Full Idea
If P is metaphysically necessary, then it is absolutely necessary, and necessary in every real (non-epistemic) sense; and if P is possible in any sense, then it's possible in the metaphysical sense.
Gist of Idea
Metaphysical necessity is absolute and universal; metaphysical possibility is very tolerant
Source
Gideon Rosen (The Limits of Contingency [2006], 02)
Book Reference
'Identity and Modality', ed/tr. MacBride,Fraser [OUP 2006], p.16
A Reaction
Rosen's shot at defining metaphysical necessity and possibility, and it looks pretty good to me. In my terms (drawing from Kit Fine) it is what is necessitated or permitted 'by everything'. So if it is necessitated by logic or nature, that's included.