本文「朱子的『心中之理』之研究」，欲對朱子的心與理的關係作新的定位，以證成朱子可有本具、本知道德法則的意思。本文能達至以下三點結論：第一、朱子雖非陸、王「心即理」的型態，然其思想中的心卻不可僅以認知心、心理學式的心視之，必須以著「理氣合」、「心理合一」來理解朱子的心，可說是介於「心即理」與牟先生的「心具理」之中間的一種理解，這亦很可能是朱子的原意。第二、朱子的格物型態並不能以一般所理解的認知、認識視之，朱子格物就是在使吾人本有的良心作用能完全彰顯。當然，這並非「逆覺體證」，格物就是在使吾心本知的理彰明、擴充出來。第三、朱子心中的性理是有「理在氣中發」的意涵，這就是朱子的道德動力之所在。此性理之發雖非心能自發道德之理，但此性理時時可作用、警策、引導吾心去做道德實踐。

The Study of Zhu Xi's ＂Principle in mind＂--would reconfirm Zhu Xi's theory of the relationship between Mind and Principle. In this paper, we would comprehend that Zhu Xi is ＂Principle in Mind＂ and the mind would know ＂Moral laws＂ originally. We want to obtain three conclusions. First, Zhu Xi's thought could not be regarded as ＂Principle is mind＂. However, his Mind is not only cognitive or psychological mind. So we must comprehend that Zhu Xi's ＂Principle and Material Force （氣） are one＂ and ＂Principle and Mind are one＂.Consequently, Zhu Xi's ＂Principle in mind＂ would be between Lu Shiangshan and Wang Yangming's ＂Principle is mind＂ and Mou Zongsan's ＂Principle connect with Mind＂ （心具理）. This opinion might be Zhu Xi's real intention. Secondly, Zhu Xi's investigation（格物）is not only a function of cognition. Its intention would be signifying human's function of conscience. This is not ＂retrospective recognition＂（逆覺體證）. But his investigation certainly could reveal principle is in mind originally. Finally, Zhu Xi's ＂principle in mind＂ is the same as ＂principle moves in material force＂. So we can say Zhu Xi's Ethics its moral dynamics. Originally, Zhu Xi's principle could not stimulate moral dynamics. But in this paper, we could confirm his principle really can guide people’s mind to practice moral behaviors.