useful；　not　to　say　indispensable；　to　well…being　that　it　is　as　much　the
  duty　of　governments　to　uphold　those　beliefs；　as　to　protect　any　other
  of　the　interests　of　society。　In　a　case　of　such　necessity；　and　so
  directly　in　the　line　of　their　duty；　something　less　than
  infallibility　may；　it　is　maintained；　warrant；　and　even　bind；
  governments　to　act　on　their　own　opinion；　confirmed　by　the　general
  opinion　of　mankind。　It　is　also　often　argued；　and　still　oftener
  thought；　that　none　but　bad　men　would　desire　to　weaken　these　salutary
  beliefs；　and　there　can　be　nothing　wrong；　it　is　thought；　in　restraining
  bad　men；　and　prohibiting　what　only　such　men　would　wish　to　practise。
  This　mode　of　thinking　makes　the　justification　of　restraints　on
  discussion　not　a　question　of　the　truth　of　doctrines；　but　of　their
  usefulness；　and　flatters　itself　by　that　means　to　escape　the
  responsibility　of　claiming　to　be　an　infallible　judge　of　opinions。
  But　those　who　thus　satisfy　themselves；　do　not　perceive　that　the
  assumption　of　infallibility　is　merely　shifted　from　one　point　to
  another。　The　usefulness　of　an　opinion　is　itself　matter　of　opinion：
  as　disputable；　as　open　to　discussion；　and　requiring　discussion　as　much
  as　the　opinion　itself。　There　is　the　same　need　of　an　infallible　judge
  of　opinions　to　decide　an　opinion　to　be　noxious；　as　to　decide　it　to
  be　false；　unless　the　opinion　condemned　has　full　opportunity　of
  defending　itself。　And　it　will　not　do　to　say　that　the　heretic　may　be
  allowed　to　maintain　the　utility　or　harmlessness　of　his　opinion；　though
  forbidden　to　maintain　its　truth。　The　truth　of　an　opinion　is　part　of
  its　utility。　If　we　would　know　whether　or　not　it　is　desirable　that　a
  proposition　should　be　believed；　is　it　possible　to　exclude　the
  consideration　of　whether　or　not　it　is　true？　In　the　opinion；　not　of　bad
  men；　but　of　the　best　men；　no　belief　which　is　contrary　to　truth　can
  be　really　useful：　and　can　you　prevent　such　men　from　urging　that
  plea；　when　they　are　charged　with　culpability　for　denying　some　doctrine
  which　they　are　told　is　useful；　but　which　they　believe　to　be　false？
  Those　who　are　on　the　side　of　received　opinions　never　fail　to　take
  all　possible　advantage　of　this　plea；　you　do　not　find　them　handling　the
  question　of　utility　as　if　it　could　be　completely　abstracted　from
  that　of　truth：　on　the　contrary；　it　is；　above　all；　because　their
  doctrine　is　〃the　truth；〃　that　the　knowledge　or　the　belief　of　it　is
  held　to　be　so　indispensable。　There　can　be　no　fair　discussion　of　the
  question　of　usefulness　when　an　argument　so　vital　may　be　employed　on
  one　side；　but　not　on　the　other。　And　in　point　of　fact；　when　law　or
  public　feeling　do　not　permit　the　truth　of　an　opinion　to　be　disputed；
  they　are　just　as　little　tolerant　of　a　denial　of　its　usefulness。　The
  utmost　they　allow　is　an　extenuation　of　its　absolute　necessity；　or　of
  the　positive　guilt　of　rejecting　it。
  In　order　more　fully　to　illustrate　the　mischief　of　denying　a
  hearing　to　opinions　because　we；　in　our　own　judgment；　have　condemned
  them；　it　will　be　desirable　to　fix　down　the　discussion　to　a　concrete
  case；　and　I　choose；　by　preference；　the　cases　which　are　least
  favourable　to　me…　in　which　the　argument　against　freedom　of　opinion；
  both　on　the　score　of　truth　and　on　that　of　utility；　is　considered　the
  strongest。　Let　the　opinions　impugned　be　the　belief　in　a　God　and　in　a
  future　state；　or　any　of　the　commonly　received　doctrines　of　morality。
  To　fight　the　battle　on　such　ground　gives　a　great　advantage　to　an
  unfair　antagonist；　since　he　will　be　sure　to　say　（and　many　who　have
  no　desire　to　be　unfair　will　say　it　internally）；　Are　these　the
  doctrines　which　you　do　not　deem　sufficiently　certain　to　be　taken　under
  the　protection　of　law？　Is　the　belief　in　a　God　one　of　the　opinions　to
  feel　sure　of　which　you　hold　to　be　assuming　infallibility？　But　I　must
  be　permitted　to　observe；　that　it　is　not　the　feeling　sure　of　a　doctrine
  （be　it　what　it　may）　which　I　call　an　assumption　of　infallibility。　It　is
  the　undertaking　to　decide　that　question　for　others；　without　allowing
  them　to　hear　what　can　be　said　on　the　contrary　side。　And　I　denounce　and
  reprobate　this　pretension　not　the　less；　if　put　forth　on　the　side　of　my
  most　solemn　convictions。　However　positive　any　one's　persuasion　may　be；
  not　only　of　the　falsity　but　of　the　pernicious　consequences…　not　only
  of　the　pernicious　consequences；　but　（to　adopt　expressions　which　I
