 In spite of textual errors and incompleteness, there is no dearth of material in Mohist texts that is highly suggestive of these similarities. In developing their views on disputation from its logical roots, the Mohists appear to have made conscientious and regular use of logical operators that are commonly found in today’s propositional calculi, including conjunction (yu), disjunction (ruo), a variety of articles and verbs for negation (e.g., wu, fei, bu), and implication (variously indicated with ze, ran hou, and other devices). They gave special attention to quantificational notions, taking “no” or “none” (mo) as a primitive (or undefined) notion and in A43 defining “all” (jin) in terms of it: “All is none not being so” or, in modern notation, \(\forall x\varphi\ =_{\mathit{df}}\ \mathrm{N}x\mathord{\sim}\varphi\). Furthermore, in their Greater Selection (Da Qu), they use “all” to define “some”: “Some is not all” (NO5), quite possibly with the definition \(\exists x\varphi\ =_{\mathit{df}}\ \mathord{\sim}\forall x\mathord{\sim}\varphi \) in mind (although textual incompleteness warrants caution on this point; Robins 2010 translates it as “Some is not exhaustive”). They employed special terms for modality, using bi (necessity), for example, as an adverbial relation between two things, where one can be said to be the necessary complement of another (e.g., elder brother and younger brother). And some scholars have suggested that the Mohists took steps toward formalizing their logical views by conscientiously employing variables and other devices that are capable of functioning in the same grammatical role, such as indefinite and demonstrative pronouns (e.g., Liu and Zhang 2010). These views are plausible, but support for them is hampered by the fact that the texts do not present them in an organized fashion, but mention them variously in passing as other views more central to their theoretical program are developed.