IwillventuretosayanotherwordupontheuniformityofNaturedifficulty。Itiseasy，saysMill，toconceiveofthingshappeningatrandom。Itis，indeed，inonesenseperfectlyeasy。
’Raw’things，orunanalysedconcreteevents，dohappenatrandom，thatis，withoutuniformantecedents。Nothingiseasierthantothinkofthingswithoutthinkingoftheircauses。Theprimitivemind，andeventhecultivatedmind，maysimplywatchtheseriesofeventswithouttryingtofindanyconnectionorindulginginanyreasoning。Butthisisquitedifferentfromthinkingofthingsaspositivelyuncaused。Aphenomenonsuddenlyintrudeswithoutwarning。Imayacceptitwithoutaskingwhenceitcomes，orwhy。Butthereisnoreallypositivemeaninginthestatementthatitiscausedby’nothing。’Itdoesnotimplyacontradiction，suchasoccurswhenIputtogetherthewordscrookedandstraight，roundandsquare；butitrepresentsnointelligiblemeaning。Itcorrespondstoasimpleabsenceofthought。WhenIspeakoftheuniformityofNature，ImeansimplytoindicateaconditionofthinkingaboutNatureatall。Imayceasetoreasonortothink；butifIthink，Imustthinkcoherently，andassumewhathasbeencalledthe’UniversalPostulate。’92*Thephraseseemstometobeinadequate；andatanyrateitisapostulatewiththispeculiarity，thatwecannotmakeanyother。Todenyitistoallowcontradictorystatementsonthemostintimatetissueofourreasoning。Itisasimpossibletodowithoutitastodowithouttheprincipleofcontradictioninpurelogic。Ithelpsustonopositivestatement；butitisawarningthatourstatementsmustbecoherent。Hence，wemustallowthemindtohavethismodestcapacityforworkingupitsexperience。Ifitstartsfromsounprejudicedapointofviewastoadmitcontradictions，orallowofinconsistentstatementsaboutthings，itwillneverbeabletogetanywhere，andwhenMillhasreducedallourknowledgetotherelationsbetweenideasinthemind，itisreallyquiteinconsistenttoallowthemindnopowerofputtingideastogether。Withoutsuchapoweritisdifficulttosaywhatisevenmeantbytheperceptionof’coexistences’and’sequences。’Theprogressofknowledge，then，mustbeunderstoodascorrespondingtotheprocessbywhichthechaosofimpressionsandideasisgraduallyreducedtocosmos；
andasstartingfromapositioninwhichnocausehasbeenyetdiscoveredforgreatmassesoffacts，notfromapositioninwhich’nocause’isanequallyprobablealternativewith’somecause。’Toreasonatallaboutfactsistoarrangetheminorderofcausation，andtosupposethemashavingcertaintime-andspace-relations。Togetbehindthatprimitivegermofreasoningisreallytomakelogicimpossiblefromthestart。Mill’sdreadofaprioriintuitionsandnecessaryresultsthusledhimintoperfectlygratuitousdifficulties。Grantingthe’necessity’ofarithmeticorgeometry，itisstillahypotheticalnecessity。Itcannevertakeusbeyondexperience。Suchtheoremscannottellusoftheexistenceofasinglethingorofitsnature。Theycanonlysaythatifweseethingsinspacetheywillhavecertainrelationswhicharededuciblefromthespecialconfirmation。
Withoutthatpowertheuniversewouldbeundecipherable，butwithitourknowledgestillhasthroughoutacompletelyempiricalbase。Notasinglestatementoffactcanbemadewhichisnotderivedfrom，andjustifiedby，experience；norcanourexperienceevergetbeyondsayingthatanygivensectionofthewholeisdevelopedoutof，anddevelopsinto，precedingandsucceedingsections。
VIII。THEFOURMETHODS