythepresentcase。Ourmemorypresentsuswithavastnumberofinstancesofperceptionsperfectlyresemblingeachother，thatreturnatdifferentdistancesoftime，andafterconsiderableinterruptions。Thisresemblancegivesusapropensiontoconsidertheseinterruptedperceptionsasthesame；andalsoapropensiontoconnectthembyacontinu’dexistence，inordertojustifythisidentity，andavoidthecontradiction，inwhichtheinterruptedappearanceoftheseperceptionsseemsnecessarilytoinvolveus。Herethenwehaveapropensitytofeignthecontinu’dexistenceofallsensibleobjects；andasthispropensityarisesfromsomelivelyimpressionsofthememory，itbestowsavivacityonthatfiction:orinotherwords，makesusbelievethecontinu’dexistenceofbody。Ifsometimesweascribeacontinu’dexistencetoobjects，whichareperfectlynewtous，andofwhoseconstancyandcoherencewehavenoexperience，’tisbecausethemanner，inwhichtheypresentthemselvestooursenses，resemblesthatofconstantandcoherentobjects；andthisresemblanceisasourceofreasoningandanalogy，andleadsustoattributethesamequalitiestosimilarobjects。
Ibelieveanintelligentreaderwillfindlessdifficultytoassenttothissystem，thantocomprehenditfullyanddistinctly，andwillallow，afteralittlereflection，thateverypartcarriesitsownproofalongwithit。’Tisindeedevident，thatasthevulgarsupposetheirperceptionstobetheironlyobjects，andatthesametimebelievethecontinu’dexistenceofmatter，wemustaccountfortheoriginofthebeliefuponthatsupposition。Nowuponthatsupposition，’tisafalseopinionthatanyofourobjects，orperceptions，areidenticallythesameafteraninterruption；andconsequentlytheopinionoftheiridentitycanneverarisefromreason，butmustarisefromtheimagination。Theimaginationisseduc’dintosuchanopiniononlybymeansoftheresemblanceofcertainperceptions；sincewefindtheyareonlyourresemblingperceptions，whichwehaveapropensiontosupposethesame。Thispropensiontobestowanidentityonourresemblingperceptions，producesthefictionofacontinu’dexistence；sincethatfiction，aswellastheidentity，isreallyfalse，asisacknowledgedbyallphilosophers，andhasnoothereffectthantoremedytheinterruptionofourperceptions，whichistheonlycircumstancethatiscontrarytotheiridentity。Inthelastplacethispropensioncausesbeliefbymeansofthepresentimpressionsofthememory；sincewithouttheremembranceofformersensations，’tisplainwenevershou’dhaveanybeliefofthecontinu’dexistenceofbody。Thusinexaminingalltheseparts，wefindthateachofthemissupportedbythestrongestproofs:andthatallofthemtogetherformaconsistentsystem，whichisperfectlyconvincing。Astrongpropensityorinclinationalone，withoutanypresentimpression，willsometimescauseabelieforopinion。Howmuchmorewhenaidedbythatcircumstance？
Buttho’weareledafterthismanner，bythenaturalpropensityoftheimagination，toascribeacontinu’dexistencetothosesensibleobjectsorperceptions，whichwefindtoresembleeachotherintheirinterruptedappearance；yetaverylittlereflectionandphilosophyissufficienttomakeusperceivethefallacyofthatopinion。Ihavealreadyobserv’d，thatthereisanintimateconnexionbetwixtthosetwoprinciples，ofacontinu’dandofadistinctorindependentexistence，andthatwenosoonerestablishtheonethantheotherfollows，asanecessaryconsequence。’Tistheopinionofacontinu’dexistence，whichfirsttakesplace，andwithoutmuchstudyorreflectiondrawstheotheralongwithit，whereverthemindfollowsitsfirstandmostnaturaltendency。Butwhenwecompareexperiments，andreasonalittleuponthem，wequicklyperceive，thatthedoctrineoftheindependentexistenceofoursensibleperceptionsiscontrarytotheplainestexperience。Thisleadsusbackwarduponourfootstepstoperceiveourerrorinattributingacontinu’dexistencetoourperceptions，andistheoriginofmanyverycuriousopinions，whichweshallhereendeavourtoaccountfor。
