1
　　WHENtheobjectsofaninquiry，inanydepartment，haveprinciples，conditions，orelements，itisthroughacquaintancewiththesethatknowledge，thatistosayscientificknowledge，isattained。Forwedonotthinkthatweknowathinguntilweareacquaintedwithitsprimaryconditionsorfirstprinciples，andhavecarriedouranalysisasfarasitssimplestelements。PlainlythereforeinthescienceofNature，asinotherbranchesofstudy，ourfirsttaskwillbetotrytodeterminewhatrelatestoitsprinciples。
　　Thenaturalwayofdoingthisistostartfromthethingswhicharemoreknowableandobvioustousandproceedtowardsthosewhichareclearerandmoreknowablebynature；forthesamethingsarenot'knowablerelativelytous'and'knowable'withoutqualification。Sointhepresentinquirywemustfollowthismethodandadvancefromwhatismoreobscurebynature，butclearertous，towardswhatismoreclearandmoreknowablebynature。
　　Nowwhatistousplainandobviousatfirstisratherconfusedmasses，theelementsandprinciplesofwhichbecomeknowntouslaterbyanalysis。Thuswemustadvancefromgeneralitiestoparticulars；foritisawholethatisbestknowntosense-perception，andageneralityisakindofwhole，comprehendingmanythingswithinit，likeparts。Muchthesamethinghappensintherelationofthenametotheformula。Aname，e。g。'round'，meansvaguelyasortofwhole:itsdefinitionanalysesthisintoitsparticularsenses。
　　Similarlyachildbeginsbycallingallmen'father'，andallwomen'mother'，butlaterondistinguisheseachofthem。
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　　Theprinciplesinquestionmustbeeitheraoneorbmorethanone。Ifaone，itmustbeeitherimotionless，asParmenidesandMelissusassert，oriiinmotion，asthephysicistshold，somedeclaringairtobethefirstprinciple，otherswater。Ifbmorethanone，theneitheriafiniteoriianinfiniteplurality。Ififinitebutmorethanone，theneithertwoorthreeorfourorsomeothernumber。Ifiiinfinite，theneitherasDemocritusbelievedoneinkind，butdifferinginshapeorform；ordifferentinkindandevencontrary。
　　Asimilarinquiryismadebythosewhoinquireintothenumberofexistents:fortheyinquirewhethertheultimateconstituentsofexistingthingsareoneormany，andifmany，whetherafiniteoraninfiniteplurality。Sotheytooareinquiringwhethertheprincipleorelementisoneormany。
　　NowtoinvestigatewhetherBeingisoneandmotionlessisnotacontributiontothescienceofNature。Forjustasthegeometerhasnothingmoretosaytoonewhodeniestheprinciplesofhisscience-thisbeingaquestionforadifferentscienceorfororcommontoall-soamaninvestigatingprinciplescannotarguewithonewhodeniestheirexistence。ForifBeingisjustone，andoneinthewaymentioned，thereisaprinciplenolonger，sinceaprinciplemustbetheprincipleofsomethingorthings。
　　ToinquirethereforewhetherBeingisoneinthissensewouldbelikearguingagainstanyotherpositionmaintainedforthesakeofargumentsuchastheHeracliteanthesis，orsuchathesisasthatBeingisonemanorlikerefutingamerelycontentiousargument-adescriptionwhichappliestotheargumentsbothofMelissusandofParmenides:theirpremissesarefalseandtheirconclusionsdonotfollow。OrrathertheargumentofMelissusisgrossandpalpableandoffersnodifficultyatall:acceptoneridiculouspropositionandtherestfollows-asimpleenoughproceeding。
　　Wephysicists，ontheotherhand，musttakeforgrantedthatthethingsthatexistbynatureare，eitherallorsomeofthem，inmotionwhichisindeedmadeplainbyinduction。Moreover，nomanofscienceisboundtosolveeverykindofdifficultythatmayberaised，butonlyasmanyasaredrawnfalselyfromtheprinciplesofthescience:itisnotourbusinesstorefutethosethatdonotariseinthisway:justasitisthedutyofthegeometertorefutethesquaringofthecirclebymeansofsegments，butitisnothisdutytorefuteAntiphon'sproof。Atthesametimetheholdersofthetheoryofwhichwearespeakingdoincidentallyraisephysicalquestions，thoughNatureisnottheirsubject:soitwillperhapsbeaswelltospendafewwordsonthem，especiallyastheinquiryisnotwithoutscientificinterest。
　　Themostpertinentquestionwithwhichtobeginwillbethis:Inwhatsenseisitassertedthatallthingsareone?For'is'isusedinmanysenses。Dotheymeanthatallthings'are'substanceorquantitiesorqualities?And，further，areallthingsonesubstance-oneman，onehorse，oronesoul-orqualityandthatoneandthesame-whiteorhotorsomethingofthekind?Theseareallverydifferentdoctrinesandallimpossibletomaintain。
　　Forifbothsubstanceandquantityandqualityare，then，whethertheseexistindependentlyofeachotherornot，Beingwillbemany。
　　Ifontheotherhanditisassertedthatallthingsarequalityorquantity，then，whethersubstanceexistsornot，anabsurdityresults，iftheimpossiblecanproperlybecalledabsurd。Fornoneoftheotherscanexistindependently:substancealoneisindependent:foreverythingispredicatedofsubstanceassubject。NowMelissussaysthatBeingisinfinite。Itisthenaquantity。Fortheinfiniteisinthecategoryofquantity，whereassubstanceorqualityoraffectioncannotbeinfiniteexceptthroughaconcomitantattribute，thatis，ifatthesametimetheyarealsoquantities。Fortodefinetheinfiniteyoumustusequantityinyourformula，butnotsubstanceorquality。IfthenBeingisbothsubstanceandquantity，itistwo，notone:ifonlysubstance，itisnotinfiniteandhasnomagnitude；
　　fortohavethatitwillhavetobeaquantity。
　　Again，'one'itself，nolessthan'being'，isusedinmanysenses，sowemustconsiderinwhatsensethewordisusedwhenitissaidthattheAllisone。
　　Nowwesaythatathecontinuousisoneorthatbtheindivisibleisone，orcthingsaresaidtobe'one'，whentheiressenceisoneandthesame，as'liquor'and'drink'。
　　IfatheirOneisoneinthesenseofcontinuous，itismany，forthecontinuousisdivisibleadinfinitum。
　　Thereis，indeed，adifficultyaboutpartandwhole，perhapsnotrelevanttothepresentargument，yetdeservingconsiderationonitsownaccount-namely，whetherthepartandthewholeareoneormorethanone，andhowtheycanbeoneormany，and，iftheyaremorethanone，inwhatsensetheyaremorethanone。Similarlywiththepartsofwholeswhicharenotcontinuous。Further，ifeachofthetwopartsisindivisiblyonewiththewhole，thedifficultyarisesthattheywillbeindivisiblyonewitheachotheralso。
　　Buttoproceed:IfbtheirOneisoneasindivisible，nothingwillhavequantityorquality，andsotheonewillnotbeinfinite，asMelissussays-nor，indeed，limited，asParmenidessays，forthoughthelimitisindivisible，thelimitedisnot。
　　Butifcallthingsareoneinthesenseofhavingthesamedefinition，like'raiment'and'dress'，thenitturnsoutthattheyaremaintainingtheHeracliteandoctrine，foritwillbethesamething'tobegood'and'tobebad'，and'tobegood'and'tobenotgood'，andsothesamethingwillbe'good'and'notgood'，andmanandhorse；infact，theirviewwillbe，notthatallthingsareone，butthattheyarenothing；andthat'tobeofsuch-and-suchaquality'
　　isthesameas'tobeofsuch-and-suchasize'。
　　Eventhemorerecentoftheancientthinkerswereinapotherlestthesamethingshouldturnoutintheirhandsbothoneandmany。Sosome，likeLycophron，wereledtoomit'is'，otherstochangethemodeofexpressionandsay'themanhasbeenwhitened'insteadof'iswhite'，and'walks'insteadof'iswalking'，forfearthatiftheyaddedtheword'is'theyshouldbemakingtheonetobemany-asif'one'and'being'werealwaysusedinoneandthesamesense。What'is'maybemanyeitherindefinitionforexample'tobewhite'isonething，'tobemusical'another，yetthesamethingbeboth，sotheoneismanyorbydivision，asthewholeanditsparts。Onthispoint，indeed，theywerealreadygettingintodifficultiesandadmittedthattheonewasmany-asiftherewasanydifficultyaboutthesamethingbeingbothoneandmany，providedthatthesearenotopposites；for'one'maymeaneither'potentiallyone'or'actuallyone'。
