Full Idea
There is no reason to suppose that any statement that is logically necessary (in the present sense) is knowable a priori. ..If a statement is logically necessary, its negation will yield a contradiction, but that does not imply that someone could know it.
Gist of Idea
A logically necessary statement need not be a priori, as it could be unknowable
Source
Ian Rumfitt (Logical Necessity [2010], §2)
Book Reference
'Modality', ed/tr. Hale,B/Hoffman,A [OUP 2010], p.44
A Reaction
This remark is aimed at Dorothy Edgington, who holds the opposite view. Rumfitt largely defends McFetridge's view (q.v.).