首页 >出版文学> Physics>第3章

第3章

  2
  WemaydistinguishgenerallybetweenpredicatingBofAbecauseitAisitself,andbecauseitissomethingelse;andparticularlybetweenplacewhichiscommonandinwhichallbodiesare,andthespecialplaceoccupiedprimarilybyeach。Imean,forinstance,thatyouarenowintheheavensbecauseyouareintheairanditisintheheavens;andyouareintheairbecauseyouareontheearth;andsimilarlyontheearthbecauseyouareinthisplacewhichcontainsnomorethanyou。
  Nowifplaceiswhatprimarilycontainseachbody,itwouldbealimit,sothattheplacewouldbetheformorshapeofeachbodybywhichthemagnitudeorthematterofthemagnitudeisdefined:forthisisthelimitofeachbody。
  If,then,welookatthequestioninthiswaytheplaceofathingisitsform。But,ifweregardtheplaceastheextensionofthemagnitude,itisthematter。Forthisisdifferentfromthemagnitude:
  itiswhatiscontainedanddefinedbytheform,asbyaboundingplane。Matterortheindeterminateisofthisnature;whentheboundaryandattributesofaspherearetakenaway,nothingbutthematterisleft。
  ThisiswhyPlatointheTimaeussaysthatmatterandspacearethesame;forthe'participant'andspaceareidentical。Itistrue,indeed,thattheaccounthegivesthereofthe'participant'
  isdifferentfromwhathesaysinhisso-called'unwrittenteaching'。Nevertheless,hedididentifyplaceandspace。ImentionPlatobecause,whileallholdplacetobesomething,healonetriedtosaywhatitis。
  Inviewofthesefactsweshouldnaturallyexpecttofinddifficultyindeterminingwhatplaceis,ifindeeditisoneofthesetwothings,matterorform。Theydemandaveryclosescrutiny,especiallyasitisnoteasytorecognizethemapart。
  Butitisatanyratenotdifficulttoseethatplacecannotbeeitherofthem。Theformandthematterarenotseparatefromthething,whereastheplacecanbeseparated。Aswepointedout,whereairwas,waterinturncomestobe,theonereplacingtheother;andsimilarlywithotherbodies。Hencetheplaceofathingisneitherapartnorastateofit,butisseparablefromit。Forplaceissupposedtobesomethinglikeavessel-thevesselbeingatransportableplace。Butthevesselisnopartofthething。
  Insofarthenasitisseparablefromthething,itisnottheform:quacontaining,itisdifferentfromthematter。
  Alsoitisheldthatwhatisanywhereisbothitselfsomethingandthatthereisadifferentthingoutsideit。Platoofcourse,ifwemaydigress,oughttotelluswhytheformandthenumbersarenotinplace,if'whatparticipates'isplace-whetherwhatparticipatesistheGreatandtheSmallorthematter,ashecalleditinwritingintheTimaeus。
  Further,howcouldabodybecarriedtoitsownplace,ifplacewasthematterortheform?Itisimpossiblethatwhathasnoreferencetomotionorthedistinctionofupanddowncanbeplace。Soplacemustbelookedforamongthingswhichhavethesecharacteristics。
  Iftheplaceisinthethingitmustbeifitiseithershapeormatterplacewillhaveaplace:forboththeformandtheindeterminateundergochangeandmotionalongwiththething,andarenotalwaysinthesameplace,butarewherethethingis。Hencetheplacewillhaveaplace。
  Further,whenwaterisproducedfromair,theplacehasbeendestroyed,fortheresultingbodyisnotinthesameplace。Whatsortofdestructionthenisthat?
  Thisconcludesmystatementofthereasonswhyspacemustbesomething,andagainofthedifficultiesthatmayberaisedaboutitsessentialnature。
  3
  Thenextstepwemusttakeistoseeinhowmanysensesonethingissaidtobe'in'another。
  1Asthefingeris'in'thehandandgenerallythepart'in'thewhole。
  2Asthewholeis'in'theparts:forthereisnowholeoverandabovetheparts。
  3Asmanis'in'animalandgenerallyspecies'in'genus。
  4Asthegenusis'in'thespeciesandgenerallythepartofthespecificform'in'thedefinitionofthespecificform。
  5Ashealthis'in'thehotandthecoldandgenerallytheform'in'thematter。
  6AstheaffairsofGreececentre'in'theking,andgenerallyeventscentre'in'theirprimarymotiveagent。
  7Astheexistenceofathingcentres'initsgoodandgenerally'in'itsend,i。e。in'thatforthesakeofwhich'itexists。
  8Inthestrictestsenseofall,asathingis'in'avessel,andgenerally'in'place。
  Onemightraisethequestionwhetherathingcanbeinitself,orwhethernothingcanbeinitself-everythingbeingeithernowhereorinsomethingelse。
  Thequestionisambiguous;wemaymeanthethingquaitselforquasomethingelse。
  Whentherearepartsofawhole-theonethatinwhichathingis,theotherthethingwhichisinit-thewholewillbedescribedasbeinginitself。Forathingisdescribedintermsofitsparts,aswellasintermsofthethingasawhole,e。g。amanissaidtobewhitebecausethevisiblesurfaceofhimiswhite,ortobescientificbecausehisthinkingfacultyhasbeentrained。Thejarthenwillnotbeinitselfandthewinewillnotbeinitself。Butthejarofwinewill:forthecontentsandthecontainerarebothpartsofthesamewhole。
  Inthissensethen,butnotprimarily,athingcanbeinitself,namely,as'white'isinbodyforthevisiblesurfaceisinbody,andscienceisinthemind。
  Itisfromthese,whichare'parts'inthesenseatleastofbeing'in'theman,thatthemaniscalledwhite,&c。Butthejarandthewineinseparationarenotpartsofawhole,thoughtogethertheyare。Sowhenthereareparts,athingwillbeinitself,as'white'isinmanbecauseitisinbody,andinbodybecauseitresidesinthevisiblesurface。Wecannotgofurtherandsaythatitisinsurfaceinvirtueofsomethingotherthanitself。Yetitisnotinitself:thoughtheseareinawaythesamething,theydifferinessence,eachhavingaspecialnatureandcapacity,'surface'and'white'。
  Thusifwelookatthematterinductivelywedonotfindanythingtobe'in'itselfinanyofthesensesthathavebeendistinguished;
  anditcanbeseenbyargumentthatitisimpossible。Foreachoftwothingswillhavetobeboth,e。g。thejarwillhavetobebothvesselandwine,andthewinebothwineandjar,ifitispossibleforathingtobeinitself;sothat,howevertrueitmightbethattheywereineachother,thejarwillreceivethewineinvirtuenotofitsbeingwinebutofthewine'sbeingwine,andthewinewillbeinthejarinvirtuenotofitsbeingajarbutofthejar'sbeingajar。Nowthattheyaredifferentinrespectoftheiressenceisevident;for'thatinwhichsomethingis'and'thatwhichisinit'wouldbedifferentlydefined。
  Norisitpossibleforathingtobeinitselfevenincidentally:
  fortwothingswouldatthesametimeinthesamething。Thejarwouldbeinitself-ifathingwhosenatureitistoreceivecanbeinitself;andthatwhichitreceives,namelyifwinewine,willbeinit。
  Obviouslythenathingcannotbeinitselfprimarily。
  Zeno'sproblem-thatifPlaceissomethingitmustbeinsomething-isnotdifficulttosolve。Thereisnothingtopreventthefirstplacefrombeing'in'somethingelse-notindeedinthatas'in'place,butashealthis'in'thehotasapositivedeterminationofitorasthehotis'in'bodyasanaffection。Soweescapetheinfiniteregress。
  Anotherthingisplain:sincethevesselisnopartofwhatisinitwhatcontainsinthestrictsenseisdifferentfromwhatiscontained,placecouldnotbeeitherthematterortheformofthethingcontained,butmustdifferent-forthelatter,boththematterandtheshape,arepartsofwhatiscontained。
  Thisthenmayserveasacriticalstatementofthedifficultiesinvolved。
  4
  Whatthenafterallisplace?Theanswertothisquestionmaybeelucidatedasfollows。
  Letustakeforgrantedaboutitthevariouscharacteristicswhicharesupposedcorrectlytobelongtoitessentially。Weassumethen-
  1Placeiswhatcontainsthatofwhichitistheplace。
  2Placeisnopartofthething。
  3Theimmediateplaceofathingisneitherlessnorgreaterthanthething。
  4Placecanbeleftbehindbythethingandisseparable。Inaddition:
  5Allplaceadmitsofthedistinctionofupanddown,andeachofthebodiesisnaturallycarriedtoitsappropriateplaceandreststhere,andthismakestheplaceeitherupordown。
  Havinglaidthesefoundations,wemustcompletethetheory。Weoughttotrytomakeourinvestigationsuchaswillrenderanaccountofplace,andwillnotonlysolvethedifficultiesconnectedwithit,butwillalsoshowthattheattributessupposedtobelongtoitdoreallybelongtoit,andfurtherwillmakeclearthecauseofthetroubleandofthedifficultiesaboutit。Suchisthemostsatisfactorykindofexposition。
  Firstthenwemustunderstandthatplacewouldnothavebeenthoughtof,iftherehadnotbeenaspecialkindofmotion,namelythatwithrespecttoplace。Itischieflyforthisreasonthatwesupposetheheavenalsotobeinplace,becauseitisinconstantmovement。Ofthiskindofchangetherearetwospecies-locomotionontheonehandand,ontheother,increaseanddiminution。Forthesetooinvolvevariationofplace:whatwastheninthisplacehasnowinturnchangedtowhatislargerorsmaller。
  Again,whenwesayathingis'moved',thepredicateeither1
  belongstoitactually,invirtueofitsownnature,or2invirtueofsomethingconjoinedwithit。Inthelattercaseitmaybeeitherasomethingwhichbyitsownnatureiscapableofbeingmoved,e。g。thepartsofthebodyorthenailintheship,orb
  somethingwhichisnotinitselfcapableofbeingmoved,butisalwaysmovedthroughitsconjunctionwithsomethingelse,as'whiteness'or'science'。Thesehavechangedtheirplaceonlybecausethesubjectstowhichtheybelongdoso。
  Wesaythatathingisintheworld,inthesenseofinplace,becauseitisintheair,andtheairisintheworld;andwhenwesayitisintheair,wedonotmeanitisineverypartoftheair,butthatitisintheairbecauseoftheoutersurfaceoftheairwhichsurroundsit;forifalltheairwereitsplace,theplaceofathingwouldnotbeequaltothething-whichitissupposedtobe,andwhichtheprimaryplaceinwhichathingisactuallyis。
  Whenwhatsurrounds,then,isnotseparatefromthething,butisincontinuitywithit,thethingissaidtobeinwhatsurroundsit,notinthesenseofinplace,butasapartinawhole。Butwhenthethingisseparateandincontact,itisimmediately'in'theinnersurfaceofthesurroundingbody,andthissurfaceisneitherapartofwhatisinitnoryetgreaterthanitsextension,butequaltoit;fortheextremitiesofthingswhichtoucharecoincident。
  Further,ifonebodyisincontinuitywithanother,itisnotmovedinthatbutwiththat。Ontheotherhanditismovedinthatifitisseparate。Itmakesnodifferencewhetherwhatcontainsismovedornot。
  Again,whenitisnotseparateitisdescribedasapartinawhole,asthepupilintheeyeorthehandinthebody:whenitisseparate,asthewaterinthecaskorthewineinthejar。Forthehandismovedwiththebodyandthewaterinthecask。
  Itwillnowbeplainfromtheseconsiderationswhatplaceis。
  Therearejustfourthingsofwhichplacemustbeone-theshape,orthematter,orsomesortofextensionbetweentheboundingsurfacesofthecontainingbody,orthisboundaryitselfifitcontainsnoextensionoverandabovethebulkofthebodywhichcomestobeinit。
  Threeoftheseitobviouslycannotbe:
  1Theshapeissupposedtobeplacebecauseitsurrounds,fortheextremitiesofwhatcontainsandofwhatiscontainedarecoincident。Boththeshapeandtheplace,itistrue,areboundaries。Butnotofthesamething:theformistheboundaryofthething,theplaceistheboundaryofthebodywhichcontainsit。
  2Theextensionbetweentheextremitiesisthoughttobesomething,becausewhatiscontainedandseparatemayoftenbechangedwhilethecontainerremainsthesameaswatermaybepouredfromavessel-theassumptionbeingthattheextensionissomethingoverandabovethebodydisplaced。Butthereisnosuchextension。Oneofthebodieswhichchangeplacesandarenaturallycapableofbeingincontactwiththecontainerfallsinwhicheveritmaychancetobe。
  Iftherewereanextensionwhichweresuchastoexistindependentlyandbepermanent,therewouldbeaninfinityofplacesinthesamething。Forwhenthewaterandtheairchangeplaces,alltheportionsofthetwotogetherwillplaythesamepartinthewholewhichwaspreviouslyplayedbyallthewaterinthevessel;atthesametimetheplacetoowillbeundergoingchange;sothattherewillbeanotherplacewhichistheplaceoftheplace,andmanyplaceswillbecoincident。Thereisnotadifferentplaceofthepart,inwhichitismoved,whenthewholevesselchangesitsplace:itisalwaysthesame:foritisintheproximateplacewheretheyarethattheairandthewaterorthepartsofthewatersucceedeachother,notinthatplaceinwhichtheycometobe,whichispartoftheplacewhichistheplaceofthewholeworld。
  3Thematter,too,mightseemtobeplace,atleastifweconsideritinwhatisatrestandisthusseparatebutincontinuity。Forjustasinchangeofqualitythereissomethingwhichwasformerlyblackandisnowwhite,orformerlysoftandnowhard-thisisjustwhywesaythatthematterexists-soplace,becauseitpresentsasimilarphenomenon,isthoughttoexist-onlyintheonecasewesaysobecausewhatwasairisnowwater,intheotherbecausewhereairformerlywasthereaisnowwater。Butthematter,aswesaidbefore,isneitherseparablefromthethingnorcontainsit,whereasplacehasbothcharacteristics。
  Well,then,ifplaceisnoneofthethree-neithertheformnorthematternoranextensionwhichisalwaysthere,differentfrom,andoverandabove,theextensionofthethingwhichisdisplaced-placenecessarilyistheoneofthefourwhichisleft,namely,theboundaryofthecontainingbodyatwhichitisincontactwiththecontainedbody。Bythecontainedbodyismeantwhatcanbemovedbywayoflocomotion。
  Placeisthoughttobesomethingimportantandhardtograsp,bothbecausethematterandtheshapepresentthemselvesalongwithit,andbecausethedisplacementofthebodythatismovedtakesplaceinastationarycontainer,foritseemspossiblethatthereshouldbeanintervalwhichisotherthanthebodieswhicharemoved。Theair,too,whichisthoughttobeincorporeal,contributessomethingtothebelief:itisnotonlytheboundariesofthevesselwhichseemtobeplace,butalsowhatisbetweenthem,regardedasempty。Just,infact,asthevesselistransportableplace,soplaceisanon-portablevessel。Sowhenwhatiswithinathingwhichismoved,ismovedandchangesitsplace,asaboatonariver,whatcontainsplaysthepartofavesselratherthanthatofplace。Placeontheotherhandisratherwhatismotionless:soitisratherthewholeriverthatisplace,becauseasawholeitismotionless。
  Henceweconcludethattheinnermostmotionlessboundaryofwhatcontainsisplace。
  Thisexplainswhythemiddleoftheheavenandthesurfacewhichfacesusoftherotatingsystemareheldtobe'up'and'down'inthestrictandfullestsenseforallmen:fortheoneisalwaysatrest,whiletheinnersideoftherotatingbodyremainsalwayscoincidentwithitself。Hencesincethelightiswhatisnaturallycarriedup,andtheheavywhatiscarrieddown,theboundarywhichcontainsinthedirectionofthemiddleoftheuniverse,andthemiddleitself,aredown,andthatwhichcontainsinthedirectionoftheoutermostpartoftheuniverse,andtheoutermostpartitself,areup。
  Forthisreason,too,placeisthoughttobeakindofsurface,andasitwereavessel,i。e。acontainerofthething。
  Further,placeiscoincidentwiththething,forboundariesarecoincidentwiththebounded。
  5
  Ifthenabodyhasanotherbodyoutsideitandcontainingit,itisinplace,andifnot,not。Thatiswhy,evenifthereweretobewaterwhichhadnotacontainer,thepartsofit,ontheonehand,willbemovedforonepartiscontainedinanother,while,ontheotherhand,thewholewillbemovedinonesense,butnotinanother。Forasawholeitdoesnotsimultaneouslychangeitsplace,thoughitwillbemovedinacircle:forthisplaceistheplaceofitsparts。Somethingsaremoved,notupanddown,butinacircle;
  othersupanddown,suchthingsnamelyasadmitofcondensationandrarefaction。
  Aswasexplained,somethingsarepotentiallyinplace,othersactually。So,whenyouhaveahomogeneoussubstancewhichiscontinuous,thepartsarepotentiallyinplace:whenthepartsareseparated,butincontact,likeaheap,theyareactuallyinplace。
  Again,1somethingsareperseinplace,namelyeverybodywhichismovableeitherbywayoflocomotionorbywayofincreaseispersesomewhere,buttheheaven,ashasbeensaid,isnotanywhereasawhole,norinanyplace,ifatleast,aswemustsuppose,nobodycontainsit。Onthelineonwhichitismoved,itspartshaveplace:
  foreachiscontiguousthenext。
