王船山詮釋《繫辭傳》「一陰一陽之謂道」一章中，道、善、性三概念的說法，極為奇特，當代學者對之早有論析，並批評其說不妥者。唐君毅先生對船山此一理論所牽涉的問題，有全面的討論與深刻的分析，且具同情的了解，作者曾為文專論唐先生之說的內涵。唯該文非專就船山理論本身做討論；又，因唐先生之論，在某些方面來說，於船山本旨尚有未盡；特別是因，宋明理學所建立之儒家道德的形上學，其理論內部存在著一些問題，而在「道、善、性」的理論中，這些問題是可避免的。本文之作，便是就船山此理論的涵義與價值，做進一步的詳探。

Confucian scholars long held that there were only two graded beings: Tian Ming (heaven’s order) and Xing (nature), between heaven and people, until Wang Chuan-shan, elaborating on what was said in Yijing Xici chuan, postulated the three graded beings of “Dao (heaven), Shan (goodness), and Xing (nature),” among which there was an ontological distinction. To talk about Wang’s theory of “Dao, Sang, Xing,” the contemporary scholars criticized it has no validity and propriety. Tang Junyi had generally discussed and elaborated Wang’s theory of “Dao, Sang, Xing.” In the interpretation of Tang, he could appropriately capture Wang’s spirit. I had made a study of Tang’s interpretation. Because of that there were some aspects in the theoretical implications of “Dao, Sang, Xing,” Tang’s statement was not appropriate; especially owing to that there were many theoretical problems in the moral metaphysics established by the Confucian scholars at Song Dynasty, but they could be avoided in Wang’s theory of “Dao, Sang, Xing,” so that the present writer analyzed the theoretical implications and explained the values of “Dao (heaven), Shan (goodness), Xing (nature).”