Thisisthenthesubjectonwhichitismostimportantforeachofustoentertainfixedideas;andunhappilyitisalsothesubjectonwhichitismostdifficultforeachofus，lefttohimself，tosettlehisopinionsbythesoleforceofhisreason。
Nonebutmindssingularlyfreefromtheordinaryanxietiesoflife—mindsatoncepenetrating，subtle，andtrainedbythinking—canevenwiththeassistanceofmuchtimeandcare，soundthedepthofthesemostnecessarytruths。And，indeed，weseethatthesephilosophersarethemselvesalmostalwaysenshroudedinuncertainties;thatateverystepthenaturallightwhichilluminatestheirpathgrowsdimmerandlesssecure;andthat，inspiteofalltheirefforts，theyhaveasyetonlydiscoveredasmallnumberofconflictingnotions，onwhichthemindofmanhasbeentossedaboutforthousandsofyears，withouteitherlayingafirmergraspontruth，orfindingnoveltyeveninitserrors。
Studiesofthisnaturearefarabovetheaveragecapacityofmen;
andevenifthemajorityofmankindwerecapableofsuchpursuits，itisevidentthatleisuretocultivatethemwouldstillbewanting。FixedideasofGodandhumannatureareindispensabletothedailypracticeofmen’slives;butthepracticeoftheirlivespreventsthemfromacquiringsuchideas。
Thedifficultyappearstometobewithoutaparallel。