Quantum Mechanics asserts that a "particle" can be in two states at the same time, that it assumes one state only when observed. Two "entangled" particles communicate instantly their respective states if one is observed no matter the distance between them. A "particle" may be in two "places" at the same time, its position essentially a "wave" of probability.
Each requires the assumption that "time" is absolute.
What happens if time itself is indeterminate, flexible, malleable on a quantum scale? What happens to our ideas of particles? What happens to our miles per hour, feet per second, angstrom per attosecond if the denominator, the number below the slash, the devisor, is not fixed, if it can't be fixed, if it may be unknowable at all beyond a vague assumption? If it changes?
If our universe is of space-time and the cone of light speed defines causality, what happens to us if the speed of light is no longer absolute not because the distance covered is greater or less, but because the time it takes is constantly changing?
Everything happens at once.