在理學思想史上，宋儒張載的氣論無疑是在程朱理學與象山心學之外，另一項廣泛影響明清哲學家的思想源頭。設若吾人用以探究哲學家思想全貌的依據，正在於其代表著作，而《正蒙》實為橫渠氣論之代表，則忽略明清《正蒙》各注解本對橫渠氣論的詮釋，豈非意味吾人正採取了一種割裂且零碎的方式，理解明清氣學的動態發展？基於此，本文以「太虛」這項橫渠氣論中最為關鍵的概念，作為研究聚焦的中心。探究明清學者以濂溪之「太極」詮釋張子之「太虛」是否合宜？又由於在明清《正蒙》諸注中，李光地不僅是首先將「太虛是否等同於太極？」顯題化的詮釋者，而且《注解正蒙》更是清代《正蒙》諸注中的官學代表。因此，本文以李光地的詮釋為論述主軸，全文共分三項環節展開討論：首先，本文以「太虛即氣」這項論題，指出李《注》中的虛氣關係。其次，本文通過釐清「太極」、「太虛」與「氣」在李《注》中的關係，指出李光地嘗試調和程朱理學與張載氣論的詮釋進路。最後，李《注》有進於前賢之注解者，在於他明確辨析「太虛」與「太極」之異。但也由於在李《注》所設想的氣論架構中，太極是形而上的理體，太虛與陰陽二氣皆屬氣化層。所以，在詮解《正蒙》的形上思想時，他會批判橫渠見道體未明，陷入「三角底太極」的困境。然而，此項批判是否確當？本文以為，吾人正可依此檢視，在明清《正蒙》思想詮釋史上，《注解正蒙》的洞見與侷限。

Among numerous authors who compose commentaries on Zhengmeng during the Ming and Qing Dynasties, Li Guangdi was the first scholar to consider whether the Great Void (Taixu) equals the Great Ultimate (Taiji). Of the numerous commentaries on the Zhengmeng, Li's Commentary on the Zhengmeng represented the state school of the Qing dynasty. Focusing on the interpretation provided by Li, this study comprised three sections. First, according to the concept that the great void equals qi, we determined the relationship between the Void and qi in Li's Commentary on the Zhengmeng. Second, we clarified the relationship among the Great Ultimate, the Great Void, and qi in Li's commentary, demonstrating that in his interpretation, Li attempted to harmonize the Cheng-Zhu school and Zhang Zai's theory of qi. Third, in the structure of the theory of qi proposed in Li's Commentary on the Zhengmeng, the Great Ultimate was a metaphysical substance, whereas the Great Void and yin–yang belonged to the functional activities of qi. Thus, Li had to jointly adjust the relative positions of other crucial concepts. Based on the first sentence of the first chapter of the Zhengmeng,＂The Great Harmony (Taihe) is called the Way (Tao),＂ we explored how Li posited concepts such as the Great Harmony, the Way, and divine transformation in the theory of qi expounded upon in the Zhengmeng. Lastly, we emphasized the insights provided by and limitations of the Commentary on the Zhengmeng in relation to the history of philosophical interpretation of the Zhengmeng during the Ming and Qing Dynasties and according to the reflective perspective presented in the Original Meaning of the Zhengmeng by Wang Zhi, a Confucian scholar who lived during the Qing Dynasty.