I offer a new epistemic paradox, which I call “the specialist paradox”, according to which specialist knowledge, that is, complete knowledge of an aspect of the world, is impossible. I offer a solution to it, after which I argue that the paradox represents a challenge to the epistemic arguments against physicalism, especially to the famous knowledge argument against physicalism, which comes out as simply an instance of the paradox rather than as a bona fide argument. However, accepting the solution to paradox entails rejecting the conjunction of the premises of the knowledge argument as unassertible. The result is extended to other epistemic arguments against physicalism, and agnosticism in the form of the so-called quandary view, due to Crispin Wright, is advocated about the mind-body problem in general.