Full Idea
A characteristic case in which a belief is justified though the cognizer doesn't know that it's justified is where the original evidence for the belief has long since been forgotten.
Gist of Idea
A belief can be justified when the person has forgotten the evidence for it
Source
Alvin I. Goldman (What is Justified Belief? [1976], II)
Book Reference
'Epistemology - An Anthology', ed/tr. Sosa,E. /Kim,J. [Blackwell 2000], p.348
A Reaction
This is a central problem for any very literal version of internalism. The fully rationalist view (to which I incline) will be that the cognizer must make a balanced assessment of whether they once had the evidence. Were my teachers any good?