Again，itwouldseemimpossiblethatthesubstanceandthatof
whichitisthesubstanceshouldexistapart；how，therefore，could
theIdeas，beingthesubstancesofthings，existapart？InthePhaedo’
thecaseisstatedinthisway-thattheFormsarecausesbothofbeing
andofbecoming；yetwhentheFormsexist，stillthethingsthatshare
inthemdonotcomeintobeing，unlessthereissomethingtooriginate
movement；andmanyotherthingscomeintobeinge。g。ahouseora
ringofwhichwesaytherearenoForms。Clearly，therefore，eventhe
otherthingscanbothbeandcomeintobeingowingtosuchcausesas
producethethingsjustmentioned。
Again，iftheFormsarenumbers，howcantheybecauses？Isit
becauseexistingthingsareothernumbers，e。g。onenumberisman，
anotherisSocrates，anotherCallias？Whythenaretheonesetof
numberscausesoftheotherset？Itwillnotmakeanydifference
eveniftheformerareeternalandthelatterarenot。Butifitis
becausethingsinthissensibleworlde。g。harmonyareratiosof
numbers，evidentlythethingsbetweenwhichtheyareratiosaresome
oneclassofthings。If，then，this——thematter——issomedefinite
thing，evidentlythenumbersthemselvestoowillberatiosof
somethingtosomethingelse。E。g。ifCalliasisanumericalratio
betweenfireandearthandwaterandair，hisIdeaalsowillbea
numberofcertainotherunderlyingthings；andmanhimself，whetherit
isanumberinasenseornot，willstillbeanumericalratioof
certainthingsandnotanumberproper，norwillitbeaofnumber
merelybecauseitisanumericalratio。
Again，frommanynumbersonenumberisproduced，buthowcanone
FormcomefrommanyForms？Andifthenumbercomesnotfromthemany
numbersthemselvesbutfromtheunitsinthem，e。g。in10，000，how
isitwiththeunits？Iftheyarespecificallyalike，numerous
absurditieswillfollow，andalsoiftheyarenotalikeneitherthe
unitsinonenumberbeingthemselveslikeoneanothernorthosein
othernumbersbeingallliketoall；forinwhatwilltheydiffer，as
theyarewithoutquality？Thisisnotaplausibleview，norisit
consistentwithourthoughtonthematter。
Further，theymustsetupasecondkindofnumberwithwhich
arithmeticdeals，andalltheobjectswhicharecalled’intermediate’
bysomethinkers；andhowdotheseexistorfromwhatprinciplesdo
theyproceed？Orwhymusttheybeintermediatebetweenthethingsin
thissensibleworldandthethings-themselves？
Further，theunitsinmusteachcomefromapriorbutthisis
impossible。
Further，whyisanumber，whentakenalltogether，one？
Again，besideswhathasbeensaid，iftheunitsarediversethe
Platonistsshouldhavespokenlikethosewhosaytherearefour，or
two，elements；foreachofthesethinkersgivesthenameofelement
nottothatwhichiscommon，e。g。tobody，buttofireandearth，
whetherthereissomethingcommontothem，viz。body，ornot。Butin
factthePlatonistsspeakasiftheOnewerehomogeneouslikefire
orwater；andifthisisso，thenumberswillnotbesubstances。
Evidently，ifthereisaOneitselfandthisisafirstprinciple，
’one’isbeingusedinmorethanonesense；forotherwisethetheory
isimpossible。
Whenwewishtoreducesubstancestotheirprinciples，westate
thatlinescomefromtheshortandlongi。e。fromakindofsmalland
great，andtheplanefromthebroadandnarrow，andbodyfromthe
deepandshallow。Yethowthencaneithertheplanecontainaline，or
thesolidalineoraplane？Forthebroadandnarrowisadifferent
classfromthedeepandshallow。Therefore，justasnumberisnot
presentinthese，becausethemanyandfewaredifferentfromthese，
evidentlynootherofthehigherclasseswillbepresentinthelower。
Butagainthebroadisnotagenuswhichincludesthedeep，forthen
thesolidwouldhavebeenaspeciesofplane。Further，fromwhat
