Defeaters and higher-level requirements

Internalists tend to impose on justification higher-level requirements, according to which a belief is justified only if the subject has a higher-level belief (i.e., a belief about the epistemic credentials of a belief). I offer an error theory that explains the appeal of this requirement: analtically, a belief is not justfied if we have a defeater for it, but contingently, it is often the case that to avoid having defeaters, our beliefs must sake a higher-level requirement. I respond to the objection that externalists who endorse this error theory will be forced to accept a radical form of scepticism.