Belief re-revision in chivalry case

Abstract

We propose a formalization of legal judgment revision in terms of dynamic epistemic logic, with two dynamic operators; commitment and permission. Each of these operations changes the accessibility to possible worlds, restricting to personal belief as local announcement. The commitment operator removes some accessible links for an agent to come to believe an announced proposition, while the permission operator restores them to tolerate former belief state. In order to demonstrate our formalization, we analyze judge’s belief change in Chivalry Case in which a self-defense causes a misconception. Furthermore, we show an implementation of our logical formalization to demonstrate that it can be used in a practical way.