Logic and intelligent interaction

You can think about planet Earth and its natural place for centuries, but to see how it reallymoves, you need to know the solar system, and all the bodies that interact with it. The basic laws of gravity are about ‘social’ push and pull. And what is true of physical bodies, is even more true of our human world, where bodies also have minds. You can think about human beings as isolated information processors as much as you want, turning them into idealized mathematicians serving a life sentence in Platonic Heaven, but if you want to understand the dynamics that gives human actions sense, you need to understand our information about and responses to others. And indeed, there is a fast-growing interest in dynamic logics that deal with ‘intelligent interaction’ (the happy title of a current EC strategic research program1) in communities of rational, or perhaps not so rational agents. There is also a fast-growing jungle of formal systems, sometimes with a ‘religious’ following as so often is the case in early stages of a field. TheWorkshop that led to the present volumewas held at the 2008EuropeanSummer School of Logic, Language and Information (ESSLLI) in Hamburg, August 11–15.2