readily　distinguish　here　between　the　two　significations　which　the
  question　may　have：　Whether　it　is　prudent；　or　whether　it　is　right；　to
  make　a　false　promise？　The　former　may　undoubtedly　of　be　the　case。　I　see
  clearly　indeed　that　it　is　not　enough　to　extricate　myself　from　a
  present　difficulty　by　means　of　this　subterfuge；　but　it　must　be　well
  considered　whether　there　may　not　hereafter　spring　from　this　lie　much
  greater　inconvenience　than　that　from　which　I　now　free　myself；　and
  as；　with　all　my　supposed　cunning；　the　consequences　cannot　be　so　easily
  foreseen　but　that　credit　once　lost　may　be　much　more　injurious　to　me
  than　any　mischief　which　I　seek　to　avoid　at　present；　it　should　be
  considered　whether　it　would　not　be　more　prudent　to　act　herein
  according　to　a　universal　maxim　and　to　make　it　a　habit　to　promise
  nothing　except　with　the　intention　of　keeping　it。　But　it　is　soon
  clear　to　me　that　such　a　maxim　will　still　only　be　based　on　the　fear
  of　consequences。　Now　it　is　a　wholly　different　thing　to　be　truthful
  from　duty　and　to　be　so　from　apprehension　of　injurious　consequences。　In
  the　first　case；　the　very　notion　of　the　action　already　implies　a　law
  for　me；　in　the　second　case；　I　must　first　look　about　elsewhere　to　see
  what　results　may　be　combined　with　it　which　would　affect　myself。　For　to
  deviate　from　the　principle　of　duty　is　beyond　all　doubt　wicked；　but
  to　be　unfaithful　to　my　maxim　of　prudence　may　often　be　very
  advantageous　to　me；　although　to　abide　by　it　is　certainly　safer。　The
  shortest　way；　however；　and　an　unerring　one；　to　discover　the　answer
  to　this　question　whether　a　lying　promise　is　consistent　with　duty；　is
  to　ask　myself；　〃Should　I　be　content　that　my　maxim　（to　extricate　myself
  from　difficulty　by　a　false　promise）　should　hold　good　as　a　universal
  law；　for　myself　as　well　as　for　others？　and　should　I　be　able　to　say
  to　myself；　〃Every　one　may　make　a　deceitful　promise　when　he　finds
  himself　in　a　difficulty　from　which　he　cannot　otherwise　extricate
  himself？〃　Then　I　presently　become　aware　that　while　I　can　will　the　lie；
  I　can　by　no　means　will　that　lying　should　be　a　universal　law。　For
  with　such　a　law　there　would　be　no　promises　at　all；　since　it　would　be
  in　vain　to　allege　my　intention　in　regard　to　my　future　actions　to　those
  who　would　not　believe　this　allegation；　or　if　they　over　hastily　did
  so　would　pay　me　back　in　my　own　coin。　Hence　my　maxim；　as　soon　as　it
  should　be　made　a　universal　law；　would　necessarily　destroy　itself。
  I　do　not；　therefore；　need　any　far…reaching　penetration　to　discern
  what　I　have　to　do　in　order　that　my　will　may　be　morally　good。
  Inexperienced　in　the　course　of　the　world；　incapable　of　being
  prepared　for　all　its　contingencies；　I　only　ask　myself：　Canst　thou　also
  will　that　thy　maxim　should　be　a　universal　law？　If　not；　then　it　must　be
  rejected；　and　that　not　because　of　a　disadvantage　accruing　from　it　to
  myself　or　even　to　others；　but　because　it　cannot　enter　as　a　principle
  into　a　possible　universal　legislation；　and　reason　extorts　from　me
  immediate　respect　for　such　legislation。　I　do　not　indeed　as　yet　discern
  on　what　this　respect　is　based　（this　the　philosopher　may　inquire）；
  but　at　least　I　understand　this；　that　it　is　an　estimation　of　the
  worth　which　far　outweighs　all　worth　of　what　is　recommended　by
  inclination；　and　that　the　necessity　of　acting　from　pure　respect　for
  the　practical　law　is　what　constitutes　duty；　to　which　every　other
  motive　must　give　place；　because　it　is　the　condition　of　a　will　being
  good　in　itself；　and　the　worth　of　such　a　will　is　above　everything。
  Thus；　then；　without　quitting　the　moral　knowledge　of　common　human
  reason；　we　have　arrived　at　its　principle。　And　although；　no　doubt；
  common　men　do　not　conceive　it　in　such　an　abstract　and　universal
  form；　yet　they　always　have　it　really　before　their　eyes　and　use　it　as
  the　standard　of　their　decision。　Here　it　would　be　easy　to　show　how；
  with　this　compass　in　hand；　men　are　well　able　to　distinguish；　in
  every　case　that　occurs；　what　is　good；　what　bad；　conformably　to　duty　or
  inconsistent　with　it；　if；　without　in　the　least　teaching　them
  anything　new；　we　only；　like　Socrates；　direct　their　attention　to　the
  principle　they　themselves　employ；　and　that；　therefore；　we　do　not
  need　science　and　philosophy　to　know　what　we　should　do　to　be　honest　and
  good；　yea；　even　wise　and　virtuous。　Indeed　we　might　well　have
  conjectured　beforehand　that　the　knowledge　of　what　every　man　is　bound
  to　do；　and　therefore　also　to　know；　would　be　within　the　reach　of
