Full Idea
The reductionist view of propositions sees them as either extensional functions from possible worlds to truth values, or as ordered sets of properties, relations, and perhaps particulars.
Gist of Idea
Propositions might be reduced to functions (worlds to truth values), or ordered sets of properties and relations
Source
George Bealer (Propositions [1998], §1)
Book Reference
'Philosophy of Logic: an anthology', ed/tr. Jacquette,Dale [Blackwell 2002], p.121
A Reaction
The usual problem of all functional accounts is 'what is it about x that enables it to have that function?' And if they are sets, where does the ordering come in? A proposition isn't just a list of items in some particular order. Both wrong.