Full Idea
If logic and mathematics being true by convention says the primitives can be conventionally described, that works for anything, and is empty; if the conventions are only for those fields, that's uninteresting; if a general practice, that is false.
Gist of Idea
Claims that logic and mathematics are conventional are either empty, uninteresting, or false
Source
Willard Quine (Truth by Convention [1935], p.102)
Book Reference
Quine,Willard: 'Ways of Paradox and other essays' [Harvard 1976], p.102
A Reaction
This is Quine's famous denial of the traditional platonist view, and the new Wittgensteinian conventional view, preparing the ground for a more naturalistic and empirical view. I feel more sympathy with Quine than with the other two.