of　reason　directed　to　objects　of　our　possible　volition　generally；　as
  in　the　principle　of　perfection；　in　either　case　the　will　never
  determines　itself　immediately　by　the　conception　of　the　action；　but
  only　by　the　influence　which　the　foreseen　effect　of　the　action　has　on
  the　will；　I　ought　to　do　something；　on　this　account；　because　I　wish　for
  something　else；　and　here　there　must　be　yet　another　law　assumed　in　me
  as　its　subject；　by　which　I　necessarily　will　this　other　thing；　and　this
  law　again　requires　an　imperative　to　restrict　this　maxim。　For　the
  influence　which　the　conception　of　an　object　within　the　reach　of　our
  faculties　can　exercise　on　the　will　of　the　subject；　in　consequence　of
  its　natural　properties；　depends　on　the　nature　of　the　subject；　either
  the　sensibility　（inclination　and　taste）；　or　the　understanding　and
  reason；　the　employment　of　which　is　by　the　peculiar　constitution　of
  their　nature　attended　with　satisfaction。　It　follows　that　the　law　would
  be；　properly　speaking；　given　by　nature；　and；　as　such；　it　must　be　known
  and　proved　by　experience　and　would　consequently　be　contingent　and
  therefore　incapable　of　being　an　apodeictic　practical　rule；　such　as　the
  moral　rule　must　be。　Not　only　so；　but　it　is　inevitably　only　heteronomy；
  the　will　does　not　give　itself　the　law；　but　is　given　by　a　foreign
  impulse　by　means　of　a　particular　natural　constitution　of　the　subject
  adapted　to　receive　it。　An　absolutely　good　will；　then；　the　principle　of
  which　must　be　a　categorical　imperative；　will　be　indeterminate　as
  regards　all　objects　and　will　contain　merely　the　form　of　volition
  generally；　and　that　as　autonomy；　that　is　to　say；　the　capability　of　the
  maxims　of　every　good　will　to　make　themselves　a　universal　law；　is
  itself　the　only　law　which　the　will　of　every　rational　being　imposes
  on　itself；　without　needing　to　assume　any　spring　or　interest　as　a
  foundation。
  How　such　a　synthetical　practical　a　priori　proposition　is　possible；
  and　why　it　is　necessary；　is　a　problem　whose　solution　does　not　lie
  within　the　bounds　of　the　metaphysic　of　morals；　and　we　have　not　here
  affirmed　its　truth；　much　less　professed　to　have　a　proof　of　it　in　our
  power。　We　simply　showed　by　the　development　of　the　universally　received
  notion　of　morality　that　an　autonomy　of　the　will　is　inevitably
  connected　with　it；　or　rather　is　its　foundation。　Whoever　then　holds
  morality　to　be　anything　real；　and　not　a　chimerical　idea　without　any
  truth；　must　likewise　admit　the　principle　of　it　that　is　here
  assigned。　This　section　then；　like　the　first；　was　merely　analytical。
  Now　to　prove　that　morality　is　no　creation　of　the　brain；　which　it
  cannot　be　if　the　categorical　imperative　and　with　it　the　autonomy　of
  the　will　is　true；　and　as　an　a　priori　principle　absolutely　necessary；
  this　supposes　the　possibility　of　a　synthetic　use　of　pure　practical
  reason；　which　however　we　cannot　venture　on　without　first　giving　a
  critical　examination　of　this　faculty　of　reason。　In　the　concluding
  section　we　shall　give　the　principal　outlines　of　this　critical
  examination　as　far　as　is　sufficient　for　our　purpose。
  THIRD　SECTION
  TRANSITION　FROM　THE　METAPHYSIC　OF　MORALS　TO　THE
  CRITIQUE　OF　PURE　PRACTICAL　REASON
  The　Concept　of　Freedom　is　the　Key　that　explains　the　Autonomy　of
  the　Will
  The　will　is　a　kind　of　causality　belonging　to　living　beings　in　so　far
  as　they　are　rational；　and　freedom　would　be　this　property　of　such
  causality　that　it　can　be　efficient；　independently　of　foreign　causes
  determining　it；　just　as　physical　necessity　is　the　property　that　the
  causality　of　all　irrational　beings　has　of　being　determined　to　activity
  by　the　influence　of　foreign　causes。
  The　preceding　definition　of　freedom　is　negative　and　therefore
  unfruitful　for　the　discovery　of　its　essence；　but　it　leads　to　a
  positive　conception　which　is　so　much　the　more　full　and　fruitful。
  Since　the　conception　of　causality　involves　that　of　laws；　according
  to　which；　by　something　that　we　call　cause；　something　else；　namely
  the　effect；　must　be　produced；　hence；　although　freedom　is　not　a
  property　of　the　will　depending　on　physical　laws；　yet　it　is　not　for
  that　reason　lawless；　on　the　contrary　it　must　be　a　causality　acting
  according　to　immutable　laws；　but　of　a　peculiar　kind；　otherwise　a
  free　will　would　be　an　absurdity。　Physical　necessity　is　a　heteronomy　of
  the　efficient　causes；　for　every　effect　is　possible　only　according　to
  this　law；　that　something　else　determines　the　efficient　cause　to
