1. Introduction his paper discusses the results of a micro-study on the possibility for the verbs know, think and believe to be explicitly opposed in the syntactic pattern “I don’t think/believe so, I know so” and to be considered as antonyms. Despite the fact that hypothetically, in such a context, other verbs of cognitive attitude (eg suppose) might fill the slot occupied by think and believe, as a matter of fact, none seems to occur in this type of opposition. his opens the path for a number of interesting questions relative to the special status of the relationship between know, think and believe within the wider class of English verbs of cognitive attitude (Cappelli 2007b). In what follows, this preference observed in both naturally occurring and elicited data is discussed and explained through suggestions provided by dynamic approaches to meaning construal underlying both the theory of Lexical Complexity (Bertuccelli Papi and Lenci 2007) and the principle of Relation by Contrast–Lexical Contrast (Murphy 2003).