’Twillfirstbepropertoobserveafewofthoseexperiments，whichconvinceus，thatourperceptionsarenotpossestofanyindependentexistence。Whenwepressoneeyewithafinger，weimmediatelyperceivealltheobjectstobecomedouble，andonehalfofthemtoberemov’dfromtheircommonandnaturalposition。Butaswedonotattributetocontinu’dexistencetoboththeseperceptions，andastheyarebothofthesamenature，weclearlyperceive，thatallourperceptionsaredependentonourorgans，andthedispositionofournervesandanimalspirits。Thisopinionisconfirm’dbytheseemingencreaseanddiminutionofobjects，accordingtotheirdistance；bytheapparentalterationsintheirfigure；bythechangesintheircolourandotherqualitiesfromoursicknessanddistempers:andbyaninfinitenumberofotherexperimentsofthesamekind；fromallwhichwelearn，thatoursensibleperceptionsarenotpossestofanydistinctorindependentexistence。
Thenaturalconsequenceofthisreasoningshou’dbe，thatourperceptionshavenomoreacontinuedthananindependentexistence；andindeedphilosophershavesofarrunintothisopinion，thattheychangetheirsystem，anddistinguish，(asweshalldoforthefuture)betwixtperceptionsandobjects，ofwhichtheformeraresuppos’dtobeinterrupted，andperishing，anddifferentateverydifferentreturn；thelattertobeuninterrupted，andtopreserveacontinu’dexistenceandidentity。Buthoweverphilosophicalthisnewsystemmaybeesteem’d，Iassertthat’tisonlyapalliativeremedy，andthatitcontainsallthedifficultiesofthevulgarsystem，withsomeothers，thatarepeculiartoitself。Therearenoprincipleseitheroftheunderstandingorfancy，whichleadusdirectlytoembracethisopinionofthedoubleexistenceofperceptionsandobjects，norcanwearriveatitbutbypassingthro’thecommonhypothesisoftheidentityandcontinuanceofourinterruptedperceptions。Werewenotfirstperswaded，thatourperceptionsareouronlyobjects，andcontinuetoexistevenwhentheynolongermaketheirappearancetothesenses，weshou’dneverbeledtothink，thatourperceptionsandobjectsaredifferent，andthatourobjectsalonepreserveacontinu’dexistence。’Thelatterhypothesishasnoprimaryrecommendationeithertoreasonortheimagination，butacquiresallitsinfluenceontheimaginationfromtheformer。’Thispropositioncontainstwoparts，whichweshallendeavourtoproveasdistinctlyandclearly，assuchabstrusesubjectswillpermit。
Astothefirstpartoftheproposition，thatthisphilosophicalhypothesishasnoprimaryrecommendation，，eithertoreason，ortheimagination，wemaysoonsatisfyourselveswithregardtoreasonbythefollowingreflections。Theonlyexistences，ofwhichwearecertain，areperceptions，whichbeingimmediatelypresenttousbyconsciousness，commandourstrongestassent，andarethefirstfoundationofallourconclusions。Theonlyconclusionwecandrawfromtheexistenceofonethingtothatofanother，isbymeansoftherelationofcauseandeffect，whichshews，thatthereisaconnexionbetwixtthem，andthattheexistenceofoneisdependentonthatoftheother。Theideaofthisrelationisderiv’dfrompastexperience，bywhichwefind，thattwobeingsareconstantlyconjoin’dtogether，andarealwayspresentatoncetothemind。Butasnobeingsareeverpresenttothemindbutperceptions；itfollowsthatwemayobserveacon。unctionorarelationofcauseandeffectbetweendifferentperceptions，butcanneverobserveitbetweenperceptionsandobjects。’Tisimpossible，therefore，thatfromtheexistenceoranyofthequalitiesoftheformer，wecaneverformanyconclusionconcerningtheexistenceofthelatter，oreversatisfyourreasoninthisparticular。
