AbstractThe Gricean GCI-PCI divide has long been questioned inlinguistic pragmatics. Taking Chinese méimù in the CCL corpusas the case, the present study proposes the cognition-pragmatics diachronicmodel to examine Grice’s GCI-PCI divide. It is found that with the frequency ofrepeated usage increasing over time, PCIs develop into GCIs; these two types ofconversational implicatures are not easily divided. Semantic change from PCIs toGCIs is a dynamic process of cognition from individual entrenchment tocollective conventionalization. By schematization and categorization, the formergradually builds an individual’s knowledge network with many entrenched PCInodes, while the latter is reflected as sharing some parts of the individual’sknowledge network in the collective minds, i.e., the community’s knowledgenetwork with some conventionalized GCI nodes, further forming socio-culturalconventions in a speech community. During this process, there is a division oflabor between context and conventions. Therefore, the diachronic study sheds newlight on the relationship between GCIs and PCIs.