METAPHYSICS

第44章

Forjustastheuniversalpropositionsofmathematicsdealnot

withobjectswhichexistseparately,apartfromextendedmagnitudes

andfromnumbers,butwithmagnitudesandnumbers,nothoweverqua

suchastohavemagnitudeortobedivisible,clearlyitispossible

thatthereshouldalsobebothpropositionsanddemonstrationsabout

sensiblemagnitudes,nothoweverquasensiblebutquapossessedof

certaindefinitequalities。Forastherearemanypropositionsabout

thingsmerelyconsideredasinmotion,apartfromwhateachsuchthing

isandfromtheiraccidents,andasitisnotthereforenecessarythat

thereshouldbeeitheramobileseparatefromsensibles,oradistinct

mobileentityinthesensibles,sotoointhecaseofmobilesthere

willbepropositionsandsciences,whichtreatthemhowevernotqua

mobilebutonlyquabodies,oragainonlyquaplanes,oronlyqua

lines,orquadivisibles,orquaindivisibleshavingposition,oronly

quaindivisibles。Thussinceitistruetosaywithoutqualification

thatnotonlythingswhichareseparablebutalsothingswhichare

inseparableexist(forinstance,thatmobilesexist),itistrue

alsotosaywithoutqualificationthattheobjectsofmathematics

exist,andwiththecharacterascribedtothembymathematicians。

Andasitistruetosayoftheothersciencestoo,without

qualification,thattheydealwithsuchandsuchasubject-notwith

whatisaccidentaltoit(e。g。notwiththepale,ifthehealthything

ispale,andthesciencehasthehealthyasitssubject),butwith

thatwhichisthesubjectofeachscience-withthehealthyifit

treatsitsobjectquahealthy,withmanifquaman:-sotooisit

withgeometry;ifitssubjectshappentobesensible,thoughitdoes

nottreatthemquasensible,themathematicalscienceswillnotfor

thatreasonbesciencesofsensibles-nor,ontheotherhand,of

otherthingsseparatefromsensibles。Manypropertiesattachtothings

invirtueoftheirownnatureaspossessedofeachsuchcharacter;

e。g。thereareattributespeculiartotheanimalquafemaleorqua

male(yetthereisno’female’nor’male’separatefromanimals);so

thattherearealsoattributeswhichbelongtothingsmerelyas

lengthsorasplanes。Andinproportionaswearedealingwith

thingswhicharepriorindefinitionandsimpler,ourknowledgehas

moreaccuracy,i。e。simplicity。Thereforeasciencewhichabstracts

fromspatialmagnitudeismoreprecisethanonewhichtakesitinto

account;andascienceismostpreciseifitabstractsfrom

movement,butifittakesaccountofmovement,itismostpreciseif

itdealswiththeprimarymovement,forthisisthesimplest;andof

thisagainuniformmovementisthesimplestform。

Thesameaccountmaybegivenofharmonicsandoptics;forneither

considersitsobjectsquasightorquavoice,butqualinesand

numbers;butthelatterareattributespropertotheformer。And

mechanicstooproceedsinthesameway。Thereforeifwesuppose

attributesseparatedfromtheirfellowattributesandmakeanyinquiry

concerningthemassuch,weshallnotforthisreasonbeinerror,any

morethanwhenonedrawsalineonthegroundandcallsitafootlong

whenitisnot;fortheerrorisnotincludedinthepremisses。

Eachquestionwillbebestinvestigatedinthisway-bysetting

upbyanactofseparationwhatisnotseparate,asthe

arithmeticianandthegeometerdo。Foramanquamanisone

indivisiblething;andthearithmeticiansupposedoneindivisible

thing,andthenconsideredwhetheranyattributebelongstoaman

quaindivisible。Butthegeometertreatshimneitherquamannorqua

indivisible,butasasolid。Forevidentlythepropertieswhich

wouldhavebelongedtohimevenifperchancehehadnotbeen

indivisible,canbelongtohimevenapartfromtheseattributes。Thus,

then,geometersspeak

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