principlewillthepresenceofthepointsinthelinebederived？
Platoevenusedtoobjecttothisclassofthingsasbeinga
geometricalfiction。Hegavethenameofprincipleoftheline-and
thisheoftenposited-totheindivisiblelines。Yetthesemusthave
alimit；thereforetheargumentfromwhichtheexistenceoftheline
followsprovesalsotheexistenceofthepoint。
Ingeneral，thoughphilosophyseeksthecauseofperceptible
things，wehavegiventhisupforwesaynothingofthecausefrom
whichchangetakesitsstart，butwhilewefancywearestatingthe
substanceofperceptiblethings，weasserttheexistenceofasecond
classofsubstances，whileouraccountofthewayinwhichtheyare
thesubstancesofperceptiblethingsisemptytalk；for’sharing’，
aswesaidbefore，meansnothing。
NorhavetheFormsanyconnexionwithwhatweseetobethe
causeinthecaseofthearts，thatforwhosesakebothallmindand
thewholeofnatureareoperative，-withthiscausewhichweassert
tobeoneofthefirstprinciples；butmathematicshascometobe
identicalwithphilosophyformodernthinkers，thoughtheysaythatit
shouldbestudiedforthesakeofotherthings。Further，onemight
supposethatthesubstancewhichaccordingtothemunderliesasmatter
istoomathematical，andisapredicateanddifferentiaofthe
substance，ie。ofthematter，ratherthanmatteritself；i。e。the
greatandthesmallareliketherareandthedensewhichthephysical
philosophersspeakof，callingthesetheprimarydifferentiaeofthe
substratum；fortheseareakindofexcessanddefect。Andregarding
movement，ifthegreatandthesmallaretohemovement，evidentlythe
Formswillbemoved；butiftheyarenottobemovement，whencedid
movementcome？Thewholestudyofnaturehasbeenannihilated。
Andwhatisthoughttobeeasy-toshowthatallthingsare
one-isnotdone；forwhatisprovedbythemethodofsettingout
instancesisnotthatallthingsareonebutthatthereisaOne
itself，-ifwegrantalltheassumptions。Andnoteventhisfollows，if
wedonotgrantthattheuniversalisagenus；andthisinsome
casesitcannotbe。
Norcanitbeexplainedeitherhowthelinesandplanesandsolids
thatcomeafterthenumbersexistorcanexist，orwhatsignificance
theyhave；forthesecanneitherbeFormsfortheyarenot
numbers，northeintermediatesforthosearetheobjectsof
mathematics，northeperishablethings。Thisisevidentlya
distinctfourthclass。
Ingeneral，ifwesearchfortheelementsofexistingthings
withoutdistinguishingthemanysensesinwhichthingsaresaidto
exist，wecannotfindthem，especiallyifthesearchforthe
elementsofwhichthingsaremadeisconductedinthismanner。For
itissurelyimpossibletodiscoverwhat’acting’or’beingactedon’，
or’thestraight’，ismadeof，butifelementscanbediscoveredat
all，itisonlytheelementsofsubstances；thereforeeithertoseek
theelementsofallexistingthingsortothinkonehasthemis
incorrect。
Andhowcouldwelearntheelementsofallthings？Evidentlywe
cannotstartbyknowinganythingbefore。Forashewhoislearning
geometry，thoughhemayknowotherthingsbefore，knowsnoneofthe
thingswithwhichthesciencedealsandaboutwhichheistolearn，so
isitinallothercases。Thereforeifthereisascienceofall
things，suchassomeasserttoexist，hewhoislearningthiswill
knownothingbefore。Yetalllearningisbymeansofpremisseswhich
areeitherallorsomeofthemknownbefore，-whetherthelearningbe
bydemonstrationorbydefinitions；fortheelementsofthedefinition
mustbeknownbeforeandbefamiliar；andlearningbyinduction
proceedssimilarly。Butagain，ifthesciencewereactuallyinnate，it
werestrangethatweareunawareofourpossessionofthegreatest
ofsciences。
Again，howisonetocometoknowwhatallthingsaremadeof，and
howisthistobemadeevident？Thisalsoaffordsadifficulty；for
