The French philosopher was Descartes. He extolled reason as the criterion of truth and rationality as the standard by which everything was to be judged. Descartes was a brilliant mathematician whose inspiration came from Euclidean geometry which enabled complex structures to be built up from simple axioms. The nature of geometry is that there is only one right answer to a problem. All other answers are false. 
2 5 2
those were led by Denis Diderot (1713 – 1784) and Jean le Rond d'Alembert (1717 – 1783)
thank you
will you help me in one more question posted by me