  But2otherthingsareinplaceindirectly,throughsomethingconjoinedwiththem,asthesoulandtheheaven。Thelatteris,inaway,inplace,forallitspartsare:forontheorbonepartcontainsanother。Thatiswhytheupperpartismovedinacircle,whiletheAllisnotanywhere。Forwhatissomewhereisitselfsomething,andtheremustbealongsideitsomeotherthingwhereinitisandwhichcontainsit。ButalongsidetheAllortheWholethereisnothingoutsidetheAll,andforthisreasonallthingsareintheheaven;fortheheaven,wemaysay,istheAll。Yettheirplaceisnotthesameastheheaven。Itispartofit,theinnermostpartofit,whichisincontactwiththemovablebody;andforthisreasontheearthisinwater,andthisintheair,andtheairintheaether,andtheaetherinheaven,butwecannotgoonandsaythattheheavenisinanythingelse。
  Itisclear,too,fromtheseconsiderationsthatalltheproblemswhichwereraisedaboutplacewillbesolvedwhenitisexplainedinthisway:
  1Thereisnonecessitythattheplaceshouldgrowwiththebodyinit,2Northatapointshouldhaveaplace,3Northattwobodiesshouldbeinthesameplace,4Northatplaceshouldbeacorporealinterval:forwhatisbetweentheboundariesoftheplaceisanybodywhichmaychancetobethere,notanintervalinbody。
  Further,5placeisalsosomewhere,notinthesenseofbeinginaplace,butasthelimitisinthelimited;fornoteverythingthatisisinplace,butonlymovablebody。
  Also6itisreasonablethateachkindofbodyshouldbecarriedtoitsownplace。Forabodywhichisnextintheseriesandincontactnotbycompulsionisakin,andbodieswhichareuniteddonotaffecteachother,whilethosewhichareincontactinteractoneachother。
  Nor7isitwithoutreasonthateachshouldremainnaturallyinitsproperplace。Forthisparthasthesamerelationtoitsplace,asaseparableparttoitswhole,aswhenonemovesapartofwaterorair:so,too,airisrelatedtowater,fortheoneislikematter,theotherform-wateristhematterofair,airasitweretheactualityofwater,forwaterispotentiallyair,whileairispotentiallywater,thoughinanotherway。
  Thesedistinctionswillbedrawnmorecarefullylater。Onthepresentoccasionitwasnecessarytorefertothem:whathasnowbeenstatedobscurelywillthenbemademoreclear。Ifthematterandthefulfilmentarethesamethingforwaterisboth,theonepotentially,theothercompletely,waterwillberelatedtoairinawayasparttowhole。Thatiswhythesehavecontact:itisorganicunionwhenbothbecomeactuallyone。
  Thisconcludesmyaccountofplace-bothofitsexistenceandofitsnature。
  6
  Theinvestigationofsimilarquestionsaboutthevoid,also,mustbeheldtobelongtothephysicist-namelywhetheritexistsornot,andhowitexistsorwhatitis-justasaboutplace。Theviewstakenofitinvolveargumentsbothforandagainst,inmuchthesamesortofway。Forthosewhoholdthatthevoidexistsregarditasasortofplaceorvesselwhichissupposedtobe'full'whenitholdsthebulkwhichitiscapableofcontaining,'void'whenitisdeprivedofthat-asif'void'and'full'and'place'denotedthesamething,thoughtheessenceofthethreeisdifferent。
  Wemustbegintheinquirybyputtingdowntheaccountgivenbythosewhosaythatitexists,thentheaccountofthosewhosaythatitdoesnotexist,andthirdthecurrentviewonthesequestions。
  Thosewhotrytoshowthatthevoiddoesnotexistdonotdisprovewhatpeoplereallymeanbyit,butonlytheirerroneouswayofspeaking;thisistrueofAnaxagorasandofthosewhorefutetheexistenceofthevoidinthisway。Theymerelygiveaningeniousdemonstrationthatairissomething——bystrainingwine-skinsandshowingtheresistanceoftheair,andbycuttingitoffinclepsydras。Butpeoplereallymeanthatthereisanemptyintervalinwhichthereisnosensiblebody。Theyholdthateverythingwhichisinbodyisbodyandsaythatwhathasnothinginitatallisvoidsowhatisfullofairisvoid。Itisnotthentheexistenceofairthatneedstobeproved,butthenon-existenceofaninterval,differentfromthebodies,eitherseparableoractual-anintervalwhichdividesthewholebodysoastobreakitscontinuity,asDemocritusandLeucippushold,andmanyotherphysicists-orevenperhapsassomethingwhichisoutsidethewholebody,whichremainscontinuous。
  Thesepeople,then,havenotreachedeventhethresholdoftheproblem,butratherthosewhosaythatthevoidexists。
  1Theyargue,foronething,thatchangeinplacei。e。locomotionandincreasewouldnotbe。Foritismaintainedthatmotionwouldseemnottoexist,iftherewerenovoid,sincewhatisfullcannotcontainanythingmore。Ifitcould,andthereweretwobodiesinthesameplace,itwouldalsobetruethatanynumberofbodiescouldbetogether;foritisimpossibletodrawalineofdivisionbeyondwhichthestatementwouldbecomeuntrue。Ifthiswerepossible,itwouldfollowalsothatthesmallestbodywouldcontainthegreatest;for'manyalittlemakesamickle':thusifmanyequalbodiescanbetogether,soalsocanmanyunequalbodies。
  Melissus,indeed,infersfromtheseconsiderationsthattheAllisimmovable;forifitweremovedtheremust,hesays,bevoid,butvoidisnotamongthethingsthatexist。
  Thisargument,then,isonewayinwhichtheyshowthatthereisavoid。
  2Theyreasonfromthefactthatsomethingsareobservedtocontractandbecompressed,aspeoplesaythatacaskwillholdthewinewhichformerlyfilledit,alongwiththeskinsintowhichthewinehasbeendecanted,whichimpliesthatthecompressedbodycontractsintothevoidspresentinit。
  Again3increase,too,isthoughttotakealwaysbymeansofvoid,fornutrimentisbody,anditisimpossiblefortwobodiestobetogether。Aproofofthistheyfindalsoinwhathappenstoashes,whichabsorbasmuchwaterastheemptyvessel。
  ThePythagoreans,too,4heldthatvoidexistsandthatitenterstheheavenitself,whichasitwereinhalesit,fromtheinfiniteair。Furtheritisthevoidwhichdistinguishesthenaturesofthings,asifitwerelikewhatseparatesanddistinguishesthetermsofaseries。Thisholdsprimarilyinthenumbers,forthevoiddistinguishestheirnature。
  These,then,andsomany,arethemaingroundsonwhichpeoplehavearguedforandagainsttheexistenceofthevoid。
  7
  Asasteptowardssettlingwhichviewistrue,wemustdeterminethemeaningofthename。
  Thevoidisthoughttobeplacewithnothinginit。Thereasonforthisisthatpeopletakewhatexiststobebody,andholdthatwhileeverybodyisinplace,voidisplaceinwhichthereisnobody,sothatwherethereisnobody,theremustbevoid。
  Everybody,again,theysupposetobetangible;andofthisnatureiswhateverhasweightorlightness。
  Hence,byasyllogism,whathasnothingheavyorlightinit,isvoid。
  Thisresult,then,asIhavesaid,isreachedbysyllogism。Itwouldbeabsurdtosupposethatthepointisvoid;forthevoidmustbeplacewhichhasinitanintervalintangiblebody。
  Butatalleventsweobservethenthatinonewaythevoidisdescribedaswhatisnotfullofbodyperceptibletotouch;andwhathasheavinessandlightnessisperceptibletotouch。Sowewouldraisethequestion:whatwouldtheysayofanintervalthathascolourorsound-isitvoidornot?Clearlytheywouldreplythatifitcouldreceivewhatistangibleitwasvoid,andifnot,not。
  Inanotherwayvoidisthatinwhichthereisno'this'orcorporealsubstance。Sosomesaythatthevoidisthematterofthebodytheyidentifytheplace,too,withthis,andinthistheyspeakincorrectly;forthematterisnotseparablefromthethings,buttheyareinquiringaboutthevoidasaboutsomethingseparable。
  Sincewehavedeterminedthenatureofplace,andvoidmust,ifitexists,beplacedeprivedofbody,andwehavestatedbothinwhatsenseplaceexistsandinwhatsenseitdoesnot,itisplainthatonthisshowingvoiddoesnotexist,eitherunseparatedorseparated;thevoidismeanttobe,notbodybutratheranintervalinbody。Thisiswhythevoidisthoughttobesomething,viz。becauseplaceis,andforthesamereasons。Forthefactofmotioninrespectofplacecomestotheaidbothofthosewhomaintainthatplaceissomethingoverandabovethebodiesthatcometooccupyit,andofthosewhomaintainthatthevoidissomething。Theystatethatthevoidistheconditionofmovementinthesenseofthatinwhichmovementtakesplace;andthiswouldbethekindofthingthatsomesayplaceis。
  Butthereisnonecessityfortherebeingavoidifthereismovement。Itisnotintheleastneededasaconditionofmovementingeneral,forareasonwhich,incidentally,escapedMelissus;viz。
  thatthefullcansufferqualitativechange。
  Butnotevenmovementinrespectofplaceinvolvesavoid;forbodiesmaysimultaneouslymakeroomforoneanother,thoughthereisnointervalseparateandapartfromthebodiesthatareinmovement。
  Andthisisplainevenintherotationofcontinuousthings,asinthatofliquids。
  Andthingscanalsobecompressednotintoavoidbutbecausetheysqueezeoutwhatiscontainedinthemas,forinstance,whenwateriscompressedtheairwithinitissqueezedout;andthingscanincreaseinsizenotonlybytheentranceofsomethingbutalsobyqualitativechange;e。g。ifwaterweretobetransformedintoair。
  Ingeneral,boththeargumentaboutincreaseofsizeandthataboutwaterpouredontotheashesgetintheirownway。Foreithernotanyandeverypartofthebodyisincreased,orbodiesmaybeincreasedotherwisethanbytheadditionofbody,ortheremaybetwobodiesinthesameplaceinwhichcasetheyareclaimingtosolveaquitegeneraldifficulty,butarenotprovingtheexistenceofvoid,orthewholebodymustbevoid,ifitisincreasedineverypartandisincreasedbymeansofvoid。Thesameargumentappliestotheashes。
  Itisevident,then,thatitiseasytorefutetheargumentsbywhichtheyprovetheexistenceofthevoid。
  8
  Letusexplainagainthatthereisnovoidexistingseparately,assomemaintain。Ifeachofthesimplebodieshasanaturallocomotion,e。g。fireupwardandearthdownwardandtowardsthemiddleoftheuniverse,itisclearthatitcannotbethevoidthatistheconditionoflocomotion。What,then,willthevoidbetheconditionof?Itisthoughttobetheconditionofmovementinrespectofplace,anditisnottheconditionofthis。
  Again,ifvoidisasortofplacedeprivedofbody,whenthereisavoidwherewillabodyplacedinitmoveto?Itcertainlycannotmoveintothewholeofthevoid。Thesameargumentappliesasagainstthosewhothinkthatplaceissomethingseparate,intowhichthingsarecarried;viz。howwillwhatisplacedinitmove,orrest?Muchthesameargumentwillapplytothevoidastothe'up'and'down'inplace,asisnaturalenoughsincethosewhomaintaintheexistenceofthevoidmakeitaplace。
  Andinwhatwaywillthingsbepresenteitherinplace-orinthevoid?Fortheexpectedresultdoesnottakeplacewhenabodyisplacedasawholeinaplaceconceivedofasseparateandpermanent;
  forapartofit,unlessitbeplacedapart,willnotbeinaplacebutinthewhole。Further,ifseparateplacedoesnotexist,neitherwillvoid。
  Ifpeoplesaythatthevoidmustexist,asbeingnecessaryifthereistobemovement,whatratherturnsouttobethecase,ifonethematter,istheopposite,thatnotasinglethingcanbemovedifthereisavoid;foraswiththosewhoforalikereasonsaytheearthisatrest,so,too,inthevoidthingsmustbeatrest;
  forthereisnoplacetowhichthingscanmovemoreorlessthantoanother;sincethevoidinsofarasitisvoidadmitsnodifference。
  Thesecondreasonisthis:allmovementiseithercompulsoryoraccordingtonature,andifthereiscompulsorymovementtheremustalsobenaturalforcompulsorymovementiscontrarytonature,andmovementcontrarytonatureisposteriortothataccordingtonature,sothatifeachofthenaturalbodieshasnotanaturalmovement,noneoftheothermovementscanexist;buthowcantherebenaturalmovementifthereisnodifferencethroughoutthevoidortheinfinite?Forinsofarasitisinfinite,therewillbenoupordownormiddle,andinsofarasitisavoid,updiffersnowhitfromdown;forasthereisnodifferenceinwhatisnothing,thereisnoneinthevoidforthevoidseemstobeanon-existentandaprivationofbeing,butnaturallocomotionseemstobedifferentiated,sothatthethingsthatexistbynaturemustbedifferentiated。Either,then,nothinghasanaturallocomotion,orelsethereisnovoid。
  Further,inpointoffactthingsthatarethrownmovethoughthatwhichgavethemtheirimpulseisnottouchingthem,eitherbyreasonofmutualreplacement,assomemaintain,orbecausetheairthathasbeenpushedpushesthemwithamovementquickerthanthenaturallocomotionoftheprojectilewherewithitmovestoitsproperplace。
  Butinavoidnoneofthesethingscantakeplace,norcananythingbemovedsaveasthatwhichiscarriedismoved。
  Further,noonecouldsaywhyathingoncesetinmotionshouldstopanywhere;forwhyshoulditstophereratherthanhere?Sothatathingwilleitherbeatrestormustbemovedadinfinitum,unlesssomethingmorepowerfulgetinitsway。
  Further,thingsarenowthoughttomoveintothevoidbecauseityields;butinavoidthisqualityispresentequallyeverywhere,sothatthingsshouldmoveinalldirections。
  Further,thetruthofwhatweassertisplainfromthefollowingconsiderations。Weseethesameweightorbodymovingfasterthananotherfortworeasons,eitherbecausethereisadifferenceinwhatitmovesthrough,asbetweenwater,air,andearth,orbecause,otherthingsbeingequal,themovingbodydiffersfromtheotherowingtoexcessofweightoroflightness。
  Nowthemediumcausesadifferencebecauseitimpedesthemovingthing,mostofallifitismovingintheoppositedirection,butinasecondarydegreeevenifitisatrest;andespeciallyamediumthatisnoteasilydivided,i。e。amediumthatissomewhatdense。A,then,willmovethroughBintimeG,andthroughD,whichisthinner,intimeEifthelengthofBisegualtoD,inproportiontothedensityofthehinderingbody。ForletBbewaterandDair;
  thenbysomuchasairisthinnerandmoreincorporealthanwater,A
  willmovethroughDfasterthanthroughB。Letthespeedhavethesameratiotothespeed,then,thatairhastowater。Thenifairistwiceasthin,thebodywilltraverseBintwicethetimethatitdoesD,andthetimeGwillbetwicethetimeE。Andalways,bysomuchasthemediumismoreincorporealandlessresistantandmoreeasilydivided,thefasterwillbethemovement。
  Nowthereisnoratioinwhichthevoidisexceededbybody,asthereisnoratioof0toanumber。Forif4exceeds3by1,and2
  bymorethan1,and1bystillmorethanitexceeds2,stillthereisnoratiobywhichitexceeds0;forthatwhichexceedsmustbedivisibleintotheexcessthatwhichisexceeded,sothatwillbewhatitexceeds0by0。Forthisreason,too,alinedoesnotexceedapointunlessitiscomposedofpoints!Similarlythevoidcanbearnoratiotothefull,andthereforeneithercanmovementthroughtheonetomovementthroughtheother,butifathingmovesthroughthethickestmediumsuchandsuchadistanceinsuchandsuchatime,itmovesthroughthevoidwithaspeedbeyondanyratio。ForletZbevoid,equalinmagnitudetoBandtoD。ThenifAistotraverseandmovethroughitinacertaintime,H,atimelessthanE,however,thevoidwillbearthisratiotothefull。ButinatimeequaltoH,A
  willtraversethepartOofA。AnditwillsurelyalsotraverseinthattimeanysubstanceZwhichexceedsairinthicknessintheratiowhichthetimeEbearstothetimeH。ForifthebodyZbeasmuchthinnerthanDasEexceedsH,A,ifitmovesthroughZ,willtraverseitinatimeinversetothespeedofthemovement,i。e。inatimeequaltoH。If,then,thereisnobodyinZ,AwilltraverseZstillmorequickly。ButwesupposedthatitstraverseofZwhenZ
  wasvoidoccupiedthetimeH。SothatitwilltraverseZinanequaltimewhetherZbefullorvoid。Butthisisimpossible。Itisplain,then,thatifthereisatimeinwhichitwillmovethroughanypartofthevoid,thisimpossibleresultwillfollow:itwillbefoundtotraverseacertaindistance,whetherthisbefullorvoid,inanequaltime;fortherewillbesomebodywhichisinthesameratiototheotherbodyasthetimeistothetime。
  Tosumthematterup,thecauseofthisresultisobvious,viz。thatbetweenanytwomovementsthereisaratiofortheyoccupytime,andthereisaratiobetweenanytwotimes,solongasbotharefinite,butthereisnoratioofvoidtofull。
  Thesearetheconsequencesthatresultfromadifferenceinthemedia;thefollowingdependuponanexcessofonemovingbodyoveranother。Weseethatbodieswhichhaveagreaterimpulseeitherofweightoroflightness,iftheyarealikeinotherrespects,movefasteroveranequalspace,andintheratiowhichtheirmagnitudesbeartoeachother。Thereforetheywillalsomovethroughthevoidwiththisratioofspeed。Butthatisimpossible;forwhyshouldonemovefaster?Inmovingthroughplenaitmustbeso;forthegreaterdividesthemfasterbyitsforce。Foramovingthingcleavesthemediumeitherbyitsshape,orbytheimpulsewhichthebodythatiscarriedalongorisprojectedpossesses。Thereforeallwillpossessequalvelocity。Butthisisimpossible。
