Full Idea
There is no axiom system for mathematics, geometry, and so forth that does not presuppose set theory.
Gist of Idea
All the axioms for mathematics presuppose set theory
Source
John von Neumann (An Axiomatization of Set Theory [1925]), quoted by Stewart Shapiro - Foundations without Foundationalism 8.2
Book Reference
Shapiro,Stewart: 'Foundations without Foundationalism' [OUP 1991], p.209
A Reaction
Von Neumann was doubting whether set theory could have axioms, and hence the whole project is doomed, and we face relativism about such things. His ally was Skolem in this.