Full Idea
It is objected to 2D semantics that it cannot explain Kripke's cases of contingent apriori truths, for there is no single proposition (construed as a set of possible worlds) that is both apriori and contingent.
Gist of Idea
2D semantics can't respond to contingent apriori claims, since there is no single proposition involved
Source
Laura Schroeter (Two-Dimensional Semantics [2010], 2.4.2)
Book Reference
'Stanford Online Encyclopaedia of Philosophy', ed/tr. Stanford University [plato.stanford.edu], p.34
A Reaction
This sounds like a rather large objection to the whole 2D plan, if it implies that when we say something there is no single proposition that is being expressed.
Related Idea
Idea 13962 Two-dimensional semantics gives a 'primary' and 'secondary' proposition for each statement [Chalmers]