Assertion: knowledge is enough


Recent literature features an increased interest in the sufficiency claim involved in the knowledge norm of assertion (KNA-Suff). This paper looks at two prominent objections to KNA-Suff, due to Jessica Brown and Jennifer Lackey, and argues that they miss their target due to value-theoretic inaccuracies. It is argued that (i) the intuitive need for more than knowledge in Brown’s high-stakes contexts does not come from the epistemic norm governing assertion, but from further norms stepping in and raising the bar, and (ii) Lackey’s purported quality-driven case against KNA-Suff boils down to a quantitative objection. If that is the case, Lackey’s argument will be vulnerable to the same objections as Brown’s.

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  1. 1.

    For support for KNA along these lines, see e.g., Reynolds (2002), Kelp (2015), Simion (2015).

  2. 2.

    The locus classicus for the defence of KNA-Nec is Williamson (2000).

  3. 3.

    E.g., DeRose (2002), Simion (2015) and, more tentatively, Hawthorne (2004).

  4. 4.

    For the sake of simplicity, I will use ‘proper’ and ‘permissible’ interchangeably. One might object to this, due to phenomena related to super- and suberogation. For the purposes of this paper, however, nothing hinges on this.

  5. 5.

    Note that Brown’s case, as it stands, is somehow under-described; that is, it is not at all clear what could ground Friend’s belief in the affair such that it would intuitively amount to knowledge, but fall short of assertability. Seeing the couple in a fugitive embrace? Seems to fall short of being enough for knowledge. On the other hand, it looks as if anything more than that would come close to providing enough epistemic support for assertability. For the purposes of this paper, however, I will take it that there is a way to fill out the case such that it ends up doing the intended work.

  6. 6.

    Notice that the claim needed for this argument is of mere association between norms and goals of a particular type; as such, it does not, in any way, imply any substantive value theoretic commitments. The consequentialist will explain the ‘ought’ in terms of the ‘good’; he will say that the norm is there to guide us in reaching the goal. As opposed to this, the deontologist reverses the order of explanation; he would have it that the goal is only valuable in virtue of the fact that the norm gives us reasons to favour it. Anyhow, the mere association claim holds. Thus, the argument made by this paper can be constructed in both consequentialist and deontological terms; nothing here hinges on this.

  7. 7.

    One way for Brown to argue that it is for the sake of reaching an epistemic goal that more warrant is needed in this case could go along the following lines: Friend’s assertion is aimed at generating knowledge/true belief in his audience—in this case, Husband. If Friend were to assert ‘Your wife is having an affair’, Husband might plausibly ask ‘How do you know?’ In this case, Husband might fail to believe the content of Friend’s assertion if the latter is not able to back his claims by serious epistemic support. If Friend fails to generate belief in his audience, he also thereby fails to generate knowledge, or true belief, for that matter, so he fails to reach his epistemic goal (thanks to XXX for pressing me on this one).

    Notice, however, that a norm of assertion that would be able to accommodate this case would be implausibly strong; not only would it be asking for a high quantity of warrant in high stakes scenarios, but also for the speaker to have access to it, so that he can discursively justify his speech act. This, however, seems to over-intellectualize the practice of assertion. Children, for instance, due to lacking the cognitive sophistication to reflect on their warrant, would never be allowed to assert in high stakes circumstances. And if this still does not look bad enough, consider also the fact that most of our knowledge comes from memory. Now, in most cases of memorial knowledge that p, we tend to not recall how we came to know that p in the first place. I surely know that Berlin is the capital of Germany, that I was born in January, that the Sears Tower is in Chicago, and so on, but I have no clue as to how I came across all this. Does that mean that I am not allowed to assert any of this in high stakes scenarios? That seems highly implausible. Or, to say the least, I believe it to be on Brown’s shoulders to construct a good case for such a demanding norm.

  8. 8.

    In this case, KNA-Nec. Notice also that no one in the literature questions the prudential explanation in the TRAIN case. However, TRAIN is for KNA-Nec what AFFAIR is for KNA-Suff: a case in which the quantity of epistemic warrant needed for prudentially proper assertion is not the same as the one needed for epistemically proper assertion. It is, therefore, surprising that AFFAIR is seen as problematic for KNA-Suff, while TRAIN is widely acknowledged to not put any pressure on KNA-Nec.

  9. 9.

    I do not claim to even come close to settling this issue here. For a more detailed discussion, see Simion (2015).

  10. 10.

    Lackey (2013, p. 40) acknowledges that the purely testimonial source is enough to trigger unassertability.

  11. 11.

    For a similar project but a quite different objection to Lackey’s expert testimony cases see Benton (2014). Although Benton’s case against Lackey goes along quite dissimilar lines to the one made by this paper, Benton too seems to be sympathetic to the idea of further norms stepping in due to the high-stakes institutional contexts. See, for instance, footnote 12, p. 9. For Lackey’s reply to Benton’s objections, see Lackey (2014).

  12. 12.

    Weaker norms are broken too: e.g., the speaker is not even justified in believing the implicature.

  13. 13.

    For further support for this claim, see McGlynn (2014, p. 128).

  14. 14.

    For an argument against the claim that one has to know the conversational implicatures of one’s assertions, see Fricker (2012); while I find Fricker’s argument successful, I think that the case this paper is making is not affected by it. Roughly, Fricker takes it that we might not be able to hold the speaker responsible for lack of warrant for the generated conversational implicatures, because in many contexts it is not clear whether the hearer gets the implicature right. However, importantly, Fricker’s argument only targets (and, arguably, only goes through for) mere conversational implicatures. The ones this paper is concerned with are conventional conversational implicatures, that is, carried by the meaning with which the sentence is conventionally (usually) uttered (more about this below). Roughly put, it looks as if, if a sentence is conventionally uttered with a particular meaning, the hearer is in a better position to get the implicature right, and therefore in a better position to criticize the speaker for lack of warrant.

  15. 15.

    Notice the Gricean flavor here.

  16. 16.

    Lackey (2011, 2013) brings two further cases in support of her view: a case involving someone’s second-hand knowledge that a student cheated in an exam, and a case of moral testimony. In both cases, Lackey takes it that the subjects (i) have the relevant piece of knowledge from testimony, and (ii) still fail to be in a position to make epistemically proper assertions.

    Arguably though, both cases fall short of fully driving the point home; the former case fails to trigger a clear unassertability intuition, while the claim to knowledge acquisition in the latter case is disputed in the relevant literature; as such, for the purposes of this paper, I decided to focus on the less controversial cases. For a very convincing case against Lackey’s claim (ii) for the cheating student scenario, see McGlynn (2014, p. 128). For problems with claim (i) for the moral testimony case, see Lackey’s (2013, p. 33) overview of the relevant literature.


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Many thanks to Chris Kelp, Harmen Ghijsen and Jan Heylen for all the help with this paper and to Chris Kelp’s ‘Knowledge First Virtue Epistemology’ project for financing the research leading to its completion.

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Correspondence to Mona Simion.

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Simion, M. Assertion: knowledge is enough. Synthese 193, 3041–3056 (2016).

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  • Knowledge norm
  • Assertion
  • Sufficiency
  • Brown
  • Lackey