meditations on first philosophy-第15章

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　into　the　judgments　I　make。　　Only　here　a　new　difficulty　is　presented￥one　respecting　those　things　the　pursuit　or　avoidance　of　which　is　taught　me　by　nature；　and　also　respecting　the　internal　sensations　which　I　possess；　and　in　which　I　seem　to　have　sometimes　detected　error　＇and　thus　to　be　directly　deceived　by　my　own　nature＇。　　To　take　an　example；　the　agreeable　taste　of　some　food　in　which　poison　has　been　intermingled　may　induce　me　to　partake　of　the　poison；　and　thus　deceive　me。　　It　is　true；　at　the　same　time；　that　in　this　case　nature　may　be　excused；　for　it　only　induces　me　to　desire　food　in　which　I　find　a　pleasant　taste；　and　not　to　desire　the　poison　which　is　unknown　to　it；　and　thus　I　can　infer　nothing　from　this　fact；　except　that　my　nature　is　not　omniscient；　at　which　there　is　certainly　no　reason　to　be　astonished；　since　man；　being　finite　in　nature；　can　only　have　knowledge　the　perfectness　of　which　is　limited。　　　　　　But　we　not　unfrequently　deceive　ourselves　even　in　those　things　to　which　we　are　directly　impelled　by　nature；　as　happens　with　those　who　when　they　are　sick　desire　to　drink　or　eat　things　hurtful　to　them。　　It　will　perhaps　be　said　here　that　the　cause　of　their　deceptiveness　is　that　their　nature　is　corrupt；　but　that　does　not　remove　the　difficulty；　because　a　sick　man　is　none　the　less　truly　God's　creature　than　he　who　is　in　health；　and　it　is　therefore　as　repugnant　to　God's　goodness　for　the　one　to　have　a　deceitful　nature　as　it　is　for　the　other。　　And　as　a　clock　composed　of　wheels　and　counter…weights　no　less　exactly　observes　the　laws　of　nature　when　it　is　badly　made；　and　does　not　show　the　time　properly；　than　when　it　entirely　satisfies　the　wishes　of　its　maker；　and　as；　if　I　consider　the　body　of　a　man　as　being　a　sort　of　machine　so　built　up　and　composed　of　nerves；　muscles；　veins；　blood　and　skin；　that　though　there　were　no　mind　in　it　at　all；　it　would　not　cease　to　have　the　same　motions　as　at　present；　exception　being　made　of　those　movements　which　are　due　to　the　direction　of　the　will；　and　in　consequence　depend　upon　the　mind　＇as　apposed　to　those　which　operate　by　the　disposition　of　its　organs＇；　I　easily　recognise　that　it　would　be　as　natural　to　this　body；　supposing　it　to　be；　for　example；　dropsical；　to　suffer　the　parchedness　of　the　throat　which　usually　signifies　to　the　mind　the　feeling　of　thirst；　and　to　be　disposed　by　this　parched　feeling　to　move　the　nerves　and　other　parts　in　the　way　requisite　for　drinking；　and　thus　to　augment　its　malady　and　do　harm　to　itself；　as　it　is　natural　to　it；　when　it　has　no　indisposition；　to　be　impelled　to　drink　for　its　good　by　a　similar　cause。　　And　although；　considering　the　use　to　which　the　clock　has　been　destined　by　its　maker；　I　may　say　that　it　deflects　from　the　order　of　its　nature　when　it　does　not　indicate　the　hours　correctly；　and　as；　in　the　same　way；　considering　the　machine　of　the　human　body　as　having　been　formed　by　God　in　order　to　have　in　itself　all　the　movements　usually　manifested　there；　I　have　reason　for　thinking　that　it　does　not　follow　the　order　of　nature　when；　if　the　throat　is　dry；　drinking　does　harm　to　the　conservation　of　health；　nevertheless　I　recognise　at　the　same　time　that　this　last　mode　of　explaining　nature　is　very　different　from　the　other。　　For　this　is　but　a　purely　verbal　characterisation　depending　entirely　on　my　thought；　which　compares　a　sick　man　and　a　badly　constructed　clock　with　the　idea　which　I　have　of　a　healthy　man　and　a　well　made　clock；　and　it　is　hence　extrinsic　to　the　things　to　which　it　is　applied；　but　according　to　the　other　interpretation　of　the　term　nature　I　understand　something　which　is　truly　found　in　things　and　which　is　therefore　not　without　some　truth。　　　　　　