Moral error theorists often respond to the epistemic companions in guilt strategy by adopting the Disparity Response: reject the putative parity between moral and epistemic reasons and claim that though the former are irreducibly normative, the latter aren’t. I argue such a response fails. Expanding on Das’ Australas J Philos 95(1):58–69, (2017) work I present a master argument against Disparity Responses: the arguments moral error theorists use to advance their conceptual claim apply in the epistemic domain also. This prohibits the error theorist from adopting epistemic reductionism. I use Jonas Olson’s work as exemplary of moral error theory. I demonstrate that Olson’s (2014) argument that the rhetorical authority of moral claims is best ...