Full Idea
A novel describes a possible world in as much detail as is possible without exceeding the resources of the agent's language. But if talk of possible worlds seems dangerously metaphysical, focus on the novels themselves, when complete and consistent.
Gist of Idea
A possible world can be seen as a complete and consistent novel
Source
Richard Jeffrey (The Logic of Decision [1965], 12.8), quoted by David Lewis - On the Plurality of Worlds
Book Reference
Lewis,David: 'On the Plurality of Worlds' [Blackwell 2001], p.142
A Reaction
Lewis seems to cite this remark from Jeffrey as the source of the idea that ersatz linguistic worlds are like novels. Why won't a novel with one tiny inconsistency count as a possible world? People seem to live in it.
Related Idea
Idea 16284 Ersatz worlds represent either through language, or by models, or magically [Lewis]