Full Idea
For Frege the variable ranges over all objects.
Gist of Idea
For Frege the variable ranges over all objects
Source
report of Gottlob Frege (Begriffsschrift [1879]) by William W. Tait - Frege versus Cantor and Dedekind XII
Book Reference
'Philosophy of Mathematics: anthology', ed/tr. Jacquette,Dale [Blackwell 2002], p.59
A Reaction
The point is that Frege had not yet seen the necessity to define the domain of quantification, and this leads him into various difficulties.