 As we saw above, “same” (tong) and “different” (yi) are central concepts in ancient Chinese theories of language, knowledge, and disputation, as represented by the Mohists and Xunzi. According to the Mohists, “sameness” can refer to at least four types of relations: identity; part-whole relations; being grouped together or co-located; and having some intrinsic similarity and thus being part of the same “kind”. This last variety of “sameness” is probably most important for our purposes here. Names names for “kinds” (lei)—one type of general term— are regarded as denoting all things or stuff (shi) that is “the same” in one or more respects, such as all horses, which share the same shape (xing) and appearance (mao). Speakers can use language to communicate because they are familiar with the kinds of similar things that words refer to, and thus upon hearing a word know what the thing referred to “is like.” The relations of “same” and “different” determine what counts as correct matching of names and stuff and thus what knowledge is. Disputation is fundamentally a process of debating whether the thing in question is “this” (shi) or “not-this” (fei), the same as or different from some model, paradigm, or analogy. The issue of how to distinguish “same” from “different” is thus pivotal to Chinese philosophy of language, epistemology, and disputation. 