 Belief comes in a qualitative (full) form, as when Sophia believes that Vienna is the capital of Austria, and a quantitative (partial) form, as when Sophia's belief that Vienna is the capital of Austria is stronger, in some sense, than her belief that Vienna is more populous than Budapest. The question of how full and partial belief are related has received considerable attention in formal epistemology, giving rise to several subtle, elegant and, unfortunately, incompatible solutions. The debate between these alternatives is a particular focus of this entry, covered in Section 4. 