thoughts on man-第54部分

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have　sixty　and　three　times　more　pores　than　solid　parts。

And　so　on　perpetually＇44＇。〃

＇44＇　Ibid。


In　the　Queries　annexed　to　the　Optics；　Newton　further　suggests　an　opinion；　that　the　rays　of　light　are　repelled　by　bodies　without　immediate　contact。　　He　observes　that：

〃Where　attraction　ceases；　there　a　repulsive　virtue　ought　to　succeed。　　And　that　there　is　such　a　virtue；　seems　to　follow　from　the　reflexions　and　inflexions　of　the　rays　of　light。　　For　the　rays　are　repelled　by　bodies；　in　both　these　cases；　without　the　immediate　contact　of　the　reflecting　or　inflecting　body。　　It　seems　also　to　follow　from　the　emission　of　light；　the　ray；　so　soon　as　it　is　shaken　off　from　a　shining　body　by　the　vibrating　motion　of　the　parts　of　the　body；　and　gets　beyond　the　reach　of　attraction；　being　driven　away　with　exceeding　great　velocity。　　For　that　force；　which　is　sufficient　to　turn　it　back　in　reflexion；　may　be　sufficient　to　emit　it。　　It　seems　also　to　follow　from　the　production　of　air　and　vapour：　　the　particles；　when　they　are　shaken　off　from　bodies　by　heat　or　fermentation；　so　soon　as　they　are　beyond　the　reach　of　the　attraction　of　the　body；　receding　from　it　and　also　from　one　another；　with　great　strength；　and　keeping　at　a　distance；　so　as　sometimes　to　take　up　a　million　of　times　more　space　than　they　did　before；　in　the　form　of　a　dense　body。〃

Newton　was　of　opinion　that　matter　was　made　up；　in　the　last　resort；　of　exceedingly　small　solid　particles；　having　no　pores；　or　empty　spaces　within　them。　　Priestley；　in　his　Disquisitions　relating　to　Matter　and　Spirit；　carries　the　theory　one　step　farther；　and；　as　Newton　surrounds　his　exceedingly　small　particles　with　spheres　of　attraction　and　repulsion；　precluding　in　all　cases　their　actual　contact；　Priestley　is　disposed　to　regard　the　centre　of　these　spheres　as　mathematical　points　only。　　If　there　is　no　actual　contact；　then　by　the　very　terms　no　two　particles　of　matter　were　ever　so　near　to　each　other；　but　that　they　might　be　brought　nearer；　if　a　sufficient　force　could　be　applied　for　that　purpose。　　You　had　only　another　sphere　of　repulsion　to　conquer；　and；　as　there　never　is　actual　contact；　the　whole　world　is　made　up　of　one　sphere　of　repulsion　after　another；　without　the　possibility　of　ever　arriving　at　an　end。

〃The　principles　of　the　Newtonian　philosophy；〃　says　our　author；　〃were　no　sooner　known；　than　it　was　seen　how　few　in　comparison；　of　the　phenomena　of　nature；　were　owing　to　solid　matter；　and　how　much　to　powers；　which　were　only　supposed　to　accompany　and　surround　the　solid　parts　of　matter。　　It　has　been　asserted；　and　the　assertion　has　never　been　disproved；　that　for　any　thing　we　know　to　the　contrary；　all　the　solid　matter　in　the　solar　system　might　be　contained　within　a　nutshell＇45＇。〃

＇45＇　Priestley；　Disquisitions；　Section　II。　　I　know　not　by　whom　this　illustration　was　first　employed。　　Among　other　authors；　I　find；　in　Fielding　（Joseph　Andrews；　Book　II；　Chap。　II）；　a　sect　of　philosophers　spoken　of；　who　〃can　reduce　all　the　matter　of　the　world　into　a　nutshell。〃


