Logics of Action, Ability, Knowledge and Obligation

ESSLLI 2019
Course Information
  • Lectures: Eric Pacuit (website) and John F. Horty (website)
  • Venue: University of Latvia, Riga, Latvia
  • Dates: August 5 - 10, 2019
  • Meeting Times: 14:00 - 15:30

  • Thinking about rational agents interacting over time is at the center of many research communities represented at ESSLLI. This course will introduce logics for reasoning about individual and group actions and abilities, individual and group knowledge, and individual and group obligations. The course is aimed at students interested in theories of interaction and rational agency, either from a philosophical or from more applied point of view (e.g. multi-agent systems). It will be self-contained, thus does not require previous knowledge of the logical systems we will cover. The primary objective is to introduce students to the active research community centered around the use of logical methods to study rational agency and social interaction.


    The course will focus on the family of stit ("seeing to it that") logics and recent work extending these logical systems. Stit logics---originating with a series of papers by Belnap, Perloff, and Xu---supplements branching time models with an operator representing the agency of an individual in seeing to it, or bringing it about, that some state of affairs holds. Over the past 15 years, there has been a lot of work extending the basic stit logical framework, developing alternative semantics for the basic stit logical language, and comparing and contrasting stit logic with other logics of rational agency (e.g., coaltional logic and alternating time temporal logic). This course will summarize this research highlighting the main conceptual and technical issues.


    In addition to presenting the different logical frameworks and important technical results, we will spend plenty of time motivating the formal machinery. A guiding question for this course is: How does a logical analysis contribute to the broader discussion of rational agency and social interaction within philosophy and the social sciences? The course will be of interest for students in logic, philosophy, computer science (especially multi-agent systems), and linguistics (especially those interested in formal semantics).

Day 1    Introduction to stit logic (with obligations)
Day 2    Stit logic, logics of ability, logics of knowledge
Day 3    Epistemic stit
Day 4    Epistemic stit with obligations
Day 5    More on epistemic stit with obligations, game-theoretic issues