OfUnphilosophicalProbability。
Allthesekindsofprobabilityarereceiv’dbyphilosophers，andallow’dtobereasonablefoundationsofbeliefandopinion。Butthereareothers，thatarederiv’dfromthesameprinciples，tho’theyhavenothadthegoodfortunetoobtainthesamesanction。Thefirstprobabilityofthiskindmaybeaccountedforthus。Thediminutionoftheunion，andoftheresemblance，asaboveexplained，diminishesthefacilityofthetransition，andbythatmeansweakenstheevidence；andwemayfartherobserve，thatthesamediminutionoftheevidencewillfollowfromadiminutionoftheimpression，andfromtheshadingofthosecolours，underwhichitappearstothememoryorsenses。Theargument，whichwefoundonanymatteroffactweremember，ismoreorlessconvincingaccordingasthefactisrecentorremote；andtho’thedifferenceinthesedegreesofevidencebenotreceiv’dbyphilosophyassolidandlegitimate；becauseinthatcaseanargumentmusthaveadifferentforcetoday，fromwhatitshallhaveamonthhence；yetnotwithstandingtheoppositionofphilosophy，’tiscertain，thiscircumstancehasaconsiderableinfluenceontheunderstanding，andsecretlychangestheauthorityofthesameargument，accordingtothedifferenttimes，inwhichitispropos’dtous。Agreaterforceandvivacityintheimpressionnaturallyconveysagreatertotherelatedidea；and’tisonthedegreesofforceandvivacity，thatthebeliefdepends，accordingtotheforegoingsystem。
Thereisaseconddifference，whichwemayfrequentlyobserveinourdegreesofbeliefandassurance，andwhichneverfailstotakeplace，tho’disclaimedbyphilosophers。Anexperiment，thatisrecentandfreshinthememory，affectsusmorethanonethatisinsomemeasureobliterated；andhasasuperiorinfluenceonthejudgment，aswellasonthepassions。Alivelyimpressionproducesmoreassurancethanafaintone；becauseithasmoreoriginalforcetocommunicatetotherelatedidea，whichtherebyacquiresagreaterforceandvivacity。Arecentobservationhasalikeeffect；becausethecustomandtransitionistheremoreentire，andpreservesbettertheoriginalforceinthecommunication。Thusadrunkard，whohasseenhiscompaniondieofadebauch，isstruckwiththatinstanceforsometime，anddreadsalikeaccidentforhimself:Butasthememoryofitdecaysawaybydegrees，hisformersecurityreturns，andthedangerseemslesscertainandreal。
Iadd，asathirdinstanceofthiskind，thattho’ourreasoningsfromproofsandfromprobabilitiesbeconsiderablydifferentfromeachother，yettheformerspeciesofreasoningoftendegeneratesinsensiblyintothelatter，bynothingbutthemultitudeofconnectedarguments。’Tiscertain，thatwhenaninferenceisdrawnimmediatelyfromanobject，withoutanyintermediatecauseoreffect，theconvictionismuchstronger，andthepersuasionmorelively，thanwhentheimaginationiscarry’dthro’alongchainofconnectedarguments，howeverinfallibletheconnexionofeachlinkmaybeesteem’d。’Tisfromtheoriginalimpression，thatthevivacityofalltheideasisderiv’d，bymeansofthecustomarytransitionoftheimagination；and’tisevidentthisvivacitymustgraduallydecayinproportiontothedistance，andmustlosesomewhatineachtransition。Sometimesthisdistancehasagreaterinfluencethanevencontraryexperimentswou’dhave；andamanmayreceiveamorelivelyconvictionfromaprobablereasoning，whichiscloseandimmediate，thanfromalongchainofconsequences，tho’justandconclusiveineachpart。Nay’tisseldomsuchreasoningsproduceanyconviction；andonemusthaveaverystrongandfirmimaginationtopreservetheevidencetotheend，whereitpassesthro’somany，stages。
Buthereitmaynotbeamisstoremarkaverycuriousphaenomenon，whichthepresentsubjectsuggeststous。’Tisevidentthereisnopointofancienthistory，ofwhichwecanhaveanyassurance，butbypassingthro’manymillionsofcausesandeffects，andthro’achainofargumentsofalmostanimmeasurablelength。Beforetheknowledgeofthefactcou’dcometothefirsthistorian，itmustbeconvey’dthro’manymouths；andafteritiscommittedtowriting，eachnewcopyisanewobject，ofwhichtheconnexionwiththeforegoingisknownonlybyexperienceandobservation。Perhaps，therefore，itmaybeconcludedfromtheprecedentreasoning，thattheevidenceofallancienthistorymustnowbelost；oratleast，willbelostintime，asthechainofcausesencreases，andrunsontoagreaterlength。Butasitseemscontrarytocommonsensetothink，thatiftherepublicofletters，andtheartofprintingcontinueonthesamefootingasatpresent，ourposterity，evenafterathousandages，caneverdoubtiftherehasbeensuchamanasJULIUSCAESAR；thismaybeconsideredasanobjectiontothepresentsystem。Ifbeliefconsistedonlyinacertainvivacity，convey’dfromanoriginalimpression，itwou’ddecaybythelengthofthetransition，andmustatLastbeutterlyextinguished:Andviceversa，ifbeliefonsomeoccasionsbenotcapableofsuchanextinction；itmustbesomethingdifferentfromthatvivacity。
BeforeIanswerthisobjectionIshallobserve，thatfromthistopictherehasbeenborrow’daverycelebratedargumentagainsttheChristianReligion；’butwiththisdifference，thattheconnexionbetwixteachlinkofthechaininhumantestimonyhasbeentheresuppos’dnottogobeyondprobability，andtobeliabletoadegreeofdoubtanduncertainty。Andindeeditmustbeconfest，thatinthismannerofconsideringthesubject，(whichhoweverisnotatrueone)thereisnohistoryortradition，butwhatmustintheendloseallitsforceandevidence。Everynewprobabilitydiminishestheoriginalconviction；andhowevergreatthatconvictionmaybesuppos’d，’tisimpossibleitcansubsistundersuchre-iterateddiminutions。Thisistrueingeneral；tho’weshallfind(22)afterwards，thatthereisoneverymemorableexception，whichisofvastconsequenceinthepresentsubjectoftheunderstanding。
Meanwhiletogiveasolutionoftheprecedingobjectionuponthesupposition，thathistoricalevidenceamountsatfirsttoanentireproof；letusconsider，thattho’thelinksareinnumerable，thatconnectanyoriginalfactwiththepresentimpression，whichisthefoundationofbelief；yettheyareallofthesamekind，anddependonthefidelityofPrintersandCopyists。Oneeditionpassesintoanother，andthatintoathird，andsoon，tillwecometothatvolumeweperuseatpresent。Thereisnovariationinthesteps。Afterweknowoneweknowallofthem；andafterwehavemadeone，wecanhavenoscrupleastotherest。Thiscircumstancealonepreservestheevidenceofhistory，andwillperpetuatethememoryofthepresentagetothelatestposterity。Ifallthelongchainofcausesandeffects，whichconnectanypasteventwithanyvolumeofhistory，werecompos’dofpartsdifferentfromeachother，andwhich’twerenecessaryfortheminddistinctlytoconceive，’tisimpossibleweshou’dpreservetotheendanybelieforevidence。Butasmostoftheseproofsareperfectlyresembling，themindrunseasilyalongthem，jumpsfromoneparttoanotherwithfacility，andformsbutaconfus’dandgeneralnotionofeachlink。Bythismeansalongchainofargument，hasaslittleeffectindiminishingtheoriginalvivacity，。asamuchshorterwou’dhave，ifcompos’dofparts，whichweredifferentfromeachother，andofwhicheachrequir’dadistinctconsideration。
Afourthunphilosophicalspeciesofprobabilityisthatderiv’dfromgeneralrules，whichwerashlyformtoourselves，andwhicharethesourceofwhatweproperlycallPREJUDICE。AnIrishmancannothavewit，andaFrenchmancannothavesolidity；forwhichreason，tho’theconversationoftheformerinanyinstancebevisiblyveryagreeable，andofthelatterveryjudicious，wehaveentertainedsuchaprejudiceagainstthem，thattheymustbeduncesorfopsinspiteofsenseandreason。Humannatureisverysubjecttoerrorsofthiskind；andperhapsthisnationasmuchasanyother。
Shou’ditbedemandedwhymenformgeneralrules，andallowthemtoinfluencetheirjudgment，evencontrarytopresentobservationandexperience，Ishou’dreply，thatinmyopinionitproceedsfromthoseveryprinciples，onwhichalljudgmentsconcerningcausesandeffectsdepend。Ourjudgmentsconcerningcauseandeffectarederiv’dfromhabitandexperience；andwhenwehavebeenaccustomedtoseeoneobjectunitedtoanother，ourimaginationpassesfromthefirsttothesecond，byanaturaltransition，whichprecedesreflection，andwhichcannotbepreventedbyit。Now’tisthenatureofcustomnotonlytooperatewithitsfullforce，whenobjectsarepresented，thatareexactlythe，samewiththosetowhichwehavebeenaccustom’d；。butalsotooperateinaninferiordegree，whenwediscoversuchasaresimilar；andtho’thehabitlosessomewhatofitsforcebyeverydifference，yet’tisseldomentirelydestroy’d，whereanyconsiderablecircumstancesremainthesame。Aman，whohascontractedacustomofeatingfruitbytheuseofpearsorpeaches，willsatisfyhimselfwithmelons，wherehecannotfindhisfavouritefruit；asone，whohasbecomeadrunkardbytheuseofredwines，willbecarriedalmostwiththesameviolencetowhite，ifpresentedtohim。FromthisprincipleIhaveaccountedforthatspeciesofprobability，deriv’dfromanalogy，wherewetransferourexperienceinpastinstancestoobjectswhichareresembling，butarenotexactlythesamewiththoseconcerningwhichwehavehadexperience。Inproportionastheresemblancedecays，theprobabilitydiminishes；butstillhassomeforceaslongasthereremainanytracesoftheresemblance。
