Frame of Reference, Sun, Speed of Light

A Frame of Reference can be either fixed or variable.  So, Copernicus' revolutionary insight can be conceived as inverting the naively presumed fixed-variable relation of an Earthly observer and the Sun.  Now, Newton does not deny the existence of Frames of Reference; rather, his Absolutism consists in the thesis that there is exactly one fixed Frame of Reference--the entire system itself--one which is naively accepted as that of each observer.  But, the term 'Relativism' belies the presence in Einstein's system of one fixed Frame of Reference--the Speed of Light--a quantity that, in Newton's system, is variable, i. e. can be acted upon, and, hence, accelerated.  In other words, wittingly or otherwise, Einstein's Physics, is the result of an inversion similar to Copernicus', with the Speed of Light comprable to the Sun.