criminal psychology-第38部分

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ny　analogous　cases？　The　activity　of　a　criminalist　is　of　far　too　short　duration　to　permit　him　to　experience　any　more　than　a　very　small　portion　of　the　possibilities　of　life；　and　suggestions　from　foreign　sources　are　very

＇1＇　ttingen：　Die　Moralstatistik。　Erlangen　1882。

　rare。　The　situation　is　different　in　other　disciplines。　‘‘Our　experience；''　says　James　Sully；''＇1＇　enables　us　to　express　a　number　of　additional　convictions。　We　can　predict　political　changes　and　scientific　developments；　and　can　conceive　of　the　geographical　conditions　at　the　north　pole。''　Other　disciplines　are　justified　to　assert　such　additional　propositions；　but　is　ours？　A　man　may　have　dealt　for　years　with　thieves　and　swindlers；　but　is　he　justified　in　deducing　from　the　inductions　made　in　his　experience；　the　situation　of　the　first　murderer　he　deals　with？　Is　he　right　in　translating　things　learned　by　dealing　with　educated　people　to　cases　where　only　peasants　appear？　In　all　these　cases　what　is　needed　in　making　deductions　is　great　caution　and　continual　reminder　to　be　very　careful；　for　our　work　here　still　lacks　the　proper　material。　In　addition　we　have　to　bear　in　mind　that　induction　is　intimately　related　to　analogy。　According　to　Lipps＇2＇　the　ground　of　one　is　the　ground　of　the　other；　they　both　rest　on　the　same　foundation。　‘‘If　I　am　still　in　doubt　whether　the　fact　on　which　a　moment　ago　I　depended　as　the　sufficient　condition　for　a　judgment　may　still　be　so　regarded；　the　induction　is　uncertain。　It　is　unjustified　when　I　take　for　sufficiently　valid　something　that　as　a　matter　of　fact　ought　not　to　be　so　taken。''　If　we　bear　in　mind　how　much　we　are　warned　against　the　use　of　analogy；　how　it　is　expressly　excluded　in　the　application　of　certain　criminal　laws；　and　how　dangerous　the　use　of　every　analogy　is；　we　must　be　convinced　that　the　use　for　our　cases　of　both　induction　and　analogy；　is　always　menace。　We　have　at　the　same　time　to　bear　in　mind　how　much　use　we　actually　make　of　both；　even　our　general　rulese。　g。；　concerning　false　testimony；bias；　reversibility；　special　inclinations；　etc。　and　our　doctrines　concerning　the　composition　and　indirection　of　testimony；　even　our　rules　concerning　the　value　of　witnesses　and　confessions；　all　these　depend　upon　induction　and　analogy。　We　pass　by　their　use　in　every　trial　from　case　to　case。　A　means　so　frequently　and　universally　used　must；　however；　be　altogether　reliable；　or　be　handled　with　the　greatest　care。　As　it　is　not　the　first　it　must　be　handled　in　the　second　way。

We　have　yet　to　indicate　the　various　ways　in　which　induction　may　be　used。　Fick　has　already　called　attention　to　the　astounding　question　concluding　Mill's　system　of　logic：　Why；　in　many　cases；　is　a　single　example　sufficient　to　complete　induction；　while　in　other　　cases　myriads　of　unanimous　instances　admitting　of　no　single　known　or　suspected　exception；　make　only　a　small　step　toward　the　establishment　of　a　generally　valid　judgment？


＇1＇　James　Sully：　‘‘Die　Illusionen''　in　Vol。　62　of　the　Internation。　Wissensohft　Bibliothek。　Leipzig　1884。

＇2＇　Th。　Lipps：　Grundtatssehen　des　Seelenlebens。　Bonn　1883。


This　question　is　of　enormous　significance　in　criminal　cases　because　it　is　not　easy　to　determine　in　any　particular　trial　whether　we　have　to　deal　with　a　situation　of　the　first　sort　where　a　single　example　is　evidential；　or　a　situation　of　the　second　sort　where　a　great　many　examples　fail　to　be　evidential。　On　this　difficulty　great　mistakes　depend；　particularly　mistakes　of　substitution　of　the　first　for　the　second。　We　are　satisfied　in　such　cases　with　a　few　examples　and　suppose　ourselves　to　have　proved　the　case　although　nothing　whatever　has　been　established。

