in which the atoms move around, in other words, vacuum or void. Here, the atomists were reacting to Melissus’ argument that motion is impossible: for something to move it must move into an empty place, but an empty place is nothing, and there is no such thing as nothing. The atomists hijack Melissus’ train of thought and drive it in the other direction. Since we can plainly see that motion is possible, there must be such a thing as nothingness, in which things are moving (§545). This nothingness is the void.
