Asthedifferentrulesofmoralityadmitsuchdifferentdegreesofaccuracy，thoseauthorswhohaveendeavouredtocollectanddigestthemintosystemshavedoneitintwoDifferentmanners；andonesethasfollowedthroughthewholethatloosemethodtowhichtheywerenaturallydirectedbytheconsiderationofonespeciesofvirtues；whileanotherhasasuniversallyendeavouredtointroduceintotheirpreceptsthatsortofaccuracyofwhichonlysomeofthemaresusceptible。Thefirsthavewrotelikecritics，thesecondlikegrammarians。
I。Thefirst，amongwhomwemaycountalltheancientmoralists，havecontentedthemselveswithdescribinginageneralmannerthedifferentvicesandvirtues，andwithpointingoutthedeformityandmiseryoftheonedispositionaswellastheproprietyandhappinessoftheother，buthavenotaffectedtolaydownmanypreciserulesthataretoholdgoodunexceptionablyinallparticularcases。Theyhaveonlyendeavouredtoascertain，asfaraslanguageiscapableofascertaining，first，whereinconsiststhesentimentoftheheart，uponwhicheachparticularvirtueisfounded，whatsortofinternalfeelingoremotionitiswhichconstitutestheessenceoffriendship，ofhumanity，ofgenerosity，ofjustice，ofmagnanimity，andofalltheothervirtues，aswellasoftheviceswhichareopposedtothem:and，secondly，whatisthegeneralwayofacting，theordinarytoneandtenorofconducttowhicheachofthosesentimentswoulddirectus，orhowitisthatafriendly，agenerous，abrave，ajust，andahumaneman，would，uponordinaryoccasions，chusetoact。
Tocharacterizethesentimentoftheheart，uponwhicheachparticularvirtueisfounded，thoughitrequiresbothadelicateandanaccuratepencil，isatask，however，whichmaybeexecutedwithsomedegreeofexactness。Itisimpossible，indeed，toexpressallthevariationswhicheachsentimenteitherdoesoroughttoundergo，accordingtoeverypossiblevariationofcircumstances。Theyareendless，andlanguagewantsnamestomarkthemby。Thesentimentoffriendship，forexample，whichwefeelforanoldmanisdifferentfromthatwhichwefeelforayoung:
thatwhichweentertainforanausteremandifferentfromthatwhichwefeelforoneofsofterandgentlermanners:andthatagainfromwhatwefeelforoneofgayvivacityandspirit。Thefriendshipwhichweconceiveforamanisdifferentfromthatwithwhichawomanaffectsus，evenwherethereisnomixtureofanygrosserpassion。Whatauthorcouldenumerateandascertaintheseandalltheotherinfinitevarietieswhichthissentimentiscapableofundergoing？Butstillthegeneralsentimentoffriendshipandfamiliarattachmentwhichiscommontothemall，maybeascertainedwithasufficientdegreeofaccuracy。Thepicturewhichisdrawnofit，thoughitwillalwaysbeinmanyrespectsincomplete，may，however，havesucharesemblanceastomakeusknowtheoriginalwhenwemeetwithit，andevendistinguishitfromothersentimentstowhichithasaconsiderableresemblance，suchasgood-will，respect，esteem，admiration。
Todescribe，inageneralmanner，whatistheordinarywayofactingtowhicheachvirtuewouldpromptus，isstillmoreeasy。