首页 >出版文学> A Defence of Free—Thinking in Mathematics>第1章
  ADefenceofFree—ThinkinginMathematicsInanswertoaPamphletofPhilalethesCantabrigiensis,intituled,GeometrynoFriendtoInfidelity,oraDefenceofSirISAACNEWTON,andtheBRITISHMathematicians。AlsoanAppendixconcerningMr。WALTON’SVindicationofthePrincipleofFluxionsagainsttheObjectionscontainedintheANALYST。
  WHEREIN
  ItisattemptedtoputthisControversyinsuchaLightasthateveryReadermaybeabletojudgethereof。ByGeorgeBerkeley1。WhenIreadyour`DefenceoftheBritishMathematicians,’
  Icouldnot,Sir,butadmireyourcourageinassertingwithsuchundoubtingassurancethingssoeasilydisproved。Thistomeseemedunaccountable,tillIreflectedonwhatyousay(p。32),when,uponmyhavingappealedtoeverythinkingreader,whetheritbepossibletoframeanyclearconceptionofFluxions,youexpressyourselfinthefollowingmanner,``Pray,Sir,whoarethosethinkingreadersyouappealto?Aretheygeometricians,orpersonswhollyignorantofgeometry?Iftheformer,Ileaveittothem:
  ifthelatter,Iask,Howwellaretheyqualifiedtojudgeofthemethodoffluxions?’’Itmustbeacknowledgedyouseembythisdilemmasecureinthefavourofonepartofyourreaders,andtheignoranceoftheother。
  Iamneverthelesspersuadedtherearefairandcandidmenamongthemathematicians。
  Andforthosewhoarenotmathematicians,Ishallendeavoursotounveilthismystery,andputthecontroversybetweenusinsuchalightasthateveryreaderofordinarysenseandreflectionmaybeacompetentjudgethereof。
  2。Youexpressanextremesurpriseandconcern,``thatIshouldtakesomuchpainstodepreciateoneofthenoblestsciences,todisparageandtraduceasetoflearnedmen,whoselabourssogreatlyconducetothehonourofthisisland(p。5);tolessenthereputationandauthorityofSirIsaacNewtonandhisfollowers,byshewingthattheyarenotsuchmastersofreasonastheyaregenerallypresumedtobe;andtodepreciatethesciencetheyprofess,bydemonstratingtotheworldthatitisnotofthatclearnessandcertaintyasiscommonlyimagined。’’Allwhich,youinsist,``appearsverystrangetoyouandtherestofthatfamousUniversity,whoplainlyseeofhowgreatusemathematicallearningistomankind。’’Henceyoutakeoccasiontodeclaimontheusefulnessofmathematicsintheseveralbranches,andthentoredoubleyoursurpriseandamazement(p。19and20)。ToallwhichdeclamationIreply,thatitisquitebesidethepurpose。For,Iallow,andalwayshaveallowed,itsfullclaimofmerittowhateverisusefulandtrueinthemathematics:butthatwhichisnotso,thelessitemploysmen’stimeandthoughtsthebetter。And,afterallyouhavesaidorcansay,Ibelievetheunprejudicedreaderwillthinkwithme,thatthingsobscurearenotthereforesacred;andthatitisnomoreacrimetocanvassanddetectunsoundprinciplesorfalsereasoningsinmathematicsthaninanyotherpartoflearning。
  3。Youare,itseems,muchatalosstounderstandtheusefulness,ortendency,orprudenceofmyattempt。IthoughtIhadsufficientlyexplainedthisinthe`Analyst。’Butforyourfurthersatisfactionshallheretellyou,itisverywellknownthatseveralpersonswhoderideFaithandMysteriesinReligion,admitthedoctrineofFluxionsfortrueandcertain。Now,ifitbeshewnthatfluxionsarereallymostincomprehensiblemysteries,andthatthosewhobelievethemtobeclearandscientificdoentertainanimplicitfaithintheauthorofthatmethod:willnotthisfurnishafairargumentumadhominemagainstmenwhorejectthatverythinginreligionwhichtheyadmitinhumanlearning?Andisitnotaproperwaytoabatethepride,anddiscreditthepretensionsofthosewhoinsistuponclearideasinpointsoffaith,ifitbeshewnthattheydowithoutthemeveninscience。
  4。Astomytimingthischarge;whynowandnotbefore,sinceIhadpublishedhintsthereofmanyyearsago?SurelyIamobligedtogivenoaccountofthis:ifwhathathbeensaidinthe`Analyst’
  benotsufficient。SupposethatIhadnotleisure,orthatIdidnotthinkitexpedient,orthatIhadnomindtoit。Whenamanthinksfittopublishanything,eitherinmathematicsorinotherpartoflearning,whatavailsit,orindeedwhatrighthathanyonetoask,Whyatthisorthattime;
  inthisorthatmanner;uponthisorthatmotive?LetthereaderjudgeifitsufficenotthatwhatIpublishistrue,andthatIhavearighttopublishsuchtruthswhenandhowIpleaseinafreecountry。
  5。Idonotsaythatmathematicians,assuch,areinfidels;orthatgeometryisafriendtoinfidelity,whichyouuntrulyinsinuate,asyoudomanyotherthings;whenceyouraisetopicsforinvective。
  ButIsaytherearecertainmathematicianswhoareknowntobeso;andthatthereareotherswhoarenotmathematicianswhoareinfluencedbyaregardfortheirauthority。Some,perhaps,wholiveintheUniversity,maynotbeapprisedofthis:buttheintelligentandobservingreader,wholivesintheworld,andisacquaintedwiththehumourofthetimesandthecharactersofmen,iswellawaretherearetoomanywhoderidemysteriesandyetadmirefluxions;whoyieldthatfaithtoameremortalwhichtheydenytoJesusChrist,whosereligiontheymakeittheirstudyandbusinesstodiscredit。Theowningthisisnottoownthatmenwhoreasonwellareenemiestoreligion,asyouwouldrepresentit:onthecontrary,Iendeavourtoshewthatsuchmenaredefectiveinpointofreasonandjudgement,andthattheydotheverythingtheywouldseemtodespise。
