Full Idea
Combinatorial theories of possibility take it for granted ....that possible worlds in general share a syntax, as it were, differing only in the constituents from which they are generated, or in the particular manner of their arrangements.
Gist of Idea
Combinatorial theories of possibility assume the principles of combination don't change across worlds
Source
Gideon Rosen (The Limits of Contingency [2006], 08)
Book Reference
'Identity and Modality', ed/tr. MacBride,Fraser [OUP 2006], p.36
A Reaction
For instance, it might assume that every world has 'objects', to which 'properties' and 'relations' can be attached, or to which 'functions' can apply.