Humannatureisthefundamentalnatureandsubstanceofhumans,aswellastherangeofhumanbehaviorthatisbelievedtobeinvariantoverlongperiodsoftimeandacrossverydifferentculturalcontexts.

　　Inpre-modernandnon-scientificunderstandingsofnature,thismeantthathumannaturemustbeunderstoodwithreferencetofinalandformalcauses.Suchunderstandingsimplytheexistenceofadivineinterestinhumannature,and/ortheexistenceofanideal,"idea",or"form"ofahumanwhichexistsindependentlyofindividualhumans.

　　Accordingtotheacceptedmodernscientificunderstandinghumannatureistherangeofhumanbehaviorthatisbelievedtobenormaland/orinvariantoverlongperiodsoftimeandacrossverydifferentculturalcontexts.

　　Theexistenceofaninvariablehumannatureisasubjectofmuchhistoricaldebate,particularlyinmoderntimes.Mostfamously,Darwin'sgaveawidelyacceptedscientificargumentthathumansandotheranimalspecieshavenotrulyfixednature.Beforehim,themalleabilityofmanhadbeenassertedbyJeanJacquesRousseau.

　　Sincethemid-19thCentury,theconceptofhumannaturehasbeencalledintoquestionbythinkerssuchasHegel,Marx,Nietzsche,Sartre,anumberofstructuralistsandpostmodernists.Theconcepthasalsobeenchallengedbyviewssuchasbehaviorism,determinism,andthechemicalmodelwithinmodernpsychiatryandpsychology,whichhavetendedtoemphasizetheideathathumanbeingsmightconceivablybeexplainedas"matterinmotion"inawaythatissimilartotherestofnature.RecentlythebiologistE.O.Wilsonformulatedascientificdefinition.

　　Thereareanumberofperspectivesregardingthefundamentalnatureandsubstanceofhumans.Thesearebynomeansmutuallyexclusive,andthefollowinglistisbynomeansexhaustive:

　　Philosophicalnaturalism(whichincludesmaterialismandrationalism)encompassesasetofviewsthathumansarepurelynaturalphenomena;sophisticatedbeingsthatevolvedtoourpresentstatethroughnaturalmechanismssuchasevolution.Humanistphilosophersdeterminegoodandevilbyappealtouniversalhumanqualities,butothernaturalistsregardthesetermsasmerelabelsplacedonhowwellindividualbehaviourconformstosocietalexpectations,andistheresultofourpsychologyandsocialization.

　　Abrahamicreligionholdsthatahumanisaspiritualbeingwhichwasdeliberatelycreated(exnihilo)byasingleGodinhisimage,andexistsincontinuedrelationshipwithGod.GoodandevilaredefinedintermsofhowwellhumanbeingsconformtoGod'scharacterorGod'slaw.

　　Polytheisticoranimisticnotionsvary,butgenerallyregardhumanbeingsascitizensinaworldpopulatedbyotherintelligentspiritualormythologicalbeings,suchasgods,demons,ghosts,etc.Inthesecases,humanevilisoftenregardedastheresultofsupernaturalinfluencesormischief(althoughmayhavemanyothercausesaswell).

　　Holistic,pantheistic,andpanentheisticspiritualtraditionsregardhumanityasexistingwithinGodorasapartofDivinecosmos.Inthiscase,human"evil"isusuallyregardedastheresultofignoranceofthisuniversalDivinenature.TraditionsofthiskindincludeVedicreligionsandotherformsofEasternphilosophy(includingBuddhismandTaoism),andWesternphilosophysuchasStoicism,Neoplatonism,orSpinoza'spantheisticcosmology.Certainkindso