Good points, but then likewise how do you define and import the designations of 'hand' or 'here' and justify intuitions or a axiomatic system of logic (and I understood Carrier to be referring to epistemic solipsism like Moore -- you seem to be going metaphysical)? (or were you not referring to Moore's argument in the context of skepticism?)
I think Moore's basic argument works on the level of epistemic skepticism, yes, but also metaphysics: some sort of regular metaphysics and externalism is what one believes, and what provides the grist for the philosophical mill. If you don't credit the regular metaphysics, then why do you credit the reasoning and arguments which led you to the more exotic metaphysics?
I'm not sure what skeptical arguments it doesn't work for. I think it may stop at the epistemic level, but that may just be because I'm having a hard time thinking of any ethics examples (which is my usual interest on the next level down of abstraction).
Here's the new thread for posting quotes, with the usual rules: