That is how the scientific method works. Falsify the proposition. If any single point is demonstrated to be false then the entire edifice is false.
Prove that claim.
If that was indeed the case, there goes relativity. Because "you can't eat your cake and have it too." You cannot assume a theory which is based on the visual behavior of objects traveling light-speed, when you state that such a feat is impossible, and especially when such objects would be invisible (for one, if they travel
300,000 meters every 0.013sec) and the outcome of such an impossible happening uncertain.
I could be philosophical and say, "well as I have repeatedly stated, you can't have something out of nothing and therefore you can't have a perforated Infinite, let alone space", but that may be too deep a concept for some to wrap their brains around.
How many things we accept in physics axiomatically, without proof to make our calculations and theories fit? Many.
Here is one: according to Newtonian physics since a photon has no mass, gravity would not affect it, yet near a black hole, Newton's theory doesn't apply, and relativity takes over. Also while a photon does not have mass, it does have relativistic mass and gains momentum can indent matter etc.;
E=mc^2-> c = sq. root (E/*m*)-> if m=0 then c is zero. So for convention or rather convenience we say photon does not have mass, it has relativistic mass. With other words "have your cake and eat it too."
But, you asked for a proof, even though you are content with all the other axioms and conventions taken by scientists and physicists. Well here it is even though I don't need to provide one, since the person offering the counter to my argument, has to also provide proof that there is such thing as "absolute void":
If the photon has no mass ( or "relativistic"/ too small to count, or care to count), then the only reason it would be affected by the gravitational forces of a black hole, is because the space (the infinitesimally minute particles that comprise the fabric of space) through which light traverses is also affected, pulled by gravitational forces, and the "massless" photons are pulled along simply because their movement is dependent upon the particles that comprise what you deam as void (the particles pass on photons as if through a wavy motion). If we say that the gravitatinal force of a black hole is simply too large for light to avoid, then by G = (Mxm)/r^2, setting m = 0, light should have no problem crusing through at a straight line with speed = C, because then G force on light would also be "0" or minute (relativisticly small). But that is not what happens, is it?
Regardless whether the photon has mass or not (relativistic or otherwise, and relativistic would mean too small to measure and therefore we call it "zero."), the photons could not have acquired the energy to travel without it being somehow replenished; the photons would need something to pass them along, even through what you call "vacuum" or void. The fact that light travels through void, is proof enough that absolute void does not exist. The fact that the oldest and longest galaxy we can see, is 32 billion light years away, is proof that light does not loose kinetic energy, which means something provides it by moving it along, even through the void. That is why absolute void cannot, exist, because if it did, the aforementioned galaxy GN-Z11 would have been lost in oblivion; since even if the "massless", or "relativistically massed" photons have gained enough momentum to jump through gaps of void (that being the case their would not be a wavelength at some point and perhaps even the direction of light would change), at some point something still would need to drive them on. How did light found its way, through 32 billion years of "vacuum" for us to see it, when the momentum of light would be P= (->0) x c which means the tangent line of the momentum of light would be approaching "0" value (light would have no momentum despite its speed of 300,000,000 m/s).
So simply put, the proof that there is no such thing as absolut void, is that light traverces through it, because particles, however minute, pass it along in a wavy motion at a speed of C.
Here is a link from wikipedia (now yhat I can provide them):
https://en.m.wikipedia.org/wiki/Vacuum
From wikipedia:
"According to modern understanding, even if all matter could be removed from a volume, it would still not be "empty" due to vacuum fluctuations, dark energy, transiting gamma rays, cosmic rays, neutrinos, and other phenomena in quantum physics. In the study of electromagnetism in the 19th century, vacuum was thought to be filled with a medium called aether. In modern particle physics, the vacuum state is considered the ground state of a field."
In order to achieve absolute vacuum in the lab, we need to install a small blackhole at yhe edge of the chamber which is to be containing it.