InofferingtothepublicanewbookuponasubjectsotriteasEthics，itseemsdesirabletoindicateclearlyattheoutsetitsplanandpurpose。Itsdistinctivecharacteristicsmaybefirstgivennegatively。Itisnot，inthemain，metaphysicalorpsychological:atthesametimeitisnotdogmaticordirectlypractical:itdoesnotdeal，exceptbywayofillustration，withthehistoryofethicalthought:inasenseitmightbesaidtobenotevencritical，sinceitisonlyquiteincidentallythatitoffersanycriticismofthesystemsofindividualmoralists。Itclaimstobeanexamination，atonceexpositoryandcritical，ofthedifferentmethodsofobtainingreasonedconvictionsastowhatoughttobedonewhicharetobefound——eitherexplicitorimplicit-inthemoralconsciousnessofmankindgenerallyandwhich，fromtimetotime，havebeendeveloped，eithersinglyorincombination，byindividualthinkers，andworkedupintothesystemsnowhistorical。
　　IhaveavoidedtheinquiryintotheOriginoftheMoralFaculty——whichhasperhapsoccupiedadisproportionateamountoftheattentionofmodernmoralists——bythesimpleassumptionwhichseemstobemadeimplicitlyinallethicalreasoningthatthereissomethingunderanygivencircumstanceswhichitisrightorreasonabletodo，andthatthismaybeknown。Ifitbeadmittedthatwenowhavethefacultyofknowingthis，itappearstomethattheinvestigationofthehistoricalantecedentsofthiscognition，andofitsrelationtootherelementsofthemind，nomoreproperlybelongstoEthicsthanthecorrespondingquestionsastothecognitionofSpacebelongtoGeometry。Imake，however，nofurtherassumptionastothenatureoftheobjectofethicalknowledge:andhencemytreatiseisnotdogmatic:allthedifferentmethodsdevelopedinitareexpoundedandcriticisedfromaneutralposition，andasimpartiallyaspossible。Andthus，thoughmytreatmentofthesubjectis，inasense，morepracticalthanthatofmanymoralists，sinceIamoccupiedfromfirsttolastinconsideringhowconclusionsaretoberationallyreachedinthefamiliarmatterofourcommondailylifeandactualpractice；still，myimmediateobject-toinvertAristotle’sphrase——isnotPracticebutKnowledge。Ihavethoughtthatthepredominanceinthemindsofmoralistsofadesiretoedifyhasimpededtherealprogressofethicalscience:andthatthiswouldbebenefitedbyanapplicationtoitofthesamedisinterestedcuriositytowhichwechieflyowethegreatdiscoveriesofphysics。ItisinthisspiritthatIhaveendeavouredtocomposethepresentwork:andwiththisviewIhavedesiredtoconcentratethereader’sattention，fromfirsttolast，notonthepracticalresultstowhichourmethodslead，butonthemethodsthemselves。Ihavewishedtoputasidetemporarilytheurgentneedwhichweallfeeloffindingandadoptingthetruemethodofdeterminingwhatweoughttodo；andtoconsidersimplywhatconclusionswillberationallyreachedifwestartwithcertainethicalpremises，andwithwhatdegreeofcertaintyandprecision。
　　Ioughttomentionthatchapteriv。ofBooki。
　　hasbeenreprintedwithconsiderablemodificationsfromtheContemporaryReview，inwhichitoriginallyappearedasanarticleon``PleasureandDesire’’。AndIcannotconcludewithoutatributeofthankstomyfriendMr。Venn，towhosekindnessinacceptingthesomewhatlaborioustaskofreadingandcriticisingmywork，bothbeforeandduringitspassagethroughthepress，Iamindebtedforseveralimprovementsinmyexposition。
　　Inpreparingthisworkforthesecondedition，Ihavefounditdesirabletomakenumerousalterationsandadditions。Indeedtheextentwhichthesehavereachedissoconsiderable，thatIhavethoughtitwelltopublishtheminaseparateform，fortheuseofpurchasersofmyfirstedition。OnoneortwopointsIhavetoacknowledgeacertainchangeofview；whichispartlyatleastduetocriticism。Forinstance，inchap。iv。ofBooki。on``PleasureandDesire’’，whichhasbeenagooddealcriticisedbyProf。Bainandothers，althoughIstillretainmyformeropiniononthepsychologicalquestionatissue，IhavebeenledtotakeadifferentviewoftherelationofthisquestiontoEthics；andinfact§；1ofthischapterasitatpresentstandsdirectlycontradictsthecorrespondingpassageintheformeredition。Soagain，asregardsthefollowingchapter，on`Free-Will’，thoughIhavenotexactlyfoundthatthecommentswhichithascalledforthhaveremovedmydifficultiesindealingwiththistime-honouredproblem，IhavebecomeconvincedthatI
　　oughtnottohavecrudelyobtrudedthesedifficultiesonthereader，whileprofessedlyexcludingtheconsiderationofthemfrommysubject。InthepresenteditionthereforeIhavecarefullylimitedmyselftoexplainingandjustifyingtheviewthatItakeofthepracticalaspectofthequestion。