’Tisnolesscertain，thatthisphilosophicalsystemhasnoprimaryrecommendationtotheimagination，andthatthatfacultywou’dnever，ofitself，andbyitsoriginaltendency，havefallenuponsuchaprinciple。Iconfessitwillbesomewhatdifficulttoprovethistothefallsatisfactionofthereader；becauseitimpliesanegative，whichinmanycaseswillnotadmitofanypositiveproof。Ifanyonewou’dtakethepainstoexaminethisquestion，andwou’dinventasystem，toaccountforthedirectoriginofthisopinionfromtheimagination，weshou’dbeable，bytheexaminationofthatsystem，topronounceacertainjudgmentinthepresentsubject。Letitbetakenforgranted，thatourperceptionsarebroken，andinterrupted，andhoweverlike，arestilldifferentfromeachother；andletanyoneuponthissuppositionshewwhythefancy，directlyandimmediately，proceedstothebeliefofanotherexistence，resemblingtheseperceptionsintheirnature，butyetcontinu’d，anduninterrupted，andidentical；andafterhehasdonethistomysatisfaction，Ipromisetorenouncemypresentopinion。MeanwhileIcannotforbearconcluding，fromtheveryabstractednessanddifficultyofthefirstsupposition，that’tisanimpropersubjectforthefancytoworkupon。Whoeverwou’dexplaintheoriginofthecommonopinionconcerningthecontinu’danddistinctexistenceofbody，musttakethemindinitscommonsituation，andmustproceeduponthesupposition，thatourperceptionsareouronlyobjects，andcontinuetoexistevenwhentheyarenotperceiv’d。Tho’thisopinionbefalse，’tisthemostnaturalofany，andhasaloneanyprimaryrecommendationtothefancy。
Astothesecondpartoftheproposition，thatthephilosophicalsystemacquiresallitsinfluenceontheimaginationfromthevulgarone；wemayobserve，thatthisisanaturalandunavoidableconsequenceoftheforegoingconclusion，thatithasnoprimaryrecommendationtoreasonortheimagination。Forasthephilosophicalsystemisfoundbyexperiencetotakeholdofmanyminds，andinparticularofallthose，whoreflecteversolittleonthissubject，itmustderiveallitsauthorityfromthevulgarsystem；sinceithasnooriginalauthorityofitsown。Themanner，inwhichthesetwosystems，tho’directlycontrary，areconnectedtogether，maybeexplains，asfollows。
Theimaginationnaturallyrunsoninthistrainofthinking。Ourperceptionsareouronlyobjects:Resemblingperceptionsarethesame，howeverbrokenoruninterruptedintheirappearance:Thisappealinginterruptioniscontrarytotheidentity:Theinterruptionconsequentlyextendsnotbeyondtheappearance，andtheperceptionorobjectreallycontinuestoexist，evenwhenabsentfromus:Oursensibleperceptionshave，therefore，acontinu’danduninterruptedexistence。Butasalittlereflectiondestroysthisconclusion，thatourperceptionshaveacontinu’dexistence，byshewingthattheyhaveadependentone，’twou’dnaturallybeexpected，thatwemustaltogetherrejecttheopinion，thatthereissuchathinginnatureasacontinu’dexistence，whichispreserv’devenwhenitnolongerappearstothesenses。Thecase，however，isotherwise。Philosophersaresofarfromrejectingtheopinionofacontinu’dexistenceuponrejectingthatoftheindependenceandcontinuanceofoursensibleperceptions，thattho’allsectsagreeinthelattersentiment，theformer，whichis，inamanner，itsnecessaryconsequence，hasbeenpeculiartoafewextravagantsceptics；whoafterallmaintainedthatopinioninwordsonly，andwereneverabletobringthemselvessincerelytobelieveit。
Thereisagreatdifferencebetwixtsuchopinionsasweformafteracalmandprofoundreflection，andsuchasweembracebyakindofinstinctornaturalimpulse，onaccountoftheirsuitablenessandconformitytothemind。Iftheseopinionsbecomecontrary，’tisnotdifficulttoforeseewhichofthemwillhavetheadvantage。Aslongasourattentionisbentuponthesubject，thephilosophicalandstudy’dprinciplemayprevail；butthemomentwerelaxourthoughts，naturewilldisplayherself，anddrawusbacktoourformeropinion。Nayshehassometimessuchaninfluence，thatshecanstopourprogress，eveninthemidstofourmostprofoundreflections，andkeepusfromrunningonwithalltheconsequencesofanyphilosophicalopinion。Thustho’weclearlyperceivethedependenceandinterruptionofourperceptions，westopshortinourcareer，andneveruponthataccountrejectthenotionofanindependentandcontinu’dexistence。Thatopinionhastakensuchdeeprootintheimagination，that’tisimpossibleevertoeradicateit，norwillanystrain’dmetaphysicalconvictionofthedependenceofourperceptionsbesufficientforthatpurpose。
Buttho’ournaturalandobviousprincipleshereprevailaboveourstudy’dreflections，’tiscertaintheremustbesonicstruggleandoppositioninthecase:atleastsolongastheserejectionsretainanyforceorvivacity。Inordertosetourselvesateaseinthisparticular，wecontriveanewhypothesis，whichseemstocomprehendboththeseprinciplesofreasonandimagination。Thishypothesisisthephilosophical，oneofthedoubleexistenceofperceptionsandobjects；whichpleasesourreason，inallowing，thatourdependentperceptionsareinterruptedanddifferent；andatthesametimeisagreeabletotheimagination，inattributingacontinu’dexistencetosomethingelse，whichwecallobjects。Thisphilosophicalsystem，therefore，isthemonstrousoffspringoftwoprinciples，whicharecontrarytoeachother，whicharebothatonceembrac’dbythemind，andwhichareunablemutuallytodestroyeachother。Theimaginationtellsus，thatourresemblingperceptionshaveacontinu’danduninterruptedexistence，andarenotannihilatedbytheirabsence。Reflectiontellsus，thatevenourresemblingperceptionsareinterruptedintheirexistence，anddifferentfromeachother。Thecontradictionbetwixttheseopinionsweeludebyanewfiction，whichisconformabletothehypothesesbothofreflectionandfancy，byascribingthesecontraryqualitiestodifferentexistences；theinterruptiontoperceptions，andthecontinuancetoobjects。Natureisobstinate，andwillnotquitthefield，howeverstronglyattack’dbyreason；andatthesametimereasonissoclearinthepoint，thatthereisnopossibilityofdisguisingher。Notbeingabletoreconcilethesetwoenemies，weendeavourtosetourselvesateaseasmuchaspossible，bysuccessivelygrantingtoeachwhateveritdemands，andbyfeigningadoubleexistence，whereeachmayfindsomething，thathasalltheconditionsitdesires。Werewefullyconvinc’d，thatourresemblingperceptionsarecontinu’d，andidentical，andindependent，weshou’dneverrunintothisopinionofadoubleexistence。sinceweshou’dfindsatisfactioninourfirstsupposition，andwou’dnotlookbeyond。Again，werewefullyconvinc’d，thatourperceptionsaredependent，andinterrupted，anddifferent，weshou’dbeaslittleinclin’dtoembracetheopinionofadoubleexistence；sinceinthatcaseweshou’dclearlyperceivetheerrorofourfirstsuppositionofacontinu’dexistence，andwou’dneverregarditanyfarther。’Tisthereforefromtheintermediatesituationofthemind，thatthisopinionarises，andfromsuchanadherencetothesetwocontraryprinciples，asmakesusseeksomepretexttojustifyourreceivingboth；whichhappilyatlastisfoundinthesystemofadoubleexistence。
Anotheradvantageofthisphilosophicalsystemisitssimilaritytothevulgarone；bywhichmeanswecanhumourourreasonforamoment，whenitbecomestroublesomeandsollicitous；andyetuponitsleastnegligenceorinattention，caneasilyreturntoourvulgarandnaturalnotions。Accordinglywefind，thatphilosophersneglectnotthisadvantage；butimmediatelyuponleavingtheirclosets，minglewiththerestofmankindinthoseexplodedopinions，thatourperceptionsareouronlyobjects，andcontinueidenticallyanduninterruptedlythesameinalltheirinterruptedappearances。
Thereareotherparticularsofthissystem，whereinwemayremarkitsdependenceonthefancy，inaveryconspicuousmanner。Ofthese，Ishallobservethetwofollowing。First，Wesupposeexternalobjectstoresembleinternalperceptions。Ihavealreadyshewn，thattherelationofcauseandeffectcanneveraffordusanyjustconclusionfromtheexistenceorqualitiesofourperceptionstotheexistenceofexternalcontinu’dobjects:AndIshallfartheradd，thateventho’theycou’daffordsuchaconclusion，weshou’dneverhaveanyreasontoinfer，thatourobjectsresembleourperceptions。Thatopinion，therefore，isderiv’dfromnothingbutthequalityofthefancyabove-explain’d，。Wenevercanconceiveanythingbutperceptions，andthereforemustmakeeverythingresemblethem。
