Full Idea
If experience shows that some aspect of the physical world fails to instantiate a certain mathematical structure, one will modify the theory by sustituting a different structure, while the original structure doesn't lose its status as part of mathematics.
Gist of Idea
If a mathematical structure is rejected from a physical theory, it retains its mathematical status
Source
Charles Parsons (Review of Tait 'Provenance of Pure Reason' [2009], §2)
Book Reference
-: 'Philosophia Mathematica' [-], p.224
A Reaction
This seems to be a beautifully simple and powerful objection to the Quinean idea that mathematics somehow only gets its authority from physics. It looked like a daft view to begin with, of course.