Full Idea
The key issue in belief revision is whether one needs to keep track of one's original justifications for beliefs. What I am calling the 'foundations' theory says yes; what I am calling the 'coherence' theory says no.
Gist of Idea
In revision of belief, we need to keep track of justifications for foundations, but not for coherence
Source
Gilbert Harman (Change in View: Principles of Reasoning [1986], 4)
Book Reference
Harman,Gilbert: 'Change in View: Principles of Reasoning' [MIP 1986], p.29
A Reaction
I favour coherence in all things epistemological, and this idea seems to match real life, where I am very confident of many beliefs of which I have forgotten the justification. Harman says coherentists need the justification only when they doubt a belief.