NoR 4.1: Fixing linguistic interpretation.

This is one of a series of posts setting out my work on the Nature of Representation. You can view the whole series by following this link. 

The non-representational world contains causes and functions. From these primordial elements arises the intentionality of perception and (contrastive) intention. Perceptions and intentions in the life of a single creature then ground beliefs and desires. What mediates between perception/intention and belief/desire is rationalization. If the states that will end up as vehicles of content are patterned in interesting ways, then truths about rationality allow us to derive succinct explanations why the elements of those states represent what they do.

In this new subsequence of posts, I’m going to extend this to “third layer” of representation, the representational properties of artefacts.  I will be concerned specifically with linguistic representation: the representational properties of words, sentences and utterances.

Just as my starting point for the metaphysics of belief and desire was David Lewis’s brief brief remarks on (mental) radical interpretation, I will base my story on Lewis’s (much more developed) theory of linguistic representation. In the case of mental representation, the metaphysical story took this form: there is a space of abstract interpretations, which map states or stages of agents to contents. The job of the metaphysician of mental representation is to give an illuminating story about which of these abstract interpretation is correct. And then we “read off” facts about what a person believes or desires, for example: that a person believes that p iff they are in a state which the correct interpretation maps to the ordered pair: <belief,p>. In the case of linguistic representation, the situation is similar. There is a space of abstract interpretations (what Lewis calls “languages”) which map sentences to contents. The job of the metaphysician of linguistic representation is to give an illuminating story about which of these abstract interpretations is correct.

As well as this story, however, one needs to delimit the right space of abstract interpretations. Will the vehicles of linguistic content be individual utterances, utterance-types, sentence-types or individual words? We make this choice when we stipulate the domain of the abstract interpretations that we select between. In the same way, we might target the sentences of an idiolect, or a whole public language.

Framing the problem as involving interpretations that map public language sentence-types to propositions, Lewis offered the following account of correctness.

• The correct interpretation of a set of public sentence-types Z of population P is one that, for each sentence-type S in Z, maps S to p iff there is a conventional regularity within P for someone utter a token of type S only if they believe p (truthfulness), and a conventional regularity for someone to come to believe that p if they hear another utter a token of type S (trust).

The basis on which an interpretation is selected consists of (i) patterns connecting acts of uttering to agent’s beliefs; (ii) the entrenchment of those patterns in communal beliefs and desires—whatever is involved in making a regularity a “convention” within a given population. The appeals to conventions, sentences and populations is something to which we return in a later post. For now, they are working primitives.

People are not always honest, nor always trusting. Some sentences (“I did not do it”) may be more often used dishonestly than honestly. Audiences may rightly fail to trust certain speakers, ask for further evidence. Some sentences might be particularly prone to provoking distrust. Following Lewis, we may appeal to the attitudes of speaker and audience to refine the regularities we are looking for to “serious communicative situations” where the speaker has no interest in deception, and the audience takes the speaker to be an authority. I take such restrictions as read: they will not make regularities exceptionless, but they’ll ensure that generically, they hold.

Some further observations:

1. There are many regularities of truthfulness and trust for any given sentence. I will utter “Harry is a bachelor” only if I believe Harry is unmarried. And someone hearing me utter this will likewise form that belief. Perhaps this regularity will not count as conventions (there are many regularities involved in driving—e.g. driving on the right for the first half of each hour—which are entailed by but not themselves conventions). But prima facie, there are a multitude of candidates for being “the” content conventionally associated with a sentence.
2. Among these, the strongest content conventionally associated with sentences are not necessarily what we think of as what the sentence literally “means”. “He had three drinks and drove home” implies but does not state that the drinking preceded the driving. Speakers will utter this only if they believe in the temporal ordering, and audiences will come to believe the temporal ordering on hearing it. Absent a reason for thinking that only the regularity of truthfulness and trust involving the semantic content is conventional, we should be aware that Lewis’s account doesn’t lock us onto the literal meaning of sentences.
3. Indexical sentences need special attention. A utters “I am sitting” while believing that A is sitting. B utters the same while believing B is sitting. C hearing one or the other utter that sentence, will form one or the other belief—or if the speaker is masked, he might form the descriptive belief “the utterer of that sentence is sitting”. Unless the account is tweaked (e.g. so that regularities of truthfulness and trust relate sentences to functions from contexts to contents, rather than contents directly) then it is not the semantic content, but the “diagonal” content, that figures in regularities of truthfulness and trust.
4. This account is silent on the representational property of units of language below the level of a whole sentence. It is also silent on the representational properties of sentences that are never used, and so feature in no regularities connecting them to states of belief. So the scope of this account is constrained.

