Full Idea
(In creating the concept of direction..) We carve up the content in a way different from the original way, and this yields us a new concept. ...It is a matter of drawing boundary lines that were not previously given.
Gist of Idea
We create new abstract concepts by carving up the content in a different way
Source
Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884], §64)
Book Reference
Frege,Gottlob: 'The Foundations of Arithmetic (Austin)', ed/tr. Austin,J.L. [Blackwell 1980], p.75
A Reaction
[second half in §88] 'Recarving' is now the useful shorthand for Frege's way of creating abstract concepts (rather than the old psychological way of ignoring some features of an object).