Thisobservationwemaycarryfarther；andmayremark，thattho’custombethefoundationofallourjudgments，yetsometimesithasaneffectontheimaginationinoppositiontothejudgment，andproducesacontrarietyinoursentimentsconcerningthesameobject。Iexplainmyself。Inalmostallkindsofcausesthereisacomplicationofcircumstances，ofwhichsomeareessential，andotherssuperfluous；someareabsolutelyrequisitetotheproductionoftheeffect，andothersareonlyconjoin’dbyaccident。Nowwemayobserve，thatwhenthesesuperfluouscircumstancesarenumerous，andremarkable，andfrequentlyconjoin’dwiththeessential，theyhavesuchaninfluenceontheimagination，thatevenintheabsenceofthelattertheycarryusontot-heconceptionoftheusualeffect，andgivetothatconceptionaforceandvivacity，whichmakeitsuperiortothemerefictionsofthefancy。Wemaycorrectthispropensitybyareflectiononthenatureofthosecircumstances:but’tisstillcertain，thatcustomtakesthestart，andgivesabiasstotheimagination。
Toillustratethisbyafamiliarinstance，letusconsiderthecaseofaman，who，beinghungoutfromahightowerinacageofironcannotforbeartrembling，whenhesurveystheprecipicebelowhim，tho’heknowshimselftobeperfectlysecurefromfalling，byhisexperienceofthesolidityoftheiron，whichsupportshim；andtho’theideasoffallanddescent，andharmanddeath，bederiv’dsolelyfromcustomandexperience。Thesamecustomgoesbeyondtheinstances，fromwhichitisderiv’d，andtowhichitperfectlycorresponds；andinfluenceshisideasofsuchobjectsasareinsomerespectresembling，butfallnotpreciselyunderthesamerule。Thecircumstancesofdepthanddescentstrikesostronglyuponhim，thattheirinfluencecan-notbedestroy’dbythecontrarycircumstancesofsupportandsolidity，whichoughttogivehimaperfectsecurity。Hisimaginationrunsawaywithitsobject，andexcitesapassionproportion’dtoit。Thatpassionreturnsbackupontheimaginationandinlivenstheidea；whichlivelyideahasanewinfluenceonthepassion，andinitsturnaugmentsitsforceandviolence；andbothhisfancyandaffections，thusmutuallysupportingeachother，causethewholetohaveaverygreatinfluenceuponhim。
Butwhyneedweseekforotherinstances，whilethepresentsubjectofphilosophicalprobabilitiesoffersussoobviousanone，intheoppositionbetwixtthejudgmentandimaginationarisingfromtheseeffectsofcustom？Accordingtomysystem，allreasoningsarenothingbuttheeffectsofcustom；andcustomhasnoinfluence，butbyinliveningtheimagination，andgivingusastrongconceptionofanyobject。Itmay，therefore，beconcluded，thatourjudgmentandimaginationcanneverbecontrary，andthatcustomcannotoperateonthelatterfacultyaftersuchamanner，astorenderitoppositetotheformer。Thisdifficultywecanremoveafternoothermanner，thanbysupposingtheinfluenceofgeneralrules。Weshallafterwardstake(23)noticeofsomegeneralrules，bywhichweoughttoregulateourjudgmentconcerningcausesandeffects；andtheserulesareform’donthenatureofourunderstanding，andonourexperienceofitsoperationsinthejudgmentsweformconcerningobjects。Bythemwelearntodistinguishtheaccidentalcircumstancesfromtheefficaciouscauses；andwhenwefindthataneffectcanbeproduc’dwithouttheconcurrenceofanyparticularcircumstance，weconcludethatthatcircumstancemakesnotapartoftheefficaciouscause，howeverfrequentlyconjoin’dwithit。Butasthisfrequentconjunctionnecessitymakesithavesomeeffectontheimagination，inspiteoftheoppositeconclusionfromgeneralrules，theoppositionofthesetwoprinciplesproducesacontrarietyinourthoughts，andcausesustoascribetheoneinferencetoourjudgment，andtheothertoourimagination。Thegeneralruleisattributedtoourjudgment；asbeingmoreextensiveandconstant。Theexceptiontotheimagination，asbeingmorecapriciousanduncertain。
Thusourgeneralrulesareinamannersetinoppositiontoeachother。Whenanobjectappears，thatresemblesanycauseinveryconsiderablecircumstances，theimaginationnaturallycarriesustoalivelyconceptionoftheusualeffect，Tho’theobjectbedifferentinthemostmaterialandmostefficaciouscircumstancesfromthatcause。Hereisthefirstinfluenceofgeneralrules。Butwhenwetakeareviewofthisactofthemind，andcompareitwiththemoregeneralandauthenticoperationsoftheunderstanding，wefindittobeofanirregularnature，anddestructiveofallthemostestablishedprinciplesofreasonings；whichisthecauseofourrejectingit。Thisisasecondinfluenceofgeneralrules，andimpliesthecondemnationoftheformer。Sometimestheone，sometimestheotherprevails，accordingtothedispositionandcharacteroftheperson。Thevulgararecommonlyguidedbythefirst，andwisemenbythesecond。Meanwhilethescepticsmayherehavethepleasureofobservinganewandsignalcontradictioninourreason，andofseeingallphilosophyreadytobesubvertedbyaprincipleofhumannature，andagainsav’dbyanewdirectionoftheverysameprinciple。Thefollowingofgeneralrulesisaveryunphilosophicalspeciesofprobability；andyet’tisonlybyfollowingthemthatwecancorrectthis，andallotherunphilosophicalprobabilities。
Sincewehaveinstances，wheregeneralrulesoperateontheimaginationevencontrarytothejudgment，weneednotbesurpriz’dtoseetheireffectsencrease，whenconjoin’dwiththatlatterfaculty，andtoobservethattheybestowontheideastheypresenttousaforcesuperiortowhatattendsanyother。Everyoneknows，thereisanindirectmannerofinsinuatingpraiseorblame，whichismuchlessshockingthantheopenflatteryorcensureofanyperson。Howeverbemaycommunicatehissentimentsbysuchsecretinsinuations，andmakethemknownwithequalcertaintyasbytheopendiscoveryofthem，’tiscertainthattheirinfluenceisnotequallystrongandpowerful。Onewholashesmewithconceal’dstrokesofsatire，movesnotmyindignationtosuchadegree，asifheflatlytoldmeIwasafoolandcoxcomb；tho’Iequallyunderstandhismeaning，asifhedid。Thisdifferenceistobeattributedtotheinfluenceofgeneralrules。
Whetherapersonopenly，abusesme，orslylyintimateshiscontempt，inneithercasedoIimmediatelyperceivehissentimentoropinion；and’tisonlybysigns，thatis，byitseffects，Ibecomesensibleofit。Theonlydifference，then，betwixtthesetwocasesconsistsinthis，thatintheopendiscoveryofhissentimentshemakesuseofsigns，whicharegeneralanduniversal；andinthesecretintimationemployssuchasaremoresingularanduncommon。Theeffectofthiscircumstanceis，thattheimagination，inrunningfromthepresentimpressiontotheabsentidea，makesthetransitionwithgreaterfacility，andconsequentlyconceivestheobjectwithgreaterforce，wheretheconnexioniscommonanduniversal，thanwhereitismorerareandparticular。Accordinglywemayobserve，thattheopendeclarationofoursentimentsiscall’dthetakingoffthemask，asthesecretintimationofouropinionsissaidtobetheveilingofthem。Thedifferencebetwixtanideaproduc’dbyageneralconnexion，andthatarisingfromaparticularoneisherecompar’dtothedifferencebetwixtanimpressionandanidea。Thisdifferenceintheimaginationhasasuitableeffectonthepassions；andthiseffectisaugmentedbyanothercircumstance。Asecretintimationofangerorcontemptshewsthatwestillhavesomeconsiderationfortheperson，andavoidthedirectlyabusinghim。Thismakesaconceal’dsatirelessdisagreeable；butstillthisdependsonthesameprinciple。Forifanideawerenotmorefeeble，whenonlyintimated，itwou’dneverbeesteem’damarkofgreaterrespecttoproceedinthismethodthanintheother。
Sometimesscurrilityislessdispleasingthandelicatesatire，becauseitrevengesusinamannerfortheinjuryattheverytimeitiscommitted，byaffordingusajustreasontoblameandcontemntheperson，whoinjuresus。Butthisphaenomenonlikewisedependsuponthesameprinciple。Forwhydoweblameallgrossandinjuriouslanguage，unlessitbe，becauseweesteemitcontrarytogoodbreedingandhumanity？Andwhyisitcontrary，unlessitbemoreshockingthananydelicatesatire？Therulesofgoodbreedingcondemnwhateverisopenlydisobliging，andgivesasensiblepainandconfusiontothose，withwhomweconverse。Afterthisisonceestablished，abusivelanguageisuniversallyblam’d，andgiveslesspainuponaccountofitscoarsenessandincivility，whichrenderthepersondespicable，thatemploysit。Itbecomeslessdisagreeable，merelybecauseoriginallyitismoreso；and’tismoredisagreeable，becauseitaffordsaninferencebygeneralandcommonrules，thatarepalpableandundeniable。
