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。