IneachcaseStatecraftisanArt，andthefinancialpolicyisanartisticorcreativeworkinwhichquantitiesareusedbutdonotdirectordominate。
Bythislineofargumentitmayappearasifwehadrepudiatedtheentireutilityofascientificcalculus。This，however，isnotthecase。
Forthoughallthedeterminantactsofpolicyorwelfare，performedbyanindividualorasociety，involveorganicunityofdesign，andthequalitativeconsiderationsappertainingthereto，importantandindeednecessaryassistanceisrenderedbythequantitativeanalysisofpastactsexpressedintheformofscientificgeneralisations。Aclearerunderstandingofthenatureandextentofthiscooperationbetweenscienceandartintheconductoflifeenforcesthistruth。
§；11。SciencetakesitsstanduponatwofoldapplicationoftheassumptionoftheuniformityofNature，first，thatalldifferencesofcompositioncanbetreatedasdifferencesofquantityordegree，secondly，thathistoryrepeatsitself。Now，justsofarastheseassumptionsfitthefacts，Scienceisvalidforinterpretationandforguidance。Thisexplainswhyastronomy，physicsandchemistryaremore\'exact\'sciencesthanbiologyorpsychology，andwhytheyareabletogivemorereliableandauthoritativerulesfortheartsofnavigation，engineeringanddrug-making，thanthelattercanformedicine，forbreedingorforeducation。EdwardCarpenterhasremarkedthatastronomyisthemostexactoftheappliedsciences，becauseweknowleastaboutit，i。e。，becausewetreatitssubject-matteralmostentirelyfromthesinglequantitativestandpointofspacerelations。
Inallartsdealingentirelyormainlywithinorganicmatterscienceoccupiesaseatofhighauthority，becauseofthehighrelativeuniformityofthismatterandthecomparativeregularityofitsbehaviour。Inphysicsorininorganicchemistrytheindividualdifferencesoreccentricitiesofthematerialaresotrivialthattheycanusuallybedisregarded，andhistoryrepeatsitselfwithsomuchregularitythatquantitativelawsapply。