I think the answer lies in drawing two rather arbitrary boundaries: One between the world and the sensory system, and one between the sensory system and the mind. The actual grounding g is implemented by the sensory system. A spurious grounding g' is one that is not implemented, but that would produce the same propositions in K; so that the mind of K does not know whether it uses g or g'.

Does it matter if K could, in theory, dissect itself and observe its g? Would that in fact be possible; or is the fact that it needs to observe the implementation of its grounding g as viewed through g mean that it cannot distinguish between g and g', even by "autosection"?