 Williamson (1996, 239) has argued that that speech acts defined by constitutive rules (like assertion, in his own view) cannot be conventional. However, García-Carpintero (2019) has shown that this position is controversial. The situation is complicated by the fact that the general question of when a convention, or rule of any kind, is in force for a speaker, is substantial and complex (for more on the relation of assertion to convention, Green 2020a).