Full Idea
If a ship moves forward and a man carries a rod backwards on it, then it is possible for an object to move without quitting its place.
Gist of Idea
A man walking backwards on a forwards-moving ship is moving in a fixed place
Source
Sextus Empiricus (Against the Physicists (two books) [c.180], II.056)
Book Reference
Sextus Empiricus: 'Against the Physicists/Against the Ethicists', ed/tr. Bury,R.G. [Harvard Loeb 1997], p.239
A Reaction
[summary of a verbose paragraph] The point is that you cannot define movement as change of place (contrary to Russell's proposal!). The concept of a place seems to be relative. Walking on a treadmill.
Related Idea
Idea 14168 Occupying a place and change are prior to motion, so motion is just occupying places at continuous times [Russell]