Rene Descartes invented the famous Cartesian coordinate system.He worked in the field of analytic geometry.

Rene desscartes was the father of mathematics.

== == Oddly enough, the place now called Descartes. Initially called La Haye en Touraine, the town was renamed La Haye-Descartes in 1802 in his honour, and then renamed again to Descartes in 1967.

Modern science also uses a clear method to discover answers to questions. (Apex)

Short answer: Descartes' doubt was like WWI - the doubt to end all doubt. Only by doubting everything could Descartes hope to find anything that was certain (even if the only certainty is that nothing else is certain!).