Full Idea
Frege challenged synthetic a priori truths by expanding the concept of analyticity, undertaken in order to provide a semantic basis for his logicist explanation of mathematical truth as analytic truth.
Gist of Idea
Frege tried to explain synthetic a priori truths by expanding the concept of analyticity
Source
report of Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884]) by Jerrold J. Katz - Realistic Rationalism Int.xx
Book Reference
Katz,Jerrold J.: 'Realistic Rationalism' [MIT 2000], p.-15