  altogether　condemn）　the　immorality　and　impiety　of　an　opinion；　yet
  if；　in　pursuance　of　that　private　judgment；　though　backed　by　the　public
  judgment　of　his　country　or　his　contemporaries；　he　prevents　the　opinion
  from　being　heard　in　its　defence；　he　assumes　infallibility。　And　so
  far　from　the　assumption　being　less　objectionable　or　less　dangerous
  because　the　opinion　is　called　immoral　or　impious；　this　is　the　case
  of　all　others　in　which　it　is　most　fatal。　These　are　exactly　the
  occasions　on　which　the　men　of　one　generation　commit　those　dreadful
  mistakes　which　excite　the　astonishment　and　horror　of　posterity。　It
  is　among　such　that　we　find　the　instances　memorable　in　history；　when
  the　arm　of　the　law　has　been　employed　to　root　out　the　best　men　and
  the　noblest　doctrines；　with　deplorable　success　as　to　the　men；　though
  some　of　the　doctrines　have　survived　to　be　（as　if　in　mockery）　invoked
  in　defence　of　similar　conduct　towards　those　who　dissent　from　them；
  or　from　their　received　interpretation。
  Mankind　can　hardly　be　too　often　reminded；　that　there　was　once　a
  man　named　Socrates；　between　whom　and　the　legal　authorities　and
  public　opinion　of　his　time　there　took　place　a　memorable　collision。
  Born　in　an　age　and　country　abounding　in　individual　greatness；　this　man
  has　been　handed　down　to　us　by　those　who　best　knew　both　him　and　the
  age；　as　the　most　virtuous　man　in　it；　while　we　know　him　as　the　head　and
  prototype　of　all　subsequent　teachers　of　virtue；　the　source　equally
  of　the　lofty　inspiration　of　Plato　and　the　judicious　utilitarianism
  of　Aristotle；　〃i　mastri　di　color　che　sanno；〃　the　two　headsprings　of
  ethical　as　of　all　other　philosophy。　This　acknowledged　master　of　all
  the　eminent　thinkers　who　have　since　lived…　whose　fame；　still　growing
  after　more　than　two　thousand　years；　all　but　outweighs　the　whole
  remainder　of　the　names　which　make　his　native　city　illustrious…　was
  put　to　death　by　his　countrymen；　after　a　judicial　conviction；　for
  impiety　and　immorality。　Impiety；　in　denying　the　gods　recognised　by　the
  State；　indeed　his　accuser　asserted　（see　the　Apologia）　that　he　believed
  in　no　gods　at　all。　Immorality；　in　being；　by　his　doctrines　and
  instructions；　a　〃corruptor　of　youth。〃　Of　these　charges　the　tribunal；
  there　is　every　ground　for　believing；　honestly　found　him　guilty；　and
  condemned　the　man　who　probably　of　all　then　born　had　deserved　best　of
  mankind　to　be　put　to　death　as　a　criminal。
  To　pass　from　this　to　the　only　other　instance　of　judicial　iniquity；
  the　mention　of　which；　after　the　condemnation　of　Socrates；　would　not　be
  an　anti…climax：　the　event　which　took　place　on　Calvary　rather　more　than
  eighteen　hundred　years　ago。　The　man　who　left　on　the　memory　of　those
  who　witnessed　his　life　and　conversation　such　an　impression　of　his
  moral　grandeur　that　eighteen　subsequent　centuries　have　done　homage
  to　him　as　the　Almighty　in　person；　was　ignominiously　put　to　death；　as
  what？　As　a　blasphemer。　Men　did　not　merely　mistake　their　benefactor；
  they　mistook　him　for　the　exact　contrary　of　what　he　was；　and　treated
  him　as　that　prodigy　of　impiety　which　they　themselves　are　now　held　to
  be　for　their　treatment　of　him。　The　feelings　with　which　mankind　now
  regard　these　lamentable　transactions；　especially　the　later　of　the　two；
  render　them　extremely　unjust　in　their　judgment　of　the　unhappy
  actors。　These　were；　to　all　appearance；　not　bad　men…　not　worse　than
  men　commonly　are；　but　rather　the　contrary；　men　who　possessed　in　a
  full；　or　somewhat　more　than　a　full　measure；　the　religious；　moral；
  and　patriotic　feelings　of　their　time　and　people：　the　very　kind　of
  men　who；　in　all　times；　our　own　included；　have　every　chance　of
  passing　through　life　blameless　and　respected。　The　high…priest　who　rent
  his　garments　when　the　words　were　pronounced；　which；　according　to　all
  the　ideas　of　his　country；　constituted　the　blackest　guilt；　was　in　all
  probability　quite　as　sincere　in　his　horror　and　indignation　as　the
  generality　of　respectable　and　pious　men　now　are　in　the　religious　and
  moral　sentiments　they　profess；　and　most　of　those　who　now　shudder　at
  his　conduct；　if　they　had　lived　in　his　time；　and　been　born　Jews；
  would　have　acted　precisely　as　he　did。　Orthodox　Christians　who　are
  tempted　to　think　that　those　who　stoned　to　death　the　first　martyrs　must
  have　been　worse　men　than　they　themselves　are；　ought　to　remember　that
  one　of　those　persecutors　was　Saint　Paul。
  Let　us　add　one　more