　　Ihavefurtherbeenled，throughstudyoftheTheoryofEvolutioninitsapplicationtopractice，toattachsomewhatmoreimportancetothistheorythanIhadpreviouslydone；andalsoinseveralpassagesofBooksiii。
　　andiv。tosubstitute`well-being’for`happiness’，inmyexpositionofthatimplicitreferencetosomefurtherendandstandardwhichreflectionontheMoralityofCommonSensecontinuallybringsintoview。ThislatterchangehoweverasIexplainintheconcludingchapterofBookiii。isnotultimatelyfoundtohaveanypracticaleffect。Ihavealsomodifiedmyviewof`objectiverightness’，asthereaderwillseebycomparingBooki。chap。i。§；3withthecorrespondingpassageintheformereditionbuthereagainthealterationhasnomaterialimportance。InmyexpositionoftheUtilitarianprincipleBookiv。chap。i。Ihaveshortenedthecumbrousphrase’greatesthappinessofthegreatestnumber’byomitting——asitsauthorultimatelyadvised——thelastfourwords。Andfinally，IhaveyieldedasfarasIcouldtotheobjectionsthathavebeenstronglyurgedagainsttheconcludingchapterofthetreatise。Themaindiscussionthereincontainedstillseemstomeindispensabletothecompletenessofthework；butI
　　haveendeavouredtogivethechapteranewaspectbyalteringitscommencement，andomittingmostoftheconcludingparagraph。
　　Thegreaterpart，however，ofthenewmatterinthiseditionismerelyexplanatoryandsupplementary。
　　IhaveendeavouredtogiveafullerandcleareraccountofmyviewsonanypointsonwhichIeitherhavemyselfseenthemtobeambiguouslyorinadequatelyexpressed，orhavefoundbyexperiencethattheywereliabletobemisunderstood。ThusinBooki。chap。ii。IhavetriedtofurnisharathermoreinstructiveaccountthanmyfirsteditioncontainedofthemutualrelationsofEthicsandPolitics。Again，evenbeforetheappearanceofMr。LeslieStephen’sinterestingreviewinFraserMarch1875，Ihadseenthedesirabilityofexplainingfurthermygeneralviewofthe`PracticalReason’，andofthefundamentalnotionsignifiedbytheterms`right’，`ought’，etc。WiththisobjectIhaveentirelyrewrittenchap。
　　iii。ofBooki。，andmadeconsiderablechangesinchap。i。Elsewhere，asinchaps。vi。andix。ofBooki。，andchap。viofBookii，Ihavealteredchieflyinordertomakemyexpositionsmoreclearandsymmetrical。ThisispartlythecasewiththeconsiderablechangesthatIhavemadeinthefirstthreechaptersofBookiii。；butIhavealsotriedtoobviatetheobjectionsbroughtbyProfessorCalderwoodagainstthefirstofthesechapters。
　　ThemainpartofthisBookchaps。iv——xii。hasbeenbutslightlyaltered；
　　butinchap。xiii。on`PhilosophicalIntuitionism’，whichhasbeensuggestivelycriticisedbymorethatonewriter，Ihavethoughtitexpedienttogiveamoredirectstatementofmyownopinions；insteadofconfiningmyselfasIdidinthefirsteditiontocommentsonthoseofothermoralists。
　　Chap。xiv。againhasbeenconsiderablymodified；chieflyinordertointroduceintoitthesubstanceofcertainportionsofanarticleon`HedonismandUltimateGood’，whichIpublishedinMindNo。5。InBookiv。thechangesbesidesthoseabovementionedhavebeeninconsiderable；andhavebeenchieflymadeinordertoremoveamisconceptionwhichIshallpresentlynotice，astomygeneralattitudetowardsthethreeMethodswhichIamprincipallyoccupiedinexamining。
　　Inrevisingmywork，Ihaveendeavouredtoprofitasmuchaspossiblebyallthecriticismsonitthathavebeenbroughttomynotice，whetherpublicorprivate。Ihavefrequentlydeferredtoobjections，evenwhentheyappearedtomeunsound，ifIthoughtIcouldavoidcontroversybyalterationstowhichIwasmyselfindifferent。
　　WhereIhavebeenunabletomakethechangesrequired，Ihaveusuallyreplied，inthetextorthenotes，tosuchcriticismsashaveappearedtomeplausible，orinanywayinstructive。Insodoing，Ihavesometimesreferredbynametoopponents，whereIthoughtthat，fromtheirrecognisedpositionasteachersofthesubject，thiswouldgiveadistinctadditionofinteresttothediscussion；butIhavebeencarefultoomitsuchreferencewhereexperiencehasshownthatitwouldbelikelytocauseoffence。ThebookisalreadymorecontroversialthanIcouldwish；andIhavethereforeavoidedencumberingitwithanypolemicsofpurelypersonalinterest。ForthisreasonIhavegenerallyleftunnoticedsuchcriticismsashavebeenduetomeremisapprehensions，againstwhichIthoughtIcouldeffectuallyguardinthepresentedition。