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　　If，then，weapproachthethesisinthiswayitseemsimpossibleforallthingstobeone。Further，theargumentstheyusetoprovetheirpositionarenotdifficulttoexpose。Forbothofthemreasoncontentiously-ImeanbothMelissusandParmenides。[Theirpremissesarefalseandtheirconclusionsdonotfollow。OrrathertheargumentofMelissusisgrossandpalpableandoffersnodifficultyatall:admitoneridiculouspropositionandtherestfollows-asimpleenoughproceeding。]ThefallacyofMelissusisobvious。Forhesupposesthattheassumption'whathascomeintobeingalwayshasabeginning'justifiestheassumption'whathasnotcomeintobeinghasnobeginning'。Thenthisalsoisabsurd，thatineverycasethereshouldbeabeginningofthething-notofthetimeandnotonlyinthecaseofcomingtobeinthefullsensebutalsointhecaseofcomingtohaveaquality-asifchangenevertookplacesuddenly。Again，doesitfollowthatBeing，ifone，ismotionless?Whyshoulditnotmove，thewholeofitwithinitself，aspartsofitdowhichareunities，e。g。thiswater?Again，whyisqualitativechangeimpossible?But，further，Beingcannotbeoneinform，thoughitmaybeinwhatitismadeof。Evensomeofthephysicistsholdittobeoneinthelatterway，thoughnotintheformer。Manobviouslydiffersfromhorseinform，andcontrariesfromeachother。
　　ThesamekindofargumentholdsgoodagainstParmenidesalso，besidesanythatmayapplyspeciallytohisview:theanswertohimbeingthat'thisisnottrue'and'thatdoesnotfollow'。Hisassumptionthatoneisusedinasinglesenseonlyisfalse，becauseitisusedinseveral。Hisconclusiondoesnotfollow，becauseifwetakeonlywhitethings，andif'white'hasasinglemeaning，nonethelesswhatiswhitewillbemanyandnotone。Forwhatiswhitewillnotbeoneeitherinthesensethatitiscontinuousorinthesensethatitmustbedefinedinonlyoneway。'Whiteness'willbedifferentfrom'whathaswhiteness'。Nordoesthismeanthatthereisanythingthatcanexistseparately，overandabovewhatiswhite。
　　For'whiteness'and'thatwhichiswhite'differindefinition，notinthesensethattheyarethingswhichcanexistapartfromeachother。ButParmenideshadnotcomeinsightofthisdistinction。
　　Itisnecessaryforhim，then，toassumenotonlythat'being'hasthesamemeaning，ofwhateveritispredicated，butfurtherthatitmeans1whatjustisand2whatisjustone。
　　Itmustbeso，for1anattributeispredicatedofsomesubject，sothatthesubjecttowhich'being'isattributedwillnotbe，asitissomethingdifferentfrom'being'。Something，therefore，whichisnotwillbe。Hence'substance'willnotbeapredicateofanythingelse。Forthesubjectcannotbeabeing，unless'being'meansseveralthings，insuchawaythateachissomething。Butexhypothesi'being'meansonlyonething。
　　If，then，'substance'isnotattributedtoanything，butotherthingsareattributedtoit，howdoes'substance'meanwhatisratherthanwhatisnot?Forsupposethat'substance'isalso'white'。
　　Sincethedefinitionofthelatterisdifferentforbeingcannotevenbeattributedtowhite，asnothingiswhichisnot'substance'，itfollowsthat'white'isnot-being——andthatnotinthesenseofaparticularnot-being，butinthesensethatitisnotatall。Hence'substance'isnot；foritistruetosaythatitiswhite，whichwefoundtomeannot-being。Iftoavoidthiswesaythateven'white'
　　meanssubstance，itfollowsthat'being'hasmorethanonemeaning。
　　Inparticular，then，Beingwillnothavemagnitude，ifitissubstance。Foreachofthetwopartsmustheinadifferentsense。
　　2Substanceisplainlydivisibleintoothersubstances，ifweconsiderthemerenatureofadefinition。Forinstance，if'man'isasubstance，'animal'and'biped'mustalsobesubstances。Forifnotsubstances，theymustbeattributes-andifattributes，attributeseitherofamanorofbsomeothersubject。Butneitherispossible。
　　aAnattributeiseitherthatwhichmayormaynotbelongtothesubjectorthatinwhosedefinitionthesubjectofwhichitisanattributeisinvolved。Thus'sitting'isanexampleofaseparableattribute，while'snubness'containsthedefinitionof'nose'，towhichweattributesnubness。Further，thedefinitionofthewholeisnotcontainedinthedefinitionsofthecontentsorelementsofthedefinitoryformula；thatof'man'forinstancein'biped'，orthatof'whiteman'in'white'。Ifthenthisisso，andif'biped'issupposedtobeanattributeof'man'，itmustbeeitherseparable，sothat'man'mightpossiblynotbe'biped'，orthedefinitionof'man'mustcomeintothedefinitionof'biped'-whichisimpossible，astheconverseisthecase。
　　bIf，ontheotherhand，wesupposethat'biped'and'animal'
　　areattributesnotofmanbutofsomethingelse，andarenoteachofthemasubstance，then'man'toowillbeanattributeofsomethingelse。Butwemustassumethatsubstanceisnottheattributeofanything，thatthesubjectofwhichboth'biped'and'animal'andeachseparatelyarepredicatedisthesubjectalsoofthecomplex'bipedanimal'。
　　ArewethentosaythattheAlliscomposedofindivisiblesubstances?Somethinkersdid，inpointoffact，givewaytobotharguments。Totheargumentthatallthingsareoneifbeingmeansonething，theyconcededthatnot-beingis；tothatfrombisection，theyyieldedbypositingatomicmagnitudes。Butobviouslyitisnottruethatifbeingmeansonething，andcannotatthesametimemeanthecontradictoryofthis，therewillbenothingwhichisnot，forevenifwhatisnotcannotbewithoutqualification，thereisnoreasonwhyitshouldnotbeaparticularnot-being。Tosaythatallthingswillbeone，ifthereisnothingbesidesBeingitself，isabsurd。Forwhounderstands'beingitself'tobeanythingbutaparticularsubstance?Butifthisisso，thereisnothingtopreventtherebeingmanybeings，ashasbeensaid。
　　Itis，then，clearlyimpossibleforBeingtobeoneinthissense。
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　　Thephysicistsontheotherhandhavetwomodesofexplanation。
　　Thefirstsetmaketheunderlyingbodyoneeitheroneofthethreeorsomethingelsewhichisdenserthanfireandrarerthanairthengenerateeverythingelsefromthis，andobtainmultiplicitybycondensationandrarefaction。Nowthesearecontraries，whichmaybegeneralizedinto'excessanddefect'。ComparePlato's'GreatandSmall'-exceptthathemakethesehismatter，theonehisform，whiletheotherstreattheonewhichunderliesasmatterandthecontrariesasdifferentiae，i。e。forms。
　　Thesecondsetassertthatthecontrarietiesarecontainedintheoneandemergefromitbysegregation，forexampleAnaximanderandalsoallthosewhoassertthat'whatis'isoneandmany，likeEmpedoclesandAnaxagoras；fortheytooproduceotherthingsfromtheirmixturebysegregation。Thesediffer，however，fromeachotherinthattheformerimaginesacycleofsuchchanges，thelatterasingleseries。Anaxagorasagainmadebothhis'homceomerous'
　　substancesandhiscontrariesinfiniteinmultitude，whereasEmpedoclespositsonlytheso-calledelements。
