 There can be little doubt that Poincaré, with his much greater command of mathematics, won much of the debate, as Russell, with his characteristic willingness to admit his errors, was willing to concede. But a significant difference of approach between them was never to be resolved. Poincaré’s analysis began with rigid bodies and their motions, from which a concept of distance is created. Russell argued on the contrary, that whatever we may discover the concept of distance to be, we know before we begin that the distance from London to Paris is more than a metre. This Poincaré denied in his “Des fondements de la géométrie: à propos d’un livre de M. Russell” (1899).