Full Idea
Even weak internalism has the problem of Forgotten Evidence; the agent once had adequate evidence that she subsequently forgot; at the time of epistemic appraisal, she no longer has adequate evidence that is retrievable from memory.
Gist of Idea
Internalism must cover Forgotten Evidence, which is no longer retrievable from memory
Source
Alvin I. Goldman (Internalism Exposed [1999], §3)
Book Reference
Goldman,Alvin I.: 'Pathways to Knowledge' [OUP 2002], p.10
A Reaction
This is certainly a basic problem for any account of justification. It will rule out any strict requirement that there be actual mental states available to support a belief. Internalism may be pushed to include non-conscious parts of the mind.