prior analytics-第26章

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AC；　we　have　a　reduction：　for　we　are　nearer　to　knowledge；　since　we　have



taken　a　new　term；　being　so　far　without　knowledge　that　A　belongs　to



C。　Or　again　suppose　that　the　terms　intermediate　between　B　and　C　are



few：　for　thus　too　we　are　nearer　knowledge。　For　example　let　D　stand　for



squaring；　E　for　rectilinear　figure；　F　for　circle。　If　there　were　only



one　term　intermediate　between　E　and　F　（viz。　that　the　circle　is　made



equal　to　a　rectilinear　figure　by　the　help　of　lunules）；　we　should　be



near　to　knowledge。　But　when　BC　is　not　more　probable　than　AC；　and　the



intermediate　terms　are　not　few；　I　do　not　call　this　reduction：　nor



again　when　the　statement　BC　is　immediate：　for　such　a　statement　is



knowledge。







　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　26







　　An　objection　is　a　premiss　contrary　to　a　premiss。　It　differs　from　a



premiss；　because　it　may　be　particular；　but　a　premiss　either　cannot



be　particular　at　all　or　not　in　universal　syllogisms。　An　objection　is



brought　in　two　ways　and　through　two　figures；　in　two　ways　because　every



objection　is　either　universal　or　particular；　by　two　figures　because



objections　are　brought　in　opposition　to　the　premiss；　and　opposites　can



be　proved　only　in　the　first　and　third　figures。　If　a　man　maintains　a



universal　affirmative；　we　reply　with　a　universal　or　a　particular



negative；　the　former　is　proved　from　the　first　figure；　the　latter



from　the　third。　For　example　let　stand　for　there　being　a　single



science；　B　for　contraries。　If　a　man　premises　that　contraries　are



subjects　of　a　single　science；　the　objection　may　be　either　that



opposites　are　never　subjects　of　a　single　science；　and　contraries　are



opposites；　so　that　we　get　the　first　figure；　or　that　the　knowable　and



the　unknowable　are　not　subjects　of　a　single　science：　this　proof　is



in　the　third　figure：　for　it　is　true　of　C　（the　knowable　and　the



unknowable）　that　they　are　contraries；　and　it　is　false　that　they　are



the　subjects　of　a　single　science。



　　Similarly　if　the　premiss　objected　to　is　negative。　For　if　a　man



maintains　that　contraries　are　not　subjects　of　a　single　science；　we



reply　either　that　all　opposites　or　that　certain　contraries；　e。g。



what　is　healthy　and　what　is　sickly；　are　subjects　of　the　same



science：　the　former　argument　issues　from　the　first；　the　latter　from



the　third　figure。



　　In　general　if　a　man　urges　a　universal　objection　he　must　frame　his



contradiction　with　reference　to　the　universal　of　the　terms　taken　by



his　opponent；　e。g。　if　a　man　maintains　that　contraries　are　not　subjects



of　the　same　science；　his　opponent　must　reply　that　there　is　a　single



science　of　all　opposites。　Thus　we　must　have　the　first　figure：　for



the　term　which　embraces　the　original　subject　becomes　the　middle　term。



　　If　the　objection　is　particular；　the　objector　must　frame　his



contradiction　with　reference　to　a　term　relatively　to　which　the　subject



of　his　opponent's　premiss　is　universal；　e。g。　he　will　point　out　that



the　knowable　and　the　unknowable　are　not　subjects　of　the　same



science：　'contraries'　is　universal　relatively　to　these。　And　we　have



the　third　figure：　for　the　particular　term　assumed　is　middle；　e。g。



the　knowable　and　the　unknowable。　Premisses　from　which　it　is　possible



to　draw　the　contrary　conclusion　are　what　we　start　from　when　we　try



to　make　objections。　Consequently　we　bring　objections　in　these



figures　only：　for　in　them　only　are　opposite　syllogisms　possible；　since



the　second　figure　cannot　produce　an　affirmative　conclusion。



　　Besides；　an　objection　in　the　middle　figure　would　require　a　fuller



argument；　e。g。　if　it　should　not　be　granted　that　A　belongs　to　B；



because　C　does　not　follow　B。　This　can　be　made　clear　only　by　other



premisses。　But　an　objection　ought　not　to　turn　off　into　other　things；



but　have　its　new　premiss　quite　clear　immediately。　For　this　reason　also



this　is　the　only　figure　from　which　proof　by　signs　cannot　be　obtained。



　　We　must　consider　later　the　other　kinds　of　objection；　namely　the



objection　from　contraries；　from　similars；　and　from　common　opinion；　and



inquire　whether　a　particular　objection　cannot　be　elicited　from　the



first　figure　or　a　negative　objection　from　the　second。







　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　27







　　A　probability　and　a　sign　are　not　identical；　but　a　probability　is　a



generally　approved　proposition：　what　men　know　to　happen　or　not　to



happen；　to　be　or　not　to　be；　for　the　most　part　thus　and　thus；　is　a



probability；　e。g。　'the　envious　hate'；　'the　beloved　show　affection'。



A　sign　means　a　demonstrative　proposition　necessary　or　generally



approved：　for　anything　such　that　when　it　is　another　thing　is；　or



when　it　has　come　into　being　the　other　has　come　into　being　before　or



after；　is　a　sign　of　the　other's　being　or　having　come　into　being。　Now



an　enthymeme　is　a　syllogism　starting　from　probabilities　or　signs；



and　a　sign　may　be　taken　in　three　ways；　corresponding　to　the　position



of　the　middle　term　in　the　figures。　For　it　may　be　taken　as　in　the　first



figure　or　the　second　or　the　third。　For　example　the　proof　that　a



