Full Idea
The arithmetical instances of undecidability that arise at one stage of the hierarchy are settled at the next.
Gist of Idea
Arithmetical undecidability is always settled at the next stage up
Source
Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4)
Book Reference
-: 'Philosophia Mathematica' [-], p.10