Tothisexplicationofthedifferentinfluenceofopenandconceal’dflatteryorsatire，Ishalladdtheconsiderationofanotherphenomenon，whichisanalogoustoit。Therearemanyparticularsinthepointofhonourbothofmenandwomen，whoseviolations，whenopenandavow’d，theworldneverexcuses，butwhichitismoreapttooverlook，whentheappearancesaresav’d，andthetransgressionissecretandconceal’d。Eventhose，whoknowwithequalcertainty，thatthefaultiscommitted，pardonitmoreeasily，whentheproofsseeminsomemeasureobliqueandequivocal，thanwhentheyaredirectandundeniable。Thesameideaispresentedinbothcases，and，properlyspeaking，isequallyassentedtobythejudgment；andyetitsinfluenceisdifferent，becauseofthedifferentmanner，inwhichitispresented。
Nowifwecomparethesetwocases，oftheopenandconceal’dviolationsofthelawsofhonour，weshallfind，thatthedifferencebetwixtthemconsistsinthis，thatinthefirsteasethesign，fromwhichweinfertheblameableaction，issingle，andsufficesalonetobethefoundationofourreasoningandjudgment；whereasinthelatterthesignsarenumerous，anddecidelittleornothingwhenaloneandunaccompany’dwithmanyminutecircumstances，whicharealmostimperceptible。But’tiscertainlytrue，thatanyreasoningisalwaysthemoreconvincing，themoresingleanduniteditistotheeye，andthelessexerciseitgivestotheimaginationtocollectallitsparts，andrunfromthemtothecorrelativeidea，whichformstheconclusion。Thelabourofthethoughtdisturbstheregularprogressofthesentiments，asweshallobservepresently。(24)Theideastrikesnotonuswithouchvivacity；andconsequentlyhasnosuchinfluenceonthepassionandimagination。
FromthesameprincipleswemayaccountforthoseobservationsoftheCARDINALDERETZ，thattherearemanythings，inwhichtheworldwishestobedeceiv’d；andthatitmoreeasilyexcusesapersoninactingthanintalkingcontrarytothedecorumofhisprofessionandcharacter。Afaultinwordsiscommonlymoreopenanddistinctthanoneinactions，whichadmitofmanypalliatingexcuses，anddecidenotsoclearlyconcerningtheintentionandviewsoftheactor。
Thusitappearsuponthewhole，thateverykindofopinionorjudgment，whichamountsnottoknowledge，isderiv’dentirelyfromtheforceandvivacityoftheperception，andthatthesequalitiesconstituteinthemind，whatwecalltheBELIEFOftheexistenceofanyobject。Thisforceandthisvivacityaremostconspicuousinthememory；andthereforeourconfidenceintheveracityofthatfacultyisthegreatestimaginable，andequalsinmanyrespectstheassuranceofademonstration。Thenextdegreeofthesequalitiesisthatderiv’dfromtherelationofcauseandeffect；andthistooisverygreat，especiallywhentheconjunctionisfoundbyexperiencetobeperfectlyconstant，andwhentheobject，whichispresenttous，exactlyresemblesthose，ofwhichwehavehadexperience。Butbelowthisdegreeofevidencetherearemanyothers，whichhaveaninfluenceonthepassionsandimagination，proportionedtothatdegreeofforceandvivacity，whichtheycommunicatetotheideas。’Tisbyhabitwemakethetransitionfromcausetoeffect；and’tisfromsomepresentimpressionweborrowthatvivacity，whichwediffuseoverthecorrelativeidea。Butwhenwehavenotobserv’dasufficientnumberofinstances，toproduceastronghabit；orwhentheseinstancesarecontrarytoeachother；orwhentheresemblanceisnotexact；orthepresentimpressionisfaintandobscure；ortheexperienceinsomemeasureobliteratedfromthememory；ortheconnexiondependentonalongchainofobjects；ortheinferencederiv’dfromgeneralrules，andyetnotconformabletothem:Inallthesecasestheevidencediminishesbythediminutionoftheforceandintensenessoftheidea。Thisthereforeisthenatureofthejudgmentandprobability。，Whatprincipallygivesauthoritytothissystemis，besidetheundoubtedarguments，uponwhicheachpartisfounded，theagreementoftheseparts，andthenecessityofonetoexplainanother。Thebelief，whichattendsourmemory，isofthesamenaturewiththat，whichisderiv’dfromourjudgments:Noristhereanydifferencebetwixtthatjudgment，whichisderiv’dfromaconstantanduniformconnexionofcausesandeffects，andthatwhichdependsuponaninterruptedanduncertain。’Tisindeedevident，thatinalldeterminations，wheretheminddecidesfromcontraryexperiments，’tisfirstdividedwithinitself，andhasaninclinationtoeithersideinproportiontothenumberofexperimentswehaveseenandremember。Thiscontestisatlastdetermin’dtotheadvantageofthatside，whereweobserveasuperiornumberoftheseexperiments；butstillwithadiminutionofforceintheevidencecorrespondenttothenumberoftheoppositeexperiments。Eachpossibility，ofwhichtheprobabilityiscompos’d，operatesseparatelyupontheimagination；and’tisthelargercollectionofpossibilities，whichatlastprevails，andthatwithaforceproportionabletoitssuperiority。Allthesephenomenaleaddirectlytotheprecedentsystem；norwilliteverbepossibleuponanyotherprinciplestogiveasatisfactoryandconsistentexplicationofthem。Withoutconsideringthesejudgmentsastheeffectsofcustomontheimagination，weshallloseourselvesinperpetualcontradictionandabsurdity。
OftheIdeaofNecessaryConnexion。
Havingthusexplain’dthemanner，inwhichwereasonbeyondourimmediateimpressions，andconcludethatsuchparticularcausesmusthavesuchparticulareffects；wemustnowreturnuponourfootstepstoexaminethatquestion，which(25)firstoccur’dtous，andwhichwedroptinourway，viz。Whatisourideaofnecessity，whenwesaythattwoobjectsarenecessarilyconnectedtogether。UponthisheadIrepeatwhatIhaveoftenhadoccasiontoobserve，thataswehavenoidea，thatisnotderiv’dfromanimpression，wemustfindsomeimpression，thatgivesrisetothisideaofnecessity，ifweassertwehavereallysuchanidea。InordertothisIconsider，inwhatobjectsnecessityiscommonlysuppos’dtolie；andfindingthatitisalwaysascrib’dtocausesandeffects，Iturnmyeyetotwoobjectssuppos’dtobeplac’dinthatrelation；andexaminetheminallthesituations，ofwhichtheyaresusceptible。Iimmediatelyperceive，thattheyarecontiguousintimeandplace，andthattheobjectwe-callcauseprecedestheotherwecalleffect。InnooneinstancecanIgoanyfarther，norisitpossibleformetodiscoveranythirdrelationbetwixttheseobjects。Ithereforeenlargemyviewtocomprehendseveralinstances；whereIfindlikeobjectsalwaysexistinginlikerelationsofcontiguityandsuccession。Atfirstsightthisseemstoservebutlittletomypurpose。Thereflectiononseveralinstancesonlyrepeatsthesameobjects；andthereforecannevergiverisetoanewidea。ButuponfartherenquiryIfind，thattherepetitionisnotineveryparticularthesame，butproducesanewimpression，andbythatmeanstheidea，whichIatpresentexamine。Forafterafrequentrepetition，Ifind，thatupontheappearanceofoneoftheobjects，themindisdetermin’dbycustomtoconsideritsusualattendant，andtoconsideritinastrongerlightuponaccountofitsrelationtothefirstobject。’Tisthisimpression，then，ordetermination，whichaffordsmetheideaofnecessity。
Idoubtnotbuttheseconsequenceswillatfirstsightbereceiv’dwithoutdifficulty，asbeingevidentdeductionsfromprinciples，whichwehavealreadyestablished，andwhichwehaveoftenemploy’dinourreasonings。Thisevidencebothinthefirstprinciples，andinthedeductions，mayseduceusunwarilyintotheconclusion，andmakeusimagineitcontainsnothingextraordinary，norworthyofourcuriosity。Buttho’suchaninadvertencemayfacilitatethereceptionofthisreasoning，’twillmakeitbethemoreeasilyforgot；forwhichreasonIthinkitpropertogivewarning，thatIhavejustnowexamin’doneofthemostsublimequestionsinphilosophy，viz。thatconcerningthepowerandefficacyofcauses；whereallthesciencesseemsomuchinterested。Suchawarningwillnaturallyrouzeuptheattentionofthereader，andmakehimdesireamorefullaccountofmydoctrine，aswellasofthearguments，onwhichitisfounded。Thisrequestissoreasonable，thatIcannotrefusecomplyingwithit；especiallyasIamhopefulthattheseprinciples，themoretheyareexamin’d，willacquirethemoreforceandevidence。
Thereisnoquestion，whichonaccountofitsimportance，aswellasdifficulty，hascaus’dmoredisputesbothamongantientandmodernphilosophers，thanthisconcerningtheefficacyofcauses，orthatqualitywhichmakesthembefollow’dbytheireffects。Butbeforetheyenter’duponthesedisputes，methinksitwou’dnothavebeenimpropertohaveexamin’dwhatideawehaveofthatefficacy，whichisthesubjectofthecontroversy。ThisiswhatIfindprincipallywantingintheirreasonings，andwhatIshallhereendeavourtosupply。
