羅整菴是明代程朱學派的重要代表，卻以「理氣為一」 之說著稱，近幾十年更為中國大陸學界盛推為「唯物主義」。本文目的在分析整菴理氣論的內涵，以求得正確的定位。 　　筆者以為整菴的理氣論有過渡的、折衷的性格，他一方面承認氣的決定性格，一方面又堅持理的恆定與無所不在，結果造成「理氣渾一、理一分殊」的學說，同時兼顧理與氣的重要性。 　　為了弄清整菴理氣論的形態，筆者又取明道、伊川、朱子的理氣論做比較。筆者以為整菴理氣論乃將朱子的二元論轉回明道伊川的一元論；而在一元論中，他一方面沿襲明道善惡皆天理之說，一方面又像伊川般以理為靜定而無所不在的規範。因此其理論是折衷形態的。

　　　　　This article is a study of Lo Ch'in-shun's doctrine of Principle and Material Force. Its main purpose is to clarify its ambiguity and to give it a proper place in the history of Chinese philosophy. 　　In the history of Chinese philosophy Lo has been interpreted in different and even contradictory ways. He was acknowledged as a representative of the Chu Hsi school, but he held a monistic view of Principle and Material Force, which is different from Chu's dualistic view. In recent decades scholars of Mainland China even praised him as a materialist. My article points out that his doctrine is characterized by eclecticism. On the one hand, he admitted the determinative nature of Material Force; on the other, he insisted the eternity and universality of Principle. As a result, he proposed the doctrine of "oneness of principle and differentiation of particulars," which indicates that these two elements go side by side and are equally important. 　　The author then compares Lo's doctrine with those of Ch'eng Hao, Ch'eng I, and Chu Hsi. Lo's doctrine is a return from the dualism of Chu Hsi to the monism of the Ch'eng brothers. As a monist, Lo accepted Ch'eng Hao's doctrine that both good and evil are Heavenly Principle, while he is similar to Ch'eng I in thinking that Principle is unmoved, omnipresent law of the world. From these characteristics it seems proper to call his doctrine eclecticism.