prior analytics-第17节

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'healthy'　is　substituted　for　'health'　and　'diseased'　for　'disease'。



For　it　is　not　true　to　say　that　being　healthy　cannot　belong　to　one



who　is　diseased。　But　unless　this　is　assumed　no　conclusion　results；



save　in　respect　of　possibility：　but　such　a　conclusion　is　not



impossible：　for　it　is　possible　that　health　should　belong　to　no　man。



Again　the　fallacy　may　occur　in　a　similar　way　in　the　middle　figure：　'it



is　not　possible　that　health　should　belong　to　any　disease；　but　it　is



possible　that　health　should　belong　to　every　man；　consequently　it　is



not　possible　that　disease　should　belong　to　any　man'。　In　the　third



figure　the　fallacy　results　in　reference　to　possibility。　For　health　and



diseae　and　knowledge　and　ignorance；　and　in　general　contraries；　may



possibly　belong　to　the　same　thing；　but　cannot　belong　to　one　another。



This　is　not　in　agreement　with　what　was　said　before：　for　we　stated　that



when　several　things　could　belong　to　the　same　thing；　they　could



belong　to　one　another。



　　It　is　evident　then　that　in　all　these　cases　the　fallacy　arises　from



the　setting　out　of　the　terms：　for　if　the　things　that　are　in　the



conditions　are　substituted；　no　fallacy　arises。　It　is　clear　then　that



in　such　premisses　what　possesses　the　condition　ought　always　to　be



substituted　for　the　condition　and　taken　as　the　term。







　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　35







　　We　must　not　always　seek　to　set　out　the　terms　a　single　word：　for　we



shall　often　have　complexes　of　words　to　which　a　single　name　is　not



given。　Hence　it　is　difficult　to　reduce　syllogisms　with　such　terms。



Sometimes　too　fallacies　will　result　from　such　a　search；　e。g。　the



belief　that　syllogism　can　establish　that　which　has　no　mean。　Let　A



stand　for　two　right　angles；　B　for　triangle；　C　for　isosceles



triangle。　A　then　belongs　to　C　because　of　B：　but　A　belongs　to　B　without



the　mediation　of　another　term：　for　the　triangle　in　virtue　of　its　own



nature　contains　two　right　angles；　consequently　there　will　be　no　middle



term　for　the　proposition　AB；　although　it　is　demonstrable。　For　it　is



clear　that　the　middle　must　not　always　be　assumed　to　be　an　individual



thing；　but　sometimes　a　complex　of　words；　as　happens　in　the　case



mentioned。







　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　36







　　That　the　first　term　belongs　to　the　middle；　and　the　middle　to　the



extreme；　must　not　be　understood　in　the　sense　that　they　can　always　be



predicated　of　one　another　or　that　the　first　term　will　be　predicated　of



the　middle　in　the　same　way　as　the　middle　is　predicated　of　the　last



term。　The　same　holds　if　the　premisses　are　negative。　But　we　must



suppose　the　verb　'to　belong'　to　have　as　many　meanings　as　the　senses　in



which　the　verb　'to　be'　is　used；　and　in　which　the　assertion　that　a



thing　'is'　may　be　said　to　be　true。　Take　for　example　the　statement　that



there　is　a　single　science　of　contraries。　Let　A　stand　for　'there



being　a　single　science'；　and　B　for　things　which　are　contrary　to　one



another。　Then　A　belongs　to　B；　not　in　the　sense　that　contraries　are　the



fact　of　there　being　a　single　science　of　them；　but　in　the　sense　that　it



is　true　to　say　of　the　contraries　that　there　is　a　single　science　of



them。



　　It　happens　sometimes　that　the　first　term　is　stated　of　the　middle；



but　the　middle　is　not　stated　of　the　third　term；　e。g。　if　wisdom　is



knowledge；　and　wisdom　is　of　the　good；　the　conclusion　is　that　there



is　knowledge　of　the　good。　The　good　then　is　not　knowledge；　though



wisdom　is　knowledge。　Sometimes　the　middle　term　is　stated　of　the　third；



but　the　first　is　not　stated　of　the　middle；　e。g。　if　there　is　a



science　of　everything　that　has　a　quality；　or　is　a　contrary；　and　the



good　both　is　a　contrary　and　has　a　quality；　the　conclusion　is　that



there　is　a　science　of　the　good；　but　the　good　is　not　science；　nor　is



that　which　has　a　quality　or　is　a　contrary；　though　the　good　is　both



of　these。　Sometimes　neither　the　first　term　is　stated　of　the　middle；



nor　the　middle　of　the　third；　while　the　first　is　sometimes　stated　of



the　third；　and　sometimes　not：　e。g。　if　there　is　a　genus　of　that　of



which　there　is　a　science；　and　if　there　is　a　science　of　the　good；　we



conclude　that　there　is　a　genus　of　the　good。　But　nothing　is



predicated　of　anything。　And　if　that　of　which　there　is　a　science　is　a