Ibeginwithobservingthatthetermsofefficacy，agency，power，force，energy，necessity，connexion，andproductivequality，areallnearlysynonymous；andtherefore’tisanabsurditytoemployanyofthemindefiningtherest。Bythisobservationwerejectatonceallthevulgardefinitions，whichphilosophershavegivenofpowerandefficacy；andinsteadofsearchingfortheideainthesedefinitions，mustlookforitintheimpressions，fromwhichitisoriginallyderiv’d。Ifitbeacompoundidea，itmustarisefromcompoundimpressions。Ifsimple，fromsimpleimpressions。
Ibelievethemostgeneralandmostpopularexplicationofthismatter，istosay，(26)thatfindingfromexperience，thatthereareseveralnewproductionsinmatter，suchasthemotionsandvariationsofbody，andconcludingthattheremustsomewherebeapowercapableofproducingthem，wearriveatlastbythisreasoningattheideaofpowerandefficacy。Buttobeconvinc’dthatthisexplicationismorepopularthanphilosophical，weneedbutreflectontwoveryobviousprinciples。First，Thatreasonalonecannevergiverisetoanyoriginalidea，andsecondly，thatreason，asdistinguish’dfromexperience，cannevermakeusconclude，thatacauseorproductivequalityisabsolutelyrequisitetoeverybeginningofexistence。Boththeseconsiderationshavebeensufficientlyexplain’d:andthereforeshallnotatpresentbeanyfartherinsistedon。
Ishallonlyinferfromthem，thatsincereasoncannevergiverisetotheideaofefficacy，thatideamustbederiv’dfromexperience，andfromsomeparticularinstancesofthisefficacy，whichmaketheirpassageintothemindbythecommonchannelsofsensationorreflection。Ideasalwaysrepresenttheirobjectsorimpressions；andviceversa，therearesomeobjectsnecessarytogiverisetoeveryidea。Ifwepretend，therefore，tohaveanyjustideaofthisefficacy，wemustproducesomeinstance，whereintheefficacyisplainlydiscoverabletothemind，anditsoperationsobvioustoourconsciousnessorsensation。Bytherefusalofthis，weacknowledge，thattheideaisimpossibleandimaginary，sincetheprincipleofinnateideas，whichalonecansaveusfromthisdilemma，hasbeenalreadyrefuted，andisnowalmostuniversallyrejectedinthelearnedworld。Ourpresentbusiness，then，mustbetofindsomenaturalproduction，wheretheoperationandefficacyofacausecanbeclearlyconceiv’dandcomprehendedbythemind，withoutanydangerofobscurityormistake。
Inthisresearchwemeetwithverylittleencouragementfromthatprodigiousdiversity，whichisfoundintheopinionsofthosephilosophers，whohavepretendedtoexplainthesecretforceandenergyofcauses。(27)Therearesome，whomaintain，thatbodiesoperatebytheirsubstantialform；others，bytheiraccidentsorqualities；several，bytheirmatterandform；some，bytheirformandaccidents；others，bycertainvirtuesandfacultiesdistinctfromallthis。Allthesesentimentsagainaremix’dandvary’dinathousanddifferentways；andformastrongpresumption，thatnoneofthemhaveanysolidityorevidence，，andthatthesuppositionofanefficacyinanyoftheknownqualitiesofmatterisentirelywithoutfoundation。Thispresumptionmustencreaseuponus，whenweconsider，thattheseprinciplesofsubstantialforms，andaccidents，andfaculties，arenotinrealityanyoftheknownpropertiesofbodies，butareperfectlyunintelligibleandinexplicable。For’tisevidentphilosopherswou’dneverhavehadrecoursetosuchobscureanduncertainprinciples，hadtheymetwithanysatisfactioninsuchasareclearandintelligible；especiallyinsuchanaffairasthis，whichmustbeanobjectofthesimplestunderstanding，ifnotofthesenses。Uponthewhole，wemayconclude，that’tisimpossibleinanyoneinstancetoshewtheprinciple，inwhichtheforceandagencyofacauseisplac’d；andthatthemostrefin’dandmostvulgarunderstandingsareequallyatalossinthisparticular。Ifanyonethinkpropertorefutethisassertion，heneednotputhimselftothetroubleofinventinganylongreasonings:butmayatonceshewusaninstanceofacause，wherewediscoverthepoweroroperatingprinciple。Thisdefianceweareoblig’dfrequentlytomakeuseof，asbeingalmosttheonlymeansofprovinganegativeinphilosophy。
Thesmallsuccess，whichhasbeenmetwithinalltheattemptstofixthispower，hasatlastoblig’dphilosopherstoconclude，thattheultimateforceandefficacyofnatureisperfectlyunknowntous，andthat’tisinvainwesearchforitinalltheknownqualitiesofmatter。Inthisopiniontheyarealmostunanimous；and’tisonlyintheinferencetheydrawfromit，thattheydiscoveranydifferenceintheirsentiments。Forsomeofthem，astheCartesiansinparticular，havingestablisheditasaprinciple，thatweareperfectlyacquaintedwiththeessenceofmatter，haveverynaturallyinferr’d，thatitisendow’dwithnoefficacy，andthat’tisimpossibleforitofitselftocommunicatemotion，orproduceanyofthoseeffects，whichweascribetoit。Astheessenceofmatterconsistsinextension，andasextensionimpliesnotactualmotion，butonlymobility；theyconclude，thattheenergy，whichproducesthemotion，cannotlieintheextension。
Thisconclusionleadsthemintoanother，whichtheyregardasperfectlyunavoidable。Matter，saythey，isinitselfentirelyunactive，anddepriv’dofanypower，bywhichitmayproduce，orcontinue，orcommunicatemotion:Butsincetheseeffectsareevidenttooursenses，andsincethepower，thatproducesthem，mustbeplac’dsomewhere，itmustlieintheDEITY，orthatdivinebeing，whocontainsinhisnatureallexcellencyandperfection。’Tisthedeity，therefore，whoistheprimemoveroftheuniverse，andwhonotonlyfirstcreatedmatter，andgaveitit’soriginalimpulse，butlikewisebyacontinu’dexertionofomnipotence，supportsitsexistence，andsuccessivelybestowsonitallthosemotions，andconfigurations，andqualities，withwhichitisendow’d。
Thisopinioniscertainlyverycurious，andwellworthourattention；but’twillappearsuperfluoustoexamineitinthisplace，ifwereflectamomentonourpresentpurposeintakingnoticeofit。Wehaveestablisheditasaprinciple，thatasallideasarederiv’dfromimpressions，orsomeprecedentperceptions，’tisimpossiblewecanhaveanyideaofpowerandefficacy，unlesssomeinstancescanbeproduc’d，whereinthispowerisperceiv’dtoexertitself。Now，astheseinstancescanneverbediscoveredinbody，theCartesians，proceedingupontheirprincipleofinnateideas，havehadrecoursetoasupremespiritordeity，whomtheyconsiderastheonlyactivebeingintheuniverse，andastheimmediatecauseofeveryalterationinmatter。Buttheprincipleofinnateideasbeingallow’dtobefalse，itfollows，thatthesuppositionofadeitycanserveusinnostead，inaccountingforthatideaofagency，whichwesearchforinvaininalltheobjects，whicharepresentedtooursenses，orwhichweareinternallyconsciousofinourownminds。Forifeveryideabederiv’dfromanimpression，theideaofadeityproceedsfromthesameorigin；andifnoimpression，eitherofsensationorreflection，impliesanyforceorefficacy，’tisequallyimpossibletodiscoverorevenimagineanysuchactiveprincipleinthedeity。Sincethesephilosophers，therefore，haveconcluded，thatmattercannotbeendow’dwithanyefficaciousprinciple，because’tisimpossibletodiscoverinitsuchaprinciple；thesamecourseofreasoningshou’ddeterminethemtoexcludeitfromthesupremebeing。Oriftheyesteemthatopinionabsurdandimpious，asitreallyis，Ishalltellthemhowtheymayavoidit；andthatis，byconcludingfromtheveryfirst，thattheyhavenoadequateideaofpowerorefficacyinanyobject；sinceneitherinbodynorspirit，neitherinsuperiornorinferiornatures，aretheyabletodiscoveronesingleinstanceofit。
Thesameconclusionisunavoidableuponthehypothesisofthose，whomaintaintheefficacyofsecondcauses，andattributeaderivative，butarealpowerandenergytomatter。Forastheyconfess，thatthisenergyliesnotinanyoftheknownqualitiesofmatter，thedifficultystillremainsconcerningtheoriginofitsidea。Ifwehavereallyanideaofpower，wemayattributepowertoanunknownquality:Butas’tisimpossible，thatthatideacanbederiv’dfromsuchaquality，andasthereisnothinginknownqualities，whichcanproduceit；itfollowsthatwedeceiveourselves，whenweimaginewearepossestofanyideaofthiskind，afterthemannerwecommonlyunderstandit。Allideasarederiv’dfrom，andrepresentimpressions。Weneverhaveanyimpression，thatcontainsanypowerorefficacy。Weneverthereforehaveanyideaofpower。
[Thisparagraphisinsertedfromtheappendix。]
