darwin and modern science-第4节

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e　somewhat　simpler；　that　these　again　are　descended　from　yet　simpler　forms；　and　so　on　backwards　towards　the　literal　〃Protozoa〃　and　〃Protophyta〃　about　which　we　unfortunately　know　nothing。　　Now　no　one　supposes　that　Darwin　originated　this　idea；　which　in　rudiment　at　least　is　as　old　as　Aristotle。　　What　Darwin　did　was　to　make　it　current　intellectual　coin。　　He　gave　it　a　form　that　commended　itself　to　the　scientific　and　public　intelligence　of　the　day；　and　he　won　wide…spread　conviction　by　showing　with　consummate　skill　that　it　was　an　effective　formula　to　work　with；　a　key　which　no　lock　refused。　　In　a　scholarly；　critical；　and　pre…eminently　fair…minded　way；　admitting　difficulties　and　removing　them；　foreseeing　objections　and　forestalling　them；　he　showed　that　the　doctrine　of　descent　supplied　a　modal　interpretation　of　how　our　present…day　fauna　and　flora　have　come　to　be。

（II）　　In　the　second　place；　Darwin　applied　the　evolution…idea　to　particular　problems；　such　as　the　descent　of　man；　and　showed　what　a　powerful　organon　it　is；　introducing　order　into　masses　of　uncorrelated　facts；　interpreting　enigmas　both　of　structure　and　function；　both　bodily　and　mental；　and；　best　of　all；　stimulating　and　guiding　further　investigation。　　But　here　again　it　cannot　be　claimed　that　Darwin　was　original。　　The　problem　of　the　descent　or　ascent　of　man；　and　other　particular　cases　of　evolution；　had　attracted　not　a　few　naturalists　before　Darwin's　day；　though　no　one　（except　Herbert　Spencer　in　the　psychological　domain　（1855））　had　come　near　him　in　precision　and　thoroughness　of　inquiry。

（III）　　In　the　third　place；　Darwin　contributed　largely　to　a　knowledge　of　the　factors　in　the　evolution…process；　especially　by　his　analysis　of　what　occurs　in　the　case　of　domestic　animals　and　cultivated　plants；　and　by　his　elaboration　of　the　theory　of　Natural　Selection；　which　Alfred　Russel　Wallace　independently　stated　at　the　same　time；　and　of　which　there　had　been　a　few　previous　suggestions　of　a　more　or　less　vague　description。　　It　was　here　that　Darwin's　originality　was　greatest；　for　he　revealed　to　naturalists　the　many　different　formsoften　very　subtlewhich　natural　selection　takes；　and　with　the　insight　of　a　disciplined　scientific　imagination　he　realised　what　a　mighty　engine　of　progress　it　has　been　and　is。

（IV）　　As　an　epoch…marking　contribution；　not　only　to　Aetiology　but　to　Natural　History　in　the　widest　sense；　we　rank　the　picture　which　Darwin　gave　to　the　world　of　the　web　of　life；　that　is　to　say；　of　the　inter…relations　and　linkages　in　Nature。　　For　the　Biology　of　the　individualif　that　be　not　a　contradiction　in　termsno　idea　is　more　fundamental　than　that　of　the　correlation　of　organs；　but　Darwin's　most　characteristic　contribution　was　not　less　fundamental；it　was　the　idea　of　the　correlation　of　organisms。　　This；　again；　was　not　novel；　we　find　it　in　the　works　of　naturalist　like　Christian　Conrad　Sprengel；　Gilbert　White；　and　Alexander　von　Humboldt；　but　the　realisation　of　its　full　import　was　distinctively　Darwinian。

