Finally, (a) the justification for the normative and the non-normative premises must be provided by some source of evidence or justification other than intuitions of the sort impugned by the argument and (b) we must lack good reason to think that our belief in the normative or factual premise fails the necessary condition on justified belief advanced by the normative premise. Call the conjunction of these requirements “the non-self-undermining constraint” (Bealer 1992; Pust 2001; but see Silva 2