Ignorance That Excuses

Abstract This chapter explores when ignorance is an excuse. It first spells out what it is to be excused for something: one did something wrong by violating an obligation and one is blameless for that. Next, it is argued that an excuse can be provided by ignorance of four kinds of propositions: ignorance of one’s having the obligation in question, ignorance of one’s having the ability to meet that obligation, ignorance of how to meet that obligation, and lack of foresight regarding that obligation. It follows that normative ignorance can excuse as well as factive ignorance. Moreover, there are important differences between the extents to which varieties of ignorance excuse. Disbelieving, unconsidered, deep, and complete ignorance normally fully excuse, whereas suspending and undecided ignorance provide at most a partial excuse. Practical and objectual ignorance can excuse as well. Finally, it is considered when ignorance counts as an excuse for a group.