　　ThetheoryofAnaxagorasthattheprinciplesareinfiniteinmultitudewasprobablyduetohisacceptanceofthecommonopinionofthephysiciststhatnothingcomesintobeingfromnot-being。Forthisisthereasonwhytheyusethephrase'allthingsweretogether'andthecomingintobeingofsuchandsuchakindofthingisreducedtochangeofquality，whilesomespokeofcombinationandseparation。Moreover，thefactthatthecontrariesproceedfromeachotherledthemtotheconclusion。Theone，theyreasoned，musthavealreadyexistedintheother；forsinceeverythingthatcomesintobeingmustariseeitherfromwhatisorfromwhatisnot，anditisimpossibleforittoarisefromwhatisnotonthispointallthephysicistsagree，theythoughtthatthetruthofthealternativenecessarilyfollowed，namelythatthingscomeintobeingoutofexistentthings，i。e。outofthingsalreadypresent，butimperceptibletooursensesbecauseofthesmallnessoftheirbulk。Sotheyassertthateverythinghasbeenmixedinevery。thing，becausetheysaweverythingarisingoutofeverything。Butthings，astheysay，appeardifferentfromoneanotherandreceivedifferentnamesaccordingtothenatureoftheparticleswhicharenumericallypredominantamongtheinnumerableconstituentsofthemixture。Fornothing，theysay，ispurelyandentirelywhiteorblackorsweet，boneorflesh，butthenatureofathingisheldtobethatofwhichitcontainsthemost。
　　Now1theinfinitequainfiniteisunknowable，sothatwhatisinfiniteinmultitudeorsizeisunknowableinquantity，andwhatisinfiniteinvarietyofkindisunknowableinquality。Buttheprinciplesinquestionareinfinitebothinmultitudeandinkind。
　　Thereforeitisimpossibletoknowthingswhicharecomposedofthem；foritiswhenweknowthenatureandquantityofitscomponentsthatwesupposeweknowacomplex。
　　Further2ifthepartsofawholemaybeofanysizeinthedirectioneitherofgreatnessorofsmallnessby'parts'Imeancomponentsintowhichawholecanbedividedandwhichareactuallypresentinit，itisnecessarythatthewholethingitselfmaybeofanysize。Clearly，therefore，sinceitisimpossibleforananimalorplanttobeindefinitelybigorsmall，neithercanitspartsbesuch，orthewholewillbethesame。Butflesh，bone，andthelikearethepartsofanimals，andthefruitsarethepartsofplants。
　　Henceitisobviousthatneitherflesh，bone，noranysuchthingcanbeofindefinitesizeinthedirectioneitherofthegreateroroftheless。
　　Again3accordingtothetheoryallsuchthingsarealreadypresentinoneanotheranddonotcomeintobeingbutareconstituentswhichareseparatedout，andathingreceivesitsdesignationfromitschiefconstituent。Further，anythingmaycomeoutofanything-waterbysegregationfromfleshandfleshfromwater。Hence，sinceeveryfinitebodyisexhaustedbytherepeatedabstractionofafinitebody，itseemsobviouslytofollowthateverythingcannotsubsistineverythingelse。Forletfleshbeextractedfromwaterandagainmorefleshbeproducedfromtheremainderbyrepeatingtheprocessofseparation:
　　then，eventhoughthequantityseparatedoutwillcontinuallydecrease，stillitwillnotfallbelowacertainmagnitude。If，therefore，theprocesscomestoanend，everythingwillnotbeineverythingelsefortherewillbenofleshintheremainingwater；
　　ifontheotherhanditdoesnot，andfurtherextractionisalwayspossible，therewillbeaninfinitemultitudeoffiniteequalparticlesinafinitequantity-whichisimpossible。Anotherproofmaybeadded:Sinceeverybodymustdiminishinsizewhensomethingistakenfromit，andfleshisquantitativelydefiniteinrespectbothofgreatnessandsmallness，itisclearthatfromtheminimumquantityoffleshnobodycanbeseparatedout；forthefleshleftwouldbelessthantheminimumofflesh。
　　Lastly4ineachofhisinfinitebodiestherewouldbealreadypresentinfinitefleshandbloodandbrain-havingadistinctexistence，however，fromoneanother，andnolessrealthantheinfinitebodies，andeachinfinite:whichiscontrarytoreason。
　　Thestatementthatcompleteseparationneverwilltakeplaceiscorrectenough，thoughAnaxagorasisnotfullyawareofwhatitmeans。
　　Foraffectionsareindeedinseparable。Ifthencoloursandstateshadenteredintothemixture，andifseparationtookplace，therewouldbea'white'ora'healthy'whichwasnothingbutwhiteorhealthy，i。e。wasnotthepredicateofasubject。Sohis'Mind'isanabsurdpersonaimingattheimpossible，ifheissupposedtowishtoseparatethem，anditisimpossibletodoso，bothinrespectofquantityandofquality-ofquantity，becausethereisnominimummagnitude，andofquality，becauseaffectionsareinseparable。
　　NorisAnaxagorasrightaboutthecomingtobeofhomogeneousbodies。Itistruethereisasenseinwhichclayisdividedintopiecesofclay，butthereisanotherinwhichitisnot。Waterandairare，andaregenerated'from'eachother，butnotinthewayinwhichbrickscome'from'ahouseandagainahouse'from'bricks；
　　anditisbettertoassumeasmallerandfinitenumberofprinciples，asEmpedoclesdoes。
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　　Allthinkersthenagreeinmakingthecontrariesprinciples，boththosewhodescribetheAllasoneandunmovedforevenParmenidestreatshotandcoldasprinciplesunderthenamesoffireandearth
　　andthosetoowhousetherareandthedense。ThesameistrueofDemocritusalso，withhisplenumandvoid，bothofwhichexist，besays，theoneasbeing，theotherasnot-being。Againhespeaksofdifferencesinposition，shape，andorder，andthesearegeneraofwhichthespeciesarecontraries，namely，ofposition，aboveandbelow，beforeandbehind；ofshape，angularandangle-less，straightandround。
　　Itisplainthenthattheyallinonewayoranotheridentifythecontrarieswiththeprinciples。Andwithgoodreason。Forfirstprinciplesmustnotbederivedfromoneanothernorfromanythingelse，whileeverythinghastobederivedfromthem。Buttheseconditionsarefulfilledbytheprimarycontraries，whicharenotderivedfromanythingelsebecausetheyareprimary，norfromeachotherbecausetheyarecontraries。
　　Butwemustseehowthiscanbearrivedatasareasonedresult，aswellasinthewayjustindicated。
　　Ourfirstpresuppositionmustbethatinnaturenothingactson，orisactedonby，anyotherthingatrandom，normayanythingcomefromanythingelse，unlesswemeanthatitdoessoinvirtueofaconcomitantattribute。Forhowcould'white'comefrom'musical'，unless'musical'happenedtobeanattributeofthenot-whiteoroftheblack?No，'white'comesfrom'not-white'-andnotfromany'not-white'，butfromblackorsomeintermediatecolour。Similarly，'musical'comestobefrom'not-musical'，butnotfromanythingotherthanmusical，butfrom'unmusical'oranyintermediatestatetheremaybe。
　　Noragaindothingspassintothefirstchancething；'white'doesnotpassinto'musical'except，itmaybe，invirtueofaconcomitantattribute，butinto'not-white'-andnotintoanychancethingwhichisnotwhite，butintoblackoranintermediatecolour；'musical'
　　passesinto'not-musical'-andnotintoanychancethingotherthanmusical，butinto'unmusical'oranyintermediatestatetheremaybe。
　　Thesameholdsofotherthingsalso:eventhingswhicharenotsimplebutcomplexfollowthesameprinciple，buttheoppositestatehasnotreceivedaname，sowefailtonoticethefact。Whatisintunemustcomefromwhatisnotintune，andviceversa；thetunedpassesintountunedness-andnotintoanyuntunedness，butintothecorrespondingopposite。Itdoesnotmatterwhetherwetakeattunement，order，orcompositionforourillustration；theprincipleisobviouslythesameinall，andinfactappliesequallytotheproductionofahouse，astatue，oranyothercomplex。Ahousecomesfromcertainthingsinacertainstateofseparationinsteadofconjunction，astatueoranyotherthingthathasbeenshapedfromshapelessness-eachoftheseobjectsbeingpartlyorderandpartlycomposition。
　　Ifthenthisistrue，everythingthatcomestobeorpassesawayfrom，orpassesinto，itscontraryoranintermediatestate。Buttheintermediatesarederivedfromthecontraries-colours，forinstance，fromblackandwhite。Everything，therefore，thatcomestobebyanaturalprocessiseitheracontraryoraproductofcontraries。
