Note 99 — Chapter IV

That is, we do not consider the sophism of Zeno refuted by the fact that the geometrical progression a(1 + 1/n + 1/n2 + 1/n3 +,... etc.)—in which a designates the initial distance between Achilles and the tortoise, and n the relation of their respective velocities—has a finite sum if n is greater than 1. On this point we may refer to the arguments of F. Evellin, which we regard as conclusive (see Evellin, Infini et quantité, Paris, 1880, pp. 63-97; cf. Revue philosophique, vol. xi., 1881, pp. 564-568). The truth is that mathematics, as we have tried to show in a former work, deals and can deal only with lengths. It has therefore had to seek devices, first, to transfer to the movement, which is not a length, the divisibility of the line passed over, and then to reconcile with experience the idea (contrary to experience and full of absurdities) of a movement that is a length, that is, of a movement placed upon its trajectory and arbitrarily decomposable like it.