孔子是儒家開山祖師，也是中國哲學史上第一位哲學家，同時是中華文化中影響最深遠之聖賢，他對「本性論」如何理解，值得加以探究。古代哲人本性論依發展階段可分兩型：「前理論期」與「理論成型期」；後者指哲人對本性論之論述已相當完足，故要研究此等哲人之本性論，只要將該哲人有關本性之論述作分析歸納便得；前者則哲人尚無充足完整之概念陳述與理論架構，故若要研究此等哲人之本性論，無法取給於哲人對本性之相關論述，故得另覓新法。孔子的本性論屬「前理論期」，蓋《論語》中論「性」文字僅兩見，實無法單憑分析歸納此有限資料以知孔子本性論內涵；故本文提出「前理論期研究法」以為探索孔子本性論之方法論，此法將探索範疇延伸至未用本性概念描述的本性思想中，藉由對此等資料之蒐羅考論，期能得出孔子本性論之完整意蘊，斯本文之旨。

Confucius is the founder of the Confucian School, the first philosopher in the Chinese history of philosophy, and the most influential saint in the Chinese culture. His Theory of Human Nature is worthy of further analyses and discussions. The theories of human nature from ancient philosophers can be divided into 2 types according to their development periods: The "pre-theory period" and "theory forming period". The latter is referred to the period during which the philosophers have a complete theory of human nature; therefore, researching into such type of theories is to analyze works relevant to certain philosophers' theory of human nature. However, philosophers do not have complete concepts or theory constructions during the "pre-theory period"; as a result, new research methods are required when doing researches on such type of theory of human nature since there are no relevant works. Confucius's Theory of Human Nature belongs to the "pre-theory period". It is not possible to have a complete understanding of this theory through analyzing the limited parts about "human nature" in The Analects of Confucius; therefore, this paper aims to discuss the Methodology in the Theory of Human Nature based on "Pre-theory Period Research Method". It covers human thinking which has not been described through human nature concepts, and hopes to have a complete understanding of the meaning of Confucius's Theory of Human Nature through collecting and analyzing relevant documents.