We　must　see　first　of　all　if　it　is　of　any　use　to　refer　the　difficulty　of　the　matter　to　the　form　in　which　the　question　is　put；　and　to　say：　The　difficulty　results　from　the　question　itself。　If　it　be　asked；　‘‘Are　any　of　the　thousand　marbles　in　the　bag　white　marbles？''　the　question　is　determined　by　the　first　handful；　if　the　latter　brings　to　light　a　single　white　marble。　If；　however；　the　problem　is　phrased　so：　Does　the　bag　contain　white　marbles　_*only_？　then；　although　999　marbles　might　already　have　been　drawn　from　the　receptacle；　it　can　not　be　determined　that　the　last　marble　of　the　1000　is　white。　In　the　same　way；　if　people　assert　that　the　form　of　the　question　determines　the　answer；　it　does　not　follow　that　the　form　of　the　question　is　itself　determined　or　distinguished　inasmuch　as　the　object　belongs　to　the　first　or　the　second　of　the　above　named　categories。

A　safe　method　of　distinction　consists　in　calling　the　first　form　of　the　question　positive　and　the　second　negative。　The　positive　refers　to　a　single　unit；　the　negative　to　a　boundless　unit。　If　then　I　ask：　Are　there　any　white　marbles　whatever　in　the　bag？　the　answer　is　rendered　affirmative　by　the　discovery　of　a　single　white　marble。　But　if　the　question　is　phrased：　Are　there　_*only_　white　marbles　in　the　bag？　merely　its　form　is　positive　but　its　intent　is　negative。　To　conform　the　manner　of　the　question　to　its　intent；　it　would　be　necessary　to　ask：　Are　there　no　other　colors　than　white　among　the　marbles　in　the　bag？　And　inasmuch　as　the　negative　under　given　circumstances　is　in　many　ways　boundless；　the　question　admits　of　no　answer　until　the　last　marble　has　been　brought　to　light。　If　the　total　number　of　marbles　is　unlimited　the　question　can　receive　no　complete　inductive　answer　in　mathematical　form；　it　can　be　solved　only　approximately。　So　again；　if　one　asks：　Are　there　any　purely　blue　birds？　the　answer　is　affirmative　as　soon　as　a　single　completely　blue　bird　is　brought　to　　light。　But　if　the　question　is：　Do　not　also　striped　birds　exist？　no　answer　is　possible　until　the　very　last　bird　on　earth　is　exhibited。　In　that　way　only　could　the　possibility　be　excluded　that　not　one　of　the　terrestrial　fowls　is　striped。　As　a　matter　of　fact　we　are　satisfied　with　a　much　less　complete　induction。　So　we　say：　Almost　the　whole　earth　has　been　covered　by　naturalists　and　not　one　of　them　reports　having　observed　a　striped　bird；　hence　there　would　be　none　such　even　in　the　unexplored　parts　of　the　earth。　This　is　an　inductive　inference　and　its　justification　is　quite　another　question。

The　above　mentioned　distinction　may　be　made　still　clearer　if　instead　of　looking　back　to　the　form　of　the　question；　we　study　only　the　answer。　We　have　then　to　say　that　positive　statements　are　justified　by　the　existence　of　a　single　instance；　negative　assertions　only　by　the　complete　enumeration　of　all　possible　instances　and　never　at　all　if　the　instances　be　boundless。　That　the　negative　proof　always　requires　a　series　of　demonstrations　is　well　known；　the　one　thing　which　may　be　firmly　believed　is　the　fact　that　the　problem；　whether　a　single　example　is　sufficient；　or　a　million　are　insufficient；　is　only　a　form　of　the　problem　of　affirmative　and　negative　assertions。

