If Space is empty then while defining Coulomb's law in vacuum why do we even mention about permittivity $\varepsilon _{0}$ of free space? [duplicate]

In physics, Coulomb’s Law calculates the electrical force between two charges. Inside this formula, there is a strict requirement for a constant called ( $\varepsilon _{0}$ ) (epsilon naught), which represents the 'permittivity of free space'. Essentially, this constant measures how much 'empty space' resists or allows an electric field to pass through it.Here is the paradox: We are taught that the vacuum of outer space is absolute nothingness—it is completely devoid of matter, air, and atoms.If space is truly empty 'nothingness,' how can it have a measurable physical property ( $\varepsilon _{0}$ )? For an electric field to interact with something, or for a medium to 'permit' a force, shouldn't there be something physical there to do the interacting? Does the existence of ( $\varepsilon _{0}$ ) prove that 'nothingness' is actually an active, physical medium?"