It’s nice when a few people’s interests happen to converge. You start tackling problems together, and learning as a group. This is what happened KMi recently with the Epistemic Logic interest group. We’ve decided to start a seminar, trying to make sense of the ‘epistemic logic‘ area and possibly draw some useful tips from it.

The seminar’s title is “reasoning about knowledge‘. Fagin and others, lead authors in the area, define its scope as follows (get the PDF here):

As its title suggests, this book investigates reasoning about knowledge, in particular, reasoning about the knowledge of agents who reason about the world and each other’s knowledge. This is the type of reasoning one often sees in puzzles or Sherlock Holmes mysteries, where we might have reasoning such as this:
If Alice knew that Bob knew that Charlie was wearing a red shirt, then Alice would have known that Bob would have known that Charlie couldn’t have been in the pantry at midnight. But Alice didn’t know this . . .
As we shall see, this type of reasoning is also important in a surprising number of other contexts. Researchers in a wide variety of disciplines, from philosophy to economics to cryptography, have all found that issues involving agents reasoning about other agents’ knowledge are of great relevance to them. We attempt to provide here a framework for understanding and analyzing reasoning about knowledge that is intuitive, mathematically well founded, useful in practice, and widely applicable.

For the moment we’ve just been clarifying our language and the conceptual tools we need to move on to the core issues. But the discussion’s been really lively, so I guess I’ll keep posting about this. A simple map of the recent meeting is online for public consumption :-)