and　sold　in　another…wares　of　the　soul　which　are　hawked　about　either
  for　the　sake　of　instruction　or　amusement；…may　not　he　who　takes　them
  about　and　sells　them　be　quite　as　truly　called　a　merchant　as　he　who
  sells　meats　and　drinks？
  Theaet。　To　be　sure　he　may。
  Str。　And　would　you　not　call　by　the　same　name　him　who　buys　up
  knowledge　and　goes　about　from　city　to　city　exchanging　his　wares　for
  money？
  Theaet。　Certainly　I　should。
  Str。　Of　this　merchandise　of　the　soul；　may　not　one　part　be　fairly
  termed　the　art　of　display？　And　there　is　another　part　which　is
  certainly　not　less　ridiculous；　but　being　a　trade　in　learning　must　be
  called　by　some　name　germane　to　the　matter？
  Theaet。　Certainly。
  Str。　The　latter　should　have　two　names；…one　descriptive　of　the　sale
  of　the　knowledge　of　virtue；　and　the　other　of　the　sale　of　other　kinds
  of　knowledge。
  Theaet。　Of　course。
  Str。　The　name　of　art…seller　corresponds　well　enough　to　the　latter；
  but　you　must　try　and　tell　me　the　name　of　the　other。
  Theaet。　He　must　be　the　Sophist；　whom　we　are　seeking；　no　other　name
  can　possibly　be　right。
  Str。　No　other；　and　so　this　trader　in　virtue　again　turns　out　to　be
  our　friend　the　Sophist；　whose　art　may　now　be　traced　from　the　art　of
  acquisition　through　exchange；　trade；　merchandise；　to　a　merchandise
  of　the　soul　which　is　concerned　with　speech　and　the　knowledge　of
  virtue。
  Theaet。　Quite　true。
  Str。　And　there　may　be　a　third　reappearance　of　him；…for　he　may　have
  settled　down　in　a　city；　and　may　fabricate　as　well　as　buy　these　same
  wares；　intending　to　live　by　selling　them；　and　he　would　still
  be　called
  a　Sophist？
  Theaet。　Certainly。
  Str。　Then　that　part　of　acquisitive　art　which　exchanges；　and　of
  exchange　which　either　sells　a　man's　own　productions　or　retails　those
  of　others；　as　the　case　may　be；　and　in　either　way　sells　the　knowledge
  of　virtue；　you　would　again　term　Sophistry？
  Theaet。　I　must；　if　I　am　to　keep　pace　with　the　argument。
  Str。　Let　us　consider　once　more　whether　there　may　not　be　yet
  another　aspect　of　sophistry。
  Theaet。　What　is　it？
  Str。　In　the　acquisitive　there　was　a　subdivision　of　the　combative
  or　fighting　art。
  Theaet。　There　was。
  Str。　Perhaps　we　had　better　divide　it。
  Theaet。　What　shall　be　the　divisions？
  Str。　There　shall　be　one　division　of　the　competitive；　and　another
  of　the　pugnacious。
  Theaet。　Very　good。
  Str。　That　part　of　the　pugnacious　which　is　contest　of
  bodily　strength
  may　be　properly　called　by　some　such　name　as　violent。
  Theaet。　True。
  Str。　And　when　the　war　is　one　of　words；　it　may　be　termed
  controversy？
  Theaet。　Yes。
  Str。　And　controversy　may　be　of　two　kinds。
  Theaet。　What　are　they？
  Str。　When　long　speeches　are　answered　by　long　speeches；　and　there
  is　public　discussion　about　the　just　and　unjust；　that　is　forensic
  controversy。
  Theaet。　Yes。
  Str。　And　there　is　a　private　sort　of　controversy；　which　is　cut　up
  into　questions　and　answers；　and　this　is　commonly　called　disputation？
  Theaet。　Yes；　that　is　the　name。
  Str。　And　of　disputation；　that　sort　which　is　only　a　discussion
  about　contracts；　and　is　carried　on　at　random；　and　without　rules…art；
  is　recognized　by　the　reasoning　faculty　to　be　a　distinct
  class；　but　has
  hitherto　had　no　distinctive　name；　and　does　not　deserve　to　receive
  one　from　us。
  Theaet。　No；　for　the　different　sorts　of　it　are　too　minute　and
  heterogeneous。
  Str。　But　that　which　proceeds　by　rules　of　art　to　dispute　about
  justice　and　injustice　in　their　own　nature；　and　about　things　in
  general；　we　have　been　accustomed　to　call　argumentation　（Eristic）？
  Theaet。　Certainly。
  Str。　And　of　argumentation；　one　sort　wastes　money；　and　the　other
  makes　money。
  Theaet。　Very　true。
  Str。　Suppose　we　try　and　give　to　each　of　these　two　classes　a　name。
  Theaet。　Let　us　do　so。
  Str。　I　should　say　that　the　habit　which　leads　a　man　to　neglect　his
  own　affairs　for　the　pleasure　of　conversation；　of　which　the　style　is
  far　from　being　agreeable　to　the　majority　of　his　hearers；　may
  be　fairly
  termed　loquacity：　such　is　my　opinion。
  Theaet。　That　is　the　common　name　for　it。
  Str。　But　now　who　the　other　is；　who　makes　money　out　of　private
  disputation；　it　is　your　turn　to　say。
  Theaet。　There　is　only　one　true　answer：　he　is　the　wonderful
  Sophist；　of　whom　we　are　in　pursuit；　and　who　reappears　again　for　the
  fourth　time。
  Str。　Yes；　and　with　a　fresh　pedigree；　for　he　is　the　money…making
  species　of　the　Eristic；　disputatious；　controversial。　pugnacious；
  combative；　acquisitive　family；　as　the　argument　has　already　proven。
  Theaet。　Certainly。
