Thereisnoconnectionwhateverbetweenthesoundoftheword’man’andthe’ideas’whichthewordexcites，beyondthefactthatthesoundhasbeenpreviouslyheardwhentheideaswereexcited。Here，then，isaphenomenontobeexplainedorgeneralised。Wehaveincountlesscasesacertainconnectionestablishedforwhichnofurtherreasoncanbeassignedthanthefactofitspreviousoccurrence。Onsuchaground，webelievethatfireburns，thatbreadiswholesome，thatstonesfall；andbutforsuchbeliefscouldknownothingoftheoutsideworld。’Contingent’truth，therefore，ortruthderivedfrommerecontact。pervades，ifitdoesnotconstitute，thewholefabricofourwholeknowledge。Toprovethatallourknowledgeisderivedfromexperienceis，accordingtoMill，toprovethatinsomesenseorotherassociationofideasliesatthebaseofallintellectualprocesses。WhenLockeintroducedachapterupon’AssociationofIdeas’intothefourtheditionofhisessay，hetreateditastheexceptionalcase。Someideashadaconnectiontraceablebyreason；otherswereonlyconnectedby’chanceandcustom。’Associationdoesnotexplainreasoning，onlythedeviationsfromreasoning。ButwithHumeandHartleytherelationisinverted。Theprinciple，insteadofbeinganexceptionalcase，issimplytheuniversalrulefromwhichlogicalconnectionmaybededucedasaspecialcase。
　　ThefactsuponwhichMillrelied，andtheaccountofthemwhichhegave，requirenoticeandembodimentinanyroundpsychology。Insomeshapeorothertheyformthestarting-pointofalllatersystems。Mill’svigorousapplicationofhisprinciple，workedoutwithimperfectappreciationandwithmanyoversights，hadtherefrom，atleast，themeritofpreparingthegroundforamorescientificmethod。
　　Inanycase，however，hisconclusions，sofarassound，mustbeplacedinadifferentframeworkoftheory。Itbecomesnecessarytodwellchieflyuponthecuriousdefectsofhistheory，iftakenashewishedittobetaken，foranultimatescientificstatement。Thefactthatthereisasynthesisandananalysisisexpressedby’association。’Butwhatmorecanwesay?
　　Whatarethe’laws’ofassociation?Unlesssomerulecanbegiven，weshallgetnothingthatcanbecalledatheory。Oneideaisnotsuggestedbytheotherthroughanylogicalprocess。Theyarestill’conjoined’butnot’connected。’
　　Theconnection，therefore，mustbegivenbysomethingdifferentfromtheideasthemselves。Nowtheorderoftheoriginal’sensations’dependsuponthe’objectsofnature，’andisthereforeleftto’physicalphilosophy。’53Theyoccur，however，eitherin’synchronous’orin’successive’order。
　　Then’ideas’springupintheorderof’sensations，’andthisisthe’generallawofassociationofideas。’54Thesynchronoussensationsproducesynchronousideasandthesuccessivesensationssuccessiveideas。Finally，thestrengthoftheassociationbetweentheideasdependsupon’thevividnessoftheassociatedfeelings，andthefrequencyoftheassociation。’55Humehadsaidthatassociationdependeduponthreeprinciples，’contiguityintimeandplace，’’causation，’and’resemblance。’Contiguityintimecorrespondstothesuccessive，andcontiguityinplacetothesynchronous，order。Causation，asBrownhadfinallyproved，56meanssimplyantecedenceandconsequence。’Resemblance’remainsandis，asMillafterwardssays，57amostimportantprinciple；butinanunluckymomentheishalfinclinedtoreduceeven’resemblance’to’contiguity。’58Resemblanceis，heevensuggests，merely’acaseoffrequency，’becausewegenerallyseelikethingstogether。Whenweseeonetreeorsheep，wegenerallyseeseveraltreesorsheep。J。S。Millmildlyremarksuponthisquaintsuggestionasthe’leastsuccessfulsimplification’inthebook。
