Str。　The　one　may　be　compared　to　disease　in　the　body；　the　other　to
  deformity。
  Theaet。　I　do　not　understand。
  Str。　Perhaps　you　have　never　reflected　that　disease　and　discord　are
  the　same。
  Theaet。　To　this；　again；　I　know　not　what　I　should　reply。
  Str。　Do　you　not　conceive　discord　to　be　a　dissolution　of　kindred
  clements；　originating　in　some　disagreement？
  Theaet。　Just　that。
  Str。　And　is　deformity　anything　but　the　want　of　measure；　which　is
  always　unsightly？
  Theaet。　Exactly。
  Str。　And　do　we　not　see　that　opinion　is　opposed　to　desire；　pleasure
  to　anger；　reason　to　pain；　and　that　all　these　elements　are　opposed　to
  one　another　in　the　souls　of　bad　men？
  Theaet。　Certainly。
  Str。　And　yet　they　must　all　be　akin？
  Theaet。　Of　course。
  Str。　Then　we　shall　be　right　in　calling　vice　a　discord　and
  disease　of
  the　soul？
  Theaet。　Most　true。
  Str。　And　when　things　having　motion；　an　aiming　at　an　appointed
  mark；　continually　miss　their　aim　and　glance　aside；　shall　we　say　that
  this　is　the　effect　of　symmetry　among　them；　or　of　the　want　of
  symmetry？
  Theaet。　Clearly　of　the　want　of　symmetry。
  Str。　But　surely　we　know　that　no　soul　is　voluntarily　ignorant　of
  anything？
  Theaet。　Certainly　not。
  Str。　And　what　is　ignorance　but　the　aberration　of　a　mind　which　is
  bent　on　truth；　and　in　which　the　process　of　understanding　is
  perverted？
  Theaet。　True。
  Str。　Then　we　are　to　regard　an　unintelligent　soul　as　deformed　and
  devoid　of　symmetry？
  Theaet。　Very　true。
  Str。　Then　there　are　these　two　kinds　of　evil　in　the　soul…the　one
  which　is　generally　called　vice；　and　is　obviously　a　disease　of　the
  soul。。。
  Theaet。　Yes。
  Str。　And　there　is　the　other；　which　they　call　ignorance；　and　which；
  because　existing　only　in　the　soul；　they　will　not　allow　to　be　vice。
  Theaet。　I　certainly　admit　what　I　at　first　disputed…that　there　are
  two　kinds　of　vice　in　the　soul；　and　that　we　ought　to　consider
  cowardice；　intemperance；　and　injustice　to　be　alike　forms　of
  disease　in
  the　soul；　and　ignorance；　of　which　there　are　all　sorts　of
  varieties；　to
  be　deformity。
  Str。　And　in　the　case　of　the　body　are　there　not　two　arts；　which
  have　to　do　with　the　two　bodily　states？
  Theaet。　What　are　they？
  Str。　There　is　gymnastic；　which　has　to　do　with　deformity；　and
  medicine；　which　has　to　do　with　disease。
  Theaet。　True。
  Str。　And　where　there　is　insolence　and　injustice　and　cowardice；　is
  not　chastisement　the　art　which　is　most　required？
  Theaet。　That　certainly　appears　to　be　the　opinion　of　mankind。
  Str。　Again；　of　the　various　kinds　of　ignorance；　may　not　instruction
  be　rightly　said　to　be　the　remedy？
  Theaet。　True。
  Str。　And　of　the　art　of　instruction；　shall　we　say　that　there　is　one
  or　many　kinds？　At　any　rate　there　are　two　principal　ones。　Think。
  Theaet。　I　will。
  Str。　I　believe　that　I　can　see　how　we　shall　soonest　arrive　at　the
  answer　to　this　question。
  Theaet。　How？
  Str。　If　we　can　discover　a　line　which　divides　ignorance　into　two
  halves。　For　a　division　of　ignorance　into　two　parts　will　certainly
  imply　that　the　art　of　instruction　is　also　twofold；　answering　to　the
  two　divisions　of　ignorance。
  Theaet。　Well；　and　do　you　see　what　you　are　looking　for？
  Str。　I　do　seem　to　myself　to　see　one　very　large　and　bad　sort　of
  ignorance　which　is　quite　separate；　and　may　be　weighed　in　the　scale
  against　all　other　sorts　of　ignorance　put　together。
  Theaet。　What　is　it？
  Str。　When　a　person　supposes　that　he　knows；　and　does　not　know　this
  appears　to　be　the　great　source　of　all　the　errors　of　the　intellect。
  Theaet。　True。
  Str。　And　this；　if　I　am　not　mistaken；　is　the　kind　of　ignorance
  which　specially　earns　the　title　of　stupidity。
  Theaet。　True。
  Str。　What　name；　then；　shall　be　given　to　the　sort　of　instruction
  which　gets　rid　of　this？
  Theaet。　The　instruction　which　you　mean；　Stranger；　is；　I　should
  imagine；　not　the　teaching　of　handicraft　arts；　but　what；　thanks　to
  us；　has　been　termed　education　in　this　part　the　world。
  Str。　Yes；　Theaetetus；　and　by　nearly　all　Hellenes。　But　we　have
  still　to　consider　whether　education　admits　of　any　further　division。
  Theaet。　We　have。
  Str。　I　think　that　there　is　a　point　at　which　such　a　division　is
  possible。
  Theaet。　Where？
  Str。　Of　education；　one　method　appears　to　be　rougher；　and　another
  smoother。
  Theaet。　How　are　we　to　distinguish　the　two？
  Str。　There　is　the　time…honoured　mode　which　our　fathers　commonly
  practised　towards　their　sons；　and　which　is　still　adopted　by
  many…either　of　roughly　reproving　their　errors；　or　of　gently　advising
  them；　which　varieties　may　be　correctly　included　under　the
