Starting in the seventeenth century, the general theory of extreme values - maxima and minima - has become one of the systematic integrating principles of science.
Richard CourantFor scholars and laymen alike it is not philosophy but active experience in mathematics itself that can alone answer the question: What is mathematics?
Richard CourantWith an absurd oversimplification, the 'invention' of the calculus is sometimes ascribed to two men, Newton and Leibniz. In reality, the calculus is the product of a long evolution that was neither initiated nor terminated by Newton and Leibniz, but in which both played a decisive part.
Richard Courant