Hm; are you saying you think FAI can probably be implemented without solving the logical uncertainty problem? My current visualization is that both the logical uncertainty problem and the safe rewrite problem will need to be solved -- among others -- and the reason I've been thinking about the rewrite problem is that using proof-based techniques, I at least had a grasp of how to think about it. (And my intuition has so far been that logical uncertainty will probably have diagonalization problems in a different guise when we actually have a concrete enough proposal to test this, so it seemed useful to think about the rewrite problem in the better-understood context, when trying to find in-principle solutions to the problems.)