of　the　other。　　And　as　regards　God；　if　my　mind　were　not　pre…occupied　with　prejudices；　and　if　my　thought　did　not　find　itself　on　all　hands　diverted　by　the　continual　pressure　of　sensible　things；　there　would　be　nothing　which　I　could　know　more　immediately　and　more　easily　than　Him。　　For　is　there　anything　more　manifest　than　that　there　is　a　God；　that　is　to　say；　a　Supreme　Being；　to　whose　essence　alone　existence　pertains？21　　　　　　And　although　for　a　firm　grasp　of　this　truth　I　have　need　of　a　strenuous　application　of　mind；　at　present　I　not　only　feel　myself　to　be　as　assured　of　it　as　of　all　that　I　hold　as　most　certain；　but　I　also　remark　that　the　certainty　of　all　other　things　depends　on　it　so　absolutely；　that　without　this　knowledge　it　is　impossible　ever　to　know　anything　perfectly。　　　　　　For　although　I　am　of　such　a　nature　that　as　long　as22　I　understand　anything　very　clearly　and　distinctly；　I　am　naturally　impelled　to　believe　it　to　be　true；　yet　because　I　am　also　of　such　a　nature　that　I　cannot　have　my　mind　constantly　fixed　on　the　same　object　in　order　to　perceive　it　clearly；　and　as　I　often　recollect　having　formed　a　past　judgment　without　at　the　same　time　properly　recollecting　the　reasons　that　led　me　to　make　it；　it　may　happen　meanwhile　that　other　reasons　present　themselves　to　me；　which　would　easily　cause　me　to　change　my　opinion；　if　I　were　ignorant　of　the　facts　of　the　existence　of　God；　and　thus　I　should　have　no　true　and　certain　knowledge；　but　only　vague　and　vacillating　opinions。　　Thus；　for　example；　when　I　consider　the　nature　of　a　＇rectilinear＇　triangle；　I　who　have　some　little　knowledge　of　the　principles　of　geometry　recognise　quite　clearly　that　the　three　angles　are　equal　to　two　right　angles；　and　it　is　not　possible　for　me　not　to　believe　this　so　long　as　I　apply　my　mind　to　its　demonstration；　but　so　soon　as　I　abstain　from　attending　to　the　proof；　although　I　still　recollect　having　clearly　comprehended　it；　it　may　easily　occur　that　I　come　to　doubt　its　truth；　if　I　am　ignorant　of　there　being　a　God。　　For　I　can　persuade　myself　of　having　been　so　constituted　by　nature　that　I　can　easily　deceive　myself　even　in　those　matters　which　I　believe　myself　to　apprehend　with　the　greatest　evidence　and　certainty；　especially　when　I　recollect　that　I　have　frequently　judged　matters　to　be　true　and　certain　which　other　reasons　have　afterwards　impelled　me　to　judge　to　be　altogether　false。　　　　　　But　after　I　have　recognised　that　there　is　a　God￥because　at　the　same　time　I　have　also　recognised　that　all　things　depend　upon　Him；　and　that　He　is　not　a　deceiver；　and　from　that　have　inferred　that　what　I　perceive　clearly　and　distinctly　cannot　fail　to　be　true￥although　I　no　longer　pay　attention　to　the　reasons　for　which　I　have　judged　this　to　be　true；　provided　that　I　recollect　having　clearly　and　distinctly　perceived　it　no　contrary　reason　can　be　brought　forward　which　could　ever　cause　me　to　doubt　of　its　truth；　and　thus　I　have　a　true　and　certain　knowledge　of　it。　　And　this　same　knowledge　extends　likewise　to　all　other　things　which　I　recollect　having　formerly　demonstrated；　such　as　the　truths　of　geometry　and　the　like；　for　what　can　be　alleged　against　them　to　cause　me　to　place　them　in　doubt？　　Will　it　be　said　that　my　nature　is　such　as　to　cause　me　to　be　frequently　deceived？　　But　I　already　know　that　I　cannot　be　deceived　in　the　judgment　whose　grounds　I　know　clearly。　Will　it　be　said　that　I　formerly　held　many　things　to　be　true　and　certain　which　I　have　afterwards　recognised　to　be　false？　But　I　had　not　had　any　clear　and　distinct　knowledge　of　these　things；　and　not　as　yet　knowing　the　rule　whereby　I　assure　myself　of　the　truth；　I　had　been　impelled　to　give　my　assent　from　reasons　which　I　have　since　recognised　to　be　less　strong　than　I　had　at　the　time　imagined　them　to　be。　　What　further　objection　can　then　be　raised？　　That　possibly　I　am　dreaming　（an　objection　I　myself　made　a　little　while　ago）；　or　that　all　the　thoughts　which　I　now　have　are　no　more　true　than　the　phantasies　of　my　dreams？　　But　even　though　I　slept　the　case　would　be　the　same；　for　all　that　is　clearly　present　to　my　mind　is　absolutely　true。　　　　　　And　so　I　very　clearly　recognise　that　the　certainty　and　truth　of　all　knowledge　depends　alone　on　the　knowledge　of　the　true　God；　in　so　much　that；　before　I　knew　Him；　I　could　not　have　a　perfect　knowledge　of　any　other　thing。　　And　now　that　I　know　Him　I　have　the　means　of　acquiring　a　perfect　knowledge　of　an　infinitude　of　things；　not　only　of　those　which　relate　to　God　Himself　and　other　intellectual　matters；　but　also　of　those　which　pertain　to　corporeal　nature　in　so　far　as　it　is　the　object　of　pure　mathematics　＇which　have　no　concern　with　whether　it　exists　or　not＇。　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Meditation　VI。　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Of　the　Existence　of　Material　Things；　and　of　the　real　　　　　　　　　distinction　between　the　Soul　and　Body　of　Man。