　　Thereis，however，onefundamentalmisunderstanding，onwhichitseemsdesirabletosayafewwords。Ifindthatmorethanonecritichasoverlookedordisregardedtheaccountoftheplanofmytreatise，givenintheoriginalprefaceandin§；5oftheintroductorychapter:andhasconsequentlysupposedmetobewritingasanassailantoftwoofthemethodswhichI
　　chieflyexamine，andadefenderofthethird。ThusoneofmyreviewersseemstoregardBookiii。onIntuitionismascontainingmerehostilecriticismfromtheoutside:anotherhasconstructedanarticleonthesuppositionthatmyprincipalobjectisthe`suppressionofEgoism’:athirdhasgonetothelengthofapamphletundertheimpressionapparentlythatthe`mainargument’ofmytreatiseisademonstrationofUniversalisticHedonism。
　　Iamconcernedtohavecausedsomuchmisdirectionofcriticism:andI
　　havecarefullyalteredinthiseditionthepassageswhichIperceivetohavecontributedtoit。ThemoralitythatIexamineinBookiii。ismyownmoralityasmuchasitisanyman’s:itis，asIsay，the`MoralityofCommonSense’，whichIonlyattempttorepresentinsofarasIshareit；Ionlyplacemyselfoutsideiteither1temporarily，forthepurposeofimpartialcriticism，or2insofarasIamforcedbeyonditbyapracticalconsciousnessofitsincompleteness。Ihavecertainlycriticisedthismoralityunsparingly:butIconceivemyselftohaveexposedwithequalunreservethedefectsanddifficultiesofthehedonisticmethodcf。especiallychaps。iii。，iv。ofBookii。，andchap。v。ofBookiv。。Andasregardsthetwohedonisticprinciples，IdonotholdthereasonablenessofaimingathappinessgenerallywithanystrongerconvictionthanIdothatofaimingatone’sown。Itwasnopartofmyplantocallspecialattentiontothis``DualismofthePracticalReason’’asIhaveelsewherecalledit:butIamsurprisedattheextenttowhichmyviewhasperplexedeventhoseofmycriticswhohaveunderstoodit。IhadimaginedthattheywouldreadilytraceittothesourcefromwhichIlearntit，Butler’swell-knownSermons。
　　IholdwithButlerthat``ReasonableSelf-loveandConsciencearethetwochieforsuperiorprinciplesinthenatureofman’’，eachofwhichweareundera``manifestobligation’’toobey:andIdo，notIbelievediffermateriallyfromButlerinmyvieweitherofreasonableself-love，or——theologyapart——ofitsrelationtoconscience。Nor，again，doIdifferfromhiminregardingconscienceasessentiallyafunctionofthepracticalReason:
　　``moralprecepts’’，hesaysintheAnalogyPartII。chap。viii。，``arepreceptsthereasonofwhichwesee’’。MydifferenceonlybeginswhenIaskmyself，`Whatamongthepreceptsofourcommonconsciencedowereallyseetobeultimatelyreasonable’aquestionwhichButlerdoesnotseemtohaveseriouslyput，andtowhich，atanyrate，hehasgivennosatisfactoryanswer。TheanswerthatIfoundtoitsuppliedtherationalbasisthatIhadlongperceivedtobewantingtotheUtilitarianismofBentham，regardedasanethicaldoctrine:andthusenabledmetotranscendthecommonlyreceivedantithesisbetweenIntuitionistsandUtilitarians。
　　InthisthirdeditionIhaveagainmadeextensivealterations，andintroducedaconsiderableamountofnewmatter。Someofthesechangesandadditionsareduetomodificationsofmyownethicalorpsychologicalviews；butIdonotthinkthatanyoftheseareofgreatimportanceinrelationtothemainsubjectofthetreatise。
　　Andbyfarthelargestpartofthenewmatterintroducedhasbeenwritteneither1toremoveobscurities，ambiguities，andminorinconsistenciesintheexpositionofmyviewswhichthecriticismsofothersormyownreflectionhaveenabledmetodiscover；or2totreatasfullyasseemeddesirablecertainpartsoraspectsofthesubjectwhichIhadeitherpassedoveraltogetherordiscussedtooslightlyinmypreviouseditions，andonwhichitnowappearstomeimportanttoexplainmyopinions，eitherforthegreatercompletenessofmytreatise，——accordingtomyownviewofthesubject，——orforitsbetteradaptationtothepresentstateofethicalthoughtinEngland。Themostimportantchangesofthefirstkindhavebeenmadeinchaps。i。andix。ofBooki。，chaps。i——iii。ofBookii。，andchaps。i。，xiii。，andxiv。ofBookiii。:underthesecondheadImaymentionthediscussionsoftherelationofintellecttomoralactioninBooki。chap。iii。，ofvolitioninBooki。chap。v。，ofthecausesofpleasureandpaininBookii。chap。vi。，ofthenotionofvirtueinthemoralityofCommonSenseinBookiii。chap。ii。，andofevolutionalethicsinBookiv。chapiv。chiefly。
　　Imayaddthatalltheimportantalterationsandadditionshavebeenpublishedinaseparateform，fortheuseofpurchasersofmysecondedition。