a discourse on method-第7章

按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！


　they　make　the　light　fall；　and　throwing　the　rest　into　the　shade；　allow　them　to　appear　only　in　so　far　as　they　can　be　seen　while　looking　at　the　principal　one；　so；　fearing　lest　I　should　not　be　able　to　compense　in　my　discourse　all　that　was　in　my　mind；　I　resolved　to　expound　singly；　though　at　considerable　length；　my　opinions　regarding　light；　then　to　take　the　opportunity　of　adding　something　on　the　sun　and　the　fixed　stars；　since　light　almost　wholly　proceeds　from　them；　on　the　heavens　since　they　transmit　it；　on　the　planets；　comets；　and　earth；　since　they　reflect　it；　and　particularly　on　all　the　bodies　that　are　upon　the　earth；　since　they　are　either　colored；　or　transparent；　or　luminous；　and　finally　on　man；　since　he　is　the　spectator　of　these　objects。　Further；　to　enable　me　to　cast　this　variety　of　subjects　somewhat　into　the　shade；　and　to　express　my　judgment　regarding　them　with　greater　freedom；　without　being　necessitated　to　adopt　or　refute　the　opinions　of　the　learned；　I　resolved　to　leave　all　the　people　here　to　their　disputes；　and　to　speak　only　of　what　would　happen　in　a　new　world；　if　God　were　now　to　create　somewhere　in　the　imaginary　spaces　matter　sufficient　to　compose　one；　and　were　to　agitate　variously　and　confusedly　the　different　parts　of　this　matter；　so　that　there　resulted　a　chaos　as　disordered　as　the　poets　ever　feigned；　and　after　that　did　nothing　more　than　lend　his　ordinary　concurrence　to　nature；　and　allow　her　to　act　in　accordance　with　the　laws　which　he　had　established。　　On　this　supposition；　I；　in　the　first　place；　described　this　matter；　and　essayed　to　represent　it　in　such　a　manner　that　to　my　mind　there　can　be　nothing　clearer　and　more　intelligible；　except　what　has　been　recently　said　regarding　God　and　the　soul；　for　I　even　expressly　supposed　that　it　possessed　none　of　those　forms　or　qualities　which　are　so　debated　in　the　schools；　nor　in　general　anything　the　knowledge　of　which　is　not　so　natural　to　our　minds　that　no　one　can　so　much　as　imagine　himself　ignorant　of　it。　　Besides；　I　have　pointed　out　what　are　the　laws　of　nature；　and；　with　no　other　principle　upon　which　to　found　my　reasonings　except　the　infinite　perfection　of　God；　I　endeavored　to　demonstrate　all　those　about　which　there　could　be　any　room　for　doubt；　and　to　prove　that　they　are　such；　that　even　if　God　had　created　more　worlds；　there　could　have　been　none　in　which　these　laws　were　not　observed。　　Thereafter；　I　showed　how　the　greatest　part　of　the　matter　of　this　chaos　must；　in　accordance　with　these　laws；　dispose　and　arrange　itself　in　such　a　way　as　to　present　the　appearance　of　heavens；　how　in　the　meantime　some　of　its　parts　must　compose　an　earth　and　some　planets　and　comets；　and　others　a　sun　and　fixed　stars。　　And；　making　a　digression　at　this　stage　on　the　subject　of　light；　I　expounded　at　considerable　length　what　the　nature　of　that　light　must　be　which　is　found　in　the　sun　and　the　stars；　and　how　thence　in　an　instant　of　time　it　traverses　the　immense　spaces　of　the　heavens；　and　how　from　the　planets　and　comets　it　is　reflected　towards　the　earth。　　To　this　I　likewise　added　much　respecting　the　substance；　the　situation；　the　motions；　and　all　the　different　qualities　of　these　heavens　and　stars；　so　that　I　thought　I　had　said　enough　respecting　them　to　show　that　there　is　nothing　observable　in　the　heavens　or　stars　of　our　system　that　must　not；　or　at　least　may　not　appear　precisely　alike　in　those　of　the　system　which　I　described。　　