So　then；　if　I　ask：　Has　A　ever　stolen　anything？　it　is　enough　to　record　one　judgment　against　him；　or　to　bring　one　witness　on　the　matter　in　order　to　establish　that　A　committed　theft　at　least　once　in　his　life。　If；　however；　it　is　to　be　proved　that　the　man　has　never　committed　a　theft；　his　whole　life　must　be　reviewed　point　by　point；　and　it　must　be　shown　that　at　no　instant　of　it　did　he　commit　larceny。　In　such　cases　we　are　content　with　much　less。　We　say　first　of　all：　We　will　not　inquire　whether　the　man　has　never　stolen。　We　will　see　merely　whether　he　was　never　punished　for　theft。　But　here；　too；　we　must　beware　and　not　commit　ourselves　to　inquiring　of　all　the　authorities　in　the　world；　but　only　of　a　single　authority；　who；　we　assume；　ought　to　know　whether　A　was　punished　or　not。　If　we　go　still　further；　we　say　that　inasmuch　as　we　have　not　heard　from　any　authorities　that　the　man　was　ever　punished　for　stealing；　we　suppose　that　the　man　was　never　punished　on　that　ground；　and　inasmuch　as　we　have　not　examined　anybody　who　had　seen　A　steal；　we　preferably　suppose　that　he　has　never　stolen。　This　is　what　we　call　satisfactory　evidence；　and　with　the　poor　means　at　our　disposal　it　must　suffice。

In　most　cases　we　have　to　deal　with　mixed　evidence；　and　frequently　it　has　become　habitual　to　change　the　problem　to　be　solved　according　to　our　convenience；　or　at　least　to　set　aside　some　one　thing。　Sup…　　pose　that　the　issue　deals　with　a　discovered；　well…retained　footprint　of　a　man。　We　then　suspect　somebody　and　compare　the　sole　of　his　shoe　with　the　impression。　They　fit　in　length　and　width；　in　the　number　of　nails　and　in　all　the　other　possible　indices；　and　we　therefore　assert：　It　is　the　footprint　of　the　suspect；　for　‘‘whose　footprint？''　is　the　problem　we　are　troubling　ourselves　to　solve。　In　truth　we　have　only　shown　that　the　particular　relations；　in　the　matter　of　length；　breadth；　number　of　nails；　etc。；　agree；　and　hence　we　regard　the　positive　part　of　the　evidence　as　sufficient　and　neglect　the　whole　troublesome　negative　part；　which　might　establish　the　fact　that　at　the　time　and　in　the　region　in　question；　nobody　was　or　could　be　whose　foot　could　accurately　fit　that　particular　footprint。　Therefore　we　have　not　proved　but　have　only　calculated　the　probability　that　at　the　time　there　might　possibly　not　have　been　another　person　with　a　shoe　of　similar　length；　breadth　and　number　of　nails。　The　probability　becomes　naturally　less　as　fewer　details　come　to　hand。　The　difficulty　lies　in　finding　where　such　probability；　which　stands　for　at　least　an　assumption；　must　no　longer　be　considered。　Suppose；　now；　that　neither　shoe…nails　nor　patches；　nor　other　clear　clews　can　be　proved　and　only　length　and　width　agree。　If　the　agreement　of　the　clews　were　really　a　substantiation　of　the　proof　by　evidence；　it　would　have　to　suffice　as　positive　evidence；　but　as　has　been　explained；　the　thing　proved　is　not　the　point　at　issue；　but　another　point。

The　negative　portion　of　the　evidence　will　naturally　be　developed　with　less　accuracy。　The　proof　is　limited　to　the　assertion　that　such　shoes　as　were　indicated　in　the　evidence　were　very　rarely　or　never　worn　in　that　region；　also　that　no　native　could　have　been　present　that　the　form　of　the　nails　allowed　inference　of　somebody　from　foreign　regions；　one　of　which　might　be　the　home　of　the　suspect；　etc。　Such　an　examination　shows　that　what　we　call　evidence　is　only　probability　or　possibility。

Another　form　which　seems　to　contradict　the　assertion　that　negative　proposi