1Firstthenwithregardtowhatwementionedfirst，doesit
　　belongtooneortomoresciencestoinvestigateallthekindsof
　　causes？Howcoulditbelongtoonesciencetorecognizetheprinciples
　　ifthesearenotcontrary？
　　Further，therearemanythingstowhichnotalltheprinciples
　　pertain。Forhowcanaprincipleofchangeorthenatureofthegood
　　existforunchangeablethings，sinceeverythingthatinitselfand
　　byitsownnatureisgoodisanend，andacauseinthesensethatfor
　　itssaketheotherthingsbothcometobeandare，andsinceanendor
　　purposeistheendofsomeaction，andallactionsimplychange？Soin
　　thecaseofunchangeablethingsthisprinciplecouldnotexist，nor
　　couldtherebeagooditself。Thisiswhyinmathematicsnothingis
　　provedbymeansofthiskindofcause，noristhereany
　　demonstrationofthiskind-’becauseitisbetter，orworse’；indeedno
　　oneevenmentionsanythingofthekind。Andsoforthisreasonsomeof
　　theSophists，e。g。Aristippus，usedtoridiculemathematics；forin
　　theartshemaintained，evenintheindustrialarts，e。g。in
　　carpentryandcobbling，thereasonalwaysgivenis’becauseitis
　　better，orworse，’butthemathematicalsciencestakenoaccountof
　　goodsandevils。
　　Butifthereareseveralsciencesofthecauses，andadifferent
　　scienceforeachdifferentprinciple，whichofthesesciencesshould
　　besaidtobethatwhichweseek，orwhichofthepeoplewhopossess
　　themhasthemostscientificknowledgeoftheobjectinquestion？
　　Thesamethingmayhaveallthekindsofcauses，e。g。themovingcause
　　ofahouseistheartorthebuilder，thefinalcauseisthe
　　functionitfulfils，thematterisearthandstones，andtheformis
　　thedefinition。Tojudgefromourpreviousdiscussionofthe
　　questionwhichofthesciencesshouldbecalledWisdom，thereis
　　reasonforapplyingthenametoeachofthem。Forinasmuchasitis
　　mostarchitectonicandauthoritativeandtheothersciences，like
　　slavewomen，maynotevencontradictit，thescienceoftheendand
　　ofthegoodisofthenatureofWisdomfortheotherthingsarefor
　　thesakeoftheend。Butinasmuchasitwasdescribed’asdealing
　　withthefirstcausesandthatwhichisinthehighestsenseobjectof
　　knowledge，thescienceofsubstancemustbeofthenatureofWisdom。
　　Forsincemenmayknowthesamethinginmanyways，wesaythathewho
　　recognizeswhatathingisbyitsbeingsoandsoknowsmorefully
　　thanhewhorecognizesitbyitsnotbeingsoandso，andinthe
　　formerclassitselfoneknowsmorefullythananother，andheknows
　　mostfullywhoknowswhatathingis，nothewhoknowsitsquantityor
　　qualityorwhatitcanbynaturedoorhavedonetoit。Andfurtherin
　　allcasesalsowethinkthattheknowledgeofeachevenofthe
　　thingsofwhichdemonstrationispossibleispresentonlywhenweknow
　　whatthethingis，e。g。whatsquaringarectangleis，viz。thatit
　　isthefindingofamean；andsimilarlyinallothercases。Andwe
　　knowaboutbecomingsandactionsandabouteverychangewhenweknow
　　thesourceofthemovement；andthisisotherthanandopposedto
　　theend。Thereforeitwouldseemtobelongtodifferentsciencesto
　　investigatethesecausesseverally。
　　But2，takingthestarting-pointsofdemonstrationaswellas
　　thecauses，itisadisputablequestionwhethertheyaretheobjectof
　　onescienceorofmorebythestarting-pointsofdemonstrationImean
　　thecommonbeliefs，onwhichallmenbasetheirproofs；e。g。that
　　everythingmustbeeitheraffirmedordenied，andthatathing
　　cannotatthesametimebeandnotbe，andallothersuch
　　premisses:-thequestioniswhetherthesamesciencedealswiththemas
　　withsubstance，oradifferentscience，andifitisnotone
　　science，whichofthetwomustbeidentifiedwiththatwhichwenow
　　seek-Itisnotreasonablethatthesetopicsshouldbetheobjectof
　　onescience；forwhyshoulditbepeculiarlyappropriatetogeometry
　　ortoanyothersciencetounderstandthesematters？Ifthenit
　　belongstoeverysciencealike，andcannotbelongtoall，itisnot
　　peculiartothesciencewhichinvestigatessubstances，anymorethan
　　toanyotherscience，toknowaboutthesetopics-And，atthesame
　　time，inwhatwaycantherebeascienceofthefirstprinciples？
　　Forweareawareevennowwhateachoftheminfactisatleast
