Full Idea
In our search for the direct road towards truth we should busy ourselves with no object about which we cannot attain a certitude equal to that of the demonstrations of Arithmetic and Geometry.
Gist of Idea
In pursuing truth, anything less certain than mathematics is a waste of time
Source
René Descartes (Rules for the Direction of the Mind [1628], Rule II), quoted by Alain Badiou - Mathematics and Philosophy: grand and little p.8
Book Reference
Badiou,Alain: 'Theoretical Writings' [Continuum 2006], p.8
A Reaction
A beautiful statement of the way in which rationalist philosophy was founded on the model of mathematics (esp. Euclid), with all its concomitant problems. The most important concept of the last hundred years may well be fallibilist rationalism.