How do we speak of what is not there?
For the ancient Greeks, the very question was a paradox. In a sun-drenched agora, the philosopher Parmenides declared that to even mention "nothing" was to grant it a forbidden existence. He saw the universe as a plenum—a space entirely filled, with no room for absence. Nature, they argued, abhorred a vacuum. This fear of the void, this *horror vacui*, was...
