Full Idea
According to Kitcher, if experiential evidence can defeat someone's justification for a belief, then their justification depends on the absence of that experiential evidence.
Gist of Idea
If experiential can defeat a belief, then its justification depends on the defeater's absence
Source
report of Philip Kitcher (The Nature of Mathematical Knowledge [1984], p.89) by Albert Casullo - A Priori Knowledge 2.3
Book Reference
'Oxford Handbook of Epistemology', ed/tr. Moser, Paul K. [OUP 2002], p.105
A Reaction
Sounds implausible. There are trillions of possible defeaters for most beliefs, but to say they literally depend on trillions of absences seems a very odd way of seeing the situation