本文從幾個不同的角度，思考張載有關變化氣質的說法。先從「惡之來源」探討張載認為氣質需要變化的原因，張載認為氣質有美惡而無善惡，落在作用上才會產生善惡之惡。作用既受氣質的限制，但也會影響氣質。而個體必然會有所作用，因此必須為善去惡，以突破氣質的限制，並轉化個體的氣質。其次，從「個體化」討論張載對於變化氣質目的之思考。張載認為個體一方面是由氣聚而成質，一方面則是因心的對象化能力而開顯出世界之萬殊。個體的氣質與世界之萬殊雖然是一種限制，但個體的意義正在於藉由突破此種限制以體現天道，因此張載的個體兼有「限制因素」與「表現因素」。最後，本文從張載變化氣質的「下手工夫」進行討論。張載認為氣質雖可變化但無下手處，故下手工夫落在性的兩個開顯處，也就是心與情，相應的工夫是「虛心」與「得禮」。個體一方面藉由禮樂的修養，使情得以抒發但又不至太過，這種平和的情會影響與其相連的氣，使氣質也得到修養。另一方面，藉由心的互換主體能力以進行「虛心」工夫，個體遂可以體物並盡物之性，其心也隨之擴大，而由於張載的心有著氣的向度，故氣質也會隨之充塞而得到變化。至於變化氣質的結果，張載認為隨著個體的心擴充而成大心，身體也擴充而成大體，此時會有萬物一體之感。結論中則藉由與孟子的對照，指出張載的變化氣質工夫是一種「擴充式的工夫論」。

This article examines Zhang Zai’s 張載 doctrine of transformation of one’s internal disposition from different angles. Firstly, by considering the problem of the origin of evil, it explores why Zhang believed that one’s internal disposition must be transformed. Zhang believed that evil is not a part of one’s internal disposition but is produced by one’s behavior. Behavior is constrained by this disposition, yet also influences it. Since behavior is an inevitable part of being human, it is therefore necessary to do good and reject evil in order to overcome the limitations of one’s internal disposition and transform oneself. Secondly, this article aims to raise a few questions relating to the topic of individuation. Zhang believed that humans are on one hand an agglomeration of qi 氣, while on the other the human mind’s ability to objectify the surrounding world makes the world appear to be full of a variety of individuated objects. These aspects are both limitations, and the meaning of being human is to embody the tao 道 by breaking through such barriers; thus to Zhang Zai, individuals have both a “limiting element” and an “expressive element.” Finally, this paper discusses “the starting point for personal cultivation.” Zhang Zai believed that the specific way to transform one’s internal disposition is to empty one’s mind and follow correct etiquette at all times. By means of these internal and external practices, each individual can therefore eliminate the influence of personal desires as well as old habits, and return one’s disposition to its initial state.