Abstract

This paper offers a new solution to what Plantinga has called the Conditionalization Problem—the challenge of identifying which auxiliary beliefs can legitimately deflect the rebutting defeater for the reliability of our cognitive faculties (R) generated by the conjunction of naturalism and evolution (N&E). After critically evaluating Andrew Moon’s Epistemic-Origin Solution—which fails to provide necessary conditions for defeater-deflection—I develop a more comprehensive account grounded in four jointly sufficient conditions: the Defeater-Deflector Adequacy Condition (DDAC), Evidential-Independence, Non-Ad-Hocness, and Noetic Undefeatedness. This account preserves Plantinga’s core constraints while delivering the correct verdicts across a wide range of cases, including those in which Moon’s proposal falters. Finally, I argue that this solution undermines the Defeater Thesis (DT), thereby showing that the EAAN is unsound.