　　Hearguesthepointgravely。Sheep，itisclear，arenotseentobelikebecausetheyoftencomposeaflock，butareconsideredtobeaflockbecausetheyareseentobelike。TodoJamesMilljustice，hedropstheargumentassoonashehasstruckitout。Itisonlyworthnoticeasshowinghisaim。’Likeness’seemstoimplyarelationdependentontheideasthemselves；
　　notpurelyexternalandarbitrary。Ifwecouldgetridoflikeness，allassociationwouldultimatelybe’contiguity。’’Thefundamentallawofassociation，’
　　ashesayselsewhere，59’isthatwhentwothingshavebeenfrequentlyfoundtogether，weneverperceiveorthinkoftheonewithoutthinkingoftheother。’Thetwoideasareassociatedastwoballsareassociatedwhentheyareinthesamebox。Sofarastheyarethemselvesconcerned，theymightbeseparatedwithoutanyalterationintheirownproperties。
　　What，then，correspondstothe’box’?Associationdependsuponrelationsoftimeandspace。Thingsareassociatedbyoccurringinsuccessionortogether；theredcolourofaroseisinthesameplacewiththeshapeoftheleaf。Thescentisperceivedatthesametimewiththecolour。Thethunderfollowsthelightning。What，then，hemightask，are’time’and’space’?Arethey’ideas’or’sensations’orqualitiesoftheobjects?
　　or，inanycase，assupplyingtheultimateprincipleofassociation，dotheynotrequireinvestigation?Beforecomingtothatproblem，however，wehavetosettleotherknottypoints。Wemustclearawayillusionswhichseemtointroducesomethingmorethanassociation。Elementsofthoughtnotatfirstsightexpressiblesimplyintermsofsensationsandideasmustbeanalysedtoshowthattheyareonlydisguisesfordifferentcombinationsofthefacts。Reasoning，accordingtomostlogicians，supposes，first，concepts，andthereforesomeprocessofclassificationoftheobjectsofthought；and，secondly，someprocessofcombiningtheseconceptstobringouthithertounknowntruths。What，then，isthemeaningofthegeneralorabstractsymbolsemployedintheprocess?Mill’sprovisionofrawmaterialsconsistssofarofsensationsandideas，whichareworkedupsoastoform’clusters’thewordistakenfromHartleyand’trains。’Thiscorrespondstosynchronousandsuccessiveassociations。Howdoesthelogicalterminologyexpressthese’clusters’and’trains’?Millanswersbyatheoryof’naming。’
　　Languagefulfilstwopurposes；itisrequiredinordertomakeourideasknowntoothers；andinordertofixourownideas。Ideasarefluctuating，transitory，and’comeintothemindunbidden。’Wemustcatchandmakeanoteoftheseshiftingcrowdsofimpalpableentities。Wethereforeputmarksuponthesimplesensationsoruponthe’clusters。’Weticketthemasatradesmanticketsbundlesofgoodsinhiswarehouse，andcanrefertothemforourownpurposesorthoseofothers。Asthenumberofobjectstobemarkedisenormous，astherearecountlessideasandclustersandclustersofclustersofendlessvarietytobearrangedinvariousways，onemainobjectofnamingiseconomy。Asinglewordhastobeusedtomarkagreatnumberofindividuals。Thiswillaccountforsuchgeneralnamesasarerepresentedbynoun-substantives；man，horse，dog，andsoforth。
　　Millthenproceeds，withthehelpofHorneTooke，toexplaintheothergrammaticalforms。Anadjectiveisanotherkindofnounmakingacrossdivision。Verbs，again，areadjectivesmarkingothersetsoffacts，andenablingustogetridofthenecessityofusinganewmarkforeveryindividualorconceivablecombinationintoclusters。J。S。Millremarksthatthisomitsthespecialfunctionofverbs——their’employmentinpredication。’60JamesMill，however，hashisownviewof’predication。’’Man’isamarkofJohn，Peter，Thomas，andtherest。WhenIsay’Johnisaman，’Imeanthat’manisanothermarktothatideaofwhichJohnisamark。’61Iamthenabletomakeastatementwhichwillapplytoalltheindividuals，andsavethetroubleofrepeatingtheassertionabouteach。’Predication，’