So this initial convention-based account leaves us very far from a full or satisfying account of the representational properties of linguistic artefacts. But it is the first staging post towards such an account. Conventionally associated content is the linguistic source intentionality—a layer of representational facts that form the raw materials for an interpretationist story about what ground (literal) meaning of words and more complex expressions.  This interpretationist account is not found directly in the above account of correct sentence-level interpretation (or as Lewis puts it: in the account of what makes an abstract “language” be “in use” by a population). Instead, it is found in his account of what makes something a “grammar” for such a language.

Let us frame the task anew. The space of interpretations now map words of the target public language onto objects (their “semantic values”: that is, the interpretation assigns a reference or denotation to each lexical item). Each now includes a rules that assigns semantic values to more complex sentences (as a special case: sentences). The simplest such rules are compositional, assigning contents to the wholes as a function of the contents already assigned to their parts. Nevertheless, I’ll call a member of this space of abstract interpretations a “compositional interpretation”.

• The correct interpretation of a set of public words W of population P (and the semantic rules for the expressions they form) is the compositional interpretation which best explains the language in use in P.

Here “language in use in P” is just another way of saying “correct interpretation of the public sentence-types of the population”—and is to be explicated as above in terms of conventional regularities of truthfulness and trust.

This move is relevant to each of the four notes above. In the following, I will hold assume that the best explanation of the language-in-use is indeed compositional, and “not” is given its usual meaning.

1. A compositional interpretation of “Harry is a bachelor” won’t assign it the content that Harry is unmarried. For (absent a deviant treatment of “not”) that would ultimately mean it had to assign to “Harry is not a bachelor” the content Harry is not unmarried. But that content doesn’t feature in regularities of truthfulness and trust: speakers are willing to utter the sentence when they believe Harry is unmarried and female.
2. Similar constraints favour the compositional interpretation assigning intuitively “semantic” content over enriched “pragmatic” content.
3. A compositional interpretation can use familiar means to associate indexical sentences both with “diagonal” contents that show up in the conventions, and account for the way that those sentences contribute as parts of larger wholes, delivering an account which has a place both for diagonal and contextually varying, semantic contents for such sentences.
4. Even if the “language in use” just assigns content to those sentences that are actually uttered by members of the population, the compositional interpretation can in principle assign content that goes way beyond this. The correct assignment of referents to words, and compositional rules, are grounded in the properties of the finitely many sentences that are actually in use. But by recombining those words and applying the compositional rules, the compositional interpretation assigns compositional content to sentence-types that have never been uttered.

Lewis’s metaphysics of word-reference, then, has two stages: a sentence-level story that works by linking sentence-types to attitudes (belief) and having the sentences inheriting the content. And the key to understanding this is to understand what makes something a convention. The second stage uses the first like a set of datapoints, and interpolates subsentential content as whatever “best explains” that data. In the story I gave about layers 1 and 2, proper functions grounded source intentionality which grounded the intentionality of belief and desire. In parallel in this story conventions ground raw sentential content which ground word content. Just as radical interpretation appeals to the selectional-ideology of “rationalizing” interpretations of an agent, applied to a base of facts about perceptual and intententional content, Lewis’s metaphysics of word content appeals to the selectional-ideology of “best explanation”, applied to much sparser set of base facts about sentential content.

Our setup defines an agenda.

• Say something about the selectional ideology of “best explanation”.
• Say something about the base facts that fix sentential content: conventions of truthfulness and trust.
• Say something about the how facts about words and populations factor into this story.

With the core of this approach to language on the table, we can move to more advanced themes.

• Varying assumptions about the content inherited from belief.
• Varying assumptions about the attitude conventionally linked to sentences.
• Varying assumptions about the relative priority of thought and language.