woman　is　with　child　because　she　has　milk　is　in　the　first　figure：　for



to　have　milk　is　the　middle　term。　Let　A　represent　to　be　with　child；　B



to　have　milk；　C　woman。　The　proof　that　wise　men　are　good；　since



Pittacus　is　good；　comes　through　the　last　figure。　Let　A　stand　for　good；



B　for　wise　men；　C　for　Pittacus。　It　is　true　then　to　affirm　both　A　and　B



of　C：　only　men　do　not　say　the　latter；　because　they　know　it；　though



they　state　the　former。　The　proof　that　a　woman　is　with　child　because



she　is　pale　is　meant　to　come　through　the　middle　figure：　for　since



paleness　follows　women　with　child　and　is　a　concomitant　of　this



woman；　people　suppose　it　has　been　proved　that　she　is　with　child。　Let　A



stand　for　paleness；　B　for　being　with　child；　C　for　woman。　Now　if　the



one　proposition　is　stated；　we　have　only　a　sign；　but　if　the　other　is



stated　as　well；　a　syllogism；　e。g。　'Pittacus　is　generous；　since



ambitious　men　are　generous　and　Pittacus　is　ambitious。'　Or　again



'Wise　men　are　good；　since　Pittacus　is　not　only　good　but　wise。'　In　this



way　then　syllogisms　are　formed；　only　that　which　proceeds　through　the



first　figure　is　irrefutable　if　it　is　true　（for　it　is　universal）；



that　which　proceeds　through　the　last　figure　is　refutable　even　if　the



conclusion　is　true；　since　the　syllogism　is　not　universal　nor



correlative　to　the　matter　in　question：　for　though　Pittacus　is　good；　it



is　not　therefore　necessary　that　all　other　wise　men　should　be　good。　But



the　syllogism　which　proceeds　through　the　middle　figure　is　always



refutable　in　any　case：　for　a　syllogism　can　never　be　formed　when　the



terms　are　related　in　this　way：　for　though　a　woman　with　child　is



pale；　and　this　woman　also　is　pale；　it　is　not　necessary　that　she　should



be　with　child。　Truth　then　may　be　found　in　signs　whatever　their　kind；



but　they　have　the　differences　we　have　stated。



　　We　must　either　divide　signs　in　the　way　stated；　and　among　them



designate　the　middle　term　as　the　index　（for　people　call　that　the　index



which　makes　us　know；　and　the　middle　term　above　all　has　this



character）；　or　else　we　must　call　the　arguments　derived　from　the



extremes　signs；　that　derived　from　the　middle　term　the　index：　for



that　which　is　proved　through　the　first　figure　is　most　generally



accepted　and　most　true。



　　It　is　possible　to　infer　character　from　features；　if　it　is　granted



that　the　body　and　the　soul　are　changed　together　by　the　natural



affections：　I　say　'natural'；　for　though　perhaps　by　learning　music　a



man　has　made　some　change　in　his　soul；　this　is　not　one　of　those



affections　which　are　natural　to　us；　rather　I　refer　to　passions　and



desires　when　I　speak　of　natural　emotions。　If　then　this　were　granted



and　also　that　for　each　change　there　is　a　corresponding　sign；　and　we



could　state　the　affection　and　sign　proper　to　each　kind　of　animal；　we



shall　be　able　to　infer　character　from　features。　For　if　there　is　an



affection　which　belongs　properly　to　an　individual　kind；　e。g。　courage



to　lions；　it　is　necessary　that　there　should　be　a　sign　of　it：　for　ex



hypothesi　body　and　soul　are　affected　together。　Suppose　this　sign　is



the　possession　of　large　extremities：　this　may　belong　to　other　kinds



also　though　not　universally。　For　the　sign　is　proper　in　the　sense



stated；　because　the　affection　is　proper　to　the　whole　kind；　though



not　proper　to　it　alone；　according　to　our　usual　manner　of　speaking。　The



same　thing　then　will　be　found　in　another　kind；　and　man　may　be　brave；



and　some　other　kinds　of　animal　as　well。　They　will　then　have　the



sign：　for　ex　hypothesi　there　is　one　sign　corresponding　to　each



affection。　If　then　this　is　so；　and　we　can　collect　signs　of　this　sort



in　these　animals　which　have　only　one　affection　proper　to　them…but　each



affection　has　its　sign；　since　it　is　necessary　that　it　should　have　a



single　sign…we　shall　then　be　able　to　infer　character　from　features。



But　if　the　kind　as　a　whole　has　two　properties；　e。g。　if　the　lion　is



both　brave　and　generous；　how　shall　we　know　which　of　the　signs　which



are　its　proper　concomitants　is　the　sign　of　a　particular　affection？



Perhaps　if　both　belong　to　some　other　kind　though　not　to　the　whole　of



it；　and　if；　in　those　kinds　in　which　each　is　found　though　not　in　the



whole　of　their　members；　some　members　possess　one　of　the　affections　and



not　the　other：　e。g。　if　a　man　is　brave　but　not　generous；　but　possesses；



of　the　two　signs；　large　extremities；　it　is　clear　that　this　is　the　sign



of　courage　in　the　lion　also。　To　judge　character　from　features；　then；



is　possible　in　the　first　figure　if　the　middle　term　is　convertible　with



the　first　extreme；　but　is　wider　than　the　third　term　and　not



convertible　with　it：　e。g。　let　A　stand　for　courage；　B　for　large



extremities；　and　C　for　lion。　B　then　belongs　to　everything　to　which　C



belongs；　but　also　to　others。　But　A　belongs　to　everything　to　which　B



belongs；　and　to　nothing　besides；　but　is　convertible　with　B：　otherwise；



there　would　not　be　a　single　sign　correlative　with　each　affection。











　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　…THE　END…



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