Mild contraction

by Isaac Levi

"Isaac Levi's new book develops further his pioneering work in formal epistemology, focusing on the problem of belief contraction, or how rationally to relinquish old beliefs. Levi offers the most penetrating analysis to date of this key question in epistemology, offering a completely new solution and explaining its relation to his earlier proposals. He mounts an argument in favour of the thesis that contracting a state of belief by giving up specific beliefs is to be evaluated in terms of the value of the information lost by doing so. The rationale aims to be thoroughly decision theoretic. Levi spells out his goals and shows that certain types of recommendations are obtained if one seeks to promote these goals; he also compares his approach to his earlier account of inductive expansion. The recommendations are for 'mild contractions'. These are formally the same as the 'severe withdrawals' considered by Pagnucco and Rott, but the rationale is different. A critical part of the book con