Online research in philosophy

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.

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.

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.

I am currently examining the suggestion that assertion and practical reasoning are subject to specifically epistemic norms, and the consequences of this suggestion for the correct account of knowledge. One currently popular view is that knowledge is the epistemic norm of both assertion and practical reasoning (see DeRose, Hawthorne, Stanley and Williamson). If assertion and practical reasoning are governed by the knowledge norm, then one criterion for an account of knowledge is that it should respect the ties between knowledge, assertion and practical reasoning. In this way, the knowledge norm is at the heart of contemporary debate about the correct account of knowledge, e.g. the debate between contextualism and invariantism (see Hawthorne.

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.

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.

In this paper, I take up an argument advanced by Keith DeRose (Philosophical Review, 111:167–203, 2002) that suggests that the knowledge account of assertion provides the basis of an argument in favor of contextualism. I discuss the knowledge account as the conjunction of two theses—a thesis claiming that knowledge is sufficient to license assertion KA and one claiming that knowledge is necessary to license assertion AK. Adducing evidence from Stalnaker’s account of assertion, from conversational practice, and from arguments often raised in favor of the knowledge account, I suggest that neither the AK nor the KA theses are plausible. That is, I argue that the knowledge account of assertion to which DeRose appeals is in fact not suitable as an account of assertion. Given that DeRose’s argument stands and falls with the knowledge account, I claim that the argument therefore fails.

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.

Keith DeRose has recently argued that the contextual variability of appropriate assertion, together with the knowledge account of assertion, yields a direct argument that ’knows’ is semantically contextsensitive. The argument fails because of an equivocation on the notion of warranted assertability. Once the equivocation is removed, it can be seen that the invariantist can retain the knowledge account of assertion and explain the contextual variability of appropriate assertion by appealing to Williamson’s suggestion that practical and conversational considerations can influence the extent to which adherence to the constitutive norm of assertion matters.

We argue against the knowledge rule of assertion, and in favour of integrating the account of assertion more tightly with our best theories of evidence and action. We think that the knowledge rule has an incredible consequence when it comes to practical deliberation, that it can be right for a person to do something that she can’t properly assert she can do. We develop some vignettes that show how this is possible, and how odd this consequence is. We then argue that these vignettes point towards alternate rules that tie assertion to sufficient evidence-responsiveness or to proper action. These rules have many of the virtues that are commonly claimed for the knowledge rule, but lack the knowledge rule’s problematic consequences when it comes to assertions about what to do.