　　Uptothispointwehavepracticallyhadmostoftheotherwritersonthesubjectwithus，asIhavesaidalready:forallofthemidentifytheirelements，andwhattheycalltheirprinciples，withthecontraries，givingnoreasonindeedforthetheory，butcontrainedasitwerebythetruthitself。Theydiffer，however，fromoneanotherinthatsomeassumecontrarieswhicharemoreprimary，otherscontrarieswhicharelessso:somethosemoreknowableintheorderofexplanation，othersthosemorefamiliartosense。Forsomemakehotandcold，oragainmoistanddry，theconditionsofbecoming；whileothersmakeoddandeven，oragainLoveandStrife；andthesedifferfromeachotherinthewaymentioned。
　　Hencetheirprinciplesareinonesensethesame，inanotherdifferent；differentcertainly，asindeedmostpeoplethink，butthesameinasmuchastheyareanalogous；forallaretakenfromthesametableofcolumns，someofthepairsbeingwider，othersnarrowerinextent。Inthiswaythentheirtheoriesareboththesameanddifferent，somebetter，someworse；some，asIhavesaid，takeastheircontrarieswhatismoreknowableintheorderofexplanation，otherswhatismorefamiliartosense。Theuniversalismoreknowableintheorderofexplanation，theparticularintheorderofsense:forexplanationhastodowiththeuniversal，sensewiththeparticular。'Thegreatandthesmall'，forexample，belongtotheformerclass，'thedenseandtherare'tothelatter。
　　Itisclearthenthatourprinciplesmustbecontraries。
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　　Thenextquestioniswhethertheprinciplesaretwoorthreeormoreinnumber。
　　Onetheycannotbe，fortherecannotbeonecontrary。Norcantheybeinnumerable，because，ifso，Beingwillnotbeknowable:andinanyonegenusthereisonlyonecontrariety，andsubstanceisonegenus:
　　alsoafinitenumberissufficient，andafinitenumber，suchastheprinciplesofEmpedocles，isbetterthananinfinitemultitude；forEmpedoclesprofessestoobtainfromhisprinciplesallthatAnaxagorasobtainsfromhisinnumerableprinciples。Lastly，somecontrariesaremoreprimarythanothers，andsomearisefromothers-forexamplesweetandbitter，whiteandblack-whereastheprinciplesmustalwaysremainprinciples。
　　Thiswillsufficetoshowthattheprinciplesareneitheronenorinnumerable。
　　Granted，then，thattheyarealimitednumber，itisplausibletosupposethemmorethantwo。Foritisdifficulttoseehoweitherdensityshouldbeofsuchanatureastoactinanywayonrarityorrarityondensity。Thesameistrueofanyotherpairofcontraries；
　　forLovedoesnotgatherStrifetogetherandmakethingsoutofit，nordoesStrifemakeanythingoutofLove，butbothactonathirdthingdifferentfromboth。Someindeedassumemorethanonesuchthingfromwhichtheyconstructtheworldofnature。
　　Otherobjectionstotheviewthatitisnotnecessarytoassumeathirdprincipleasasubstratummaybeadded。1Wedonotfindthatthecontrariesconstitutethesubstanceofanything。Butwhatisafirstprincipleoughtnottobethepredicateofanysubject。Ifitwere，therewouldbeaprincipleofthesupposedprinciple:forthesubjectisaprinciple，andpriorpresumablytowhatispredicatedofit。Again2weholdthatasubstanceisnotcontrarytoanothersubstance。Howthencansubstancebederivedfromwhatarenotsubstances?Orhowcannon-substancesbepriortosubstance?
　　Ifthenweacceptboththeformerargumentandthisone，wemust，topreserveboth，assumeathirdsomewhatasthesubstratumofthecontraries，suchasisspokenofbythosewhodescribetheAllasonenature-waterorfireorwhatisintermediatebetweenthem。Whatisintermediateseemspreferable；forfire，earth，air，andwaterarealreadyinvolvedwithpairsofcontraries。Thereis，therefore，muchtobesaidforthosewhomaketheunderlyingsubstancedifferentfromthesefour；oftherest，thenextbestchoiceisair，aspresentingsensibledifferencesinalessdegreethantheothers；
　　andafterair，water。All，however，agreeinthis，thattheydifferentiatetheirOnebymeansofthecontraries，suchasdensityandrarityandmoreandless，whichmayofcoursebegeneralized，ashasalreadybeensaidintoexcessanddefect。IndeedthisdoctrinetoothattheOneandexcessanddefectaretheprinciplesofthings
　　wouldappeartobeofoldstanding，thoughindifferentforms；fortheearlythinkersmadethetwotheactiveandtheonethepassiveprinciple，whereassomeofthemorerecentmaintainthereverse。
　　Tosupposethenthattheelementsarethreeinnumberwouldseem，fromtheseandsimilarconsiderations，aplausibleview，asIsaidbefore。Ontheotherhand，theviewthattheyaremorethanthreeinnumberwouldseemtobeuntenable。
　　Fortheonesubstratumissufficienttobeactedon；butifwehavefourcontraries，therewillbetwocontrarieties，andweshallhavetosupposeanintermediatenatureforeachpairseparately。If，ontheotherhand，thecontrarieties，beingtwo，cangeneratefromeachother，thesecondcontrarietywillbesuperfluous。Moreover，itisimpossiblethatthereshouldbemorethanoneprimarycontrariety。Forsubstanceisasinglegenusofbeing，sothattheprinciplescandifferonlyaspriorandposterior，notingenus；inasinglegenusthereisalwaysasinglecontrariety，alltheothercontrarietiesinitbeingheldtobereducibletoone。
　　Itisclearthenthatthenumberofelementsisneitheronenormorethantwoorthree；butwhethertwoorthreeis，asIsaid，aquestionofconsiderabledifficulty。
　　7
　　Wewillnowgiveourownaccount，approachingthequestionfirstwithreferencetobecominginitswidestsense:forweshallbefollowingthenaturalorderofinquiryifwespeakfirstofcommoncharacteristics，andtheninvestigatethecharacteristicsofspecialcases。
　　Wesaythatonethingcomestobefromanotherthing，andonesortofthingfromanothersortofthing，bothinthecaseofsimpleandofcomplexthings。Imeanthefollowing。Wecansay1'manbecomesmusical'，2whatis'not-musicalbecomesmusical'，or3，the'not-musicalmanbecomesamusicalman'。Nowwhatbecomesin1and2-'man'and'notmusical'-Icallsimple，andwhateachbecomes-'musical'-simplealso。Butwhen3wesaythe'not-musicalmanbecomesamusicalman'，bothwhatbecomesandwhatitbecomesarecomplex。
　　Asregardsoneofthesesimple'thingsthatbecome'wesaynotonly'thisbecomesso-and-so'，butalso'frombeingthis，comestobeso-and-so'，as'frombeingnot-musicalcomestobemusical'；asregardstheotherwedonotsaythisinallcases，aswedonotsay1'frombeingamanhecametobemusical'butonly'themanbecamemusical'。
　　Whena'simple'thingissaidtobecomesomething，inonecase1
　　itsurvivesthroughtheprocess，intheother2itdoesnot。Formanremainsamanandissuchevenwhenhebecomesmusical，whereaswhatisnotmusicalorisunmusicaldoesnotcontinuetoexist，eithersimplyorcombinedwiththesubject。
　　Thesedistinctionsdrawn，onecangatherfromsurveyingthevariouscasesofbecominginthewaywearedescribingthat，aswesay，theremustalwaysbeanunderlyingsomething，namelythatwhichbecomes，andthatthis，thoughalwaysonenumerically，informatleastisnotone。BythatImeanthatitcanbedescribedindifferentways。For'tobeman'isnotthesameas'tobeunmusical'。
　　Onepartsurvives，theotherdoesnot:whatisnotanoppositesurvivesfor'man'survives，but'not-musical'or'unmusical'doesnotsurvive，nordoesthecompoundofthetwo，namely'unmusicalman'。
　　Wespeakof'becomingthatfromthis'insteadof'thisbecomingthat'moreinthecaseofwhatdoesnotsurvivethechange-'becomingmusicalfromunmusical'，not'fromman'-butthereareexceptions，aswesometimesusethelatterformofexpressionevenofwhatsurvives；wespeakof'astatuecomingtobefrombronze'，notofthe'bronzebecomingastatue'。Thechange，however，fromanoppositewhichdoesnotsurviveisdescribedindifferentlyinbothways，'becomingthatfromthis'or'thisbecomingthat'。Wesayboththat'theunmusicalbecomesmusical'，andthat'fromunmusicalhebecomesmusical'。Andsobothformsareusedofthecomplex，'becomingamusicalmanfromanunmusicalman'，andunmusicalmanbecomingamusicalman'。
　　Buttherearedifferentsensesof'comingtobe'。Insomecaseswedonotusetheexpression'cometobe'，but'cometobeso-and-so'。
　　Onlysubstancesaresaidto'cometobe'intheunqualifiedsense。
　　Nowinallcasesotherthansubstanceitisplainthattheremustbesomesubject，namely，thatwhichbecomes。Forweknowthatwhenathingcomestobeofsuchaquantityorqualityorinsucharelation，time，orplace，asubjectisalwayspresupposed，sincesubstancealoneisnotpredicatedofanothersubject，buteverythingelseofsubstance。
　　Butthatsubstancestoo，andanythingelsethatcanbesaid'tobe'withoutqualification，cometobefromsomesubstratum，willappearonexamination。Forwefindineverycasesomethingthatunderliesfromwhichproceedsthatwhichcomestobe；forinstance，animalsandplantsfromseed。
　　Generallythingswhichcometobe，cometobeindifferentways:1
　　bychangeofshape，asastatue；2byaddition，asthingswhichgrow；3bytakingaway，astheHermesfromthestone；4byputtingtogether，asahouse；5byalteration，asthingswhich'turn'inrespectoftheirmaterialsubstance。
　　Itisplainthattheseareallcasesofcomingtobefromasubstratum。
　　Thus，clearly，fromwhathasbeensaid，whatevercomestobeisalwayscomplex。Thereis，ontheonehand，asomethingwhichcomesintoexistence，andagainbsomethingwhichbecomesthat-thelatterbintwosenses，eitherthesubjectortheopposite。Bythe'opposite'Imeanthe'unmusical'，bythe'subject''man'，andsimilarlyIcalltheabsenceofshapeorformororderthe'opposite'，andthebronzeorstoneorgoldthe'subject'。
　　Plainlythen，ifthereareconditionsandprincipleswhichconstitutenaturalobjectsandfromwhichtheyprimarilyareorhavecometobe-havecometobe，Imean，whateachissaidtobeinitsessentialnature，notwhateachisinrespectofaconcomitantattribute-plainly，Isay，everythingcomestobefrombothsubjectandform。For'musicalman'iscomposedinawayof'man'and'musical':
　　youcananalyseitintothedefinitionsofitselements。Itisclearthenthatwhatcomestobewillcometobefromtheseelements。
　　Nowthesubjectisonenumerically，thoughitistwoinform。Foritistheman，thegold-the'matter'generally-thatiscounted，foritismoreofthenatureofa'this'，andwhatcomestobedoesnotcomefromitinvirtueofaconcomitantattribute；theprivation，ontheotherhand，andthecontraryareincidentalintheprocess。Andthepositiveformisone-theorder，theacquiredartofmusic，oranysimilarpredicate。
　　Thereisasense，therefore，inwhichwemustdeclaretheprinciplestobetwo，andasenseinwhichtheyarethree；asenseinwhichthecontrariesaretheprinciples-sayforexamplethemusicalandtheunmusical，thehotandthecold，thetunedandtheuntuned-andasenseinwhichtheyarenot，sinceitisimpossibleforthecontrariestobeactedonbyeachother。Butthisdifficultyalsoissolvedbythefactthatthesubstratumisdifferentfromthecontraries，foritisitselfnotacontrary。Theprinciplesthereforeare，inaway，notmoreinnumberthanthecontraries，butasitweretwo，noryetpreciselytwo，sincethereisadifferenceofessentialnature，butthree。For'tobeman'isdifferentfrom'tobeunmusical'，and'tobeunformed'from'tobebronze'。
　　Wehavenowstatedthenumberoftheprinciplesofnaturalobjectswhicharesubjecttogeneration，andhowthenumberisreached:anditisclearthattheremustbeasubstratumforthecontraries，andthatthecontrariesmustbetwo。Yetinanotherwayofputtingitthisisnotnecessary，asoneofthecontrarieswillservetoeffectthechangebyitssuccessiveabsenceandpresence。
　　Theunderlyingnatureisanobjectofscientificknowledge，byananalogy。Forasthebronzeistothestatue，thewoodtothebed，orthematterandtheformlessbeforereceivingformtoanythingwhichhasform，soistheunderlyingnaturetosubstance，i。e。the'this'orexistent。
　　Thisthenisoneprinciplethoughnotoneorexistentinthesamesenseasthe'this'，andthedefinitionwasoneasweagreed；thenfurtherthereisitscontrary，theprivation。Inwhatsensethesearetwo，andinwhatsensemore，hasbeenstatedabove。Briefly，weexplainedfirstthatonlythecontrarieswereprinciples，andlaterthatasubstratumwasindispensable，andthattheprincipleswerethree；ourlaststatementhaselucidatedthedifferencebetweenthecontraries，themutualrelationoftheprinciples，andthenatureofthesubstratum。Whethertheformorthesubstratumistheessentialnatureofaphysicalobjectisnotyetclear。Butthattheprinciplesarethree，andinwhatsense，andthewayinwhicheachisaprinciple，isclear。
　　Somuchthenforthequestionofthenumberandthenatureoftheprinciples。
　　8
　　Wewillnowproceedtoshowthatthedifficultyoftheearlythinkers，aswellasourown，issolvedinthiswayalone。
　　Thefirstofthosewhostudiedscienceweremisledintheirsearchfortruthandthenatureofthingsbytheirinexperience，whichasitwerethrustthemintoanotherpath。Sotheysaythatnoneofthethingsthatareeithercomestobeorpassesoutofexistence，becausewhatcomestobemustdosoeitherfromwhatisorfromwhatisnot，bothofwhichareimpossible。Forwhatiscannotcometobebecauseitisalready，andfromwhatisnotnothingcouldhavecometobebecausesomethingmustbepresentasasubstratum。Sotootheyexaggeratedtheconsequenceofthis，andwentsofarastodenyeventheexistenceofapluralityofthings，maintainingthatonlyBeingitselfis。Suchthenwastheiropinion，andsuchthereasonforitsadoption。
　　Ourexplanationontheotherhandisthatthephrases'somethingcomestobefromwhatisorfromwhatisnot'，'whatisnotorwhatisdoessomethingorhassomethingdonetoitorbecomessomeparticularthing'，aretobetakeninthefirstwayofputtingourexplanationinthesamesenseas'adoctordoessomethingorhassomethingdonetohim'，'isorbecomessomethingfrombeingadoctor。'
　　Theseexpressionsmaybetakenintwosenses，andsotoo，clearly，may'frombeing'，and'beingactsorisactedon'。Adoctorbuildsahouse，notquadoctor，butquahousebuilder，andturnsgray，notquadoctor，butquadark-haired。Ontheotherhandhedoctorsorfailstodoctorquadoctor。Butweareusingwordsmostappropriatelywhenwesaythatadoctordoessomethingorundergoessomething，orbecomessomethingfrombeingadoctor，ifhedoes，undergoes，orbecomesquadoctor。Clearlythenalso'tocometobeso-and-sofromnot-being'
　　means'quanot-being'。
　　Itwasthroughfailuretomakethisdistinctionthatthosethinkersgavethematterup，andthroughthiserrorthattheywentsomuchfartherastrayastosupposethatnothingelsecomestobeorexistsapartfromBeingitself，thusdoingawaywithallbecoming。
　　Weourselvesareinagreementwiththeminholdingthatnothingcanbesaidwithoutqualificationtocomefromwhatisnot。Butneverthelesswemaintainthatathingmay'cometobefromwhatisnot'-thatis，inaqualifiedsense。Forathingcomestobefromtheprivation，whichinitsownnatureisnot-being，-thisnotsurvivingasaconstituentoftheresult。Yetthiscausessurprise，anditisthoughtimpossiblethatsomethingshouldcometobeinthewaydescribedfromwhatisnot。
　　Inthesamewaywemaintainthatnothingcomestobefrombeing，andthatbeingdoesnotcometobeexceptinaqualifiedsense。Inthatway，however，itdoes，justasanimalmightcometobefromanimal，andananimalofacertainkindfromananimalofacertainkind。
　　Thus，supposeadogtocometobefromahorse。Thedogwouldthen，itistrue，cometobefromanimalaswellasfromananimalofacertainkindbutnotasanimal，forthatisalreadythere。Butifanythingistobecomeananimal，notinaqualifiedsense，itwillnotbefromanimal:andifbeing，notfrombeing-norfromnot-beingeither，forithasbeenexplainedthatby'fromnotbeing'wemeanfromnot-beingquanot-being。
　　Notefurtherthatwedonotsubverttheprinciplethateverythingeitherisorisnot。
