Mr William Charlton (Philosophy 56, No. 216 (April 1981)) quotes Russell on Motion. It has been pointed out to me that the book referred to in line 5 as Principles of Philosophy should in all probability be The Principles of Mathematics, and on looking into the matter I find that this is indeed the case. On p. 473 of the latter book I read: 447. It is to be observed that … we must entirely reject the notion of a state of motion. Motion consists merely in the occupation of different places at different times, subject to continuity as explained in Part V.