Abstract
In her book Extended Rationality: A Hinge Epistemology (2015), Annalisa Coliva puts forward an
anti-sceptical proposal based on the idea that the notion of rationality extends to the
unwarrantable presuppositions “that make the acquisition of perceptual warrants possible”
(2015: 150). These presuppositions are commonly the target of sceptical arguments, and by
showing that they are on the one hand unwarrantable, but on the other are constitutive
components of rationality itself, she reveals that they are beyond rational doubt and thus avoids
scepticism. Part of Coliva’s defence of using extended rationality in this way involves distancing it from
relativist interpretations, which she describes as “devastating” (2015: 120). She proposes two
ways that someone might attempt to formulate epistemic relativism from her extended rationality
view, and argues that both would be unsuccessful because they require describing alternative
conceptions of rationality which are “unintelligible” (in the first case), or “inconceivable” (in the
second). The superficial claim of this chapter is that Coliva’s arguments, as they stand, are insufficient to
dismiss relativism. She fails to show that the conception of rationality needed for the first
formulation of relativism is unintelligible, and overestimates the significance of the second
formulation’s conception turning out to be inconceivable. But I also highlight a deeper problem:
neither formulation follows a realistic blueprint for relativism, and so these were the wrong
possibilities to consider in the first place. To address this issue, I propose a third, more plausible,
way in which someone might attempt to formulate relativism on the basis of Coliva’s account. I
leave open whether this strategy is successful, or whether a version of Coliva’s criticisms apply to
it too.