Full Idea
One geometry cannot be more true than another; it can only be more convenient.
Gist of Idea
One geometry cannot be more true than another
Source
Henri Poincaré (Science and Method [1908], p.65), quoted by Stewart Shapiro - Philosophy of Mathematics
Book Reference
Shapiro,Stewart: 'Philosophy of Mathematics:structure and ontology' [OUP 1997], p.154
A Reaction
This is the culminating view after new geometries were developed by tinkering with Euclid's parallels postulate.