The paper outlines an approach to the formal representation of signalling conventions, emphasising the prominent role played therein by a particular type of normative modality. It is then argued that, in terms of inferencing related to this modality, a solution can be given to the task J. L. Austin set but failed to resolve: finding a criterion for distinguishing between what Austin called constatives and performatives. The remainder of the paper indicates the importance of the normative modality in understanding a closely related issue: reasoning about trust in communication scenarios; this, in turn, facilitates a clear formal articulation of the role of a Trusted Third Party in trade communication.
Andrew J. I. Jones, Steven O. Kimbrough