Presupposition, Common Ground and Context

R. Stalnaker on Context and Content

In his seminal article "Pragmatics" (1970) Stalnaker proposed a conception of semantics and pragmatics that would allow the tools and traditions of formal semantics to be extended to pragmatics [9]. The pragmatic phenomena he mainly had in mind are what we are calling "near-side pragmatics," involving the way in which, in the setting of natural language, contextual factors interact with conventional meaning to determine what is said, or the proposition expressed. Stalnaker uses his pragmatic theory to deal with issues that might be thought to require a semantic explanation, such as the informativeness of identity statements ("Hesperus is Phosphorus") and the import of negative existentials ("Homer did not exist"); in doing so he saw himself as continuing in a Gricean tradition: “I think the general Gricean strategy of trying to reduce the burden on semantics by explaining as much of the phenomena as possible in terms of truisms about conversation as a rational activity remains as fruitful and promising as it was when he first proposed it” [9, p. 113].

Formal semantics, as Stalnaker sees it, can be conceived as the study of propositions within a possible worlds framework. Artificial languages are designed to fit the meanings they are to express, so the connection between language and proposition should not be a tricky issue. But with natural languages, “it is a semantical problem to specify the rules for matching up sentences of a natural language with the propositions that they express. In most cases the rules will not match sentences directly with propositions, but will match sentences with propositions relative to features of the context in which the sentence is used. These contextual features are a part of the subject matter of pragmatic” [9, p. 34].

Like Kaplan, Stalnaker has a two-tiered picture: sentence meanings provide a function from contexts to propositions; propositions themselves are functions from worlds to truth-values [7, 9]. Stalnaker, however, has a quite different picture of context, which he bases on the concept of presupposition. Intuitions about what is said are accompanied by intuitions about what is not said, but merely presupposed. If Elwood says,

1. The Queen of England has several palaces.

he does not say that there is a Queen of England, but he presupposes that there is.

Consider the following examples:

2. Peter knows the sea is salty.

3. It was James Madison that led America to defeat in the war of 1812.

4. Bush regrets invading Iraq.

5. Clinton resumed cheating on his wife.

In saying (2), Elwood would not say, but merely presuppose, that the sea is salty. In saying (3) he would presuppose, but not say, that some led America to defeat in the War of 1812. In saying (4) Elwood would presuppose that Bush invaded Iraq, and in (5) he would presuppose that Clinton had cheated on his wife, and then stopped doing so for a period of time (possibly rather short).

Presupposition has been treated as a semantic phenomenon and as a pragmatic phenomenon. Arguably, the negation of each of (1)-(5) would have the same presupposition. This has led to the semantic conception of presupposition as a non-trivial entailment that is shared by a statement and its negation. Semantical approaches to presupposition encounter some tricky problems, the most important of which is "the projection problem." If presupposition is semantic, then it seems the presuppositions of complex sentences should be a function of the presuppositions of the simple sentences that make them up, but it is at least not obvious that this is so. Consider, for example:

6. The king has a son.

7. The king's son is bald.

8. If the king has a son, the king's son is bald.

(6) presupposes that there is a king; (7) that there is a king and that the king has a son; (8) contains both (6) and (7). It seems to inherit the presupposition of (6) but not of (7); that is, (8) presupposes that there is a king, but not that he has a son. A correct theory of just how presuppositions are inherited from simple to complex sentences would solve the projection problem, and doing so seems to be required for a semantic account of presupposition.

Stalnaker recognizes semantic presupposition in the case of simple sentences (1)-(5). And he thinks that semantic presuppositions are also pragmatically presupposed; that is, if P is a semantic presupposition of what the speaker says, then the speaker will in fact take P for granted and take his audience to do so too; he will treat P as part of the common ground: “There is no conflict between the semantic and pragmatic concepts of presupposition; they are explications of related but different ideas. In general, any semantic presupposition of a proposition expressed in a given context will be a pragmatic presupposition of the people in the context, but the converse clearly does not hold. To presuppose a proposition in the pragmatic sense is to take its truth for granted, and to assume that others involved in the context do the same. The set of all the presuppositions made by a person in a given context determines a class of possible worlds, the ones consistent with all the presuppositions. This class sets the boundaries of the linguistic situation” [9, p. 38].

Stalnaker emphasizes that when we make assertions (the paradigmatic use of language, conceived as a tool for exchanging information), there is a natural division into what the speaker presupposes and what the speaker says. If Elwood says, "The Queen of England has charming grandchildren," he presupposes that there is a unique queen of England, and says that her grandchildren are charming. In the ordinary case, the presupposition would be shared by the conversational participants, but not everyone would already know, or believe, what Elwood says about her. The presuppositions that are shared are the common ground, which is an important part of the context of an utterance. Elwood's assertion is an attempt to add to the common ground that additional content that the queen's grandchildren are charming. Of course, someone may deny that this is so, in which case it wouldn't become part of the common ground. Nevertheless, we can conceptualize the meaning of a sentence, or a central part of the meaning of a sentence, in terms of the change a use of it attempts to make to the common ground.

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