  6。Thereare,Imakenodoubt,amongthemathematiciansmanysincerebelieversinJesusChrist:Iknowseveralsuchmyself:butIaddressedmy`Analyst’toaninfidel;and,onverygoodgrounds,Isupposedthat,besideshim,therewereotherderidersoffaithwhohadneverthelessaprofoundvenerationforfluxions:andIwaswillingtosetforththeinconsistenceofsuchmen。Iftherebenosuchthingasinfidelswhopretendtoknowledgeinthemodernanalysis,Iownmyselfmisinformed,andshallgladlybefoundinamistake;buteveninthatcase,myremarksonfluxionsarenotthelesstrue;norwillitfollowthatIhavenorighttoexaminethemonthefootofhumanscience,eventhoughreligionwerequiteunconcerned,andthoughIhadnoendtoservebuttruth。Butyouareveryangry(p。
  13and14)thatIshouldenterthelistswithreasoninginfidels,andattackthemupontheirpretensionstoscience:andhenceyoutakeoccasionstoshewyourspleenagainsttheclergy。IwillnottakeuponmetosaythatIknowyoutobeaMinutePhilosopheryourself;butIknowtheMinutePhilosophersmakejustsuchcomplimentsasyoudotoourchurch,andarejustasangryasyoucanbeatanywhoundertaketodefendreligionbyreason。Ifweresolveallintofaith,theylaughatusandourfaith:andifweattempttoreason,theyareangryatus:theypretendwegooutofourprovince,andtheyrecommendtousablindimplicitfaith。Suchistheinconsistenceofouradversaries。Butitistobehopedtherewillneverbewantingmentodealwiththemattheirownweapons;andtoshewtheyarebynomeansthosemastersofreasonwhichtheywouldfainpassfor。
  7。Idonotsay,asyouwouldrepresentme,thatwehavenobetterreasonforourreligionthanyouhaveforfluxions:butIsaythataninfidel,whobelievesthedoctrineoffluxions,actsaveryinconsistentpartinpretendingtorejecttheChristianreligionbecausehecannotbelievewhathedothnotcomprehend;orbecausehecannotassentwithoutevidence;orbecausehecannotsubmithisfaithtoauthority。Whethertherearesuchinfidels,Isubmittothejudgementofthereader。FormyownpartImakenodoubtofit,havingseensomeshrewdsignsthereofmyself,andhavingbeenverycrediblyinformedthereofbyothers。Nordoththischargeseemthelesscredible,foryourbeingsosensiblytouched,anddenyingitwithsomuchpassion。You,indeed,donotsticktoaffirm,thatthepersonswhoinformedmeare``apackofbase,profligate,andimpudentliars’’(p。27)。Howfarthereaderwillthinkfittoadoptyourpassions,Icannotsay;butIcantrulysay,thelatecelebratedMr。Addisonisoneofthepersonswhomyouarepleasedtocharacteriseinthesemodestandmannerlyterms。Heassuredmethattheinfidelityofacertainnotedmathematician,stillliving,wasoneprincipalreasonassignedbyawittymanofthosetimesforhisbeinganinfidel。NotthatIimaginegeometrydisposethmentoinfidelity:butthat,fromothercauses,suchaspresumption,ignorance,orvanity,likeothermengeometriciansalsobecomeinfidels,andthatthesupposedlightandevidenceoftheirsciencegainscredittotheirinfidelity。
  8。Youreproachmewithcalumny,detraction,andartifice(p。15)。Yourecommendsuchmeansasareinnocentandjust,ratherthanthecriminalmethodoflesseningordetractingfrommyopponents(Ibid。)。
  Youaccusemeoftheodiumtheologicum,theintemperatezealofdivines,thatIdostaresuperviasantiquas(p。13);withmuchmoretothesameeffect。ForallwhichchargeIdependonthereader’scandour,thathewillnottakeyourword,butreadandjudgeforhimself。
  Inwhichcasehewillbeabletodiscern(thoughheshouldbenomathematician)
  howpassionateandunjustyourreproachesare,andhowpossibleitisforamantocryoutagainstcalumnyandpractiseitinthesamebreath。Consideringhowimpatientallmankindarewhentheirprejudicesarelookedinto,I
  donotwondertoseeyourailandrageattherateyoudo。Butifyourownimaginationbestronglyshockedandmoved,youcannotthereforeconcludethatasincereendeavourtofreeascience,sousefulandornamentaltohumanlife,fromthosesubtleties,obscurities,andparadoxeswhichrenderitinaccessibletomostmen,willbethoughtacriminalundertakingbysuchasareintheirrightmind。MuchlesscanyouhopethatanillustriousSeminaryoflearnedmen,whichhathproducedsomanyfree—spiritedinquiriesaftertruth,willatonceenterintoyourpassions,anddegenerateintoanestofbigots。
  9。Iobserveupontheinconsistencyofcertaininfidelanalysts。Iremarksomedefectsintheprinciplesofthemodernanalysis。
  ItakethelibertydecentlytodissentfromSirIsaacNewton。Iproposesomehelpstoabridgethetroubleofmathematicalstudies,andrenderthemmoreuseful。Whatisthereinallthisthatshouldmakeyoudeclaimontheusefulnessofpracticalmathematics;thatshouldmoveyoutocryout,Spain,Inquisition,OdiumTheologicum?Bywhatfigureofspeechdoyouextendwhatissaidofthemodernanalysistomathematicsingeneral;
  orwhatissaidofmathematicalinfidelstoallmathematicians;ortheconfutinganerrorinsciencetoburningorhangingtheauthors?Butitisnothingneworstrangethatmenshouldchoosetoindulgetheirpassions,ratherthanquittheiropinions,howabsurdsoever。Hencethefrightfulvisionsandtragicaluproarsofbigotedmen,bethesubjectoftheirbigotrywhatitwill。Averyremarkableinstanceofthisyougive(p。27),where,uponmyhavingsaidthatadeferencetocertainmathematicalinfidels,asIwascrediblyinformed,hadbeenonemotivetoinfidelity,youask,withnosmallemotion,``ForGod’ssakeareweinEnglandorinSpain?’’
