The unproved postulates with which we start are purely arbitrary. They must be consistent, but they had better lead to something interesting.
Quoted in D MacHale, Comic Sections (Dublin 1993)
The present author confesses that, to him, geometry is nothing at all, if not a branch of art ...
A Treatise on Algebraic Plane Curves
The URL of this page is:
http://www-history.mcs.st-andrews.ac.uk/Quotations/Coolidge.html