Thechapteruponcausation59*isavigorousassertionofMill’sposition。Heacceptsthetraditionalviewofhisschool，thatcausemeansinvariablesequence；buthemakestwoveryimportantamendmentstothepreviousstatements。Asimplesequenceoftwoeventsisnotasufficientindication，howeveroftenrepeated，thattheyarecauseandeffect。Wespeak，hesays，ofaparticulardish’causing’death；buttobeaccuratewemustalsoinclude，aspartofthecause，alltheotherphenomenapresent，themanaswellasthefood，theman’sstateofhealthatthetime，andpossiblyeventhestateoftheatmosphereortheplanet。Therealcausemustincludealltherelevantphenomena。
Thecause，therefore，is，’philosophicallyspeaking，’the’sumtotaloftheconditions，’positiveandnegative，’takentogether，thewholeofthecontingenciesofeverydescription，which，beingrealised，theconsequentinvariablyfollows。’60*Mill’ssecondamendmentismadebysayingthatthecausedoesnotsignifysimply’invariableantecedence，’butalso’unconditional’
sequence。Theremaybe’invariable’sequences，suchasdayandnight——acaseoftenallegedbyReidandothers，whicharenot’unconditional。’Thesun，foranythingwecansay，mightnotrise，andthendaywouldnotfollownight。Therealcondition，therefore，isthepresenceofaluminousbodywithouttheinterpositionofanopaquescreen。61*Theseareundoubtedlymaterialimprovementsuponpreviousstatements；andthisviewbeingadmitted，itfollows，asMillsays，thatthestateofthewholeuniverseistheconsequenceofitsstateatthepreviousinstant。Knowingallthefactsandallthelawsatanytimewecouldpredictallthefuturehistoryoftheuniverse。62*Somecuriousconfusions，itmustbenoticed，resultapparentlyfromMill’suseofpopularlanguage。Themostsingularisimpliedinhisdiscussionofthequestionwhethercauseandeffectcaneverbesimultaneous。Some’causes，’hesays，leavepermanenteffects；
aswordrunsamanthrough，butitneednotremaininhisbodyinorderthathemay’continuedead。’63*The’cause’hereistakentomeanthe’thing’whichwasonceapartofasetofthings，andhasclearlyceasedtomeanthesumofalltheconditions。’Mostthings，’hecontinues，onceproduced，remainastheyaretillsomethingchangesthem。Otherthingsrequirethecontinualpresenceoftheagencieswhichproducedthem。Butsinceallchange，accordingtohim，supposesacause，itisclearthatnotonly’mostthings’butallthingsmustremainastheyaretillsomethingchangesthem。Persistenceisimpliedincausationasmuchaschange，foritismerelytheothersideofthesameprinciple。Inertiaisasmuchassumedinmechanicsasmobility；
foritisthesamethingtosaythatabodyremainsinoneplacewhenthereisnomovingforce，astosaythatwheneveritceasestoremainthereisamovingforce。ThedifferencewhichMillmeanstopointoutisthatsomechangesalterpermanentconditionsofotherchanges，aswhenamancutshisthroatandallvitalprocessescease；whilesometimesthechangeleavespermanentconditionsunaffected，aswhenamanshaveshimself，andhisvitalprocessescontinue。Butinnocaseistheeffectproduced，ashesays，afterthecausehasceased；itisalwaysproducedthroughtheactuallypresentconditions，whichmayhavecomeintotheirpresentstatethroughachangeatsomemoreorlessremoteperiod。Eachlinkinachain，accordingtothecommonmetaphor，dependsuponallthepreviouslinksandmaybesaidtohangfromthem；butthedistantlinkcanonlyactthroughtheintermediatelinks。