FBDM is an interdisciplinary working group at the University of Michigan, Ann Arbor. We meet regularly throughout the semester to discuss work by faculty, graduate students, or visitors working on models of belief or decision making, broadly construed. Our members come from a number of disciplines, including philosophy, economics, political science, statistics, computer science, and others. All events are free and open to the public. See the schedule for upcoming talks. If you'd like to get on our mailing list or give a talk at an upcoming meeting see the contact page for more details.
Abstract: Greaves and Wallace (2007) have provided an argument for the belief-revision norm conditionalization which goes roughly as follows: if you stand to learn that one of a partition of propositions is true, and you wish to adopt an actionable strategy for revising your degrees of belief in response to evidence which maximizes the expected accuracy of your posterior degrees of belief, you could do no better than to plan to update by conditionalization. Leitgeb and Pettigrew (2010) have offered an importantly different argument for conditionalization, which goes roughly as follows: upon receiving the evidence E, if you wish to maximize the accuracy of your posterior degrees of belief amongst those possibilities compatible with your new evidence, then you could do no better than to update by conditionalization.
Greaves and Wallace therefore presuppose the norm that you should maximize the expected accuracy of your update strategy, while Leitgeb and Pettigrew presuppose the norm that you should maximize the expected accuracy of your posterior degrees of belief. While these two norms agree when your potential evidence forms a partition, they disagree when your potential evidence fails to form a partition. In the talk, I will argue that, in those cases, we have reason to follow the norm of Leitgeb and Pettigrew; and I draw out some consequences of this position for some other debates in epistemology.
In July 8-10th, 2016, FBDM will host the 9th annual workshop on Decisions, Games, and Logic (DGL2016). More information coming soon!