　　Thisthenisonewayofsolvingthedifficulty。Anotherconsistsinpointingoutthatthesamethingscanbeexplainedintermsofpotentialityandactuality。Butthishasbeendonewithgreaterprecisionelsewhere。So，aswesaid，thedifficultieswhichconstrainpeopletodenytheexistenceofsomeofthethingswementionedarenowsolved。Foritwasthisreasonwhichalsocausedsomeoftheearlierthinkerstoturnsofarasidefromtheroadwhichleadstocomingtobeandpassingawayandchangegenerally。
　　Iftheyhadcomeinsightofthisnature，alltheirignorancewouldhavebeendispelled。
　　9
　　Others，indeed，haveapprehendedthenatureinquestion，butnotadequately。
　　Inthefirstplacetheyallowthatathingmaycometobewithoutqualificationfromnotbeing，acceptingonthispointthestatementofParmenides。Secondly，theythinkthatifthesubstratumisonenumerically，itmusthavealsoonlyasinglepotentiality-whichisaverydifferentthing。
　　Nowwedistinguishmatterandprivation，andholdthatoneofthese，namelythematter，isnot-beingonlyinvirtueofanattributewhichithas，whiletheprivationinitsownnatureisnot-being；andthatthematterisnearly，inasenseis，substance，whiletheprivationinnosenseis。They，ontheotherhand，identifytheirGreatandSmallalikewithnotbeing，andthatwhethertheyaretakentogetherasoneorseparately。Theirtriadisthereforeofquiteadifferentkindfromours。Fortheygotsofarastoseethattheremustbesomeunderlyingnature，buttheymakeitone-forevenifonephilosophermakesadyadofit，whichhecallsGreatandSmall，theeffectisthesame，forheoverlookedtheothernature。Fortheonewhichpersistsisajointcause，withtheform，ofwhatcomestobe-amother，asitwere。Butthenegativepartofthecontrarietymayoftenseem，ifyouconcentrateyourattentiononitasanevilagent，nottoexistatall。
　　Foradmittingwiththemthatthereissomethingdivine，good，anddesirable，weholdthattherearetwootherprinciples，theonecontrarytoit，theothersuchasofitsownnaturetodesireandyearnforit。Buttheconsequenceoftheirviewisthatthecontrarydesiresitswtextinction。Yettheformcannotdesireitself，foritisnotdefective；norcanthecontrarydesireit，forcontrariesaremutuallydestructive。Thetruthisthatwhatdesirestheformismatter，asthefemaledesiresthemaleandtheuglythebeautiful-onlytheuglyorthefemalenotpersebutperaccidens。
　　Themattercomestobeandceasestobeinonesense，whileinanotheritdoesnot。Asthatwhichcontainstheprivation，itceasestobeinitsownnature，forwhatceasestobe-theprivation-iscontainedwithinit。Butaspotentialityitdoesnotceasetobeinitsownnature，butisnecessarilyoutsidethesphereofbecomingandceasingtobe。Forifitcametobe，somethingmusthaveexistedasaprimarysubstratumfromwhichitshouldcomeandwhichshouldpersistinit；butthisisitsownspecialnature，sothatitwillbebeforecomingtobe。Formydefinitionofmatterisjustthis-theprimarysubstratumofeachthing，fromwhichitcomestobewithoutqualification，andwhichpersistsintheresult。Andifitceasestobeitwillpassintothatatthelast，soitwillhaveceasedtobebeforeceasingtobe。
　　Theaccuratedeterminationofthefirstprincipleinrespectofform，whetheritisoneormanyandwhatitisorwhattheyare，istheprovinceoftheprimarytypeofscience；sothesequestionsmaystandovertillthen。Butofthenatural，i。e。perishable，formsweshallspeakintheexpositionswhichfollow。
　　Theabove，then，maybetakenassufficienttoestablishthatthereareprinciplesandwhattheyareandhowmanythereare。Nowletusmakeafreshstartandproceed。
　　BookII
　　1
　　Ofthingsthatexist，someexistbynature，somefromothercauses。
　　'Bynature'theanimalsandtheirpartsexist，andtheplantsandthesimplebodiesearth，fire，air，water-forwesaythattheseandthelikeexist'bynature'。
　　Allthethingsmentionedpresentafeatureinwhichtheydifferfromthingswhicharenotconstitutedbynature。Eachofthemhaswithinitselfaprincipleofmotionandofstationarinessinrespectofplace，orofgrowthanddecrease，orbywayofalteration。Ontheotherhand，abedandacoatandanythingelseofthatsort，quareceivingthesedesignationsi。e。insofarastheyareproductsofart-havenoinnateimpulsetochange。Butinsofarastheyhappentobecomposedofstoneorofearthorofamixtureofthetwo，theydohavesuchanimpulse，andjusttothatextentwhichseemstoindicatethatnatureisasourceorcauseofbeingmovedandofbeingatrestinthattowhichitbelongsprimarily，invirtueofitselfandnotinvirtueofaconcomitantattribute。
　　Isay'notinvirtueofaconcomitantattribute'，becauseforinstanceamanwhoisadoctormightcurehimself。Neverthelessitisnotinsofarasheisapatientthathepossessestheartofmedicine:itmerelyhashappenedthatthesamemanisdoctorandpatient-andthatiswhytheseattributesarenotalwaysfoundtogether。Soitiswithallotherartificialproducts。Noneofthemhasinitselfthesourceofitsownproduction。Butwhileinsomecasesforinstancehousesandtheotherproductsofmanuallabour
　　thatprincipleisinsomethingelseexternaltothething，inothersthosewhichmaycauseachangeinthemselvesinvirtueofaconcomitantattribute-itliesinthethingsthemselvesbutnotinvirtueofwhattheyare。
　　'Nature'theniswhathasbeenstated。Things'haveanature'whichhaveaprincipleofthiskind。Eachofthemisasubstance；foritisasubject，andnaturealwaysimpliesasubjectinwhichitinheres。
　　Theterm'accordingtonature'isappliedtoallthesethingsandalsototheattributeswhichbelongtotheminvirtueofwhattheyare，forinstancethepropertyoffiretobecarriedupwards-whichisnota'nature'nor'hasanature'butis'bynature'or'accordingtonature'。
　　Whatnatureis，then，andthemeaningoftheterms'bynature'and'accordingtonature'，hasbeenstated。Thatnatureexists，itwouldbeabsurdtotrytoprove；foritisobviousthattherearemanythingsofthiskind，andtoprovewhatisobviousbywhatisnotisthemarkofamanwhoisunabletodistinguishwhatisself-evidentfromwhatisnot。Thisstateofmindisclearlypossible。Amanblindfrombirthmightreasonaboutcolours。Presumablythereforesuchpersonsmustbetalkingaboutwordswithoutanythoughttocorrespond。
　　Someidentifythenatureorsubstanceofanaturalobjectwiththatimmediateconstituentofitwhichtakenbyitselfiswithoutarrangement，e。g。thewoodisthe'nature'ofthebed，andthebronzethe'nature'ofthestatue。
　　AsanindicationofthisAntiphonpointsoutthatifyouplantedabedandtherottingwoodacquiredthepowerofsendingupashoot，itwouldnotbeabedthatwouldcomeup，butwood-whichshowsthatthearrangementinaccordancewiththerulesoftheartismerelyanincidentalattribute，whereastherealnatureistheother，which，further，persistscontinuouslythroughtheprocessofmaking。
　　Butifthematerialofeachoftheseobjectshasitselfthesamerelationtosomethingelse，saybronzeorgoldtowater，bonesorwoodtoearthandsoon，thattheysaywouldbetheirnatureandessence。Consequentlysomeassertearth，othersfireorairorwaterorsomeorallofthese，tobethenatureofthethingsthatare。
　　Forwhateveranyoneofthemsupposedtohavethischaracter-whetheronethingormorethanonething-thisorthesehedeclaredtobethewholeofsubstance，allelsebeingitsaffections，states，ordispositions。Everysuchthingtheyheldtobeeternalforitcouldnotpassintoanythingelse，butotherthingstocomeintobeingandceasetobetimeswithoutnumber。
　　Thisthenisoneaccountof'nature'，namelythatitistheimmediatematerialsubstratumofthingswhichhaveinthemselvesaprincipleofmotionorchange。
　　Anotheraccountisthat'nature'istheshapeorformwhichisspecifiedinthedefinitionofthething。
