Full Idea
Mathematics seems necessary because the real contents of mathematical statements are logical truths, which are necessary, and it seems a priori because logical truths really are a priori.
Gist of Idea
Mathematics is both necessary and a priori because it really consists of logical truths
Source
Stephen Yablo (Abstract Objects: a Case Study [2002], 10)
Book Reference
-: 'Nous' [-], p.237
A Reaction
Yablo says his logicism has a Kantian strain, because numbers and sets 'inscribed on our spectacles', but he takes a different view (in the present Idea) from Kant about where the necessity resides. Personally I am tempted by an a posteriori necessity.