  ``Isthisthelanguageofafamiliarwhoiswhisperinganinquisitor,&;c。?’’
  Andthepagebeforeyouexclaiminthefollowingwords—``LetusburnorhangupallthemathematiciansinGreatBritain,orhalloothemobuponthemtotearthemtopieceseverymother’ssonofthem,TrosRutulusvefuat,laymenorclergymen,&;c。LetusdigupthebodiesofDr。
  BarrowandSirIsaacNewton,andburnthemunderthegallows。’’
  10。Thereaderneednotbeamathematiciantoseehowvainallthistragedyofyoursis。AndifhebeasthoroughlysatisfiedasIamthatthecauseoffluxionscannotbedefendedbyreason,hewillbeaslittlesurprisedasIamtoseeyoubetakeyourselftotheartsofallbigotedmen,raisingterrorandcallinginthepassionstoyourassistance。
  Whetherthoserhetoricalflourishesabouttheinquisitionandthegallowsarenotquiteridiculous,Ileavetobedeterminedbythereader。Whowillalsojudge(thoughheshouldnotbeskilledingeometry)whetherIhavegiventheleastgroundsforthisandaworldofsuch—likedeclamation?
  AndwhetherIhavenotconstantlytreatedthosecelebratedwriterswithallproperrespect,thoughItakethelibertyincertainpointstodifferfromthem?
  11。AsIheartilyabhoraninquisitioninfaith,soIthinkyouhavenorighttoerectoneinscience。AtthetimeofwritingyourDefenceyouseemtohavebeenovercomewithpassion:but,nowyoumaybesupposedcool,Idesireyoutoreflectwhetheritbenotwroteinthetruespiritofaninquisitor?Whetherthisbecomesapersonsoexceedingdelicatehimselfuponthatpoint?Andwhetheryourbrethrentheanalystswillthinkthemselveshonouredorobligedbyyou,forhavingdefendedtheirdoctrineinthesamemannerasanydeclaimingbigotwoulddefendtransubstantiation?
  Thesamefalsecolours,thesameintemperatesallies,andthesameindignationagainstcommonsense!
  12。Inamatterofmerescience,whereauthorityhathnothingtodo,youconstantlyendeavourtooverbearmewithauthorities,andloadmewithenvy。IfIseeasophisminthewritingsofagreatauthor,and,incomplimenttohisunderstanding,suspecthecouldhardlybequitesatisfiedwithhisowndemonstration;thissetsyouondeclaimingforseveralpages。Itispompouslysetforth,asacriminalmethodofdetractingfromgreatmen,asaconcertedprojecttolessentheirreputation,asmakingthempassforimposters。IfIpublishmyfreethoughts,whichIhaveasmuchrighttopublishasanyotherman,itisimputedtorashness,andvanity,andtheloveofopposition。Thoughperhapsmylatepublication,ofwhathadbeenhintedtwenty—fiveyearsago,mayacquitmeofthischargeintheeyesofanimpartialreader。ButwhenIconsidertheperplexitiesthatbesetamanwhoundertakestodefendthedoctrineoffluxions,Icaneasilyforgiveyouranger。
  13。Twosortsoflearnedmenthereare:onewhocandidlyseektruthbyrationalmeans。Theseareneveraversetohavetheirprincipleslookedinto,andexaminedbythetestofreason。Anothersortthereiswholearnbyroteasetofprinciplesandawayofthinkingwhichhappentobeinvogue。Thesebetraythemselvesbytheirangerandsurprise,whenevertheirprinciplesarefreelycanvassed。Butyoumustnotexpectthatyourreaderwillmakehimselfapartytoyourpassionsoryourprejudices。IfreelyownthatSirIsaacNewtonhathshewedhimselfanextraordinarymathematician,aprofoundnaturalist,apersonofthegreatestabilitiesanderudition。ThusfarIcanreadilygo;butIcannotgothelengthsthatyoudo。Ishallneversayofhimasyoudo,Vestigiapronusadoro(p。70)。ThissameadorationthatyoupaytohimIwillpayonlytotruth。