Somehaveasserted，thatwefeelanenergy，orpower，inourownmind；andthathavinginthismanneracquir’dtheideaofpower，wetransferthatqualitytomatter，wherewearenotableimmediatelytodiscoverit。Themotionsofourbody，andthethoughtsandsentimentsofourmind，(saythey)obeythewill；nordoweseekanyfarthertoacquireajustnotionofforceorpower。Buttoconvinceushowfallaciousthisreasoningis，weneedonlyconsider，thatthewillbeinghereconsider’dasacause，hasnomoreadiscoverableconnexionwithitseffects，thananymaterialcausehaswithitspropereffect。Sofarfromperceivingtheconnexionbetwixtanactofvolition，andamotionofthebody；’tisallow’dthatnoeffectismoreinexplicablefromthepowersandessenceofthoughtandmatter。Noristheempireofthewilloverourmindmoreintelligible。Theeffectistheredistinguishableandseparablefromthecause，andcou’dnotbeforeseenwithouttheexperienceoftheirconstantconjunction。Wehavecommandoverourmindtoacertaindegree，butbeyondthat，loseallempireoverit:And’tisevidentlyimpossibletofixanypreciseboundstoourauthority，whereweconsultnotexperience。Inshort，theactionsofthemindare，inthisrespect，thesamewiththoseofmatter。Weperceiveonlytheirconstantconjunction；norcanweeverreasonbeyondit。Nointernalimpressionhasanapparentenergy，morethanexternalobjectshave。Since，therefore，matterisconfess’dbyphilosopherstooperatebyanunknownforce，weshou’dinvainhopetoattainanideaofforcebyconsultingourownminds。(28)
Ithasbeenestablishedasacertainprinciple，thatgeneralorabstractideasarenothingbutindividualonestakeninacertainlight，andthat，inreflectingonanyobject，’tisasimpossibletoexcludefromourthoughtallparticulardegreesofquantityandqualityasfromtherealnatureofthings。Ifwebepossest，therefore，ofanyideaofpoweringeneral，wemustalsobeabletoconceivesomeparticularspeciesofit；andaspowercannotsubsistalone，butisalwaysregardedasanattributeofsomebeingorexistence，wemustbeable。toplacethispowerinsomeparticularbeing，andconceivethatbeingasendow’dwitharealforceandenergy，bywhichsuchaparticulareffectnecessarilyresultsfromitsoperation。Wemustdistinctlyandparticularlyconceivetheconnexionbetwixtthecauseandeffect，andbeabletopronounce，fromasimpleviewoftheone，thatitmustbefollow’dorprecededbytheother。Thisisthetruemannerofconceivingaparticularpowerinaparticularbody:andageneralideabeingimpossiblewithoutanindividual；wherethelatterisimpossible，’tiscertaintheformercanneverexist。Nownothingismoreevident，thanthatthehumanmindcannotformsuchanideaoftwoobjects，astoconceiveanyconnexionbetwixtthem，orcomprehenddistinctlythatpowerorefficacy，bywhichtheyareunited。Suchaconnexionwou’damounttoademonstration，andwou’dimplytheabsoluteimpossibilityfortheoneobjectnottofollow，ortobeconceiv’dnottofollowupontheother:Whichkindofconnexionhasalreadybeenrejectedinallcases。Ifanyoneisofacontraryopinion，andthinkshehasattain’danotionofpowerinanyparticularobject，Idesirehemaypointouttomethatobject。ButtillImeetwithsuch-a-one，whichIdespairof，Icannotforbearconcluding，thatsincewecanneverdistinctlyconceivehowanyparticularpowercanpossiblyresideinanyparticularobject，wedeceiveourselvesinimaginingwecanformanysuchgeneralidea。
Thusuponthewholewemayinfer，thatwhenwetalkofanybeing，whetherofasuperiororinferiornature，asendow’dwithapowerorforce，proportionedtoanyeffect；whenwespeakofanecessaryconnexionbetwixtobjects，andsuppose，thatthisconnexiondependsuponanefficacyorenergy，withwhichanyoftheseobjectsareendow’d；inalltheseexpressions，soapply’d，wehavereallynodistinctmeaning，andmakeuseonlyofcommonwords，withoutanyclearanddeterminateideas。Butas’tismoreprobable，thattheseexpressionsdoherelosetheirtruemeaningbybeingwrongapply’d，thanthattheyneverhaveanymeaning；’twillbepropertobestowanotherconsiderationonthissubject，toseeifpossiblywecandiscoverthenatureandoriginofthoseideas，weannextothem。
Supposetwoobjectstobepresentedtous，ofwhichtheoneisthecauseandtheothertheeffect；’tisplain，thatfromthesimpleconsiderationofone，orboththeseobjectswenevershallperceivethetiebywhichtheyareunited，orbeablecertainlytopronounce，thatthereisaconnexionbetwixtthem。’Tisnot，therefore，fromanyoneinstance，thatwearriveattheideaofcauseandeffect，ofanecessaryconnexionofpower，offorce，ofenergy，andofefficacy。Didweneverseeanybutparticularconjunctionsofobjects，entirelydifferentfromeachother，weshou’dneverbeabletoformanysuchideas。
Butagain；supposeweobserveseveralinstances，inwhichthesameobjectsarealwaysconjoin’dtogether，weimmediatelyconceiveaconnexionbetwixtthem，andbegintodrawaninferencefromonetoanother。Thismultiplicityofresemblinginstances，therefore，constitutestheveryessenceofpowerorconnexion，andisthesourcefromwhichtheideaofitarises。Inorder，then，tounderstandtheideaofpower，wemustconsiderthatmultiplicity；nordoIaskmoretogiveasolutionofthatdifficulty，whichhassolongperplex’dus。ForthusIreason。Therepetitionofperfectlysimilarinstancescanneveralonegiverisetoanoriginalidea，differentfromwhatistobefoundinanyparticularinstance，ashasbeenobserv’d，andasevidentlyfollowsfromourfundamentalprinciple，thatallideasarecopy’dfromimpressions。Sincethereforetheideaofpowerisaneworiginalidea，nottobefoundinanyoneinstance，andwhichyetarisesfromtherepetitionofseveralinstances，itfollows，thattherepetitionalonehasnotthateffect，butmusteitherdiscoverorproducesomethingnew，whichisthesourceofthatidea。Didtherepetitionneitherdiscovernorproduceanythingnew，ourideasmightbemultiply’dbyit，butwou’dnotbeenlarg’dabovewhattheyareupontheobservationofonesingleinstance。Everyenlargement，therefore，(suchastheideaofpowerorconnexion)whicharisesfromthemultiplicityofsimilarinstances，iscopy’dfromsomeeffectsofthemultiplicity，andwillbeperfectlyunderstoodbyunderstandingtheseeffects。Whereverwefindanythingnewtobediscoveredorproduc’dbytherepetition，therewemustplacethepower，andmustneverlookforitinanyotherobject。
But’tisevident，inthefirstplace，thattherepetitionoflikeobjectsinlikerelationsofsuccessionandcontiguitydiscoversnothingnewinanyoneofthem:sincewecandrawnoinferencefromit，normakeitasubjecteitherofourdemonstrativeorprobablereasonings；(29)ashasbeenalreadyprov’d。Naysupposewecou’ddrawaninference，’twou’dbeofnoconsequenceinthepresentcase；sincenokindofreasoningcangiverisetoanewidea，suchasthisofpoweris；butwhereverwereason，wemustantecedentlybepossestofclearideas，whichmaybetheobjectsofourreasoning。Theconceptionalwaysprecedestheunderstanding；andwheretheoneisobscure，theotherisuncertain；wheretheonefails，theothermustfailalso。
Secondly，’Tiscertainthatthisrepetitionofsimilarobjectsinsimilarsituationsproducesnothingneweitherintheseobjects，orinanyexternalbody。For’twillreadilybeallow’d，thattheseveralinstanceswehaveoftheconjunctionofresemblingcausesandeffectsareinthemselvesentirelyindependent，andthatthecommunicationofmotion，whichIseeresultatpresentfromtheshockoftwobilliard-balls，istotallydistinctfromthatwhichIsawresultfromsuchanimpulseatwelve-monthago。Theseimpulseshavenoinfluenceoneachother。Theyareentirelydividedbytimeandplace；andtheonemighthaveexistedandcommunicatedmotion，tho’theotherneverhadbeeninbeing。
Thereis，then，nothingneweitherdiscoveredorproduc’dinanyobjectsbytheirconstantconjunction，andbytheuninterruptedresemblanceoftheirrelationsofsuccessionandcontiguity。But’tisfromthisresemblance，thattheideasofnecessity，ofpower，andofefficacy，arederiv’d。Theseideas，，therefore，representnotanything，thatdoesorcanbelongtotheobjects，whichareconstantlyconjoined。Thisisanargument，which，ineveryviewwecanexamineit，willbefoundperfectlyunanswerable。Similarinstancesarestillthefirstsourceofourideaofpowerornecessity；atthesametimethattheyhavenoinfluencebytheirsimilarityeitheroneachother，oronanyexternalobject。Wemust，therefore，turnourselvestosomeotherquartertoseektheoriginofthatidea。