  Nothing　further　now　remains　but　to　inquire　whether　material　things　exist。　　And　certainly　I　at　least　know　that　these　may　exist　in　so　far　as　they　are　considered　as　the　objects　of　pure　mathematics；　since　in　this　aspect　I　perceive　them　clearly　and　distinctly。　　For　there　is　no　doubt　that　God　possesses　the　power　to　produce　everything　that　I　am　capable　of　perceiving　with　distinctness；　and　I　have　never　deemed　that　anything　was　impossible　for　Him；　unless　I　found　a　contradiction　in　attempting　to　conceive　it　clearly。　　Further；　the　faculty　of　imagination　which　I　possess；　and　of　which；　experience　tells　me；　I　make　use　when　I　apply　myself　to　the　consideration　of　material　things；　is　capable　of　persuading　me　of　their　existence；　for　when　I　attentively　consider　what　imagination　is；　I　find　that　it　is　nothing　but　a　certain　application　of　the　faculty　of　knowledge　to　the　body　which　is　immediately　present　to　it；　and　which　therefore　exists。　　　　　　And　to　render　this　quite　clear；　I　remark　in　the　first　place　the　difference　that　exists　between　the　imagination　and　pure　intellection　＇or　conception23＇。　　For　example；　when　I　imagine　a　triangle；　I　do　not　conceive　it　only　as　a　figure　comprehended　by　three　lines；　but　I　also　apprehend24　these　three　lines　as　present　by　the　power　and　inward　vision　of　my　mind；25　and　this　is　what　I　call　imagining。　　But　if　I　desire　to　think　of　a　chiliagon；　I　certainly　conceive　truly　that　it　is　a　figure　composed　of　a　thousand　sides；　just　as　easily　as　I　conceive　of　a　triangle　that　it　is　a　figure　of　three　sides　only；　but　I　cannot　in　any　way　imagine　the　thousand　sides　of　a　chiliagon　＇as　I　do　the　three　sides　of　a　triangle＇；　nor　do　I；　so　to　speak；　regard　them　as　present　＇with　the　eyes　of　my　mind＇。　　And　although　in　accordance　with　the　habit　I　have　formed　of　always　employing　the　aid　of　my　imagination　when　I　think　of　corporeal　things；　it　may　happen　that　in　imagining　a　chiliagon　I　confusedly　represent　to　myself　some　figure；　yet　it　is　very　evident　that　this　figure　is　not　a　chiliagon；　since　it　in　no　way　differs　from　that　which　I　represent　to　myself　when　I　think　of　a　myriagon　or　any　other　many…sided　figure；　nor　does　it　serve　my　purpose　in　discovering　the　properties　which　go　to　form　the　distinction　between　a　chiliagon　and　other　polygons。　But　if　the　question　turns　upon　a　pentagon；　it　is　quite　true　that　I　can　conceive　its　figure　as　well　as　that　of　a　chiliagon　without　the　help　of　my　imagination；　but　I　can　also　imagine　it　by　applying　the　attention　of　my　mind　to　each　of　its　five　sides；　and　at　the　same　time　to　the　space　which　they　enclose。　And　thus　I　clearly　recognise　that　I　have　need　of　a　particular　effort　of　mind　in　order　to　effect　the　act　of　imagination；　such　as　I　do　not　require　in　order　to　understand；　and　this　particular　effort　of　mind　clearly　manifests　the　difference　which　exists　between　imagination　and　pure　intellection。26　　　　　　I　remark　besides　that　this　power　of　imagination　which　is　in　one；　inasmuch　as　it　differs　from　the　power　of　understanding；　is　in　no　wise　a　necessary　element　in　my　nature；　or　in　＇my　essence；　that　is　to　say；　in＇　the　essence　of　my　mind；　for　although　I　did　not　possess　it　I　should　doubtless　ever　remain　the　same　as　I　now　am；　from　which　it　appears　that　we　might　conclude　that　it　depends　on　something　which　differs　from　me。　　And　I　easily　conceive　that　if　some　body　exists　with　which　my　mind　is　conjoined　and　united　in　such　a　way　that　it　can　apply　itself　to　consider　it　when　it　pleases；　it　may　be　that　by　this　means　it　can　imagine　corporeal　objects；　so　that　this　mode　of　thinking　differs　from　pure　intellection　only　inasmuch　as　mind　in　its　intellectual　activity　in　some　manner　turns　on　itself；　and　considers　some　of　the　ideas　which　it　possesses　in　itself；　while　in　imagining　it　turns　towards　the　body；　and　there　beholds　in　it　something　conformable　to　the　idea　which　it　has　either　conceived　of　itself　or　perceived　by　the　senses。　　I　easily　understand；　I　say；　that　the　imagination　could　be　thus　constituted　if　it　is　true　that　body　exists；　and　because　I　can　discover　no　other　convenient　mode　of　explaining　it；　I　conjecture　with　probability　that　body　does　exist；　but　this　is　only　with　probability；　and　although　I　examine　all　things　with　care；　I　nevertheless　do　not　find　that　from　this　distinct　idea　of　corporeal　nature；　which　I　have　in　my　imagination；　I　can　derive　any　argument　from　which　there　will　necessarily　be　deduced　the　existence　of　body。　　　　　　But　I　am　in　the　habit　of　imagining　many　other　things　besides　this　corporeal　nature　which　is　the