Models of communication

Perhaps the best way of capturing the cognitive nature of assertion is to to give a theory of the cognitive features of normal communication by means of assertion. A classic theory is Stalnaker's (1974, 1978). Stalnaker provides a model of a conversation in which assertion and presupposition dynamically interact. On Stalnaker's model, propositions are presupposed in a conversation if they are on record as belonging to the common ground between the speakers. When an assertion is made and accepted in the conversation, its content is added to the common ground, and the the truth of the proposition in question will be presupposed in later stages. What is presupposed at a given stage has an effect on the interpretation of new utterances made at that stage. Stalnaker uses a possible worlds framework, and characterizes the common ground as a set of possible worlds (the worlds where all that is presupposed is true), the context set.
In this framework Stalnaker (1978: 88–89) proposes three rules for assertion:

(Stal)i.A proposition is always true in some but not in all of the possible worlds in the context set.
ii.Any assertive utterance should expresses a proposition, relative to each possible world in the context set, and that proposition should have truth value in each possible world in the context set.
iii.The same proposition is expressed relative to each possible world in the context set.

Stalnaker comments on the first rule:

اقتباس :: To assert something incompatible with what is presupposed is self-defeating […] And to assert something which already presupposed is to attempt to do something that is already done.

On such an approach, the satisfaction of a presupposition is an admittance condition of an assertion (cf. Karttunen 1974; Heim 1983). This idea connects with Austin's more general pragmatic idea of felicity conditions of speech acts.
However, as was already pointed out by Stalnaker (1974: 55), and later stressed in Lewis (1979), an assertion that intuitively presupposes the truth of another proposition need not fail, but can instead have the effect of adjusting the common ground. In so-called accommodation, the hearer adds background assumptions that would be required for interpretation. For instance, upon hearing Lewis utter

(34)The cat has gone upstairs

the hearer who didn't know may accommodate by adding the assumption that there is a unique, contextually salient cat. Accommodation is further discussed in Stalnaker (2002), where it is stressed, among other things, that it works, when it works, because of what is already presupposed. For example (34), it is presupposed that the speaker knows whether or not he has a cat.
Whatever the truth about presupposition accommodation, Stalnaker offers a model of the cognitive features of communication and the role of assertion therein. Does it thereby also offer an account of assertion? The answer is no, for the role of assertion is shared by other speech acts such as assuming and conjecturing. What is added to the common ground is only for the purpose of conversation, and need not be actually believed by the participants. It is only required that it beaccepted (cf. Stalnaker 2002: 716).
Stalnaker has not (as far as I am aware) attempted to add a distinguishing feature of assertion to the model. This has, however, been attempted by Jonathan Schaffer (2008) and by Max Kölbel (2011: 68–70). Schaffer proposes to add a topic-sensitive knowledge norm (cf. subsection 6.2) to the Stalnakerian picture. Kölbel focuses on commitments instead. According to Kölbel, assumptions differ from assertion in two respects. Firstly, they are temporary, which means that they can be revoked when they have served their purpose. Secondly, they do not have the same commitment properties. On Kölbel's view, an assertion that [ltr]p[/ltr] is made with the (Brandomian) undertaking of the “obligation to justify that [ltr]p[/ltr] on request”. This undertaking, according to Kölbel, also distinguishes assertion from presupposition, although in a more subtle way. It is not, however, clear why in Kölbel's view, Stalnaker's account would be needed in addition to the obligation property.
Another cognitive account is offered by Pagin (2011). The account is summarized by the phrase: “an assertion is an utterance that is prima facie informative”. For an utterance to be informative is for it to be made in part “because it is true”. What this amounts to is different, but complementary, for speaker and hearer. For the speaker, part of the reason for using a particular sentence is that it is true (in context); that is, the speaker believes, with a sufficient strength, that the sentence expresses a true proposition. For the hearer, taking the utterance as informative, means, by default, to update his credence in the proposition as a response to the utterance, both in the upwards direction and to a level above 0.5.
The prima facie element of the account means that the typical properties on the speaker and hearer side are only default properties associated with surface features of the utterance: the declarative sentence type, a typical intonation pattern, etc. There are many possible reasons why a speaker my utter such a sentence without believing the proposition, and why a hearer may not adjust his credence in the typical manner. For example, the speaker may be lying, the hearer may distrust the speaker, or may already have given the proposition a very high credence before the utterance. On Pagin's picture, it is the cognitive patterns associated with surface features, on the production and comprehension sides, that characterize assertion. This way of dividing the account between speaker and hearer is somewhat controversial.
Yet another cognitive account is elaborated in Jary (2010). Jary's account is situated withinRelevance Theory, a more general account of cognition and communication. As a typical ingredient of this general framework, when an assertion is made, the proposition expressed by the utterance is presented as “relevant to the hearer” (2010: 163), where ‘relevant’ is a technical term (Sperber & Wilson 1995: 265).
What distinguishes assertion from other speech act types is something different:

اقتباس :: Assertion cannot be defined thus, though. In order for an utterance to have assertoric force, it must also be subject to the cognitive and social safeguards that distinguish assertion. […] It is the applicability of these safeguards that distinguishes assertion both from other illocutionary acts and from other forms of information transfer. (Jary 2010: 163–4)

Social safeguards consist in sanctions against misleading assertions, while cognitive safeguards consist in the ability of the hearer to not simply accept what is said but meta-represent the speaker as expressing certain beliefs and intentions (2010: 160). It is part of a full account of assertion, according to Jary, that assertions are subject to these safeguards. This also distinguishes assertions from promises and commands, where the proposition is not presented as subject to the hearer's safeguards; “rejection is not presented as an option for the hearer” (2010: 73).
Although Jary's account no doubt captures some of the cognitive ingredients in producing and comprehending assertions, it seems also to be a fairly liberal mixture of social character accounts and communicative intentions accounts. One wonders whether it is impossible to make assertions without the existence of social sanctions, and how plausible it is to suppose the average speaker to intend his utterance to be subject to the hearer's ability to meta-represent the speaker.

Models of communication

Models of communication :: تعاليق

Models of communication