Since this last was the original inspiration for this paper and we make partial use of it I shall outline it briefly. Perez-Laraudogoitia also created the Beautiful Supertask within a Newtonian universe. Yet how can mere increase in speed result in non-existence? Perez Laraudogoitia ( 1997) has shown how this can be modelled in a Newtonian universe by arranging an infinitude of particles to successively collide with a single particle, doubling its speed on each collision. Where has it got to one hour after it started? Infinitely far from its starting place? But there is no such place. Footnote 6 So, for example, consider Benardete’s Spaceship Paradox ( 1964), in which a space ship doubles its speed in the first ½ hour, doubles it again in the next ¼ hour and so on. Supertasks can be set up in Newtonian universes of point particles with classical dynamics (hereafter, Newtonian universes) in which actual infinities of particles are permitted but each must have a finite speed. Yet how could they cause him to stay still without causally interacting with him? Only a wall can stop him and no wall is ever raised, since for each wall he must reach it for it to be raised but he would have been stopped at an earlier wall.

The gods have kept him still without ever raising a wall. Since for any place after A, a wall would have stopped him reaching it, the traveller cannot move from A. A second god (unknown to the first) waits in readiness to throw up a wall of his own blocking the man’s further advance when the man has travelled ¼ mile.

A god waits in readiness to throw up a wall blocking the man’s further advance when the man has travelled ½ a mile. A man decides to walk one mile from A to B.

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