Full Idea
The possible worlds construal affords an elegant algebra of meaning by way of set theory: e.g. entailment between sentences is just the subset relation - S1 entails S2 if S2 is true in any world in which S1 is true.
Gist of Idea
Possible worlds explain aspects of meaning neatly - entailment, for example, is the subset relation
Source
William Lycan (Philosophy of Language [2000], Ch.10)
Book Reference
Lycan,William G.: 'Philosophy of Language' [Routledge 2000], p.153
A Reaction
We might want to separate the meanings of sentences from their entailments (though Brandom links them, see Idea 7765).
Related Idea
Idea 7765 The use of a sentence is its commitments and entitlements [Brandom, by Lycan]