correlation　strictly　so　called；　just　as　in　the　first　form　of　necessity　it　is　substance。
  This　is　the　correlation　of　Causality。　At　the　stage　where　substance；　as　absolute
  power；　is　the　self…relating　power　（itself　a　merely　inner　possibility）；　which　thus
  determines　itself　to　be　accidentality　…　from　which　power　the　eternality　it　thereby
  creates　is　distinguished　…　necessity　is　a　correlation　strictly　so　called；　just　as　in　the
  first　form　of　necessity　it　is　substance。　This　is　the　correlation　of　Causality。
  （b）　The　Relationship　of　Causality
  §　153
  Substance　is　Cause；　in　so　far　as　substance　reflects　into　self　as　against　its　passage
  into　accidentality　and　so　stands　as　the　primary　fact；　but　again　no　less　suspends
  this　reflection…into…self　（its　bare　possibility）；　lays　itself　down　as　the　negative　of
  itself；　and　thus　produces　an　Effect；　an　actuality；　which；　though　so　far　only
  assumed　as　a　sequence；　is　through　the　process　that　effectuates　it　at　the　same　time
  necessary。
  As　primary　fact；　the　cause　is　qualified　as　having　absolute　independence；　and　a
  subsistence　maintained　in　face　of　the　effect：　but　in　the　necessity；　whose　identity
  constitutes　that　primariness　itself；　it　is　wholly　passed　into　the　effect。　So　far　again
  as　we　can　speak　of　a　definite　content；　there　is　no　content　that　is　not　in　the　cause。
  That　identity　in　fact　is　the　absolute　content　itself：　but　it　is　no　less　also　the
  form…characteristic。　The　primariness　of　the　cause　is　suspended　in　the　effect　in
  which　the　cause　makes　itself　a　dependent　being。　The　cause　however　does　not　for
  that　reason　vanish　and　leave　the　effect　to　be　alone　actual。　For　this　dependency　is
  in　like　manner　directly　suspended；　and　is　rather　the　reflection　of　the　cause　in
  itself；　its　primariness：　in　short；　it　is　in　the　effect　that　the　cause　first　becomes　actual
  and　a　cause。　The　cause　consequently　is　in　its　full　truth　causa　sui。
  。　。　。　。＇re　Jacobi；　omitted＇
  In　the　common　acceptation　of　the　causal　relation　the　cause　is　finite；　to　such　extent
  as　its　content　is　so　（as　is　the　case　with　finite　substance）；　and　so　far　as　cause　and
  effect　are　conceived　as　two　several　independent　existences：　which　they　are；
  however；　only　when　we　leave　the　causal　relation　out　of　sight。　In　the　finite　sphere
  we　never　get　over　the　difference　of　the　form…characteristics　in　their　relation：　and
  hence　we　turn　the　matter　around　and　define　the　cause　also　as　something
  dependent　or　as　an　effect。　This　again　has　another　cause；　and　thus　there　grows　up
  a　progress　from　effects　to　causes　ad　infinitum。　There　is　a　descending　progress
  too：　the　effect；　looked　at　in　its　identity　with　the　cause；　is　itself　defined　as　a　cause；
  and　at　the　same　time　as　another　cause；　which　again　has　other　effects；　and　so　on
  for　ever。
  §　153n
  The　way　understanding　bristles　up　against　the　idea　of　substance　is　equalled　by　its　readiness　to　use
  the　relation　of　cause　and　effect。　Whenever　it　is　proposed　to　view　any　sum　of　facts　as　necessary；　it
  is　especially　the　relation　of　causality　to　which　the　reflective　understanding　makes　a　point　of　tracing
  of　it　back。　Now；　although　this　relation　does　undoubtedly　belong　to　necessity；　it　forms　only　one
  aspect　in　the　process　of　that　category。　That　process　equally　requires　the　suspension　of　the
  mediation　involved　in　causality　and　the　exhibition　of　it　as　simple　self…relation。　If　we　stick　to
  causality　as　such；　we　have　it　not　in　its　truth。　Such　a　causality　is　merely　finite；　and　its　finitude　lies　in
  retaining　the　distinction　between　cause　and　effect　unassimilated。　But　these　two　terms；　if　they　are
  distinct；　are　also　identical。　Even　in　ordinary　consciousness　that　identity　may　be　found。　We　say　that
  a　cause　is　a　cause；　only　where　it　has　an　effect；　and　vice　versa。　Both　cause　and　effect　are　thus　one
  and　the　same　content：　and　the　distinction　between　them　is　primarily　only　that　the　one　lays　down；
  and　the　other　is　laid　down。　This　formal　difference　however　again　suspends　itself；　because　the
  cause　is　not　only　a　cause　of　something　else；　but　also　a　cause　of　itself；　while　the　effect　is　not　only　an
  effect　of　something　else；　but　also　an　effect　of　itself。　The　finitude　of　things　consists　accordingly　in
  this。　While　cause　and　effect　are　in　their　motion　identical；　the　two　forms　present　themselves　severed
  so　that；　though　the　cause　is　also　an　effect；　and　the　effect　also　a　cause；　the　cause　is　not　an　effect　in
  the　same　connection　as　it　is　an　effect。　This　again　gives　the　infinite　progress；　in　the　shape　of　an