　　therefore，issimplyasubstitutionofonenameforanother。So，forexample，arithmeticissimplynaming。WhatIcalltwoandtwo，Ialsocallfour。
　　Theseriesofthoughtsinthiscaseismerely’aseriesofnamesapplicabletothesamethingandmeaningthesamething。’62Thisdoctrine，asJ。S。Millremarks，isderivedfromHobbes，whomLeibnizinconsequencecalledplusquamnominalis。63MybeliefthattwoandtwomakefourexplainswhyIgivethesamenametocertainnumbers；butthegivingthenamedoesnotexplainthebelief。Meanwhile，ifaclassnamebesimplythemarkwhichisputuponabundleofthings，wehavegotridofapuzzle。
　　Milltriumphsovertheunfortunaterealistswhoheldthataclassmeantamysteriousentity，existingsomewhereapartfromalltheindividualsinwhichitisembodied。Thereisreallynothingmysterious；anameisfirstthemarkofanindividual，theindividualcorrespondingtoa’cluster’
　　orasetof’simpleideas，concretedintoacomplexidea。’64Thenthenameandthecomplexideaareassociatedreciprocally；each’callsup’theother。Thecomplexideais’associated’withotherresemblingideas。
　　Thenamebecomesatalismancallinguptheideasofanindefinitenumberofresemblingindividuals，andthenameappliedtooneinthefirstinstancebecomesamarkwhichcallsupall，or，ashesays，isthe’nameofthewholecombination。’Classification，therefore，’ismerelyaprocessofnaming，andisallresolvableintoassociation。’65Thepeculiarityofthistheory，ashiscommentatorsagainremark，isthatitexpresslyomitsanyreferencetoabstraction。Theclasssimplymeanstheaggregateofresemblingindividualswithoutanyselectionofthecommonattributeswhichare，inJ。S。Mill’sphrase，’connoted’bytheclass-name。Abstraction，asJamesMillexplains，isasubsidiaryprocess，correspondingtothe’formationofsub-species。’66
　　Millhasnowshownhowthevariousformsoflanguagecorrespondtoideas，formedintoclustersofvariousordersbytheprincipleofassociation。Thenextstepwillnaturallybetoshowhowtheseclustersareconnectedintheprocessofreasoning。
　　Herethedifficultyaboutpredicationrecurs。J。S。Mill67remarksthathisfather’stheoryofpredicationconsistentlyomits’theelementBelief。’WhenIsay，’Johnisaman，’Imakeanaffirmationorassertabelief。Idonotsimplymeantocallupinthemindofmyheareracertain’cluster’ortwocoincidentclustersofideas，buttoconveyknowledgeoftruths。Theomissionofreferencetobeliefiscertainlynotrifle。
　　Millhasclassifiedthevariousideasandcombinationsofideaswhichareusedinjudgment，buttheprocessofjudgmentitselfseemstohaveslippedoutofaccount。Hemayhavegivenus，orbeabletogiveus，areasonedcatalogueofthecontentsofourminds，buthasnotexplainedhowtheminditselfacts。Itisamerepassiverecipientofideas，orratheritselfaclusterofideascoheringinvariousways，withoutenergyofitsown。
　　Oneidea，ashetellsus，callsupanother’byitsownassociatingpower。’68Ideasarethingswhichsomehowsticktogetherandreviveeachother，withoutreferencetothemindinwhichtheyexistorwhichtheycompose。Thisexplainshisfrequentinsistenceupononeassertion。Asweapproachthequestionofjudgmenthefindsitessential。’Havingasensationandhavingafeeling，’
　　hesays，’arenottwothings。’To’feelanideaandbeconsciousofthatfeelingarenottwothings；thefeelingandtheconsciousnessarebuttwonamesforthesamething。’69So，again，’tohaveasensationandtobelievethatwehaveit，arenotdistinguishablethings。’70Locke’sreflectionthusbecomesnothingbutsimpleconsciousness，andhavingafeelingisthesameasattendingtoit。71Thepointisessential。
　　Itamountstosayingthatwecanspeakofathoughtasthoughitweresimplyathing。