Sincetherewerethreekindsofsubstance，twoofthemphysical
　　andoneunmovable，regardingthelatterwemustassertthatitis
　　necessarythatthereshouldbeaneternalunmovablesubstance。For
　　substancesarethefirstofexistingthings，andiftheyareall
　　destructible，allthingsaredestructible。Butitisimpossiblethat
　　movementshouldeitherhavecomeintobeingorceasetobeforit
　　mustalwayshaveexisted，orthattimeshould。Fortherecouldnotbe
　　abeforeandanafteriftimedidnotexist。Movementalsois
　　continuous，then，inthesenseinwhichtimeis；fortimeiseither
　　thesamethingasmovementoranattributeofmovement。Andthereis
　　nocontinuousmovementexceptmovementinplace，andofthisonlythat
　　whichiscirculariscontinuous。
　　Butifthereissomethingwhichiscapableofmovingthingsor
　　actingonthem，butisnotactuallydoingso，therewillnot
　　necessarilybemovement；forthatwhichhasapotencyneednot
　　exerciseit。Nothing，then，isgainedevenifwesupposeeternal
　　substances，asthebelieversintheFormsdo，unlessthereistobein
　　themsomeprinciplewhichcancausechange；nay，eventhisisnot
　　enough，norisanothersubstancebesidestheFormsenough；forifit
　　isnottoact，therewillbenomovement。Furtherevenifitacts，
　　thiswillnotbeenough，ifitsessenceispotency；fortherewillnot
　　beeternalmovement，sincethatwhichispotentiallymaypossibly
　　notbe。Theremust，then，besuchaprinciple，whoseveryessenceis
　　actuality。Further，then，thesesubstancesmustbewithoutmatter；for
　　theymustbeeternal，ifanythingiseternal。Thereforetheymustbe
　　actuality。
　　Yetthereisadifficulty；foritisthoughtthateverything
　　thatactsisabletoact，butthatnoteverythingthatisableto
　　actacts，sothatthepotencyisprior。Butifthisisso，nothing
　　thatisneedbe；foritispossibleforallthingstobecapableof
　　existingbutnotyettoexist。
　　Yetifwefollowthetheologianswhogeneratetheworldfrom
　　night，orthenaturalphilosopherswhosaythat’allthingswere
　　together’，thesameimpossibleresultensues。Forhowwilltherebe
　　movement，ifthereisnoactuallyexistingcause？Woodwillsurelynot
　　moveitself-thecarpenter’sartmustactonit；norwillthemenstrual
　　bloodnortheearthsetthemselvesinmotion，buttheseedsmustact
　　ontheearthandthesemenonthemenstrualblood。
　　Thisiswhysomesupposeeternalactuality-e。g。Leucippusand
　　Plato；fortheysaythereisalwaysmovement。Butwhyandwhatthis
　　movementistheydosay，nor，iftheworldmovesinthiswayor
　　that，dotheytellusthecauseofitsdoingso。Nownothingis
　　movedatrandom，buttheremustalwaysbesomethingpresenttomove
　　it；e。g。asamatteroffactathingmovesinonewaybynature，and
　　inanotherbyforceorthroughtheinfluenceofreasonorsomething
　　else。Further，whatsortofmovementisprimary？Thismakesavast
　　difference。ButagainforPlato，atleast，itisnotpermissibleto
　　nameherethatwhichhesometimessupposestobethesourceof
　　movement-thatwhichmovesitself；forthesoulislater，andcoeval
　　withtheheavens，accordingtohisaccount。Tosupposepotencyprior
　　toactuality，then，isinasenseright，andinasensenot；andwe
　　havespecifiedthesesenses。Thatactualityisprioristestifiedby
　　Anaxagorasforhis’reason’isactualityandbyEmpedoclesinhis
　　doctrineofloveandstrife，andbythosewhosaythatthereisalways
　　movement，e。g。Leucippus。Thereforechaosornightdidnotexistfor
　　aninfinitetime，butthesamethingshavealwaysexistedeither
　　passingthroughacycleofchangesorobeyingsomeotherlaw，since
　　actualityispriortopotency。If，then，thereisaconstantcycle，
　　somethingmustalwaysremain，actinginthesameway。Andifthere
　　istobegenerationanddestruction，theremustbesomethingelse
　　whichisalwaysactingindifferentways。Thismust，then，actin
　　onewayinvirtueofitself，andinanotherinvirtueofsomething
　　else-eitherofathirdagent，therefore，orofthefirst。Nowit
　　mustbeinvirtueofthefirst。Forotherwisethisagaincausesthe
　　motionbothofthesecondagentandofthethird。Thereforeitis
　　bettertosay’thefirst’。Foritwasthecauseofeternaluniformity；
　　andsomethingelseisthecauseofvariety，andevidentlyboth
　　togetherarethecauseofeternalvariety。This，accordingly，isthe
