Full Idea
Frege gave up on the attempt to introduce natural numbers by contextual definition, but the project has been revived by neo-logicists.
Gist of Idea
The attempt to define numbers by contextual definition has been revived
Source
report of Crispin Wright (Frege's Concept of Numbers as Objects [1983]) by Kit Fine - The Limits of Abstraction II
Book Reference
Fine,Kit: 'The Limits of Abstraction' [OUP 2008], p.55