  Str。　How　true　was　the　observation　that　he　was　a　many…sided　animal；
  and　not　to　be　caught　with　one　hand；　as　they　say！
  Theaet。　Then　you　must　catch　him　with　two。
  Str。　Yes；　we　must；　if　we　can。　And　therefore　let　us　try；　another
  track　in　our　pursuit　of　him：　You　are　aware　that　there　are　certain
  menial　occupations　which　have　names　among　servants？
  Theaet。　Yes；　there　are　many　such；　which　of　them　do　you　mean？
  Str。　I　mean　such　as　sifting；　straining；　winnowing；　threshing。
  Theaet。　Certainly。
  Str。　And　besides　these　there　are　a　great　many　more；　such
  as　carding；
  spinning；　adjusting　the　warp　and　the　woof；　and　thousands　of　similar
  expressions　are　used　in　the　arts。
  Theaet。　Of　what　are　they　to　be　patterns；　and　what　are　we
  going　to　do
  with　them　all？
  Str。　I　think　that　in　all　of　these　there　is　implied　a　notion　of
  division。
  Theaet。　Yes。
  Str。　Then　if；　as　I　was　saying；　there　is　one　art　which　includes　all
  of　them；　ought　not　that　art　to　have　one　name？
  Theaes。　And　what　is　the　name　of　the　art？
  Str。　The　art　of　discerning　or　discriminating。
  Theaet。　Very　good。
  Str。　Think　whether　you　cannot　divide　this。
  Theaet。　I　should　have　to　think　a　long　while。
  Str。　In　all　the　previously　named　processes　either　like　has　been
  separated　from　like　or　the　better　from　the　worse。
  Theaet。　I　see　now　what　you　mean。
  Str；　There　is　no　name　for　the　first　kind　of　separation；　of　the
  second；　which　throws　away　the　worse　and　preserves　the　better；　I　do
  know　a　name。
  Theaet。　What　is　it？
  Str。　Every　discernment　or　discrimination　of　that　kind；　as　I　have
  observed；　is　called　a　purification。
  Theaet。　Yes；　that　is　the　usual　expression。
  Str。　And　any　one　may　see　that　purification　is　of　two　kinds。
  Theaet。　Perhaps　so；　if　he　were　allowed　time　to　think；　but　I　do　not
  see　at　this　moment。
  Str。　There　are　many　purifications　of　bodies　which　may　with
  propriety
  be　comprehended　under　a　single　name。
  Theaet。　What　are　they；　and　what　is　their　name？
  Str。　There　is　the　purification　of　living　bodies　in　their　inward
  and　in　their　outward　parts；　of　which　the　former　is　duly　effected　by
  medicine　and　gymnastic；　the　latter　by　the　not　very　dignified　art　of
  the　bath…man；　and　there　is　the　purification　of　inanimate
  substances…to
  this　the　arts　of　fulling　and　of　furbishing　in　general　attend　in　a
  number　of　minute　particulars；　having　a　variety　of　names　which　are
  thought　ridiculous。
  Theaet。　Very　true。
  Str。　There　can　be　no　doubt　that　they　are　thought　ridiculous；
  Theaetetus；　but　then　the　dialectical　art　never　considers　whether　the
  benefit　to　be　derived　from　the　purge　is　greater　or　less　than　that　to
  be　derived　from　the　sponge；　and　has　not　more　interest　in　the　one
  than　in　the　other；　her　endeavour　is　to　know　what　is　and　is
  not　kindred
  in　all　arts；　with　a　view　to　the　acquisition　of　intelligence；　and
  having　this　in　view；　she　honours　them　all　alike；　and　when　she　makes
  comparisons；　she　counts　one　of　them　not　a　whit　more　ridiculous　than
  another；　nor　does　she　esteem　him　who　adduces　as　his　example　of
  hunting；　the　general's　art；　at　all　more　decorous　than　another　who
  cites　that　of　the　vermin…destroyer；　but　only　as　the　greater
  pretender　of　the　two。　And　as　to　your　question　concerning　the　name
  which　was　to　comprehend　all　these　arts　of　purification；　whether　of
  animate　or　inanimate　bodies；　the　art　of　dialectic　is　in　no　wise
  particular　about　fine　words；　if　she　maybe　only　allowed　to　have　a
  general　name　for　all　other　purifications；　binding　them　up
  together　and
  separating　them　off　from　the　purification　of　the　soul　or　intellect。
  For　this　is　the　purification　at　which　she　wants　to　arrive；
  and　this　we
  should　understand　to　be　her　aim。
  Theaet。　Yes；　I　understand；　and　I　agree　that　there　are　two　sorts　of
  purification　and　that　one　of　them　is　concerned　with　the
  soul；　and　that
  there　is　another　which　is　concerned　with　the　body。
  Str。　Excellent；　and　now　listen　to　what　I　am　going　to　say；
  and　try　to
  divide　further　the　first　of　the　two。
  Theaet。　Whatever　line　of　division　you　suggest；　I　will　endeavour　to
  assist　you。
  Str。　Do　we　admit　that　virtue　is　distinct　from　vice　in　the　soul？
  Theaet。　Certainly。
  Str。　And　purification　was　to　leave　the　good　and　to　cast
  out　whatever
  is　bad？
  Theaet。　True。
  Str。　Then　any　taking　away　of　evil　from　the　soul　may　be　properly
  called　purification？
  Theaet。　Yes。
  Str。　And　in　the　soul　there　are　two　kinds　of　evil。
  Theaet。　What　are　they？
  Str。　The　one　may　be　compared　to　disease　in　the　body；　the　other　to
  deformity。
  Theaet。　I　do　not　und