 Inference is commonly understood as a syntactic operation on the form of a sentence or assertion that preserves the semantic property of truth. Aristotle’s logic, in which validity is determined by an argument’s categorical form independently of the truth of its premises and the semantics of its terms, is an example. Like most other early Chinese philosophers, the Mohists do not appear to have conceived of valid inference in this way. Even as they gave increasing attention to matters of logical or grammatical form, they remained skeptical that different categories of form can be regarded as an invariable guide to meaning. In particular, they were consistently wary of assuming that the meaning of a sentence or complex is determined by the meanings of its constituent parts and their modes of combination. For this reason they maintained that valid inference is partly a semantic affair, hinging on our consideration of the idiosyncrasies of meanings in combination. So rather than developing a theory of inference strictly on the basis of appeals to logical or linguistic form, they instead sought to develop a viable classification of what they took to be valid inference patterns based on analogies in the semantics of terms in combination (see  section 3.4  below).