Full Idea
For Frege, syntactic categories are prior to ontological ones, and it is by reference to the syntactic structure of true statements that ontological questions are to be understood and settled.
Gist of Idea
For Frege, ontological questions are to be settled by reference to syntactic structures
Source
report of Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884]) by Crispin Wright - Frege's Concept of Numbers as Objects 1.v
Book Reference
Wright,Crispin: 'Frege's Conception of Numbers' [Scots Philosophical Monographs 1983], p.25