  every　man；　even　the　commonest。　Here　we　cannot　forbear　admiration
  when　we　see　how　great　an　advantage　the　practical　judgement　has　over
  the　theoretical　in　the　common　understanding　of　men。　In　the　latter；
  if　common　reason　ventures　to　depart　from　the　laws　of　experience　and
  from　the　perceptions　of　the　senses；　it　falls　into　mere
  inconceivabilities　and　self…contradictions；　at　least　into　a　chaos　of
  uncertainty；　obscurity；　and　instability。　But　in　the　practical　sphere
  it　is　just　when　the　common　understanding　excludes　all　sensible　springs
  from　practical　laws　that　its　power　of　judgement　begins　to　show
  itself　to　advantage。　It　then　becomes　even　subtle；　whether　it　be　that
  it　chicanes　with　its　own　conscience　or　with　other　claims　respecting
  what　is　to　be　called　right；　or　whether　it　desires　for　its　own
  instruction　to　determine　honestly　the　worth　of　actions；　and；　in　the
  latter　case；　it　may　even　have　as　good　a　hope　of　hitting　the　mark　as
  any　philosopher　whatever　can　promise　himself。　Nay；　it　is　almost　more
  sure　of　doing　so；　because　the　philosopher　cannot　have　any　other
  principle；　while　he　may　easily　perplex　his　judgement　by　a　multitude　of
  considerations　foreign　to　the　matter；　and　so　turn　aside　from　the　right
  way。　Would　it　not　therefore　be　wiser　in　moral　concerns　to　acquiesce　in
  the　judgement　of　common　reason；　or　at　most　only　to　call　in
  philosophy　for　the　purpose　of　rendering　the　system　of　morals　more
  complete　and　intelligible；　and　its　rules　more　convenient　for　use
  （especially　for　disputation）；　but　not　so　as　to　draw　off　the　common
  understanding　from　its　happy　simplicity；　or　to　bring　it　by　means　of
  philosophy　into　a　new　path　of　inquiry　and　instruction？
  Innocence　is　indeed　a　glorious　thing；　only；　on　the　other　hand；　it　is
  very　sad　that　it　cannot　well　maintain　itself　and　is　easily　seduced。　On
  this　account　even　wisdom…　which　otherwise　consists　more　in　conduct
  than　in　knowledge…　yet　has　need　of　science；　not　in　order　to　learn　from
  it；　but　to　secure　for　its　precepts　admission　and　permanence。　Against
  all　the　commands　of　duty　which　reason　represents　to　man　as　so
  deserving　of　respect；　he　feels　in　himself　a　powerful　counterpoise　in
  his　wants　and　inclinations；　the　entire　satisfaction　of　which　he　sums
  up　under　the　name　of　happiness。　Now　reason　issues　its　commands
  unyieldingly；　without　promising　anything　to　the　inclinations；　and；
  as　it　were；　with　disregard　and　contempt　for　these　claims；　which　are　so
  impetuous；　and　at　the　same　time　so　plausible；　and　which　will　not　allow
  themselves　to　be　suppressed　by　any　command。　Hence　there　arises　a
  natural　dialectic；　i。e。；　a　disposition；　to　argue　against　these
  strict　laws　of　duty　and　to　question　their　validity；　or　at　least
  their　purity　and　strictness；　and；　if　possible；　to　make　them　more
  accordant　with　our　wishes　and　inclinations；　that　is　to　say；　to　corrupt
  them　at　their　very　source；　and　entirely　to　destroy　their　worth…　a
  thing　which　even　common　practical　reason　cannot　ultimately　call　good。
  Thus　is　the　common　reason　of　man　compelled　to　go　out　of　its
  sphere；　and　to　take　a　step　into　the　field　of　a　practical　philosophy；
  not　to　satisfy　any　speculative　want　（which　never　occurs　to　it　as
  long　as　it　is　content　to　be　mere　sound　reason）；　but　even　on
  practical　grounds；　in　order　to　attain　in　it　information　and　clear
  instruction　respecting　the　source　of　its　principle；　and　the　correct
  determination　of　it　in　opposition　to　the　maxims　which　are　based　on
  wants　and　inclinations；　so　that　it　may　escape　from　the　perplexity　of
  opposite　claims　and　not　run　the　risk　of　losing　all　genuine　moral
  principles　through　the　equivocation　into　which　it　easily　falls。
  Thus；　when　practical　reason　cultivates　itself；　there　insensibly　arises
  in　it　a　dialetic　which　forces　it　to　seek　aid　in　philosophy；　just　as
  happens　to　it　in　its　theoretic　use；　and　in　this　case；　therefore；　as
  well　as　in　the　other；　it　will　find　rest　nowhere　but　in　a　thorough
  critical　examination　of　our　reason。
  SECOND　SECTION
  TRANSITION　FROM　POPULAR　MORAL　PHILOSOPHY
  TO　THE　METAPHYSIC　OF　MORALS
  If　we　have　hitherto　drawn　our　notion　of　duty　from　the　common　use
  of　our　practical　reason；　it　is　by　no　means　to　be　inferred　that　we　have
  treated　it　as　an　empirical　notion。　On　the　contrary；　if　we　attend　to
  the　experience　of　men's　conduct；　we　meet　frequent　and；　as　we　ourselves
  allow；　just　complaints　that　one　cannot　find　a　single　certain　example
  of　the　disposition　to　act　from　pure　duty。　Although　many　things　are
  done　in　conformity　with　what　duty　prescrib