AS　REGARDS　THE　GENERAL　IDEA　OF　ORGANIC　EVOLUTION。

While　it　is　true；　as　Prof。　H。F。　Osborn　puts　it；　that　〃'Before　and　after　Darwin'　will　always　be　the　ante　et　post　urbem　conditam　of　biological　history；〃　it　is　also　true　that　the　general　idea　of　organic　evolution　is　very　ancient。　　In　his　admirable　sketch　〃From　the　Greeks　to　Darwin〃　（〃Columbia　University　Biological　Series〃；　Vol。　I。　New　York　and　London；　1894。　　We　must　acknowledge　our　great　indebtness　to　this　fine　piece　of　work。）；　Prof。　Osborn　has　shown　that　several　of　the　ancient　philosophers　looked　upon　Nature　as　a　gradual　development　and　as　still　in　process　of　change。　　In　the　suggestions　of　Empedocles；　to　take　the　best　instance；　there　were　〃four　sparks　of　truth；first；　that　the　development　of　life　was　a　gradual　process；　second；　that　plants　were　evolved　before　animals；　third；　that　imperfect　forms　were　gradually　replaced　（not　succeeded）　by　perfect　forms；　fourth；　that　the　natural　cause　of　the　production　of　perfect　forms　was　the　extinction　of　the　imperfect。〃　　（Op。　cit。　page　41。）　　But　the　fundamental　idea　of　one　stage　giving　origin　to　another　was　absent。　　As　the　blue　Aegean　teemed　with　treasures　of　beauty　and　threw　many　upon　its　shores；　so　did　Nature　produce　like　a　fertile　artist　what　had　to　be　rejected　as　well　as　what　was　able　to　survive；　but　the　idea　of　one　species　emerging　out　of　another　was　not　yet　conceived。

Aristotle's　views　of　Nature　（See　G。J。　Romanes；　〃Aristotle　as　a　Naturalist〃；　〃Contemporary　Review〃；　Vol。　LIX。　page　275；　1891；　G。　Pouchet　〃La　Biologie　Aristotelique〃；　Paris；　1885；　E。　Zeller；　〃A　History　of　Greek　Philosophy〃；　London；　1881；　and　〃Ueber　die　griechischen　Vorganger　Darwin's〃；　〃Abhandl。　Berlin　Akad。〃　1878；　pages　111…124。）　seem　to　have　been　more　definitely　evolutionist　than　those　of　his　predecessors；　in　this　sense；　at　least；　that　he　recognised　not　only　an　ascending　scale；　but　a　genetic　series　from　polyp　to　man　and　an　age…long　movement　towards　perfection。　　〃It　is　due　to　the　resistance　of　matter　to　form　that　Nature　can　only　rise　by　degrees　from　lower　to　higher　types。〃　　〃Nature　produces　those　things　which；　being　continually　moved　by　a　certain　principle　contained　in　themselves；　arrive　at　a　certain　end。〃

To　discern　the　outcrop　of　evolution…doctrine　in　the　long　interval　between　Aristotle　and　Bacon　seems　to　be　very　difficult；　and　some　of　the　instances　that　have　been　cited　strike　one　as　forced。　　Epicurus　and　Lucretius；　often　called　poets　of　evolution；　both　pictured　animals　as　arising　directly　out　of　the　earth；　very　much　as　Milton's　lion　long　afterwards　pawed　its　way　out。　　Even　when　we　come　to　Bruno　who　wrote　that　〃to　the　sound　of　the　harp　of　the　Universal　Apollo　（the　World　Spirit）；　the　lower　organisms　are　called　by　stages　to　higher；　and　the　lower　stages　are　connected　by　intermediate　forms　with　the　higher；〃　there　is　great　room；　as　Prof。　Osborn　points　out　（op。　cit。　page　81。）；　for　difference　of　opinion　as　to　how　far　he　was　an　evolutionist　in　our　sense　of　the　term。