　　evenothersciencesusethemasfamiliar；butifthereisa
　　demonstrativesciencewhichdealswiththem，therewillhavetobe
　　anunderlyingkind，andsomeofthemmustbedemonstrableattributes
　　andothersmustbeaxiomsforitisimpossiblethatthereshouldbe
　　demonstrationaboutallofthem；forthedemonstrationmuststart
　　fromcertainpremissesandbeaboutacertainsubjectandprove
　　certainattributes。Thereforeitfollowsthatallattributesthat
　　areprovedmustbelongtoasingleclass；foralldemonstrative
　　sciencesusetheaxioms。
　　Butifthescienceofsubstanceandthesciencewhichdealswith
　　theaxiomsaredifferent，whichofthemisbynaturemore
　　authoritativeandprior？Theaxiomsaremostuniversalandare
　　principlesofallthings。Andifitisnotthebusinessofthe
　　philosopher，towhomelsewillitbelongtoinquirewhatistrueand
　　whatisuntrueaboutthem？
　　3Ingeneral，doallsubstancesfallunderonescienceor
　　undermorethanone？Ifthelatter，towhatsortofsubstanceisthe
　　presentsciencetobeassigned？-Ontheotherhand，itisnot
　　reasonablethatonescienceshoulddealwithall。Forthentherewould
　　beonedemonstrativesciencedealingwithallattributes。Forever
　　demonstrativescienceinvestigateswithregardtosomesubjectits
　　essentialattributes，startingfromthecommonbeliefs。Thereforeto
　　investigatetheessentialattributesofoneclassofthings，
　　startingfromonesetofbeliefs，isthebusinessofonescience。
　　Forthesubjectbelongstoonescience，andthepremissesbelongto
　　one，whethertothesameortoanother；sothattheattributesdoso
　　too，whethertheyareinvestigatedbythesesciencesorbyone
　　compoundedoutofthem。
　　5Further，doesourinvestigationdealwithsubstancesalone
　　oralsowiththeirattributes？Imeanforinstance，ifthesolidis
　　asubstanceandsoarelinesandplanes，isitthebusinessofthe
　　samesciencetoknowtheseandtoknowtheattributesofeachofthese
　　classestheattributesaboutwhichthemathematicalsciencesoffer
　　proofs，orofadifferentscience？Ifofthesame，thescienceof
　　substancealsomustbeademonstrativescience，butitisthoughtthat
　　thereisnodemonstrationoftheessenceofthings。Andifofanother，
　　whatwillbethesciencethatinvestigatestheattributesof
　　substance？Thisisaverydifficultquestion。
　　4Further，mustwesaythatsensiblesubstancesaloneexist，
　　orthatthereareothersbesidesthese？Andaresubstancesofonekind
　　orarethereinfactseveralkindsofsubstances，asthosesaywho
　　asserttheexistencebothoftheFormsandoftheintermediates，
　　withwhichtheysaythemathematicalsciencesdeal？-Thesenseinwhich
　　wesaytheFormsarebothcausesandself-dependentsubstanceshas
　　beenexplainedinourfirstremarksaboutthem；whilethetheory
　　presentsdifficultiesinmanyways，themostparadoxicalthingof
　　allisthestatementthattherearecertainthingsbesidesthosein
　　thematerialuniverse，andthatthesearethesameassensible
　　thingsexceptthattheyareeternalwhilethelatterareperishable。
　　Fortheysaythereisaman-himselfandahorse-itselfand
　　health-itself，withnofurtherqualification，-aprocedurelikethatof
　　thepeoplewhosaidtherearegods，butinhumanform。Fortheywere
　　positingnothingbuteternalmen，norarethePlatonistsmakingthe
　　Formsanythingotherthaneternalsensiblethings。
　　Further，ifwearetopositbesidestheFormsandthesensibles
　　theintermediatesbetweenthem，weshallhavemanydifficulties。For
　　clearlyonthesameprincipletherewillbelinesbesidesthe
　　lines-themselvesandthesensiblelines，andsowitheachoftheother
　　classesofthings；sothatsinceastronomyisoneofthese
　　mathematicalsciencestherewillalsobeaheavenbesidesthesensible
　　heaven，andasunandamoonandsowiththeotherheavenlybodies
　　besidesthesensible。Yethowarewetobelieveinthesethings？Itis
　　notreasonableeventosupposesuchabodyimmovable，buttosuppose
　　itmovingisquiteimpossible-Andsimilarlywiththethingsof
　　whichopticsandmathematicalharmonicstreat；forthesealsocannot
　　existapartfromthesensiblethings，forthesamereasons。Forif
　　therearesensiblethingsandsensationsintermediatebetweenFormand
