Online research in philosophy

John Turri has recently provided two problem cases for the knowledge account of assertion (KAA) to argue for the express knowledge account of assertion (EKAA). We defend KAA by explaining away the intuitions about the problem cases and by showing that our explanation is theoretically superior to EKAA.

According to the knowledge account of assertion, an assertion that p is correct just in case the speaker knows that p. This is so because of a norm that governs assertion and uniquely characterizes it. Recent opposition to the knowledge account accepts that assertion is governed by a norm, but proposes alternatives to the knowledge norm. In this paper I focus on some difficulties for normative accounts of assertion.

John N. Williams (1994) and Matthew Weiner (2005) invoke predictions in order to undermine the normative relevance of knowledge for assertions; in particular, Weiner argues, predictions are important counterexamples to the Knowledge Account of Assertion (KAA). I argue here that they are not true counterexamples at all, a point that can be agreed upon even by those who reject KAA.

The Knowledge Account of Assertion (KAA) has received added support recently from data on prompting assertion (Turri 2010) and from a refinement suggesting that assertions ought to express knowledge (Turri 2011). This paper adds another argument from parenthetical positioning, and then argues that KAA’s unified explanation of some of the earliest data adduced in its favor recommends KAA over its rivals.

The oddities in lottery cases and Moore’s paradox appear to support the knowledge account of assertion, according to which one should assert only what one knows. This paper preserves an emphasis on epistemic norms but presents grounds for an alternative explanation. The alternative divides the explanandum, explaining the error in lottery and Moorean assertions with one move and their deeper incoherence with another. The error derives from a respect in which the assertions are uninformative: the speaker is not being appropriately responsive to her addressee’s epistemic needs. And the incoherence derives from a deeper respect in which lottery and some (but not all) Moorean assertions are uninformative: it is difficult to see how the speaker’s assertion could express any judgment she has made or would relevantly make, since she transparently lacks epistemic authority to inform any conceivable interlocutor on the subject. This diagnosis suggests an epistemic approach not directly to assertion but to judgment. Without judging that p, how could a speaker be in the business of informing her addressee that p? If the speaker transparently lacks authority to inform anyone whether p – to give anyone her word that p – how could she without confusion count as judging that p?

Taking Per Martin-Löf’s constructive type theory as a starting-point a theory of assertion is developed, which is able to account for the epistemic aspects of the speech act of assertion, and in which it is shown that assertion is not a wide genus. From a constructivist point of view, one is entitled to assert, for example, that a proposition A is true, only if one has constructed a proof object a for A in an act of demonstration. One thereby has grounded the assertion by an act of demonstration, and a grounding account of assertion therefore suits constructive type theory. Because the act of demonstration in which such a proof object is constructed results in knowledge that A is true, the constructivist account of assertion has to ward off some of the criticism directed against knowledge accounts of assertion. It is especially the internal relation between a judgement being grounded and its being known that makes it possible to do so. The grounding account of assertion can be considered as a justification account of assertion, but it also differs from justification accounts recently proposed, namely in the treatment of selfless assertions, that is, assertions which are grounded, but are not accompanied by belief.

It is often argued that the general propriety of challenging an assertion with 'How do you know?' counts as evidence for the Knowledge Norm of Assertion (KNA). Part of the argument is that this challenge seems to directly challenge whether a speaker knows what she asserts. In this paper I argue for a re-interpretation of the data, the upshot of which is that we need not interpret 'Hod do you know?' as directly challenging a speaker's knowledge; instead, it's better understood as challenging a speaker's reasons. Consequently, I argue that reasons-based norms can equally well explain this data.

The knowledge account of assertion—roughly: one should not assert what one does not know—aspires to identify the norm distinctive of assertion. One main argument given in support of the knowledge account has been the success with which it explains a variety of Moore-paradoxical assertion. But that explanation does not generalize satisfactorily.

We show that the contemporary debate surrounding the question “What is the norm of assertion?” presupposes what we call the quantitative view, i.e. the view that this question is best answered by determining how much epistemic support is required to warrant assertion. We consider what Jennifer Lackey ( 2010 ) has called cases of isolated second-hand knowledge and show—beyond what Lackey has suggested herself—that these cases are best understood as ones where a certain type of understanding , rather than knowledge, constitutes the required epistemic credential to warrant assertion. If we are right that understanding (and not just knowledge) is the epistemic norm for a restricted class of assertions, then this straightforwardly undercuts not only the widely supposed quantitative view, but also a more general presupposition concerning the universalisability of some norm governing assertion—the presumption (almost entirely unchallenged since Williamson’s 1996 paper) that any epistemic norm that governs some assertions should govern assertions—as a class of speech act—uniformly.

Many philosophers favour the simple knowledge account of assertion, which says you may assert something only if you know it. The simple account is true but importantly incomplete. I defend a more informative thesis, namely, that you may assert something only if your assertion expresses knowledge. I call this 'the express knowledge account of assertion', which I argue better handles a wider range of cases while at the same time explaining the simple knowledge account's appeal. §1 introduces some new data that a knowledge account of assertion well explains. §2 explains the simple knowledge account's advantage over two of its main competitors. §3 presents a problem for the simple account and offers a solution, which is to adopt the express knowledge account. §4 encapsulates the case for the express knowledge account, and offers a unifying vision for the epistemology of belief and assertion. §5 answers an objection. §6 briefly sums up. Even those who ultimately reject my conclusion can still benefit from the new data presented in §1, and learn an important lesson from the problem discussed in §3, which demonstrates a general constraint on an acceptable account of the norm of assertion.