The　awakening　of　natural　science　in　the　sixteenth　century　brought　the　possibility　of　a　concrete　evolution　theory　nearer；　and　in　the　early　seventeenth　century　we　find　evidences　of　a　new　spiritin　the　embryology　of　Harvey　and　the　classifications　of　Ray。　　Besides　sober　naturalists　there　were　speculative　dreamers　in　the　sixteenth　and　seventeenth　centuries　who　had　at　least　got　beyond　static　formulae；　but；　as　Professor　Osborn　points　out　（op。　cit。　page　87。）；　〃it　is　a　very　striking　fact；　that　the　basis　of　our　modern　methods　of　studying　the　Evolution　problem　was　established　not　by　the　early　naturalists　nor　by　the　speculative　writers；　but　by　the　Philosophers。〃　　He　refers　to　Bacon；　Descartes；　Leibnitz；　Hume；　Kant；　Lessing；　Herder；　and　Schelling。　　〃They　alone　were　upon　the　main　track　of　modern　thought。　　It　is　evident　that　they　were　groping　in　the　dark　for　a　working　theory　of　the　Evolution　of　life；　and　it　is　remarkable　that　they　clearly　perceived　from　the　outset　that　the　point　to　which　observation　should　be　directed　was　not　the　past　but　the　present　mutability　of　species；　and　further；　that　this　mutability　was　simply　the　variation　of　individuals　on　an　extended　scale。〃

Bacon　seems　to　have　been　one　of　the　first　to　think　definitely　about　the　mutability　of　species；　and　he　was　far　ahead　of　his　age　in　his　suggestion　of　what　we　now　call　a　Station　of　Experimental　Evolution。　　Leibnitz　discusses　in　so　many　words　how　the　species　of　animals　may　be　changed　and　how　intermediate　species　may　once　have　linked　those　that　now　seem　discontinuous。　　〃All　natural　orders　of　beings　present　but　a　single　chain〃。。。〃All　advances　by　degrees　in　Nature；　and　nothing　by　leaps。〃　　Similar　evolutionist　statements　are　to　be　found　in　the　works　of　the　other　〃philosophers；〃　to　whom　Prof。　Osborn　refers；　who　were；　indeed；　more　scientific　than　the　naturalists　of　their　day。　　It　must　be　borne　in　mind　that　the　general　idea　of　organic　evolutionthat　the　present　is　the　child　of　the　pastis　in　great　part　just　the　idea　of　human　history　projected　upon　the　natural　world；　differentiated　by　the　qualification　that　the　continuous　〃Becoming〃　has　been　wrought　out　by　forces　inherent　in　the　organisms　themselves　and　in　their　environment。

A　reference　to　Kant　（See　Brock；　〃Die　Stellung　Kant's　zur　Deszendenztheorie；〃　〃Biol。　Centralbl。〃　VIII。　1889；　pages　641…648。　　Fritz　Schultze；　〃Kant　und　Darwin〃；　Jena；　1875。）　should　come　in　historical　order　after　Buffon；　with　whose　writings　he　was　acquainted；　but　he　seems；　along　with　Herder　and　Schelling；　to　be　best　regarded　as　the　culmination　of　the　evolutionist　philosophersof　those　at　least　who　interested　themselves　in　scientific　problems。　　In　a　famous　passage　he　speaks　of　〃the　agreement　of　so　many　kinds　of　animals　in　a　certain　common　plan　of　structure〃。。。an　〃analogy　of　forms〃　which　〃strengthens　the　supposition　that　they　have　an　actual　blood…relationship；　due　to　derivation　from　a　common　parent。〃　　He　speaks　of　〃the　great　Family　of　creatures；　for　as　a　Family　we　must　conceive　it；　if　the　above…mentioned　continuous　and　connected　relationship　has　a　real　foundation。〃　　Prof。　Osborn　alludes　to　the　scientific　caution　which　led　Kant；　biology　being　what　it　was；　to　refuse　to　entertain　the　hope　〃that　a　Newton　may　one　day　arise　even　to　make　the　production　of　a　blade　of　grass　comprehensible；　according　to　natural　laws　ordained　by　no　intention。〃　　As　Pro