Justified Belief, Reasons, and Evidence

Abstract

Normative reasons for belief—reasons to believe something—are constituted by truths or facts. Such reasons are distinguished from motivating reasons for belief, that is, reasons for which a subject believes something. These are constituted by considerations that the subject treats as reasons to believe. One has a justified belief, in the sense of a well-founded belief, only if the considerations that constitute one’s motivating reason are truths that one knows. Evidence-based knowledge that P is explicated in terms truths or facts that provide an adequate reason to believe that P. It is argued that not all knowledge is evidence-based, and suggested that we need to make sense of the idea that evidence adequate for knowledge is clinching evidence. The discussion addresses a problem raised by Jennifer Hornsby about the distinction between normative and motivating reasons.