Because externalists deny that we need to know that a method is trustworthy before it can confer justification on our beliefs, they see nothing amiss with arguments for the trustworthiness of a method that rely on the deliverances of that same method. By denying that epistemically circular arguments are vicious, externalists reject the Agrippan challenge rather than answering it. While this may be a viable response to Pyrrhonian scepticism, it cannot suffice as a response to epistemic relativism because cases of epistemic incommensurability can be rationally resolved only by means of suasive justifications that epistemically circular arguments cannot deliver. The chapter concludes by re-formulating the argument for epistemic relativism in light of this insight.