Secondly，Aswesupposeourobjectsingeneraltoresembleourperceptions，sowetakeitforgranted，thateveryparticularobjectresemblesthatperception，whichitcauses。Therelationofcauseandeffectdeterminesustojointheotherofresemblance；andtheideasoftheseexistencesbeingalreadyunitedtogetherinthefancybytheformerrelation，wenaturallyaddthelattertocompleattheunion。Wehaveastrongpropensitytocompleateveryunionbyjoiningnewrelationstothosewhichwehavebeforeobserv’dbetwixtanyideas，asweshallhaveoccasiontoobservepresently。(38)
Havingthusgivenanaccountofallthesystemsbothpopularandphilosophical，withregardtoexternalexistences，Icannotforbeargivingventtoacertainsentiment，whicharisesuponreviewingthosesystems。Ibegunthissubjectwithpremising，thatweoughttohaveanimplicitfaithinoursenses，andthatthiswou’dbetheconclusion，Ishou’ddrawfromthewholeofmyreasoning。Buttobeingenuous，Ifeelmyselfatpresentofaquitecontrarysentiment，andammoreinclin’dtoreposenofaithatallinmysenses，orratherimagination，thantoplaceinitsuchanimplicitconfidence。Icannotconceivebowsuchtrivialqualitiesofthefancy，conductedbysuchfalsesuppositions，caneverleadtoanysolidandrationalsystem。Theyarethecoherenceandconstancyofourperceptions，whichproducetheopinionoftheircontinu’dexistence；tho’thesequalitiesofperceptionshavenoperceivableconnexionwithsuchanexistence。Theconstancyofour]perceptionshasthemostconsiderableeffect，andyetisattendedwiththegreatestdifficulties。’Tisagrossillusiontosuppose，thatourresemblingperceptionsarenumericallythesame；and’tisthisillusion，whichleadsusintotheopinion，thattheseperceptionsareuninterrupted，andarestillexistent，evenwhentheyarenotpresenttothesenses。Thisisthecasewithourpopularsystem。Andastoourphilosophicalone，’tisliabletothesamedifficulties；andisover-and-aboveloadedwiththisabsurdity，thatitatoncedeniesandestablishesthevulgarsupposition。Philosophersdenyourresemblingperceptionstobeidenticallythesame，anduninterrupted；andyethavesogreatapropensitytobelievethemsuch，thattheyarbitrarilyinventanewsetofperceptions，towhichtheyattributethesequalities。Isay，anewsetofperceptions:Forwemaywellsupposeingeneral，but’tisimpossibleforusdistinctlytoconceive，objectstobeintheirnatureanythingbutexactlythesamewithperceptions。Whatthencanwelookforfromthisconfusionofgroundlessandextraordinaryopinionsbuterrorandfalshood？Andhowcanwejustifytoourselvesanybeliefwereposeinthem？
Thisscepticaldoubt，bothwithrespecttoreasonandthesenses，isamalady，whichcanneverberadicallycur’d，butmustreturnuponuseverymoment，howeverwemaychaceitaway，andsometimesmayseementirelyfreefromit。’Tisimpossibleuponanysystemtodefendeitherourunderstandingorsenses；andwebutexposethemfartherwhenweendeavourtojustifytheminthatmanner。Asthescepticaldoubtarisesnaturallyfromaprofoundandintensereflectiononthosesubjects，italwaysencreases，thefartherwecarryourreflections，whetherinoppositionorconformitytoit。Carelessnessandin-attentionalonecanaffordusanyremedy。ForthisreasonIrelyentirelyuponthem；andtakeitforgranted，whatevermaybethereader’sopinionatthispresentmoment，thatanhourhencehewillbepersuadedthereisbothanexternalandinternalworld；andgoinguponthatsupposition，Iintendtoexaminesomegeneralsystemsbothancientandmodern，whichhavebeenpropos’dofboth，beforeIproceedtoamoreparticularenquiryconcerningourimpressions。Thiswillnot，perhaps，intheendbefoundforeigntoourpresentpurpose。
