Is Forgotten Evidence a Problem for Evidentialism?

The “problem of forgotten evidence” is a common objection to evidentialist theories of epistemic justification. This objection is motivated by cases where someone forms a belief on the basis of supporting evidence and then later forgets this evidence while retaining the belief. Critics of evidentialist theories argue that in some of these cases the person's belief remains justified. So, these critics claim that one can have a justified belief that is not supported by any evidence the subject possesses. I argue that these critics are mistaken.