How Do Beliefs Simplify Reasoning?

Abstract

Chapter 9 examines how the proposed theory of epistemic rationality can accommodate outright beliefs, and what role such outright beliefs play in our epistemic conduct. It is argued that people need outright beliefs in addition to credences to simplify their reasoning. Outright beliefs do this by allowing thinkers to ignore small error probabilities. What is outright believed can change between contexts. When our beliefs change, we have to ask how related other beliefs, including beliefs representing uncertainties, change in light of this. It has been claimed that our beliefs change via an updating procedure resembling conditionalization. However, conditionalization is notoriously complicated. This claim is thus in tension with the explanation that the function of beliefs is to simplify our reasoning. We can resolve this puzzle by endorsing a different hypothesis about how beliefs change across contexts that better accounts for the simplifying role of beliefs.