  Itisevidentfromwhathasbeensaid,then,that,ifthereisavoid,aresultfollowswhichistheveryoppositeofthereasonforwhichthosewhobelieveinavoidsetitup。Theythinkthatifmovementinrespectofplaceistoexist,thevoidcannotexist,separatedallbyitself;butthisisthesameastosaythatplaceisaseparatecavity;andthishasalreadybeenstatedtobeimpossible。
  Butevenifweconsideritonitsownmeritstheso-calledvacuumwillbefoundtobereallyvacuous。Foras,ifoneputsacubeinwater,anamountofwaterequaltothecubewillbedisplaced;sotooinair;buttheeffectisimperceptibletosense。Andindeedalwaysinthecaseofanybodythatcanbedisplaced,must,ifitisnotcompressed,bedisplacedinthedirectioninwhichitisitsnaturetobedisplaced-alwayseitherdown,ifitslocomotionisdownwardsasinthecaseofearth,orup,ifitisfire,orinbothdirections-whateverbethenatureoftheinsertedbody。Nowinthevoidthisisimpossible;foritisnotbody;thevoidmusthavepenetratedthecubetoadistanceequaltothatwhichthisportionofvoidformerlyoccupiedinthevoid,justasifthewaterorairhadnotbeendisplacedbythewoodencube,buthadpenetratedrightthroughit。
  Butthecubealsohasamagnitudeequaltothatoccupiedbythevoid;amagnitudewhich,ifitisalsohotorcold,orheavyorlight,isnonethelessdifferentinessencefromallitsattributes,evenifitisnotseparablefromthem;Imeanthevolumeofthewoodencube。
  Sothatevenifitwereseparatedfromeverythingelseandwereneitherheavynorlight,itwilloccupyanequalamountofvoid,andfillthesameplace,asthepartofplaceorofthevoidequaltoitself。Howthenwillthebodyofthecubedifferfromthevoidorplacethatisequaltoit?Andiftherecanbetwosuchthings,whycannottherebeanynumbercoinciding?
  This,then,isoneabsurdandimpossibleimplicationofthetheory。Itisalsoevidentthatthecubewillhavethissamevolumeevenifitisdisplaced,whichisanattributepossessedbyallotherbodiesalso。Thereforeifthisdiffersinnorespectfromitsplace,whyneedweassumeaplaceforbodiesoverandabovethevolumeofeach,iftheirvolumebeconceivedofasfreefromattributes?Itcontributesnothingtothesituationifthereisanequalintervalattachedtoitaswell。[Furtheritoughttobeclearbythestudyofmovingthingswhatsortofthingvoidis。Butinfactitisfoundnowhereintheworld。Forairissomething,thoughitdoesnotseemtobeso-nor,forthatmatter,wouldwater,iffishesweremadeofiron;forthediscriminationofthetangibleisbytouch。]
  Itisclear,then,fromtheseconsiderationsthatthereisnoseparatevoid。
  9
  Therearesomewhothinkthattheexistenceofrarityanddensityshowsthatthereisavoid。Ifrarityanddensitydonotexist,theysay,neithercanthingscontractandbecompressed。Butifthiswerenottotakeplace,eithertherewouldbenomovementatall,ortheuniversewouldbulge,asXuthussaid,orairandwatermustalwayschangeintoequalamountse。g。ifairhasbeenmadeoutofacupfulofwater,atthesametimeoutofanequalamountofairacupfulofwatermusthavebeenmade,orvoidmustnecessarilyexist;forcompressionandexpansioncannottakeplaceotherwise。
  Now,iftheymeanbytherarethatwhichhasmanyvoidsexistingseparately,itisplainthatifvoidcannotexistseparateanymorethanaplacecanexistwithanextensionalltoitself,neithercantherareexistinthissense。Butiftheymeanthatthereisvoid,notseparatelyexistent,butstillpresentintherare,thisislessimpossible,yet,first,thevoidturnsoutnottobeaconditionofallmovement,butonlyofmovementupwardsfortherareislight,whichisthereasonwhytheysayfireisrare;second,thevoidturnsouttobeaconditionofmovementnotasthatinwhichittakesplace,butinthatthevoidcarriesthingsupasskinsbybeingcarriedupthemselvescarryupwhatiscontinuouswiththem。Yethowcanvoidhavealocalmovementoraplace?Forthusthatintowhichvoidmovesistillthenvoidofavoid。
  Again,howwilltheyexplain,inthecaseofwhatisheavy,itsmovementdownwards?Anditisplainthatiftherarerandmorevoidathingisthequickeritwillmoveupwards,ifitwerecompletelyvoiditwouldmovewithamaximumspeed!Butperhapseventhisisimpossible,thatitshouldmoveatall;thesamereasonwhichshowedthatinthevoidallthingsareincapableofmovingshowsthatthevoidcannotmove,viz。thefactthatthespeedsareincomparable。
  Sincewedenythatavoidexists,butfortheresttheproblemhasbeentrulystated,thateithertherewillbenomovement,ifthereisnottobecondensationandrarefaction,ortheuniversewillbulge,oratransformationofwaterintoairwillalwaysbebalancedbyanequaltransformationofairintowaterforitisclearthattheairproducedfromwaterisbulkierthanthewater:itisnecessarytherefore,ifcompressiondoesnotexist,eitherthatthenextportionwillbepushedoutwardsandmaketheoutermostpartbulge,orthatsomewhereelsetheremustbeanequalamountofwaterproducedoutofair,sothattheentirebulkofthewholemaybeequal,orthatnothingmoves。Forwhenanythingisdisplacedthiswillalwayshappen,unlessitcomesroundinacircle;butlocomotionisnotalwayscircular,butsometimesinastraightline。
  Thesethenarethereasonsforwhichtheymightsaythatthereisavoid;ourstatementisbasedontheassumptionthatthereisasinglematterforcontraries,hotandcoldandtheothernaturalcontrarieties,andthatwhatexistsactuallyisproducedfromapotentialexistent,andthatmatterisnotseparablefromthecontrariesbutitsbeingisdifferent,andthatasinglemattermayserveforcolourandheatandcold。
  Thesamematteralsoservesforbothalargeandasmallbody。
  Thisisevident;forwhenairisproducedfromwater,thesamematterhasbecomesomethingdifferent,notbyacquiringanadditiontoit,buthasbecomeactuallywhatitwaspotentially,and,again,waterisproducedfromairinthesameway,thechangebeingsometimesfromsmallnesstogreatness,andsometimesfromgreatnesstosmallness。Similarly,therefore,ifairwhichislargeinextentcomestohaveasmallervolume,orbecomesgreaterfrombeingsmaller,itisthematterwhichispotentiallyboththatcomestobeeachofthetwo。
  Forasthesamematterbecomeshotfrombeingcold,andcoldfrombeinghot,becauseitwaspotentiallyboth,sotoofromhotitcanbecomemorehot,thoughnothinginthematterhasbecomehotthatwasnothotwhenthethingwaslesshot;justas,ifthearcorcurveofagreatercirclebecomesthatofasmaller,whetheritremainsthesameorbecomesadifferentcurve,convexityhasnotcometoexistinanythingthatwasnotconvexbutstraightfordifferencesofdegreedonotdependonanintermissionofthequality;norcanwegetanyportionofaflame,inwhichbothheatandwhitenessarenotpresent。Sotoo,then,istheearlierheatrelatedtothelater。Sothatthegreatnessandsmallness,also,ofthesensiblevolumeareextended,notbythematter'sacquiringanythingnew,butbecausethematterispotentiallymatterforbothstates;sothatthesamethingisdenseandrare,andthetwoqualitieshaveonematter。
  Thedenseisheavy,andtherareislight。[Again,asthearcofacirclewhencontractedintoasmallerspacedoesnotacquireanewpartwhichisconvex,butwhatwastherehasbeencontracted;andasanypartoffirethatonetakeswillbehot;so,too,itisallaquestionofcontractionandexpansionofthesamematter。]Therearetwotypesineachcase,bothinthedenseandintherare;forboththeheavyandthehardarethoughttobedense,andcontrariwiseboththelightandthesoftarerare;andweightandhardnessfailtocoincideinthecaseofleadandiron。
  Fromwhathasbeensaiditisevident,then,thatvoiddoesnotexisteitherseparateeitherabsolutelyseparateorasaseparateelementintherareorpotentially,unlessoneiswillingtocalltheconditionofmovementvoid,whateveritmaybe。Atthatratethematteroftheheavyandthelight,quamatterofthem,wouldbethevoid;forthedenseandtherareareproductiveoflocomotioninvirtueofthiscontrariety,andinvirtueoftheirhardnessandsoftnessproductiveofpassivityandimpassivity,i。e。notoflocomotionbutratherofqualitativechange。
  Somuch,then,forthediscussionofthevoid,andofthesenseinwhichitexistsandthesenseinwhichitdoesnotexist。
  10
  NextfordiscussionafterthesubjectsmentionedisTime。Thebestplanwillbetobeginbyworkingoutthedifficultiesconnectedwithit,makinguseofthecurrentarguments。First,doesitbelongtotheclassofthingsthatexistortothatofthingsthatdonotexist?
