Assertion and Isolated Second-Hand Knowledge

Abstract

A debate has emerged whether assertions based on testimony are warrantedly assertible when they’re epistemically grounded in what Jennifer Lackey (2011) calls isolated second-hand knowledge (ISHK).¹ Over-simplifying for the moment, Lackey argues that when the epistemic support for a speaker’s assertion is merely grounded in ISHK, even though the speaker knows what she asserts, the epistemic support is insufficient to warrant the assertion. She takes this as evidence against the view that knowledge-is-sufficient epistemic support for proper assertion. This is a problem for a wide variety of assertoric norms, possibly including SRN. Carter and Gordon (2011) take Lackey’s argument to suggest that the “quantity” view of assertion — that the central issue involved in understanding norms of assertion involves articulating the required quantity of epistemic support, whether it’s truth, justification, knowledge, or certainty — is mistaken. Instead, what’s required is a norm (or norms) sensitive to the requirements of the quality of a speaker’s epistemic support for her assertion.²