本文的目的，主要是借用「理性重建」與「典範轉移」這一對概念來分析儒學發展的傳承與轉折。本文作者認為：孔學發展為孟學（或荀學），乃是一種理性重建的工作。新理論的主要工作，乃是引申舊理論的某些關鍵概念而予以重新釐定，並迎接新問題之挑戰而在這些概念的基礎上作理論的提鍊。孔子「仁」一概念的心性論化便是孟子的一大傑作。至於宋明理學與心學之出現，則可說是對先秦儒學的一個革命性的轉變。表面上後來者雖聲稱可「調適而上遂」，可得「先秦之真緒」，實質上乃是另立典範，血脈早已間斷而難通。此即涵有「不可通約」的問題出現。此中原因，實在於道德心性論與本體宇宙論的隔隔不入，難以牽合之故。如果說孟學是孔學的一大傳承，則宋明儒學可說是先秦（孔孟）儒學的一大轉折。

　　　　　This paper mainly aims at using the concepts of 'Rational Reconstruction' and 'Paradigm Shift' to analyse the developmental succession and deviation of Confucianism. On the one hand, the author thinks that the theoretical development from Confucius to Mencius (or Hsun Tzu) is a rational reconstruction. As a rational reconstruction, some key concepts in an old theory will be developed and redefined in a new theory in a new way. In order to face some challenge from a new situation, the new theory has to develop the mentalistic interpretation of Confucius' concept of 'Ren' is a good example of this kind of rational reconstruction. On the other hand, the author claims that the development from Pre-Chin Confucianism to Sung-Ming Confucianism is a revolutionary change. Although the Sung-Ming Confucianists claim fro their status as trus successors of Confucius and Mencius, they do in relaity establish a new paradigm and there is a real problem of 'Incommensurability' between the old theory and their new theories. The main reason is that there is a big gap between moral psychology and ontological cosmology, it is very difficult to combine them into one thing. The conclusion of this paper is that Mencius' theory can be considered as a rational development of Confucius' ideas, but there is a radical change from Pre-Chin Confucianism to Sung-Ming Confucianism.