  14。Youmay,indeed,yourselfbeanidolaterofwhomyouplease:butthenyouhavenorighttoinsultandexclaimatothermen,becausetheydonotadoreyouridol。GreatasSirIsaacNewtonwas,Ithinkhehath,onmoreoccasionsthanone,shewedhimselfnottobeinfallible。
  Particularly,hisdemonstrationofthedoctrineoffluxionsItaketobedefective;andIcannothelpthinkingthathewasnotquitepleasedwithithimself。Andyetthisdothnothinderbutthatthemethodmaybeuseful,consideredasanartofinvention。You,whoareamathematician,mustacknowledgetherehavebeendiverssuchmethodsadmittedinmathematics,whicharenotdemonstrative。Such,forinstance,aretheinductionsofDr。Wallis,inhisArithmeticofInfinites,andsuchwhatHarriot,andafterhim,Descartes,havewroteconcerningtherootsofaffectedequations。Itwillnot,nevertheless,thencefollowthatthosemethodsareuseless;butonlythattheyarenottobeallowedofaspremisesinastrictdemonstration。
  15。Nogreatnameuponearthshallevermakemeacceptthingsobscureforclear,orsophismsfordemonstrations。NormayyoueverhopetodetermefromfreelyspeakingwhatIfreelythink,bythoseargumentsadinvidiawhichateveryturnyouemployagainstme。Yourepresentyourself(p。52)asaman``whosehighestambitionisinthelowestdegreetoimitateSirIsaacNewton。’’Itmight,perhaps,havesuitedbetterwithyourappellationofPhilalethes,andbeenaltogetheraslaudable,ifyourhighestambitionhadbeentodiscovertruth。
  Veryconsistentlywiththecharacteryougiveofyourself,youspeakofitasasortofcrime(p。70)tothinkitpossibleyoushouldever``seefarther,orgobeyondSirIsaacNewton。’’AndIampersuadedyouspeakthesentimentsofmanymorebesidesyourself。Butthereareotherswhoarenotafraidtosifttheprinciplesofhumanscience,whothinkitnohonourtoimitatethegreatestmaninhisdefects,whoeventhinkitnocrimetodesiretoknow,notonlybeyondSirIsaacNewton,butbeyondallmankind。Andwhoeverthinksotherwise,Iappealtothereaderwhetherhecanproperlybecalledaphilosopher。
  16。BecauseIamnotguiltyofyourmeanidolatry,youinveighagainstmeasapersonconceitedofmyownabilities;notconsideringthatapersonoflessabilitiesmayknowmoreonacertainpointthanoneofgreater;notconsideringthatapurblindeye,inacloseandnarrowview,maydiscernmoreofathingthanamuchbettereyeinamoreextensiveprospect;notconsideringthatthisistofixaneplusultra,toputastoptoallfutureinquiries;lastly,notconsideringthatthisisinfact,somuchasinyoulies,convertingtherepublicoflettersintoanabsolutemonarchy,thatitisevenintroducingakindofphilosophicpoperyamongafreepeople。
  17。Ihavesaid(andIventurestilltosay)thatafluxionisincomprehensible:thatsecond,third,andfourthfluxionsareyetmoreincomprehensible:thatitisnotpossibletoconceiveasimpleinfinitesimal:thatitisyetlesspossibletoconceiveaninfinitesimalofaninfinitesimal,andsoonward。[`Analyst,’sect。4,5,6,&;c。]
  Whathaveyoutosayinanswertothis?Doyouattempttoclearupthenotionofafluxionoradifference?Nothinglikeit。Youonly``assureme(uponyourbareword)fromyourownexperience,andthatofseveralotherswhomyoucouldname,thatthedoctrineoffluxionsmaybeclearlyconceivedanddistinctlycomprehended;andthatifIampuzzledaboutitanddonotunderstandit,yetothersdo。’’Butcanyouthink,Sir,Ishalltakeyourword,whenIrefusetotakeyourmaster’s?
