Full Idea
It has been observed that Frege has a motive to treat numbers as objects, but not a justification for doing so.
Gist of Idea
Frege had a motive to treat numbers as objects, but not a justification
Source
comment on Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884]) by B Hale / C Wright - Intro to 'The Reason's Proper Study' §3.2
Book Reference
Hale,B/Wright,C: 'The Reason's Proper Study' [OUP 2003], p.7