Abstract de la publi numéro 10692

The focus of this contribution is to define speech acts as institutional actions where modeled institutions are social or informal institutions. With social or informal institution, we mean an institution which is grounded on the acceptances of its members. In the first part of the paper we present a logic of acceptance, goal and action. Then, we specify how agents can create and maintain normative and institutional facts on the basis of their acceptances qua members of a certain institution. In particular we focus on obligations and social commitments and provide an original reductionist characterization of these concepts, anchoring them in agents' attitudes. Finally, we propose a formal characterization of the speech act promise. In this last part, we first define the constitutive rule which creates the relation between an utterance (as a physical action) and the speech act promise (as an institutional action). Then, we specify the deontic dimension of promise. Finally, we establish the relationship between promise and social commitment.