  endless　series　of　causes；　which　shows　itself　at　the　same　time　as　an　endless　series　of　effects。
  §　154
  Action　and　Reaction
  The　effect　is　different　from　the　cause。　The　former　as　such　has　a　being　dependent
  on　the　latter。　But　such　a　dependence　is　likewise　reflection…into…self　and
  immediacy：　and　the　action　of　the　cause；　as　it　constitutes　the　effect；　is　at　the　same
  time　the　pre…constitution　of　the　effect；　so　long　as　effect　is　kept　separate　from
  cause。　There　is　already　in　existence　another　substance　on　which　the　effect　takes
  place。　As　immediate；　this　substance　is　not　a　self…related　negativity　and　active；　but
  passive。　Yet　it　is　a　substance；　and　it　is　therefore　active　also：　it　therefore　suspends
  the　immediacy　it　was　originally　put　forward　with；　and　the　effect　which　was　put
  into　it：　it　reacts；　i。e。　suspends　the　activity　of　the　first　substance。　But　this　first
  substance　also　in　the　same　way　sets　aside　its　own　immediacy；　or　the　effect　which
  is　put　into　it；　it　thus　suspends　the　activity　of　the　other　substance　and　reacts。　In　this
  manner　causality　passes　into　the　relation　of　Action　and　Reaction；　or
  Reciprocity。
  In　Reciprocity；　although　causality　is　not　yet　invested　with　its　true　characteristic；
  the　rectilinear　movement　out　from　causes　to　effects；　and　from　effects　to　causes；
  is　bent　round　and　back　into　Itself；　and　thus　the　progress　ad　infinitum　of　causes
  and　effects　is；　as　a　progress；　really　and　truly　suspended。　This　bend；　which
  transforms　the　infinite　progression　into　a　self…contained　relationship；　here　as
  always　the　plain　reflection　that　in　the　above　meaningless　repetition　there　is　only
  one　and　the　same　thing；　viz。　one　cause　and　another；　and　their　connection　with
  one　another。　Reciprocity　…　which　is　the　development　of　this　relation　…　itself
  however　only　distinguishes　turn　and　turn　about—not　causes；　but　factors　of
  causation；　in　each　of　which；　just　because　they　are　inseparable　（on　the　principle　of
  the　identity　that　the　cause　is　cause　in　the　effect；　and　vice　versa）；　the　other　factor
  is　also　equally　supposed。
  （c）　Reciprocity；　or　Action　&　Reaction
  §　155
  The　characteristics　which　in　Reciprocal　Action　are　retained　as　distinct　are　＇a＇
  potentially　the　same。　The　one　side　is　a　cause；　is　primary；　active；　passive；　etc。；　just
  as　the　other　is。　Similarly　the　presupposition　of　another　side　and　the　action　upon　it；
  the　immediate　primariness　and　the　dependence　produced　by　the　alternation；　are
  one　and　the　same　on　both　sides。　The　cause　assumed　to　be　first　is　on　account　of
  its　immediacy　passive；　a　dependent　being；　and　an　effect。　The　distinction　of　the
  causes　spoken　of　as　two　is　accordingly　void：　and　properly　speaking　there　is　only
  one　cause；　which；　while　it　suspends　itself　（as　substance）　in　its　effect；　also　rises　in
  this　operation　only　to　independent　existence　as　a　cause。
  §　156
  But　this　unity　of　the　double　cause　is　also　＇b＇　actual。　All　this　alternation　is　properly
  the　cause　in　act　of　constituting　itself　and　in　such　constitution　lies　its　being。　The
  nullity　of　the　distinctions　is　not　only　potential；　or　a　reflection　of　ours　（§　I55）。
  Reciprocal　action　just　means　that　each　characteristic　we　impose　is　also　to　be
  suspended　and　inverted　into　its　opposite；　and　that　in　this　way　the　essential　nullity
  of　the　'moments'　is　explicitly　stated。　An　effect　is　introduced　into　the　primariness；
  in　other　words；　the　primariness　is　abolished：　the　action　of　a　cause　becomes
  reaction　and　so　on。
  §　156n
  Reciprocal　action　realises　the　causal　relation　in　its　complete　development。　It　is　this　relation；
  therefore；　in　which　reflection　usually　takes　shelter　when　the　conviction　grows　that　things　can　no
  longer　be　studied　satisfactorily　from　a　causal　point　of　view；　on　account　of　the　infinite　progress
  already　spoken　of。　Thus　in　historical　research　the　question　may　be　raised　in　a　first　form；　whether
  the　character　and　manners　of　a　nation　are　the　cause　of　its　constitution　and　its　laws；　or　if　they　are
  not　rather　the　effect。　Then；　as　the　second　step；　the　character　and　manners　on　one　side　and　the
  Constitution　and　laws　on　the　other　are　conceived　on　the　principle　of　reciprocity：　and　in　that　case
  the　cause　in　the　same　connection　as　it　is　a　cause　will　at　the　same　time　be　an　effect；　and　vice　versa。
  The　same　thing　is　done　in　the　study　of　Nature；　and　especially　of　living　organisms。　There　the　sexual
  organs　and　functions　are　similarly　seen　to　stand　to　each　other　in　the　relation　of　reciprocity。
  Reciprocity　is　undoubtedly　the　proximate　truth　of　the　relation　of　cause　and　effect