This book has grown out of a conference on Degrees of Belief that was held at the University of Konstanz in July 2004, organised by Luc Bovens, Wolfgang Spohn, and the editors. The event was supported by the German Research Fo- dation (DFG), the Philosophy, Probability, and Modeling (PPM) Group, and the CenterforJuniorResearchFellows(since2008:Zukunftskolleg)attheUniversityof Konstanz. The PPM Group itself - of which the editors were members at the time - was sponsored by a So a Kovalevskaja Award by the Alexander von Humboldt Foundation, the Federal Ministry of Education and Research, and the Program for the Investment in the Future (ZIP) of the German Government to Luc Bovens, who co-directed the PPM Group with Stephan Hartmann. The publication of this book received further support from the Emmy Noether Junior Research Group Formal Epistemology at the Zukunftskolleg and the Department of Philosophy at the U- versity of Konstanz, directed by Franz Huber, and funded by the DFG. We thank everyone involved for their support. Dedicated to the memory of Philippe Smets and Henry Kyburg. Konstanz, Germany Franz Huber Christoph Schmidt-Petri v Contents Belief and Degrees of Belief…1 Franz Huber Part I Plain Belief and Degrees of Belief Beliefs, Degrees of Belief, and the Lockean Thesis…37 Richard Foley The Lockean Thesis and the Logic of Belief…49 James Hawthorne Partial Belief and Flat-Out Belief…75 Keith Frankish Part II What Laws Should Degrees of Belief Obey? Epistemic Probability and Coherent Degrees of Belief …