Tho’theseveralresemblinginstances，whichgiverisetotheideaofpower，havenoinfluenceoneachother，andcanneverproduceanynewqualityintheobject，whichcanbethemodelofthatidea，yettheobservationofthisresemblanceproducesanewimpressioninthemind，whichisitsrealmodel。Forafterwehaveobserv’dtheresemblanceinasufficientnumberofinstances，weimmediatelyfeeladeterminationofthemindtopassfromoneobjecttoitsusualattendant，andtoconceiveitinastrongerlightuponaccountofthatrelation。Thisdeterminationistheonlyeffectoftheresemblance；andthereforemustbethesamewithpowerorefficacy，whoseideaisderiv’dfromtheresemblance。Theseveralinstancesofresemblingconjunctionsleadusintothenotionofpowerandnecessity。Theseinstancesareinthemselvestotallydistinctfromeachother，andhavenounionbutinthemind，whichobservesthem，andcollectstheirideas。Necessity，then，istheeffectofthisobservation，andisnothingbutaninternalimpressionof。themind，oradeterminationtocarryourthoughtsfromoneobjecttoanother。Withoutconsideringitinthisview，wecanneverarriveatthemostdistantnotionofit，orbeabletoattributeiteithertoexternalorinternalobjects，tospiritorbody，tocausesoreffects。
Thenecessaryconnexionbetwixtcausesandeffectsisthefoundationofourinferencefromonetotheother。Thefoundationofourinferenceisthetransitionarisingfromtheaccustomedunion。Theseare，therefore，thesame。
Theideaofnecessityarisesfromsomeimpression。Thereisnoimpressionconvey’dbyoursenses，whichcangiverisetothatidea。Itmust，therefore，bederiv’dfromsomeinternalimpression，orimpressionofreflection。Thereisnointernalimpression，whichhasanyrelationtothepresentbusiness，butthatpropensity，whichcustomproduces，topassfromanobjecttotheideaofitsusualattendant。Thisthereforeistheessenceofnecessity。Uponthewhole，necessityissomething，thatexistsinthemind，notinobjects；nor-isitpossibleforusevertoformthemostdistantideaofit，consideredasaqualityinbodies。Eitherwehavenoideaofnecessity，ornecessityisnothingbutthatdeterminationofthethoughttopassfromcausestoeffects，andfromeffectstocauses，accordingtotheirexperiencedunion。
Thusasthenecessity，whichmakestwotimestwoequaltofour，orthreeanglesofatriangleequaltotworightones，liesonlyintheactoftheunderstanding，bywhich-weconsiderandcomparetheseideas；inlikemannerthenecessityorpower，whichunitescausesandeffects，liesinthedeterminationofthemindtopassfromtheonetotheother。Theefficacyor’energyofcausesisneitherplac’dinthecausesthemselves，norinthedeity，norintheconcurrenceofthesetwoprinciples；butbelongsentirelytothesoul，whichconsiderstheunionoftwoormoreobjectsinallpastinstances。’Tisherethattherealpowerofcausesisplac’dalongwiththeirconnexionandnecessity。
Iamsensible，thatofalltheparadoxes，whichI，havehad，orshallhereafterhaveoccasiontoadvanceinthecourseofthistreatise，thepresentoneisthemostviolent，andthat’tismerelybydintofsolidproofandreasoningIcaneverhopeitwillhaveadmission，andovercometheinveterateprejudicesofmankind。Beforewearereconciledtothisdoctrine，howoftenmustwerepeattoourselves，thatthesimpleviewofanytwoobjectsoractions，howeverrelated，cannevergiveusanyidea，ofpower，orofaconnexionbetwixtthem:thatthisideaarisesfromtherepetitionoftheirunion:thattherepetitionneitherdiscoversnorcausesanythingintheobjects，buthasaninfluenceonlyonthemind，bythatcustomarytransitionitproduces:thatthiscustomarytransitionis，therefore，thesamewiththepowerandnecessity；whichareconsequentlyqualitiesofperceptions，notofobjects，andareinternallyfeltbythesoul，andnotperceivdexternallyinbodies？Thereiscommonlyanastonishmentattendingeverythingextraordinary；andthisastonishmentchangesimmediatelyintothehighestdegreeofesteemorcontempt，accordingasweapproveordisapproveofthesubject。Iammuchafraid，thattho’theforegoingreasoningappearstometheshortestandmostdecisiveimaginable；yetwiththegeneralityofreadersthebiassofthemindwillprevail，andgivethemaprejudiceagainstthepresentdoctrine。
Thiscontrarybiassiseasilyaccountedfor。’Tisacommonobservation，thatthemindhasagreatpropensitytospreaditselfonexternalobjects，andtoconjoinwiththemanyinternalimpressions，whichtheyoccasion，andwhichalwaysmaketheirappearanceatthesametimethattheseobjectsdiscoverthemselvestothesenses。Thusascertainsoundsandsmellsarealwaysfoundtoattendcertainvisibleobjects，wenaturallyimagineaconjunction，eveninplace，betwixttheobjectsandqualities，tho’thequalitiesbeofsuchanatureastoadmitofnosuchconjunction，andreallyexistnowhere。Butofthismorefully(30)hereafter。Meanwhile’tissufficienttoobserve，thatthesamepropensityisthereason，whywesupposenecessityandpowertolieintheobjectsweconsider，notinourmindthatconsidersthem；notwithstandingitisnotpossibleforustoformthemostdistantideaofthatquality，whenitisnottakenforthedeterminationofthemind，topassfromtheideaofanobjecttothatofitsusualattendant。
Buttho’thisbetheonlyreasonableaccountwecangiveofnecessity，thecontrarynotionif；sorivetedinthemindfromtheprinciplesabove-mention’d，thatIdoubtnotbutmysentimentswillbetreatedbymanyasextravagantandridiculous。What！theefficacyofcauseslieinthedeterminationofthemind！Asifcausesdidnotoperateentirelyindependentofthemind，andwou’dnotcontinuetheiroperation，eventho’therewasnomindexistenttocontemplatethem，orreasonconcerningthem。Thoughtmaywelldependoncausesforitsoperation，butnotcausesonthought。Thisistoreversetheorderofnature，andmakethatsecondary，whichisreallyprimary，Toeveryoperationthereisapowerproportioned；andthispowermustbeplac’donthebody，thatoperates。Ifweremovethepowerfromonecause，wemustascribeittoanother:Buttoremoveitfromallcauses，andbestowitonabeing，thatisnowaysrelatedtothecauseoreffect，butbyperceivingthem，isagrossabsurdity，andcontrarytothemostcertainprinciplesofhumanreason。
Icanonlyreplytoallthesearguments，thatthecaseisheremuchthesame，asifablindmanshou’dpretendtofindagreatmanyabsurditiesinthesupposition，thatthecolourofscarletisnotthesamewiththesoundofatrumpet，norlightthesamewithsolidity。Ifwehavereallynoideaofapowerorefficacyinanyobject，orofanyrealconnexionbetwixtcausesandeffects，’twillbetolittlepurposetoprove，thatanefficacyisnecessaryinalloperations。Wedonotunderstandourownmeaningintalkingso，butignorantlyconfoundideas，whichareentirelydistinctfromeachother。Iam，indeed，readytoallow，thattheremaybeseveralqualitiesbothinmaterialandimmaterialobjects，withwhichweareutterlyunacquainted；andifwepleasetocallthesepowerorefficacy，’twillbeoflittleconsequencetotheworld。Butwhen，insteadofmeaningtheseunknownqualities，wemakethetermsofpowerandefficacysignifysomething，ofwhichwehaveaclearidea，andwhichisincompatiblewiththoseobjects，towhichweapplyit，obscurityanderrorbeginthentotakeplace，andweareledastraybyafalsephilosophy。Thisisthecase，whenwetransferthedeterminationofthethoughttoexternalobjects，andsupposeanyrealintelligibleconnexionbetwixtthem；thatbeingaquality，whichcanonlybelongtothemindthatconsidersthem。
Astowhatmaybesaid，thattheoperationsofnatureareindependentofourthoughtandreasoning，Iallowit；andaccordinglyhaveobserv’d，thatobjectsbeartoeachothertherelationsofcontiguityandsuccession:thatlikeobjectsmaybeobserv’dinseveralinstancestohavelikerelations；andthatallthisisindependentof，andantecedenttotheoperationsoftheunderstanding。Butifwegoanyfarther，andascribeapowerornecessaryconnexiontotheseobjects；thisiswhatwecanneverobserveinthem，butmustdrawtheideaofitfromwhatwefeelinternallyincontemplatingthem。AndthisIcarrysofar，thatIamreadytoconvertmypresentreasoningintoaninstanceofit，byasubtility，whichitwillnotbedifficulttocomprehend。
Whenanyobjectispresentedtous，itimmediatelyconveystothemindalivelyideaofthatobject，whichisusuallyfoundtoattendit；andthisdeterminationofthemindformsthenecessaryconnexionoftheseobjects。Butwhenwechangethepointofview，fromtheobjectstotheperceptions；inthatcasetheimpressionistobeconsideredasthecause，andthelivelyideaastheeffect；andtheirnecessaryconnexionisthatnewdetermination，whichwefeeltopassfromtheideaoftheonetothatoftheother。Theunitingprincipleamongourinternalperceptionsisasunintelligibleasthatamongexternalobjects，andisnotknowntousanyotherwaythanbyexperience。Nowthenatureandeffectsofexperiencehavebeenalreadysufficientlyexamin’dandexplain’d。Itnevergivesusanyinsightintotheinternalstructureoroperatingprincipleofobjects，butonlyaccustomsthemindtopassfromonetoanother。
’Tisnowtimetocollectallthedifferentpartsofthisreasoning，andbyjoiningthemtogetherformanexactdefinitionoftherelationofcauseandeffect，whichmakesthesubjectofthepresentenquiry。Thisorderwou’dnothavebeenexcusable，offirstexaminingourinferencefromtherelationbeforewehadexplain’dtherelationitself，haditbeenpossibletoproceedinadifferentmethod。Butasthenatureoftherelationdependssomuchonthatoftheinference，wehavebeenoblig’dtoadvanceinthisseeminglypreposterousmanner，andmake-useoftermsbeforewewereableexactlytodefinethem，orfixtheirmeaning。Weshallnowcorrectthisfaultbygivingaprecisedefinitionofcauseandeffect。
