相較於「心」、「性」、「理」、「氣」等宋明理學核心義理言，「情」不是個首出的概念，但論及道德實踐時，它卻是一個重要的概念。因而，理學家如何對「情」進行哲學的思考，是個有意義的提問。尤其，在晚明崇尚情欲之風下，作爲理學殿軍的劉蕺山（宗周，1578-1645），他如何論述「情」，更是個值得關注的問題。而蕺山對《中庸》「喜怒哀樂」所作的創造性詮釋，最能彰顯其論「情」的原創性。本文首先透過宋明理學「性情論」的考察，指出蕺山以「性之情」理解《中庸》「喜怒哀樂」之「情」，有宋明理學義理發展的必然性。其次，由蕺山對朱子性情論的批判，拆解朱熹以來「性情」對舉二分的主流看法，強調「情」作「情實」解的古義。並以「即性言情」的進路，界定「喜怒哀樂」爲「性之情」，名之爲「四氣」或「四德」；進而「指情言性」，以「喜怒哀樂」之周流不息。（貞下起元、哀樂相生），來具體化天道性體心體之義蘊。如是，「喜怒哀樂」乃脫離一般作爲感性之情的日常語言之含義，成爲一本體宇宙論之哲學概念。最後，再由「喜怒哀樂」與「七情」之區分，思考蕺山論「情」所蘊涵的哲學洞見，及其對晚明思想界的回應。

Although the concept of qing may not be as dynamic and nuanced as those of xin, xing, li and qi in the core of Song-Ming Neo-Confucianism, qing is fundamental when moral cultivation is concerned. Arguably the last significant Neo-Confucian thinker, Liu Jishan (1578-1645) offered a philosophical treatise on qing amidst the late Ming's obsession with the ideas of qing (sentiment) and yu (desire). Liu's insight was fully borne out in his creative interpretation of the meaning of "pleasure, anger, sorrow, and joy" from the Zhongyong. This paper begins with a survey of the philosophical treatments of xing and qing in Song-Ming Neo-Confucianism and points out that Liu's understanding of the qing embedded in "pleasure, anger, sorrow, and joy" as stemming from xing, human nature, is in keeping with this tradition. It then examines Liu's critique of Zhu Xi's influential dichotomy of xing and qing; Liu's was an effort to restore qing as the essence of human nature. Fusing qing to xing is in effect providing a legitimate dwelling place for qing, understood now as an element of human nature embodied in "pleasure, anger, sorrow, and joy," which Liu called the siqi (four kinds of qi) or side (the four virtues). After securing the qing-as-xing logic, Liu pondered its onto-cosmological implications. He observed how tiandao (way of heaven), xingti (the matter of nature), and xinti (the matter of the mind) are manifested through the ceaseless activity of the "four kinds of qi," and showed that the "pleasure, anger, sorrow, and joy" of a human being are the original moral agents in the mind. At this point, the phrase "pleasure, anger, sorrow, and joy" departs from its customary meaning and acquires an ontocosmological significance. This paper also considers the distinction between "pleasure, anger, sorrow, and joy" and qiqing (the seven kinds of emotions) that Liu made to further show his insight on the concept of qing and his reaction to other late-Ming thinkers.