Tsohatzidis, Savas L.

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 1Pre-print; final version forthcoming in Philosophical Investigations Three Problems for the Knowledge Rule of Assertion Savas L. Tsohatzidis  Abstract. Timothy Williamson has argued that, unless the speech act of assertion were supposed to be governed by his so-called Knowledge Rule, one could not explain why sentences of the form ‘A and I do not know that A’ are unassertable. This paper advances three objections against that argument, of which the first two aim to show that, even assuming that Williamson’s explanandum has been properly circumscribed, his explanation would not be correct, and the third aims to show that his explanandum has not been properly circumscribed.     1. Introduction Compactly stated, Timothy Williamson’s theory of assertion is the following1:   Assertion is the unique speech act F whose unique constitutive rule is the knowledge rule:  (Knowledge Rule) One must: F that p only if one knows that p.  My purpose in what follows is to argue that Williamson’s main linguistic argument for the claim that the speech act of assertion is governed by the above-mentioned Knowledge Rule is not compelling.    Williamson’s main linguistic argument for the claim that assertion is governed by the Knowledge Rule is an abductive argument to the effect that it is only by assuming that assertion is so governed that one can explain why sentences of the form (X) are unassertable –that is, could not without oddity be asserted– even though what they would assert, if they could be asserted without oddity, could be true:   (X) A and I do not know that A.                                                   1 Cf. Williamson 1996; 2000: 238–269; 2009: 303ff, 341ff.  2Williamson’s proposed explanation of the unassertability of sentences of the form (X) is the following:   What is wrong [with sentences of the form ‘A and I do not know that A’] can easily be understood on the hypothesis that only knowledge warrants assertion. For then to have warrant to assert the conjunction ‘A and I do not know A’ is to know that A and one does not know A. But one cannot know that A and one does not know A. One knows the conjunction only if one knows each conjunct, and therefore knows that A (the first conjunct); yet one knows the conjunction only if it is true, so only if each conjunct is true, so only if one does not know that A (the second conjunct); thus the assumption that one knows the conjunction that A and one does not know that A yields a contradiction. Given that only knowledge warrants assertion, one therefore cannot have warrant to assert ‘A and I do not know that A’. 2  To recapitulate: Williamson’s chosen explanandum is the linguistic fact that sentences of the form (X) are unassertable, in the sense that they could not without oddity be asserted; his proposed explanation of this linguistic fact is that, on the assumption that the act of assertion is governed by the Knowledge Rule,  the unassertability of these sentences would follow from the fact that it would be logically impossible for their assertion to be warranted; and the fact that the Rule,  if it were assumed to be governing the act of assertion, would make that explanation possible constitutes, in Williamson’s view, a decisive reason for thinking that it does govern the act of assertion.  I will present three problems for Williamson’s argument, of which the first two show that, even assuming that Williamson’s explanandum has been properly circumscribed, his explanation would not be correct, and the third shows that his explanandum has not been properly circumscribed.    2. The first two problems The first two problems arise from cases where a sentence of the form (X) is unassertable, but its unassertability cannot be explained by Williamson’s account,                                                  2 Williamson 2000: 253; cf. Williamson 1996: 506.  3since that account is insensitive to the crucially relevant first-personal character of the sentences whose unassertability it sets out to explain.    (i)The case of the ignorant speaker Suppose that Helen Wilson is amnesiac about her name, and that, incorrectly believing that she is someone other than Helen Wilson, she utters the sentences in (1) and (2):  (1)  John is hiding and Helen Wilson doesn’t know that he is hiding. (2) It is five o’clock and Helen Wilson doesn’t know that it is five o’clock.  Sentences (1) and (2) are certainly assertable by Helen in the context just described.  However, sentences (3*) and (4*) –which, were they to be uttered by Helen in the same context, would have exactly the same truth conditions that (1) and (2) respectively have– are certainly unassertable ones:  (3*)  John is hiding and I don’t know that he is hiding.  (4*)  It is five o’clock and I don’t know that it is five o’clock.  The contrast between (1) and (2), on the one hand, and (3*) and (4*), on the other, shows that the reason why a sentence of the form (X) is unassertable cannot be the reason adduced by Williamson. According to Williamson, what makes a sentence of the form ‘A and I don’t know that A’ unassertable is that, applied to it, the Knowledge Rule entails that if one is to assert such a sentence one must “know that A and one does not know A”, which is a requirement that it is logically impossible to satisfy (“one cannot know A and one does not know A”); the hypothesis, then, that assertion is subject to the Knowledge Rule explains why such sentences are unassertable.  However, if that were the reason why (3*) and (4*) are unassertable by Helen, (1) and (2) should also be unassertable by her.  