euthydemus- 第1部分

Euthydemus
by　Plato
Translated　by　Benjamin　Jowett



INTRODUCTION。

The　Euthydemus；　though　apt　to　be　regarded　by　us　only　as　an　elaborate　jest；　has　also　a　very　serious　purpose。　　It　may　fairly　claim　to　be　the　oldest　treatise　on　logic；　for　that　science　originates　in　the　misunderstandings　which　necessarily　accompany　the　first　efforts　of　speculation。　　Several　of　the　fallacies　which　are　satirized　in　it　reappear　in　the　Sophistici　Elenchi　of　Aristotle　and　are　retained　at　the　end　of　our　manuals　of　logic。　　But　if　the　order　of　history　were　followed；　they　should　be　placed　not　at　the　end　but　at　the　beginning　of　them；　for　they　belong　to　the　age　in　which　the　human　mind　was　first　making　the　attempt　to　distinguish　thought　from　sense；　and　to　separate　the　universal　from　the　particular　or　individual。　　How　to　put　together　words　or　ideas；　how　to　escape　ambiguities　in　the　meaning　of　terms　or　in　the　structure　of　propositions；　how　to　resist　the　fixed　impression　of　an　'eternal　being'　or　'perpetual　flux；'　how　to　distinguish　between　words　and　thingsthese　were　problems　not　easy　of　solution　in　the　infancy　of　philosophy。　　They　presented　the　same　kind　of　difficulty　to　the　half…　educated　man　which　spelling　or　arithmetic　do　to　the　mind　of　a　child。　　It　was　long　before　the　new　world　of　ideas　which　had　been　sought　after　with　such　passionate　yearning　was　set　in　order　and　made　ready　for　use。　　To　us　the　fallacies　which　arise　in　the　pre…Socratic　philosophy　are　trivial　and　obsolete　because　we　are　no　longer　liable　to　fall　into　the　errors　which　are　expressed　by　them。　　The　intellectual　world　has　become　better　assured　to　us；　and　we　are　less　likely　to　be　imposed　upon　by　illusions　of　words。

The　logic　of　Aristotle　is　for　the　most　part　latent　in　the　dialogues　of　Plato。　　The　nature　of　definition　is　explained　not　by　rules　but　by　examples　in　the　Charmides；　Lysis；　Laches；　Protagoras；　Meno；　Euthyphro；　Theaetetus；　Gorgias；　Republic；　the　nature　of　division　is　likewise　illustrated　by　examples　in　the　Sophist　and　Statesman；　a　scheme　of　categories　is　found　in　the　Philebus；　the　true　doctrine　of　contradiction　is　taught；　and　the　fallacy　of　arguing　in　a　circle　is　exposed　in　the　Republic；　the　nature　of　synthesis　and　analysis　is　graphically　described　in　the　Phaedrus；　the　nature　of　words　is　analysed　in　the　Cratylus；　the　form　of　the　syllogism　is　indicated　in　the　genealogical　trees　of　the　Sophist　and　Statesman；　a　true　doctrine　of　predication　and　an　analysis　of　the　sentence　are　given　in　the　Sophist；　the　different　meanings　of　one　and　being　are　worked　out　in　the　Parmenides。　　Here　we　have　most　of　the　important　elements　of　logic；　not　yet　systematized　or　reduced　to　an　art　or　science；　but　scattered　up　and　down　as　they　would　naturally　occur　in　ordinary　discourse。　　They　are　of　little　or　no　use　or　significance　to　us；　but　because　we　have　grown　out　of　the　need　of　them　we　should　not　therefore　despise　them。　　They　are　still　interesting　and　instructive　for　the　light　which　they　shed　on　the　history　of　the　human　mind。

There　are　indeed　many　old　fallacies　which　linger　among　us；　and　new　ones　are　constantly　springing　up。　　But　they　are　not　of　the　kind　to　which　ancient　logic　can　be　usefully　applied。　　The　weapons　of　common　sense；　not　the　analytics　of　Aristotle；　are　needed　for　their　overthrow。　　Nor　is　the　use　of　the　Aristotelian　logic　any　longer　natural　to　us。　　We　no　longer　put　arguments　into　the　form　of　syllogisms　like　the　schoolmen；　the　simple　use　of　language　has　been；　happily；　restored　to　us。　　Neither　do　we　discuss　the　nature　of　the　proposition；　nor　extract　hidden　truths　from　the　copula；　nor　dispute　any　longer　about　nominalism　and　realism。　　We　do　not　confuse　the　form　with　the　matter　of　knowledge；　or　invent　laws　of　thought；　or　imagine　that　any　single　science　furnishes　a　principle　of　reasoning　to　all　the　rest。　　Neither　do　we　require　categories　or　heads　of　argument　to　be　invented　for　our　use。　　Those　who　have　no　knowledge　of　logic；　like　some　of　our　great　physical　philosophers；　seem　to　be　quite　as　good　reasoners　as　those　who　have。　　Most　of　the　ancient　puzzles　have　been　settled　on　the　basis　of　usage　and　common　sense；　there　is　no　need　to　reopen　them。　　No　science　should　raise　problems　or　invent　forms　of　thought　which　add　nothing　to　knowledge　and　are　of　no　use　in　assisting　the　acquisition　of　it。　　This　seems　to　be　the　natural　limit　of　logic　and　metaphysics；　if　they　give　us　a　more　comprehensive　or　a　more　definite　view　of　the　different　spheres　of　knowledge　they　are　to　be　studied；　if　not；　not。　　The　better　part　of　ancient　logic　appears　hardly　in　our　own　day　to　have　a　separate　existence；　it　is　absorbed　in　two　other　sciences：　　（1）　rhetoric；　if　indeed　this　ancient　art　be　not　also　fading　away　into　literary　criticism；　（2）　the　science　of　language；　under　which　all　questions　relating　to　words　and　propositions　and　the　combinations　of　them　may　properly　be　included。

