One of Zeno’s paradoxes which relate to the issue of whether time and space are made up of minute indivisible parts. It considers two rows of objects of equal size—of the smallest possible size—moving with equal velocity in opposite directions, with a speed equal to the smallest unit of length per smallest unit of time. The argument at the centre of the paradox is that relative to one another, they move at one unit of space in half of the unit of time, contradicting the proposition that there is a smallest unit of time.