《墨辯》對「侔」的界定是「侔也者，比辭而俱行也」和「辭之侔也，有所至而正」，即「侔」必須既滿足「辭」與「辭」之間的「比」且「行」，又要滿足「辭」符合「正」的要求這樣兩大基本條件。而只有「是而然」這一種情形符合這兩大基本條件，因此「侔」即「是而然」本身。「侔」又可以具體分為三種類型，這也是「侔」的三款基本內容，即「加侔」、「減侔」和「換侔」。通過對墨「侔」三款的基本內容「加侔」、「減侔」和「換侔」的分析，可以對墨「侔」屬西洋形式邏輯之「附性法」、墨「侔」屬「複雜概念推理」或「關係推理」、墨「侔」即「排比」、墨「侔」有「減詞」與「減辭」說等學界觀點進行商榷。

“Parallelism” (Mou) is defined in Mohist Dialectics as such: “comparing (Bi) propositions (Ci) and jointly proceeding (Xing) is called parallelism” and “the parallelism of propositions is valid (Zheng) only to a certain extent.” In other words, if parallelism is tenable, it should meet two basic regulations, i.e. “comparing” and “proceeding”, as well as meeting the requirement of “validity” between propositions. Only the case of “this and so” (Shi Er Ran) is eligible to conform to both basic regulations, so the case of “this and so” is parallelism itself. There are three situations, i.e. three types in parallelism’s basic contents, making parallelism possible, that are the parallelism of amplification (Jia), the parallelism of omission (Jian) and the parallelism of substitution (Huan). Meanwhile, the reason or the standard which makes parallelism possible is the category of “sameness” (Tong). ording to the analysis of the three types in parallelism’s basic contents, we can deliberate on the ideas that Mohist parallelism belongs to the method of adding the adjective to the proposition in Western formal logic, belongs to complicated conceptual inference or relational inference and belongs to parataxis or alignment as well as that it has a pattern of omitting word(s) or proposition(s).