  18。Uponthispointeveryreaderofcommonsensemayjudgeaswellasthemostprofoundmathematician。Thesimpleapprehensionofathingdefinedisnotmademoreperfectbyanysubsequentprogressinmathematics。Whatanymanevidentlyknows,heknowsaswellasyouorSirIsaacNewton。Andeveryonecanknowwhethertheobjectofthismethodbe(asyouwouldhaveusthink)clearlyconceivable。Tojudgeofthisnodepthofscienceisrequisite,butonlyabareattentiontowhatpassesinhisownmind。Andthesameistobeunderstoodofalldefinitionsinallscienceswhatsoever。Innoneofwhichcanitbesupposedthatamanofsenseandspiritwilltakeanydefinitionorprincipleontrust,withoutsiftingittothebottom,andtryinghowfarhecanorhecannotconceiveit。ThisisthecourseIhavetaken,andshalltake,howeveryouandyourbrethrenmaydeclaimagainstit,andplaceitinthemostinvidiouslight。
  19。Itisusualwithyoutoadmonishmetolookoverasecondtime,toconsult,examine,weighthewordsofSirIsaac。
  InanswertowhichIwillventuretosaythatIhavetakenasmuchpainsas(Isincerelybelieve)anymanlivingtounderstandthatgreatauthor,andtomakesenseofhisprinciples。Noindustry,norcaution,norattention,Iassureyou,havebeenwantingonmypart。Sothat,ifIdonotunderstandhim,itisnotmyfaultbutmymisfortune。Uponothersubjectsyouarepleasedtocomplimentmewithdepthofthoughtanduncommonabilities(p。
  5and84)。ButIfreelyown,Ihavenopretencetothosethings。TheonlyadvantageIpretendtoisthatIhavealwaysthoughtandjudgedformyself。
  And,asIneverhadamasterinmathematics,soIfairlyfollowedthedictatesofmyownmindinexaminingandcensuringtheauthorsIreaduponthatsubject,withthesamefreedomthatIuseduponanyother;takingnothingontrust,andbelievingthatnowriterwasinfallible。Andamanofmoderateparts,whotakesthispainfulcourseinstudyingtheprinciplesofanyscience,maybesupposedtowalkmoresurelythanthoseofgreaterabilities,whosetoutwithmorespeedandlesscare。
  20。WhatIinsistonis,thattheideaofafluxion,simplyconsidered,isnotatallimprovedoramendedbyanyprogress,thougheversogreat,intheanalysis:neitherarethedemonstrationsofthegeneralrulesofthatmethodatallclearedupbyapplyingthem。Thereasonofwhichis,because,inoperatingorcalculating,mendonotreturntocontemplatetheoriginalprinciplesofthemethod,whichtheyconstantlypresuppose,butareemployedinworking,bynotesandsymbolsdenotingthefluxionssupposedtohavebeenatfirstexplained,andaccordingtorulessupposedtohavebeenatfirstdemonstrated。ThisIsaytoencouragethosewhoarenottoofargoneinthesestudies,touseintrepidlytheirownjudgement,withoutablindorameandeferencetothebestofmathematicians,whoarenomorequalifiedthantheyaretojudgeofthesimpleapprehension,ortheevidenceofwhatisdeliveredinthefirstelementsofthemethod;
  menbyfurtherandfrequentuseorexercisebecomingonlymoreaccustomedtothesymbolsandrules,whichdothnotmakeeithertheforegoingnotionsmoreclear,ortheforegoingproofsmoreperfect。Everyreaderofcommonsense,thatwillbutusehisfaculties,knowsaswellasthemostprofoundanalystwhatideaheframesorcanframeofvelocitywithoutmotion,orofmotionwithoutextension,ofmagnitudewhichisneitherfiniteorinfinite,orofaquantityhavingnomagnitudewhichisyetdivisible,ofafigurewherethereisnospace,ofproportionbetweennothings,orofarealproductfromnothingmultipliedbysomething。Heneednotbefargoneingeometrytoknowthatobscureprinciplesarenottobeadmittedindemonstration;
  thatifamandestroyshisownhypothesis,heatthesametimedestroyswhatwasbuiltuponit:thaterrorinthepremises,notrectified,mustproduceerrorintheconclusion。
  21。Inmyopinionthegreatestmenhavetheirprejudices。
  Menlearntheelementsofsciencefromothers:andeverylearnerhathadeferencemoreorlesstoauthority,especiallytheyounglearners,fewofthatkindcaringtodwelllonguponprinciples,butincliningrathertotakethemupontrust:andthingsearlyadmittedbyrepetitionbecomefamiliar:andthisfamiliarityatlengthpassethforevidence。Nowtomeitseemstherearecertainpointstacitlyadmittedbymathematicianswhichareneitherevidentnortrue。Andsuchpointsorprinciplesevermixingwiththeirreasoningsdoleadthemintoparadoxesandperplexities。Ifthegreatauthorofthefluxionarymethodwereearlyimbuedwithsuchnotionsitwouldonlyshewhewasaman。Andif,byvirtueofsomelatenterrorinhisprinciples,amanbedrawnintofallaciousreasonings,itisnothingstrangethatheshouldtakethemfortrue:andnevertheless,if,whenurgedbyperplexitiesanduncouthconsequences,anddriventoartsandshifts,heshouldentertainsomedoubtthereof,itisnomorethanonemaynaturallysupposemightbefallagreatgeniusgrapplingwithaninsuperabledifficulty:
  whichisthelightinwhichIhaveplacedSirIsaacNewton。[`Analyst,’
  sect。18。]HereuponyouarepleasedtoremarkthatIrepresentthegreatauthornotonlyasaweakbutasanillman,asadeceiverandanimpostor。
  Thereaderwilljudgehowjustly。
  22。Astotherestofyourcolouringsandglosses,yourreproachesandinsultsandoutcries,Ishallpassthemover,onlydesiringthereadernottotakeyourword,butreadwhatIhavewritten,andhewillwantnootheranswer。Ithathbeenoftenobservedthattheworstcauseproduceththegreatestclamour;andindeedyouaresoclamorousthroughoutyourdefencethatthereader,althoughheshouldbenomathematician,providedheunderstandscommonsense,andhathobservedthewaysofmen,willbeapttosuspectthatyouareinthewrong。Itshouldseem,therefore,thatyourbrethrentheanalystsarebutlittleobligedtoyouforthisnewmethodofdeclaiminginmathematics。WhethertheyaremoreobligedbyyourreasoningIshallnowexamine。
  23。Youaskme(p。32)whereIfindSirIsaacNewtonusingsuchexpressionsasthevelocitiesofvelocities,thesecond,third,andfourthvelocities,&;c。Thisyousetforthasapiousfraudandunfairrepresentation。Ianswer,thatifaccordingtoSirIsaacNewtonafluxionbethevelocityofanincrement,thenaccordingtohimImaycallthefluxionofafluxionthevelocityofavelocity。Butforthetruthoftheantecedentseehis`IntroductiontotheQuadratureofCurves,’wherehisownwordsare,Motuumvelincrementorumvelocitatesnominandofluxiones。
  SeealsothesecondlemmaofthesecondbookofhisMathematicalPrinciplesofNaturalPhilosophy,whereheexpressethhimselfinthefollowingmanner:Velocitatesincrementorumacdecrementorumquasetiam,motus,mutationes,etfluxionesquantitatumnominarelicet。Andthatheadmitsfluxionsoffluxions,orsecond,third,fourthfluxions,&;c。,seehisTreatiseoftheQuadratureofCurves。Iasknow,Isitnotplainthatifafluxionbeavelocity,thenthefluxionofafluxionmay,agreeablythereunto,becalledthevelocityofavelocity?Inlikemanner,ifbyafluxionismeantanascentaugment,willitnotthenfollowthatthefluxionofafluxionorsecondfluxionisthenascentaugmentofanascentaugment?
