This week, we're going to be discoursing about common knowledge and Aumann's agreement theorem. The meetup will be in a partial partitioned book club format. The goal is to read and discusss a CIFAR lecture on the topic, and two papers by Lederman on the topic. The papers have several independent sections, so we'll read those in a partitioned format.

Readings

1. Read this blog post by Scott Aaronson (which is a transcript of a lecture)
2. Read sections 1 and 2 of this 2014 paper by Lederman
3. Read section 1 of this 2017 paper by Lederman
4. Pick one of sections 3, 4, 5, 6 from Lederman2014 or sections 3, 4 from Lederman2017 to read in this spreadsheet. The sections are not all of the same length, sorry.

Discussion

We'll do a combination of general discussion and each person presenting their section. Some discussion suggestions:

1. Before reading any of this, what was your intuitive reaction to "rational agents can't agree to disagree"? What is your intuitive reaction after the readings?
2. Do you think Aaronson's result about the communication complexity of agreement makes Aumann agreement more practically relevant?
3. Of the four hidden assumptions considered by Lederman, which one is the most defensible idealization of humans? What about the considerations in his sailboat argument?
4. Does Aaronson's result about communication complexity survive if we drop any of the four assumptions?
5. Does Aaronson's result dodge the objection about common knowledge never being obtained in the sailboat argument?
6. If you buy Lederman's argument about common knowledge never being obtained, does that let you off the hook for updating on disagreement? Or does some weaker prescription survive?