It　is　then　with　senses；　from　the　impressions　upon　which　we　are　impelled　to　draw　such　false　conclusions；　and　that　present　us　with　images　altogether　unlike　any　thing　that　exists　out　of　ourselves；　that　we　come　to　observe　the　phenomena　of　what　we　call　the　universe。　　The　first　observation　that　it　is　here　incumbent　on　us　to　make；　and　which　we　ought　to　keep　ever　at　hand；　to　be　applied　as　occasion　may　offer；　is　the　well　known　aphorism　of　Socrates；　that　〃we　know　only　this；　that　we　know　nothing。〃　　We　have　no　compass　to　guide　us　through　the　pathless　waters　of　science；　we　have　no　revelation；　at　least　on　the　subject　of　astronomy；　and　of　the　unnumbered　inhabitable　worlds　that　float　in　the　ocean　of　ether；　and　we　are　bound　therefore　to　sail；　as　the　mariners　of　ancient　times　sailed；　always　within　sight　of　land。　　One　of　the　earliest　maxims　of　ordinary　prudence；　is　that　we　ought　ever　to　correct　the　reports　of　one　sense　by　the　assistance　of　another　sense。　　The　things　we　here　speak　of　are　not　matters　of　faith；　and　in　them　therefore　it　is　but　reason；　that　we　should　imitate　the　conduct　of　Didymus　the　apostle；　who　said；　〃Except　I　put　my　fingers　into　the　prints　of　the　nails；　and　thrust　my　hand　into　his　side；　I　will　not　believe。〃　　My　eyes　report　to　me　an　object；　as　having　a　certain　magnitude；　texture；　and　roughness　or　smoothness；　but　I　require　that　my　hands　should　confirm　to　me　the　evidence　of　my　eyes。　　I　see　something　that　appears　to　be　an　island　at　an　uncertain　distance　from　the　shore；　but；　if　I　am　actuated　by　a　laudable　curiosity；　and　wish　to　possess　a　real　knowledge；　I　take　a　boat；　and　proceed　to　ascertain　by　nearer　inspection；　whether　that　which　I　imagined　to　be　an　island　is　an　island　or　no。

There　are　indeed　many　objects　with　which　we　are　conversant；　that　are　in　so　various　ways　similar　to　each　other；　that；　after　having　carefully　examined　a　few；　we　are　satisfied　upon　slighter　investigation　to　admit　the　dimensions　and　character　of　others。　　Thus；　having　measured　with　a　quadrant　the　height　of　a　tower；　and　found　on　the　narrowest　search　and　comparison　that　the　report　of　my　instrument　was　right；　I　yield　credit　to　this　process　in　another　instance；　without　being　at　the　trouble　to　verify　its　results　in　any　more　elaborate　method。

The　reason　why　we　admit　the　inference　flowing　from　our　examination　in　the　second　instance；　and　so　onward；　with　less　scrupulosity　and　scepticism　than　in　the　first；　is　that　there　is　a　strict　resemblance　and　analogy　in　the　two　cases。　　Experience　is　the　basis　of　our　conclusions　and　our　conduct。　　I　strike　against　a　given　object；　a　nail　for　example；　with　a　certain　degree　of　force；　because　I　have　remarked　in　myself　and　others　the　effect　of　such　a　stroke。　　I　take　food　and　masticate　it；　because　I　have　found　that　this　process　contributes　to　the　sound　condition　of　my　body　and　mind。　　I　scatter　certain　seeds　in　my　field；　and　discharge　the　other　functions　of　an　agriculturist；　because　I　have　observed　that　in　due　time　the　result　of　this　industry　is　a　crop。　　All　the　propriety　of　these　proceedings　depends　upon　the　exact　analogy　between　the　old　case　and　the　new　one。　　The　state　of　the　affair　is　still　the　same；　when　my　business　is　merely　that　of　an　observer　and　a　traveller。　　I　know　water　from　earth；　land　from　sea；　and　mountains　from　vallies；　because　I　have　had　experience　of　these　objects；　and　confidently　infer　that；　when　certain　appearances　present　themselves　to　my　organs　of　sight；　I　shall　find　the　same　results　to　all　my　other　senses；　as　I　found　when　such　appearances　occurred　to　me　before。