  Cananythingbeplainer?Letthereadernowjudgewhoisunfair。
  24。Ihadobservedthatthegreatauthorhadproceededillegitimately,inobtainingthefluxionormomentoftherectangleoftwoflowingquantities;andthathedidnotfairlygetridoftherectangleofthemoments。Inanswertothis,youallegethattheerrorarisingfromtheomissionofsuchrectangle(allowingittobeanerror)issosmallthatitisinsignificant。Thisyoudwelluponandexemplifytonootherpurposebuttoamuseyourreaderandmisleadhimfromthequestion;whichintruthisnotconcerningtheaccuracyofcomputingormeasuringinpractice,butconcerningtheaccuracyofthereasoninginscience。Thatthiswasreallythecase,andthatthesmallnessofthepracticalerrornowiseconcernsit,mustbesoplaintoanyonewhoreadsthe`Analyst’thatIwonderhowyoucouldbeignorantofit。
  25。YouwouldfainpersuadeyourreaderthatI
  makeanabsurdquarrelagainsterrorsofnosignificancyinpractice,andrepresentmathematiciansasproceedingblindfoldintheirapproximations,inallwhichIcannothelpthinkingthereisonyourparteithergreatignoranceorgreatdisingenuity。Ifyoumeantodefendthereasonablenessanduseofapproximationsorofthemethodofindivisibles,Ihavenothingtosay。Butthenyoumustrememberthisisnotthedoctrineoffluxions:
  itisnoneofthatanalysiswithwhichIamconcerned。ThatIamfarfromquarrellingatapproximationsingeometryismanifestfromthethirty—thirdandfifty—thirdqueriesinthe`Analyst。’Andthatthemethodoffluxionspretendstosomewhatmorethanthemethodofindivisiblesisplain;becauseSirIsaacdisclaimsthismethodasnotgeometrical。[SeetheScholiumattheendofthefirstsection。Lib。i。,`Phil。Nat。Princip。Math。’]Andthatthemethodoffluxionsissupposedaccurateingeometricalrigourismanifesttowhoeverconsiderswhatthegreatauthorwritesaboutit;
  especiallyinhis`IntroductiontotheQuadratureofCurves,’wherehesaith,Inrebusmathematiciserroresquamminiminonsuntcontemnendi。
  Whichexpressionyouhaveseenquotedinthe`Analyst,’andyetyouseemignorantthereof,andindeedoftheveryendanddesignofthegreatauthorofthishisinventionoffluxions。
  26。Asoftasyoutalkoffinitequantitiesinconsiderableinpractice,SirIsaacNewtondisownsyourapology。Cave,saithhe,intellexerisfinitas。And,althoughquantitieslessthansensiblemaybeofnoaccountinpractice,yetnoneofyourmasters,notwillevenyouyourself,venturetosaythattheyareofnoaccountintheoryandinreasoning。Theapplicationingrosspracticeisnotthepointquestioned,buttherigourandjustnessofthereasoning。Anditisevidentthat,bethesubjecteversolittle,oreversoinconsiderable,thisdothnothinderbutthatapersontreatingthereofmaycommitverygreaterrorsinlogic;
  whichlogicalerrorsareinnowisetobemeasuredbythesensibleorpracticalinconveniencesthencearising,which,perchance,maybenoneatall。Itmustbeownedthat,afteryouhavemisledandamusedyourlessqualifiedreader(asyoucallhim),youreturntotherealpointincontroversy,andsetyourselftojustifySirIsaac’smethodofgettingridoftheabove—mentionedrectangle。AndhereImustintreatthereadertoobservehowfairlyyouproceed。
  27。Firstthenyouaffirm(p。44),``thatneitherinthedemonstrationoftheruleforfindingthefluxionoftherectangleoftwoflowingquantities,norinanythingprecedingorfollowingit,isanymention,somuchasonce,madeoftheincrementoftherectangleofsuchflowingquantities。’’NowIaffirmthedirectcontrary。For,intheverypassagebyyouquotedinthissamepage,fromthefirstcaseofthesecondlemmaofthesecondbookofSirIsaac’sPrinciples,beginningwithRectangulumquodvismotuperpetuoauctum,andendingwithigiturlaterumincrementistotisaandbgeneraturrectanguliincrementumaB
  bA。Q。E。D。inthisverypassage,Isay,isexpressmentionmadeoftheincrementofsuchrectangle。Asthisismatteroffact,Ireferittothereader’sowneyes。Ofwhatrectanglehaveweheretheincrement?