I　came　next　to　speak　of　the　earth　in　particular；　and　to　show　how；　even　though　I　had　expressly　supposed　that　God　had　given　no　weight　to　the　matter　of　which　it　is　composed；　this　should　not　prevent　all　its　parts　from　tending　exactly　to　its　center；　how　with　water　and　air　on　its　surface；　the　disposition　of　the　heavens　and　heavenly　bodies；　more　especially　of　the　moon；　must　cause　a　flow　and　ebb；　like　in　all　its　circumstances　to　that　observed　in　our　seas；　as　also　a　certain　current　both　of　water　and　air　from　east　to　west；　such　as　is　likewise　observed　between　the　tropics；　how　the　mountains；　seas；　fountains；　and　rivers　might　naturally　be　formed　in　it；　and　the　metals　produced　in　the　mines；　and　the　plants　grow　in　the　fields　and　in　general；　how　all　the　bodies　which　are　commonly　denominated　mixed　or　composite　might　be　generated　and；　among　other　things　in　the　discoveries　alluded　to　inasmuch　as　besides　the　stars；　I　knew　nothing　except　fire　which　produces　light；　I　spared　no　pains　to　set　forth　all　that　pertains　to　its　nature；　　the　manner　of　its　production　and　support；　and　to　explain　how　heat　is　sometimes　found　without　light；　and　light　without　heat；　to　show　how　it　can　induce　various　colors　upon　different　bodies　and　other　diverse　qualities；　how　it　reduces　some　to　a　liquid　state　and　hardens　others；　how　it　can　consume　almost　all　bodies；　or　convert　them　into　ashes　and　smoke；　and　finally；　how　from　these　ashes；　by　the　mere　intensity　of　its　action；　it　forms　glass：　　for　as　this　transmutation　of　ashes　into　glass　appeared　to　me　as　wonderful　as　any　other　in　nature；　I　took　a　special　pleasure　in　describing　it。　　I　was　not；　however；　disposed；　from　these　circumstances；　to　conclude　that　this　world　had　been　created　in　the　manner　I　described；　for　it　is　much　more　likely　that　God　made　it　at　the　first　such　as　it　was　to　be。　But　this　is　certain；　and　an　opinion　commonly　received　among　theologians；　that　the　action　by　which　he　now　sustains　it　is　the　same　with　that　by　which　he　originally　created　it；　so　that　even　although　he　had　from　the　beginning　given　it　no　other　form　than　that　of　chaos；　provided　only　he　had　established　certain　laws　of　nature；　and　had　lent　it　his　concurrence　to　enable　it　to　act　as　it　is　wont　to　do；　it　may　be　believed；　without　discredit　to　the　miracle　of　creation；　that；　in　this　way　alone；　things　purely　material　might；　in　course　of　time；　have　become　such　as　we　observe　them　at　present；　and　their　nature　is　much　more　easily　conceived　when　they　are　beheld　coming　in　this　manner　gradually　into　existence；　than　when　they　are　only　considered　as　produced　at　once　in　a　finished　and　perfect　state。

From　the　description　of　inanimate　bodies　and　plants；　I　passed　to　animals；　and　particularly　to　man。　　But　since　I　had　not　as　yet　sufficient　knowledge　to　enable　me　to　treat　of　these　in　the　same　manner　as　of　the　rest；　that　is　to　say；　by　deducing　effects　from　their　causes；　and　by　showing　from　what　elements　and　in　what　manner　nature　must　produce　them；　I　remained　satisfied　with　the　supposition　that　God　formed　the　body　of　man　wholly　like　to　one　of　ours；　as　well　in　the　external　shape　of　the　members　as　in　the　internal　conformation　of　the　organs；　of　the　same　matter　with　that　I　had　described；　and　at　first　placed　in　it　no　rational　soul；　nor　any　other　principle；　in　room　of　the　vegetative　or　sensitive　soul；　beyond　kindling　in　the　heart　one　of　those　fires　without　light；　such　as　I　had　already　described；　and　which　I　thought　was　not　different　from　the　heat　in　hay　that　has　been　heaped　together　before　it　is　dry；　or　that　which　causes　fermentation　in　new　wines　before　they　are　run　clear　of　the　fruit。　　For；　when　I　examined　the　kind　of　functions　which　might；　as　consequences　of　this　supposition；　exist　in　this　body；　I　found　precisely　all　those　which　may　exist　in　us　independently　of　all　power　of　thinking；　and　consequently　without　being　in　any　measure　owing　to　the　soul；　in　other　words；　to　that　part　of　us　which　is　distinct　from　the　body；　and　of　which　it　has　been　said　above　that　the　nature　distinctively　consists　in　thinking；　functions　in　which　the　animals　void　of　reason　may　be　said　wholly　to　resemble　us；　but　among　which　I　could　not　discover　any　of　those　that；　as　dependent　on　thought　alone；　belong　to　us　as　men；　while；　on　the　other　hand；　I　did　afterwards　discover　these　as　soon　as　I　supposed　God　to　have　created　a　rational　soul；　and　to　have　annexed　it　to　this　body　in　a　particular　manner　which　I　described。

