Full Idea
The standard conception of worlds incorporates the assumption of bivalence - every proposition is either true or false. But it is infelicitous to build into one's basic semantic machinery a principle endorsing classical logic against its rivals.
Gist of Idea
Possible worlds make every proposition true or false, which endorses classical logic
Source
Bob Hale (Necessary Beings [2013], 10.3)
Book Reference
Hale,Bob: 'Necessary Beings' [OUP 2013], p.227
A Reaction
No wonder Dummett (with his intuitionist logic) immediately spurned possible worlds. This objection must be central to many recent thinkers who have begun to doubt possible worlds. I heard Kit Fine say 'always kick possible worlds where you can'.