Full Idea
Frege urges us to regard properties as just a special kind of function, and in the case of numerical properties he comes close to identifying a property with its characteristic function.
Gist of Idea
Frege treats properties as a kind of function, and maybe a property is its characteristic function
Source
report of Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884]) by Peter Smith - Intro to Gödel's Theorems 11.3 n 5
Book Reference
Smith,Peter: 'An Introduction to Gödel's Theorems' [CUP 2007], p.87
A Reaction
Every now and then really interesting bits of metaphysics pop out of Frege, though it usually needs commentators to show the implications. Does the 'characteristic' imply a teleological view?