genus；　and　if　there　is　a　science　of　the　good；　we　conclude　that　the



good　is　a　genus。　The　first　term　then　is　predicated　of　the　extreme；　but



in　the　premisses　one　thing　is　not　stated　of　another。



　　The　same　holds　good　where　the　relation　is　negative。　For　'that　does



not　belong　to　this'　does　not　always　mean　that　'this　is　not　that'；



but　sometimes　that　'this　is　not　of　that'　or　'for　that'；　e。g。　'there　is



not　a　motion　of　a　motion　or　a　becoming　of　a　becoming；　but　there　is　a



becoming　of　pleasure：　so　pleasure　is　not　a　becoming。'　Or　again　it



may　be　said　that　there　is　a　sign　of　laughter；　but　there　is　not　a



sign　of　a　sign；　consequently　laughter　is　not　a　sign。　This　holds　in　the



other　cases　too；　in　which　the　thesis　is　refuted　because　the　genus　is



asserted　in　a　particular　way；　in　relation　to　the　terms　of　the



thesis。　Again　take　the　inference　'opportunity　is　not　the　right　time：



for　opportunity　belongs　to　God；　but　the　right　time　does　not；　since



nothing　is　useful　to　God'。　We　must　take　as　terms　opportunity…right



time…God：　but　the　premiss　must　be　understood　according　to　the　case



of　the　noun。　For　we　state　this　universally　without　qualification；　that



the　terms　ought　always　to　be　stated　in　the　nominative；　e。g。　man；　good；



contraries；　not　in　oblique　cases；　e。g。　of　man；　of　a　good；　of



contraries；　but　the　premisses　ought　to　be　understood　with　reference　to



the　cases　of　each　term…either　the　dative；　e。g。　'equal　to　this'；　or　the



genitive；　e。g。　'double　of　this'；　or　the　accusative；　e。g。　'that　which



strikes　or　sees　this'；　or　the　nominative；　e。g。　'man　is　an　animal'；



or　in　whatever　other　way　the　word　falls　in　the　premiss。







　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　37







　　The　expressions　'this　belongs　to　that'　and　'this　holds　true　of　that'



must　be　understood　in　as　many　ways　as　there　are　different



categories；　and　these　categories　must　be　taken　either　with　or



without　qualification；　and　further　as　simple　or　compound：　the　same



holds　good　of　the　corresponding　negative　expressions。　We　must　consider



these　points　and　define　them　better。







　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　38







　　A　term　which　is　repeated　in　the　premisses　ought　to　be　joined　to



the　first　extreme；　not　to　the　middle。　I　mean　for　example　that　if　a



syllogism　should　be　made　proving　that　there　is　knowledge　of　justice；



that　it　is　good；　the　expression　'that　it　is　good'　（or　'qua　good'）



should　be　joined　to　the　first　term。　Let　A　stand　for　'knowledge　that　it



is　good'；　B　for　good；　C　for　justice。　It　is　true　to　predicate　A　of　B。



For　of　the　good　there　is　knowledge　that　it　is　good。　Also　it　is　true　to



predicate　B　of　C。　For　justice　is　identical　with　a　good。　In　this　way　an



analysis　of　the　argument　can　be　made。　But　if　the　expression　'that　it



is　good'　were　added　to　B；　the　conclusion　will　not　follow：　for　A　will



be　true　of　B；　but　B　will　not　be　true　of　C。　For　to　predicate　of　justice



the　term　'good　that　it　is　good'　is　false　and　not　intelligible。



Similarly　if　it　should　be　proved　that　the　healthy　is　an　object　of



knowledge　qua　good；　of　goat…stag　an　object　of　knowledge　qua　not



existing；　or　man　perishable　qua　an　object　of　sense：　in　every　case　in



which　an　addition　is　made　to　the　predicate；　the　addition　must　be



joined　to　the　extreme。



　　The　position　of　the　terms　is　not　the　same　when　something　is



established　without　qualification　and　when　it　is　qualified　by　some



attribute　or　condition；　e。g。　when　the　good　is　proved　to　be　an　object



of　knowledge　and　when　it　is　proved　to　be　an　object　of　knowledge　that



it　is　good。　If　it　has　been　proved　to　be　an　object　of　knowledge　without



qualification；　we　must　put　as　middle　term　'that　which　is'；　but　if　we



add　the　qualification　'that　it　is　good'；　the　middle　term　must　be　'that



which　is　something'。　Let　A　stand　for　'knowledge　that　it　is　something'；



B　stand　for　'something'；　and　C　stand　for　'good'。　It　is　true　to



predicate　A　of　B：　for　ex　hypothesi　there　is　a　science　of　that　which　is



something；　that　it　is　something。　B　too　is　true　of　C：　for　that　which



C　represents　is　something。　Consequently　A　is　true　of　C：　there　will



then　be　knowledge　of　the　good；　that　it　is　good：　for　ex　hypothesi　the



term　'something'　indicates　the　thing's　special　nature。　But　if



'being'　were　taken　as　middle　and　'being'　simply　were　joined　to　the



extreme；　not　'being　something'；　we　should　n