Theremaytwodefinitionsbegivenofthisrelation，whichareonlydifferent，bytheirpresentingadifferentviewofthesameobject，andmakingusconsideriteitherasaphilosophicalorasanaturalrelation；eitherasacomparisonoftwoideas，orasanassociationbetwixtthem。WemaydefineaCAUSEtobe’Anobjectprecedentandcontiguoustoanother，andwherealltheobjectsresemblingtheformerareplac’dinlikerelationsofprecedencyandcontiguitytothoseobjectsthatresemblethelatter。’IIfthisdefinitionbeesteem’ddefective，becausedrawnfromobjectsforeigntothecause，wemaysubstitutethisotherdefinitioninitsplace，viz。’ACAUSEisanobjectprecedentandcontiguoustoanother，andsounitedwithit，thattheidea，oftheonedeterminesthemindtoformtheideaoftheother，andtheimpressionoftheonetoformamorelivelyideaoftheother。’2Shou’dthisdefinitionalsoberejectedforthesamereason，Iknownootherremedy，thanthatthepersons，whoexpressthisdelicacy，shou’dsubstituteajusterdefinitioninitsplace。ButformypartImustownmyincapacityforsuchanundertaking。WhenIexaminewiththeutmostaccuracythoseobjects，whicharecommonlydenominatedcausesandeffects，Ifind，inconsideringasingleinstance，thattheoneobjectisprecedentandcontiguoustotheother；andininlargingmyviewtoconsiderseveralinstances，Ifindonly，thatlikeobjectsareconstantlyplac’dinlikerelationsofsuccessionandcontiguity。Again，whenIconsidertheinfluenceofthisconstantconjunction，Iperceive，thatsucharelationcanneverbeanobjectofreasoning，andcanneveroperateuponthemind，butbymeansofcustom，whichdeterminestheimaginationtomakeatransitionfromtheideaofoneobjecttothatofitsusualattendant，andfromtheimpressionofonetoamorelivelyideaoftheother。Howeverextraordinarythesesentimentsmayappear，Ithinkitfruitlesstotroublemyselfwithanyfartherenquiryorreasoninguponthesubject，butshallreposemyselfonthemasonestablishedmaxims。
’Twillonlybeproper，beforeweleavethissubject，todrawsomecorrollariesfromit，bywhichwemayremoveseveralprejudicesandpopularerrors，thathaveverymuchprevail’dinphilosophy。First，Wemaylearnfromtheforegoing，doctrine，thatallcausesareofthesamekind，andthatinparticularthereisnofoundationforthatdistinction，whichwesometimesmakebetwixtefficientcausesandcausessinequanon；orbetwixtefficientcauses，andformal，andmaterial，andexemplary，andfinalcauses。Forasourideaofefficiencyisderiv’dfromtheconstantconjunctionoftwoobjects，whereverthisisobserv’d，thecauseisefficient；andwhereitisnot，therecanneverbeacauseofanykind。Forthesamereasonwemustrejectthedistinctionbetwixtcauseandoccasion，whensuppos’dtosignifyanythingessentiallydifferentfromeachother。Ifconstantconjunctionbeimply’dinwhatwecalloccasion，’tisarealcause。Ifnot，’tisnorelationatall，andcannotgiverisetoanyargumentorreasoning。
Secondly，Thesamecourseofreasoningwillmakeusconclude，thatthereisbutonekindofnecessity，asthereisbutonekindofcause，andthatthecommondistinctionbetwixtmoralandphysicalnecessityiswithoutanyfoundationinnature。Thisclearlyappearsfromtheprecedentexplicationofnecessity。’Tistheconstantconjunctionofobjects，alongwiththedeterminationofthemind，whichconstitutesaphysicalnecessity:Andtheremovaloftheseisthesamethingwithchance。Asobjectsmusteitherbeconjoin’dornot，andasthemindmusteitherbedeterminedornottopassfromoneobjecttoanother，’tisimpossibletoadmitofanymediumbetwixtchanceandanabsolutenecessity。Inweakeningthisconjunctionanddeterminationyoudonotchangethenatureofthenecessity；sinceevenintheoperationofbodies，thesehavedifferentdegreesofconstancyandforce，withoutproducingadifferentspeciesofthatrelation。
Thedistinction，whichweoftenmakebetwixt
andtheofit，isequallywithoutfoundation。
Thirdly，Wemaynowbeablefullytoovercomeallthatrepugnance，which’tissonaturalforustoentertainagainsttheforegoingreasoning，bywhichweendeavour’dtoprove，thatthenecessityofacausetoeverybeginningofexistenceisnotfoundedonanyargumentseitherdemonstrativeorintuitive。Suchanopinionwillnotappearstrangeaftertheforegoingdefinitions。Ifwedefineacausetobeanobjectprecedentandcontiguoustoanother，andwherealltheobjectsresemblingthefarmerareplac’dinalikerelationof。priorityandcontiguitytothoseobjects，thatresemblethelatter；wemayeasilyconceive，thatthereisnoabsolutenormetaphysicalnecessity，thateverybeginningofexistenceshou’dbeattendedwithsuchanobject。Ifwedefineacausetobe，Anobjectprecedentandcontiguoustoanother，andsounitedwithitintheimagination，thattheideaoftheonedeterminesthemindtoformtheideaoftheother，andtheimpressionoftheonetoformamorelivelyideaoftheother；weshallmakestilllessdifficultyofassentingtothisopinion。Suchaninfluenceonthemindisinitselfperfectlyextraordinaryandincomprehensible；norcanwebecertainofitsreality，butfromexperienceandobservation。
Ishalladdasafourthcorrollarythatwecanneverhavereasontobelievethatanyobjectexists，ofwhichwecannotformanidea。Forasallourreasoningsconcerningexistencearederiv’dfromcausation，andasallourreasoningsconcerningcausationarederiv’dfromtheexperiencedconjunctionofobjects，notfromanyreasoningorreflection，thesameexperiencemustgiveusanotionoftheseobjects，andmustremoveallmysteryfromourconclusions。Thisissoevident，that’twou’dscarcehavemeritedourattention，wereitnottoobviatecertainobjectionsofthiskind，whichmightariseagainstthefollowingreasoningsconcerningmatterandsubstance。Ineednotobserve，thatafullknowledgeoftheobjectisnotrequisite，butonlyofthosequalitiesofit，whichwebelievetoexist。
RulesbywhichtojudgeofCausesandEffects。
Accordingtotheprecedentdoctrine，therearenoobjectswhichbythemeresurvey，withoutconsultingexperience，wecandeterminetobethecausesofanyother；andnoobjects，whichwecancertainlydetermineinthesamemannernottobethecauses。Anythingmayproduceanything。Creation，annihilation，motion，reason，volition；allthesemayarisefromoneanother，orfromanyotherobjectwecanimagine。Norwillthisappearstrange，ifwecomparetwoprinciplesexplain’dabove，thattheconstantconjunctionofobjectsdeterminestheircausation，and(31)that，propertyspeaking，noobjectsarecontrarytoeachotherbutexistenceandnon-existence。Whereobjectsarenotcontrary，nothinghindersthemfromhavingthatconstantconjunction，onwhichtherelationofcauseandeffecttotallydepends。
Sincetherefore’tispossibleforallobjectstobecomecausesoreffectstoeachother，itmaybepropertofixsomegeneralrules，bywhichwemayknowwhentheyreallyareso。
(1)Thecauseandeffectmustbecontiguousinspaceandtime。
(2)Thecausemustbepriortotheeffect。
(3)Theremustbeaconstantunionbetwixtthecauseandeffect。’Tischieflythisquality，thatconstitutestherelation。
(4)Thesamecausealwaysproducesthesameeffect，andthesameeffectneverarisesbutfromthesamecause。Thisprinciplewederivefromexperience，andisthesourceofmostofourphilosophicalreasonings。Forwhenbyanyclearexperimentwehavediscoveredthecausesoreffectsofanyphaenomenon，weimmediatelyextendourobservationtoeveryphenomenonofthesamekind，withoutwaitingforthatconstantrepetition，fromwhichthefirstideaofthisrelationisderiv’d。
(5)Thereisanotherprinciple，whichhangsuponthis，viz。thatwhereseveraldifferentobjectsproducethesameeffect，itmustbebymeansofsomequality，whichwediscovertobecommonamongstthem。Foraslikeeffectsimplylikecauses，wemustalwaysascribethecausationtothecircumstance，whereinwediscovertheresemblance。
(6)Thefollowingprincipleisfoundedonthesamereason。Thedifferenceintheeffectsoftworesemblingobjectsmustproceedfromthatparticular，inwhichtheydiffer。Foraslikecausesalwaysproducelikeeffects，wheninanyinstancewefindourexpectationtobedisappointed，wemustconcludethatthisirregularityproceedsfromsomedifferenceinthecauses。
(7)Whenanyobjectencreasesordiminisheswiththeencreaseordiminutionofitscause，’tistoberegardedasacompoundedeffect，deriv’dfromtheunionoftheseveraldifferenteffects，whicharisefromtheseveraldifferentpartsofthecause。Theabsenceorpresenceofonepartofthecauseisheresuppos’dtobealwaysattendedwiththeabsenceorpresenceofaproportionablepartoftheeffect。Thisconstantconjunctionsufficientlyproves，thattheonepartisthecauseoftheother。Wemust，however，bewarenottodrawsuchaconclusionfromafewexperiments。Acertaindegreeofheatgivespleasure；ifyoudiminishthatheat，thepleasurediminishes；butitdoesnotfollow，thatifyouaugmentitbeyondacertaindegree，thepleasurewilllikewiseaugment；forwefindthatitdegeneratesintopain。
(8)TheeighthandlastruleIshalltakenoticeofis，thatanobject，whichexistsforanytimeinitsfullperfectionwithoutanyeffect，isnotthesolecauseofthateffect，butrequirestobeassistedbysomeotherprinciple，whichmayforwarditsinfluenceandoperation。Foraslikeeffectsnecessarilyfollowfromlikecauses，andinacontiguoustimeandplace，theirseparationforamomentshews，thatthesecausesarenotcompleatones。
HereisalltheLOGICIthinkpropertoemployinmyreasoning；andperhapseventhiswasnotverynecessary，butmighthavebeensupplydbythenaturalprinciplesofourunderstanding。Ourscholastichead-piecesandlogiciansshewnosuchsuperiorityabovethemerevulgarintheirreasonandability，astogiveusanyinclinationtoimitatethemindeliveringalongsystemofrulesandpreceptstodirectourjudgment，inphilosophy。Alltherulesofthisnatureareveryeasyintheirinvention，butextremelydifficultintheirapplication；andevenexperimentalphilosophy，whichseemsthemostnaturalandsimpleofany，requirestheutmoststretchofhumanjudgment。Thereisnophaenomenoninnature，butwhatiscompoundedandmodifydbysomanydifferentcircumstances，thatinordertoarriveatthedecisivepoint，wemustcarefullyseparatewhateverissuperfluous，andenquirebynewexperiments，ifeveryparticularcircumstanceofthefirstexperimentwasessentialtoit。Thesenewexperimentsareliabletoadiscussionofthesamekind；sothattheutmostconstancyisrequirdtomakeuspersevereinourenquiry，andtheutmostsagacitytochoosetherightwayamongsomanythatpresentthemselves。Ifthisbethecaseeveninnaturalphilosophy，howmuchmoreinmoral，wherethereisamuchgreatercomplicationofcircumstances，andwherethoseviewsandsentiments，whichareessentialtoanyactionofthemind，aresoimplicitandobscure，thattheyoftenescapeourstrictestattention，andarenotonlyunaccountableintheircauses，butevenunknownintheirexistence？IammuchafraidlestthesmallsuccessImeetwithinmyenquirieswillmakethisobservationbeartheairofanapologyratherthanofboasting。
Ifanythingcangivemesecurityinthisparticular，’twillbetheenlargingofthesphereofmyexperimentsasmuchaspossible；forwhichreasonitmaybeproperinthisplacetoexaminethereasoningfacultyofbrutes，aswellasthatofhumancreatures。
OfthereasonofanimalsNexttotheridiculeofdenyinganevidenttruth，isthatoftakingmuchpainstodefendit；andnotruthappearstomemoreevident，thanthatbeastsareendowdwiththoughtandreasonaswellasmen。Theargumentsareinthiscasesoobvious，thattheyneverescapethemoststupidandignorant。
Weareconscious，thatweourselves，inadaptingmeanstoends，areguidedbyreasonanddesign，andthat’tisnotignorantlynorcasuallyweperformthoseactions，whichtendtoself-preservation，totheobtainingpleasure，andavoidingpain。Whenthereforeweseeothercreatures，inmillionsofinstances，performlikeactions，anddirectthemtotheends，allourprinciplesofreasonandprobabilitycarryuswithaninvincibleforcetobelievetheexistenceofalikecause。’Tisneedlessinmyopiniontoillustratethisargumentbytheenumerationofparticulars。Thesmallestattentionwillsupplyuswithmorethanarerequisite。Theresemblancebetwixttheactionsofanimalsandthoseofmenissoentireinthisrespect，thattheveryfirstactionofthefirstanimalweshallpleasetopitchon，willaffordusanincontestableargumentforthepresentdoctrine。
Thisdoctrineisasusefulasitisobvious，andfurnishesuswithakindoftouchstone，bywhichwemaytryeverysysteminthisspeciesofphilosophy。’Tisfromtheresemblanceoftheexternalactionsofanimalstothoseweourselvesperform，thatwejudgetheirinternallikewisetoresembleours；andthesameprincipleofreasoning，carrydonestepfarther，willmakeusconcludethatsinceourinternalactionsresembleeachother，thecauses，fromwhichtheyarederivd，mustalsoberesembling。Whenanyhypothesis，therefore，isadvancdtoexplainamentaloperation，whichiscommontomenandbeasts，wemustapplythesamehypothesistoboth；andaseverytruehypothesiswillabidethistrial，soImayventuretoaffirm，thatnofalseonewilleverbeabletoendureit。Thecommondefectofthosesystems，whichphilosophershaveemploydtoaccountfortheactionsofthemind，is，thattheysupposesuchasubtilityandrefinementofthought，asnotonlyexceedsthecapacityofmereanimals，butevenofchildrenandthecommonpeopleinourownspecies；whoarenotwithstandingsusceptibleofthesameemotionsandaffectionsaspersonsofthemostaccomplishdgeniusandunderstanding。Suchasubtilityisadearproofofthefalshood，asthecontrarysimplicityofthetruth，ofanysystem。
Letusthereforeputourpresentsystemconcerningthenatureoftheunderstandingtothisdecisivetrial，andseewhetheritwillequallyaccountforthereasoningsofbeastsasfortheseofthehumanspecies。
Herewemustmakeadistinctionbetwixtthoseactionsofanimals，whichareofavulgarnature，andseemtobeonalevelwiththeircommoncapacities，andthosemoreextraordinaryinstancesofsagacity，whichtheysometimesdiscoverfortheirownpreservation，andthepropagationoftheirspecies。Adog，thatavoidsfireandprecipices，thatshunsstrangers，andcaresseshismaster，affordsusaninstanceofthefirstkind。Abird，thatchooseswithsuchcareandnicetytheplaceandmaterialsofhernest，andsitsuponhereggsforaduetime，andinsuitableseason，withalltheprecautionthatachymistiscapableofinthemostdelicateprojection，furnishesuswithalivelyinstanceofthesecond。
Astotheformeractions，Iasserttheyproceedfromareasoning，thatisnotinitselfdifferent，norfoundedondifferentprinciples，fromthatwhichappearsinhumannature。’Tisnecessaryinthefirstplace，thattherebesomeimpressionimmediatelypresenttotheirmemoryorsenses，inordertobethefoundationoftheirjudgment。Fromthetoneofvoicethedoginfershismastersanger，andforeseeshisownpunishment。Fromacertainsensationaffectinghissmell，hejudgeshisgamenottobefardistantfromhim。
Secondly，Theinferencehedrawsfromthepresentimpressionisbuiltonexperience，andonhisobservationoftheconjunctionofobjectsinpastinstances。Asyouvarythisexperience，hevarieshisreasoning。Makeabeatingfollowupononesignormotionforsometime，andafterwardsuponanother；andhewillsuccessivelydrawdifferentconclusions，accordingtohismostrecentexperience。
Nowletanyphilosophermakeatrial，andendeavourtoexplainthatactofthemind，whichwecallbelief，andgiveanaccountoftheprinciples，fromwhichitisderivd，independentoftheinfluenceofcustomontheimagination。andlethishypothesisbeequallyapplicabletobeastsastothehumanspecies；andafterhehasdonethis，Ipromisetoembracehisopinion。ButatthesametimeIdemandasanequitablecondition，thatifmysystembetheonlyone，whichcananswertoalltheseterms，itmaybereceivdasentirelysatisfactoryandconvincing。Andthat’tistheonlyone，isevidentalmostwithoutanyreasoning。Beastscertainlyneverperceiveanyrealconnexionamongobjects。’Tisthereforebyexperiencetheyinferonefromanother。Theycanneverbyanyargumentsformageneralconclusion，thatthoseobjects，ofwhichtheyhavehadnoexperience，resemblethoseofwhichtheyhave。’Tisthereforebymeansofcustomalone，thatexperienceoperatesuponthem。Allthiswassufficientlyevidentwithrespecttoman。Butwithrespecttobeaststherecannotbetheleastsuspicionofmistake；whichmustbeowndtobeastrongconfirmation，orratheraninvincibleproofofmysystem。
Nothingshewsmoretheforceofhabitinreconcilingustoanyphaenomenoun，thanthis，thatmenarenotastonish’dattheoperationsoftheirownreason，atthesametime，thattheyadmiretheinstinctofanimals，andfindadifficultyinexplainingit，merelybecauseitcannotbereducdtotheverysameprinciples。Toconsiderthematteraright，reasonisnothingbutawonderfulandunintelligibleinstinctinoursouls，whichcarriesusalongacertaintrainofideas，andendowsthemwithparticularqualities，accordingtotheirparticularsituationsandrelations。Thisinstinct，’tistrue，arisesfrompastobservationandexperience；butcananyonegivetheultimatereason，whypastexperienceandobservationproducessuchaneffect，anymorethanwhynaturealoneshoudproduceit？Naturemaycertainlyproducewhatevercanarisefromhabit:Nay，habitisnothingbutoneoftheprinciplesofnature，andderivesallitsforcefromthatorigin。