  exert　its　causality。　What　else　then　can　freedom　of　the　will　be　but
  autonomy；　that　is；　the　property　of　the　will　to　be　a　law　to　itself？　But
  the　proposition：　〃The　will　is　in　every　action　a　law　to　itself；〃　only
  expresses　the　principle：　〃To　act　on　no　other　maxim　than　that　which　can
  also　have　as　an　object　itself　as　a　universal　law。〃　Now　this　is
  precisely　the　formula　of　the　categorical　imperative　and　is　the
  principle　of　morality；　so　that　a　free　will　and　a　will　subject　to　moral
  laws　are　one　and　the　same。
  On　the　hypothesis；　then；　of　freedom　of　the　will；　morality　together
  with　its　principle　follows　from　it　by　mere　analysis　of　the　conception。
  However；　the　latter　is　a　synthetic　proposition；　viz。；　an　absolutely
  good　will　is　that　whose　maxim　can　always　include　itself　regarded　as
  a　universal　law；　for　this　property　of　its　maxim　can　never　be
  discovered　by　analysing　the　conception　of　an　absolutely　good　will。　Now
  such　synthetic　propositions　are　only　possible　in　this　way：　that　the
  two　cognitions　are　connected　together　by　their　union　with　a　third　in
  which　they　are　both　to　be　found。　The　positive　concept　of　freedom
  furnishes　this　third　cognition；　which　cannot；　as　with　physical　causes；
  be　the　nature　of　the　sensible　world　（in　the　concept　of　which　we　find
  conjoined　the　concept　of　something　in　relation　as　cause　to　something
  else　as　effect）。　We　cannot　now　at　once　show　what　this　third　is　to
  which　freedom　points　us　and　of　which　we　have　an　idea　a　priori；　nor　can
  we　make　intelligible　how　the　concept　of　freedom　is　shown　to　be
  legitimate　from　principles　of　pure　practical　reason　and　with　it　the
  possibility　of　a　categorical　imperative；　but　some　further
  preparation　is　required。
  Freedom　must　be　presupposed　as　a　Property　of　the　Will
  of　all　Rational　Beings
  It　is　not　enough　to　predicate　freedom　of　our　own　will；　from　Whatever
  reason；　if　we　have　not　sufficient　grounds　for　predicating　the　same
  of　all　rational　beings。　For　as　morality　serves　as　a　law　for　us　only
  because　we　are　rational　beings；　it　must　also　hold　for　all　rational
  beings；　and　as　it　must　be　deduced　simply　from　the　property　of　freedom；
  it　must　be　shown　that　freedom　also　is　a　property　of　all　rational
  beings。　It　is　not　enough；　then；　to　prove　it　from　certain　supposed
  experiences　of　human　nature　（which　indeed　is　quite　impossible；　and
  it　can　only　be　shown　a　priori）；　but　we　must　show　that　it　belongs　to
  the　activity　of　all　rational　beings　endowed　with　a　will。　Now　I　say
  every　being　that　cannot　act　except　under　the　idea　of　freedom　is　just
  for　that　reason　in　a　practical　point　of　view　really　free；　that　is　to
  say；　all　laws　which　are　inseparably　connected　with　freedom　have　the
  same　force　for　him　as　if　his　will　had　been　shown　to　be　free　in
  itself　by　a　proof　theoretically　conclusive。*　Now　I　affirm　that　we　must
  attribute　to　every　rational　being　which　has　a　will　that　it　has　also
  the　idea　of　freedom　and　acts　entirely　under　this　idea。　For　in　such　a
  being　we　conceive　a　reason　that　is　practical；　that　is；　has　causality
  in　reference　to　its　objects。　Now　we　cannot　possibly　conceive　a
  reason　consciously　receiving　a　bias　from　any　other　quarter　with
  respect　to　its　judgements；　for　then　the　subject　would　ascribe　the
  determination　of　its　judgement　not　to　its　own　reason；　but　to　an
  impulse。　It　must　regard　itself　as　the　author　of　its　principles
  independent　of　foreign　influences。　Consequently　as　practical　reason　or
  as　the　will　of　a　rational　being　it　must　regard　itself　as　free；　that　is
  to　say；　the　will　of　such　a　being　cannot　be　a　will　of　its　own　except
  under　the　idea　of　freedom。　This　idea　must　therefore　in　a　practical
  point　of　view　be　ascribed　to　every　rational　being。
  *I　adopt　this　method　of　assuming　freedom　merely　as　an　idea　which
  rational　beings　suppose　in　their　actions；　in　order　to　avoid　the
  necessity　of　proving　it　in　its　theoretical　aspect　also。　The　former
  is　sufficient　for　my　purpose；　for　even　though　the　speculative　proof
  should　not　be　made　out；　yet　a　being　that　cannot　act　except　with　the
  idea　of　freedom　is　bound　by　the　same　laws　that　would　oblige　a　being
  who　was　actually　free。　Thus　we　can　escape　here　from　the　onus　which
  presses　on　the　theory。
  Of　the　Interest　attaching　to　the　Ideas　of　Morality
  We　have　finally　reduced　the　definite　conception　of　morality　to　the
  idea　of　freedom。　This　latter；　however；　we　could　not　prove　to　be
  actually　a　property　of　ourselves　or　of　human　nature；　only　we　saw
  that　it　must　be　presupposed　if　we　would　conceive　a　being　as　ra