  Isitnotplainlyofthatwhosesideshaveaandbfortheirincrementatota,thatis,ofAB。Letanyreaderjudgewhetheritbenotplainfromthewords,thesense,andthecontext,thatthegreatauthorintheendofhisdemonstrationunderstandshisincrementumasbelongingtotherectangulumquodvisatthebeginning。Isnotthesamealsoevidentfromtheverylemmaitselfprefixedtothedemonstration?
  Thesensewhereofis(astheauthorthereexplainsit),thatifthemomentsoftheflowingquantitiesAandBarecalledaandb,thenthemomentumvelmutatiogenitirectanguliABwillbeaBbA。Eitherthereforetheconclusionofthedemonstrationisnotthethingwhichwastobedemonstrated,ortherectanguliincrementumaBbAbelongstotherectangleAB。
  28。Allthisissoplainthatnothingcanbemoreso;andyetyouwouldfainperplexthisplaincasebydistinguishingbetweenanincrementandamoment。Butitisevidenttoeveryonewhohasanynotionofdemonstrationthattheincrementumintheconclusionmustbethemomentuminthelemma;andtosupposeitotherwiseisnocredittotheauthor。Itisineffectsupposinghimtobeonewhodidnotknowwhathewoulddemonstrate。ButletushearSirIsaac’sownwords:Earum(quantitatumscilicetfluentium)incrementaveldecrementamomentaneasubnominemomentorumintelligo。Andyouobserveyourselfthatheuseththewordmomenttosignifyeitheranincrementordecrement。Hence,withanintentiontopuzzleme,youproposetheincrementanddecrementofAB,andaswhichoftheseIwouldcallthemoment?Thecaseyousayisdifficult。Myanswerisveryplainandeasy,towit,Eitherofthem。
  You,indeed,makeadifferentanswer;andfromtheauthor’ssayingthatbyamomentheunderstandseitherthemomentaneousincrementordecrementoftheflowingquantities,youwouldhaveusconclude,byaverywonderfulinference,thathismomentisneithertheincrementnordecrementthereof。
  Woulditnotbeasgoodaninference,becauseanumberiseitheroddoreven,toconcludeitisneither?Cananyonemakesenseofthis?Orcanevenyourselfhopethatthiswillgodownwiththereader,howlittlesoeverqualified?Itmustbeowned,youendeavourtointrudethisinferenceonhim,ratherbymirthandhumourthanbyreasoning。Youraremerry,Isay,and(p。46)representthetwomathematicalquantitiesaspleadingtheirrights,astossingupcrossandpile,asdisputingamicably。Youtalkoftheirclaimingpreference,theiragreeing,theirboyishness,andtheirgravity。Andafterthisingeniousdigressionyouaddressmeinthefollowingwords—Believeme,thereisnoremedy,youmustacquiesce。ButmyansweristhatIwillneitherbelieveyounoracquiesce;thereisaplainremedyincommonsense;and,topreventsurprise,Idesirethereaderalwaystokeepthecontrovertedpointinview,toexamineyourreasons,andbecautioushowhetakesyourword,butmostofallwhenyouarepositive,oreloquent,ormerry。
  29。Apageortwoafter,youverycandidlyrepresentyourcasetobethatofanassbetweentwobottlesofhay:itisyourownexpression。ThecauseofyourperplexityisthatyouknownotwhetherthevelocityofABincreasing,orofABdecreasingistobeesteemedthefluxion,orproportionaltothemomentoftherectangle。Myownopinion,agreeablytowhathathbeenpremised,isthateithermaybedeemedthefluxion。Butyoutellus(p。49)``thatyouthink,thevenerableghostofSirIsaacNewtonwhispersyou,thevelocityyouseekforisneithertheonenortheotherofthese,butitisthevelocitywhichtheflowingrectanglehathnotwhileitisgreaterorlessthanAB,butatthatveryinstantoftimethatitisAB。’’Formypart,intherectangleABconsideredsimplyinitself,withouteitherincreasingordiminishing,Icanconceivenovelocityatall。Andifthereaderisofmyownmind,hewillnottakeeitheryourword,oreventhewordofaghost,howvenerablesoever,forvelocitywithoutmotion。Youproceedandtellusthat,inlikemanner,themomentoftherectangleisneitheritsincrementordecrement。
  Thisyouwouldhaveusbelieveontheauthorityofhisghost,indirectoppositiontowhatSirIsaachimselfassertedwhenalive。Incrementa(saithhe)veldecrementamomentaneasubnominemomentorumintelligo:
  itautincrementapromomentisaddititiisseuaffirmativis,acdecrementaprosubductitiisseunegativishabeantur。[`Princip。Phil。Nat。,’lib。
  ii,lem。ii。]Iwillnotinyourstylebidthereaderbelieveme,butbelievehiseyes。