  Thensecondly,whatisitsnature?Tostart,then:thefollowingconsiderationswouldmakeonesuspectthatiteitherdoesnotexistatallorbarely,andinanobscureway。Onepartofithasbeenandisnot,whiletheotherisgoingtobeandisnotyet。Yettime-bothinfinitetimeandanytimeyouliketotake-ismadeupofthese。Onewouldnaturallysupposethatwhatismadeupofthingswhichdonotexistcouldhavenoshareinreality。
  Further,ifadivisiblethingistoexist,itisnecessarythat,whenitexists,allorsomeofitspartsmustexist。Butoftimesomepartshavebeen,whileothershavetobe,andnopartofitisthoughitisdivisible。Forwhatis'now'isnotapart:apartisameasureofthewhole,whichmustbemadeupofparts。Time,ontheotherhand,isnotheldtobemadeupof'nows'。
  Again,the'now'whichseemstoboundthepastandthefuture-doesitalwaysremainoneandthesameorisitalwaysotherandother?
  Itishardtosay。
  1Ifitisalwaysdifferentanddifferent,andifnoneofthepartsintimewhichareotherandotheraresimultaneousunlesstheonecontainsandtheotheriscontained,astheshortertimeisbythelonger,andifthe'now'whichisnot,butformerlywas,musthaveceased-to-beatsometime,the'nows'toocannotbesimultaneouswithoneanother,buttheprior'now'mustalwayshaveceased-to-be。
  Buttheprior'now'cannothaveceased-to-beinitselfsinceitthenexisted;yetitcannothaveceased-to-beinanother'now'。Forwemaylayitdownthatone'now'cannotbenexttoanother,anymorethanpointtopoint。Ifthenitdidnotcease-to-beinthenext'now'butinanother,itwouldexistsimultaneouslywiththeinnumerable'nows'betweenthetwo-whichisimpossible。
  Yes,but2neitherisitpossibleforthe'now'toremainalwaysthesame。Nodeterminatedivisiblethinghasasingletermination,whetheritiscontinuouslyextendedinoneorinmorethanonedimension:butthe'now'isatermination,anditispossibletocutoffadeterminatetime。Further,ifcoincidenceintimei。e。beingneitherpriornorposteriormeanstobe'inoneandthesame“now“',then,ifbothwhatisbeforeandwhatisafterareinthissame'now',thingswhichhappenedtenthousandyearsagowouldbesimultaneouswithwhathashappenedto-day,andnothingwouldbebeforeorafteranythingelse。
  Thismayserveasastatementofthedifficultiesabouttheattributesoftime。
  Astowhattimeisorwhatisitsnature,thetraditionalaccountsgiveusaslittlelightasthepreliminaryproblemswhichwehaveworkedthrough。
  Someassertthatitis1themovementofthewhole,othersthatitis2thesphereitself。
  1Yetpart,too,oftherevolutionisatime,butitcertainlyisnotarevolution:forwhatistakenispartofarevolution,notarevolution。Besides,ifthereweremoreheavensthanone,themovementofanyofthemequallywouldbetime,sothattherewouldbemanytimesatthesametime。
  2Thosewhosaidthattimeisthesphereofthewholethoughtso,nodoubt,onthegroundthatallthingsareintimeandallthingsareinthesphereofthewhole。Theviewistoonaiveforittobeworthwhiletoconsidertheimpossibilitiesimpliedinit。
  Butastimeismostusuallysupposedtobe3motionandakindofchange,wemustconsiderthisview。
  Nowathechangeormovementofeachthingisonlyinthethingwhichchangesorwherethethingitselfwhichmovesorchangesmaychancetobe。Buttimeispresentequallyeverywhereandwithallthings。
  Again,bchangeisalwaysfasterorslower,whereastimeisnot:
  for'fast'and'slow'aredefinedbytime-'fast'iswhatmovesmuchinashorttime,'slow'whatmoveslittleinalongtime;buttimeisnotdefinedbytime,bybeingeitheracertainamountoracertainkindofit。
  Clearlythenitisnotmovement。Weneednotdistinguishatpresentbetween'movement'and'change'。
  11
  Butneitherdoestimeexistwithoutchange;forwhenthestateofourownmindsdoesnotchangeatall,orwehavenotnoticeditschanging,wedonotrealizethattimehaselapsed,anymorethanthosewhoarefabledtosleepamongtheheroesinSardiniadowhentheyareawakened;fortheyconnecttheearlier'now'withthelaterandmakethemone,cuttingouttheintervalbecauseoftheirfailuretonoticeit。So,justas,ifthe'now'werenotdifferentbutoneandthesame,therewouldnothavebeentime,sotoowhenitsdifferenceescapesournoticetheintervaldoesnotseemtobetime。If,then,thenon-realizationoftheexistenceoftimehappenstouswhenwedonotdistinguishanychange,butthesoulseemstostayinoneindivisiblestate,andwhenweperceiveanddistinguishwesaytimehaselapsed,evidentlytimeisnotindependentofmovementandchange。
  Itisevident,then,thattimeisneithermovementnorindependentofmovement。
  Wemusttakethisasourstarting-pointandtrytodiscover-sincewewishtoknowwhattimeis-whatexactlyithastodowithmovement。
  Nowweperceivemovementandtimetogether:forevenwhenitisdarkandwearenotbeingaffectedthroughthebody,ifanymovementtakesplaceinthemindweatoncesupposethatsometimealsohaselapsed;andnotonlythatbutalso,whensometimeisthoughttohavepassed,somemovementalsoalongwithitseemstohavetakenplace。
  Hencetimeiseithermovementorsomethingthatbelongstomovement。
  Sincethenitisnotmovement,itmustbetheother。
  Butwhatismovedismovedfromsomethingtosomething,andallmagnitudeiscontinuous。Thereforethemovementgoeswiththemagnitude。Becausethemagnitudeiscontinuous,themovementtoomustbecontinuous,andifthemovement,thenthetime;forthetimethathaspassedisalwaysthoughttobeinproportiontothemovement。
  Thedistinctionof'before'and'after'holdsprimarily,then,inplace;andthereinvirtueofrelativeposition。Sincethen'before'
  and'after'holdinmagnitude,theymustholdalsoinmovement,thesecorrespondingtothose。Butalsointimethedistinctionof'before'and'after'musthold,fortimeandmovementalwayscorrespondwitheachother。The'before'and'after'inmotionisidenticalinsubstratumwithmotionyetdiffersfromitindefinition,andisnotidenticalwithmotion。
  Butweapprehendtimeonlywhenwehavemarkedmotion,markingitby'before'and'after';anditisonlywhenwehaveperceived'before'
  and'after'inmotionthatwesaythattimehaselapsed。NowwemarkthembyjudgingthatAandBaredifferent,andthatsomethirdthingisintermediatetothem。Whenwethinkoftheextremesasdifferentfromthemiddleandthemindpronouncesthatthe'nows'
  aretwo,onebeforeandoneafter,itisthenthatwesaythatthereistime,andthisthatwesayistime。Forwhatisboundedbythe'now'isthoughttobetime-wemayassumethis。
  When,therefore,weperceivethe'now'one,andneitherasbeforeandafterinamotionnorasanidentitybutinrelationtoa'before'
  andan'after',notimeisthoughttohaveelapsed,becausetherehasbeennomotioneither。Ontheotherhand,whenwedoperceivea'before'andan'after',thenwesaythatthereistime。Fortimeisjustthis-numberofmotioninrespectof'before'and'after'。
  Hencetimeisnotmovement,butonlymovementinsofarasitadmitsofenumeration。Aproofofthis:wediscriminatethemoreorthelessbynumber,butmoreorlessmovementbytime。Timethenisakindofnumber。Number,wemustnote,isusedintwosenses-bothofwhatiscountedorthecountableandalsoofthatwithwhichwecount。Timeobviouslyiswhatiscounted,notthatwithwhichwecount:therearedifferentkindsofthing。Justasmotionisaperpetualsuccession,soalsoistime。Buteverysimultaneoustimeisself-identical;forthe'now'asasubjectisanidentity,butitacceptsdifferentattributes。The'now'measurestime,insofarastimeinvolvesthe'beforeandafter'。
