Full Idea
Where Kant and others had traditionally assumed that the a priori concerned beliefs 'justifiable independently of experience', Quine and others of the time came to regard it as beliefs 'unrevisable in the light of experience'.
Gist of Idea
The traditional a priori is justified without experience; post-Quine it became unrevisable by experience
Source
Georges Rey (The Analytic/Synthetic Distinction [2013], 3.7)
Book Reference
'Stanford Online Encyclopaedia of Philosophy', ed/tr. Stanford University [plato.stanford.edu], p.9
A Reaction
That throws a rather striking light on Quine's project. Of course, if the a priori is also necessary, then it has to be unrevisable. But is a bachelor necessarily an unmarried man? It is not necessary that 'bachelor' has a fixed meaning.