On 23 Apr, 20:25, (G=EMC^2 Glazier) wrote:
How come I know why light has to be a constant? How come I know where
light got its constant speed.? How come I know why its so necessary not
for photons,or virtual photons to slow down or speed up?

Because you are only capable of thinking locally, and not capable of
understanding curvatures in the spacetime continuum itself.