For, (1) and (2) have exactly the same truth conditions that (3*) and (4*), as uttered by Helen, would respectively have. So, if the unassertability of (3*) and (4*) by Helen were due to the fact that, given the Knowledge Rule, her assertion of them would commit her to satisfying logically unsatisfiable requirements, the same Knowledge Rule, applied to her utterances of (1)  4and (2), would commit her to satisfying the same logically unsatisfiable requirements, and so should prevent (1) and (2) from being assertable by her.  But since (1) and (2) are assertable by her, it follows that it is not any requirements entailed by the Knowledge Rule that explain why (3*) and (4*) are not assertable by her.  And since it was precisely its supposed capacity to explain the unassertability of sentences like (3*) and (4*) that justified, according to Williamson, the positing of the Knowledge Rule, it follows that Williamson’s argument fails to provide reasons for positing the rule in question.   (ii) The case of the ignorant addressees It might be thought that the sort of problem just noted can only be raised by reference to the atypical kind of case where, because of amnesia, a speaker does not know what his or her name is. In fact, however, exactly the same sort of problem can be raised by reference to the far from atypical type of case where an addressee happens not to know what the name of a speaker addressing him or her is. Suppose that Timothy Williamson is having a conversation with a group of people who are ignorant of the fact, and are known by Williamson to be ignorant of the fact, that their interlocutor’s name is “Timothy Williamson”. Suppose further that these people are asking Williamson questions like “Is the Bodleian Library closed? And if it is, does Timothy Williamson know that it is?” or “Is the Covered Market open? And if it is, does Timothy Williamson know that it is?” Finally, suppose that, for some important reasons of his own, Williamson wants these interlocutors to remain in their state of ignorance regarding his name (perhaps he has excellent grounds for thinking that they would seriously harm him if they were to know what they presently ignore). To safeguard his vital interests, Williamson might then choose to utter, in a confident and reassuring tone of voice, the following responses to the questions addressed to him by his interlocutors:  (5) The Bodleian Library is closed and Timothy Williamson doesn’t know that it is.  (6) The Covered Market is open and Timothy Williamson doesn’t know that it is.    5Sentences (5) and (6) are certainly assertable by Williamson, in the context just described.  However, sentences (7*) and (8*) –which, were they to be uttered by Williamson in the same context, would have exactly the same truth conditions that sentences (5) and (6) respectively have–,  are clearly unassertable ones:  (7*) The Bodleian Library is closed and I don’t know that it is.  (8*) The Covered Market is open and I don’t know that it is.   Just as in the previous type of case, the contrast between (5) and (6), on the one hand, and (7*) and (8*), on the other, shows that Williamson’s account of what explains the unassertability of sentences of the form (X) cannot be right.  According to that account, the reason why a sentence of the form ‘A and I don’t know that A’ is unassertable is that, applied to it, the Knowledge Rule entails that if one is to assert such a sentence one must “know that A and one does not know A”, which is a logically unsatisfiable requirement (“one cannot know A and one does not know A”); the hypothesis, then, that assertion is subject to the Rule explains why the sentences in question are unassertable. However, if that were the reason why (7*) and (8*) are unassertable by Williamson, (5) and (6) should also be unassertable by him.  For, (5) and (6) have exactly the same truth conditions that (7*) and (8*), as uttered by Williamson, would respectively have. So, if the unassertability of (7*) and (8*) by Williamson were due to the fact that, given the Knowledge Rule, his assertion of them would commit him to satisfying logically unsatisfiable requirements, the same Knowledge Rule, applied to his utterances of (5) and (6), would commit him to satisfying the same logically unsatisfiable requirements, and so should prevent (5) and (6) from being assertable by him.  But since (5) and (6) are assertable by him, it follows that it is not any requirements entailed by the Knowledge Rule that explain why (7*) and (8*) are not assertable by him.  And since it was precisely its supposed capacity to explain the unassertability of sentences like (7*) and (8*) that justified, according to Williamson, the positing of the Knowledge Rule, it follows that Williamson’s argument does not provide reasons for positing the rule in question.   3. The third problem  6Since, as the above problems make clear, the unassertability of sentences of the form (X) crucially depends on the fact, which is left out of consideration in Williamson’s explanation, that the subject of the knowledge-denials they contain is first-personal, Williamson’s abductive argument could not be saved unless the Knowledge Rule were somehow changed so as to become sensitive to that fact.  I cannot see any non-arbitrary way in which this could be done, but I will not pursue this matter further, since, as the problem to which I now turn shows, the explanatory project through which Williamson was aiming to justify the postulation of the Knowledge Rule would be bound to fail in any case.   