Doxastic Logic, Probability and Default Logic

Course Information
  • Lectures: Eric Pacuit (website) and Aleks Knoks (website)
  • Venue: University of Ljubljana, Solvenia


  • Dates: July 31 - August 4, 2023
  • Meeting Times: 2:00pm - 3:30pm
  • Logicians, philosophers, and artificial intelligence researchers interested in epistemic questions---or, roughly, questions relating to belief, knowledge, and reasoning---have developed formal models to refine these questions and to answer them. This course will introduce three of the most prominent such formal models: doxastic logic, Bayesian models, and default logic. We will introduce these models, highlighting their similarities and differences, as well as their advantages and pitfalls. The course will touch on the fundamental questions driving much of the research in formal epistemology. In addition to presenting the different models, we will discuss such issues as the lottery and preface paradoxes, doxastic paradoxes, the source of epistemic normativity, and puzzles associated with higher-order evidence and peer disagreement. Topics that will be discussed include:

    • Modal logics of belief (with propositional quantifiers)
    • Bayesian epistemology, accuracy arguments for probabilism
    • The Buridan-Burge Paradox
    • Lottery and Preface Paradox
    • Reflection Principles
    • Default logic
    • Applications of default logic in the context of the peer disagreement debate; debates about the nature of (epistemic) authority, expertise, and deference

Day 1    Doxastic Logic
Day 2    Probability I
Day 3    Probability II and Introduction to Default Logic
Day 4    Default logic I
  • Slides

  • Note that there is a problem set at the end of the slides.

Day 5    Default logic II