　　characterwhichthemotionsactuallyexhibit。Whatneedthenis
　　theretoseekforotherprinciples？
　　Since1thisisapossibleaccountofthematter，and2if
　　itwerenottrue，theworldwouldhaveproceededoutofnightand’all
　　thingstogether’andoutofnon-being，thesedifficultiesmaybetaken
　　assolved。Thereis，then，somethingwhichisalwaysmovedwithan
　　unceasingmotion，whichismotioninacircle；andthisisplainnot
　　intheoryonlybutinfact。Thereforethefirstheavenmustbe
　　eternal。Thereisthereforealsosomethingwhichmovesit。Andsince
　　thatwhichmovesandismovedisintermediate，thereissomething
　　whichmoveswithoutbeingmoved，beingeternal，substance，and
　　actuality。Andtheobjectofdesireandtheobjectofthoughtmove
　　inthisway；theymovewithoutbeingmoved。Theprimaryobjectsof
　　desireandofthoughtarethesame。Fortheapparentgoodisthe
　　objectofappetite，andtherealgoodistheprimaryobjectof
　　rationalwish。Butdesireisconsequentonopinionratherthanopinion
　　ondesire；forthethinkingisthestarting-point。Andthoughtis
　　movedbytheobjectofthought，andoneofthetwocolumnsof
　　oppositesisinitselftheobjectofthought；andinthis，substance
　　isfirst，andinsubstance，thatwhichissimpleandexists
　　actually。Theoneandthesimplearenotthesame；for’one’means
　　ameasure，but’simple’meansthatthethingitselfhasacertain
　　nature。Butthebeautiful，also，andthatwhichisinitself
　　desirableareinthesamecolumn；andthefirstinanyclassisalways
　　best，oranalogoustothebest。
　　Thatafinalcausemayexistamongunchangeableentitiesis
　　shownbythedistinctionofitsmeanings。Forthefinalcauseisa
　　somebeingforwhosegoodanactionisdone，andbsomethingat
　　whichtheactionaims；andofthesethelatterexistsamong
　　unchangeableentitiesthoughtheformerdoesnot。Thefinalcause，
　　then，producesmotionasbeingloved，butallotherthingsmoveby
　　beingmoved。Nowifsomethingismoveditiscapableofbeing
　　otherwisethanasitis。Thereforeifitsactualityistheprimary
　　formofspatialmotion，theninsofarasitissubjecttochange，
　　inthisrespectitiscapableofbeingotherwise，-inplace，evenif
　　notinsubstance。Butsincethereissomethingwhichmoveswhile
　　itselfunmoved，existingactually，thiscaninnowaybeotherwise
　　thanasitis。Formotioninspaceisthefirstofthekindsof
　　change，andmotioninacirclethefirstkindofspatialmotion；and
　　thisthefirstmoverproduces。Thefirstmover，then，existsof
　　necessity；andinsofarasitexistsbynecessity，itsmodeof
　　beingisgood，anditisinthissenseafirstprinciple。Forthe
　　necessaryhasallthesesenses-thatwhichisnecessaryperforce
　　becauseitiscontrarytothenaturalimpulse，thatwithoutwhich
　　thegoodisimpossible，andthatwhichcannotbeotherwisebutcan
　　existonlyinasingleway。
　　Onsuchaprinciple，then，dependtheheavensandtheworldof
　　nature。Anditisalifesuchasthebestwhichweenjoy，andenjoy
　　forbutashorttimeforitiseverinthisstate，whichwecannot
　　be，sinceitsactualityisalsopleasure。Andforthisreasonare
　　waking，perception，andthinkingmostpleasant，andhopesandmemories
　　aresoonaccountofthese。Andthinkinginitselfdealswiththat
　　whichisbestinitself，andthatwhichisthinkinginthefullest
　　sensewiththatwhichisbestinthefullestsense。Andthoughtthinks
　　onitselfbecauseitsharesthenatureoftheobjectofthought；for
　　itbecomesanobjectofthoughtincomingintocontactwithand
　　thinkingitsobjects，sothatthoughtandobjectofthoughtarethe
　　same。Forthatwhichiscapableofreceivingtheobjectofthought，
　　i。e。theessence，isthought。Butitisactivewhenitpossesses
　　thisobject。Thereforethepossessionratherthanthereceptivityis
　　thedivineelementwhichthoughtseemstocontain，andtheactof
　　contemplationiswhatismostpleasantandbest。If，then，Godis
　　alwaysinthatgoodstateinwhichwesometimesare，thiscompels
　　ourwonder；andifinabetterthiscompelsityetmore。AndGodisin
　　abetterstate。AndlifealsobelongstoGod；fortheactualityof
　　thoughtislife，andGodisthatactuality；andGod’sself-dependent
　　actualityislifemostgoodandeternal。WesaythereforethatGod
　　isalivingbeing，eternal，mostgood，sothatlifeandduration
