Same, same but different: the epistemic norms of assertion, action and practical reasoning

What is the relationship between the epistemic norms of assertion and the epistemic norms of action/practical reasoning? Brown argues that the standards for practical reasoning and assertion are distinct (Brown 2012). In contrast, Montminy argues that practical reasoning and assertion must be governed by the same norm (Montminy 2012). Likewise, McKinnon has articulated an argument for a unified account from cases of isolated second-hand knowledge (McKinnon 2012). To clarify the issue, I articulate a distinction between Equivalence Commonality and Structural Commonality. I then argue against the former by counterexamples that doubly dissociate the standards for assertion and action. Furthermore, I argue that such a double dissociation compromises knowledge accounts of both assertion and action/practical reasoning. To provide a more accurate diagnosis, I consider speech act theory and argue that principled differences between the norms of action and assertion compromise Equivalence Commonality. In contrast, a qualified version of Structural Commonality may be preserved.