摘要:Normal 0 21 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} In this paper, we seek to analyze some aetiological principles of Thucydides' historical narrative, focusing our attention on the emphasis assigned by the chronicler to impulses that constitute human nature ( anthrópeia physis ), the truest cause of the war among Athenians and Spartans. The paper also examines (1) Thucydides' portrayal of the relationship between the impulsive ( orgé ) and the reflective ( gnómé ) sides of human nature and (2) their consequences in the resolution of human destiny. Key words: Thucydides, human nature, Greek historiography.