See main: Nature abhors a vacuumParmenides' famous "denial of the void" erupted into what would become a 2,000-year heated and intricate debate, with views going back and forth on the matter, as to whether or not voids or vacuums can or cannot or do or do not exist. The first to object to Parmenides' denial was Leucippus who invented the now-famous atomic theory, which was stimulated into conception to purposely contradict Parmenides; the short version of Leucippus' theory being that the postulate that everything in the universe is either atoms or voids.
“Could empty space exist, and is heavenly space unbounded?”
|A Schott diagram depiction of German engineer Otto Guericke's famous circa 1649 beer keg vacuum experiment, in which Guericke and another man (or Guericke's two assistants) try to completely evacuate the air form a well-caulked beer keg, so to see if a "vacuum" could be made, the existence of which that was deemed impossible by Parmenides.|
“Parmenides’ theory may be described as the first hypothetico-deductive theory of the world. The atomists took it as such; and they asserted that it was refined by experience, since motion does exist. Accepting the formal validity of Parmenides’ argument, they inferred from the falsity of his conclusion the falsity of his premise. But this meant that the nothing — the void, or empty space — existed. Consequently, there was now no need to assume that ‘what is’ — the full, that which fills some space — had no parts; for its parts could now be separated by the void.”— Karl Popper (1958), “Back to the Presocratics” 
“Being is unbegotten, indestructible, whole, eternally one, immovable and infinite. With it there is no was nor shall be; the whole is forever now, one and continuous.”— Parmenides (c.460BC), Publication; cited by: Henry Bray (1910)