宋明理學的研究問題中，分系問題無疑是十分重要的課題。因為對宋明理學分系 之研究，不但能掌握宋明理學之內容與發展，同時也能藉此理解其所以分系背景，進而由此 對比出不同的中國哲學史觀。 本文的主要目標，在試圖通過勞思光先生對宋明理學分系的討論，掌握其分系的理論根 據及其內容，並進一步對比著牟宗三先生之分系，比較其間的利弊得失。筆者以為，勞先生 以一系三階段說，在傳統的二系說及牟先生的三系說之間，取得非常特殊的結論，這不但顯 示勞先生對宋明理學的特殊理解，也說明了勞先生利用心性論與宇宙論的對比，所理解出的 中國哲學之特質。

　　　　　Genealogy stands at a critical point in the study of Sung-ming-li-hsueh. Various kinds of genealogy let us discover the differences between schools; in addition, each genealogical approach implies its particular theoretical system of understanding. In other words, genealogical approach displays how a scholar understands Sung-ming-li-hsueh, and how he understands the whole of Chinese philosophy as well. This paper aims to analyze Lau Ssu-Kung's monistic genealogy of Sung-ming-li-hsueh. With this analysis of his monistic viewpoint, we can distill his theoretical background toward the whole of Confucian philosophy; moreover, we can make a fair judgment about his system of understanding. Ssu-kung displaces Mou Tsung-san's triangular genealogy and the traditional dualistic one. Lau Ssu- Kung locates Confucianism in the context of human nature and mind, and thus he excludes the dimension of metaphysics. This is just where he shows his insights, but where he might thus show restraint.