Ti (simplified Chinese: 体; traditional Chinese: 體; pinyin: tǐ; Wade–Giles: t'i) is the Chinese word for substance or body.[1] The philosopher Zhang Zai described the ti as "that which is never absent, that is, through all transformations."[1]
In Neo-Confucianism, this concept is often associated with yong, which means "use" or "function." Such function or how the yong of a thing is its activity or its response when stimulated underscores the link.[1] Like the concepts of nei-wai (inner-outer) and ben-mo (root-branch), ti-yong is central to Chinese metaphysics.[2] The link was adopted in order to manifest the actual meaning of the two truths and the relationship between them.[3]