Logic of Agency

(EASSS: European Agent Systems Summer School 2018)

Daniele Porello

Nicolas Troquard



The concept of action is an all-around topic of scholarly investigation. The formal aspects have long been studied by philosophers. It is also a fundamental concept in multiagent systems (MAS) whose main objective is the design of artificial agents who have to interact in an environment, by selecting a given course of action on the basis of their beliefs and preferences. This course is to provide a gentle overview to the logics if agency and of their applications, by focusing on logics of agency that abstract away from the process of action and concentrate on the result of the action. It includes Belnap and colleagues Seeing-To-It-That (STIT), and the logics of Bringing-It-About (BIAT) due to Kanger, Pörn, and others. They are modal logics where for each agent i there is a modality DOES_ i where DOES_ i A means that “i sees to it / brings about that A is the case”. These modalities are versatile and can be usefully combined with other notions like time, obligations, beliefs. They find many natural applications in modeling and reasoning about processes, individual agency and collective agency.