ABSTRACT: Joel Pust has recently challenged the Thomas Reid-inspired argument against the reliability of the a priori defended by Alvin Plantinga, Nicholas Wolterstorff, William Alston, and Michael Bergmann. The Reidian argument alleges that the Cartesian insistence on the primacy of a priori rationality and subjective sensory experience as the foundations of epistemic justification is unwarranted because the same kind of global skeptical scenario that Cartesians recognize as challenging the legitimacy of perceptual beliefs about the external world also undermine the reliability of a priori rationality. In reply, Pust contends that some a priori propositions are beyond doubt and that fact can be used to support the overall reliability of reason. This paper challenges Pust’s argument. I argue that while Pust successfully undermines a radical skeptical view of reason, he does not refute a more modest skepticism. I conclude with some suggestions for Cartesian a priorists.