But　certainly　although　in　regard　to　the　dropsical　body　it　is　only　so　to　speak　to　apply　an　extrinsic　term　when　we　say　that　its　nature　is　corrupted；　inasmuch　as　apart　from　the　need　to　drink；　the　throat　is　parched；　yet　in　regard　to　the　composite　whole；　that　is　to　say；　to　the　mind　or　soul　united　to　this　body；　it　is　not　a　purely　verbal　predicate；　but　a　real　error　of　nature；　for　it　to　have　thirst　when　drinking　would　be　hurtful　to　it。　　And　thus　it　still　remains　to　inquire　how　the　goodness　of　God　does　not　prevent　the　nature　of　man　so　regarded　from　being　fallacious。　　　　　　In　order　to　begin　this　examination；　then；　I　here　say；　in　the　first　place；　that　there　is　a　great　difference　between　mind　and　body；　inasmuch　as　body　is　by　nature　always　divisible；　and　the　mind　is　entirely　indivisible。　　For；　as　a　matter　of　fact；　when　I　consider　the　mind；　that　is　to　say；　myself　inasmuch　as　I　am　only　a　thinking　thing；　I　cannot　distinguish　in　myself　any　parts；　but　apprehend　myself　to　be　clearly　one　and　entire；　and　although　the　whole　mind　seems　to　be　united　to　the　whole　body；　yet　if　a　foot；　or　an　arm；　or　some　other　part；　is　separated　from　my　body；　I　am　aware　that　nothing　has　been　taken　away　from　my　mind。　　And　the　faculties　of　willing；　feeling；　conceiving；　etc。　cannot　be　properly　speaking　said　to　be　its　parts；　for　it　is　one　and　the　same　mind　which　employs　itself　in　willing　and　in　feeling　and　understanding。　　But　it　is　quite　otherwise　with　corporeal　or　extended　objects；　for　there　is　not　one　of　these　imaginable　by　me　which　my　mind　cannot　easily　divide　into　parts；　and　which　consequently　I　do　not　recognise　as　being　divisible；　this　would　be　sufficient　to　teach　me　that　the　mind　or　soul　of　man　is　entirely　different　from　the　body；　if　I　had　not　already　learned　it　from　other　sources。　　　　　　I　further　notice　that　the　mind　does　not　receive　the　impressions　from　all　parts　of　the　body　immediately；　but　only　from　the　brain；　or　perhaps　even　from　one　of　its　smallest　parts；　to　wit；　from　that　in　which　the　common　sense27　is　said　to　reside；　which；　whenever　it　is　disposed　in　the　same　particular　way；　conveys　the　same　thing　to　the　mind；　although　meanwhile　the　other　portions　of　the　body　may　be　differently　disposed；　as　is　testified　by　innumerable　experiments　which　it　is　unnecessary　here　to　recount。　　　　　　I　notice；　also；　that　the　nature　of　body　is　such　that　none　of　its　parts　can　be　moved　by　another　part　a　little　way　off　which　cannot　also　be　moved　in　the　same　way　by　each　one　of　the　parts　which　are　between　the　two；　although　this　more　remote　part　does　not　act　at　all。　　As；　for　example；　in　the　cord　ABCD　＇which　is　in　tension＇　if　we　pull　the　last　part　D；　the　first　part　A　will　not　be　moved　in　any　way　differently　from　what　would　be　the　case　if　one　of　the　intervening　parts　B　or　C　were　pulled；　and　the　last　part　D　were　to　remain　unmoved。　　And　in　the　same　way；　when　I　feel　pain　in　my　foot；　my　knowledge　of　physics　teaches　me　that　this　sensation　is　communicated　by　means　of　nerves　dispersed　through　the　foot；　which；　being　extended　like　cords　from　there　to　the　brain；　when　they　are　contracted　in　the　foot；　at　the　same　time　contract　the　inmost　portions　of　the　brain　which　is　their　extremity　and　place　of　origin；　and　then　excite　a　certain　movement　which　nature　has　established　in　order　to　cause　the　mind　to　be　affected　by　a　sensation　of　pain　represented　as　existing　in　the　foot。　　But　because　these　nerves　must　pass　through　the　tibia；　the　thigh；　the　loins；　the　back　and　the　neck；　in　order　to　reach　from　the　leg　to　the　brain；　it　may　happen　that　although　their　extremities　which　are　in　the　foot　are　not　affected；　but　only　certain　ones　of　their　intervening　parts　＇which　pass　by　the　loins　or　the　neck＇；　this　action　will　excite　the　same　movement　in　the　brain　that　might　have　been　excited　there　by　a　hurt　received　in　the　foot；　in　consequence　of　which　the　mind　will　necessarily　feel　in　the　foot　the　same　pain　as　if　it　had　received　a　hurt。　　