But　the　interval　that　divides　the　objects　which　occur　upon　and　under　the　earth；　and　are　accessible　in　all　ways　to　our　examination；　on　the　one　hand；　and　the　lights　which　are　suspended　over　our　heads　in　the　heavens　on　the　other；　is　of　the　broadest　and　most　memorable　nature。　　Human　beings；　in　the　infancy　of　the　world；　were　contented　reverently　to　behold　these　in　their　calmness　and　beauty；　perhaps　to　worship　them；　and　to　remark　the　effects　that　they　produced；　or　seemed　to　produce；　upon　man　and　the　subjects　of　his　industry。　　But　they　did　not　aspire　to　measure　their　dimensions；　to　enquire　into　their　internal　frame；　or　to　explain　the　uses；　far　removed　from　our　sphere　of　existence；　which　they　might　be　intended　to　serve。

It　is　however　one　of　the　effects　of　the　improvement　of　our　intellect；　to　enlarge　our　curiosity。　　The　daringness　of　human　enterprise　is　one　of　the　prime　glories　of　our　nature。　　It　is　our　boast　that　we　undertake　to　〃measure　earth；　weigh　air；　and　state　the　tides。〃　　And；　when　success　crowns　the　boldness　of　our　aspirations　after　what　vulgar　and　timorous　prudence　had　pronounced　impossible；　it　is　then　chiefly　that　we　are　seen　to　participate　of　an　essence　divine。

What　has　not　man　effected　by　the　boldness　of　his　conceptions　and　the　adventurousness　of　his　spirit？　　The　achievements　of　human　genius　have　appeared　so　incredible；　till　they　were　thoroughly　examined；　and　slowly　established　their　right　to　general　acceptance；　that　the　great　heroes　of　intellect　were　universally　regarded　by　their　contemporaries　as　dealers　in　magic；　and　implements　of　the　devil。　　The　inventor　of　the　art　of　printing；　that　glorious　instrument　for　advancing　the　march　of　human　improvement；　and　the　discoverer　of　the　more　questionable　art　of　making　gunpowder；　alike　suffered　under　this　imputation。　　We　have　rendered　the　seas　and　the　winds　instruments　of　our　pleasure；　〃exhausted　the　old　world；　and　then　discovered　a　new　one；〃　have　drawn　down　lightning　from　heaven；　and　exhibited　equal　rights　and　independence　to　mankind。　　Still　however　it　is　incumbent　on　us　to　be　no　less　wary　and　suspicious　than　we　are　bold；　and　not　to　imagine；　because　we　have　done　much；　that　we　are　therefore　able　to　effect　every　thing。

As　was　stated　in　the　commencement　of　this　Essay；　we　know　our　own　sensations；　and　we　know　little　more。　　Matter；　whether　in　its　primary　or　secondary　qualities；　is　certainly　not　the　sort　of　thing　the　vulgar　imagine　it　to　be。　　The　illustrious　Berkeley　has　taught　many　to　doubt　of　its　existence　altogether；　and　later　theorists　have　gone　farther　than　this；　and　endeavoured　to　shew；　that　each　man；　himself　while　he　speaks　on　the　subject；　and　you　and　I　while　we　hear；　have　no　conclusive　evidence　to　convince　us；　that　we　may　not；　each　of　us；　for　aught　we　know；　be　the　only　thing　that　exists；　an　entire　universe　to　ourselves。

We　will　not　however　follow　these　ingenious　persons　to　the　startling　extreme　to　which　their　speculations　would　lead　us。　　But；　without　doing　so；　it　will　not　misbecome　us　to　be　cautious；　and　to　reflect　what　we　do；　before　we　take　a　leap　into　illimitable　space。


SECTION　II。

〃The　sun；〃　we　are　told；　〃is　a　solid　body；　ninety…five　millions　of　miles　distant　from　the　earth　we　inhabit；　one　million　times　larger　in　cubic　measurement；　and　to　such　a　degree　impregnated　with　heat；　that　a　comet；　approaching　to　it　within　a　certain　distance；　was　by　that　approximation　raised　to　a　heat　two　thousand　times　greater　than　that　of　red…hot　iron。〃

It　will　be　acknowledged；　that　there　is　in　this　statement　much　to　believe；　and　we　shall　not　be　exposed　to　reasonable　blame；　if　we　refuse　to　subscribe　to　it；　till　we　have　received　irresistible　evidence　of　its　truth。

It　has　already　been　observed；　that；　for　the　greater　part　of　what　we　imagine　we　know　on　the　surface　or　in　the