  The'now'inonesenseisthesame,inanotheritisnotthesame。
  Insofarasitisinsuccession,itisdifferentwhichisjustwhatitsbeingwassupposedtomean,butitssubstratumisanidentity:formotion,aswassaid,goeswithmagnitude,andtime,aswemaintain,withmotion。Similarly,then,therecorrespondstothepointthebodywhichiscarriedalong,andbywhichweareawareofthemotionandofthe'beforeandafter'involvedinit。Thisisanidenticalsubstratumwhetherapointorastoneorsomethingelseofthekind,butithasdifferentattributesasthesophistsassumethatCoriscus'beingintheLyceumisadifferentthingfromCoriscus'
  beinginthemarket-place。Andthebodywhichiscarriedalongisdifferent,insofarasitisatonetimehereandatanotherthere。
  Butthe'now'correspondstothebodythatiscarriedalong,astimecorrespondstothemotion。Foritisbymeansofthebodythatiscarriedalongthatwebecomeawareofthe'beforeandafter'themotion,andifweregardtheseascountablewegetthe'now'。Henceinthesealsothe'now'assubstratumremainsthesameforitiswhatisbeforeandafterinmovement,butwhatispredicatedofitisdifferent;foritisinsofarasthe'beforeandafter'isnumerablethatwegetthe'now'。Thisiswhatismostknowable:for,similarly,motionisknownbecauseofthatwhichismoved,locomotionbecauseofthatwhichiscarried。whatiscarriedisarealthing,themovementisnot。Thuswhatiscalled'now'inonesenseisalwaysthesame;inanotheritisnotthesame:forthisistruealsoofwhatiscarried。
  Clearly,too,iftherewerenotime,therewouldbeno'now',andviceversa。justasthemovingbodyanditslocomotioninvolveeachothermutually,sotoodothenumberofthemovingbodyandthenumberofitslocomotion。Forthenumberofthelocomotionistime,whilethe'now'correspondstothemovingbody,andisliketheunitofnumber。
  Time,then,alsoisbothmadecontinuousbythe'now'anddividedatit。Forheretoothereisacorrespondencewiththelocomotionandthemovingbody。Forthemotionorlocomotionismadeonebythethingwhichismoved,becauseitisone-notbecauseitisoneinitsownnaturefortheremightbepausesinthemovementofsuchathing-butbecauseitisoneindefinition:forthisdeterminesthemovementas'before'and'after'。Here,toothereisacorrespondencewiththepoint;forthepointalsobothconnectsandterminatesthelength-itisthebeginningofoneandtheendofanother。Butwhenyoutakeitinthisway,usingtheonepointastwo,apauseisnecessary,ifthesamepointistobethebeginningandtheend。The'now'ontheotherhand,sincethebodycarriedismoving,isalwaysdifferent。
  Hencetimeisnotnumberinthesenseinwhichthereis'number'
  ofthesamepointbecauseitisbeginningandend,butratherastheextremitiesofalineformanumber,andnotasthepartsofthelinedoso,bothforthereasongivenforwecanusethemiddlepointastwo,sothatonthatanalogytimemightstandstill,andfurtherbecauseobviouslythe'now'isnopartoftimenorthesectionanypartofthemovement,anymorethanthepointsarepartsoftheline-foritistwolinesthatarepartsofoneline。
  Insofarthenasthe'now'isaboundary,itisnottime,butanattributeofit;insofarasitnumbers,itisnumber;forboundariesbelongonlytothatwhichtheybound,butnumbere。g。tenisthenumberofthesehorses,andbelongsalsoelsewhere。
  Itisclear,then,thattimeis'numberofmovementinrespectofthebeforeandafter',andiscontinuoussinceitisanattributeofwhatiscontinuous。
  12
  Thesmallestnumber,inthestrictsenseoftheword'number',istwo。Butofnumberasconcrete,sometimesthereisaminimum,sometimesnot:e。g。ofa'line',thesmallestinrespectofmultiplicityistwoor,ifyoulike,one,butinrespectofsizethereisnominimum;foreverylineisdividedadinfinitum。Henceitissowithtime。Inrespectofnumbertheminimumisoneortwo;inpointofextentthereisnominimum。
  Itisclear,too,thattimeisnotdescribedasfastorslow,butasmanyorfewandaslongorshort。Forascontinuousitislongorshortandasanumbermanyorfew,butitisnotfastorslow-anymorethananynumberwithwhichwenumberisfastorslow。
  Further,thereisthesametimeeverywhereatonce,butnotthesametimebeforeandafter,forwhilethepresentchangeisone,thechangewhichhashappenedandthatwhichwillhappenaredifferent。Timeisnotnumberwithwhichwecount,butthenumberofthingswhicharecounted,andthisaccordingasitoccursbeforeorafterisalwaysdifferent,forthe'nows'aredifferent。Andthenumberofahundredhorsesandahundredmenisthesame,butthethingsnumberedaredifferent-thehorsesfromthemen。Further,asamovementcanbeoneandthesameagainandagain,sotoocantime,e。g。ayearoraspringoranautumn。
  Notonlydowemeasurethemovementbythetime,butalsothetimebythemovement,becausetheydefineeachother。Thetimemarksthemovement,sinceitisitsnumber,andthemovementthetime。Wedescribethetimeasmuchorlittle,measuringitbythemovement,justasweknowthenumberbywhatisnumbered,e。g。thenumberofthehorsesbyonehorseastheunit。Forweknowhowmanyhorsestherearebytheuseofthenumber;andagainbyusingtheonehorseasunitweknowthenumberofthehorsesitself。Soitiswiththetimeandthemovement;forwemeasurethemovementbythetimeandviceversa。Itisnaturalthatthisshouldhappen;forthemovementgoeswiththedistanceandthetimewiththemovement,becausetheyarequantaandcontinuousanddivisible。Themovementhastheseattributesbecausethedistanceisofthisnature,andthetimehasthembecauseofthemovement。Andwemeasureboththedistancebythemovementandthemovementbythedistance;forwesaythattheroadislong,ifthejourneyislong,andthatthisislong,iftheroadislong-thetime,too,ifthemovement,andthemovement,ifthetime。
  Timeisameasureofmotionandofbeingmoved,anditmeasuresthemotionbydeterminingamotionwhichwillmeasureexactlythewholemotion,asthecubitdoesthelengthbydetermininganamountwhichwillmeasureoutthewhole。Further'tobeintime'meansformovement,thatbothitanditsessencearemeasuredbytimeforsimultaneouslyitmeasuresboththemovementanditsessence,andthisiswhatbeingintimemeansforit,thatitsessenceshouldbemeasured。
  Clearlythen'tobeintime'hasthesamemeaningforotherthingsalso,namely,thattheirbeingshouldbemeasuredbytime。'Tobeintime'isoneoftwothings:1toexistwhentimeexists,2aswesayofsomethingsthattheyare'innumber'。Thelattermeanseitherwhatisapartormodeofnumber-ingeneral,somethingwhichbelongstonumber-orthatthingshaveanumber。
  Now,sincetimeisnumber,the'now'andthe'before'andthelikeareintime,justas'unit'and'odd'and'even'areinnumber,i。e。
  inthesensethattheonesetbelongstonumber,theothertotime。
  Butthingsareintimeastheyareinnumber。Ifthisisso,theyarecontainedbytimeasthingsinplacearecontainedbyplace。
  Plainly,too,tobeintimedoesnotmeantoco-existwithtime,anymorethantobeinmotionorinplacemeanstoco-existwithmotionorplace。Forif'tobeinsomething'istomeanthis,thenallthingswillbeinanything,andtheheavenwillbeinagrain;forwhenthegrainis,thenalsoistheheaven。Butthisisamerelyincidentalconjunction,whereastheotherisnecessarilyinvolved:thatwhichisintimenecessarilyinvolvesthatthereistimewhenitis,andthatwhichisinmotionthatthereismotionwhenitis。
