Full Idea
Causal accounts of justification do not allow for the possibility that a false belief may still be justified.
Gist of Idea
Causal theories don't allow for errors in justification
Source
Jonathan Dancy (Intro to Contemporary Epistemology [1985], 2.4)
Book Reference
Dancy,Jonathan: 'Introduction to Contemporary Epistemology' [Blackwell 1985], p.35
A Reaction
Good. If you switch to what you only think is the cause of your belief, you have gone internalist and ruined the party. You can't deny that a falsehood can be justified, or justification is vacuous.