  30。Tomeitverilyseemsthatyouhaveundertakenthedefenceofwhatyoudonotunderstand。Tomendthematter,yousay,``youdonotconsiderABaslyingateitherextremityofthemoment,butasextendedtothemiddleofit;ashavingacquiredtheonehalfofthemoment,andasbeingabouttoacquiretheother;orashavinglostonehalfofit,andbeingabouttolosetheother。’’Now,inthenameoftruth,Ientreatyoutotellwhatthismomentis,tothemiddlewhereoftherectangleisextended?Thismoment,Isay,whichisacquired,whichislost,whichiscutintwo,ordistinguishedintohalves?Isitafinitequantity,oraninfinitesimal,oramerelimit,ornothingatall?Takeitinwhatsenseyouwill,Icannotmakeyourdefenceeitherconsistentorintelligible。For,ifyoutakeitineitherofthetwoformersenses,youcontradictSirIsaacNewton。And,ifyoutakeitineitherofthelatter,youcontradictcommonsense;itbeingplain,thatwhathathnomagnitude,orisnoquantity,cannotbedivided。AndhereImustentreatthereadertopreservehisfullfreedomofmindentire,andnotweaklysufferhisjudgementtobeoverbornebyyourimaginationandyourprejudices,bygreatnamesandauthorities,byghostsandvisions,andaboveallbythatextremesatisfactionandcomplacencywithwhichyouutteryourstrangeconceits;
  ifwordswithoutameaningmaybecalledso。Afteryouhavegiventhisunintelligibleaccount,youaskwithyouraccustomedair,``Whatsayyou,Sir?IsthisajustandlegitimatereasonforSirIsaac’sproceedingashedid?Ithinkyoumustacknowledgeittobeso。’’But,alas!Iacknowledgenosuchthing。Ifindnosenseorreasoninwhatyousay。Letthereaderfinditifhecan。
  31。Inthenextplace(p。50),youchargemewithwantofcaution。``Inasmuch(sayyou)asthatquantitywhichSirIsaacNewton,throughhiswholelemma,andalltheseveralcasesofit,constantlycallsamoment,withoutconfiningittobeeitheranincrementordecrement,isbyyouinconsideratelyandarbitrarily,andwithoutanyshadowofreasongiven,supposedanddeterminedtobeanincrement。’’TowhichchargeIreply,thatitisasuntrueasitisperemptory。Forthat,intheforegoingcitationfromthefirstcaseofSirIsaac’slemma,heexpresslydeterminesittobeanincrement。And,asthisparticularinstanceorpassagewasthatwhichIobjectedto,itwasreasonableandproperformetoconsiderthemomentinthesamelight。But,takeitincrementordecrementasyouwill,theobjectionsstilllie,andthedifficultiesareequallyinsuperable。
  Youthenproceedtoextolthegreatauthorofthefluxionarymethod,andtobestowsomebrusqueriesuponthosewhounadvisedlydaretodifferfromhim。ToallwhichIshallgivenoanswer。
  32。Afterwardstoremove(asyousay)allscrupleanddifficultyaboutthisaffair,youobservethatthemomentoftherectangledeterminedbySirIsaacNewton,andtheincrementoftherectangledeterminedbymeareperfectlyandexactlyequal,supposingaandbtobediminishedadinfinitum:and,forproofofthis,yourefertothefirstlemmaofthefirstsectionofthefirstbookofSirIsaac’sprinciples。Ianswerthatifaandbarerealquantitiesthenabissomething,andconsequentlymakesarealdifference:
  butiftheyarenothing,thentherectangleswhereoftheyarecoefficientsbecomenothinglikewise:andconsequentlythemomentumorincrementum,whetherSirIsaac’sormine,areinthatcasenothingatall。Asfortheabove—mentionedlemma,whichyoureferto,andwhichyouwishIhadconsultedsooner,bothformyownsakeandforyours;ItellyouIhadlongsinceconsultedandconsideredit。ButIverymuchdoubtwhetheryouhavesufficientlyconsideredthatlemma,itsdemonstration,anditsconsequences。For,howeverthatwayofreasoningmaydointhemethodofexhaustions,wherequantitieslessthanassignableareregardedasnothing:yet,forafluxionistwritingaboutmomentumstoarguethatquantitiesmustbeequalbecausetheyhavenoassignabledifferenceseemsthemostinjudiciousstepthatcouldbetaken:itisdirectlydemolishingtheverydoctrineyouwoulddefend。For,itwillthencefollowthatallhomogeneousmomentumsareequal,andconsequentlythevelocities,mutations,orfluxions,proportionalthereto,arealllikewiseequal。Thereis,therefore,onlyoneproportionofequalitythroughout,whichatonceoverthrowsthewholesystemyouundertaketodefend。Yourmoments(Isay)notbeingthemselvesassignablequantities,theirdifferencescannotbeassignable:and,ifthisbetrue,bythatwayofreasoningitwillfollow,theyareallequal;uponwhichsuppositionyoucannotmakeonestepinthemethodoffluxions。Itappearsfromhence,howunjustlyyoublameme(p。32)foromittingtogiveanyaccountofthatfirstsectionofthefirstbookofthe`Principia,’wherein(yousay)thefoundationofthemethodoffluxionsisgeometricallydemonstratedandlargelyexplained,anddifficultiesandobjectionsagainstitareclearlysolved。Allwhichissofarfrombeingtruethattheveryfirstandfundamentallemmaofthatsectionisincompatiblewithandsubversiveofthedoctrineoffluxions。And,indeed,whoseesnotthatademonstrationadabsurdummoreveterum,proceedingonasuppositionthateverydifferencemustbesomegivenquantity,cannotbeadmittedin,orconsistwith,amethodwhereinquantities,lessthananygiven,aresupposedreallytoexist,andbecapableofdivision?
  33。Thenextpointyouundertaketodefendisthatmethodforobtainingaruletofindthefluxionofanypowerofaflowingquantity,whichisdeliveredinhis`IntroductiontotheQuadratures,’