  Sincewhatis'intime'issointhesamesenseaswhatisinnumberisso,atimegreaterthaneverythingintimecanbefound。Soitisnecessarythatallthethingsintimeshouldbecontainedbytime,justlikeotherthingsalsowhichare'inanything',e。g。thethings'inplace'byplace。
  Athing,then,willbeaffectedbytime,justasweareaccustomedtosaythattimewastesthingsaway,andthatallthingsgrowoldthroughtime,andthatthereisoblivionowingtothelapseoftime,butwedonotsaythesameofgettingtoknoworofbecomingyoungorfair。Fortimeisbyitsnaturethecauseratherofdecay,sinceitisthenumberofchange,andchangeremoveswhatis。
  Hence,plainly,thingswhicharealwaysarenot,assuch,intime,fortheyarenotcontainedtime,noristheirbeingmeasuredbytime。Aproofofthisisthatnoneofthemisaffectedbytime,whichindicatesthattheyarenotintime。
  Sincetimeisthemeasureofmotion,itwillbethemeasureofresttoo-indirectly。Forallrestisintime。Foritdoesnotfollowthatwhatisintimeismoved,thoughwhatisinmotionisnecessarilymoved。Fortimeisnotmotion,but'numberofmotion':andwhatisatrest,also,canbeinthenumberofmotion。Noteverythingthatisnotinmotioncanbesaidtobe'atrest'-butonlythatwhichcanbemoved,thoughitactuallyisnotmoved,aswassaidabove。
  'Tobeinnumber'meansthatthereisanumberofthething,andthatitsbeingismeasuredbythenumberinwhichitis。Henceifathingis'intime'itwillbemeasuredbytime。Buttimewillmeasurewhatismovedandwhatisatrest,theonequamoved,theotherquaatrest;foritwillmeasuretheirmotionandrestrespectively。
  Hencewhatismovedwillnotbemeasurablebythetimesimplyinsofarasithasquantity,butinsofarasitsmotionhasquantity。
  Thusnoneofthethingswhichareneithermovednoratrestareintime:for'tobeintime'is'tobemeasuredbytime',whiletimeisthemeasureofmotionandrest。
  Plainly,then,neitherwilleverythingthatdoesnotexistbeintime,i。e。thosenon-existentthingsthatcannotexist,asthediagonalcannotbecommensuratewiththeside。
  Generally,iftimeisdirectlythemeasureofmotionandindirectlyofotherthings,itisclearthatathingwhoseexistenceismeasuredbyitwillhaveitsexistenceinrestormotion。Thosethingsthereforewhicharesubjecttoperishingandbecoming-generally,thosewhichatonetimeexist,atanotherdonot-arenecessarilyintime:forthereisagreatertimewhichwillextendbothbeyondtheirexistenceandbeyondthetimewhichmeasurestheirexistence。Ofthingswhichdonotexistbutarecontainedbytimesomewere,e。g。Homeroncewas,somewillbe,e。g。afutureevent;thisdependsonthedirectioninwhichtimecontainsthem;ifonboth,theyhavebothmodesofexistence。Astosuchthingsasitdoesnotcontaininanyway,theyneitherwerenorarenorwillbe。Thesearethosenonexistentswhoseoppositesalwaysare,astheincommensurabilityofthediagonalalwaysis-andthiswillnotbeintime。Norwillthecommensurability,therefore;hencethiseternallyisnot,becauseitiscontrarytowhateternallyis。Athingwhosecontraryisnoteternalcanbeandnotbe,anditisofsuchthingsthatthereiscomingtobeandpassingaway。
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  The'now'isthelinkoftime,ashasbeensaidforitconnectspastandfuturetime,anditisalimitoftimeforitisthebeginningoftheoneandtheendoftheother。Butthisisnotobviousasitiswiththepoint,whichisfixed。Itdividespotentially,andinsofarasitisdividingthe'now'isalwaysdifferent,butinsofarasitconnectsitisalwaysthesame,asitiswithmathematicallines。Fortheintellectitisnotalwaysoneandthesamepoint,sinceitisotherandotherwhenonedividestheline;
  butinsofarasitisone,itisthesameineveryrespect。
  Sothe'now'alsoisinonewayapotentialdividingoftime,inanothertheterminationofbothparts,andtheirunity。Andthedividingandtheunitingarethesamethingandinthesamereference,butinessencetheyarenotthesame。
  Soonekindof'now'isdescribedinthisway:anotheriswhenthetimeisnearthiskindof'now'。'Hewillcomenow'becausehewillcometo-day;'hehascomenow'becausehecameto-day。ButthethingsintheIliadhavenothappened'now',noristheflood'now'-notthatthetimefromnowtothemisnotcontinuous,butbecausetheyarenotnear。
  'Atsometime'meansatimedeterminedinrelationtothefirstofthetwotypesof'now',e。g。'atsometime'Troywastaken,and'atsometime'therewillbeaflood;foritmustbedeterminedwithreferencetothe'now'。Therewillthusbeadeterminatetimefromthis'now'tothat,andtherewassuchinreferencetothepastevent。
  Butiftherebenotimewhichisnot'sometime',everytimewillbedetermined。
  Willtimethenfail?Surelynot,ifmotionalwaysexists。Istimethenalwaysdifferentordoesthesametimerecur?Clearlytimeis,inthesamewayasmotionis。Forifoneandthesamemotionsometimesrecurs,itwillbeoneandthesametime,andifnot,not。
  Sincethe'now'isanendandabeginningoftime,notofthesametimehowever,buttheendofthatwhichispastandthebeginningofthatwhichistocome,itfollowsthat,asthecirclehasitsconvexityanditsconcavity,inasense,inthesamething,sotimeisalwaysatabeginningandatanend。Andforthisreasonitseemstobealwaysdifferent;forthe'now'isnotthebeginningandtheendofthesamething;ifitwere,itwouldbeatthesametimeandinthesamerespecttwoopposites。Andtimewillnotfail;foritisalwaysatabeginning。
  'Presently'or'just'referstothepartoffuturetimewhichisneartheindivisiblepresent'now''Whendoyouwalk?'Presently',becausethetimeinwhichheisgoingtodosoisnear,andtothepartofpasttimewhichisnotfarfromthe'now''Whendoyouwalk?'
  'Ihavejustbeenwalking'。ButtosaythatTroyhasjustbeentaken-wedonotsaythat,becauseitistoofarfromthe'now'。
  'Lately',too,referstothepartofpasttimewhichisnearthepresent'now'。'Whendidyougo?''Lately',ifthetimeisneartheexistingnow。'Longago'referstothedistantpast。
  'Suddenly'referstowhathasdepartedfromitsformerconditioninatimeimperceptiblebecauseofitssmallness;butitisthenatureofallchangetoalterthingsfromtheirformercondition。Intimeallthingscomeintobeingandpassaway;forwhichreasonsomecalleditthewisestofallthings,butthePythagoreanParoncalleditthemoststupid,becauseinitwealsoforget;andhiswasthetruerview。
  Itisclearthenthatitmustbeinitself,aswesaidbefore,theconditionofdestructionratherthanofcomingintobeingforchange,initself,makesthingsdepartfromtheirformercondition,andonlyincidentallyofcomingintobeing,andofbeing。Asufficientevidenceofthisisthatnothingcomesintobeingwithoutitselfmovingsomehowandacting,butathingcanbedestroyedevenifitdoesnotmoveatall。Andthisiswhat,asarule,wechieflymeanbyathing'sbeingdestroyedbytime。Still,timedoesnotworkeventhischange;eventhissortofchangetakesplaceincidentallyintime。
  Wehavestated,then,thattimeexistsandwhatitis,andinhowmanysenseswespeakofthe'now',andwhat'atsometime','lately','presently'or'just','longago',and'suddenly'mean。