Credences

An individual’s credence in a proposition is a measure of the strength of their belief in that proposition; that is, it measures how confident they are in that proposition. Typically, credences are measured on a scale from 0 per cent or 0 (which represents complete disbelief) to 100 per cent or 1 (which represents complete certainty). Credences are used in philosophy to provide a more fine-grained representation of an individual’s doxastic state than we obtain if we merely specify whether they believe the proposition. When we represent individuals using credences, we must say when those doxastic states are rational and when they’re not. These norms govern much scientific theorising, since scientists reason with their credences about different hypotheses and different bodies of evidence to come to conclusions about the world; but they also govern our reasoning in our daily life. We also use credences in our daily lives to guide our actions, and there are norms that govern how we should do that.