The source of this further problem is that, contrary to what that project explicitly assumes, there exist not only unassertable but also assertable sentences of the first-personal form ‘A and I don’t know that A’.  Suppose a person accepts a form of determinism (call it ‘mysterian determinism’, to give it a name) according to which, although there is no such thing as free will, we are biologically engineered so as to be unable to ever know that there is no such thing as free will.  It would not be strange for a person who accepts this doctrine to produce, among others, modus ponens arguments like the following:   (9)  If I am not omniscient, my future actions are predetermined and I don’t know that they are. I am not omniscient. Therefore, my future actions are predetermined and I don’t know that they are.  It is clear that, in the context provided by its premises, the conclusion of this inference is not at all unassertable. However, the conclusion of the inference is an instance of schema (X), and therefore contradicts the basic assumption of Williamson’s explanatory project that there are no assertable instances of that schema. Notice that what Williamson was aiming to explain by positing the Knowledge Rule was that “Something is wrong with any assertion of the form ‘[A] and I do not know that [A],’ even though such assertions would often be true if made.”3  Not surprisingly, then, Williamson’s explanatory strategy breaks down when confronted with a sentence of the form (X) which, contrary to what the strategy assumes, is assertable. For, the fact                                                  3 Williamson 1996: 506; emphasis added.  7that such a sentence is assertable can then only be taken to mean either that there is no Knowledge Rule at all governing assertion or that, even supposing that assertion is governed by such a rule, the fact that it is so governed can do nothing to prevent the sentence’s assertability, and therefore is of no use in an abductive argument aiming to justify the rule’s postulation.  It might be claimed that assertable instances of schema (X) are confined to contexts of philosophical argument of the sort invoked by the inference in (9), and should, for that reason, be set aside for special treatment.  It is doubtful that the second part of this claim would be accepted as methodologically sound even if the first were true, but what is even more important to realize for present purposes is that the first part is simply not true: assertable instances of schema (X) can be encountered in perfectly ordinary contexts as well. For example, an ordinary speaker might very well produce the following instance of modus ponens:    (10)  If I am gullible, people lie to me and I don’t know that they do.  I am gullible.  Therefore, people lie to me and I don’t know that they do.   There is certainly nothing wrong with asserting the conclusion of this inference, given the context provided by its premises. The conclusion, however, is an instance of schema (X), and so its assertability falsifies Williamson’s assumption that “Something is wrong with any assertion of the form ‘[A] and I do not know that [A]’, even though such assertions would often be true if made”.  With that assumption gone, one would be entitled to conclude either that there is no Knowledge Rule at all that governs assertion or that, even if such a rule were on independent grounds supposed to govern assertion, its supposed existence would simply be irrelevant to understanding why some instances of schema (X) are unassertable and some others aren’t.  And, of course, since the assumption that the rule was not explanatorily irrelevant was the principal reason purportedly supporting the belief in its existence, Williamson’s abductive argument for its existence cannot be supposed to have been a successful one.   4. Conclusion  8I have given three reasons for thinking that Williamson’s main linguistic argument for the claim that assertion is governed by the Knowledge Rule is not compelling.  In view of the fact that, without the Knowledge Rule, there would be nothing left to Williamson’s account of assertion, that account itself, in so far as it relies on that argument, is not compelling either.  Concerning the linguistic phenomenon that had prompted Williamson’s argument, and which might legitimately be regarded as calling for an explanation, the outcome of the present discussion is that its adequate explanation, whatever it may finally turn out to be, should respect two conditions: First, it should be consistent with the fact that only some, and not all, instances of the schema ‘A and I don’t know that A’ are unassertable. Second, it should be consistent with the fact that, when an utterance that is an instance of that schema is unassertable, replacing its first-personal referring term with a co-referential non-first-personal referring term may result in a truth-conditionally equivalent utterance that is not unassertable. In short, and perhaps not unexpectedly, the phenomenon is considerably more complex than initial appearances might suggest.   Department of Linguistics Faculty of Philosophy Aristotle University of Thessaloniki    References Williamson, T. (1996). “Knowing and Asserting.” The Philosophical Review, Vol. 105, pp. 489–523.  Williamson, T. (2000). Knowledge and its Limits. Oxford: Oxford University Press. Williamson, T. (2009). “Replies to Critics.” In P. Greenough and D. Pritchard (eds.), Williamson on Knowledge. Oxford: Oxford University Press, pp. 279–384.  

Three Problems for the Knowledge Rule of Assertion

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Three Problems for the Knowledge Rule of Assertion

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