Full Idea
If you want a logic of metaphysical possibility, the existing literature was originally developed to supply a logic of metalogical possibility, and still reflects its origins.
Gist of Idea
Modal logic gives an account of metalogical possibility, not metaphysical possibility
Source
JP Burgess / G Rosen (A Subject with No Object [1997], II.B.3.b)
Book Reference
Burgess,J/Rosen,G: 'A Subject with No Object' [OUP 1997], p.141
A Reaction
This is a warning shot (which I don't fully understand) to people like me, who were beginning to think they could fill their ontology with possibilia, which could then be incorporated into the wider account of logical thinking. Ah well...