　　individual，evidentlytherewillalsobeanimalsintermediate
　　betweenanimals-themselvesandtheperishableanimals-Wemightalso
　　raisethequestion，withreferencetowhichkindofexistingthingswe
　　mustlookforthesesciencesofintermediates。Ifgeometryisto
　　differfrommensurationonlyinthis，thatthelatterdealswith
　　thingsthatweperceive，andtheformerwiththingsthatarenot
　　perceptible，evidentlytherewillalsobeascienceotherthan
　　medicine，intermediatebetweenmedical-science-itselfandthis
　　individualmedicalscience，andsowitheachoftheothersciences。
　　Yethowisthispossible？Therewouldhavetobealsohealthythings
　　besidestheperceptiblehealthythingsandthehealthy-itself——Andat
　　thesametimenoteventhisistrue，thatmensurationdealswith
　　perceptibleandperishablemagnitudes；forthenitwouldhaveperished
　　whentheyperished。
　　Butontheotherhandastronomycannotbedealingwithperceptible
　　magnitudesnorwiththisheavenaboveus。Forneitherare
　　perceptiblelinessuchlinesasthegeometerspeaksofforno
　　perceptiblethingisstraightorroundinthewayinwhichhe
　　defines’straight’and’round’；forahooptouchesastraightedgenot
　　atapoint，butasProtagorasusedtosayitdid，inhisrefutationof
　　thegeometers，norarethemovementsandspiralorbitsintheheavens
　　likethoseofwhichastronomytreats，norhavegeometricalpoints
　　thesamenatureastheactualstars-Nowtherearesomewhosaythat
　　theseso-calledintermediatesbetweentheFormsandtheperceptible
　　thingsexist，notapartfromtheperceptiblethings，however，butin
　　these；theimpossibleresultsofthisviewwouldtaketoolongto
　　enumerate，butitisenoughtoconsiderevensuchpointsasthe
　　following:-Itisnotreasonablethatthisshouldbesoonlyinthe
　　caseoftheseintermediates，butclearlytheFormsalsomightbein
　　theperceptiblethings；forbothstatementsarepartsofthesame
　　theory。Further，itfollowsfromthistheorythattherearetwosolids
　　inthesameplace，andthattheintermediatesarenotimmovable，since
　　theyareinthemovingperceptiblethings。Andingeneraltowhat
　　purposewouldonesupposethemtoexistindeed，buttoexistin
　　perceptiblethings？Forthesameparadoxicalresultswillfollowwhich
　　wehavealreadymentioned；therewillbeaheavenbesidesthe
　　heaven，onlyitwillbenotapartbutinthesameplace；whichis
　　stillmoreimpossible。
　　6Apartfromthegreatdifficultyofstatingthecasetrulywith
　　regardtothesematters，itisveryhardtosay，withregardtothe
　　firstprinciples，whetheritisthegenerathatshouldbetakenas
　　elementsandprinciples，orrathertheprimaryconstituentsofa
　　thing；e。g。itistheprimarypartsofwhicharticulatesoundsconsist
　　thatarethoughttobeelementsandprinciplesofarticulatesound，
　　notthecommongenus-articulatesound；andwegivethenameof
　　’elements’tothosegeometricalpropositions，theproofsofwhich
　　areimpliedintheproofsoftheothers，eitherofallorofmost。
　　Further，boththosewhosaythereareseveralelementsofcorporeal
　　thingsandthosewhosaythereisone，saythepartsofwhichbodies
　　arecompoundedandconsistareprinciples；e。g。Empedoclessaysfire
　　andwaterandtherestaretheconstituentelementsofthings，but
　　doesnotdescribetheseasgeneraofexistingthings。Besidesthis，if
　　wewanttoexaminethenatureofanythingelse，weexaminetheparts
　　ofwhich，e。g。abedconsistsandhowtheyareputtogether，and
　　thenweknowitsnature。
　　Tojudgefromthesearguments，then，theprinciplesofthings
　　wouldnotbethegenera；butifweknoweachthingbyits
　　definition，andthegeneraaretheprinciplesorstarting-pointsof
　　definitions，thegeneramustalsobetheprinciplesofdefinable
　　things。Andiftogettheknowledgeofthespeciesaccordingto
　　whichthingsarenamedistogettheknowledgeofthings，thegenera
　　areatleaststarting-pointsofthespecies。Andsomealsoofthose
　　whosayunityorbeing，orthegreatandthesmall，areelementsof
　　things，seemtotreatthemasgenera。
　　But，again，itisnotpossibletodescribetheprinciplesin
　　bothways。Fortheformulaoftheessenceisone；butdefinitionby
　　generawillbedifferentfromthatwhichstatestheconstituent
　　partsofathing。