　　continuousandeternalbelongtoGod；forthisisGod。
　　Thosewhosuppose，asthePythagoreansandSpeusippusdo，that
　　supremebeautyandgoodnessarenotpresentinthebeginning，
　　becausethebeginningsbothofplantsandofanimalsarecauses，but
　　beautyandcompletenessareintheeffectsofthese，arewrongin
　　theiropinion。Fortheseedcomesfromotherindividualswhichare
　　priorandcomplete，andthefirstthingisnotseedbutthecomplete
　　being；e。g。wemustsaythatbeforetheseedthereisaman，-notthe
　　manproducedfromtheseed，butanotherfromwhomtheseedcomes。
　　Itisclearthenfromwhathasbeensaidthatthereisasubstance
　　whichiseternalandunmovableandseparatefromsensiblethings。It
　　hasbeenshownalsothatthissubstancecannothaveanymagnitude，but
　　iswithoutpartsandindivisibleforitproducesmovementthrough
　　infinitetime，butnothingfinitehasinfinitepower；and，whileevery
　　magnitudeiseitherinfiniteorfinite，itcannot，fortheabove
　　reason，havefinitemagnitude，anditcannothaveinfinitemagnitude
　　becausethereisnoinfinitemagnitudeatall。Butithasalsobeen
　　shownthatitisimpassiveandunalterable；foralltheother
　　changesareposteriortochangeofplace。
　　Itisclear，then，whythesethingsareastheyare。Butwemust
　　notignorethequestionwhetherwehavetosupposeonesuch
　　substanceormorethanone，andifthelatter，howmany；wemust
　　alsomention，regardingtheopinionsexpressedbyothers，thatthey
　　havesaidnothingaboutthenumberofthesubstancesthatcaneven
　　beclearlystated。ForthetheoryofIdeashasnospecialdiscussion
　　ofthesubject；forthosewhospeakofIdeassaytheIdeasare
　　numbers，andtheyspeakofnumbersnowasunlimited，nowaslimitedby
　　thenumber10；butasforthereasonwhythereshouldbejustso
　　manynumbers，nothingissaidwithanydemonstrativeexactness。We
　　howevermustdiscussthesubject，startingfromthepresuppositions
　　anddistinctionswehavementioned。Thefirstprincipleorprimary
　　beingisnotmovableeitherinitselforaccidentally，butproduces
　　theprimaryeternalandsinglemovement。Butsincethatwhichismoved
　　mustbemovedbysomething，andthefirstmovermustbeinitself
　　unmovable，andeternalmovementmustbeproducedbysomething
　　eternalandasinglemovementbyasinglething，andsinceweseethat
　　besidesthesimplespatialmovementoftheuniverse，whichwesay
　　thefirstandunmovablesubstanceproduces，thereareotherspatial
　　movements-thoseoftheplanets-whichareeternalforabodywhich
　　movesinacircleiseternalandunresting；wehaveprovedthese
　　pointsinthephysicaltreatises，eachofthesemovementsalsomust
　　becausedbyasubstancebothunmovableinitselfandeternal。Forthe
　　natureofthestarsiseternaljustbecauseitisacertainkindof
　　substance，andthemoveriseternalandpriortothemoved，andthat
　　whichispriortoasubstancemustbeasubstance。Evidently，then，
　　theremustbesubstanceswhichareofthesamenumberasthemovements
　　ofthestars，andintheirnatureeternal，andinthemselves
　　unmovable，andwithoutmagnitude，forthereasonbeforementioned。
　　Thatthemoversaresubstances，then，andthatoneoftheseisfirst
　　andanothersecondaccordingtothesameorderasthemovementsofthe
　　stars，isevident。Butinthenumberofthemovementswereacha
　　problemwhichmustbetreatedfromthestandpointofthatoneofthe
　　mathematicalscienceswhichismostakintophilosophy-viz。of
　　astronomy；forthissciencespeculatesaboutsubstancewhichis
　　perceptiblebuteternal，buttheothermathematicalsciences，i。e。
　　arithmeticandgeometry，treatofnosubstance。Thatthemovementsare
　　morenumerousthanthebodiesthataremovedisevidenttothosewho
　　havegivenevenmoderateattentiontothematter；foreachofthe
　　planetshasmorethanonemovement。Butastotheactualnumberof
　　thesemovements，wenow-togivesomenotionofthesubject-quote
　　whatsomeofthemathematicianssay，thatourthoughtmayhavesome
　　definitenumbertograsp；but，fortherest，wemustpartly
　　investigateforourselves，Partlylearnfromotherinvestigators，
　　andifthosewhostudythissubjectformanopinioncontrarytowhat
　　wehavenowstated，wemustesteembothpartiesindeed，butfollowthe
　　moreaccurate。