You’d need some coupling argument to know that the problems have related difficulty, so that if A is constantly saying “I don’t know” to other similar problems it counts as evidence that A can’t reliably know the answer to this one. But to be clear, we don’t know how to make this particular protocol go through, since we don’t know how to formalise that kind of similarity assumption in a plausibly useful way. We do know a different protocol with better properties (coming soon).
You’d need some coupling argument to know that the problems have related difficulty, so that if A is constantly saying “I don’t know” to other similar problems it counts as evidence that A can’t reliably know the answer to this one. But to be clear, we don’t know how to make this particular protocol go through, since we don’t know how to formalise that kind of similarity assumption in a plausibly useful way. We do know a different protocol with better properties (coming soon).