  general　term
  of　admonition。
  Theaet。　True。
  Str。　But　whereas　some　appear　to　have　arrived　at　the　conclusion
  that　all　ignorance　is　involuntary；　and　that　no　one　who　thinks
  himself　wise　is　willing　to　learn　any　of　those　things　in　which　he　is
  conscious　of　his　own　cleverness；　and　that　the　admonitory　sort　of
  instruction　gives　much　trouble　and　does　little　good…
  Theaet。　There　they　are　quite　right。
  Str。　Accordingly；　they　set　to　work　to　eradicate　the　spirit　of
  conceit　in　another　way。
  Theaet。　In　what　way？
  Str。　They　cross…examine　a　man's　words；　when　he　thinks　that　he　is
  saying　something　and　is　really　saying　nothing；　and　easily　convict
  him　of　inconsistencies　in　his　opinions；　these　they　then
  collect　by　the
  dialectical　process；　and　placing　them　side　by　side；　show　that　they
  contradict　one　another　about　the　same　things；　in　relation　to　the
  same　things；　and　in　the　same　respect。　He；　seeing　this；　is　angry　with
  himself；　and　grows　gentle　towards　others；　and　thus　is　entirely
  delivered　from　great　prejudices　and　harsh　notions；　in　a　way　which　is
  most　amusing　to　the　hearer；　and　produces　the　most　lasting　good
  effect　on　the　person　who　is　the　subject　of　the　operation。　For　as　the
  physician　considers　that　the　body　will　receive　no　benefit　from
  taking　food　until　the　internal　obstacles　have　been　removed；　so　the
  purifier　of　the　soul　is　conscious　that　his　patient　will　receive　no
  benefit　from　the　application　of　knowledge　until　he　is　refuted；　and
  from　refutation　learns　modesty；　he　must　be　purged　of　his　prejudices
  first　and　made　to　think　that　he　knows　only　what　he　knows；
  and　no　more。
  Theaet。　That　is　certainly　the　best　and　wisest　state　of　mind。
  Str。　For　all　these　reasons；　Theaetetus；　we　must　admit　that
  refutation　is　the　greatest　and　chiefest　of　purifications；　and　he　who
  has　not　been　refuted；　though　he　be　the　Great　King　himself；　is　in　an
  awful　state　of　impurity；　he　is　uninstructed　and　deformed　in　those
  things　in　which　he　who　would　be　truly　blessed　ought　to　be　fairest
  and　purest。
  Theaet。　Very　true。
  Str。　And　who　are　the　ministers　of　this　art？
  I　am　afraid　to　say　the　Sophists。
  Theaet。　Why？
  Str。　Lest　we　should　assign　to　them　too　high　a　prerogative。
  Theaet。　Yet　the　Sophist　has　a　certain　likeness　to　our　minister　of
  purification。
  Str。　Yes；　the　same　sort　of　likeness　which　a　wolf；　who　is　the
  fiercest　of　animals；　has　to　a　dog；　who　is　the　gentlest。　But　he　who
  would　not　be　found　tripping；　ought　to　be　very　careful　in　this　matter
  of　comparisons；　for　they　are　most　slippery　things。　Nevertheless；　let
  us　assume　that　the　Sophists　are　the　men。　I　say　this
  provisionally；　for
  I　think　that　the　line　which　divides　them　will　be　marked　enough　if
  proper　care　is　taken。
  Theaet。　Likely　enough。
  Str。　Let　us　grant；　then；　that　from　the　discerning　art　comes
  purification；　and　from　purification　let　there　be　separated　off　a
  part　which　is　concerned　with　the　soul；　of　this　mental　purification
  instruction　is　a　portion；　and　of　instruction　education；　and　of
  education；　that　refutation　of　vain　conceit　which　has　been　discovered
  in　the　present　argument；　and　let　this　be　called　by　you　and　me　the
  nobly…descended　art　of　Sophistry。
  Theaet。　Very　well；　and　yet；　considering　the　number　of
  forms　in　which
  he　has　presented　himself；　I　begin　to　doubt　how　I　can　with
  any　truth　or
  confidence　describe　the　real　nature　of　the　Sophist。
  Str。　You　naturally　feel　perplexed；　and　yet　I　think　that　he　must　be
  still　more　perplexed　in　his　attempt　to　escape　us；　for　as　the　proverb
  says；　when　every　way　is　blocked；　there　is　no　escape；　now；
  then；　is　the
  time　of　all　others　to　set　upon　him。
  Theaet。　True。
  Str。　First　let　us　wait　a　moment　and　recover　breath；　and
  while　we　are
  resting；　we　may　reckon　up　in　how　many　forms　he　has　appeared。　In　the
  first　place；　he　was　discovered　to　be　a　paid　hunter　after　wealth　and
  youth。
  Theaet。　Yes。
  Str。　In　the　second　place；　he　was　a　merchant　in　the　goods　of　the
  soul。
  Theaet。　Certainly。
  Str。　In　the　third　place；　he　has　turned　out　to　be　a　retailer　of　the
  same　sort　of　wares。
  Theaet。　Yes；　and　in　the　fourth　place；　he　himself　manufactured　the
  learned　wares　which　he　sold。
  Str。　Quite　right；　I　will　try　and　remember　the　fifth　myself。　He
  belonged　to　the　fighting　class；　and　was　further　distinguished　as　a
  hero　of　debate；　who　professed　the　eristic　art。
  Theaet。　True。
  Str。　The　sixth　point　was　doubtful；　and　yet　we　at　last
  agreed　that　he
  was　a　purger　of　souls；　who　cleared　away　notions　obstructive　to
  knowledge。
  Th