Lewis, "Languages and Language"

Brief Comments

Curtis Brown

• Lewis's "Languages and Language" as a way of connecting intensional truth-condition theories (which regard a language as an abstract object that we can discuss using set-theoretical apparatus) with Gricean theories of languages as social practices.
• The connection, as Lewis sees it: a language (in the abstract sense) is used by a population if and only if there is a convention of truthfulness and trust in the language in that population. (Truthfulness in a language means attempting, by and large, to utter only sentences to which the language assigns, as intensions, a function whose value at the world of the utterance is "True." Trust in a language means that when you hear someone else make an utterance, you believe (by and large) the intension that the language assigns to the sentence.)
• So: for a population P to use a language L is for there to be, in P, a convention of truthfulness and trust in L. But what is a convention? In short, "Conventions are regularities in action, or in action and belief, which are arbitrary but perpetuate themselves because they serve some sort of common interest" (p. 164). In more detail:

1. There is a regularity R of the appropriate kind in P. (In our case, a regularity of truthfulness and trust in L.)
2. Everyone believes that everyone else acts in accordance with the regularity.
3. There is a general preference for general conformity to R.
4. The fact that this regularity obtains gives individuals a reason (in conjunction with their other goals) to continue acting in accordance with the regularity.
5. There are other possible regularities that could in principle work as well as the actual one, if they were followed as widely.
6. All the above facts are "common knowledge," in the sense that everyone knows them, and everyone knows that everyone knows them, etc.