NoR 4.5: the base–words, population, convention.

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. 

Previous posts in this subsequence have taken convention as basic, and worked forward from that to an account of languages in use, correct compositional interpretation, attitude expressed, and the like. In this post, I’m going to outline the account of base facts, to hook this account of layer-3 representational facts back in to the facts about mental representation established at layer-2. I’ll also sketch how (in joint work with Gail Leckie) we have proposed extending this account to give a treatment of some other elements of the “base” for selecting the correct linguistic interpretation: the words that are interpreted, and the language-using population.

Lewis’s account of convention was as follows. A regularity R is a convention in a population P iff within P, the following hold, with at most a few exceptions:

1. Everyone in P conforms to R.
2. Everyone in P believes that everyone in P conforms to R.
3. This belief gives everyone in P a good reason to conform to R himself.
4. There is a general preference in P for general conformity to R rather than slightly-less-than-general conformity to R
5. There is an alternative possible regularity R’ such that if it met (1) and (2), it would also meet (3) and (4)
6. All of (1-5) are common knowledge.

The relevant regularities, generalized to allow for states of acceptance of enriched content, are the following:

• (Truthfulness) Members of P utter s only if they accept p, where L(s)=p.
• (Trust) If a member of P hears another member of P utter s, she tends to come to accept p, where L(s)=p.

And so what naturally suggests itself is the following account the linguistic “source intentionality”, the language-in-use appealed to in our previous discussions:

• (Lewis) Given an exogenously fixed specification of population P1 and typing of sentences, T1, L is the language of P1 for T1 iff there are conventions of (Truthfulness) and (Trust) in L in P1 for T1

Let me note some features of this. First, the characterization of convention is full of appeals to attitudes of members of the population: their beliefs and preferences, together with normative facts about reasons for conforming to a regularity. Together with Truthfulness and Trust and the way that they appeal to psychological facts about agents, clearly the work done to ground belief/desire and other facts about mental representation are being drawn on heavily at this point.

I am not going to engage in detail with the various worries one might have about this account of convention, or the modifications one might introduce to evade it. It doesn’t really matter to me whether this is a good account of convention in general, so long as it’s a good characterization of the features of regularities in language use that feed into linguistic source intentionality. And any other characterization of convention that appealed to intentional resources and delivered the same results on our target cases would do just as well, at least to this point. But just as my previous handling of mental source intentionality, my interest will be on extending the scope of the appeals to convention.

The need for extension is prompted by the appeal, in the account as currently formulated, for exogeneous typing of sentences and identification of language-using populations. But we don’t get facts about sentence-types of language using populations for free. But what grounds facts concerning when two blasts of sound are of the same sentence type, or when two people belong to a single language-using population? As is familiar in the specialist literature on this, it’s extremely implausible that we have any way to identify sentence-types by types of shapes or sounds (for an excellent review of problem cases and the relevant literature, Nick Tasker’s PhD thesis and papers should be a first port of call). The worry is that there’s no way to pick out sentence-types independently of semantic facts. What other than semantic facts makes ambiguous homophones/homographs “bank” and “bank” distinct words? It is no easier to imagine independent way of picking out a population that uses a single language, except by the fact that they are all users of that very language. But of course, the latter is a semantic fact that could not feature in a exogeneous characterization of populations (I’m grateful to Leeds’ Roger White for alerting me to that to several years ago).

Leckie and I suggest a different model:

• (Endogenous) Given an utterance u, <P, T, L> is a language in use in utterance u iff P is a population and T a typing relation relative to which there are conventions of (Truthfulness) and (Trust) in L, and the speaker/hearer of u is a member of the population P; and u is a member of some equivalence class of the typing relation T.

Instead of determining L after fixing a particular population and typing relation, (Endogenous) treats the population and typing relation as variables whose values are fixed however is necessary to produce conventions of (Truthfulness) and (Trust). The correct word typing for English is as described by the T role in a language-in-use for a population that includes the utterance I am presently making. The membership of the language-using population of which I am a part is as described by the P-role in that same language-in-use. And finally, the content-sentence pairings that constitute linguistic source intentionality for English can be read off that same triple.

It is important to understand that endorsing this account does not foreclose saying other, more immediately illuminating things about words and populations. If you thought you had an exogeneous way of specifying a language-using population and a typing relation that feature in linguistic conventions, then all the better for (Endogeneous)—that typing relation and population will be an illuminating independent specification of a typing relation that features in a language-in-use, according to our formulation. But of course, pessimism on that front motivated the shift to this one. But it’s much more plausible is that one could, via appeal to semantic facts, give a more illuminating characterization of the language-using population and a typing relation. For example, Nick Tasker’s PhD dissertation an intriguing account of the nature of words is offered, building on work in the metaphysics of artefacts by Amie Thomasson. An account of word-individuation (or at least, various necessary and sufficient conditions) is offered as part of the package, built on the more general model of individuation of artefact-kinds. But Tasker is clear from the start that among the determinants of word-individuation for him are facts about the semantic properties of the individual word tokens, their recognizability to a certain audience, and so forth. Tasker’s account might be exactly what we need to understand how words work, but also entirely unsuitable to be slotted in as an “exogeneous” account of word-individuation as per the original model. But so long as word-types as he characterizes them figure in linguistic conventions, his account is consistent with (Endogenous).

In sum: since the reductive characterization of words and populations is given by (Endogenous) and not by an exogenous characterization, the project of saying interesting things about types and populations that figure in languages in use doesn’t have to be burdened by any reductive constraint. Metaphysically speaking, the bounds of the population, the relevant types, and the contents conventionally associated with sentences, are all jointly and simultaneously grounded in facts about patterns of linguistic usage and attitudes of speakers and hearers.

The worry about this kind of account is not that it’ll fail to count genuine sentences and language-using populations as sentences and populations. The worry to have is that it will overgenerate. After all, by choosing crazy typing relations and gerrymandered populations, we may be able to find all sorts of dubious regularities connecting uses of sentences (so typed) to attitudes. In the Leckie/Williams paper, we consider a number of different ways this might happen, for example, by subdividing genuine populations and types (typing utterances by brown-eyed people separately from blue-eyed people); merging separate types together, or tailoring the population or typing so as to bias the resulting regularity (e.g. by restricting it to population who apply “red” to more orangey things than is the norm). Our strategy in response is to work through such examples, and argue that none of them produces a genuine example of overgeneration. They are gerrymandered regularities of truthfulness and trust, sure—but we argue, they each violate one or more clauses of the characterization of convention Lewis gave.

Suppose the Leckie/Williams project succeeds. Then revised characterization of “language in use” means that we remove the need to list in addition the typing of sentences and the identification of populations as among our the base facts of the metaphysics of linguistic representation. And with that, the last tie between the layers of representation has been put in place.