Shohei Matsumoto

Presumptivism, or so-called anti-reductionism, of testimonial warrant is a controversial yet popular view in epistemology of testimony. Presumptivists argue that a hearer can have prima facie epistemic warrant to believe P if the hearer comprehends as of a speaker as asserting P. Among the defenders, Tyler Burge famously argued for presumptivism a priori, though not without significant challenge. Recently, Mona Simion presented another a priori argument for presumptivism based on the idea that assertions are governed by a social norm of truth-telling, calling her view “strong social anti-reductionism”. Subsequently, J. P. Grodniewicz provided another argument for presumptivism and also named his view “strong social anti-reductionism”, following Simion. The purpose of this paper is to elucidate their “strong social anti-reductionist” arguments, illuminate the problems in their views, and examine which variant(s) of presumptivist positions the “social anti-reductionist” approach may support. I start by clarifying Simion’s commitments and reconstructing her argument, and demonstrate that Simion fails to provide a sound argument for her position. Then I argue that Grodniewicz’s position should be understood as more moderate than Simion’s, and that while his defense of presumptivism is promising, two issues need to be resolved: First, what version of presumptivism is argued for remains unclear; second, it still suffers from what Simion called “the Source Problem”, or what Sanford Goldberg called “the problem of easy entitlements”. To address these challenges, Grodniewicz’s view needs to be integrated with a robust theory of warrant, for which I suggest that Peter Graham’s warrant functionalism is a suitable candidate. Lastly, I will briefly explore presumptivist positions that align with Grodniewicz’s “social anti-reductionist” framework.