This is the same kind of thing as used in Special Relativity.
Time appears to define our type of conciousness.
Without a continuous flow of time, our type of conciousness would not exist. Quoting Mr Einstein, the speed of light c is constant relative to the observer. All that is required is that all conciousnesses are testably consistent with each other. The transformation from one concious view to another is extremely weird. It is possible that the brain acts like a quantum mechanical system in which our conciousness is constantly collapsing the wavefunction.