A Note About the Fundamental Relationship Between SRT, GRT and the Equivalence Principle, and QM.

Much effort is put into "deep" thinking to show the relationships between various aspects of theory and our world. Sometimes it can be done rather simply.  Years ago I conceived the following little thought experiment in "comparative physics" (imagining the implications of laws being otherwise.)  I don't have any idea who else might have also etc.  Let's suppose light propagated "ballistically" like in the Ritz theory.  (That means c' = c + v, so the speed of light is like a bullet in classical physics.  It clearly would not be a constant for all observers, nor like the ether theory where c is relative to a pervasive, fixed medium.)

Now let's apply ballistic light to the equivalence principle: we have a source at the bottom of an accelerating chamber, at some frequency ν.  Since the light is ballistic, each pulse takes the same time delay to catch up to the accelerating "top" end. That means there is no Doppler shift of frequency, even though there would presumably (depending on just how the Ritzian theory handles light) be a loss of energy equivalent to the change in gravitational potential.  This situation may be acceptable in terms of classical physics, but it won't do for quantum physics: if each pulse or photon carries a certain energy, and the energy is diminished by climbing up the relative g field, then the frequency should be slowed the same proportion according to U = hν.  Note: I tend to use "U" for energy because I like to save "E" for electric field.

Hence we see that SRT, GRT/EP, and QM form a sort of triangle of consistency.  We (or Nature) are not free to just, say, substitute classical velocity addition for light and expect things to stay the same in other areas.