　　Fortheword'nature'isappliedtowhatisaccordingtonatureandthenaturalinthesamewayas'art'isappliedtowhatisartisticoraworkofart。Weshouldnotsayinthelattercasethatthereisanythingartisticaboutathing，ifitisabedonlypotentially，notyethavingtheformofabed；norshouldwecallitaworkofart。Thesameistrueofnaturalcompounds。Whatispotentiallyfleshorbonehasnotyetitsown'nature'，anddoesnotexistuntilitreceivestheformspecifiedinthedefinition，whichwenameindefiningwhatfleshorboneis。Thusinthesecondsenseof'nature'itwouldbetheshapeorformnotseparableexceptinstatementofthingswhichhaveinthemselvesasourceofmotion。Thecombinationofthetwo，e。g。man，isnot'nature'but'bynature'or'natural'。
　　Theformindeedis'nature'ratherthanthematter；forathingismoreproperlysaidtobewhatitiswhenithasattainedtofulfilmentthanwhenitexistspotentially。Againmanisbornfromman，butnotbedfrombed。Thatiswhypeoplesaythatthefigureisnotthenatureofabed，butthewoodis-ifthebedsproutednotabedbutwoodwouldcomeup。Butevenifthefigureisart，thenonthesameprincipletheshapeofmanishisnature。Formanisbornfromman。
　　Wealsospeakofathing'snatureasbeingexhibitedintheprocessofgrowthbywhichitsnatureisattained。The'nature'inthissenseisnotlike'doctoring'，whichleadsnottotheartofdoctoringbuttohealth。Doctoringmuststartfromtheart，notleadtoit。Butitisnotinthiswaythatnatureintheonesenseisrelatedtonatureintheother。Whatgrowsquagrowinggrowsfromsomethingintosomething。Intowhatthendoesitgrow?Notintothatfromwhichitarosebutintothattowhichittends。Theshapethenisnature。
　　'Shape'and'nature'，itshouldbeadded，areintwosenses。Fortheprivationtooisinawayform。Butwhetherinunqualifiedcomingtobethereisprivation，i。e。acontrarytowhatcomestobe，wemustconsiderlater。
　　2
　　Wehavedistinguished，then，thedifferentwaysinwhichtheterm'nature'isused。
　　Thenextpointtoconsiderishowthemathematiciandiffersfromthephysicist。Obviouslyphysicalbodiescontainsurfacesandvolumes，linesandpoints，andthesearethesubject-matterofmathematics。
　　Further，isastronomydifferentfromphysicsoradepartmentofit?Itseemsabsurdthatthephysicistshouldbesupposedtoknowthenatureofsunormoon，butnottoknowanyoftheiressentialattributes，particularlyasthewritersonphysicsobviouslydodiscusstheirshapealsoandwhethertheearthandtheworldaresphericalornot。
　　Nowthemathematician，thoughhetootreatsofthesethings，neverthelessdoesnottreatofthemasthelimitsofaphysicalbody；nordoesheconsidertheattributesindicatedastheattributesofsuchbodies。Thatiswhyheseparatesthem；forinthoughttheyareseparablefrommotion，anditmakesnodifference，nordoesanyfalsityresult，iftheyareseparated。TheholdersofthetheoryofFormsdothesame，thoughtheyarenotawareofit；fortheyseparatetheobjectsofphysics，whicharelessseparablethanthoseofmathematics。Thisbecomesplainifonetriestostateineachofthetwocasesthedefinitionsofthethingsandoftheirattributes。
　　'Odd'and'even'，'straight'and'curved'，andlikewise'number'，'line'，and'figure'，donotinvolvemotion；notso'flesh'and'bone'
　　and'man'-thesearedefinedlike'snubnose'，notlike'curved'。
　　Similarevidenceissuppliedbythemorephysicalofthebranchesofmathematics，suchasoptics，harmonics，andastronomy。Theseareinawaytheconverseofgeometry。Whilegeometryinvestigatesphysicallinesbutnotquaphysical，opticsinvestigatesmathematicallines，butquaphysical，notquamathematical。
　　Since'nature'hastwosenses，theformandthematter，wemustinvestigateitsobjectsaswewouldtheessenceofsnubness。Thatis，suchthingsareneitherindependentofmatternorcanbedefinedintermsofmatteronly。Heretooindeedonemightraiseadifficulty。
　　Sincetherearetwonatures，withwhichisthephysicistconcerned?Orshouldheinvestigatethecombinationofthetwo?Butifthecombinationofthetwo，thenalsoeachseverally。Doesitbelongthentothesameortodifferentsciencestoknoweachseverally?
　　Ifwelookattheancients，physicswouldtobeconcernedwiththematter。ItwasonlyveryslightlythatEmpedoclesandDemocritustouchedontheformsandtheessence。
　　Butifontheotherhandartimitatesnature，anditisthepartofthesamedisciplinetoknowtheformandthematteruptoapointe。g。thedoctorhasaknowledgeofhealthandalsoofbileandphlegm，inwhichhealthisrealized，andthebuilderbothoftheformofthehouseandofthematter，namelythatitisbricksandbeams，andsoforth:ifthisisso，itwouldbethepartofphysicsalsotoknownatureinbothitssenses。
　　Again，'thatforthesakeofwhich'，ortheend，belongstothesamedepartmentofknowledgeasthemeans。Butthenatureistheendor'thatforthesakeofwhich'。Forifathingundergoesacontinuouschangeandthereisastagewhichislast，thisstageistheendor'thatforthesakeofwhich'。Thatiswhythepoetwascarriedawayintomakinganabsurdstatementwhenhesaid'hehastheendforthesakeofwhichhewasborn'。Fornoteverystagethatislastclaimstobeanend，butonlythatwhichisbest。
　　Fortheartsmaketheirmaterialsomesimply'make'it，othersmakeitserviceable，andweuseeverythingasifitwasthereforoursake。Wealsoareinasenseanend。'Thatforthesakeofwhich'hastwosenses:thedistinctionismadeinourworkOnPhilosophy。Thearts，therefore，whichgovernthematterandhaveknowledgearetwo，namelytheartwhichusestheproductandtheartwhichdirectstheproductionofit。Thatiswhytheusingartalsoisinasensedirective；butitdiffersinthatitknowstheform，whereastheartwhichisdirectiveasbeingconcernedwithproductionknowsthematter。Forthehelmsmanknowsandprescribeswhatsortofformahelmshouldhave，theotherfromwhatwooditshouldbemadeandbymeansofwhatoperations。Intheproductsofart，however，wemakethematerialwithaviewtothefunction，whereasintheproductsofnaturethematteristhereallalong。
　　Again，matterisarelativeterm:toeachformtherecorrespondsaspecialmatter。Howfarthenmustthephysicistknowtheformoressence?Uptoapoint，perhaps，asthedoctormustknowsineworthesmithbronzei。e。untilheunderstandsthepurposeofeach:
　　andthephysicistisconcernedonlywiththingswhoseformsareseparableindeed，butdonotexistapartfrommatter。Manisbegottenbymanandbythesunaswell。Themodeofexistenceandessenceoftheseparableitisthebusinessoftheprimarytypeofphilosophytodefine。
　　3
　　Nowthatwehaveestablishedthesedistinctions，wemustproceedtoconsidercauses，theircharacterandnumber。Knowledgeistheobjectofourinquiry，andmendonotthinktheyknowathingtilltheyhavegraspedthe'why'ofwhichistograspitsprimarycause。Soclearlywetoomustdothisasregardsbothcomingtobeandpassingawayandeverykindofphysicalchange，inorderthat，knowingtheirprinciples，wemaytrytorefertotheseprincipleseachofourproblems。
　　Inonesense，then，1thatoutofwhichathingcomestobeandwhichpersists，iscalled'cause'，e。g。thebronzeofthestatue，thesilverofthebowl，andthegeneraofwhichthebronzeandthesilverarespecies。
　　Inanothersense2theformorthearchetype，i。e。thestatementoftheessence，anditsgenera，arecalled'causes'e。g。oftheoctavetherelationof2:1，andgenerallynumber，andthepartsinthedefinition。
　　Again3theprimarysourceofthechangeorcomingtorest；e。g。
　　themanwhogaveadviceisacause，thefatheriscauseofthechild，andgenerallywhatmakesofwhatismadeandwhatcauseschangeofwhatischanged。
　　Again4inthesenseofendor'thatforthesakeofwhich'athingisdone，e。g。healthisthecauseofwalkingabout。'Whyishewalkingabout?'wesay。'Tobehealthy'，and，havingsaidthat，wethinkwehaveassignedthecause。Thesameistruealsoofalltheintermediatestepswhicharebroughtaboutthroughtheactionofsomethingelseasmeanstowardstheend，e。g。reductionofflesh，purging，drugs，orsurgicalinstrumentsaremeanstowardshealth。
