The Logic of Belief Change

The logic of belief change is about how we update what we think based on new information. When new facts show our current beliefs are wrong or incomplete, we adjust our beliefs accordingly—this process is called belief revision. Conversely, if we encounter information that confirms what we already think, we strengthen our beliefs—called belief update. The goal is to maintain a coherent set of beliefs that accurately reflects the world, balancing openness to new evidence with consistency. This systematic approach helps us reason effectively and make better decisions as we encounter new information.