Idealization in Decision Theory: Is Common Knowledge like a Frictionless Plane?

This talk begins with a contrast between how philosophers and economists typically model knowledge. Economists tend to model knowledge introspectively—agents know what they know, and what they don’t know—while (most) philosophers treat this as an occasionally convenient but strictly false idealization, and prefer to explore non-introspective models of knowledge. I examine a common philosophical picture on which introspection and common knowledge are in principle eliminable simplifying assumptions, and ask whether that way of understanding them is ultimately misguided.