 Zeno, at least as portrayed in Aristotle’s Physics, argued that as a consequence, motion does not exist. Since an infinite number of steps cannot be completed, Achilles will never reach the finish line (or never have started in the regressive version). However, modern mathematics provides ways of explaining how Achilles can complete this supertask. As Salmon (1998) has pointed out, much of the mystery of Zeno’s walk is dissolved given the modern definition of a limit. This provides a precise sense in which the following sum converges: