We are less inclined to question the integrity of a system
that deliver correct answers to the questions asked. I am
sure nobody would deny that this is something the theories
of Special and General Relativity do just fine with the
result that Newtonian classic mechanics is reduced to a
special case of general relativity, only valid at speeds
much below the speed of light.
However General Relativity, while providing the right answers, does not explain much. It has nothing to say about quantum mechanics and does not offer any clue about the cause and mechanism of time-dilation, questions a deeper theory would be expected to answer.
A hot candidate for such a deeper theory is string theory provided certain problems that prohibit it to deliver any meaningful predictions could be addressed. In my opinion a starting point for doing that would be to investigate if the dynamics I am proposing on this site might provide a remedy for string theory.
On the other hand Newton's ideas about time and space are very close to those I am proposing, so with only minor adjustments Newton's classic mechanics would provide a playground for relativity as well as for string theory and quantum mechanics.
Newton had no reason to suspect anything else then that time and space would behave as his senses told him. That is also what he founded his mechanics on. The same idea about time and space with regard to the senses is actually carried over to relativity by Einstein, only he could show that at relativistic speeds one cannot rely on those senses. They actually fool us also at slower speeds, but the discrepancy is then so small that it can safely be neglected. This points of course to the present situation where consensus has it that relativity is the "deeper" theory with Newtonian mechanics only a special case of the same. A situation I would like to change, and the reason is simple. Neither Newton or Einstein actually had any clue about the "true" physical nature of time, but to me it seems that Newton was closest when he stated that "Absolute, true and mathematical time, of itself, and from its own nature flows equably without regard to anything external,....." I fully agree with all of that but again, the details need to be brought up to date.
With the fabric of our universe (Newtons absolute space) continuously oscillating in size as suggested, and the resulting ability for physical displacement of resonating vibrations in the fabric during each oscillation as the rather simple but "hidden" nature of time and motion, Newtons idea of absolute time in my mind has the upper hand over relativity. The insight that such rather violent oscillations of the fabric also can explain the existence of the quantum realm is only extra icing on the cake, not to mention that string theorists herewith have a more substantial ground to build on.
The same fundamental ground is valid for gravitation where
aggregated waves of matter cause an oscillating radial
motion in the surrounding fabric by pulling it towards the
center of the aggregation each oscillation, in the process
also accelerating all other waves in the affected fabric
towards that center.
As oscillations of waves go, this is an instant and simultaneous event that is taking place locally everywhere in that same oscillating wave during the course of each oscillation, seemingly non-local and not too different from Newtons idea of gravitation. They are however only local oscillations driven by resonance with the large Big Bang initiated oscillations of the fabric of our universe which, when viewed and plotted over any length of "time" (equal to a truly gigantic number of present moments), build up the geodetic "landscape" of gravitation Einstein presented us with in his theory of general relativity.
In other words, rather then following a "straight line" in the "curved space-time" of a gravitation field, the gravitating objects and the spots they occupy in the oscillating fabric is being pulled towards each other every present moment by the elastic motion of the fabric in which they are embedded.
With Newtons idea of time as the standard measure of
absolute duration, relativistic time instead measure dilated
duration or what might be called subjective duration. The
duration of moments become shorter the faster you travel and
"time" is only a succession of repeated durations.
The dilation effect is caused by the oscillations of any moving object being first slowed down to a full stop and then accelerated back up in speed again each moment, leaving less part of the moment free for doing anything else, like for instance measuring the sum of duration of the repeated durations, the local and subjective "time".
At the speed of light that sum of durations may be near to zero.