By the “theory” we were educated:
“ if we cannot observe physical phenomenon then it doesn't exist.
We can ignore this phenomenon. “
Today the situation is : there are two fundamental constants in nature:
T=0K and constant speed of photon: c-1.
We cannot reach constant speed of photon c=1 but photon can
and ( thanks to Michelson ) it was observed and therefore it was accepted.
We cannot reach T=0K, we cannot straight observe phenomena in T=0K.
Any instrument does not fit. But can this mean that this continuum is abstract ?
The “vacuum fluctuations / transformations” show that T=0K isn’t abstraction
and “virtual particles” exist there and they can change situation for observation.
The “virtual particles” only seems to us abstractive.
As Niels Bohr wrote:
“ Everything we call real is made of things that cannot be regarded
as real. If quantum mechanics hasn't profoundly shocked you,
you haven't understood it yet.”
One fundamental constant ( c-1) after many years of doubt was adopted.
Sooner or later another fundamental constant of Nature: T=0K would be