Logic and social interaction: introduction

There is now a growing body of research on formal algorithmic models of social procedures and interactions between rational agents. These models attempt to identify logical elements within our day-to-day social activities. Largely using the language of logic and game theory, these studies have led to new insights into the dynamics of observation, updating of knowledge and belief, preference change, dialogues and processes of strategic interaction. Central to many of these studies is a multi-agent perspective on rational agency that situates inference in an interactive context. Logical studies of the role of communication, information exchange and even information hiding are broadening the scope of research on social interaction. This special issue of Knowledge, Rationality and Action centres on the relation between epistemic attitudes and multi-agent interaction. We have five papers that explore different aspects of this relationship: how awareness determines knowledge and ignorance, how communications can ensure some agents’ ignorance while increasing other agents’ knowledge, what merging beliefs may mean in strategic terms, and what may be the linguistic desiderata for epistemic communication protocols. They typically employ models based on dynamic and temporal epistemic logics to study these questions. In all of them, one central issue contributes to complexity: intersubjectivity, whereby agents’ reasoning about each others’ awareness, knowledge and belief, is essential to the design and analysis of their interactions. Agents’ knowledge may in general be limited in many ways. One important way is by which they access such knowledge: agents observe events in the external world, interact with other agents whereby they learn, and perform inferences. Access to knowledge may then be limited in some way by each of these mechanisms which determine what the agent is aware of. The paper by van Benthem and Velázquez-Quesada studies awareness by splitting all information as those that come from external observations (and communication) and those obtained by inference. The dynamics of inference then becomes the focus of their study. The paper by Hoshi and Pacuit studies awareness and access by way of structural limitations which delimit what each agent is in-