But；　in　order　to　show　how　I　there　handled　this　matter；　I　mean　here　to　give　the　explication　of　the　motion　of　the　heart　and　arteries；　which；　as　the　first　and　most　general　motion　observed　in　animals；　will　afford　the　means　of　readily　determining　what　should　be　thought　of　all　the　rest。　　And　that　there　may　be　less　difficulty　in　understanding　what　I　am　about　to　say　on　this　subject；　I　advise　those　who　are　not　versed　in　anatomy；　before　they　commence　the　perusal　of　these　observations；　to　take　the　trouble　of　getting　dissected　in　their　presence　the　heart　of　some　large　animal　possessed　of　lungs　（for　this　is　throughout　sufficiently　like　the　human）；　and　to　have　shown　to　them　its　two　ventricles　or　cavities：　　in　the　first　place；　that　in　the　right　side；　with　which　correspond　two　very　ample　tubes；　viz。；　the　hollow　vein　（vena　cava）；　which　is　the　principal　receptacle　of　the　blood；　and　the　trunk　of　the　tree；　as　it　were；　of　which　all　the　other　veins　in　the　body　are　branches；　and　the　arterial　vein　（vena　arteriosa）；　inappropriately　so　denominated；　since　it　is　in　truth　only　an　artery；　which；　taking　its　rise　in　the　heart；　is　divided；　after　passing　out　from　it；　into　many　branches　which　presently　disperse　themselves　all　over　the　lungs；　in　the　second　place；　the　cavity　in　the　left　side；　with　which　correspond　in　the　same　manner　two　canals　in　size　equal　to　or　larger　than　the　preceding；　viz。；　the　venous　artery　（arteria　venosa）；　likewise　inappropriately　thus　designated；　because　it　is　simply　a　vein　which　comes　from　the　lungs；　where　it　is　divided　into　many　branches；　interlaced　with　those　of　the　arterial　vein；　and　those　of　the　tube　called　the　windpipe；　through　which　the　air　we　breathe　enters；　and　the　great　artery　which；　issuing　from　the　heart；　sends　its　branches　all　over　the　body。　　I　should　wish　also　that　such　persons　were　carefully　shown　the　eleven　pellicles　which；　like　so　many　small　valves；　open　and　shut　the　four　orifices　that　are　in　these　two　cavities；　viz。；　three　at　the　entrance　of　the　hollow　veins　where　they　are　disposed　in　such　a　manner　as　by　no　means　to　prevent　the　blood　which　it　contains　from　flowing　into　the　right　ventricle　of　the　heart；　and　yet　exactly　to　prevent　its　flowing　out；　three　at　the　entrance　to　the　arterial　vein；　which；　arranged　in　a　manner　exactly　the　opposite　of　the　former；　readily　permit　the　blood　contained　in　this　cavity　to　pass　into　the　lungs；　but　hinder　that　contained　in　the　lungs　from　returning　to　this　cavity；　and；　in　like　manner；　two　others　at　the　mouth　of　the　venous　artery；　which　allow　the　blood　from　the　lungs　to　flow　into　the　left　cavity　of　the　heart；　but　preclude　its　return；　and　three　at　the　mouth　of　the　great　artery；　which　suffer　the　blood　to　flow　from　the　heart；　but　prevent　its　reflux。　　Nor　do　we　need　to　seek　any　other　reason　for　the　number　of　these　pellicles　beyond　this　that　the　orifice　of　the　venous　artery　being　of　an　oval　shape　from　the　nature　of　its　situation；　can　be　adequately　closed　with　two；　whereas　the　others　being　round　are　more　conveniently　closed　with　three。　　Besides；　I　wish　such　persons　to　observe　that　the　grand　artery　and　the　arterial　vein　are　of　much　harder　and　firmer　texture　than　the　venous　artery　and　the　hollow　vein；　and　that　the　two　last　expand　before　entering　the　heart；　and　there　form；　as　it　were；　two　pouches　denominated　the　auricles　of　the　heart；　which　are　composed　of　a　substance　similar　to　that　of　the　heart　itself；　and　that　there　is　always　more　warmth　in　the　heart　than　in　any　other　part　of　the　body…　and　finally；　that　this　heat　is　capable　of　causing　any　drop　of　blood　that　passes　into　the