theremightbeaconflictofopinion，asthereisaboutcertain
syllables；somesayzaismadeoutofsanddanda，whileothers
sayitisadistinctsoundandnoneofthosethatarefamiliar。
Further，howcouldweknowtheobjectsofsensewithouthavingthe
senseinquestion？Yetweoughtto，iftheelementsofwhichall
thingsconsist，ascomplexsoundsconsistoftheclementsproperto
sound，arethesame。
Itisevident，then，evenfromwhatwehavesaidbefore，that
allmenseemtoseekthecausesnamedinthePhysics，andthatwe
cannotnameanybeyondthese；buttheyseekthesevaguely；and
thoughinasensetheyhaveallbeendescribedbefore，inasensethey
havenotbeendescribedatall。Fortheearliestphilosophyis，onall
subjects，likeonewholisps，sinceitisyoungandinitsbeginnings。
ForevenEmpedoclessaysboneexistsbyvirtueoftheratioinit。Now
thisistheessenceandthesubstanceofthething。Butitis
similarlynecessarythatfleshandeachoftheothertissuesshouldbe
theratioofitselements，orthatnotoneofthemshould；foritis
onaccountofthisthatbothfleshandboneandeverythingelsewill
exist，andnotonaccountofthematter，whichhenames，-fireand
earthandwaterandair。Butwhilehewouldnecessarilyhaveagreedif
anotherhadsaidthis，hehasnotsaiditclearly。
Onthesequestionsourviewshavebeenexpressedbefore；butlet
usreturntoenumeratethedifficultiesthatmightberaisedon
thesesamepoints；forperhapswemaygetfromthemsomehelp
towardsourlaterdifficulties。
THEinvestigationofthetruthisinonewayhard，inanother
easy。Anindicationofthisisfoundinthefactthatnooneisable
toattainthetruthadequately，while，ontheotherhand，wedonot
collectivelyfail，buteveryonesayssomethingtrueaboutthe
natureofthings，andwhileindividuallywecontributelittleor
nothingtothetruth，bytheunionofallaconsiderableamountis
amassed。Therefore，sincethetruthseemstobeliketheproverbial
door，whichnoonecanfailtohit，inthisrespectitmustbeeasy，
butthefactthatwecanhaveawholetruthandnottheparticular
partweaimatshowsthedifficultyofit。
Perhaps，too，asdifficultiesareoftwokinds，thecauseofthe
presentdifficultyisnotinthefactsbutinus。Forastheeyesof
batsaretotheblazeofday，soisthereasoninoursoultothe
thingswhicharebynaturemostevidentofall。
Itisjustthatweshouldbegrateful，notonlytothosewith
whoseviewswemayagree，butalsotothosewhohaveexpressedmore
superficialviews；forthesealsocontributedsomething，bydeveloping
beforeusthepowersofthought。Itistruethatiftherehadbeen
noTimotheusweshouldhavebeenwithoutmuchofourlyricpoetry；but
iftherehadbeennoPhrynistherewouldhavebeennoTimotheus。The
sameholdsgoodofthosewhohaveexpressedviewsaboutthetruth；for
fromsomethinkerswehaveinheritedcertainopinions，whilethe
othershavebeenresponsiblefortheappearanceoftheformer。
Itisrightalsothatphilosophyshouldbecalledknowledgeofthe
truth。Fortheendoftheoreticalknowledgeistruth，whilethatof
practicalknowledgeisactionforeveniftheyconsiderhowthings
are，practicalmendonotstudytheeternal，butwhatisrelative
andinthepresent。Nowwedonotknowatruthwithoutitscause；and
athinghasaqualityinahigherdegreethanotherthingsifin
virtueofitthesimilarqualitybelongstotheotherthingsaswell
e。g。fireisthehottestofthings；foritisthecauseoftheheat
ofallotherthings；sothatthatcausesderivativetruthstobetrue
ismosttrue。Hencetheprinciplesofeternalthingsmustbealways
mosttruefortheyarenotmerelysometimestrue，noristhereany
causeoftheirbeing，buttheythemselvesarethecauseofthebeing
ofotherthings，sothataseachthingisinrespectofbeing，so
isitinrespectoftruth。