Full Idea
If the alleged necessity, e,g, 2+2=4, really does depend upon a convention governing the use of the words in which we state it, and the existence of that convention is merely a contingent matter, then it can't after all be necessary.
Gist of Idea
If necessity rests on linguistic conventions, those are contingent, so there is no necessity
Source
Bob Hale (The Source of Necessity [2002], p.302)
Book Reference
-: 'Philosophical Perspectives' [-], p.302
A Reaction
[Hale is citing Blackburn for this claim] Hale suggests replies, by keeping truth and meaning separate, and involving laws of logic. Blackburn clearly has a good point.