One of the main controversies in Pre-socratic philosophy is the dispute of the existence or non-existence of the void. Two groups of philosophers argue this idea. The first group, namely Parmenides, argues that the void does not exist. This is the opinion of the Monist philosophers. The other group is the atomists who argue this thesis and believe there is a void. This group is primarily represented by the philosophers, Democritus and Leucippus.
Parmenides argues against the existence of the void. The plenum fragment states his opinion quite clearly:
"Nor is it divisible, since it is all alike; nor is there more here and less there, which would prevent it from holding together, but it is full of what is. So it is all continuous, for what is clings close to what is."
This shows the idea, that if there would be a void or an empty space then "what is" would move into it. Hence, there is no void. Because "what is" fills up this space completely. "Since it is all alike" volume or density is continuous everywhere. Since it is not divisible there is no void between "what is". Also "what is" itself has no void in it. If there were void or space in one object, compared to a more denser object these particles would not "hold together". These densities are balanced out. Therefore, density in "what is" is continuous. Furthermore "what is"
does not move from one place to the other. Since "what is" clings together, there is no empty space an object could move to. Therefore, movement is impossible. "Moreover it is immovable, held so in mighty bonds. And it is without beginning and end, because both creation and destruction have been driven away by true belief. Remaining always the same and in the same place by itself, it stays fixed where it is" (Fragment 7 C, page 98). Here Parmenides includes his idea of a plenum, where "what is" remains the same and is either created nor destroyed. This further proves the point that...