Norms, Action and Agency in Multi-agent Systems

Abstract

This presentation has two parts. The technical part concerns the logic of expressions of the form ‘agent x brings it about that A’, or ‘agent x is responsible for its being the case that A’, or more generally, ‘the group of agents G collectively, though perhaps inadvertently, bring it about that A’. I will present an account that combines this agency view of action with the transition based conceptions more usually encountered in computer science and temporal logic. A two-sorted (modal) language is defined for talking about properties of states and transitions in a transition system, and about the actions of individual agents or groups of agents, including two modalities of the ‘brings it about’ kind. Since no assumptions at all are made about the reasoning or perceptual capabilities of the agents—they can be human, or computer agents, or simple reactive devices—I refer to this form of agency as ‘unwitting’; unwitting can mean both inadvertent and unaware. The resulting logic bears a resemblance to Ingmar Pörn’s (1977) logic of ‘brings it about’ though there are differences, The account generalises naturally to talking about the collective actions of groups of agents: several different forms of (unwitting) collective agency can be identified.