And　the　same　holds　good　of　all　the　other　perceptions　of　our　senses。　　　　　　I　notice　finally　that　since　each　of　the　movements　which　are　in　the　portion　of　the　brain　by　which　the　mind　is　immediately　affected　brings　about　one　particular　sensation　only；　we　cannot　under　the　circumstances　imagine　anything　more　likely　than　that　this　movement；　amongst　all　the　sensations　which　it　is　capable　of　impressing　on　it；　causes　mind　to　be　affected　by　that　one　which　is　best　fitted　and　most　generally　useful　for　the　conservation　of　the　human　body　when　it　is　in　health。　　But　　experience　makes　us　aware　that　all　the　feelings　with　which　nature　inspires　us　are　such　as　I　have　just　spoken　of；　and　there　is　therefore　nothing　in　them　which　does　not　give　testimony　to　the　power　and　goodness　of　the　God　＇who　has　produced　them28＇。　　Thus；　for　example；　when　the　nerves　which　are　in　the　feet　are　violently　or　more　than　usually　moved；　their　movement；　passing　through　the　medulla　of　the　spine29　to　the　inmost　parts　of　the　brain；　gives　a　sign　to　the　mind　which　makes　it　feel　somewhat；　to　wit；　pain；　as　though　in　the　foot；　by　which　the　mind　is　excited　to　do　its　utmost　to　remove　the　cause　of　the　evil　as　dangerous　and　hurtful　to　the　foot。　　It　is　true　that　God　could　have　constituted　the　nature　of　man　in　such　a　way　that　this　same　movement　in　the　brain　would　have　conveyed　something　quite　different　to　the　mind；　for　example；　it　might　have　produced　consciousness　of　itself　either　in　so　far　as　it　is　in　the　brain；　or　as　it　is　in　the　foot；　or　as　it　is　in　some　other　place　between　the　foot　and　the　brain；　or　it　might　finally　have　produced　consciousness　of　anything　else　whatsoever；　but　none　of　all　this　would　have　contributed　so　well　to　the　conservation　of　the　body。　　Similarly；　when　we　desire　to　drink；　a　certain　dryness　of　the　throat　is　produced　which　moves　its　nerves；　and　by　their　means　the　internal　portions　of　the　brain；　and　this　movement　causes　in　the　mind　the　sensation　of　thirst；　because　in　this　case　there　is　nothing　more　useful　to　us　than　to　become　aware　that　we　have　need　to　drink　for　the　conservation　o　our　health；　and　the　same　holds　good　in　other　instances。　　　　　　From　this　it　is　quite　clear　that；　notwithstanding　the　supreme　goodness　of　God；　the　nature　of　man；　inasmuch　as　it　is　composed　of　mind　and　body；　cannot　be　otherwise　than　sometimes　a　source　of　deception。　　For　if　there　is　any　cause　which　excites；　not　in　the　foot　but　in　some　part　of　the　nerves　which　are　extended　between　the　foot　and　the　brain；　or　even　in　the　brain　itself；　the　same　movement　which　usually　is　produced　when　the　foot　is　detrimentally　affected；　pain　will　be　experienced　as　though　it　were　in　the　foot；　and　the　sense　will　thus　naturally　be　deceived；　for　since　the　same　movement　in　the　brain　is　capable　of　causing　but　one　sensation　in　the　mind；　and　this　sensation　is　much　more　frequently　excited　by　a　cause　which　hurts　the　foot　than　by　another　existing　in　some　other　quarter；　it　is　reasonable　that　it　should　convey　to　the　mind　pain　in　the　foot　rather　than　in　any　other　part　of　the　body。　And　although　the　parchedness　of　the　throat　does　not　always　proceed；　as　it　usually　does；　from　the　fact　that　drinking　is　necessary　for　the　health　of　the　body；　but　sometimes　comes　from　quite　a　different　cause；　as　is　the　case　with　dropsical　patients；　it　is　yet　much　better　that　it　should　mislead　on　this　occasion　than　if；　on　the　other　hand；　it　were　always　to　deceive　us　when　the　body　is　in　good　health；　and　so　on　in　similar　cases。　　　　　　And　certainly　this　consideration　is　of　great　service　to　me；　not　only　in　enabling　me　to　recognise　all　the　errors　to　which　my　nature　is　subject；　but　also　in　enabling　me　to　avoid　them　or　to　correct　them　more　easily。　　for　knowing　that　all　my　senses　more　frequently　indicate　to　me　truth　than　falsehood　respecting　the　things　which　concern　that　which　is　beneficia