"For science, the invention of the differential calculus was a giant step. For the first time in human history the concept of the infinite, which had intrigued philosophers and poets from time immemorial, was given a precise mathematical definition, which opened countless new possibilities for the analysis of natural phenomena. ...According to Zeno, the great athlete Achilles can never catch up with a tortoise... The flaw in Zeno's argument lies in the fact that even though it will take Achilles an infinite number of [procedural] steps to reach the tortoise, this does not take an infinite time. With the tools of Newton's calculus it is easy to show that a moving body will run through an infinite number of infinitely small intervals in a finite time."