To　continue　dead　or　imaginary　sciences；　which　make　no　signs　of　progress　and　have　no　definite　sphere；　tends　to　interfere　with　the　prosecution　of　living　ones。　　The　study　of　them　is　apt　to　blind　the　judgment　and　to　render　men　incapable　of　seeing　the　value　of　evidence；　and　even　of　appreciating　the　nature　of　truth。　　Nor　should　we　allow　the　living　science　to　become　confused　with　the　dead　by　an　ambiguity　of　language。　　The　term　logic　has　two　different　meanings；　an　ancient　and　a　modern　one；　and　we　vainly　try　to　bridge　the　gulf　between　them。　　Many　perplexities　are　avoided　by　keeping　them　apart。　　There　might　certainly　be　a　new　science　of　logic；　it　would　not　however　be　built　up　out　of　the　fragments　of　the　old；　but　would　be　distinct　from　themrelative　to　the　state　of　knowledge　which　exists　at　the　present　time；　and　based　chiefly　on　the　methods　of　Modern　Inductive　philosophy。　　Such　a　science　might　have　two　legitimate　fields：　　first；　the　refutation　and　explanation　of　false　philosophies　still　hovering　in　the　air　as　they　appear　from　the　point　of　view　of　later　experience　or　are　comprehended　in　the　history　of　the　human　mind；　as　in　a　larger　horizon：　　secondly；　it　might　furnish　new　forms　of　thought　more　adequate　to　the　expression　of　all　the　diversities　and　oppositions　of　knowledge　which　have　grown　up　in　these　latter　days；　it　might　also　suggest　new　methods　of　enquiry　derived　from　the　comparison　of　the　sciences。　　Few　will　deny　that　the　introduction　of　the　words　'subject'　and　'object'　and　the　Hegelian　reconciliation　of　opposites　have　been　'most　gracious　aids'　to　psychology；　or　that　the　methods　of　Bacon　and　Mill　have　shed　a　light　far　and　wide　on　the　realms　of　knowledge。　　These　two　great　studies；　the　one　destructive　and　corrective　of　error；　the　other　conservative　and　constructive　of　truth；　might　be　a　first　and　second　part　of　logic。　　Ancient　logic　would　be　the　propaedeutic　or　gate　of　approach　to　logical　science；nothing　more。　　But　to　pursue　such　speculations　further；　though　not　irrelevant；　might　lead　us　too　far　away　from　the　argument　of　the　dialogue。

The　Euthydemus　is；　of　all　the　Dialogues　of　Plato；　that　in　which　he　approaches　most　nearly　to　the　comic　poet。　　The　mirth　is　broader；　the　irony　more　sustained；　the　contrast　between　Socrates　and　the　two　Sophists；　although　veiled；　penetrates　deeper　than　in　any　other　of　his　writings。　　Even　Thrasymachus；　in　the　Republic；　is　at　last　pacified；　and　becomes　a　friendly　and　interested　auditor　of　the　great　discourse。　　But　in　the　Euthydemus　the　mask　is　never　dropped；　the　accustomed　irony　of　Socrates　continues　to　the　end。。。

Socrates　narrates　to　Crito　a　remarkable　scene　in　which　he　has　himself　taken　part；　and　in　which　the　two　brothers；　Dionysodorus　and　Euthydemus；　are　the　chief　performers。　　They　are　natives　of　Chios；　who　had　settled　at　Thurii；　but　were　driven　out；　and　in　former　days　had　been　known　at　Athens　as　professors　of　rhetoric　and　of　the　art　of　fighting　in　armour。　　To　this　they　have　now　added　a　new　accomplishmentthe　art　of　Eristic；　or　fighting　with　words；　which　they　are　likewise　willing　to　teach　'for　a　consideration。'　　But　they　can　also　teach　virtue　in　a　very　short　time　and　in　the　very　best　manner。　　Socrates；　who　is　always　on　the　look…out　for　teachers　of　virtue；　is　interested　in　the　youth　Cleinias；　the　grandson　of　the　great　Alcibiades；　and　is　desirous　that　he　should　have　the　benefit　of　their　instructions。　　He　is　ready　to　fall　down　and　worship　them；　although　the　greatness　of　their　professions　does　arouse　in　his　mind　a　temporary　incredulity。

A　circle　gathers　round　them；　in　the　midst　of　which　are　Socrates；　the　two　brothers；　the　youth　Cleinias；　who　is　watched　by　the　eager　eyes　of　his　lover　Ctesippus；　and　others。　　The　performance　begins；　and　such　a　performance　as　might　well　seem　to　require　an　invocation　of　Memory　and　the　Muses。　　It　is　agreed　that　the　brothers　shall　question　Cleinias。　　'Cleinias；'　says　Euthydemus；　'who　learn；　the　wise　or　the　unwise？'　　'The　wise；'　is　the　reply；　given　with　blushing　and　hesitation。　　'And　yet　when　you　learned　you　did　not　know　and　were　not　wise。'　　Then　Dionysodorus　takes　up　the　ball：　　'Who　are　they　who　learn　dictation　of　the　grammar…master；　the　wise　or　the　foolish　boys？'　　'The　wise。'　　'Then；　after　all；　the　wise　learn。'　　'And　do　they　learn；'　said　Euthydemus；　'what　they　know　or　what　they　do　not　know？'　　'The　latter。'　　'And　dictation　is　a　dictation　of　letters？'　　'Yes。'　　'And　you　know　letters？'　　'Yes。'　　'Then　you　learn　what　you　know。'　　'But；