　　Allthesethingsare'forthesakeof'theend，thoughtheydifferfromoneanotherinthatsomeareactivities，othersinstruments。
　　Thisthenperhapsexhauststhenumberofwaysinwhichtheterm'cause'isused。
　　Asthewordhasseveralsenses，itfollowsthatthereareseveralcausesofthesamethingnotmerelyinvirtueofaconcomitantattribute，e。g。boththeartofthesculptorandthebronzearecausesofthestatue。Thesearecausesofthestatuequastatue，notinvirtueofanythingelsethatitmaybe-onlynotinthesameway，theonebeingthematerialcause，theotherthecausewhencethemotioncomes。Somethingscauseeachotherreciprocally，e。g。hardworkcausesfitnessandviceversa，butagainnotinthesameway，buttheoneasend，theotherastheoriginofchange。Furtherthesamethingisthecauseofcontraryresults。Forthatwhichbyitspresencebringsaboutoneresultissometimesblamedforbringingaboutthecontrarybyitsabsence。Thusweascribethewreckofashiptotheabsenceofthepilotwhosepresencewasthecauseofitssafety。
　　Allthecausesnowmentionedfallintofourfamiliardivisions。
　　Thelettersarethecausesofsyllables，thematerialofartificialproducts，fire，&c。，ofbodies，thepartsofthewhole，andthepremissesoftheconclusion，inthesenseof'thatfromwhich'。Ofthesepairstheonesetarecausesinthesenseofsubstratum，e。g。
　　theparts，theothersetinthesenseofessence-thewholeandthecombinationandtheform。Buttheseedandthedoctorandtheadviser，andgenerallythemaker，areallsourceswhencethechangeorstationarinessoriginates，whiletheothersarecausesinthesenseoftheendorthegoodoftherest；for'thatforthesakeofwhich'
　　meanswhatisbestandtheendofthethingsthatleaduptoit。
　　Whetherwesaythe'gooditselforthe'apparentgood'makesnodifference。
　　Suchthenisthenumberandnatureofthekindsofcause。
　　Nowthemodesofcausationaremany，thoughwhenbroughtunderheadstheytoocanbereducedinnumber。For'cause'isusedinmanysensesandevenwithinthesamekindonemaybepriortoanothere。g。
　　thedoctorandtheexpertarecausesofhealth，therelation2:1andnumberoftheoctave，andalwayswhatisinclusivetowhatisparticular。Anothermodeofcausationistheincidentalanditsgenera，e。g。inoneway'Polyclitus'，inanother'sculptor'isthecauseofastatue，because'beingPolyclitus'and'sculptor'areincidentallyconjoined。Alsotheclassesinwhichtheincidentalattributeisincluded；thus'aman'couldbesaidtobethecauseofastatueor，generally，'alivingcreature'。Anincidentalattributetoomaybemoreorlessremote，e。g。supposethat'apaleman'or'amusicalman'weresaidtobethecauseofthestatue。
　　Allcauses，bothproperandincidental，maybespokenofeitheraspotentialorasactual；e。g。thecauseofahousebeingbuiltiseither'house-builder'or'house-builderbuilding'。
　　Similardistinctionscanbemadeinthethingsofwhichthecausesarecauses，e。g。of'thisstatue'orof'statue'orof'image'
　　generally，of'thisbronze'orof'bronze'orof'material'generally。
　　Sotoowiththeincidentalattributes。Againwemayuseacomplexexpressionforeitherandsay，e。g。neither'Polyclitus'nor'sculptor'but'Polyclitus，sculptor'。
　　Allthesevarioususes，however，cometosixinnumber，undereachofwhichagaintheusageistwofold。Causemeanseitherwhatisparticularoragenus，oranincidentalattributeoragenusofthat，andtheseeitherasacomplexoreachbyitself；andallsixeitherasactualoraspotential。Thedifferenceisthismuch，thatcauseswhichareactuallyatworkandparticularexistandceasetoexistsimultaneouslywiththeireffect，e。g。thishealingpersonwiththisbeing-healedpersonandthathouse-buildingmanwiththatbeing-builthouse；butthisisnotalwaystrueofpotentialcauses——thehouseandthehousebuilderdonotpassawaysimultaneously。
　　Ininvestigatingthecauseofeachthingitisalwaysnecessarytoseekwhatismostpreciseasalsoinotherthings:thusmanbuildsbecauseheisabuilder，andabuilderbuildsinvirtueofhisartofbuilding。Thislastcausethenisprior:andsogenerally。
　　Further，genericeffectsshouldbeassignedtogenericcauses，particulareffectstoparticularcauses，e。g。statuetosculptor，thisstatuetothissculptor；andpowersarerelativetopossibleeffects，actuallyoperatingcausestothingswhichareactuallybeingeffected。
　　Thismustsufficeforouraccountofthenumberofcausesandthemodesofcausation。
　　4
　　Butchancealsoandspontaneityarereckonedamongcauses:manythingsaresaidbothtobeandtocometobeasaresultofchanceandspontaneity。Wemustinquirethereforeinwhatmannerchanceandspontaneityarepresentamongthecausesenumerated，andwhethertheyarethesameordifferent，andgenerallywhatchanceandspontaneityare。
　　Somepeopleevenquestionwhethertheyarerealornot。Theysaythatnothinghappensbychance，butthateverythingwhichweascribetochanceorspontaneityhassomedefinitecause，e。g。coming'bychance'intothemarketandfindingthereamanwhomonewantedbutdidnotexpecttomeetisduetoone'swishtogoandbuyinthemarket。Similarlyinothercasesofchanceitisalwayspossible，theymaintain，tofindsomethingwhichisthecause；butnotchance，forifchancewerereal，itwouldseemstrangeindeed，andthequestionmightberaised，whyonearthnoneofthewisemenofoldinspeakingofthecausesofgenerationanddecaytookaccountofchance；whenceitwouldseemthattheytoodidnotbelievethatanythingisbychance。Butthereisafurthercircumstancethatissurprising。Manythingsbothcometobeandarebychanceandspontaneity，andalthoughknowthateachofthemcanbeascribedtosomecauseastheoldargumentsaidwhichdeniedchance，neverthelesstheyspeakofsomeofthesethingsashappeningbychanceandothersnot。Forthisreasonalsotheyoughttohaveatleastreferredtothematterinsomewayorother。
　　Certainlytheearlyphysicistsfoundnoplaceforchanceamongthecauseswhichtheyrecognized-love，strife，mind，fire，orthelike。
　　Thisisstrange，whethertheysupposedthatthereisnosuchthingaschanceorwhethertheythoughtthereisbutomittedtomentionit-andthattoowhentheysometimesusedit，asEmpedoclesdoeswhenhesaysthattheairisnotalwaysseparatedintothehighestregion，but'asitmaychance'。Atanyratehesaysinhiscosmogonythat'ithappenedtorunthatwayatthattime，butitoftenranotherwise。'Hetellsusalsothatmostofthepartsofanimalscametobebychance。
　　Therearesometoowhoascribethisheavenlysphereandalltheworldstospontaneity。Theysaythatthevortexarosespontaneously，i。e。themotionthatseparatedandarrangedinitspresentorderallthatexists。Thisstatementmightwellcausesurprise。Fortheyareassertingthatchanceisnotresponsiblefortheexistenceorgenerationofanimalsandplants，natureormindorsomethingofthekindbeingthecauseofthemforitisnotanychancethingthatcomesfromagivenseedbutanolivefromonekindandamanfromanother；andyetatthesametimetheyassertthattheheavenlysphereandthedivinestofvisiblethingsarosespontaneously，havingnosuchcauseasisassignedtoanimalsandplants。Yetifthisisso，itisafactwhichdeservestobedweltupon，andsomethingmightwellhavebeensaidaboutit。Forbesidestheotherabsurditiesofthestatement，itisthemoreabsurdthatpeopleshouldmakeitwhentheyseenothingcomingtobespontaneouslyintheheavens，butmuchhappeningbychanceamongthethingswhichastheysayarenotduetochance；whereasweshouldhaveexpectedexactlytheopposite。
　　Otherstherearewho，indeed，believethatchanceisacause，butthatitisinscrutabletohumanintelligence，asbeingadivinethingandfullofmystery。
　　Thuswemustinquirewhatchanceandspontaneityare，whethertheyarethesameordifferent，andhowtheyfitintoourdivisionofcauses。